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Sample records for blood-oxygenation-level-dependent contrast functional

  1. Brain magnetic resonance imaging with contrast dependent on blood oxygenation

    International Nuclear Information System (INIS)

    Ogawa, S.; Lee, T.M.; Kay, A.R.; Tank, D.W.

    1990-01-01

    Paramagnetic deoxyhemoglobin in venous blood is a naturally occurring contrast agent for magnetic resonance imaging (MRI). By accentuating the effects of this agent through the use of gradient-echo techniques in high yields, the authors demonstrate in vivo images of brain microvasculature with image contrast reflecting the blood oxygen level. This blood oxygenation level-dependent (BOLD) contrast follows blood oxygen changes induced by anesthetics, by insulin-induced hypoglycemia, and by inhaled gas mixtures that alter metabolic demand or blood flow. The results suggest that BOLD contrast can be used to provide in vivo real-time maps of blood oxygenation in the brain under normal physiological conditions. BOLD contrast adds an additional feature to magnetic resonance imaging and complement other techniques that are attempting to provide position emission tomography-like measurements related to regional neural activity

  2. Cerebral misery perfusion diagnosed using hypercapnic blood-oxygenation-level-dependent contrast functional magnetic resonance imaging: a case report

    Directory of Open Access Journals (Sweden)

    D'Souza Olympio

    2010-02-01

    Full Text Available Abstract Introduction Cerebral misery perfusion represents a failure of cerebral autoregulation. It is an important differential diagnosis in post-stroke patients presenting with collapses in the presence of haemodynamically significant cerebrovascular stenosis. This is particularly the case when cortical or internal watershed infarcts are present. When this condition occurs, further investigation should be done immediately. Case presentation A 50-year-old Caucasian man presented with a stroke secondary to complete occlusion of his left internal carotid artery. He went on to suffer recurrent seizures. Neuroimaging demonstrated numerous new watershed-territory cerebral infarcts. No source of arterial thromboembolism was demonstrable. Hypercapnic blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging was used to measure his cerebrovascular reserve capacity. The findings were suggestive of cerebral misery perfusion. Conclusions Blood-oxygenation-level-dependent-contrast functional magnetic resonance imaging allows the inference of cerebral misery perfusion. This procedure is cheaper and more readily available than positron emission tomography imaging, which is the current gold standard diagnostic test. The most evaluated treatment for cerebral misery perfusion is extracranial-intracranial bypass. Although previous trials of this have been unfavourable, the results of new studies involving extracranial-intracranial bypass in high-risk patients identified during cerebral perfusion imaging are awaited. Cerebral misery perfusion is an important and under-recognized condition in which emerging imaging and treatment modalities present the possibility of practical and evidence-based management in the near future. Physicians should thus be aware of this disorder and of recent developments in diagnostic tests that allow its detection.

  3. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications; Blood Oxygenation Level Dependent (BOLD). Bildgebung der Nieren. Konzepte und Anwendungen

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    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J. [Heidelberg Univ. Medizinische Fakultaet Mannheim (Germany). Inst. fuer Klinische Radiologie und Nuklearmedizin; Mie, Moritz B.; Zoellner, Frank G. [Heidelberg Univ. Medizinische Fakultaet Mannheim (DE). Inst. fuer Computerunterstuetzte Klinische Medizin (CKM)

    2010-07-01

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2{sup *}-weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  4. Blood oxygenation level dependent (BOLD). Renal imaging. Concepts and applications

    International Nuclear Information System (INIS)

    Nissen, Johanna C.; Haneder, Stefan; Schoenberg, Stefan O.; Michaely, Henrik J.

    2010-01-01

    Many renal diseases as well as several pharmacons cause a change in renal blood flow and/or renal oxygenation. The blood oxygenation level dependent (BOLD) imaging takes advantage of local field inhomogeneities and is based on a T2 * -weighted sequence. BOLD is a non-invasive method allowing an estimation of the renal, particularly the medullary oxygenation, and an indirect measurement of blood flow without administration of contrast agents. Thus, effects of different drugs on the kidney and various renal diseases can be controlled and observed. This work will provide an overview of the studies carried out so far and identify ways how BOLD can be used in clinical studies. (orig.)

  5. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    OpenAIRE

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess...

  6. Correlation between single-trial visual evoked potentials and the blood oxygenation level dependent response in simultaneously recorded electroencephalography-functional magnetic resonance imaging

    DEFF Research Database (Denmark)

    Fuglø, Dan; Pedersen, Henrik; Rostrup, Egill

    2012-01-01

    in different occipital and extraoccipital cortical areas not explained by the boxcar regressor. The results suggest that the P1-N2 regressor is the best EEG-based regressor to model the visual paradigm, but when looking for additional effects like habituation or attention modulation that cannot be modeled......To compare different electroencephalography (EEG)-based regressors and their ability to predict the simultaneously recorded blood oxygenation level dependent response during blocked visual stimulation, simultaneous EEG-functional magnetic resonance imaging in 10 healthy volunteers was performed....... The performance of different single-trial EEG regressors was compared in terms of predicting the measured blood oxygenation level dependent response. The EEG-based regressors were the amplitude and latency of the primary positive (P1) and negative (N2) peaks of the visual evoked potential, the combined P1-N2...

  7. Functional neuroanatomy in depressed patients with sexual dysfunction: blood oxygenation level dependent functional MR imaging

    International Nuclear Information System (INIS)

    Yang, Jong Chul

    2004-01-01

    To demonstrate the functional neuroanatomy associated with sexual arousal visually evoked in depressed males who have underlying sexual dysfunction using Blood Oxygenation Level Dependent-based fMRI. Ten healthy volunteers (age range 21-55: mean 32.5 years), and 10 depressed subjects (age range 23-51: mean 34.4 years, mean Beck Depression Inventory score of 39.6 ± 5.9, mean Hamilton Rating Scale Depression (HAMD)-17 score of 33.5 ± 6.0) with sexual arousal dysfunction viewed erotic and neutral video films during functional magnetic resonance imaging (fMRI) with 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 oblique planes using gradient-echo EPI (flip angle/TR/TE=90 .deg. /6000 ms/50 ms). The visual stimulation paradigm began with 60 sec of black screen, 150 sec of neutral stimulation with a documentary video film, 30 sec of black screen, 150 sec of sexual stimulation with an erotic video film followed by 30 sec of black screen. The brain activation maps and their quantification were analyzed by SPM99 program. There was a significant difference of brain activation between two groups during visual sexual stimulation. In depressed subjects, the level of activation during the visually evoked sexual arousal was significantly less than that of healthy volunteers, especially in the cerebrocortical areas of the hypothalamus, thalamus, caudate nucleus, and inferior and superior temporal gyri. On the other hand, the cerebral activation patterns during the neutral condition in both groups showed no significant differences (ρ < 0.01). This study is the first demonstration of the functional neuroanatomy of the brain associated with sexual dysfunction in depressed patients using fMRI. In order to validate our physiological neuroscience results, further studies that would include patients with other disorders and sexual dysfunction, and depressed patients without sexual dysfunction and their treatment response are needed

  8. Functional neuroanatomy in depressed patients with sexual dysfunction: blood oxygenation level dependent functional MR imaging

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    Yang, Jong Chul [Chonnam National Univ. Hospital, Kwangju (Korea, Republic of)

    2004-06-15

    To demonstrate the functional neuroanatomy associated with sexual arousal visually evoked in depressed males who have underlying sexual dysfunction using Blood Oxygenation Level Dependent-based fMRI. Ten healthy volunteers (age range 21-55: mean 32.5 years), and 10 depressed subjects (age range 23-51: mean 34.4 years, mean Beck Depression Inventory score of 39.6 {+-} 5.9, mean Hamilton Rating Scale Depression (HAMD)-17 score of 33.5 {+-} 6.0) with sexual arousal dysfunction viewed erotic and neutral video films during functional magnetic resonance imaging (fMRI) with 1.5 T MR scanner (GE Signa Horizon). The fMRI data were obtained from 7 oblique planes using gradient-echo EPI (flip angle/TR/TE=90 .deg. /6000 ms/50 ms). The visual stimulation paradigm began with 60 sec of black screen, 150 sec of neutral stimulation with a documentary video film, 30 sec of black screen, 150 sec of sexual stimulation with an erotic video film followed by 30 sec of black screen. The brain activation maps and their quantification were analyzed by SPM99 program. There was a significant difference of brain activation between two groups during visual sexual stimulation. In depressed subjects, the level of activation during the visually evoked sexual arousal was significantly less than that of healthy volunteers, especially in the cerebrocortical areas of the hypothalamus, thalamus, caudate nucleus, and inferior and superior temporal gyri. On the other hand, the cerebral activation patterns during the neutral condition in both groups showed no significant differences ({rho} < 0.01). This study is the first demonstration of the functional neuroanatomy of the brain associated with sexual dysfunction in depressed patients using fMRI. In order to validate our physiological neuroscience results, further studies that would include patients with other disorders and sexual dysfunction, and depressed patients without sexual dysfunction and their treatment response are needed.

  9. Multi-regional investigation of the relationship between functional MRI blood oxygenation level dependent (BOLD activation and GABA concentration.

    Directory of Open Access Journals (Sweden)

    Ashley D Harris

    Full Text Available Several recent studies have reported an inter-individual correlation between regional GABA concentration, as measured by MRS, and the amplitude of the functional blood oxygenation level dependent (BOLD response in the same region. In this study, we set out to investigate whether this coupling generalizes across cortex. In 18 healthy participants, we performed edited MRS measurements of GABA and BOLD-fMRI experiments using regionally related activation paradigms. Regions and tasks were the: occipital cortex with a visual grating stimulus; auditory cortex with a white noise stimulus; sensorimotor cortex with a finger-tapping task; frontal eye field with a saccade task; and dorsolateral prefrontal cortex with a working memory task. In contrast to the prior literature, no correlation between GABA concentration and BOLD activation was detected in any region. The origin of this discrepancy is not clear. Subtle differences in study design or insufficient power may cause differing results; these and other potential reasons for the discrepant results are discussed. This negative result, although it should be interpreted with caution, has a larger sample size than prior positive results, and suggests that the relationship between GABA and the BOLD response may be more complex than previously thought.

  10. The Not-So-Global Blood Oxygen Level-Dependent Signal.

    Science.gov (United States)

    Billings, Jacob; Keilholz, Shella

    2018-04-01

    Global signal regression is a controversial processing step for resting-state functional magnetic resonance imaging, partly because the source of the global blood oxygen level-dependent (BOLD) signal remains unclear. On the one hand, nuisance factors such as motion can readily introduce coherent BOLD changes across the whole brain. On the other hand, the global signal has been linked to neural activity and vigilance levels, suggesting that it contains important neurophysiological information and should not be discarded. Any widespread pattern of coordinated activity is likely to contribute appreciably to the global signal. Such patterns may include large-scale quasiperiodic spatiotemporal patterns, known also to be tied to performance on vigilance tasks. This uncertainty surrounding the separability of the global BOLD signal from concurrent neurological processes motivated an examination of the global BOLD signal's spatial distribution. The results clarify that although the global signal collects information from all tissue classes, a diverse subset of the BOLD signal's independent components contribute the most to the global signal. Further, the timing of each network's contribution to the global signal is not consistent across volunteers, confirming the independence of a constituent process that comprises the global signal.

  11. Blood oxygen-level dependent functional assessment of cerebrovascular reactivity: Feasibility for intraoperative 3 Tesla MRI.

    Science.gov (United States)

    Fierstra, Jorn; Burkhardt, Jan-Karl; van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Pangalu, Athina; Kocian, Roman; Neidert, Marian Christoph; Valavanis, Antonios; Regli, Luca; Bozinov, Oliver

    2017-02-01

    To assess the feasibility of functional blood oxygen-level dependent (BOLD) MRI to evaluate intraoperative cerebrovascular reactivity (CVR) at 3 Tesla field strength. Ten consecutive neurosurgical subjects scheduled for a clinical intraoperative MRI examination were enrolled in this study. In addition to the clinical protocol a BOLD sequence was implemented with three cycles of 44 s apnea to calculate CVR values on a voxel-by-voxel basis throughout the brain. The CVR range was then color-coded and superimposed on an anatomical volume to create high spatial resolution CVR maps. Ten subjects (mean age 34.8 ± 13.4; 2 females) uneventfully underwent the intraoperative BOLD protocol, with no complications occurring. Whole-brain CVR for all subjects was (mean ± SD) 0.69 ± 0.42, whereas CVR was markedly higher for tumor subjects as compared to vascular subjects, 0.81 ± 0.44 versus 0.33 ± 0.10, respectively. Furthermore, color-coded functional maps could be robustly interpreted for a whole-brain assessment of CVR. We demonstrate that intraoperative BOLD MRI is feasible in creating functional maps to assess cerebrovascular reactivity throughout the brain in subjects undergoing a neurosurgical procedure. Magn Reson Med 77:806-813, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  12. Mapping of cerebral metabolic rate of oxygen using dynamic susceptibility contrast and blood oxygen level dependent MR imaging in acute ischemic stroke

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    Gersing, Alexandra S.; Schwaiger, Benedikt J. [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); University of California, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Ankenbrank, Monika; Toth, Vivien; Bauer, Jan S.; Zimmer, Claus [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Janssen, Insa [Technical University Munich, Department of Neurosurgery, Munich (Germany); Kooijman, Hendrik [Philips Healthcare, Hamburg (Germany); Wunderlich, Silke [Technical University Munich, Department of Neurology, Munich (Germany); Preibisch, Christine [Technical University Munich, Klinikum rechts der Isar, Department of Neuroradiology, Munich (Germany); Technical University Munich, Department of Neurology, Munich (Germany)

    2015-12-15

    MR-derived cerebral metabolic rate of oxygen utilization (CMRO{sub 2}) has been suggested to be analogous to PET-derived CMRO{sub 2} and therefore may be used for detection of viable tissue at risk for infarction. The purpose of this study was to evaluate MR-derived CMRO{sub 2} mapping in acute ischemic stroke in relation to established diffusion- and perfusion-weighted imaging. In 23 patients (mean age 63 ± 18.7 years, 11 women) with imaging findings for acute ischemic stroke, relative oxygen extraction fraction was calculated from quantitative transverse relaxation times (T2, T2*) and relative cerebral blood volume using a quantitative blood oxygenation level dependent (BOLD) approach in order to detect a local increase of deoxyhemoglobin. Relative CMRO{sub 2} (rCMRO{sub 2}) maps were calculated by multiplying relative oxygen extraction fraction (rOEF) by cerebral blood flow, derived from PWI. After co-registration, rCMRO{sub 2} maps were evaluated in comparison with apparent diffusion coefficient (ADC) and time-to-peak (TTP) maps. Mean rCMRO{sub 2} values in areas with diffusion-restriction or TTP/ADC mismatch were compared with rCMRO{sub 2} values in the contralateral tissue. In tissue with diffusion restriction, mean rCMRO{sub 2} values were significantly decreased compared to perfusion-impaired (17.9 [95 % confidence interval 10.3, 25.0] vs. 58.1 [95 % confidence interval 50.1, 70.3]; P < 0.001) and tissue in the contralateral hemisphere (68.2 [95 % confidence interval 61.4, 75.0]; P < 0.001). rCMRO{sub 2} in perfusion-impaired tissue showed no significant change compared to tissue in the contralateral hemisphere (58.1 [95 % confidence interval 50.1, 70.3] vs. 66.7 [95 % confidence interval 53.4, 73.4]; P = 0.34). MR-derived CMRO{sub 2} was decreased within diffusion-restricted tissue and stable within perfusion-impaired tissue, suggesting that this technique may be adequate to reveal different pathophysiological stages in acute stroke. (orig.)

  13. Effects of anesthetic agents on brain blood oxygenation level revealed with ultra-high field MRI

    International Nuclear Information System (INIS)

    Ciobanu, Luisa; Reynaud, Olivier; Le Bihan, Denis; Uhrig, Lynn; Jarraya, Bechir

    2012-01-01

    During general anesthesia it is crucial to control systemic hemodynamics and oxygenation levels. However, anesthetic agents can affect cerebral hemodynamics and metabolism in a drug-dependent manner, while systemic hemodynamics is stable. Brain-wide monitoring of this effect remains highly challenging. Because T2'*-weighted imaging at ultra-high magnetic field strengths benefits from a dramatic increase in contrast to noise ratio, we hypothesized that it could monitor anesthesia effects on brain blood oxygenation. We scanned rat brains at 7 T and 17.2 T under general anesthesia using different anesthetics (isoflurane, ketamine-xylazine, medetomidine). We showed that the brain/vessels contrast in T2'*- weighted images at 17.2 T varied directly according to the applied pharmacological anesthetic agent, a phenomenon that was visible, but to a much smaller extent at 7 T. This variation is in agreement with the mechanism of action of these agents. These data demonstrate that preclinical ultra-high field MRI can monitor the effects of a given drug on brain blood oxygenation level in the absence of systemic blood oxygenation changes and of any neural stimulation. (authors)

  14. Measuring vascular reactivity with resting-state blood oxygenation level-dependent (BOLD) signal fluctuations: A potential alternative to the breath-holding challenge?

    Science.gov (United States)

    Jahanian, Hesamoddin; Christen, Thomas; Moseley, Michael E; Pajewski, Nicholas M; Wright, Clinton B; Tamura, Manjula K; Zaharchuk, Greg

    2017-07-01

    Measurement of the ability of blood vessels to dilate and constrict, known as vascular reactivity, is often performed with breath-holding tasks that transiently raise arterial blood carbon dioxide (P a CO 2 ) levels. However, following the proper commands for a breath-holding experiment may be difficult or impossible for many patients. In this study, we evaluated two approaches for obtaining vascular reactivity information using blood oxygenation level-dependent signal fluctuations obtained from resting-state functional magnetic resonance imaging data: physiological fluctuation regression and coefficient of variation of the resting-state functional magnetic resonance imaging signal. We studied a cohort of 28 older adults (69 ± 7 years) and found that six of them (21%) could not perform the breath-holding protocol, based on an objective comparison with an idealized respiratory waveform. In the subjects that could comply, we found a strong linear correlation between data extracted from spontaneous resting-state functional magnetic resonance imaging signal fluctuations and the blood oxygenation level-dependent percentage signal change during breath-holding challenge ( R 2  = 0.57 and 0.61 for resting-state physiological fluctuation regression and resting-state coefficient of variation methods, respectively). This technique may eliminate the need for subject cooperation, thus allowing the evaluation of vascular reactivity in a wider range of clinical and research conditions in which it may otherwise be impractical.

  15. Effects of anesthetic agents on brain blood oxygenation level revealed with ultra-high field MRI.

    Directory of Open Access Journals (Sweden)

    Luisa Ciobanu

    Full Text Available During general anesthesia it is crucial to control systemic hemodynamics and oxygenation levels. However, anesthetic agents can affect cerebral hemodynamics and metabolism in a drug-dependent manner, while systemic hemodynamics is stable. Brain-wide monitoring of this effect remains highly challenging. Because T(2*-weighted imaging at ultra-high magnetic field strengths benefits from a dramatic increase in contrast to noise ratio, we hypothesized that it could monitor anesthesia effects on brain blood oxygenation. We scanned rat brains at 7T and 17.2T under general anesthesia using different anesthetics (isoflurane, ketamine-xylazine, medetomidine. We showed that the brain/vessels contrast in T(2*-weighted images at 17.2T varied directly according to the applied pharmacological anesthetic agent, a phenomenon that was visible, but to a much smaller extent at 7T. This variation is in agreement with the mechanism of action of these agents. These data demonstrate that preclinical ultra-high field MRI can monitor the effects of a given drug on brain blood oxygenation level in the absence of systemic blood oxygenation changes and of any neural stimulation.

  16. Theoretical model for optical oximetry at the capillary level: exploring hemoglobin oxygen saturation through backscattering of single red blood cells

    Science.gov (United States)

    Liu, Rongrong; Spicer, Graham; Chen, Siyu; Zhang, Hao F.; Yi, Ji; Backman, Vadim

    2017-02-01

    Oxygen saturation (sO2) of red blood cells (RBCs) in capillaries can indirectly assess local tissue oxygenation and metabolic function. For example, the altered retinal oxygenation in diabetic retinopathy and local hypoxia during tumor development in cancer are reflected by abnormal sO2 of local capillary networks. However, it is far from clear whether accurate label-free optical oximetry (i.e., measuring hemoglobin sO2) is feasible from dispersed RBCs at the single capillary level. The sO2-dependent hemoglobin absorption contrast present in optical scattering signal is complicated by geometry-dependent scattering from RBCs. We present a numerical study of backscattering spectra from single RBCs based on the first-order Born approximation, considering practical factors: RBC orientations, size variation, and deformations. We show that the oscillatory spectral behavior of RBC geometries is smoothed by variations in cell size and orientation, resulting in clear sO2-dependent spectral contrast. In addition, this spectral contrast persists with different mean cellular hemoglobin content and different deformations of RBCs. This study shows for the first time the feasibility of, and provides a theoretical model for, label-free optical oximetry at the single capillary level using backscattering-based imaging modalities, challenging the popular view that such measurements are impossible at the single capillary level.

  17. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation.

    Science.gov (United States)

    Licata, Stephanie C; Lowen, Steven B; Trksak, George H; Maclean, Robert R; Lukas, Scott E

    2011-08-15

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABA(A) receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 min after acute oral administration of zolpidem (0, 5, 10, or 20mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem's modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABA(A) receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation. Copyright © 2011 Elsevier Inc. All rights reserved.

  18. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation

    Science.gov (United States)

    Licata, Stephanie C.; Lowen, Steven B.; Trksak, George H.; MacLean, Robert R.; Lukas, Scott E.

    2011-01-01

    Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABAA receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 minutes after acute oral administration of zolpidem (0, 5, 10, or 20 mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20 mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem’s modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABAA receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation. PMID:21640782

  19. Negative blood oxygen level dependent signals during speech comprehension.

    Science.gov (United States)

    Rodriguez Moreno, Diana; Schiff, Nicholas D; Hirsch, Joy

    2015-05-01

    Speech comprehension studies have generally focused on the isolation and function of regions with positive blood oxygen level dependent (BOLD) signals with respect to a resting baseline. Although regions with negative BOLD signals in comparison to a resting baseline have been reported in language-related tasks, their relationship to regions of positive signals is not fully appreciated. Based on the emerging notion that the negative signals may represent an active function in language tasks, the authors test the hypothesis that negative BOLD signals during receptive language are more associated with comprehension than content-free versions of the same stimuli. Regions associated with comprehension of speech were isolated by comparing responses to passive listening to natural speech to two incomprehensible versions of the same speech: one that was digitally time reversed and one that was muffled by removal of high frequencies. The signal polarity was determined by comparing the BOLD signal during each speech condition to the BOLD signal during a resting baseline. As expected, stimulation-induced positive signals relative to resting baseline were observed in the canonical language areas with varying signal amplitudes for each condition. Negative BOLD responses relative to resting baseline were observed primarily in frontoparietal regions and were specific to the natural speech condition. However, the BOLD signal remained indistinguishable from baseline for the unintelligible speech conditions. Variations in connectivity between brain regions with positive and negative signals were also specifically related to the comprehension of natural speech. These observations of anticorrelated signals related to speech comprehension are consistent with emerging models of cooperative roles represented by BOLD signals of opposite polarity.

  20. Methods of Blood Oxygen Level-Dependent Magnetic Resonance Imaging Analysis for Evaluating Renal Oxygenation

    Directory of Open Access Journals (Sweden)

    Fen Chen

    2018-03-01

    Full Text Available Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI has recently been utilized as a noninvasive tool for evaluating renal oxygenation. Several methods have been proposed for analyzing BOLD images. Regional ROI selection is the earliest and most widely used method for BOLD analysis. In the last 20 years, many investigators have used this method to evaluate cortical and medullary oxygenation in patients with ischemic nephropathy, hypertensive nephropathy, diabetic nephropathy, chronic kidney disease (CKD, acute kidney injury and renal allograft rejection. However, clinical trials of BOLD MRI using regional ROI selection revealed that it was difficult to distinguish the renal cortico-medullary zones with this method, and that it was susceptible to observer variability. To overcome these deficiencies, several new methods were proposed for analyzing BOLD images, including the compartmental approach, fractional hypoxia method, concentric objects (CO method and twelve-layer concentric objects (TLCO method. The compartmental approach provides an algorithm to judge whether the pixel belongs to the cortex or medulla. Fractional kidney hypoxia, measured by using BOLD MRI, was negatively correlated with renal blood flow, tissue perfusion and glomerular filtration rate (GFR in patients with atherosclerotic renal artery stenosis. The CO method divides the renal parenchyma into six or twelve layers of thickness in each coronal slice of BOLD images and provides a R2* radial profile curve. The slope of the R2* curve associated positively with eGFR in CKD patients. Indeed, each method invariably has advantages and disadvantages, and there is generally no consensus method so far. Undoubtedly, analytic approaches for BOLD MRI with better reproducibility would assist clinicians in monitoring the degree of kidney hypoxia and thus facilitating timely reversal of tissue hypoxia.

  1. Combined diffusion-weighted, blood oxygen level-dependent, and dynamic contrast-enhanced MRI for characterization and differentiation of renal cell carcinoma.

    Science.gov (United States)

    Notohamiprodjo, Mike; Staehler, Michael; Steiner, Nicole; Schwab, Felix; Sourbron, Steven P; Michaely, Henrik J; Helck, Andreas D; Reiser, Maximilian F; Nikolaou, Konstantin

    2013-06-01

    To investigate a multiparametric magnetic resonance imaging (MRI) approach comprising diffusion-weighted imaging (DWI), blood oxygen-dependent (BOLD), and dynamic contrast-enhanced (DCE) MRI for characterization and differentiation of primary renal cell carcinoma (RCC). Fourteen patients with clear-cell carcinoma and four patients with papillary RCC were examined with DWI, BOLD MRI, and DCE MRI at 1.5T. The apparent diffusion coefficient (ADC) was calculated with a monoexponential decay. The spin-dephasing rate R2* was derived from parametric R2* maps. DCE-MRI was analyzed using a two-compartment exchange model allowing separation of perfusion (plasma flow [FP] and plasma volume [VP]), permeability (permeability surface area product [PS]), and extravascular extracellular volume (VE). Statistical analysis was performed with Wilcoxon signed-rank test, Pearson's correlation coefficient, and receiver operating characteristic curve analysis. Clear-cell RCC showed higher ADC and lower R2* compared to papillary subtypes, but differences were not significant. FP of clear-cell subtypes was significantly higher than in papillary RCC. Perfusion parameters showed moderate but significant inverse correlation with R2*. VE showed moderate inverse correlation with ADC. Fp and Vp showed best sensitivity for histological differentiation. Multiparametric MRI comprising DWI, BOLD, and DCE MRI is feasible for assessment of primary RCC. BOLD moderately correlates to DCE MRI-derived perfusion. ADC shows moderate correlation to the extracellular volume, but does not correlate to tumor oxygenation or perfusion. In this preliminary study DCE-MRI appeared superior to BOLD and DWI for histological differentiation. Copyright © 2013 AUR. Published by Elsevier Inc. All rights reserved.

  2. Detection of Acute Tubular Necrosis Using Blood Oxygenation Level-Dependent (BOLD MRI

    Directory of Open Access Journals (Sweden)

    Frederic Bauer

    2017-12-01

    Full Text Available Background/Aims: To date, there is no imaging technique to assess tubular function in vivo. Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI measures tissue oxygenation based on the transverse relaxation rate (R2*. The present study investigates whether BOLD MRI can assess tubular function using a tubule-specific pharmacological maneuver. Methods: Cross sectional study with 28 participants including 9 subjects with ATN-induced acute kidney injury (AKI, 9 healthy controls, and 10 subjects with nephron sparing tumor resection (NSS with clamping of the renal artery serving as a model of ischemia/reperfusion (I/R-induced subclinical ATN (median clamping time 15 min, no significant decrease of eGFR, p=0.14. BOLD MRI was performed before and 5, 7, and 10 min after intravenous administration of 40 mg furosemide. Results: Urinary neutrophil gelatinase-associated lipocalin was significantly higher in ATN-induced AKI and NSS subjects than in healthy controls (p=0.03 and p=0.01, respectively. Before administration of furosemide, absolute medullary R2*, cortical R2*, and medullary/cortical R2* ratio did not significantly differ between ATN-induced AKI vs. healthy controls and between NSS-I/R vs. contralateral healthy kidneys (p>0.05 each. Furosemide led to a significant decrease in the medullary and cortical R2* of healthy subjects and NSS contralateral kidneys (p<0.05 each, whereas there was no significant change of R2* in ATN-induced AKI and the NSS-I/R kidneys (p>0.05 each. Conclusion: BOLD-MRI is able to detect even mild tubular injury but necessitates a tubule-specific pharmacological maneuver, e.g. blocking the Na+-K+-2Cl- transporter by furosemide.

  3. Megalophallus as a sequela of priapism in sickle cell anemia: use of blood oxygen level-dependent magnetic resonance imaging.

    Science.gov (United States)

    Kassim, A A; Umans, H; Nagel, R L; Fabry, M E

    2000-09-01

    Priapism is a common complication of sickle cell anemia. We report a little known sequela of priapism: painless megalophallus, with significant penile enlargement. The patient had had an intense episode of priapism 9 years previously and his penis remained enlarged. Blood oxygen level-dependent magnetic resonance imaging revealed enlarged, hypoxic corpora cavernosa. Megalophallus probably resulted from permanent loss of elasticity of the tunica albuginea due to severe engorgement during the episode of priapism. This sequela needs to be recognized by physicians because no intervention is necessary and sexual function seems to remain intact.

  4. Complexity of low-frequency blood oxygen level-dependent fluctuations covaries with local connectivity.

    Science.gov (United States)

    Anderson, Jeffrey S; Zielinski, Brandon A; Nielsen, Jared A; Ferguson, Michael A

    2014-04-01

    Very low-frequency blood oxygen level-dependent (BOLD) fluctuations have emerged as a valuable tool for describing brain anatomy, neuropathology, and development. Such fluctuations exhibit power law frequency dynamics, with largest amplitude at lowest frequencies. The biophysical mechanisms generating such fluctuations are poorly understood. Using publicly available data from 1,019 subjects of age 7-30, we show that BOLD fluctuations exhibit temporal complexity that is linearly related to local connectivity (regional homogeneity), consistently and significantly covarying across subjects and across gray matter regions. This relationship persisted independently of covariance with gray matter density or standard deviation of BOLD signal. During late neurodevelopment, BOLD fluctuations were unchanged with age in association cortex while becoming more random throughout the rest of the brain. These data suggest that local interconnectivity may play a key role in establishing the complexity of low-frequency BOLD fluctuations underlying functional magnetic resonance imaging connectivity. Stable low-frequency power dynamics may emerge through segmentation and integration of connectivity during development of distributed large-scale brain networks. Copyright © 2013 Wiley Periodicals, Inc.

  5. Synthetic generation of myocardial blood-oxygen-level-dependent MRI time series via structural sparse decomposition modeling.

    Science.gov (United States)

    Rusu, Cristian; Morisi, Rita; Boschetto, Davide; Dharmakumar, Rohan; Tsaftaris, Sotirios A

    2014-07-01

    This paper aims to identify approaches that generate appropriate synthetic data (computer generated) for cardiac phase-resolved blood-oxygen-level-dependent (CP-BOLD) MRI. CP-BOLD MRI is a new contrast agent- and stress-free approach for examining changes in myocardial oxygenation in response to coronary artery disease. However, since signal intensity changes are subtle, rapid visualization is not possible with the naked eye. Quantifying and visualizing the extent of disease relies on myocardial segmentation and registration to isolate the myocardium and establish temporal correspondences and ischemia detection algorithms to identify temporal differences in BOLD signal intensity patterns. If transmurality of the defect is of interest pixel-level analysis is necessary and thus a higher precision in registration is required. Such precision is currently not available affecting the design and performance of the ischemia detection algorithms. In this work, to enable algorithmic developments of ischemia detection irrespective to registration accuracy, we propose an approach that generates synthetic pixel-level myocardial time series. We do this by 1) modeling the temporal changes in BOLD signal intensity based on sparse multi-component dictionary learning, whereby segmentally derived myocardial time series are extracted from canine experimental data to learn the model; and 2) demonstrating the resemblance between real and synthetic time series for validation purposes. We envision that the proposed approach has the capacity to accelerate development of tools for ischemia detection while markedly reducing experimental costs so that cardiac BOLD MRI can be rapidly translated into the clinical arena for the noninvasive assessment of ischemic heart disease.

  6. The Relationship Between Dopamine Neurotransmitter Dynamics and the Blood-Oxygen-Level-Dependent (BOLD Signal: A Review of Pharmacological Functional Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    Tyler J. Bruinsma

    2018-04-01

    Full Text Available Functional magnetic resonance imaging (fMRI is widely used in investigations of normal cognition and brain disease and in various clinical applications. Pharmacological fMRI (pharma-fMRI is a relatively new application, which is being used to elucidate the effects and mechanisms of pharmacological modulation of brain activity. Characterizing the effects of neuropharmacological agents on regional brain activity using fMRI is challenging because drugs modulate neuronal function in a wide variety of ways, including through receptor agonist, antagonist, and neurotransmitter reuptake blocker events. Here we review current knowledge on neurotransmitter-mediated blood-oxygen-level dependent (BOLD fMRI mechanisms as well as recently updated methodologies aimed at more fully describing the effects of neuropharmacologic agents on the BOLD signal. We limit our discussion to dopaminergic signaling as a useful lens through which to analyze and interpret neurochemical-mediated changes in the hemodynamic BOLD response. We also discuss the need for future studies that use multi-modal approaches to expand the understanding and application of pharma-fMRI.

  7. Vascular Steal Explains Early Paradoxical Blood Oxygen Level-Dependent Cerebrovascular Response in Brain Regions with Delayed Arterial Transit Times

    Directory of Open Access Journals (Sweden)

    Julien Poublanc

    2013-04-01

    Full Text Available Introduction: Blood oxygen level-dependent (BOLD magnetic resonance imaging (MRI during manipulation of inhaled carbon dioxide (CO2 can be used to measure cerebrovascular reactivity (CVR and map regions of exhausted cerebrovascular reserve. These regions exhibit a reduced or negative BOLD response to inhaled CO2. In this study, we sought to clarify the mechanism behind the negative BOLD response by investigating its time delay (TD. Dynamic susceptibility contrast (DSC MRI with the injection of a contrast agent was used as the gold standard in order to provide measurement of the blood arrival time to which CVR TD could be compared. We hypothesize that if negative BOLD responses are the result of a steal phenomenon, they should be synchronized with positive BOLD responses from healthy brain tissue, even though the blood arrival time would be delayed. Methods: On a 3-tesla MRI system, BOLD CVR and DSC images were collected in a group of 19 patients with steno-occlusive cerebrovascular disease. For each patient, we generated a CVR magnitude map by regressing the BOLD signal with the end-tidal partial pressure of CO2 (PETCO2, and a CVR TD map by extracting the time of maximum cross-correlation between the BOLD signal and PETCO2. In addition, a blood arrival time map was generated by fitting the DSC signal with a gamma variate function. ROI masks corresponding to varying degrees of reactivity were constructed. Within these masks, the mean CVR magnitude, CVR TD and DSC blood arrival time were extracted and averaged over the 19 patients. CVR magnitude and CVR TD were then plotted against DSC blood arrival time. Results: The results show that CVR magnitude is highly correlated to DSC blood arrival time. As expected, the most compromised tissues with the longest blood arrival time have the lowest (most negative CVR magnitude. However, CVR TD shows a noncontinuous relationship with DSC blood arrival time. CVR TD is well correlated to DSC blood arrival time

  8. Arterial Spin Labeling and Blood Oxygen Level-Dependent MRI Cerebrovascular Reactivity in Cerebrovascular Disease

    DEFF Research Database (Denmark)

    Smeeing, Diederik P J; Hendrikse, Jeroen; Petersen, Esben T

    2016-01-01

    BACKGROUND: The cerebrovascular reactivity (CVR) results of blood oxygen level-dependent (BOLD) and arterial spin labeling (ASL) MRI studies performed in patients with cerebrovascular disease (steno-occlusive vascular disease or stroke) were systematically reviewed. SUMMARY: Thirty-one articles...... found a significant lower ASL CVR in the ipsilateral hemispheres of patients compared to controls. KEY MESSAGES: This review brings support for a reduced BOLD and ASL CVR in the ipsilateral hemisphere of patients with cerebrovascular disease. We suggest that future studies will be performed in a uniform...... way so reference values can be established and could be used to guide treatment decisions in patients with cerebrovascular disease....

  9. Blood banking-induced alteration of red blood cell oxygen release ability.

    Science.gov (United States)

    Li, Yaojin; Xiong, Yanlian; Wang, Ruofeng; Tang, Fuzhou; Wang, Xiang

    2016-05-01

    Current blood banking procedures may not fully preserve red blood cell (RBC) function during storage, contributing to the decrease of RBC oxygen release ability. This study was undertaken to evaluate the impact of routine cold storage on RBC oxygen release ability. RBC units were collected from healthy donors and each unit was split into two parts (whole blood and suspended RBC) to exclude possible donor variability. Oxygen dissociation measurements were performed on blood units stored at 4 °C during a 5-week period. 2,3-diphosphoglycerate levels and fluorescent micrographs of erythrocyte band 3 were also analysed. P50 and oxygen release capacity decreased rapidly during the first 3 weeks, and then did not change significantly. In contrast, the kinetic properties (PO2-t curve and T*50) of oxygen release changed slowly during the first 3 weeks of storage, but then decreased significantly in the last 2 weeks. 2,3-diphosphoglycerate decreased quickly during the first 3 weeks of storage to almost undetectable levels. Band 3 aggregated significantly during the last 2 weeks of storage. RBC oxygen release ability appears to be sensitive to routine cold storage. The thermodynamic characteristics of RBC oxygen release ability changed mainly in the first 3 weeks of storage, due to the decrease of 2,3-diphosphoglycerate, whereas the kinetic characteristics of RBC oxygen release ability decreased significantly at the end of storage, probably affected by alterations of band 3.

  10. Cerebral Metabolic Rate of Oxygen (CMRO2 ) Mapping by Combining Quantitative Susceptibility Mapping (QSM) and Quantitative Blood Oxygenation Level-Dependent Imaging (qBOLD).

    Science.gov (United States)

    Cho, Junghun; Kee, Youngwook; Spincemaille, Pascal; Nguyen, Thanh D; Zhang, Jingwei; Gupta, Ajay; Zhang, Shun; Wang, Yi

    2018-03-07

    To map the cerebral metabolic rate of oxygen (CMRO 2 ) by estimating the oxygen extraction fraction (OEF) from gradient echo imaging (GRE) using phase and magnitude of the GRE data. 3D multi-echo gradient echo imaging and perfusion imaging with arterial spin labeling were performed in 11 healthy subjects. CMRO 2 and OEF maps were reconstructed by joint quantitative susceptibility mapping (QSM) to process GRE phases and quantitative blood oxygen level-dependent (qBOLD) modeling to process GRE magnitudes. Comparisons with QSM and qBOLD alone were performed using ROI analysis, paired t-tests, and Bland-Altman plot. The average CMRO 2 value in cortical gray matter across subjects were 140.4 ± 14.9, 134.1 ± 12.5, and 184.6 ± 17.9 μmol/100 g/min, with corresponding OEFs of 30.9 ± 3.4%, 30.0 ± 1.8%, and 40.9 ± 2.4% for methods based on QSM, qBOLD, and QSM+qBOLD, respectively. QSM+qBOLD provided the highest CMRO 2 contrast between gray and white matter, more uniform OEF than QSM, and less noisy OEF than qBOLD. Quantitative CMRO 2 mapping that fits the entire complex GRE data is feasible by combining QSM analysis of phase and qBOLD analysis of magnitude. © 2018 International Society for Magnetic Resonance in Medicine.

  11. Single-cell measurement of red blood cell oxygen affinity.

    Science.gov (United States)

    Di Caprio, Giuseppe; Stokes, Chris; Higgins, John M; Schonbrun, Ethan

    2015-08-11

    Oxygen is transported throughout the body by hemoglobin (Hb) in red blood cells (RBCs). Although the oxygen affinity of blood is well-understood and routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of RBC volume and Hb concentration are taken millions of times per day by clinical hematology analyzers, and they are important factors in determining the health of the hematologic system. To better understand the variability and determinants of oxygen affinity on a cellular level, we have developed a system that quantifies the oxygen saturation, cell volume, and Hb concentration for individual RBCs in high throughput. We find that the variability in single-cell saturation peaks at an oxygen partial pressure of 2.9%, which corresponds to the maximum slope of the oxygen-Hb dissociation curve. In addition, single-cell oxygen affinity is positively correlated with Hb concentration but independent of osmolarity, which suggests variation in the Hb to 2,3-diphosphoglycerate (2-3 DPG) ratio on a cellular level. By quantifying the functional behavior of a cellular population, our system adds a dimension to blood cell analysis and other measurements of single-cell variability.

  12. The experimental study of oxygen contrast MR ventilation imaging

    International Nuclear Information System (INIS)

    Yang Jian; Guo Youmin; Wu Xiaoming; Xi Nong; Wang Jianguo; Zhu Li; Lei Xiaoyan; Xie Enyi

    2003-01-01

    Objective: To study the feasibility and basic technology of the oxygen contrast MR ventilation imaging in lung. Methods: Six canine lungs were scanned by using inversion recovery pulse sequence with turbo spin echo acquisition before and after inhalation of the 100% oxygen as T 1 contrast agent, and the T 1 values were measured. The contrast-to-noise ratio (CNR) for each inversion recovery time was compared and the relationship between arterial blood oxygen pressure (PaO 2 ) and T 1 relaxation rate was observed. Subtraction technique was employed in the postprocessing of pre- and post-oxygen conditions. Results: Molecular oxygen could shorten the pulmonary T 1 value (average 13.37%, t=2.683, P 1 value of pre- and post-oxygen conditions. The relaxtivity of T 1 resulted in excellent linear correlation (r 2 =0.9974) with PaO 2 . Through the subtraction of pre- and post-oxygen image, the oxygen contrast MR ventilation -image was obtained. Conclusion: The oxygen contrast MR ventilation imaging has the feasibility and clinical potential for the assessment of regional pulmonary function

  13. Therapeutic effect of forearm low level light treatment on blood flow, oxygenation, and oxygen consumption

    Science.gov (United States)

    Wang, Pengbo; Sun, Jiajing; Meng, Lingkang; Li, Zebin; Li, Ting

    2018-02-01

    Low level light/laser therapy (LLLT) is considered as a novel, non-invasive, and potential therapy in a variety of psychological and physical conditions, due to its effective intricate photobiomodulation. The mechanism of LLLT is that when cells are stimulated by photons, mitochondria produce a large quantity of ATP, which accelerates biochemical responses in the cell. It is of great significance to gain a clear insight into the change or interplay of various physiological parameters. In this study, we used functional near-infrared spectroscopy (fNIRS) and venous-occlusion plethysmography to measure the LLLT-induced changes in blood flow, oxygenation, and oxygen consumption in human forearms in vivo. Six healthy human participants (4 males and 2 females) were administered with 810-nm light emitted by LED array in ten minutes and blood flow, oxygenation and oxygen consumption were detected in the entire experiment. We found that LLLT induced an increase of blood flow and oxygen consumption on the treated site. Meanwhile, LLLT took a good role in promoting oxygenation of regional tissue, which was indicated by a significant increase of oxygenated hemoglobin concentration (Δ[HbO2]), a nearly invariable deoxygenated hemoglobin concentration (Δ[Hb]) and a increase of differential hemoglobin concentration (Δ[HbD] = Δ[HbO2] - Δ[Hb]). These results not only demonstrate enormous potential of LLLT, but help to figure out mechanisms of photobiomodulation.

  14. Blood oxygen level dependent magnetic resonance imaging for detecting pathological patterns in lupus nephritis patients: a preliminary study using a decision tree model.

    Science.gov (United States)

    Shi, Huilan; Jia, Junya; Li, Dong; Wei, Li; Shang, Wenya; Zheng, Zhenfeng

    2018-02-09

    Precise renal histopathological diagnosis will guide therapy strategy in patients with lupus nephritis. Blood oxygen level dependent (BOLD) magnetic resonance imaging (MRI) has been applicable noninvasive technique in renal disease. This current study was performed to explore whether BOLD MRI could contribute to diagnose renal pathological pattern. Adult patients with lupus nephritis renal pathological diagnosis were recruited for this study. Renal biopsy tissues were assessed based on the lupus nephritis ISN/RPS 2003 classification. The Blood oxygen level dependent magnetic resonance imaging (BOLD-MRI) was used to obtain functional magnetic resonance parameter, R2* values. Several functions of R2* values were calculated and used to construct algorithmic models for renal pathological patterns. In addition, the algorithmic models were compared as to their diagnostic capability. Both Histopathology and BOLD MRI were used to examine a total of twelve patients. Renal pathological patterns included five classes III (including 3 as class III + V) and seven classes IV (including 4 as class IV + V). Three algorithmic models, including decision tree, line discriminant, and logistic regression, were constructed to distinguish the renal pathological pattern of class III and class IV. The sensitivity of the decision tree model was better than that of the line discriminant model (71.87% vs 59.48%, P decision tree model was equivalent to that of the line discriminant model (63.87% vs 63.73%, P = 0.939) and higher than that of the logistic regression model (63.87% vs 38.0%, P decision tree model was greater than that of the line discriminant model (0.765 vs 0.629, P Decision tree models constructed using functions of R2* values may facilitate the prediction of renal pathological patterns.

  15. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level-Dependent Resting State Functional Connectivity.

    Science.gov (United States)

    Carhart-Harris, Robin L; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B; Ferguson, Bart; Williams, Luke T J; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A P; Williams, Tim M; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D; Feilding, Amanda; Curran, H Val; Nutt, David J

    2015-10-15

    The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level-dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug's characteristic subjective effects arise from its modulation of spontaneous brain activity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  16. Neonatal oxidative stress depends on oxygen blood pressure in umbilical artery.

    Science.gov (United States)

    Proietti, F; De Bernardo, G; Longini, M; Sordino, D; Scaramuzzini, G; Tataranno, M L; Belvisi, E; Bazzini, F; Perrone, S; Buonocore, G

    2016-01-01

    With advancing gestation, partial pressure of oxygen (pO2) and pH fall significantly. Hypoxia is a main factor inducing free radical generation and thereby oxidative stress (OS). Placental and fetal tissue response when oxygen becomes restricted is complex and partially known. We tested the hypothesis that changes in umbilical artery and vein blood gas concentrations modulate OS occurrence in the newborn. Seventy umbilical artery and vein plasma samples were collected from healthy term newborns immediately after delivery. F2 Isoprostanes (F2-Isop) were measured in all samples as reliable markers of lipid peroxidation. Significantly lower pCO2 and higher pO2 and pH were found in umbilical vein than in artery, as expected. A positive correlation was detected between pH and pO2 only in umbilical artery (p=0.019). F2-Isop levels were no different between artery and vein in cord blood. Significant correlations were found between F2-Isop and pCO2 (p=0.025) as well as between F2-Isop and pH in umbilical vein (p=0.027). F2-Isop correlated with pCO2 (p=0.007) as well as with pO2 values (p=0.005) in umbilical artery blood. Oxidative stress (OS) in newborns depends on oxygen concentrations in umbilical artery. OS biomarkers significantly correlate with pO2 and in umbilical artery but not in umbilical vein. In normoxic conditions fetal-maternal gas exchanges occurring in placenta re-establish normal higher oxygen levels in umbilical vein than artery, with a normal production of free radicals without any deleterious effects.

  17. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats.

    Science.gov (United States)

    Zafrani, Lara; Ergin, Bulent; Kapucu, Aysegul; Ince, Can

    2016-12-20

    The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Twenty-seven Wistar albino rats were randomized into four groups: a sham group (n = 6), a lipopolysaccharide (LPS) group (n = 7), a LPS group that received fluid resuscitation (n = 7), and a LPS group that received blood transfusion (n = 7). The mean arterial blood pressure, renal blood flow, and renal microvascular oxygenation within the kidney cortex were recorded. Acute kidney injury was assessed using the serum creatinine levels, metabolic cost, and histopathological lesions. Nitrosative stress (expression of endothelial (eNOS) and inducible nitric oxide synthase (iNOS)) within the kidney was assessed by immunohistochemistry. Hemoglobin levels, pH, serum lactate levels, and liver enzymes were measured. Fluid resuscitation and blood transfusion both significantly improved the mean arterial pressure and renal blood flow after LPS infusion. Renal microvascular oxygenation, serum creatinine levels, and tubular damage significantly improved in the LPS group that received blood transfusion compared to the group that received fluids. Moreover, the renal expression of eNOS was markedly suppressed under endotoxin challenge. Blood transfusion, but not fluid resuscitation, was able to restore the renal expression of eNOS. However, there were no significant differences in lactic acidosis or liver function between the two groups. Blood transfusion significantly improved renal function in endotoxemic rats. The specific beneficial effect of blood transfusion on the kidney could have been mediated in part by the improvements in renal microvascular oxygenation and sepsis-induced endothelial dysfunction via the restoration of eNOS expression within the kidney.

  18. Assessment of early renal allograft dysfunction with blood oxygenation level-dependent MRI and diffusion-weighted imaging

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sung Yoon [Department of Radiology and Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of); Kim, Chan Kyo, E-mail: chankyokim@skku.edu [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Park, Byung Kwan [Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Kim, Sung Ju; Lee, Sanghoon [Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of); Huh, Wooseong [Department of Nephrology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

    2014-12-15

    Highlights: • R2* and ADC in renal allografts are moderately correlated with eGFR. • R2* and ADC are lower in early allograft dysfunction than normal allograft function. • No significant difference between AR and ATN was found in both R2* and ADC. - Abstract: Purpose: To investigate blood oxygenation level-dependent (BOLD) MRI and diffusion-weighted imaging (DWI) at 3 T for assessment of early renal allograft dysfunction. Materials and methods: 34 patients with a renal allograft (early dysfunction, 24; normal, 10) were prospectively enrolled. BOLD MRI and DWI were performed at 3 T. R2* and apparent diffusion coefficient (ADC) values were measured in cortex and medulla of the allografts. Correlation between R2* or ADC values and estimated glomerular filtration rate (eGFR) was investigated. R2* or ADC values were compared among acute rejection (AR), acute tubular necrosis (ATN) and normal function. Results: In all renal allografts, cortical or medullary R2* and ADC values were moderately correlated with eGFR (P < 0.05). Early dysfunction group showed lower R2* and ADC values than normal function group (P < 0.05). AR or ATN had lower R2* values than normal allografts (P < 0.05), and ARs had lower cortical ADC values than normal allografts (P < 0.05). No significant difference of R2* or ADC values was found between AR and ATN (P > 0.05). Conclusion: BOLD MRI and DWI at 3 T may demonstrate early functional state of renal allografts, but may be limited in characterizing a cause of early renal allograft dysfunction. Further studies are needed.

  19. Single-cell measurement of red blood cell oxygen affinity

    OpenAIRE

    Caprio, Di; Stokes, Chris; Higgins, John M.; Schonbrun, Ethan

    2015-01-01

    Oxygen is transported throughout the body by hemoglobin in red blood cells. While the oxygen affinity of blood is well understood and is routinely assessed in patients by pulse oximetry, variability at the single-cell level has not been previously measured. In contrast, single-cell measurements of red blood cell volume and hemoglobin concentration are taken millions of times per day by clinical hematology analyzers and are important factors in determining the health of the hematologic system....

  20. Investigating Functional Extension of Optical Coherence Tomography for Spectroscopic Analysis of Blood Oxygen Saturation

    Science.gov (United States)

    Chen, Siyu

    Over the past two decades, optical coherence tomography (OCT) has been successfully applied to various fields of biomedical researching and clinical studies, including cardiology, urology, dermatology, dentistry, oncology, and most successfully, ophthalmology. This dissertation seeks to extend the current OCT practice, which is still largely morphology-based, into a new dimension, functional analysis of metabolic activities in vivo. More specifically, the investigation is focused on retrieving blood oxygen saturation (sO2) using intrinsic hemoglobin optical absorption contrast. Most mammalian cells rely on aerobic respiration to support cellular function, which means they consume oxygen to create adenosine triphosphate (ATP). Metabolic rate of oxygen (MRO2), a key hemodynamic parameter, characterizes how much oxygen is consumed during a given period of time, reflecting the metabolic activity of the target tissue. For example, retinal neurons are highly active and almost entirely rely on the moment-to-moment oxygen supply from retinal circulations. Thus, variation in MRO2 reveals the instantaneous activity of these neurons, shedding light on the physiological and pathophysiological change of cellular functions. Eventually, measuring MRO2 can potentially provide a biomarker for early-stage disease diagnosis, and serve as one benchmark for evaluating effectiveness of medical intervention during disease management. Essential in calculating MRO2, blood sO2 measurements using spectroscopic OCT analysis has been attempted as early as 2003. OCT is intrinsically sensitive to the blood optical absorption spectrum due to its wide-band illumination and detection scheme relying on back-scattered photon. However, accurate retrieval of blood sO2 using conventional near infrared (NIR) OCT systems in vivo has remained challenging. It was not until the development of OCT systems using visible light illumination (vis-OCT) when accurate measurement of blood sO2 was reported in live

  1. Application of language blood oxygenation level dependent functional MRI in the navigating operation of neurosurgery

    International Nuclear Information System (INIS)

    Liu Shuyong; Li Min; Yao Chengjun; Geng Daoying

    2011-01-01

    Objective: To verify the accuracy of blood oxygenation level dependent (BOLD)-based activation using electrocortical stimulation mapping (ESM) and explore the value of language fMRI in the navigating operation of neurosurgery. Methods: In 8 cases with brain tumors, BOLD-fMRI examinations were done before the operations. Under the state of awake anesthesia,the patients were aroused and ESM was conducted. Point-to-point comparison between the BOLD signal activations and the ESM was carried out under the surveillance of the neuro-navigation technology. In order to observe the sensibility and specificity of BOLD activations, the location of BOLD activations and the point of ESM was compared to calculate the stimulating positive points inside the regions of BOLD signals (real positive), outside BOLD regions (pseudo- negative), the stimulating negative points inside the regions of BOLD signals (pseudo-positive), and outside BOLD region (real negative). Two kinds of criteria for assessment were used. One was that the positive stimulating points were located in BOLD regions, and the other was that the positive stimulating points were located within 1 cm around the range of BOLD regions. Removal of the lesions were conducted with the tissue 1 cm around the language region preserved, and the cortex inside 0.5-1.0 cm distance from the positive points were retained. Results: Of the 8 cases, only 6 finished the tasks. Among them, 3 cases were with astrocytoma of grade 2, 2 were with astrocytoma of grade 3, and one with glioblastoma. The total number of stimulating points was 48, among which the positive points were 11. When the first criteria was applied, the sensitivity was 72.7% (8/11), and the specificity was 81.8% (30/37). When the second criteria was applied, the sensitivity was 82.0% (9/11), and the specificity was 75.6% (28/37). Follow-up after operation showed no aphasia occurred. Conclusions: BOLD-fMRI had a high sensitivity and specificity in displaying the language

  2. Blood oxygenation level dependent functional MRI study on the changes of motor cortex in patients with amyotrophic lateral sclerosis

    International Nuclear Information System (INIS)

    Han Jing; Ma Lin; Lou Xin; Yu Shengyuan; Li Dejun

    2008-01-01

    Objective: To study the changes of motor cortex in patients with amyotrophic lateral sclerosis (ALS) while executing sequential finger tapping movement by using blood oxygenation level dependent (BOLD) functional MRI. Methods: Fifteen patients with definite or probable ALS and 15 age and gender matched normal controls were enrolled in the BOLD study, and all the subjects were right-handed with no other diseases or any recent medication history. A 3.0 T MR scanner' was employed and gradient echo EPI (GRE-EPI)sequence was used to acquire the functional images. Subjects executed sequential finger tapping movement at a frequency of 1-2 Hz during a block design task. fMRI data were analyzed by using statistical parametric mapping (SPM) 2. Volume of activated brain areas was compared with the use of a Student's t-test. Results: Bilateral primary sensorimotor cortex (PSM), bilateral posterior aspect of premotor area (PA), bilateral supplementary motor area (SMA), contralateral inferior lateral premotor area (ILPA), bilateral parietal region (PAR), and ipsilateral cerebellum showed activation in both ALS patients and normal controls when executing the same motor task. The activation areas in bilateral PSM and bilateral posterior aspect of PA ( right hand ipsilateral activation: ALS (924.5±141.1) mm 3 , control (829.9± 98.4) mm 3 , P=0.05; right hand contralateral activation: ALS (9143.8±702.8) mm 3 , control (8638.8±506.4) mm 3 P 3 , control (902.5±3 184.2)mm , P 3 , control (5934.6±616.4) mm 3 , P 3 , control (4710.7±416.3) mm 3 , P 3 , control (3688.9±672.3) mm 3 , P 3 , control (254.3±84.4) mm 3 , P 3 , control (1689.0±719.6) mm 3 , P<0.05) were significantly larger in ALS patients than in normal controls. Extra activation areas including ipsilateral ILPA, contralateral cerebellum and bilateral posterior limb of internal capsule were only detected in ALS patients. Conclusions: Similar activation areas were seen in both groups while executing the same motor

  3. Hemoglobin Function in Stored Blood.

    Science.gov (United States)

    1974-08-01

    States during 1973. Several advantages over ACA) are important. Blood stored in CPD maintains higher ./ levels of 2,3-DPG (2,3- diphosphoglycerate ) and a...survival and ATP levels in stored blood is explained by the several functions of ATP which are necessary for cell viability. However, ATP levels do...not correlate with oxygen affinity during storage. Levels of 2,3-DPG determine oxygen affinity and thus hemoglobin function. (12,13) When normal levels

  4. Time-Dependent Behavior of Microvascular Blood Flow and Oxygenation: A Predictor of Functional Outcomes.

    Science.gov (United States)

    Kuliga, Katarzyna Z; Gush, Rodney; Clough, Geraldine F; Chipperfield, Andrew John

    2018-05-01

    This study investigates the time-dependent behaviour and algorithmic complexity of low-frequency periodic oscillations in blood flux (BF) and oxygenation signals from the microvasculature. Microvascular BF and oxygenation (OXY: oxyHb, deoxyHb, totalHb, and SO 2 %) was recorded from 15 healthy young adult males using combined laser Doppler fluximetry and white light spectroscopy with local skin temperature clamped to 33  °C and during local thermal hyperaemia (LTH) at 43 °C. Power spectral density of the BF and OXY signals was evaluated within the frequency range (0.0095-1.6 Hz). Signal complexity was determined using the Lempel-Ziv (LZ) algorithm. Fold increase in BF during LTH was 15.6 (10.3, 22.8) and in OxyHb 4.8 (3.5, 5.9) (median, range). All BF and OXY signals exhibited multiple oscillatory components with clear differences in signal power distribution across frequency bands at 33 and 43 °C. Significant reduction in the intrinsic variability and complexity of the microvascular signals during LTH was found, with mean LZ complexity of BF and OxyHb falling by 25% and 49%, respectively ( ). These results provide corroboration that in human skin microvascular blood flow and oxygenation are influenced by multiple time-varying oscillators that adapt to local influences and become more predictable during increased haemodynamic flow. Recent evidence strongly suggests that the inability of microvascular networks to adapt to an imposed stressor is symptomatic of disease risk which might be assessed via BF and OXY via the combination signal analysis techniques described here.

  5. Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging.

    Science.gov (United States)

    Niles, David J; Artz, Nathan S; Djamali, Arjang; Sadowski, Elizabeth A; Grist, Thomas M; Fain, Sean B

    2016-02-01

    The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients. The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment. In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P donors, and they indicate a potentially beneficial effect of losartan in recipients.

  6. Effects of Intensified Vasodilatory Antihypertensive Treatment on Renal Function, Blood supply and Oxygenation in Chronic Kidney Disease

    DEFF Research Database (Denmark)

    Khatir, Dinah Sherzad; Pedersen, Michael; Ivarsen, Per

    2015-01-01

    -blocker metoprolol). At baseline and following 18 months of therapy we determined forearm resistance by venous occlusion plethysmography. Using magnetic resonance imaging (MRI) renal artery blood flow was measured for calculation of RVR, and blood oxygen level dependent (BOLD) MRI was used as a marker of renal...

  7. Skin Blood Perfusion and Oxygenation Colour Affect Perceived Human Health

    Science.gov (United States)

    Stephen, Ian D.; Coetzee, Vinet; Law Smith, Miriam; Perrett, David I.

    2009-01-01

    Skin blood perfusion and oxygenation depends upon cardiovascular, hormonal and circulatory health in humans and provides socio-sexual signals of underlying physiology, dominance and reproductive status in some primates. We allowed participants to manipulate colour calibrated facial photographs along empirically-measured oxygenated and deoxygenated blood colour axes both separately and simultaneously, to optimise healthy appearance. Participants increased skin blood colour, particularly oxygenated, above basal levels to optimise healthy appearance. We show, therefore, that skin blood perfusion and oxygenation influence perceived health in a way that may be important to mate choice. PMID:19337378

  8. Large arteriolar component of oxygen delivery implies a safe margin of oxygen supply to cerebral tissue.

    Science.gov (United States)

    Sakadžić, Sava; Mandeville, Emiri T; Gagnon, Louis; Musacchia, Joseph J; Yaseen, Mohammad A; Yucel, Meryem A; Lefebvre, Joel; Lesage, Frédéric; Dale, Anders M; Eikermann-Haerter, Katharina; Ayata, Cenk; Srinivasan, Vivek J; Lo, Eng H; Devor, Anna; Boas, David A

    2014-12-08

    What is the organization of cerebral microvascular oxygenation and morphology that allows adequate tissue oxygenation at different activity levels? We address this question in the mouse cerebral cortex using microscopic imaging of intravascular O2 partial pressure and blood flow combined with numerical modelling. Here we show that parenchymal arterioles are responsible for 50% of the extracted O2 at baseline activity, and the majority of the remaining O2 exchange takes place within the first few capillary branches. Most capillaries release little O2 at baseline acting as an O2 reserve that is recruited during increased neuronal activity or decreased blood flow. Our results challenge the common perception that capillaries are the major site of O2 delivery to cerebral tissue. The understanding of oxygenation distribution along arterio-capillary paths may have profound implications for the interpretation of blood-oxygen-level dependent (BOLD) contrast in functional magnetic resonance imaging and for evaluating microvascular O2 delivery capacity to support cerebral tissue in disease.

  9. Navigator-gated 3D blood oxygen level-dependent CMR at 3.0-T for detection of stress-induced myocardial ischemic reactions.

    Science.gov (United States)

    Jahnke, Cosima; Gebker, Rolf; Manka, Robert; Schnackenburg, Bernhard; Fleck, Eckart; Paetsch, Ingo

    2010-04-01

    This study determined the value of navigator-gated 3-dimensional blood oxygen level-dependent (BOLD) cardiac magnetic resonance (CMR) at 3.0-T for the detection of stress-induced myocardial ischemic reactions. Although BOLD CMR has been introduced for characterization of myocardial oxygenation status, previously reported CMR approaches suffered from a low signal-to-noise ratio and motion-related artifacts with impaired image quality and a limited diagnostic value in initial patient studies. Fifty patients with suspected or known coronary artery disease underwent CMR at 3.0-T followed by invasive X-ray angiography within 48 h. Three-dimensional BOLD images were acquired during free breathing with full coverage of the left ventricle in a short-axis orientation. The BOLD imaging was performed at rest and under adenosine stress, followed by stress and rest first-pass perfusion and delayed enhancement imaging. Quantitative coronary X-ray angiography (QCA) was used for coronary stenosis definition (diameter reduction > or =50%). The BOLD and first-pass perfusion images were semiquantitatively evaluated (for BOLD imaging, signal intensity differences between stress and rest [DeltaSI]; for perfusion imaging, myocardial perfusion reserve index [MPRI]). The image quality of BOLD CMR at rest and during adenosine stress was considered good to excellent in 90% and 84% of the patients, respectively. The DeltaSI measurements differed significantly between normal myocardium, myocardium supplied by a stenotic coronary artery, and infarcted myocardium (p exogenous contrast-enhancement studies. Copyright 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  10. Cerebrovascular blood oxygenation level dependent pulsatility at baseline and following acute exercise among healthy adolescents.

    Science.gov (United States)

    Theyers, Athena E; Goldstein, Benjamin I; Metcalfe, Arron Ws; Robertson, Andrew D; MacIntosh, Bradley J

    2018-01-01

    Arterial stiffness is linked to cerebral small vessel damage and neurodegeneration, but barriers to accessing deep cerebrovascular anatomy limit our ability to assess the brain. This study describes an adaptation of a cardiac-related scrubbing method as a means of generating blood oxygenation level-dependent pulsatility maps based on the cardiac cycle. We examine BOLD pulsatility at rest, based on the non-parametric deviation from null metric, as well as changes following acute physiological stress from 20 min of moderate-intensity cycling in 45 healthy adolescents. We evaluate the influence of repetition time (TR) and echo time (TE) using simulated and multi-echo empirical data, respectively. There were tissue-specific and voxel-wise BOLD pulsatility decreases 20 min following exercise cessation. BOLD pulsatility detection was comparable over a range of TR and TE values when scan volumes were kept constant; however, short TRs (≤500 ms) and TEs (∼14 ms) acquisitions would yield the most efficient detection. Results suggest cardiac-related BOLD pulsatility may represent a robust and easily adopted method of mapping cerebrovascular pulsatility with voxel-wise resolution.

  11. Evaluation of Renal Blood Flow and Oxygenation in CKD Using Magnetic Resonance Imaging.

    Science.gov (United States)

    Khatir, Dinah S; Pedersen, Michael; Jespersen, Bente; Buus, Niels H

    2015-09-01

    Animal studies suggest that progression of chronic kidney disease (CKD) is related to renal hypoxia. With renal blood supply determining oxygen delivery and sodium absorption being the main contributor to oxygen consumption, we describe the relationship between renal oxygenation, renal artery blood flow, and sodium absorption in patients with CKD and healthy controls. Cross-sectional study. 62 stable patients with CKD stages 3 to 4 (mean age, 61±13 [SD] years) and 24 age- and sex-matched controls. CKD versus control status. Renal artery blood flow, tissue oxygenation (relative changes in deoxyhemoglobin concentration of the renal medulla [MR2*] and cortex [CR2*]), and sodium absorption. Renal artery blood flow was determined by phase-contrast magnetic resonance imaging (MRI); MR2* and CR2* were determined by blood oxygen level-dependent MRI. Ultrafiltered and reabsorbed sodium were determined from measured glomerular filtration rate (mGFR) and 24-hour urine collections. mGFR in patients was 37% that of controls (36±15 vs 97±23 mL/min/1.73 m(2); P renal artery blood flow was 72% that of controls (319 vs 443 mL/min; P renal artery blood flow or sodium absorption. Increasing arterial blood oxygen tension by breathing 100% oxygen had very small effects on CR2*, but reduced MR2* in both groups. Only renal artery blood flow was determined and thus regional perfusion could not be related to CR2* or MR2*. In CKD, reductions of mGFR and reabsorbed sodium are more than double that of renal artery blood flow, whereas cortical and medullary oxygenation are within the range of healthy persons. Reduction in glomerular filtration fraction may prevent renal hypoxia in CKD. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  12. Blood oxygen level-dependent magnetic resonance imaging for detecting pathological patterns in patients with lupus nephritis: a preliminary study using gray-level co-occurrence matrix analysis.

    Science.gov (United States)

    Shi, Huilan; Jia, Junya; Li, Dong; Wei, Li; Shang, Wenya; Zheng, Zhenfeng

    2018-01-01

    Objective Blood oxygen level-dependent magnetic resonance imaging (BOLD MRI) is a noninvasive technique useful in patients with renal disease. The current study was performed to determine whether BOLD MRI can contribute to the diagnosis of renal pathological patterns. Methods BOLD MRI was used to obtain functional magnetic resonance parameter R2* values. Gray-level co-occurrence matrixes (GLCMs) were generated for gray-scale maps. Several GLCM parameters were calculated and used to construct algorithmic models for renal pathological patterns. Results Histopathology and BOLD MRI were used to examine 12 patients. Two GLCM parameters, including correlation and energy, revealed differences among four groups of renal pathological patterns. Four Fisher's linear discriminant formulas were constructed using two variables, including the correlation at 45° and correlation at 90°. A cross-validation test showed that the formulas correctly predicted 28 of 36 samples, and the rate of correct prediction was 77.8%. Conclusions Differences in the texture characteristics of BOLD MRI in patients with lupus nephritis may be detected by GLCM analysis. Discriminant formulas constructed using GLCM parameters may facilitate prediction of renal pathological patterns.

  13. A blood-oxygenation-dependent increase in blood viscosity due to a static magnetic field

    International Nuclear Information System (INIS)

    Yamamoto, Toru; Nagayama, Yuki; Tamura, Mamoru

    2004-01-01

    As the magnetic field of widely used MR scanners is one of the strongest magnetic fields to which people are exposed, the biological influence of the static magnetic field of MR scanners is of great concern. One magnetic interaction in biological subjects is the magnetic torque on the magnetic moment induced by biomagnetic substances. The red blood cell is a major biomagnetic substance, and the blood flow may be influenced by the magnetic field. However, the underlying mechanisms have been poorly understood. To examine the mechanisms of the magnetic influence on blood viscosity, we measured the time for blood to fall through a glass capillary inside and outside a 1.5 T MR scanner. Our in vitro results showed that the blood viscosity significantly increased in a 1.5 T MR scanner, and also clarified the mechanism of the interaction between red blood cells and the external magnetic field. Notably, the blood viscosity increased depending on blood oxygenation and the shear rate of the blood flow. Thus, our findings suggest that even a 1.5 T magnetic field may modulate blood flow

  14. Staging Hemodynamic Failure With Blood Oxygen-Level-Dependent Functional Magnetic Resonance Imaging Cerebrovascular Reactivity: A Comparison Versus Gold Standard (15O-)H2O-Positron Emission Tomography.

    Science.gov (United States)

    Fierstra, Jorn; van Niftrik, Christiaan; Warnock, Geoffrey; Wegener, Susanne; Piccirelli, Marco; Pangalu, Athina; Esposito, Giuseppe; Valavanis, Antonios; Buck, Alfred; Luft, Andreas; Bozinov, Oliver; Regli, Luca

    2018-03-01

    Increased stroke risk correlates with hemodynamic failure, which can be assessed with ( 15 O-)H 2 O positron emission tomography (PET) cerebral blood flow (CBF) measurements. This gold standard technique, however, is not established for routine clinical imaging. Standardized blood oxygen-level-dependent (BOLD) functional magnetic resonance imaging+CO 2 is a noninvasive and potentially widely applicable tool to assess whole-brain quantitative cerebrovascular reactivity (CVR). We examined the agreement between the 2 imaging modalities and hypothesized that quantitative CVR can be a surrogate imaging marker to assess hemodynamic failure. Nineteen data sets of subjects with chronic cerebrovascular steno-occlusive disease (age, 60±11 years; 4 women) and unilaterally impaired perfusion reserve on Diamox-challenged ( 15 O-)H 2 O PET were studied and compared with a standardized BOLD functional magnetic resonance imaging+CO 2 examination within 6 weeks (8±19 days). Agreement between quantitative CBF- and CVR-based perfusion reserve was assessed. Hemodynamic failure was staged according to PET findings: stage 0: normal CBF, normal perfusion reserve; stage I: normal CBF, decreased perfusion reserve; and stage II: decreased CBF, decreased perfusion reserve. The BOLD CVR data set of the same subjects was then matched to the corresponding stage of hemodynamic failure. PET-based stage I versus stage II could also be clearly separated with BOLD CVR measurements (CVR for stage I 0.11 versus CVR for stage II -0.03; P the affected hemisphere and middle cerebral artery territory ( P the affected hemisphere and middle cerebral artery territory and for identifying hemodynamic failure stage II. BOLD CVR may, therefore, be considered for prospective studies assessing stroke risk in patients with chronic cerebrovascular steno-occlusive disease, in particular because it can potentially be implemented in routine clinical imaging. © 2018 American Heart Association, Inc.

  15. Limitations of quantitative photoacoustic measurements of blood oxygenation in small vessels

    International Nuclear Information System (INIS)

    Sivaramakrishnan, Mathangi; Maslov, Konstantin; Zhang, Hao F; Stoica, George; Wang, Lihong V

    2007-01-01

    We investigate the feasibility of obtaining accurate quantitative information, such as local blood oxygenation level (sO 2 ), with a spatial resolution of about 50 μm from spectral photoacoustic (PA) measurements. The optical wavelength dependence of the peak values of the PA signals is utilized to obtain the local blood oxygenation level. In our in vitro experimental models, the PA signal amplitude is found to be linearly proportional to the blood optical absorption coefficient when using ultrasonic transducers with central frequencies high enough such that the ultrasonic wavelengths are shorter than the light penetration depth into the blood vessels. For an optical wavelength in the 578-596 nm region, with a transducer central frequency that is above 25 MHz, the sensitivity and accuracy of sO 2 inversion is shown to be better than 4%. The effect of the transducer focal position on the accuracy of quantifying blood oxygenation is found to be negligible. In vivo oxygenation measurements of rat skin microvasculature yield results consistent with those from in vitro studies, although factors specific to in vivo measurements, such as the spectral dependence of tissue optical attenuation, dramatically affect the accuracy of sO 2 quantification in vivo

  16. Quantification of modulated blood oxygenation levels in single cerebral veins by investigating their MR signal decay

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan [St. Jude Children' s Research Hospital, Memphis, TN (United States). Div. of Translational Imaging Research; University Clinics Jena (Germany). Medical Physics Group; Rauscher, Alexander [University Clinics Jena (Germany). Medical Physics Group; British Columbia Univ., Vancouver (Canada). MRI Research Centre; Reichenbach, Juergen R. [University Clinics Jena (Germany). Medical Physics Group

    2009-07-01

    The transverse magnetization of a single vein and its surrounding tissue is subject to spin dephasing caused by the local magnetic field inhomogeneity which is induced by the very same vessel. This phenomenon can be approximated and simulated by applying the model of an infinitely long and homogeneously magnetized cylinder embedded in a homogeneous tissue background. It is then possible to estimate the oxygenation level of the venous blood by fitting the simulated magnetization-time-course to the measured signal decay. In this work we demonstrate the ability of this approach to quantify the blood oxygenation level (Y) of small cerebral veins in vivo, not only under normal physiologic conditions (Y{sub native}=0.5-0.55) but also during induced changes of physiologic conditions which affect the cerebral venous blood oxygenation level. Changes of blood's oxygenation level induced by carbogen (5% CO{sub 2}, 95% O{sub 2}) and caffeine were observed and quantified, resulting in values of Y{sub carbogen}=0.7 and Y{sub caffeine}=0.42, respectively. The proposed technique may ultimately help to better understand local changes in cerebral physiology during neuronal activation by quantifying blood oxygenation in veins draining active brain areas. It may also be beneficial in clinical applications where it may improve diagnosis of cerebral pathologies as well as monitoring of responses to therapy. (orig.)

  17. Relationship between systemic hemodynamics and ambulatory blood pressure level are sex dependent.

    Science.gov (United States)

    Alfie, J; Waisman, G D; Galarza, C R; Magi, M I; Vasvari, F; Mayorga, L M; Cámera, M I

    1995-12-01

    Sex-related differences in systemic hemodynamics were analyzed by means of cardiac index and systemic vascular resistance according to the level of daytime ambulatory blood pressure. In addition, we assessed the relations between ambulatory blood pressure measurements and systemic hemodynamics in male and female patients. We prospectively included 52 women and 53 men referred to our unit for evaluation of arterial hypertension. Women and men were grouped according to the level of daytime mean arterial pressure: or = 110 mm Hg. Patients underwent noninvasive evaluation of resting hemodynamics (impedance cardiography) and 24-hour ambulatory blood pressure monitoring. Compared with women men with lower daytime blood pressure had a 12% higher systemic vascular resistance index (P = NS) and a 14% lower cardiac index (P < .02), whereas men with higher daytime blood pressure had a 25% higher vascular resistance (P < .003) and a 21% lower cardiac index (P < .0004). Furthermore, in men systemic vascular resistance correlated positively with both daytime and nighttime systolic and diastolic blood pressures, whereas cardiac index correlated negatively only with daytime diastolic blood pressure. In contrast, women did not exhibit any significant correlation between hemodynamic parameters and ambulatory blood pressure measurements. In conclusion, sex-related differences in systemic hemodynamics were more pronounced in the group with higher daytime hypertension. The relations between systemic hemodynamics and ambulatory blood pressure level depended on the sex of the patient. In men a progressive circulatory impairment underlies the increasing level of ambulatory blood pressure, but this was not observed in women.

  18. Origins of intersubject variability of blood oxygenation level dependent and arterial spin labeling fMRI: implications for quantification of brain activity.

    Science.gov (United States)

    Gaxiola-Valdez, Ismael; Goodyear, Bradley G

    2012-12-01

    Accurate localization of brain activity using blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has been challenged because of the large BOLD signal within distal veins. Arterial spin labeling (ASL) techniques offer greater sensitivity to the microvasculature but possess low temporal resolution and limited brain coverage. In this study, we show that the physiological origins of BOLD and ASL depend on whether percent change or statistical significance is being considered. For BOLD and ASL fMRI data collected during a simple unilateral hand movement task, we found that in the area of the contralateral motor cortex the centre of gravity (CoG) of the intersubject coefficient of variation (CV) of BOLD fMRI was near the brain surface for percent change in signal, whereas the CoG of the intersubject CV for Z-score was in close proximity of sites of brain activity for both BOLD and ASL. These findings suggest that intersubject variability of BOLD percent change is vascular in origin, whereas the origin of inter-subject variability of Z-score is neuronal for both BOLD and ASL. For longer duration tasks (12 s or greater), however, there was a significant correlation between BOLD and ASL percent change, which was not evident for short duration tasks (6 s). These findings suggest that analyses directly comparing percent change in BOLD signal between pre-defined regions of interest using short duration stimuli, as for example in event-related designs, may be heavily weighted by large-vessel responses rather than neuronal responses. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. The effect of glycerol on regional cerebral blood flow, blood volume and oxygen metabolism

    International Nuclear Information System (INIS)

    Ishikawa, Masatsune; Kikuchi, Haruhiko; Nagata, Izumi; Yamagata, Sen; Taki, Waro; Kobayashi, Akira; Yonekura, Yoshiharu; Nishizawa, Sadahiko.

    1989-01-01

    Using positron emission tomography with 15 O-labelled CO 2 , O 2 and CO gases, the effects of glycerol on regional cerebral blood flow (CBF), blood volume (CBV) and oxygen metabolism (CMRO 2 ) were investigated in 6 patients with meningioma accompanying peritumoral brain edema. The same study was done in 5 normal volunteers. The changes of blood gases, hematocrit and hemoglobin were also examined. After a drip infusion of glycerol, the regional CBF increased not only in the peritumoral cortex and white matter but also in the intact cortex and white matter on the contralateral side. The increase of CBF was extensive and substantially there were no regional differences. In contrast, the changes of CMRO 2 were not significant. This was derived from the increase in oxygen extraction fraction throughout extensive areas including the peritumoral area. There were no changes in CBV. Hematocrit and hemoglobin decreased to a small degree. In the normal volunteers, the same findings were noted. Thus, glycerol increases the functional reserve for cerebral oxygen metabolism, not only in the peritumoral regions but also in the intact regions. The effects of glycerol on hemodynamics and metabolism were discussed with reference to some differences from mannitol. (author)

  20. Assessment of cerebral blood flow reserve using blood oxygen level-dependent echo planar imaging after acetazolamide administration in patients post-STA-MCA anastomosis surgery

    International Nuclear Information System (INIS)

    Zenke, Kiichiro; Kusunoki, Katsusuke; Saito, Masahiro; Sadamoto, Kazuhiko; Ohta, Shinsuke; Kumon, Yoshiaki; Sakaki, Saburo; Nagasawa, Kiyoshi

    1998-01-01

    Recently, blood oxygen level-dependent (BOLD) echo planar imaging (EPI) has been used to estimate blood flow changes. Theoretically, a relative decrement of deoxyhemoglobin in cerebral blood supply induces a MR signal change after neuronal stimulation. In the present study, we have attempted to evaluate CBF reserve capacity by the BOLD EPI in patients who had undergone STA-MCA anastomosis surgery. Then, we compared with the signal intensity changes obtained by this procedure with the CBF changes by Xe-SPECT after acetazolamide administration. Six patients, post-STA-MCA anastomosis surgery, were studied. Pre-operatively, MR signal intensity and CBF, by Xe-SPECT, were increased in the intact side after acetazolamide administration in all patients, and MR signal intensities were decreased in low flow regions after acetazolamide administration in all four patients in whom so-called steal phenomenon was demonstrated by Xe-SPECT study. Post-operatively, poor response was shown after acetazolamide administration with both Xe-SPECT and BOLD EPI in the two patients who had unsuccessful anastomoses. In the successfully anastomosed patients, improved vascular reactivity was demonstrated on BOLD EPI after acetazolamide administration in 3 of 4 patients in whom an improvement of vascular reactivity was demonstrated on Xe-SPECT. In one patient, MRI studies were considered to have technical artifacts, because the MR signal intensity did not increase, even in the intact side after acetazolamide administration. In conclusion, BOLD EPI after acetazolamide administration is an useful procedure for the pre- and post-operative of vascular reserve in patients with ischemic stroke. (author)

  1. A comparison of blood nitric oxide metabolites and hemoglobin functional properties among diving mammals.

    Science.gov (United States)

    Fago, Angela; Parraga, Daniel Garcia; Petersen, Elin E; Kristensen, Niels; Giouri, Lea; Jensen, Frank B

    2017-03-01

    The ability of marine mammals to hunt prey at depth is known to rely on enhanced oxygen stores and on selective distribution of blood flow, but the molecular mechanisms regulating blood flow and oxygen transport remain unresolved. To investigate the molecular mechanisms that may be important in regulating blood flow, we measured concentration of nitrite and S-nitrosothiols (SNO), two metabolites of the vasodilator nitric oxide (NO), in the blood of 5 species of marine mammals differing in their dive duration: bottlenose dolphin, South American sea lion, harbor seal, walrus and beluga whale. We also examined oxygen affinity, sensitivity to 2,3-diphosphoglycerate (DPG) and nitrite reductase activity of the hemoglobin (Hb) to search for possible adaptive variations in these functional properties. We found levels of plasma and red blood cells nitrite similar to those reported for terrestrial mammals, but unusually high concentrations of red blood cell SNO in bottlenose dolphin, walrus and beluga whale, suggesting enhanced SNO-dependent signaling in these species. Purified Hbs showed similar functional properties in terms of oxygen affinity and sensitivity to DPG, indicating that reported large variations in blood oxygen affinity among diving mammals likely derive from phenotypic variations in red blood cell DPG levels. The nitrite reductase activities of the Hbs were overall slightly higher than that of human Hb, with the Hb of beluga whale, capable of longest dives, having the highest activity. Taken together, these results underscore adaptive variations in circulatory NO metabolism in diving mammals but not in the oxygenation properties of the Hb. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. СHANGES IN PARAMETERS OF LUMINOL-DEPENDENT AND LUCIGENIN-DEPENDENT CHEMILUMINESCENCE OF PERIPHERAL BLOOD NEUTROPHILS IN PATIENTS WITH BLADDER CANCER IN THE DISEASE DYNAMICS

    Directory of Open Access Journals (Sweden)

    L. M. Kurtasova

    2015-01-01

    Full Text Available The study deals with parameters of luminol-dependent and lucigenin-dependent chemiluminescence (CL of peripheral blood neutrophils from patients with bladder cancer (BC prior to surgical treatment. We examined sixty patients (45 to 55 years old with advanced bladder cancer (TNM prior to the operation, and forty-six patients at 10 days after surgical treatment. A control group consisted of 56 healthy donors. Luminol-dependent and lucigenin-dependent chemiluminescence of blood neutrophils was assessed according to De Sole et al. (1983. Chemiluminescence assays of peripheral blood neutrophils from the patients with bladder cancer revealed changes in production of reactive oxygen species (ROS, both for initial stage of oxidation reaction, and total level of active oxygen radicals. We have found disturbed values of primary-to-secondary ROS ratio in the cells. In the patients with bladder cancer, some changes in oxidative metabolism of the blood neutrophils have been registered. These alterations may play an important role in promotion of potential effector cell functions, thus, probably, affecting the whole-scale development of a cytopathic effect exerted by neutrophilic granulocytes. 

  3. The effects of transit time heterogeneity on brain oxygenation during rest and functional activation

    Science.gov (United States)

    Rasmussen, Peter M; Jespersen, Sune N; Østergaard, Leif

    2015-01-01

    The interpretation of regional blood flow and blood oxygenation changes during functional activation has evolved from the concept of ‘neurovascular coupling', and hence the regulation of arteriolar tone to meet metabolic demands. The efficacy of oxygen extraction was recently shown to depend on the heterogeneity of capillary flow patterns downstream. Existing compartment models of the relation between tissue metabolism, blood flow, and blood oxygenation, however, typically assume homogenous microvascular flow patterns. To take capillary flow heterogeneity into account, we modeled the effect of capillary transit time heterogeneity (CTH) on the ‘oxygen conductance' used in compartment models. We show that the incorporation of realistic reductions in CTH during functional hyperemia improves model fits to dynamic blood flow and oxygenation changes acquired during functional activation in a literature animal study. Our results support earlier observations that oxygen diffusion properties seemingly change during various physiologic stimuli, and posit that this phenomenon is related to parallel changes in capillary flow patterns. Furthermore, our results suggest that CTH must be taken into account when inferring brain metabolism from changes in blood flow- or blood oxygenation-based signals . PMID:25492112

  4. Effects of breathing a hyperoxic hypercapnic gas mixture on blood oxygenation and vascularity of head-and-neck tumors as measured by magnetic resonance imaging

    International Nuclear Information System (INIS)

    Rijpkema, Mark; Kaanders, Johannes H.A.M.; Joosten, Frank; Kogel, Albert J. van der; Heerschap, Arend

    2002-01-01

    Purpose: For head-and-neck tumors, breathing a hyperoxic hypercapnic gas mixture and administration of nicotinamide has been shown to result in a significantly improved tumor response to accelerated radiotherapy (ARCON, Accelerated Radiotherapy with CarbOgen and Nicotinamide). This may be caused by improved tumor oxygenation, possibly mediated by vascular effects. In this study, both blood oxygenation and vascular effects of breathing a hyperoxic hypercapnic gas mixture (98% O 2 +2% CO 2 ) were assessed by magnetic resonance imaging (MRI) in patients with head-and-neck tumors. Methods and Materials: Tumor vascularity and oxygenation were investigated by dynamic gadolinium contrast-enhanced MRI and blood oxygen level dependent (BOLD) MRI, respectively. Eleven patients with primary head-and-neck tumors were each measured twice; with and without breathing the hyperoxic hypercapnic gas mixture. Results: BOLD MR imaging revealed a significant increase of the MRI time constant of transverse magnetization decay (T 2 *) in the tumor during hypercapnic hyperoxygenation, which correlates to a decrease of the deoxyhemoglobin concentration. No changes in overall tumor vascularity were observed, as measured by the gadolinium contrast uptake rate in the tumor. Conclusion: Breathing a hyperoxic hypercapnic gas mixture improves tumor blood oxygenation in patients with head-and-neck tumors, which may contribute to the success of the ARCON therapy

  5. Modeling of Cerebral Oxygen Transport Based on In vivo Microscopic Imaging of Microvascular Network Structure, Blood Flow, and Oxygenation.

    Science.gov (United States)

    Gagnon, Louis; Smith, Amy F; Boas, David A; Devor, Anna; Secomb, Timothy W; Sakadžić, Sava

    2016-01-01

    Oxygen is delivered to brain tissue by a dense network of microvessels, which actively control cerebral blood flow (CBF) through vasodilation and contraction in response to changing levels of neural activity. Understanding these network-level processes is immediately relevant for (1) interpretation of functional Magnetic Resonance Imaging (fMRI) signals, and (2) investigation of neurological diseases in which a deterioration of neurovascular and neuro-metabolic physiology contributes to motor and cognitive decline. Experimental data on the structure, flow and oxygen levels of microvascular networks are needed, together with theoretical methods to integrate this information and predict physiologically relevant properties that are not directly measurable. Recent progress in optical imaging technologies for high-resolution in vivo measurement of the cerebral microvascular architecture, blood flow, and oxygenation enables construction of detailed computational models of cerebral hemodynamics and oxygen transport based on realistic three-dimensional microvascular networks. In this article, we review state-of-the-art optical microscopy technologies for quantitative in vivo imaging of cerebral microvascular structure, blood flow and oxygenation, and theoretical methods that utilize such data to generate spatially resolved models for blood flow and oxygen transport. These "bottom-up" models are essential for the understanding of the processes governing brain oxygenation in normal and disease states and for eventual translation of the lessons learned from animal studies to humans.

  6. Blood conservation with membrane oxygenators and dipyridamole.

    Science.gov (United States)

    Teoh, K H; Christakis, G T; Weisel, R D; Madonik, M M; Ivanov, J; Wong, P Y; Mee, A V; Levitt, D; Benak, A; Reilly, P

    1987-07-01

    Cardiopulmonary bypass induces platelet activation and dysfunction, which result in platelet deposition and depletion. Reduced platelet numbers and abnormal platelet function may contribute to postoperative bleeding. A membrane oxygenator may preserve platelets and reduce bleeding more than a bubble oxygenator, and the antiplatelet agent dipyridamole may protect platelets intraoperatively and reduce bleeding postoperatively. A prospective randomized trial was performed in 44 patients undergoing elective coronary artery bypass grafting to assess the effects of the membrane oxygenator and dipyridamole on platelet counts, platelet activation products, and postoperative bleeding. Patients who were randomized to receive a bubble oxygenator and no dipyridamole had the lowest postoperative platelet counts, the greatest blood loss, and the most blood products transfused. Platelet counts were highest and blood loss was least in patients randomized to receive a membrane oxygenator and dipyridamole (p less than .05). A bubble oxygenator with dipyridamole and a membrane oxygenator without dipyridamole resulted in intermediate postoperative platelet counts and blood loss. Arterial thromboxane B2 and platelet factor 4 concentrations were elevated on cardiopulmonary bypass in all groups. Both the membrane oxygenator and dipyridamole were independently effective (by multivariate analysis) in preserving platelets. Optimal blood conservation was achieved with a membrane oxygenator and dipyridamole.

  7. Simultaneous imaging of cerebral partial pressure of oxygen and blood flow during functional activation and cortical spreading depression

    Science.gov (United States)

    Sakadžić, Sava; Yuan, Shuai; Dilekoz, Ergin; Ruvinskaya, Svetlana; Vinogradov, Sergei A.; Ayata, Cenk; Boas, David A.

    2009-01-01

    We developed a novel imaging technique that provides real-time two-dimensional maps of the absolute partial pressure of oxygen and relative cerebral blood flow in rats by combining phosphorescence lifetime imaging with laser speckle contrast imaging. Direct measurement of blood oxygenation based on phosphorescence lifetime is not significantly affected by changes in the optical parameters of the tissue during the experiment. The potential of the system as a novel tool for quantitative analysis of the dynamic delivery of oxygen to support brain metabolism was demonstrated in rats by imaging cortical responses to forepaw stimulation and the propagation of cortical spreading depression waves. This new instrument will enable further study of neurovascular coupling in normal and diseased brain. PMID:19340106

  8. Multi-modal in vivo imaging of brain blood oxygenation, blood flow and neural calcium dynamics during acute seizures

    Science.gov (United States)

    Ringuette, Dene; Jeffrey, Melanie A.; Carlen, Peter L.; Levi, Ofer

    2016-03-01

    Dysfunction of the vascular endothelium has been implicated in the development of epilepsy. To better understand the relation between vascular function and seizure and provide a foundation for interpreting results from functional imaging in chronic disease models, we investigate the relationship between intracellular calcium dynamics and local cerebral blood flow and blood oxygen saturation during acute seizure-like events and pharmacological seizure rescue. To probe the relation between the aforementioned physiological markers in an acute model of epilepsy in rats, we integrated three different optical modalities together with electrophysiological recordings: Laser speckle contrast imaging (LSCI) was used to study changes in flow speeds, Intrinsic optical signal imaging (IOSI) was used to monitor changes in oxygenated, de-oxygenated, and total hemoglobin concentration, and Calcium-sensitive dye imaging was used to monitor intracellular calcium dynamics. We designed a dedicated cortical flow chamber to remove superficial blood and dye resulting from the injection procedure, which reduced spurious artifacts. The near infrared light used for IOSI and LSCI was delivered via a light pipe integrated with the flow chamber to minimize the effect of fluid surface movement on illumination stability. Calcium-sensitive dye was injected via a glass electrode used for recording the local field potential. Our system allowed us to observe and correlate increases in intracellular calcium, blood flow and blood volume during seizure-like events and provide a quantitative analysis of neurovascular coupling changes associated with seizure rescue via injection of an anti-convulsive agent.

  9. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats

    NARCIS (Netherlands)

    L. Zafrani (Lara); B. Ergin (Bulent); Kapucu, A. (Aysegul); C. Ince (Can)

    2016-01-01

    textabstractBackground: The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Methods: Twenty-seven Wistar

  10. The Effects of Acutely Administered 3,4-Methylenedioxymethamphetamine on Spontaneous Brain Function in Healthy Volunteers Measured with Arterial Spin Labeling and Blood Oxygen Level–Dependent Resting State Functional Connectivity

    Science.gov (United States)

    Carhart-Harris, Robin L.; Murphy, Kevin; Leech, Robert; Erritzoe, David; Wall, Matthew B.; Ferguson, Bart; Williams, Luke T.J.; Roseman, Leor; Brugger, Stefan; De Meer, Ineke; Tanner, Mark; Tyacke, Robin; Wolff, Kim; Sethi, Ajun; Bloomfield, Michael A.P.; Williams, Tim M.; Bolstridge, Mark; Stewart, Lorna; Morgan, Celia; Newbould, Rexford D.; Feilding, Amanda; Curran, H. Val; Nutt, David J.

    2015-01-01

    Background The compound 3,4-methylenedioxymethamphetamine (MDMA) is a potent monoamine releaser that produces an acute euphoria in most individuals. Methods In a double-blind, placebo-controlled, balanced-order study, MDMA was orally administered to 25 physically and mentally healthy individuals. Arterial spin labeling and seed-based resting state functional connectivity (RSFC) were used to produce spatial maps displaying changes in cerebral blood flow (CBF) and RSFC after MDMA administration. Participants underwent two arterial spin labeling and two blood oxygen level–dependent scans in a 90-minute scan session; MDMA and placebo study days were separated by 1 week. Results Marked increases in positive mood were produced by MDMA. Decreased CBF only was observed after MDMA, and this was localized to the right medial temporal lobe (MTL), thalamus, inferior visual cortex, and the somatosensory cortex. Decreased CBF in the right amygdala and hippocampus correlated with ratings of the intensity of global subjective effects of MDMA. The RSFC results complemented the CBF results, with decreases in RSFC between midline cortical regions, the medial prefrontal cortex, and MTL regions, and increases between the amygdala and hippocampus. There were trend-level correlations between these effects and ratings of intense and positive subjective effects. Conclusions The MTLs appear to be specifically implicated in the mechanism of action of MDMA, but further work is required to elucidate how the drug’s characteristic subjective effects arise from its modulation of spontaneous brain activity. PMID:24495461

  11. Photoreactivity of the occipital cortex measured by functional magnetic resonance imaging-blood oxygenation level dependent in migraine patients and healthy volunteers: pathophysiological implications.

    Science.gov (United States)

    Martín, Helena; Sánchez del Río, Margarita; de Silanes, Carlos López; Álvarez-Linera, Juan; Hernández, Juan Antonio; Pareja, Juan A

    2011-01-01

    The brain of migraineurs is hyperexcitable, particularly the occipital cortex, which is probably hypersensitive to light. Photophobia or hypersensitivity to light may be accounted for by an increased excitability of trigeminal, the visual pathways, and the occipital cortex. To study light sensitivity and photophobia by assessing the response to light stimuli with functional magnetic resonance imaging-blood oxygenation level dependent (fMRI-BOLD) of the occipital cortex in migraineurs and in controls. Also, to try to decipher the contribution of the occipital cortex to photophobia and whether the cortical reactivity of migraineurs may be part of a constitutional (defensive) mechanism or represents an acquired (sensitization) phenomenon. Nineteen patients with migraine (7 with aura and 12 without aura) and 19 controls were studied with fMRI-BOLD during 4 increasing light intensities. Eight axial image sections of 0.5 cm that covered the occipital cortex were acquired for each intensity. We measured the extension and the intensity of activation for every light stimuli. Photophobia was estimated according to a 0 to 3 semiquantitative scale of light discomfort. Migraineurs had a significantly higher number of fMRI-activated voxels at low (320.4 for migraineurs [SD = 253.9] and 164.3 for controls [SD = 102.7], P = .027) and medium-low luminance levels (501.2 for migraineurs [SD = 279.5] and 331.1 for controls [SD = 194.3], P = .034) but not at medium-high (579.5 for migraineurs [SD = 201.4] and 510.2 for controls [SD = 239.5], P = .410) and high light stimuli (496.2 for migraineurs [SD = 216.2] and 394.7 for controls [SD = 240], P = .210). No differences were found with respect to the voxel activation intensity (amplitude of the BOLD wave) between migraineurs and controls (8.98 [SD = 2.58] vs 7.99 [SD = 2.57], P = .25; 10.82 [SD = 3.27] vs 9.81 [SD = 3.19], P = .31; 11.90 [SD = 3.18] vs 11.06 [SD = 2.56], P = .62; 11.45 [SD = 2.65] vs 10.25 [SD = 2.22], P = .16). Light

  12. Functional interactions of HIV-infection and methamphetamine dependence during motor programming.

    Science.gov (United States)

    Archibald, Sarah L; Jacobson, Mark W; Fennema-Notestine, Christine; Ogasawara, Miki; Woods, Steven P; Letendre, Scott; Grant, Igor; Jernigan, Terry L

    2012-04-30

    Methamphetamine (METH) dependence is frequently comorbid with HIV infection and both have been linked to alterations of brain structure and function. In a previous study, we showed that the brain volume loss characteristic of HIV infection contrasts with METH-related volume increases in striatum and parietal cortex, suggesting distinct neurobiological responses to HIV and METH (Jernigan et al., 2005). Functional magnetic resonance imaging (fMRI) has the potential to reveal functional interactions between the effects of HIV and METH. In the present study, 50 participants were studied in four groups: an HIV+ group, a recently METH-dependent group, a dually affected group, and a group of unaffected community comparison subjects. An fMRI paradigm consisting of motor sequencing tasks of varying levels of complexity was administered to examine blood oxygenation level dependent (BOLD) changes. Within all groups, activity increased significantly with increasing task complexity in large clusters within sensorimotor and parietal cortex, basal ganglia, cerebellum, and cingulate. The task complexity effect was regressed on HIV status, METH status, and the HIV×METH interaction term in a simultaneous multiple regression. HIV was associated with less complexity-related activation in striatum, whereas METH was associated with less complexity-related activation in parietal regions. Significant interaction effects were observed in both cortical and subcortical regions; and, contrary to expectations, the complexity-related activation was less aberrant in dually affected than in single risk participants, in spite of comparable levels of neurocognitive impairment among the clinical groups. Thus, HIV and METH dependence, perhaps through their effects on dopaminergic systems, may have opposing functional effects on neural circuits involved in motor programming. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  13. Oxygen dependency of porfiromycin cytotoxicity

    International Nuclear Information System (INIS)

    Marshall, R.S.; Rauth, A.M.

    1987-01-01

    The authors determined the oxygen dependency of toxicity for the bioreductive alkylating agents mitomycin C (MMC) and porfiromycin (PM) to investigate whether the toxicities of these agents increase in the range of oxygen tensions over which cells become increasingly radioresistant. In the present work the oxygen dependency of PM in CHO cells was determined by assaying survival as a function of time of exposure to 1.0 μg/ml PM under various known levels of oxygen. While PM demonstrated preferential hypoxic cell toxicity, aerobic cell survival was reduced ten-fold after five hours of exposure. Conversely, PM toxicity after a five hour hypoxic exposure to <0.001% oxygen appeared to be greater than that observed for similar MMC exposures, suggesting that PM may be more selective than MMC in killing hypoxic rather than aerobic cells. The authors are currently investigating this preferential toxicity in two human cell lines, one of which is resistant to these agents. At present, these observations suggest that PM may be more effective than MMC at destroying tumour cells in regions of intermediate and low oxygen tensions which may survive radiotherapy, though the range of oxygen tensions which mediate toxicity is similar for both agents

  14. Maternal blood metal levels and fetal markers of metabolic function

    Energy Technology Data Exchange (ETDEWEB)

    Ashley-Martin, Jillian [Perinatal Epidemiology Research Unit, Dalhousie University, Halifax, Nova Scotia (Canada); Dodds, Linda, E-mail: l.dodds@dal.ca [Perinatal Epidemiology Research Unit, Dalhousie University, Halifax, Nova Scotia (Canada); Arbuckle, Tye E. [Health Canada, Ottawa (Canada); Ettinger, Adrienne S. [Yale University, New Haven, CT (United States); Shapiro, Gabriel D. [University of Montreal, Montreal, Quebec (Canada); CHU Sainte-Justine Research Centre, Montreal, Quebec (Canada); Fisher, Mandy [Health Canada, Ottawa (Canada); Taback, Shayne [University of Manitoba, Winnipeg, Manitoba (Canada); Bouchard, Maryse F. [University of Montreal, Montreal, Quebec (Canada); Monnier, Patricia [McGill University, Montreal, Quebec (Canada); Dallaire, Renee [Laval University, Quebec City, Quebec (Canada); Fraser, William D. [University of Montreal, Montreal, Quebec (Canada); CHU Sainte-Justine Research Centre, Montreal, Quebec (Canada)

    2015-01-15

    Exposure to metals commonly found in the environment has been hypothesized to be associated with measures of fetal growth but the epidemiological literature is limited. The Maternal–Infant Research on Environmental Chemicals (MIREC) study recruited 2001 women during the first trimester of pregnancy from 10 Canadian sites. Our objective was to assess the association between prenatal exposure to metals (lead, arsenic, cadmium, and mercury) and fetal metabolic function. Average maternal metal concentrations in 1st and 3rd trimester blood samples were used to represent prenatal metals exposure. Leptin and adiponectin were measured in 1363 cord blood samples and served as markers of fetal metabolic function. Polytomous logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between metals and both high (≥90%) and low (≤10%) fetal adiponectin and leptin levels. Leptin levels were significantly higher in female infants compared to males. A significant relationship between maternal blood cadmium and odds of high leptin was observed among males but not females in adjusted models. When adjusting for birth weight z-score, lead was associated with an increased odd of high leptin. No other significant associations were found at the top or bottom 10th percentile in either leptin or adiponectin models. This study supports the proposition that maternal levels of cadmium influence cord blood adipokine levels in a sex-dependent manner. Further investigation is required to confirm these findings and to determine how such findings at birth will translate into childhood anthropometric measures. - Highlights: • We determined relationships between maternal metal levels and cord blood adipokines. • Cord blood leptin levels were higher among female than male infants. • Maternal cadmium was associated with elevated leptin in male, not female infants. • No significant associations were observed between metals and

  15. Maternal blood metal levels and fetal markers of metabolic function

    International Nuclear Information System (INIS)

    Ashley-Martin, Jillian; Dodds, Linda; Arbuckle, Tye E.; Ettinger, Adrienne S.; Shapiro, Gabriel D.; Fisher, Mandy; Taback, Shayne; Bouchard, Maryse F.; Monnier, Patricia; Dallaire, Renee; Fraser, William D.

    2015-01-01

    Exposure to metals commonly found in the environment has been hypothesized to be associated with measures of fetal growth but the epidemiological literature is limited. The Maternal–Infant Research on Environmental Chemicals (MIREC) study recruited 2001 women during the first trimester of pregnancy from 10 Canadian sites. Our objective was to assess the association between prenatal exposure to metals (lead, arsenic, cadmium, and mercury) and fetal metabolic function. Average maternal metal concentrations in 1st and 3rd trimester blood samples were used to represent prenatal metals exposure. Leptin and adiponectin were measured in 1363 cord blood samples and served as markers of fetal metabolic function. Polytomous logistic regression models were used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the association between metals and both high (≥90%) and low (≤10%) fetal adiponectin and leptin levels. Leptin levels were significantly higher in female infants compared to males. A significant relationship between maternal blood cadmium and odds of high leptin was observed among males but not females in adjusted models. When adjusting for birth weight z-score, lead was associated with an increased odd of high leptin. No other significant associations were found at the top or bottom 10th percentile in either leptin or adiponectin models. This study supports the proposition that maternal levels of cadmium influence cord blood adipokine levels in a sex-dependent manner. Further investigation is required to confirm these findings and to determine how such findings at birth will translate into childhood anthropometric measures. - Highlights: • We determined relationships between maternal metal levels and cord blood adipokines. • Cord blood leptin levels were higher among female than male infants. • Maternal cadmium was associated with elevated leptin in male, not female infants. • No significant associations were observed between metals and

  16. Blood oxygenation level dependent signal and neuronal adaptation to optogenetic and sensory stimulation in somatosensory cortex in awake animals.

    Science.gov (United States)

    Aksenov, Daniil P; Li, Limin; Miller, Michael J; Wyrwicz, Alice M

    2016-11-01

    The adaptation of neuronal responses to stimulation, in which a peak transient response is followed by a sustained plateau, has been well-studied. The blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal has also been shown to exhibit adaptation on a longer time scale. However, some regions such as the visual and auditory cortices exhibit significant BOLD adaptation, whereas other such as the whisker barrel cortex may not adapt. In the sensory cortex a combination of thalamic inputs and intracortical activity drives hemodynamic changes, although the relative contributions of these components are not entirely understood. The aim of this study is to assess the role of thalamic inputs vs. intracortical processing in shaping BOLD adaptation during stimulation in the somatosensory cortex. Using simultaneous fMRI and electrophysiology in awake rabbits, we measured BOLD, local field potentials (LFPs), single- and multi-unit activity in the cortex during whisker and optogenetic stimulation. This design allowed us to compare BOLD and haemodynamic responses during activation of the normal thalamocortical sensory pathway (i.e., both inputs and intracortical activity) vs. the direct optical activation of intracortical circuitry alone. Our findings show that whereas LFP and multi-unit (MUA) responses adapted, neither optogenetic nor sensory stimulation produced significant BOLD adaptation. We observed for both paradigms a variety of excitatory and inhibitory single unit responses. We conclude that sensory feed-forward thalamic inputs are not primarily responsible for shaping BOLD adaptation to stimuli; but the single-unit results point to a role in this behaviour for specific excitatory and inhibitory neuronal sub-populations, which may not correlate with aggregate neuronal activity. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  17. Blood transfusion improves renal oxygenation and renal function in sepsis-induced acute kidney injury in rats

    NARCIS (Netherlands)

    Zafrani, Lara; Ergin, Bulent; Kapucu, Aysegul; Ince, Can

    2016-01-01

    The effects of blood transfusion on renal microcirculation during sepsis are unknown. This study aimed to investigate the effect of blood transfusion on renal microvascular oxygenation and renal function during sepsis-induced acute kidney injury. Twenty-seven Wistar albino rats were randomized into

  18. Why do premature newborn infants display elevated blood adenosine levels?

    Science.gov (United States)

    Panfoli, Isabella; Cassanello, Michela; Bruschettini, Matteo; Colella, Marina; Cerone, Roberto; Ravera, Silvia; Calzia, Daniela; Candiano, Giovanni; Ramenghi, Luca

    2016-05-01

    Our preliminary data show high levels of adenosine in the blood of very low birth weight (VLBW) infants, positively correlating to their prematurity (i.e. body weight class). This prompted us to look for a mechanism promoting such impressive adenosine increase. We hypothesized a correlation with oxygen challenge. In fact, it is recognized that either oxygen lack or its excess contribute to the pathogenesis of the injuries of prematurity, such as retinopathy (ROP) and periventricular white matter lesions (PWMI). The optimal concentration of oxygen for resuscitation of VLBW infants is currently under revision. We propose that the elevated adenosine blood concentrations of VLBW infants recognizes two sources. The first could be its activity-dependent release from unmyelinated brain axons. Adenosine in this respect would be an end-product of the hypometabolic VLBW newborn unmyelinated axon intensely firing in response to the environmental stimuli consequent to premature birth. Adenosine would be eventually found in the blood due to blood-brain barrier immaturity. In fact, adenosine is the primary activity-dependent signal promoting differentiation of premyelinating oligodendrocyte progenitor cells (OPC) into myelinating cells in the Central Nervous System, while inhibiting their proliferation and inhibiting synaptic function. The second, would be the ecto-cellular ATP synthesized by the endothelial cell plasmalemma exposed to ambient oxygen concentrations due to premature breathing, especially in lung. ATP would be rapidly transformed into adenosine by the ectonucleotidase activities such as NTPDase I (CD39), and NT5E (CD73). An ectopic extra-mitochondrial aerobic ATP synthetic ability was reported in many cell plasma-membranes, among which endothelial cells. The potential implications of the cited hypotheses for the neonatology area would be great. The amount of oxygen administration for reviving of newborns would find a molecular basis for its assessment. VLBW

  19. Relationship between level of forage intake, blood flow and oxygen consumption by splanchnic tissues of sheep fed a tropical grass forage.

    Science.gov (United States)

    Hentz, F; Kozloski, G V; Zeni, D; Brun, M V; Stefanello, S

    2017-02-01

    Four Polwarth castrated male sheep (42 ± 4.4 kg live weight (LW) surgically implanted with chronic indwelling catheters into the mesenteric, portal and hepatic veins, housed in metabolism cages and offered Cynodon sp. hay at rates (g of dry matter (DM)/kg LW) of 7, 14, 21 or ad libitum, were used in a 4 × 4 Latin square experiment to evaluate the effect of the level of forage intake on blood flow and oxygen consumption by the portal-drained viscera (PDV), liver and total splanchnic tissues (ST). The portal blood flow and the oxygen consumption by PDV linearly increased at increased organic matter (OM) intake. No effect of level of OM intake was obtained for the hepatic artery blood flow and oxygen consumption by liver. As a consequence, the level of OM intake only tended to directly affect hepatic blood flow and oxygen consumption by total ST. Oxygen consumption was linearly and positively related to blood flow across PDV, liver and total ST. The heat production by PDV and total ST, as proportion of metabolizable energy (ME) intake, decreased curvilinearly at increased ME intake. In conclusion, the oxygen consumption by PDV, but not by liver, was directly related to the level of forage intake by sheep. Moreover, when ingested at levels below maintenance, most of ME was spent as heat produced by ST. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

  20. Relationship between retinal blood flow and arterial oxygen.

    Science.gov (United States)

    Cheng, Richard W; Yusof, Firdaus; Tsui, Edmund; Jong, Monica; Duffin, James; Flanagan, John G; Fisher, Joseph A; Hudson, Chris

    2016-02-01

    Vascular reactivity, the response of the vessels to a vasoactive stimulus such as hypoxia and hyperoxia, can be used to assess the vascular range of adjustment in which the vessels are able to compensate for changes in PO2. Previous studies in the retina have not accurately quantified retinal vascular responses and precisely targeted multiple PaO2 stimuli at the same time as controlling the level of carbon dioxide, thus precluding them from modelling the relationship between retinal blood flow and oxygen. The present study modelled the relationship between retinal blood flow and PaO2, showing them to be a combined linear and hyperbolic function. This model demonstrates that the resting tonus of the vessels is at the mid-point and that they have great vascular range of adjustment, compensating for decreases in oxygen above a PETCO2 of 32-37 mmHg but being limited below this threshold. Retinal blood flow (RBF) increases in response to a reduction in oxygen (hypoxia) but decreases in response to increased oxygen (hyperoxia). However, the relationship between blood flow and the arterial partial pressure of oxygen has not been quantified and modelled in the retina, particularly in the vascular reserve and resting tonus of the vessels. The present study aimed to determine the limitations of the retinal vasculature by modelling the relationship between RBF and oxygen. Retinal vascular responses were measured in 13 subjects for eight different blood gas conditions, with the end-tidal partial pressure of oxygen (PETCO2) ranging from 40-500 mmHg. Retinal vascular response measurements were repeated twice; using the Canon laser blood flowmeter (Canon Inc., Tokyo, Japan) during the first visit and using Doppler spectral domain optical coherence tomography during the second visit. We determined that the relationship between RBF and PaO2 can be modelled as a combination of hyperbolic and linear functions. We concluded that RBF compensated for decreases in arterial oxygen content

  1. Erythrocyte signal transduction pathways, their oxygenation dependence and functional significance.

    Science.gov (United States)

    Barvitenko, Nadezhda N; Adragna, Norma C; Weber, Roy E

    2005-01-01

    Erythrocytes play a key role in human and vertebrate metabolism. Tissue O2 supply is regulated by both hemoglobin (Hb)-O2 affinity and erythrocyte rheology, a key determinant of tissue perfusion. Oxygenation-deoxygenation transitions of Hb may lead to re-organization of the cytoskeleton and signalling pathways activation/deactivation in an O2-dependent manner. Deoxygenated Hb binds to the cytoplasmic domain of the anion exchanger band 3, which is anchored to the cytoskeleton, and is considered a major mechanism underlying the oxygenation-dependence of several erythrocyte functions. This work discusses the multiple modes of Hb-cytoskeleton interactions. In addition, it reviews the effects of Mg2+, 2,3-diphosphoglycerate, NO, shear stress and Ca2+, all factors accompanying the oxygenation-deoxygenation cycle in circulating red cells. Due to the extensive literature on the subject, the data discussed here, pertain mainly to human erythrocytes whose O2 affinity is modulated by 2,3-diphosphoglycerate, ectothermic vertebrate erythrocytes that use ATP, and to bird erythrocytes that use inositol pentaphosphate. Copyright 2005 S. Karger AG, Basel.

  2. A neural measure of behavioral engagement: task-residual low-frequency blood oxygenation level-dependent activity in the precuneus.

    Science.gov (United States)

    Zhang, Sheng; Li, Chiang-Shan Ray

    2010-01-15

    Brain imaging has provided a useful tool to examine the neural processes underlying human cognition. A critical question is whether and how task engagement influences the observed regional brain activations. Here we highlighted this issue and derived a neural measure of task engagement from the task-residual low-frequency blood oxygenation level-dependent (BOLD) activity in the precuneus. Using independent component analysis, we identified brain regions in the default circuit - including the precuneus and medial prefrontal cortex (mPFC) - showing greater activation during resting as compared to task residuals in 33 individuals. Time series correlations with the posterior cingulate cortex as the seed region showed that connectivity with the precuneus was significantly stronger during resting as compared to task residuals. We hypothesized that if the task-residual BOLD activity in the precuneus reflects engagement, it should account for a certain amount of variance in task-related regional brain activation. In an additional experiment of 59 individuals performing a stop signal task, we observed that the fractional amplitude of low-frequency fluctuation (fALFF) of the precuneus but not the mPFC accounted for approximately 10% of the variance in prefrontal activation related to attentional monitoring and response inhibition. Taken together, these results suggest that task-residual fALFF in the precuneus may be a potential indicator of task engagement. This measurement may serve as a useful covariate in identifying motivation-independent neural processes that underlie the pathogenesis of a psychiatric or neurological condition.

  3. Global brain blood-oxygen level responses to autonomic challenges in obstructive sleep apnea.

    Directory of Open Access Journals (Sweden)

    Paul M Macey

    Full Text Available Obstructive sleep apnea (OSA is accompanied by brain injury, perhaps resulting from apnea-related hypoxia or periods of impaired cerebral perfusion. Perfusion changes can be determined indirectly by evaluation of cerebral blood volume and oxygenation alterations, which can be measured rapidly and non-invasively with the global blood oxygen level dependent (BOLD signal, a magnetic resonance imaging procedure. We assessed acute BOLD responses in OSA subjects to pressor challenges that elicit cerebral blood flow changes, using a two-group comparative design with healthy subjects as a reference. We separately assessed female and male patterns, since OSA characteristics and brain injury differ between sexes. We studied 94 subjects, 37 with newly-diagnosed, untreated OSA (6 female (age mean ± std: 52.1±8.1 yrs; apnea/hypopnea index [AHI]: 27.7±15.6 events/hr and 31 male 54.3±8.4 yrs; AHI: 37.4±19.6 events/hr, and 20 female (age 50.5±8.1 yrs and 37 male (age 45.6±9.2 yrs healthy control subjects. We measured brain BOLD responses every 2 s while subjects underwent cold pressor, hand grip, and Valsalva maneuver challenges. The global BOLD signal rapidly changed after the first 2 s of each challenge, and differed in magnitude between groups to two challenges (cold pressor, hand grip, but not to the Valsalva maneuver (repeated measures ANOVA, p<0.05. OSA females showed greater differences from males in response magnitude and pattern, relative to healthy counterparts. Cold pressor BOLD signal increases (mean ± adjusted standard error at the 8 s peak were: OSA 0.14±0.08% vs. Control 0.31±0.06%, and hand grip at 6 s were: OSA 0.08±0.03% vs. Control at 0.30±0.02%. These findings, indicative of reduced cerebral blood flow changes to autonomic challenges in OSA, complement earlier reports of altered resting blood flow and reduced cerebral artery responsiveness. Females are more affected than males, an outcome which may contribute to the sex

  4. Renal Blood Flow, Glomerular Filtration Rate, and Renal Oxygenation in Early Clinical Septic Shock.

    Science.gov (United States)

    Skytte Larsson, Jenny; Krumbholz, Vitus; Enskog, Anders; Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

    2018-06-01

    Data on renal hemodynamics, function, and oxygenation in early clinical septic shock are lacking. We therefore measured renal blood flow, glomerular filtration rate, renal oxygen consumption, and oxygenation in patients with early septic shock. Prospective comparative study. General and cardiothoracic ICUs. Patients with norepinephrine-dependent early septic shock (n = 8) were studied within 24 hours after arrival in the ICU and compared with postcardiac surgery patients without acute kidney injury (comparator group, n = 58). None. Data on systemic hemodynamics and renal variables were obtained during two 30-minute periods. Renal blood flow was measured by the infusion clearance of para-aminohippuric acid, corrected for renal extraction of para-aminohippuric acid. Renal filtration fraction was measured by renal extraction of chromium-51 labeled EDTA. Renal oxygenation was estimated from renal oxygen extraction. Renal oxygen delivery (-24%; p = 0.037) and the renal blood flow-to-cardiac index ratio (-21%; p = 0.018) were lower, renal vascular resistance was higher (26%; p = 0.027), whereas renal blood flow tended to be lower (-19%; p = 0.068) in the septic group. Glomerular filtration rate (-32%; p = 0.006) and renal sodium reabsorption (-29%; p = 0.014) were both lower in the septic group. Neither renal filtration fraction nor renal oxygen consumption differed significantly between groups. Renal oxygen extraction was significantly higher in the septic group (28%; p = 0.022). In the septic group, markers of tubular injury were elevated. In early clinical septic shock, renal function was lower, which was accompanied by renal vasoconstriction, a lower renal oxygen delivery, impaired renal oxygenation, and tubular sodium reabsorption at a high oxygen cost compared with controls.

  5. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    OpenAIRE

    Golub, Aleksander S.; Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po...

  6. Relation of Mitochondrial Oxygen Consumption in Peripheral Blood Mononuclear Cells to Vascular Function in Type 2 Diabetes Mellitus

    Science.gov (United States)

    Hartman, Mor-Li; Shirihai, Orian S.; Holbrook, Monika; Xu, Guoquan; Kocherla, Marsha; Shah, Akash; Fetterman, Jessica L.; Kluge, Matthew A.; Frame, Alissa A.; Hamburg, Naomi M.; Vita, Joseph A.

    2014-01-01

    Recent studies have shown mitochondrial dysfunction and increased production of reactive oxygen species in peripheral blood mononuclear cells (PBMC’s) and endothelial cells from patients with diabetes mellitus. Mitochondria oxygen consumption is coupled to ATP production and also occurs in an uncoupled fashion during formation of reactive oxygen species by components of the electron transport chain and other enzymatic sites. We therefore hypothesized that diabetes would be associated with higher total and uncoupled oxygen consumption in PBMC’s that would correlate with endothelial dysfunction. We developed a method to measure oxygen consumption in freshly isolated PBMC’s and applied it to 26 patients with type 2 diabetes mellitus and 28 non-diabetic controls. Basal (192±47 vs. 161±44 pMoles/min, P=0.01), uncoupled (64±16 vs. 53±16 pMoles/min, P=0.007), and maximal (795±87 vs. 715±128 pMoles/min, P=0.01) oxygen consumption rates were higher in diabetic patients compared to controls. There were no significant correlations between oxygen consumption rates and endothelium-dependent flow-mediated dilation measured by vascular ultrasound. Non-endothelium-dependent nitroglycerin-mediated dilation was lower in diabetics (10.1±6.6 vs. 15.8±4.8%, P=0.03) and correlated with maximal oxygen consumption (R= −0.64, P=0.001). In summary, we found that diabetes mellitus is associated with a pattern of mitochondrial oxygen consumption consistent with higher production of reactive oxygen species. The correlation between oxygen consumption and nitroglycerin-mediated dilation may suggest a link between mitochondrial dysfunction and vascular smooth muscle cell dysfunction that merits further study. Finally, the described method may have utility for assessment of mitochondrial function in larger scale observational and interventional studies in humans. PMID:24558030

  7. Contrast media effect on interleukin-2 levels in human plasma in vitro

    International Nuclear Information System (INIS)

    Napolov, Yu.K.; Borsukova, N.M.; Shimanovskij, N.L.

    1992-01-01

    As shown in the study of bilignost, iodamide and triombrast action on interleukin-2 (IL-2) level in human plasma in vitro, these contrast media (2.5x10 -2 -2.5x10 -4 M) elevate IL-2 content in blood plasma of sensitive to contrast media subjects in dose-dependent manner

  8. A preliminary study of murine walker-256 tumor hypoxia detected by blood oxygen level dependent-MR

    International Nuclear Information System (INIS)

    Zhang Shengjian; Mao Jian; Wu Bin; Peng Weijun

    2013-01-01

    Objective: To establish Walker-256 transplantation tumor model in SD Rats. To study of R_2"* signal changes on murine Walker-256 tumor after inhaling Carbogen by blood oxygen level dependent (BOLD)-MR, and to explore the feasibility of BOLD-MRI on detecting tumor hypoxia. Methods: Walker-256 tumor cell implanted subcutaneously in right lower abdomen of 95 female SD rats. MR was performed on the tumor-forming rats when the maximum diameter of tumor reached 1-3 cm, using a 3.0 T MR scanner equipped with a 3 inch animal surface coil. BOLD-MRI was done by using a multiecho SPGR sequence during inhaling air and at 10 minute after inhaling Carbogen, respectively. All images were transferred to GE ADW 4.3 workstation, then a baseline R_2"* (R_2"* a) and R_2"* (R_2"* b) after inhaling Carbogen of tumor was calculated using R_2 Star analysis software and ΔR_2"* was calculated through ΔR_2"* = R_2"* b -R_2"* a", meanwhile the volume of tumor were calculated as well. The difference of R_2"* signal pre and post-inhaling of Carbogen was compared with a paired t test, Pearson correlation was calculated between R_2"* a, ΔR_2"* and the volume of tumor, respectively. The correlation between ΔR_2"* and R_2"* a was also assessed by Pearson correlation. Results: Sixty-eight of ninety-five female SD rats formed the tumor (71.6%). The volume of tumor was from 352 to 13 173 mm"3. Mean ΔR_2"* decreased significantly (-2.26 ± 3.90) s"-"1 from (41.18 ± 22.29) s"-"1 during breathing air to (38.91 ± 21.35) s"-"1 10 min after inhaling Carbogen (t = 4.01, P 0.05). Conclusions: BOLD-MRI can detect the R_2"* signal change of murine Walker-256 tumor pre-and post-inhaling of Carbogen. The R_2"* signal showed significant decrease after inhaling Carbogen, however, the individual variation was remarkable. (authors)

  9. Effects of Intranasal Oxytocin on the Blood Oxygenation Level-Dependent Signal in Food Motivation and Cognitive Control Pathways in Overweight and Obese Men.

    Science.gov (United States)

    Plessow, Franziska; Marengi, Dean A; Perry, Sylvia K; Felicione, Julia M; Franklin, Rachel; Holmes, Tara M; Holsen, Laura M; Makris, Nikolaos; Deckersbach, Thilo; Lawson, Elizabeth A

    2018-02-01

    Recent research indicates that the hypothalamic neuropeptide hormone oxytocin is a key central nervous system factor in the regulation of food intake and weight. However, the mechanisms underlying the anorexigenic effects of oxytocin in humans are unknown and critical to study to consider oxytocin as a neurohormonal weight loss treatment. We performed a randomized, double-blind, placebo-controlled crossover study with single-dose intranasal oxytocin (24 IU) in ten overweight or obese, otherwise healthy men. Following oxytocin/placebo administration, participants completed an established functional magnetic resonance imaging food motivation paradigm. We hypothesized that oxytocin would reduce the blood oxygenation level-dependent (BOLD) signal to high-calorie food vs non-food visual stimuli in the ventral tegmental area (VTA), the origin of the mesolimbic dopaminergic reward system. Following oxytocin administration, compared to placebo, participants showed bilateral VTA hypoactivation to high-calorie food stimuli. A secondary exploratory whole-brain analysis revealed hypoactivation in additional hedonic (orbitofrontal cortex, insula, globus pallidus, putamen, hippocampus, and amygdala) and homeostatic (hypothalamus) food motivation and hyperactivation in cognitive control (anterior cingulate and frontopolar cortex) brain regions following oxytocin administration vs placebo. Oxytocin administration reduces the BOLD signal in reward-related food motivation brain regions, providing a potential neurobiological mechanism for the anorexigenic oxytocin effects in humans. Furthermore, our data indicate that oxytocin administration reduces activation in homeostatic and increases activation in cognitive control brain regions critically involved in regulating food intake and resolving affective conflict, respectively. Future studies are required to link these changes in brain activation to oxytocin effects on food intake and weight.

  10. Effects of the oxygenation level on formation of different reactive oxygen species during photodynamic therapy.

    Science.gov (United States)

    Price, Michael; Heilbrun, Lance; Kessel, David

    2013-01-01

    We examined the effect of the oxygenation level on efficacy of two photosensitizing agents, both of which target lysosomes for photodamage, but via different photochemical pathways. Upon irradiation, the chlorin termed NPe6 forms singlet oxygen in high yield while the bacteriopheophorbide WST11 forms only oxygen radicals (in an aqueous environment). Photokilling efficacy by WST11 in cell culture was impaired when the atmospheric oxygen concentration was reduced from 20% to 1%, while photokilling by NPe6 was unaffected. Studies in a cell-free system revealed that the rates of photobleaching of these agents, as a function of the oxygenation level, were correlated with results described above. Moreover, the rate of formation of oxygen radicals by either agent was more sensitive to the level of oxygenation than was singlet oxygen formation by NPe6. These data indicate that the photochemical process that leads to oxygen radical formation is more dependent on the oxygenation level than is the pathway leading to formation of singlet oxygen. © 2013 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2013 The American Society of Photobiology.

  11. Formation of neutrophil extracellular traps under low oxygen level

    Directory of Open Access Journals (Sweden)

    Katja Branitzki-Heinemann

    2016-11-01

    Full Text Available Since their discovery, neutrophil extracellular traps (NETs have been characterized as a fundamental host innate immune defense mechanism. Conversely, excessive NET release may have a variety of detrimental consequences for the host. A fine balance between NET formation and elimination is necessary to sustain a protective effect during an infectious challenge. Our own recently published data revealed that stabilization of hypoxia inducible factor 1α (HIF-1α by the iron chelating HIF-1α-agonist desferoxamine or AKB-4924 enhanced the release of phagocyte extracellular traps. Since HIF-1α is a global regulator of the cellular response to low oxygen, we hypothesized that NET formation may be similarly increased under low oxygen conditions. Hypoxia occurs in tissues during infection or inflammation, mostly due to overconsumption of oxygen by pathogens and recruited immune cells. Therefore, experiments were performed to characterize the formation of NETs under hypoxic oxygen conditions compared to normoxia. Human blood-derived neutrophils were isolated and incubated under normoxic (21% oxygen level and compared to hypoxic (1% conditions. Dissolved oxygen levels were monitored in the primary cell culture using a Fibox4-PSt3 measurement system. The formation of NETs was quantified by fluorescence microscopy in response to the known NET-inducer phorbol 12-myristate 13-acetate (PMA or S. aureus wildtype and a nuclease-deficient mutant. In contrast to our hypothesis, spontaneous NET formation of neutrophils incubated under hypoxia was distinctly reduced compared to control neutrophils incubated under normoxia. Furthermore, neutrophils incubated under hypoxia showed significantly reduced formation of NETs in response to PMA. Gene expression analysis revealed that mRNA level of hif-1α as well as hif-1α target genes was not altered. However, in good correlation to the decreased NET formation under hypoxia, the cholesterol content of the neutrophils was

  12. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    International Nuclear Information System (INIS)

    Kyriacou, P A; Shafqat, K; Pal, S K

    2007-01-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO 2 ) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO 2 ) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO 2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  13. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Science.gov (United States)

    Kyriacou, P. A.; Shafqat, K.; Pal, S. K.

    2007-10-01

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO2) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO2) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO2 sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures. Both pulse

  14. Capillary pericytes regulate cerebral blood flow in health and disease

    DEFF Research Database (Denmark)

    Hall, Catherine N; Reynell, Clare; Gesslein, Bodil

    2014-01-01

    Increases in brain blood flow, evoked by neuronal activity, power neural computation and form the basis of BOLD (blood-oxygen-level-dependent) functional imaging. Whether blood flow is controlled solely by arteriole smooth muscle, or also by capillary pericytes, is controversial. We demonstrate t...

  15. Arterial blood oxygen saturation during blood pressure cuff-induced hypoperfusion

    Energy Technology Data Exchange (ETDEWEB)

    Kyriacou, P A [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Shafqat, K [School of Engineering and Mathematical Sciences, City University, London EC1V 0HB (United Kingdom); Pal, S K [St Andrew' s Centre for Plastic Surgery and Burns, Broomfield Hospital, Chelmsford, CM1 7ET (United Kingdom)

    2007-10-15

    Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO{sub 2}) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Pulse oximeters estimate arterial oxygen saturation by shining light at two different wavelengths, red and infrared, through vascular tissue. In this method the ac pulsatile photoplethysmographic (PPG) signal associated with cardiac contraction is assumed to be attributable solely to the arterial blood component. The amplitudes of the red and infrared ac PPG signals are sensitive to changes in arterial oxygen saturation because of differences in the light absorption of oxygenated and deoxygenated haemoglobin at these two wavelengths. From the ratios of these amplitudes, and the corresponding dc photoplethysmographic components, arterial blood oxygen saturation (SpO{sub 2}) is estimated. Hence, the technique of pulse oximetry relies on the presence of adequate peripheral arterial pulsations, which are detected as photoplethysmographic (PPG) signals. The aim of this study was to investigate the effect of pressure cuff-induced hypoperfusion on photoplethysmographic signals and arterial blood oxygen saturation using a custom made finger blood oxygen saturation PPG/SpO{sub 2} sensor and a commercial finger pulse oximeter. Blood oxygen saturation values from the custom oxygen saturation sensor and a commercial finger oxygen saturation sensor were recorded from 14 healthy volunteers at various induced brachial pressures

  16. Quantification of photocatalytic oxygenation of human blood.

    Science.gov (United States)

    Subrahmanyam, Aryasomayajula; Thangaraj, Paul R; Kanuru, Chandrasekhar; Jayakumar, Albert; Gopal, Jayashree

    2014-04-01

    Photocatalytic oxygenation of human blood is an emerging concept based on the principle of photocatalytic splitting of water into oxygen and hydrogen. This communication reports: (i) a design of a photocatalytic cell (PC) that separates the blood from UV (incident) radiation source, (ii) a pH, temperature and flow controlled circuit designed for quantifying the oxygenation of human blood by photocatalysis and (iii) measuring the current efficacy of ITO/TiO2 nano thin films in oxygenating human blood in a dynamic circuit in real time. The average increase in oxygen saturation was around 5% above baseline compared to control (p<0.0005). We believe this is one of the first attempts to quantify photocatalytic oxygenation of human blood under controlled conditions. Copyright © 2013 IPEM. Published by Elsevier Ltd. All rights reserved.

  17. A comparison of blood nitric oxide metabolites and hemoglobin functional properties among diving mammals

    DEFF Research Database (Denmark)

    Fago, Angela; Parraga, Daniel Garcia; Petersen, Elin E

    2017-01-01

    examined oxygen affinity, sensitivity to 2,3-diphosphoglycerate (DPG) and nitrite reductase activity of the hemoglobin (Hb) to search for possible adaptive variations in these functional properties. We found levels of plasma and red blood cells nitrite similar to those reported for terrestrial mammals...... in blood oxygen affinity among diving mammals likely derive from phenotypic variations in red blood cell DPG levels. The nitrite reductase activities of the Hbs were overall slightly higher than that of human Hb, with the Hb of beluga whale, capable of longest dives, having the highest activity. Taken...

  18. Optical Assay of Erythrocyte Function in Banked Blood

    Science.gov (United States)

    Bhaduri, Basanta; Kandel, Mikhail; Brugnara, Carlo; Tangella, Krishna; Popescu, Gabriel

    2014-09-01

    Stored red blood cells undergo numerous biochemical, structural, and functional changes, commonly referred to as storage lesion. How much these changes impede the ability of erythrocytes to perform their function and, as result, impact clinical outcomes in transfusion patients is unknown. In this study we investigate the effect of the storage on the erythrocyte membrane deformability and morphology. Using optical interferometry we imaged red blood cell (RBC) topography with nanometer sensitivity. Our time-lapse imaging quantifies membrane fluctuations at the nanometer scale, which in turn report on cell stiffness. This property directly impacts the cell's ability to transport oxygen in microvasculature. Interestingly, we found that cells which apparently maintain their normal shape (discocyte) throughout the storage period, stiffen progressively with storage time. By contrast, static parameters, such as mean cell hemoglobin content and morphology do not change during the same period. We propose that our method can be used as an effective assay for monitoring erythrocyte functionality during storage time.

  19. Comparison of renal toxicity after injection of CT contrast medium and MR contrast medium: change of renal function in acute renal failure rat models

    International Nuclear Information System (INIS)

    Han, Young min; Lee, Young Hwan; Kim, Sang Won; Jin, Kong Young; Kim, Won; Chung, Gyung Ho

    2002-01-01

    To determine renal toxicity through changes in renal function after the injection of CT and MRI contrast media into rats in which acute renal failure (ARF) was induced. To cause acute renal failure, the abdominal cavity of 110 male rats each weighing 250-300 gm was opened via a midline incision under anesthesia. Microvascular clamps were placed on both renal arteries and veins to completely block renal blood flow for 45 minutes, and were then removed, allowing blood flow to return to the kidneys. ARF, defined as a two-fold difference in the creatinine level before ARF and 48 hours after, was successfully induced in 60 of the rats. These were divided into two groups: one was injected with CT contrast medium and the other with MRI contrast medium. Each CT and MRI group was divided into a low dose (0.5 cc/kg, 0.2 ml/kg), standard dose (2 cc/kg, 0.8 ml/kg), and high dose (8 cc/kg, 3.2 ml/kg) sub-group; thus, there was a total of six groups with ten rats in each. Blood samples were obtained before ARF, 48 hours after, and 48 hours after contrast injection, and CT scanning and MRI were performed after blood sampling at 48 hours. In each group, creatinine levels 48 hours after contrast injection were compared by means of the ANOVA test. There were no significant differences in creatinine levels between the CT and MRI contrast medium groups (p=0.116), nor between the animals to which different doses of CT and MRI contrast medium, were administered. After both standard and high doses, CT and MRI provided good images. In rats in which acute renal failure was induced, renal function did not change according to whether CT or MRI contrast medium was injected. Thus, the two media induce similar levels of toxicity

  20. Oxygen dependence of respiration in rat spinotrapezius muscle in situ

    Science.gov (United States)

    Pittman, Roland N.

    2012-01-01

    The oxygen dependence of respiration in striated muscle in situ was studied by measuring the rate of decrease of interstitial Po2 [oxygen disappearance curve (ODC)] following rapid arrest of blood flow by pneumatic tissue compression, which ejected red blood cells from the muscle vessels and made the ODC independent from oxygen bound to hemoglobin. After the contribution of photo-consumption of oxygen by the method was evaluated and accounted for, the corrected ODCs were converted into the Po2 dependence of oxygen consumption, V̇o2, proportional to the rate of Po2 decrease. Fitting equations obtained from a model of heterogeneous intracellular Po2 were applied to recover the parameters describing respiration in muscle fibers, with a predicted sigmoidal shape for the dependence of V̇o2 on Po2. This curve consists of two regions connected by the point for critical Po2 of the cell (i.e., Po2 at the sarcolemma when the center of the cell becomes anoxic). The critical Po2 was below the Po2 for half-maximal respiratory rate (P50) for the cells. In six muscles at rest, the rate of oxygen consumption was 139 ± 6 nl O2/cm3·s and mitochondrial P50 was k = 10.5 ± 0.8 mmHg. The range of Po2 values inside the muscle fibers was found to be 4–5 mmHg at the critical Po2. The oxygen dependence of respiration can be studied in thin muscles under different experimental conditions. In resting muscle, the critical Po2 was substantially lower than the interstitial Po2 of 53 ± 2 mmHg, a finding that indicates that V̇o2 under this circumstance is independent of oxygen supply and is discordant with the conventional hypothesis of metabolic regulation of the oxygen supply to tissue. PMID:22523254

  1. [Effect of high blood levels of bile acid on respiratory functions of New Zealand rabbits].

    Science.gov (United States)

    Wang, Fei; Zhao, Cong; Tian, Yinghong; Yin, Yanru

    2013-08-01

    To compare the patterns of respiratory function variations resulting from the classical reflex of blood pressure fall and high blood levels of bile acid, so as to provide evidence for the regulation of respiratory function via bile acids. Seventy New Zealand male Rabbits, under general anesthesia with 20% urethane, were subjected to tracheal intubations and carotid artery cannulations via median incisions of the neck. Using a biological signal acquisition system, the changes in the breathing and blood pressure were observed in response to stimulation of the pneumogastric nerves or to ear vein injections of diluted bile acids or the water solutions of 5 dissociated bile acids. Stimulation of the pneumogastric nerves and injections of diluted bile acids both lowered the blood pressure without significant differences in the total reaction time (T). However, the total respiratory reaction time of bile acids, RT(bile acids), was 9-10 times longer than the total reaction time of blood pressure T(bile acids) (Pacids) were higher than that RR(pneumogastric nerves)resulting from the classical reflex (Pacids), the values of RR(bile acids) were significantly higher than those of RR(bile acids) in RT2(bile acids) interval. UDCA produced no significant influence on blood pressure or respiratory function (Pacid reagents did (Pacids not only act through reflex factors but also have direct effects on respiratory function regulation. Under our experimental conditions, UDCA has no effect on blood pressure or respiratory function, but the other 4 dissociated bile acid reagents can all dose-dependently lower blood pressure and significantly affect respiratory function.

  2. MR measures of renal perfusion, oxygen bioavailability and total renal blood flow in a porcine model: noninvasive regional assessment of renal function.

    Science.gov (United States)

    Wentland, Andrew L; Artz, Nathan S; Fain, Sean B; Grist, Thomas M; Djamali, Arjang; Sadowski, Elizabeth A

    2012-01-01

    Magnetic resonance imaging (MRI) may be a useful adjunct to current methods of evaluating renal function. MRI is a noninvasive imaging modality that has the ability to evaluate the kidneys regionally, which is lacking in current clinical methods. Other investigators have evaluated renal function with MRI-based measurements, such as with techniques to measure cortical and medullary perfusion, oxygen bioavailability and total renal blood flow (TRBF). However, use of all three techniques simultaneously, and therefore the relationships between these MRI-derived functional parameters, have not been reported previously. To evaluate the ability of these MRI techniques to track changes in renal function, we scanned 11 swine during a state of hyperperfusion with acetylcholine and a saline bolus and subsequently scanned during a state of hypoperfusion with the prolonged use of isoflurane anesthesia. For each time point, measurements of perfusion, oxygen bioavailability and TRBF were acquired. Measurements of perfusion and oxygen bioavailability were compared with measurements of TRBF for all swine across all time points. Cortical perfusion, cortical oxygen bioavailability, medullary oxygen bioavailability and TRBF significantly increased with the acetylcholine challenge. Cortical perfusion, medullary perfusion, cortical oxygen bioavailability and TRBF significantly decreased during isoflurane anesthesia. Cortical perfusion (Spearman's correlation coefficient = 0.68; P renal function. Maintenance of the medullary oxygen bioavailability in low blood flow states may reflect the autoregulation particular to this region of the kidney. The ability to non-invasively measure all three parameters of kidney function in a single MRI examination and to evaluate the relationships between these functional parameters is potentially useful for evaluating the state of the human kidneys in situ in future studies.

  3. Acute effect of glucose on cerebral blood flow, blood oxygenation, and oxidative metabolism.

    Science.gov (United States)

    Xu, Feng; Liu, Peiying; Pascual, Juan M; Xiao, Guanghua; Huang, Hao; Lu, Hanzhang

    2015-02-01

    While it is known that specific nuclei of the brain, for example hypothalamus, contain glucose-sensing neurons thus their activity is affected by blood glucose level, the effect of glucose modulation on whole-brain metabolism is not completely understood. Several recent reports have elucidated the long-term impact of caloric restriction on the brain, showing that animals under caloric restriction had enhanced rate of tricarboxylic acid cycle (TCA) cycle flux accompanied by extended life span. However, acute effect of postprandial blood glucose increase has not been addressed in detail, partly due to a scarcity and complexity of measurement techniques. In this study, using a recently developed noninvasive MR technique, we measured dynamic changes in global cerebral metabolic rate of O2 (CMRO2 ) following a 50 g glucose ingestion (N = 10). A time dependent decrease in CMRO2 was observed, which was accompanied by a reduction in oxygen extraction fraction (OEF) with unaltered cerebral blood flow (CBF). At 40 min post-ingestion, the amount of CMRO2 reduction was 7.8 ± 1.6%. A control study without glucose ingestion was performed (N = 10), which revealed no changes in CMRO2 , CBF, or OEF, suggesting that the observations in the glucose study was not due to subject drowsiness or fatigue after staying inside the scanner. These findings suggest that ingestion of glucose may alter the rate of cerebral metabolism of oxygen in an acute setting. © 2014 Wiley Periodicals, Inc.

  4. MR-based methods of the functional imaging of the CNS; MR-basierte Methoden der funktionellen Bildgebung des zentralen Nervensystems

    Energy Technology Data Exchange (ETDEWEB)

    Giesel, F.L.; Weber, M.A.; Zechmann, C.; Tengg-Kobligk, H. von; Essig, M.; Kauczor, H.U. [Radiologie, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany); Wuestenberg, T. [Abt. fuer Medizinische Psychologie, Georg-August-Univ. Goettingen (Germany); Bongers, A.; Baudendistel, K.T. [Medizinische Physik in der Radiologie, Deutsches Krebsforschungszentrum (DKFZ), Heidelberg (Germany); Hahn, H.K. [MeVis, Zentrum fuer Medizinische Diagnosesysteme und Visualisierung, Bremen (Germany)

    2005-05-01

    This review presents the basic principles of functional imaging of the central nervous system utilizing magnetic resonance imaging. The focus is set on visualization of different functional aspects of the brain and related pathologies. Additionally, clinical cases are presented to illustrate the applications of functional imaging techniques in the clinical setting. The relevant physics and physiology of contrast-enhanced and non-contrast-enhanced methods are discussed. The two main functional MR techniques requiring contrast-enhancement are dynamic T1- and T2{sup *}-MRI to image perfusion. Based on different pharmacokinetic models of contrast enhancement diagnostic applications for neurology and radio-oncology are discussed. The functional non-contrast enhanced imaging techniques are based on ''blood oxygenation level dependent (BOLD)-fMRI and arterial spin labeling (ASL) technique. They have gained clinical impact particularly in the fields of psychiatry and neurosurgery. (orig.)

  5. Prevention of radiographic-contrast-agent-induced reductions in renal function by acetylcysteine

    DEFF Research Database (Denmark)

    Tepel, Martin; van der Giet, M; Schwarzfeld, C

    2000-01-01

    Radiographic contrast agents can cause a reduction in renal function that may be due to reactive oxygen species. Whether the reduction can be prevented by the administration of antioxidants is unknown.......Radiographic contrast agents can cause a reduction in renal function that may be due to reactive oxygen species. Whether the reduction can be prevented by the administration of antioxidants is unknown....

  6. DEPENDENCE OF THE SPECKLE-PATTERNS SIZE AND THEIR CONTRAST ON THE BIOPHYSICAL AND STRUCTURAL PARAMETERS OF BIOLOGICAL TISSUES

    Directory of Open Access Journals (Sweden)

    N. D. Abramovich

    2017-01-01

    Full Text Available Speckle fields are widely used in optical diagnostics of biotissues and evaluation of the functional state of bioobjects. The speckle field is formed by laser radiation scattered from the object under study. It bears information about the average dimensions of the scatterers, the degree of surface roughness makes it possible to judge the structural and biophysical characteristics of individual tissue cells (particles, on the one hand, and the integral optical characteristics of the entire biological tissue. The aim of the study was – the determination of connections between the biophysical and structural characteristics of the biotissue and the light fields inside the biotissues.The model developed of the medium gives a direct relationship between the optical and biophysical parameters of the biotissue. Calculations were carried out using known solutions of the radiation transfer equation, taking into account the multilayer structure of the tissue, multiple scattering in the medium, and multiple reflection of irradiation between the layers.With the increase wavelength, the size of speckles formed by the non-scattered component (direct light of laser radiation increases by a factor of 2 from 400 to 800 μm in the stratum corneum and 5 times from 0.6 to 3 μm for the epidermis and from 0.27 to 1.4 μm to the dermis. Typical values of sizes of speckles formed by the diffraction component of laser radiation for the stratum corneum and epidermis range from 0.02 to 0.15 μm. For the dermis typical spot sizes are up to 0.03 μm. The speckle-spot size of the diffusion component in the dermis can vary from ±10 % at 400 nm and up to ±23 % for 800 nm when the volume concentration of blood capillaries changes. Characteristic dependencies are obtained and biophysical factors associated with the volume concentration of blood and the degree of it’s oxygenation that affect the contrast of the speckle structure in the dermis are discussed.The of speckles

  7. The coupling of cerebral blood flow and oxygen metabolism with brain activation is similar for simple and complex stimuli in human primary visual cortex.

    Science.gov (United States)

    Griffeth, Valerie E M; Simon, Aaron B; Buxton, Richard B

    2015-01-01

    Quantitative functional MRI (fMRI) experiments to measure blood flow and oxygen metabolism coupling in the brain typically rely on simple repetitive stimuli. Here we compared such stimuli with a more naturalistic stimulus. Previous work on the primary visual cortex showed that direct attentional modulation evokes a blood flow (CBF) response with a relatively large oxygen metabolism (CMRO2) response in comparison to an unattended stimulus, which evokes a much smaller metabolic response relative to the flow response. We hypothesized that a similar effect would be associated with a more engaging stimulus, and tested this by measuring the primary human visual cortex response to two contrast levels of a radial flickering checkerboard in comparison to the response to free viewing of brief movie clips. We did not find a significant difference in the blood flow-metabolism coupling (n=%ΔCBF/%ΔCMRO2) between the movie stimulus and the flickering checkerboards employing two different analysis methods: a standard analysis using the Davis model and a new analysis using a heuristic model dependent only on measured quantities. This finding suggests that in the primary visual cortex a naturalistic stimulus (in comparison to a simple repetitive stimulus) is either not sufficient to provoke a change in flow-metabolism coupling by attentional modulation as hypothesized, that the experimental design disrupted the cognitive processes underlying the response to a more natural stimulus, or that the technique used is not sensitive enough to detect a small difference. Copyright © 2014 Elsevier Inc. All rights reserved.

  8. A theoretical framework for determining cerebral vascular function and heterogeneity from dynamic susceptibility contrast MRI.

    Science.gov (United States)

    Digernes, Ingrid; Bjørnerud, Atle; Vatnehol, Svein Are S; Løvland, Grete; Courivaud, Frédéric; Vik-Mo, Einar; Meling, Torstein R; Emblem, Kyrre E

    2017-06-01

    Mapping the complex heterogeneity of vascular tissue in the brain is important for understanding cerebrovascular disease. In this translational study, we build on previous work using vessel architectural imaging (VAI) and present a theoretical framework for determining cerebral vascular function and heterogeneity from dynamic susceptibility contrast magnetic resonance imaging (MRI). Our tissue model covers realistic structural architectures for vessel branching and orientations, as well as a range of hemodynamic scenarios for blood flow, capillary transit times and oxygenation. In a typical image voxel, our findings show that the apparent MRI relaxation rates are independent of the mean vessel orientation and that the vortex area, a VAI-based parameter, is determined by the relative oxygen saturation level and the vessel branching of the tissue. Finally, in both simulated and patient data, we show that the relative distributions of the vortex area parameter as a function of capillary transit times show unique characteristics in normal-appearing white and gray matter tissue, whereas tumour-voxels in comparison display a heterogeneous distribution. Collectively, our study presents a comprehensive framework that may serve as a roadmap for in vivo and per-voxel determination of vascular status and heterogeneity in cerebral tissue.

  9. Quantifying the microvascular origin of BOLD-fMRI from first principles with two-photon microscopy and an oxygen-sensitive nanoprobe.

    Science.gov (United States)

    Gagnon, Louis; Sakadžić, Sava; Lesage, Frédéric; Musacchia, Joseph J; Lefebvre, Joël; Fang, Qianqian; Yücel, Meryem A; Evans, Karleyton C; Mandeville, Emiri T; Cohen-Adad, Jülien; Polimeni, Jonathan R; Yaseen, Mohammad A; Lo, Eng H; Greve, Douglas N; Buxton, Richard B; Dale, Anders M; Devor, Anna; Boas, David A

    2015-02-25

    The blood oxygenation level-dependent (BOLD) contrast is widely used in functional magnetic resonance imaging (fMRI) studies aimed at investigating neuronal activity. However, the BOLD signal reflects changes in blood volume and oxygenation rather than neuronal activity per se. Therefore, understanding the transformation of microscopic vascular behavior into macroscopic BOLD signals is at the foundation of physiologically informed noninvasive neuroimaging. Here, we use oxygen-sensitive two-photon microscopy to measure the BOLD-relevant microvascular physiology occurring within a typical rodent fMRI voxel and predict the BOLD signal from first principles using those measurements. The predictive power of the approach is illustrated by quantifying variations in the BOLD signal induced by the morphological folding of the human cortex. This framework is then used to quantify the contribution of individual vascular compartments and other factors to the BOLD signal for different magnet strengths and pulse sequences. Copyright © 2015 the authors 0270-6474/15/353663-13$15.00/0.

  10. Effect of hypoxia on BOLD fMRI response and total cerebral blood flow in migraine with aura patients

    DEFF Research Database (Denmark)

    Arngrim, Nanna; Hougaard, Anders; Schytz, Henrik W

    2018-01-01

    was measured in the visual cortex ROIs V1-V5. Total cerebral blood flow (CBF) was calculated by measuring the blood velocity in the internal carotid arteries and the basilar artery using phase-contrast mapping (PCM) MRI. Hypoxia induced a greater decrease in BOLD response to visual stimulation in V1-V4 in MA......Experimentally induced hypoxia triggers migraine and aura attacks in patients suffering from migraine with aura (MA). We investigated the blood oxygenation level-dependent (BOLD) signal response to visual stimulation during hypoxia in MA patients and healthy volunteers. In a randomized double......-blind crossover study design, 15 MA patients were allocated to 180 min of normobaric poikilocapnic hypoxia (capillary oxygen saturation 70-75%) or sham (normoxia) on two separate days and 14 healthy volunteers were exposed to hypoxia. The BOLD functional MRI (fMRI) signal response to visual stimulation...

  11. Changes in Oxygen Partial Pressure in the Vitreous Body and Arterial Blood of Rabbits Depending on Oxygen Concentration in Inspired Mixture.

    Science.gov (United States)

    Amkhanitskaya, L I; Nikolaeva, G V; Sokolova, N A

    2015-07-01

    We demonstrated that the vitreous body of one-month-old rabbits becomes a "reservoir" for storage and accumulation of oxygen after exposure to additional oxygenation of the organism (O2 concentrations in inspired gas mixture were 40, 60, 85, and 99%). The higher was O2 concentration in inspired mixture, the higher was oxygen saturation of the blood and vitreous body. O2 concentration of 40% was relatively safe for eye tissues. O2 concentration >60% induced oxygen accumulation in the vitreous body, which can be a provoking factor for the development of oxygen-induced pathologies.

  12. Advantages of frequency-domain modeling in dynamic-susceptibility contrast magnetic resonance cerebral blood flow quantification.

    Science.gov (United States)

    Chen, Jean J; Smith, Michael R; Frayne, Richard

    2005-03-01

    In dynamic-susceptibility contrast magnetic resonance perfusion imaging, the cerebral blood flow (CBF) is estimated from the tissue residue function obtained through deconvolution of the contrast concentration functions. However, the reliability of CBF estimates obtained by deconvolution is sensitive to various distortions including high-frequency noise amplification. The frequency-domain Fourier transform-based and the time-domain singular-value decomposition-based (SVD) algorithms both have biases introduced into their CBF estimates when noise stability criteria are applied or when contrast recirculation is present. The recovery of the desired signal components from amid these distortions by modeling the residue function in the frequency domain is demonstrated. The basic advantages and applicability of the frequency-domain modeling concept are explored through a simple frequency-domain Lorentzian model (FDLM); with results compared to standard SVD-based approaches. The performance of the FDLM method is model dependent, well representing residue functions in the exponential family while less accurately representing other functions. (c) 2005 Wiley-Liss, Inc.

  13. Blood oxygen depletion is independent of dive function in a deep diving vertebrate, the northern elephant seal.

    Directory of Open Access Journals (Sweden)

    Jessica U Meir

    Full Text Available Although energetics is fundamental to animal ecology, traditional methods of determining metabolic rate are neither direct nor instantaneous. Recently, continuous blood oxygen (O2 measurements were used to assess energy expenditure in diving elephant seals (Mirounga angustirostris, demonstrating that an exceptional hypoxemic tolerance and exquisite management of blood O2 stores underlie the extraordinary diving capability of this consummate diver. As the detailed relationship of energy expenditure and dive behavior remains unknown, we integrated behavior, ecology, and physiology to characterize the costs of different types of dives of elephant seals. Elephant seal dive profiles were analyzed and O2 utilization was classified according to dive type (overall function of dive: transit, foraging, food processing/rest. This is the first account linking behavior at this level with in vivo blood O2 measurements in an animal freely diving at sea, allowing us to assess patterns of O2 utilization and energy expenditure between various behaviors and activities in an animal in the wild. In routine dives of elephant seals, the blood O2 store was significantly depleted to a similar range irrespective of dive function, suggesting that all dive types have equal costs in terms of blood O2 depletion. Here, we present the first physiological evidence that all dive types have similarly high blood O2 demands, supporting an energy balance strategy achieved by devoting one major task to a given dive, thereby separating dive functions into distinct dive types. This strategy may optimize O2 store utilization and recovery, consequently maximizing time underwater and allowing these animals to take full advantage of their underwater resources. This approach may be important to optimizing energy expenditure throughout a dive bout or at-sea foraging trip and is well suited to the lifestyle of an elephant seal, which spends > 90% of its time at sea submerged making diving its

  14. Monitoring of blood oxygenation in brain by resonance Raman spectroscopy

    DEFF Research Database (Denmark)

    Brazhe, Nadezda A; Thomsen, Kirsten; Lønstrup, Micael

    2018-01-01

    Blood oxygenation in cerebral vessels is an essential parameter to evaluate brain function and to investigate the coupling between local blood flow and neuronal activity. We apply resonance Raman spectroscopy in vivo to study hemoglobin oxygenation in cortex vessels of anesthetized ventilated mice....... We demonstrate that the pairs of Raman peaks at 1355 and1375 cm-1(symmetric vibrations of pyrrol half-rings in the heme molecule), 1552 and 1585 cm-1and 1602 and 1638 cm-1(vibrations of methine bridges in heme molecule) are reliable markers for quantitative estimation of the relative amount...

  15. Optoacoustic measurements of human placenta and umbilical blood oxygenation

    Science.gov (United States)

    Nanovskaya, T. N.; Petrov, I. Y.; Petrov, Y.; Patrikeeva, S. L.; Ahmed, M. S.; Hankins, G. D. V.; Prough, D. S.; Esenaliev, R. O.

    2016-03-01

    Adequate oxygenation is essential for normal embryogenesis and fetal growth. Perturbations in the intrauterine oxidative environment during pregnancy are associated with several pathophysiological disorders such as pregnancy loss, preeclampsia, and intrauterine growth restriction. We proposed to use optoacoustic technology for monitoring placental and fetal umbilical blood oxygenation. In this work, we studied optoacoustic monitoring of oxygenation in placenta and umbilical cord blood ex vivo using technique of placenta perfusion. We used a medical grade, nearinfrared, tunable, optoacoustic system developed and built for oxygenation monitoring in blood vessels and in tissues. First, we calibrated the system for cord blood oxygenation measurements by using a CO-Oximeter (gold standard). Then we performed validation in cord blood circulating through the catheters localized on the fetal side of an isolated placental lobule. Finally, the oxygenation measurements were performed in the perfused placental tissue. To increase or decrease blood oxygenation, we used infusion of a gas mixture of 95% O2 + 5% CO2 and 95% N2 + 5% CO2, respectively. In placental tissue, up to four cycles of changes in oxygenation were performed. The optoacoustically measured oxygenation in circulating cord blood and in placental lobule closely correlated with the actual oxygenation data measured by CO-Oximeter. We plan to further test the placental and cord blood oxygenation monitoring with optoacoustics in animal and clinical studies.

  16. MR Imaging-derived Oxygen-Hemoglobin Dissociation Curves and Fetal-Placental Oxygen-Hemoglobin Affinities.

    Science.gov (United States)

    Avni, Reut; Golani, Ofra; Akselrod-Ballin, Ayelet; Cohen, Yonni; Biton, Inbal; Garbow, Joel R; Neeman, Michal

    2016-07-01

    Purpose To generate magnetic resonance (MR) imaging-derived, oxygen-hemoglobin dissociation curves and to map fetal-placental oxygen-hemoglobin affinity in pregnant mice noninvasively by combining blood oxygen level-dependent (BOLD) T2* and oxygen-weighted T1 contrast mechanisms under different respiration challenges. Materials and Methods All procedures were approved by the Weizmann Institutional Animal Care and Use Committee. Pregnant mice were analyzed with MR imaging at 9.4 T on embryonic days 14.5 (eight dams and 58 fetuses; imprinting control region ICR strain) and 17.5 (21 dams and 158 fetuses) under respiration challenges ranging from hyperoxia to hypoxia (10 levels of oxygenation, 100%-10%; total imaging time, 100 minutes). A shorter protocol with normoxia to hyperoxia was also performed (five levels of oxygenation, 20%-100%; total imaging time, 60 minutes). Fast spin-echo anatomic images were obtained, followed by sequential acquisition of three-dimensional gradient-echo T2*- and T1-weighted images. Automated registration was applied to align regions of interest of the entire placenta, fetal liver, and maternal liver. Results were compared by using a two-tailed unpaired Student t test. R1 and R2* values were derived for each tissue. MR imaging-based oxygen-hemoglobin dissociation curves were constructed by nonlinear least square fitting of 1 minus the change in R2*divided by R2*at baseline as a function of R1 to a sigmoid-shaped curve. The apparent P50 (oxygen tension at which hemoglobin is 50% saturated) value was derived from the curves, calculated as the R1 scaled value (x) at which the change in R2* divided by R2*at baseline scaled (y) equals 0.5. Results The apparent P50 values were significantly lower in fetal liver than in maternal liver for both gestation stages (day 14.5: 21% ± 5 [P = .04] and day 17.5: 41% ± 7 [P hemoglobin dissociation curves with a shorter protocol that excluded the hypoxic periods was demonstrated. Conclusion MR imaging

  17. Density functional theory study the effects of oxygen-containing functional groups on oxygen molecules and oxygen atoms adsorbed on carbonaceous materials.

    Science.gov (United States)

    Qi, Xuejun; Song, Wenwu; Shi, Jianwei

    2017-01-01

    Density functional theory was used to study the effects of different types of oxygen-containing functional groups on the adsorption of oxygen molecules and single active oxygen atoms on carbonaceous materials. During gasification or combustion reactions of carbonaceous materials, oxygen-containing functional groups such as hydroxyl(-OH), carbonyl(-CO), quinone(-O), and carboxyl(-COOH) are often present on the edge of graphite and can affect graphite's chemical properties. When oxygen-containing functional groups appear on a graphite surface, the oxygen molecules are strongly adsorbed onto the surface to form a four-member ring structure. At the same time, the O-O bond is greatly weakened and easily broken. The adsorption energy value indicates that the adsorption of oxygen molecules changes from physisorption to chemisorption for oxygen-containing functional groups on the edge of a graphite surface. In addition, our results indicate that the adsorption energy depends on the type of oxygen-containing functional group. When a single active oxygen atom is adsorbed on the bridge site of graphite, it gives rise to a stable epoxy structure. Epoxy can cause deformation of the graphite lattice due to the transition of graphite from sp2 to sp3 after the addition of an oxygen atom. For quinone group on the edge of graphite, oxygen atoms react with carbon atoms to form the precursor of CO2. Similarly, the single active oxygen atoms of carbonyl groups can interact with edge carbon atoms to form the precursor of CO2. The results show that oxygen-containing functional groups on graphite surfaces enhance the activity of graphite, which promotes adsorption on the graphite surface.

  18. Spatio-temporal cerebral blood flow perfusion patterns in cortical spreading depression

    Science.gov (United States)

    Verisokin, Andrey Yu.; Verveyko, Darya V.; Postnov, Dmitry E.

    2017-04-01

    Cortical spreading depression (CSD) is an example of one of the most common abnormalities in biophysical brain functioning. Despite the fact that there are many mathematical models describing the cortical spreading depression (CSD), most of them do not take into consideration the role of redistribution of cerebral blood flow (CBF), that results in the formation of spatio-temporal patterns. The paper presents a mathematical model, which successfully explains the CBD role in the CSD process. Numerical study of this model has revealed the formation of stationary dissipative structures, visually analogous to Turing structures. However, the mechanism of their formation is not diffusion. We show these structures occur due to another type of spatial coupling, that is related to tissue perfusion rate. The proposed model predicts that at similar state of neurons the distribution of blood flow and oxygenation may by different. Currently, this effect is not taken into account when the Blood oxygen-level dependent (BOLD) contrast imaging used in functional magnetic resonance imaging (fMRI). Thus, the diagnosis on the BOLD signal can be ambiguous. We believe that our results can be used in the future for a more correct interpretation of the data obtained with fMRI, NIRS and other similar methods for research of the brain activity.

  19. Capillary-oxygenation-level-dependent near-infrared spectrometry in frontal lobe of humans

    NARCIS (Netherlands)

    Rasmussen, Peter; Dawson, Ellen A.; Nybo, Lars; van Lieshout, Johannes J.; Secher, Niels H.; Gjedde, Albert

    2007-01-01

    Brain function requires oxygen and maintenance of brain capillary oxygenation is important. We evaluated how faithfully frontal lobe near-infrared spectroscopy (NIRS) follows haemoglobin saturation (SCap) and how calculated mitochondrial oxygen tension (PMitoO2) influences motor performance. Twelve

  20. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    Energy Technology Data Exchange (ETDEWEB)

    Clanet, M

    1987-06-18

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO/sub 2/), oxygen extraction (EO/sub 2/) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO/sub 2/ and often a decrease in CMRO/sub 2/, whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO/sub 2/, EO/sub 2/ and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis.

  1. Value of cerebral blood flow rate and regional oxygen consumption studies in cerebral ischaemia

    International Nuclear Information System (INIS)

    Clanet, M.

    1987-01-01

    Studies of experimentally-induced ischaemia have shown that the intensity of neuronal suffering is related to the fall in perfusion rate. Below a certain level, called functional threshold, cerebral function is reversibly altered, whereas at a lower level (tissue necrosis threshold) the damage inflicted on neurons is irreversible. Between these two thresholds lies a ''penumbra zone''. This concept of thresholds must be mitigated by 2 parameters: duration of ischaemia and selective vulnerability of the various structures affected. Variations in blood flow rate only indirectly affect the state of tissues. Techniques developed from positron emission tomography make it possible to evaluate the metabolic activity of brain tissue in vivo: oxygen consumption (CMRO 2 ), oxygen extraction (EO 2 ) and glucose consumption (CMRG) which are thus correlated to cerebral blood flow and cerebral blood volume, sometimes also to tissue pH. Normal relations between blood flow rate and metabolism may be altered. Misery perfusion reflects a fall in cerebral blood flow with an increase in EO 2 and often a decrease in CMRO 2 , whereas luxury perfusion reflects an increase in cerebral blood flow rate with reduction of CMRO 2 , EO 2 and CMRG. The type of alteration encountered in human ischaemia varies according to the nature of the accident: studies of transient accidents emphasize the different haemodynamic aspects of occlusion of the wider arteries. The metabolic and haemodynamic profiles of established ischaemic accidents vary according to their type and to the time of the study, reflecting the complexity of the physiopathological mechanisms involved; they are frequently associated with metabolic repercussions at a distance from the ischaemic focus, which supports the concept of diaschisis [fr

  2. Oxygen Therapy

    Directory of Open Access Journals (Sweden)

    Bonnie Solmes

    2000-01-01

    Full Text Available LTOT is prescribed for people with chronic lung disease in whom there is a decrease in the ability of the lungs to supply enough oxygen to the body. The heart is obliged to pump faster to meet the body's oxygen requirements. This may place undue stress on the heart, resulting in palpitations, dizziness and fatigue. A low oxygen level in arterial blood is also harmful to the heart, the brain and the pulmonary blood vessels. Oxygen therapy is used to break this cycle. A person with low blood oxygen will often be able to accomplish more with less fatigue with the help of supplemental oxygen therapy. Shortness of breath is a mechanical problem resulting from the effects of chronic obstructive pulmonary disease. Oxygen therapy may or may not reduce shortness of breath, but it will help the lungs and heart to function with less stress.

  3. In contrast to BOLD: signal enhancement by extravascular water protons as an alternative mechanism of endogenous fMRI signal change.

    Science.gov (United States)

    Figley, Chase R; Leitch, Jordan K; Stroman, Patrick W

    2010-10-01

    Despite the popularity and widespread application of functional magnetic resonance imaging (fMRI) in recent years, the physiological bases of signal change are not yet fully understood. Blood oxygen level-dependant (BOLD) contrast - attributed to local changes in blood flow and oxygenation, and therefore magnetic susceptibility - has become the most prevalent means of functional neuroimaging. However, at short echo times, spin-echo sequences show considerable deviations from the BOLD model, implying a second, non-BOLD component of signal change. This has been dubbed "signal enhancement by extravascular water protons" (SEEP) and is proposed to result from proton-density changes associated with cellular swelling. Given that such changes are independent of magnetic susceptibility, SEEP may offer new and improved opportunities for carrying out fMRI in regions with close proximity to air-tissue and/or bone-tissue interfaces (e.g., the prefrontal cortex and spinal cord), as well as regions close to large blood vessels, which may not be ideally suited for BOLD imaging. However, because of the interdisciplinary nature of the literature, there has yet to be a thorough synthesis, tying together the various and sometimes disparate aspects of SEEP theory. As such, we aim to provide a concise yet comprehensive overview of SEEP, including recent and compelling evidence for its validity, its current applications and its future relevance to the rapidly expanding field of functional neuroimaging. Before presenting the evidence for a non-BOLD component of endogenous functional contrast, and to enable a more critical review for the nonexpert reader, we begin by reviewing the fundamental principles underlying BOLD theory. Copyright © 2010 Elsevier Inc. All rights reserved.

  4. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-01

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  5. Eigenspectra optoacoustic tomography achieves quantitative blood oxygenation imaging deep in tissues.

    Science.gov (United States)

    Tzoumas, Stratis; Nunes, Antonio; Olefir, Ivan; Stangl, Stefan; Symvoulidis, Panagiotis; Glasl, Sarah; Bayer, Christine; Multhoff, Gabriele; Ntziachristos, Vasilis

    2016-06-30

    Light propagating in tissue attains a spectrum that varies with location due to wavelength-dependent fluence attenuation, an effect that causes spectral corruption. Spectral corruption has limited the quantification accuracy of optical and optoacoustic spectroscopic methods, and impeded the goal of imaging blood oxygen saturation (sO2) deep in tissues; a critical goal for the assessment of oxygenation in physiological processes and disease. Here we describe light fluence in the spectral domain and introduce eigenspectra multispectral optoacoustic tomography (eMSOT) to account for wavelength-dependent light attenuation, and estimate blood sO2 within deep tissue. We validate eMSOT in simulations, phantoms and animal measurements and spatially resolve sO2 in muscle and tumours, validating our measurements with histology data. eMSOT shows substantial sO2 accuracy enhancement over previous optoacoustic methods, potentially serving as a valuable tool for imaging tissue pathophysiology.

  6. Self-Assembled Nanomicelles as MRI Blood-Pool Contrast Agent.

    Science.gov (United States)

    Babič, Andrej; Vorobiev, Vassily; Xayaphoummine, Céline; Lapicorey, Gaëlle; Chauvin, Anne-Sophie; Helm, Lothar; Allémann, Eric

    2018-01-26

    Gadolinium-loaded nanomicelles show promise as future magnetic resonance imaging (MRI) contrast agents (CAs). Their increased size and high gadolinium (Gd) loading gives them an edge in proton relaxivity over smaller molecular Gd-complexes. Their size and stealth properties are fundamental for their long blood residence time, opening the possibility for use as blood-pool contrast agents. Using l-tyrosine as a three-functional scaffold we synthesized a nanostructure building block 8. The double C18 aliphatic chain on one side, Gd-1,4,7,10-tetraazacyclododecane-1-4-7-triacetic acid (Gd-DO3A) with access to bulk water in the center and 2 kDa PEG on the hydrophilic side gave the amphiphilic properties required for the core-shell nanomicellar architecture. The self-assembly into Gd-loaded monodispersed 10-20 nm nanomicelles occurred spontaneously in water. These nanomicelles (Tyr-MRI) display very high relaxivity at 29 mm -1  s -1 at low field strength and low cytotoxicity. Good contrast enhancement of the blood vessels and the heart together with prolonged circulation time in vivo, makes Tyr-MRI an excellent candidate for a new supramolecular blood-pool MRI CA. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Functional magnetic resonance imaging of the frontal eye fields during saccadic eye movements

    International Nuclear Information System (INIS)

    Miki, Atsushi; Takagi, Mineo; Abe, Haruki; Nakajima, Takashi; Miyauchi, Satoru.

    1996-01-01

    We evaluated activity-induced signal intensity changes in the human cerebral cortex during horizontal saccadic eye movements using functional magnetic resonance imaging (fMRI) based on the blood-oxygenation-level-dependent (BOLD) contrast method. Compared with central fixation, significant signal increases were observed bilaterally in the middle frontal gyrus (Brodmann area 8) during saccadic conditions. The location of the activated area was consistent with that of previously reported frontal eye fields (FEF). These results suggest that fMRI has potential merit for the study of cortical control of eye movements in humans. (author)

  8. Functional magnetic resonance imaging of the primary motor cortex ...

    Indian Academy of Sciences (India)

    Unknown

    Abbreviations used: BOLD, Blood oxygenation level dependent; CBF, cerebral blood flow; fMRI, functional magnetic resonance imaging; EPI, eco-planar imaging; FOV, field of view; MRI, Magnetic resonance imaging; MRS, magnetic resonance spectroscopy;. PET, position emission tomography; rCBF, regional cerebral ...

  9. Replacing the Transfusion of 1–2 Units of Blood with Plasma Expanders that Increase Oxygen Delivery Capacity: Evidence from Experimental Studies

    Directory of Open Access Journals (Sweden)

    Amy G. Tsai

    2014-10-01

    Full Text Available At least a third of the blood supply in the world is used to transfuse 1–2 units of packed red blood cells for each intervention and most clinical trials of blood substitutes have been carried out at this level of oxygen carrying capacity (OCC restoration. However, the increase of oxygenation achieved is marginal or none at all for molecular hemoglobin (Hb products, due to their lingering vasoactivity. This has provided the impetus for the development of “oxygen therapeutics” using Hb-based molecules that have high oxygen affinity and target delivery of oxygen to anoxic areas. However it is still unclear how these oxygen carriers counteract or mitigate the functional effects of anemia due to obstruction, vasoconstriction and under-perfusion. Indeed, they are administered as a low dosage/low volume therapeutic Hb (subsequently further diluted in the circulatory pool and hence induce extremely small OCC changes. Hyperviscous plasma expanders provide an alternative to oxygen therapeutics by increasing the oxygen delivery capacity (ODC; in anemia they induce supra-perfusion and increase tissue perfusion (flow by as much as 50%. Polyethylene glycol conjugate albumin (PEG-Alb accomplishes this by enhancing the shear thinning behavior of diluted blood, which increases microvascular endothelial shear stress, causes vasodilation and lowering peripheral vascular resistance thus facilitating cardiac function. Induction of supra-perfusion takes advantage of the fact that ODC is the product of OCC and blood flow and hence can be maintained by increasing either or both. Animal studies suggest that this approach may save a considerable fraction of the blood supply. It has an additional benefit of enhancing tissue clearance of toxic metabolites.

  10. Myocardial blood flow and its transit time, oxygen utilization, and efficiency of highly endurance-trained human heart.

    Science.gov (United States)

    Heinonen, Ilkka; Kudomi, Nobuyuki; Kemppainen, Jukka; Kiviniemi, Antti; Noponen, Tommi; Luotolahti, Matti; Luoto, Pauliina; Oikonen, Vesa; Sipilä, Hannu T; Kopra, Jaakko; Mononen, Ilkka; Duncker, Dirk J; Knuuti, Juhani; Kalliokoski, Kari K

    2014-07-01

    Highly endurance-trained athlete's heart represents the most extreme form of cardiac adaptation to physical stress, but its circulatory alterations remain obscure. In the present study, myocardial blood flow (MBF), blood mean transit time (MTT), oxygen extraction fraction (OEF) and consumption (MVO2), and efficiency of cardiac work were quantified in highly trained male endurance athletes and control subjects at rest and during supine cycling exercise using [(15)O]-labeled radiotracers and positron emission tomography. Heart rate and MBF were lower in athletes both at rest and during exercise. OEF increased in response to exercise in both groups, but was higher in athletes (70 ± 21 vs. 63 ± 11 % at rest and 86 ± 13 vs. 73 ± 10 % during exercise). MTT was longer and vascular resistance higher in athletes both at rest and during exercise, but arterial content of 2,3-diphosphoglycerate (oxygen affinity) was unchanged. MVO2 per gram of myocardium trended (p = 0.08) lower in athletes both at rest and during exercise, while myocardial efficiency of work and MVO2 per beat were not different between groups. Arterial levels of free fatty acids were ~twofold higher in athletes likely leading to higher myocardial fatty acid oxidation and hence oxygen cost, which may have blunted the bradycardia-induced decrease in MVO2. Finally, the observed group differences in MBF, OEF, MTT and vascular resistance remained significant also after they were controlled for differences in MVO2. In conclusion, in highly endurance-trained human heart, increased myocardial blood transition time enables higher oxygen extraction levels with a lower myocardial blood flow and higher vascular resistance. These physiological adaptations to exercise training occur independently of the level of oxygen consumption and together with training-induced bradycardia may serve as mechanisms to increase functional reserve of the human heart.

  11. [Functional magnetic resonance imaging in psychiatry and psychotherapy].

    Science.gov (United States)

    Derntl, B; Habel, U; Schneider, F

    2010-01-01

    technical improvements, functional magnetic resonance imaging (fMRI) has become the most popular and versatile imaging method in psychiatric research. The scope of this manuscript is to briefly introduce the basics of MR physics, the blood oxygenation level-dependent (BOLD) contrast as well as the principles of MR study design and functional data analysis. The presentation of exemplary studies on emotion recognition and empathy in schizophrenia patients will highlight the importance of MR methods in psychiatry. Finally, we will demonstrate insights into new developments that will further boost MR techniques in clinical research and will help to gain more insight into dysfunctional neural networks underlying cognitive and emotional deficits in psychiatric patients. Moreover, some techniques such as neurofeedback seem promising for evaluation of therapy effects on a behavioral and neural level.

  12. Toe blood pressure and leg muscle oxygenation with body posture.

    Science.gov (United States)

    Rosales-Velderrain, Armando; Cardno, Michael; Mateus, Jaime; Kumar, Ravindra; Schlabs, Thomas; Hargens, Alan R

    2011-05-01

    In 1980 Katkov and Chestukhin measured blood pressures and oxygenation invasively at various body tilt angles at different locations on the body, including the foot. To our knowledge, such measurements have not been performed noninvasively. Therefore, the purpose of this study was to measure toe blood pressure (TBP) and lower limb muscle oxygenation noninvasively at various body tilt angles, and to assess the use of a Finometer for noninvasive TBP measurements. Our noninvasive results are compared with those performed by Katkov and Chestukhin. We hypothesized that: 1) the Finometer provides a noninvasive measurement of TBP at different tilt angles; and 2) muscle oxygenation is highest with 0 and -6 degrees, and decreases with increased head-up tilt (HUT). There were 10 subjects who were exposed to different body tilt angles (-6, 0, 10, 30, 70, and 90 degrees). At each angle we measured TBP noninvasively with a Finometer and muscle tissue oxygenation by near infrared spectroscopy. We found a strong correlation between TBP using the Finometer and TBP predicted by adding the hydrostatic component due to body tilt to the standard arm blood pressure measurement. At 10, 30, 70, and 90 degrees both TBP and tissue oxygenation were significantly different from the 0 degree (supine) level. Oxygenation decreased and TBP increased with higher HUT angles. No differences were observed in TBP or oxygenation between -6 and 0 degree. The Finometer accurately measures TBP noninvasively with body tilt. Also, muscle oxygenation is highest at small HUT angles and decreases with increased HUT.

  13. Correlation analysis between bone density measured by quantitative CT and blood sugar level of aged patients with non-insulin-dependent diabetes mellitus

    International Nuclear Information System (INIS)

    Wang Guizhi; Liang Ping; Qiao Junhua; Liu Chunyan

    2008-01-01

    Objective: To approach the correlation between the bone density measured by quantitative CT and the blood sugar level of the aged patients with non-insulin-dependent diabetes mellitus, and observe the effects of the blood sugar level on the bone density. Methods: The lumbar bone densities and the blood sugar levels of 160 aged patients with non-insulin-dependent diabetes mellitus (hyperglycemia group 80 cases, euglycemia group 80 cases ) and the healthy aged people (80 cases) were detected by quantitative CT and serum biochemical detection; the correlation between the blood sugar level and the bone density and the osteoporosis occurrence status of aged people in various groups were analyzed. Results: The bone density in the non-insulin-dependent diabetes and hyperglycemia group was lower than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); the morbility of osteoporosis in the non-insulin-dependent diabetes and hyperglycemia group was higher than those in normal (control) group and non-insulin-dependent diabetes and euglycemia group (P<0.05); negative correlation was found between the bone density and the blood sugar level (aged male group: r=-0.7382, P=0.0013; aged female group: r=-0.8343, P=0.0007). Conclusion: The blood sugar level affects the bone density of the aged patients with non-insulin-dependent diabetes mellitus; the higher the blood sugar level, the lower the bone density. The non-insulin-dependent diabetes aged patients with hyperglycemia have the liability of osteoporosis. (authors)

  14. Correlation between Oxygen Saturation and Hemoglobin and Hematokrit Levels in Tetralogy of Fallot Patients

    Directory of Open Access Journals (Sweden)

    Farhatul Inayah Adiputri

    2016-03-01

    Full Text Available Background: Hemoglobin and hematocrit levels increase in Tetralogy of Fallot (TOF but the oxygen saturation declines. Reduced hemoglobin in circulating blood as a parameter of cyanosis does not indicate rising hemoglobin due to the ‘not-working’ hemoglobins that affect the oxygen saturation. Increasing hematocrit is the result of secondary erythrocytosis caused by declining oxygen level in blood, which is related to the oxygen saturation. This study was conducted to find the correlation between oxygen saturation and hemoglobin and hematocrite levels in TOF patients. Methods: This study was undertaken at Dr. Hasan Sadikin General Hospital in the period of January 2011 to December 2012 using the cross-sectional analytic method with total sampling technique. Inclusion criteria were medical records of TOF patients diagnosed based on echocardiography that included data on oxygen saturation, hemoglobin, and hematocrite. Exclusion criteria was the history of red blood transfusion. Results: Thirty medical records of TOF patiens from Dr. Hasan Sadikin General Hospital Bandung were included in this study. Due to skewed data distribution, Spearman correlation test was used to analyze the data. There was a significant negative correlation between oxygen saturation and hematocrit level (r= -0.412; p=0.024 and insignificant correlation between oxygen saturation and hemoglobin (r=-0.329; p= 0.076. Conclusions: There is a weak negative correlation between oxygen saturation and hematocrite levels

  15. Regional cerebral blood flow and oxygen consumption during normal human sleep

    International Nuclear Information System (INIS)

    Takahashi, Ken

    1989-01-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO 2 ) were measured using the continuous inhalation technique for 15 O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. 15 O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO 2 . PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of 15 O gas, the 15 O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm 3 , were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO 2 were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO 2 were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO 2 during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author)

  16. Laminar microvascular transit time distribution in the mouse somatosensory cortex revealed by Dynamic Contrast Optical Coherence Tomography.

    Science.gov (United States)

    Merkle, Conrad W; Srinivasan, Vivek J

    2016-01-15

    The transit time distribution of blood through the cerebral microvasculature both constrains oxygen delivery and governs the kinetics of neuroimaging signals such as blood-oxygen-level-dependent functional Magnetic Resonance Imaging (BOLD fMRI). However, in spite of its importance, capillary transit time distribution has been challenging to quantify comprehensively and efficiently at the microscopic level. Here, we introduce a method, called Dynamic Contrast Optical Coherence Tomography (DyC-OCT), based on dynamic cross-sectional OCT imaging of an intravascular tracer as it passes through the field-of-view. Quantitative transit time metrics are derived from temporal analysis of the dynamic scattering signal, closely related to tracer concentration. Since DyC-OCT does not require calibration of the optical focus, quantitative accuracy is achieved even deep in highly scattering brain tissue where the focal spot degrades. After direct validation of DyC-OCT against dilution curves measured using a fluorescent plasma label in surface pial vessels, we used DyC-OCT to investigate the transit time distribution in microvasculature across the entire depth of the mouse somatosensory cortex. Laminar trends were identified, with earlier transit times and less heterogeneity in the middle cortical layers. The early transit times in the middle cortical layers may explain, at least in part, the early BOLD fMRI onset times observed in these layers. The layer-dependencies in heterogeneity may help explain how a single vascular supply manages to deliver oxygen to individual cortical layers with diverse metabolic needs. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Oxygen transport and cardiovascular function at extreme altitude: lessons from Operation Everest II

    Science.gov (United States)

    Sutton, J. R.; Reeves, J. T.; Groves, B. M.; Wagner, P. D.; Alexander, J. K.; Hultgren, H. N.; Cymerman, A.; Houston, C. S.

    1992-01-01

    Operation Everest II was designed to examine the physiological responses to gradual decompression simulating an ascent of Mt Everest (8,848 m) to an inspired PO2 of 43 mmHg. The principal studies conducted were cardiovascular, respiratory, muscular-skeletal and metabolic responses to exercise. Eight healthy males aged 21-31 years began the "ascent" and six successfully reached the "summit", where their resting arterial blood gases were PO2 = 30 mmHg and PCO2 = 11 mmHg, pH = 7.56. Their maximal oxygen uptake decreased from 3.98 +/- 0.2 L/min at sea level to 1.17 +/- 0.08 L/min at PIO2 43 mmHg. The principal factors responsible for oxygen transport from the atmosphere to tissues were (1) Alveolar ventilation--a four fold increase. (2) Diffusion from the alveolus to end capillary blood--unchanged. (3) Cardiac function (assessed by hemodynamics, echocardiography and electrocardiography)--normal--although maximum cardiac output and heart rate were reduced. (4) Oxygen extraction--maximal with PvO2 14.8 +/- 1 mmHg. With increasing altitude maximal blood and muscle lactate progressively declined although at any submaximal intensity blood and muscle lactate was higher at higher altitudes.

  18. TRANSFUSION RESTORES BLOOD VISCOSITY AND REINSTATES MICROVASCULAR CONDITIONS FROM HEMORRHAGIC SHOCK INDEPENDENT OF OXYGEN CARRYING CAPACITY

    OpenAIRE

    Cabrales, Pedro; Intaglietta, Marcos; Tsai, Amy G.

    2007-01-01

    Systemic and microvascular hemodynamic responses to transfusion of oxygen using functional and non-functional packed fresh red blood cells (RBCs) from hemorrhagic shock were studied in the hamster window chamber model to determine the significance of RBCs on rheological and oxygen transport properties. Moderate hemorrhagic shock was induced by arterial controlled bleeding of 50% of the blood volume, and a hypovolemic state was maintained for one hour. Volume restitution was performed by infus...

  19. Blood hemoglobin level and treatment outcome of early breast cancer

    International Nuclear Information System (INIS)

    Henke, M.; Sindlinger, F.; Ikenberg, H.; Gerds, T.; Schumacher, M.

    2004-01-01

    Background and purpose: to determine whether the blood hemoglobin concentration correlates with the prognosis of patients with early breast cancer and, if so, whether this is restricted to treatment modality. Patients and methods: data were collected retrospectively from patients with early breast cancer (T1,2 NO-2 MO) who underwent either breast-conserving surgery followed by adjuvant radiotherapy (BCS-RT; n = 96) or a modified radical mastectomy (MRM; n = 194). The effect of preoperative blood hemoglobin level, nodal status, histological grading and hormone receptor status on disease-free survival was determined for both treatment modalities using a cox regression model and visualized by kaplan-meier plots. Results: the blood hemoglobin concentration significantly correlated with disease-free survival of patients receiving BCS-RT (relative risk [RR]: 0.67 per g/dl; p = 0.007). This was independent of other known risk factors for breast cancer patients, as determined by multivariate analysis. By contrast, the blood hemoglobin level had no prognostic significance when patients were treated with MRM. Conclusion: blood hemoglobin concentration seems to affect the prognosis of patients with early breast cancer when a treatment schedule that includes radiotherapy is applied. Reduced radiosensitivity due to diminished tumor oxygenation may be the underlying cause. Confirmative trials and studies intended to elucidate the underlying mechanism are warranted. (orig.)

  20. Incorporating Oxygen-Enhanced MRI into Multi-Parametric Assessment of Human Prostate Cancer

    Directory of Open Access Journals (Sweden)

    Heling Zhou

    2017-08-01

    Full Text Available Hypoxia is associated with prostate tumor aggressiveness, local recurrence, and biochemical failure. Magnetic resonance imaging (MRI offers insight into tumor pathophysiology and recent reports have related transverse relaxation rate (R2* and longitudinal relaxation rate (R1 measurements to tumor hypoxia. We have investigated the inclusion of oxygen-enhanced MRI for multi-parametric evaluation of tumor malignancy. Multi-parametric MRI sequences at 3 Tesla were evaluated in 10 patients to investigate hypoxia in prostate cancer prior to radical prostatectomy. Blood oxygen level dependent (BOLD, tissue oxygen level dependent (TOLD, dynamic contrast enhanced (DCE, and diffusion weighted imaging MRI were intercorrelated and compared with the Gleason score. The apparent diffusion coefficient (ADC was significantly lower in tumor than normal prostate. Baseline R2* (BOLD-contrast was significantly higher in tumor than normal prostate. Upon the oxygen breathing challenge, R2* decreased significantly in the tumor tissue, suggesting improved vascular oxygenation, however changes in R1 were minimal. R2* of contralateral normal prostate decreased in most cases upon oxygen challenge, although the differences were not significant. Moderate correlation was found between ADC and Gleason score. ADC and R2* were correlated and trends were found between Gleason score and R2*, as well as maximum-intensity-projection and area-under-the-curve calculated from DCE. Tumor ADC and R2* have been associated with tumor hypoxia, and thus the correlations are of particular interest. A multi-parametric approach including oxygen-enhanced MRI is feasible and promises further insights into the pathophysiological information of tumor microenvironment.

  1. Oxygenation measurement by multi-wavelength oxygen-dependent phosphorescence and delayed fluorescence: catchment depth and application in intact heart

    NARCIS (Netherlands)

    Balestra, Gianmarco M.; Aalders, Maurice C. G.; Specht, Patricia A. C.; Ince, Can; Mik, Egbert G.

    2015-01-01

    Oxygen delivery and metabolism represent key factors for organ function in health and disease. We describe the optical key characteristics of a technique to comprehensively measure oxygen tension (PO(2)) in myocardium, using oxygen-dependent quenching of phosphorescence and delayed fluorescence of

  2. Impact of partial pressure of oxygen in blood samples on the performance of systems for self-monitoring of blood glucose.

    Science.gov (United States)

    Schmid, Christina; Baumstark, Annette; Pleus, Stefan; Haug, Cornelia; Tesar, Martina; Freckmann, Guido

    2014-03-01

    The partial pressure of oxygen (pO2) in blood samples can affect glucose measurements with oxygen-sensitive systems. In this study, we assessed the influence of different pO2 levels on blood glucose (BG) measurements with five glucose oxidase (GOD) systems and one glucose dehydrogenase (GDH) system. All selected GOD systems were indicated by the manufacturers to be sensitive to increased oxygen content of the blood sample. Venous blood samples of 16 subjects (eight women, eight men; mean age, 52 years; three with type 1 diabetes, four with type 2 diabetes, and nine without diabetes) were collected. Aliquots of each sample were adjusted to the following pO2 values: ≤45 mm Hg, approximately 70 mm Hg, and ≥150 mm Hg. For each system, five consecutive measurements on each sample were performed using the same test strip lot. Relative differences between the mean BG value at a pO2 level of approximately 70 mm Hg, which was considered to be similar to pO2 values in capillary blood samples, and the mean BG value at pO2 levels ≤45 mm Hg and ≥150 mm Hg were calculated. The GOD systems showed mean relative differences between 11.8% and 44.5% at pO2 values ≤45 mm Hg and between -14.6% and -21.2% at pO2 values ≥150 mm Hg. For the GDH system, the mean relative differences were -0.3% and -0.2% at pO2 values ≤45 mm Hg and ≥150 mm Hg, respectively. The magnitude of the pO2 impact on BG measurements seems to vary among the tested oxygen-sensitive GOD systems. The pO2 range in which oxygen-sensitive systems operate well should be provided in the product information.

  3. TECHNIQUES OF EVALUATION OF HEMOGLOBIN OXYGEN SATURATION IN CLINICAL OPHTHALMOLOGY

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2016-01-01

    Full Text Available Oxygen content in body fluids and tissues is an important indicator of life support functions. A number of ocular pathologies, e.g. glaucoma, are of presumable vascular origin which means altered blood supply and oxygen circulation. Most oxygen is transported in the blood in the association with hemoglobin. When passing through the capillaries, hemoglobin releases oxygen, converting from oxygenated form to deoxygenated form. This process is accompanied by the changes in spectral characteristics of hemoglobin which result in different colors of arterial and venous blood. Photometric technique for the measurement of oxygen saturation in blood is based on the differences in light absorption by different forms of hemoglobin. The measurement of saturation is called oximetry. Pulse oximetry with assessment of tissue oxygenation is the most commonly used method in medicine. The degree of hemoglobin oxygen saturation in the eye blood vessels is the most accessible for noninvasive studies during ophthalmoscopy and informative. Numerous studies showed the importance of this parameter for the diagnosis of retinopathy of various genesis, metabolic status analysis in hyperglycemia, diagnosis and control of treatment of glaucoma and other diseases involving alterations in eye blood supply. The specific method for evaluation of oxygen concentration is the measurement of pressure of oxygen dissolved in the blood, i.e. partial pressure of oxygen. In ophthalmological practice, this parameter is measured in anterior chamber fluid evaluating oxygen level for several ophthalmopathies including different forms of glaucoma, for instillations of hypotensive eye drops as well as in vitreous body near to the optic disc under various levels of intraocular pressure. Currently, monitoring of oxygen saturation in retinal blood vessels, i.e. retinal oximetry, is well developed. This technique is based on the assessment of light absorption by blood depending on

  4. Local blood-brain barrier penetration following systemic contrast medium administration

    International Nuclear Information System (INIS)

    Utz, R.; Ekholm, S.E.; Isaac, L.; Sands, M.; Fonte, D.

    1988-01-01

    The present study was initiated by a severe complication in a patient with renal dysfunction who developed cortical blindness and weakness of her left extremities 30 hours following renal and abdominal angiography. To evaluate the impact of prolonged high serum concentrations of contrast medium (CM) this clinical situation was simulated in a laboratory model using sheep with elevated serum levels of contrast medium maintained for 48 hours. The experimental data did not support the theory that the prolonged exposure to high circulating levels of contrast medium (4 ml/kg body weight of meglumine diatrizoate 60%) is sufficient alone to cause penetration of the blood-brain barrier. (orig.)

  5. Implementation of laser speckle contrast analysis as connection kit for mobile phone for assessment of skin blood flow

    Science.gov (United States)

    Jakovels, Dainis; Saknite, Inga; Spigulis, Janis

    2014-05-01

    Laser speckle contrast analysis (LASCA) offers a non-contact, full-field, and real-time mapping of capillary blood flow and can be considered as an alternative method to Laser Doppler perfusion imaging. LASCA technique has been implemented in several commercial instruments. However, these systems are still too expensive and bulky to be widely available. Several optical techniques have found new implementations as connection kits for mobile phones thus offering low cost screening devices. In this work we demonstrate simple implementation of LASCA imaging technique as connection kit for mobile phone for primary low-cost assessment of skin blood flow. Stabilized 650 nm and 532 nm laser diode modules were used for LASCA illumination. Dual wavelength illumination could provide additional information about skin hemoglobin and oxygenation level. The proposed approach was tested for arterial occlusion and heat test. Besides, blood flow maps of injured and provoked skin were demonstrated.

  6. The effect of blood inflow and B(1)-field inhomogeneity on measurement of the arterial input function in axial 3D spoiled gradient echo dynamic contrast-enhanced MRI.

    Science.gov (United States)

    Roberts, Caleb; Little, Ross; Watson, Yvonne; Zhao, Sha; Buckley, David L; Parker, Geoff J M

    2011-01-01

    A major potential confound in axial 3D dynamic contrast-enhanced magnetic resonance imaging studies is the blood inflow effect; therefore, the choice of slice location for arterial input function measurement within the imaging volume must be considered carefully. The objective of this study was to use computer simulations, flow phantom, and in vivo studies to describe and understand the effect of blood inflow on the measurement of the arterial input function. All experiments were done at 1.5 T using a typical 3D dynamic contrast-enhanced magnetic resonance imaging sequence, and arterial input functions were extracted for each slice in the imaging volume. We simulated a set of arterial input functions based on the same imaging parameters and accounted for blood inflow and radiofrequency field inhomogeneities. Measured arterial input functions along the vessel length from both in vivo and the flow phantom agreed with simulated arterial input functions and show large overestimations in the arterial input function in the first 30 mm of the vessel, whereas arterial input functions measured more centrally achieve accurate contrast agent concentrations. Use of inflow-affected arterial input functions in tracer kinetic modeling shows potential errors of up to 80% in tissue microvascular parameters. These errors emphasize the importance of careful placement of the arterial input function definition location to avoid the effects of blood inflow. © 2010 Wiley-Liss, Inc.

  7. BLOOD SUBSTITUTES: EVOLUTION FROM NON-CARRYING TO OXYGEN AND GAS CARRYING FLUIDS

    Science.gov (United States)

    Cabrales, Pedro; Intaglietta, Marcos

    2013-01-01

    The development of oxygen (O2) carrying blood substitutes has evolved from the goal of replicating blood O2 transports properties to that of preserving microvascular and organ function, reducing the inherent or potential toxicity of the material used to carry O2, and treating pathologies initiated by anemia and hypoxia. Furthermore, the emphasis has shifted from blood replacement fluid to “O2 therapeutics” that restore tissue oxygenation to specific tissues regions. This review covers the different alternatives, potential and limitations of hemoglobin based O2 carriers (HBOCs) and perfluorocarbon based O2 carriers (PFCOCs), with emphasis on the physiological conditions disturbed in the situation that they will be used. It describes how concepts learned from plasma expanders without O2 carrying capacity can be applied to maintain O2 delivery and summarizes the microvascular responses due to HBOCs and PFCOCs. This review also presents alternative applications of HBOCs and PFCOCs namely: 1) How HBOC O2 affinity can be engineered to target O2 delivery to hypoxic tissues; and 2) How the high gas solubility of PFCOCs provides new opportunities for carrying, dissolving and delivering gases with biological activity. It is concluded that current blood substitutes development has amplified their applications horizon by devising therapeutic functions for oxygen carriers requiring limited O2 delivery capacity restoration. Conversely, full, blood-like O2 carrying capacity re-establishment awaits control of O2 carrier toxicity. PMID:23820271

  8. The Effects of Blood Glucose Levels on Cognitive Performance: A Review of the Literature

    Science.gov (United States)

    Feldman, Jolene; Barshi, Immanuel

    2007-01-01

    The purpose of this review paper is to discuss the research literature on the effects of blood glucose levels on executive and non-executive functions in humans. The review begins with a brief description of blood glucose, how it has been studied, previous syntheses of prior studies, and basic results regarding the role of blood glucose on cognitive functioning. The following sections describe work that investigated the effect of blood glucose on both non-executive and executive functions (e.g., sensory processing, psychomotor functioning, attention, vigilance, memory, language and communication, judgement and decision-making, and complex task performance). Within each section, summaries of the findings and challenges to the literature are included. Measurement conversions of blood glucose levels, blood glucose values, and associated symptoms are depicted. References to the types of tests used to investigate blood glucose and cognitive performance are provided. For more detailed descriptions of references within (and in addition to) this paper, an annotated bibliography is also provided. Several moderator variables including individual differences and contextual variables related to the effects of blood glucose levels on performance (e.g., age, gender, time of day, familiarity with the task and symptom awareness, expectancy effects, dose dependent effects, time dependent effects, task specific effects, rising and falling blood glucose levels, and speed and/or accuracy trade-offs) are addressed later in the paper. Some suggestions for future experimental methodologies are also made.

  9. Which side of the balance determines the frequency of vaso-occlusive crises in children with sickle cell anemia: Blood viscosity or microvascular dysfunction?

    Science.gov (United States)

    Charlot, Keyne; Romana, Marc; Moeckesch, Berenike; Jumet, Stéphane; Waltz, Xavier; Divialle-Doumdo, Lydia; Hardy-Dessources, Marie-Dominique; Petras, Marie; Tressières, Benoît; Tarer, Vanessa; Hue, Olivier; Etienne-Julan, Maryse; Antoine-Jonville, Sophie; Connes, Philippe

    2016-01-01

    Vascular resistance and tissue perfusion may be both affected by impaired vascular function and increased blood viscosity. Little is known about the effects of vascular function on the occurrence of painful vaso-occlusive crises (VOC) in children with sickle cell anemia (SCA). The aim of the present study was to determine which side of the balance (blood viscosity or vascular function) is the most deleterious in SCA and increases the risk for frequent hospitalized VOC. Microvascular function, microcirculatory oxygenation and blood viscosity were determined in a group of 22 SCA children/adolescents at steady state and a group of 13 healthy children/adolescents. Univariate analyses demonstrated blunted microvascular reactivity during local thermal heating test and decreased microcirculatory oxygenation in SCA children compared to controls. Multivariate analysis revealed that increased blood viscosity and decreased microcirculatory oxygenation were independent risk factors of frequent VOC in SCA. In contrast, the level of microvascular dysfunction does not predict VOC rate. In conclusion, increased blood viscosity is usually well supported in healthy individuals where vascular function is not impaired. However, in the context of SCA, microvascular function is impaired and any increase of blood viscosity or decrease in microcirculatory oxygenation would increase the risks for frequent VOC. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    Science.gov (United States)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

    2007-01-01

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO2) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO2) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO2 and HHb, total haemoglobin concentration and SO2. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l-1 (±58 µM) and ±4

  11. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    Energy Technology Data Exchange (ETDEWEB)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul [Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, London WC1E 6BT (United Kingdom)

    2007-01-07

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO{sub 2}) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO{sub 2}) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO{sub 2} and HHb, total haemoglobin concentration and SO{sub 2}. The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of {+-}3

  12. Quantitative spatially resolved measurement of tissue chromophore concentrations using photoacoustic spectroscopy: application to the measurement of blood oxygenation and haemoglobin concentration

    International Nuclear Information System (INIS)

    Laufer, Jan; Delpy, Dave; Elwell, Clare; Beard, Paul

    2007-01-01

    A new approach based on pulsed photoacoustic spectroscopy for non-invasively quantifying tissue chromophore concentrations with high spatial resolution has been developed. The technique is applicable to the quantification of tissue chromophores such as oxyhaemoglobin (HbO 2 ) and deoxyhaemoglobin (HHb) for the measurement of physiological parameters such as blood oxygen saturation (SO 2 ) and total haemoglobin concentration. It can also be used to quantify the local accumulation of targeted contrast agents used in photoacoustic molecular imaging. The technique employs a model-based inversion scheme to recover the chromophore concentrations from photoacoustic measurements. This comprises a numerical forward model of the detected time-dependent photoacoustic signal that incorporates a multiwavelength diffusion-based finite element light propagation model to describe the light transport and a time-domain acoustic model to describe the generation, propagation and detection of the photoacoustic wave. The forward model is then inverted by iteratively fitting it to measurements of photoacoustic signals acquired at different wavelengths to recover the chromophore concentrations. To validate this approach, photoacoustic signals were generated in a tissue phantom using nanosecond laser pulses between 740 nm and 1040 nm. The tissue phantom comprised a suspension of intralipid, blood and a near-infrared dye in which three tubes were immersed. Blood at physiological haemoglobin concentrations and oxygen saturation levels ranging from 2% to 100% was circulated through the tubes. The signal amplitude from different temporal sections of the detected photoacoustic waveforms was plotted as a function of wavelength and the forward model fitted to these data to recover the concentrations of HbO 2 and HHb, total haemoglobin concentration and SO 2 . The performance was found to compare favourably to that of a laboratory CO-oximeter with measurement resolutions of ±3.8 g l -1 (±58

  13. Blood oxygen saturation determined by transmission spectrophotometry of hemolyzed blood samples

    Science.gov (United States)

    Malik, W. M.

    1967-01-01

    Use of the Lambert-Beer Transmission Law determines blood oxygen saturation of hemolyzed blood samples. This simplified method is based on the difference in optical absorption properties of hemoglobin and oxyhemoglobin.

  14. The impact of including spatially longitudinal heterogeneities of vessel oxygen content and vascular fraction in 3D tumor oxygenation models on predicted radiation sensitivity.

    Science.gov (United States)

    Lagerlöf, Jakob H; Kindblom, Jon; Bernhardt, Peter

    2014-04-01

    Oxygen distribution models have been used to analyze the influences of oxygen tensions on tissue response after radiotherapy. These distributions are often generated assuming constant oxygen tension in the blood vessels. However, as red blood cells progress through the vessels, oxygen is continuously released into the plasma and the surrounding tissue, resulting in longitudinally varying oxygen levels in the blood vessels. In the present study, the authors investigated whether a tumor oxygenation model that incorporated longitudinally varying oxygen levels would provide different predictions of necrotic fractions and radiosensitivity compared to commonly used models with a constant oxygen pressure. Our models simulated oxygen diffusion based on a Green's function approach and oxygen consumption according to the Michaelis-Menten equation. The authors constructed tumor models with different vascular fractions (VFs), from which they generated depth oxygenation curves and a look-up table of oxygen pressure gradients. The authors evaluated models of spherical tumors of various sizes, from 1 to 10(4) mg. The authors compared the results from a model with constant vessel oxygen (CVO) pressure to those from models with longitudinal variations in oxygen saturation and either a constant VF (CVF) or variable VF (VVF) within the tumor tissue. The authors monitored the necrotic fractions, defined as tumor regions with an oxygen pressure below 1 mmHg. Tumor radiation sensitivity was expressed as D99, the homogeneous radiation dose required for a tumor control probability of 0.99. In the CVO saturation model, no necrosis was observed, and decreasing the VF could only decrease the D99 by up to 10%. Furthermore, the D99 vs VF dependence was similar for different tumor masses. Compared to the CVO model, the extended CVF and VVF models provided clearly different results, including pronounced effects of VF and tumor size on the necrotic fraction and D99, necrotic fractions ranging

  15. Functional and biocompatibility performances of an integrated Maglev pump-oxygenator.

    Science.gov (United States)

    Zhang, Tao; Cheng, Guangming; Koert, Andrew; Zhang, Juntao; Gellman, Barry; Yankey, G Kwame; Satpute, Aditee; Dasse, Kurt A; Gilbert, Richard J; Griffith, Bartley P; Wu, Zhongjun J

    2009-01-01

    To provide respiratory support for patients with lung failure, a novel compact integrated pump-oxygenator is being developed. The functional and biocompatibility performances of this device are presented. The pump-oxygenator is designed by combining a magnetically levitated pump/rotor with a uniquely configured hollow fiber membrane bundle to create an assembly free, ultracompact, all-in-one system. The hemodynamics, gas transfer and biocompatibility performances of this novel device were investigated both in vitro in a circulatory flow loop and in vivo in an ovine animal model. The in vitro results showed that the device was able to pump blood flow from 2 to 8 L/min against a wide range of pressures and to deliver an oxygen transfer rate more than 300 mL/min at a blood flow of 6 L/min. Blood damage tests demonstrated low hemolysis (normalized index of hemolysis [NIH] approximately 0.04) at a flow rate of 5 L/min against a 100-mm Hg afterload. The data from five animal experiments (4 h to 7 days) demonstrated that the device could bring the venous blood to near fully oxygen-saturated condition (98.6% +/- 1.3%). The highest oxygen transfer rate reached 386 mL/min. The gas transfer performance was stable over the study duration for three 7-day animals. There was no indication of blood damage. The plasma free hemoglobin and platelet count were within the normal ranges. No gross thrombus is found on the explanted pump components and fiber surfaces. Both in vitro and in vivo results demonstrated that the newly developed pump-oxygenator can achieve sufficient blood flow and oxygen transfer with excellent biocompatibility.

  16. Determination of relative CMRO2 from CBF and BOLD changes: significant increase of oxygen consumption rate during visual stimulation

    DEFF Research Database (Denmark)

    Kim, S.G.; Rostrup, Egill; Larsson, H.B.

    1999-01-01

    signal changes were measured simultaneously using the flow-sensitive alternating inversion recovery (FAIR) technique. During hypercapnia established by an end-tidal CO2 increase of 1.46 kPa, CBF in the visual cortex increased by 47.3 +/- 17.3% (mean +/- SD; n = 9), and deltaR2* was -0.478 +/- 0.147 sec......The blood oxygenation level-dependent (BOLD) effect in functional magnetic resonance imaging depends on at least partial uncoupling between cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) changes. By measuring CBF and BOLD simultaneously, the relative change in CMRO2 can...

  17. Retinal hemodynamic oxygen reactivity assessed by perfusion velocity, blood oximetry and vessel diameter measurements

    DEFF Research Database (Denmark)

    Klefter, Oliver Niels; Lauritsen, Anne Øberg; Larsen, Michael

    2015-01-01

    PURPOSE: To test the oxygen reactivity of a fundus photographic method of measuring macular perfusion velocity and to integrate macular perfusion velocities with measurements of retinal vessel diameters and blood oxygen saturation. METHODS: Sixteen eyes in 16 healthy volunteers were studied at two...... is a valid method for assessing macular perfusion. Results were consistent with previous observations of hyperoxic blood flow reduction using blue field entoptic and laser Doppler velocimetry. Retinal perfusion seemed to be regulated around individual set points according to blood glucose levels. Multimodal...

  18. Exploring brain function with magnetic resonance imaging

    International Nuclear Information System (INIS)

    Di Salle, F.; Formisano, E.; Linden, D.E.J.; Goebel, R.; Bonavita, S.; Pepino, A.; Smaltino, F.; Tedeschi, G.

    1999-01-01

    Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology

  19. Exploring brain function with magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Di Salle, F.; Formisano, E.; Linden, D.E.J.; Goebel, R.; Bonavita, S.; Pepino, A.; Smaltino, F.; Tedeschi, G

    1999-05-01

    Since its invention in the early 1990s, functional magnetic resonance imaging (fMRI) has rapidly assumed a leading role among the techniques used to localize brain activity. The spatial and temporal resolution provided by state-of-the-art MR technology and its non-invasive character, which allows multiple studies of the same subject, are some of the main advantages of fMRI over the other functional neuroimaging modalities that are based on changes in blood flow and cortical metabolism. This paper describes the basic principles and methodology of fMRI and some aspects of its application to functional activation studies. Attention is focused on the physiology of the blood oxygenation level-dependent (BOLD) contrast mechanism and on the acquisition of functional time-series with echo planar imaging (EPI). We also provide an introduction to the current strategies for the correction of signal artefacts and other image processing techniques. In order to convey an idea of the numerous applications of fMRI, we will review some of the recent results in the fields of cognitive and sensorimotor psychology and physiology.

  20. 21 CFR 868.1200 - Indwelling blood oxygen partial pressure (PO2) analyzer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Indwelling blood oxygen partial pressure (PO2... Indwelling blood oxygen partial pressure (PO2) analyzer. (a) Identification. An indwelling blood oxygen... electrode) and that is used to measure, in vivo, the partial pressure of oxygen in blood to aid in...

  1. MRI to assess renal structure and function.

    Science.gov (United States)

    Artunc, Ferruh; Rossi, Cristina; Boss, Andreas

    2011-11-01

    In addition to excellent anatomical depiction, MRI techniques have expanded to study functional aspects of renal physiology, such as renal perfusion, glomerular filtration rate (GFR) or tissue oxygenation. This review will focus on current developments with an emphasis on clinical applicability. The method of GFR determination is largely heterogeneous and still has weaknesses. However, the technique of employing liver disappearance curves has been shown to be accurate in healthy persons and patients with chronic kidney disease. In potential kidney donors, complete evaluation of kidney anatomy and function can be accomplished in a single-stop investigation. Techniques without contrast media can be utilized to measure renal tissue oxygenation (blood oxygen level-dependent MRI) or perfusion (arterial spin labeling) and could aid in the diagnosis and treatment of ischemic renal diseases, such as renal artery stenosis. Diffusion imaging techniques may provide information on spatially restricted water diffusion and tumor cellularity. Functional MRI opens new horizons in studying renal physiology and pathophysiology in vivo. Although extensively utilized in research, labor-intensive postprocessing and lack of standardization currently limit the clinical applicability of functional MRI. Further studies are necessary to evaluate the clinical value of functional magnetic resonance techniques for early discovery and characterization of kidney disease.

  2. Regional cerebral blood flow and oxygen consumption during normal human sleep

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Ken [Toho Univ., Tokyo (Japan). School of Medicine

    1989-09-01

    Regional cerebral blood flow (rCBF), regional oxygen extraction fraction (rCEF) and regional cerebral metabolic rate for oxygen (rCMRO{sub 2}) were measured using the continuous inhalation technique for {sup 15}O with positron emission tomography (PET) during both wakefulness and sleep. Ten paid volunteers, with a mean age of 21.6 yrs., were deprived of sleep for a period of approximately 20 hours, and the experiments were performed mostly in the morning. {sup 15}O activity of both whole blood and the plasma, pixel count of PET, total arterial blood oxygen content were used for analysis of rCBF, rOEF and rCMRO{sub 2}. PET scannings were carried out mostly during the very light non-rapid eye movement (NREM) sleep, i.e. stage 1 and/or 2, and wakefulness. About 10 minutes after the start of continuous inhalation of {sup 15}O gas, the {sup 15}O activity of the brain was found to be in a steady-state condition. During this steady-state condition, PET scannings were performed for about 10 minutes. Regions of interest, square in shape and having an area of 2.8 cm{sup 3}, were set in each cortex on PET images of a horizontal cross-section of the brain, set at 45 mm above the orbitomeatal line. The rCBF and rCMRO{sub 2} were analysed in 5 of 10 male subjects during both wakefulness and NREM sleep, and only 3 were done during three sleep stages, including REM sleep. Levels of rCBF and rCMRO{sub 2} were found to be decreased in NREM sleep, and the decreasing rates were calculated at 10.2% and 7.6% from the level of wakefulness, respectively. There was no significant difference in the mean value of rOEF between wakefulness and NREM sleep. There were no significant regional differences found in the rate of decrease among the frontal, temporal and occipital cortices. It was considered that the decrease of rCBF and rCMRO{sub 2} during NREM sleep suggested a decrease of the activity levels in the cerebral functions. (author).

  3. SREBP controls oxygen-dependent mobilization of retrotransposons in fission yeast.

    Directory of Open Access Journals (Sweden)

    Alfica Sehgal

    2007-08-01

    Full Text Available Retrotransposons are mobile genetic elements that proliferate through an RNA intermediate. Transposons do not encode transcription factors and thus rely on host factors for mRNA expression and survival. Despite information regarding conditions under which elements are upregulated, much remains to be learned about the regulatory mechanisms or factors controlling retrotransposon expression. Here, we report that low oxygen activates the fission yeast Tf2 family of retrotransposons. Sre1, the yeast ortholog of the mammalian membrane-bound transcription factor sterol regulatory element binding protein (SREBP, directly induces the expression and mobilization of Tf2 retrotransposons under low oxygen. Sre1 binds to DNA sequences in the Tf2 long terminal repeat that functions as an oxygen-dependent promoter. We find that Tf2 solo long terminal repeats throughout the genome direct oxygen-dependent expression of adjacent coding and noncoding sequences, providing a potential mechanism for the generation of oxygen-dependent gene expression.

  4. Dynamic Contrast-Enhanced Computed Tomography-Derived Blood Volume and Blood Flow Correlate With Patient Outcome in Metastatic Renal Cell Carcinoma

    DEFF Research Database (Denmark)

    Mains, Jill Rachel; Donskov, Frede; Pedersen, Erik Morre

    2017-01-01

    = 7). Using a prototype software program (Advanced Perfusion and Permeability Application, Philips Healthcare, Best, the Netherlands), blood volume (BV), blood flow (BF), and permeability surface area product (PS) were calculated for each tumor at baseline, week 5, and week 10. These parameters......OBJECTIVES: The aim was to explore the potential for using dynamic contrast-enhanced computed tomography as a noninvasive functional imaging biomarker before and during the early treatment of metastatic renal cell carcinoma (mRCC). MATERIALS AND METHODS: Dynamic contrast-enhanced computed...

  5. Mitochondrial modulation of oxygen-dependent radiosensitivity in some human tumour cell lines.

    LENUS (Irish Health Repository)

    Anoopkumar-Dukie, S

    2009-10-01

    Oxygen-dependent radiosensitivity of tumour cells reflects direct oxidative damage to DNA, but non-nuclear mechanisms including signalling pathways may also contribute. Mitochondria are likely candidates because not only do they integrate signals from each of the main kinase pathways but mitochondrial kinases responsive to oxidative stress communicate to the rest of the cell. Using pharmacological and immunochemical methods, we tested the role of mitochondrial permeability transition (MPT) and the Bcl-2 proteins in oxygen-dependent radiosensitivity. Drug-treated or untreated cervical cancer HeLa, breast cancer MCF-7 and melanoma MeWo cell lines were irradiated at 6.2 Gy under normoxic and hypoxic conditions then allowed to proliferate for 7 days. The MPT blocker cyclosporin A (2 microM) strongly protected HeLa but not the other two lines against oxygen-dependent radiosensitivity. By contrast, bongkrekic acid (50 microM), which blocks MPT by targeting the adenine nucleotide transporter, had only marginal effect and calcineurin inhibitor FK-506 (0.1 microM) had none. Nor was evidence found for the modulation of oxygen-dependent radiosensitivity by Bax\\/Bcl-2 signalling, mitochondrial ATP-dependent potassium (mitoK(ATP)) channels or mitochondrial Ca(2+) uptake. In conclusion, calcineurin-independent protection by cyclosporin A suggests that MPT but not mitoK(ATP) or the mitochondrial apoptosis pathway plays a causal role in oxygen-dependent radiosensitivity of HeLa cells. Targeting MPT may therefore improve the effectiveness of radiotherapy in some solid tumours.

  6. Structural architecture supports functional organization in the human aging brain at a regionwise and network level.

    Science.gov (United States)

    Zimmermann, Joelle; Ritter, Petra; Shen, Kelly; Rothmeier, Simon; Schirner, Michael; McIntosh, Anthony R

    2016-07-01

    Functional interactions in the brain are constrained by the underlying anatomical architecture, and structural and functional networks share network features such as modularity. Accordingly, age-related changes of structural connectivity (SC) may be paralleled by changes in functional connectivity (FC). We provide a detailed qualitative and quantitative characterization of the SC-FC coupling in human aging as inferred from resting-state blood oxygen-level dependent functional magnetic resonance imaging and diffusion-weighted imaging in a sample of 47 adults with an age range of 18-82. We revealed that SC and FC decrease with age across most parts of the brain and there is a distinct age-dependency of regionwise SC-FC coupling and network-level SC-FC relations. A specific pattern of SC-FC coupling predicts age more reliably than does regionwise SC or FC alone (r = 0.73, 95% CI = [0.7093, 0.8522]). Hence, our data propose that regionwise SC-FC coupling can be used to characterize brain changes in aging. Hum Brain Mapp 37:2645-2661, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. Red blood cell transfusions and tissue oxygenation in anemic hematology outpatients

    NARCIS (Netherlands)

    Yuruk, Koray; Bartels, Sebastiaan A.; Milstein, Dan M. J.; Bezemer, Rick; Biemond, Bart J.; Ince, Can

    2012-01-01

    BACKGROUND: There is little clinical evidence that red blood cell (RBC) transfusions improve oxygen availability at the microcirculatory level. We tested the hypotheses that anemia in chronically anemic patients with relatively healthy microcirculation would be associated with low tissue hemoglobin

  8. Improved arterial blood oxygenation following intravenous infusion of cold supersaturated dissolved oxygen solution.

    Science.gov (United States)

    Grady, Daniel J; Gentile, Michael A; Riggs, John H; Cheifetz, Ira M

    2014-01-01

    One of the primary goals of critical care medicine is to support adequate gas exchange without iatrogenic sequelae. An emerging method of delivering supplemental oxygen is intravenously rather than via the traditional inhalation route. The objective of this study was to evaluate the gas-exchange effects of infusing cold intravenous (IV) fluids containing very high partial pressures of dissolved oxygen (>760 mm Hg) in a porcine model. Juvenile swines were anesthetized and mechanically ventilated. Each animal received an infusion of cold (13 °C) Ringer's lactate solution (30 mL/kg/hour), which had been supersaturated with dissolved oxygen gas (39.7 mg/L dissolved oxygen, 992 mm Hg, 30.5 mL/L). Arterial blood gases and physiologic measurements were repeated at 15-minute intervals during a 60-minute IV infusion of the supersaturated dissolved oxygen solution. Each animal served as its own control. Five swines (12.9 ± 0.9 kg) were studied. Following the 60-minute infusion, there were significant increases in PaO2 and SaO2 (P < 0.05) and a significant decrease in PaCO2 (P < 0.05), with a corresponding normalization in arterial blood pH. Additionally, there was a significant decrease in core body temperature (P < 0.05) when compared to the baseline preinfusion state. A cold, supersaturated dissolved oxygen solution may be intravenously administered to improve arterial blood oxygenation and ventilation parameters and induce a mild therapeutic hypothermia in a porcine model.

  9. In vivo imaging of brain ischemia using an oxygen-dependent degradative fusion protein probe.

    Directory of Open Access Journals (Sweden)

    Youshi Fujita

    Full Text Available Within the ischemic penumbra, blood flow is sufficiently reduced that it results in hypoxia severe enough to arrest physiological function. Nevertheless, it has been shown that cells present within this region can be rescued and resuscitated by restoring perfusion and through other protective therapies. Thus, the early detection of the ischemic penumbra can be exploited to improve outcomes after focal ischemia. Hypoxia-inducible factor (HIF-1 is a transcription factor induced by a reduction in molecular oxygen levels. Although the role of HIF-1 in the ischemic penumbra remains unknown, there is a strong correlation between areas with HIF-1 activity and the ischemic penumbra. We recently developed a near-infrared fluorescently labeled-fusion protein, POH-N, with an oxygen-dependent degradation property identical to the alpha subunit of HIF-1. Here, we conduct in vivo imaging of HIF-active regions using POH-N in ischemic brains after transient focal cerebral ischemia induced using the intraluminal middle cerebral artery occlusion technique in mice. The results demonstrate that POH-N enables the in vivo monitoring and ex vivo detection of HIF-1-active regions after ischemic brain injury and suggest its potential in imaging and drug delivery to HIF-1-active areas in ischemic brains.

  10. Cerebral tissue oxygen saturation and extraction in preterm infants before and after blood transfusion

    NARCIS (Netherlands)

    van Hoften, Jacorina C. R.; Verhagen, Elise A.; Keating, Paul; ter Horst, Hendrik J.; Bos, Arend F.

    Objective Preterm infants often need red blood cell (RBC) transfusions. The aim of this study was to determine whether haemoglobin levels before transfusion were associated with regional cerebral tissue oxygen saturation (r(c)SO(2)) and fractional tissue oxygen extraction (FTOE) and whether RBC

  11. The temperature dependence of intermediate range oxygen-oxygen correlations in liquid water

    International Nuclear Information System (INIS)

    Schlesinger, Daniel; Pettersson, Lars G. M.; Wikfeldt, K. Thor; Skinner, Lawrie B.; Benmore, Chris J.; Nilsson, Anders

    2016-01-01

    We analyze the recent temperature dependent oxygen-oxygen pair-distribution functions from experimental high-precision x-ray diffraction data of bulk water by Skinner et al. [J. Chem. Phys. 141, 214507 (2014)] with particular focus on the intermediate range where small, but significant, correlations are found out to 17 Å. The second peak in the pair-distribution function at 4.5 Å is connected to tetrahedral coordination and was shown by Skinner et al. to change behavior with temperature below the temperature of minimum isothermal compressibility. Here we show that this is associated also with a peak growing at 11 Å which strongly indicates a collective character of fluctuations leading to the enhanced compressibility at lower temperatures. We note that the peak at ∼13.2 Å exhibits a temperature dependence similar to that of the density with a maximum close to 277 K or 4 °C. We analyze simulations of the TIP4P/2005 water model in the same manner and find excellent agreement between simulations and experiment albeit with a temperature shift of ∼20 K.

  12. The temperature dependence of intermediate range oxygen-oxygen correlations in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, Daniel; Pettersson, Lars G. M., E-mail: Lars.Pettersson@fysik.su.se [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Wikfeldt, K. Thor [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Science Institute, University of Iceland, VR-III, 107 Reykjavik (Iceland); Skinner, Lawrie B.; Benmore, Chris J. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Nilsson, Anders [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2016-08-28

    We analyze the recent temperature dependent oxygen-oxygen pair-distribution functions from experimental high-precision x-ray diffraction data of bulk water by Skinner et al. [J. Chem. Phys. 141, 214507 (2014)] with particular focus on the intermediate range where small, but significant, correlations are found out to 17 Å. The second peak in the pair-distribution function at 4.5 Å is connected to tetrahedral coordination and was shown by Skinner et al. to change behavior with temperature below the temperature of minimum isothermal compressibility. Here we show that this is associated also with a peak growing at 11 Å which strongly indicates a collective character of fluctuations leading to the enhanced compressibility at lower temperatures. We note that the peak at ∼13.2 Å exhibits a temperature dependence similar to that of the density with a maximum close to 277 K or 4 °C. We analyze simulations of the TIP4P/2005 water model in the same manner and find excellent agreement between simulations and experiment albeit with a temperature shift of ∼20 K.

  13. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Jensen, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G

    Concentration of MRI contrast agents (CA) is commonly determined indirectly using their relaxation effect. In quantitative perfusion studies, the change in the relaxation following a bolus passage is converted into concentrations assuming identical relaxivities for tissue and blood. Simulations...

  14. Effects of blood transfusion on oxygen extraction ratio and central venous saturation in children after cardiac surgery.

    Science.gov (United States)

    Nasser, Bana; Tageldein, Mohmad; AlMesned, Abdulrahman; Kabbani, Mohammad

    2017-01-01

    Red blood cell transfusion is common in critically ill children after cardiac surgery. Since the threshold for hemoglobin (Hb) transfusion need is not well defined, the threshold Hb level at which dependent critical oxygen uptake-to-delivery (VO2-DO2) status compensation is uncertain. To assess the effects of blood transfusion on the oxygen extraction ratio (O2ER) and central venous oxygen saturation (ScvO2) to identify a critical O2ER value that could help us determine the critical need for blood transfusion. Prospective, observational cohort study. Cardiac Surgical Intensive Care Unit at Prince Sultan Cardiac Center in Qassim, Saudi Arabia. Between January 2013 and December 2015, we included all children with cardiac disease who underwent surgery and needed a blood transfusion. Demographic and laboratory data with physiological parameters before and 1 and 6 hours after transfusion were recorded and O2ER before and 6 hours after transfusion was computed. Cases were divided into two groups based on O2ER: Patients with increased O2ER (O2ER > 40%) and normal patients without increased O2ER (O2ER transfusion. Changes in O2ER and ScvO2 following blood transfusion. Of 103 patients who had blood transfusion, 75 cases had normal O2ER before transfusion while 28 cases had increased O2ER before transfusion. Following blood transfusion, O2ER and ScvO2 improved in the group that had increased O2ER before transfusion, but not in the group that had normal O2ER before transfusion. The clinical and hemodynamic indicators O2ER and ScvO2 may be considered as markers that can indicate a need for blood transfusion. The limitation of this study is the small number of patients that had increased O2ER before transfusion. There were few available variables to assess oxygen consumption.

  15. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats

    Science.gov (United States)

    Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential me...

  16. A numerical two layer model for blood oxygenation in lungs

    International Nuclear Information System (INIS)

    Aminatai, A.

    2001-01-01

    In the modelling of the simultaneous transport of O 2 and CO 2 in the pulmonary circulation described in our earlier studies, the blood has been treated as a homogeneous layer of haemoglobin solution. Since the size of the erythrocyte is not negligible in comparison with that of the capillary, the blood can no longer be considered as a homogeneous fluid and hence, It is worthwhile to consider the blood flow as a two-phase flow consisting of cells and plasma. In the present study, the heterogeneous nature of blood has been proposed by considering the axial train model for the flow [whitmore (1967)], in order to analyze the effect of cell free plasma layer on the process of blood oxygenation in pulmonary capillaries. The proposed model consists of a core of suspended erythrocytes surrounded by a cell free plasma layer near the wall. The coupled system of convective diffusion equaions together with the physiologically relevant boundary, entrance and interface conditions is solved numerically by a four-point semi-implicit scheme to gether with a fixed point iterative technique. The distance traversed by the blood before getting fully oxygenated is computed. It is shown that the core haematocrit and the thickness of the cell depleted layer affect the oxygenation process significantly. It is found that (i) oxygen takes longest and carbondioxide is the fastest to attain equilibraton, (ii) the blood is completely oxygenated within one-fifth part of its transit and (iii) the rate of oxygenation is smaller in case of homogeneous model than that in heterogenous model in the capillary. Finally, the effect of various physiological parameters on the rate of oxygenation has been examined

  17. Oxygen-dependent radiosensitivity of Escherichia coli and mitigation in lethality by superoxide dismutase

    International Nuclear Information System (INIS)

    Niwa, Taeko; Yamaguchi, Hikoyuki; Yano, Keiji

    1978-01-01

    Oxygen-dependent radiosensitivity of Escherichia coli W3623 his - was confirmed. Regarding cellular superoxide dismutase (SOD), cells grown oxically gained higher activity than those anoxically, however, the reinforced enzyme level could not compensate the oxygen effect, i.e., the enhanced lethal effect of oxic γ-irradiation. Rather, the enhancement of oxygen effect was found in cells grown oxically compared with those anoxically. Oxygen enhanced lethality was mitigated to the extent by the amount of added SOD into the cell suspension to be irradiated. The results supported a proposal that superoxide anion, O 2 - , is involved in the oxygen effect, with the most likely site of the damage in the outer structure of cell but not in the cell matrix. Reverse oxygen effect could be found with lambda phage DNA in transfecting ability. Added SOD protected phage DNA somewhat in oxic irradiation. While considerable protections were found in anoxic one with the added SOD even autoclaved but their function was still unknown. (auth.)

  18. Assessing renal function with a rapid, handy, point-of-care whole blood creatinine meter before using contrast materials

    International Nuclear Information System (INIS)

    Morita, Satoru; Suzuki, Kazufumi; Masukawa, Ai; Ueno, Eiko

    2011-01-01

    The aim of this prospective study was to assess the reliability of a rapid, handy, point-of-care whole blood creatinine meter (PCM) in patients who were scheduled to undergo contrast-enhanced computed tomography (CT) or magnetic resonance imaging (MRI). Among patients scheduled to undergo contrast-enhanced CT or MRI examinations, 113 patients who did not have creatinine data from the prescribed intervals before the examination day (in principle, 90 days for scheduled outpatients and 7 days for inpatients and urgent patients) were included. The estimated glomerular filtration rate (eGFR) was calculated using the creatinine values measured with the PCM and those from central laboratory measurements (LAB). The two eGFR values were compared statistically with the paired t-test, Pearson's correlation coefficient, and the Bland-Altman analysis. The mean eGFR measured with the PCM was slightly higher than the LAB value (81.2±24.6 vs. 70.2±19.7 ml/min/1.73 m 2 , P 2 ; limits of agreement were -22.4 to +44.4 ml/min/1.73 m 2 ) showed a moderate agreement with some degree of dispersion. The PCM can rapidly assess renal function using a small amount of blood almost equally to that of determined in the laboratory, which may help reduce the risk of contrast material-induced complications. (author)

  19. Effect of luminance contrast on BOLD-fMRI response in deaf and normal occipital visual cortex

    International Nuclear Information System (INIS)

    Xue Yanping; Zhai Renyou; Jiang Tao; Cui Yong; Zhou Tiangang; Rao Hengyi; Zhuo Yan

    2002-01-01

    Objective: To examine the effect of luminance contrast stimulus by using blood oxygenation level dependent functional magnetic resonance imaging (BOLD-fMRI) within deaf occipital visual cortex, and to compare the distribution, extent, and intensity of activated areas between deaf subjects and normal hearing subjects. Methods: Twelve deaf subjects (average age 16.5) and 15 normal hearing subjects (average age 23.7) were stimulated by 4 kinds of luminance contrast (0.7, 2.2, 50.0, 180.0 lm). The fMRI data were collected on GE 1.5 T Signa Horizon LX MRI system and analyzed by AFNI to generate the activation map. Results: Responding to all 4 kinds of stimulus luminance contrast, all deaf and normal subjects showed significant activations in occipital visual cortex. For both deaf and normal subjects, the number of activated pixels increased significantly with increasing luminance contrast (F normal = 4.27, P deaf = 6.41, P 0.05). The local mean activation level for all activated pixels remained constant with increasing luminance contrast. However, there was an increase in the mean activation level for those activated pixels common to all trials as the stimulus luminance contrast was increased, but no significant difference was found within them (F normal = 0.79, P > 0.05; F deaf = 1.6, P > 0.05). Conclusion: The effect of luminance contrast on occipital visual cortex of deaf is similar to but somewhat higher than that of normal hearing subjects. In addition, it also proved that fMRI is a feasible method in the study of the deaf visual cortex

  20. Oxygen as a factor in eukaryote evolution - Some effects of low levels of oxygen on Saccharomyces cerevisiae

    Science.gov (United States)

    Jahnke, L.; Klein, H. P.

    1979-01-01

    A comparative study of the effects of varying levels of oxygen on some of the metabolic functions of the primitive eukaryote, Saccharomyces cerevisiae, has shown that these cells are responsive to very low levels of oxygen: the level of palmitoyl-Co A desaturase was greatly enhanced by only 0.03 vol % oxygen. Similarly, an acetyl-CoA synthetase associated predominantly with anaerobic growth was stimulated by as little as 0.1% oxygen, while an isoenzyme correlated with aerobic growth was maximally active at much higher oxygen levels (greater than 1%). Closely following this latter pattern were three mitochondrial enzymes that attained maximal activity only under atmospheric levels of oxygen.

  1. Orientation-Dependent Oxygen Evolution on RuO2 without Lattice Exchange

    DEFF Research Database (Denmark)

    Stoerzinger, Kelsey A.; Diaz-Morales, Oscar; Kolb, Manuel

    2017-01-01

    the potential involvement of lattice oxygen in the OER mechanism with online electrochemical mass spectrometry, which showed no evidence of oxygen exchange on these oriented facets in acidic or basic electrolytes. Similar results were obtained for polyoriented RuO2 films and particles, in contrast to previous...... work, suggesting lattice oxygen is not exchanged in catalyzing OER on crystalline RuO2 surfaces. This hypothesis is supported by the correlation of activity with the number of active Ru-sites calculated by density functional theory, where more active facets bind oxygen more weakly. This new...

  2. Surface core level shifts of clean and oxygen covered Ir(111)

    Energy Technology Data Exchange (ETDEWEB)

    Bianchi, M; Cassese, D; Cavallin, A; Comin, R; Orlando, F; Postregna, L [Universita degli Studi di Trieste, Via A Valerio 2, 34127, Trieste (Italy); Golfetto, E; Baraldi, A [Dipartimento di Fisica e CENMAT, Universita degli Studi di Trieste, Via A Valerio 2, 34127, Trieste (Italy); Lizzit, S [Sincrotrone Trieste S.C.p.A., S.S. 14 Km 163.5, 34012 Trieste (Italy)], E-mail: alessandro.baraldi@elettra.trieste.it

    2009-06-15

    We present the results of high resolution core level photoelectron spectroscopy employed to investigate the electronic structure of clean and oxygen covered Ir(111) surface. Ir 4f{sub 7/2} core level spectra are shown to be very sensitive to the local atomic environment. For the clean surface we detected two distinct components shifted by 550 meV, originated by surface and bulk atoms. The larger Gaussian width of the bulk component is explained as due to experimentally unresolved subsurface components. In order to determine the relevance of the phonon contribution we examined the thermal behaviour of the core level lineshape using the Hedin-Rosengren theory. From the phonon-induced spectral broadening we found the Debye temperature of bulk and surface atoms to be 298 and 181 K, respectively, which confirms the softening of the vibrational modes at the surface. Oxygen adsorption leads to the appearance of new surface core level components at -200 meV and +230 meV, which are interpreted as due to first-layer Ir atoms differently coordinated with oxygen. The coverage dependence of these components demonstrates that the oxygen saturation corresponds to 0.38 ML, in good agreement with recent density functional theory calculations.

  3. Effects of acetazolamide on cerebral blood flow and brain tissue oxygenation

    DEFF Research Database (Denmark)

    Lassen, N A; Friberg, L; Kastrup, J

    1987-01-01

    Oral administration of 1 g of acetazolamide to 8 normal subjects studied at sea level and in normoxia caused an acute increase in cerebral blood flow (CBF). During the subsequent prolonged oral treatment with 1 g of acetazolamide daily, CBF returned to normal within 2 days. The alveolar CO2 tension...... decreased gradually to 70% of the control value, indicating hyperventilation. At sea level hyperventilation will not increase brain oxygenation significantly in normal man, as the arterial oxygen content only increases minimally, while CBF is unchanged. At high altitude the beneficial effects...... of acetazolamide on the symptoms of acute mountain sickness may well be due to an improved oxygen supply to the brain, as hyperventilation will, at the low ambient PO2, cause a significant increase of the arterial oxygen content, while CBF presumably is unaffected by the drug. During hypoxia at high altitude...

  4. Relaxivity of blood pool contrast agent depends on the host tissue as suggested by semianalytical simulations

    DEFF Research Database (Denmark)

    Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij

    Concentration of magnetic resonance imaging (MRI) contrast agents (CA) cannot be measured directly and is commonly determined indirectly using their relaxation effect. This requires knowledge of the relaxivity of the used CA. Quantitative perfusion studies involve measurement of CA concentration...... studies (3,4) as demonstrated in (5). It was previously found (6) that the perfusion measurements using dynamic susceptibility contrast inherently overestimate cerebral blood flow and volume. In view of the present result, this is attributed to the significant difference in the relaxivity of the CA...

  5. Hyperpolarized 129Xe as an NMR probe for functional studies

    International Nuclear Information System (INIS)

    Wolber, J.

    2000-01-01

    The nuclear spin polarization of 129 Xe can be enhanced by several orders of magnitude using optical pumping techniques, resulting in a dramatic enhancement of the 129 Xe Nuclear Magnetic Resonance (NMR) signal. The 'hyperpolarized' gas can be used for Magnetic Resonance Imaging (MRI) of the void spaces of the lungs after introduction of the gas into the respiratory system. Furthermore, the high solubility of xenon in blood and lipids suggests the use of 129 Xe NMR for studying blood flow, permeability, perfusion and blood volume. Hyperpolarized 129 Xe MRI has the potential of combining the high sensitivity and functional information of radioactive tracer studies with the high spatial and temporal resolution of MRI. The spin-lattice relaxation time T 1 of 129 Xe in blood determines the loss of polarization during transit from the lungs to the tissue of interest. A difference in the relaxation times of xenon in oxygenated and deoxygenated blood could be used as a contrast mechanism in functional Magnetic Resonance Imaging (fMRI). In this thesis, the hyperpolarized 129 Xe T 1 in human blood is measured in vitro as a function of blood oxygenation, and the relevant relaxation mechanisms are discussed. A new and unexpected finding is that the hyperpolarized 129 Xe NMR spectrum in blood is highly sensitive to blood oxygenation. Therefore, hyperpolarized 129 Xe NMR provides a powerful means of measuring blood oxygenation quantitatively and non-invasively. The interaction of xenon with hemoglobin is responsible for an oxygen-dependent shift of the 129 Xe NMR resonance of xenon in red blood cells. Injection delivery of hyperpolarized 129 Xe in solution could be a more efficient method of administrating the gas for functional NMR studies. For this purpose, suitable biocompatible carrier media have been studied. In particular, the use of perfluorocarbon emulsions, which are already in use as blood substitutes, as delivery media for hyperpolarized 129 Xe has been investigates

  6. Blood glucose level reconstruction as a function of transcapillary glucose transport.

    Science.gov (United States)

    Koutny, Tomas

    2014-10-01

    A diabetic patient occasionally undergoes a detailed monitoring of their glucose levels. Over the course of a few days, a monitoring system provides a detailed track of their interstitial fluid glucose levels measured in their subcutaneous tissue. A discrepancy in the blood and interstitial fluid glucose levels is unimportant because the blood glucose levels are not measured continuously. Approximately five blood glucose level samples are taken per day, and the interstitial fluid glucose level is usually measured every 5min. An increased frequency of blood glucose level sampling would cause discomfort for the patient; thus, there is a need for methods to estimate blood glucose levels from the glucose levels measured in subcutaneous tissue. The Steil-Rebrin model is widely used to describe the relationship between blood and interstitial fluid glucose dynamics. However, we measured glucose level patterns for which the Steil-Rebrin model does not hold. Therefore, we based our research on a different model that relates present blood and interstitial fluid glucose levels to future interstitial fluid glucose levels. Using this model, we derived an improved model for calculating blood glucose levels. In the experiments conducted, this model outperformed the Steil-Rebrin model while introducing no additional requirements for glucose sample collection. In subcutaneous tissue, 26.71% of the calculated blood glucose levels had absolute values of relative differences from smoothed measured blood glucose levels less than or equal to 5% using the Steil-Rebrin model. However, the same difference interval was encountered in 63.01% of the calculated blood glucose levels using the proposed model. In addition, 79.45% of the levels calculated with the Steil-Rebrin model compared with 95.21% of the levels calculated with the proposed model had 20% difference intervals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Growth of jaguar cichlid (Cichlasoma managuense juveniles at different oxygen levels

    Directory of Open Access Journals (Sweden)

    Marco Acosta Nassar

    2016-03-01

    Full Text Available The dependence of growth on the disolved oxygen level was analyzed in juveniles of the guapote tigre, Cichlasoma managuense, in a recirculated system. The guapote tigre is relatively tolerant to low oxygen levels, averaging only a 17% reduction in growth rate per ppm oxygen in the range between 2 and 5 ppm.

  8. The effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients.

    Science.gov (United States)

    Yousefi, Hojatollah; Naderi, Mojgan; Daryabeigi, Reza

    2015-01-01

    Stressors in the intensive care unit (ICU) impair patients' comfort, excite the stress response, and increase oxygen consumption in their body. Non-medical interventions are recommended by several studies as a treatment to improve comfort in the ICU patients. Sensory stimulation is one of the most important interventions. Since arterial blood oxygen saturation is an important index of patients' clinical and respiratory condition, this study aimed to investigate the effect of sensory stimulation provided by family on arterial blood oxygen saturation in critical care patients. This study is a clinical trial conducted on 64 patients hospitalized in the ICU wards of Al-Zahra and Kashani hospitals in Isfahan, Iran in 2012 and 2013. The patients were selected by simple sampling method and were randomly assigned to two groups (study and control). Patients' arterial blood oxygen saturations were measured 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group, and simultaneously in the control group without any intervention. Repeated measures analysis of variance (ANOVA) showed a significant difference in the mean of arterial blood oxygen saturation levels 10 min before, immediately after, 10 min and 30 min after sensory stimulation in the study group (P 0.18). Application of sensory stimulations as a nursing and non-medical intervention by the family members improves comfort and increases the level of blood oxygen saturation in critical care patients.

  9. NEUROFEEDBACK USING FUNCTIONAL SPECTROSCOPY

    OpenAIRE

    Hinds, Oliver; Wighton, Paul; Tisdall, M. Dylan; Hess, Aaron; Breiter, Hans; van der Kouwe, André

    2014-01-01

    Neurofeedback based on real-time measurement of the blood oxygenation level-dependent (BOLD) signal has potential for treatment of neurological disorders and behavioral enhancement. Commonly employed methods are based on functional magnetic resonance imaging (fMRI) sequences that sacrifice speed and accuracy for whole-brain coverage, which is unnecessary in most applications. We present multi-voxel functional spectroscopy (MVFS): a system for computing the BOLD signal from multiple volumes of...

  10. Brain oxygen saturation assessment in neonates using T2-prepared blood imaging of oxygen saturation and near-infrared spectroscopy

    DEFF Research Database (Denmark)

    Alderliesten, Thomas; De Vis, Jill B; Lemmers, Petra Ma

    2017-01-01

    saturation in the sagittal sinus (R(2 )= 0.49, p = 0.023), but no significant correlations could be demonstrated with frontal and whole brain cerebral blood flow. These results suggest that measuring oxygen saturation by T2-prepared blood imaging of oxygen saturation is feasible, even in neonates. Strong...... sinus. A strong linear relation was found between the oxygen saturation measured by magnetic resonance imaging and the oxygen saturation measured by near-infrared spectroscopy (R(2 )= 0.64, p ..., and magnetic resonance imaging measures of frontal cerebral blood flow, whole brain cerebral blood flow and venous oxygen saturation in the sagittal sinus (R(2 )= 0.71, 0.50, 0.65; p 

  11. Breakdown of long-range temporal dependence in default mode and attention networks during deep sleep.

    Science.gov (United States)

    Tagliazucchi, Enzo; von Wegner, Frederic; Morzelewski, Astrid; Brodbeck, Verena; Jahnke, Kolja; Laufs, Helmut

    2013-09-17

    The integration of segregated brain functional modules is a prerequisite for conscious awareness during wakeful rest. Here, we test the hypothesis that temporal integration, measured as long-term memory in the history of neural activity, is another important quality underlying conscious awareness. For this aim, we study the temporal memory of blood oxygen level-dependent signals across the human nonrapid eye movement sleep cycle. Results reveal that this property gradually decreases from wakefulness to deep nonrapid eye movement sleep and that such decreases affect areas identified with default mode and attention networks. Although blood oxygen level-dependent spontaneous fluctuations exhibit nontrivial spatial organization, even during deep sleep, they also display a decreased temporal complexity in specific brain regions. Conversely, this result suggests that long-range temporal dependence might be an attribute of the spontaneous conscious mentation performed during wakeful rest.

  12. Blood creatinine level in postmortem cases.

    Science.gov (United States)

    Nishida, Atsushi; Funaki, Hironao; Kobayashi, Masaki; Tanaka, Yuka; Akasaka, Yoshihisa; Kubo, Toshikazu; Ikegaya, Hiroshi

    2015-05-01

    Blood chemical analysis for the diagnosis of diseases in forensic cases should be conducted in the same way as for clinical cases. However, it is sometimes difficult to obtain serum samples in forensic cases because of postmortem changes such as hemolysis and putrefaction. This study aimed to evaluate renal function in postmortem cases by blood creatinine analysis. The blood creatinine level was measured by high performance liquid chromatography (HPLC) using whole blood samples taken from 77 postmortem cases, and the relationships between blood creatinine level, postmortem interval, and cause of death were examined. The median blood creatinine level was found to be 1.15 mg/dL, with no significant differences between blood samples taken from different parts of the body. The blood creatinine level was stable for 3 days after death and gradually increased after that period, in line with a previous study using enzymatic analysis that found the serum creatinine level was stable in the early postmortem period. The blood creatinine level was high in the cases of blunt injury, intoxication, and in deaths caused by fire. This was considered to reflect acute renal dysfunction. However, the postmortem blood creatinine level remained higher than the clinical normal value despite omitting cases with renal dysfunction from the analysis. Therefore, we next investigated the change in postmortem creatinine levels in mice and found that the blood creatinine level increased with the emergence of rigor mortis. Our findings indicate that HPLC is useful in the postmortem evaluation of renal function even in the cases where serum cannot be obtained. However, the presence of rigor mortis should be considered in the evaluation of blood creatinine values. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

  13. Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, Sjannie, E-mail: sjannie.lefevre@biology.au.dk [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark); Jensen, Frank B. [Department of Biology, University of Southern Denmark, Odense (Denmark); Huong, Do.T.T. [College of Aquaculture and Fisheries, Can Tho University, Can Tho City (Viet Nam); Wang, Tobias [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark); Phuong, Nguyen T. [College of Aquaculture and Fisheries, Can Tho University, Can Tho City (Viet Nam); Bayley, Mark [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark)

    2011-07-15

    In this study we investigated nitrite (NO{sub 2}{sup -}) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO{sub 2max}) and critical swimming speed (U{sub crit}) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC{sub 50} of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO{sub 2max} and U{sub crit}. The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO{sub 2max} and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

  14. Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus.

    Science.gov (United States)

    Lefevre, Sjannie; Jensen, Frank B; Huong, Do T T; Wang, Tobias; Phuong, Nguyen T; Bayley, Mark

    2011-07-01

    In this study we investigated nitrite (NO₂⁻) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO(2max)) and critical swimming speed (U(crit)) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC₅₀ of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO(2max) and U(crit). The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO(2max) and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus

    International Nuclear Information System (INIS)

    Lefevre, Sjannie; Jensen, Frank B.; Huong, Do.T.T.; Wang, Tobias; Phuong, Nguyen T.; Bayley, Mark

    2011-01-01

    In this study we investigated nitrite (NO 2 - ) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO 2max ) and critical swimming speed (U crit ) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC 50 of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO 2max and U crit . The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO 2max and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

  16. Analyzing the dependence of oxygen incorporation current density on overpotential and oxygen partial pressure in mixed conducting oxide electrodes.

    Science.gov (United States)

    Guan, Zixuan; Chen, Di; Chueh, William C

    2017-08-30

    The oxygen incorporation reaction, which involves the transformation of an oxygen gas molecule to two lattice oxygen ions in a mixed ionic and electronic conducting solid, is a ubiquitous and fundamental reaction in solid-state electrochemistry. To understand the reaction pathway and to identify the rate-determining step, near-equilibrium measurements have been employed to quantify the exchange coefficients as a function of oxygen partial pressure and temperature. However, because the exchange coefficient contains contributions from both forward and reverse reaction rate constants and depends on both oxygen partial pressure and oxygen fugacity in the solid, unique and definitive mechanistic assessment has been challenging. In this work, we derive a current density equation as a function of both oxygen partial pressure and overpotential, and consider both near and far from equilibrium limits. Rather than considering specific reaction pathways, we generalize the multi-step oxygen incorporation reaction into the rate-determining step, preceding and following quasi-equilibrium steps, and consider the number of oxygen ions and electrons involved in each. By evaluating the dependence of current density on oxygen partial pressure and overpotential separately, one obtains the reaction orders for oxygen gas molecules and for solid-state species in the electrode. We simulated the oxygen incorporation current density-overpotential curves for praseodymium-doped ceria for various candidate rate-determining steps. This work highlights a promising method for studying the exchange kinetics far away from equilibrium.

  17. Genetic factors influencing ferritin levels in 14,126 blood donors

    DEFF Research Database (Denmark)

    Sørensen, Erik; Rigas, Andreas S; Thørner, Lise W

    2015-01-01

    BACKGROUND: Many biologic functions depend on sufficient iron levels, and iron deficiency is especially common among blood donors. Genetic variants associated with iron levels have been identified, but the impact of genetic variation on iron levels among blood donors remains unclear. STUDY DESIGN...... AND METHODS: The effect of six single-nucleotide polymorphisms (SNPs) on ferritin levels in 14,126 blood donors were investigated in four genes: in Human Hemochromatosis Protein gene (HFE; rs1800562 and rs179945); in Transmembrane Protease gene, Serine 6 (TMPRSS6-regulating hepcidin; rs855791); in BTB domain...... with iron deficiency in women. Results for all other genetic variants were insignificant. CONCLUSION: Genetic variants associated with hemochromatosis may protect donors against depleted iron stores. In addition, we showed that presence of the T-allele at rs855791 in TMPRSS6 was associated with lower iron...

  18. A system for oxygen-15 labeled blood for medical applications

    International Nuclear Information System (INIS)

    Subramanyam, R.; Bucelewicz, W.M.; Hoop, B. Jr.; Jones, S.C.

    1977-01-01

    Oxygen-15 labeled compounds in blood have been used successfully for cerebral circulation and cerebral oxygen metabolism measurements. The present paper describes a system for the rapid sequential production of 15 O-HgB, C 15 O-Hgb and H 2 15 O in blood under sterile and pyrogen-free conditions. A tonometer has been adopted for labeling blood without hemolysis and foam production. (author)

  19. Temperature Dependence of Apparent Respiratory Quotients and Oxygen Penetration Depth in Contrasting Lake Sediments

    Science.gov (United States)

    Sobek, Sebastian; Gudasz, Cristian; Koehler, Birgit; Tranvik, Lars J.; Bastviken, David; Morales-Pineda, María.

    2017-11-01

    Lake sediments constitute an important compartment in the carbon cycle of lakes, by burying carbon over geological timescales and by production and emission of greenhouse gases. The degradation of organic carbon (OC) in lake sediments is linked to both temperature and oxygen (O2), but the interactive nature of this regulation has not been studied in lake sediments in a quantitative way. We present the first systematic investigation of the effects of temperature on the apparent respiratory quotient (RQ, i.e., the molar ratio between carbon dioxide (CO2) production and O2 consumption) in two contrasting lake sediments. Laboratory incubations of sediment cores of a humic lake and an eutrophic lake across a 1-21°C temperature gradient over 157 days revealed that both CO2 production and O2 consumption were positively, exponentially, and similarly dependent on temperature. The apparent RQ differed significantly between the lake sediments (0.63 ± 0.26 and 0.99 ± 0.28 in the humic and the eutrophic lake, respectively; mean ± SD) and was significantly and positively related to temperature. The O2 penetration depth into the sediment varied by a factor of 2 over the 1-21°C temperature range and was significantly, negatively, and similarly related to temperature in both lake sediments. Accordingly, increasing temperature may influence the overall extent of OC degradation in lake sediments by limiting O2 supply to aerobic microbial respiration to the topmost sediment layer, resulting in a concomitant shift to less effective anaerobic degradation pathways. This suggests that temperature may represent a key controlling factor of the OC burial efficiency in lake sediments.

  20. Magnetic Resonance Imaging-Derived Renal Oxygenation and Perfusion During Continuous, Steady-State Angiotensin-II Infusion in Healthy Humans.

    Science.gov (United States)

    van der Bel, René; Coolen, Bram F; Nederveen, Aart J; Potters, Wouter V; Verberne, Hein J; Vogt, Liffert; Stroes, Erik S G; Krediet, C T Paul

    2016-03-28

    The role of kidney hypoxia is considered pivotal in the progression of chronic kidney disease. A widely used method to assess kidney oxygenation is blood oxygen level dependent (BOLD)-magnetic resonance imaging (MRI), but its interpretation remains problematic. The BOLD-MRI signal is the result of kidney oxygen consumption (a proxy of glomerular filtration) and supply (ie, glomerular perfusion). Therefore, we hypothesized that with pharmacological modulation of kidney blood flow, renal oxygenation, as assessed by BOLD-MRI, correlates to filtration fraction (ie, glomerular filtration rate/effective renal plasma flow) in healthy humans. Eight healthy volunteers were subjected to continuous angiotensin-II infusion at 0.3, 0.9, and 3.0 ng/kg per minute. At each dose, renal oxygenation and blood flow were assessed using BOLD and phase-contrast MRI. Subsequently, "gold standard" glomerular filtration rate/effective renal plasma flow measurements were performed under the same conditions. Renal plasma flow decreased dose dependently from 660±146 to 467±103 mL/min per 1.73 m(2) (F[3, 21]=33.3, PMRI, we showed that cortical oxygenation measured by BOLD MRI relates poorly to glomerular filtration rate but is associated with filtration fraction. For future studies, there may be a need to include renal plasma flow measurements when employing renal BOLD-MRI. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  1. Leukocyte and platelet depletion improves blood flow and function in a renal transplant model.

    Science.gov (United States)

    Yates, Phillip J; Hosgood, Sarah A; Nicholson, Michael L

    2012-01-01

    Donation after cardiac death (DCD) donors are an important source of organs for transplantation. Due to warm and cold ischemic injury, DCD kidneys undergo a significant reperfusion insult when transplanted. This is manifested clinically as a high incidence of delayed graft function (DGF) and primary non-function (PNF). The importance of leukocytes in the generation of reperfusion injury is pivotal. Using an ex vivo porcine model of kidney transplantation, the effects of reperfusion with leukocyte and platelet depleted blood (LDB) and whole blood (WB) on renal blood flow and function were compared. Hemodynamic measurements were recorded, and biochemical, hematological, and histologic samples taken at set time-points. Reperfusion with LDB improved renal blood flow significantly compared with WB reperfusion. In addition, there was a significant improvement in creatinine clearance and renal oxygen consumption, but not fractional excretion of sodium, acid-base homeostasis, urinary nitric oxide (NO), or 8-isoprostane levels. This study represents a good model for the initial reperfusion period in renal transplantation. Improvement in only some functional markers and neither urinary NO nor 8-isoprostane levels indicates that improved blood flow alone is not sufficient to reverse the severe ischemic insult endured by DCD kidneys. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Exercise capacity in the Bidirectional Glenn physiology: Coupling cardiac index, ventricular function and oxygen extraction ratio.

    Science.gov (United States)

    Vallecilla, Carolina; Khiabani, Reza H; Trusty, Phillip; Sandoval, Néstor; Fogel, Mark; Briceño, Juan Carlos; Yoganathan, Ajit P

    2015-07-16

    In Bi-directional Glenn (BDG) physiology, the superior systemic circulation and pulmonary circulation are in series. Consequently, only blood from the superior vena cava is oxygenated in the lungs. Oxygenated blood then travels to the ventricle where it is mixed with blood returning from the lower body. Therefore, incremental changes in oxygen extraction ratio (OER) could compromise exercise tolerance. In this study, the effect of exercise on the hemodynamic and ventricular performance of BDG physiology was investigated using clinical patient data as inputs for a lumped parameter model coupled with oxygenation equations. Changes in cardiac index, Qp/Qs, systemic pressure, oxygen extraction ratio and ventricular/vascular coupling ratio were calculated for three different exercise levels. The patient cohort (n=29) was sub-grouped by age and pulmonary vascular resistance (PVR) at rest. It was observed that the changes in exercise tolerance are significant in both comparisons, but most significant when sub-grouped by PVR at rest. Results showed that patients over 2 years old with high PVR are above or close to the upper tolerable limit of OER (0.32) at baseline. Patients with high PVR at rest had very poor exercise tolerance while patients with low PVR at rest could tolerate low exercise conditions. In general, ventricular function of SV patients is too poor to increase CI and fulfill exercise requirements. The presented mathematical model provides a framework to estimate the hemodynamic performance of BDG patients at different exercise levels according to patient specific data. Published by Elsevier Ltd.

  3. Oxygen affinity and Bohr effect responses to 2,3-diphosphoglycerate in equine and human blood.

    Science.gov (United States)

    diBella, G; Scandariato, G; Suriano, O; Rizzo, A

    1996-05-01

    The dependence of blood oxygen affinity and the Bohr effect on the concentration of 2,3-diphosphoglycerate (DPG) in erythrocytes was investigated in 24 trotter horses and 24 healthy men. The oxygen tension at half saturation and standard conditions (P50st at pH 7.4, PCO2(40) mmHg and 37 degrees C) and the carbon dioxide or fixed-acid-induced Bohr effect (dlogP50/dpH) were determined. Samples of fresh blood and blood depleted of or enriched with DPG were studied. In the absence of measurable DPG, the equine and human blood had similar mean (SD) values of P50st (16.6 [0.6] and 16.2 [0.7] mmHg, respectively). In both species these values increased with increasing DPG, but the response of equine blood was significantly lower, at least up to physiological values (P50st = 24.6 [0.6] and 26.2 [0.7]) mmHg; DPG = 14([1.8] and 12.8 [1.2] mumol gHb-1, respectively, in fresh blood). For concentrations above 20 to 25 mumol gHb-1 of DPG the difference between the values of P50st in the two species tended to decrease because the response in human blood reached a plateau. The interactions between the Bohr effect and the concentration of DPG showed that in the horses, as in the men, the level of DPG played an important role in governing the relative magnitude of carbon dioxide and fixed acid factors. The difference between them, which is associated with the oxylabile carbamino binding, was greatest in DPG-depleted blood, but whereas in the men the difference was suppressed by an above normal DPG concentration, in the horses it was still measurable.

  4. Spatially monitoring oxygen level in 3D microfabricated cell culture systems using optical oxygen sensing beads.

    Science.gov (United States)

    Wang, Lin; Acosta, Miguel A; Leach, Jennie B; Carrier, Rebecca L

    2013-04-21

    Capability of measuring and monitoring local oxygen concentration at the single cell level (tens of microns scale) is often desirable but difficult to achieve in cell culture. In this study, biocompatible oxygen sensing beads were prepared and tested for their potential for real-time monitoring and mapping of local oxygen concentration in 3D micro-patterned cell culture systems. Each oxygen sensing bead is composed of a silica core loaded with both an oxygen sensitive Ru(Ph2phen3)Cl2 dye and oxygen insensitive Nile blue reference dye, and a poly-dimethylsiloxane (PDMS) shell rendering biocompatibility. Human intestinal epithelial Caco-2 cells were cultivated on a series of PDMS and type I collagen based substrates patterned with micro-well arrays for 3 or 7 days, and then brought into contact with oxygen sensing beads. Using an image analysis algorithm to convert florescence intensity of beads to partial oxygen pressure in the culture system, tens of microns-size oxygen sensing beads enabled the spatial measurement of local oxygen concentration in the microfabricated system. Results generally indicated lower oxygen level inside wells than on top of wells, and local oxygen level dependence on structural features of cell culture surfaces. Interestingly, chemical composition of cell culture substrates also appeared to affect oxygen level, with type-I collagen based cell culture systems having lower oxygen concentration compared to PDMS based cell culture systems. In general, results suggest that oxygen sensing beads can be utilized to achieve real-time and local monitoring of micro-environment oxygen level in 3D microfabricated cell culture systems.

  5. Preliminary Study of Oxygen-Enhanced Longitudinal Relaxation in MRI: A Potential Novel Biomarker of Oxygenation Changes in Solid Tumors

    International Nuclear Information System (INIS)

    O'Connor, James P.B.; Naish, Josephine H.; Parker, Geoff J.M.; Waterton, John C.; Watson, Yvonne; Jayson, Gordon C.; Buonaccorsi, Giovanni A.; Cheung, Sue; Buckley, David L.; McGrath, Deirdre M.; West, Catharine M.L.; Davidson, Susan E.; Roberts, Caleb; Mills, Samantha J.; Mitchell, Claire L.; Hope, Lynn; Ton, N. Chan; Jackson, Alan

    2009-01-01

    Purpose: There is considerable interest in developing non-invasive methods of mapping tumor hypoxia. Changes in tissue oxygen concentration produce proportional changes in the magnetic resonance imaging (MRI) longitudinal relaxation rate (R 1 ). This technique has been used previously to evaluate oxygen delivery to healthy tissues and is distinct from blood oxygenation level-dependent (BOLD) imaging. Here we report application of this method to detect alteration in tumor oxygenation status. Methods and materials: Ten patients with advanced cancer of the abdomen and pelvis underwent serial measurement of tumor R 1 while breathing medical air (21% oxygen) followed by 100% oxygen (oxygen-enhanced MRI). Gadolinium-based dynamic contrast-enhanced MRI was then performed to compare the spatial distribution of perfusion with that of oxygen-induced ΔR 1 . Results: ΔR 1 showed significant increases of 0.021 to 0.058 s -1 in eight patients with either locally recurrent tumor from cervical and hepatocellular carcinomas or metastases from ovarian and colorectal carcinomas. In general, there was congruency between perfusion and oxygen concentration. However, regional mismatch was observed in some tumor cores. Here, moderate gadolinium uptake (consistent with moderate perfusion) was associated with low area under the ΔR 1 curve (consistent with minimal increase in oxygen concentration). Conclusions: These results provide evidence that oxygen-enhanced longitudinal relaxation can monitor changes in tumor oxygen concentration. The technique shows promise in identifying hypoxic regions within tumors and may enable spatial mapping of change in tumor oxygen concentration.

  6. Time-dependent correlation of cerebral blood flow with oxygen metabolism in activated human visual cortex as measured by fMRI.

    Science.gov (United States)

    Lin, Ai-Ling; Fox, Peter T; Yang, Yihong; Lu, Hanzhang; Tan, Li-Hai; Gao, Jia-Hong

    2009-01-01

    The aim of this study was to investigate the relationship between relative cerebral blood flow (delta CBF) and relative cerebral metabolic rate of oxygen (delta CMRO(2)) during continuous visual stimulation (21 min at 8 Hz) with fMRI biophysical models by simultaneously measuring of BOLD, CBF and CBV fMRI signals. The delta CMRO(2) was determined by both a newly calibrated single-compartment model (SCM) and a multi-compartment model (MCM) and was in agreement between these two models (P>0.5). The duration-varying delta CBF and delta CMRO(2) showed a negative correlation with time (r=-0.97, PSCM, an incorrect and even an opposite appearance of the flow-metabolism relationship during prolonged visual stimulation (positively linear coupling) can result. The time-dependent negative correlation between flow and metabolism demonstrated in this fMRI study is consistent with a previous PET observation and further supports the view that the increase in CBF is driven by factors other than oxygen demand and the energy demands will eventually require increased aerobic metabolism as stimulation continues.

  7. Brain activation studies with PET and functional MRI

    Energy Technology Data Exchange (ETDEWEB)

    Yonekura, Yoshiharu [Fukui Medical Univ., Matsuoka (Japan). Biomedical Imaging Research Center; Sadato, Norihiro [Okazaki National Research Inst., Aichi (Japan). National Inst. for Physiological Sciences

    2002-01-01

    Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H{sub 2}{sup 15}O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H{sub 2}{sup 15}O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

  8. Brain activation studies with PET and functional MRI

    International Nuclear Information System (INIS)

    Yonekura, Yoshiharu; Sadato, Norihiro

    2002-01-01

    Application of PET and functional MRI in brain activation studies is reviewed. 3D-PET images obtained repeatedly after intravenous injection of about 370 MBq of H 2 15 O can detect a faint blood flow change in the brain. Functional MRI can also detect the blood flow change in the brain due to blood oxygen level-dependent effect. Echo-planar imaging is popular in MRI with 1.5 or 3 T. Images are analyzed by statistical parametric mapping with correction of cerebral regions, anatomical normalization and statistics. PET data give the blood flow change by the H 2 15 O incorporation into the brain and MRI data, by the scarce tissue oxygen consumption despite the change. Actual images during the cognition task-performance and of frequent artifacts are given. PET is suitable for studies of brain functions like sensibility and emotion and functional MRI, like cortex functions and clinical practices in identification of functional regions prior to surgery and evaluation of functional recovery of damaged brain. (K.H.)

  9. Temperature effects on hemocyanin oxygen binding in an antarctic cephalopod.

    Science.gov (United States)

    Zielinski, S; Sartoris, F J; Pörtner, H O

    2001-02-01

    The functional relevance of oxygen transport by hemocyanin of the Antarctic octopod Megaleledone senoi and of the eurythermal cuttlefish Sepia officinalis was analyzed by continuous and simultaneous recordings of changes in pH and hemocyanin oxygen saturation in whole blood at various temperatures. These data were compared to literature data on other temperate and cold-water cephalopods (octopods and giant squid). In S. officinalis, the oxygen affinity of hemocyanin changed at deltaP50/degrees C = 0.12 kPa (pH 7.4) with increasing temperatures; this is similar to observations in temperate octopods. In M. senoi, thermal sensitivity was much smaller (delta log P50/delta pH) increased with increasing temperature in both the cuttlefish and the Antarctic octopod. At low PO2 (1.0 kPa) and pH (7.2), the presence of a large venous oxygen reserve (43% saturation) insensitive to pH reflects reduced pH sensitivity and high oxygen affinity in M. senoi hemocyanin at 0 degrees C. In S. officinalis, this reserve was 19% at pH 7.4, 20 degrees C, and 1.7 kPa O2, a level still higher than in squid. These findings suggest that the lower metabolic rate of octopods and cuttlefish compared to squid is reflected in less pH-dependent oxygen transport. Results of the hemocyanin analysis for the Antarctic octopod were similar to those reported for Vampyroteuthis--an extremely high oxygen affinity supporting a very low metabolic rate. In contrast to findings in cold-adapted giant squid, the minimized thermal sensitivity of oxygen transport in Antarctic octopods will reduce metabolic scope and thereby contribute to their stenothermality.

  10. Aerobic Physical Exercise Improved the Cognitive Function of Elderly Males but Did Not Modify Their Blood Homocysteine Levels

    Science.gov (United States)

    Antunes, Hanna Karen M.; De Mello, Marco Túlio; de Aquino Lemos, Valdir; Santos-Galduróz, Ruth Ferreira; Camargo Galdieri, Luciano; Amodeo Bueno, Orlando Francisco; Tufik, Sergio; D'Almeida, Vânia

    2015-01-01

    Background Physical exercise influences homocysteine (Hcy) concentrations, cognitive function and the metabolic profile. The purpose of this study was to investigate the influence of regular physical exercise on Hcy levels, the metabolic profile and cognitive function in healthy elderly males before and after an endurance exercise program. Methods Forty-five healthy and sedentary volunteers were randomized into 2 groups: (1) a control group asked not to change their normal everyday activities and not to start any regular physical exercise program and (2) an experimental group trained at a heart rate intensity corresponding to ventilatory threshold 1 (VT-1) for 60 min/day 3 times weekly on alternate days for 6 months using a cycle ergometer. All volunteers underwent cognitive evaluations, blood sample analyses and ergospirometric assessments. Results A significant improvement in cognitive function was observed in the experimental group compared with the control group (p 0.05), but there was a significant increase in peak oxygen consumption and workload at VT-1 as well as a significant improvement in cholesterol, triglycerides, HDL, glucose, alkaline phosphatase, urea, T3, T4 and prostate-specific antigen compared with the control group (p < 0.05). Conclusion The data suggest that a physical exercise program does not reduce Hcy levels in healthy elderly males, although it improves the cardiovascular and metabolic profile as well as cognitive function. PMID:25759715

  11. Cerebral blood flow response to functional activation

    DEFF Research Database (Denmark)

    Paulson, Olaf B; Hasselbalch, Steen G; Rostrup, Egill

    2010-01-01

    Cerebral blood flow (CBF) and cerebral metabolic rate are normally coupled, that is an increase in metabolic demand will lead to an increase in flow. However, during functional activation, CBF and glucose metabolism remain coupled as they increase in proportion, whereas oxygen metabolism only inc...... the cerebral tissue's increased demand for glucose supply during neural activation with recent evidence supporting a key function for astrocytes in rCBF regulation....

  12. An Fc engineering approach that modulates antibody-dependent cytokine release without altering cell-killing functions.

    Science.gov (United States)

    Kinder, Michelle; Greenplate, Allison R; Strohl, William R; Jordan, Robert E; Brezski, Randall J

    2015-01-01

    Cytotoxic therapeutic monoclonal antibodies (mAbs) often mediate target cell-killing by eliciting immune effector functions via Fc region interactions with cellular and humoral components of the immune system. Key functions include antibody-dependent cell-mediated cytotoxicity (ADCC), antibody-dependent cellular phagocytosis (ADCP), and complement-dependent cytotoxicity (CDC). However, there has been increased appreciation that along with cell-killing functions, the induction of antibody-dependent cytokine release (ADCR) can also influence disease microenvironments and therapeutic outcomes. Historically, most Fc engineering approaches have been aimed toward modulating ADCC, ADCP, or CDC. In the present study, we describe an Fc engineering approach that, while not resulting in impaired ADCC or ADCP, profoundly affects ADCR. As such, when peripheral blood mononuclear cells are used as effector cells against mAb-opsonized tumor cells, the described mAb variants elicit a similar profile and quantity of cytokines as IgG1. In contrast, although the variants elicit similar levels of tumor cell-killing as IgG1 with macrophage effector cells, the variants do not elicit macrophage-mediated ADCR against mAb-opsonized tumor cells. This study demonstrates that Fc engineering approaches can be employed to uncouple macrophage-mediated phagocytic and subsequent cell-killing functions from cytokine release.

  13. Changes in hemoglobin-oxygen affinity with shape variations of red blood cells

    Science.gov (United States)

    Chowdhury, Aniket; Dasgupta, Raktim; Majumder, Shovan K.

    2017-10-01

    Shape variations of red blood cells (RBCs) are known to occur upon exposure to various drugs or under diseased conditions. The commonly observed discocytic RBCs can be transformed to echinocytic or stomatocytic shape under such conditions. Raman spectra of the three major shape variations, namely discocyte, echinocyte, and stomatocyte, of RBCs were studied while subjecting the cells to oxygenated and deoxygenated conditions. Analysis of the recorded spectra suggests an increased level of hemoglobin (Hb)-oxygen affinity for the echinocytes. Also, some level of Hb degradation could be noticed for the deoxygenated echinocytes. The effects may arise from a reduced level of intracellular adenosine triphosphate in echinocytic cells and an increased fraction of submembrane Hb.

  14. In-vitro effects of tri-iodinated X-ray contrast media on blood coagulation, fibrinolysis and complement system

    International Nuclear Information System (INIS)

    Blanke, D.

    1982-01-01

    In-vitro experiments with Jodipamid, Jothalamat and Diatrizoat served the purpose of determining influences of contrast media on blood coagulation, fibrinolysis and the complement system. For all three contrast media investigated the effect noted was dose-dependent and was only brought about by concentrations higher than physiological ones. Liver-pathway Jodipamid was seen to have a much stronger effect than the two renal-pathway contrast media Jothalamat and Diatrizoat, which is probably due to the different protein binding capacities. In detail, the results with Jodipamid were as follows: a sharp fall in thrombinogen, a distinct decrease in fibrinogen both in the immunological and functional test, but only delayed decrease in complement factor C 4. Fibrinolytic fission products were found after applying the dose of 30 mM, as compared to 400 mM for the renal-pathway contrast media. Furthermore the functional tests (F I and F II) with Jothalamat and Diatrizoat showed only slight effects, the immunological ones (F I and C 4) none at all. The influence of the contrast media on factors I and II is interpreted by the author as an inhibition of fibrin polymerization. What seems to be the verification of fibrinolytic fission products is explained by a non-specific agglutination reaction, the decrease in C 4 by contrast-medium-induced protein denaturation. (orig./MG) [de

  15. Blood cadmium levels are associated with a decline in lung function in males

    International Nuclear Information System (INIS)

    Oh, Chang-Mo; Oh, In-Hwan; Lee, Jong-Keun; Park, Yoon Hyung; Choe, Bong-Keun; Yoon, Tai-Young; Choi, Joong-Myung

    2014-01-01

    Background: Cadmium exposure was found to cause a decline in lung function among the general population, but these findings were limited to smokers and gender differences were not explored. Objectives: To examine the relationship between cadmium and chronic obstructive pulmonary disease (COPD) according to gender and smoking status in Korea. Methods: Cross-sectional data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011 were analyzed. COPD was defined by a pre-bronchodilator forced expiratory volume in 1 s divided by forced vital capacity of <0.70. A logistic regression model was used to elucidate the association between blood cadmium levels and COPD according to gender and smoking status. Results: Among 3861 eligible participants, 3622 were included in the analysis. The prevalence of COPD demonstrated an increasing trend in males (P for trend<0.001), but not in females (P for trend=0.67). After adjusting for covariates, a higher blood cadmium level, but within the normal range, was associated with COPD in males, including those who had never-smoked (P for trend <0.001 and P for trend=0.008). However, a higher blood cadmium level was not significantly associated with COPD in females, including those who had never smoked (P for trend=0.39 and P for trend=0.43). Conclusions: A higher blood cadmium level, within the normal range, was associated with COPD in males, including those who had never smoked. However, there was no significant association between blood cadmium levels and COPD in females. - Highlights: • Elevated blood cadmium level is associated with chronic obstructive pulmonary disease in male. • This association can be seen even in never smoked male. • However, this association is present only in male, but not in female

  16. Blood cadmium levels are associated with a decline in lung function in males

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Chang-Mo [Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); The Korea Central Cancer Registry, National Cancer Center, Goyang (Korea, Republic of); Oh, In-Hwan; Lee, Jong-Keun [Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Park, Yoon Hyung [Departments of Preventive Medicine, School of Medicine, Soonchunhyang University, Seoul (Korea, Republic of); Choe, Bong-Keun; Yoon, Tai-Young [Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of); Choi, Joong-Myung, E-mail: jmchoi@khu.ac.kr [Department of Preventive Medicine, School of Medicine, Kyung Hee University, Seoul 130-701 (Korea, Republic of)

    2014-07-15

    Background: Cadmium exposure was found to cause a decline in lung function among the general population, but these findings were limited to smokers and gender differences were not explored. Objectives: To examine the relationship between cadmium and chronic obstructive pulmonary disease (COPD) according to gender and smoking status in Korea. Methods: Cross-sectional data from the Korean National Health and Nutrition Examination Survey from 2008 to 2011 were analyzed. COPD was defined by a pre-bronchodilator forced expiratory volume in 1 s divided by forced vital capacity of <0.70. A logistic regression model was used to elucidate the association between blood cadmium levels and COPD according to gender and smoking status. Results: Among 3861 eligible participants, 3622 were included in the analysis. The prevalence of COPD demonstrated an increasing trend in males (P for trend<0.001), but not in females (P for trend=0.67). After adjusting for covariates, a higher blood cadmium level, but within the normal range, was associated with COPD in males, including those who had never-smoked (P for trend <0.001 and P for trend=0.008). However, a higher blood cadmium level was not significantly associated with COPD in females, including those who had never smoked (P for trend=0.39 and P for trend=0.43). Conclusions: A higher blood cadmium level, within the normal range, was associated with COPD in males, including those who had never smoked. However, there was no significant association between blood cadmium levels and COPD in females. - Highlights: • Elevated blood cadmium level is associated with chronic obstructive pulmonary disease in male. • This association can be seen even in never smoked male. • However, this association is present only in male, but not in female.

  17. Cerebral interstitial tissue oxygen tension, pH, HCO3, CO2.

    Science.gov (United States)

    Charbel, F T; Hoffman, W E; Misra, M; Hannigan, K; Ausman, J I

    1997-10-01

    There are many techniques for monitoring the injured brain following trauma, subarachnoid hemorrhage, or surgery. It is thought that the major determinants for recovery of injured cerebral tissue are oxygen, glucose delivery, and the clearance of metabolites. These factors, at optimal levels, are probably responsible for the regaining of neuronal functions. These parameters are in turn dependent on the tissue's blood flow and metabolism. We have been using a single, compact, polyethylene sensor, the Paratrend 7 for the measurement of cerebral oxygen tension, CO2, pH, and temperature. This sensor is designed for continuous blood gas analysis to aid in monitoring neurosurgical patients, both during surgery and in the intensive care unit. Using the Paratrend 7 sensor, we found the normal range of values to be: PO2 33 +/- 11 mm Hg; PCO2 48 +/- 7 mm Hg; pH 7.19 +/- 0.11. Critical measurements are considered to be tissue PO2 60 mm Hg, and pH effective method of measuring tissue cerebral oxygen tension, along with carbon dioxide levels, pH, and temperature.

  18. Noninvasive optical quantification of absolute blood flow, blood oxygenation, and oxygen consumption rate in exercising skeletal muscle

    Science.gov (United States)

    Gurley, Katelyn; Shang, Yu; Yu, Guoqiang

    2012-07-01

    This study investigates a method using novel hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] to obtain continuous, noninvasive measurement of absolute blood flow (BF), blood oxygenation, and oxygen consumption rate (\\Vdot O2) in exercising skeletal muscle. Healthy subjects (n=9) performed a handgrip exercise to increase BF and \\Vdot O2 in forearm flexor muscles, while a hybrid optical probe on the skin surface directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and THC), tissue oxygen saturation (StO2), relative BF (rBF), and relative oxygen consumption rate (r\\Vdot O2). The rBF and r\\Vdot O2 signals were calibrated with absolute baseline BF and \\Vdot O2 obtained through venous and arterial occlusions, respectively. Known problems with muscle-fiber motion artifacts in optical measurements during exercise were mitigated using a novel gating algorithm that determined muscle contraction status based on control signals from a dynamometer. Results were consistent with previous findings in the literature. This study supports the application of NIRS/DCS technology to quantitatively evaluate hemodynamic and metabolic parameters in exercising skeletal muscle and holds promise for improving diagnosis and treatment evaluation for patients suffering from diseases affecting skeletal muscle and advancing fundamental understanding of muscle and exercise physiology.

  19. Renal Tissue Oxygenation in Essential Hypertension and Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Menno Pruijm

    2013-01-01

    Full Text Available Animal studies suggest that renal tissue hypoxia plays an important role in the development of renal damage in hypertension and renal diseases, yet human data were scarce due to the lack of noninvasive methods. Over the last decade, blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI, detecting deoxyhemoglobin in hypoxic renal tissue, has become a powerful tool to assess kidney oxygenation noninvasively in humans. This paper provides an overview of BOLD-MRI studies performed in patients suffering from essential hypertension or chronic kidney disease (CKD. In line with animal studies, acute changes in cortical and medullary oxygenation have been observed after the administration of medication (furosemide, blockers of the renin-angiotensin system or alterations in sodium intake in these patient groups, underlining the important role of renal sodium handling in kidney oxygenation. In contrast, no BOLD-MRI studies have convincingly demonstrated that renal oxygenation is chronically reduced in essential hypertension or in CKD or chronically altered after long-term medication intake. More studies are required to clarify this discrepancy and to further unravel the role of renal oxygenation in the development and progression of essential hypertension and CKD in humans.

  20. Decreased serum level of NGF in alcohol-dependent patients with declined executive function

    Directory of Open Access Journals (Sweden)

    Bae H

    2014-11-01

    Full Text Available Hwallip Bae,1 Youngsun Ra,1 Changwoo Han,2 Dai-Jin Kim3 1Department of Psychiatry, Myongji Hospital, Goyang, 2Department of Psychiatry, Keyo Hospital, Uiwang, 3Department of Psychiatry, Seoul St Mary’s Hospital, College of Medicine, Catholic University of Korea, Seoul, South Korea Abstract: The role of neurotrophic factors has been highlighted as a cause of decline in the cognitive function of alcohol-dependent patients. It is known that nerve-growth factor (NGF, one of the neurotrophins, is related to the growth and differentiation of nerve cells, as well as to a decline in cognitive function. The purpose of this study was to investigate the relationship between decreased NGF levels and cognitive decline in alcohol-dependent patients. The serum concentration of NGF was measured in 38 patients with chronic alcohol dependence, and several neuropsychological tests were also performed for cognitive function assessment. The results indicated a significant correlation between serum NGF level and the trail-making test part B, which evaluates executive function, but did not show a significant correlation with other cognitive function tests. An increased serum level of NGF was associated with a decreased completion time in the trail-making test B, and this finding indicates that a high serum level of NGF is related to greater executive function. This finding may imply a protective role of NGF in preventing neuron damage among patients with alcohol dependence. Larger controlled studies will be necessary in the future to investigate this issue further. Keywords: nerve-growth factor, alcohol dependence, executive function, trail-making test

  1. Study on the relationship between peripheral blood red blood cells imuno-function status and serum gastrin level in patients with peptic ulcer

    International Nuclear Information System (INIS)

    Li Qin; Fan Rong; Luo Honglai; Wang Ying; Tao Liangliang; Wang Zhenkai

    2011-01-01

    Objective: To explore the relationship between changes of peripheral blood red blood cells immuno-function status and serum gastrin level in patients with peptic ulcer. Methods: RBC immuno-function status was studied with immune methods and serum gastrin level was measured with RIA in 51 patients with peptic ulcer and compared with 35 healthy control group. Results: RBC-C3bRR percentage was significantly lower in patients with peptic ulcer than that in controls (P<0.01), while serum gastrin level was significantly higher (P<0.01). RBC-C3bRR was significantly nagatively correlated to serum gastrin (r=-0.3828, P<0.01). RBC-ICRRR percentage was prominently higher than that in healthy controls (P<0.01), and RBC-ICRRR was positively correlated to serum gastrin level (r=0.4185, P<0.01). Conclusion: There were disturbance of RBC immune-regulation with suppressed immune function and higher gastrin levels in patients with peptic ulcer. (authors)

  2. Feed-derived volatile basic nitrogen increases reactive oxygen species production of blood leukocytes in lactating dairy cows.

    Science.gov (United States)

    Tsunoda, Ei; Gross, Josef J; Kawashima, Chiho; Bruckmaier, Rupert M; Kida, Katsuya; Miyamoto, Akio

    2017-01-01

    The present study investigated over 9 months the changes of fermentative quality of total mixed rations (TMR) containing grass silage (GS) as a major component, associated with changes in the volatile basic nitrogen (VBN) levels in an experimental dairy farm. Effects of VBN levels in TMR on metabolic parameters, reactive oxygen species (ROS) production by blood polymorphonuclear leukocytes (PMNs) and conception rates for dairy cows were analyzed. According to VBN levels in TMR during survey periods, three distinct phases were identified; phase A with low VBN; phase B with high VBN; and phase C with mid-VBN. Metabolic parameters in blood were all within normal range. However, during phases B and C, nitrogen metabolic indices such as blood urea nitrogen and milk urea nitrogen showed higher levels compared to those in phase A, and a simultaneous increase in ROS production by blood PMNs and the load on hepatic function in metabolic parameters was observed in the cows with a lower conception rate. This suggests that feeding TMR with elevated VBN levels due to poor fermented GS results in stimulation of ROS production by PMNs by ammonia, and negatively affects metabolism and reproductive performance in lactating dairy cow. © 2016 Japanese Society of Animal Science.

  3. Effect of streptozotocin-induced diabetes on myocardial blood flow reserve assessed by myocardial contrast echocardiography in rats

    Directory of Open Access Journals (Sweden)

    Weytjens Caroline

    2008-09-01

    Full Text Available Abstract The role of structural and functional abnormalities of small vessels in diabetes cardiomyopathy remains unclear. Myocardial contrast echocardiography allows the quantification of myocardial blood flow at rest and during dipyridamole infusion. The aim of the study was to determine the myocardial blood flow reserve in normal rats compared with Streptozotocin-induced diabetic rats using contrast echocardiography. Methods We prospectively studied 40 Wistar rats. Diabetes was induced by intravenous streptozotocin in 20 rats. All rats underwent baseline and stress (dipyridamole: 20 mg/kg high power intermittent imaging in short axis view under anaesthesia baseline and after six months. Myocardial blood flow was determined and compared at rest and after dipyridamole in both populations. The myocardial blood flow reserve was calculated and compared in the 2 groups. Parameters of left ventricular function were determined from the M-mode tracings and histological examination was performed in all rats at the end of the study. Results At six months, myocardial blood flow reserve was significantly lower in diabetic rats compared to controls (3.09 ± 0.98 vs. 1.28 ± 0.67 ml min-1 g-1; p Conclusion In this animal study, diabetes induced a functional alteration of the coronary microcirculation, as demonstrated by contrast echocardiography, a decrease in capillary density and of the cardiac systolic function. These findings may offer new insights into the underlying mechanisms of diabetes cardiomyopathy.

  4. Contrast-enhanced MRI of the lung

    International Nuclear Information System (INIS)

    Kauczor, Hans-Ulrich; Kreitner, Karl-Friedrich

    2000-01-01

    The lung has long been neglected by MR imaging. This is due to unique intrinsic difficulties: (1) signal loss due to cardiac pulsation and respiration; (2) susceptibility artifacts caused by multiple air-tissue interfaces; (3) low proton density. There are many MR strategies to overcome these problems. They consist of breath-hold imaging, respiratory and cardiac gating procedures, use of short repetition and echo times, increase of the relaxivity of existing spins by administration of intravenous contrast agents, and enrichment of spin density by hyperpolarized noble gases or oxygen. Improvements in scanner performance and frequent use of contrast media have increased the interest in MR imaging and MR angiography of the lung. They can be used on a routine basis for the following indications: characterization of pulmonary nodules, staging of bronchogenic carcinoma, in particular assessment of chest wall invasion; evaluation of inflammatory activity in interstitial lung disease; acute pulmonary embolism, chronic thromboembolic pulmonary hypertension, vascular involvement in malignant disease; vascular abnormalities. Future perspectives include perfusion imaging using extracellular or intravascular (blood pool) contrast agents and ventilation imaging using inhalation of hyperpolarized noble gases, of paramagnetic oxygen or of aerosolized contrast agents. These techniques represent new approaches to functional lung imaging. The combination of visualization of morphology and functional assessment of ventilation and perfusion is unequalled by any other technique

  5. Glucose Transporters at the Blood-Brain Barrier: Function, Regulation and Gateways for Drug Delivery.

    Science.gov (United States)

    Patching, Simon G

    2017-03-01

    Glucose transporters (GLUTs) at the blood-brain barrier maintain the continuous high glucose and energy demands of the brain. They also act as therapeutic targets and provide routes of entry for drug delivery to the brain and central nervous system for treatment of neurological and neurovascular conditions and brain tumours. This article first describes the distribution, function and regulation of glucose transporters at the blood-brain barrier, the major ones being the sodium-independent facilitative transporters GLUT1 and GLUT3. Other GLUTs and sodium-dependent transporters (SGLTs) have also been identified at lower levels and under various physiological conditions. It then considers the effects on glucose transporter expression and distribution of hypoglycemia and hyperglycemia associated with diabetes and oxygen/glucose deprivation associated with cerebral ischemia. A reduction in glucose transporters at the blood-brain barrier that occurs before the onset of the main pathophysiological changes and symptoms of Alzheimer's disease is a potential causative effect in the vascular hypothesis of the disease. Mutations in glucose transporters, notably those identified in GLUT1 deficiency syndrome, and some recreational drug compounds also alter the expression and/or activity of glucose transporters at the blood-brain barrier. Approaches for drug delivery across the blood-brain barrier include the pro-drug strategy whereby drug molecules are conjugated to glucose transporter substrates or encapsulated in nano-enabled delivery systems (e.g. liposomes, micelles, nanoparticles) that are functionalised to target glucose transporters. Finally, the continuous development of blood-brain barrier in vitro models is important for studying glucose transporter function, effects of disease conditions and interactions with drugs and xenobiotics.

  6. Volume-dependent K+ transport in rabbit red blood cells comparison with oxygenated human SS cells

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rohil, N.; Jennings, M.L.

    1989-07-01

    In this study the volume-dependent or N-ethylmaleimide (NEM)-stimulated, ouabain-insensitive K+ influx and efflux were measured with the tracer 86Rb+ in rabbit red blood cells. The purpose of the work was to examine the rabbit as a potential model for cell volume regulation in human SS red blood cells and also to investigate the relationship between the NEM-reactive sulfhydryl group(s) and the signal by which cell swelling activates the transport. Ouabain-resistant K+ efflux and influx increase nearly threefold in cells swollen hypotonically by 15%. Pretreatment with 2 mM NEM stimulates efflux 5-fold and influx 10-fold (each measured in an isotonic medium). The ouabain-resistant K+ efflux was dependent on the major anion in the medium. The anion dependence of K+ efflux in swollen or NEM-stimulated cells was as follows: Br- greater than Cl- much greater than NO3- = acetate. The magnitudes of both the swelling- and the NEM-stimulated fluxes are much higher in young cells (density separated but excluding reticulocytes) than in older cells. Swelling- or NEM-stimulated K+ efflux in rabbit red blood cells was inhibited 50% by 1 mM furosemide, and the inhibitory potency of furosemide was enhanced by extracellular K+, as is known to be true for human AA and low-K+ sheep red blood cells. The swelling-stimulated flux in both rabbit and human SS cells has a pH optimum at approximately 7.4. We conclude that rabbit red blood cells are a good model for swelling-stimulated K+ transport in human SS cells.

  7. Assessing sensory versus optogenetic network activation by combining (o)fMRI with optical Ca2+ recordings.

    Science.gov (United States)

    Schmid, Florian; Wachsmuth, Lydia; Schwalm, Miriam; Prouvot, Pierre-Hugues; Jubal, Eduardo Rosales; Fois, Consuelo; Pramanik, Gautam; Zimmer, Claus; Faber, Cornelius; Stroh, Albrecht

    2016-11-01

    Encoding of sensory inputs in the cortex is characterized by sparse neuronal network activation. Optogenetic stimulation has previously been combined with fMRI (ofMRI) to probe functional networks. However, for a quantitative optogenetic probing of sensory-driven sparse network activation, the level of similarity between sensory and optogenetic network activation needs to be explored. Here, we complement ofMRI with optic fiber-based population Ca 2+ recordings for a region-specific readout of neuronal spiking activity in rat brain. Comparing Ca 2+ responses to the blood oxygenation level-dependent signal upon sensory stimulation with increasing frequencies showed adaptation of Ca 2+ transients contrasted by an increase of blood oxygenation level-dependent responses, indicating that the optical recordings convey complementary information on neuronal network activity to the corresponding hemodynamic response. To study the similarity of optogenetic and sensory activation, we quantified the density of cells expressing channelrhodopsin-2 and modeled light propagation in the tissue. We estimated the effectively illuminated volume and numbers of optogenetically stimulated neurons, being indicative of sparse activation. At the functional level, upon either sensory or optogenetic stimulation we detected single-peak short-latency primary Ca 2+ responses with similar amplitudes and found that blood oxygenation level-dependent responses showed similar time courses. These data suggest that ofMRI can serve as a representative model for functional brain mapping. © The Author(s) 2015.

  8. Assessing sensory versus optogenetic network activation by combining (o)fMRI with optical Ca2+ recordings

    Science.gov (United States)

    Schmid, Florian; Wachsmuth, Lydia; Schwalm, Miriam; Prouvot, Pierre-Hugues; Jubal, Eduardo Rosales; Fois, Consuelo; Pramanik, Gautam; Zimmer, Claus; Stroh, Albrecht

    2015-01-01

    Encoding of sensory inputs in the cortex is characterized by sparse neuronal network activation. Optogenetic stimulation has previously been combined with fMRI (ofMRI) to probe functional networks. However, for a quantitative optogenetic probing of sensory-driven sparse network activation, the level of similarity between sensory and optogenetic network activation needs to be explored. Here, we complement ofMRI with optic fiber-based population Ca2+ recordings for a region-specific readout of neuronal spiking activity in rat brain. Comparing Ca2+ responses to the blood oxygenation level-dependent signal upon sensory stimulation with increasing frequencies showed adaptation of Ca2+ transients contrasted by an increase of blood oxygenation level-dependent responses, indicating that the optical recordings convey complementary information on neuronal network activity to the corresponding hemodynamic response. To study the similarity of optogenetic and sensory activation, we quantified the density of cells expressing channelrhodopsin-2 and modeled light propagation in the tissue. We estimated the effectively illuminated volume and numbers of optogenetically stimulated neurons, being indicative of sparse activation. At the functional level, upon either sensory or optogenetic stimulation we detected single-peak short-latency primary Ca2+ responses with similar amplitudes and found that blood oxygenation level-dependent responses showed similar time courses. These data suggest that ofMRI can serve as a representative model for functional brain mapping. PMID:26661247

  9. Generation of erythroid cells from polyploid giant cancer cells: re-thinking about tumor blood supply.

    Science.gov (United States)

    Yang, Zhigang; Yao, Hong; Fei, Fei; Li, Yuwei; Qu, Jie; Li, Chunyuan; Zhang, Shiwu

    2018-04-01

    During development and tumor progression, cells need a sufficient blood supply to maintain development and rapid growth. It is reported that there are three patterns of blood supply for tumor growth: endothelium-dependent vessels, mosaic vessels, and vasculogenic mimicry (VM). VM was first reported in highly aggressive uveal melanomas, with tumor cells mimicking the presence and function of endothelial cells forming the walls of VM vessels. The walls of mosaic vessels are randomly lined with both endothelial cells and tumor cells. We previously proposed a three-stage process, beginning with VM, progressing to mosaic vessels, and eventually leading to endothelium-dependent vessels. However, many phenomena unique to VM channel formation remain to be elucidated, such as the origin of erythrocytes before VM vessels connect with endothelium-dependent vessels. In adults, erythroid cells are generally believed to be generated from hematopoietic stem cells in the bone marrow. In contrast, embryonic tissue obtains oxygen through formation of blood islands, which are largely composed of embryonic hemoglobin with a higher affinity with oxygen, in the absence of mature erythrocytes. Recent data from our laboratory suggest that embryonic blood-forming mechanisms also exist in cancer tissue, particularly when these tissues are under environmental stress such as hypoxia. We review the evidence from induced pluripotent stem cells in vitro and in vivo to support this previously underappreciated cell functionality in normal and cancer cells, including the ability to generate erythroid cells. We will also summarize the current understanding of tumor angiogenesis, VM, and our recent work on polyploid giant cancer cells, with emphasis on their ability to generate erythroid cells and their association with tumor growth under hypoxia. An alternative embryonic pathway to obtain oxygen in cancer cells exists, particularly when they are under hypoxic conditions.

  10. Blood oxygen and carbon dioxide transport in man

    OpenAIRE

    McElderry, Linda A.

    1981-01-01

    The effect of long term domiciliary oxygen therapy on the position and shape of the oxygen dissociation curve, together with other haematologic variables such as 2,3- diphosphoglycerate (2,3-DPG), haemoglobin concentration, packed cell volume, mean corpuscular haemoglobin concentration, and arterial blood gas and pH values, has been studied in patients with chronic bronchitis. Twenty-six patients were randomly allocated to receive either no oxygen therapy or 15 hours p...

  11. Oxygenation level and hemoglobin concentration in experimental tumor estimated by diffuse optical spectroscopy

    Science.gov (United States)

    Orlova, A. G.; Kirillin, M. Yu.; Volovetsky, A. B.; Shilyagina, N. Yu.; Sergeeva, E. A.; Golubiatnikov, G. Yu.; Turchin, I. V.

    2017-07-01

    Using diffuse optical spectroscopy the level of oxygenation and hemoglobin concentration in experimental tumor in comparison with normal muscle tissue of mice have been studied. Subcutaneously growing SKBR-3 was used as a tumor model. Continuous wave fiber probe diffuse optical spectroscopy system was employed. Optical properties extraction approach was based on diffusion approximation. Decreased blood oxygen saturation level and increased total hemoglobin content were demonstrated in the neoplasm. The main reason of such differences between tumor and norm was significant elevation of deoxyhemoglobin concentration in SKBR-3. The method can be useful for diagnosis of tumors as well as for study of blood flow parameters of tumor models with different angiogenic properties.

  12. Exploring Secondary Students' Epistemological Features Depending on the Evaluation Levels of the Group Model on Blood Circulation

    Science.gov (United States)

    Lee, Shinyoung; Kim, Heui-Baik

    2014-01-01

    The purpose of this study is to identify the epistemological features and model qualities depending on model evaluation levels and to explore the reasoning process behind high-level evaluation through small group interaction about blood circulation. Nine groups of three to four students in the eighth grade participated in the modeling practice.…

  13. Thermal dependence of ultrasound contrast agents scattering efficiency for echographic imaging techniques

    Science.gov (United States)

    Biagioni, Angelo; Bettucci, Andrea; Passeri, Daniele; Alippi, Adriano

    2015-06-01

    Ultrasound contrast agents are used in echographic imaging techniques to enhance image contrast. In addition, they may represent an interesting solution to the problem of non-invasive temperature monitoring inside the human body, based on some thermal variations of their physical properties. Contrast agents, indeed, are inserted into blood circulation and they reach the most important organs inside the human body; consequently, any thermometric property that they may possess, could be exploited for realizing a non-invasive thermometer. They essentially are a suspension of microbubbles containing a gas enclosed in a phospholipid membrane; temperature variations induce structural modifications of the microbubble phospholipid shell, thus causing thermal dependence of contrast agent's elastic characteristics. In this paper, the acoustic scattering efficiency of a bulk suspension of of SonoVue® (Bracco SpA Milan, Italy) has been studied using a pulse-echo technique in the frequency range 1-17 MHz, as it depends upon temperatures between 25 and 65°C. Experimental data confirm that the ultrasonic attenuation coefficient of SonoVue® depends on temperature between 25 and 60°C. Chemical composition of the bubble shell seem to support the hypothesis that a phase transition in the microstructure of lipid-coated microbubbles could play a key role in explaining such effect.

  14. Anaerobic nitrogen turnover by sinking diatom aggregates at varying ambient oxygen levels

    DEFF Research Database (Denmark)

    Stief, Peter; Kamp, Anja; Thamdrup, Bo

    2016-01-01

    nitrate supply. Sinking diatom aggregates can contribute directly to fixed-nitrogen loss in low-oxygen environments in the ocean and vastly expand the ocean volume in which anaerobic nitrogen turnover is possible, despite relatively high ambient oxygen levels. Depending on the extent of intracellular......In the world’s oceans, even relatively low oxygen levels inhibit anaerobic nitrogen cycling by free-living microbes. Sinking organic aggregates, however, might provide oxygen-depleted microbial hotspots in otherwise oxygenated surface waters. Here, we show that sinking diatom aggregates can host...

  15. Left ventricular dysfunction and blood glycohemoglobin levels in young diabetics

    Energy Technology Data Exchange (ETDEWEB)

    Aydiner, A.; Oto, A.; Oram, E.; Oram, A.; Ugurlu, S.; Karamehmetoglu, A. (Hacettepe Univ., Ankara (Turkey). Dept. of Cardiology); Aras, T.; Bekdik, C.F. (Hacettepe Univ., Ankara (Turkey). Dept. of Nuclear Medicine); Gedik, O. (Hacettepe Univ., Ankara (Turkey). Dept. of Endocrinology)

    1991-10-01

    Left ventricular function including regional wall motion (RWM) was evaluated by {sup 99m}Tc first-pass and equilibrium gated blood pool ventriculography and glycohemoglobin (HbA1c) blood levels determined by a quantitative column technique in 25 young patients with insulin-dependent diabetes mellitus without clinical evidence of heart diesease, and in healthy controls matched for age and sex. Phase analysis revealed abnormal RWM in 19 of 21 diabetic patients. The mean left ventricular global ejection fraction, the mean regional ejection fraction and the mean 1/3 filling fraction were lower and the time to peak ejection, the time to peak filling and the time to peak ejection/cardiac cycle were longer in diabetics than in controls. We found high HbA1c levels in all diabetics. There was no significant difference between patients with and without retinopathy and with and without peripheral neuropathy in terms of left ventricular function and HbA1c levels. (orig.).

  16. Left ventricular dysfunction and blood glycohemoglobin levels in young diabetics

    International Nuclear Information System (INIS)

    Aydiner, A.; Oto, A.; Oram, E.; Oram, A.; Ugurlu, S.; Karamehmetoglu, A.; Aras, T.; Bekdik, C.F.; Gedik, O.

    1991-01-01

    Left ventricular function including regional wall motion (RWM) was evaluated by 99m Tc first-pass and equilibrium gated blood pool ventriculography and glycohemoglobin (HbA1c) blood levels determined by a quantitative column technique in 25 young patients with insulin-dependent diabetes mellitus without clinical evidence of heart diesease, and in healthy controls matched for age and sex. Phase analysis revealed abnormal RWM in 19 of 21 diabetic patients. The mean left ventricular global ejection fraction, the mean regional ejection fraction and the mean 1/3 filling fraction were lower and the time to peak ejection, the time to peak filling and the time to peak ejection/cardiac cycle were longer in diabetics than in controls. We found high HbA1c levels in all diabetics. There was no significant difference between patients with and without retinopathy and with and without peripheral neuropathy in terms of left ventricular function and HbA1c levels. (orig.) [de

  17. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

    International Nuclear Information System (INIS)

    Zheng, Gang; Lou, Yaxian; Pan, Zhiying; Liu, Ya; Wen, Jiqiu; Li, Xue; Zhang, Zhe; Lu, Hanzhang; Liu, Wei; Liu, Hui; Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming

    2016-01-01

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO 2 ) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO 2 was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min -1 100 g -1 , P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO 2 (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O 2 min -1 100 g -1 , P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO 2 . Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO 2 . There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO 2 . Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  18. Diffuse reflectance spectroscopy for the measurement of tissue oxygen saturation

    International Nuclear Information System (INIS)

    Sircan-Kucuksayan, A; Canpolat, M; Uyuklu, M

    2015-01-01

    Tissue oxygen saturation (StO 2 ) is a useful parameter for medical applications. A spectroscopic method has been developed to detect pathologic tissues, due to a lack of normal blood circulation, by measuring StO 2 . In this study, human blood samples with different levels of oxygen saturation have been prepared and spectra were acquired using an optical fiber probe to investigate the correlation between the oxygen saturation levels and the spectra. A linear correlation between the oxygen saturation and ratio of the intensities (760 nm to 790 nm) of the spectra acquired from blood samples has been found. In a validation study, oxygen saturations of the blood samples were estimated from the spectroscopic measurements with an error of 2.9%. It has also been shown that the linear dependence between the ratio and the oxygen saturation of the blood samples was valid for the blood samples with different hematocrits. Spectra were acquired from the forearms of 30 healthy volunteers to estimate StO 2 prior to, at the beginning of, after 2 min, and at the release of total vascular occlusion. The average StO 2 of a forearm before and after the two minutes occlusion was significantly different. The results suggested that optical reflectance spectroscopy is a sensitive method to estimate the StO 2 levels of human tissue. The technique developed to measure StO 2 has potential to detect ischemia in real time. (paper)

  19. Physiological basis and image processing in functional magnetic resonance imaging: Neuronal and motor activity in brain

    Directory of Open Access Journals (Sweden)

    Sharma Rakesh

    2004-05-01

    Full Text Available Abstract Functional magnetic resonance imaging (fMRI is recently developing as imaging modality used for mapping hemodynamics of neuronal and motor event related tissue blood oxygen level dependence (BOLD in terms of brain activation. Image processing is performed by segmentation and registration methods. Segmentation algorithms provide brain surface-based analysis, automated anatomical labeling of cortical fields in magnetic resonance data sets based on oxygen metabolic state. Registration algorithms provide geometric features using two or more imaging modalities to assure clinically useful neuronal and motor information of brain activation. This review article summarizes the physiological basis of fMRI signal, its origin, contrast enhancement, physical factors, anatomical labeling by segmentation, registration approaches with examples of visual and motor activity in brain. Latest developments are reviewed for clinical applications of fMRI along with other different neurophysiological and imaging modalities.

  20. Myocardial Blood Volume Is Associated with Myocardial Oxygen Consumption: An Experimental Study with CMR in a Canine Model

    Science.gov (United States)

    McCommis, Kyle S.; Zhang, Haosen; Goldstein, Thomas A.; Misselwitz, Bernd; Abendschein, Dana R.; Gropler, Robert J.; Zheng, Jie

    2009-01-01

    OBJECTIVES To evaluate the feasibility of cardiovascular MR (CMR) to determine regional myocardial perfusion and O2 metabolism, and assess the role of myocardial blood volume (MBV) on oxygen supply. BACKGROUND Coronary artery disease presents as an imbalance of myocardial oxygen supply and demand. We have developed relevant CMR methods to determine the relationship of myocardial blood flow (MBF) and MBV to oxygen consumption (MVO2) during pharmacologic hyperemia. METHODS Twenty-one mongrel dogs were studied with varying stenosis severities imposed on the proximal left anterior descending (LAD) coronary artery. MBF and MBV were determined by CMR first-pass perfusion, while the oxygen extraction fraction (OEF) and MVO2 were determined by the myocardial Blood-Oxygen-Level-Dependent (BOLD) effect and Fick’s law, respectively. MR imaging was performed at rest, and during either dipyridamole-induced vasodilation or dobutamine-induced hyperemia. Regional differences in myocardial perfusion and oxygenation were then evaluated. RESULTS Dipyridamole and dobutamine both led to 145–200% increases in MBF and 50–80% increases in MBV in normal perfused myocardium. As expected, MVO2 increased more significantly with dobutamine (~175%) than dipyridamole (~40%). Coronary stenosis resulted in an attenuation of MBF, MBV, and MVO2 in both the LAD-subtended stenosis region and the left circumflex subtended remote region. Liner regression analysis showed that MBV reserve appears to be more correlated with MVO2 reserve during dobutamine stress than MBF reserve, particularly in the stenotic regions. Conversely, MBF reserve appears to be more correlated with MVO2 reserve during dipyridamole, although neither of these differences was significant. CONCLUSIONS Noninvasive evaluation of both myocardial perfusion and oxygenation by CMR facilitates direct monitoring of regional myocardial ischemia and provides a valuable tool for better understanding microvascular pathophysiology. These

  1. Higher levels of cardiovascular fitness are associated with better executive function and prefrontal oxygenation in younger and older women

    Directory of Open Access Journals (Sweden)

    Olivier eDupuy

    2015-02-01

    Full Text Available Aim: Many studies have suggested that physical exercise training improves cognition and more selectively executive functions. There is a growing interest to clarify the neurophysiological mechanisms that underlie this effect. The aim of the current study was to evaluate the neurophysiological changes in cerebral oxygenation associated with physical fitness level and executive functions. Method: In this study, 22 younger and 36 older women underwent a maximal graded continuous test (i.e., O2max in order to classifyassign them into a fitness group (higher vs. lower fit. All participants completed neuropsychological paper and pencil testing and a computerized Stroop task (which contained executive and non-executive conditions in which the change in pPrefrontal cortex oxygenation change was evaluated in all participants with a near infrared spectroscopy (NIRS. system during a computerized Stroop task (which contains executive and non-executive conditions. Results: Our findings revealed a Fitness x Condition interaction (p < .05 such that higher fit women scored better on measures of executive functions than lower fit women. In comparison to lower fit women, higher fit women had faster reaction times in the switching (executiveExecutive condition of the computerized Stroop task. No significant effect was observed ion the non-executive condition of the test and no interactions were found with age. In measures of cerebral oxygenation (ΔHbT and ΔHbO2, we found a main effect of fitness on cerebral oxygenation during the Stroop task such that only high fit women demonstrated a significant increase in the right inferior frontal gyrus. Discussion/Conclusion:Higher fit individuals who demonstrate better cardiorespiratory functions (as measured by O2max show faster reaction times and greater cerebral oxygenation in the right inferior frontal gyrus than women with lower fitness levels. The lack of interaction with age, suggests that good

  2. Cerebral blood flow and oxygen metabolism in patients with Parkinson's disease

    International Nuclear Information System (INIS)

    Kitamura, Shin; Ujike, Takashi; Kuroki, Soemu; Sakamoto, Shizuki; Soeda, Toshiyuki; Terashi, Akiro; Iio, Masaaki.

    1988-01-01

    The purpose of this study was to determine functional changes in the cerebral cortex and basal ganglia in Parkinson's disease (PD). Cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO 2 ) were determined using 0-15 positron emission tomography in 10 PD patients and five age-matched healthy volunteers. There was a tendency among PD patients towards a decreased CBF and CMRO 2 in the cerebral cortex and basal ganglia. These values were significantly lower in the frontal cortex in the PD group than the control group. There was no difference in OEF between the groups. A more decreased cerebral oxygen metabolism was observed in patients staged as severer on the scale of Hoehn and Yahr. There was no correlation between cerebral oxygen metabolism and tremor, rigidity, or bradykinesis. A decreased cerebral oxygen metabolism was associated with mental disorders, such as depression, hallucination, and dementia. These results may provide an important clue for the understanding of mesocortical dopaminergic pathway and the relationship between PD and dementia. (N.K.)

  3. Cerebral blood flow and oxygen metabolism in patients with Parkinson's disease

    Energy Technology Data Exchange (ETDEWEB)

    Kitamura, Shin; Ujike, Takashi; Kuroki, Soemu; Sakamoto, Shizuki; Soeda, Toshiyuki; Terashi, Akiro; Iio, Masaaki

    1988-10-01

    The purpose of this study was to determine functional changes in the cerebral cortex and basal ganglia in Parkinson's disease (PD). Cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO/sub 2/) were determined using 0-15 positron emission tomography in 10 PD patients and five age-matched healthy volunteers. There was a tendency among PD patients towards a decreased CBF and CMRO/sub 2/ in the cerebral cortex and basal ganglia. These values were significantly lower in the frontal cortex in the PD group than the control group. There was no difference in OEF between the groups. A more decreased cerebral oxygen metabolism was observed in patients staged as severer on the scale of Hoehn and Yahr. There was no correlation between cerebral oxygen metabolism and tremor, rigidity, or bradykinesis. A decreased cerebral oxygen metabolism was associated with mental disorders, such as depression, hallucination, and dementia. These results may provide an important clue for the understanding of mesocortical dopaminergic pathway and the relationship between PD and dementia. (N.K.).

  4. Photoacoustic measurements of red blood cell oxygen saturation in blood bags in situ

    Science.gov (United States)

    Pinto, Ruben N.; Bagga, Karan; Douplik, Alexandre; Acker, Jason P.; Kolios, Michael C.

    2017-03-01

    Red blood cell (RBC) transfusion is a critical component of the health care services. RBCs are stored in blood bags in hypothermic temperatures for a maximum of 6 weeks post donation. During this in vitro storage period, RBCs have been documented to undergo changes in structure and function due to mechanical and biochemical stress. Currently, there are no assessment methods that monitor the quality of RBCs within blood bags stored for transfusion. Conventional assessment methods require the extraction of samples, consequently voiding the sterility of the blood bags and potentially rendering them unfit for transfusions. It is hypothesized that photoacoustic (PA) technology can provide a rapid and non-invasive indication of RBC quality. In this study, a novel PA setup was developed for the acquisition of oxygen saturation (SO2) of two blood bags in situ. These measurements were taken throughout the lifespan of the blood bags (42 days) and compared against the clinical gold standard method of the blood gas analyzer (BGA). SO2 values of the blood bags increased monotonically throughout the storage period. A strong correlation between PA SO2 and BGA SO2 was found, however, PA values were on average 3.5% lower. Both techniques found the bags to increase by an SO2 of approximately 20%, and measured very similar rates of SO2 change. Future work will be focused on determining the cause of discrepancy between SO2 values acquired from PA versus BGA, as well as establishing links between the measured SO2 increase and other changes in RBC in situ.

  5. Depiction of blood vessels by x-ray phase contrast

    Energy Technology Data Exchange (ETDEWEB)

    Momose, Atsushi [School of Engineering, University of Tokyo, Tokyo (Japan); Takeda, Tohoru; Itai, Yuji [Institute of Clinical Medicine, University of Tsukuba, Tsukuba, Ibaraki (Japan)

    2001-04-01

    Blood vessels in livers of a mouse and a rat were depicted by phase-contrast x-ray imaging with an x-ray interferometer without using contrast agents. X-ray interference patterns were converted to image mapping x-ray phase shift caused by the livers using the technique of phase-shifting x-ray interferometry. The arteries and veins to and from the livers were tied before excision in order to prevent blood from flowing out of the liver. The x-ray phase shift caused by blood was substantially different from that caused by other soft sues, and consequently trees of blood vessels were revealed in the images. Vessels of diameter smaller than 0.1 mm were detected. This result suggests new possibilities for investigating vascular systems. (author)

  6. Blood transfusion in preterm infants improves intestinal tissue oxygenation without alteration in blood flow.

    Science.gov (United States)

    Banerjee, J; Leung, T S; Aladangady, N

    2016-11-01

    The objective of the study was to investigate the splanchnic blood flow velocity and oximetry response to blood transfusion in preterm infants according to postnatal age. Preterm infants receiving blood transfusion were recruited to three groups: 1-7 (group 1; n = 20), 8-28 (group 2; n = 21) and ≥29 days of life (group 3; n = 18). Superior mesenteric artery (SMA) peak systolic (PSV) and diastolic velocities were measured 30-60 min pre- and post-transfusion using Doppler ultrasound scan. Splanchnic tissue haemoglobin index (sTHI), tissue oxygenation index (sTOI) and fractional tissue oxygen extraction (sFTOE) were measured from 15-20 min before to post-transfusion using near-infrared spectroscopy. The mean pretransfusion Hb in group 1, 2 and 3 was 11, 10 and 9 g/dl, respectively. The mean (SD) pretransfusion SMA PSV in group 1, 2 and 3 was 0·63 (0·32), 0·81 (0·33) and 0·97 (0·40) m/s, respectively, and this did not change significantly following transfusion. The mean (SD) pretransfusion sTOI in group 1, 2 and 3 was 36·7 (19·3), 44·6 (10·4) and 41·3 (10·4)%, respectively. The sTHI and sTOI increased (P transfusion in all groups. On multivariate analysis, changes in SMA PSV and sTOI following blood transfusion were not associated with PDA, feeding, pretransfusion Hb and mean blood pressure. Pretransfusion baseline splanchnic tissue oximetry and blood flow velocity varied with postnatal age. Blood transfusion improved intestinal tissue oxygenation without altering mesenteric blood flow velocity irrespective of postnatal ages. © 2016 International Society of Blood Transfusion.

  7. The influence of contrast media on kidney function in patients with stable coronary artery disease.

    Science.gov (United States)

    Reuter, Simon Bertram; Harutyunyan, Marina; Mygind, Naja Dam; Jørgensen, Erik; Kastrup, Jens

    2014-08-01

    To investigate the incidence of contrast media-induced nephropathy (CIN) in patients with stable coronary artery disease (CAD) referred for elective coronary intervention following hydration routines. The reversibility of CIN was followed in a 6 month-period. A total of 447 patients referred for elective coronary intervention due to suspected CAD were included. Blood samples were collected before and 24 h after intervention and medical records were obtained. Patients had no drinking fluid restrictions and were routinely treated with a 1000 ml saline infusion. All patients were invited to a 6-month examination and collection of blood samples. A total of 19 patients (4.3%) developed CIN. CIN patients had a pre-investigation higher estimated glomerular filtration rate (eGRF), lower level of kidney failure and lower creatinine level than non-CIN patients. Kidney function was not normalized in CIN patients 6 months after the intervention. Two patients still met the definition of CIN. With no restriction in fluid intake and supplementary infusion of saline, only a few patients with stable CAD developed early indications of CIN during elective coronary interventions. Kidney function and the amount of contrast media used was not a predictor of CIN development. The induced CIN was not completely normalized in a 6-month follow-up period.

  8. A theoretical model for oxygen transport in skeletal muscle under conditions of high oxygen demand.

    Science.gov (United States)

    McGuire, B J; Secomb, T W

    2001-11-01

    Oxygen transport from capillaries to exercising skeletal muscle is studied by use of a Krogh-type cylinder model. The goal is to predict oxygen consumption under conditions of high demand, on the basis of a consideration of transport processes occurring at the microvascular level. Effects of the decline in oxygen content of blood flowing along capillaries, intravascular resistance to oxygen diffusion, and myoglobin-facilitated diffusion are included. Parameter values are based on human skeletal muscle. The dependence of oxygen consumption on oxygen demand, perfusion, and capillary density are examined. When demand is moderate, the tissue is well oxygenated and consumption is slightly less than demand. When demand is high, capillary oxygen content declines rapidly with axial distance and radial oxygen transport is limited by diffusion resistance within the capillary and the tissue. Under these conditions, much of the tissue is hypoxic, consumption is substantially less than demand, and consumption is strongly dependent on capillary density. Predicted consumption rates are comparable with experimentally observed maximal rates of oxygen consumption.

  9. Diagnosis of Popliteal Venous Entrapment Syndrome by Magnetic Resonance Imaging Using Blood-Pool Contrast Agents

    International Nuclear Information System (INIS)

    Beitzke, Dietrich; Wolf, Florian; Juelg, Gregor; Lammer, Johannes; Loewe, Christian

    2011-01-01

    Popliteal vascular entrapment syndrome is caused by aberrations or hypertrophy of the gastrocnemius muscles, which compress the neurovascular structures of the popliteal fossa, leading to symptoms of vascular and degeneration as well as aneurysm formation. Imaging of popliteal vascular entrapment may be performed with ultrasound, magnetic resonance imaging (MRI), computed tomography angiography, and conventional angiography. The use of blood-pool contrast agents in MRI when popliteal vascular entrapment is suspected offers the possibility to perform vascular imaging with first-pass magnetic resonance angiographic, high-resolution, steady-state imaging and allows functional tests all within one examination with a single dose of contrast agent. We present imaging findings in a case of symptomatic popliteal vein entrapment diagnosed by the use of blood pool contrast-enhanced MRI.

  10. Modifiers of hemoglobin/oxygen affinity as sensitizers of tumors to radiation

    International Nuclear Information System (INIS)

    Hirst, D.G.; Wood, P.J.

    1987-01-01

    A powerful mechanism in the control of oxygen delivery to tissues is the allosteric modification of hemoglobin. Increased or decreased release of oxygen can be achieved by altering the affinity of hemoglobin for oxygen. Several studies have shown that tumor radiosensitivity is dependent on this relationship. The authors studied affinity changes produced in two distinctly different ways. Tumor bearing mice were given isovolemic exchange blood transfusions with the blood from donor mice which had been exposed to abnormal oxygen tensions, leading to increased or slightly decreased levels of 2,3-diphosphoglycerate (2,3 DPG) in their blood. When the recipient mice were irradiated, those receiving the blood with higher 2,3 DPG levels showed greater tumor sensitivity to radiation. An alternative strategy is the use of drugs which directly alter hemoglobin/oxygen affinity. The authors studied three antihyperlipoproteinemia drugs, all of which have produced markedly reduced affinities in vivo. Preliminary data indicate that the radiosensitization produced by at least one of these compounds is less than would have been expected from the 2,3 DPG experiments

  11. High-resolution structural and functional assessments of cerebral microvasculature using 3D Gas ΔR2*-mMRA.

    Science.gov (United States)

    Huang, Chien-Hsiang; Chen, Chiao-Chi V; Siow, Tiing-Yee; Hsu, Sheng-Hsiou S; Hsu, Yi-Hua; Jaw, Fu-Shan; Chang, Chen

    2013-01-01

    The ability to evaluate the cerebral microvascular structure and function is crucial for investigating pathological processes in brain disorders. Previous angiographic methods based on blood oxygen level-dependent (BOLD) contrast offer appropriate visualization of the cerebral vasculature, but these methods remain to be optimized in order to extract more comprehensive information. This study aimed to integrate the advantages of BOLD MRI in both structural and functional vascular assessments. The BOLD contrast was manipulated by a carbogen challenge, and signal changes in gradient-echo images were computed to generate ΔR2* maps. Simultaneously, a functional index representing the regional cerebral blood volume was derived by normalizing the ΔR2* values of a given region to those of vein-filled voxels of the sinus. This method is named 3D gas ΔR2*-mMRA (microscopic MRA). The advantages of using 3D gas ΔR2*-mMRA to observe the microvasculature include the ability to distinguish air-tissue interfaces, a high vessel-to-tissue contrast, and not being affected by damage to the blood-brain barrier. A stroke model was used to demonstrate the ability of 3D gas ΔR2*-mMRA to provide information about poststroke revascularization at 3 days after reperfusion. However, this technique has some limitations that cannot be overcome and hence should be considered when it is applied, such as magnifying vessel sizes and predominantly revealing venous vessels.

  12. An Introduction to Normalization and Calibration Methods in Functional MRI

    Science.gov (United States)

    Liu, Thomas T.; Glover, Gary H.; Mueller, Bryon A.; Greve, Douglas N.; Brown, Gregory G.

    2013-01-01

    In functional magnetic resonance imaging (fMRI), the blood oxygenation level dependent (BOLD) signal is often interpreted as a measure of neural activity. However, because the BOLD signal reflects the complex interplay of neural, vascular, and metabolic processes, such an interpretation is not always valid. There is growing evidence that changes…

  13. Plasma lactate and stress hormones in common carp (Cyprinus carpio) and rainbow trout (Oncorhynchus mykiss) during stepwise decreasing oxygen levels

    NARCIS (Netherlands)

    Vianen, GJ; Van den Thillart, GEEJM; Van Kampen, M; Van Heel, TI; Steffens, AB

    By measuring the lactate response it is possible to determine whether a teleost is able to adapt to a certain oxygen level. It is hypothesized that recovery will occur at oxygen levels above the critical oxygen level (PO2)(crit) reflected by a transient lactate increase. In contrast, continuous

  14. Autoregressive moving average (ARMA) model applied to quantification of cerebral blood flow using dynamic susceptibility contrast-enhanced magnetic resonance imaging

    International Nuclear Information System (INIS)

    Murase, Kenya; Yamazaki, Youichi; Shinohara, Masaaki

    2003-01-01

    The purpose of this study was to investigate the feasibility of the autoregressive moving average (ARMA) model for quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in comparison with deconvolution analysis based on singular value decomposition (DA-SVD). Using computer simulations, we generated a time-dependent concentration of the contrast agent in the volume of interest (VOI) from the arterial input function (AIF) modeled as a gamma-variate function under various CBFs, cerebral blood volumes and signal-to-noise ratios (SNRs) for three different types of residue function (exponential, triangular, and box-shaped). We also considered the effects of delay and dispersion in AIF. The ARMA model and DA-SVD were used to estimate CBF values from the simulated concentration-time curves in the VOI and AIFs, and the estimated values were compared with the assumed values. We found that the CBF value estimated by the ARMA model was more sensitive to the SNR and the delay in AIF than that obtained by DA-SVD. Although the ARMA model considerably overestimated CBF at low SNRs, it estimated the CBF more accurately than did DA-SVD at high SNRs for the exponential or triangular residue function. We believe this study will contribute to an understanding of the usefulness and limitations of the ARMA model when applied to quantification of CBF with DSC-MRI. (author)

  15. Effects of Different Exercise Intensities with Isoenergetic Expenditures on C-Reactive Protein and Blood Lipid Levels

    Science.gov (United States)

    Tsao, Te Hung; Yang, Chang Bin; Hsu, Chin Hsing

    2012-01-01

    We investigated the effects of different exercise intensities on C-reactive protein (CRP), and whether changes in CRP levels correlated with blood lipid levels. Ten men exercised at 25%, 65%, and 85% of their maximum oxygen consumption rates. Participants' blood was analyzed for CRP and blood lipid levels before and after the exercise sessions.…

  16. Effect of blood transfusion on intestinal blood flow and oxygenation in extremely preterm infants during first week of life.

    Science.gov (United States)

    Banerjee, Jayanta; Leung, Terence S; Aladangady, Narendra

    2016-04-01

    Extremely preterm infants receive frequent blood transfusions in the first week of life. The aim of this study was to measure the effect of blood transfusion on intestinal blood flow and oxygenation during the first week of life in extremely preterm infants. Superior mesenteric artery (SMA) peak systolic velocity (PSV) and diastolic velocities were measured 30 to 60 minutes before and after transfusion. Splanchnic tissue hemoglobin index (sTHI), splanchnic tissue oxygenation index (sTOI), and splanchnic fractional tissue oxygen extraction (sFTOE) were measured continuously from 15 to 20 minutes before to after transfusion along with vital variables. Twenty infants were studied (median gestational age, 26 weeks). Ten infants were partially fed (15-68 mL/kg/day). Heart rate and SaO2 remained unaltered; blood pressure increased significantly (p transfusion. Mean SMA PSV (p = 0.63) and diastolic velocity (p = 0.65) remained unaltered. Mean pretransfusion SMA PSV was similar in partially fed (0.78 m/sec) compared to unfed infants (0.52 m/sec; p = 0.06) and the response to transfusion was not dissimilar. There was a significant increase in sTHI (mean difference, 32.3%; p transfusion. There was no significant difference in sTHI or sTOI between fed and unfed infants and their response to transfusion. Blood transfusion increased blood pressure and intestinal tissue oxygenation but did not alter blood flow velocities. Partial feeding had no impact on intestinal blood flow and tissue oxygenation changes. © 2015 AABB.

  17. Oxygen partial pressure dependence of electrical conductivity in γ'-Bi2MoO6

    International Nuclear Information System (INIS)

    Vera, C.M.C.; Aragon, R.

    2008-01-01

    The electrical conductivity of γ'-Bi 2 MoO 6 was surveyed between 450 and 750 deg. C as a function of oxygen partial pressure, in the range 0.01-1 atm. A -1/6 power law dependence, consistent with a Frenkel defect model of doubly ionized oxygen vacancies and interstitials, is evidence for an n-type semiconductive component, with an optical band gap of 2.9 eV. The absence of this dependence is used to map the onset of dominant ionic conduction. - Graphical abstract: Temporal dependence of electrical conductivity at 500 deg. C for γ'-Bi 2 MoO 6 at controlled partial pressures of oxygen

  18. Validation of Perfusion Quantification with 3D Gradient Echo Dynamic Contrast-Enhanced Magnetic Resonance Imaging Using a Blood Pool Contrast Agent in Skeletal Swine Muscle.

    Directory of Open Access Journals (Sweden)

    Stefan Hindel

    Full Text Available The purpose of our study was to validate perfusion quantification in a low-perfused tissue by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI with shared k-space sampling using a blood pool contrast agent. Perfusion measurements were performed in a total of seven female pigs. An ultrasonic Doppler probe was attached to the right femoral artery to determine total flow in the hind leg musculature. The femoral artery was catheterized for continuous local administration of adenosine to increase blood flow up to four times the baseline level. Three different stable perfusion levels were induced. The MR protocol included a 3D gradient-echo sequence with a temporal resolution of approximately 1.5 seconds. Before each dynamic sequence, static MR images were acquired with flip angles of 5°, 10°, 20°, and 30°. Both static and dynamic images were used to generate relaxation rate and baseline magnetization maps with a flip angle method. 0.1 mL/kg body weight of blood pool contrast medium was injected via a central venous catheter at a flow rate of 5 mL/s. The right hind leg was segmented in 3D into medial, cranial, lateral, and pelvic thigh muscles, lower leg, bones, skin, and fat. The arterial input function (AIF was measured in the aorta. Perfusion of the different anatomic regions was calculated using a one- and a two-compartment model with delay- and dispersion-corrected AIFs. The F-test for model comparison was used to decide whether to use the results of the one- or two-compartment model fit. Total flow was calculated by integrating volume-weighted perfusion values over the whole measured region. The resulting values of delay, dispersion, blood volume, mean transit time, and flow were all in physiologically and physically reasonable ranges. In 107 of 160 ROIs, the blood signal was separated, using a two-compartment model, into a capillary and an arteriolar signal contribution, decided by the F-test. Overall flow in hind leg muscles

  19. Levels-of-processing effect on frontotemporal function in schizophrenia during word encoding and recognition.

    Science.gov (United States)

    Ragland, J Daniel; Gur, Ruben C; Valdez, Jeffrey N; Loughead, James; Elliott, Mark; Kohler, Christian; Kanes, Stephen; Siegel, Steven J; Moelter, Stephen T; Gur, Raquel E

    2005-10-01

    Patients with schizophrenia improve episodic memory accuracy when given organizational strategies through levels-of-processing paradigms. This study tested if improvement is accompanied by normalized frontotemporal function. Event-related blood-oxygen-level-dependent functional magnetic resonance imaging (fMRI) was used to measure activation during shallow (perceptual) and deep (semantic) word encoding and recognition in 14 patients with schizophrenia and 14 healthy comparison subjects. Despite slower and less accurate overall word classification, the patients showed normal levels-of-processing effects, with faster and more accurate recognition of deeply processed words. These effects were accompanied by left ventrolateral prefrontal activation during encoding in both groups, although the thalamus, hippocampus, and lingual gyrus were overactivated in the patients. During word recognition, the patients showed overactivation in the left frontal pole and had a less robust right prefrontal response. Evidence of normal levels-of-processing effects and left prefrontal activation suggests that patients with schizophrenia can form and maintain semantic representations when they are provided with organizational cues and can improve their word encoding and retrieval. Areas of overactivation suggest residual inefficiencies. Nevertheless, the effect of teaching organizational strategies on episodic memory and brain function is a worthwhile topic for future interventional studies.

  20. Oxygen concentration inside a functioning photosynthetic cell.

    Science.gov (United States)

    Kihara, Shigeharu; Hartzler, Daniel A; Savikhin, Sergei

    2014-05-06

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic photosynthetic bacteria in solitary form could have evolved ∼2.8 billion years ago without special mechanisms to protect them against reactive oxygen species. These mechanisms instead could have been developed during the following ∼500 million years while the oxygen level in the Earth's atmosphere was slowly rising. Excess oxygen concentrations within individual cells of the apomorphic cyanobacteria Synechocystis and Synechococcus are 0.064 and 0.25 μM, respectively. These numbers suggest that intramembrane and intracellular proteins in isolated oxygenic photosynthetic cells are not subjected to excessively high oxygen levels. The situation is different for closely packed colonies of photosynthetic cells. Calculations show that the excess concentration within colonies that are ∼40 μm or larger in diameter can be comparable to the oxygen concentration in air-saturated water, suggesting that species forming colonies require protection against reactive oxygen species even in the absence of oxygen in the surrounding atmosphere. Copyright © 2014 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  1. Red blood cell transfusions and tissue oxygenation in anemic hematology outpatients.

    Science.gov (United States)

    Yuruk, Koray; Bartels, Sebastiaan A; Milstein, Dan M J; Bezemer, Rick; Biemond, Bart J; Ince, Can

    2012-03-01

    There is little clinical evidence that red blood cell (RBC) transfusions improve oxygen availability at the microcirculatory level. We tested the hypotheses that anemia in chronically anemic patients with relatively healthy microcirculation would be associated with low tissue hemoglobin (Hb) and tissue oxygenation levels and that these conditions would be improved after RBC transfusions. Near-infrared spectroscopy (NIRS) was used to determine tissue oxygen saturation (StO(2)) and tissue Hb index (THI; an index of the amount of Hb in the NIRS measurement volume) in the thenar eminence and sublingual tissue before and 30 minutes after RBC transfusions in 20 chronically anemic hematology outpatients. Data are presented as median (25%-75%). The patients received three (two to three) bags of RBCs in saline-adenine-glucose-mannitol with an age of 21 (7-21) days, which was infused intravenously at the rate of 0.7 bag/hr. RBC transfusions significantly increased hematocrit level from 26% (24%-28%) to 32% (30%-34%; p viscosity from 3.4 (3.1-3.5) mPa/sec to 4.2 (4.0-4.5) mPa/sec (p < 0.0001), thenar StO(2) from 81% (80%-84%) to 86% (81%-89%; p = 0.002), thenar THI from 11.2 (9.3-13.3) AU to 13.7 (9.7-15.3) AU (p = 0.024), sublingual StO(2) from 86% (81%-89%) to 91% (86%-92%; p < 0.0001), and sublingual THI from 15.2 (13.0-17.4) AU to 17.2 (13.5-19.7) AU (p = 0.040). Although anemia in chronically anemic hematology outpatients was not associated with low StO(2) and THI levels, RBC transfusions were successful in improving these variables. © 2011 American Association of Blood Banks.

  2. Oxygen Dependent Biocatalytic Processes

    DEFF Research Database (Denmark)

    Pedersen, Asbjørn Toftgaard

    Enzyme catalysts have the potential to improve both the process economics and the environ-mental profile of many oxidation reactions especially in the fine- and specialty-chemical industry, due to their exquisite ability to perform stereo-, regio- and chemo-selective oxida-tions at ambient...... to aldehydes and ketones, oxyfunctionalization of C-H bonds, and epoxidation of C-C double bonds. Although oxygen dependent biocatalysis offers many possibilities, there are numerous chal-lenges to be overcome before an enzyme can be implemented in an industrial process. These challenges requires the combined...... far below their potential maximum catalytic rate at industrially relevant oxygen concentrations. Detailed knowledge of the en-zyme kinetics are therefore required in order to determine the best operating conditions and design oxygen supply to minimize processing costs. This is enabled...

  3. Estimating the arterial input function from dynamic contrast-enhanced MRI data with compensation for flow enhancement (II): Applications in spine diagnostics and assessment of crohn's disease

    NARCIS (Netherlands)

    van Schie, Jeroen J. N.; Lavini, Cristina; van Vliet, Lucas J.; Kramer, Gem; Pieters-van den Bos, Indra; Marcus, J. T.; Stoker, Jaap; Vos, Frans M.

    2017-01-01

    Pharmacokinetic (PK) models can describe microvascular density and integrity. An essential component of PK models is the arterial input function (AIF) representing the time-dependent concentration of contrast agent (CA) in the blood plasma supplied to a tissue. To evaluate a novel method for

  4. Detection of haemoglobins with abnormal oxygen affinity by single blood gas analysis and 2,3-diphosphoglycerate measurement.

    Science.gov (United States)

    Guerrini, G; Morabito, A; Samaja, M

    2000-10-01

    The aim is to determine if a single measurement of blood 2,3-diphosphoglycerate combined with gas analysis (pH, PCO2, PO2 and saturation) can identify the cause of an altered blood-oxygen affinity: the presence of an abnormal haemoglobin or a red cell disorder. The population (n=94) was divided into healthy controls (A, n=14), carriers of red cell disorders (B, n=72) and carriers of high oxygen affinity haemoglobins (C, n=8). Those variables were measured both in samples equilibrated at selected PCO2 and PO2 and in venous blood. In the univariable approach applied to equilibrated samples, we correctly identified C subjects in 93.6% or 96.8% of the cases depending on the selected variable, the standard P50 (PO2 at which 50% of haemoglobin is oxygenated) or a composite variable calculated from the above measurements. After introducing the haemoglobin concentration as a further discriminating variable, the A and B subjects were correctly identified in 91.9% or 94.2% of the cases, respectively. These figures become 93.0% or 86.1%, and 93.7% or 94.9% of the cases when using direct readings from venous blood, thereby avoiding the blood equilibration step. This test is feasible also in blood samples stored at 4 degrees C for 48 h, or at room temperature for 8 h.

  5. Quantitative measurement of total cerebral blood flow using 2D phase-contrast MRI and doppler ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Keum Soo; Choi, Sun Seob; Lee, Young Il [Dong-A Univ., College of Medicine, Busan (Korea, Republic of)

    2001-12-01

    To compare of quantitative measurement of the total cerebral blood flow using two-dimensional phase-contrast MR imaging and Doppler ultrasound. In 16 volunteers (mean age, 26 years; mean body weight, 66 kg) without abnormal medical histories, two-dimensional phase-contrast MR imaging was performed at the level of the C2-3 inter vertebral disc for flow measurement of the internal carotid arteries and the vertebral arteries. Volume flow measurements using Doppler ultrasound were also performed at the internal carotid arteries 2cm above the carotid bifurcation, and at the vertebral arteries at the level of the upper pole of the thyroid gland. Flows in the four vessels measured by the two methods were compared using Wilcoxon's correlation analysis and the median score. Total cerebral blood flows were calculated by summing these four vessel flows, and mean values for the 16 volunteers were calculated. Cerebral blood flows measured by 2-D phase-contrast MR imaging and Doppler ultrasounds were 233 and 239 ml/min in the right internal carotid artery, 250 and 248 ml/min in the left internal carotid artery, 62 and 56 ml/min in the right vertebral artery, and 83 and 68 ml/min in the left vertebral artery. Correlation coefficients of the blood flows determined by the two methods were 0.48, 0.54, 0.49, and 0.62 in each vessel, while total cerebral blood flows were 628{+-}68 (range, 517 to 779) ml/min and 612{+-}79 (range, 482 to 804)ml/min, respectively. Total cerebral blood flow was easily measured using 2-D phase-contrast MR imaging and Doppler ultrasound, and the two noninvasive methods can therefore be used clinically for the measurement of total cerebral blood flow.

  6. Trial on MR portal blood flow measurement with phase contrast technique

    International Nuclear Information System (INIS)

    Tsunoda, Masatoshi; Kimoto, Shin; Togami, Izumi

    1991-01-01

    Portal blood flow measurement is considered to be important for the analysis of hemodynamics in various liver diseases. The Doppler ultrasound method has been used extensively during the past several years for measuring portal blood flow, as a non-invasive method. However, the Doppler ultrasound technique do not allow the portal blood flow to be measured in cases of obesity, with much intestinal gas, and so on. In this study, we attempted to measure the blood flow in the main trunk of portal vein as an application of MR phase contrast technique to the abdominal region. In the flow phantom study, the flow volumes and the velocities measured by phase contrast technique showed a close correlation with those measured by electromagnetic flowmeter. In the clinical study with 10 healthy volunteers, various values of portal blood flow were obtained. Mean portal blood flow could be measured within the measuring time (about 8 minutes) under natural breathing conditions. Phase contrast technique is considered to be useful for the non-invasive measurement of portal blood flow. (author)

  7. Effects of blood lead and cadmium levels on the functioning of children with behaviour disorders in the family environment.

    Science.gov (United States)

    Szkup-Jabłońska, Małgorzata; Karakiewicz, Beata; Grochans, Elżbieta; Jurczak, Anna; Nowak-Starz, Grażyna; Rotter, Iwona; Prokopowicz, Adam

    2012-01-01

    The developing brain of a child is extremely prone to damage resulting from exposure to harmful environmental factors, e.g. heavy metals. Intoxication of children's organisms with lead and cadmium affects their intellectual development. Even a relatively small amount of this metal in children's blood can lead to developmental dysfunctions. The aim of this study was to analyse the correlation between blood lead and cadmium levels in children with behaviour disorders and their functioning in the home. This survey-based study was conducted among 78 families with children diagnosed as having behaviour disorders. It was performed using the ADHD-Rating Scale-IV. To determine lead and cadmium levels the laboratory procedure was based on Stoppler and Brandt's method. The mean blood lead level was 19.71 µg/l and the mean blood cadmium level was 0.215 µg/l. Higher blood lead levels in children correlates positively with incidences of hyperactive and impulsive behaviour in the home, as assessed by parents (p=0.048). Statistically significant effects of cadmium on children's behaviour were not noticed. The effect of lead on the developing organism of a child has such behavioural consequences as attention disorders, hyperactivity and impulsive behaviour which, in turn, may interfere with children's functioning in the home. A negative effect of cadmium on the functioning of children with behaviour disorders in the home was not proved.

  8. Influence of Partial Pressure of Oxygen in Blood Samples on Measurement Performance in Glucose-Oxidase-Based Systems for Self-Monitoring of Blood Glucose

    Science.gov (United States)

    Baumstark, Annette; Schmid, Christina; Pleus, Stefan; Haug, Cornelia; Freckmann, Guido

    2013-01-01

    Background Partial pressure of oxygen (pO2) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO2 values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not. Methods Aliquots of 20 venous samples were adjusted to the following pO2 values: pO2 ~70 mmHg, which is considered to be similar to pO2 in capillary blood samples, and the mean BG result at pO2 pO2 pO2 ≥150 mmHg. For both pO2 levels, relative differences of all tested GOx systems were significant (p pO2 values pO2 variations lead to clinically relevant BG measurement deviations in GOx systems, even in GOx systems that are not labeled as being oxygen sensitive. PMID:24351177

  9. Positron emission tomography in cerebrovascular disease: The relationship between regional cerebral blood flow, blood volume and oxygen metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Herold, S.

    1985-03-01

    Positron emission tomography in cerebrovascular disease has demonstrated the importance of the relationship between regional cerebral blood flow and the cerebral metabolic activity. In acute stroke it has been found that within the first hours after the onset of symptoms cerebral blood flow in the affected area is more depressed than cerebral oxygen utilisation. This relative preservation of oxygen utilisation results from an increase in the oxygen extraction ratio far above its normal value. However, the oxygen extraction fraction subsequently falls in the following days indicating the transition from a situation of possibly reversible ischaemia to irreversible infarction. In patients with carotid occlusive disease an increase in the oxygen extraction ratio has been observed only in very few cases. It has been shown, however, that at an earlier stage the relationship between CBF and CBV (as CBF/CBV-ratio) provides a sensitive measure of diminished perfusion pressure which could be helpful for the selection of patients for EC-IC bypass surgery. In patients with sickle cell anaemia it has been found that oxygen delivery to the brain is maintained by an increase in cerebral blood flow, whereas the oxygen extraction ratio is not increased despite the presence of a low oxygen affinity haemoglobin. Preliminary observations in classical migraine suggest an ischaemic situation during the attack.

  10. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Gang; Lou, Yaxian; Pan, Zhiying; Liu, Ya [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China); Nanjing University of Aeronautics and Astronautics, College of Aivil Aviation, Nanjing, Jiangsu (China); Wen, Jiqiu; Li, Xue; Zhang, Zhe [Medical School of Nanjing University, National Clinical Research Center of Kidney Diseases, Jinling Hospital, Nanjing, Jiangsu (China); Lu, Hanzhang [University of Texas Southwestern Medical Center, Advanced Imaging Research Center, Dallas, TX (United States); Liu, Wei [Siemens Shenzhen Magnetic Resonance Ltd., Shenzhen, Guangdong (China); Liu, Hui [Siemens MR NEA Collaboration, Siemens Ltd., Shanghai (China); Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming [Medical School of Nanjing University, Department of Medical Imaging, Jinling Hospital, Nanjing, Jiangsu (China)

    2016-06-15

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO{sub 2} was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min{sup -1} 100 g{sup -1}, P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO{sub 2} (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O{sub 2} min{sup -1} 100 g{sup -1}, P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO{sub 2}. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO{sub 2}. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO{sub 2}. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. (orig.)

  11. [Effect of hemodilution with 10% hydroxyethyl starch solution (MW 200,000/9.5) on the flow properties of blood, arterial blood gases and conjunctival oxygen partial pressure in patients with cerebral infarct].

    Science.gov (United States)

    Staedt, U; Hütt, M; Herrmann, B; Seufzer, U; Leweling, H

    1989-06-01

    Hemorheological parameters, arterial blood gases and conjunctival oxygen tension were measured in 15 patients with acute ischemic stroke and compared with values obtained in an age matched reference group. Since the conjunctival capillary bed is perfused by the ophthalmic artery, it reflects the oxygen delivery to the areas supplied by the internal carotid artery. Measurements of conjunctival oxygen tension are simple and safe. Patients with acute ischemic stroke showed a lowered conjunctival oxygen tension; this holds true especially to the ipsilateral side, i.e. the side where the attack occurred, and to a lesser extent to the other side. By contrast, the ratio of arterial/conjunctival pO2 was disturbed only on the ipsilateral side. Furthermore, these patients had pathologically elevated values for red cell aggregation, whole blood and plasma viscosity. After infusing 500 ml 10% middle-molecular-weight hydroxyethyl starch (10% HAES-steril) and phlebotomy (250 ml) blood fluidity was normalized, although the hematokrit was only slightly reduced. Arterial pO2 improved slightly while pCO2 remained unchanged. Conjunctival oxygen tension improved by 30% on the ipsilateral and by 10% on the contralateral side, the ipsilateral values always remaining significantly lower. The ratio conjunctival/arterial pO2 raised only on the ipsilateral side where it was below the reference range before hemodilution. In addition to the well known improvement of blood fluidity and augmentation of cerebral blood flow following hemodilution in patients with acute ischemic stroke, there seems to be an increase in oxygen supply in the territories of both internal carotid arteries, especially on the ipsilateral side as indicated by the values of conjunctival oxygen tension and the ratio of conjunctival to arterial pO2.

  12. Effect of hypoxia on cerebral blood flow regulation during rest and exercise : role of cerebral oxygen delivery on performance

    OpenAIRE

    Fan, J.-L.

    2014-01-01

    Adequate supply of oxygen to the brain is critical for maintaining normal brain function. Severe hypoxia, such as that experienced during high altitude ascent, presents a unique challenge to brain oxygen (O2) supply. During high-intensity exercise, hyperventilation-induced hypocapnia leads to cerebral vasoconstriction, followed by reductions in cerebral blood flow (CBF), oxygen delivery (DO2), and tissue oxygenation. This reduced O2 supply to the brain could potentially account for the reduce...

  13. Vascular Function and Regulation of Blood Flow in Resting and Contracting Skeletal Muscle

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin

    importance. The present work provides new insight in to vasodilator interactions important for exercise hyperemia and sheds light on mechanisms important for vascular function and regulation of skeletal muscle blood flow in essential hypertension (high blood pressure) and aging and identifies mechanisms......The precise matching of blood flow, oxygen delivery and metabolism is essential as it ensures that any increase in muscle work is precisely matched by increases in oxygen delivery. Therefore, understanding the control mechanisms of skeletal muscle blood flow regulation is of great biological...... in the regulation of exercise hyperemia. Furthermore, blood flow to contracting leg skeletal muscles is reduced both in essential hypertension and with aging. The potential difference in vasoactive system(s) responsible for the reduction in blood flow in the two conditions is in agreement with the suggestion...

  14. Caffeine and cognition in functional magnetic resonance imaging.

    Science.gov (United States)

    Koppelstaetter, Florian; Poeppel, Thorsten D; Siedentopf, Christian M; Ischebeck, Anja; Kolbitsch, Christian; Mottaghy, Felix M; Felber, Stephan R; Jaschke, Werner R; Krause, Bernd J

    2010-01-01

    Caffeine has been consumed since ancient times due to its beneficial effects on attention, psychomotor function, and memory. Caffeine exerts its action mainly through an antagonism of cerebral adenosine receptors, although there are important secondary effects on other neurotransmitter systems. Recently, functional MRI (fMRI) entered the field of neuropharmacology to explore the intracerebral sites and mechanisms of action of pharmacological agents. However, as caffeine possesses vasoconstrictive properties it may interfere with the mechanisms underlying the functional contrast in fMRI. Yet, only a limited number of studies dealt with the effect of caffeine on measures in fMRI. Even fewer neuroimaging studies examined the effects that caffeine exerts on cognition: Portas and colleagues used fMRI in an attentional task under different levels of arousal (sleep deprivation or caffeine administration), concluding that the thalamus is involved in mediating the interaction of attention and arousal. Bendlin and colleagues found caffeine to stabilize the extent of neuronal activation in repetitive word stem completion, counteracting the general task practice effect. Recently, Koppelstaetter and colleagues assessed the effect of caffeine on verbal working memory demonstrating a modulatory effect of caffeine on brain regions (medial frontopolar and anterior cingulate cortex) that have been associated with attentional and executive functions. This review surveys and discusses neuroimaging findings on 1) how caffeine affects the contrast underlying fMRI techniques, particularly the blood oxygen level dependent contrast (BOLD fMRI), and 2) how caffeine operates on neuronal activity underlying cognition, to understand the effect of caffeine on behavior and its neurobiological underpinnings.

  15. [Healthy lifestyle formation and lower dependence on atmosphere oxygen in working].

    Science.gov (United States)

    Usti'yantsev, S L

    2016-01-01

    Studies covered 38 males in laboratory and 81 males in industrial conditions of 13 metallurgic enterprises and revealed some reliable phenomena caused by dry voluntary apnea of 10-60 seconds. At muscular rest and during physical exertion, evidences are that voluntary apnea forms transitory hypercapnic portion of blood in pulmonary arterial flow. First finding is that this portion in other blood behaves as an anabolic wave carrying increased concentration of low-molecular CO2 material and releasing additional (wave, according to authors) O2 from its depot in the body. This oxygen, in conditions of increased blood pressure due to apnea, is used for synthesis of additional ATP. These phenomena characterize formation and development a new beneficial physiologic system in workers--a functional system of motivation to healthy lifestyle.

  16. The effects of arterial carbon dioxide partial pressure and sevoflurane on capillary venous cerebral blood flow and oxygen saturation during craniotomy.

    Science.gov (United States)

    Klein, Klaus Ulrich; Glaser, Martin; Reisch, Robert; Tresch, Achim; Werner, Christian; Engelhard, Kristin

    2009-07-01

    Intraoperative routine monitoring of cerebral blood flow and oxygenation remains a technological challenge. Using the physiological principle of carbon dioxide reactivity of cerebral vasculature, we investigated a recently developed neuromonitoring device (oxygen-to-see, O2C device) for simultaneous measurements of regional cerebral blood flow (rvCBF), blood flow velocity (rvVelo), oxygen saturation (srvO2), and hemoglobin amount (rvHb) at the capillary venous level in patients subjected to craniotomy. Twenty-six neurosurgical patients were randomly assigned to anesthesia with 1.4% or 2.0% sevoflurane end-tidal concentration. After craniotomy, a fiberoptic probe was applied on a macroscopically healthy surface of cerebral tissue next to the site of surgery. Simultaneous measurements in 2 and 8 mm cerebral depth were performed in each patient during lower (35 mm Hg) and higher (45 mm Hg) levels (random order) of arterial carbon dioxide partial pressure (PaCO2). The principle of these measurements relies on the combination of laser-Doppler flowmetry (rvCBF, rvVelo) and photo-spectrometry (srvO2, rvHb). Linear models were fitted to test changes of end points (rvCBF, rvVelo, srvO2, rvHb) in response to lower and higher levels of PaCO2, 1.4% and 2.0% sevoflurane end-tidal concentration, and 2 and 8 mm cerebral depth. RvCBF and rvVelo were elevated by PaCO2 independent of sevoflurane concentration in 2 and 8 mm depth of cerebral tissue (P oxygen was decreased by elevated PaCO2. Unchanged levels of rvHb signify that there was no blood loss during measurements. Data suggest that the device allows detection of local changes in blood flow and oxygen saturation in response to different PaCO2 levels in predominant venous cerebral microvessels.

  17. Optoacoustic technique for noninvasive monitoring of blood oxygenation: a feasibility study

    Science.gov (United States)

    Esenaliev, Rinat O.; Larina, Irina V.; Larin, Kirill V.; Deyo, Donald J.; Motamedi, Massoud; Prough, Donald S.

    2002-08-01

    Replacement of invasive monitoring of cerebral venous oxygenation with noninvasive techniques offers great promise in the management of life-threatening neurologic illnesses including traumatic brain injury. We developed and built an optoacoustic system to noninvasively monitor cerebral venous oxygenation; the system includes a nanosecond Nd:YAG laser and a specially designed optoacoustic probe. We tested the system in vitro in sheep blood with experimentally varied oxygenation. Our results demonstrated that (1) the amplitude and temporal profile of the optoacoustic waves increase with blood oxygenation in the range from 24% to 92%, (2) optoacoustic signals can be detected despite optical and acoustic attenuation by thick bone, and (3) the system is capable of real-time and continuous measurements. These results suggest that the optoacoustic technique is technically feasible for continuous, noninvasive monitoring of cerebral venous oxygenation.

  18. The air we breathe: three vital respiratory gases and the red blood cell: oxygen, nitric oxide, and carbon dioxide.

    Science.gov (United States)

    Dzik, Walter H

    2011-04-01

    Three vital respiratory gases-oxygen (O(2)), nitric oxide (NO), and carbon dioxide (CO(2))-intersect at the level of the human red blood cell (RBC). In addition to hemoglobin (Hb)'s central role in O(2) transport, interaction of Hb with the Band 3 metabolon balances RBC energy flow. 2,3-Diphosphoglycerate enhances O(2) transport across the placenta and plays an important role in regulating RBC plasticity. NO is a key mediator of hypoxic vasodilation, but the precise role of RBC Hb remains controversial. In addition to established theories that depend on RBC uptake, delivery, and discharge of NO or its metabolites, an alternative hypothesis based on RBC permeability is suggested. NO depletion by free Hb may account for several clinical features seen during intravascular hemolysis or during deliberate infusion of Hb solutions used as RBC substitutes. CO(2) released by tissues triggers oxygen release through a series of well-coordinated reactions centered on the Band 3 metabolon. While RBC carbonic anhydrase and the Band 3 anion exchanger are central to this process, there is surprisingly little research on the kinetics of CO(2) clearance by transfusion. The three RBC gases are directly related to the three principal gases of Earth's atmosphere. Human fossil fuel consumption dumps 90 million metric tons of carbon into the atmosphere annually. Increasing CO(2) levels are linked to global warming, melting Arctic ice, rising sea levels, and climate instability. Just as individual cells depend on balance of the three vital gases, so too will their balance determine survival of life on Earth. © 2011 American Association of Blood Banks.

  19. Comparison of the OxyMask and Venturi mask in the delivery of supplemental oxygen: Pilot study in oxygen-dependent patients

    Science.gov (United States)

    Beecroft, Jaime M; Hanly, Patrick J

    2006-01-01

    BACKGROUND: The OxyMask (Southmedic Inc, Canada) is a new face mask for oxygen delivery that uses a small ‘diffuser’ to concentrate and direct oxygen toward the mouth and nose. The authors hypothesized that this unique design would enable the OxyMask to deliver oxygen more efficiently than a Venturi mask (Hudson RCI, USA) in patients with chronic hypoxemia. METHODS: Oxygen-dependent patients with chronic, stable respiratory disease were recruited to compare the OxyMask and Venturi mask in a randomized, single-blind, cross-over design. Baseline blood oxygen saturation (SaO2) was established breathing room air, followed in a random order by supplemental oxygen through the OxyMask or Venturi mask. Oxygen delivery was titrated to maintain SaO2 4% to 5% and 8% to 9% above baseline for two separate 30 min periods of stable breathing. Oxygen flow rate, partial pressure of inspired and expired oxygen (PO2) and carbon dioxide (PCO2), minute ventilation, heart rate, nasal and oral breathing, SaO2 and transcutaneous PCO2 were collected continuously. The study was repeated following alterations to the OxyMask design, which improved clearance of carbon dioxide. RESULTS: Thirteen patients, aged 28 to 79 years, were studied initially using the original OxyMask. Oxygen flow rate was lower, inspired PO2 was higher and expired PO2 was lower while using the OxyMask. Minute ventilation and inspired and expired PCO2 were significantly higher while using the OxyMask, whereas transcutaneous PCO2, heart rate and the ratio of nasal to oral breathing did not change significantly throughout the study. Following modification of the OxyMask, 13 additional patients, aged 18 to 79 years, were studied using the same protocol. The modified OxyMask provided a higher inspired PO2 at a lower flow rate, without evidence of carbon dioxide retention. CONCLUSIONS: Oxygen is delivered safely and more efficiently by the OxyMask than by the Venturi mask in stable oxygen-dependent patients. PMID:16896425

  20. Oxygen therapy - infants

    Science.gov (United States)

    ... breathe increased amounts of oxygen to get normal levels of oxygen in their blood. Oxygen therapy provides babies with the extra oxygen. Information Oxygen is a gas that the cells in your body need to work properly. The ...

  1. Imaging tools to study pharmacology: functional MRI on small rodents

    OpenAIRE

    Elisabeth eJonckers; Disha eShah; Julie eHamaide; Marleen eVerhoye; Annemie eVan Der Linden

    2015-01-01

    Functional Magnetic Resonance Imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sensory stimu...

  2. Respiratory properties of blood and hemoglobin solutions from the piranha

    DEFF Research Database (Denmark)

    Wood, S.C.; Weber, Roy E.; Powers, D.

    1979-01-01

    1. Respiratory properties of piranha blood are distinguished from those of other fish primarily by the high CO2 buffering capacity (?HCO3/-?pH= 19.6mmol/l for oxygenated blood and 39.1 mmol/l for deoxygenated blood). 2. The concentration of nucleoside triphosphates (NTP) and the half-saturation t......) lowered the oxygen affinity of purified hemoglobin solutions, accounting for the size-dependent correlation ofP50 and NTP concentration in whole blood. 5. While similar in concentration in red cells, GTP is more potent than ATP as an allosteric modifier of hemoglobin function....

  3. Cerebral blood flow and oxygen metabolism after subarachnoid hemorrhage

    International Nuclear Information System (INIS)

    Ito, Hidemichi; Sakurai, Takashi; Hayashi, Tatsuo; Hashimoto, Takuo

    2004-01-01

    The mechanism of reduction of cerebral circulation in the early phase of aneurysmal subarachnoid hemorrhage (SAH) has not yet been clarified. Previous studies have variously indicated that cerebral blood flow (CBF) reduction may be due to cerebral vasospasm, an elevation in intracranial pressure (ICP), constriction of intraparenchymal arterioles, or metabolic reduction. The aim of this study is to investigate the relationship between cerebral circulation and oxygen metabolism. In 36 patients with aneurysmal SAH, the values of mean cerebral blood flow (mCBF), cerebral metabolic rate of oxygen (GMRO 2 ) and oxygen extraction fraction (OEF) were measured by using single photon emission computed tomography (SPECT) with arterial blood drawing and oxygen saturation of internal jugular bulb blood (SjO 2 ) in the acute stage (1-3 days after onset) and the spasm stage (7-10 days after onset). The patients in our study were selected by using the following criteria: no history of cerebrovascular or cardiopulmonary diseases; under the age of 70; the ruptured aneurysm was treated by clipping or coil embolization within 72 hours after onset; no symptoms of cerebral vasospasm; no signs of cerebral ischemic change on CT scans. These patients were divided into 2 groups according to the World Federation of Neurological Surgeons (WFNS) grading classification; the mild group (Grades I and II) consisted of 27 cases and the severe group (Grade IV) consisted of 9 cases. We studied differences in mCBF CMRO 2 , and OEF between the mild group and severe group. In the mild group, mCBF, CMRO 2 , and OEF were significantly higher than in the severe group during both the acute and the spasm stage. Also mCBF showed a direct correlation with CMRO 2 . All the patients were kept under the following conditions: the bed was positioned so that the upper body was raised at an angle at 30 deg; blood pressure was maintained at 130-150 mmHg and PaCO 2 of arterial blood was maintained at 35-40 mmHg; ICP

  4. Effects of hypoglycemia on human brain activation measured with fMRI.

    Science.gov (United States)

    Anderson, Adam W; Heptulla, Rubina A; Driesen, Naomi; Flanagan, Daniel; Goldberg, Philip A; Jones, Timothy W; Rife, Fran; Sarofin, Hedy; Tamborlane, William; Sherwin, Robert; Gore, John C

    2006-07-01

    Functional magnetic resonance imaging (fMRI) was used to measure the effects of acute hypoglycemia caused by passive sensory stimulation on brain activation. Visual stimulation was used to generate blood-oxygen-level-dependent (BOLD) contrast, which was monitored during hyperinsulinemic hypoglycemic and euglycemic clamp studies. Hypoglycemia (50 +/- 1 mg glucose/dl) decreased the fMRI signal relative to euglycemia in 10 healthy human subjects: the fractional signal change was reduced by 28 +/- 12% (P variations in blood glucose levels may modulate BOLD signals in the healthy brain.

  5. Absolute quantification of regional renal blood flow in swine by dynamic contrast-enhanced magnetic resonance imaging using a blood pool contrast agent.

    Science.gov (United States)

    Lüdemann, Lutz; Nafz, Benno; Elsner, Franz; Grosse-Siestrup, Christian; Meissler, Michael; Kaufels, Nicola; Rehbein, Hagen; Persson, Pontus B; Michaely, Henrik J; Lengsfeld, Philipp; Voth, Matthias; Gutberlet, Matthias

    2009-03-01

    To evaluate for the first time in an animal model the possibility of absolute regional quantification of renal medullary and cortical perfusion by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) using a blood pool contrast agent. A total of 18 adult female pigs (age, 16-22 weeks; body weight, 45-65 kg; no dietary restrictions) were investigated by DCE-MRI. Absolute renal blood flow (RBF) measured by an ultrasound transit time flow probe around the renal vein was used as the standard of reference. An inflatable stainless cuff placed around the renal artery near its origin from the abdominal aorta was used to reduce RBF to 60%, 40%, and 20% of the baseline flow. The last measurement was performed with the cuff fully reopened. Absolute RBF values during these 4 perfusion states were compared with the results of DCE-MRI performed on a 1.5-T scanner with an 8-channel phased-array surface coil. All scans were acquired in breath-hold technique in the coronal plane using a field of view of 460 mm.Each dynamic scan commenced with a set of five 3D T1-weighted gradient echo sequences with different flip angles (alpha = 2 degrees, 5 degrees, 10 degrees, 20 degrees, 30 degrees): TE, 0.88 milliseconds; TR, 2.65 milliseconds; slice thickness, 8.8 mm for 4 slices; acquisition matrix, 128 x 128; and acquisitions, 4. These data served to calculate 3D intrinsic longitudinal relaxation rate maps (R10) and magnetization (M0). Immediately after these images, the dynamic 3D T1-weighted gradient echo images were acquired with the same parameters and a constant alpha = 30 degrees, half Fourier, 1 acquisition, 64 frames, a time interval of 1.65 seconds between each frame, and a total duration of 105.6. Three milliliters of an albumin-binding blood pool contrast agent (0.25 mmol/mL gadofosveset trisodium, Vasovist, Bayer Schering Pharma AG, Berlin, Germany) was injected at a rate of 3 mL/s. Perfusion was calculated using the arterial input function from the aorta, which was

  6. Serum Reactive Oxygen Metabolite Levels Predict Severe Exacerbations of Asthma

    Science.gov (United States)

    Nakamoto, Keitaro; Watanabe, Masato; Sada, Mitsuru; Inui, Toshiya; Nakamura, Masuo; Honda, Kojiro; Wada, Hiroo; Mikami, Yu; Matsuzaki, Hirotaka; Horie, Masafumi; Noguchi, Satoshi; Yamauchi, Yasuhiro; Koyama, Hikari; Kogane, Toshiyuki; Kohyama, Tadashi; Takizawa, Hajime

    2016-01-01

    Background and Purpose Bronchial asthma (BA) is a chronic airway disease characterized by airway hyperresponsiveness and remodeling, which are intimately linked to chronic airway inflammation. Reactive oxygen species (ROS) such as hydrogen peroxide are generated by inflammatory cells that are involved in the pathogenesis of BA. However, the role of ROS in the management of BA patients is not yet clear. We attempted to determine the role of ROS as a biomarker in the clinical setting of BA. Subjects and Methods We enrolled patients with BA from 2013 through 2015 and studied the degrees of asthma control, anti-asthma treatment, pulmonary function test results, fractional exhaled nitric oxide (FeNO), serum reactive oxygen metabolite (ROM) levels, and serum levels of interleukin (IL)-6 and IL-8. Results We recruited 110 patients with BA. Serum ROM levels correlated with white blood cell (WBC) count (rs = 0.273, p = 0.004), neutrophil count (rs = 0.235, p = 0.014), CRP (rs = 0.403, p < 0.001), and IL-6 (rs = 0.339, p < 0.001). Serum ROM levels and IL-8 and CRP levels negatively correlated with %FEV1 (rs = -0.240, p = 0.012, rs = -0.362, p < 0.001, rs = -0.197, p = 0.039, respectively). Serum ROM levels were significantly higher in patients who experienced severe exacerbation within 3 months than in patients who did not (339 [302–381] vs. 376 [352–414] CARR U, p < 0.025). Receiver-operating characteristics analysis showed that ROM levels correlated significantly with the occurrence of severe exacerbation (area under the curve: 0.699, 95% CI: 0.597–0.801, p = 0.025). Conclusions Serum levels of ROM were significantly associated with the degrees of airway obstruction, WBC counts, neutrophil counts, IL-6, and severe exacerbations. This biomarker may be useful in predicting severe exacerbations of BA. PMID:27776186

  7. Photoplethysmography for blood volumes and oxygenation changes during intermittent vascular occlusions.

    Science.gov (United States)

    Abay, T Y; Kyriacou, P A

    2018-06-01

    ] indicated significant changes for occlusion pressures exceeding 20 mmHg (p < 0.05) and correlation with tissue oxygenation changes measured by NIRS, while SpO[Formula: see text] had significant changes after 40 mmHg (p < 0.05). Relative changes in haemoglobin concentrations can be estimated from PPG signals and they showed a good level of accuracy in the detection of perfusion and oxygenation changes induced by different degrees of intermittent vascular occlusions. These results can open up to new applications of the PPG waveform in the detection of blood volumes and oxygenation changes.

  8. Attenuation of Morphine Physical Dependence and Blood Levels of Cortisol by Central and Systemic Administration of Ramelteon in Rat

    Directory of Open Access Journals (Sweden)

    Majid Motaghinejad

    2015-05-01

    Full Text Available Background: Chronic administration of morphine cause physical dependence but the exact mechanism of this phenomenon remains unclear. The aim of this study is the assessment of systemic and intracerebroventricular (icv administration of ramelteon (a melatonin receptor agonist on morphine physical dependence. Methods: 88 adult male rats were divided into 2 major groups, namely “systematic” and “central” administration of ramelteon. In the first category, systemic administration of ramelteon at various dosages (10, 20, and 40 mg/kg was assessed on dependent animals and withdrawal signs were compared with positive (received morphine and saline as systemic administration, negative control (saline and group under treatment by ramelteon (40 mg/kg groups. In the second category, central administration of ramelteon at various dosages (25, 50, or 100 μg, was assessed on dependent animals and withdrawal signs were compared with the positive control (received morphine and saline as icv and negative control (saline groups, and the group under treatment by ramelteon (50 μg/5 μl/rat. On the test day, all animals received naloxone (3 mg/kg and were observed for withdrawal signs. Total withdrawal score (TWS was also determined. Finally, to evaluate the stress level of dependent rats, blood cortisols were measured. Results: Central administration of ramelteon in all doses and systemic administration in high doses attenuate withdrawal syndrome in comparison with the dependent positive control group (P<0.05. Both central and systemic administrations of ramelteon can attenuate the blood cortisol level in comparison with the dependent positive control group (P<0.05. Conclusion: In conclusion, we found that central administration of ramelteon attenuated morphine withdrawal symptoms and cortisol level as a stress marker.

  9. Investigating tissue respiration and skin microhaemocirculation under adaptive changes and the synchronization of blood flow and oxygen saturation rhythms

    International Nuclear Information System (INIS)

    Dunaev, A V; Palmer, S G; Stewart, N A; Sokolovski, S G; Rafailov, E U; Sidorov, V V; Krupatkin, A I; Rafailov, I E

    2014-01-01

    Multi-functional laser non-invasive diagnostic systems allow the study of a number of microcirculatory parameters, including index of blood microcirculation (I m ) (by laser Doppler flowmetry, LDF) and oxygen saturation (S t O 2 ) of skin tissue (by tissue reflectance oximetry, TRO). This research aimed to use such a system to investigate the synchronization of microvascular blood flow and oxygen saturation rhythms under normal and adaptive change conditions. Studies were conducted on eight healthy volunteers of 21–49 years. These volunteers were observed between one and six months, totalling 422 basic tests (3 min each). Measurements were performed on the palmar surface of the right middle finger and the lower forearm's medial surface. Rhythmic oscillations of LDF and TRO were studied using wavelet analysis. Combined tissue oxygen consumption data for all volunteers during ‘adaptive changes’ increased relative to normal conditions with and without arteriovenous anastomoses. Data analysis revealed resonance and synchronized rhythms in microvascular blood flow and oxygen saturation as an adaptive change in myogenic oscillation (vasomotion) resulting from exercise and possibly psychoemotional stress. Synchronization of myogenic rhythms during adaptive changes may lead to increased oxygen consumption as a result of increased microvascular blood flow velocity. (paper)

  10. Optic nerve oxygenation

    DEFF Research Database (Denmark)

    Stefánsson, Einar; Pedersen, Daniella Bach; Jensen, Peter Koch

    2005-01-01

    The oxygen tension of the optic nerve is regulated by the intraocular pressure and systemic blood pressure, the resistance in the blood vessels and oxygen consumption of the tissue. The oxygen tension is autoregulated and moderate changes in intraocular pressure or blood pressure do not affect...... the optic nerve oxygen tension. If the intraocular pressure is increased above 40 mmHg or the ocular perfusion pressure decreased below 50 mmHg the autoregulation is overwhelmed and the optic nerve becomes hypoxic. A disturbance in oxidative metabolism in the cytochromes of the optic nerve can be seen...... at similar levels of perfusion pressure. The levels of perfusion pressure that lead to optic nerve hypoxia in the laboratory correspond remarkably well to the levels that increase the risk of glaucomatous optic nerve atrophy in human glaucoma patients. The risk for progressive optic nerve atrophy in human...

  11. Meal-induced changes in splanchnic blood flow and oxygen uptake in middle-aged healthy humans

    DEFF Research Database (Denmark)

    Madsen, Jan Lysgård; Søndergaard, SB; Møller, Søren

    2006-01-01

    OBJECTIVE: For decades, the determination of changes in splanchnic blood flow and oxygen uptake after a meal has been used in the management of patients with suspected chronic intestinal ischaemia. However, little is known about the normal meal-induced responses. The aim of the present study...... was therefore to measure the splanchnic blood flow and oxygen uptake before and after a standardized meal in a group of middle-aged normal volunteers. MATERIAL AND METHODS: Splanchnic blood flow and oxygen uptake were determined at baseline and after a 3600-kJ mixed meal in 8 healthy women (50-70 years) and 10...... healthy men (52-76 years). Splanchnic blood flow was measured during hepatic vein catheterization by indirect Fick principle with indocyanine green as the indicator. Splanchnic oxygen uptake was calculated from splanchnic blood flow and the arteriovenous oxygen difference. RESULTS: The meal induced...

  12. Determination of blood oxygenation in the brain by time-resolved reflectance spectroscopy: influence of the skin, skull, and meninges

    Science.gov (United States)

    Hielscher, Andreas H.; Liu, Hanli; Wang, Lihong; Tittel, Frank K.; Chance, Britton; Jacques, Steven L.

    1994-07-01

    Near infrared light has been used for the determination of blood oxygenation in the brain but little attention has been paid to the fact that the states of blood oxygenation in arteries, veins, and capillaries differ substantially. In this study, Monte Carlo simulations for a heterogeneous system were conducted, and near infrared time-resolved reflectance measurements were performed on a heterogeneous tissue phantom model. The model was made of a solid polyester resin, which simulates the tissue background. A network of tubes was distributed uniformly through the resin to simulate the blood vessels. The time-resolved reflectance spectra were taken with different absorbing solutions filled in the network. Based on the simulation and experimental results, we investigated the dependence of the absorption coefficient obtained from the heterogeneous system on the absorption of the actual absorbing solution filled in the tubes. We show that light absorption by the brain should result from the combination of blood and blood-free tissue background.

  13. Effect of 2,3-diphosphoglycerate on oxygen affinity of blood in sickle cell anemia

    Science.gov (United States)

    Charache, Samuel; Grisolia, Santiago; Fiedler, Adam J.; Hellegers, Andre E.

    1970-01-01

    Blood of patients with sickle cell anemia (SS) exhibits decreased affinity for oxygen, although the oxygen affinity of hemoglobin S is the same as that of hemoglobin A. SS red cells contain more 2,3-diphosphoglycerate (DPG) than normal erythrocytes. The oxygen affinity of hemolyzed red cells is decreased by added DPG, and hemolysates prepared from SS red cells do not differ from normal hemolysates in this regard. Reduction of oxygen affinity to the levels found in intact SS red cells required DPG concentrations in excess of those found in most SS patients. The same was true of oxygen affinity of patients with pyruvate kinase deficiency. Other organic phosphates, as well as inorganic ions, are known to alter the oxygen affinity of dilute solutions of hemoglobin. These substances, the state of aggregation of hemoglobin molecules, and cytoarchitectural factors probably play roles in determining oxygen affinity of both normal and SS red cells. PMID:5443181

  14. Field strength and dose dependence of contrast enhancement by gadolinium-based MR contrast agents

    International Nuclear Information System (INIS)

    Rinck, P.A.; Muller, R.N.

    1999-01-01

    The relaxivities r 1 and r 2 of magnetic resonance contrast agents and the T 1 relaxation time values of tissues are strongly field dependent. We present quantitative data and simulations of different gadolinium-based extracellular fluid contrast agents and the modulation of their contrast enhancement by the magnetic field to be able to answer the following questions: How are the dose and field dependences of their contrast enhancement? Is there an interrelationship between dose and field dependence? Should one increase or decrease doses at specific fields? Nuclear magnetic relaxation dispersion data were acquired for the following contrast agents: gadopentetate dimeglumine, gadoterate meglumine, gadodiamide injection, and gadoteridol injection, as well as for several normal and pathological human tissue samples. The magnetic field range stretched from 0.0002 to 4.7 T, including the entire clinical imaging range. The data acquired were then fitted with the appropriate theoretical models. The combination of the diamagnetic relaxation rates (R 1 = 1/T 1 and R 2 = 1/T 2 ) of tissues with the respective paramagnetic contributions of the contrast agents allowed the prediction of image contrast at any magnetic field. The results revealed a nearly identical field and dose-dependent increase of contrast enhancement induced by these contrast agents within a certain dose range. The target tissue concentration (TTC) was an important though nonlinear factor for enhancement. The currently recommended dose of 0.1 mmol/kg body weight seems to be a compromise close to the lower limits of diagnostically sufficient contrast enhancement for clinical imaging at all field strengths. At low field contrast enhancement might be insufficient. Adjustment of dose or concentration, or a new class of contrast agents with optimized relaxivity, would be a valuable contribution to a better diagnostic yield of contrast enhancement at all fields. (orig.)

  15. Low oxygen level increases proliferation and metabolic changes in bovine granulosa cells.

    Science.gov (United States)

    Shiratsuki, Shogo; Hara, Tomotaka; Munakata, Yasuhisa; Shirasuna, Koumei; Kuwayama, Takehito; Iwata, Hisataka

    2016-12-05

    The present study addresses molecular backgrounds underlying low oxygen induced metabolic changes and 1.2-fold change in bovine granulosa cell (GCs) proliferation. RNA-seq revealed that low oxygen (5%) upregulated genes associated with HIF-1 and glycolysis and downregulated genes associated with mitochondrial respiration than that in high oxygen level (21%). Low oxygen level induced high glycolytic activity and low mitochondrial function and biogenesis. Low oxygen level enhanced GC proliferation with high expression levels of HIF-1, VEGF, AKT, mTOR, and S6RP, whereas addition of anti-VEGF antibody decreased cellular proliferation with low phosphorylated AKT and mTOR expression levels. Low oxygen level reduced SIRT1, whereas activation of SIRT1 by resveratrol increased mitochondrial replication and decreased cellular proliferation with reduction of phosphorylated mTOR. These results suggest that low oxygen level stimulates the HIF1-VEGF-AKT-mTOR pathway and up-regulates glycolysis, which contributes to GC proliferation, and downregulation of SIRT1 contributes to hypoxia-associated reduction of mitochondria and cellular proliferation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  16. Activity-dependent increases in local oxygen consumption correlate with postsynaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Engelund

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO(2)) and cerebral blood flow (CBF). Activity-dependent rises in CMRO(2) fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca(2+) stimulate oxidative m...

  17. Association Between Exercise and Blood Glucose Levels In Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Eryna Laili Putri

    2017-02-01

    Full Text Available Diabetes Mellitus (DM is a chronic disease with high prevalence, associated with various debilitating complications and can decreases the quality of life in people with it. It is important for people with DM to doing exercise to control the stability of their blood glucose levels. The purpose of this study was to finding out the association between frequency, duration, and intensity of exercise with average blood glucose levels in people with DM. This was an observational study that used case control design. Data obtained from interview with 20 samples from case group and 20 samples from control group, that had been chosen with systematic random sampling technique. Dependent variable of this study was the average blood glucose levels and independents variables were frequency, duration, intensity, and the kind of exercise. This study used Chi Square test 3 × 2 contingency tables to finding out the association and risk of dependent variable with independent variables,. The results showed that exercise factors that associated to average blood glucose levels were duration of exercise (p = 0.022 and intensity of exercise (p = 0.021. The frequency of exercise does not associated to average blood glucose levels (p = 0.340. Diabetic patients who did not do any exercise have the risk of having uncontrolled blood glucose levels. The conclusion was duration and intensity of exercise related significantly to blood glucose levels. By doing exercise three times a week for 30 minutes or more can decreases the risk of uncontrolled blood glucose levels in people with DM. Keywords: Diabetes mellitus, exercise, average blood glucose levels

  18. Heating patterns during cancer heat therapy as a function of blood flow

    International Nuclear Information System (INIS)

    Mendecki, J.; Friedenthal, E.; Botstein, C.; Sterzer, F.; Paglione, R.W.

    1984-01-01

    Heating patterns as a function of regional blood flow were evaluated in healthy tissues with different vascular characteristics as well as in a variety of tumors submitted to microwave and RF-induced hyperthermia. Generally, faster heating and slower cooling was demonstrated for tumors. Definite correlation was found between the power needed to heat given tissue volume to a specific temperature and the ability of this tissue to dissipate heat via vascular flow. The measurements show that during the early phase of heating of tumors temperature rises slowly up to about 40 0 C. indicating good heat exchanges but that at this level rapid increase of temperature occurs for relatively small increments of power input. It is suggested that blood flow in malignant tissue remains competent and responsive to low grade heating, but that at higher temperature levels, in contrast to normal tissue, tumor blood flow rapidly decreases indicating compromised vascular system. Implication for treatment protocols are discussed

  19. Surfactant Protein D Levels in Umbilical Cord Blood and Capillary Blood of Premature Infants

    DEFF Research Database (Denmark)

    Dahl, Marianne; Holmskov, Uffe; Husby, Steffen

    2006-01-01

    of SP-D in capillary blood day 1 was 1,466 ng/mL (range 410-5,051 ng/mL), with lowest values in infants born with ROM and delivered vaginally. High SP-D levels in umbilical cord blood and capillary blood on day 1 were found to be more likely in infants in need for respiratory support or surfactant...... treatment and susceptibility to infections. We conclude that SP-D concentrations in umbilical cord blood and capillary blood in premature infants are twice as high as in mature infants and depend on several perinatal conditions. High SP-D levels in umbilical cord blood and capillary blood on day 1 were...... found to be related to increased risk of RDS and infections....

  20. Correlation of results obtained by in-vivo optical spectroscopy with measured blood oxygen saturation using a positive linear regression fit

    Science.gov (United States)

    McCormick, Patrick W.; Lewis, Gary D.; Dujovny, Manuel; Ausman, James I.; Stewart, Mick; Widman, Ronald A.

    1992-05-01

    Near infrared light generated by specialized instrumentation was passed through artificially oxygenated human blood during simultaneous sampling by a co-oximeter. Characteristic absorption spectra were analyzed to calculate the ratio of oxygenated to reduced hemoglobin. A positive linear regression fit between diffuse transmission oximetry and measured blood oxygenation over the range 23% to 99% (r2 equals .98, p signal was observed in the patient over time. The procedure was able to be performed clinically without difficulty; rSO2 values recorded continuously demonstrate the usefulness of the technique. Using the same instrumentation, arterial input and cerebral response functions, generated by IV tracer bolus, were deconvoluted to measure mean cerebral transit time. Date collected over time provided a sensitive index of changes in cerebral blood flow as a result of therapeutic maneuvers.

  1. Effects of exercise training on calf muscle oxygen extraction and blood flow in patients with peripheral artery disease.

    Science.gov (United States)

    Baker, Wesley B; Li, Zhe; Schenkel, Steven S; Chandra, Malavika; Busch, David R; Englund, Erin K; Schmitz, Kathryn H; Yodh, Arjun G; Floyd, Thomas F; Mohler, Emile R

    2017-12-01

    We employed near-infrared optical techniques, diffuse correlation spectroscopy (DCS), and frequency-domain near-infrared spectroscopy (FD-NIRS) to test the hypothesis that supervised exercise training increases skeletal muscle microvascular blood flow and oxygen extraction in patients with peripheral artery disease (PAD) who experience claudication. PAD patients ( n = 64) were randomly assigned to exercise and control groups. Patients in the exercise group received 3 mo of supervised exercise training. Calf muscle blood flow and oxygen extraction were optically monitored before, during, and after performance of a graded treadmill protocol at baseline and at 3 mo in both groups. Additionally, measurements of the ankle-brachial index (ABI) and peak walking time (PWT) to maximal claudication were made during each patient visit. Supervised exercise training was found to increase the maximal calf muscle blood flow and oxygen extraction levels during treadmill exercise by 29% (13%, 50%) and 8% (1%, 12%), respectively [ P group population were significantly higher than corresponding changes in the control group ( P training also increased PWT by 49% (18%, 101%) ( P = 0.01). However, within statistical error, the ABI, resting calf muscle blood flow and oxygen extraction, and the recovery half-time for hemoglobin\\myoglobin desaturation following cessation of maximal exercise were not altered by exercise training. The concurrent monitoring of both blood flow and oxygen extraction with the hybrid DCS/FD-NIRS instrument revealed enhanced muscle oxidative metabolism during physical activity from exercise training, which could be an underlying mechanism for the observed improvement in PWT. NEW & NOTEWORTHY We report on noninvasive optical measurements of skeletal muscle blood flow and oxygen extraction dynamics before/during/after treadmill exercise in peripheral artery disease patients who experience claudication. The measurements tracked the effects of a 3-mo supervised

  2. Hepatic blood perfusion estimated by dynamic contrast-enhanced computed tomography in pigs

    DEFF Research Database (Denmark)

    Winterdahl, Michael; Sørensen, Michael; Keiding, Inger Susanne

    2012-01-01

    The aim of this study was to determine whether dynamic contrast-enhanced computed tomography (DCE-CT) and the slope method can provide absolute measures of hepatic blood perfusion from the hepatic artery (HA) and portal vein (PV) at experimentally varied blood flow rates.......The aim of this study was to determine whether dynamic contrast-enhanced computed tomography (DCE-CT) and the slope method can provide absolute measures of hepatic blood perfusion from the hepatic artery (HA) and portal vein (PV) at experimentally varied blood flow rates....

  3. Effect Of Garlic Oil On Haematological Parameters, Blood Respiratory Functions And Serum Testosterone In Male Rats Exposed To An Electromagnetic Field

    International Nuclear Information System (INIS)

    EL-SHAFEY, A.A.; ALI, E.A.; MARZOOK, E.A.

    2009-01-01

    This study was conducted to investigate the biological effects of exposure to an electromagnetic field (EMF, 900 MHz) emitted from mobile base station antenna for 4 weeks on haematological parameters, respiratory function of blood (blood gases, acid-base status) and oxygen equilibrium curves beside the levels of serum testosterone and possible protective role of garlic oil (250 mg/kg b.w/day for 4 weeks) in male albino rats. The results revealed significant reductions in haemoglobin (Hb) contents, total leucocytes (WBC) count, mean corpuscular volume (MCV) and haematocrit value (Hct %) in rats exposed to EMF (GI). These reductions have been ameliorated by garlic oil treatment (GII). Significant increases in oxygen partial pressure (PO 2 ) were observed in arterial (a) and alveolar (A) blood. These increases were reduced by garlic oil treatment. The percent oxygen saturation (% O 2 sat) was significantly decreased in arterial while it was increased significantly in venous blood in both treated groups. There was a significant reduction in carbon dioxide partial pressure (PCO 2 ) in the arterial blood after exposure to EMF (GI) which was decreased by garlic oil treatment. Significant reductions were recorded in arterial blood pH, bicarbonate (HCO - 3 ), total carbon dioxide (TCO 2 ) and arterial and venous blood base excess (BE). These reductions were decreased by garlic oil treatment in GII. The blood oxygen equilibrium curves (OEC) of (GI) and (GII) were shifted to the right compared to that of control group with non-significant increases in P 50 . The level of serum testosterone was highly significantly decreased in GI. This reduction was decreased in garlic oil treated group (GII). It can be concluded that garlic oil has a protective role against the hazardous effects of EMF.

  4. Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease

    Science.gov (United States)

    Fernandes, Sheila Marques; Martins, Daniel Malisani; da Fonseca, Cassiane Dezoti; Watanabe, Mirian; Vattimo, Maria de Fátima Fernandes

    2016-01-01

    Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI. PMID:27034930

  5. Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease

    Directory of Open Access Journals (Sweden)

    Sheila Marques Fernandes

    2016-01-01

    Full Text Available Iodinated contrast (IC is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI. Chronic kidney disease (CKD and chronic hyperglycemia (CH are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH; Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulin clearance; urinary neutrophil gelatinase-associated lipocalin, NGAL and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulin clearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI.

  6. Atorvastatin affects negatively respiratory function of isolated endothelial mitochondria.

    Science.gov (United States)

    Broniarek, Izabela; Jarmuszkiewicz, Wieslawa

    2018-01-01

    The purpose of this research was to elucidate the direct effects of two popular blood cholesterol-lowering drugs used to treat cardiovascular diseases, atorvastatin and pravastatin, on respiratory function, membrane potential, and reactive oxygen species formation in mitochondria isolated from human umbilical vein endothelial cells (EA.hy926 cell line). Hydrophilic pravastatin did not significantly affect endothelial mitochondria function. In contrast, hydrophobic calcium-containing atorvastatin induced a loss of outer mitochondrial membrane integrity, an increase in hydrogen peroxide formation, and reductions in maximal (phosphorylating or uncoupled) respiratory rate, membrane potential and oxidative phosphorylation efficiency. The atorvastatin-induced changes indicate an impairment of mitochondrial function at the level of ATP synthesis and at the level of the respiratory chain, likely at complex I and complex III. The atorvastatin action on endothelial mitochondria was highly dependent on calcium ions and led to a disturbance in mitochondrial calcium homeostasis. Uptake of calcium ions included in atorvastatin molecule induced mitochondrial uncoupling that enhanced the inhibition of the mitochondrial respiratory chain by atorvastatin. Our results indicate that hydrophobic calcium-containing atorvastatin, widely used as anti-atherosclerotic agent, has a direct negative action on isolated endothelial mitochondria. Copyright © 2017. Published by Elsevier Inc.

  7. Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study.

    Science.gov (United States)

    Zheng, Gang; Wen, Jiqiu; Lu, Hanzhang; Lou, Yaxian; Pan, Zhiying; Liu, Wei; Liu, Hui; Li, Xue; Zhang, Zhe; Chen, Huijuan; Kong, Xiang; Luo, Song; Jiang, Xiaolu; Liu, Ya; Zhang, Zongjun; Zhang, Long Jiang; Lu, Guang Ming

    2016-06-01

    To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO2 was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 ± 12.5 vs. 63.8 ± 8.5 ml min(-1) 100 g(-1), P < 0.001), elevated OEF (47.2 ± 10.2 vs. 35.8 ± 5.4 %, P < 0.001), but unaffected CMRO2 (199.5 ± 36.4 vs. 193.8 ± 28.6 μmol O2 min(-1) 100 g(-1), P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO2. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO2. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO2. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. • Anaemic young adults with ESRD may afford higher CBF and OEF. • Anaemic young adults with ESRD maintain a normal CMRO 2 . • Cognitive function was still impaired in young ESRD adults. • The severity of cognitive dysfunction correlated with CBF and OEF changes.

  8. Oxygen-Dependent Cell-to-Cell Variability in the Output of the Escherichia coli Tor Phosphorelay.

    Science.gov (United States)

    Roggiani, Manuela; Goulian, Mark

    2015-06-15

    Escherichia coli senses and responds to trimethylamine-N-oxide (TMAO) in the environment through the TorT-TorS-TorR signal transduction system. The periplasmic protein TorT binds TMAO and stimulates the hybrid kinase TorS to phosphorylate the response regulator TorR through a phosphorelay. Phosphorylated TorR, in turn, activates transcription of the torCAD operon, which encodes the proteins required for anaerobic respiration via reduction of TMAO to trimethylamine. Interestingly, E. coli respires TMAO in both the presence and absence of oxygen, a behavior that is markedly different from the utilization of other alternative electron acceptors by this bacterium. Here we describe an unusual form of regulation by oxygen for this system. While the average level of torCAD transcription is the same for aerobic and anaerobic cultures containing TMAO, the behavior across the population of cells is strikingly different under the two growth conditions. Cellular levels of torCAD transcription in aerobic cultures are highly heterogeneous, in contrast to the relatively homogeneous distribution in anaerobic cultures. Thus, oxygen regulates the variance of the output but not the mean for the Tor system. We further show that this oxygen-dependent variability stems from the phosphorelay. Trimethylamine-N-oxide (TMAO) is utilized by numerous bacteria as an electron acceptor for anaerobic respiration. In E. coli, expression of the proteins required for TMAO respiration is tightly regulated by a signal transduction system that is activated by TMAO. Curiously, although oxygen is the energetically preferred electron acceptor, TMAO is respired even in the presence of oxygen. Here we describe an interesting and unexpected form of regulation for this system in which oxygen produces highly variable expression of the TMAO utilization proteins across a population of cells without affecting the mean expression of these proteins. To our knowledge, this is the first reported example of a stimulus

  9. Respiratory adaptations in carp blood. Influences of hypoxia, red cell organic phosphates, divalent cations and CO2 on hemoglobin-oxygen affinity

    DEFF Research Database (Denmark)

    Weber, Roy E.; Lykkeboe, G.

    1978-01-01

    This study concerns the adaptation of oxygen transporting function of carp blood to environment hypoxia, tracing the roles played by erythrocytic cofactors, inorganic cations, carbon dioxide and hemoglobin multiplicity. Carp acclimated to hypoxia ( 30 mmHg) display striking increases in blood oxy...

  10. Effects of aging on cerebral oxygenation during working-memory performance: a functional near-infrared spectroscopy study.

    Directory of Open Access Journals (Sweden)

    Anouk Vermeij

    Full Text Available Working memory is sensitive to aging-related decline. Evidence exists that aging is accompanied by a reorganization of the working-memory circuitry, but the underlying neurocognitive mechanisms are unclear. In this study, we examined aging-related changes in prefrontal activation during working-memory performance using functional Near-Infrared Spectroscopy (fNIRS, a noninvasive neuroimaging technique. Seventeen healthy young (21-32 years and 17 healthy older adults (64-81 years performed a verbal working-memory task (n-back. Oxygenated and deoxygenated hemoglobin concentration changes were registered by two fNIRS channels located over the left and right prefrontal cortex. Increased working-memory load resulted in worse performance compared to the control condition in older adults, but not in young participants. In both young and older adults, prefrontal activation increased with rising working-memory load. Young adults showed slight right-hemispheric dominance at low levels of working-memory load, while no hemispheric differences were apparent in older adults. Analysis of the time-activation curve during the high working-memory load condition revealed a continuous increase of the hemodynamic response in the young. In contrast to that, a quadratic pattern of activation was found in the older participants. Based on these results it could be hypothesized that young adults were better able to keep the prefrontal cortex recruited over a prolonged period of time. To conclude, already at low levels of working-memory load do older adults recruit both hemispheres, possibly in an attempt to compensate for the observed aging-related decline in performance. Also, our study shows that aging effects on the time course of the hemodynamic response must be taken into account in the interpretation of the results of neuroimaging studies that rely on blood oxygen levels, such as fMRI.

  11. The Effect of Disinfection on Viability and Function of Baboon Red Blood Cells and Platelets

    Science.gov (United States)

    1997-07-11

    blood cells was evaluated by their ability to transport oxygen as assessed by measurement of 2,3 diphosphoglycerate (DPG)14 and red blood cell p50,15...Blood collected from the bleeding time site (referred to as "shed blood") had a significantly reduced thromboxane A2 level . The ability of the...preserved or treated platelets to increase the shed blood thromboxane A2 level and reduce the 8; extended bleeding time is the measure of their

  12. The effects of exercise under hypoxia on cognitive function.

    Directory of Open Access Journals (Sweden)

    Soichi Ando

    Full Text Available Increasing evidence suggests that cognitive function improves during a single bout of moderate exercise. In contrast, exercise under hypoxia may compromise the availability of oxygen. Given that brain function and tissue integrity are dependent on a continuous and sufficient oxygen supply, exercise under hypoxia may impair cognitive function. However, it remains unclear how exercise under hypoxia affects cognitive function. The purpose of this study was to examine the effects of exercise under different levels of hypoxia on cognitive function. Twelve participants performed a cognitive task at rest and during exercise at various fractions of inspired oxygen (FIO2: 0.209, 0.18, and 0.15. Exercise intensity corresponded to 60% of peak oxygen uptake under normoxia. The participants performed a Go/No-Go task requiring executive control. Cognitive function was evaluated using the speed of response (reaction time and response accuracy. We monitored pulse oximetric saturation (SpO2 and cerebral oxygenation to assess oxygen availability. SpO2 and cerebral oxygenation progressively decreased during exercise as the FIO2 level decreased. Nevertheless, the reaction time in the Go-trial significantly decreased during moderate exercise. Hypoxia did not affect reaction time. Neither exercise nor difference in FIO2 level affected response accuracy. An additional experiment indicated that cognitive function was not altered without exercise. These results suggest that the improvement in cognitive function is attributable to exercise, and that hypoxia has no effects on cognitive function at least under the present experimental condition. Exercise-cognition interaction should be further investigated under various environmental and exercise conditions.

  13. Erythropoetin treatment can increase 2,3-diphosphoglycerate levels in red blood cells.

    Science.gov (United States)

    Birgegård, G; Sandhagen, B

    2001-01-01

    Some patients experience an improved well-being during treatment with recombinant human erythropoietin even with an unchanged Hb level. We have hypothesized that this may not be only a placebo effect. 2,3-diphosphoglycerate (2,3-DPG) in red blood cells increases in response to anaemia/hypoxia and causes a shift of the oxygen dissociation curve, allowing a more effective oxygen delivery. We have investigated red cell 2,3-DPG concentrations during erythropoietin treatment in healthy volunteers as a mediator of a possible physiological explanation. Thirteen healthy subjects with no iron deficiency were recruited and randomly assigned to a treatment group comprising five males and three females and a control group including three males and two females. The treatment group was treated with erythropoietin (Recormon), 20 IE/kg subcutaneously three times/week for 4 weeks. Blood samples were collected at each injection day and 10 days after the last injection and at corresponding times in the control group. B-Hb, red cell 2,3-DPG and P50 were measured by standard techniques and oxygen-releasing capacity was calculated. due to the sampling (26 ml each time, three times/week) the mean Hb level was lowered from 140.5 +/- 5.9 to 128.6 +/- 10.4 g/L in the control group whereas the erythropoietin treatment group maintained a mean Hb level of about 142 g/L (plevel curve as well as that for oxygen releasing capacity also differed significantly between the two groups (p levels. treatment with erythropoietin causes an increase in red cell 2,3-DPG levels.

  14. Performance evaluation of photoacoustic oximetry imaging systems using a dynamic blood flow phantom with tunable oxygen saturation

    Science.gov (United States)

    Vogt, William C.; Zhou, Xuewen; Andriani, Rudy; Wear, Keith A.; Garra, Brian S.; Pfefer, Joshua

    2018-02-01

    Photoacoustic Imaging (PAI) is an emerging technology with strong potential for broad clinical applications from breast cancer detection to cerebral monitoring due to its ability to compute maps of blood oxygen saturation (SO2) distribution in deep tissues using multispectral imaging. However, no well-validated consensus test methods currently exist for evaluating oximetry-specific performance characteristics of PAI devices. We have developed a phantombased flow system capable of rapid SO2 adjustment to serve as a test bed for elucidation of factors impacting SO2 measurement and quantitative characterization of device performance. The flow system is comprised of a peristaltic pump, membrane oxygenator, oxygen and nitrogen gas, and in-line oxygen, pH, and temperature sensors that enable real-time estimation of SO2 reference values. Bovine blood was delivered through breast-relevant tissue phantoms containing vessel-mimicking fluid channels, which were imaged using a custom multispectral PAI system. Blood was periodically drawn for SO2 measurement in a clinical-grade CO-oximeter. We used this flow phantom system to evaluate the impact of device parameters (e.g.,wavelength-dependent fluence corrections) and tissue parameters (e.g. fluid channel depth, blood SO2, spectral coloring artifacts) on oximetry measurement accuracy. Results elucidated key challenges in PAI oximetry and device design trade-offs, which subsequently allowed for optimization of system performance. This approach provides a robust benchtop test platform that can support PAI oximetry device optimization, performance validation, and clinical translation, and may inform future development of consensus test methods for performance assessment of photoacoustic oximetry imaging systems.

  15. Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

    Directory of Open Access Journals (Sweden)

    Farideh Sharifipour

    2013-01-01

    Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

  16. Gas exchange efficiency of an oxygenator with integrated pulsatile displacement blood pump for neonatal patients.

    Science.gov (United States)

    Schlanstein, Peter C; Borchardt, Ralf; Mager, Ilona; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Arens, Jutta

    2014-01-01

    Oxygenators have been used in neonatal extracorporeal membrane oxygenation (ECMO) since the 1970s. The need to develop a more effective oxygenator for this patient cohort exists due to their size and blood volume limitations. This study sought to validate the next design iteration of a novel oxygenator for neonatal ECMO with an integrated pulsatile displacement pump, thereby superseding an additional blood pump. Pulsating blood flow within the oxygenator is generated by synchronized active air flow expansion and contraction of integrated silicone pump tubes and hose pinching valves located at the oxygenator inlet and outlet. The current redesign improved upon previous prototypes by optimizing silicone pump tube distribution within the oxygenator fiber bundle; introduction of an oval shaped inner fiber bundle core, and housing; and a higher fiber packing density, all of which in combination reduced the priming volume by about 50% (50 to 27 mL and 41 to 20 mL, respectively). Gas exchange efficiency was tested for two new oxygenators manufactured with different fiber materials: one with coating and one with smaller pore size, both capable of long-term use (OXYPLUS® and CELGARD®). Results demonstrated that the oxygen transfer for both oxygenators was 5.3-24.7 mlO2/min for blood flow ranges of 100-500 mlblood/min. Carbon dioxide transfer for both oxygenators was 3.7-26.3 mlCO2/min for the same blood flow range. These preliminary results validated the oxygenator redesign by demonstrating an increase in packing density and thus in gas transfer, an increase in pumping capacity and a reduction in priming volume.

  17. Dietary Flavanols: A Review of Select Effects on Vascular Function, Blood Pressure, and Exercise Performance.

    Science.gov (United States)

    Al-Dashti, Yousef A; Holt, Roberta R; Stebbins, Charles L; Keen, Carl L; Hackman, Robert M

    2018-05-02

    An individual's diet affects numerous physiological functions and can play an important role in reducing the risk of cardiovascular disease. Epidemiological and clinical studies suggest that dietary flavanols can be an important modulator of vascular risk. Diets and plant extracts rich in flavanols have been reported to lower blood pressure, especially in prehypertensive and hypertensive individuals. Flavanols may act in part through signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxing and constricting factors. During exercise, flavanols have been reported to modulate metabolism and respiration (e.g., maximal oxygen uptake, O 2 cost of exercise, and energy expenditure), and reduce oxidative stress and inflammation, resulting in increased skeletal muscle efficiency and endurance capacity. Flavanol-induced reductions in blood pressure during exercise may decrease the work of the heart. Collectively, these effects suggest that flavanols can act as an ergogenic aid to help delay the onset of fatigue. More research is needed to better clarify the effects of flavanols on vascular function, blood pressure regulation, and exercise performance and establish safe and effective levels of intake. Flavanol-rich foods and food products can be useful components of a healthy diet and lifestyle program for those seeking to better control their blood pressure or to enhance their physical activity. Key teaching points • Epidemiological and clinical studies indicate that dietary flavanols can reduce the risk of vascular disease. • Diets and plant extracts rich in flavanols have been reported to lower blood pressure and improve exercise performance in humans. • Mechanisms by which flavanols may reduce blood pressure function include alterations in signaling pathways that affect vascular function, nitric oxide availability, and the release of endothelial-derived relaxation and constriction factors.

  18. Oxygen dissociation curves of whole blood from the Egyptian free ...

    African Journals Online (AJOL)

    Tadarida aegyptiaca (mean body mass 13.5 g) is a fast flying insectivorous bat that hunts in open areas for extended periods, covering extensive distances during its foraging bouts. Whole blood samples taken from the wing arteries were analysed for 2,3-diphosphoglyceric acid, oxygen affinity and pH. The mean oxygen ...

  19. Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

  20. Thyroid hormone stimulated glucose uptake in human mononuclear blood cells from normal persons and from patients with non-insulin-dependent diabetes mellitus

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L

    1989-01-01

    Thyroxine and T3 induced oxygen consumption and glucose uptake were studied in vitro in mononuclear blood cells isolated from patients with non-insulin-dependent diabetes mellitus (NIDDM) and from non-diabetic control persons. Cellular oxygen consumption and glucose uptake were promptly increased...

  1. BLOOD COMPATIBILITY OF 2 DIFFERENT TYPES OF MEMBRANE-OXYGENATOR DURING CARDIOPULMONARY BYPASS IN INFANTS

    NARCIS (Netherlands)

    GU, YJ; BOONSTRA, PW; AKKERMAN, C; MUNGROOP, H; TIGCHELAAR, [No Value; VANOEVEREN, W

    1994-01-01

    The contact of blood with the artificial extracorporeal circuit causes a systemic inflammatory response due to blood activation. In this study, we compared two different paediatric membrane oxygenators used for extracorporeal circulation: a hollow fibre membrane oxygenator (Dideco Masterflo D-701,

  2. Activity-dependent increases in local oxygen consumption correlate with post-synaptic currents in the mouse cerebellum in vivo

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Caesar, Kirsten; Thomsen, Kirsten Joan

    2011-01-01

    Evoked neural activity correlates strongly with rises in cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow. Activity-dependent rises in CMRO2 fluctuate with ATP turnover due to ion pumping. In vitro studies suggest that increases in cytosolic Ca2+ stimulate oxidative metabolism vi...

  3. The role of tissue oxygen tension in the control of local blood flow in the microcirculation of skeletal muscles

    DEFF Research Database (Denmark)

    Ngo, Thuc Anh

    2010-01-01

    In the microcirculation blood flow is highly regulated dependent on the metabolic activity of the tissues. Among several mechanisms, mechanisms involved in the coupling of changes in tissue oxygen tension due to changes in the metabolic activity of the tissue play an important role. In the systemic...... (inhibitor of KATP channels) in the superfusate abolished both vasodilatation and constriction to low and high oxygen superfusate, indicating that KATP channels are involved in both hypoxic vasodilatation and hyperoxic vasoconstriction. Red blood cells (RBCs) have been proposed to release ATP and...... as in the intact blood-perfused arteriole. This indicates that RBCs are not essential for hypoxic vasodilatation. In addition several potential pathways were evaluated. Application of DPCPX (inhibitor of adenosine A1 and A2 receptors) and L-NAME (inhibitor of NO-synthase) did not affect vasomotor responses to low...

  4. Optically measured microvascular blood flow contrast of malignant breast tumors.

    Directory of Open Access Journals (Sweden)

    Regine Choe

    Full Text Available Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS, a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92-2.63; tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94-2.66, and using normal tissue in the contralateral breast was 2.27 (1.90-2.70. Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography.

  5. Noninvasive MRI measurement of the absolute cerebral blood volume-cerebral blood flow relationship during visual stimulation in healthy humans.

    Science.gov (United States)

    Ciris, Pelin Aksit; Qiu, Maolin; Constable, R Todd

    2014-09-01

    The relationship between cerebral blood volume (CBV) and cerebral blood flow (CBF) underlies blood oxygenation level-dependent functional MRI signal. This study investigates the potential for improved characterization of the CBV-CBF relationship in humans, and examines sex effects as well as spatial variations in the CBV-CBF relationship. Healthy subjects were imaged noninvasively at rest and during visual stimulation, constituting the first MRI measurement of the absolute CBV-CBF relationship in humans with complete coverage of the functional areas of interest. CBV and CBF estimates were consistent with the literature, and their relationship varied both spatially and with sex. In a region of interest with stimulus-induced activation in CBV and CBF at a significance level of the P < 0.05, a power function fit resulted in CBV = 2.1 CBF(0.32) across all subjects, CBV = 0.8 CBF(0.51) in females and CBV = 4.4 CBF(0.15) in males. Exponents decreased in both sexes as ROIs were expanded to include less significantly activated regions. Consideration for potential sex-related differences, as well as regional variations under a range of physiological states, may reconcile some of the variation across literature and advance our understanding of the underlying cerebrovascular physiology. Copyright © 2013 Wiley Periodicals, Inc.

  6. High-affinity hemoglobin and blood oxygen saturation in diving emperor penguins.

    Science.gov (United States)

    Meir, Jessica U; Ponganis, Paul J

    2009-10-01

    The emperor penguin (Aptenodytes forsteri) thrives in the Antarctic underwater environment, diving to depths greater than 500 m and for durations longer than 23 min. To examine mechanisms underlying the exceptional diving ability of this species and further describe blood oxygen (O2) transport and depletion while diving, we characterized the O2-hemoglobin (Hb) dissociation curve of the emperor penguin in whole blood. This allowed us to (1) investigate the biochemical adaptation of Hb in this species, and (2) address blood O2 depletion during diving, by applying the dissociation curve to previously collected partial pressure of O2 (PO2) profiles to estimate in vivo Hb saturation (SO2) changes during dives. This investigation revealed enhanced Hb-O2 affinity (P50=28 mmHg, pH 7.5) in the emperor penguin, similar to high-altitude birds and other penguin species. This allows for increased O2 at low blood PO2 levels during diving and more complete depletion of the respiratory O2 store. SO2 profiles during diving demonstrated that arterial SO2 levels are maintained near 100% throughout much of the dive, not decreasing significantly until the final ascent phase. End-of-dive venous SO2 values were widely distributed and optimization of the venous blood O2 store resulted from arterialization and near complete depletion of venous blood O2 during longer dives. The estimated contribution of the blood O2 store to diving metabolic rate was low and highly variable. This pattern is due, in part, to the influx of O2 from the lungs into the blood during diving, and variable rates of tissue O2 uptake.

  7. Age- and Functional Status-Dependent Association Between Blood Pressure and Cognition

    DEFF Research Database (Denmark)

    Ogliari, Giulia; Sabayan, Behnam; Mari, Daniela

    2015-01-01

    OBJECTIVES: To evaluate whether the relationship between blood pressure (BP) measures and cognitive function is different according to age and functional status in older outpatients. DESIGN: Cross-sectional. SETTING: Outpatient hospital-based Milan Geriatrics 75+ Cohort Study. PARTICIPANTS......: Individuals aged 75 and older (N = 1,540). MEASUREMENTS: Blood pressure, Mini-Mental State Examination (MMSE), basic activities of daily living (ADLs), and instrumental activities of daily living (IADLs) were assessed. Associations between BP measures and MMSE score were first analyzed in the total population...... using linear regression models and were then further examined according to strata of age, ADLs, and IADLs. All analyses were adjusted for sociodemographic factors and presence of comorbidities. RESULTS: In the total population, higher systolic BP (SBP), diastolic BP (DBP), pulse pressure (PP), and mean...

  8. Cardiopulmonary function and oxygen delivery during total liquid ventilation.

    Science.gov (United States)

    Tsagogiorgas, Charalambos; Alb, Markus; Herrmann, Peter; Quintel, Michael; Meinhardt, Juergen P

    2011-10-01

    Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV. Copyright © 2011 Wiley-Liss, Inc.

  9. Functional morphology and patterns of blood flow in the heart of Python regius.

    Science.gov (United States)

    Starck, J Matthias

    2009-06-01

    Brightness-modulated ultrasonography, continuous-wave Doppler, and pulsed-wave Doppler-echocardiography were used to analyze the functional morphology of the undisturbed heart of ball pythons. In particular, the action of the muscular ridge and the atrio-ventricular valves are key features to understand how patterns of blood flow emerge from structures directing blood into the various chambers of the heart. A step-by-step image analysis of echocardiographs shows that during ventricular diastole, the atrio-ventricular valves block the interventricular canals so that blood from the right atrium first fills the cavum venosum, and blood from the left atrium fills the cavum arteriosum. During diastole, blood from the cavum venosum crosses the muscular ridge into the cavum pulmonale. During middle to late systole the muscular ridge closes, thus prohibiting further blood flow into the cavum pulmonale. At the same time, the atrio-ventricular valves open the interventricular canal and allow blood from the cavum arteriosum to flow into the cavum venosum. In the late phase of ventricular systole, all blood from the cavum pulmonale is pressed into the pulmonary trunk; all blood from the cavum venosum is pressed into both aortas. Quantitative measures of blood flow volume showed that resting snakes bypass the pulmonary circulation and shunt about twice the blood volume into the systemic circulation as into the pulmonary circulation. When digesting, the oxygen demand of snakes increased tremendously. This is associated with shunting more blood into the pulmonary circulation. The results of this study allow the presentation of a detailed functional model of the python heart. They are also the basis for a functional hypothesis of how shunting is achieved. Further, it was shown that shunting is an active regulation process in response to changing demands of the organism (here, oxygen demand). Finally, the results of this study support earlier reports about a dual pressure

  10. Evaluation of clot formation in blood-contrast agent mixture: experimental study on ionic/nonionic contrast agents and plastic/ glass syringes

    International Nuclear Information System (INIS)

    Shim, Hyung Jin; Lee, Jong Beum; Lee, Yong Chul; Lee, Kwan Seh; Kim, Kun Sang

    1991-01-01

    Recent introduction of low-osmolar nonionic contrast agents has allowed the performance of angiography with certain advantages such as reduced pain, reduced osmotic load and other potential advantages, over high osmolar ionic contrast agents. But the potential thrombogenic risk of nonionic contrast agent has been debate because of their weak anticoagulation effect. Several reports have recently documented the formation of thrombi in catheters and syringes containing nonionic contrast agent, and thromboembolic episodes have been noted during angiographic procedures. We have also been experienced blood clotting within blood mixed contrast agent syringe during angiography. Thus, we have studied with blood mixed ionic (Diatrizoate, Ioglicate) agents and nonionic (Iopamidol, Iopromide) agents, that used usually in our hospital, and saline in plastic and glass syringes. Each syringes were checked the clot formation on 10,30,60,90 minutes. Total 340 samples were obtained from 8 adults before angiography. Our data showed that nonionic contrast agents had significantly lesser anticoagulation effect than ionic contrast agents (ρ < 0.0001) on Chi-square test), both in plastic and glass syringes. And formation of clotting in glass syringes were significantly greater than that in plastic syringes (ρ < 0.0001). Thus meticulous technique is required to prevent thrombosis during angiographic procedure using nonionic contrast agents

  11. Cerebral blood flow and oxygen consumption during ethanol withdrawal in the rat.

    Science.gov (United States)

    Hemmingsen, R; Barry, D I; Hertz, M M; Klinken, L

    1979-09-14

    The ethanol withdrawal syndrome in man and animals is characterized by signs of CNS hyperactivity although a direct measurement of a physiological variable reflecting this CNS hyperactivity has never been performed in untreated man or in animals. We induced ethanol dependence in the rat by means of intragastric intubation with a 20% w/v ethanol solution, thus keeping the animals in a state of continuous severe intoxication for 3--4 days; during the subsequent state of withdrawal characterized by tremor, rigidity, stereotyped movements and general seizures a 25% increase in cerebral oxygen consumption (CMRO2) could be measured; this increase was not due to catecholamines originating from adrenal medulla as adrenomedullectomized animals showed a similar increase in CMRO2 (28%); the withdrawing animals showed a corresponding cerebral blood flow (CBF) increase. The elevated CMRO2 and CBF could be reduced to normal by administration of a beta-adrenergic receptor blocker (propranolol 2 mg/kg i.v.), and hence the increased CMRO2 during ethanol withdrawal could be related to catecholaminergic systems in the brain, e.g. the noradrenergic locus coeruleus system which is anatomically well suited as a general activating system. This interpretation is supported by the earlier neurochemical finding of an increased cerebral noradrenaline turnover during ethanol withdrawal. The exact mechanism underlying the increased cerebral oxygen consumption during ethanol withdrawal and the effect of propranolol on cerebral function during this condition remains to be clarified.

  12. Cellular defense against singlet oxygen-induced oxidative damage by cytosolic NADP+-dependent isocitrate dehydrogenase.

    Science.gov (United States)

    Kim, Sun Yee; Park, Jeen-Woo

    2003-03-01

    Singlet oxygen (1O2) is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules. Recently, we have shown that NADP+-dependent isocitrate dehydrogenase is involved in the supply of NADPH needed for GSH production against cellular oxidative damage. In this study, we investigated the role of cytosolic form of NADP+-dependent isocitrate dehydrogenase (IDPc) against singlet oxygen-induced cytotoxicity by comparing the relative degree of cellular responses in three different NIH3T3 cells with stable transfection with the cDNA for mouse IDPc in sense and antisense orientations, where IDPc activities were 2.3-fold higher and 39% lower, respectively, than that in the parental cells carrying the vector alone. Upon exposure to singlet oxygen generated from photoactivated dye, the cells with low levels of IDPc became more sensitive to cell killing. Lipid peroxidation, protein oxidation, oxidative DNA damage and intracellular peroxide generation were higher in the cell-line expressing the lower level of IDPc. However, the cells with the highly over-expressed IDPc exhibited enhanced resistance against singlet oxygen, compared to the control cells. The data indicate that IDPc plays an important role in cellular defense against singlet oxygen-induced oxidative injury.

  13. Anodal transcranial direct current stimulation transiently improves contrast sensitivity and normalizes visual cortex activation in individuals with amblyopia.

    Science.gov (United States)

    Spiegel, Daniel P; Byblow, Winston D; Hess, Robert F; Thompson, Benjamin

    2013-10-01

    Amblyopia is a neurodevelopmental disorder of vision that is associated with abnormal patterns of neural inhibition within the visual cortex. This disorder is often considered to be untreatable in adulthood because of insufficient visual cortex plasticity. There is increasing evidence that interventions that target inhibitory interactions within the visual cortex, including certain types of noninvasive brain stimulation, can improve visual function in adults with amblyopia. We tested the hypothesis that anodal transcranial direct current stimulation (a-tDCS) would improve visual function in adults with amblyopia by enhancing the neural response to inputs from the amblyopic eye. Thirteen adults with amblyopia participated and contrast sensitivity in the amblyopic and fellow fixing eye was assessed before, during and after a-tDCS or cathodal tDCS (c-tDCS). Five participants also completed a functional magnetic resonance imaging (fMRI) study designed to investigate the effect of a-tDCS on the blood oxygen level-dependent response within the visual cortex to inputs from the amblyopic versus the fellow fixing eye. A subgroup of 8/13 participants showed a transient improvement in amblyopic eye contrast sensitivity for at least 30 minutes after a-tDCS. fMRI measurements indicated that the characteristic cortical response asymmetry in amblyopes, which favors the fellow eye, was reduced by a-tDCS. These preliminary results suggest that a-tDCS deserves further investigation as a potential tool to enhance amblyopia treatment outcomes in adults.

  14. Methodological Improvements in Combining TMS and Functional MRI

    OpenAIRE

    Moisa, Marius

    2011-01-01

    Since 1997, when Bohning and colleagues demonstrated for the first time the feasibility of interleaving transcranial magnetic stimulation (TMS) with blood oxygenation level dependency functional magnetic resonance imaging (BOLD fMRI), this combination became a very promising techniques to study brain connectivity. However, the implementation of a reliable setup for interleaved TMS/fMRI is still technically challenging. In this thesis, I intended to further explore and develop methodological i...

  15. Influence of residual oxygen-15-labeled carbon monoxide radioactivity on cerebral blood flow and oxygen extraction fraction in a dual-tracer autoradiographic method.

    Science.gov (United States)

    Iwanishi, Katsuhiro; Watabe, Hiroshi; Hayashi, Takuya; Miyake, Yoshinori; Minato, Kotaro; Iida, Hidehiro

    2009-06-01

    Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO(2)), oxygen extraction fraction (OEF), and cerebral blood volume (CBV) are quantitatively measured with PET with (15)O gases. Kudomi et al. developed a dual tracer autoradiographic (DARG) protocol that enables the duration of a PET study to be shortened by sequentially administrating (15)O(2) and C(15)O(2) gases. In this protocol, before the sequential PET scan with (15)O(2) and C(15)O(2) gases ((15)O(2)-C(15)O(2) PET scan), a PET scan with C(15)O should be preceded to obtain CBV image. C(15)O has a high affinity for red blood cells and a very slow washout rate, and residual radioactivity from C(15)O might exist during a (15)O(2)-C(15)O(2) PET scan. As the current DARG method assumes no residual C(15)O radioactivity before scanning, we performed computer simulations to evaluate the influence of the residual C(15)O radioactivity on the accuracy of measured CBF and OEF values with DARG method and also proposed a subtraction technique to minimize the error due to the residual C(15)O radioactivity. In the simulation, normal and ischemic conditions were considered. The (15)O(2) and C(15)O(2) PET count curves with the residual C(15)O PET counts were generated by the arterial input function with the residual C(15)O radioactivity. The amounts of residual C(15)O radioactivity were varied by changing the interval between the C(15)O PET scan and (15)O(2)-C(15)O(2) PET scan, and the absolute inhaled radioactivity of the C(15)O gas. Using the simulated input functions and the PET counts, the CBF and OEF were computed by the DARG method. Furthermore, we evaluated a subtraction method that subtracts the influence of the C(15)O gas in the input function and PET counts. Our simulations revealed that the CBF and OEF values were underestimated by the residual C(15)O radioactivity. The magnitude of this underestimation depended on the amount of C(15)O radioactivity and the physiological conditions. This underestimation

  16. Nalmefene Reduces Reward Anticipation in Alcohol Dependence: An Experimental Functional Magnetic Resonance Imaging Study.

    Science.gov (United States)

    Quelch, Darren R; Mick, Inge; McGonigle, John; Ramos, Anna C; Flechais, Remy S A; Bolstridge, Mark; Rabiner, Eugenii; Wall, Matthew B; Newbould, Rexford D; Steiniger-Brach, Björn; van den Berg, Franz; Boyce, Malcolm; Østergaard Nilausen, Dorrit; Breuning Sluth, Lasse; Meulien, Didier; von der Goltz, Christoph; Nutt, David; Lingford-Hughes, Anne

    2017-06-01

    Nalmefene is a µ and δ opioid receptor antagonist, κ opioid receptor partial agonist that has recently been approved in Europe for treating alcohol dependence. It offers a treatment approach for alcohol-dependent individuals with "high-risk drinking levels" to reduce their alcohol consumption. However, the neurobiological mechanism underpinning its effects on alcohol consumption remains to be determined. Using a randomized, double-blind, placebo-controlled, within-subject crossover design we aimed to determine the effect of a single dose of nalmefene on striatal blood oxygen level-dependent (BOLD) signal change during anticipation of monetary reward using the monetary incentive delay task following alcohol challenge. Twenty-two currently heavy-drinking, non-treatment-seeking alcohol-dependent males were recruited. The effect of single dose nalmefene (18 mg) on changes in a priori defined striatal region of interest BOLD signal change during reward anticipation compared with placebo was investigated using functional magnetic resonance imaging. Both conditions were performed under intravenous alcohol administration (6% vol/vol infusion to achieve a target level of 80 mg/dL). Datasets from 18 participants were available and showed that in the presence of the alcohol infusion, nalmefene significantly reduced the BOLD response in the striatal region of interest compared with placebo. Nalmefene did not alter brain perfusion. Nalmefene blunts BOLD response in the mesolimbic system during anticipation of monetary reward and an alcohol infusion. This is consistent with nalmefene's actions on opioid receptors, which modulate the mesolimbic dopaminergic system, and provides a neurobiological basis for its efficacy. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

  17. Comparative evaluation of stress levels before, during, and after periodontal surgical procedures with and without nitrous oxide-oxygen inhalation sedation

    Directory of Open Access Journals (Sweden)

    Gurkirat Sandhu

    2017-01-01

    Full Text Available Context: Periodontal surgical procedures produce varying degree of stress in all patients. Nitrous oxide-oxygen inhalation sedation is very effective for adult patients with mild-to-moderate anxiety due to dental procedures and needle phobia. Aim: The present study was designed to perform periodontal surgical procedures under nitrous oxide-oxygen inhalation sedation and assess whether this technique actually reduces stress physiologically, in comparison to local anesthesia alone (LA during lengthy periodontal surgical procedures. Settings and Design: This was a randomized, split-mouth, cross-over study. Materials and Methods: A total of 16 patients were selected for this randomized, split-mouth, cross-over study. One surgical session (SS was performed under local anesthesia aided by nitrous oxide-oxygen inhalation sedation, and the other SS was performed on the contralateral quadrant under LA. For each session, blood samples to measure and evaluate serum cortisol levels were obtained, and vital parameters including blood pressure, heart rate, respiratory rate, and arterial blood oxygen saturation were monitored before, during, and after periodontal surgical procedures. Statistical Analysis Used: Paired t-test and repeated measure ANOVA. Results: The findings of the present study revealed a statistically significant decrease in serum cortisol levels, blood pressure and pulse rate and a statistically significant increase in respiratory rate and arterial blood oxygen saturation during periodontal surgical procedures under nitrous oxide inhalation sedation. Conclusion: Nitrous oxide-oxygen inhalation sedation for periodontal surgical procedures is capable of reducing stress physiologically, in comparison to LA during lengthy periodontal surgical procedures.

  18. Unravelling spatiotemporal tree-ring signals in Mediterranean oaks: a variance-covariance modelling approach of carbon and oxygen isotope ratios.

    Science.gov (United States)

    Shestakova, Tatiana A; Aguilera, Mònica; Ferrio, Juan Pedro; Gutiérrez, Emilia; Voltas, Jordi

    2014-08-01

    Identifying how physiological responses are structured across environmental gradients is critical to understanding in what manner ecological factors determine tree performance. Here, we investigated the spatiotemporal patterns of signal strength of carbon isotope discrimination (Δ(13)C) and oxygen isotope composition (δ(18)O) for three deciduous oaks (Quercus faginea (Lam.), Q. humilis Mill. and Q. petraea (Matt.) Liebl.) and one evergreen oak (Q. ilex L.) co-occurring in Mediterranean forests along an aridity gradient. We hypothesized that contrasting strategies in response to drought would lead to differential climate sensitivities between functional groups. Such differential sensitivities could result in a contrasting imprint on stable isotopes, depending on whether the spatial or temporal organization of tree-ring signals was analysed. To test these hypotheses, we proposed a mixed modelling framework to group isotopic records into potentially homogeneous subsets according to taxonomic or geographical criteria. To this end, carbon and oxygen isotopes were modelled through different variance-covariance structures for the variability among years (at the temporal level) or sites (at the spatial level). Signal-strength parameters were estimated from the outcome of selected models. We found striking differences between deciduous and evergreen oaks in the organization of their temporal and spatial signals. Therefore, the relationships with climate were examined independently for each functional group. While Q. ilex exhibited a large spatial dependence of isotopic signals on the temperature regime, deciduous oaks showed a greater dependence on precipitation, confirming their higher susceptibility to drought. Such contrasting responses to drought among oak types were also observed at the temporal level (interannual variability), with stronger associations with growing-season water availability in deciduous oaks. Thus, our results indicate that Mediterranean deciduous

  19. Cerebral blood flow, oxygen and glucose metabolism with PET in progressive supranuclear palsy

    International Nuclear Information System (INIS)

    Otsuka, Makoto; Ichiya, Yuici; Kuwabara, Yasuo

    1989-01-01

    Cerebral blood flow, cerebral oxygen metabolic rate and cerebral glucose metabolic rate were measured with positron emission tomography (PET) in four patients with progressive supranuclear palsy (PSP). Decreased blood flow and hypometabolism of oxygen and glucose were found in both subcortical and cortical regions, particularly in the striatum including the head of the caudate nucleus and the frontal cortex. The coupling between blood flow and metabolism was preserved even in the regions which showed decreased blood flow and hypometabolism. These findings indicated the hypofunction, as revealed by decreased blood flow and hypometablolism on PET, both in the striatum and the frontal cortex, and which may underlie the pathophysiological mechanism of motor and mental disturbance in PSP. (author)

  20. Significance of myoglobin as an oxygen store and oxygen transporter in the intermittently perfused human heart: a model study.

    Science.gov (United States)

    Endeward, Volker; Gros, Gerolf; Jürgens, Klaus D

    2010-07-01

    The mechanisms by which the left ventricular wall escapes anoxia during the systolic phase of low blood perfusion are investigated, especially the role of myoglobin (Mb), which can (i) store oxygen and (ii) facilitate intracellular oxygen transport. The quantitative role of these two Mb functions is studied in the maximally working human heart. Because discrimination between Mb functions has not been achieved experimentally, we use a Krogh cylinder model here. At a heart rate of 200 beats/min and a 1:1 ratio of diastole/systole, the systole lasts for 150 ms. The basic model assumption is that, with mobile Mb, the oxygen stored in the end-diastolic left ventricle wall exactly meets the demand during the 150 ms of systolic cessation of blood flow. The coronary blood flow necessary to achieve this agrees with literature data. By considering Mb immobile or setting its concentration to zero, respectively, we find that, depending on Mb concentration, Mb-facilitated O(2) transport maintains O(2) supply to the left ventricle wall during 22-34 of the 150 ms, while Mb storage function accounts for a further 12-17 ms. When Mb is completely absent, anoxia begins to develop after 116-99 ms. While Mb plays no significant role during diastole, it supplies O(2) to the left ventricular wall for < or = 50 ms of the 150 ms systole, whereas capillary haemoglobin is responsible for approximately 80 ms. Slight increases in haemoglobin concentration, blood flow, or capillary density can compensate the absence of Mb, a finding which agrees well with the observations using Mb knockout mice.

  1. Dialysis and contrast media

    International Nuclear Information System (INIS)

    Morcos, Sameh K.; Thomsen, Henrik S.; Webb, Judith A.W.

    2002-01-01

    In a previous survey we revealed uncertainty among responders about (a) whether or not to perform hemodialysis in patients with severely reduced renal function who had received contrast medium; and (b) when to perform hemodialysis in patients on regular treatment with hemodialysis or continuous ambulatory dialysis who received contrast medium. Therefore, the Contrast Media Safety Committee of The European Society of Urogenital Radiology decided to review the literature and to issue guidelines. The committee performed a Medline search. Based on this, a report and guidelines were prepared. The report was discussed at the Ninth European Symposium on Urogenital Radiology in Genoa, Italy. Hemodialysis and peritoneal dialysis safely remove both iodinated and gadolinium-based contrast media. The effectiveness of hemodialysis depends on many factors including blood and dialysate flow rate, permeability of dialysis membrane, duration of hemodialysis and molecular size, protein binding, hydrophilicity, and electrical charge of the contrast medium. Generally, several hemodialysis sessions are needed to removal all contrast medium, whereas it takes 3 weeks for continuous ambulatory dialysis to remove the agent completely. There is no need to schedule the dialysis in relation to the injection of iodinated or MR contrast media or the injection of contrast agent in relation to the dialysis program. Hemodialysis does not protect poorly functioning kidneys against contrast-medium-induced nephrotoxicity. Simple guidelines are given. (orig.)

  2. Relationship between blood pressure, cognitive function and education level in elderly patients with diabetes: a preliminary study.

    Science.gov (United States)

    Talfournier, J; Bitu, J; Paquet, C; Gobron, C; Guillausseau, P J; Hugon, J; Dumurgier, J

    2013-10-01

    This study aimed to assess the relationship between blood pressure and cognitive function in elderly patients with diabetes mellitus (DM). A total of 32 patients with DM aged ≥ 65 years (seven women and 25 men; mean ± SD age: 74.3 ± 6.4 years) were included in this cross-sectional study. Relationships between blood pressure and neuropsychological tests were determined using Spearman's rank correlations (ρ) and multivariable linear regression models. Lower diastolic blood pressure was associated with lower scores on the Frontal Assessment Battery (ρ=0.32, P=0.02), longer times to complete the Trail Making Test Part B (ρ=0.51, P=0.003), lower scores for the Finger Tapping Test (ρ=0.36, P=0.046) and less verbal fluency (ρ=0.36, P=0.047). In multivariable models, these relationships were attenuated after adjusting for levels of education. There was an association between lower diastolic blood pressure and poorer executive function in this cohort of elderly DM patients. These results underline the importance of systematic cognitive evaluation in elderly patients with DM, and suggest that a too-low diastolic blood pressure may have deleterious effects on mental function. Larger studies in the future are required to confirm these preliminary results. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  3. Blood lead levels and chronic blood loss

    Energy Technology Data Exchange (ETDEWEB)

    Manci, E.A.; Cabaniss, M.L.; Boerth, R.C.; Blackburn, W.R.

    1986-03-01

    Over 90% of lead in blood is bound to the erythrocytes. This high affinity of lead for red cells may mean that chronic blood loss is a significant means for excretion of lead. This study sought correlations between blood lead levels and clinical conditions involving chronic blood loss. During May, June and July, 146 patients with normal hematocrits and red cell indices were identified from the hospital and clinic populations. For each patient, age, race, sex and medical history were noted, and a whole blood sample was analyzed by flameless atomic absorption spectrophotometry. Age-and race-matched pairs showed a significant correlation of chronic blood loss with lead levels. Patients with the longest history of blood loss (menstruating women) had the lowest level (mean 6.13 ..mu..g/dl, range 3.6-10.3 ..mu..g/dl). Post-menopausal women had levels (7.29 ..mu..g/dl, 1.2-14 ..mu..g/dl) comparable to men with peptic ulcer disease, or colon carcinoma (7.31 ..mu..g/dl, 5.3-8.6 ..mu..g/dl). The highest levels were among men who had no history of bleeding problems (12.39 ..mu..g/dl, 2.08-39.35 ..mu..g/dl). Chronic blood loss may be a major factor responsible for sexual differences in blood lead levels. Since tissue deposition of environmental pollutants is implicated in diseases, menstruation may represent a survival advantage for women.

  4. Alteration of Blood Flow in a Venular Network by Infusion of Dextran 500: Evaluation with a Laser Speckle Contrast Imaging System.

    Science.gov (United States)

    Namgung, Bumseok; Ng, Yan Cheng; Nam, Jeonghun; Leo, Hwa Liang; Kim, Sangho

    2015-01-01

    This study examined the effect of dextran-induced RBC aggregation on the venular flow in microvasculature. We utilized the laser speckle contrast imaging (LSCI) as a wide-field imaging technique to visualize the flow distribution in venules influenced by abnormally elevated levels of RBC aggregation at a network-scale level, which was unprecedented in previous studies. RBC aggregation in rats was induced by infusing Dextran 500. To elucidate the impact of RBC aggregation on microvascular perfusion, blood flow in the venular network of a rat cremaster muscle was analyzed with a stepwise reduction of the arterial pressure (100 → 30 mmHg). The LSCI analysis revealed a substantial decrease in the functional vascular density after the infusion of dextran. The relative decrease in flow velocity after dextran infusion was notably pronounced at low arterial pressures. Whole blood viscosity measurements implied that the reduction in venular flow with dextran infusion could be due to the elevation of medium viscosity in high shear conditions (> 45 s-1). In contrast, further augmentation to the flow reduction at low arterial pressures could be attributed to the formation of RBC aggregates (networks.

  5. Parameters of Blood Flow in Great Arteries in Hypertensive ISIAH Rats with Stress-Dependent Arterial Hypertension.

    Science.gov (United States)

    Seryapina, A A; Shevelev, O B; Moshkin, M P; Markel', A L

    2016-08-01

    Magnetic resonance angiography was used to examine blood flow in great arteries of hypertensive ISIAH and normotensive Wistar rats. In hypertensive ISIAH rats, increased vascular resistance in the basin of the abdominal aorta and renal arteries as well as reduced fraction of total renal blood flow were found. In contrast, blood flow through both carotid arteries in ISIAH rats was enhanced, which in suggests more intensive blood supply to brain regulatory centers providing enhanced stress reactivity of these rats characterized by stress-dependent arterial hypertension.

  6. Magnetic resonance angiography with blood-pool contrast agents: future applications

    International Nuclear Information System (INIS)

    Fink, C.; Goyen, M.; Lotz, J.

    2007-01-01

    Blood pool agents remain in the intravascular space for a longer time period. Therefore the optimal imaging window for vascular structures is widened to about 30 minutes. Gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany) is the first blood-pool contrast agent approved in Europe for contrast-enhanced magnetic resonance angiography (MRA) of vessels in the abdomen, pelvis and lower extremity in adults. Other possible applications of blood-pool agents are now being considered, such as assessment of venous thromboembolism, coronary artery disease or sinus venous thrombosis. Perfusion MR imaging holds promise for detecting lung perfusion defects with higher spatial resolution and reduced scan time compared with radionuclide scintigraphy. In coronary artery disease, blood-pool agents enable a substantial increase in the quality of coronary artery imaging. Quantitative myocardial perfusion and myocardial viability seem to be possible, although modifications in protocols and sequence design are necessary for optimal results. Other novel applications of blood-pool agents include monitoring of inflammatory changes in systemic lupus erythematosus and evaluation of tumour invasion into lymph nodes and more reliable assessment of cerebral venous and sinus thrombosis. (orig.)

  7. Magnetic resonance angiography with blood-pool contrast agents: future applications

    Energy Technology Data Exchange (ETDEWEB)

    Fink, C. [Univ. Hospitals, Grosshadern, Munich (Germany); Goyen, M. [Univ. Medical Center, Hamburg-Eppendorf, Hamburg (Germany); Lotz, J. [Hannover Medical School, Hannover (Germany)

    2007-03-15

    Blood pool agents remain in the intravascular space for a longer time period. Therefore the optimal imaging window for vascular structures is widened to about 30 minutes. Gadofosveset trisodium (Vasovist, Bayer Schering Pharma AG, Berlin, Germany) is the first blood-pool contrast agent approved in Europe for contrast-enhanced magnetic resonance angiography (MRA) of vessels in the abdomen, pelvis and lower extremity in adults. Other possible applications of blood-pool agents are now being considered, such as assessment of venous thromboembolism, coronary artery disease or sinus venous thrombosis. Perfusion MR imaging holds promise for detecting lung perfusion defects with higher spatial resolution and reduced scan time compared with radionuclide scintigraphy. In coronary artery disease, blood-pool agents enable a substantial increase in the quality of coronary artery imaging. Quantitative myocardial perfusion and myocardial viability seem to be possible, although modifications in protocols and sequence design are necessary for optimal results. Other novel applications of blood-pool agents include monitoring of inflammatory changes in systemic lupus erythematosus and evaluation of tumour invasion into lymph nodes and more reliable assessment of cerebral venous and sinus thrombosis. (orig.)

  8. Effects of computed tomography contrast medium factors on contrast enhancement

    International Nuclear Information System (INIS)

    Terasawa, Kazuaki; Hatcho, Atsushi; Okuda, Itsuko

    2011-01-01

    The various nonionic iodinated contrast media used in contrast computed tomography (CT) studies differ in terms of their composition, characteristics, and iodine concentration (mgI/ml), as well as the volume injected (ml). Compared with ionic iodinated contrast media, nonionic iodinated contrast media are low-osmolar agents, with different agents having different osmotic pressures. Using a custom-made phantom incorporating a semipermeable membrane, the osmotic flow rate (hounsfield unit (HU)/s) could easily be measured based on the observed increase in CT numbers, and the relationship between the osmotic pressure and the osmotic flow rate could be obtained (r 2 =0.84). In addition, taking the effects of patient size into consideration, the levels of contrast enhancement in the abdominal aorta (AA) and inferior vena cava (IVC) were compared among four types of CT contrast medium. The results showed differences in contrast enhancement in the IVC during the equilibrium phase depending on the type of contrast medium used. It was found that the factors responsible for the differences observed in enhancement in the IVC were the osmotic flow rate and the volume of the blood flow pathways in the circulatory system. It is therefore considered that the reproducibility of contrast enhancement is likely to be reduced in the examination of parenchymal organs, in which scanning must be performed during the equilibrium phase, even if the amount of iodine injected per unit body weight (mgI/kg) is maintained at a specified level. (author)

  9. Variation in levels of reactive oxygen species is explained by maternal identity, sex and body-size-corrected clutch size in a lizard

    Science.gov (United States)

    Olsson, Mats; Wilson, Mark; Uller, Tobias; Mott, Beth; Isaksson, Caroline

    2009-01-01

    Many organisms show differences between males and females in growth rate and crucial life history parameters, such as longevity. Considering this, we may expect levels of toxic metabolic by-products of the respiratory chain, such as reactive oxygen species (ROS), to vary with age and sex. Here, we analyse ROS levels in female Australian painted dragon lizards ( Ctenophorus pictus) and their offspring using fluorescent probes and flow cytometry. Basal level of four ROS species (singlet oxygen, peroxynitrite, superoxide and H2O2) measured with a combined marker, and superoxide measured specifically, varied significantly among families but not between the sexes. When blood cells from offspring were chemically encouraged to accelerate the electron transport chain by mitochondrial uncoupling, net superoxide levels were three times higher in daughters than sons (resulting in levels outside of the normal ROS range) and varied among mothers depending on offspring sex (significant interaction between maternal identity and offspring sex). In offspring, there were depressive effects on ROS of size-controlled relative clutch size, which relies directly on circulating levels of vitellogenin, a confirmed antioxidant in some species. Thus, levels of reactive oxygen species varies among females, offspring and in relation to reproductive investment in a manner that makes its regulatory processes likely targets of selection.

  10. Early graft function and carboxyhemoglobin level in liver transplanted patients.

    Science.gov (United States)

    Ali, Yasser; Negmi, H; Elmasry, N; Sadek, M; Riaz, A; Al Ouffi, H; Khalaf, H

    2007-10-01

    Heme-Oxygenase-1 catalyzes hemoglobin into bilirubin, iron, and carbon monoxide, a well known vasodilator. Heme-Oxygenase-1 expression and carbon monoxide production as measured by blood carboxyhemoglobin levels, increase in end stage liver disease patients. We hypothesized that there may be a correlation between carboxyhemoglobin level and early graft function in patients undergoing liver transplant surgeries. In a descriptive retrospective study, 39 patients who underwent liver transplantation between the year 2005 and 2006 at KFSH&RC, are included in the study. All patients received general anesthesia with isoflurane in 50% oxygen and air. Levels of oxyhemoglobin, carboxyhemoglobin and methemoglobin concentration in percentage were recorded at preoperative time, anhepatic phase, end of surgery, ICU admission and 24 hr after surgery. The level of lactic acid, prothrombin time (PT), partial thrombin time (PTT), serum total bilirubin and ammonia were also recorded at ICU admission and 24 hr after surgery. The numbers of blood units transfused were recorded. 39 patients were included in the study with 13/39 for living donor liver transplant (LDLT) compared to 26/39 patients scheduled for deceased donor liver transplant (DDLT). The mean age was 35.9 +/- 16.9 years while the mean body weight was 60.3 +/- 20.9 Kg. Female to male ratio was 21/18. The median packed red blood cell (PRBC) units was 4 (Rang 0-40). There was a significant increase in carboxyhemoglobin level during the anhepatic phase, end of surgery and on ICU admission compared with preoperative value (pcarboxyhemoglobin level on ICU admission and 24 hrs postoperatively were positively correlated with the changes in serum total bilirubin and prothrombin time (R = 0.35, 0.382, 0.325 and 0.31) respectively pcarboxyhemoglobin concentration and PT and total bilirubin while still the correlation with lactic acid was weak. There was no correlation between average perioperative carboxyhemoglobin concentration

  11. Bisphenol S impairs blood functions and induces cardiovascular risks in rats

    Directory of Open Access Journals (Sweden)

    Sanghamitra Pal

    Full Text Available Bisphenol S (BPS is an industrial chemical which is recently used to replace the potentially toxic Bisphenol A (BPA in making polycarbonate plastics, epoxy resins and thermal receipt papers. The probable toxic effects of BPS on the functions of haemopoietic and cardiovascular systems have not been reported till to date. We report here that BPS depresses haematological functions and induces cardiovascular risks in rat. Adult male albino rats of Sprague-Dawley strain were given BPS at a dose level of 30, 60 and 120 mg/kg BW/day respectively for 30 days. Red blood cell (RBC count, white blood cell (WBC count, Hb concentration, and clotting time have been shown to be significantly (*P < 0.05 reduced in a dose dependent manner in all exposed groups of rats comparing to the control. It has also been shown that BPS increases total serum glucose and protein concentration in the exposed groups of rats. We have observed that BPS increases serum total cholesterol, triglyceride, glycerol free triglyceride, low density lipoprotein (LDL and very low density lipoprotein (VLDL concentration, whereas high density lipoprotein (HDL concentration has been found to be reduced in the exposed groups. BPS significantly increases serum aspartate aminotransferase (AST, alanine aminotransferase (ALT and alkaline phosphatase (ALP activities dose dependently. Moreover, serum calcium, bilirubin and urea concentration have been observed to be increased in all exposed groups. In conclusion, BPS probably impairs the functions of blood and promotes cardiovascular risks in rats. Keywords: Bisphenol S, Red blood cell count, White blood cell count, Clotting time, LDL cholesterol, HDL cholesterol, Cardiovascular risks

  12. Parity dependence of the nuclear level density at high excitation

    International Nuclear Information System (INIS)

    Rao, B.V.; Agrawal, H.M.

    1995-01-01

    The basic underlying assumption ρ(l+1, J)=ρ(l, J) in the level density function ρ(U, J, π) has been checked on the basis of high quality data available on individual resonance parameters (E 0 , Γ n , J π ) for s- and p-wave neutrons in contrast to the earlier analysis where information about p-wave resonance parameters was meagre. The missing level estimator based on the partial integration over a Porter-Thomas distribution of neutron reduced widths and the Dyson-Mehta Δ 3 statistic for the level spacing have been used to ascertain that the s- and p-wave resonance level spacings D(0) and D(1) are not in error because of spurious and missing levels. The present work does not validate the tacit assumption ρ(l+1, J)=ρ(l, J) and confirms that the level density depends upon parity at high excitation. The possible implications of the parity dependence of the level density on the results of statistical model calculations of nuclear reaction cross sections as well as on pre-compound emission have been emphasized. (orig.)

  13. Relationships between human vitality and mitochondrial respiratory parameters, reactive oxygen species production and dNTP levels in peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Maynard, Scott; Keijzers, Guido; Gram, Martin

    2013-01-01

    . Therefore, we measured a number of cellular parameters related to mitochondrial activity in peripheral blood mononuclear cells (PBMCs) isolated from middle-aged men, and tested for association with vitality. These parameters estimate mitochondrial respiration, reactive oxygen species (ROS) production...

  14. Cerebral blood flow and metabolism during exercise: implications for fatigue

    DEFF Research Database (Denmark)

    Seifert, T.; Lieshout, J.J. van; Secher, Niels

    2008-01-01

    During exercise: the Kety-Schmidt-determined cerebral blood flow (CBF) does not change because the jugular vein is collapsed in the upright position. In contrast, when CBF is evaluated by (133)Xe clearance, by flow in the internal carotid artery, or by flow velocity in basal cerebral arteries......, a approximately 25% increase is detected with a parallel increase in metabolism. During activation, an increase in cerebral O(2) supply is required because there is no capillary recruitment within the brain and increased metabolism becomes dependent on an enhanced gradient for oxygen diffusion. During maximal...... whole body exercise, however, cerebral oxygenation decreases because of eventual arterial desaturation and marked hyperventilation-related hypocapnia of consequence for CBF. Reduced cerebral oxygenation affects recruitment of motor units, and supplemental O(2) enhances cerebral oxygenation and work...

  15. Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

    Science.gov (United States)

    Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

    2017-08-01

    This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

  16. Effect of ionic and non-ionic contrast media on whole blood viscosity, plasma viscosity and hematocrit in vitro

    International Nuclear Information System (INIS)

    Aspelin, P.

    1978-01-01

    The effect of the ionic contrast media diatrizoate, iocarmate and metrizoate and the non-ionic metrizamide on whole blood viscosity, plasma viscosity and hematocrit was investigated. All the contrast media increased whole blood and plasma viscosity and reduced the hematocrit. The whole blood viscosity increased with increasing osmolality of the contrast medium solutions, whereas the plasma viscosity increased with increasing viscosity of the contrast medium solutions. The higher the osmolality of the contrast media, the lower the hematocrit became. The normal shear-thinning (decreasing viscosity with increasing shear rate) property of blood was reduced when contrast medium was added to the blood. At 50 per cent volume ratio (contrast medium to blood), the ionic contrast media converted the blood into a shear-thickening (increasing viscosity with increasing shear rate) suspension, indicating a marked rigidification of the single red cell, while the non-ionic contrast medium still produced shear-thinning, indicating less rigidification of the red cell (p<0.01). (Auth.)

  17. Capturing age-related changes in functional contrast sensitivity with decreasing light levels in monocular and binocular vision.

    Science.gov (United States)

    Gillespie-Gallery, Hanna; Konstantakopoulou, Evgenia; Harlow, Jonathan A; Barbur, John L

    2013-09-09

    It is challenging to separate the effects of normal aging of the retina and visual pathways independently from optical factors, decreased retinal illuminance, and early stage disease. This study determined limits to describe the effect of light level on normal, age-related changes in monocular and binocular functional contrast sensitivity. We recruited 95 participants aged 20 to 85 years. Contrast thresholds for correct orientation discrimination of the gap in a Landolt C optotype were measured using a 4-alternative, forced-choice (4AFC) procedure at screen luminances from 34 to 0.12 cd/m(2) at the fovea and parafovea (0° and ±4°). Pupil size was measured continuously. The Health of the Retina index (HRindex) was computed to capture the loss of contrast sensitivity with decreasing light level. Participants were excluded if they exhibited performance outside the normal limits of interocular differences or HRindex values, or signs of ocular disease. Parafoveal contrast thresholds showed a steeper decline and higher correlation with age at the parafovea than the fovea. Of participants with clinical signs of ocular disease, 83% had HRindex values outside the normal limits. Binocular summation of contrast signals declined with age, independent of interocular differences. The HRindex worsens more rapidly with age at the parafovea, consistent with histologic findings of rod loss and its link to age-related degenerative disease of the retina. The HRindex and interocular differences could be used to screen for and separate the earliest stages of subclinical disease from changes caused by normal aging.

  18. Effects of the Oxygen-Carrying Solution OxyVita C on the Cerebral Microcirculation and Systemic Blood Pressures in Healthy Rats

    Directory of Open Access Journals (Sweden)

    Rania Abutarboush

    2014-11-01

    Full Text Available The use of hemoglobin-based oxygen carriers (HBOC as oxygen delivering therapies during hypoxic states has been hindered by vasoconstrictive side effects caused by depletion of nitric oxide (NO. OxyVita C is a promising oxygen-carrying solution that consists of a zero-linked hemoglobin polymer with a high molecular weight (~17 MDa. The large molecular weight is believed to prevent extravasation and limit NO scavenging and vasoconstriction. The aim of this study was to assess vasoactive effects of OxyVita C on systemic blood pressures and cerebral pial arteriole diameters. Anesthetized healthy rats received four intravenous (IV infusions of an increasing dose of OxyVita C (2, 25, 50, 100 mg/kg and hemodynamic parameters and pial arteriolar diameters were measured pre- and post-infusion. Normal saline was used as a volume-matched control. Systemic blood pressures increased (P ≤ 0.05 with increasing doses of OxyVita C, but not with saline. There was no vasoconstriction in small (<50 µm and medium-sized (50–100 µm pial arterioles in the OxyVita C group. In contrast, small and medium-sized pial arterioles vasoconstricted in the control group. Compared to saline, OxyVita C showed no cerebral vasoconstriction after any of the four doses evaluated in this rat model despite increases in blood pressure.

  19. The power of using functional fMRI on small rodents to study brain pharmacology and disease

    OpenAIRE

    Jonckers, Elisabeth; Shah, Disha; Hamaide, Julie; Verhoye, Marleen; Van der Linden, Annemie

    2015-01-01

    Abstract: Functional magnetic resonance imaging (fMRI) is an excellent tool to study the effect of pharmacological modulations on brain function in a non-invasive and longitudinal manner. We introduce several blood oxygenation level dependent (BOLD) fMRI techniques, including resting state (rsfMRI), stimulus-evoked (st-fMRI), and pharmacological MRI (phMRI). Respectively, these techniques permit the assessment of functional connectivity during rest as well as brain activation triggered by sen...

  20. Factors associated with blood oxygen partial pressure and carbon dioxide partial pressure regulation during respiratory extracorporeal membrane oxygenation support: data from a swine model.

    Science.gov (United States)

    Park, Marcelo; Mendes, Pedro Vitale; Costa, Eduardo Leite Vieira; Barbosa, Edzangela Vasconcelos Santos; Hirota, Adriana Sayuri; Azevedo, Luciano Cesar Pontes

    2016-01-01

    The aim of this study was to explore the factors associated with blood oxygen partial pressure and carbon dioxide partial pressure. The factors associated with oxygen - and carbon dioxide regulation were investigated in an apneic pig model under veno-venous extracorporeal membrane oxygenation support. A predefined sequence of blood and sweep flows was tested. Oxygenation was mainly associated with extracorporeal membrane oxygenation blood flow (beta coefficient = 0.036mmHg/mL/min), cardiac output (beta coefficient = -11.970mmHg/L/min) and pulmonary shunting (beta coefficient = -0.232mmHg/%). Furthermore, the initial oxygen partial pressure and carbon dioxide partial pressure measurements were also associated with oxygenation, with beta coefficients of 0.160 and 0.442mmHg/mmHg, respectively. Carbon dioxide partial pressure was associated with cardiac output (beta coefficient = 3.578mmHg/L/min), sweep gas flow (beta coefficient = -2.635mmHg/L/min), temperature (beta coefficient = 4.514mmHg/ºC), initial pH (beta coefficient = -66.065mmHg/0.01 unit) and hemoglobin (beta coefficient = 6.635mmHg/g/dL). In conclusion, elevations in blood and sweep gas flows in an apneic veno-venous extracorporeal membrane oxygenation model resulted in an increase in oxygen partial pressure and a reduction in carbon dioxide partial pressure 2, respectively. Furthermore, without the possibility of causal inference, oxygen partial pressure was negatively associated with pulmonary shunting and cardiac output, and carbon dioxide partial pressure was positively associated with cardiac output, core temperature and initial hemoglobin.

  1. Brain Functional Connectivity in MS: An EEG-NIRS Study

    Science.gov (United States)

    2015-10-01

    1 AWARD NUMBER: W81XWH-14-1-0582 TITLE: Brain Functional Connectivity in MS: An EEG -NIRS Study PRINCIPAL INVESTIGATOR: Heather Wishart...Functional Connectivity in MS: An EEG -NIRS Study 5b. GRANT NUMBER W81XWH-14-1-0582 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Heather...electrical ( EEG ) and blood volume and blood oxygen-based (NIRS and fMRI) signals, and to use the results to help optimize blood oxygen level

  2. Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

    DEFF Research Database (Denmark)

    Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

    2010-01-01

    The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

  3. Regulation of singlet oxygen-induced apoptosis by cytosolic NADP+-dependent isocitrate dehydrogenase.

    Science.gov (United States)

    Kim, Sun Yee; Lee, Su Min; Tak, Jean Kyoung; Choi, Kyeong Sook; Kwon, Taeg Kyu; Park, Jeen-Woo

    2007-08-01

    Singlet oxygen is a highly reactive form of molecular oxygen that may harm living systems by oxidizing critical cellular macromolecules and it also promotes deleterious processes such as cell death. Recently, we demonstrated that the control of redox balance and the cellular defense against oxidative damage are the primary functions of cytosolic NADP(+)-dependent isocitrate dehydrogenase (IDPc) through supplying NADPH for antioxidant systems. In this report, we demonstrate that modulation of IDPc activity in HL-60 cells regulates singlet oxygen-induced apoptosis. When we examined the protective role of IDPc against singlet oxygen-induced apoptosis with HL-60 cells transfected with the cDNA for mouse IDPc in sense and antisense orientations, a clear inverse relationship was observed between the amount of IDPc expressed in target cells and their susceptibility to apoptosis. The results suggest that IDPc plays an important protective role in apoptosis of HL-60 cells induced by singlet oxygen.

  4. On the dependence of centre-to-limb contrast function of the photospheric faculae on their brightness

    International Nuclear Information System (INIS)

    Akimov, L.A.; Belkina, I.L.; Dyatel, N.P.

    1988-01-01

    The photometric aspect of the facular model with horizontal inhomogeneities is considered. The modeling of such inhomogeneities can be represented by a relative shift along the sun radius of neighbouring in heliocentric angle Θ photospheric regions by the value of the optical depth Δτ. It is found that the calculated faculae contrast curve in continuum (λ ≅ 5000 A) depends sensitively on the size ratio of rising and sinking elements and on their relative shift in the optical depth. This causes the change of the peak in the contrast curve and in its intensity. The size of elements influences th contrast curve but slightly. The calculated contrast curve for Δτ=0,8 and for the size ratio of rising and sinking elements equal to 1 is in a good agreement with the observed contrast curve for strong faculae. The observed contrast curve for faint faculae gives a good fit to the calculated contrast curve for Δτ=0,4 and for the size ratio of rising and sinking structures equal to 1/5

  5. Temperature-dependent enthalpy of oxygenation in Antarctic fish hemoglobins

    DEFF Research Database (Denmark)

    Fago, A.; Wells, R.M.G.; Weber, Roy E.

    1997-01-01

    The effect of temperature on the oxygen-binding properties of the hemoglobins of three cold-adapted Antarctic fish species, Dissostichus mawsoni, Pagothenia borchgrevinki and Trematomus, sp., has been investigated under different pH values and buffer conditions. A clear non linear van't Hoff plot...... (logP(50) vs 1/T) of D. mawsoni hemoglobin indicates that the enthalpy of oxygenation (slope of the plot) is temperature dependent and that at high temperatures oxygen-binding becomes less exothermic. Nearly linear relationships were found in the hemoglobins of the other two species. The data were...... oxygen binding. The degree of the temperature dependence of the heat of oxygenation observed in these hemoglobins seems to reflect the differences in their allosteric effects rather than a specific molecular adaptation to low temperatures. Moreover, this study indicates that the disagreement between...

  6. The continuous inhalation of oxygen-15 for assessing regional oxygen extraction in the brain of man

    International Nuclear Information System (INIS)

    Jones, T.; Chesler, D.A.; Ter-Pogossian, M.M.

    1976-01-01

    A non-invasive steady-state method for studying the regional accumulation of oxygen in the brain by continuously inhaling oxygen-15 has been investigated. Oxygen respiration by tissue results in the formation of water of metabolism which may be considered as the 'exhaust product' of respiration. In turn the steady-state distribution of this product may be related to that of oxygen utilization. It has been found in monkeys than an appreciable component of the signal, recorded over the head during the inhalation of 15 O 2 , was attributable to the local production of 15 O-labelled water of metabolism. In man the distribution of radioactivity recorded over the head during 15 O 2 inhalation clearly related to active cerebal tissue. Theoretically the respiration product is linearly dependent on the oxygen extraction ratio of the tissue, and at normal cerebal perfusion it is less sensitive to changes in blood flow. At low rates of perfusion a more linear dependence on flow is shown. The dual dependence on blood flow and oxygen extraction limited the interpretation of the cerebal distribution obtained with this technique. Means for obtaining more definitive measurements with this approach are discussed. (author)

  7. Cytogenetic analysis of peripheral blood lymphocytes after arteriography (exposure to x-rays and contrast medium)

    International Nuclear Information System (INIS)

    Popova, L.; Hadjidekova, V.; Karadjov, G.; Agova, S.; Traskov, D.; Hadjidekov, V.

    2005-01-01

    Backgrounds. The purpose of our study is to investigate the cytogenetic analysis findings in peripheral blood lymphocytes of 29 patients who had undergone diagnostic radiography. Methods. Peripheral blood samples were taken from 22 patients submitted to renal arteriography and 7 patients submitted to cerebral arteriography (17 male and 12 female, aged between 13-68 years). Cytogenetic analyses of peripheral lymphocytes were performed before the procedure, immediately after and 24 hours later. The entrance skin dose obtained during the whole diagnostic X-ray exposure was measured by thermoluminescent dosimeters and varied between 0.03-0.30 Gy. Both low and high osmolarity contrast media were used. Chromosomal aberrations and micronuclei frequency were used as biomarkers of genotoxicity. Results. The estimated frequency of chromosomal aberrations and micronuclei in the peripheral blood lymphocytes of patients after arteriography examination was significantly higher than the level before the diagnostic exposure. The mean frequency of cells with chromosomal aberrations was nearly double after examination and proved to be constant in the analysis after 24 hours. Conclusions. Radiological diagnostic procedures involving iodinated contrast media as arteriography may cause a significant increase in cytogenetic damage in peripheral blood lymphocytes. (author)

  8. Cytogenetic analysis in peripheral blood lymphocytes after arteriography (exposure to X-rays and contrast medium)

    International Nuclear Information System (INIS)

    Hadjidekova, V.; Popova, L.; Hristova, R.; Hadjidekov, V.

    2006-01-01

    Full text: The purpose of our study is to investigate the cytogenetic effects in peripheral blood lymphocytes of 29 patients who had undergone diagnostic angiography. Peripheral blood samples were taken from 22 patients submitted to renal arteriography and 7 patients submitted to cerebral arteriography (17 male and 12 female, aged between 13 and 68 years). Cytogenetic analysis was performed in peripheral lymphocytes before the procedure, immediately after and 24 hours later. The entrance skin dose obtained during the whole diagnostic X-ray exposure was measured by thermoluminescent dosimeters and varied between 0.03 - 0.30 Gy. Both low and high osmolarity contrast media were used. Chromosomal aberrations and micronuclei frequency was used as biomarkers of genotoxicity. The estimated frequency of chromosomal aberrations and micronuclei in peripheral blood lymphocytes of patients after arteriography examination is significantly higher than the level before the diagnostic exposure. The mean frequency of cells with chromosomal aberrations nearly double after examination and remained constant at 24h analysis. Radiological diagnostic procedures involving iodinated contrast media as arteriography may cause a significant increase of the cytogenetic injury in peripheral blood lymphocytes

  9. Blood flow and tissue oxygen pressures of liver and pancreas in rats: effects of volatile anesthetics and of hemorrhage.

    Science.gov (United States)

    Vollmar, B; Conzen, P F; Kerner, T; Habazettl, H; Vierl, M; Waldner, H; Peter, K

    1992-09-01

    The object of this investigation was to compare the effects of volatile anesthetics and of hemorrhage at comparable arterial blood pressures on splanchnic blood flow (radioactive microspheres) and tissue oxygenation of the liver and pancreas (surface PO2 [PSO2] electrodes). In contrast to earlier studies, we did not use identical minimum alveolar anesthetic concentration multiples as a reference to compare volatile anesthetics; rather, we used the splanchnic perfusion pressure. Under general anesthesia (intravenous chloralose) and controlled ventilation, 12 Sprague-Dawley rats underwent laparotomy to allow access to abdominal organs. Mean arterial pressure was decreased from 84 +/- 3 mm Hg (mean +/- SEM) at control to 50 mm Hg by 1.0 +/- 0.1 vol% halothane, 2.2 +/- 0.2 vol% enflurane, and 2.3 +/- 0.1 vol% isoflurane in a randomized sequence. For hemorrhagic hypotension, blood was withdrawn gradually until a mean arterial pressure of 50 mm Hg was attained. Volatile anesthetics and hemorrhage reduced cardiac output, and hepatic arterial, portal venous, and total hepatic blood flows by comparable degrees. Mean hepatic PSO2 decreased significantly from 30.7 +/- 2.6 mm Hg at control to 17.4 +/- 2 and 17.5 +/- 2 mm Hg during enflurane and isoflurane (each P less than 0.05) anesthesia, respectively. The decrease to 11.5 +/- 2.5 mm Hg was more pronounced during halothane anesthesia. Hemorrhagic hypotension was associated with the lowest hepatic PSO2 (3.4 +/- 1.3 mm Hg) and the highest number of hypoxic (0-5 mm Hg 86%) and anoxic PSO2 values (0 mm Hg 46%). Pancreatic blood flow and oxygenation remained unchanged from control during halothane and enflurane administration, whereas isoflurane increased both variables. Hemorrhagic hypotension slightly reduced pancreatic flow (-8%) but significantly decreased PSO2 from 58 +/- 5 mm Hg at control to 36 +/- 3 mm Hg, with 7% of all measured values in the hypoxic range. Thus, volatile anesthetics preserved pancreatic but not hepatic

  10. Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances

    Directory of Open Access Journals (Sweden)

    Belić Branislava

    2011-01-01

    Full Text Available Background/Aim. Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS after completion of hyperbaric treatment. Methods. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA. Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Results. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p < 0.01. There was a negative correlation between the number of irreversiblly damaged red blood cells (ruptured at the 40th minute and neurological score in the studied animals (p < 0.05. Conclusion

  11. Impaired cerebral blood flow and oxygenation during exercise in type 2 diabetic patients

    DEFF Research Database (Denmark)

    Kim, Yu-Sok; Seifert, Thomas; Brassard, Patrice

    2015-01-01

    Endothelial vascular function and capacity to increase cardiac output during exercise are impaired in patients with type 2 diabetes (T2DM). We tested the hypothesis that the increase in cerebral blood flow (CBF) during exercise is also blunted and, therefore, that cerebral oxygenation becomes...... affected and perceived exertion increased in T2DM patients. We quantified cerebrovascular besides systemic hemodynamic responses to incremental ergometer cycling exercise in eight male T2DM and seven control subjects. CBF was assessed from the Fick equation and by transcranial Doppler-determined middle...... at higher workloads in T2DM patients and their work capacity and increase in cardiac output were only ~80% of that established in the control subjects. CBF and cerebral oxygenation were reduced during exercise in T2DM patients (P

  12. Influence of partial pressure of oxygen in blood samples on measurement performance in glucose-oxidase-based systems for self-monitoring of blood glucose.

    Science.gov (United States)

    Baumstark, Annette; Schmid, Christina; Pleus, Stefan; Haug, Cornelia; Freckmann, Guido

    2013-11-01

    Partial pressure of oxygen (pO2) in blood samples can affect blood glucose (BG) measurements, particularly in systems that employ the glucose oxidase (GOx) enzyme reaction on test strips. In this study, we assessed the impact of different pO2 values on the performance of five GOx systems and one glucose dehydrogenase (GDH) system. Two of the GOx systems are labeled by the manufacturers to be sensitive to increased blood oxygen content, while the other three GOx systems are not. Aliquots of 20 venous samples were adjusted to the following pO2 values: oxygen sensitive. © 2013 Diabetes Technology Society.

  13. Survival and function of phagocytes in blood culture media

    DEFF Research Database (Denmark)

    Fischer, T K; Prag, J; Kharazmi, A

    1999-01-01

    The survival and function of human phagocytes in sterile aerobic and anaerobic blood culture media were investigated using neutrophil morphology, white blood cell count in a haemoanalyser, flow cytometry, oxidative burst response, and bactericidal effect in Colorbact and Septi-Chek blood culture...... media and Bact/Alert. When comparing agitation to stationary incubation no difference in phagocytic activity was found. The methods showed the same trends demonstrating that the phagocytes' viability and activity were prolonged by oxygen and shortened by anaerobic conditions and sodium polyethanol...... sulfonate (SPS). Best preserved activity and viability were found in the aerobic media containing less than 0.5 g/l SPS, in which significant phagocyte oxidative burst and bactericidal activity were found up to 4 days after inoculation. Considering that the majority of bacteremias are due to aerobic...

  14. Comparison of extracapillary and endocapillary blood flow oxygenators for open heart surgery in dogs: efficiency of gas exchange and platelet conservation.

    Science.gov (United States)

    Hoshi, Katsuichiro; Tanaka, Ryou; Shibazaki, Akira; Nagashima, Yukiko; Hirao, Hidehiro; Namiki, Ryosuke; Takashima, Kazuaki; Noishiki, Yasuharu; Yamane, Yoshihisa

    2003-03-01

    The goal of the current study was to compare the efficiency of gas exchange and platelet conservation of a new extracapillary blood flow oxygenator versus an endocapillary blood flow oxygenator during open heart surgery with extracorporeal circulation in dogs. Dilation and remodeling of the right ventricular outflow tract of dogs was performed using a patch graft technique to simulate pulmonary stenosis. Sequential pre- and post-operative blood analysis revealed that gas exchange efficiency and platelet conservation was significantly greater with the extracapillary blood flow oxygenator than with the endocapillary blood flow oxygenator. However, the priming volume of the extracapillary blood flow oxygenator was significantly greater, leading to hemodilution. We conclude that while the extracapillary blood flow oxygenator provided benefits in terms of gas exchange and platelet conservation, development of a smaller extracapillary blood flow type oxygenator to reduce hemodilution effects would be beneficial.

  15. Oxygen tension level and human viral infections

    Energy Technology Data Exchange (ETDEWEB)

    Morinet, Frédéric, E-mail: frederic.morinet@sls.aphp.fr [Centre des Innovations Thérapeutiques en Oncologie et Hématologie (CITOH), CHU Saint-Louis, Paris (France); Université Denis Diderot, Sorbonne Paris Cité Paris, Paris (France); Casetti, Luana [Institut Cochin INSERM U1016, Paris (France); François, Jean-Hugues; Capron, Claude [Institut Cochin INSERM U1016, Paris (France); Laboratoire d' Hématologie, Hôpital Ambroise Paré, Boulogne (France); Université de Versailles Saint-Quentin en Yvelynes, Versailles (France); Pillet, Sylvie [Laboratoire de Bactériologie-Virologie-Hygiène, CHU de Saint-Etienne, Saint-Etienne (France); Université de Lyon et Université de Saint-Etienne, Jean Monnet, GIMAP EA3064, F-42023 Saint-Etienne, Lyon (France)

    2013-09-15

    The role of oxygen tension level is a well-known phenomenon that has been studied in oncology and radiotherapy since about 60 years. Oxygen tension may inhibit or stimulate propagation of viruses in vitro as well as in vivo. In turn modulating oxygen metabolism may constitute a novel approach to treat viral infections as an adjuvant therapy. The major transcription factor which regulates oxygen tension level is hypoxia-inducible factor-1 alpha (HIF-1α). Down-regulating the expression of HIF-1α is a possible method in the treatment of chronic viral infection such as human immunodeficiency virus infection, chronic hepatitis B and C viral infections and Kaposi sarcoma in addition to classic chemotherapy. The aim of this review is to supply an updating concerning the influence of oxygen tension level in human viral infections and to evoke possible new therapeutic strategies regarding this environmental condition. - Highlights: • Oxygen tension level regulates viral replication in vitro and possibly in vivo. • Hypoxia-inducible factor 1 (HIF-1α) is the principal factor involved in Oxygen tension level. • HIF-1α upregulates gene expression for example of HIV, JC and Kaposi sarcoma viruses. • In addition to classical chemotherapy inhibition of HIF-1α may constitute a new track to treat human viral infections.

  16. The neural network involved in a bimanual tactile-tactile matching discrimination task: a functional imaging study at 3 T

    Energy Technology Data Exchange (ETDEWEB)

    Habas, Christophe; Cabanis, Emmanuel A. [UPMC Paris 6, Service de NeuroImagerie, Hopital des Quinze-Vingts, Paris (France)

    2007-08-15

    The cerebral and cerebellar network involved in a bimanual object recognition was studied in blood oxygenation dependent level functional magnetic resonance imaging (fMRI). Nine healthy right-handed volunteers were scanned (1) while performing bilateral finger movements (nondiscrimination motor task), and (2) while performing a bimanual tactile-tactile matching discrimination task using small chess pieces (tactile discrimination task). Extensive activations were specifically observed in the parietal (SII, superior lateral lobule), insular, prefrontal, cingulate and neocerebellar cortices (HVIII), with a left predominance in motor areas, during the tactile discrimination task in contrast to the findings during the nondiscrimination motor task. Bimanual tactile-tactile matching discrimination recruits multiple sensorimotor and associative cerebral and neocerebellar networks (including the cerebellar second homunculus, HVIII), comparable to the neural circuits involved in unimanual tactile object recognition. (orig.)

  17. Functional MRI of the visual cortex and visual testing in patients with previous optic neuritis

    DEFF Research Database (Denmark)

    Langkilde, Annika Reynberg; Frederiksen, J.L.; Rostrup, Egill

    2002-01-01

    of the activated area and the signal change following ON, and compared the results with results of neuroophthalmological testing. We studied nine patients with previous acute ON and 10 healthy persons served as controls using fMRI with visual stimulation. In addition to a reduced activated volume, patients showed...... a reduced blood oxygenation level dependent (BOLD) signal increase and a greater asymmetry in the visual cortex, compared with controls. The volume of visual cortical activation was significantly correlated to the result of the contrast sensitivity test. The BOLD signal increase correlated significantly......The volume of cortical activation as detected by functional magnetic resonance imaging (fMRI) in the visual cortex has previously been shown to be reduced following optic neuritis (ON). In order to understand the cause of this change, we studied the cortical activation, both the size...

  18. MR vascular fingerprinting: A new approach to compute cerebral blood volume, mean vessel radius, and oxygenation maps in the human brain.

    Science.gov (United States)

    Christen, T; Pannetier, N A; Ni, W W; Qiu, D; Moseley, M E; Schuff, N; Zaharchuk, G

    2014-04-01

    In the present study, we describe a fingerprinting approach to analyze the time evolution of the MR signal and retrieve quantitative information about the microvascular network. We used a Gradient Echo Sampling of the Free Induction Decay and Spin Echo (GESFIDE) sequence and defined a fingerprint as the ratio of signals acquired pre- and post-injection of an iron-based contrast agent. We then simulated the same experiment with an advanced numerical tool that takes a virtual voxel containing blood vessels as input, then computes microscopic magnetic fields and water diffusion effects, and eventually derives the expected MR signal evolution. The parameter inputs of the simulations (cerebral blood volume [CBV], mean vessel radius [R], and blood oxygen saturation [SO2]) were varied to obtain a dictionary of all possible signal evolutions. The best fit between the observed fingerprint and the dictionary was then determined by using least square minimization. This approach was evaluated in 5 normal subjects and the results were compared to those obtained by using more conventional MR methods, steady-state contrast imaging for CBV and R and a global measure of oxygenation obtained from the superior sagittal sinus for SO2. The fingerprinting method enabled the creation of high-resolution parametric maps of the microvascular network showing expected contrast and fine details. Numerical values in gray matter (CBV=3.1±0.7%, R=12.6±2.4μm, SO2=59.5±4.7%) are consistent with literature reports and correlated with conventional MR approaches. SO2 values in white matter (53.0±4.0%) were slightly lower than expected. Numerous improvements can easily be made and the method should be useful to study brain pathologies. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Coverage-dependent adsorption thermodynamics of oxygen on ZnO(0001)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ming; Seebauer, Edmund G., E-mail: eseebaue@illinois.edu

    2017-03-01

    Highlights: • Adsorption enthalpy and entropy of oxygen on Zn-term ZnO(0001) were measured by photoreflectance. • These parameters are large in magnitude and vary nonmonotonically with coverage. • Many kinds of sites, chemical species and reconstructions contribute to this behavior. • Entropic and enthalpic contributions to the free energy are comparable near room temperature. - Abstract: The equilibrium behavior of oxygen adsorbed on metal oxide surfaces such as ZnO(0001) often affects their behavior in applications such as gas sensing. The present work attempts to bridge this distinct gap to applications from an alternate perspective by employing the optical technique of photoreflectance (PR) to measure the enthalpy ΔH{sub ads} and entropy ΔS{sub ads} of oxygen adsorption as a function of coverage on Zn-terminated ZnO(0001). The large and strongly coverage-dependent parameters, stemming from a multiplicity of sites, chemical species and reconstructions, lead to a nonmonotonic coverage variation in both ΔH{sub ads} and ΔS{sub ads}. The entropic contribution to the free energy is comparable to the enthalpic contribution even near room temperature, so that temperature effects on oxygen adsorption may be uncommonly large.

  20. Susceptibility contrast imaging of CO2-induced changes in the blood volume of the human brain

    DEFF Research Database (Denmark)

    Rostrup, Egill; Larsson, H B; Toft, P B

    1996-01-01

    PURPOSE: To investigate changes in the regional cerebral blood volume (rCBV) in human subjects during rest and hypercapnia by MR imaging, and to compare the results from contrast-enhanced and noncontrast-enhanced susceptibility-weighted imaging. MATERIAL AND METHODS: Five healthy volunteers (aged...... to be in accordance with results obtained by other methods. Noncontrast functional MR (fMR) imaging showed signal increases in gray matter, but also inconsistent changes in some white matter regions. CONCLUSION: In this experiment, contrast-enhanced imaging seemed to show a somewhat higher sensitivity towards changes...

  1. Dual-wavelength photothermal optical coherence tomography for blood oxygen saturation measurement

    Science.gov (United States)

    Yin, Biwei; Kuranov, Roman V.; McElroy, Austin B.; Milner, Thomas E.

    2013-03-01

    We report design and demonstration of a dual wavelength photothermal (DWP) optical coherence tomography (OCT) system for imaging of a phantom microvessel and measurement of hemoglobin oxygen saturation (SO2) level. The DWP-OCT system contains a swept-source (SS) two-beam phase-sensitive (PhS) OCT system (1060 nm) and two intensity modulated photothermal excitation lasers (770 nm and 800 nm). The PhS-OCT probe beam (1060 nm) and photothermal excitation beams are combined into one single-mode optical fiber. A galvanometer based two-dimensional achromatic scanning system is designed to provide 14 μm lateral resolution for the PhS-OCT probe beam (1060 nm) and 13 μm lateral resolution for photothermal excitation beams. DWP-OCT system's sensitivity is 102 dB, axial resolution is 13 μm in tissue and uses a real-time digital dispersion compensation algorithm. Noise floor for optical pathlength measurements is 300 pm in the signal frequency range (380-400 Hz) of photothermal modulation frequencies. Blood SO2 level is calculated from measured optical pathlength (op) signal in a 300 μm diameter microvessel phantom introduced by the two photothermal excitation beams. En-face and B-scan images of a phantom microvessel are recorded, and six blood samples' SO2 levels are measured using DWP-OCT and compared with values provided by a commercial blood oximeter. A mathematical model indicates thermal diffusion introduces a systematic artifact that over-estimates SO2 values and is consistent with measured data.

  2. Restoration of the contrast of cerebral blood flows by the spatial deconvolution method

    International Nuclear Information System (INIS)

    Compingt, D.L.; Philippon, B.L.

    1982-01-01

    The measurement of regional cerebral blood flows (rCBF) with a gamma camera during xenon-133 inhalation necessitates collimators with high efficiency. Their spatial resolutions are weak: on the images given by a F.W.H.M. collimator (25 mm to 5 cm depth of water), the contrast restoration method by the ponctual dispersion function (P.D.F.) is used. The convolution product (Image)=(Object)*(P.D.F.) is resolved by a bidimensional Fast Fourier Transform treatment. The high frequencies are eliminated by a progressive filtration. The rCBF is calculated with Obrist's method. The Initial Slope Index is only used. A rCBF image with the calculator is also realized. The numerical values are compared with the normal treatment (N) without contrast restoration and after restoration. 22 patients are so treated after severe cerebral strokes. The hemispheric average of the flows according to the 2 treatments is unchanged (difference: 1.1%). The contrast between higher and lower flow areas is increasing by 73% after contrast restoration (significant difference: p [fr

  3. Change in the work function of zirconium by oxidation at high temperatures and low oxygen pressures

    International Nuclear Information System (INIS)

    Maeno, Yutaka; Yamamoto, Masahiro; Naito, Shizuo; Mabuchi, Mahito; Hashino, Tomoyasu

    1991-01-01

    Changes in the work function of zirconium on oxidation are measured at oxygen pressures of 3.0 x 10 -6 - 3.0 x 10 -4 Pa and at temperatures in the range 426-775 K. The work function first decreases then increases until a final saturation stage is reached. Use of secondary-ion mass spectroscopy (SIMS) shows that the changes correspond to oxygen adsorption, oxide nucleation and oxide growth, respectively. The initial decrease in work function is interpreted by the incorporation of oxygen adatoms into the subsurface. The oxygen adsorption potential of zirconium is evaluated by an effective medium theory, and the physical origin of the incorporation of oxygen adatoms is discussed. The positive change in the work function caused by oxide formation and the temperature and pressure dependences of the change in the work function by oxidation are explained qualitatively. (author)

  4. Neurotoxicity of iodinated radiological contrast media

    International Nuclear Information System (INIS)

    Araujo Pinheiro, R.S. de

    1988-01-01

    We studied during the last ten years the neurotoxicity of artificial iodinated contrast media, with prospective clinical and experimental protocols. The experimental investigation in animals aimed to understand the relationship between the intracarotid injection, the subarachnoid application and the integrity of the blood-brain barrier function. The electro physiologic disturbances and the morphologic observation of pial circulation support the evidence that iodinated artificial contrast media induces significant alterations in brain metabolism and in the autoregulation of the blood flow of the encephalon. Even if many of such phenomena may not be apparent at the clinical level, we supposed that they are always present and that their clinical exteriorization is prevented by the immediate and effective action of homeostatic mechanisms. (author)

  5. Reduction of blood oxygen levels enhances postprandial cardiac hypertrophy in Burmese python (Python bivittatus).

    Science.gov (United States)

    Slay, Christopher E; Enok, Sanne; Hicks, James W; Wang, Tobias

    2014-05-15

    Physiological cardiac hypertrophy is characterized by reversible enlargement of cardiomyocytes and changes in chamber architecture, which increase stroke volume and via augmented convective oxygen transport. Cardiac hypertrophy is known to occur in response to repeated elevations of O2 demand and/or reduced O2 supply in several species of vertebrate ectotherms, including postprandial Burmese pythons (Python bivittatus). Recent data suggest postprandial cardiac hypertrophy in P. bivittatus is a facultative rather than obligatory response to digestion, though the triggers of this response are unknown. Here, we hypothesized that an O2 supply-demand mismatch stimulates postprandial cardiac enlargement in Burmese pythons. To test this hypothesis, we rendered animals anemic prior to feeding, essentially halving blood oxygen content during the postprandial period. Fed anemic animals had heart rates 126% higher than those of fasted controls, which, coupled with a 71% increase in mean arterial pressure, suggests fed anemic animals were experiencing significantly elevated cardiac work. We found significant cardiac hypertrophy in fed anemic animals, which exhibited ventricles 39% larger than those of fasted controls and 28% larger than in fed controls. These findings support our hypothesis that those animals with a greater magnitude of O2 supply-demand mismatch exhibit the largest hearts. The 'low O2 signal' stimulating postprandial cardiac hypertrophy is likely mediated by elevated ventricular wall stress associated with postprandial hemodynamics. © 2014. Published by The Company of Biologists Ltd.

  6. Hemoglobin as a factor in the control of tumor oxygenation

    International Nuclear Information System (INIS)

    Hirst, D.G.

    1987-01-01

    The concentration of hemoglobin in the blood has been shown to have a market effect on the radiosensitivity of human and animal tumors. Experimental studies in mice indicate that radiosensitivity is influenced by a change in the hemoglobin level rather than by the absolute concentration. This dependence may be exploited to therapeutic advantage. Recent studies of hemoglobin/oxygen affinity have shown that the concentration of 2,3 diphosphoglycerate (2,3 DPG) affects tumor sensitivity to X-rays. Increased 2,3 DPG levels increase radiosensitivity in several mouse tumors. The time dependence of this effect remains to be established. The effective application of these effects in man may depend on the development of drugs which produce changes in hemoglobin affinity without the need for blood transfusions. Several drugs are currently being investigated

  7. Dependence of the subharmonic signal from contrast agent microbubbles on ambient pressure: A theoretical analysis.

    Science.gov (United States)

    Jiménez-Fernández, J

    2018-01-01

    This paper investigates the dependence of the subharmonic response in a signal scattered by contrast agent microbubbles on ambient pressure to provide quantitative estimations of local blood pressure. The problem is formulated by assuming a gas bubble encapsulated by a shell of finite thickness with dynamic behavior modeled by a nonlinear viscoelastic constitutive equation. For ambient overpressure compatible with the clinical range, the acoustic pressure intervals where the subharmonic signal may be detected (above the threshold for the onset and below the limit value for the first chaotic transition) are determined. The analysis shows that as the overpressure is increased, all harmonic components are displaced to higher frequencies. This displacement is significant for the subharmonic of order 1/2 and explains the increase or decrease in the subharmonic amplitude with ambient pressure described in previous works. Thus, some questions related to the monotonic dependence of the subharmonic amplitude on ambient pressure are clarified. For different acoustic pressures, quantitative conditions for determining the intervals where the subharmonic amplitude is a monotonic or non-monotonic function of the ambient pressure are provided. Finally, the influence of the ambient pressure on the subharmonic resonance frequency is analyzed.

  8. Evolution of factors affecting placental oxygen transfer

    DEFF Research Database (Denmark)

    Carter, A M

    2009-01-01

    A review is given of the factors determining placental oxygen transfer and the oxygen supply to the fetus. In the case of continuous variables, such as the rate of placental blood flow, it is not possible to trace evolutionary trends. Discontinuous variables, for which we can define character sta......, where fetal and adult haemoglobin are not different, developmental regulation of 2, 3-diphosphoglycerate ensures the high oxygen affinity of fetal blood. Oxygen diffusing capacity is dependent on diffusion distance, which may vary with the type of interhaemal barrier. It has been shown...

  9. Effects of iodinated contrast media on blood and endothelium

    International Nuclear Information System (INIS)

    Aspelin, Peter; Stacul, Fulvio; Thomsen, Henrik S.; Morcos, Sameh K.; Molen, Aart J. van der

    2006-01-01

    The aim of the study was to assess the effects of iodinated contrast media on blood components and endothelium based on experimental and clinical studies and to produce clinically relevant guidelines for reducing thrombotic and hematologic complications following the intravascular use of contrast media. A report was drafted after review of the literature and discussions among the members of the Contrast Media Safety Committee of the European Society of Urogenital Radiology. The final report was produced following discussion at the 12th European Symposium on Urogenital Radiology in Ljubljana, Slovenia (2005). Experimental data indicate that all iodinated contrast media produce an anticoagulant effect and that this effect is greater with ionic contrast media. Several of the in vitro and experimental in vivo studies on haematological effects of contrast media have not been confirmed by clinical studies. Low- or iso-osmolar contrast media should be used for diagnostic and interventional angiographic procedures, including phlebography. Meticulous angiographic technique is the most important factor for reducing the thrombotic complications associated with angiographic procedures. Drugs and interventional devices that decrease the risk of thromboembolic complications during interventional procedures minimize the importance of the effects of contrast media. (orig.)

  10. Effects of iodinated contrast media on blood and endothelium

    Energy Technology Data Exchange (ETDEWEB)

    Aspelin, Peter [Karolinska Institute/Huddinge University Hospital, Division of Radiology, Centre for Surgical Sciences, Stockholm (Sweden); Stacul, Fulvio [Institute of Radiology, Trieste (Italy); Thomsen, Henrik S. [Copenhagen University Hospital at Herlev, Department of Diagnostic Radiology 54E2, Herlev (Denmark); Morcos, Sameh K. [Sheffield Teaching Hospitals NHS Trust, Department of Diagnostic Imaging, Northern General Hospital, Sheffield (United Kingdom); Molen, Aart J. van der [Leiden University Medical Centre, Department of Radiology, Leiden (Netherlands)

    2006-05-15

    The aim of the study was to assess the effects of iodinated contrast media on blood components and endothelium based on experimental and clinical studies and to produce clinically relevant guidelines for reducing thrombotic and hematologic complications following the intravascular use of contrast media. A report was drafted after review of the literature and discussions among the members of the Contrast Media Safety Committee of the European Society of Urogenital Radiology. The final report was produced following discussion at the 12th European Symposium on Urogenital Radiology in Ljubljana, Slovenia (2005). Experimental data indicate that all iodinated contrast media produce an anticoagulant effect and that this effect is greater with ionic contrast media. Several of the in vitro and experimental in vivo studies on haematological effects of contrast media have not been confirmed by clinical studies. Low- or iso-osmolar contrast media should be used for diagnostic and interventional angiographic procedures, including phlebography. Meticulous angiographic technique is the most important factor for reducing the thrombotic complications associated with angiographic procedures. Drugs and interventional devices that decrease the risk of thromboembolic complications during interventional procedures minimize the importance of the effects of contrast media. (orig.)

  11. Transverse water relaxation in whole blood and erythrocytes at 3T, 7T, 9.4T, 11.7T and 16.4T; determination of intracellular hemoglobin and extracellular albumin relaxivities.

    Science.gov (United States)

    Grgac, Ksenija; Li, Wenbo; Huang, Alan; Qin, Qin; van Zijl, Peter C M

    2017-05-01

    Blood is a physiological substance with multiple water compartments, which contain water-binding proteins such as hemoglobin in erythrocytes and albumin in plasma. Knowing the water transverse (R 2 ) relaxation rates from these different blood compartments is a prerequisite for quantifying the blood oxygenation level-dependent (BOLD) effect. Here, we report the Carr-Purcell-Meiboom-Gill (CPMG) based transverse (R 2CPMG ) relaxation rates of water in bovine blood samples circulated in a perfusion system at physiological temperature in order to mimic blood perfusion in humans. R 2CPMG values of blood plasma, lysed packed erythrocytes, lysed plasma/erythrocyte mixtures, and whole blood at 3 T, 7 T, 9.4 T, 11.7 T and 16.4 T were measured as a function of hematocrit or hemoglobin concentration, oxygenation, and CPMG inter-echo spacing (τ cp ). R 2CPMG in lysed cells showed a small τ cp dependence, attributed to the water exchange rate between free and hemoglobin-bound water to be much faster than τ cp . This was contrary to the tangential dependence in whole blood, where a much slower exchange between cells and blood plasma applies. Whole blood data were fitted as a function of τ cp using a general tangential correlation time model applicable for exchange as well as diffusion contributions to R 2CPMG , and the intercept R 20blood at infinitely short τ cp was determined. The R 20blood values at different hematocrit and the R 2CPMG values of lysed erythrocyte/plasma mixtures at different hemoglobin concentration were used to determine the relaxivity of hemoglobin inside the erythrocyte (r 2Hb ) and albumin (r 2Alb ) in plasma. The r 2Hb values obtained from lysed erythrocytes and whole blood were comparable at full oxygenation. However, while r 2Hb determined from lysed cells showed a linear dependence on oxygenation, this dependence became quadratic in whole blood. This possibly suggests an additional relaxation effect inside intact cells, perhaps due to hemoglobin

  12. The effects of capillary transit time heterogeneity (CTH on the cerebral uptake of glucose and glucose analogs:Application to FDG and comparison to oxygen uptake.

    Directory of Open Access Journals (Sweden)

    Hugo Angleys

    2016-10-01

    Full Text Available Glucose is the brain’s principal source of ATP, but the extent to which cerebral glucose consumption (CMRglc is coupled with its oxygen consumption (CMRO2 remains unclear. Measurements of the brain’s oxygen-glucose index OGI=CMRO2/CMRglc suggest that its oxygen uptake largely suffices for oxidative phosphorylation. Nevertheless, during functional activation and in some disease states, brain tissue seemingly produces lactate although cerebral blood flow (CBF delivers sufficient oxygen, so-called aerobic glycolysis. OGI measurements, in turn, are method-dependent in that estimates based on glucose analog uptake depend on the so-called lumped constant (LC to arrive at CMRglc. Capillary transit time heterogeneity (CTH, which is believed to change during functional activation and some disease states, affects the extraction efficacy of oxygen from blood. We developed a three-compartment model of glucose extraction to examine whether CTH also affects glucose extraction into brain tissue. We then combined this model with our previous model of oxygen extraction to examine whether differential glucose and oxygen extraction might favor nonoxidative glucose metabolism under certain conditions. Our model predicts that glucose uptake is largely unaffected by changes in its plasma concentration, while changes in CBF and CTH affect glucose and oxygen uptake to different extents. Accordingly, functional hyperemia facilitates glucose uptake more than oxygen uptake, favoring aerobic glycolysis during enhanced energy demands. Applying our model to glucose analogs, we observe that LC depends on physiological state, with a risk of overestimating relative increases in CMRglc during functional activation by as much as 50%.

  13. Early disrupted neurovascular coupling and changed event level hemodynamic response function in type 2 diabetes: an fMRI study.

    Science.gov (United States)

    Duarte, João V; Pereira, João M S; Quendera, Bruno; Raimundo, Miguel; Moreno, Carolina; Gomes, Leonor; Carrilho, Francisco; Castelo-Branco, Miguel

    2015-10-01

    Type 2 diabetes (T2DM) patients develop vascular complications and have increased risk for neurophysiological impairment. Vascular pathophysiology may alter the blood flow regulation in cerebral microvasculature, affecting neurovascular coupling. Reduced fMRI signal can result from decreased neuronal activation or disrupted neurovascular coupling. The uncertainty about pathophysiological mechanisms (neurodegenerative, vascular, or both) underlying brain function impairments remains. In this cross-sectional study, we investigated if the hemodynamic response function (HRF) in lesion-free brains of patients is altered by measuring BOLD (Blood Oxygenation Level-Dependent) response to visual motion stimuli. We used a standard block design to examine the BOLD response and an event-related deconvolution approach. Importantly, the latter allowed for the first time to directly extract the true shape of HRF without any assumption and probe neurovascular coupling, using performance-matched stimuli. We discovered a change in HRF in early stages of diabetes. T2DM patients show significantly different fMRI response profiles. Our visual paradigm therefore demonstrated impaired neurovascular coupling in intact brain tissue. This implies that functional studies in T2DM require the definition of HRF, only achievable with deconvolution in event-related experiments. Further investigation of the mechanisms underlying impaired neurovascular coupling is needed to understand and potentially prevent the progression of brain function decrements in diabetes.

  14. Differences in prefrontal blood oxygenation during an acute multitasking stressor in ecstasy polydrug users.

    Science.gov (United States)

    Roberts, C A; Wetherell, M A; Fisk, J E; Montgomery, C

    2015-01-01

    Cognitive deficits are well documented in ecstasy (3,4-methylenedioxymethamphetamine; MDMA) users, with such deficits being taken as evidence of dysregulation of the serotonin (5-hydroxytryptamine; 5-HT) system. More recently neuroimaging has been used to corroborate these deficits. The present study aimed to assess multitasking performance in ecstasy polydrug users, polydrug users and drug-naive individuals. It was predicted that ecstasy polydrug users would perform worse than non-users on the behavioural measure and this would be supported by differences in cortical blood oxygenation. In the study, 20 ecstasy-polydrug users, 17 polydrug users and 19 drug-naive individuals took part. On day 1, drug use history was taken and questionnaire measures were completed. On day 2, participants completed a 20-min multitasking stressor while brain blood oxygenation was measured using functional near infrared spectroscopy (fNIRS). There were no significant differences between the three groups on the subscales of the multitasking stressor. In addition, there were no significant differences on self-report measures of perceived workload (NASA Task Load Index). In terms of mood, ecstasy users were significantly less calm and less relaxed compared with drug-naive controls. There were also significant differences at three voxels on the fNIRS, indicating decreased blood oxygenation in ecstasy users compared with drug-naive controls at voxel 2 (left dorsolateral prefrontal cortex), voxel 14 and voxel 16 (right dorsolateral prefrontal cortex), and compared with polydrug controls at V14. The results of the present study provide support for changes in brain activation during performance of demanding tasks in ecstasy polydrug users, which could be related to cerebral vasoconstriction.

  15. The effects of altitude/hypoxic training on oxygen delivery capacity of the blood and aerobic exercise capacity in elite athletes - a meta-analysis.

    Science.gov (United States)

    Park, Hun-Young; Hwang, Hyejung; Park, Jonghoon; Lee, Seongno; Lim, Kiwon

    2016-03-31

    This study was designed as a meta-analysis of randomized controlled trials comparing effectiveness of altitude/hypoxic training (experimental) versus sea-level training (control) on oxygen delivery capacity of the blood and aerobic exercise capacity of elite athletes in Korea. Databases (Research Information Service System, Korean studies Information Service System, National Assembly Library) were for randomized controlled trials comparing altitude/hypoxic training versus sea-level training in elite athletes. Studies published in Korea up to December 2015 were eligible for inclusion. Oxygen delivery capacity of the blood was quantified by red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), erythropoietin (EPO); and aerobic exercise capacity was quantified by maximal oxygen consumption (VO2max). RBC, Hb, Hct, VO2max represented heterogeneity and compared post-intervention between altitude/hypoxic training and sea-level training in elite athletes by a random effect model meta-analysis. EPO represented homogeneity and meta-analysis performed by a fixed effect model. Eight independent studies with 156 elite athletes (experimental: n = 82, control: n = 74) were included in the metaanalysis. RBC (4.499×10(5) cell/ul, 95 % CI: 2.469 to 6.529), Hb (5.447 g/dl, 95 % CI: 3.028 to 7.866), Hct (3.639 %, 95 % CI: 1.687 to 5.591), EPO (0.711 mU/mL, 95% CI: 0.282 to 1.140), VO2max (1.637 ml/kg/min, 95% CI: 0.599 to 1.400) showed significantly greater increase following altitude/hypoxic training, as compared with sea-level training. For elite athletes in Korea, altitude/ hypoxic training appears more effective than sea-level training for improvement of oxygen delivery capacity of the blood and aerobic exercise capacity.

  16. Inhibition of fungal growth with extreme low oxygen levels

    DEFF Research Database (Denmark)

    Nielsen, Per Væggemose; Haasum, Iben

    1998-01-01

    Fungal spoilage of foods is effectively controlled by removal of oxygen from the package, especially if this is combined with elevated carbon dioxide (CO2) levels. However, great uncertainty exist on just how low the residual oxygen levels in the package must be especially when carbon dioxide lev...... food with low CO2 levels. Active packaging with oxygen absorbers may be considered for these products. The packaging solution must also reflect the micro flora of the product.......Fungal spoilage of foods is effectively controlled by removal of oxygen from the package, especially if this is combined with elevated carbon dioxide (CO2) levels. However, great uncertainty exist on just how low the residual oxygen levels in the package must be especially when carbon dioxide...... Penicillia and Aspergilli were also inhibited by oxygen levels less than 0.5%, but less than 0.01% was required to efficiently inhibit these fungi. Most resistant to very low oxygen levels was the Fusarium species.These results shows that very low oxygen levels are required to avoid fungal growth in package...

  17. Effects of snake venom from Saudi cobras and vipers on hormonal levels in peripheral blood.

    Science.gov (United States)

    Abdel-Galil, Khidir A; Al-Hazimi, Awdah M

    2004-08-01

    Knowledge about the effects of snake venoms on endocrine glands in the Kingdom of Saudi Arabia (KSA) is meager. The aim of the present study is to investigate the acute and chronic envenomation from 4 snakes out of 8 species of Saudi Cobras and Vipers on the tissues of endocrine glands and peripheral hormonal levels in male rats. The peripheral blood levels of 4 hormones mainly testosterone, cortisol, insulin and thyroxin were investigated in male Wistar rats following acute and chronic treatment of the rats with poisonous snake venoms at the Department of Physiology, Faculty of Medicine, King Abdul-Aziz University, Jeddah, Kingdom of Saudi Arabia between September 2000 to May 2001. Using radio immunoassay for hormonal analysis, a rise in testosterone levels in peripheral blood was obtained following acute treatment, which is due to the effect of the venoms on vascular permeability and increased blood flow. In contrast, the chronic treatment with venoms resulted in a delayed effect on vascular permeability and testicular degeneration resulting in a decreased blood flow and a significant drop in testosterone concentration. Cortisol levels were no different from the controls during acute treatment but it demonstrates gradual rise following chronic treatment to withstand the stress imposed on the animals. Similar results were obtained for insulin, which showed normal values with acute treatment but decreased levels of chronic treatment suggesting insulin insufficiently. Likewise, the thyroxin levels were decreased with chronic treatment suggesting a toxic effect of the poison on the rich blood supply of the thyroid follicles with a subsequent decrease in blood flow to the tissues and therefore, decreased thyroid hormone levels. The effects of venom toxicity on testosterone levels were either normal or stimulatory with acute treatment or inhibitory with chronic treatment depending on the vascular blood flow and testicular degeneration. Cortisol levels were normal at

  18. [Impact of oxygen toxic action on the erythrocyte membrane and possibility of estimating central nervous system function disturbances].

    Science.gov (United States)

    Belić, Branislava; Cincović, Marko R

    2011-07-01

    BACKGROUND/AIM; Prolonged exposure to hyperbaric oxygen leads to changes of erythrocytes shape as a consequence of toxic effects of oxygen on the erythrocyte membrane. The aim of this study was to examine the association between occurance of pathological forms of erythrocytes at different time from the start of hyperbaric oxygenation and the moment of convulsions occurrence, an interrelationship of different pathological forms of erythrocytes during exposure to hyperbaric oxygenation, as well as the correlation between the presence of ruptured erythrocytes and function of central nervous system (CNS) after completion of hyperbaric treatment. Sixty laboratory mice, Mus musculus, were exposed to the wholly-oxygen pressure of 3.5 absolute atmospheres (ATA). Blood was collected at the 32nd, 34th, 36th, 38th and 40th minutes after the exposure to oxygen. Pathological forms of erythrocytes were examined by electron microscopy. A moment of convulsions occurrence was registered in all animals. After decompression neurological examinations of experimental animals were perfomed. The Pearson's coefficient of correlation, and linear regression equations for the parameters outlined in the aim of the study were calculated. Hyperbaric oxygen caused damages of erythrocytes at the 34th minute after beginning of the treatment. Various forms of abnormal red blood cells occured, and immediately before the occurrence of irreversible changes (erythrocyte membrane rupture) echinocyte shape was dominated. A significant correlation between the number of damaged red blood cells at 34th minute and their number at the 36th, 38th and 40th minute was found. Convulsions were diagnosed significantly earlier in mice with a greater number of damaged red blood cells (p potential burden of CNS after cessation of hyperbaric oxygenation.

  19. Local cerebral blood flow and local oxygen consumption in prolonged hemiplegic migraine

    International Nuclear Information System (INIS)

    Baron, J.C.; Lebrun-Grandie, P.; Serdaru, M.; Bousser, M.G.; Lhermitte, F.; Cabanis, E.

    1982-09-01

    This work gives the results of a study by positron emission tomography of the cerebral blood flow (CBF), oxygen-extraction rate (O 2 E) and oxygen consumption (CMRO 2 ) during severe and prolonged attack of hemiplegic migraine. The salient facts observed are a high (CBF) in the brain hemisphere affected (ruling out the hypothesis of a persistent cerebral ischemia), together with a collapsed O 2 E (''luxury perfusion'') and especially preservation of the CMRO 2 suggesting a decoupling not only between CBF and CMRO 2 but also between CMRO 2 and functional state of the tissue. Some time after the attack a new study showed the recoupling between CBF and CMRO 2 , but with the latter reduced in the affected hemisphere although the clinical and tomodensitometric state had returned to normal. These new observations should not however be improperly generalised to all migraines, given the unusual characteristics of the disorder in our patient [fr

  20. Lung vital capacity and oxygen saturation in adults with cerebral palsy

    Directory of Open Access Journals (Sweden)

    Lampe R

    2014-12-01

    Full Text Available Renée Lampe,1,2 Tobias Blumenstein,2 Varvara Turova,2 Ana Alves-Pinto2 1Markus Würth Stiftungsprofessur, Technical University of Munich, Munich, Germany; 2Research Unit for Cerebral Palsy and Children Neuroorthopaedics of the Buhl-Strohmaier Foundation, Orthopedic Department of the Clinic “rechts der Isar” of the Technical University of Munich, Munich, Germany Background: Individuals with infantile cerebral palsy have multiple disabilities. The most conspicuous syndrome being investigated from many aspects is motor movement disorder with a spastic gait pattern. The lung function of adults with spasticity attracts less attention in the literature. This is surprising because decreased thoracic mobility and longstanding scoliosis should have an impact on lung function. With increasing age and the level of disability, individuals become susceptible to lung infections and reflux illness, and these are accompanied by increased aspiration risk. This study examined, with different methods, to what extent adults with congenital cerebral palsy and acquired spastic paresis – following traumatic brain injury – showed restriction of lung function. It also assessed the contribution of disability level on this restriction.Methods: The oxygen saturation of 46 adults with a diagnosis of cerebral palsy was measured with an oximeter. Lung vital capacity was measured with a mobile spirometer and excursion of the thorax was clinically registered. The gross motor function levels and the presence or absence of scoliosis were determined.Results: A significantly positive correlation between lung vital capacity and chest expansion was established. Both the lung vital capacity and the thorax excursion decreased with increases in gross motor function level. Oxygen saturation remained within the normal range in all persons, in spite of reduced values of the measured lung parameters. No statistically significant dependency between lung vital capacity and oxygen

  1. Pulsed near-infrared photoacoustic spectroscopy of blood

    Science.gov (United States)

    Laufer, Jan G.; Elwell, Clare E.; Delpy, Dave T.; Beard, Paul C.

    2004-07-01

    The aim of this study was to use pulsed near infrared photoacoustic spectroscopy to determine the oxygen saturation (SO2) of a saline suspension of red blood cells in vitro. The photoacoustic measurements were made in a cuvette which formed part of a larger circuit through which the red blood cell suspension was circulated. Oxygen saturation of the red blood cell suspension was altered between 2-3% to 100% in step increments using a membrane oxygenator and at each increment an independent measurement of oxygen saturation was made using a co-oximeter. An optical parametric oscillator laser system provided nanosecond excitation pulses at a number of wavelengths in the near-infrared spectrum (740-1040nm) which were incident on the cuvette. The resulting acoustic signals were detected using a broadband (15MHz) Fabry-Perot polymer film transducer. The optical transport coefficient and amplitude were determined from the acoustic signals as a function of wavelength. These data were then used to calculate the relative concentrations of oxy- and deoxyhaemoglobin, using their known specific absorption coefficients and an empirically determined wavelength dependence of optical scattering over the wavelength range investigated. From this, the oxygen saturation of the suspension was derived with an accuracy of +/-5% compared to the co-oximeter SO2 measurements.

  2. Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

    DEFF Research Database (Denmark)

    Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

    2012-01-01

    Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

  3. Alveolar gas exchange and tissue oxygenation during incremental treadmill exercise, and their associations with blood O2 carrying capacity

    Directory of Open Access Journals (Sweden)

    Antti-Pekka E. Rissanen

    2012-07-01

    Full Text Available The magnitude and timing of oxygenation responses in highly active leg muscle, less active arm muscle, and cerebral tissue, have not been studied with simultaneous alveolar gas exchange measurement during incremental treadmill exercise. Nor is it known, if blood O2 carrying capacity affects the tissue-specific oxygenation responses. Thus, we investigated alveolar gas exchange and tissue (m. vastus lateralis, m. biceps brachii, cerebral cortex oxygenation during incremental treadmill exercise until volitional fatigue, and their associations with blood O2 carrying capacity in 22 healthy men. Alveolar gas exchange was measured, and near-infrared spectroscopy (NIRS was used to monitor relative concentration changes in oxy- (Δ[O2Hb], deoxy- (Δ[HHb] and total hemoglobin (Δ[tHb], and tissue saturation index (TSI. NIRS inflection points (NIP, reflecting changes in tissue-specific oxygenation, were determined and their coincidence with ventilatory thresholds (anaerobic threshold (AT, respiratory compensation point (RC; V-slope method was examined. Blood O2 carrying capacity (total hemoglobin mass (tHb-mass was determined with the CO-rebreathing method. In all tissues, NIPs coincided with AT, whereas RC was followed by NIPs. High tHb-mass associated with leg muscle deoxygenation at peak exercise (e.g., Δ[HHb] from baseline walking to peak exercise vs. tHb-mass: r = 0.64, p < 0.01, but not with arm muscle- or cerebral deoxygenation. In conclusion, regional tissue oxygenation was characterized by inflection points, and tissue oxygenation in relation to alveolar gas exchange during incremental treadmill exercise resembled previous findings made during incremental cycling. It was also found out, that O2 delivery to less active m. biceps brachii may be limited by an accelerated increase in ventilation at high running intensities. In addition, high capacity for blood O2 carrying was associated with a high level of m. vastus lateralis deoxygenation at peak

  4. Monitoring Your Blood Sugar Level

    Science.gov (United States)

    ... and NutritionHealth Insurance: Understanding What It CoversHigh Homocysteine Level: How It Affects Your Blood VesselsUnderstanding Your Medical ... Health Resources Healthcare Management Monitoring Your Blood Sugar Level Monitoring Your Blood Sugar Level Share Print What ...

  5. The Choroidal Eye Oximeter - An instrument for measuring oxygen saturation of choroidal blood in vivo

    Science.gov (United States)

    Laing, R. A.; Danisch, L. A.; Young, L. R.

    1975-01-01

    The Choroidal Eye Oximeter is an electro-optical instrument that noninvasively measures the oxygen saturation of choroidal blood in the back of the human eye by a spectrophotometric method. Since choroidal blood is characteristic of blood which is supplied to the brain, the Choroidal Eye Oximeter can be used to monitor the amount of oxygen which is supplied to the brain under varying external conditions. The instrument consists of two basic systems: the optical system and the electronic system. The optical system produces a suitable bi-chromatic beam of light, reflects this beam from the fundus of the subject's eye, and onto a low-noise photodetector. The electronic system amplifies the weak composite signal from the photodetector, computes the average oxygen saturation from the area of the fundus that was sampled, and displays the value of the computed oxygen saturation on a panel meter.

  6. Oxygen-implanted induced formation of oxide layer enhances blood compatibility on titanium for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Hung, Wei-Chiang [School of Oral Hygiene, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University Hospital, Taipei 110, Taiwan (China); Chang, Fang-Mo [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Yang, Tzu-Sen [Master Program in Graduate Institute of Nanomedicine and Medical Engineering, Taipei Medical University, Taipei 110, Taiwan (China); Ou, Keng-Liang [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Research Center for Biomedical Implants and Microsurgery Devices, Taipei Medical University, Taipei 110, Taiwan (China); Department of Dentistry, Taipei Medical University-Shuang-Ho Hospital, Taipei 235, Taiwan (China); Lin, Che-Tong [School of Dentistry, Taipei Medical University, Taipei 110, Taiwan (China); Peng, Pei-Wen, E-mail: apon@tmu.edu.tw [School of Dental Technology, Taipei Medical University, Taipei 110, Taiwan (China)

    2016-11-01

    Titanium dioxide (TiO{sub 2}) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti{sup 4+} chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO{sub 2} with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen PIII. - Highlights: • The Ti{sup 4+} chemical state was determined to be present on oxygen-PIII-treated surfaces. • The nanocrystalline TiO{sub 2} with a rutile structure was formed on titanium surfaces. • A nanoporous TiO{sub 2} layer in the rutile phase prepared using oxygen PIII treatment can be used to prolong blood clot formation.

  7. Effects of tiotropium bromide combined with montelukast on blood rheology, pulmonary function and serum cytokine levels in patients with chronic obstructive pulmonary disease

    Directory of Open Access Journals (Sweden)

    Qing-Hua Meng

    2016-11-01

    Full Text Available Objective: To explore the effect of tiotropium bromide combined with montelukast on COPD patients’ blood rheology, pulmonary function and serum cytokine levels. Methods: A total of 82 COPD patients who were treated in our hospital from June 2015 to January 2016 were divided into control group and observation group randomly by half. All patients were given symptomatic and conventional treatment according to the specific circumstances, patients in the control group were treated with 10 mg montelukast with orally once per night on the basis of conventional treatment, and observation group patients was given 18 μg tiotropium bromide inhalation once per night on the basis of control group. All the patients were treated for 4 weeks, the blood rheology indexes, pulmonary function indexes and serum cytokines were measured and compared between the two groups before and after treatment. Results: Before treatment, there was no significant difference in blood rheology index of whole blood viscosity (high shear viscosity, shear viscosity, low shear viscosity, plasma viscosity, hematocrit and fibrinogen (P>0.05; After treatment, the blood rheology indexes of the two groups were significantly decreased compared with that in the same group before treatment (P0.05. After treatment, the indexes of pulmonary function in the two groups were significantly higher than that in the same group before treatment (P0.05; After treatment, the two groups’ serum IL-10, APN levels were significantly increased, IL-18 levels were significantly reduced (P<0.05. Meanwhile, serum IL-10, APN levels in Observation group were significantly increased, IL-18 levels were significantly lower than that in control group (P<0.05. Conclusions: The comibinition of tiotropium bromide with montelukas not only can improve the indexes of blood rheology in patients with COPD, and can significantly control the level of serum cytokines and control symptoms, improve lung function, so it is worth

  8. A prospective functional MRI study for executive function in patients with systemic lupus erythematosus without neuropsychiatric symptoms.

    Science.gov (United States)

    Mak, Anselm; Ren, Tao; Fu, Erin Hui-yun; Cheak, Alicia Ai-cia; Ho, Roger Chun-man

    2012-06-01

    To study the functional brain activation signals before and after sufficient disease control in patients with systemic lupus erythematosus (SLE) without clinical neuropsychiatric symptoms. Blood-oxygen-level-dependent signals during event-related functional magnetic resonance imaging brain were recorded, while 14 new-onset SLE patients and 14 demographically and intelligence quotient matched healthy controls performed the computer-based Wisconsin card sorting test for assessing executive function, which probes strategic planning and goal-directed task performance during feedback evaluation (FE) and response selection (RS), respectively. Composite beta maps were constructed by a general linear model to identify regions of cortical activation. Blood-oxygen-level-dependent functional magnetic resonance imaging signals were compared between (1) new-onset SLE patients and healthy controls and (2) SLE patients before and after sufficient control of their disease activity. During RS, SLE patients demonstrated significantly higher activation than healthy controls in both caudate bodies and Brodmann area (BA) 9 to enhance event anticipation, attention, and working memory, respectively, to compensate for the reduced activation during FE in BA6, 13, 24, and 32, which serve complex motor planning and decision-making, sensory integration, error detection, and conflict processing, respectively. Despite significant reduction of SLE activity, BA32 was activated during RS to compensate for reduced activation during FE in BA6, 9, 37, and 23/32, which serve motor planning, response inhibition and attention, color processing and word recognition, error detection, and conflict evaluation, respectively. Even without clinically overt neuropsychiatric symptoms, SLE patients recruited additional pathways to execute goal-directed tasks to compensate for their reduced strategic planning skill despite clinically sufficient disease control. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. The features of 24-hour ambulatory blood pressure in patients with diabetes mellitus depending on endothelial dysfunction

    Directory of Open Access Journals (Sweden)

    N.O. Pertseva

    2018-03-01

    Full Text Available Background. Arterial hypertension in patients with diabetes mellitus (DM plays a main role in the earlier formation of diabetic kidney disease (DKD. Endothelial dysfunction is considered to be a process based on the development of diabetic complications. It is important to study the markers, which gives the opportunity to identify DKD in early stage. Objective: to evaluate 24-h ambulatory blood pressure data in patients with DM and its correlation with estimated glomerular filtration rate and endothelial dysfunction. Materials and methods. The endothelial function was determined by the levels of transforming growth factor-beta 1 (TGF-b1 and vascular cell adhesion molecule 1 (VCAM-1. There were 124 patients with DM (66 with type 1 and 58 with type 2 under observation. Results. Levels of endothelial function (TGF-b1 and VCAM-1 indexes in patients with type 1 and type 2 DM depended on glomerular filtration rate. Between the indexes of endothelial function (TGF-b1, VCAM-1 and the 24-hour ambulatory blood pressure, there is strong and average correlation, therefore, parameters of 24-hour ambulatory blood pressure and presence of endothelial dysfunction can be considered as early signs of DKD progression in patients with DM. Conclusions. 24-hour ambulatory blood pressure in patients with DM on the early stages of diabetic nephropathy is characterized by significant circadian rhythm disorders. The insufficient night decline of blood pressure in patients with type 1 and type 2 DM characterizes the presence of diabetic nephropathy progression according to the indexes of 24-h ambulatory blood pressure.

  10. Database of normal human cerebral blood flow, cerebral blood volume, cerebral oxygen extraction fraction and cerebral metabolic rate of oxygen measured by positron emission tomography with {sup 15}O-labelled carbon dioxide or water, carbon monoxide and oxygen: a multicentre study in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hiroshi [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Department of Nuclear Medicine and Radiology, Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, 4-1 Seiryo-Machi, 980-8575, Aoba-Ku, Sendai (Japan); Kanno, Iwao [Department of Radiology and Nuclear Medicine, Akita Research Institute of Brain and Blood Vessels, Akita (Japan); Kato, Chietsugu [Department of Nuclear Medicine, Hokkaido University School of Medicine, Sapporo (Japan); Sasaki, Toshiaki [Cyclotoron Research Center, Iwate Medical University, Morioka (Japan); Ishii, Kenji [Positron Medical Center, Tokyo Metropolitan Institute of Gerontology, Tokyo (Japan); Ouchi, Yasuomi [Positron Medical Center, Hamamatsu Medical Center, Hamakita (Japan); Iida, Akihiko [Nagoya City Rehabilitation Center, Nagoya (Japan); Okazawa, Hidehiko [PET Unit, Research Institute, Shiga Medical Center, Moriyama (Japan); Hayashida, Kohei [Department of Radiology, National Cardiovascular Center, Suita, Osaka (Japan); Tsuyuguchi, Naohiro [Department of Neurosurgery, Osaka City University Medical School, Osaka (Japan); Ishii, Kazunari [Division of Imaging Research, Hyogo Institute for Aging Brain and Cognitive Disorders, Himeji, Hyogo (Japan); Kuwabara, Yasuo [Department of Radiology, Faculty of Medicine, Kyushu University, Fukuoka (Japan); Senda, Michio [Department of Image-based Medicine, Institute of Biomedical Research and Innovation, Kobe (Japan)

    2004-05-01

    Measurement of cerebral blood flow (CBF), cerebral blood volume (CBV), cerebral oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO{sub 2}) by positron emission tomography (PET) with oxygen-15 labelled carbon dioxide (C{sup 15}O{sub 2}) or {sup 15}O-labelled water (H{sub 2}{sup 15}O), {sup 15}O-labelled carbon monoxide (C{sup 15}O) and {sup 15}O-labelled oxygen ({sup 15}O{sub 2}) is useful for diagnosis and treatment planning in cases of cerebrovascular disease. The measured values theoretically depend on various factors, which may differ between PET centres. This study explored the applicability of a database of {sup 15}O-PET by examining between-centre and within-centre variation in values. Eleven PET centres participated in this multicentre study; seven used the steady-state inhalation method, one used build-up inhalation and three used bolus administration of C{sup 15}O{sub 2} (or H{sub 2}{sup 15}O) and {sup 15}O{sub 2}. All used C{sup 15}O for measurement of CBV. Subjects comprised 70 healthy volunteers (43 men and 27 women; mean age 51.8{+-}15.1 years). Overall mean{+-}SD values for cerebral cortical regions were: CBF=44.4{+-}6.5 ml 100 ml{sup -1} min{sup -1}; CBV=3.8{+-}0.7 ml 100 ml{sup -1}; OEF=0.44{+-}0.06; CMRO{sub 2}=3.3{+-}0.5 ml 100 ml{sup -1} min{sup -1}. Significant between-centre variation was observed in CBV, OEF and CMRO{sub 2} by one-way analysis of variance. However, the overall inter-individual variation in CBF, CBV, OEF and CMRO{sub 2} was acceptably small. Building a database of normal cerebral haemodynamics obtained by the{sup 15}O-PET methods may be practicable. (orig.)

  11. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    Energy Technology Data Exchange (ETDEWEB)

    Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

  12. Oxygen effect and intracellular oxygen content (adaptation hypothesis)

    International Nuclear Information System (INIS)

    Yarmonenko, S.P.; Ehpshtejn, I.M.

    1977-01-01

    Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

  13. [Chronic low-grade inflammation, lipid risk factors and mortality in functionally dependent elderly].

    Science.gov (United States)

    Vasović, Olga; Trifunović, Danijela; Despotovié, Nebojsa; Milosević, Dragoslav P

    2010-07-01

    It has been proved that a highly sensitive C-reactive protein (hsCRP) can be used as an established marker of chronic inflammation for cardiovascular risk assessment. Since mean values of both low-density cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) decrease during aging, the knowledge that increased hsCRP concentration predicts mortality (Mt) would influence therapy and treatment outcome. The aim of this study was to examine importance of chronic low grade inflammation and its association with lipid risk factors for all-cause Mt in functionally dependent elderly. The participants of this longitudinal prospective study were 257 functionally dependent elderly aged 65-99 years. Baseline measurements: anthropometric measurements, blood pressure, fasting plasma total cholesterol (TC), triglyceride (TG), HDL-C, LDL-C, non-HDL-C, hemoglobin Alc (HbA1c) were recorded and different lipid ratios were calculated. Inflammation was assessed by the levels of white blood cells, fibrinogen and hsCRP. The participants with hsCRP grater than 10 mg/L were excluded from the study. The residual participants (77.4% women) were divided into three groups according to their hsCRP levels: a low (agressive lipid lowering treatment.

  14. Galanin regulates blood glucose level in the zebrafish: a morphological and functional study.

    Science.gov (United States)

    Podlasz, P; Jakimiuk, A; Chmielewska-Krzesinska, M; Kasica, N; Nowik, N; Kaleczyc, J

    2016-01-01

    The present study has demonstrated the galaninergic innervation of the endocrine pancreas including sources of the galaninergic nerve fibers, and the influence of galanin receptor agonists on blood glucose level in the zebrafish. For the first time, a very abundant galaninergic innervation of the endocrine pancreas during development is shown, from the second day post-fertilization to adulthood. The fibers originated from ganglia consisting of galanin-IR, non-adrenergic (non-sensory) neurons located rostrally to the pancreatic tissue. The ganglia were found on the dorsal side of the initial part of the anterior intestinal segment, close to the intestinal branch of the vagus nerve. The galanin-IR neurons did not show immunoreactivity for applied antibodies against tyrosine hydroxylase, choline acetyltransferase, and vesicular acetylcholine transporter. Intraperitoneal injections of galanin analog NAX 5055 resulted in a statistically significant increase in the blood glucose level. Injections of another galanin receptor agonist, galnon, also caused a rise in blood glucose level; however, it was not statistically significant. The present findings suggest that, like in mammals, in the zebrafish galanin is involved in the regulation of blood glucose level. However, further studies are needed to elucidate the exact mechanism of the galanin action.

  15. Red blood cell labeling with technetium-99m. Effect of radiopaque contrast agents

    International Nuclear Information System (INIS)

    Finkel, J.; Chervu, L.R.; Bernstein, R.G.; Srivastava, S.C.

    1988-01-01

    Radiographic contrast agents have been reported in the literature to interfere significantly with red blood cell (RBC) labeling in vivo by Tc-99m. Moreover, in the presence of contrast agents, red cells have been known to undergo significant morphologic changes. These observations led to the current RBC labeling study in patients (N = 25) undergoing procedures with the administration of contrast media. Before and after contrast administration, blood samples were drawn from each patient into vacutainer tubes containing heparin and RBC labeling was performed using 1-ml aliquots of these samples following the Brookhaven National Laboratory protocol. The differences in average percentage labeling yield with and without contrast media were not significant. In vivo labeling in hypertensive rats with administration of contrast media up to 600 mg likewise consistently gave high labeling yields at all concentrations. Purported alterations in cell labeling attributed to contrast agents are not reflected in these studies, and other pathophysiologic factors need to be identified to substantiate the previous reports. In vitro study offers a potentially useful and simple method to delineate effects of various agents on cell labeling

  16. SUN family proteins Sun4p, Uth1p and Sim1p are secreted from Saccharomyces cerevisiae and produced dependently on oxygen level.

    Directory of Open Access Journals (Sweden)

    Evgeny Kuznetsov

    Full Text Available The SUN family is comprised of proteins that are conserved among various yeasts and fungi, but that are absent in mammals and plants. Although the function(s of these proteins are mostly unknown, they have been linked to various, often unrelated cellular processes such as those connected to mitochondrial and cell wall functions. Here we show that three of the four Saccharomyces cerevisiae SUN family proteins, Uth1p, Sim1p and Sun4p, are efficiently secreted out of the cells in different growth phases and their production is affected by the level of oxygen. The Uth1p, Sim1p, Sun4p and Nca3p are mostly synthesized during the growth phase of both yeast liquid cultures and colonies. Culture transition to slow-growing or stationary phases is linked with a decreased cellular concentration of Sim1p and Sun4p and with their efficient release from the cells. In contrast, Uth1p is released mainly from growing cells. The synthesis of Uth1p and Sim1p, but not of Sun4p, is repressed by anoxia. All four proteins confer cell sensitivity to zymolyase. In addition, Uth1p affects cell sensitivity to compounds influencing cell wall composition and integrity (such as Calcofluor white and Congo red differently when growing on fermentative versus respiratory carbon sources. In contrast, Uth1p is essential for cell resistance to boric acids irrespective of carbon source. In summary, our novel findings support the hypothesis that SUN family proteins are involved in the remodeling of the yeast cell wall during the various phases of yeast culture development and under various environmental conditions. The finding that Uth1p is involved in cell sensitivity to boric acid, i.e. to a compound that is commonly used as an important antifungal in mycoses, opens up new possibilities of investigating the mechanisms of boric acid's action.

  17. RegA Plays a Key Role in Oxygen-Dependent Establishment of Persistence and in Isocitrate Lyase Activity, a Critical Determinant of In vivo Brucella suis Pathogenicity

    Directory of Open Access Journals (Sweden)

    Elias Abdou

    2017-05-01

    Full Text Available For aerobic human pathogens, adaptation to hypoxia is a critical factor for the establishment of persistent infections, as oxygen availability is low inside the host. The two-component system RegB/A of Brucella suis plays a central role in the control of respiratory systems adapted to oxygen deficiency, and in persistence in vivo. Using an original “in vitro model of persistence” consisting in gradual oxygen depletion, we compared transcriptomes and proteomes of wild-type and ΔregA strains to identify the RegA-regulon potentially involved in the set-up of persistence. Consecutive to oxygen consumption resulting in growth arrest, 12% of the genes in B. suis were potentially controlled directly or indirectly by RegA, among which numerous transcriptional regulators were up-regulated. In contrast, genes or proteins involved in envelope biogenesis and in cellular division were repressed, suggesting a possible role for RegA in the set-up of a non-proliferative persistence state. Importantly, the greatest number of the RegA-repressed genes and proteins, including aceA encoding the functional IsoCitrate Lyase (ICL, were involved in energy production. A potential consequence of this RegA impact may be the slowing-down of the central metabolism as B. suis progressively enters into persistence. Moreover, ICL is an essential determinant of pathogenesis and long-term interactions with the host, as demonstrated by the strict dependence of B. suis on ICL activity for multiplication and persistence during in vivo infection. RegA regulates gene or protein expression of all functional groups, which is why RegA is a key regulator of B. suis in adaptation to oxygen depletion. This function may contribute to the constraint of bacterial growth, typical of chronic infection. Oxygen-dependent activation of two-component systems that control persistence regulons, shared by several aerobic human pathogens, has not been studied in Brucella sp. before. This work

  18. The effects of altitude/hypoxic training on oxygen delivery capacity of the blood and aerobic exercise capacity in elite athletes – a meta-analysis

    Science.gov (United States)

    Park, Hun-young; Hwang, Hyejung; Park, Jonghoon; Lee, Seongno; Lim, Kiwon

    2016-01-01

    [Purpose] This study was designed as a meta-analysis of randomized controlled trials comparing effectiveness of altitude/hypoxic training (experimental) versus sea-level training (control) on oxygen delivery capacity of the blood and aerobic exercise capacity of elite athletes in Korea. [Methods] Databases (Research Information Service System, Korean studies Information Service System, National Assembly Library) were for randomized controlled trials comparing altitude/hypoxic training versus sea-level training in elite athletes. Studies published in Korea up to December 2015 were eligible for inclusion. Oxygen delivery capacity of the blood was quantified by red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), erythropoietin (EPO); and aerobic exercise capacity was quantified by maximal oxygen consumption (VO2max). RBC, Hb, Hct, VO2max represented heterogeneity and compared post-intervention between altitude/hypoxic training and sea-level training in elite athletes by a random effect model meta-analysis. EPO represented homogeneity and meta-analysis performed by a fixed effect model. Eight independent studies with 156 elite athletes (experimental: n = 82, control: n = 74) were included in the metaanalysis. [Results] RBC (4.499×105 cell/ul, 95 % CI: 2.469 to 6.529), Hb (5.447 g/dl, 95 % CI: 3.028 to 7.866), Hct (3.639 %, 95 % CI: 1.687 to 5.591), EPO (0.711 mU/mL, 95% CI: 0.282 to 1.140), VO2max (1.637 ml/kg/min, 95% CI: 0.599 to 1.400) showed significantly greater increase following altitude/hypoxic training, as compared with sea-level training. [Conclusion] For elite athletes in Korea, altitude/ hypoxic training appears more effective than sea-level training for improvement of oxygen delivery capacity of the blood and aerobic exercise capacity. PMID:27298808

  19. Diltiazem enhances tumor blood flow: MRI study in a murine tumor

    International Nuclear Information System (INIS)

    Muruganandham, M.; Kasiviswanathan, A.; Jagannathan, N.R.; Raghunathan, P.; Jain, P.C.; Jain, V.

    1999-01-01

    Purpose: Diltiazem, a calcium-channel blocker, is known to differentially influence the radiation responses of normal and murine tumor tissues. To elucidate the underlying mechanisms, the effects of diltiazem on the radiation response of Ehrlich ascites tumor (EAT) in mice have been investigated, and the hemodynamic changes induced by diltiazem in tumor and normal muscle have been studied using magnetic resonance imaging (MRI) techniques. Methods and Materials: Ehrlich ascites tumors were grown subcutaneously in Swiss albino strain A mice. Dynamic gadodiamide and blood oxygen level dependent (BOLD) contrast enhanced 1 H MR imaging studies of EAT and normal muscle were performed after administration of diltiazem in mice using a 4.7 Tesla MR scanner. Tumor radiotherapy experiments (total dose = 10 Gy, 0.4-0.5 Gy/min, single fraction) were carried out with 30 min preadministration of diltiazem (27.5 or 55 mg/kg i.p.) to EAT-bearing mice using a teletherapy machine. Results: The diltiazem+ radiation treated group showed significant tumor regression (in congruent with 65% of the animals) and enhanced animal survival. MR-gadodiamide contrast kinetics revealed a higher magnitude of signal enhancement in diltiazem treated groups as compared to the controls. The observed changes in the magnitude of kinetic parameters were the same for both tumor and normal muscle. BOLD-MR images at 30 min after diltiazem administration showed a 25% and 8% (average) intensity enhancement from their basal values in tumor and normal muscle regions, respectively. The control group showed no significant changes. Conclusion: The present studies demonstrate the radiosensitization potential of diltiazem in the mice EAT model. The enhanced radiation response observed with diltiazem correlates with the diltiazem-induced increase in tumor blood flow (TBF) and tumor oxygenation. The present results also demonstrate the applications of BOLD-MR measurements in investigating the alterations in tumor

  20. Influence of uranium dioxide nonstoichiometric oxygen on the work function of Mo(110) single crystal

    International Nuclear Information System (INIS)

    Bekmukhabetov, E.S.; Dzhajmurzin, A.A.; Imanbekov, Zh.Zh.

    1985-01-01

    The influence of the uranium dioxide nonstoichiometric oxygen on the work function of a Mo(110) single crystal has been studied. When the surface diffusion of oxygen on the tested surface takes place, the work function is shown to decrease and, subsequently, to increase until it becomes stable. The dependence of the work function on the temperature of the specimen in the range of 1600-1900 K with a minimum at 1730 K has been found. The minimum is attributed to the dipole layer formation

  1. Thermal- and pH-Dependent Size Variable Radical Nanoparticles and Its Water Proton Relaxivity for Metal-Free MRI Functional Contrast Agents.

    Science.gov (United States)

    Morishita, Kosuke; Murayama, Shuhei; Araki, Takeru; Aoki, Ichio; Karasawa, Satoru

    2016-09-16

    For development of the metal-free MRI contrast agents, we prepared the supra-molecular organic radical, TEMPO-UBD, carrying TEMPO radical, as well as the urea, alkyl group, and phenyl ring, which demonstrate self-assembly behaviors using noncovalent bonds in an aqueous solution. In addition, TEMPO-UBD has the tertiary amine and the oligoethylene glycol chains (OEGs) for the function of pH and thermal responsiveness. By dynamic light scattering and transmission electron microscopy imaging, the resulting self-assembly was seen to form the spherical nanoparticles 10-150 nm in size. On heating, interestingly, the nanoparticles showed a lower critical solution temperature (LCST) behavior having two-step variation. This double-LCST behavior is the first such example among the supra-molecules. To evaluate of the ability as MRI contrast agents, the values of proton ((1)H) longitudinal relaxivity (r1) were determined using MRI apparatus. In conditions below and above CAC at pH 7.0, the distinguishable r1 values were estimated to be 0.17 and 0.21 mM(-1) s(1), indicating the suppression of fast tumbling motion of TEMPO moiety in a nanoparticle. Furthermore, r1 values became larger in the order of pH 7.0 > 9.0 > 5.0. Those thermal and pH dependencies indicated the possibility of metal-fee MRI functional contrast agents in the future.

  2. Oxygen Concentration Inside a Functioning Photosynthetic Cell

    OpenAIRE

    Kihara, Shigeharu; Hartzler, Daniel A.; Savikhin, Sergei

    2014-01-01

    The excess oxygen concentration in the photosynthetic membranes of functioning oxygenic photosynthetic cells was estimated using classical diffusion theory combined with experimental data on oxygen production rates of cyanobacterial cells. The excess oxygen concentration within the plesiomorphic cyanobacterium Gloeobactor violaceus is only 0.025 μM, or four orders of magnitude lower than the oxygen concentration in air-saturated water. Such a low concentration suggests that the first oxygenic...

  3. Haptoglobin blood test

    Science.gov (United States)

    The haptoglobin blood test measures the level of haptoglobin in your blood. Haptoglobin is a protein produced by the liver. It attaches to a certain type of hemoglobin in the blood. Hemoglobin is a blood cell that carries oxygen.

  4. Improved sample capsule for determination of oxygen in hemolyzed blood

    Science.gov (United States)

    Malik, W. M.

    1967-01-01

    Sample capsule for determination of oxygen in hemolyzed blood consists of a measured section of polytetrafluoroethylene tubing equipped at each end with a connector and a stopcock valve. This method eliminates errors from air entrainment or from the use of mercury or syringe lubricant.

  5. Fuel cell serves as oxygen level detector

    Science.gov (United States)

    1965-01-01

    Monitoring the oxygen level in the air is accomplished by a fuel cell detector whose voltage output is proportional to the partial pressure of oxygen in the sampled gas. The relationship between output voltage and partial pressure of oxygen can be calibrated.

  6. Time-dependent change of blood flow in the prostate treated with high-intensity focused ultrasound.

    Science.gov (United States)

    Shoji, Sunao; Tonooka, Akiko; Hashimoto, Akio; Nakamoto, Masahiko; Tomonaga, Tetsuro; Nakano, Mayura; Sato, Haruhiro; Terachi, Toshiro; Koike, Junki; Uchida, Toyoaki

    2014-09-01

    Avascular areas on contrast-enhanced magnetic resonance imaging have been considered to be areas of localized prostate cancer successfully treated by high-intensity focused ultrasound. However, the optimal timing of magnetic resonance imaging has not been discussed. The thermal effect of high-intensity focused ultrasound is degraded by regional prostatic blood flow. Conversely, the mechanical effect of high-intensity focused ultrasound (cavitation) is not affected by blood flow, and can induce vessel damage. In this series, the longitudinal change of blood flow on contrast-enhanced magnetic resonance imaging was observed from postoperative day 1 to postoperative day 14 in 10 patients treated with high-intensity focused ultrasound. The median rates of increase in the non-enhanced volume of the whole gland, transition zone and peripheral zone from postoperative day 1 to postoperative day 14 were 36%, 39%, and 34%, respectively. In another pathological analysis of the prostate tissue of 17 patients immediately after high-intensity focused ultrasound without neoadjuvant hormonal therapy, we observed diffuse coagulative degeneration and partial non-coagulative prostate tissue around arteries with vascular endothelial cell detachment. These observations on contrast-enhanced magnetic resonance imaging support a time-dependent change of the blood flow in the prostate treated with high-intensity focused ultrasound. Additionally, our pathological findings support the longitudinal changes of these magnetic resonance imaging findings. Further large-scale studies will investigate the most appropriate timing of contrast-enhanced magnetic resonance imaging for evaluation of the effectiveness of high-intensity focused ultrasound for localized prostate cancer. © 2014 The Japanese Urological Association.

  7. [Correlation between the inspired fraction of oxygen, maternal partial oxygen pressure, and fetal partial oxygen pressure during cesarean section of normal pregnancies].

    Science.gov (United States)

    Castro, Carlos Henrique Viana de; Cruvinel, Marcos Guilherme Cunha; Carneiro, Fabiano Soares; Silva, Yerkes Pereira; Cabral, Antônio Carlos Vieira; Bessa, Roberto Cardoso

    2009-01-01

    Despite changes in pulmonary function, maternal oxygenation is maintained during obstetric regional blocks. But in those situations, the administration of supplementary oxygen to parturients is a common practice. Good fetal oxygenation is the main justification; however, this has not been proven. The objective of this randomized, prospective study was to test the hypothesis of whether maternal hyperoxia is correlated with an increase in fetal gasometric parameters in elective cesarean sections. Arterial blood gases of 20 parturients undergoing spinal block with different inspired fractions of oxygen were evaluated and correlated with fetal arterial blood gases. An increase in maternal inspired fraction of oxygen did not show any correlation with an increase of fetal partial oxygen pressure. Induction of maternal hyperoxia by the administration of supplementary oxygen did not increase fetal partial oxygen pressure. Fetal gasometric parameters did not change even when maternal parameters changed, induced by hyperoxia, during cesarean section under spinal block.

  8. Correlation of salivary glucose level with blood glucose level in diabetes mellitus.

    Science.gov (United States)

    Gupta, Shreya; Nayak, Meghanand T; Sunitha, J D; Dawar, Geetanshu; Sinha, Nidhi; Rallan, Neelakshi Singh

    2017-01-01

    Saliva is a unique fluid, which is important for normal functioning of the oral cavity. Diabetes mellitus (DM) is a disease of absolute or relative insulin deficiency characterized by insufficient secretion of insulin by pancreatic beta-cells. The diagnosis of diabetes through blood is difficult in children, older adults, debilitated and chronically ill patients, so diagnosis by analysis of saliva can be potentially valuable as collection of saliva is noninvasive, easier and technically insensitive, unlike blood. The aim of the study was to correlate blood glucose level (BGL) and salivary glucose level (SGL) in DM patients. A cross-sectional study was conducted in 120 patients, who were categorized as 40 controlled diabetics, 40 uncontrolled diabetics and 40 healthy, age- and sex-matched individuals constituted the controls. The blood and unstimulated saliva samples were collected from the patients at the different intervals for fasting, random and postprandial levels. These samples were then subjected for analysis of glucose in blood and saliva using glucose oxidase/peroxidase reagent in HITACHI 902 (R) Automatic analyzer, and the results were recorded. The mean SGLs were higher in uncontrolled and controlled diabetic groups than in nondiabetic group. A highly statistically significant correlation was found between fasting saliva glucose and fasting blood glucose in all the groups. With increase in BGL, increase in SGL was observed in patients with diabetes suggesting that SGL can be used for monitoring glycemic level in DM.

  9. Phase contrast MRI assessment of pedal blood flow

    International Nuclear Information System (INIS)

    Debatin, J.F.; Dalman, R.; Herfkens, R.J.; Harris, E.J.; Pelc, N.J.

    1995-01-01

    This study attempts to evaluate the reliability of cine phase contrast (PC) flow measurements in the assessment of normal pedal blood flow and quantitation of revascularisation-induced flow changes in patients with end-stage peripheral vascular occlusive disease (PVOD). Oblique axial cine-PC acquisitions were obtained on a 1.5 T MRI system at the level of the talotibial joints in 8 normal subjects on four separate occasions. Subsequently 8 patients with end-stage PVOD were examined before and after surgical revascularisation (bilateral, n = 2; unilateral, n = 6). Measured flow in the trifurcation vessels was highly variable among normal subjects. Total pedal flow ranged from 32 to 183 ml/min (mean 91 ml/min) and was significantly different between the subjects evaluated (P < 0.0001). Measurements in the same subject over time were considerably less variable (P < 0.005). Normal arterial flow patterns were consistently triphasic; those in patients with PVOD were either mono- or biphasic. Pedal flow measured by cine-PC in patients was reduced compared with normal subjects (mean 38.3 ml/min). Flow was slower in symptomatic limbs (26.7 ml/min) compared with asymptomatic ones (48.9 ml/min). Flow increases in revascularised limbs (mean 315%) were significantly different from those observed in non-affected limbs (P < 0.005). The ability to quantitate pedal blood flow and subsequent revascularisation-induced flow increases appears promising for the identification of optimal treatment options and monitoring of treatment results. (orig.)

  10. Cord blood testing

    Science.gov (United States)

    ... Blood culture (if an infection is suspected) Blood gases (including oxygen, carbon dioxide, and pH levels) Blood ... 2018, A.D.A.M., Inc. Duplication for commercial use must be authorized in writing by ADAM ...

  11. Cerebral blood flow and cerebral oxygen metabolism in thalamic hemorrhage

    International Nuclear Information System (INIS)

    Yasui, Nobuyuki; Asakura, Ken

    1987-01-01

    Cerebral blood flow (CBF), cerebral oxygen consumption (CMRO 2 ), oxygen extraction fraction (OEF) and cerebral blood volume (CBV) were studied in 20 cases of thalamic hemorrhage using positron CT and 15 O labeled gas steady-state inhalation method. CBF reduction was limited around the thalamus in the small sized hematoma. CBF were significantly diminished in the mean cortical, parietal, temporal, basal ganglia and thalamic area ipsilateral and cerebellar cortex contralateral to the medium sized hematoma. There was bilateral and diffuse CBF reduction in the large sized hematoma which was caused by increased intracranial pressure. CMRO 2 value were similary changed as CBF. OEF change showed within normal limit. Diffuse CBV reduction was observed in the large sized hematoma. This reduction was the result of decreased vascular bed caused by mass effect of the hematoma and hydrocephalus. Effect of surgical treatment such as ventricular drainage and hematoma evacuation were also discussed in correlation to CBF in some case using positron and single photon ECT. (author)

  12. Modulation of oxygen-dependent and oxygen-independent metabolism of neutrophilic granulocytes by quantum points.

    Science.gov (United States)

    Pleskova, S N; Mikheeva, E R

    2011-08-01

    Inhibition of neutrophilic granulocyte metabolism under the effect of semiconductor quantum points was demonstrated. The status of the oxidative system was evaluated by the NBT test, nonoxidative status by the lysosomal cationic test. It was found that quantum points in a dose of 0.1 mg/ml irrespective of their core and composition of coating significantly inhibited oxygen-dependent and oxygen-independent metabolism of neutrophilic granulocytes.

  13. Betel Leaf Extract (Piper betle L. Antihyperuricemia Effect Decreases Oxidative Stress by Reducing the Level of MDA and Increase Blood SOD Levels of Hyperuricemia Wistar Rats (Rattus norvegicus

    Directory of Open Access Journals (Sweden)

    I Made Sumarya

    2016-06-01

    Full Text Available Background: Betel leaf extracts (Piper betle L. antioxidant activity and enzyme inhibitors of XO. Hyperuricemia cause oxidative stress by increasing the formation of reactive oxygen species (ROS cause lipid peroxidation and oxygenation of low-density lipoprotein cholesterol (LDLc. Objective: The aim of this research was to determine the betel leaf extract as an anti hyperuricemia that can lower the blood uric acid levels and oxidative stress by lowering the levels of MDA and increase the SOD of hyperuricemia of the rat’s blood. Method: Experimental research was conducted with the design of The Randomized Post Test Only Control Group Design, on normal Wistar rats (Rattus norvegicus, administered with oxonic potassium (hyperuricemia and the hyperuricemia rats either given betel leaf extract and allopurinol. After the experiment of uric acid levels, MDA and SOD in rat blood determined. Results: The results showed that the betel leaf extract significantly (p <0.05 lower uric acid levels, MDA and increase levels of SOD in rat blood. There is a positive correlation between the levels of uric acid with MDA levels and a negative correlation, although not significantly with SOD (p >0.05. Conclusion: It can be concluded that the betel leaf extract as an anti-hyperuricemia can lower the uric acid levels and decreases oxidative stress by lowering the levels of MDA and increasing the SOD.

  14. Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

    International Nuclear Information System (INIS)

    Mitamura, Yoshinori; Okamoto, Eiji

    2015-01-01

    This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator

  15. Numerical analysis of the effects of a high gradient magnetic field on flowing erythrocytes in a membrane oxygenator

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Yoshinori, E-mail: ymitamura@par.odn.ne.jp; Okamoto, Eiji, E-mail: okamoto@tspirit.tokai-u.jp

    2015-04-15

    This study was carried out to clarify the effect of a high gradient magnetic field on pressure characteristics of blood in a hollow fiber membrane oxygenator in a solenoid coil by means of numerical analysis. Deoxygenated erythrocytes are paramagnetic, and oxygenated erythrocytes are diamagnetic. Blood changes its magnetic susceptibility depending on whether it is carrying oxygen or not. Motion of blood was analyzed by solving the continuous equation and the Navier–Stokes equation. It was confirmed that oxygenation of deoxygenated blood in the downstream side of the applied magnetic field was effective for pressure rise in a non-uniform magnetic field. The pressure rise was enhanced greatly by an increase in magnetic field intensity. The results suggest that a membrane oxygenator works as an actuator and there is a possibility of self-circulation of blood through an oxygenator in a non-uniform magnetic field. - Highlights: • Effects of a gradient magnetic field on erythrocytes in an oxygenator were analyzed. • Blood changes magnetic susceptibility depending on if it is carrying oxygen or not. • Oxygenation of deoxygenated blood is effective for pressure rise in a magnetic field. • A membrane oxygenator works as an actuator. • There is a possibility of self-circulation of blood through an oxygenator.

  16. A brief clinical case of monitoring of oxygenator performance and patient-machine interdependency during prolonged veno-venous extracorporeal membrane oxygenation.

    Science.gov (United States)

    Belliato, Mirko; Degani, Antonella; Buffa, Antonino; Sciutti, Fabio; Pagani, Michele; Pellegrini, Carlo; Iotti, Giorgio Antonio

    2017-10-01

    Monitoring veno-venous extracorporeal membrane oxygenation (vvECMO) during 76 days of continuous support in a 42-years old patient with end-stage pulmonary disease, listed for double-lung transplantation. Applying a new monitor (Landing ® , Eurosets, Medolla, Italy) and describing how measured and calculated parameters can be used to understand the variable interdependency between artificial membrane lung (ML) and patient native lung (NL). During vvECMO, in order to understand how the respiratory function is shared between ML and NL, ideally we should obtain data about oxygen transfer and CO 2 removal, both by ML and NL. Measurements for NL can be made on the mechanical ventilator. Measurements for ML are typically made from gas analysis on blood samples drawn from the ECMO system before and after the oxygenator, and therefore are non-continuous. Differently, the Landing monitor provides a continuous measurement of the oxygen transfer from the ML, combined with hemoglobin level, saturation of drained blood and saturation of reinfused blood. Moreover, the Landing monitor provides hemodynamics data about circulation through the ECMO system, with blood flow, pre-oxygenator pressure and post-oxygenator pressure. Of note, measurements include the drain negative pressure, whose monitoring may be particularly useful to prevent hemolysis. Real-time monitoring of vvECMO provides data helpful to understand the complex picture of a patient with severely damaged lungs on one side and an artificial lung on the other side. Data from vvECMO monitoring may help to adapt the settings of both mechanical ventilator and vvECMO. Data about oxygen transfer by the oxygenator are important to evaluate the performance of the device and may help to avoid unnecessary replacements, thus reducing risks and costs.

  17. Non-invasive evaluation of blood oxygen saturation and hematocrit from T1 and T2 relaxation times: In-vitro validation in fetal blood.

    Science.gov (United States)

    Portnoy, Sharon; Seed, Mike; Sled, John G; Macgowan, Christopher K

    2017-12-01

    We propose an analytical method for calculating blood hematocrit (Hct) and oxygen saturation (sO 2 ) from measurements of its T 1 and T 2 relaxation times. Through algebraic substitution, established two-compartment relationships describing R1=T1-1 and R2=T2-1 as a function of hematocrit and oxygen saturation were rearranged to solve for Hct and sO 2 in terms of R 1 and R 2 . Resulting solutions for Hct and sO 2 are the roots of cubic polynomials. Feasibility of the method was established by comparison of Hct and sO 2 estimates obtained from relaxometry measurements (at 1.5 Tesla) in cord blood specimens to ground-truth values obtained by blood gas analysis. Monte Carlo simulations were also conducted to assess the effect of T 1 , T 2 measurement uncertainty on precision of Hct and sO 2 estimates. Good agreement was observed between estimated and ground-truth blood properties (bias = 0.01; 95% limits of agreement = ±0.13 for Hct and sO 2 ). Considering the combined effects of biological variability and random measurement noise, we estimate a typical uncertainty of ±0.1 for Hct, sO 2 estimates. Results demonstrate accurate quantification of Hct and sO 2 from T 1 and T 2 . This method is applicable to noninvasive fetal vessel oximetry-an application where existing oximetry devices are unusable or require risky blood-sampling procedures. Magn Reson Med 78:2352-2359, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  18. Technical Note: Measuring contrast- and noise-dependent spatial resolution of an iterative reconstruction method in CT using ensemble averaging

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Lifeng, E-mail: yu.lifeng@mayo.edu; Vrieze, Thomas J.; Leng, Shuai; Fletcher, Joel G.; McCollough, Cynthia H. [Department of Radiology, Mayo Clinic, Rochester, Minnesota 55905 (United States)

    2015-05-15

    Purpose: The spatial resolution of iterative reconstruction (IR) in computed tomography (CT) is contrast- and noise-dependent because of the nonlinear regularization. Due to the severe noise contamination, it is challenging to perform precise spatial-resolution measurements at very low-contrast levels. The purpose of this study was to measure the spatial resolution of a commercially available IR method using ensemble-averaged images acquired from repeated scans. Methods: A low-contrast phantom containing three rods (7, 14, and 21 HU below background) was scanned on a 128-slice CT scanner at three dose levels (CTDI{sub vol} = 16, 8, and 4 mGy). Images were reconstructed using two filtered-backprojection (FBP) kernels (B40 and B20) and a commercial IR method (sinogram affirmed iterative reconstruction, SAFIRE, Siemens Healthcare) with two strength settings (I40-3 and I40-5). The same scan was repeated 100 times at each dose level. The modulation transfer function (MTF) was calculated based on the edge profile measured on the ensemble-averaged images. Results: The spatial resolution of the two FBP kernels, B40 and B20, remained relatively constant across contrast and dose levels. However, the spatial resolution of the two IR kernels degraded relative to FBP as contrast or dose level decreased. For a given dose level at 16 mGy, the MTF{sub 50%} value normalized to the B40 kernel decreased from 98.4% at 21 HU to 88.5% at 7 HU for I40-3 and from 97.6% to 82.1% for I40-5. At 21 HU, the relative MTF{sub 50%} value decreased from 98.4% at 16 mGy to 90.7% at 4 mGy for I40-3 and from 97.6% to 85.6% for I40-5. Conclusions: A simple technique using ensemble averaging from repeated CT scans can be used to measure the spatial resolution of IR techniques in CT at very low contrast levels. The evaluated IR method degraded the spatial resolution at low contrast and high noise levels.

  19. Quantifying the correlation between spatially defined oxygen gradients and cell fate in an engineered three-dimensional culture model

    OpenAIRE

    Ardakani, Amir G.; Cheema, Umber; Brown, Robert A.; Shipley, Rebecca J.

    2014-01-01

    A challenge in three-dimensional tissue culture remains the lack of quantitative information linking nutrient delivery and cellular distribution. Both in vivo and in vitro, oxygen is delivered by diffusion from its source (blood vessel or the construct margins). The oxygen level at a defined distance from its source depends critically on the balance of diffusion and cellular metabolism. Cells may respond to this oxygen environment through proliferation, death and chemotaxis, resulting in spat...

  20. Prevalence and determinants of declining versus stable hemoglobin levels in whole blood donors

    NARCIS (Netherlands)

    Nasserinejad, Kazem; van Rosmalen, Joost; van den Hurk, Katja; Baart, Mireille; Hoekstra, Trynke; Rizopoulos, Dimitris; Lesaffre, Emmanuel; de Kort, Wim

    2015-01-01

    A too short recovery time after blood donation results in a gradual depletion of iron stores and a subsequent decline in hemoglobin (Hb) levels over time. This decline in Hb levels may depend on individual, unobserved characteristics of the donor. We used a data set of 5388 Dutch blood donors from

  1. Photoacoustic microscopy of cerebral hemodynamic and oxygen-metabolic responses to anesthetics

    Science.gov (United States)

    Cao, Rui; Li, Jun; Ning, Bo; Sun, Naidi; Wang, Tianxiong; Zuo, Zhiyi; Hu, Song

    2017-02-01

    General anesthetics are known to have profound effects on cerebral hemodynamics and neuronal activities. However, it remains a challenge to directly assess anesthetics-induced hemodynamic and oxygen-metabolic changes from the true baseline under wakefulness at the microscopic level, due to the lack of an enabling technology for high-resolution functional imaging of the awake mouse brain. To address this challenge, we have developed head-restrained photoacoustic microscopy (PAM), which enables simultaneous imaging of the cerebrovascular anatomy, total concentration and oxygen saturation of hemoglobin (CHb and sO2), and blood flow in awake mice. From these hemodynamic measurements, two important metabolic parameters, oxygen extraction fraction (OEF) and the cerebral metabolic rate of oxygen (CMRO2), can be derived. Side-by-side comparison of the mouse brain under wakefulness and anesthesia revealed multifaceted cerebral responses to isoflurane, a volatile anesthetic widely used in preclinical research and clinical practice. Key observations include elevated cerebral blood flow (CBF) and reduced oxygen extraction and metabolism.

  2. Restoration of blood 2,3-diphosphoglycerate levels in multi-transfused patients: effect of organic and inorganic phosphate.

    Science.gov (United States)

    Iapichino, G; Radrizzani, D; Solca, M; Franzosi, M G; Pallavicini, F B; Spina, G; Scherini, A

    1984-01-01

    Blood stored in acid-citrate-dextrose (ACD) shows a progressive decrease in 2,3-diphosphoglycerate (DPG) content. Since the decrease in DPG increases hemoglobin oxygen affinity, which in turn may reduce tissue and venous PO2 and peripheral oxygen delivery, many efforts have been made to preserve or restore DPG levels in stored blood. An in vivo rejuvenating technique, employing fructose-1,6-diphosphate (FDP) at a mean dosage of 1 mmol kg-1 day-1 of phosphate, to increase the DPG circulating level in multi-transfused patients is proposed. Eighteen patients, who received at least one-third of their estimated blood volume (3990 +/- 480 (SEM) ml of ACD stored blood) in blood transfusion, were treated: nine with inorganic phosphate, and nine with FDP. Basal DPG was very low in both groups: 12.61 +/- 1.34 (SEM) and 10.42 +/- 0.98 (SEM) mumol g-1, respectively (normal value is 14.5 mumol g-1, at pH 7.40). However, DPG values increased significantly and promptly in patients receiving FDP, whereas in cases of inorganic phosphate administration, it was not significantly raised over the basal value until the third day. Phosphatemia remained normal and constant with FDP, but it rose significantly on the third day of treatment with inorganic phosphate. FDP appears to consistently and rapidly increase DPG levels after transfusion with blood stored in ACD, and to be particularly safe.

  3. Toward functional imaging using the optoacoustic 3D whole-body tomography system

    Science.gov (United States)

    Su, R.; Brecht, H.-P.; Ermilov, S. A.; Nadvoretsky, V.; Conjusteau, A.; Oraevsky, A. A.

    2010-02-01

    In this report we demonstrate improved three-dimensional optoacoustic tomography in test samples. High quality tomographic data and images were obtained from phantom of mice being 2.5 cm in diameter. Capillaries filled with cupric sulfate, ferrous sulfate and nickel sulfate solutions, and immersed in a scattering medium were used for these tests. The brightness of reconstructed phantom images was found to match accurately the absorption profiles of test solutions. Hence, optoacoustic imaging can be applied in preclinical research to perform in vivo absorptivity measurements to deduce functional information on blood oxygen levels or concentration of contrast agents.

  4. Novel route synthesis of porous and solid gold nanoparticles for investigating their comparative performance as contrast agent in computed tomography scan and effect on liver and kidney function.

    Science.gov (United States)

    Aziz, Farooq; Ihsan, Ayesha; Nazir, Aalia; Ahmad, Ishaq; Bajwa, Sadia Zafar; Rehman, Asma; Diallo, Abdoulaye; Khan, Waheed S

    2017-01-01

    Gold nanoparticles (GNPs) with dimension in the range of 1-100 nm have a prominent role in a number of biomedical applications like imaging, drug delivery, and cancer therapy owing to their unique optical features and biocompatibility. In this work, we report a novel technique for the synthesis of two types of GNPs namely porous gold nanoparticles (PGNPs) and solid gold nanoparticles (SGNPs). PGNPs of size 35 nm were fabricated by reduction of gold (III) solution with lecithin followed by addition of L-ascorbic acid and tri-sodium citrate, whereas SGNPs with a dimension of 28 nm were prepared by reflux method using lecithin as a single reducing agent. Comparative studies using PGNPs (λ max 560 nm) and SGNPs (λ max 548 nm) were conducted for evaluating their use as a contrast agent. These studies reveled that in direct computed tomography scan, PGNPs exhibited brighter contrast (45 HU) than SGNPs (26 HU). To investigate the effect of PGNPs and SGNPs on the liver and kidney profile, male rabbits were intravenously injected with an equal dose of 1 mg/kg weight of PGNPs and SGNPs. The effect on biochemical parameters was evaluated 72 hours after intravenous (IV) injection including liver function profile, renal (kidney) function biomarker, random blood glucose value, and cholesterol level. During one comparison of contrast in CT scan, PGNPs showed significantly enhanced contrast in whole-rabbit and organ CT scan as compared to SGNPs 6 hours after injection. Our findings suggested that the novel PGNPs enhance CT scan image with higher efficacy as compared to SGNPs. The results showed that IV administration of synthesized PGNPs increases the levels of aspartate aminotransferase (AST), alkaline phosphate (ALP), serum creatinine, and blood glucose, whereas that of SGNPs increases the levels of AST, ALP, and blood glucose.

  5. Metabolism of the intervertebral disc: effects of low levels of oxygen, glucose, and pH on rates of energy metabolism of bovine nucleus pulposus cells.

    Science.gov (United States)

    Bibby, Susan R S; Jones, Deborah A; Ripley, Ruth M; Urban, Jill P G

    2005-03-01

    In vitro measurements of metabolic rates of isolated bovine nucleus pulposus cells at varying levels of oxygen, glucose, and pH. To obtain quantitative information on the interactions between oxygen and glucose concentrations and pH, and the rates of oxygen and glucose consumption and lactic acid production, for disc nucleus cells. Disc cells depend on diffusion from blood vessels at the disc margins for supply of nutrients. Loss of supply is thought to lead to disc degeneration, but how loss of supply affects nutrient concentrations in the disc is not known; nutrient concentrations within discs can normally only be calculated, because concentration measurements are invasive. However, realistic predictions cannot be made until there are data from measurements of metabolic rates at conditions found in the disc in vivo, i.e., at low levels of oxygen, glucose, and pH. A metabolism chamber was designed to allow simultaneous recording of oxygen and glucose concentrations and of pH. These concentrations were measured electrochemically with custom-built glucose and oxygen sensors; lactic acid was measured biochemically. Bovine nucleus pulposus cells were isolated and inserted into the chamber, and simultaneous rates of oxygen and glucose consumption and of lactic acid production were measured over a range of glucose, oxygen, and pH levels. There were strong interactions between rates of metabolism and oxygen consumption and pH. At atmospheric oxygen levels, oxygen consumption rate at pH 6.2 was 32% of that at pH 7.4. The rate fell by 60% as oxygen concentration was decreased from 21 to 5% at pH 7.4, but only by 20% at pH 6.2. Similar interactions were seen for lactic acid production and glucose consumption rates; we found that glycolysis rates fell at low oxygen and glucose concentrations and low pH. Equations were derived that satisfactorily predict the effect of nutrient and metabolite concentrations on rates of lactic acid production rate and oxygen consumption. Disc

  6. Experimental studies of renal blood flow by digitized functional angiography

    International Nuclear Information System (INIS)

    Buersch, J.H.; Ochs, C.; Hahne, H.J.; Heintzen, P.H.

    1985-01-01

    New techniques of digital image processing have been experimentally tested for the assessment of renal blood flow. The underlying principle in functional angiography is the extraction of flow parameters. Basically, density-time variations of the contrast medium are analayzed from to each picture element of a 256x256 matrix. The real-time acquisition rate of images was 25/sec. For the calculation of angiographic flow a PDP 11/40 computer was used to interactively perform a time dependent segmentation of the renal arteries and the aorta. Subsequently, volume flow was calculated in relative units for the specific vascular segments under study. 15 control angiograms were made in 5 animals with cardiac output ranging between 0.8 to 2.2l/min. Unilateral renal blood flow was calculated as 24+-3.4% of pre-renal aortic flow without systematic side differences. Reproducibility from repeated flow measurements showed an SD of +-1.8% of the individual pre-renal aortic flow. Renal flow was also measured in 3 animals with an experimentally created 50% flow reduction of the left kidney. Angiographic flow in the left renal artery dropped to 12+-2% of pre-renal flow. The present experimental data suggest that digital angiography has sufficient diagnostic capabilities for the detection of abnormal renal blood flow. The technique may serve as a useful diagnostic adjunct to conventional angiography and has the potential of assisting in the evaluation of renal vascular hypertension. (orig.) [de

  7. Non-invasive estimation of blood pressure using ultrasound contrast agents

    DEFF Research Database (Denmark)

    Andersen, Klaus Scheldrup; Jensen, Jørgen Arendt

    2009-01-01

    Local blood pressure measurements provide important information on the state of health of organs in the body and can be used to diagnose diseases in the heart, lungs, and kidneys. This paper presents an experimental setup for investigating the ambient pressure sensitivity of a contrast agent using...

  8. Small molecule CP-31398 induces reactive oxygen species-dependent apoptosis in human multiple myeloma.

    Science.gov (United States)

    Arihara, Yohei; Takada, Kohichi; Kamihara, Yusuke; Hayasaka, Naotaka; Nakamura, Hajime; Murase, Kazuyuki; Ikeda, Hiroshi; Iyama, Satoshi; Sato, Tsutomu; Miyanishi, Koji; Kobune, Masayoshi; Kato, Junji

    2017-09-12

    Reactive oxygen species (ROS) are normal byproducts of a wide variety of cellular processes. ROS have dual functional roles in cancer cell pathophysiology. At low to moderate levels, ROS act as signaling transducers to activate cell proliferation, migration, invasion, and angiogenesis. In contrast, high levels of ROS induce cell death. In multiple myeloma (MM), ROS overproduction is the trigger for apoptosis induced by several anticancer compounds, including proteasome inhibitors. However, no drugs for which oxidative stress is the main mechanism of action are currently used for treatment of MM in clinical situations. In this study, we demonstrate that the p53-activating small molecule CP-31398 (CP) effectively inhibits the growth of MM cell lines and primary MM isolates from patients. CP also suppresses the growth of MM xenografts in mice. Mechanistically, CP was found to induce intrinsic apoptosis in MM cells via increasing ROS production. Interestingly, CP-induced apoptosis occurs regardless of the p53 status, suggesting that CP has additional mechanisms of action. Our findings thus indicate that CP could be an attractive candidate for treatment of MM patients harboring p53 abnormalities; this satisfies an unmet clinical need, as such individuals currently have a poor prognosis.

  9. Differential signal pathway activation and 5-HT function: the role of gut enterochromaffin cells as oxygen sensors.

    Science.gov (United States)

    Haugen, Martin; Dammen, Rikard; Svejda, Bernhard; Gustafsson, Bjorn I; Pfragner, Roswitha; Modlin, Irvin; Kidd, Mark

    2012-11-15

    The chemomechanosensory function of the gut enterochromaffin (EC) cell enables it to respond to dietary agents and mechanical stretch. We hypothesized that the EC cell, which also sensed alterations in luminal or mucosal oxygen level, was physiologically sensitive to fluctuations in O(2). Given that low oxygen levels induce 5-HT production and secretion through a hypoxia inducible factor 1α (HIF-1α)-dependent pathway, we also hypothesized that increasing O(2) would reduce 5-HT production and secretion. Isolated normal EC cells as well as the well-characterized EC cell model KRJ-I were used to examine HIF signaling (luciferase-assays), hypoxia transcriptional response element (HRE)-mediated transcription (PCR), signaling pathways (Western blot), and 5-HT release (ELISA) during exposure to different oxygen levels. Normal EC cells and KRJ-I cells express HIF-1α, and transient transfection with Renilla luciferase under HRE control identified a hypoxia-mediated pathway in these cells. PCR confirmed activation of HIF-downstream targets, GLUT1, IGF2, and VEGF under reduced O(2) levels (0.5%). Reducing O(2) also elevated 5-HT secretion (2-3.2-fold) as well as protein levels of HIF-1α (1.7-3-fold). Increasing O(2) to 100% inhibited HRE-mediated signaling, transcription, reduced 5-HT secretion, and significantly lowered HIF-1α levels (∼75% of control). NF-κB signaling was also elevated during hypoxia (1.2-1.6-fold), but no significant changes were noted in PKA/cAMP. We concluded that gut EC cells are oxygen responsive, and alterations in O(2) levels differentially activate HIF-1α and tryptophan hydroxylase 1, as well as NF-κB signaling. This results in alterations in 5-HT production and secretion and identifies that the chemomechanosensory role of EC cells extends to oxygen sensing.

  10. Functional BOLD MRI: comparison of different field strengths in a motor task

    International Nuclear Information System (INIS)

    Meindl, T.; Born, C.; Britsch, S.; Reiser, M.; Schoenberg, S.

    2008-01-01

    The purpose was to evaluate the benefit of an increased field strength for functional magnetic resonance imaging in a motor task. Six right-handed volunteers were scanned at 1.5 T and 3.0 T using a motor task. Each experiment consisted of two runs with four activation blocks, each with right- and left-hand tapping. Analysis was done using BrainVoyagerQX registered . Differences between both field strengths concerning signal to noise (SNR), blood oxygen level-dependent (BOLD) signal change, functional sensitivity and BOLD contrast to noise (CNR) were tested using a paired t test. Delineation of activations and artifacts were graded by two independent readers. Results were further validated by means of a phantom study. The sensorimotor and premotor cortex, the supplementary motor area, subcortical and cerebellar structures were activated at each field strength. Additional activations of the right premotor cortex and right superior temporal gyrus were found at 3.0 T. Signal-to-noise, percentage of BOLD signal change, BOLD CNR and functional sensitivity improved at 3.0 T by a factor of up to 2.4. Functional imaging at 3.0 T results in detection of additional activated areas, increased SNR, BOLD signal change, functional sensitivity and BOLD CNR. (orig.)

  11. Identification and adjustment of experimental occlusal interference using functional magnetic resonance imaging

    OpenAIRE

    Oda, Masafumi; Yoshino, Kenichi; Tanaka, Tatsurou; Shiiba, Shunji; Makihara, Eri; Miyamoto, Ikuya; Nogami, Shinnosuke; Kito, Shinji; Wakasugi-Sato, Nao; Matsumoto-Takeda, Shinobu; Nishimura, Shun; Murakami, Keita; Koga, Masahiro; Kawagishi, Shigenori; Yoshioka, Izumi

    2014-01-01

    Background The purpose of this study was to use functional magnetic resonance imaging (fMRI) to quantify changes in brain activity during experimental occlusal interference. Methods Fourteen healthy volunteers performed a rhythmical tapping occlusion task with experimental occlusal interference of the right molar tooth at 0 mm (no occlusion), 0.5 mm, and 0.75 mm. The blood-oxygen-level dependent (BOLD) signal was quantified using statistical parametric mapping and compared between rest period...

  12. Image-Based Modeling of Blood Flow and Oxygen Transfer in Feto-Placental Capillaries.

    Directory of Open Access Journals (Sweden)

    Philip Pearce

    Full Text Available During pregnancy, oxygen diffuses from maternal to fetal blood through villous trees in the placenta. In this paper, we simulate blood flow and oxygen transfer in feto-placental capillaries by converting three-dimensional representations of villous and capillary surfaces, reconstructed from confocal laser scanning microscopy, to finite-element meshes, and calculating values of vascular flow resistance and total oxygen transfer. The relationship between the total oxygen transfer rate and the pressure drop through the capillary is shown to be captured across a wide range of pressure drops by physical scaling laws and an upper bound on the oxygen transfer rate. A regression equation is introduced that can be used to estimate the oxygen transfer in a capillary using the vascular resistance. Two techniques for quantifying the effects of statistical variability, experimental uncertainty and pathological placental structure on the calculated properties are then introduced. First, scaling arguments are used to quantify the sensitivity of the model to uncertainties in the geometry and the parameters. Second, the effects of localized dilations in fetal capillaries are investigated using an idealized axisymmetric model, to quantify the possible effect of pathological placental structure on oxygen transfer. The model predicts how, for a fixed pressure drop through a capillary, oxygen transfer is maximized by an optimal width of the dilation. The results could explain the prevalence of fetal hypoxia in cases of delayed villous maturation, a pathology characterized by a lack of the vasculo-syncytial membranes often seen in conjunction with localized capillary dilations.

  13. Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

    Energy Technology Data Exchange (ETDEWEB)

    Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

    2015-07-15

    Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

  14. [Effect of different oxygen concentrations on biological properties of bone marrow hematopoietic stem cells of mice].

    Science.gov (United States)

    Ma, Yi-Ran; Ren, Si-Hua; He, Yu-Xin; Wang, Lin-Lin; Jin, Li; Hao, Yi-Wen

    2012-10-01

    This study purposed to investigate the effects of different oxygen concentrations and reactive oxygen species (ROS) on the biological characteristics of hematopoietic stem cells (HSC) and their possible mechanisms through simulating oxygen environment to which the peripheral blood HSC are subjected in peripheral blood HSCT. The proliferation ability, cell cycle, directed differentiation ability, ROS level and hematopoietic reconstitution ability of Lin(-)c-kit(+)Sca-1(+) BMHSC were detected by using in vitro amplification test, directional differentiation test, cell cycle analysis, ROS assay and transplantation of Lin(-)c-kit(+)Sca-1(+) HSC from sublethally irradiated mice respectively. The results showed that oxygen concentrations lower than normal oxygen concentration, especially in hypoxic oxygen environment, could reduce ROS generation and amplify more primitive CD34(+)AC133(+) HSC and active CD34(+) HSC, and maintain more stem cells in the G(0)/G(1) phase, which is more helpful to the growth of CFU-S and viability of mice. At the same time, BMHSC exposed to normal oxygen level or inconstant and greatly changed oxygen concentrations could produce a high level of ROS, and the above-mentioned features and functional indicators are relatively low. It is concluded that ROS levels of HSC in BMHSCT are closely related with the oxygen concentration surrounding the cells and its stability. Low oxygen concentration and antioxidant intervention are helpful to transplantation of BMHSC.

  15. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    International Nuclear Information System (INIS)

    Sedlacik, Jan; Fiehler, Jens; Reitz, Matthias; Schmidt, Nils O.; Bolar, Divya S.; Adalsteinsson, Elfar

    2015-01-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s and -1] = 20.7/20.4/20.1, R2*[s and -1] = 31.6/29.6/25.9, R2'[s and 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min and -1.100g and -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood oxygenation level. We found good

  16. Correlation of oxygenation and perfusion sensitive MRI with invasive micro probe measurements in healthy mice brain

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacik, Jan; Fiehler, Jens [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neuroradiology; Reitz, Matthias; Schmidt, Nils O. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Neurosurgery; Bolar, Divya S. [Massachusetts General Hospital, Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA (United States). Radiology; Adalsteinsson, Elfar [Massachusetts Institute of Technology, Cambridge, MA (United States). Electrical Engineering and Computer Science

    2015-05-01

    The non-invasive assessment of (patho-)physiological parameters such as, perfusion and oxygenation, is of great importance for the characterization of pathologies e.g., tumors, which may be helpful to better predict treatment response and potential outcome. To better understand the influence of physiological parameters on the investigated oxygenation and perfusion sensitive MRI methods, MRI measurements were correlated with subsequent invasive micro probe measurements during free breathing conditions of air, air+10% CO2 and 100% O2 in healthy mice brain. MRI parameters were the irreversible (R2), reversible (R2') and effective (R2*) transverse relaxation rates, venous blood oxygenation level assessed by quantitative blood oxygenation level dependent (qBOLD) method and cerebral blood flow (CBF) assessed by arterial spin labeling (ASL) using a 7T small animal MRI scanner. One to two days after MRI, tissue perfusion and pO2 were measured by Laser-Doppler flowmetry and fluorescence quenching micro probes, respectively. The tissue pO2 values were converted to blood oxygen saturation by using the Hill equation. The animals were anesthetized by intra peritoneal injection of ketamine-xylazine-acepromazine (10-2-0.3 mg/ml.kg). Results for normal/hypercapnia/hyperoxia conditions were: R2[s {sup and} -1] = 20.7/20.4/20.1, R2*[s {sup and} -1] = 31.6/29.6/25.9, R2'[s {sup and} 1] = 10.9/9.2/5.7, qBOLD venous blood oxygenation level = 0.43/0.51/0.56, CBF[ml.min {sup and} -1.100g {sup and} -1] = 70.6/105.5/81.8, Laser-Doppler flowmetry[a.u.] = 89.2/120.2/90.6 and pO2[mmHg] = 6.3/32.3/46.7. All parameters were statistically significantly different with P < 0.001 between all breathing conditions. All MRI and the corresponding micro probe measurements were also statistically significantly (P ≤ 0.03) correlated with each other. However, converting the tissue pO2 to blood oxygen saturation = 0.02/0.34/0.63, showed only very limited agreement with the qBOLD venous blood

  17. Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

    Energy Technology Data Exchange (ETDEWEB)

    Ogami, M; Kulkarni, R; Wang, H; Reif, R; Wang, R K [University of Washington, Department of Bioengineering, Seattle, Washington 98195 (United States)

    2014-08-31

    We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing. (laser biophotonics)

  18. Laser speckle contrast imaging of skin blood perfusion responses induced by laser coagulation

    Science.gov (United States)

    Ogami, M.; Kulkarni, R.; Wang, H.; Reif, R.; Wang, R. K.

    2014-08-01

    We report application of laser speckle contrast imaging (LSCI), i.e., a fast imaging technique utilising backscattered light to distinguish such moving objects as red blood cells from such stationary objects as surrounding tissue, to localise skin injury. This imaging technique provides detailed information about the acute perfusion response after a blood vessel is occluded. In this study, a mouse ear model is used and pulsed laser coagulation serves as the method of occlusion. We have found that the downstream blood vessels lacked blood flow due to occlusion at the target site immediately after injury. Relative flow changes in nearby collaterals and anastomotic vessels have been approximated based on differences in intensity in the nearby collaterals and anastomoses. We have also estimated the density of the affected downstream vessels. Laser speckle contrast imaging is shown to be used for highresolution and fast-speed imaging for the skin microvasculature. It also allows direct visualisation of the blood perfusion response to injury, which may provide novel insights to the field of cutaneous wound healing.

  19. The contribution of astrocytes to the regulation of cerebral blood flow

    Directory of Open Access Journals (Sweden)

    Clare eHowarth

    2014-05-01

    Full Text Available In order to maintain normal brain function, it is critical that cerebral blood flow (CBF is matched to neuronal metabolic needs. Accordingly, blood flow is increased to areas where neurons are more active (a response termed functional hyperemia. The tight relationships between neuronal activation, glial cell activity, cerebral energy metabolism and the cerebral vasculature, known as neurometabolic and neurovascular coupling, underpin functional MRI (fMRI signals but are incompletely understood. As functional imaging techniques, particularly BOLD fMRI, become more widely used, their utility hinges on our ability to accurately and reliably interpret the findings. A growing body of data demonstrates that astrocytes can serve as a ‘bridge’, relaying information on the level of neural activity to blood vessels in order to coordinate oxygen and glucose delivery with the energy demands of the tissue. It is widely assumed that calcium-dependent release of vasoactive substances by astrocytes results in arteriole dilation and the increased blood flow which accompanies neuronal activity. However, the signaling molecules responsible for this communication between astrocytes and blood vessels are yet to be definitively confirmed. Indeed, there is controversy over whether activity-induced changes in astrocyte calcium are widespread and fast enough to elicit such functional hyperemia responses. In this review, I will summarise the evidence which has convincingly demonstrated that astrocytes are able to modify the diameter of cerebral arterioles. I will discuss the prevalence, presence and timing of stimulus-induced astrocyte calcium transients and describe the evidence for and against the role of calcium-dependent formation and release of vasoactive substances by astrocytes. I will also review alternative mechanisms of astrocyte-evoked changes in arteriole diameter and consider the questions which remain to be answered in this exciting area of research.

  20. BOLD magnetic resonance imaging in nephrology

    Science.gov (United States)

    Hall, Michael E; Jordan, Jennifer H; Juncos, Luis A; Hundley, W Gregory; Hall, John E

    2018-01-01

    Magnetic resonance (MR) imaging, a non-invasive modality that provides anatomic and physiologic information, is increasingly used for diagnosis of pathophysiologic conditions and for understanding renal physiology in humans. Although functional MR imaging methods were pioneered to investigate the brain, they also offer powerful techniques for investigation of other organ systems such as the kidneys. However, imaging the kidneys provides unique challenges due to potential complications from contrast agents. Therefore, development of non-contrast techniques to study kidney anatomy and physiology is important. Blood oxygen level-dependent (BOLD) MR is a non-contrast imaging technique that provides functional information related to renal tissue oxygenation in various pathophysiologic conditions. Here we discuss technical considerations, clinical uses and future directions for use of BOLD MR as well as complementary MR techniques to better understand renal pathophysiology. Our intent is to summarize kidney BOLD MR applications for the clinician rather than focusing on the complex physical challenges that functional MR imaging encompasses; however, we briefly discuss some of those issues. PMID:29559807

  1. Association between intraoperative tissue oxygenation, arterial blood pressure and noradrenaline use in urological patients

    NARCIS (Netherlands)

    Spruit, R.J.; Schwarte, L.A.; Hakenberg, O.W.; Scheeren, T.

    2011-01-01

    Background and Goal of Study: Inadequate tissue oxygenation should be prevented during surgery as it might cause postoperative morbidity. In this observational study we looked at factors that might influence tissue oxygenation (StO2) such as blood pressure and use of vasoactive drugs. Materials and

  2. Effects of end-stage renal disease and dialysis modalities on blood ammonia level.

    Science.gov (United States)

    Vaziri, Nosratola D; Khazaeli, Mahyar; Nunes, Ane C F; Harley, Kevin T; Said, Hyder; Alipour, Omeed; Lau, Wei Ling; Pahl, Madeleine V

    2017-07-01

    Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. © 2016 International Society for Hemodialysis.

  3. Nanotoxic Profiling of Novel Iron Oxide Nanoparticles Functionalized with Perchloric Acid and SiPEG as a Radiographic Contrast Medium

    Directory of Open Access Journals (Sweden)

    Muhamad Idham Mohamed

    2015-01-01

    Full Text Available Emerging syntheses and findings of new metallic nanoparticles (MNPs have become an important aspect in various fields including diagnostic imaging. To date, iodine has been utilized as a radiographic contrast medium. However, the raise concern of iodine threats on iodine-intolerance patient has led to search of new contrast media with lower toxic level. In this animal modeling study, 14 nm iron oxide nanoparticles (IONPs with silane-polyethylene glycol (SiPEG and perchloric acid have been assessed for toxicity level as compared to conventional iodine. The nanotoxicity of IONPs was evaluated in liver biochemistry, reactive oxygen species production (ROS, lipid peroxidation mechanism, and ultrastructural evaluation using transmission electron microscope (TEM. The hematological analysis and liver function test (LFT revealed that most of the liver enzymes were significantly higher in iodine-administered group as compared to those in normal and IONPs groups P<0.05. ROS production assay and lipid peroxidation indicator, malondialdehyde (MDA, also showed significant reductions in comparison with iodine group P<0.05. TEM evaluation yielded the aberration of nucleus structure of iodine-administered group as compared to those in control and IONPs groups. This study has demonstrated the less toxic properties of IONPs and it may postulate that IONPs are safe to be applied as radiographic contrast medium.

  4. Cerebral blood oxygenation measurements in neonates with optoacoustic technique

    Science.gov (United States)

    Herrmann, Stephen; Petrov, Irene Y.; Petrov, Yuriy; Richardson, C. Joan; Fonseca, Rafael A.; Prough, Donald S.; Esenaliev, Rinat O.

    2017-03-01

    Cerebral hypoxia is a major contributor to neonatal/infant mortality and morbidity including severe neurological complications such as mental retardation, cerebral palsy, motor impairment, and epilepsy. Currently, no technology is capable of accurate monitoring of neonatal cerebral oxygenation. We proposed to use optoacoustics for this application by probing the superior sagittal sinus (SSS), a large central cerebral vein. We developed and built a multi-wavelength, optical parametric oscillator (OPO) and laser diode optoacoustic systems for measurement of SSS blood oxygenation in the reflection mode through open anterior or posterior fontanelles and in the transmission mode through the skull in the occipital area. In this paper we present results of initial tests of the laser diode system for neonatal cerebral oxygenation measurements. First, the system was tested in phantoms simulating neonatal SSS. Then, using the data obtained in the phantoms, we optimized the system's hardware and software and tested it in neonates admitted in the Neonatal Intensive Care Unit. The laser diode system was capable of detecting SSS signals in the reflection mode through the open anterior and posterior fontanelles as well as in the transmission mode through the skull with high signal-to-noise ratio. Using the signals measured at different wavelengths and algorithms developed for oxygenation measurements, the laser diode system provided real-time, continuous oxygenation monitoring with high precision at all these locations.

  5. Contrasting characteristics of sub-microsecond pulsed atmospheric air and atmospheric pressure helium-oxygen glow discharges

    International Nuclear Information System (INIS)

    Walsh, J L; Liu, D X; Iza, F; Kong, M G; Rong, M Z

    2010-01-01

    Glow discharges in air are often considered to be the ultimate low-temperature atmospheric pressure plasmas for numerous chamber-free applications. This is due to the ubiquitous presence of air and the perceived abundance of reactive oxygen and nitrogen species in air plasmas. In this paper, sub-microsecond pulsed atmospheric air plasmas are shown to produce a low concentration of excited oxygen atoms but an abundance of excited nitrogen species, UV photons and ozone molecules. This contrasts sharply with the efficient production of excited oxygen atoms in comparable helium-oxygen discharges. Relevant reaction chemistry analysed with a global model suggests that collisional excitation of O 2 by helium metastables is significantly more efficient than electron dissociative excitation of O 2 , electron excitation of O and ion-ion recombination. These results suggest different practical uses of the two oxygen-containing atmospheric discharges, with air plasmas being well suited for nitrogen and UV based chemistry and He-O 2 plasmas for excited atomic oxygen based chemistry. (fast track communication)

  6. The dual roles of red blood cells in tissue oxygen delivery

    DEFF Research Database (Denmark)

    Jensen, Frank Bo

    2009-01-01

    Vertebrate red blood cells (RBCs) seem to serve tissue oxygen delivery in two distinct ways. Firstly, RBCs enable the adequate transport of O2 between respiratory surfaces and metabolizing tissues by means of their high intracellular concentration of hemoglobin (Hb), appropriate allosteric...

  7. Effects of Hemoglobin-Based Oxygen Carriers on Blood Coagulation

    Directory of Open Access Journals (Sweden)

    Kimia Roghani

    2014-12-01

    Full Text Available For many decades, Hemoglobin-based oxygen carriers (HBOCs have been central in the development of resuscitation agents that might provide oxygen delivery in addition to simple volume expansion. Since 80% of the world population lives in areas where fresh blood products are not available, the application of these new solutions may prove to be highly beneficial (Kim and Greenburg 2006. Many improvements have been made to earlier generation HBOCs, but various concerns still remain, including coagulopathy, nitric oxide scavenging, platelet interference and decreased calcium concentration secondary to volume expansion (Jahr et al. 2013. This review will summarize the current challenges faced in developing HBOCs that may be used clinically, in order to guide future research efforts in the field.

  8. Blood Transfusion Strategies in Patients Undergoing Extracorporeal Membrane Oxygenation

    Directory of Open Access Journals (Sweden)

    Hyoung Soo Kim

    2017-02-01

    Full Text Available Extracorporeal membrane oxygenation (ECMO is frequently associated with bleeding and coagulopathy complications, which may lead to the need for transfusion of multiple blood products. However, blood transfusions are known to increase morbidity and mortality, as well as hospital cost, in critically ill patients. In current practice, patients on ECMO receive a transfusion, on average, of 1-5 packed red blood cells (RBCs/day, with platelet transfusion accounting for the largest portion of transfusion volume. Generally, adult patients require more transfusions than neonates or children, and patients receiving venovenous ECMO for respiratory failure tend to need smaller transfusion volumes compared to those receiving venoarterial ECMO for cardiac failure. Observation studies have reported that a higher transfusion volume was associated with increased mortality. To date, the evidence for transfusion in patients undergoing ECMO is limited; most knowledge on transfusion strategies was extrapolated from studies in critically ill patients. However, current data support a restrictive blood transfusion strategy for ECMO patients, and a low transfusion trigger seems to be safe and reasonable.

  9. Open label smoking cessation with varenicline is associated with decreased glutamate levels and functional changes in anterior cingulate cortex: preliminary findings

    Directory of Open Access Journals (Sweden)

    Muriah Dawn Wheelock

    2014-07-01

    Full Text Available Rationale: Varenicline, the most effective single agent for smoking cessation, is a partial agonist at α4β2 nicotinic acetylcholine receptors. Increasing evidence implicates glutamate in the pathophysiology of addiction and one of the benefits of treatment for smoking cessation is the ability to regain cognitive control. Objective: To evaluate the effects of 12 week varenicline administration on glutamate levels in the dorsal anterior cingulate cortex (dACC and functional changes within the cognitive control network.Methods: We used single-voxel proton magnetic resonance spectroscopy (1H-MRS in the dACC and functional MRI (fMRI during performance of a Stroop color-naming task before and after smoking cessation with varenicline in 11 healthy smokers (open label design. Using the dACC as a seed region, we evaluated functional connectivity changes using a psychophysiological interaction (PPI analysis. Results: We observed a significant decrease in dACC glutamate + glutamine (Glx/Cr levels as well as significant blood oxygen level-dependent signal (BOLD decreases in the rostral ACC/medial orbitofrontal cortex and precuneus/posterior cingulate cortex. These BOLD changes are suggestive of alterations in default mode network (DMN function and are further supported by the results of the PPI analysis that revealed changes in connectivity between the dACC and regions of the DMN. Baseline measures of nicotine dependence and craving positively correlated with baseline Glx/Cr levels.Conclusions: These results suggest possible mechanisms of action for varenicline such as reduction in Glx levels in dACC and shifts in BOLD activities between large scale brain networks. They also suggest a role for ACC Glx in the modulation of behavior. Due to the preliminary nature of this study (lack of control group and small sample size, future studies are needed to replicate these findings.

  10. Functional brain imaging in irritable bowel syndrome with rectal balloon-distention by using fMRI

    OpenAIRE

    Yuan, Yao-Zong; Tao, Ran-Jun; Xu, Bin; Sun, Jing; Chen, Ke-Min; Miao, Fei; Zhang, Zhong-Wei; Xu, Jia-Yu

    2003-01-01

    AIM: Irritable bowel syndrome (IBS) is characterized by abdominal pain and changes in stool habits. Visceral hypersensitivity is a key factor in the pathophysiology of IBS. The aim of this study was to examine the effect of rectal balloon-distention stimulus by blood oxygenation level-dependent functional magnetic resonance imaging (BOLD-fMRI) in visceral pain center and to compare the distribution, extent, and intensity of activated areas between IBS patients and normal controls.

  11. Atomic Oxygen Erosion Yield Dependence Upon Texture Development in Polymers

    Science.gov (United States)

    Banks, Bruce A.; Loftus, Ryan J.; Miller, Sharon K.

    2016-01-01

    The atomic oxygen erosion yield (volume of a polymer that is lost due to oxidation per incident atom) of polymers is typically assumed to be reasonably constant with increasing fluence. However polymers containing ash or inorganic pigments, tend to have erosion yields that decrease with fluence due to an increasing presence of protective particles on the polymer surface. This paper investigates two additional possible causes for erosion yields of polymers that are dependent upon atomic oxygen. These are the development of surface texture which can cause the erosion yield to change with fluence due to changes in the aspect ratio of the surface texture that develops and polymer specific atomic oxygen interaction parameters. The surface texture development under directed hyperthermal attack produces higher aspect ratio surface texture than isotropic thermal energy atomic oxygen attack. The fluence dependence of erosion yields is documented for low Kapton H (DuPont, Wilmington, DE) effective fluences for a variety of polymers under directed hyperthermal and isotropic thermal energy attack.

  12. Betel Leaf Extract (Piper betle L.) Antihyperuricemia Effect Decreases Oxidative Stress by Reducing the Level of MDA and Increase Blood SOD Levels of Hyperuricemia Wistar Rats (Rattus norvegicus)

    OpenAIRE

    I Made Sumarya; Nyoman Adiputra; Putra Manuaba; Dewa Sukrama

    2016-01-01

    Background: Betel leaf extracts (Piper betle L.) antioxidant activity and enzyme inhibitors of XO. Hyperuricemia cause oxidative stress by increasing the formation of reactive oxygen species (ROS) cause lipid peroxidation and oxygenation of low-density lipoprotein cholesterol (LDLc). Objective: The aim of this research was to determine the betel leaf extract as an anti hyperuricemia that can lower the blood uric acid levels and oxidative stress by lowering the levels of MDA and increase the S...

  13. High circulating osteoprotegerin levels are associated with non-zero blood groups.

    Science.gov (United States)

    Nagy, Elod Erno; Varga-Fekete, Timea; Puskas, Attila; Kelemen, Piroska; Brassai, Zoltan; Szekeres-Csiki, Katalin; Gombos, Timea; Csanyi, Maria Csilla; Harsfalvi, Jolan

    2016-05-26

    Osteoprotegerin (OPG) and von Willebrand factor (VWF) form complex within endothelial cells and following secretion. The nature of blood group antigens strongly influences the levels of circulating VWF, but there is no available data concerning its ascendancy on OPG levels. We aimed to assess the relationship of AB0 blood groups with OPG, VWF levels (VWF: Ag) and collagen binding activity (VWF: CB) in peripheral arterial disease (PAD) patients. Functional and laboratory parameters of 105 PAD patients and 109 controls were examined. Results of OPG, VWF: Ag, VWF: CB (ELISA-s) were analysed by comparative statistics, together with clinical data. OPG levels were higher in patients than in controls (4.64 ng/mL vs. 3.68 ng/mL, p blood groups compared to 0-groups both in patients and controls (4.95 ng/mL vs. 3.90 ng/mL, p = 0.012 and 4.09 ng/mL vs. 3.40 ng/mL, p = 0.002). OPG levels are associated to blood group phenotypes and higher in non-0 individuals. Increased OPG levels in PAD characterize disease severity. The significant correlation between OPG and VWF:CB might have functional importance in an atherothrombosis-prone biological environment.

  14. [Immunologic indexes, enzyme status of lymphocytes and functional activity of blood neutrophils in children with infectious mononucleosis caused by Epstein-Barr virus].

    Science.gov (United States)

    Kurtasova, L M; Tolstikova, A E; Savchenko, A A

    2013-01-01

    Explore the immunological parameters, levels of activity of NAD(P)-dependent dehydrogenases lymphocytes, interferon status parameters, phagocytic activity and chemiluminescence response of neutrophils in the blood of children in the acute phase of infectious mononucleosis caused by the Epstein-Barr virus. 65 children at the age of 4-6 years old with infectious mononucleosis caused by EBV in acute phase were observed. Such indexes as cell-mediated, humoral and interferon immunity, NAD(P)-depended dehydrogenases activity in blood lymphocyte, phagocytes activity, levels of spontaneous and induced chemiluminescence ofperipheral blood neutrophils were studied. Children with EVB-infection have immunophenotype spectrum changes and changes of enzymes status of blood lymphocytes against the increasing in leucocytes and the useful increasing in lymphocytes. The useful increasing in IgA, IgM, IgG contenting in serum blood were found. The decreasing of spontaneous production of IFN alpha and the decreasing of induced production of IFNalpha, IFNgamma were determined. The breach of phagocytes activity and chemiluminescent response of blood neutrophils were found. The children in the acute phase of infectious mononucleosis caused by the Epstein-Barr virus, there are changes in the immune status, changes the activity of NAD(P)-dependent dehydrogenases in blood lymphocytes, marked changes in functional and metabolic state of peripheral blood neutrophils.

  15. Na+/Ca2+ exchange inhibitor, KB-R7943, attenuates contrast-induced acute 
kidney injury.

    Science.gov (United States)

    Yang, Dingwei; Yang, Dingping; Jia, Ruhan; Tan, Jin

    2013-01-01

    Intracellular Ca2+ overload is considered to be a key factor in contrast-induced acute kidney injury (CI-AKI). The Na+/Ca2+ exchanger (NCX) system is one of the main pathways of intracellular Ca2+ overload. We investigated the effects of KB-R7943, an inhibitor of the reverse mode of NCX, on CI-AKI in a rat model. Rats were divided into control group, CI-AKI group and pretreatment groups (with KB-R7943 dose of 5 or 10 mg/kg). CI-AKI was induced by diatrizoate administration in rats with cholesterol-supplemented diet for 8 weeks. Renal function and renal hemodynamics were determined 1 day following contrast medium administration. Renal histopathology was observed by light microscope. Renal tubular apoptosis was examined by TUNEL. Renal endothelin-1 (ET-1) was measured by radioimmunoassay. Renal malondialdehyde (MDA) and catalase (CAT) were measured as oxidative markers. Levels of serum creatinine (Scr), renal ET-1, MDA and CAT, and resistance index (RI) of renal blood vessels increased significantly in CI-AKI rats. The 
increases in Scr and RI of renal blood vessels induced by diatrizoate were suppressed significantly and 
dose-dependently by pretreatment with KB-R7943. Histopathological and TUNEL results showed that 
the contrast medium-induced severe renal tubular 
necrosis and apoptosis were significantly and dose-dependently attenuated by KB-R7943. KB-R7943 significantly suppressed the increment of renal ET-1 content and MDA and CAT level induced by contrast medium administration. Activation of the reverse mode of NCX, followed by ET-1 overproduction and increased oxidative stress, seems to play an important role in the pathogenesis of CI-AKI. The inhibitor of the reverse mode of NCX, KB-R7943, has renoprotective effects on CI-AKI.

  16. An algorithm for sensing venous oxygenation using ultrasound-modulated light enhanced by microbubbles

    Science.gov (United States)

    Honeysett, Jack E.; Stride, Eleanor; Deng, Jing; Leung, Terence S.

    2012-02-01

    Near-infrared spectroscopy (NIRS) can provide an estimate of the mean oxygen saturation in tissue. This technique is limited by optical scattering, which reduces the spatial resolution of the measurement, and by absorption, which makes the measurement insensitive to oxygenation changes in larger deep blood vessels relative to that in the superficial tissue. Acousto-optic (AO) techniques which combine focused ultrasound (US) with diffuse light have been shown to improve the spatial resolution as a result of US-modulation of the light signal, however this technique still suffers from low signal-to-noise when detecting a signal from regions of high optical absorption. Combining an US contrast agent with this hybrid technique has been proposed to amplify an AO signal. Microbubbles are a clinical contrast agent used in diagnostic US for their ability to resonate in a sound field: in this work we also make use of their optical scattering properties (modelled using Mie theory). A perturbation Monte Carlo (pMC) model of light transport in a highly absorbing blood vessel containing microbubbles surrounded by tissue is used to calculate the AO signal detected on the top surface of the tissue. An algorithm based on the modified Beer-Lambert law is derived which expresses intravenous oxygen saturation in terms of an AO signal. This is used to determine the oxygen saturation in the blood vessel from a dual wavelength microbubble-contrast AO measurement. Applying this algorithm to the simulation data shows that the venous oxygen saturation is accurately recovered, and this measurement is robust to changes in the oxygenation of the superficial tissue layer.

  17. [Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy].

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning

  18. Monitorization of the effects of spinal anaesthesia on cerebral oxygen saturation in elder patients using near-infrared spectroscopy.

    Science.gov (United States)

    Kusku, Aysegul; Demir, Guray; Cukurova, Zafer; Eren, Gulay; Hergunsel, Oya

    2014-01-01

    Central blockage provided by spinal anaesthesia enables realization of many surgical procedures, whereas hemodynamic and respiratory changes influence systemic oxygen delivery leading to the potential development of series of problems such as cerebral ischemia, myocardial infarction and acute renal failure. This study was intended to detect potentially adverse effects of hemodynamic and respiratory changes on systemic oxygen delivery using cerebral oxymetric methods in patients who underwent spinal anaesthesia. Twenty-five ASA I-II Group patients aged 65-80 years scheduled for unilateral inguinal hernia repair under spinal anaesthesia were included in the study. Following standard monitorization baseline cerebral oxygen levels were measured using cerebral oximetric methods. Standardized Mini Mental Test (SMMT) was applied before and after the operation so as to determine the level of cognitive functioning of the cases. Using a standard technique and equal amounts of a local anaesthetic drug (15mg bupivacaine 5%) intratechal blockade was performed. Mean blood pressure (MBP), maximum heart rate (MHR), peripheral oxygen saturation (SpO2) and cerebral oxygen levels (rSO2) were preoperatively monitored for 60min. Pre- and postoperative haemoglobin levels were measured. The variations in data obtained and their correlations with the cerebral oxygen levels were investigated. Significant changes in pre- and postoperative measurements of haemoglobin levels and SMMT scores and intraoperative SpO2 levels were not observed. However, significant variations were observed in intraoperative MBP, MHR and rSO2 levels. Besides, a correlation between variations in rSO2, MBP and MHR was determined. Evaluation of the data obtained in the study demonstrated that post-spinal decline in blood pressure and also heart rate decreases systemic oxygen delivery and adversely effects cerebral oxygen levels. However, this downward change did not result in deterioration of cognitive functioning

  19. Arterial Levels of Oxygen Stimulate Intimal Hyperplasia in Human Saphenous Veins via a ROS-Dependent Mechanism

    Science.gov (United States)

    Joddar, Binata; Firstenberg, Michael S.; Reen, Rashmeet K.; Varadharaj, Saradhadevi; Khan, Mahmood; Childers, Rachel C.; Zweier, Jay L.; Gooch, Keith J.

    2015-01-01

    Saphenous veins used as arterial grafts are exposed to arterial levels of oxygen partial pressure (pO2), which are much greater than what they experience in their native environment. The object of this study is to determine the impact of exposing human saphenous veins to arterial pO2. Saphenous veins and left internal mammary arteries from consenting patients undergoing coronary artery bypass grafting were cultured ex vivo for 2 weeks in the presence of arterial or venous pO2 using an established organ culture model. Saphenous veins cultured with arterial pO2 developed intimal hyperplasia as evidenced by 2.8-fold greater intimal area and 5.8-fold increase in cell proliferation compared to those freshly isolated. Saphenous veins cultured at venous pO2 or internal mammary arteries cultured at arterial pO2 did not develop intimal hyperplasia. Intimal hyperplasia was accompanied by two markers of elevated reactive oxygen species (ROS): increased dihydroethidium associated fluorescence (4-fold, ppO2 is suggested by the observation that chronic exposure to tiron, a ROS scavenger, during the two-week culture period, blocked intimal hyperplasia. Electron paramagnetic resonance based oximetry revealed that the pO2 in the wall of the vessel tracked that of the atmosphere with a ~30 mmHg offset, thus the cells in the vessel wall were directly exposed to variations in pO2. Monolayer cultures of smooth muscle cells isolated from saphenous veins exhibited increased proliferation when exposed to arterial pO2 relative to those cultured at venous pO2. This increased proliferation was blocked by tiron. Taken together, these data suggest that exposure of human SV to arterial pO2 stimulates IH via a ROS-dependent pathway. PMID:25799140

  20. Effects of oxygenation and the stress hormones adrenaline and cortisol on the viscosity of blood from the trout oncorhynchus mykiss

    DEFF Research Database (Denmark)

    Sørensen, Bodil; Weber, Roy

    1995-01-01

    Although the concentrations of the stress hormones adrenaline and cortisol in rainbow trout (Oncorhynchus mykiss) blood increase upon hypoxic exposure, the combined effects of these hormones and O2 lack upon fish blood rheology have not been investigated. Deoxygenated blood taken by caudal puncture...... exhibited lower viscosities than oxygenated samples at low shear rates, whereas the opposite was true at high shear rates. However, blood from cannulated trout had similar viscosities in its deoxygenated and oxygenated states. In the deoxygenated state, addition of adrenaline lowered viscosity at low shear...... rates and increased it at high shear rates, resembling the effects of deoxygenation observed in blood taken by venepuncture. In oxygenated blood on the contrary, no marked adrenaline effects were observed. In deoxygenated blood, addition of cortisol lowered viscosity at all measured shear rates compared...

  1. Primary caregivers of in-home oxygen-dependent children: predictors of stress based on characteristics, needs and social support.

    Science.gov (United States)

    Wang, Kai-Wei K; Lin, Hung-Ching; Lee, Chin-Ting; Lee, Kuo-Sheng

    2016-07-01

    To identify the predictors of primary caregivers' stress in caring for in-home oxygen-dependent children by examining the association between their levels of stress, caregiver needs and social support. Increasing numbers of primary caregivers of oxygen-dependent children experience caregiving stress that warrants investigation. The study used a cross-sectional design with three psychometric scales - Modified-Parenting Stress Index, Caregiver Needs Scale and Social Support Index. The data collected during 2010-2011 were from participants who were responsible for their child's care that included oxygen therapy for ≧6 hours/day; the children's ages ranged from 3 months-16 years. Descriptive statistics and multivariable linear regression were used. A total of 104 participants (M = 34, F = 70) were recruited, with an average age of 39·7 years. The average age of the oxygen-dependent children was 6·68 years and their daily use of oxygen averaged 11·39 hours. The caregivers' overall levels of stress were scored as high and information needs were scored as the highest. The most available support from family and friends was emotional support. Informational support was mostly received from health professionals, but both instrumental and emotional support were important. Levels of stress and caregiver needs were significantly correlated. Multivariable linear regression analyses identified three risk factors predicting stress, namely, the caregiver's poor health status, the child's male gender and the caregiver's greater financial need. To support these caregivers, health professionals can maintain their health status and provide instrumental, emotional, informational and financial support. © 2016 John Wiley & Sons Ltd.

  2. High spatial resolution and high contrast visualization of brain arteries and veins. Impact of blood pool contrast agent and water-selective excitation imaging at 3T

    International Nuclear Information System (INIS)

    Spuentrup, E.; Jacobs, J.E.; Kleimann, J.F.

    2010-01-01

    Purpose: To investigate a blood pool contrast agent and water-selective excitation imaging at 3 T for high spatial and high contrast imaging of brain vessels including the veins. Methods and Results: 48 clinical patients (47 ± 18 years old) were included. Based on clinical findings, twenty-four patients received a single dose of standard extracellular Gadoterate-meglumine (Dotarem registered ) and 24 received the blood pool contrast agent Gadofosveset (Vasovist registered ). After finishing routine MR protocols, all patients were investigated with two high spatial resolution (0.15 mm 3 voxel size) gradient echo sequences in random order in the equilibrium phase (steady-state) as approved by the review board: A standard RF-spoiled gradient-echo sequence (HR-SS, TR/TE 5.1 / 2.3 msec, FA 30 ) and a fat-suppressed gradient-echo sequence with water-selective excitation (HR-FS, 1331 binominal-pulse, TR/TE 8.8 / 3.8 msec, FA 30 ). The images were subjectively assessed (image quality with vessel contrast, artifacts, depiction of lesions) by two investigators and contrast-to-noise ratios (CNR) were compared using the Student's t-test. The image quality and CNR in the HR-FS were significantly superior compared to the HR-SS for both contrast agents (p < 0.05). The CNR was also improved when using the blood pool agent but only to a minor extent while the subjective image quality was similar for both contrast agents. Conclusion: The utilized sequence with water-selective excitation improved image quality and CNR properties in high spatial resolution imaging of brain arteries and veins. The used blood pool contrast agent improved the CNR only to a minor extent over the extracellular contrast agent. (orig.)

  3. Dose-dependent effects of cisplatin on the severity of testicular injury in Sprague Dawley rats: reactive oxygen species and endoplasmic reticulum stress

    Directory of Open Access Journals (Sweden)

    Soni KK

    2016-12-01

    Full Text Available Kiran Kumar Soni,1 Hye Kyung Kim,2 Bo Ram Choi,1 Keshab Kumar Karna,1 Jae Hyung You,1 Jai Seong Cha,1 Yu Seob Shin,1 Sung Won Lee,3 Chul Young Kim,4 Jong Kwan Park1 1Department of Urology, Institute for Medical Sciences, Chonbuk National University Medical School – Biomedical Research and Institute and Clinical Trial Center for Medical Devices, Chonbuk National University Hospital, Jeonju, 2College of Pharmacy, Kyungsung University, Busan, 3Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University Medical School, Seoul, 4College of Pharmacy, Hanyang University, Ansan, Republic of Korea Abstract: Cisplatin (CIS is used in the treatment of cancer, but its nonspecific systemic actions lead to toxic effects on other parts of the body. This study investigated the severity of CIS toxicity by increasing its dose over a constant time period. Sprague Dawley rats were divided into five treatment groups and control group with CIS (2, 4, 6, 8, and 10 mg/kg administered intraperitoneally for 5 days. The body and organs were weighed, epididymal sperm was counted, and sperm motility and sperm apoptosis were evaluated. Blood samples were evaluated for complete blood count, reactive oxygen and nitrogen species, malondialdehyde levels, and total testosterone. The testicular tissue was examined for steroidogenic acute regulatory protein and endoplasmic reticulum stress protein. Epididymal sperm was collected for CatSper Western blot. The toxic effects of different doses of CIS on the testis and kidney were compared histologically. The weights of body, testis, epididymis, prostate, seminal vesicle, and kidney; sperm count; sperm motility; steroidogenic acute regulatory protein level; and epididymal sperm count were significantly lower in the CIS-treated groups than in the control group. In contrast, sperm apoptosis, plasma reactive oxygen and nitrogen species, and malondialdehyde, testosterone, red blood cell

  4. Novel route synthesis of porous and solid gold nanoparticles for investigating their comparative performance as contrast agent in computed tomography scan and effect on liver and kidney function

    Directory of Open Access Journals (Sweden)

    Aziz F

    2017-02-01

    Full Text Available Farooq Aziz,1,2 Ayesha Ihsan,1 Aalia Nazir,2 Ishaq Ahmad,3 Sadia Zafar Bajwa,1 Asma Rehman,1 Abdoulaye Diallo,4 Waheed S Khan1 1Nanobiotechnology Group, National Institute for Biotechnology and Genetic Engineering (NIBGE, Faisalabad, 2Department of Physics, Islamia University of Bahawalpur, Bahawalpur, 3National Center for Physics, Quaid-I-Azam University, Islamabad, Pakistan; 4Laboratory of Photonics and Nano-Fabrication, Faculty of Science and Technology, Cheikh Anta Diop University of Dakar (UCAD, Dakar-Fann Dakar, Senegal Abstract: Gold nanoparticles (GNPs with dimension in the range of 1–100 nm have a prominent role in a number of biomedical applications like imaging, drug delivery, and cancer therapy owing to their unique optical features and biocompatibility. In this work, we report a novel technique for the synthesis of two types of GNPs namely porous gold nanoparticles (PGNPs and solid gold nanoparticles (SGNPs. PGNPs of size 35 nm were fabricated by reduction of gold (III solution with lecithin followed by addition of L-ascorbic acid and tri-sodium citrate, whereas SGNPs with a dimension of 28 nm were prepared by reflux method using lecithin as a single reducing agent. Comparative studies using PGNPs (λmax 560 nm and SGNPs (λmax 548 nm were conducted for evaluating their use as a contrast agent. These studies reveled that in direct computed tomography scan, PGNPs exhibited brighter contrast (45 HU than SGNPs (26 HU. To investigate the effect of PGNPs and SGNPs on the liver and kidney profile, male rabbits were intravenously injected with an equal dose of 1 mg/kg weight of PGNPs and SGNPs. The effect on biochemical parameters was evaluated 72 hours after intravenous (IV injection including liver function profile, renal (kidney function biomarker, random blood glucose value, and cholesterol level. During one comparison of contrast in CT scan, PGNPs showed significantly enhanced contrast in whole-rabbit and organ CT scan as

  5. Prevalence of latent and manifest hyperthyroidism in an iodine-deficient area: non-selected patient population admitted for CT studies with iodine-containing contrast agents

    International Nuclear Information System (INIS)

    Saam, T.; Hess, T.; Kasperk, C.; Kauffmann, G.W.; Duex, M.

    2005-01-01

    Purpose: to evaluate the prevalence of latent and manifest hyperthyroidism in a non-selected group of patients admitted for contrast enhanced CT studies blood samples were tested for the levels of thyroid-stimulating hormone (TSH). Material and methods: TSH blood levels were obtained in 548 consecutive patients who were scheduled for contrast-enhanced (Iopromide; 300 mg iodine/ml) CT scanning. In case of TSH levels registered (sodium perchlorate) was commenced before scanning. In case of TSH levels < 0.1 mU/l, CT scanning was not performed but further evaluation of the thyroid function was initiated. Results: TSH blood levels ranged from 0.4 to 7.5 mU/l in 512 patients, and 36 patients (6.6%) had TSH blood levels < 0.4 mU/l and 9 patients blood levels < 0.1 mU/l, with 32 of those patients (5.8%) having regular T3 and T4 blood levels consistent with latent hyperthyroidism. In 4 patients (0.8%), T3 or T4 blood levels were increased consistent with manifest hyperthyroidism. Conclusion: in South Germany, the prevalence of latent or manifest hyperthyroidism in a non-selected patient group is high. Therefore TSH blood levels should be obtained prior to contrast-enhanced CT studies. (orig.)

  6. Human whole-blood (1)H2O longitudinal relaxation with normal and high-relaxivity contrast reagents: influence of trans-cell-membrane water exchange.

    Science.gov (United States)

    Wilson, Gregory J; Woods, Mark; Springer, Charles S; Bastawrous, Sarah; Bhargava, Puneet; Maki, Jeffrey H

    2014-12-01

    Accurate characterization of contrast reagent (CR) longitudinal relaxivity in whole blood is required to predict arterial signal intensity in contrast-enhanced MR angiography (CE-MRA). This study measured the longitudinal relaxation rate constants (R1 ) over a concentration range for non-protein-binding and protein-binding CRs in ex vivo whole blood and plasma at 1.5 and 3.0 Tesla (T) under physiologic arterial conditions. Relaxivities of gadoteridol, gadobutrol, gadobenate, and gadofosveset were measured for [CR] from 0 to 18 mM [mmol(CR)/L(blood)]: the latter being the upper limit of what may be expected in CE-MRA. In plasma, the (1) H2 O R1 [CR]-dependence was nonlinear for gadobenate and gadofosveset secondary to CR interactions with the serum macromolecule albumin, and was well described by an analytical expression for effective 1:1 binding stoichiometry. In whole blood, the (1) H2 O R1 [CR]-dependence was markedly non-linear for all CRs, and was well-predicted by an expression for equilibrium exchange of water molecules between plasma and intracellular spaces using a priori parameter values only. In whole blood, (1) H2 O R1 exhibits a nonlinear relationship with [CR] over 0 to 18 mM CR. The nonlinearity is well described by exchange of water between erythrocyte and plasma compartments, and is particularly evident for high relaxivity CRs. © 2013 Wiley Periodicals, Inc.

  7. Mapping oxygen concentration in the awake mouse brain

    Science.gov (United States)

    Lyons, Declan G; Parpaleix, Alexandre; Roche, Morgane; Charpak, Serge

    2016-01-01

    Although critical for brain function, the physiological values of cerebral oxygen concentration have remained elusive because high-resolution measurements have only been performed during anesthesia, which affects two major parameters modulating tissue oxygenation: neuronal activity and blood flow. Using measurements of capillary erythrocyte-associated transients, fluctuations of oxygen partial pressure (Po2) associated with individual erythrocytes, to infer Po2 in the nearby neuropil, we report the first non-invasive micron-scale mapping of cerebral Po2 in awake, resting mice. Interstitial Po2 has similar values in the olfactory bulb glomerular layer and the somatosensory cortex, whereas there are large capillary hematocrit and erythrocyte flux differences. Awake tissue Po2 is about half that under isoflurane anesthesia, and within the cortex, vascular and interstitial Po2 values display layer-specific differences which dramatically contrast with those recorded under anesthesia. Our findings emphasize the importance of measuring energy parameters non-invasively in physiological conditions to precisely quantify and model brain metabolism. DOI: http://dx.doi.org/10.7554/eLife.12024.001 PMID:26836304

  8. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...

  9. Reduced cerebral blood flow and oxygen metabolism in extremely preterm neonates with low-grade germinal matrix- intraventricular hemorrhage

    Science.gov (United States)

    Lin, Pei-Yi; Hagan, Katherine; Fenoglio, Angela; Grant, P. Ellen; Franceschini, Maria Angela

    2016-05-01

    Low-grade germinal matrix-intraventricular hemorrhage (GM-IVH) is the most common complication in extremely premature neonates. The occurrence of GM-IVH is highly associated with hemodynamic instability in the premature brain, yet the long-term impact of low-grade GM-IVH on cerebral blood flow and neuronal health have not been fully investigated. We used an innovative combination of frequency-domain near infrared spectroscopy and diffuse correlation spectroscopy (FDNIRS-DCS) to measure cerebral oxygen saturation (SO2) and an index of cerebral blood flow (CBFi) at the infant’s bedside and compute an index of cerebral oxygen metabolism (CMRO2i). We enrolled twenty extremely low gestational age (ELGA) neonates (seven with low-grade GM-IVH) and monitored them weekly until they reached full-term equivalent age. During their hospital stay, we observed consistently lower CBFi and CMRO2i in ELGA neonates with low-grade GM-IVH compared to neonates without hemorrhages. Furthermore, lower CBFi and CMRO2i in the former group persists even after the resolution of the hemorrhage. In contrast, SO2 does not differ between groups. Thus, CBFi and CMRO2i may have better sensitivity than SO2 in detecting GM-IVH-related effects on infant brain development. FDNIRS-DCS methods may have clinical benefit for monitoring the evolution of GM-IVH, evaluating treatment response, and potentially predicting neurodevelopmental outcome.

  10. Benzene metabolite levels in blood and bone marrow of B6C3F{sub 1} mice after low-level exposure

    Energy Technology Data Exchange (ETDEWEB)

    Bechtold, W.E.; Strunk, M.R.; Thornton-Manning, J.R. [and others

    1995-12-01

    Studies at the Inhalation Toxicology Research Institute (ITRI) have explored the species-specific uptake and metabolism of benzene. Results have shown that metabolism is dependent on both dose and route of administration. Of particular interest were shifts in the major metabolic pathways as a function of exposure concentration. In these studies, B6C3F{sub 1} mice were exposed to increasing levels of benzene by either gavage or inhalation. As benzene internal dose increased, the relative amounts of muconic acid and hydroquinone decreased. In contrast, the relative amount of catechol increased with increasing exposure. These results show that the relative levels of toxic metabolites are a function of exposure level. Based on these results and assuming a linear relationship between exposure concentration and levels of bone marrow metabolites, it would be difficult to detect an elevation of any phenolic metabolites above background after occupational exposures to the OSHA Permissible Exposure Limit of 1 ppm benzene.

  11. Local cerebral blood flow (1CBF) and oxygen consumption (1CMRO2) in evolving irreversible ischemic infarction: a study with positron tomography and oxygen-15

    International Nuclear Information System (INIS)

    Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Comar, D.; Bousser, M.G.; Bories, J.; Castaigne, P.; Cabanis, E.

    1982-09-01

    In 25 patients suffering from cerebral ischemia set up in the area of the internal carotid artery the local cerebral blood flow (lCBF) and local cerebral oxygen consumption (lCMRO 2 ) were measured by the method of continuous inhalation of oxygen 15-labelled gas combined with positron emission tomography. These two local parameters and their ratio, the local oxygen extraction rate (lO 2 E), were studied inside the brain region tending spontaneously towards ischemic necrosis, a zone defined by means of repeated tomodensitometric examinations. The essential facts observed are the variability of the lCBF and the lO 2 E values, from extremely low to extremely high, whereas the collapse of the lCMRO 2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO 2 decrease to a level below about 70% of the controlateral value indicating that the necrosis is spontaneously irreparable. These results are discussed in the light of published data

  12. Control of oxygen tension recapitulates zone-specific functions in human liver microphysiology systems.

    Science.gov (United States)

    Lee-Montiel, Felipe T; George, Subin M; Gough, Albert H; Sharma, Anup D; Wu, Juanfang; DeBiasio, Richard; Vernetti, Lawrence A; Taylor, D Lansing

    2017-10-01

    developed and present a method for computationally modeling and measuring oxygen that can easily be implemented in all MPS models. We have applied this method in a liver MPS in which we are then able to control oxygenation in separate devices and demonstrate that zonation-dependent hepatocyte functions in the MPS recapitulate what is known about in vivo liver physiology. We believe that this advance allows a deep experimental investigation on the role of zonation in liver metabolism and disease. In addition, modeling and measuring oxygen tension will be required as investigators migrate from PDMS to plastic and glass devices.

  13. Caffeine reduces resting-state BOLD functional connectivity in the motor cortex.

    Science.gov (United States)

    Rack-Gomer, Anna Leigh; Liau, Joy; Liu, Thomas T

    2009-05-15

    In resting-state functional magnetic resonance imaging (fMRI), correlations between spontaneous low-frequency fluctuations in the blood oxygenation level dependent (BOLD) signal are used to assess functional connectivity between different brain regions. Changes in resting-state BOLD connectivity measures are typically interpreted as changes in coherent neural activity across spatially distinct brain regions. However, this interpretation can be complicated by the complex dependence of the BOLD signal on both neural and vascular factors. For example, prior studies have shown that vasoactive agents that alter baseline cerebral blood flow, such as caffeine and carbon dioxide, can significantly alter the amplitude and dynamics of the task-related BOLD response. In this study, we examined the effect of caffeine (200 mg dose) on resting-state BOLD connectivity in the motor cortex across a sample of healthy young subjects (N=9). We found that caffeine significantly (pcaffeine. These results suggest that caffeine usage should be carefully considered in the design and interpretation of resting-state BOLD fMRI studies.

  14. Atherosclerotic renal artery stenosis is associated with elevated cell cycle arrest markers related to reduced renal blood flow and postcontrast hypoxia.

    Science.gov (United States)

    Saad, Ahmed; Wang, Wei; Herrmann, Sandra M S; Glockner, James F; Mckusick, Michael A; Misra, Sanjay; Bjarnason, Haraldur; Lerman, Lilach O; Textor, Stephen C

    2016-11-01

    Atherosclerotic renal artery stenosis (ARAS) reduces renal blood flow (RBF), ultimately leading to kidney hypoxia and inflammation. Insulin-like growth factor binding protein-7 (IGFBP-7) and tissue inhibitor of metalloproteinases-2 (TIMP-2) are biomarkers of cell cycle arrest, often increased in ischemic conditions and predictive of acute kidney injury (AKI). This study sought to examine the relationships between renal vein levels of IGFBP-7, TIMP-2, reductions in RBF and postcontrast hypoxia as measured by blood oxygen level-dependent (BOLD) magnetic resonance imaging. Renal vein levels of IGFBP-7 and TIMP-2 were obtained in an ARAS cohort (n= 29) scheduled for renal artery stenting and essential hypertensive (EH) healthy controls (n = 32). Cortical and medullary RBFs were measured by multidetector computed tomography (CT) immediately before renal artery stenting and 3 months later. BOLD imaging was performed before and 3 months after stenting in all patients, and a subgroup (N = 12) underwent repeat BOLD imaging 24 h after CT/stenting to examine postcontrast/procedure levels of hypoxia. Preintervention IGFBP-7 and TIMP-2 levels were elevated in ARAS compared with EH (18.5 ± 2.0 versus 15.7 ± 1.5 and 97.4 ± 23.1 versus 62.7 ± 9.2 ng/mL, respectively; Pblood flow (r = -0.59, P= 0.004). These data demonstrate elevated IGFBP-7 and TIMP-2 levels in ARAS as a function of the degree of reduced RBF. Elevated baseline IGFBP-7 levels were associated with protection against postimaging hypoxia, consistent with 'ischemic preconditioning'. Despite contrast injection and stenting, AKI in these high-risk ARAS subjects with elevated IGFBP-7/TIMP-2 was rare and did not affect long-term kidney function. © The Author 2016. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

  15. Effect of oxygen levels on the physiology of dendritic cells: implications for adoptive cell therapy.

    Science.gov (United States)

    Futalan, Diahnn; Huang, Chien-Tze; Schmidt-Wolf, Ingo G H; Larsson, Marie; Messmer, Davorka

    2011-01-01

    Dendritic cell (DC)-based adoptive tumor immunotherapy approaches have shown promising results, but the incidence of tumor regression is low and there is an evident call for identifying culture conditions that produce DCs with a more potent Th1 potential. Routinely, DCs are differentiated in CO(2) incubators under atmospheric oxygen conditions (21% O(2)), which differ from physiological oxygen levels of only 3-5% in tissue, where most DCs reside. We investigated whether differentiation and maturation of DCs under physiological oxygen levels could produce more potent T-cell stimulatory DCs for use in adoptive immunotherapy. We found that immature DCs differentiated under physiological oxygen levels showed a small but significant reduction in their endocytic capacity. The different oxygen levels did not influence their stimuli-induced upregulation of cluster of differentiation 54 (CD54), CD40, CD83, CD86, C-C chemokine receptor type 7 (CCR7), C-X-C chemokine receptor type 4 (CXCR4) and human leukocyte antigen (HLA)-DR or the secretion of interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-10 in response to lipopolysaccharide (LPS) or a cytokine cocktail. However, DCs differentiated under physiological oxygen level secreted higher levels of IL-12(p70) after exposure to LPS or CD40 ligand. Immature DCs differentiated at physiological oxygen levels caused increased T-cell proliferation, but no differences were observed for mature DCs with regard to T-cell activation. In conclusion, we show that although DCs generated under atmospheric or physiological oxygen conditions are mostly similar in function and phenotype, DCs differentiated under physiological oxygen secrete larger amounts of IL-12(p70). This result could have implications for the use of ex vivo-generated DCs for clinical studies, since DCs differentiated at physiological oxygen could induce increased Th1 responses in vivo.

  16. Oxygen-dependent sensitization of irradiated cells

    International Nuclear Information System (INIS)

    Ewing, D.; Powers, E.L.

    1979-01-01

    Attention is focused primarily on O 2 effects in three biological systems, all tested in suspension: bacterial spores, vegetative bacterial cells, and mammalian cells. Information from these systems shows that O 2 has more than one process through which it can act. Studies with bacterial spore suspensions provide clear evidence that multiple components to oxygen-dependent radiation sensitization exist. Studies with mammalian cell suspensions also show that at least two oxygen-dependent sensitization processes can be distinguished. Similar studies with vegetative bacteria in suspension have not resolved oxic sensitization into components. The roles of water-derived radicals in radiation sensitivity and, specifically, in sensitization by O 2 were examined. OH radicals are clearly implicated in damage in all three biological test systems. However, the specific roles proposed for OH radicals are different in these organisms. In bacterial spores, OH radical removal in itself does not protect in anoxia or in high concentrations of O 2 . OH radical removal over a limited intermediate range of O 2 concentrations will, however, protect. OH radical scavenging probably results in the formation of the actual protector. In bacteria, the supposition is that OH radical removal will protect both in anoxia and in the presence of O 2 . OH radicals probably react with a cellular target molecule and leave a radicalsite; this is the site which can then react with O 2 to cause damage; DNA is the likely cellular target. In mammalian cells, a reaction scheme, similar to that proposed for bacteria, has been suggested for O 2 -dependent sensitization

  17. Regional myocardial oxygen consumption estimated by carbon-11 acetate and positron emission tomography before and after repetitive ischemia

    DEFF Research Database (Denmark)

    Kofoed, K F; Hansen, P R; Holm, S

    2000-01-01

    alternating with 5 minutes of reperfusion. Before and after repetitive coronary occlusions, oxygen 15 water/oxygen 15 carbon monoxide (blood flow), and 11C-acetate (oxygen consumption) PET imaging were performed. Left ventricular regional systolic wall thickening was measured with sonomicrometry. Forty......BACKGROUND: Preserved myocardial oxygen consumption estimated by carbon 11-acetate and positron emission tomography (PET) in myocardial regions with chronic but reversibly depressed contractile function in patients with ischemic heart disease have been suggested to be caused by repeated short......-five minutes after the ischemic episodes, systolic ventricular wall thickening was decreased by 90%, whereas myocardial blood flow was reduced by 21% compared with baseline values (P consumption was unaltered compared with the baseline level...

  18. Blood Glucose Levels and Problem Behavior

    Science.gov (United States)

    Valdovinos, Maria G.; Weyand, David

    2006-01-01

    The relationship between varying blood glucose levels and problem behavior during daily scheduled activities was examined. The effects that varying blood glucose levels had on problem behavior during daily scheduled activities were examined. Prior research has shown that differing blood glucose levels can affect behavior and mood. Results of this…

  19. Fluorescence spectra of blood plasma treated with ultraviolet irradiation in vivo

    Science.gov (United States)

    Zalesskaya, G. A.; Maslova, T. O.

    2010-09-01

    We have studied the fluorescence spectra of blood plasma from patients with acute coronary syndrome, and also the effect of therapeutic doses of in vivo ultraviolet blood irradiation (UBI) on the spectra. We have established that the maxima in the fluorescence spectra of the original plasma samples, obtained from unirradiated blood, are located in the wavelength interval 330-340 nm, characteristic for the fluorescence of tryptophan residues. In extracorporeal UBI ( λ = 254 nm), we observed changes in the shape and also both a blue and a red shift in the maxima of the fluorescence spectra, differing in magnitude for blood plasma samples from different patients in the test group. We show that UBI-initiated changes in the fluorescence spectra of the plasma depend on the original pathological disturbances of metabolite levels, and also on the change in the oxygen-transport function of the blood and the acid-base balance, affecting the oxidative stability of the plasma. We have concluded that UV irradiation, activating buffer systems in the blood, has an effect on the universal and specific interactions of the tryptophan residue with the amino acid residues and water surrounding it.

  20. A novel Bayesian approach to accounting for uncertainty in fMRI-derived estimates of cerebral oxygen metabolism fluctuations.

    Science.gov (United States)

    Simon, Aaron B; Dubowitz, David J; Blockley, Nicholas P; Buxton, Richard B

    2016-04-01

    Calibrated blood oxygenation level dependent (BOLD) imaging is a multimodal functional MRI technique designed to estimate changes in cerebral oxygen metabolism from measured changes in cerebral blood flow and the BOLD signal. This technique addresses fundamental ambiguities associated with quantitative BOLD signal analysis; however, its dependence on biophysical modeling creates uncertainty in the resulting oxygen metabolism estimates. In this work, we developed a Bayesian approach to estimating the oxygen metabolism response to a neural stimulus and used it to examine the uncertainty that arises in calibrated BOLD estimation due to the presence of unmeasured model parameters. We applied our approach to estimate the CMRO2 response to a visual task using the traditional hypercapnia calibration experiment as well as to estimate the metabolic response to both a visual task and hypercapnia using the measurement of baseline apparent R2' as a calibration technique. Further, in order to examine the effects of cerebral spinal fluid (CSF) signal contamination on the measurement of apparent R2', we examined the effects of measuring this parameter with and without CSF-nulling. We found that the two calibration techniques provided consistent estimates of the metabolic response on average, with a median R2'-based estimate of the metabolic response to CO2 of 1.4%, and R2'- and hypercapnia-calibrated estimates of the visual response of 27% and 24%, respectively. However, these estimates were sensitive to different sources of estimation uncertainty. The R2'-calibrated estimate was highly sensitive to CSF contamination and to uncertainty in unmeasured model parameters describing flow-volume coupling, capillary bed characteristics, and the iso-susceptibility saturation of blood. The hypercapnia-calibrated estimate was relatively insensitive to these parameters but highly sensitive to the assumed metabolic response to CO2. Copyright © 2016 Elsevier Inc. All rights reserved.