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Sample records for tissue oxygenation monitoring

  1. Retrievable micro-inserts containing oxygen sensors for monitoring tissue oxygenation using EPR oximetry

    International Nuclear Information System (INIS)

    Dinguizli, M; Beghein, N; Gallez, B

    2008-01-01

    Tissue oxygenation is a crucial parameter in various physiopathological situations and can influence the therapeutic response of tumours. EPR oximetry is a reliable method for assessing and monitoring oxygen levels in vivo over long periods of time. Among the different paramagnetic oxygen sensors available for EPR oximetry, lithium phthalocyanine (LiPc) is a serious candidate for in vivo applications because of its narrow linewidth and its high signal-to-noise ratio. To enhance the biocompatibility of the sensors, fluoropolymer Teflon AF2400 was used to make cylindrical micro-inserts containing LiPc crystals. This new micro-pellet design has several advantages for in vivo studies, including the possibility of being able to choose the implant size, a high sensor content, the facility of in vivo insertion and complete protection with preservation of the oxygen sensor's characteristics. The response to oxygen and the kinetics of this response were tested using in vivo EPR: no differences were observed between micro-inserts and uncoated LiPc crystals. Pellets implanted in vivo in muscles conserved their responsiveness over a long period of time (∼two months), which is much longer than the few days of stability observed using LiPc crystals without protection by the implant. Finally, evaluation of the biocompatibility of the implants revealed no inflammatory reaction around the implantation area

  2. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    Science.gov (United States)

    2008-04-01

    28. Alagoz, T., R. Buller, B. Anderson, K. Terrell , R...and oxygenation Ann . New Acad. Sci. 838 29–45 Chapman J D, Stobbe C C, Arnfield M R, Santus R, Lee J and McPhee M S 1991 Oxygen dependency of tumor

  3. Direct tissue oxygen monitoring by in vivo photoacoustic lifetime imaging (PALI)

    Science.gov (United States)

    Shao, Qi; Morgounova, Ekaterina; Ashkenazi, Shai

    2014-03-01

    Tissue oxygen plays a critical role in maintaining tissue viability and in various diseases, including response to therapy. Images of oxygen distribution provide the history of tissue hypoxia and evidence of oxygen availability in the circulatory system. Currently available methods of direct measuring or imaging tissue oxygen all have significant limitations. Previously, we have reported a non-invasive in vivo imaging modality based on photoacoustic lifetime. The technique maps the excited triplet state of oxygen-sensitive dye, thus reflects the spatial and temporal distribution of tissue oxygen. We have applied PALI on tumor hypoxia in small animals, and the hypoxic region imaged by PALI is consistent with the site of the tumor imaged by ultrasound. Here, we present two studies of applying PALI to monitor changes of tissue oxygen by modulations. The first study involves an acute ischemia model using a thin thread tied around the hind limb of a normal mouse to reduce the blood flow. PALI images were acquired before, during, and after the restriction. The drop of muscle pO2 and recovery from hypoxia due to reperfusion were observed by PALI tracking the same region. The second study modulates tissue oxygen by controlling the percentage of oxygen the mouse inhales. We demonstrate that PALI is able to reflect the change of oxygen level with respect to both hyperbaric and hypobaric conditions. We expect this technique to be very attractive for a range of clinical applications in which tissue oxygen mapping would improve therapy decision making and treatment planning.

  4. Simultaneous Monitoring of Vascular Oxygenation and Tissue Oxygen Tension of Breast Tumors Under Hyperbaric Oxygen Exposure

    National Research Council Canada - National Science Library

    Xia, Mengna

    2005-01-01

    The goals of the study in the first stage are 1) to develop a mathematic model by which we can derive tumor blood flow and metabolic rate of oxygen from hemoglobin concentration during interventions, 2...

  5. Brain Tissue Oxygen: In Vivo Monitoring with Carbon Paste Electrodes

    Directory of Open Access Journals (Sweden)

    John P. Lowry

    2005-11-01

    Full Text Available In this communication we review selected experiments involving the use ofcarbon paste electrodes (CPEs to monitor and measure brain tissue O2 levels in awakefreely-moving animals. Simultaneous measurements of rCBF were performed using the H2clearance technique. Voltammetric techniques used include both differential pulse (O2 andconstant potential amperometry (rCBF. Mild hypoxia and hyperoxia produced rapidchanges (decrease and increase respectively in the in vivo O2 signal. Neuronal activation(tail pinch and stimulated grooming produced similar increases in both O2 and rCBFindicating that CPE O2 currents provide an index of increases in rCBF when such increasesexceed O2 utilization. Saline injection produced a transient increase in the O2 signal whilechloral hydrate produced slower more long-lasting changes that accompanied the behavioralchanges associated with anaesthesia. Acetazolamide increased O2 levels through an increasein rCBF.

  6. The MOST - Monitor for Oxygenation of Surface and Tissue.

    Science.gov (United States)

    1995-10-01

    anesthesia Effectiveness of COR Bio-feedback for peripheral vasodilation Relationship of CPAP and PEEP to atelectasis Waveforms Diagnosis of irregularities...deliberate hypoxia in premature infants Servo-controlled saturation, prematures Converse 02 in home 02 therapy Determine optimal PEEP and CPAP Monitor...Kusakawa I, Ohata J, Kawano T, Honma Y. Use of Pulse Oximetry In Neonatal Anesthe- sia. J Perinatology. 1987:7;343-5. Nishimura S, Tomita Y, Horiuchi T

  7. Near infrared spectroscopy (NIRS) to monitor tissue haemoglobin (and myoglobin) oxygenation

    NARCIS (Netherlands)

    Scheeren, T. W. L.

    2010-01-01

    Introduction: Tissue oxygenation may be monitored noninvasively by near infrared spectroscopy (NIRS) both on the thenar eminescence (muscle) and on the forehead (brain). Thenar measurement have been used to guide therapy in trauma patients ( 1 ) and to determine the prognosis of septic patients ( 2

  8. Design of a tissue oxygenation monitor and verification on human skin

    Science.gov (United States)

    Liu, Hongyuan; Kohl-Bareis, Matthias; Huang, Xiabing

    2011-07-01

    We report the design of a tissue oxygen and temperature monitor. The non-invasive, fibre based device monitors tissue haemoglobin (Hb) and oxygen saturation (SO2) and is based on white-light reflectance spectroscopy.Visible light with wavelengths in the 500 - 650nm range is utilized. The spectroscopic algorithm takes into account the tissue scattering and melanin absorption for the calculation of tissue haemoglobin concentration and oxygen saturation. The monitor can probe superficial layers of tissue with a high spatial resolution (mm3) and a high temporal resolution (40 Hz). It provides an accurate measurement with the accuracy of SO2 at 2 % and high reliability with less than 2 % variation of continuous SO2 measurement over 12 hours. It can also form a modular system when used in conjunction with a laser Doppler monitor, enabling simultaneous measurements of Hb, SO2 and blood flow. We found experimentally that the influence of the source-detector separation on the haemoglobin parameters is small. This finding is discussed by Monte Carlo simulations for the depth sensitivity profile. The influence of probe pressure and the skin pigmentation on the measurement parameters are assessed before in vivo experimental data is presented. The combination with laser Doppler flowmetry demonstrates the importance of a measurement of both the haemoglobin and the blood flow parameters for a full description of blood tissue perfusion. This is discussed in experimental data on human skin during cuff occlusion and after hyperemisation by a pharmacological cream. Strong correlation is observed between tissue oxygen (Hb and SO2) and blood flow measurements.

  9. Concurrent Longitudinal EPR Monitoring of Tissue Oxygenation, Acidosis, and Reducing Capacity in Mouse Xenograft Tumor Models.

    Science.gov (United States)

    Bobko, Andrey A; Evans, Jason; Denko, Nicholas C; Khramtsov, Valery V

    2017-06-01

    Tissue oxygenation, extracellular acidity, and tissue reducing capacity are among crucial parameters of tumor microenvironment (TME) of significant importance for tumor pathophysiology. In this paper, we demonstrate the complementary application of particulate lithium octa-n-butoxy-naphthalocyanine and soluble nitroxide paramagnetic probes for monitoring of these TME parameters using electron paramagnetic resonance (EPR) technique. Two different types of therapeutic interventions were studied: hypothermia and systemic administration of metabolically active drug. In summary, the results demonstrate the utility of EPR technique for non-invasive concurrent longitudinal monitoring of physiologically relevant chemical parameters of TME in mouse xenograft tumor models, including that under therapeutic intervention.

  10. Non-invasive monitoring of tissue oxygenation during laparoscopic donor nephrectomy

    Directory of Open Access Journals (Sweden)

    Kirk Allan D

    2008-04-01

    Full Text Available Abstract Background Standard methods for assessment of organ viability during surgery are typically limited to visual cues and tactile feedback in open surgery. However, during laparoscopic surgery, these processes are impaired. This is of particular relevance during laparoscopic renal donation, where the condition of the kidney must be optimized despite considerable manipulation. However, there is no in vivo methodology to monitor renal parenchymal oxygenation during laparoscopic surgery. Methods We have developed a method for the real time, in vivo, whole organ assessment of tissue oxygenation during laparoscopic nephrectomy to convey meaningful biological data to the surgeon during laparoscopic surgery. We apply the 3-CCD (charge coupled device camera to monitor qualitatively renal parenchymal oxygenation with potential real-time video capability. Results We have validated this methodology in a porcine model across a range of hypoxic conditions, and have then applied the method during clinical laparoscopic donor nephrectomies during clinically relevant pneumoperitoneum. 3-CCD image enhancement produces mean region of interest (ROI intensity values that can be directly correlated with blood oxygen saturation measurements (R2 > 0.96. The calculated mean ROI intensity values obtained at the beginning of the laparoscopic nephrectomy do not differ significantly from mean ROI intensity values calculated immediately before kidney removal (p > 0.05. Conclusion Here, using the 3-CCD camera, we qualitatively monitor tissue oxygenation. This means of assessing intraoperative tissue oxygenation may be a useful method to avoid unintended ischemic injury during laparoscopic surgery. Preliminary results indicate that no significant changes in renal oxygenation occur as a result of pneumoperitoneum.

  11. Evaluation of tissue oxygen measurements for flap monitoring in an animal model

    DEFF Research Database (Denmark)

    Bonde, Christian; Elberg, Jens; Holstein-Rathlou, N.-H.

    2008-01-01

    Tissue oxygen tension (p(ti)O(2)) measurements are common in neurosurgery but uncommon in plastic surgery. We examined this technique as a monitoring method with probe placement in the subcutaneous tissue and addressed the importance of probe placement. Myocutaneous flaps were raised in an animal...... model and p(ti)O(2) measurements performed at different levels in the subcutaneous fat. Flap artery and vein were occluded until a 50% p(ti)O(2) reduction had occurred (T(1/2)). We found no significant effect of depth (P>0.10) on the level of p(ti)O(2). T(1/2)(arterial) was 7.2 minutes and T(1/2)(venous......) was 18 minutes. We found no significant relation between initial levels of p(ti)O(2) and T(1/2). Location of the probe and absolute p(ti)O(2) value is of little relevance for flap monitoring. It is the relative change in p(ti)O(2) that is important. The p(ti)O(2) technique is well suited for monitoring...

  12. Monitoring tissue oxygen availability with near infrared spectroscopy (NIRS) in health and disease

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Olesen, J

    2001-01-01

    , brain and connective tissue, and more recently it has been used in the clinical setting to assess circulatory and metabolic abnormalities. Quantitative measures of blood flow are also possible using NIRS and a light-absorbing tracer, which can be applied to evaluate circulatory responses to exercise......Near infrared spectroscopy (NIRS) is becoming a widely used research instrument to measure tissue oxygen (O2) status non-invasively. Continuous-wave spectrometers are the most commonly used devices, which provide semi-quantitative changes in oxygenated and deoxygenated hemoglobin in small blood...... vessels (arterioles, capillaries and venules). Refinement of NIRS hardware and the algorithms used to deconvolute the light absorption signal have improved the resolution and validity of cytochrome oxidase measurements. NIRS has been applied to measure oxygenation in a variety of tissues including muscle...

  13. Cerebral oxygenation in contusioned vs. nonlesioned brain tissue: monitoring of PtiO2 with Licox and Paratrend.

    Science.gov (United States)

    Sarrafzadeh, A S; Kiening, K L; Bardt, T F; Schneider, G H; Unterberg, A W; Lanksch, W R

    1998-01-01

    Brain tissue PO2 in severely head injured patients was monitored in parallel with two different PO2-microsensors (Licox and Paratrend). Three different locations of sensor placement were chosen: (1) both catheters into non lesioned tissue (n = 3), (2) both catheters into contusioned tissue (n = 2), and (3) one catheter (Licox) into pericontusional versus one catheter (Paratrend) into non lesioned brain tissue (n = 2). Mean duration of PtiO2-monitoring with both microsensors in parallel was 68.1 hours. Brain tissue PO2 varied when measured in lesioned and nonlesioned tissue. In non lesioned tissue both catheters closely correlated (delta Licox/Paratrend: mean PtiO2 delta lesioned/non lesioned: mean PtiO2: 10.3 mm Hg). In contusioned brain tissue PtiO2 was always below the "hypoxic threshold" of 10 mm Hg, independent of the type of microsensor used. During a critical reduction in cerebral perfusion pressure (PO2, only increased PtiO2 when measured in pericontusional and nonlesioned brain. To recognize critical episodes of hypoxia or ischemia, PtiO2-monitoring of cerebral oxygenation is recommended in nonlesioned brain tissue.

  14. Biochemical changes related to hypoxia during cerebral aneurysm surgery: combined microdialysis and tissue oxygen monitoring: case report.

    Science.gov (United States)

    Hutchinson, P J; Al-Rawi, P G; O'Connell, M T; Gupta, A K; Pickard, J D; Kirkpatrick, P J

    2000-01-01

    The objective of this study was to monitor brain metabolism on-line during aneurysm surgery, by combining the use of a multiparameter (brain tissue oxygen, brain carbon dioxide, pH, and temperature) sensor with microdialysis (extracellular glucose, lactate, pyruvate, and glutamate). The case illustrates the potential value of these techniques by demonstrating the effects of adverse physiological events on brain metabolism and the ability to assist in both intraoperative and postoperative decision-making. A 41-year-old woman presented with a World Federation of Neurological Surgeons Grade I subarachnoid hemorrhage. Angiography revealed a basilar artery aneurysm that was not amenable to coiling, so the aneurysm was clipped. Before the craniotomy was performed, a multiparameter sensor and a microdialysis catheter were inserted to monitor brain metabolism. During the operation, the brain oxygen level decreased, in relation to biochemical changes, including the reduction of extracellular glucose and pyruvate and the elevation of lactate and glutamate. These changes were reversible. However, when the craniotomy was closed, a second decrease in brain oxygen occurred in association with brain swelling, which immediately prompted a postoperative computed tomographic scan. The scan demonstrated acute hydrocephalus, requiring external ventricular drainage. The patient made a full recovery. The monitoring techniques influenced clinical decision-making in the treatment of this patient. On-line measurement of brain tissue gases and extracellular chemistry has the potential to assist in the perioperative and postoperative management of patients undergoing complex cerebrovascular surgery and to establish the effects of intervention on brain homeostasis.

  15. Animal studies using an oxygen-tension sensor for tissue viability monitoring

    NARCIS (Netherlands)

    Tanase, D.; Komen, N.; Draaijer, A.; Lange, J.F.; Kleinrensink, G.J.; Jeekel, J.; French, P.J.

    2008-01-01

    Leakage at the site of an anastomosis is the main, yet unsolved reason for mortality in abdominal surgery. Every year, a large number of patients die due to anastomotic leakage after surgery. An objective aid to monitor the anastomotic site pre- and postoperatively and detect leakage at an early

  16. Journal of Clinical Monitoring and Computing 2015 end of year summary : tissue oxygenation and microcirculation

    NARCIS (Netherlands)

    Scheeren, T W L

    Last year we started this series of end of year summaries of papers published in the 2014 issues of the Journal Of Clinical Monitoring And Computing with a review on near infrared spectroscopy (Scheeren et al. in J Clin Monit Comput 29(2):217-220, 2015). This year we will broaden the scope and

  17. The limitations of tissue-oxygen measurement and positron emission tomography as additional methods for postoperative breast reconstruction free-flap monitoring.

    Science.gov (United States)

    Schrey, Aleksi; Niemi, Tarja; Kinnunen, Ilpo; Minn, Heikki; Vahlberg, Tero; Kalliokoski, Kari; Suominen, Erkki; Grénman, Reidar; Aitasalo, Kalle

    2010-02-01

    Twelve patients who underwent breast reconstruction with a microvascular flap were monitored postoperatively with continuous partial tissue oxygenation (p(ti)O(2)) measurement. The regional blood flow (BF) of the entire flap was evaluated with positron emission tomography (PET) using oxygen-15-labelled water on the first postoperative (POP) morning to achieve data of the perfusion of the entire flap. A re-exploration was carried out if the p(ti)O(2) value remained lower than 15 mmHg for over 30 min. The mean p(ti)O(2) value of the flaps was 52.9+/-5.5 mmHg, whereas the mean BF values were 3.3+/-1.0 ml per 100 g min(-1). One false-positive result was detected by p(ti)O(2) measurement, resulting in an unnecessary re-exploration. Another re-operation suggested by the low p(ti)O(2) results was avoided due to the normal BF results assessed with PET. Totally, three flaps were re-explored. This prospective study suggests that continuous tissue-oxygen measurement with a polarographic needle probe is reliable for monitoring free breast flaps from one part of the flap, but assessing perfusion of the entire flap requires more complex monitoring methods, for example, PET. Clinical examination by experienced personnel remains important in free-breast-flap monitoring. PET could be useful in assessing free-flap perfusion in selected high-risk patients as an alternative to a re-operation when clinical examination and evaluation by other means are unreliable or present controversial results. 2008 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  18. Monitoring in microvascular tissue transfer by measurement of oxygen partial pressure: four years experience with 125 microsurgical transplants.

    Science.gov (United States)

    Jonas, René; Schaal, Thomas; Krimmel, Michael; Gülicher, Dirk; Reinert, Siegmar; Hoffmann, Jürgen

    2013-06-01

    In a prospective study, the characteristics and benefit of an invasive measurement of oxygen partial pressure (pO(2)) with the aid of a polarographic sensor were investigated in 125 microsurgical reconstructions of the head and neck area over a period of 45 months. Measurements were performed over 96 h in eight different types of microsurgically revascularized flaps for extra- and intraoral reconstructions and were evaluated separately for each flap type. Of 125 reconstructions the system indicated malperfusion in 18 cases. Salvage surgery was performed in 17 cases due to venous thrombosis (6 cases), arterial thrombosis (3 cases), a combination of arterial and venous thrombosis (2 cases), rheological problems (3 cases), venous insufficiency by hematoma (2 cases) and kinking of vessels (1 case). In 10 cases salvage surgery was successful, 7 flaps were lost despite salvage surgery. In all these cases, the polarographic probe indicated the necessity of salvage surgery correctly. After 96 h no malperfusion was seen. Postoperatively, a common and characteristic development of the oxygen partial pressure in different types of flaps was seen. Initially, a clear increase of pO(2) could be measured. During 96 h, a slow decrease of pO(2) was observed. In conclusion polarographic measurement of pO(2) can be an excellent apparative supplement for the postoperative clinical control of microsurgically revascularized transplants. In buried flaps, this technique represents the only reliable method for transplant monitoring. Copyright © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  19. Implantable oxygen microelectrode suitable for medium-term investigations of post-surgical tissue hypoxia and changes in tumor tissue oxygenation produced by radiotherapy

    International Nuclear Information System (INIS)

    Burke, T.R.; Johnson, R.J.; Krishnamsetty, C.B.; Sako, K.; Karakousis, C.; Wojtas, F.

    1980-01-01

    Teflon-covered platinum oxygen probes were used to monitor tissue oxygen levels in post-surgical cancer patients and those treated with radiotherapy. Progressive wound healing was usually accompanied by a decrease in tissue pO2. Radiotherapy produced a slight increase in pO2 while hyperthermia effected a significant increase in the oxygen level during 100% oxygen breathing

  20. Differences in breast tissue oxygenation following radiotherapy

    International Nuclear Information System (INIS)

    Dornfeld, Ken; Gessert, Charles E.; Renier, Colleen M.; McNaney, David D.; Urias, Rodolfo E.; Knowles, Denise M.; Beauduy, Jean L.; Widell, Sherry L.; McDonald, Bonita L.

    2011-01-01

    Tissue perfusion and oxygenation changes following radiotherapy may result from and/or contribute to the toxicity of treatment. Breast tissue oxygenation levels were determined in the treated and non-treated breast 1 year after radiotherapy for breast conserving treatment. Transcutaneous oxygenation varied between subjects in both treated and non-treated breast. Subjects without diabetes mellitus (n = 16) had an average oxygenation level of 64.8 ± 19.9 mmHg in the irradiated breast and an average of 72.3 ± 18.1 mmHg (p = 0.018) at the corresponding location in the control breast. Patients with diabetes (n = 4) showed a different oxygenation pattern, with lower oxygenation levels in control tissue and no decrease in the irradiated breast. This study suggests oxygenation levels in normal tissues vary between patients and may respond differently after radiotherapy.

  1. Oxygen delivery in irradiated normal tissue

    Energy Technology Data Exchange (ETDEWEB)

    Kiani, M.F.; Ansari, R. [Univ. of Tennessee Health Science Center, Memphis, TN (United States). School of Biomedical Engineering; Gaber, M.W. [St. Jude Children' s Research Hospital, Memphis, TN (United States)

    2003-03-01

    Ionizing radiation exposure significantly alters the structure and function of microvascular networks, which regulate delivery of oxygen to tissue. In this study we use a hamster cremaster muscle model to study changes in microvascular network parameters and use a mathematical model to study the effects of these observed structural and microhemodynamic changes in microvascular networks on oxygen delivery to the tissue. Our experimental observations indicate that in microvascular networks while some parameters are significantly affected by irradiation (e.g. red blood cell (RBC) transit time), others remain at the control level (e.g. RBC path length) up to 180 days post-irradiation. The results from our mathematical model indicate that tissue oxygenation patterns are significantly different in irradiated normal tissue as compared to age-matched controls and the differences are apparent as early as 3 days post irradiation. However, oxygen delivery to irradiated tissue was not found to be significantly different from age matched controls at any time between 7 days to 6 months post-irradiation. These findings indicate that microvascular late effects in irradiated normal tissue may be due to factors other than compromised tissue oxygenation. (author)

  2. Oxygen diffusion and oxygen effect in tumor tissue

    International Nuclear Information System (INIS)

    Eissa, H.M.; Hehn, G.

    1979-06-01

    The diffusion of oxygen in tumor cords of bronchus carcinoma of the lung have been studied with refined computer methods for solving the diffusion equation in axis symmetric tumor structures. In this tumor configuration we may find three different regions consisting of euoxic cells, hypoxic tumor cells and necrotic parts. In the case of oxygen supply from a capillary inside a cylinder of tumor tissue with radius 200 μm or in a tumor cord of radius 300 μm with oxygen supply by capillaries outside, we get a relation of well oxygenated cells to hypoxic cells approximately as 1:8 or as 1:1.1 respectively. Of course most of the tumor cords observed in histological slices have smaller diameters, so that an average of approximately 20% hypoxic cells can be assumed. Based on the work of Ardenne, the diffusion of oxygen and glucose in a tumor of type DS-carcinosarcom has been investigated in both intact tumor and tumor treated with ionizing radiation. We can show that a strong reoxygenation effect takes place in that the well supplied regions may increase in some tumor configurations up to a factor of four by volume. The biological consequences of the oxygen pressure determined in tumor cells are discussed in detail. The investigation of oxygen diffusion in the intercapillary tumor region should give a quantitative physical basis for considering the oxygen effect with the aim to explain the advantages of neutron therapy against conventional radiotherapy. (orig./MG) [de

  3. Alarm points for fixed oxygen monitors

    International Nuclear Information System (INIS)

    Miller, G.C.

    1987-05-01

    Oxygen concentration monitors were installed in a vault where numerous pipes carried inert cryogens and gases to the Mirror Fusion Test Facility (MFTF-B) experimental vessel at Lawrence Livermore National Laboratory (LLNL). The problems associated with oxygen-monitoring systems and the reasons why such monitors were installed were reviewed. As a result of this review, the MFTF-B monitors were set to sound an evacuation alarm when the oxygen concentration fell below 18%. We chose the 18% alarm criterion to minimize false alarms and to allow time for personnel to escape in an oxygen-deficient environment

  4. Simultaneous sampling of tissue oxygenation and oxygen consumption in skeletal muscle.

    Science.gov (United States)

    Nugent, William H; Song, Bjorn K; Pittman, Roland N; Golub, Aleksander S

    2016-05-01

    Under physiologic conditions, microvascular oxygen delivery appears to be well matched to oxygen consumption in respiring tissues. We present a technique to measure interstitial oxygen tension (PISFO2) and oxygen consumption (VO2) under steady-state conditions, as well as during the transitions from rest to activity and back. Phosphorescence Quenching Microscopy (PQM) was employed with pneumatic compression cycling to achieve 1 to 10 Hz sampling rates of interstitial PO2 and simultaneous recurrent sampling of VO2 (3/min) in the exteriorized rat spinotrapezius muscle. The compression pressure was optimized to 120-130 mmHg without adverse effect on the tissue preparation. A cycle of 5s compression followed by 15s recovery yielded a resting VO2 of 0.98 ± 0.03 ml O2/100 cm(3)min while preserving microvascular oxygen delivery. The measurement system was then used to assess VO2 dependence on PISFO2 at rest and further tested under conditions of isometric muscle contraction to demonstrate a robust ability to monitor the on-kinetics of tissue respiration and the compensatory changes in PISFO2 during contraction and recovery. The temporal and spatial resolution of this approach is well suited to studies seeking to characterize microvascular oxygen supply and demand in thin tissues. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Metabolic Prosthesis for Oxygenation of Ischemic Tissue

    Energy Technology Data Exchange (ETDEWEB)

    Greenbaum, Elias [ORNL

    2009-01-01

    This communication discloses new ideas and preliminary results on the development of a "metabolic prosthesis" for local oxygenation of ischemic tissue under physiological neutral conditions. We report for the first time the selective electrolysis of physiological saline by repetitively pulsed charge-limited electrolysis for the production of oxygen and suppression of free chlorine. For example, using 800 A amplitude current pulses and <200 sec pulse durations, we demonstrated prompt oxygen production and delayed chlorine production at the surface of a shiny 0.85 mm diameter spherical platinum electrode. The data, interpreted in terms of the ionic structure of the electric double layer, suggest a strategy for in situ production of metabolic oxygen via a new class of "smart" prosthetic implants for dealing with ischemic disease such as diabetic retinopathy. We also present data indicating that drift of the local pH of the oxygenated environment can be held constant using a feedback-controlled three electrode electrolysis system that chooses anode and cathode pair based on pH data provided by local microsensors. The work is discussed in the context of diabetic retinopathy since surgical techniques for multielectrode prosthetic implants aimed at retinal degenerative diseases have been developed.

  6. Near-infrared spectroscopy for monitoring muscle oxygenation

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Piantadosi, C A

    2000-01-01

    Near-infrared spectroscopy (NIRS) is a non-invasive method for monitoring oxygen availability and utilization by the tissues. In intact skeletal muscle, NIRS allows semi-quantitative measurements of haemoglobin plus myoglobin oxygenation (tissue O2 stores) and the haemoglobin volume. Specialized...... algorithms allow assessment of the oxidation-reduction (redox) state of the copper moiety (CuA) of mitochondrial cytochrome c oxidase and, with the use of specific tracers, accurate assessment of regional blood flow. NIRS has demonstrated utility for monitoring changes in muscle oxygenation and blood flow...... during submaximal and maximal exercise and under pathophysiological conditions including cardiovascular disease and sepsis. During work, the extent to which skeletal muscles deoxygenate varies according to the type of muscle, type of exercise and blood flow response. In some instances, a strong...

  7. Hemodynamic parameters change earlier than tissue oxygen tension in hemorrhage.

    Science.gov (United States)

    Pestel, Gunther J; Fukui, Kimiko; Kimberger, Oliver; Hager, Helmut; Kurz, Andrea; Hiltebrand, Luzius B

    2010-05-15

    Untreated hypovolemia results in impaired outcome. This study tests our hypothesis whether general hemodynamic parameters detect acute blood loss earlier than monitoring parameters of regional tissue beds. Eight pigs (23-25 kg) were anesthetized and mechanically ventilated. A pulmonary artery catheter and an arterial catheter were inserted. Tissue oxygen tension was measured with Clark-type electrodes in the jejunal and colonic wall, in the liver, and subcutaneously. Jejunal microcirculation was assessed by laser Doppler flowmetry (LDF). Intravascular volume was optimized using difference in pulse pressure (dPP) to keep dPP below 13%. Sixty minutes after preparation, baseline measurements were taken. At first, 5% of total blood volume was withdrawn, followed by another 5% increment, and then in 10% increments until death. After withdrawal of 5% of estimated blood volume, dPP increased from 6.1% +/- 3.0% to 20.8% +/- 2.7% (P < 0.01). Mean arterial pressure (MAP), mean pulmonary artery pressure (PAP) and pulmonary artery occlusion pressure (PAOP) decreased with a blood loss of 10% (P < 0.01). Cardiac output (CO) changed after a blood loss of 20% (P < 0.05). Tissue oxygen tension in central organs, and blood flow in the jejunal muscularis decreased (P < 0.05) after a blood loss of 20%. Tissue oxygen tension in the skin, and jejunal mucosa blood flow decreased (P < 0.05) after a blood loss of 40% and 50%, respectively. In this hemorrhagic pig model systemic hemodynamic parameters were more sensitive to detect acute hypovolemia than tissue oxygen tension measurements or jejunal LDF measurements. Acute blood loss was detected first by dPP. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  8. Multispectral imaging of acute wound tissue oxygenation

    Directory of Open Access Journals (Sweden)

    Audrey Huong

    2017-05-01

    Full Text Available This paper investigates the appropriate range of values for the transcutaneous blood oxygen saturation (StO2 of granulating tissues and the surrounding tissue that can ensure timely wound recovery. This work has used a multispectral imaging system to collect wound images at wavelengths ranging between 520nm and 600nm with a resolution of 10nm. As part of this research, a pilot study was conducted on three injured individuals with superficial wounds of different wound ages at different skin locations. The StO2 value predicted for the examined wounds using the Extended Modified Lambert–Beer model revealed a mean StO2 of 61±10.3% compared to 41.6±6.2% at the surrounding tissues, and 50.1±1.53% for control sites. These preliminary results contribute to the existing knowledge on the possible range and variation of wound bed StO2 that are to be used as indicators of the functioning of the vasomotion system and wound health. This study has concluded that a high StO2 of approximately 60% and a large fluctuation in this value should precede a good progression in wound healing.

  9. Implementing oxygen control in chip-based cell and tissue culture systems.

    Science.gov (United States)

    Oomen, Pieter E; Skolimowski, Maciej D; Verpoorte, Elisabeth

    2016-09-21

    Oxygen is essential in the energy metabolism of cells, as well as being an important regulatory parameter influencing cell differentiation and function. Interest in precise oxygen control for in vitro cultures of tissues and cells continues to grow, especially with the emergence of the organ-on-a-chip and the desire to emulate in vivo conditions. This was recently discussed in this journal in a Critical Review by Brennan et al. (Lab Chip (2014). DOI: ). Microfluidics can be used to introduce flow to facilitate nutrient supply to and waste removal from in vitro culture systems. Well-defined oxygen gradients can also be established. However, cells can quickly alter the oxygen balance in their vicinity. In this Tutorial Review, we expand on the Brennan paper to focus on the implementation of oxygen analysis in these systems to achieve continuous monitoring. Both electrochemical and optical approaches for the integration of oxygen monitoring in microfluidic tissue and cell culture systems will be discussed. Differences in oxygen requirements from one organ to the next are a challenging problem, as oxygen delivery is limited by its uptake into medium. Hence, we discuss the factors determining oxygen concentrations in solutions and consider the possible use of artificial oxygen carriers to increase dissolved oxygen concentrations. The selection of device material for applications requiring precise oxygen control is discussed in detail, focusing on oxygen permeability. Lastly, a variety of devices is presented, showing the diversity of approaches that can be employed to control and monitor oxygen concentrations in in vitro experiments.

  10. Oxygen radical microscopy in living plant tissues

    DEFF Research Database (Denmark)

    Kristiansen, Kim Anker; Møller, Ian Max; Schulz, Alexander

    the ROS production stems from the mitochondria and peroxisomes as is seen in animal cells. At the Bioimaging Center at KVL we employ different techniques to induce, detect and monitor ROS production, distribution and in and among living plant cells. Both confocal laser scanning microscopy and 2-photon......Reactive oxygen species (ROS) play a crucial role in a wide variety of processes. Initiation of many different cellular pathways, crosstalk between cells, developmental signalling in planta, programmed cell death and hypersensitive response in connection with plant-pathogen interactions are among...... the different roles ROS play. On the other hand ROS also cause damage to cellular components at sub-lethal to lethal levels. In photosynthesizing plants the major production of ROS origin from the chloroplast. ROS is a by product from the Photosystem I/II handling of light energy. In nonphotosynthesizing plants...

  11. A high reliability oxygen deficiency monitoring system

    International Nuclear Information System (INIS)

    Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

    1993-01-01

    The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

  12. A high reliability oxygen deficiency monitoring system

    International Nuclear Information System (INIS)

    Parry, R.; Claborn, G.; Haas, A.; Landis, R.; Page, W.; Smith, J.

    1993-05-01

    The escalating use of cryogens at national laboratories in general and accelerators in particular, along with the increased emphasis placed on personnel safety, mandates the development and installation of oxygen monitoring systems to insure personnel safety in the event of a cryogenic leak. Numerous vendors offer oxygen deficiency monitoring systems but fail to provide important features and/or flexibility. This paper describes a unique oxygen monitoring system developed for the Magnet Test Laboratory (MTL) at the Superconducting Super Collider Laboratory (SSCL). Features include: high reliability, oxygen cell redundancy, sensor longevity, simple calibration, multiple trip points, offending sensor audio and visual indication, global alarms for building evacuation, local and remote analog readout, event and analog data logging, EMAIL event notification, phone line voice status system, and multi-drop communications network capability for reduced cable runs. Of particular importance is the distributed topology of the system which allows it to operate in a stand-alone configuration or to communicate with a host computer. This flexibility makes it ideal for small applications such as a small room containing a cryogenic dewar, as well as larger systems which monitor many offices and labs in several buildings

  13. Intraoperative transfusion threshold and tissue oxygenation

    DEFF Research Database (Denmark)

    Nielsen, K; Dahl, B; Johansson, P I

    2012-01-01

    Transfusion with allogeneic red blood cells (RBCs) may be needed to maintain oxygen delivery during major surgery, but the appropriate haemoglobin (Hb) concentration threshold has not been well established. We hypothesised that a higher level of Hb would be associated with improved subcutaneous...... oxygen tension during major spinal surgery....

  14. Increased tissue oxygenation explains the attenuation of hyperemia upon repetitive pneumatic compression of the lower leg.

    Science.gov (United States)

    Messere, Alessandro; Ceravolo, Gianluca; Franco, Walter; Maffiodo, Daniela; Ferraresi, Carlo; Roatta, Silvestro

    2017-12-01

    The rapid hyperemia evoked by muscle compression is short lived and was recently shown to undergo a rapid decrease even in spite of continuing mechanical stimulation. The present study aims at investigating the mechanisms underlying this attenuation, which include local metabolic mechanisms, desensitization of mechanosensitive pathways, and reduced efficacy of the muscle pump. In 10 healthy subjects, short sequences of mechanical compressions ( n = 3-6; 150 mmHg) of the lower leg were delivered at different interstimulus intervals (ranging from 20 to 160 s) through a customized pneumatic device. Hemodynamic monitoring included near-infrared spectroscopy, detecting tissue oxygenation and blood volume in calf muscles, and simultaneous echo-Doppler measurement of arterial (superficial femoral artery) and venous (femoral vein) blood flow. The results indicate that 1 ) a long-lasting (>100 s) increase in local tissue oxygenation follows compression-induced hyperemia, 2 ) compression-induced hyperemia exhibits different patterns of attenuation depending on the interstimulus interval, 3 ) the amplitude of the hyperemia is not correlated with the amount of blood volume displaced by the compression, and 4 ) the extent of attenuation negatively correlates with tissue oxygenation ( r  = -0,78, P < 0.05). Increased tissue oxygenation appears to be the key factor for the attenuation of hyperemia upon repetitive compressive stimulation. Tissue oxygenation monitoring is suggested as a useful integration in medical treatments aimed at improving local circulation by repetitive tissue compression. NEW & NOTEWORTHY This study shows that 1 ) the hyperemia induced by muscle compression produces a long-lasting increase in tissue oxygenation, 2 ) the hyperemia produced by subsequent muscle compressions exhibits different patterns of attenuation at different interstimulus intervals, and 3 ) the extent of attenuation of the compression-induced hyperemia is proportional to the level of

  15. [Tissue oxygen saturation in the critically ill patient].

    Science.gov (United States)

    Gruartmoner, G; Mesquida, J; Baigorri, F

    2014-05-01

    Hemodynamic resuscitation seeks to correct global macrocirculatory parameters of pressure and flow. However, current evidence has shown that despite the normalization of these global parameters, microcirculatory and regional perfusion alterations can persist, and these alterations have been independently associated with a poorer patient prognosis. This in turn has lead to growing interest in new technologies for exploring regional circulation and microcirculation. Near infra-red spectroscopy allows us to monitor tissue oxygen saturation, and has been proposed as a noninvasive, continuous and easy-to-obtain measure of regional circulation. The present review aims to summarize the existing evidence on near infra-red spectroscopy and its potential clinical role in the resuscitation of critically ill patients in shock. Copyright © 2013 Elsevier España, S.L. and SEMICYUC. All rights reserved.

  16. Monitoring Detrusor Oxygenation and Hemodynamics Noninvasively during Dysfunctional Voiding

    Science.gov (United States)

    Macnab, Andrew J.; Stothers, Lynn S.; Shadgan, Babak

    2012-01-01

    The current literature indicates that lower urinary tract symptoms (LUTSs) related to benign prostatic hyperplasia (BPH) have a heterogeneous pathophysiology. Pressure flow studies (UDSs) remain the gold standard evaluation methodology for such patients. However, as the function of the detrusor muscle depends on its vasculature and perfusion, the underlying causes of LUTS likely include abnormalities of detrusor oxygenation and hemodynamics, and available treatment options include agents thought to act on the detrusor smooth muscle and/or vasculature. Hence, near infrared spectroscopy (NIRS), an established optical methodology for monitoring changes in tissue oxygenation and hemodynamics, has relevance as a means of expanding knowledge related to the pathophysiology of BPH and potential treatment options. This methodological report describes how to conduct simultaneous NIRS monitoring of detrusor oxygenation and hemodynamics during UDS, outlines the clinical implications and practical applications of NIRS, explains the principles of physiologic interpretation of NIRS voiding data, and proposes an exploratory hypothesis that the pathophysiological causes underlying LUTS include detrusor dysfunction due to an abnormal hemodynamic response or the onset of oxygen debt during voiding. PMID:23019422

  17. Monitoring Detrusor Oxygenation and Hemodynamics Noninvasively during Dysfunctional Voiding

    Directory of Open Access Journals (Sweden)

    Andrew J. Macnab

    2012-01-01

    Full Text Available The current literature indicates that lower urinary tract symptoms (LUTSs related to benign prostatic hyperplasia (BPH have a heterogeneous pathophysiology. Pressure flow studies (UDSs remain the gold standard evaluation methodology for such patients. However, as the function of the detrusor muscle depends on its vasculature and perfusion, the underlying causes of LUTS likely include abnormalities of detrusor oxygenation and hemodynamics, and available treatment options include agents thought to act on the detrusor smooth muscle and/or vasculature. Hence, near infrared spectroscopy (NIRS, an established optical methodology for monitoring changes in tissue oxygenation and hemodynamics, has relevance as a means of expanding knowledge related to the pathophysiology of BPH and potential treatment options. This methodological report describes how to conduct simultaneous NIRS monitoring of detrusor oxygenation and hemodynamics during UDS, outlines the clinical implications and practical applications of NIRS, explains the principles of physiologic interpretation of NIRS voiding data, and proposes an exploratory hypothesis that the pathophysiological causes underlying LUTS include detrusor dysfunction due to an abnormal hemodynamic response or the onset of oxygen debt during voiding.

  18. Measuring oxidation processes: Atomic oxygen flux monitor

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    Of the existing 95 high-energy accelerators in the world, the Stanford Linear Collider (SLC) at the Stanford Linear Accelerator Center (SLAC) is the only one of the linear-collider type, where electrons and positrons are smashed together at energies of 50 GeV using linear beams instead of beam rings for achieving interactions. Use of a collider eliminates energy losses in the form of x-rays due to the curved trajectory of the rings, a phenomena known as bremsstrauhlung. Because these losses are eliminated, higher interaction energies are reached. Consequently the SLC produced the first Z particle in quantities large enough to allow measurement of its physical properties with some accuracy. SLAC intends to probe still deeper into the structure of matter by next polarizing the electrons in the beam. The surface of the source for these polarized particles, typically gallium arsenide, must be kept clean of contaminants. One method for accomplishing this task requires the oxidation of the surface, from which the oxidized contaminants are later boiled off. The technique requires careful measurement of the oxidation process. SLAC researchers have developed a technique for measuring the atomic oxygen flux in this process. The method uses a silver film on a quartz-crystal, deposition-rate monitor. Measuring the initial oxidation rate of the silver, which is proportional to the atomic oxygen flux, determines a lower limit on that flux in the range of 10 13 to 10 17 atoms per square centimeter per second. Furthermore, the deposition is reversible by exposing the sensor to atomic hydrogen. This technique has wider applications to processes in solid-state and surface physics as well as surface chemistry. In semiconductor manufacturing where a precise thickness of oxide must be deposited, this technique could be used to monitor the critical flux of atomic oxygen in the process

  19. Multiparametric monitoring of tissue vitality in clinical situations

    Science.gov (United States)

    Mayevsky, Avraham; Manor, Tamar; Meilin, Sigal; Razon, Nisim; Ouknine, George E.; Ornstein, Eugene

    2001-05-01

    The monitoring of various tissue's physiological and biochemical parameters is one of the tools used by the clinicians to improve diagnosis capacity. As of today, the very few devices developed for real time clinical monitoring of tissue vitality are based on a single parameter measurement. Tissue energy balance could be defined as the ratio between oxygen or energy supply and demand. In order to determine the vitality of the brain, for example, it is necessary to measure at least the following 3 parameters: Energy Demand--potassium ion homeostasis; Energy Supply-- cerebral blood flow; Energy Balance--mitochondrial NADH redox state. For other tissues one can measure various energy demand processes specific to the tested organ. We have developed a unique multiparametric monitoring system tested in various experimental and clinical applications. The multiprobe assembly (MPA) consists of a fiber optic probe for measurement of tissue blood flow and mitochondrial NADH redox state, ion selective electrodes (K+, Ca2+, H+), electrodes for electrical activities (ECoG or ECG and DC potential), temperature probe and for monitoring the brain - Intra Cranial Pressure probe (ICP). The computerized monitoring system was used in the neurological intensive care unit to monitor comatose patients for a period of 24-48 hours. Also, a simplified MPA was used in the neurosurgical operating room or during organ transplantation procedure. It was found that the MPA could be used in clinical situations and that the data collected has a significant diagnosis value for the medical team.

  20. Holographic monitoring of spatial distributions of singlet oxygen in water

    Science.gov (United States)

    Belashov, A. V.; Bel'tyukova, D. M.; Vasyutinskii, O. S.; Petrov, N. V.; Semenova, I. V.; Chupov, A. S.

    2014-12-01

    A method for monitoring spatial distributions of singlet oxygen in biological media has been developed. Singlet oxygen was generated using Radachlorin® photosensitizer, while thermal disturbances caused by nonradiative deactivation of singlet oxygen were detected by the holographic interferometry technique. Processing of interferograms yields temperature maps that characterize the deactivation process and show the distribution of singlet oxygen species.

  1. Association of intraoperative tissue oxygenation with suspected risk factors for tissue hypoxia.

    Science.gov (United States)

    Spruit, R J; Schwarte, L A; Hakenberg, O W; Scheeren, T W L

    2013-10-01

    Tissue hypoxia may cause organ dysfunction, but not much is known about tissue oxygenation in the intraoperative setting. We studied microcirculatory tissue oxygen saturation (StO₂) to determine representative values for anesthetized patients undergoing urological surgery and to test the hypothesis that StO₂ is associated with known perioperative risk factors for morbidity and mortality, conventionally monitored variables, and hypotension requiring norepinephrine. Using near-infrared spectroscopy, we measured StO₂ on the thenar eminence in 160 patients undergoing open urological surgery under general anesthesia (FiO2 0.35-0.4), and calculated its correlations with age, risk level for general perioperative complications and mortality (high if age ≥70 and procedure is radical cystectomy), mean arterial pressure (MAP), hemoglobin concentration (Hb), central venous oxygen saturation (ScvO₂), and norepinephrine use. The time averaged StO₂ was 86 ± 6 % (mean ± SD). In the multivariate analysis, Hb [standardized coefficient (SC) 0.21, p = 0.003], ScvO₂ (SC 0.53, p SStO₂ was partly dependent on MAP only when this was below 65 mmHg (lowest MAP SC 0.20, p = 0.006, MAP area under the curve <65 mmHg SC 0.03, p = 0.02). Finally, StO₂ was slightly lower in patients requiring norepinephrine (85 ± 6 vs. 89 ± 6 %, p = 0.001). Intraoperative StO₂ in urological patients was comparable to that of healthy volunteers breathing room air as reported in the literature and correlated with known perioperative risk factors. Further research should investigate its association with outcome and the effect of interventions aimed at optimizing StO₂.

  2. Improvement of Brain Tissue Oxygenation by Inhalation of Carbogen

    DEFF Research Database (Denmark)

    Ashkanian, M.; Borghammer, P.; Gjedde, A.

    2008-01-01

    tomography (PET) to measure CBF and cerebral metabolic rate of oxygen (CMRO(2)) during inhalation of test gases (O(2), CO(2), carbogen and atmospheric air) in 10 healthy volunteers. Arterial blood gases were recorded during administration of each gas. The data were analyzed with volume-of-interest and voxel...... is sufficient for optimal oxygenation of healthy brain tissue, whereas carbogen induces concomitant increases of CBF and Sa(O2)....

  3. Hyperspectral imaging solutions for brain tissue metabolic and hemodynamic monitoring: past, current and future developments

    Science.gov (United States)

    Giannoni, Luca; Lange, Frédéric; Tachtsidis, Ilias

    2018-04-01

    Hyperspectral imaging (HSI) technologies have been used extensively in medical research, targeting various biological phenomena and multiple tissue types. Their high spectral resolution over a wide range of wavelengths enables acquisition of spatial information corresponding to different light-interacting biological compounds. This review focuses on the application of HSI to monitor brain tissue metabolism and hemodynamics in life sciences. Different approaches involving HSI have been investigated to assess and quantify cerebral activity, mainly focusing on: (1) mapping tissue oxygen delivery through measurement of changes in oxygenated (HbO2) and deoxygenated (HHb) hemoglobin; and (2) the assessment of the cerebral metabolic rate of oxygen (CMRO2) to estimate oxygen consumption by brain tissue. Finally, we introduce future perspectives of HSI of brain metabolism, including its potential use for imaging optical signals from molecules directly involved in cellular energy production. HSI solutions can provide remarkable insight in understanding cerebral tissue metabolism and oxygenation, aiding investigation on brain tissue physiological processes.

  4. 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)

  5. Tissue oxygenation and haemodynamics measurement with spatially resolved NIRS

    Science.gov (United States)

    Zhang, Y.; Scopesi, F.; Serra, G.; Sun, J. W.; Rolfe, P.

    2010-08-01

    We describe the use of Near Infrared Spectroscopy (NIRS) for the non-invasive investigation of changes in haemodynamics and oxygenation of human peripheral tissues. The goal was to measure spatial variations of tissue NIRS oxygenation variables, namely deoxy-haemoglobin (HHb), oxy-haemoglobin (HbO2), total haemoglobin (HbT), and thereby to evaluate the responses of the peripheral circulation to imposed physiological challenges. We present a skinfat- muscle heterogeneous tissue model with varying fat thickness up to 15mm and a Monte Carlo simulation of photon transport within this model. The mean partial path length and the mean photon visit depth in the muscle layer were derived for different source-detector spacing. We constructed NIRS instrumentation comprising of light-emitting diodes (LED) as light sources at four wavelengths, 735nm, 760nm, 810nm and 850nm and sensitive photodiodes (PD) as the detectors. Source-detector spacing was varied to perform measurements at different depths within forearm tissue. Changes in chromophore concentration in response to venous and arterial occlusion were calculated using the modified Lambert-Beer Law. Studies in fat and thin volunteers indicated greater sensitivity in the thinner subjects for the tissue oxygenation measurement in the muscle layer. These results were consistent with those found using Monte Carlo simulation. Overall, the results of this investigation demonstrate the usefulness of the NIRS instrument for deriving spatial information from biological tissues.

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

    OpenAIRE

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

    2013-01-01

    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 ...

  7. "Tissue oxygen tension, a determinant of resistance to infection and ...

    African Journals Online (AJOL)

    "Tissue oxygen tension, a determinant of resistance to infection and healing" - An Inaugural Lecture. K Jönsson. Abstract. An Inaugural Lecture Given in the University of Zimbabwe on 21 June 2001. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT.

  8. 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.

  9. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates

    International Nuclear Information System (INIS)

    Pichler, Gerhard; Pocivalnik, Mirjam; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt; Riedl, Regina

    2011-01-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO 2 ), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO 2 ), oxygen consumption (VO 2 ), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO 2 ), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO 2 ) were calculated. All demographic parameters except for Hbflow and DO 2 correlated with NIRS parameters. Heart rate correlated with TOI, SvO 2 , VO 2 and VR. SaO 2 correlated with FOE/FTOE. MAP correlated with Hbflow, DO 2 , VO 2 and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO 2 . Hb-blood correlated with FOE and VR. pCO 2 levels correlated with TOI and SvO 2 . The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data

  10. 'Multi-associations': predisposed to misinterpretation of peripheral tissue oxygenation and circulation in neonates.

    Science.gov (United States)

    Pichler, Gerhard; Pocivalnik, Mirjam; Riedl, Regina; Pichler-Stachl, Elisabeth; Morris, Nicholas; Zotter, Heinz; Müller, Wilhelm; Urlesberger, Berndt

    2011-08-01

    Interpretation of peripheral circulation in ill neonates is crucial but difficult. The aim was to analyse parameters potentially influencing peripheral oxygenation and circulation. In a prospective observational cohort study in 116 cardio-circulatory stable neonates, peripheral muscle near-infrared spectroscopy (NIRS) with venous occlusion was performed. Tissue oxygenation index (TOI), mixed venous oxygenation (SvO(2)), fractional oxygen extraction (FOE), fractional tissue oxygen extraction (FTOE), haemoglobin flow (Hbflow), oxygen delivery (DO(2)), oxygen consumption (VO(2)), and vascular resistance (VR) were assessed. Correlation coefficients between NIRS parameters and demographic parameters (gestational age, birth weight, age, actual weight, diameter of calf, subcutaneous adipose tissue), monitoring parameters (heart rate, arterial oxygen saturation (SaO(2)), mean blood pressure (MAP), core/peripheral temperature, central/peripheral capillary refill time) and laboratory parameters (haemoglobin concentration (Hb-blood), pCO(2)) were calculated. All demographic parameters except for Hbflow and DO(2) correlated with NIRS parameters. Heart rate correlated with TOI, SvO(2), VO(2) and VR. SaO(2) correlated with FOE/FTOE. MAP correlated with Hbflow, DO(2), VO(2) and VR. Core temperature correlated with FTOE. Peripheral temperature correlated with all NIRS parameters except VO(2). Hb-blood correlated with FOE and VR. pCO(2) levels correlated with TOI and SvO(2). The presence of multiple interdependent factors associated with peripheral oxygenation and circulation highlights the difficulty in interpreting NIRS data. Nevertheless, these findings have to be taken into account when analysing peripheral oxygenation and circulation data.

  11. Prognostic value of cerebral tissue oxygen saturation during neonatal extracorporeal membrane oxygenation.

    Directory of Open Access Journals (Sweden)

    Marie-Philippine Clair

    Full Text Available Extracorporeal membrane oxygenation support is indicated in severe and refractory respiratory or circulatory failures. Neurological complications are typically represented by acute ischemic or hemorrhagic lesions, which induce higher morbidity and mortality. The primary goal of this study was to assess the prognostic value of cerebral tissue oxygen saturation (StcO2 on mortality in neonates and young infants treated with ECMO. A secondary objective was to evaluate the association between StcO2 and the occurrence of cerebral lesions.This was a prospective study in infants < 3 months of age admitted to a pediatric intensive care unit and requiring ECMO support.The assessment of cerebral perfusion was made by continuous StcO2 monitoring using near-infrared spectroscopy (NIRS sensors placed on the two temporo-parietal regions. Neurological lesions were identified by MRI or transfontanellar echography.Thirty-four infants <3 months of age were included in the study over a period of 18 months. The ECMO duration was 10±7 days. The survival rate was 50% (17/34 patients, and the proportion of brain injuries was 20% (7/34 patients. The mean StcO2 during ECMO in the non-survivors was reduced in both hemispheres (p = 0.0008 right, p = 0.03 left compared to the survivors. StcO2 was also reduced in deceased or brain-injured patients compared to the survivors without brain injury (p = 0.002.StcO2 appears to be a strong prognostic factor of survival and of the presence of cerebral lesions in young infants during ECMO.

  12. 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.

  13. Monitoring soft tissue coagulation by optical spectroscopy

    Science.gov (United States)

    Lihachev, A.; Lihacova, I.; Heinrichs, H.; Spigulis, J.; Trebst, T.; Wehner, M.

    2017-12-01

    Laser tissue welding (LTW) or laser tissue soldering (LTS) is investigated since many years for treatment of incisions, wound closure and anastomosis of vessels [1, 2]. Depending on the process, a certain temperature in the range between 65 °C to 85 °C must be reached and held for a few seconds. Care has to be taken not to overheat the tissue, otherwise necrosis or tissue carbonization may occur and will impair wound healing. Usually the temperature is monitored during the process to control the laser power [3]. This requires either bulky equipment or expensive and fragile infrared fibers to feed the temperature signal to an infrared detector. Alternatively, changes in tissue morphology can be directly observed by analysis of spectral reflectance. We investigate spectral changes in the range between 400 nm to 900 nm wavelength. Characteristic spectral changes occur when the temperature of tissue samples increase above 70 °C which is a typical setpoint value for temperature control of coagulation. We conclude that simple spectroscopy in the visible range can provide valuable information during LTS and LTW and probably replace the delicate measurement of temperature. A major advantage is that optical measurements can be performed using standard optical fibers and can be easily integrated into a surgical tool.

  14. Oxygen and tissue culture affect placental gene expression.

    Science.gov (United States)

    Brew, O; Sullivan, M H F

    2017-07-01

    Placental explant culture is an important model for studying placental development and functions. We investigated the differences in placental gene expression in response to tissue culture, atmospheric and physiologic oxygen concentrations. Placental explants were collected from normal term (38-39 weeks of gestation) placentae with no previous uterine contractile activity. Placental transcriptomic expressions were evaluated with GeneChip ® Human Genome U133 Plus 2.0 arrays (Affymetrix). We uncovered sub-sets of genes that regulate response to stress, induction of apoptosis programmed cell death, mis-regulation of cell growth, proliferation, cell morphogenesis, tissue viability, and protection from apoptosis in cultured placental explants. We also identified a sub-set of genes with highly unstable pattern of expression after exposure to tissue culture. Tissue culture irrespective of oxygen concentration induced dichotomous increase in significant gene expression and increased enrichment of significant pathways and transcription factor targets (TFTs) including HIF1A. The effect was exacerbated by culture at atmospheric oxygen concentration, where further up-regulation of TFTs including PPARA, CEBPD, HOXA9 and down-regulated TFTs such as JUND/FOS suggest intrinsic heightened key biological and metabolic mechanisms such as glucose use, lipid biosynthesis, protein metabolism; apoptosis, inflammatory responses; and diminished trophoblast proliferation, differentiation, invasion, regeneration, and viability. These findings demonstrate that gene expression patterns differ between pre-culture and cultured explants, and the gene expression of explants cultured at atmospheric oxygen concentration favours stressed, pro-inflammatory and increased apoptotic transcriptomic response. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Effects of acupuncture on tissue oxygenation of the rat brain.

    Science.gov (United States)

    Chen, G S; Erdmann, W

    1978-04-01

    Acupuncture has been claimed to be effective in restoring consciousness in some comatose patients. Possible mechanisms to explain alleged acupuncture-induced arousal may include vasodilatory effects caused by smypathetic stimulation which leads to an augmentation of cerebral microcirculation and thereby improves oxygen supply to the brain tissue. Experiments were performed in ten albino rats (Wistar) employing PO2 microelectrodes which were inserted into the cortex through small burholes. Brain tissue PO2 was continuously recorded before, during, and after acupuncture. Stimulation of certain acupuncture points (Go-26) resulted in immediate increase of PO2 in the frontal cortex of the rat brain. This effect was reproducible and was comparable to that obtained with increase of inspiratory CO2 known to induce arterial vasodilatation and thus capillary perfusion pressure. The effect was more significant as compared to tissue PO2 increases obtained after increase in inspiratory oxygen concentration from 21% to 100%. It appears that acupuncture causes increased brain tissue perfusion which may be, at least in part, responsible for arousal of unconscious patients.

  17. 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.

  18. Crew Cerebral Oxygen Monitor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase I SBIR proposal is aimed at developing a non-invasive, optical method for monitoring the state of consciousness of crew members in operational...

  19. Crew Cerebral Oxygen Monitor, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This Phase II SBIR proposal is aimed at developing a non-invasive, optical method for monitoring crew member state of awareness in operational environments. All...

  20. Monitoring bioremediation of weathered diesel NAPL using oxygen depletion profiles

    International Nuclear Information System (INIS)

    Davis, G.B.; Johnston, C.D.; Patterson, B.M.; Barber, C.; Bennett, M.

    1995-01-01

    Semicontinuous logging of oxygen concentrations at multiple depths has been used to evaluate the progress of an in situ bioremediation trial at a site contaminated by weathered diesel nonaqueous-phase liquid (NAPL). The evaluation trial consisted of periodic addition of nutrients and aeration of a 100-m 2 trial plot. During the bioremediation trial, aeration was stopped periodically, and decreases in dissolved and gaseous oxygen concentrations were monitored using data loggers attached to in situ oxygen sensors placed at multiple depths above and within a thin NAPL-contaminated zone. Oxygen usage rate coefficients were determined by fitting zero- and first-order rate equations to the oxygen depletion curves. For nutrient-amended sites within the trial plot, estimates of oxygen usage rate coefficients were significantly higher than estimates from unamended sites. These rates also converted to NPL degradation rates, comparable to those achieved in previous studies, despite the high concentrations and weathered state of the NAPL at this test site

  1. A fibre-optic oxygen sensor for monitoring human breathing

    International Nuclear Information System (INIS)

    Chen, Rongsheng; Formenti, Federico; Hahn, Clive E W; Farmery, Andrew D; Obeid, Andy

    2013-01-01

    The development and construction of a tapered-tip fibre-optic fluorescence based oxygen sensor is described. The sensor is suitable for fast and real-time monitoring of human breathing. The sensitivity and response time of the oxygen sensor were evaluated in vitro with a gas pressure chamber system, where oxygen partial pressure was rapidly changed between 5 and 15 kPa, and then in vivo in five healthy adult participants who synchronized their breathing to a metronome set at 10, 20, 30, 40, 50, and 60 breaths min –1 . A Datex Ultima medical gas analyser was used to monitor breathing rate as a comparator. The sensor's response time in vitro was less than 150 ms, which allows accurate continuous measurement of inspired and expired oxygen pressure. Measurements of breathing rate by means of our oxygen sensor and of the Datex Ultima were in strong agreement. The results demonstrate that the device can reliably resolve breathing rates up to 60 breaths min –1 , and that it is a suitable cost-effective alternative for monitoring breathing rates and end-tidal oxygen partial pressure in the clinical setting. The rapid response time of the sensor may allow its use for monitoring rapid breathing rates as occur in children and the newborn. (note)

  2. Tissue oxygen demand in regulation of the behavior of the cells in the vasculature.

    Science.gov (United States)

    Barvitenko, Nadezhda N; Aslam, Muhammad; Filosa, Jessica; Matteucci, Elena; Nikinmaa, Mikko; Pantaleo, Antonella; Saldanha, Carlota; Baskurt, Oguz K

    2013-08-01

    The control of arteriolar diameters in microvasculature has been in the focus of studies on mechanisms matching oxygen demand and supply at the tissue level. Functionally, important vascular elements include EC, VSMC, and RBC. Integration of these different cell types into functional units aimed at matching tissue oxygen supply with tissue oxygen demand is only achieved when all these cells can respond to the signals of tissue oxygen demand. Many vasoactive agents that serve as signals of tissue oxygen demand have their receptors on all these types of cells (VSMC, EC, and RBC) implying that there can be a coordinated regulation of their behavior by the tissue oxygen demand. Such functions of RBC as oxygen carrying by Hb, rheology, and release of vasoactive agents are considered. Several common extra- and intracellular signaling pathways that link tissue oxygen demand with control of VSMC contractility, EC permeability, and RBC functioning are discussed. © 2013 John Wiley & Sons Ltd.

  3. A technique for measuring oxygen saturation in biological tissues based on diffuse optical spectroscopy

    Science.gov (United States)

    Kleshnin, Mikhail; Orlova, Anna; Kirillin, Mikhail; Golubiatnikov, German; Turchin, Ilya

    2017-07-01

    A new approach to optical measuring blood oxygen saturation was developed and implemented. This technique is based on an original three-stage algorithm for reconstructing the relative concentration of biological chromophores (hemoglobin, water, lipids) from the measured spectra of diffusely scattered light at different distances from the probing radiation source. The numerical experiments and approbation of the proposed technique on a biological phantom have shown the high reconstruction accuracy and the possibility of correct calculation of hemoglobin oxygenation in the presence of additive noise and calibration errors. The obtained results of animal studies have agreed with the previously published results of other research groups and demonstrated the possibility to apply the developed technique to monitor oxygen saturation in tumor tissue.

  4. The nursing perspective on monitoring hemodynamics and oxygen transport.

    Science.gov (United States)

    Tucker, Dawn; Hazinski, Mary Fran

    2011-07-01

    Maintenance of adequate systemic oxygen delivery requires careful clinical assessment integrated with hemodynamic measurements and calculations to detect and treat conditions that may compromise oxygen delivery and lead to life-threatening shock, respiratory failure, or cardiac arrest. The bedside nurse constantly performs such assessments and measurements to detect subtle changes and trends in patient condition. The purpose of this editorial is to highlight nursing perspectives about the hemodynamic and oxygen transport monitoring systems summarized in the Pediatric Cardiac Intensive Care Society Evidence- Based Review and Consensus Statement on Monitoring of Hemodynamics and Oxygen Transport Balance. There is no substitute for the observations of a knowledgeable and experienced clinician who understands the patient's condition and potential causes of deterioration and is able to evaluate response to therapy.

  5. A fibre optic oxygen sensor for monitoring of human breathing

    Science.gov (United States)

    Chen, Rongsheng; Farmery, Andrew D.; Chen, Rui; Hahn, Clive E. W.

    2011-11-01

    A reliable and cost effective fibre optic oxygen sensor for monitoring of human breathing has been developed using a normal 200μm silica core/silica cladding optical fibre and a polymer sensing matrix. The fibre optic oxygen sensor is based on the fluorescence quenching of a fluorophore by oxygen. The sensing matrix, containing immobilized Pt(II) complexes, was coated at the end of the silica core/silica cladding optical fibre. The sensitivity and time response of the sensor were evaluated using the method of luminescence lifetime measurement. The polymer substrate influence on the time response of the sensor was improved by using a fibre taper design, and the response time of the optimized sensor was less than 200ms. This silica fibre based optic oxygen sensor is suitable for monitoring of patient breathing in intensive care unit in terms of safety and low cost.

  6. A method for volumetric retinal tissue oxygen tension imaging.

    Science.gov (United States)

    Felder, Anthony E; Wanek, Justin; Teng, Pang-Yu; Blair, Norman P; Shahidi, Mahnaz

    2018-01-01

    Inadequate retinal oxygenation occurs in many vision-threatening retinal diseases, including diabetic retinopathy, retinal vascular occlusions, and age-related macular degeneration. Therefore, techniques that assess retinal oxygenation are necessary to understand retinal physiology in health and disease. The purpose of the current study is to report a method for the three-dimensional (3D) imaging of retinal tissue oxygen tension (tPO 2 ) in rats. Imaging was performed in Long Evans pigmented rats under systemic normoxia (N = 6) or hypoxia (N = 3). A vertical laser line was horizontally scanned on the retina and a series of optical section phase-delayed phosphorescence images were acquired. From these images, phosphorescence volumes at each phase delay were constructed and a 3D retinal tPO 2 volume was generated. Retinal tPO 2 volumes were quantitatively analyzed by generating retinal depth profiles of mean tPO 2 (M tPO2 ) and the spatial variation of tPO 2 (SV tPO2 ). The effects of systemic condition (normoxia/hypoxia) and retinal depth on M tPO2 and SV tPO2 were determined by mixed linear model. Each 3D retinal tPO 2 volume was approximately 500 × 750 × 200 μm (horizontal × vertical × depth) and consisted of 45 en face tPO 2 images through the retinal depth. M tPO2 at the chorioretinal interface was significantly correlated with systemic arterial oxygen tension (P = 0.007; N = 9). There were significant effects of both systemic condition and retinal depth on M tPO2 and SV tPO2 , such that both were lower under hypoxia than normoxia and higher in the outer retina than inner retina (P < 0.001). For the first time, 3D imaging of retinal tPO 2 was demonstrated, with potential future application for assessment of physiological alterations in animal models of retinal diseases.

  7. Correlation of cutaneous tension distribution and tissue oxygenation with acute external tissue expansion

    Directory of Open Access Journals (Sweden)

    Marquardt C

    2009-11-01

    Full Text Available Abstract Today, the biomechanical fundamentals of skin expansion are based on viscoelastic models of the skin. Although many studies have been conducted in vitro, analyses performed in vivo are rare. Here, we present in vivo measurements of the expansion at the skin surface as well as measurement of the corresponding intracutaneous oxygen partial pressure. In our study the average skin stretching was 24%, with a standard deviation of 11%, excluding age or gender dependency. The measurement of intracutaneous oxygen partial pressure produced strong inter-individual fluctuations, including initial values at the beginning of the measurement, as well as varying individual patient reactions to expansion of the skin. Taken together, we propose that even large defect wounds can be closed successfully using the mass displacement caused by expansion especially in areas where soft, voluminous tissue layers are present.

  8. 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

  9. Real-time changes in brain tissue oxygen during endovascular treatment of cerebral vasospasm

    DEFF Research Database (Denmark)

    Rasmussen, Rune; Bache, Søren; Stavngaard, Trine

    2015-01-01

    pressure (PtiO₂) in target parenchyma. However, during the intervention, dangerously low levels of brain tissue oxygen, leading to cerebral infarction, may occur. Thus, no clinical improvement was seen in two of the patients and a dramatic worsening was observed in the third patient. Because the decrease...... minute-by-minute changes in brain tissue oxygen during balloon angioplasty and intraarterial administration of vasodilators in three patients.Our results confirm that endovascular intervention is capable of not only resolving angiographic vasospasm, but also of normalizing values of brain tissue oxygen...... in brain tissue oxygen was seen after administration of vasopressor agents, this may be a contributing factor....

  10. Spatial sensitivity and penetration depth of three cerebral oxygenation monitors

    Science.gov (United States)

    Gunadi, Sonny; Leung, Terence S.; Elwell, Clare E.; Tachtsidis, Ilias

    2014-01-01

    The spatial sensitivities of NIRO-100, ISS Oximeter and TRS-20 cerebral oxygenation monitors are mapped using the local perturbation method to inform on their penetration depths and susceptibilities to superficial contaminations. The results show that TRS-20 has the deepest mean penetration depth and is less sensitive than the other monitors to a localized absorption change in the superficial layer. However, an integration time of more than five seconds is required by the TRS-20 to achieve an acceptable level of signal-to-noise ratio, which is the poorest amongst the monitors. With the exception of NIRO-100 continuous wave method, the monitors are not significantly responsive to layer-wide absorption change that occurs in the superficial layer. PMID:25401006

  11. Noninvasive assessment of tissue-engineered graft viability by oxygen-17 magnetic resonance spectroscopy.

    Science.gov (United States)

    Einstein, Samuel A; Weegman, Bradley P; Kitzmann, Jennifer P; Papas, Klearchos K; Garwood, Michael

    2017-05-01

    Transplantation of macroencapsulated tissue-engineered grafts (TEGs) is being investigated as a treatment for type 1 diabetes, but there is a critical need to measure TEG viability both in vitro and in vivo. Oxygen deficiency is the most critical issue preventing widespread implementation of TEG transplantation and delivery of supplemental oxygen (DSO) has been shown to enhance TEG survival and function in vivo. In this study, we demonstrate the first use of oxygen-17 magnetic resonance spectroscopy ( 17 O-MRS) to measure the oxygen consumption rate (OCR) of TEGs and show that in addition to providing therapeutic benefits to TEGs, DSO with 17 O 2 can also enable measurements of TEG viability. Macroencapsulated TEGs containing βTC3 murine insulinoma cells were prepared with three fractional viabilities and provided with 17 O 2 . Cellular metabolism of 17 O 2 into nascent mitochondrial water (H 2 17 O) was monitored by 17 O-MRS and, from the measured data, OCR was calculated. For comparison, OCR was simultaneously measured on a separate, but equivalent sample of cells with a well-established stirred microchamber technique. OCR measured by 17 O-MRS agreed well with measurements made in the stirred microchamber device. These studies confirm that 17 O-MRS can quantify TEG viability noninvasively. Biotechnol. Bioeng. 2017;114: 1118-1121. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  12. Real-time optoacoustic monitoring of temperature in tissues

    International Nuclear Information System (INIS)

    Larina, Irina V; Larin, Kirill V; Esenaliev, Rinat O

    2005-01-01

    To improve the safety and efficacy of thermal therapy, it is necessary to map tissue temperature in real time with submillimetre spatial resolution. Accurate temperature maps may provide the necessary control of the boundaries of the heated regions and minimize thermal damage to surrounding normal tissues. Current imaging modalities fail to monitor tissue temperature in real time with high resolution and accuracy. We investigated a non-invasive optoacoustic method for accurate, real-time monitoring of tissue temperature during thermotherapy. In this study, we induced temperature gradients in tissue and tissue-like samples and monitored the temperature distribution using the optoacoustic technique. The fundamental harmonic of a Q-switched Nd : YAG laser (λ = 1064 nm) was used for optoacoustic wave generation and probing of tissue temperature. The tissue temperature was also monitored with a multi-sensor temperature probe inserted in the samples. Good agreement between optoacoustically measured and actual tissue temperatures was obtained. The accuracy of temperature monitoring was better than 1 0 C, while the spatial resolution was about 1 mm. These data suggest that the optoacoustic technique has the potential to be used for non-invasive, real-time temperature monitoring during thermotherapy

  13. 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

  14. 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

  15. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: Measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, Jeroen; Martens, D.E.; le Comte, EP; Kooy, F.K.; Tramper, J.; van Blitterswijk, Clemens; Riesle, J.U.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE cartilage polymer

  16. Oxygen gradients in tissue-engineered PEGT/PBT cartilaginous constructs: measurement and modeling

    NARCIS (Netherlands)

    Malda, J.; Rouwkema, J.; Martens, D.E.; Paul le Comte, E.; Kooy, F.K.; Tramper, J.; Blitterswijk, van C.A.; Riesle, J.

    2004-01-01

    The supply of oxygen within three-dimensional tissue-engineered (TE) cartilage polymer constructs is mainly by diffusion. Oxygen consumption by cells results in gradients in the oxygen concentration. The aims of this study were, firstly, to identify the gradients within TE: cartilage polymer

  17. Mitochondrial function and tissue vitality: bench-to-bedside real-time optical monitoring system

    Science.gov (United States)

    Mayevsky, Avraham; Walden, Raphael; Pewzner, Eliyahu; Deutsch, Assaf; Heldenberg, Eitan; Lavee, Jacob; Tager, Salis; Kachel, Erez; Raanani, Ehud; Preisman, Sergey; Glauber, Violete; Segal, Eran

    2011-06-01

    Background: The involvement of mitochondria in pathological states, such as neurodegenerative diseases, sepsis, stroke, and cancer, are well documented. Monitoring of nicotinamide adenine dinucleotide (NADH) fluorescence in vivo as an intracellular oxygen indicator was established in 1950 to 1970 by Britton Chance and collaborators. We use a multiparametric monitoring system enabling assessment of tissue vitality. In order to use this technology in clinical practice, the commercial developed device, the CritiView (CRV), is tested in animal models as well as in patients. Methods and Results: The new CRV enables the optical monitoring of four different parameters, representing the energy balance of various tissues in vivo. Mitochondrial NADH is measured by surface fluorometry/reflectometry. In addition, tissue microcirculatory blood flow, tissue reflectance and oxygenation are measured as well. The device is tested both in vitro and in vivo in a small animal model and in preliminary clinical trials in patients undergoing vascular or open heart surgery. In patients, the monitoring is started immediately after the insertion of a three-way Foley catheter (urine collection) to the patient and is stopped when the patient is discharged from the operating room. The results show that monitoring the urethral wall vitality provides information in correlation to the surgical procedure performed.

  18. Impedance-based monitoring for tissue engineering applications

    DEFF Research Database (Denmark)

    Canali, Chiara; Heiskanen, Arto; Martinsen, Ø.G.

    2015-01-01

    Impedance is a promising technique for sensing the overall process of tissue engineering. Different electrode configurations can be used to characterize the scaffold that supports cell organization in terms of hydrogel polymerization and degree of porosity, monitoring cell loading, cell...

  19. Further Controversies About Brain Tissue Oxygenation Pressure-Reactivity After Traumatic Brain Injury

    DEFF Research Database (Denmark)

    Andresen, Morten; Donnelly, Joseph; Aries, Marcel

    2018-01-01

    arterial pressure and intracranial pressure. A new ORx index based on brain tissue oxygenation and cerebral perfusion pressure (CPP) has been proposed that similarly allows for evaluation of cerebrovascular reactivity. Conflicting results exist concerning its clinical utility. METHODS: Retrospective......BACKGROUND: Continuous monitoring of cerebral autoregulation is considered clinically useful due to its ability to warn against brain ischemic insults, which may translate to a relationship with adverse outcome. It is typically performed using the pressure reactivity index (PRx) based on mean...... analysis was performed in 85 patients with traumatic brain injury (TBI). ORx was calculated using three time windows of 5, 20, and 60 min. Correlation coefficients and individual "optimal CPP" (CPPopt) were calculated using both PRx and ORx, and relation to patient outcome investigated. RESULTS...

  20. 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

  1. Why is the partial oxygen pressure of human tissues a crucial parameter? Small molecules and hypoxia

    Science.gov (United States)

    Carreau, Aude; Hafny-Rahbi, Bouchra El; Matejuk, Agata; Grillon, Catherine; Kieda, Claudine

    2011-01-01

    Abstract Oxygen supply and diffusion into tissues are necessary for survival. The oxygen partial pressure (pO2), which is a key component of the physiological state of an organ, results from the balance between oxygen delivery and its consumption. In mammals, oxygen is transported by red blood cells circulating in a well-organized vasculature. Oxygen delivery is dependent on the metabolic requirements and functional status of each organ. Consequently, in a physiological condition, organ and tissue are characterized by their own unique ‘tissue normoxia’ or ‘physioxia’ status. Tissue oxygenation is severely disturbed during pathological conditions such as cancer, diabetes, coronary heart disease, stroke, etc., which are associated with decrease in pO2, i.e. ‘hypoxia’. In this review, we present an array of methods currently used for assessing tissue oxygenation. We show that hypoxia is marked during tumour development and has strong consequences for oxygenation and its influence upon chemotherapy efficiency. Then we compare this to physiological pO2 values of human organs. Finally we evaluate consequences of physioxia on cell activity and its molecular modulations. More importantly we emphasize the discrepancy between in vivo and in vitro tissue and cells oxygen status which can have detrimental effects on experimental outcome. It appears that the values corresponding to the physioxia are ranging between 11% and 1% O2 whereas current in vitro experimentations are usually performed in 19.95% O2, an artificial context as far as oxygen balance is concerned. It is important to realize that most of the experiments performed in so-called normoxia might be dangerously misleading. PMID:21251211

  2. Why is the partial oxygen pressure of human tissues a crucial parameter? Small molecules and hypoxia.

    Science.gov (United States)

    Carreau, Aude; El Hafny-Rahbi, Bouchra; Matejuk, Agata; Grillon, Catherine; Kieda, Claudine

    2011-06-01

    Oxygen supply and diffusion into tissues are necessary for survival. The oxygen partial pressure (pO(2)), which is a key component of the physiological state of an organ, results from the balance between oxygen delivery and its consumption. In mammals, oxygen is transported by red blood cells circulating in a well-organized vasculature. Oxygen delivery is dependent on the metabolic requirements and functional status of each organ. Consequently, in a physiological condition, organ and tissue are characterized by their own unique 'tissue normoxia' or 'physioxia' status. Tissue oxygenation is severely disturbed during pathological conditions such as cancer, diabetes, coronary heart disease, stroke, etc., which are associated with decrease in pO(2), i.e. 'hypoxia'. In this review, we present an array of methods currently used for assessing tissue oxygenation. We show that hypoxia is marked during tumour development and has strong consequences for oxygenation and its influence upon chemotherapy efficiency. Then we compare this to physiological pO(2) values of human organs. Finally we evaluate consequences of physioxia on cell activity and its molecular modulations. More importantly we emphasize the discrepancy between in vivo and in vitro tissue and cells oxygen status which can have detrimental effects on experimental outcome. It appears that the values corresponding to the physioxia are ranging between 11% and 1% O(2) whereas current in vitro experimentations are usually performed in 19.95% O(2), an artificial context as far as oxygen balance is concerned. It is important to realize that most of the experiments performed in so-called normoxia might be dangerously misleading. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

  3. A Method for Combined Retinal Vascular and Tissue Oxygen Tension Imaging.

    Science.gov (United States)

    Felder, Anthony E; Wanek, Justin; Tan, Michael R; Blair, Norman P; Shahidi, Mahnaz

    2017-09-06

    The retina requires adequate oxygenation to maintain cellular metabolism and visual function. Inner retinal oxygen metabolism is directly related to retinal vascular oxygen tension (PO 2 ) and inner retinal oxygen extraction fraction (OEF), whereas outer retinal oxygen consumption (QO 2 ) relies on oxygen availability by the choroid and is contingent upon retinal tissue oxygen tension (tPO 2 ) gradients across the retinal depth. Thus far, these oxygenation and metabolic parameters have been measured independently by different techniques in separate animals, precluding a comprehensive and correlative assessment of retinal oxygenation and metabolism dynamics. The purpose of the current study is to report an innovative optical system for dual oxyphor phosphorescence lifetime imaging to near-simultaneously measure retinal vascular PO 2 and tPO 2 in rats. The use of a new oxyphor with different spectral characteristics allowed differentiation of phosphorescence signals from the retinal vasculature and tissue. Concurrent measurements of retinal arterial and venous PO 2 , tPO 2 through the retinal depth, inner retinal OEF, and outer retinal QO 2 were demonstrated, permitting a correlative assessment of retinal oxygenation and metabolism. Future application of this method can be used to investigate the relations among retinal oxygen content, extraction and metabolism under pathologic conditions and thus advance knowledge of retinal hypoxia pathophysiology.

  4. Optical monitoring of kidney oxygenation and hemodynamics using a miniaturized near-infrared sensor

    Science.gov (United States)

    Shadgan, Babak; Macnab, Andrew; Nigro, Mark; Nguan, Christopher

    2017-02-01

    Background: Following human renal allograft transplant primary graft dysfunction can occur early in the postoperative period as a result of acute tubular necrosis, acute rejection, drug toxicity, and vascular complications. Successful treatment of graft dysfunction requires early detection and accurate diagnosis so that disease-specific medical and/or surgical intervention can be provided promptly. However, current diagnostic methods are not sensitive or specific enough, so that identifying the cause of graft dysfunction is problematic and often delayed. Near-infrared spectroscopy (NIRS) is an established optical method that monitors changes in tissue hemodynamics and oxygenation in real time. We report the feasibility of directly monitoring kidney the kidney in an animal model using NIRS to detect renal ischemia and hypoxia. Methods: In an anesthetized pig, a customized continuous wave spatially resolved (SR) NIRS sensor was fixed directly to the surface of the surgically exposed kidney. Changes in the concentration of oxygenated (O2Hb) deoxygenated (HHb) and total hemoglobin (THb) were monitored before, during and after renal artery clamping and reperfusion, and the resulting fluctuations in chromophore concentration from baseline used to measure variations in renal perfusion and oxygenation. Results: On clamping the renal artery THb and O2Hb concentrations declined progressively while HHb rose. With reperfusion after releasing the artery clamp O2Hb and THb rose while HHb fell with all parameters returning to its baseline. This pattern was similar in all three trials. Conclusion: This pilot study indicates that a miniaturized NIRS sensor applied directly to the surface of a kidney in an animal model can detect the onset of renal ischemia and tissue hypoxia. With modification, our NIRS-based method may contribute to early detection of renal vascular complications and graft dysfunction following renal transplant.

  5. Improvement of oxygen supply by an artificial carrier in combination with normobaric oxygenation decreases the volume of tissue hypoxia and tissue damage from transient focal cerebral ischemia

    NARCIS (Netherlands)

    Seiffge, David J.; Lapina, Natalia E.; Tsagogiorgas, Charalambos; Theisinger, Bastian; Henning, Robert H.; Schilling, Lothar

    Tissue hypoxia may play an important role in the development of ischemic brain damage. In the present study we investigated in a rat model of transient focal brain ischemia the neuroprotective effects of increasing the blood oxygen transport capacity by applying a semifluorinated alkane

  6. Optoacoustic laser monitoring of cooling and freezing of tissues

    International Nuclear Information System (INIS)

    Larin, Kirill V; Larina, I V; Motamedi, M; Esenaliev, R O

    2002-01-01

    Real-time monitoring of cooling and freezing of tissues, cells, and other biological objects with a high spatial and time resolution, which is necessary for selective destruction of cancer and benign tumours during cryotherapy, as well as for preventing any damage to the structure and functioning of biological objects in cryobiology, is considered. The optoacoustic method, based on the measurement and analysis of acoustic waves induced by short laser pulses, is proposed for monitoring the cooling and freezing of the tissue. The effect of cooling and freezing on the amplitude and time profile of acoustic signals generated in real tissues and in a model object is studied. The experimental results indicate that the optoacoustic laser technique can be used for real-time monitoring of cooling and freezing of biological objects with a submillimeter spatial resolution and a high contrast. (laser biology and medicine)

  7. Even mild respiratory distress alters tissue oxygenation significantly in preterm infants during neonatal transition

    International Nuclear Information System (INIS)

    Schwaberger, Bernhard; Pichler, Gerhard; Binder, Corinna; Pocivalnik, Mirjam; Urlesberger, Berndt; Avian, Alexander

    2014-01-01

    Near-infrared spectroscopy (NIRS) enables continuous non-invasive measurements of regional oxygen saturation (rSO 2 ). The aim was to evaluate the dynamics of rSO 2 of the brain, preductal and postductal tissues during postnatal transition in preterm infants with and without respiratory support (RS). This single-centre study was designed as an exploratory prospective observational study. Fifty one preterm infants (≥ 30 + 0 and < 37 + 0 weeks) delivered by caesarean section were included. RS using a T-Piece-Resuscitator and supplemental oxygen were given according to guidelines. NIRS measurements were carried out by using Invos Monitor (Covidien; USA) for the first 15 min of life. Three NIRS transducers were attached on the forehead (rSO 2 brain), the right forearm (rSO 2 arm) and the left lower leg (rSO 2 leg). Two groups were compared based on need for RS: normal transition (NT) and RS group. Results: In NT group rSO 2 brain increased over time and was significantly higher than rSO 2 arm, whereas in RS group rSO 2 brain and rSO 2 arm increased without significant differences. Courses of rSO 2 arm and rSO 2 leg increased over time and showed a converging pattern with initially lower values of rSO 2 leg in NT group and a diverging pattern with lower levels of rSO 2 leg in RS group. Overall, rSO 2 levels were higher in NT compared to RS group. Conclusion: Our findings indicate that the decreased rSO 2 levels in RS group compared to NT group are not only caused by lower arterial oxygen saturation levels, but also by a compromised perfusion even in infants with only mild respiratory distress. (paper)

  8. Combined effect of protein and oxygen on reactive oxygen and nitrogen species in the plasma treatment of tissue

    Science.gov (United States)

    Gaur, Nishtha; Szili, Endre J.; Oh, Jun-Seok; Hong, Sung-Ha; Michelmore, Andrew; Graves, David B.; Hatta, Akimitsu; Short, Robert D.

    2015-09-01

    The influence of protein and molecular, ground state oxygen (O2) on the plasma generation, and transport of reactive oxygen and nitrogen species (RONS) in tissue are investigated. A tissue target, comprising a 1 mm thick gelatin film (a surrogate for real tissue), is placed on top of a 96-well plate; each well is filled with phosphate buffered saline (PBS, pH 7.4) containing one fluorescent or colorimetric reporter that is specific for one of three RONS (i.e., H2O2, NO2-, or OH•) or a broad spectrum reactive oxygen species reporter (2,7-dichlorodihydrofluorescein). A helium cold atmospheric plasma (CAP) jet contacts the top of the gelatin surface, and the concentrations of RONS generated in PBS are measured on a microplate reader. The data show that H2O2, NO2-, or OH• are generated in PBS underneath the target. Independently, measurements are made of the O2 concentration in the PBS with and without the gelatin target. Adding bovine serum albumin protein to the PBS or gelatin shows that protein either raises or inhibits RONS depending upon the O2 concentration. Our results are discussed in the context of plasma-soft tissue interactions that are important in the development of CAP technology for medicine, biology, and food manufacturing.

  9. 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...

  10. High-spatial-resolution mapping of the oxygen concentration in cortical tissue (Conference Presentation)

    Science.gov (United States)

    Jaswal, Rajeshwer S.; Yaseen, Mohammad A.; Fu, Buyin; Boas, David A.; Sakadžic, Sava

    2016-03-01

    Due to a lack of imaging tools for high-resolution imaging of cortical tissue oxygenation, the detailed maps of the oxygen partial pressure (PO2) around arterioles, venules, and capillaries remain largely unknown. Therefore, we have limited knowledge about the mechanisms that secure sufficient oxygen delivery in microvascular domains during brain activation, and provide some metabolic reserve capacity in diseases that affect either microvascular networks or the regulation of cerebral blood flow (CBF). To address this challenge, we applied a Two-Photon PO2 Microscopy to map PO2 at different depths in mice cortices. Measurements were performed through the cranial window in the anesthetized healthy mice as well as in the mouse models of microvascular dysfunctions. In addition, microvascular morphology was recorded by the two-photon microscopy at the end of each experiment and subsequently segmented. Co-registration of the PO2 measurements and exact microvascular morphology enabled quantification of the tissue PO2 dependence on distance from the arterioles, capillaries, and venules at various depths. Our measurements reveal significant spatial heterogeneity of the cortical tissue PO2 distribution that is dominated by the high oxygenation in periarteriolar spaces. In cases of impaired oxygen delivery due to microvascular dysfunction, significant reduction in tissue oxygenation away from the arterioles was observed. These tissue domains may be the initial sites of cortical injury that can further exacerbate the progression of the disease.

  11. Design, fabrication, and analysis of miniature reflective oxygen monitoring system for use in PDT of esophageal carcinoma

    Science.gov (United States)

    Premasiri, Amaranath; Happawana, Gemunu

    2008-02-01

    Photodynamic therapy (PDT) is an effective and minimally invasive treatment modality with relatively less side effects, which is approved by FDA for the treatment of esophageal cancer. Maximum therapeutic outcome of the PDT protocol for each individual patient requires optimization of the components of PDT operating at their highest efficacy. Tumor necrosis, the method of malignant tissue destruction by PDT, is carried out by the toxic singlet oxygen molecules that are being formed from the molecular oxygen in the tumor. The availability of molecular oxygen, hence being the rate limiting step for PDT plays a key role in the treatment protocol. Currently the PDT of esophageal carcinoma is rather a blind process since there is no method to monitor the tumor oxygen level during the treatment. In this paper we present an optical technique to monitor molecular oxygen level in the PDT milieu. The technique described herein is a reflection oximetry technique designed with small semiconductor lasers and a silicon photodiode. The light used for monitoring system comes from two semiconductor diode lasers of 650 nm and 940 nm wavelengths. The two lasers and the photodiode are mounted onto a small package which is to be imprinted onto a balloon catheter containing the PDT light delivery system. Lasers and the photodiode are powered and controlled by a control box that is connected via a cable. Light sources and the respective photodiode output are controlled by the LabVIEW virtual instrumentation. The sequential on and off light source and the respective reflective signal are processed with MATLAB. The latter code integrates with LabVIEW to make an automatic calculation of the corresponding light absorption by each chromophore and to calculate the change in oxygen level as well as the amount of blood and oxygen present in the treatment area. The designed system is capable of monitoring the change in oxygen level and the blood flow in any part of the human body where the

  12. Monitoring cardiac output during hyperbaric oxygen treatment of haemodynamically unstable patients

    DEFF Research Database (Denmark)

    Hansen, Marco Bo; Treschow, Frederik; Skielboe, Martin

    2013-01-01

    Patients suffering from necrotizing fasciitis (NF) are often haemodynamically unstable and require extended monitoring of cardiovascular parameters; yet this is limited during hyperbaric oxygen treatment (HBOT). We aimed to evaluate the use and safety of transoesophageal Doppler (TED) monitoring ...

  13. Subcutaneous and Intramuscular Hemodynamics and Oxygenation After Cold-Spray Application as Monitored by Near-Infrared Spectroscopy

    Science.gov (United States)

    Shadgan, Babak; Pakravan, Amir H.; Hoens, Alison; Reid, W. Darlene

    2015-01-01

    Context Vapocoolant spray, commonly known as cold spray (CS), is a cryotherapy modality used in sports medicine, athletic training, and rehabilitation settings. Proposed physiologic effects of cryotherapy modalities include reductions in tissue blood flow, oxygenation, and cell metabolism in addition to attenuation of pain perception attributed to reduced superficial nerve conduction velocity. Objective To examine the effects of CS on subcutaneous and intramuscular blood flow and oxygenation on the thigh muscle using near-infrared spectroscopy, an optical method to monitor changes in tissue oxygenated (O2Hb), deoxygenated (HHb), and total (tHb) hemoglobin. Design Cross-sectional study. Setting Muscle Biophysics Laboratory. Patients or Other Participants Participants were 13 healthy adults (8 men, 5 women; age = 37.4 ± 6 years, body mass index = 27.4 ± 2.6, adipose tissue thickness = 7.2 ± 1.8 mm). Intervention(s) Conventional CS was applied to the vastus medialis muscles. Main Outcome Measure(s) Changes in chromophore concentrations of O2Hb, HHb, and tHb at superficial and deep layers were monitored for 5 minutes using a 2-channel near-infrared spectroscopy. Results Thirty seconds after CS application, we observed a decrease from baseline in O2Hb and tHb only in the superficial layer that was maintained for 3 minutes. Conclusions Application of CS induced a transient change in blood flow and oxygenation of the superficial tissues with no change in deeper tissues over the healthy vastus medialis muscle. The limited physiologic effect of CS on the superficial hemodynamics and oxygenation of limb muscles may limit the therapeutic benefit of this cryotherapy modality to a temporary analgesic effect, a hypothesis that warrants a clinical trial on traumatized muscles. PMID:26098273

  14. Effect of oxygen breathing on micro oxygen bubbles in nitrogen-depleted rat adipose tissue at sea level and 25 kPa altitude exposures

    DEFF Research Database (Denmark)

    Randsoe, Thomas; Hyldegaard, Ole

    2012-01-01

    The standard treatment of altitude decompression sickness (aDCS) caused by nitrogen bubble formation is oxygen breathing and recompression. However, micro air bubbles (containing 79% nitrogen), injected into adipose tissue, grow and stabilize at 25 kPa regardless of continued oxygen breathing...... at 101.3 kPa (sea level) or at 25 kPa altitude exposures during continued oxygen breathing. In keeping with previous observations and bubble kinetic models, we hypothesize that oxygen breathing may contribute to oxygen bubble growth at altitude. Anesthetized rats were exposed to 3 h of oxygen...... prebreathing at 101.3 kPa (sea level). Micro oxygen bubbles of 500-800 nl were then injected into the exposed abdominal adipose tissue. The oxygen bubbles were studied for up to 3.5 h during continued oxygen breathing at either 101.3 or 25 kPa ambient pressures. At 101.3 kPa, all bubbles shrank consistently...

  15. Brain tissue partial pressure of oxygen predicts the outcome of severe traumatic brain injury under mild hypothermia treatment

    Directory of Open Access Journals (Sweden)

    Sun H

    2016-08-01

    Full Text Available Hongtao Sun,1,* Maohua Zheng,2,* Yanmin Wang,1 Yunfeng Diao,1 Wanyong Zhao,1 Zhengjun Wei1 1Sixth Department of Neurosurgery, Affiliated Hospital of Logistics University of People’s Armed Police Force, Tianjin, 2Department of Neurosurgery, The First Hospital of Lanzhou University, Lanzhou, People’s Republic of China *These authors contributed equally to this work Objective: The aim of this study was to investigate the clinical significance and changes of brain tissue partial pressure of oxygen (PbtO2 in the course of mild hypothermia treatment (MHT for treating severe traumatic brain injury (sTBI. Methods: There were 68 cases with sTBI undergoing MHT. PbtO2, intracranial pressure (ICP, jugular venous oxygen saturation (SjvO2, and cerebral perfusion pressure (CPP were continuously monitored, and clinical outcomes were evaluated using the Glasgow Outcome Scale score. Results: Of 68 patients with sTBI, PbtO2, SjvO2, and CPP were obviously increased, but decreased ICP level was observed throughout the MHT. PbtO2 and ICP were negatively linearly correlated, while there was a positive linear correlation between PbtO2 and SjvO2. Monitoring CPP and SjvO2 was performed under normal circumstances, and a large proportion of patients were detected with low PbtO2. Decreased PbtO2 was also found after MHT. Conclusion: Continuous PbtO2 monitoring could be introduced to evaluate the condition of regional cerebral oxygen metabolism, thereby guiding the clinical treatment and predicting the outcome. Keywords: severe traumatic brain injury, hypothermia, brain tissue partial pressure of oxygen, therapy

  16. Monitoring Cerebral and Renal Oxygenation Status during Neonatal Digestive Surgeries Using Near Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jonathan Beck

    2017-06-01

    Full Text Available BackgroundDepending on the initial pathology, hypovolemia, intra-abdominal hypertension, and sepsis are often encountered in neonatal digestive surgery. Accurate newborn monitoring during and after surgery is essential to adapt resuscitation protocols. Near infrared spectroscopy (NIRS is non-invasive and can detect hypoperfusion which indicates a low circulatory blood flow, regardless of the cause.ObjectiveEvaluating changes in cerebral and renal regional oxygen saturation during neonatal digestive surgeries, conducted according to normal practices, with commonly used monitoring parameters. Analyzing retrospectively the inter-relationships between NIRS values and mean arterial pressure (MAP values as well as pre-ductal SpO2.MethodsProspective, descriptive, monocentric study. All neonates referred for surgery were included. NIRS allows the measurement of cerebral and renal oxygenation fluctuations, as well as calculating difference in intraoperative and postoperative values.ResultsNineteen patients were included. Cerebral regional oxygen saturation (C rSO2 values were stable while renal regional oxygen saturation (R rSO2 values tended to decrease with time during surgery. Indeed, 72% of rSO2 decline episodes occurred after the first 30 min of surgery, without any significant statistical differences for the next 90 min of surgery. After surgery, the lowest average C and R rSO2 values were evidenced during the first 6 h, with 60% of C rSO2 and R rSO2 anomalies occurring in that time frame. There was no significant statistical difference observed in the following 18 h. There was a significant correlation between R rSO2 and SpO2 values (p < 0.01, but not with C rSO2 values. There was no correlation with the MAP either for the C rSO2 values or R rSO2 ones.ConclusionNIRS is a promising non-invasive bedside tool to monitor cerebral and tissue perfusion, analyzing tissue microcirculation. NIRS has its interest to guide neonatal digestive

  17. Brain tissue partial pressure of oxygen predicts the outcome of severe traumatic brain injury under mild hypothermia treatment.

    Science.gov (United States)

    Sun, Hongtao; Zheng, Maohua; Wang, Yanmin; Diao, Yunfeng; Zhao, Wanyong; Wei, Zhengjun

    2016-01-01

    The aim of this study was to investigate the clinical significance and changes of brain tissue partial pressure of oxygen (PbtO2) in the course of mild hypothermia treatment (MHT) for treating severe traumatic brain injury (sTBI). There were 68 cases with sTBI undergoing MHT. PbtO2, intracranial pressure (ICP), jugular venous oxygen saturation (SjvO2), and cerebral perfusion pressure (CPP) were continuously monitored, and clinical outcomes were evaluated using the Glasgow Outcome Scale score. Of 68 patients with sTBI, PbtO2, SjvO2, and CPP were obviously increased, but decreased ICP level was observed throughout the MHT. PbtO2 and ICP were negatively linearly correlated, while there was a positive linear correlation between PbtO2 and SjvO2. Monitoring CPP and SjvO2 was performed under normal circumstances, and a large proportion of patients were detected with low PbtO2. Decreased PbtO2 was also found after MHT. Continuous PbtO2 monitoring could be introduced to evaluate the condition of regional cerebral oxygen metabolism, thereby guiding the clinical treatment and predicting the outcome.

  18. Monitoring Bone Tissue Engineered (BTE) Constructs Based on the Shifting Metabolism of Differentiating Stem Cells.

    Science.gov (United States)

    Simmons, Aaron D; Sikavitsas, Vassilios I

    2018-01-01

    Ever-increasing demand for bone grafts necessitates the realization of clinical implementation of bone tissue engineered constructs. The predominant hurdle to implementation remains to be securing FDA approval, based on the lack of viable methods for the rigorous monitoring of said constructs. The study presented herein details a method for such monitoring based on the shifting metabolism of mesenchymal stem cells (MSCs) as they differentiate into osteoblasts. To that end, rat MSCs seeded on 85% porous spunbonded poly(L-lactic acid) scaffolds were cultured in flow perfusion bioreactors with baseline or osteoinductive media, and levels of key physio-metabolic markers (oxygen, glucose, osteoprotegerin, and osteocalcin) were monitored throughout culture. Comparison of these non-destructively obtained values and current standard destructive analyses demonstrated key trends useful for the concurrent real-time monitoring of construct cellularity and maturation. Principle among these is the elucidation of the ratio of the rates of oxygen uptake to glucose consumption as a powerful quality marker. This ratio, supported on a physiological basis, has been shown herein to be reliable in the determination of both construct maturation (defined as osteoblastic differentiation and accompanying mineralization) and construct cellularity. Supplementary monitoring of OPG and OCN are shown to provide further validation of such metrics.

  19. The relationship between tumor oxygenation and cell proliferation in human soft tissue sarcomas

    International Nuclear Information System (INIS)

    Nordsmark, Marianne; Hoeyer, Morten; Keller, Johnny; Nielsen, Ole Steen; Jensen, Oluf Myhre; Overgaard, Jens

    1996-01-01

    Purpose: In malignant tumors the oxygenation status and tumor cell proliferation are known to influence local tumor control after radiotherapy. However, the relationship between oxygenation status and tumor cell kinetics in human tumors has not yet been described. Newly developed clinically applicable techniques such as oxygen electrode measurements and assessment of tumor cell proliferation rates have been suggested as promising predictive assays. The purpose of the present study was to characterize tumor oxygenation status in soft tissue sarcomas and to compare this with tumor cell kinetics and clinical parameters. Methods and Materials: Pretreatment tumor oxygenation status was measured by polarographic oxygen needle electrodes and evaluated as the median pO 2 and the percentage of pO 2 values ≤ 5 mmHg and ≤ 2.5 mmHg in 22 patients with primary soft tissue sarcomas. All tumors were characterized by histology, grade of malignancy, the level of microscopic necrosis, the level of effective hemoglobin, and magnetic resonance imaging estimation of tumor volume. The tumor cell potential doubling time and labeling index were measured by flow cytometric and immunohistochemical analysis of tumor biopsy specimens after in vivo incorporation of iododeoxyuridine. Results: There was a significant correlation between the median pO 2 and the tumor cell potential doubling time (p = 0.041), whereas no correlation was found between the level of hypoxia expressed by the percentage of pO 2 values ≤ 2.5 and ≤ 5 mmHg, respectively, and tumor cell potential doubling time. Furthermore, no correlation was found between either of the three tumor oxygenation parameters and labeling index. The material represented large intertumor heterogeneity in oxygenation status, cell kinetics, and tumor volume, and no correlation was found between oxygenation status and either volume, histopathology, grade of malignancy, or effective hemoglobin. Conclusion: This report is the first to suggest

  20. Reaction of oxygen with the respiratory chain in cells and tissues.

    Science.gov (United States)

    Chance, B

    1965-09-01

    This paper considers the way in which the oxygen reaction described by Dr. Nicholls and the ADP control reactions described by Dr. Racker could cooperate to establish a purposeful metabolic control phenomenon in vivo. This has required an examination of the kinetic properties of the respiratory chain with particular reference to methods for determinations of oxygen affinity (K(m)). The constant parameter for tissue respiration is k(1), the velocity constant for the reaction of oxygen with cytochrome oxidase. Not only is this quantity a constant for a particular tissue or mitochondria; it appears to vary little over a wide range of biological material, and for practical purposes a value of 5 x 10(7) at 25 degrees close to our original value (20) is found to apply with adequate accuracy for calculation of K(m) for mammalia. The quantity which will depend upon the tissue and its metabolic state is the value of K(m) itself, and K(m) may be as large as 0.5 microM and may fall to 0.05 microM or less in resting, controlled, or inhibited states. The control characteristic for ADP may depend upon the electron flux due to the cytochrome chain (40); less ADP is required to activate the slower electron transport at lower temperatures than at higher temperatures. The affinity constants for ADP control appear to be less dependent upon substrate supplied to the system. The balance of ADP and oxygen control in vivo is amply demonstrated experimentally and is dependent on the oxygen concentration as follows. In the presence of excess oxygen, control may be due to the ADP or phosphate (or substrate), and the kinetics of oxygen utilization will be independent of the oxygen concentration. As the oxygen concentration is diminished, hemoglobin becomes disoxygenated, deep gradients of oxygen concentration develop in the tissue, and eventually cytochrome oxidase becomes partially and then completely reduced. DPN at this point will become reduced and the electron flow diminished. The rate

  1. 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.

  2. 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.

  3. Microfluidic monitoring of programmed cell death in living plant seed tissue

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Zor, Kinga

    , et al., (2006), BioEssays, 28, p. 1091). Microfluidic cell culture enables in vitro experiments to approach in vivo conditions. Combining microfluidics with the Lab-On-a-Chip concept allows implementing a wide range of assays for real-time monitoring of effects in a biological system of factors...... such as concentration of selected compounds, external pH, oxygen consumption, redox state and cell viability. The aleurone layer of the barley seed is a 2-3 single cell type thick tissue that can be dissected from the embryo and starchy endosperm. During incubation in vitro this mechanically very robust maintains...

  4. Real-Time Monitoring of Singlet Oxygen and Oxygen Partial Pressure During the Deep Photodynamic Therapy In Vitro.

    Science.gov (United States)

    Li, Weitao; Huang, Dong; Zhang, Yan; Liu, Yangyang; Gu, Yueqing; Qian, Zhiyu

    2016-09-01

    Photodynamic therapy (PDT) is an effective noninvasive method for the tumor treatment. The major challenge in current PDT research is how to quantitatively evaluate therapy effects. To our best knowledge, this is the first time to combine multi-parameter detection methods in PDT. More specifically, we have developed a set of system, including the high-sensitivity measurement of singlet oxygen, oxygen partial pressure and fluorescence image. In this paper, the detection ability of the system was validated by the different concentrations of carbon quantum dots. Moreover, the correlation between singlet oxygen and oxygen partial pressure with laser irradiation was observed. Then, the system could detect the signal up to 0.5 cm tissue depth with 660 nm irradiation and 1 cm tissue depth with 980 nm irradiation by using up-conversion nanoparticles during PDT in vitro. Furthermore, we obtained the relationship among concentration of singlet oxygen, oxygen partial pressure and tumor cell viability under certain conditions. The results indicate that the multi-parameter detection system is a promising asset to evaluate the deep tumor therapy during PDT. Moreover, the system might be potentially used for the further study in biology and molecular imaging.

  5. Monitoring of tissue optical properties during thermal coagulation of ex vivo tissues.

    Science.gov (United States)

    Nagarajan, Vivek Krishna; Yu, Bing

    2016-09-01

    Real-time monitoring of tissue status during thermal ablation of tumors is critical to ensure complete destruction of tumor mass, while avoiding tissue charring and excessive damage to normal tissues. Currently, magnetic resonance thermometry (MRT), along with magnetic resonance imaging (MRI), is the most commonly used technique for monitoring and assessing thermal ablation process in soft tissues. MRT/MRI is very expensive, bulky, and often subject to motion artifacts. On the other hand, light propagation within tissue is sensitive to changes in tissue microstructure and physiology which could be used to directly quantify the extent of tissue damage. Furthermore, optical monitoring can be a portable, and cost-effective alternative for monitoring a thermal ablation process. The main objective of this study, is to establish a correlation between changes in tissue optical properties and the status of tissue coagulation/damage during heating of ex vivo tissues. A portable diffuse reflectance spectroscopy system and a side-firing fiber-optic probe were developed to study the absorption (μa (λ)), and reduced scattering coefficients (μ's (λ)) of native and coagulated ex vivo porcine, and chicken breast tissues. In the first experiment, both porcine and chicken breast tissues were heated at discrete temperature points between 24 and 140°C for 2 minutes. Diffuse reflectance spectra (430-630 nm) of native and coagulated tissues were recorded prior to, and post heating. In a second experiment, porcine tissue samples were heated at 70°C and diffuse reflectance spectra were recorded continuously during heating. The μa (λ) and μ's (λ) of the tissues were extracted from the measured diffuse reflectance spectra using an inverse Monte-Carlo model of diffuse reflectance. Tissue heating was stopped when the wavelength-averaged scattering plateaued. The wavelength-averaged optical properties, and , for native porcine tissues (n = 66) at room temperature, were 5.4

  6. 2,3-diphosphoglycerate and oxygen supply of tissues in cardiosurgical diabetics.

    Science.gov (United States)

    Beder, I; Mataseje, A; Kittova, M; Carsky, J; Fischer, V

    2005-01-01

    The oxygen supply of tissues was studied under haemodilution in cardiosurgical diabetic and non-diabetic patients. There were 30 cardiosurgery patients examined, 9 were patients with diabetes mellitus.and 21 were non-diabetic patients. Venous blood samples were examined preoperatively, intraoperatively and for 10 days after operation. Haemodilution caused a decrease in haematocrit values in both groups, as well as in the erythrocyte count and haemoglobin concentration. Postoperatively, an increase was recorded in haematological values in both groups, the values had not reached the baseline even by 10th day. Increased values of blood oxygen saturation and partial oxygen pressure during the operation returned to baseline in both groups in the postoperative days. Values of p50 did not change in both groups for the period of observation. The obtained data suggest that sufficient oxygen supply to tissues was ensured under haemodilution in cardiosurgery patients in both groups. These results confirm multifactorial dependence of blood oxygen transport to tissues (Tab. 1, Fig. 3, Ref. 13).

  7. Development and Validation of Noninvasive Magnetic Resonance Relaxometry for the In Vivo Assessment of Tissue-Engineered Graft Oxygenation.

    Science.gov (United States)

    Einstein, Samuel A; Weegman, Bradley P; Firpo, Meri T; Papas, Klearchos K; Garwood, Michael

    2016-11-01

    Techniques to monitor the oxygen partial pressure (pO 2 ) within implanted tissue-engineered grafts (TEGs) are critically necessary for TEG development, but current methods are invasive and inaccurate. In this study, we developed an accurate and noninvasive technique to monitor TEG pO 2 utilizing proton ( 1 H) or fluorine ( 19 F) magnetic resonance spectroscopy (MRS) relaxometry. The value of the spin-lattice relaxation rate constant (R 1 ) of some biocompatible compounds is sensitive to dissolved oxygen (and temperature), while insensitive to other external factors. Through this physical mechanism, MRS can measure the pO 2 of implanted TEGs. We evaluated six potential MRS pO 2 probes and measured their oxygen and temperature sensitivities and their intrinsic R 1 values at 16.4 T. Acellular TEGs were constructed by emulsifying porcine plasma with perfluoro-15-crown-5-ether, injecting the emulsion into a macroencapsulation device, and cross-linking the plasma with a thrombin solution. A multiparametric calibration equation containing R 1 , pO 2 , and temperature was empirically generated from MRS data and validated with fiber optic (FO) probes in vitro. TEGs were then implanted in a dorsal subcutaneous pocket in a murine model and evaluated with MRS up to 29 days postimplantation. R 1 measurements from the TEGs were converted to pO 2 values using the established calibration equation and these in vivo pO 2 measurements were simultaneously validated with FO probes. Additionally, MRS was used to detect increased pO 2 within implanted TEGs that received supplemental oxygen delivery. Finally, based on a comparison of our MRS data with previously reported data, ultra-high-field (16.4 T) is shown to have an advantage for measuring hypoxia with 19 F MRS. Results from this study show MRS relaxometry to be a precise, accurate, and noninvasive technique to monitor TEG pO 2 in vitro and in vivo.

  8. The effect of PEGT/PBT scaffold architecture on oxygen gradients in tissue engineered cartilaginous constructs

    NARCIS (Netherlands)

    Malda, J.; Woodfield, T.B.F.; van der Vloodt, F.; Kooy, F.K.; Martens, D.E.; Tramper, J.C.; van Blitterswijk, Clemens; Riesle, J.U.

    2004-01-01

    Repair of articular cartilage defects using tissue engineered constructs composed of a scaffold and cultured autologous cells holds promise for future treatments. However, nutrient limitation (e.g. oxygen) has been suggested as a cause of the onset of chondrogenesis solely within the peripheral

  9. Comparison Between Cerebral Tissue Oxygen Tension and Energy Metabolism in Experimental Subdural Hematoma

    DEFF Research Database (Denmark)

    Nielsen, Troels Halfeld; Engell, Susanne I; Johnsen, Rikke Aagaard

    2011-01-01

    BACKGROUND: An experimental swine model (n = 7) simulating an acute subdural hematoma (ASDH) was employed (1) to explore the relation between the brain tissue oxygenation (PbtO(2)) and the regional cerebral energy metabolism as obtained by microdialysis, and (2) to define the lowest level of PbtO(2...

  10. Monitoring and measurement of oxygen concentrations in liquid sodium

    International Nuclear Information System (INIS)

    Smith, D.L.

    1976-01-01

    The measurement of oxygen concentrations in sodium at levels of interest for LMFBR applications is reviewed. Additional data are presented to support the validity of the vanadium-equilibration method as a reference for determination of oxygen concentrations in sodium at levels equal to or less than 15 ppM. Operating experience with electrochemical oxygen meters that have a thoria-yttria electrolyte and a Na--Na 2 O reference electrode is described. Meter lifetimes in excess of one year have generally been achieved for operating temperatures of 352 and 402 0 C, and fairly stable emfs have been observed for periods of several months. 7 fig, 21 references

  11. Point-of-care instrument for monitoring tissue health during skin graft repair

    Science.gov (United States)

    Gurjar, R. S.; Seetamraju, M.; Zhang, J.; Feinberg, S. E.; Wolf, D. E.

    2011-06-01

    We have developed the necessary theoretical framework and the basic instrumental design parameters to enable mapping of subsurface blood dynamics and tissue oxygenation for patients undergoing skin graft procedures. This analysis forms the basis for developing a simple patch geometry, which can be used to map by diffuse optical techniques blood flow velocity and tissue oxygenation as a function of depth in subsurface tissue.skin graft, diffuse correlation analysis, oxygen saturation.

  12. Monitoring of the Adult Patient on Venoarterial Extracorporeal Membrane Oxygenation

    Directory of Open Access Journals (Sweden)

    Mabel Chung

    2014-01-01

    Full Text Available Venoarterial extracorporeal membrane oxygenation (VA ECMO provides mechanical support to the patient with cardiac or cardiopulmonary failure. This paper reviews the physiology of VA ECMO including the determinants of ECMO flow and gas exchange. The efficacy of this therapy may be determined by assessing patient hemodynamics and device flow, overall gas exchange support, markers of adequate oxygen delivery, and pulsatility of the arterial blood pressure waveform.

  13. The Effects of Bougie Diameters on Tissue Oxygen Levels After Sleeve Gastrectomy: A Randomized Experimental Trial

    Directory of Open Access Journals (Sweden)

    Can Konca

    2018-05-01

    Full Text Available Background: Staple-line leak is the most frightening complication of laparoscopic sleeve gastrectomy and several predisposing factors such as using improper staple sizes regardless of gastric wall thickness, narrower bougie diameter and ischemia of the staple line are asserted. Aims: To evaluate the effects of different bougie diameters on tissue oxygen partial pressure at the esophagogastric junction after sleeve gastrectomy. Study Design: A randomized and controlled animal experiment with 1:1:1:1 allocation ratio. Methods: Thirty-two male Wistar Albino rats were randomly divided into 4 groups of 8 each. While 12-Fr bougies were used in groups 1 and 3, 8-Fr bougies were used in groups 2 and 4. Fibrin sealant application was also carried out around the gastrectomy line after sleeve gastrectomy in groups 3 and 4. Burst pressure of gastrectomy line, tissue oxygen partial pressure and hydroxyproline levels at the esophagogastric junction were measured and compared among groups. Results: Mortality was detected in 2 out of 32 rats (6.25% and one of them was in group 2 and the cause of this mortality was gastric leak. Gastric leak was detected in 2 out of 32 rats (6.25%. There was no significant difference in terms of burst pressures, tissue oxygen partial pressure and tissue hydroxyproline levels among the 4 groups. Conclusion: The use of narrower bougie along with fibrin sealant has not had a negative effect on tissue perfusion and wound healing.

  14. Temperature-monitored optical treatment for radial tissue expansion.

    Science.gov (United States)

    Bak, Jinoh; Kang, Hyun Wook

    2017-07-01

    Esophageal stricture occurs in 7-23% of patients with gastroesophageal reflux disease. However, the current treatments including stent therapy, balloon dilation, and bougienage involve limitations such as stent migration, formation of the new strictures, and snowplow effect. The purpose of the current study was to investigate the feasibility of structural expansion in tubular tissue ex vivo during temperature-monitored photothermal treatment with a diffusing applicator for esophageal stricture. Porcine liver was used as an ex vivo tissue sample for the current study. A glass tube was used to maintain a constant distance between the diffuser and tissue surface and to evaluate any variations in the luminal area after 10-W 1470-nm laser irradiation for potential stricture treatment. The 3D goniometer measurements confirmed roughly isotropic distribution with less than 10% deviation from the average angular intensity over 2π (i.e., 0.86 ± 0.09 in arbitrary unit) from the diffusing applicator. The 30-s irradiation increased the tissue temperature up to 72.5 °C, but due to temperature feedback, the interstitial tissue temperature became saturated at 70 °C (i.e., steady-state error = ±0.4 °C). The irradiation times longer than 5 s presented area expansion index of 1.00 ± 0.04, signifying that irreversible tissue denaturation permanently deformed the lumen in a circular shape and secured the equivalent luminal area to that of the glass tube. Application of a temperature feedback controller for photothermal treatment with the diffusing applicator can regulate the degree of thermal denaturation to feasibly treat esophageal stricture in a tubular tissue.

  15. Brain and muscle oxygenation monitoring using near-infrared spectroscopy (NIRS) during all-night sleep

    Science.gov (United States)

    Zhang, Zhongxing; Khatami, Ramin

    2013-03-01

    The hemodynamic changes during natural human sleep are still not well understood. NIRS is ideally suited for monitoring the hemodynamic changes during sleep due to the properties of local measurement, totally safe application and good tolerance to motion. Several studies have been conducted using NIRS in both normal subjects and patients with various sleep disorders during sleep to characterize the hemodynamic changing patterns during different sleep stages and during different symptoms such as obstructive apneas. Here we assessed brain and muscle oxygenation changes in 7 healthy adults during all-night sleep with combined polysomnography measurement to test the notion if hemodynamic changes in sleep are indeed brain specific. We found that muscle and brain showed similar hemodynamic changes during sleep initiation. A decrease in HbO2 and tissue oxygenation index (TOI) while an increase in HHb was observed immediately after sleep onset, and an opposite trend was found after transition with progression to deeper slow-wave sleep (SWS) stage. Spontaneous low frequency oscillations (LFO) and very low frequency oscillations (VLFO) were smaller (Levene's test, psleep (LS) and rapid-eye-movement (REM) sleep in both brain and muscle. Spectral analysis of the NIRS signals measured from brain and muscle also showed reductions in VLFO and LFO powers during SWS with respect to LS and REM sleep. These results indicate a systemic attenuation rather than local cerebral reduction of spontaneous hemodynamic activity in SWS. A systemic physiological mechanism may exist to regulate the hemodynamic changes in brain and muscle during sleep.

  16. A new fibre optic pulse oximeter probe for monitoring splanchnic organ arterial blood oxygen saturation.

    Science.gov (United States)

    Hickey, M; Samuels, N; Randive, N; Langford, R; Kyriacou, P A

    2012-12-01

    A new, continuous method of monitoring splanchnic organ oxygen saturation (SpO(2)) would make the early detection of inadequate tissue oxygenation feasible, reducing the risk of hypoperfusion, severe ischaemia, and, ultimately, death. In an attempt to provide such a device, a new fibre optic based reflectance pulse oximeter probe and processing system were developed followed by an in vivo evaluation of the technology on seventeen patients undergoing elective laparotomy. Photoplethysmographic (PPG) signals of good quality and high signal-to-noise ratio were obtained from the small bowel, large bowel, liver and stomach. Simultaneous peripheral PPG signals from the finger were also obtained for comparison purposes. Analysis of the amplitudes of all acquired PPG signals indicated much larger amplitudes for those signals obtained from splanchnic organs than those obtained from the finger. Estimated SpO(2) values for splanchnic organs showed good agreement with those obtained from the finger fibre optic probe and those obtained from a commercial device. These preliminary results suggest that a miniaturized 'indwelling' fibre optic sensor may be a suitable method for pre-operative and post-operative evaluation of splanchnic organ SpO(2) and their health. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  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. Effect of oxygen and heliox breathing on air bubbles in adipose tissue during 25-kPa altitude exposures

    DEFF Research Database (Denmark)

    Randsoe, T.; Kvist, T.M.; Hyldegaard, O.

    2008-01-01

    and heliox breathing. Preoxygenation enhanced bubble disappearance compared with oxygen and heliox breathing but did not prevent bubble growth. The results indicate that oxygen breathing at 25 kPa promotes air bubble growth in adipose tissue regardless of the tissue nitrogen pressure Udgivelsesdato: 2008/11...

  19. Oxygen regulation of uricase and sucrose synthase synthesis in soybean callus tissue is exerted at the mRNA level

    DEFF Research Database (Denmark)

    Xue, Z T; Larsen, K; Jochimsen, B U

    1991-01-01

    The effect of lowering oxygen concentration on the expression of nodulin genes in soybean callus tissue devoid of the microsymbiont has been examined. Poly(A)+ RNA was isolated from tissue cultivated in 4% oxygen and in normal atmosphere. Quantitative mRNA hybridization experiments using nodule...

  20. Monitor hemoglobin concentration and oxygen saturation in living mouse tail using photoacoustic CT scanner

    Science.gov (United States)

    Liu, Bo; Kruger, Robert; Reinecke, Daniel; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to use PCT spectroscopy scanner to monitor the hemoglobin concentration and oxygen saturation change of living mouse by imaging the artery and veins in a mouse tail. Materials and Methods: One mouse tail was scanned using the PCT small animal scanner at the isosbestic wavelength (796nm) to obtain its hemoglobin concentration. Immediately after the scan, the mouse was euthanized and its blood was extracted from the heart. The true hemoglobin concentration was measured using a co-oximeter. Reconstruction correction algorithm to compensate the acoustic signal loss due to the existence of bone structure in the mouse tail was developed. After the correction, the hemoglobin concentration was calculated from the PCT images and compared with co-oximeter result. Next, one mouse were immobilized in the PCT scanner. Gas with different concentrations of oxygen was given to mouse to change the oxygen saturation. PCT tail vessel spectroscopy scans were performed 15 minutes after the introduction of gas. The oxygen saturation values were then calculated to monitor the oxygen saturation change of mouse. Results: The systematic error for hemoglobin concentration measurement was less than 5% based on preliminary analysis. Same correction technique was used for oxygen saturation calculation. After correction, the oxygen saturation level change matches the oxygen volume ratio change of the introduced gas. Conclusion: This living mouse tail experiment has shown that NIR PCT-spectroscopy can be used to monitor the oxygen saturation status in living small animals.

  1. 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...

  2. Artificial membrane-binding proteins stimulate oxygenation of stem cells during engineering of large cartilage tissue

    Science.gov (United States)

    Armstrong, James P. K.; Shakur, Rameen; Horne, Joseph P.; Dickinson, Sally C.; Armstrong, Craig T.; Lau, Katherine; Kadiwala, Juned; Lowe, Robert; Seddon, Annela; Mann, Stephen; Anderson, J. L. Ross; Perriman, Adam W.; Hollander, Anthony P.

    2015-06-01

    Restricted oxygen diffusion can result in central cell necrosis in engineered tissue, a problem that is exacerbated when engineering large tissue constructs for clinical application. Here we show that pre-treating human mesenchymal stem cells (hMSCs) with synthetic membrane-active myoglobin-polymer-surfactant complexes can provide a reservoir of oxygen capable of alleviating necrosis at the centre of hyaline cartilage. This is achieved through the development of a new cell functionalization methodology based on polymer-surfactant conjugation, which allows the delivery of functional proteins to the hMSC membrane. This new approach circumvents the need for cell surface engineering using protein chimerization or genetic transfection, and we demonstrate that the surface-modified hMSCs retain their ability to proliferate and to undergo multilineage differentiation. The functionalization technology is facile, versatile and non-disruptive, and in addition to tissue oxygenation, it should have far-reaching application in a host of tissue engineering and cell-based therapies.

  3. Noninvasive Intracranial Pressure and Tissue Oxygen Measurements for Space and Earth

    Science.gov (United States)

    Hargens, A. R.; Ballard, R. E.; Murthy, G.; Watenpaugh, D. E.

    1994-01-01

    The paper discusses the following: Increasing intracranial pressure in humans during simulated microgravity. and near-infrared monitoring of model chronic compartment syndrome in exercising skeletal muscle. Compared to upright-seated posture, 0 deg. supine, 6 deg. HDT, and 15 deg. HDT produced TMD changes of 317 +/- 112, 403 +/- 114, and 474 +/- 112 n1 (means +/- S.E.), respectively. Furthermore, postural transitions from 0 deg. supine to 6 deg. HDT and from 6 deg. to 15 deg. HDT generated significant TMD changes (p less than 0.05). There was no hysteresis when postural transitions to HDT were compared to reciprocal transitions toward upright seated posture. Currently, diagnosis of chronic compartment syndrome (CCS) depends on measurement of intramuscular pressure by invasive catheterization. We hypothesized that this syndrome can be detected noninvasively by near-infrared (NIR) spectroscopy, which tracks variations in muscle hemoglobin/myoglobin oxygen saturation. CCS was simulated in the tibialis anterior muscle of 7 male and 3 female subjects by gradual inflation of a cuff placed around the leg to 40 mmHg during 14 minutes of cyclic isokinetic dorsiflexion exercise. On a separate day, subjects underwent the identical exercise protocol with no external compression. In both cases, tissue oxygenation (T(sub O2) was measured in the tibialis anterior by NIR spectroscopy and normalized to a percentage scale between baseline and a T(sub O2) nadir reached during exercise to ischemic exhaustion. Over the course of exercise, T(sub O2) declined at a rate of 1.4 +/- 0.3% per minute with model CCS, yet did not decrease during control exercise. Post-exercise recovery of T(sub O2) was slower with model CCS (2.5 +/- 0.6 min) than in control (1.3 +/- 0.2 min). These results demonstrate that NIR spectroscopy can detect muscle deoxygenation caused by pathologically elevated intramuscular pressure in exercising skeletal muscle. Consequently, this technique shows promise as a

  4. Reliable monitoring of oxygen saturation via pulse oximetry: Which ...

    African Journals Online (AJOL)

    This study focuses on identifying the best site for placement of pulse oximeter probe accurate measuring of oxygen saturation. Twenty-three healthy male volunteers aged 20 to 40 years old were recruited in this study. Cold pressor test was done to stim 460 measurements of SpO2level were obtained throughout the study.

  5. Magnetic field effects on spectrally resolved lifetime of on-line oxygen monitoring using magneto-optic probes

    Science.gov (United States)

    Mermut, O.; Gallant, P.; Le Bouch, N.; Leclair, S.; Noiseux, I.; Vernon, M.; Morin, J.-F.; Diamond, K.; Patterson, M. S.; Samkoe, K.; Pogue, B.

    2009-02-01

    Multimodal agents that serve as both probes for contrast and light-activated effectors of cellular processes in diseased tissue were developed. These agents were introduced into multicellular tumor spheroids (3D tissue models) and in the chorioallantoic membrane (CAM) of a chicken embryo. The luminescence decay was examined using a novel technique involving a spectrally-resolved fluorescence lifetime apparatus integrated with a weak electromagnet. A spectrallyresolved lifetime setup was used to identify magneto-optic species sensitive to magnetic field effects and distinguish from background emissions. We demonstrate that the applied magnetic fields can alter reaction rates and product distribution of some dyes detected by time- and spectrally-resolved luminescence changes. We will discuss the use of exogenous magneto-optical probes taken up in tumors to both induce phototoxicity, a process that is governed by complex and dynamically evolving mechanisms involving reactive oxygen species, and monitor treatment progress. The magnetic field enhancement, measured over a range of weak fields (0-300 mT) is correlated to oxygenation and may be used to monitor dynamic changes occurring due to oxygen consumption over the course of photodynamic therapy. Such online measurements provide the possibility to derive real-time information about response to treatment via monitoring magnetic field enhancement/suppression of the time-resolved, spectrally-resolved luminescence of the probe at the site of the treatment directly. Magnetic perturbation of lifetime can serve as a status reporter, providing optical feedback of oxygen-mediated treatments in situ and allowing for real-time adjustment of a phototherapy treatment plan.

  6. Dissolved oxygen mapping: A powerful tool for site assessments and ground water monitoring

    International Nuclear Information System (INIS)

    Newman, W.A.; Kimball, G.

    1992-01-01

    Dissolved oxygen concentration profiles often provide an excellent indication of the natural biological activity of microorganisms in ground water. The analysis of dissolved oxygen in ground water also provides a rapid, inexpensive method for determining the areal extent of contaminant plumes containing aerobically degraded compounds such as petroleum hydrocarbons. Indigenous hydrocarbon degrading organisms are present at most petroleum product spills giving this technique an almost universal application for dissolved hydrocarbons in ground water. Data from several sites will be presented to demonstrate the relationship between oxygen and dissolved contaminant concentrations. The inverse relationship between oxygen concentrations and dissolved contaminants can be used in many ways. During the initial site assessment, rapid on-site testing of ground water can provide real time data to direct drilling by identification of potentially contaminated locations. Several analytical techniques are available that allow field analysis to be performed in less than five minutes. Dissolved oxygen testing also provides an inexpensive way to monitor hydrocarbon migration without expensive gas chromatography. Often a plume of oxygen depleted ground water extends farther downgradient than the dissolved hydrocarbon plume. The depletion of oxygen in a well can provide an early warning system that detects upgradient contamination before the well is impacted by detectable levels of contaminants. Another application is the measurement of the natural degradation potential for aerobic remediation. If an aerobic in-situ remediation is used, dissolved oxygen monitoring provides an inexpensive method to monitor the progress of the remediation

  7. Blood flow and oxygenation in peritendinous tissue and calf muscle during dynamic exercise in humans

    DEFF Research Database (Denmark)

    Boushel, Robert Christopher; Langberg, H; Green, Sara Marie Ehrenreich

    2000-01-01

    1. Circulation around tendons may act as a shunt for muscle during exercise. The perfusion and oxygenation of Achilles' peritendinous tissue was measured in parallel with that of calf muscle during exercise to determine (1) whether blood flow is restricted in peritendinous tissue during exercise......, and (2) whether blood flow is coupled to oxidative metabolism. 2. Seven individuals performed dynamic plantar flexion from 1 to 9 W. Radial artery and popliteal venous blood were sampled for O2, peritendinous blood flow was determined by 133Xe-washout, calf blood flow by plethysmography, cardiac output...

  8. Localized increase of tissue oxygen tension by magnetic targeted drug delivery

    Science.gov (United States)

    Liong, Celine; Ortiz, Daniel; Ao-ieong, Eilleen; Navati, Mahantesh S.; Friedman, Joel M.; Cabrales, Pedro

    2014-07-01

    Hypoxia is the major hindrance to successful radiation therapy of tumors. Attempts to increase the oxygen (O2) tension (PO2) of tissue by delivering more O2 have been clinically disappointing, largely due to the way O2 is transported and released by the hemoglobin (Hb) within the red blood cells (RBCs). Systemic manipulation of O2 transport increases vascular resistance due to metabolic autoregulation of blood flow to prevent over oxygenation. This study investigates a new technology to increase O2 delivery to a target tissue by decreasing the Hb-O2 affinity of the blood circulating within the targeted tissue. As the Hb-O2 affinity decreases, the tissue PO2 to satisfy tissue O2 metabolic needs increases without increasing O2 delivery or extraction. Paramagnetic nanoparticles (PMNPs), synthetized using gadolinium oxide, were coated with the cell permeable Hb allosteric effector L35 (3,5-trichlorophenylureido-phenoxy-methylpropionic acid). L35 decreases Hb affinity for O2 and favors the release of O2. The L35-coated PMNPs (L35-PMNPs) were intravenously infused (10 mg kg-1) to hamsters instrumented with the dorsal window chamber model. A magnetic field of 3 mT was applied to localize the effects of the L35-PMNPs to the window chamber. Systemic O2 transport characteristics and microvascular tissue oxygenation were measured after administration of L35-PMNPs with and without magnetic field. The tissue PO2 in untreated control animals was 25.2 mmHg. L35-PMNPs without magnetic field decreased tissue PO2 to 23.4 mmHg, increased blood pressure, and reduced blood flow, largely due to systemic modification of Hb-O2 affinity. L35-PMNPs with magnetic field increased tissue PO2 to 27.9 mmHg, without systemic or microhemodynamic changes. These results indicate that localized modification of Hb-O2 affinity can increase PO2 of target tissue without affecting systemic O2 delivery or triggering O2 autoregulation mechanisms. This technology can be used to treat local hypoxia and to

  9. An electrochemical sensor for monitoring oxygen or hydrogen in water

    International Nuclear Information System (INIS)

    Leitai Yang; Morris, D.R.; Lister, D.H.

    1997-01-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ''Nafion'' (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a ∼1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab

  10. An electrochemical sensor for monitoring oxygen or hydrogen in water

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Leitai; Morris, D R; Lister, D H [University of New Brunswick, Fredericton (Canada). Dept. of Chemical Engineering

    1997-02-01

    Preliminary studies have been done on a simple electrochemical sensor which shows promise as a cheap, robust instrument for measuring dissolved oxygen or hydrogen in water. The sensor is based upon the solid-state electrolyte ``Nafion`` (trade name of perfluorinated sulphonic acid, manufactured by DuPont Inc.). The Nafion was dissolved in a mixture of aliphatic alcohols, made into a slurry with platinum black, and applied to a {approx}1 cm-square electrode made of stainless steel gauze. The potential of the electrode was measured relative to a standard calomel electrode (SCE) in acid solutions at room temperature through which mixtures of oxygen and nitrogen or hydrogen and nitrogen were bubbled. The sensor was responsive to the equilibrating gas with good reproducibility. A similar sensor without the Nafion was not at all sensitive to changes in oxygen concentration. The voltage response of the sensor showed non-Nernstian behaviour, which suggests that the electrochemical reactions at the electrode surface are complex. Further testing of the sensor is required to verify its sensitivity and responsiveness in typical reactor coolant chemistries and to demonstrate its durability over a range of temperatures. (author). 4 refs, 4 figs, 1 tab.

  11. A unique mode of tissue oxygenation and the adaptive radiation of teleost fishes.

    Science.gov (United States)

    Randall, D J; Rummer, J L; Wilson, J M; Wang, S; Brauner, C J

    2014-04-15

    Teleost fishes constitute 95% of extant aquatic vertebrates, and we suggest that this is related in part to their unique mode of tissue oxygenation. We propose the following sequence of events in the evolution of their oxygen delivery system. First, loss of plasma-accessible carbonic anhydrase (CA) in the gill and venous circulations slowed the Jacobs-Stewart cycle and the transfer of acid between the plasma and the red blood cells (RBCs). This ameliorated the effects of a generalised acidosis (associated with an increased capacity for burst swimming) on haemoglobin (Hb)-O2 binding. Because RBC pH was uncoupled from plasma pH, the importance of Hb as a buffer was reduced. The decrease in buffering was mediated by a reduction in the number of histidine residues on the Hb molecule and resulted in enhanced coupling of O2 and CO2 transfer through the RBCs. In the absence of plasma CA, nearly all plasma bicarbonate ultimately dehydrated to CO2 occurred via the RBCs, and chloride/bicarbonate exchange was the rate-limiting step in CO2 excretion. This pattern of CO2 excretion across the gills resulted in disequilibrium states for CO2 hydration/dehydration reactions and thus elevated arterial and venous plasma bicarbonate levels. Plasma-accessible CA embedded in arterial endothelia was retained, which eliminated the localized bicarbonate disequilibrium forming CO2 that then moved into the RBCs. Consequently, RBC pH decreased which, in conjunction with pH-sensitive Bohr/Root Hbs, elevated arterial oxygen tensions and thus enhanced tissue oxygenation. Counter-current arrangement of capillaries (retia) at the eye and later the swim bladder evolved along with the gas gland at the swim bladder. Both arrangements enhanced and magnified CO2 and acid production and, therefore, oxygen secretion to those specialised tissues. The evolution of β-adrenergically stimulated RBC Na(+)/H(+) exchange protected gill O2 uptake during stress and further augmented plasma disequilibrium states

  12. Changes in oxygen partial pressure of brain tissue in an animal model of obstructive apnea

    Directory of Open Access Journals (Sweden)

    Torres Marta

    2010-01-01

    Full Text Available Abstract Background Cognitive impairment is one of the main consequences of obstructive sleep apnea (OSA and is usually attributed in part to the oxidative stress caused by intermittent hypoxia in cerebral tissues. The presence of oxygen-reactive species in the brain tissue should be produced by the deoxygenation-reoxygenation cycles which occur at tissue level during recurrent apneic events. However, how changes in arterial blood oxygen saturation (SpO2 during repetitive apneas translate into oxygen partial pressure (PtO2 in brain tissue has not been studied. The objective of this study was to assess whether brain tissue is partially protected from intermittently occurring interruption of O2 supply during recurrent swings in arterial SpO2 in an animal model of OSA. Methods Twenty-four male Sprague-Dawley rats (300-350 g were used. Sixteen rats were anesthetized and non-invasively subjected to recurrent obstructive apneas: 60 apneas/h, 15 s each, for 1 h. A control group of 8 rats was instrumented but not subjected to obstructive apneas. PtO2 in the cerebral cortex was measured using a fast-response oxygen microelectrode. SpO2 was measured by pulse oximetry. The time dependence of arterial SpO2 and brain tissue PtO2 was carried out by Friedman repeated measures ANOVA. Results Arterial SpO2 showed a stable periodic pattern (no significant changes in maximum [95.5 ± 0.5%; m ± SE] and minimum values [83.9 ± 1.3%]. By contrast, brain tissue PtO2 exhibited a different pattern from that of arterial SpO2. The minimum cerebral cortex PtO2 computed during the first apnea (29.6 ± 2.4 mmHg was significantly lower than baseline PtO2 (39.7 ± 2.9 mmHg; p = 0.011. In contrast to SpO2, the minimum and maximum values of PtO2 gradually increased (p 2 were significantly greater relative to baseline and the first apnea dip, respectively. Conclusions These data suggest that the cerebral cortex is partially protected from intermittently occurring interruption of

  13. Carbogen inhalation increases oxygen transport to hypoperfused brain tissue in patients with occlusive carotid artery disease: increased oxygen transport to hypoperfused brain

    DEFF Research Database (Denmark)

    Ashkanian, Mahmoud; Gjedde, Albert; Mouridsen, Kim

    2009-01-01

    to inhaled oxygen (the mixture known as carbogen). In the present study, we measured CBF by positron emission tomography (PET) during inhalation of test gases (O(2), carbogen, and atmospheric air) in healthy volunteers (n = 10) and in patients with occlusive carotid artery disease (n = 6). Statistical...... and Sa(O2) are readily obtained with carbogen, while oxygen increases only Sa(O2). Thus, carbogen improves oxygen transport to brain tissue more efficiently than oxygen alone. Further studies with more subjects are, however, needed to investigate the applicability of carbogen for long-term inhalation...

  14. 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.

  15. 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.

  16. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen.

    Science.gov (United States)

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

    2013-02-01

    Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca(2+) waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus loading with OGB-1/AM and SR101. We report that the occurrence of spontaneous waves is 20 times more frequent in the cerebellar cortex of aging as compared with adult mice, which correlated with a reduction in resting brain oxygen tension. In adult mice, spontaneous glial wave activity increased on reducing resting brain oxygen tension, and ATP-evoked glial waves reduced the tissue O(2) tension. Finally, although spontaneous Purkinje cell (PC) activity was not associated with increased glia wave activity, spontaneous glial waves did affect intracellular Ca(2+) activity in PCs. The increased wave activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology.

  17. CO2 reactivity and brain oxygen pressure monitoring in severe head injury.

    Science.gov (United States)

    Carmona Suazo, J A; Maas, A I; van den Brink, W A; van Santbrink, H; Steyerberg, E W; Avezaat, C J

    2000-09-01

    To investigate the effect of hyperventilation on cerebral oxygenation after severe head injury. A prospective, observational study. Neurointensive care unit at a university hospital. A total of 90 patients with severe head injury (Glasgow Coma Scale score brain tissue oxygen pressure (PbrO2) was performed as a measure of cerebral oxygenation. Arterial PCO2 was decreased each day over a 5-day period for 15 mins by increasing minute volume on the ventilator setting to 20% above baseline. Arterial blood gas analysis was performed before and after changing ventilator settings. Multimodality monitoring, including PbrO2, was performed in all patients. Absolute and relative PbrO2/PaCO2 reactivity was calculated. Outcome at 6 months was evaluated according to the Glasgow Outcome Scale. Effective hyperventilation, defined by a decrease of PaCO2 > or =2 torr (0.27 kPa), was obtained in 218 (84%) of 272 tests performed. Baseline PaCO2 averaged 32.3 +/- 4.5 torr (4.31 +/- 0.60 kPa). Average reduction in PaCO2 was 3.8 +/- 1.7 torr (0.51 +/- 0.23 kPa). PbrO2 decreased by 2.8 +/- 3.7 torr (0.37 +/- 0.49 kPa; p < .001) from a baseline value of 26.5 +/- 11.6 torr (3.53 +/- 1.55 kPa). PbrO2/PaCO2 reactivity was low on day 1 (0.8 +/- 2.3 torr [0.11 +/- 0.31 kPa]), increasing on subsequent days to 6.1 +/- 4.4 torr (0.81 +/- 0.59 kPa) on day 5. PbrO2/PaCO2 reactivity on days 1 and 2 was not related to outcome. In later phases in patients with unfavorable outcome, relative reactivity was increased more markedly, reaching statistical significance on day 5. Increased hyperventilation causes a significant reduction in PbrO2, providing further evidence for possible increased risk of secondary ischemic damage during hyperventilation. The low PbrO2/PaCO2 reactivity on day 1 indicates the decreased responsiveness of cerebral microvascular vessels to PaCO2 changes, caused by generalized vascular narrowing. The increasing PbrO2/PaCO2 reactivity from days 2 to 5 suggests that the risk of

  18. Tissue oxygenation as a target for goal-directed therapy in high-risk surgery : a pilot study

    NARCIS (Netherlands)

    van Beest, Paul A.; Vos, Jaap Jan; Poterman, Marieke; Kalmar, Alain F.; Scheeren, Thomas W. L.

    2014-01-01

    Background:  Tissue hypoperfusion occurs frequently during surgery and may contribute to postoperative organ dysfunction. There is a need for perioperative treatment protocols aiming at improving tissue oxygenation (StO(2)). We hypothesised that intra-operative optimisation of StO(2) improves tissue

  19. Effects of acupuncture on tissue-oxygenation of the rat brain.

    Science.gov (United States)

    Chen, G S; Erdmann, W

    1977-01-01

    Acupuncture has been claimed to be effective in restoring consciousness in some comatose patients. Possible mechanisms to explain alleged acupuncture-induced arousal may include vasodilatory effects caused by sympathetic stimulation which leads to an augmentation of cerebral microcirculation and thereby improves oxygen supply to the brain tissue. Experiments were performed in ten albino rats (Wistar) employing PO2 microelectrodes which were inserted into the cortex of the animals through small burholes. Brain tissue PO2 was continuously recorded before, during, and after acupuncture. Stimulation of certain acupuncture loci (Go-26) resulted in immediate increase of PO2 in the frontal cortex of the rat brain. This effect was reproducible. The effect was comparable to that obtained with increase of inspiratory CO2 known to induce arterial vasodilatation and thus capillary perfusion pressure. The effect was more significant as compared to tissue PO2 increases obtained after increase of inspiratory oxygen concentration from 21% to 100%. It appears that acupuncture causes an increase of brain tissue perfusion which may be, at least in part, responsible for arousal of unconscious patients. Dilatation of cerebral vascular vessels and improvement of autoregulation in the brain by acupuncture stimulation may also explain the effectiveness of acupuncture in the treatment of migraine headache.

  20. Effects of different acute hypoxic regimens on tissue oxygen profiles and metabolic outcomes.

    Science.gov (United States)

    Reinke, Christian; Bevans-Fonti, Shannon; Drager, Luciano F; Shin, Mi-Kyung; Polotsky, Vsevolod Y

    2011-09-01

    Obstructive sleep apnea (OSA) causes intermittent hypoxia (IH) during sleep. Both obesity and OSA are associated with insulin resistance and systemic inflammation, which may be attributable to tissue hypoxia. We hypothesized that a pattern of hypoxic exposure determines both oxygen profiles in peripheral tissues and systemic metabolic outcomes, and that obesity has a modifying effect. Lean and obese C57BL6 mice were exposed to 12 h of intermittent hypoxia 60 times/h (IH60) [inspired O₂ fraction (Fi(O₂)) 21-5%, 60/h], IH 12 times/h (Fi(O₂) 5% for 15 s, 12/h), sustained hypoxia (SH; Fi(O₂) 10%), or normoxia while fasting. Tissue oxygen partial pressure (Pti(O₂)) in liver, skeletal muscle and epididymal fat, plasma leptin, adiponectin, insulin, blood glucose, and adipose tumor necrosis factor-α (TNF-α) were measured. In lean mice, IH60 caused oxygen swings in the liver, whereas fluctuations of Pti(O₂) were attenuated in muscle and abolished in fat. In obese mice, baseline liver Pti(O₂) was lower than in lean mice, whereas muscle and fat Pti(O₂) did not differ. During IH, Pti(O₂) was similar in obese and lean mice. All hypoxic regimens caused insulin resistance. In lean mice, hypoxia significantly increased leptin, especially during SH (44-fold); IH60, but not SH, induced a 2.5- to 3-fold increase in TNF-α secretion by fat. Obesity was associated with striking increases in leptin and TNF-α, which overwhelmed effects of hypoxia. In conclusion, IH60 led to oxygen fluctuations in liver and muscle and steady hypoxia in fat. IH and SH induced insulin resistance, but inflammation was increased only by IH60 in lean mice. Obesity caused severe inflammation, which was not augmented by acute hypoxic regimens.

  1. Effects of variation in cerebral haemodynamics during aneurysm surgery on brain tissue oxygen and metabolism.

    Science.gov (United States)

    Kett-White, R; Hutchinson, P J; Czosnyka, M; al-Rawi, P; Gupta, A; Pickard, J D; Kirkpatrick, P J

    2002-01-01

    This study explores the sensitivities of multiparameter tissue gas sensors and microdialysis to variations in blood pressure, CSF drainage and to well-defined periods of ischaemia accompanying aneurysm surgery, and their predictive value for infarction. A Neurotrend sensor [brain tissue partial pressure of oxygen (PBO2), carbon dioxide (PBCO2), brain pH (pHB) and temperature] and microdialysis catheter were inserted into the appropriate vascular territory prior to craniotomy. Baseline data showed a clear correlation between PBO2 and mean arterial pressure (MAP) below a threshold of 80 mmHg. PBO2 improved with CSF drainage in 20 out of 28 (Wilcoxon: P sensors can be sensitive to acute ischaemia. Microdialysis shows potential in the detection of metabolic changes during tissue hypoxia.

  2. 3D printing of microtube in solid phantom to simulate tissue oxygenation and perfusion (Conference Presentation)

    Science.gov (United States)

    Lv, Xiang; Xue, Yue; Wang, Haili; Shen, Shu Wei; Zhou, Ximing; Liu, Guangli; Dong, Erbao; Xu, Ronald X.

    2017-03-01

    Tissue-simulating phantoms with interior vascular network may facilitate traceable calibration and quantitative validation of many medical optical devices. However, a solid phantom that reliably simulates tissue oxygenation and blood perfusion is still not available. This paper presents a new method to fabricate hollow microtubes for blood vessel simulation in solid phantoms. The fabrication process combines ultraviolet (UV) rapid prototyping technique with fluid mechanics of a coaxial jet flow. Polydimethylsiloxane (PDMS) and a UV-curable polymer are mixed at the designated ratio and extruded through a coaxial needle device to produce a coaxial jet flow. The extruded jet flow is quickly photo-polymerized by ultraviolet (UV) light to form vessel-simulating solid structures at different sizes ranging from 700 μm to 1000 μm. Microtube structures with adequate mechanical properties can be fabricated by adjusting material compositions and illumination intensity. Curved, straight and stretched microtubes can be formed by adjusting the extrusion speed of the materials and the speed of the 3D printing platform. To simulate vascular structures in biologic tissue, we embed vessel-simulating microtubes in a gel wax phantom of 10 cm x10 cm x 5 cm at the depth from 1 to 2 mm. Bloods at different oxygenation and hemoglobin concentration levels are circulated through the microtubes at different flow rates in order to simulate different oxygenation and perfusion conditions. The simulated physiologic parameters are detected by a tissue oximeter and a laser speckle blood flow meter respectively and compared with the actual values. Our experiments demonstrate that the proposed 3D printing process is able to produce solid phantoms with simulated vascular networks for potential applications in medical device calibration and drug delivery studies.

  3. Online monitoring of cartilage tissue in a novel bioreactor

    Science.gov (United States)

    von der Burg, E.; von Buttlar, M.; Grill, W.

    2011-04-01

    Standard techniques for the analysis of biological tissues like immunohistochemical staining are typically invasive and lead to mortification of cells. Non-invasive monitoring is an important element of regenerative medicine because implants and components of implants should be 100% quality-checked with non-invasive and therefore also marker-free methods. We report on a new bioreactor for the production of collagen scaffolds seeded with Mesenchymal Stem Cells (MSCs). It contains a computer controlled mechanical activation and ultrasonic online monitoring and has been constructed for the in situ determination of ultrasonic and rheological parameters. During the cultivation period of about two weeks the scaffold is periodically compressed by two movable pistons for improved differentiation of the MSCs. This periodic compression beneficially ensures the supply with nutrition even inside the sample. During the physiological stimuli, rheological properties are measured by means of highly sensitive load cells. In addition measurements of the speed of sound in the sample and in the culture medium, with frequencies up to 16 MHz, are performed continuously. Therefore piezoceramic transducers are attached to the pistons and emit and detect ultrasonic waves, travelling through the pistons, the sample and the culture medium. The time-of-flight (TOF) of the ultrasonic signals is determined in real time with the aid of chirped excitation and correlation procedures with a resolution of at least 10 ps. The implemented ultrasonic measurement scheme allows beside the speed of sound measurements the detection of the distance between the pistons with a resolution better than 100 nm. The developed monitoring delivers information on rigidity, fluid dynamics and velocity of sound in the sample and in the culture medium. The hermetically sealed bioreactor with its life support system provides a biocompatible environment for MSCs for long time cultivation.

  4. Cutaneous respirometry by dynamic measurement of mitochondrial oxygen tension for monitoring mitochondrial function in vivo.

    Science.gov (United States)

    Harms, Floor A; Voorbeijtel, Wilhelmina J; Bodmer, Sander I A; Raat, Nicolaas J H; Mik, Egbert G

    2013-09-01

    Progress in diagnosis and treatment of mitochondrial dysfunction in chronic and acute disease could greatly benefit from techniques for monitoring of mitochondrial function in vivo. In this study we demonstrate the feasibility of in vivo respirometry in skin. Mitochondrial oxygen measurements by means of oxygen-dependent delayed fluorescence of protoporphyrin IX are shown to provide a robust basis for measurement of local oxygen disappearance rate (ODR). The fundamental principles behind the technology are described, together with an analysis method for retrievel of respirometry data. The feasibility and reproducibility of this clinically useful approach are demonstrated in a series of rats. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Method and apparatus for monitoring oxygen partial pressure in air masks

    Science.gov (United States)

    Kelly, Mark E. (Inventor); Pettit, Donald R. (Inventor)

    2006-01-01

    Method and apparatus are disclosed for monitoring an oxygen partial pressure in an air mask and providing a tactile warning to the user. The oxygen partial pressure in the air mask is detected using an electrochemical sensor, the output signal from which is provided to a comparator. The comparator compares the output signal with a preset reference value or range of values representing acceptable oxygen partial pressures. If the output signal is different than the reference value or outside the range of values, the air mask is vibrated by a vibrating motor to alert the user to a potentially hypoxic condition.

  6. The monitoring of oxygen, hydrogen and carbon in the sodium circuits of the PFR

    International Nuclear Information System (INIS)

    Mason, L.; Morrison, N.S.; Robertson, C.M.; Trevillion, E.A.

    1984-01-01

    The paper reviews the instrumentation available for monitoring oxygen, hydrogen, tritium and carbon impurity levels on the primary and secondary circuits of PFR. Circuit oxygen levels measured using electrochemical oxygen meters are compared to estimates from circuit plugging meters. The data are interpreted in the light of information from cold trap temperatures. Measurements of secondary circuit hydrogen levels using both the sodium and gas phase hydrogen detection equipment are compared to estimates of circuit hydrogen levels from plugging meters and variations in sodium phase hydrogen levels during power operation are discussed. (author)

  7. Differential effects of phenylephrine and norepinephrine on peripheral tissue oxygenation during general anaesthesia : A randomised controlled trial

    NARCIS (Netherlands)

    Poterman, Marieke; Vos, Jaap Jan; Vereecke, Hugo E. M.; Struys, Michel M. R. F.; Vanoverschelde, Henk; Scheeren, Thomas W. L.; Kalmar, Alain F.

    BACKGROUND Phenylephrine and norepinephrine are two vasopressors commonly used to counteract anaesthesia-induced hypotension. Their dissimilar working mechanisms may differentially affect the macro and microcirculation, and ultimately tissue oxygenation. OBJECTIVES We investigated the differential

  8. Development of sensors for monitoring oxygen and free radicals in plant physiology

    Science.gov (United States)

    Chaturvedi, Prachee

    Oxygen plays a critical role in the physiology of photosynthetic organisms, including bioenergetics, metabolism, development, and stress response. Oxygen levels affect photosynthesis, respiration, and alternative oxidase pathways. Likewise, the metabolic rate of spatially distinct plant cells (and therefore oxygen flux) is known to be affected by biotic stress (e.g., herbivory) and environmental stress (e.g., salt/nutrient stress). During aerobic metabolism, cells produce reactive oxygen species (ROS) as a by product. Plants also produce ROS during adaptation to stress (e.g., abscisic acid (ABA) mediated stress responses). If stress conditions are prolonged, ROS levels surpass the capacity of detoxifying mechanisms within the cell, resulting in oxidative damage. While stress response pathways such as ABA-mediated mechanisms have been well characterized (e.g., water stress, inhibited shoot growth, synthesis of storage proteins in seeds), the connection between ROS production, oxygen metabolism and stress response remains unknown. In part, this is because details of oxygen transport at the interface of cell(s) and the surrounding microenvironment remains nebulous. The overall goal of this research was to develop oxygen and Free radical sensors for studying stress signaling in plants. Recent developments in nanomaterials and data acquisition systems were integrated to develop real-time, non-invasive oxygen and Free radical sensors. The availability of these sensors for plant physiologists is an exciting opportunity to probe the functional realm of cells and tissues in ways that were not previously possible.

  9. Oxygen effects on senescence in chondrocytes and mesenchymal stem cells: consequences for tissue engineering.

    Science.gov (United States)

    Moussavi-Harami, Farid; Duwayri, Yazan; Martin, James A; Moussavi-Harami, Farshid; Buckwalter, Joseph A

    2004-01-01

    Primary isolates of chondrocytes and mesenchymal stem cells are often insufficient for cell-based autologous grafting procedures, necessitating in vitro expansion of cell populations. However, the potential for expansion is limited by cellular senescence, a form of irreversible cell cycle arrest regulated by intrinsic and extrinsic factors. Intrinsic mechanisms common to most somatic cells enforce senescence at the so-called "Hayflick limit" of 60 population doublings. Termed "replicative senescence", this mechanism prevents cellular immortalization and suppresses oncogenesis. Although it is possible to overcome the Hayflick limit by genetically modifying cells, such manipulations are regarded as prohibitively dangerous in the context of tissue engineering. On the other hand, senescence associated with extrinsic factors, often called "stress-induced" senescence, can be avoided simply by modifying culture conditions. Because stress-induced senescence is "premature" in the sense that it can halt growth well before the Hayflick limit is reached, growth potential can be significantly enhanced by minimizing culture related stress. Standard culture techniques were originally developed to optimize the growth of fibroblasts but these conditions are inherently stressful to many other cell types. In particular, the 21% oxygen levels used in standard incubators, though well tolerated by fibroblasts, appear to induce oxidative stress in other cells. We reasoned that chondrocytes and MSCs, which are adapted to relatively low oxygen levels in vivo, might be sensitive to this form of stress. To test this hypothesis we compared the growth of MSC and chondrocyte strains in 21% and 5% oxygen. We found that incubation in 21% oxygen significantly attenuated growth and was associated with increased oxidant production. These findings indicated that sub-optimal standard culture conditions sharply limited the expansion of MSC and chondrocyte populations and suggest that cultures for

  10. Optoacoustic monitoring of central and peripheral venous oxygenation during simulated hemorrhage

    Science.gov (United States)

    Petrov, Andrey; Kinsky, Michael; Prough, Donald S.; Petrov, Yuriy; Petrov, Irene Y.; Henkel, S. Nan; Seeton, Roger; Salter, Michael G.; Khan, Muzna N.; Esenaliev, Rinat O.

    2014-03-01

    Circulatory shock may be fatal unless promptly recognized and treated. The most commonly used indicators of shock (hypotension and tachycardia) lack sensitivity and specificity. In the initial stages of shock, the body compensates by reducing blood flow to the peripheral (skin, muscle, etc.) circulation in order to preserve vital organ (brain, heart, liver) perfusion. Characteristically, this can be observed by a greater reduction in peripheral venous oxygenation (for instance, the axillary vein) compared to central venous oxygenation (the internal jugular vein). While invasive measurements of oxygenation are accurate, they lack practicality and are not without complications. We have developed a novel optoacoustic system that noninvasively determines oxygenation in specific veins. In order to test this application, we used lower body negative pressure (LBNP) system, which simulates hemorrhage by exerting a variable amount of suction on the lower body, thereby reducing the volume of blood available for central circulation. Restoration of normal blood flow occurs promptly upon cessation of LBNP. Using two optoacoustic probes, guided by ultrasound imaging, we simultaneously monitored oxygenation in the axillary and internal jugular veins (IJV). LBNP began at -20 mmHg, thereafter was reduced in a step-wise fashion (up to 30 min). The optoacoustically measured axillary oxygenation decreased with LBNP, whereas IJV oxygenation remained relatively constant. These results indicate that our optoacoustic system may provide safe and rapid measurement of peripheral and central venous oxygenation and diagnosis of shock with high specificity and sensitivity.

  11. Metformin Targets Brown Adipose Tissue in vivo and Reduces Oxygen Consumption in vitro

    DEFF Research Database (Denmark)

    Breining, Peter; Jensen, Jonas B; Sundelin, Elias I

    2018-01-01

    basic metabolic rate, making BAT an attractive target for treatment of type 2 diabetes. Under the hypothesis that BAT is a metformin target tissue, we investigated in vivo uptake of [11 C]-metformin tracer in mice and studied in vitro effects of metformin on cultured human brown adipocytes. Injected [11......Metformin is the most widely prescribed oral antidiabetic drug worldwide. Despite well-documented beneficial effects on health outcomes in diabetic patients, the target organs that mediate the effects of metformin remain to be established. In adult humans, brown adipose tissue (BAT) can influence...... uptake. Gene expression profiles of OCTs in BAT revealed ample OCT3 expression in both human and mouse BAT. Incubation of a human brown adipocyte cell models with metformin reduced cellular oxygen consumption in a dose dependent manner. Collectively, these results support BAT as a putative metformin...

  12. Pericellular oxygen monitoring with integrated sensor chips for reproducible cell culture experiments.

    Science.gov (United States)

    Kieninger, J; Aravindalochanan, K; Sandvik, J A; Pettersen, E O; Urban, G A

    2014-04-01

    Here we present an application, in two tumour cell lines, based on the Sensing Cell Culture Flask system as a cell culture monitoring tool for pericellular oxygen sensing. T-47D (human breast cancer) and T98G (human brain cancer) cells were cultured either in atmospheric air or in a glove-box set at 4% oxygen, in both cases with 5% CO2 in the gas phase. Pericellular oxygen tension was measured with the help of an integrated sensor chip comprising oxygen sensor arrays. Obtained results illustrate variation of pericellular oxygen tension in attached cells covered by stagnant medium. Independent of incubation conditions, low pericellular oxygen concentration levels, usually associated with hypoxia, were found in dense cell cultures. Respiration alone brought pericellular oxygen concentration down to levels which could activate hypoxia-sensing regulatory processes in cultures believed to be aerobic. Cells in culture believed to experience conditions of mild hypoxia may, in reality, experience severe hypoxia. This would lead to incorrect assumptions and suggests that pericellular oxygen concentration readings are of great importance to obtain reproducible results when dealing with hypoxic and normoxic (aerobic) incubation conditions. The Sensing Cell Culture Flask system allows continuous monitoring of pericellular oxygen concentration with outstanding long-term stability and no need for recalibration during cell culture experiments. The sensor is integrated into the flask bottom, thus in direct contact with attached cells. No additional equipment needs to be inserted into the flask during culturing. Transparency of the electrochemical sensor chip allows optical inspection of cells attached on top of the sensor. © 2014 John Wiley & Sons Ltd.

  13. Stable hydrogen, oxygen and sulfur isotopes composition in different tissues of cattle

    International Nuclear Information System (INIS)

    Sun Fengmei; Shi Guangyu; Wang Huiwen; Yang Shuming

    2012-01-01

    In order to research on stable hydrogen, oxygen, sulfur isotopes composition in different tissues of cattle, as well as the breed, δ 2 H and δ 34 S values of different defatted muscle, cattle tail hair, blood, liver, also δ 2h and δ 18 O values of water from muscle were determined by isotope ratio mass spectrometry. The stable sulfur isotope composition was not affected by cattle variety, meanwhile the hydrogen was uncertain; the δ 2 H and δ 34 S values between different defatted muscle, blood, liver, cattle hair were significantly different, at the same time the δ 34 S and δ 2 H values between each tissue were not significantly correlated; the δ 2 H values were strongly correlated with the δ 18 O values of muscle water. The above results indicated that stable sulfur and hydrogen isotopes fractionation in the various tissues were discrepant, thus the proper tissue should be selected according to the purpose and object in the beef traceability. (authors)

  14. Investigation of endocrine and immunological response in fat tissue to hyperbaric oxygen administration in rats.

    Science.gov (United States)

    Şen, H; Erbağ, G; Ovali, M A; Öztopuz, R Ö; Uzun, M

    2016-04-30

    Though HBO treatment is becoming more common, the mechanism of action is not fully known. The positive effects of HBO administration on the inflammatory response is thought to be a possible basic mechanism. As a result, we aimed to research whether endocrine and immunological response of fat tissue changes in rats given HBO treatment model. This research was carried out on Wistar albino rats, they were treated with hyperbaric oxygen therapy. Their fatty tissue were taken from the abdomen, gene expression of the cytokines and adipokines were analyzed with Real time PCR method. When the gene expression of hormones and cytokines by fat tissue was examined, the leptin, visfatin, TNF-α, IL-1β and IL-10 levels in the HBO treatment group were statistically significantly increased compared to the control group (p=0.0313, p=0.0156, p=0.0156, p=0.0156, p=0.0313). In conclusion, in our study we identified that HBO administration affected the endochrinological functions of fat tissue.

  15. Nanoparticle-enhanced spectral photoacoustic tomography: effect of oxygen saturation and tissue heterogeneity

    Science.gov (United States)

    Vogt, William C.; Jia, Congxian; Wear, Keith A.; Garra, Brian S.; Pfefer, T. Joshua

    2016-03-01

    Molecular imaging for breast cancer detection, infectious disease diagnostics and preclinical animal research may be achievable through combined use of targeted exogenous agents - such as nanoparticles - and spectral Photoacoustic Tomography (PAT). However, tissue heterogeneity can alter fluence distributions and acoustic propagation, corrupting measured PAT absorption spectra and complicating in vivo nanoparticle detection and quantitation. Highly absorptive vascular structures represent a common confounding factor, and variations in vessel hemoglobin saturation (SO2) may alter spectral content of signals from adjacent/deeper regions. To evaluate the impact of this effect on PAT nanoparticle detectability, we constructed heterogeneous phantoms with well-characterized channel-inclusion geometries and biologically relevant optical and acoustic properties. Phantoms contained an array of tubes at several depths filled with hemoglobin solutions doped with varying concentrations of gold nanorods with an absorption peak at 780 nm. Both overlying and target network SO2 was tuned using sodium dithionite. Phantoms were imaged from 700 to 900 nm using a custom PAT system comprised of a tunable pulsed laser and a research-grade ultrasound system. Recovered nanoparticle spectra were analyzed and compared with results from both spectrophotometry and PAT data from waterimmersed tubes containing blood and nanoparticle solutions. Results suggested that nanoparticle selection for a given PAT application should take into account expected oxygenation states of both target blood vessel and background tissue oxygenation to achieve optimal performance.

  16. Polydeoxyribonucleotide Improves Peripheral Tissue Oxygenation and Accelerates Angiogenesis in Diabetic Foot Ulcers

    Directory of Open Access Journals (Sweden)

    Seoyoung Kim

    2017-11-01

    Full Text Available Background Polydeoxyribonucleotide (PDRN is known to have anti-inflammatory and angiogenic effects and to accelerate wound healing. The aim of this study was to investigate whether PDRN could improve peripheral tissue oxygenation and angiogenesis in diabetic foot ulcers. Methods This was a prospective randomized controlled clinical trial. Twenty patients with a non-healing diabetic foot ulcer were randomly distributed into a control group (n=10 and a PDRN group (n=10. Initial surgical debridement and secondary surgical procedures such as a split-thickness skin graft, primary closure, or local flap were performed. Between the initial surgical debridement and secondary surgical procedures, 0.9% normal saline (3 mL or PDRN was injected for 2 weeks by the intramuscular (1 ampule, 3 mL, 5.625 mg, 5 days per week and perilesional routes (1 ampule, 3 mL, 5.625 mg, 2 days per week. Transcutaneous oxygen tension (TcPO2 was evaluated using the Periflux System 5000 with TcPO2/CO2 unit 5040 before the injections and on days 1, 3, 7, 14, and 28 after the start of the injections. A pathologic review (hematoxylin and eosin stain of the debrided specimens was conducted by a pathologist, and vessel density (average number of vessels per visual field was calculated. Results Compared with the control group, the PDRN-treated group showed improvements in peripheral tissue oxygenation on day 7 (P<0.01, day 14 (P<0.001, and day 28 (P<0.001. The pathologic review of the specimens from the PDRN group showed increased angiogenesis and improved inflammation compared with the control group. No statistically significant difference was found between the control group and the PDRN group in terms of vessel density (P=0.094. Complete healing was achieved in every patient. Conclusions In this study, PDRN improved peripheral tissue oxygenation. Moreover, PDRN is thought to be effective in improving inflammation and angiogenesis in diabetic foot ulcers.

  17. Tissue viability monitoring: a multi-sensor wearable platform approach

    Science.gov (United States)

    Mathur, Neha; Davidson, Alan; Buis, Arjan; Glesk, Ivan

    2016-12-01

    Health services worldwide are seeking ways to improve patient care for amputees suffering from diabetes, and at the same time reduce costs. The monitoring of residual limb temperature, interface pressure and gait can be a useful indicator of tissue viability in lower limb amputees especially to predict the occurrence of pressure ulcers. This is further exacerbated by elevated temperatures and humid micro environment within the prosthesis which encourages the growth of bacteria and skin breakdown. Wearable systems for prosthetic users have to be designed such that the sensors are minimally obtrusive and reliable enough to faithfully record movement and physiological signals. A mobile sensor platform has been developed for use with the lower limb prosthetic users. This system uses an Arduino board that includes sensors for temperature, gait, orientation and pressure measurements. The platform transmits sensor data to a central health authority database server infrastructure through the Bluetooth protocol at a suitable sampling rate. The data-sets recorded using these systems are then processed using machine learning algorithms to extract clinically relevant information from the data. Where a sensor threshold is reached a warning signal can be sent wirelessly together with the relevant data to the patient and appropriate medical personnel. This knowledge is also useful in establishing biomarkers related to a possible deterioration in a patient's health or for assessing the impact of clinical interventions.

  18. The concentration of oxygen dissolved in tissues at the time of irradiation as a factor in radiotherapy

    International Nuclear Information System (INIS)

    Gray, L.H.; Conger, A.D.; Ebert, M.; Hornsey, S.; Scott, O.C.A.

    1984-01-01

    The sensitivity of tumour cells to X rays has been shown to be about three times as great when irradiated in a well-oxygenated medium as under anoxic conditions. The manner in which sensitivity depends on oxygen tension closely resembles that found by other workers for plant and insect tissues. The sensitivity of the tumour cells to fast neutron radiation is only slightly affected by oxygen tension. Consideration is given to the supply of oxygen to tissues as a factor in radiotherapy, and it is concluded on the basis of existing knowledge that in certain circumstances the effectiveness of X-ray treatment might be increased if the patient were breathing oxygen at the time of irradiation

  19. Prognostic value of changes in brain tissue oxygen pressure before and after decompressive craniectomy following severe traumatic brain injury.

    Science.gov (United States)

    Lubillo, Santiago T; Parrilla, Dácil M; Blanco, José; Morera, Jesús; Dominguez, Jaime; Belmonte, Felipe; López, Patricia; Molina, Ismael; Ruiz, Candelaria; Clemente, Francisco J; Godoy, Daniel A

    2018-05-01

    OBJECTIVE In severe traumatic brain injury (TBI), the effects of decompressive craniectomy (DC) on brain tissue oxygen pressure (PbtO 2 ) and outcome are unclear. The authors aimed to investigate whether changes in PbtO 2 after DC could be used as an independent prognostic factor. METHODS The authors conducted a retrospective, observational study at 2 university hospital ICUs. The study included 42 patients who were admitted with isolated moderate or severe TBI and underwent intracranial pressure (ICP) and PbtO 2 monitoring before and after DC. The indication for DC was an ICP higher than 25 mm Hg refractory to first-tier medical treatment. Patients who underwent primary DC for mass lesion evacuation were excluded. However, patients were included who had undergone previous surgery as long as it was not a craniectomy. ICP/PbtO 2 monitoring probes were located in an apparently normal area of the most damaged hemisphere based on cranial CT scanning findings. PbtO 2 values were routinely recorded hourly before and after DC, but for comparisons the authors used the first PbtO 2 value on ICU admission and the number of hours with PbtO 2 areas under the curve for the mean PbtO 2 values at 12 and 24 hours after DC were 0.878 (95% CI 0.75-1, p areas of the most damaged hemisphere, have independent prognostic value for the 6-month outcome in TBI patients.

  20. Integrated fiber optical and thermal sensor for noninvasive monitoring of blood and human tissue

    Science.gov (United States)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schiffner, Gerhard

    2007-05-01

    A novel concept of noninvasive monitoring of human tissue and blood based on optical diffuse reflective spectroscopy combined with metabolic heat measurements has been under development. A compact integrated fiber optical and thermal sensor has been developed. The idea of the method was to evaluate by optical spectroscopy haemoglobin and derivative concentrations and supplement with data associated with the oxidative metabolism of glucose. Body heat generated by glucose oxidation is based on the balance of capillary glucose and oxygen supply to the cells. The variation in glucose concentration is followed also by a difference from a distance (or depth) of scattered through the body radiation. So, blood glucose can be estimated by measuring the body heat and the oxygen supply. The sensor pickup contains of halogen lamp and LEDs combined with fiber optical bundle to deliver optical radiation inside and through the patient body, optical and thermal detectors. Fiber optical probe allows diffuse scattering measurement down to a depth of 2.5 mm in the skin including vascular system, which contributes to the control of the body temperature. The sensor pickup measures thermal generation, heat balance, blood flow rate, haemoglobin and derivative concentrations, environmental conditions. Multivariate statistical analysis was applied to convert various signals from the sensor pickup into physicochemical variables. By comparing the values from the noninvasive measurement with the venous plasma result, analytical functions for patient were obtained. Cluster analysis of patient groups was used to simplify a calibration procedure. Clinical testing of developed sensor is being performed.

  1. Validation of NIRS in measuring tissue hemoglobin concentration and oxygen saturation on ex vivo and isolated limb models

    Science.gov (United States)

    Xu, Xiaorong; Zhu, Wen; Padival, Vikram; Xia, Mengna; Cheng, Xuefeng; Bush, Robin; Christenson, Linda; Chan, Tim; Doherty, Tim; Iatridis, Angelo

    2003-07-01

    Photonify"s tissue spectrometer uses Near-Infrared Spectroscopy for real-time, noninvasive measurement of hemoglobin concentration and oxygen saturation [SO2] of biological tissues. The technology was validated by a series of ex vivo and animal studies. In the ex vivo experiment, a close loop blood circulation system was built, precisely controlling the oxygen saturation and the hemoglobin concentration of a liquid phantom. Photonify"s tissue spectrometer was placed on the surface of the liquid phantom for real time measurement and compared with a gas analyzer, considered the gold standard to measure oxygen saturation and hemoglobin concentration. In the animal experiment, the right hind limb of each dog accepted onto the study was surgically removed. The limb was kept viable by connecting the femoral vein and artery to a blood-primed extracorporeal circuit. Different concentrations of hemoglobin were obtained by adding designated amount of saline solution into the perfusion circuit. Photonify"s tissue spectrometers measured oxygen saturation and hemoglobin concentration at various locations on the limb and compared with gas analyzer results. The test results demonstrated that Photonify"s tissue spectrometers were able to detect the relative changes in tissue oxygen saturation and hemoglobin concentration with a high linear correlation compared to the gas analyzer

  2. Acetazolamide during acute hypoxia improves tissue oxygenation in the human brain.

    Science.gov (United States)

    Wang, Kang; Smith, Zachary M; Buxton, Richard B; Swenson, Erik R; Dubowitz, David J

    2015-12-15

    Low doses of the carbonic anhydrase inhibitor acetazolamide provides accelerated acclimatization to high-altitude hypoxia and prevention of cerebral and other symptoms of acute mountain sickness. We previously observed increases in cerebral O2 metabolism (CMRO2 ) during hypoxia. In this study, we investigate whether low-dose oral acetazolamide (250 mg) reduces this elevated CMRO2 and in turn might improve cerebral tissue oxygenation (PtiO2 ) during acute hypoxia. Six normal human subjects were exposed to 6 h of normobaric hypoxia with and without acetazolamide prophylaxis. We determined CMRO2 and cerebral PtiO2 from MRI measurements of cerebral blood flow (CBF) and cerebral venous O2 saturation. During normoxia, low-dose acetazolamide resulted in no significant change in CBF, CMRO2 , or PtiO2 . During hypoxia, we observed increases in CBF [48.5 (SD 12.4) (normoxia) to 65.5 (20.4) ml·100 ml(-1)·min(-1) (hypoxia), P effect was improved cerebral tissue PtiO2 during acute hypoxia [11.4 (2.7) (hypoxia) to 16.5 (3.0) mmHg (hypoxia + acetazolamide), P effect, low-dose acetazolamide is effective at the capillary endothelium, and we hypothesize that local interruption in cerebral CO2 excretion accounts for the improvements in CMRO2 and ultimately in cerebral tissue oxygenation during hypoxia. This study suggests a potentially pivotal role of cerebral CO2 and pH in modulating CMRO2 and PtiO2 during acute hypoxia. Copyright © 2015 the American Physiological Society.

  3. Determination of optical properties, drug concentration, and tissue oxygenation in human pleural tissue before and after Photofrin-mediated photodynamic therapy

    Science.gov (United States)

    Ong, Yi Hong; Padawer-Curry, Jonah; Finlay, Jarod C.; Kim, Michele M.; Dimofte, Andreea; Cengel, Keith; Zhu, Timothy C.

    2018-02-01

    PDT efficacy depends on the concentration of photosensitizer, oxygen, and light delivery in patient tissues. In this study, we measure the in-vivo distribution of important dosimetric parameters, namely the tissue optical properties (absorption μa (λ) and scattering μs ' (λ) coefficients), photofrin concentration (cphotofrin), blood oxygen saturation (%StO2), and total hemoglobin concentration (THC), before and after PDT. We characterize the inter- and intra-patient heterogeneity of these quantities and explore how these properties change as a result of PDT treatment. The result suggests the need for real-time dosimetry during PDT to optimize the treatment condition depending on the optical and physiological properties.

  4. [The effect of prophylactically administered n-acetylcysteine on clinical indicators for tissue oxygenation during hyperoxic ventilation in cardiac risk patients].

    Science.gov (United States)

    Spies, C; Giese, C; Meier-Hellmann, A; Specht, M; Hannemann, L; Schaffartzik, W; Reinhart, K

    1996-04-01

    Hyperoxic ventilation, used to prevent hypoxia during potential periods of hypoventilation, has been reported to paradoxically decrease whole-body oxygen consumption (VO2). Reduction in nutritive blood flow due to oxygen radical production is one possible mechanism. We investigated whether pretreatment with the sulfhydryl group donor and O2 radical scavenger N-acetylcysteine (NAC) would preserve VO2 and other clinical indicators of tissue oxygenation in cardiac risk patients. Thirty patients, requiring hemodynamic monitoring (radial and pulmonary artery catheters) because of cardiac risk factors, were included in this randomized investigation. All patients exhibited stable clinical conditions (hemodynamics, body temperature, hemoglobin, F1O2 depression ( > 0.2 mV) was significantly less marked in the NAC group (NAC: -0.02 +/- 0.17 vs placebo: -0.23 +/- 0.15; P depression if patients were prophylactically treated with NAC. This suggests that pretreatment with NAC could be considered to attenuate impaired tissue oxygenation and to preserve myocardial performance better in cardiac risk patients during hyperoxia.

  5. Research progress of on-line automatic monitoring of chemical oxygen demand (COD) of water

    Science.gov (United States)

    Cai, Youfa; Fu, Xing; Gao, Xiaolu; Li, Lianyin

    2018-02-01

    With the increasingly stricter control of pollutant emission in China, the on-line automatic monitoring of water quality is particularly urgent. The chemical oxygen demand (COD) is a comprehensive index to measure the contamination caused by organic matters, and thus it is taken as one important index of energy-saving and emission reduction in China’s “Twelve-Five” program. So far, the COD on-line automatic monitoring instrument has played an important role in the field of sewage monitoring. This paper reviews the existing methods to achieve on-line automatic monitoring of COD, and on the basis, points out the future trend of the COD on-line automatic monitoring instruments.

  6. 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.

  7. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation.

    Science.gov (United States)

    Polf, Jerimy C; Panthi, Rajesh; Mackin, Dennis S; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T; Beddar, Sam

    2013-09-07

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from (12)C (4.44 MeV) and (16)O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 10(7) oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from (16)O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring (16)O PG emission.

  8. Changes in muscle tissue oxygenation during stagnant ischemia in septic patients.

    Science.gov (United States)

    Pareznik, Roman; Knezevic, Rajko; Voga, Gorazd; Podbregar, Matej

    2006-01-01

    To determine changes in the rate of thenar muscles tissue deoxygenation during stagnant ischemia in patients with severe sepsis and septic shock. Prospective observational study in the medical ICU of a general hospital. Consecutive patients admitted to ICU with septic shock (n=6), severe sepsis (n=6), localized infection (n=3), and healthy volunteers (n=15). Upper limb ischemia was induced by rapid automatic pneumatic cuff inflation around upper arm. Thenar muscle tissue oxygen saturation (StO2) was measured continuously by near-infrared spectroscopy before and during upper limb ischemia. StO(2) before intervention was comparable in patients with septic shock, severe sepsis, or localized infection and healthy volunteers (89 [65, 92]% vs. 82 [72, 91]% vs. 87 [85, 92]% vs. 83 [79, 93]%, respectively; p>0.1). The rate of StO(2) decrease during stagnant ischemia after initial hemodynamic stabilization was slower in septic shock patients than in those with severe sepsis or localized infection and in controls (-7.0 [-3.6, -11.0] %/min vs. -10.4 [-7.8, -13.3] %/min vs. -19.5 [-12.3, -23.3] vs. -37.4 [-27.3, -56.2] %/min, respectively; p=0.041). At ICU discharge the rate of StO2 decrease did not differ between the septic shock, severe sepsis, and localized infection groups (-17.0 [-9.3, -28.9] %/min vs. -19.9 [-13.3, -23.6] %/min vs. -23.1 [-20.7, -26.2] %/min, respectively), but remained slower than in controls (p<0.01). The rate of StO2 decrease was correlated with Sequential Organ Failure Assessment (SOFA) score (r=0.739, p<0.001). After hemodynamic stabilization thenar muscle tissue oxygen saturation during stagnant ischemia decreases slower in septic shock patients than in patients with severe sepsis or localized infection and in healthy volunteers. During ICU stay and improvement of sepsis the muscle tissue deoxygenation rate increases in survivors of both septic shock and severe sepsis and was correlated with SOFA score.

  9. Oscillation of tissue oxygen index in non-exercising muscle during exercise.

    Science.gov (United States)

    Yano, T; Afroundeh, R; Shirakawa, K; Lian, C-S; Shibata, K; Xiao, Z; Yunoki, T

    2015-09-01

    The purpose of the present study was to examine how oscillation of tissue oxygen index (TOI) in non-exercising exercise is affected during high-intensity and low-intensity exercises. Three exercises were performed with exercise intensities of 30% and 70% peak oxygen uptake (Vo(2)peak) for 12 min and with exercise intensity of 70% Vo(2)peak for 30 s. TOI in non-exercising muscle (biceps brachii) during the exercises for 12 min was determined by nearinfrared spectroscopy. TOI in the non-exercising muscle during the exercises was analyzed by fast Fourier transform (FFT) to obtain power spectra density (PSD). The frequency at which maximal PSD appeared (Fmax) during the exercise with 70% Vo(2)peak for 12 min (0.00477 ± 0.00172 Hz) was significantly lower than that during the exercise with 30% Vo2peak for 12 min (0.00781 ± 0.00338 Hz). There were significant differences in blood pH and blood lactate between the exercise with 70% Vo(2)peak and the exercise with 30% Vo(2)peak. It is concluded that TOI in nonexercising muscle oscillates during low-intensity exercise as well as during high-intensity exercise and that the difference in Fmax between the two exercises is associated with the difference in increase in blood lactate derived from the exercise.

  10. A pilot study of a new spectrophotometry device to measure tissue oxygen saturation.

    Science.gov (United States)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-09-01

    Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C.Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland-Altman method was used to assess agreement between them.The devices showed agreement in overall tracking of changes in SO2. Test-retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range.Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative.

  11. A pilot study of a new spectrophotometry device to measure tissue oxygen saturation

    International Nuclear Information System (INIS)

    Abel, Gemma; Allen, John; Drinnan, Michael

    2014-01-01

    Tissue oxygen saturation (SO2) measurements have the potential for far wider use than at present but are limited by device availability and portability for many potential applications. A device based on a small, low-cost general-purpose spectrophotometer (the Harrison device) might facilitate wider use. The aim of this study was to compare the Harrison device with a commercial instrument, the LEA O2C. Measurements were carried out on the forearm and finger of 20 healthy volunteers, using a blood pressure cuff on the upper arm to induce different levels of oxygenation. Repeatability of both devices was assessed, and the Bland–Altman method was used to assess agreement between them. The devices showed agreement in overall tracking of changes in SO2. Test–retest agreement for the Harrison device was worse than for O2C, with SD repeatability of 10.6% (forearm) or 18.6% (finger). There was no overall bias between devices, but mean (SD) difference of 1.2 (11.8%) (forearm) or 4.4 (11.5%) (finger) were outside of a clinically acceptable range. Disagreements were attributed to the stability of the Harrison probe and the natural SO2 variations across the skin surface increasing the random error. Therefore, though not equivalent to the LEA O2C, a probe redesign and averaged measurements may help establish the Harrison device as a low cost alternative. (paper)

  12. Noninvasive Optical Monitoring of Spinal Cord Hemodynamics and Oxygenation after Acute Spinal Cord Injury

    Science.gov (United States)

    2017-09-01

    model in anesthetized (immobile) animals. Task 1: Evaluating the NIRS system function in a pig model of SCI in conjunction with IP measurements...started. We are collecting spinal cord NIRS data, using the V1 and OXT5 NIRS systems, in conjunction with IP measurements of spinal cord tissue...model of SCI in conjunction with IP measurements of oxygen, perfusion, pressure, and metabolism. SC150178 Kwon - Anual Report – Sep 01 2016 – Aug 31

  13. Diet-induced weight loss decreases adipose tissue oxygen tension with parallel changes in adipose tissue phenotype and insulin sensitivity in overweight humans

    NARCIS (Netherlands)

    Vink, R.G.; Roumans, N.J.; Čajlaković, M.; Cleutjens, J.P.M.; Boekschoten, M.V.; Fazelzadeh, P.; Vogel, M.A.A.; Blaak, E.E.; Mariman, E.C.; Baak, van M.A.; Goossens, G.H.

    2017-01-01

    Background/objectives: Although adipose tissue (AT) hypoxia is present in rodent models of obesity, evidence for this in humans is limited. Here, we investigated the effects of diet-induced weight loss (WL) on abdominal subcutaneous AT oxygen tension (pO 2), AT blood flow (ATBF), AT capillary

  14. Real-Time Molecular Monitoring of Chemical Environment in ObligateAnaerobes during Oxygen Adaptive Response

    Energy Technology Data Exchange (ETDEWEB)

    Holman, Hoi-Ying N.; Wozei, Eleanor; Lin, Zhang; Comolli, Luis R.; Ball, David. A.; Borglin, Sharon; Fields, Matthew W.; Hazen, Terry C.; Downing, Kenneth H.

    2009-02-25

    Determining the transient chemical properties of the intracellular environment canelucidate the paths through which a biological system adapts to changes in its environment, for example, the mechanisms which enable some obligate anaerobic bacteria to survive a sudden exposure to oxygen. Here we used high-resolution Fourier Transform Infrared (FTIR) spectromicroscopy to continuously follow cellular chemistry within living obligate anaerobes by monitoring hydrogen bonding in their cellular water. We observed a sequence of wellorchestrated molecular events that correspond to changes in cellular processes in those cells that survive, but only accumulation of radicals in those that do not. We thereby can interpret the adaptive response in terms of transient intracellular chemistry and link it to oxygen stress and survival. This ability to monitor chemical changes at the molecular level can yield important insights into a wide range of adaptive responses.

  15. Effect of oxygen breathing and perfluorocarbon emulsion treatment on air bubbles in adipose tissue during decompression sickness

    DEFF Research Database (Denmark)

    Randsoe, T; Hyldegaard, O

    2009-01-01

    Decompression sickness (DCS) after air diving has been treated with success by means of combined normobaric oxygen breathing and intravascular perfluorocarbon (PFC) emulsions causing increased survival rate and faster bubble clearance from the intravascular compartment. The beneficial PFC effect...... has been explained by the increased transport capacity of oxygen and inert gases in blood. However, previous reports have shown that extravascular bubbles in lipid tissue of rats suffering from DCS will initially grow during oxygen breathing at normobaric conditions. We hypothesize that the combined...... effect of normobaric oxygen breathing and intravascular PFC infusion could lead to either enhanced extravascular bubble growth on decompression due to the increased oxygen supply, or that PFC infusion could lead to faster bubble elimination due to the increased solubility and transport capacity in blood...

  16. New principle for measuring arterial blood oxygenation, enabling motion-robust remote monitoring

    OpenAIRE

    Mark van Gastel; Sander Stuijk; Gerard de Haan

    2016-01-01

    Finger-oximeters are ubiquitously used for patient monitoring in hospitals worldwide. Recently, remote measurement of arterial blood oxygenation (SpO2) with a camera has been demonstrated. Both contact and remote measurements, however, require the subject to remain static for accurate SpO2 values. This is due to the use of the common ratio-of-ratios measurement principle that measures the relative pulsatility at different wavelengths. Since the amplitudes are small, they are easily corrupted ...

  17. Diode laser spectroscopy for noninvasive monitoring of oxygen in the lungs of newborn infants.

    Science.gov (United States)

    Svanberg, Emilie Krite; Lundin, Patrik; Larsson, Marcus; Åkeson, Jonas; Svanberg, Katarina; Svanberg, Sune; Andersson-Engels, Stefan; Fellman, Vineta

    2016-04-01

    Newborn infants may have pulmonary disorders with abnormal gas distribution, e.g., respiratory distress syndrome. Pulmonary radiography is the clinical routine for diagnosis. Our aim was to investigate a novel noninvasive optical technique for rapid nonradiographic bedside detection of oxygen gas in the lungs of full-term newborn infants. Laser spectroscopy was used to measure contents of oxygen gas (at 760 nm) and of water vapor (at 937 nm) in the lungs of 29 healthy newborn full-term infants (birth weight 2,900-3,900 g). The skin above the lungs was illuminated using two low-power diode lasers and diffusely emerging light was detected with a photodiode. Of the total 390 lung measurements performed, clear detection of oxygen gas was recorded in 60%, defined by a signal-to-noise ratio of >3. In all the 29 infants, oxygen was detected. Probe and detector positions for optimal pulmonary gas detection were determined. There were no differences in signal quality with respect to gender, body side or body weight. The ability to measure pulmonary oxygen content in healthy full-term neonates with this technique suggests that with further development, the method might be implemented in clinical practice for lung monitoring in neonatal intensive care.

  18. Carbon dioxide, oxygen, and pH detection in animal adipose tissue by means of extracorporeal microdialysis

    Science.gov (United States)

    Baldini, F.; Bizzarri, A.; Cajlakovic, M.; Feichtner, F.; Gianesello, L.; Giannetti, A.; Gori, G.; Konrad, C.; Mencaglia, A. A.; Mori, E.; Pavoni, V.; Perna, A. M.; Trono, C.

    2007-05-01

    Atypical physiological symptoms can be developed in healthy people under critically ill conditions. pH, pO II and pCO II are informative indicators of the conditions of a living system and can be valuable in determining the physiologic status of the critically ill patients. The continuous monitoring of these small molecules into the interstitial fluid (ISF) is a promising approach to reduce diagnostic blood loss and painful stress associated with blood sampling. Microdialysis is the approach followed for the extraction of the sample from the subcutaneous adipose tissue; the drawn interstitial fluid flows through a microfluidic circuit formed by the microdialysis catheter in series with a glass capillary on the internal wall of which the appropriate chemistry for sensing is immobilised. Absorption changes for pH sensor and modulation of the fluorescence lifetime for pO II and pCO II are the working principle. Phenol red covalently bound into the internal wall of a glass capillary by means of the Mannich reaction and platinum(II) tetrakis-pentafluorophenyl-porphyrine entrapped within a polymerised polystyrene layer are the chemical transducers used for pH and oxygen detection; the ion pair 8- hydroxypyrene-1,3,6-trisulfonic acid trisodium salt/ tetraoctylammonium hydroxide, dissolved in a silicon-based polymeric matrix, is used for the carbon dioxide detection. A suitable hemorrhagic shock model was developed in order to validate clinically the developed sensors in the condition of extreme stress and the obtained results show that the adipose tissue can become an alternative site for the continuous oitoring of pH, pO II and pCO II.

  19. Effects of topical negative pressure therapy on tissue oxygenation and wound healing in vascular foot wounds.

    Science.gov (United States)

    Chiang, Nathaniel; Rodda, Odette A; Sleigh, Jamie; Vasudevan, Thodur

    2017-08-01

    Topical negative pressure (TNP) therapy is widely used in the treatment of acute wounds in vascular patients on the basis of proposed multifactorial benefits. However, numerous recent systematic reviews have concluded that there is inadequate evidence to support its benefits at a scientific level. This study evaluated the changes in wound volume, surface area, depth, collagen deposition, and tissue oxygenation when using TNP therapy compared with traditional dressings in patients with acute high-risk foot wounds. This study was performed with hospitalized vascular patients. Forty-eight patients were selected with an acute lower extremity wound after surgical débridement or minor amputation that had an adequate blood supply without requiring further surgical revascularization and were deemed suitable for TNP therapy. The 22 patients who completed the study were randomly allocated to a treatment group receiving TNP or to a control group receiving regular topical dressings. Wound volume and wound oxygenation were analyzed using a modern stereophotographic wound measurement system and a hyperspectral transcutaneous oxygenation measurement system, respectively. Laboratory analysis was conducted on wound biopsy samples to determine hydroxyproline levels, a surrogate marker to collagen. Differences in clinical or demographic characteristics or in the location of the foot wounds were not significant between the two groups. All patients, with the exception of two, had diabetes. The two patients who did not have diabetes had end-stage renal failure. There was no significance in the primary outcome of wound volume reduction between TNP and control patients on day 14 (44.2% and 20.9%, respectively; P = .15). Analyses of secondary outcomes showed a significant result of better healing rates in the TNP group by demonstrating a reduction in maximum wound depth at day 14 (36.0% TNP vs 17.6% control; P = .03). No significant findings were found for the other outcomes of changes

  20. 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)

  1. Intracellular expression of reactive oxygen species-generating NADPH oxidase NOX4 in normal and cancer thyroid tissues

    NARCIS (Netherlands)

    Weyemi, Urbain; Caillou, Bernard; Talbot, Monique; Ameziane-El-Hassani, Rabii; Lacroix, Ludovic; Lagent-Chevallier, Odile; Al Ghuzlan, Abir; Roos, Dirk; Bidart, Jean-Michel; Virion, Alain; Schlumberger, Martin; Dupuy, Corinne

    2010-01-01

    NADPH oxidase 4 (NOX4) belongs to the NOX family that generates reactive oxygen species (ROS). Function and tissue distribution of NOX4 have not yet been entirely clarified. To date, in the thyroid gland, only DUOX1/2 NOX systems have been described. NOX4 mRNA expression, as shown by real-time PCR,

  2. Tumour oxygenation assessed by 18F-fluoromisonidazole PET and polarographic needle electrodes in human soft tissue tumours

    DEFF Research Database (Denmark)

    Bentzen, L.; Keiding, S.; Nordsmark, M.

    2003-01-01

    Background and purpose: The aim of the study was to identify hypoxia in human soft tissue sarcomas (STS) by PET scanning using the hypoxia marker [F-18]-fluoromisonidazole ([F-18]FMISO) and invasive oxygen sensitive probes (Eppendorf pO(2) Histograph, Germany). Materials and methods: Thirteen pat...

  3. Quantitative determination of localized tissue oxygen concentration in vivo by two-photon excitation phosphorescence lifetime measurements

    NARCIS (Netherlands)

    Mik, Egbert G.; van Leeuwen, Ton G.; Raat, Nicolaas J.; Ince, Can

    2004-01-01

    This study describes the use of two-photon excitation phosphorescence lifetime measurements for quantitative oxygen determination in vivo. Doubling the excitation wavelength of Pd-porphyrin from visible light to the infrared allows for deeper tissue penetration and a more precise and confined

  4. Simultaneous Blood–Tissue Exchange of Oxygen, Carbon Dioxide, Bicarbonate, and Hydrogen Ion

    Science.gov (United States)

    Dash, Ranjan K.; Bassingthwaighte, James B.

    2014-01-01

    A detailed nonlinear four-region (red blood cell, plasma, interstitial fluid, and parenchymal cell) axially distributed convection-diffusion-permeation-reaction-binding computational model is developed to study the simultaneous transport and exchange of oxygen (O2) and carbon dioxide (CO2) in the blood–tissue exchange system of the heart. Since the pH variation in blood and tissue influences the transport and exchange of O2 and CO2 (Bohr and Haldane effects), and since most CO2 is transported as HCO3- (bicarbonate) via the CO2 hydration (buffering) reaction, the transport and exchange of HCO3- and H+ are also simulated along with that of O2 and CO2. Furthermore, the model accounts for the competitive nonlinear binding of O2 and CO2 with the hemoglobin inside the red blood cells (nonlinear O2–CO2 interactions, Bohr and Haldane effects), and myoglobin-facilitated transport of O2 inside the parenchymal cells. The consumption of O2 through cytochrome-c oxidase reaction inside the parenchymal cells is based on Michaelis–Menten kinetics. The corresponding production of CO2 is determined by respiratory quotient (RQ), depending on the relative consumption of carbohydrate, protein, and fat. The model gives a physiologically realistic description of O2 transport and metabolism in the microcirculation of the heart. Furthermore, because model solutions for tracer transients and steady states can be computed highly efficiently, this model may be the preferred vehicle for routine data analysis where repetitive solutions and parameter optimization are required, as is the case in PET imaging for estimating myocardial O2 consumption. PMID:16775761

  5. In-vivo quantitative measurement of tissue oxygen saturation of human webbing using a transmission type continuous-wave near-infrared spectroscopy

    Science.gov (United States)

    Aizimu, Tuerxun; Adachi, Makoto; Nakano, Kazuya; Ohnishi, Takashi; Nakaguchi, Toshiya; Takahashi, Nozomi; Nakada, Taka-aki; Oda, Shigeto; Haneishi, Hideaki

    2018-02-01

    Near-infrared spectroscopy (NIRS) is a noninvasive method for monitoring tissue oxygen saturation (StO2). Many commercial NIRS devices are presently available. However, the precision of those devices is relatively poor because they are using the reflectance-model with which it is difficult to obtain the blood volume and other unchanged components of the tissue. Human webbing is a thin part of the hand and suitable to measure spectral transmittance. In this paper, we present a method for measuring StO2 of human webbing from a transmissive continuous-wave nearinfrared spectroscopy (CW-NIRS) data. The method is based on the modified Beer-Lambert law (MBL) and it consists of two steps. In the first step, we give a pressure to the upstream region of the measurement point to perturb the concentration of deoxy- and oxy-hemoglobin as remaining the other components and measure the spectral signals. From the measured data, spectral absorbance due to the components other than hemoglobin is calculated. In the second step, spectral measurement is performed at arbitrary time instance and the spectral absorbance obtained in the step 1 is subtracted from the measured absorbance. The tissue oxygen saturation (StO2) is estimated from the remained data. The method was evaluated on an arterial occlusion test (AOT) and a venous occlusion test (VOT). In the evaluation experiment, we confirmed that reasonable values of StO2 were obtained by the proposed method.

  6. Evaluating the Use of Tissue Oximetry to Decrease Intensive Unit Monitoring for Free Flap Breast Reconstruction.

    Science.gov (United States)

    Ricci, Joseph A; Vargas, Christina R; Ho, Olivia A; Lin, Samuel J; Tobias, Adam M; Lee, Bernard T

    2017-07-01

    Postoperative free flap care has historically required intensive monitoring for 24 hours in an intensive care unit. Continuous monitoring with tissue oximetry has allowed earlier detection of vascular compromise, decreasing flap loss and improving salvage. This study aims to identify whether a fast-track postoperative paradigm can be safely used with tissue oximetry to decrease intensive monitoring and costs. All consecutive microsurgical breast reconstructions performed at a single institution were reviewed (2008-2014) and cases requiring return to the operating room were identified. Data evaluated included patient demographics, the take back time course, and complications of flap loss and salvage. A cost-benefit analysis was performed to analyse the utility of a postoperative intensive monitoring setting. There were 900 flaps performed and 32 required an unplanned return to the operating room. There were 16 flaps that required a reexploration within the first 24 hours; the standard length of intensive unit monitoring. After 4 hours, there were 7 flaps (44%) detected by tissue oximetry for reexploration. After 15 hours of intensive monitoring postoperatively, cost analysis revealed that the majority (15/16; 94%) of failing flaps had been identified and the cost of identifying each subsequent failing flap exceeded the cost of another hour of intensive monitoring. The postoperative paradigm for microsurgical flaps has historically required intensive unit monitoring. Using tissue oximetry, a fast-track pathway can reduce time spent in an intensive monitoring setting from 24 to 15 hours with significant cost savings and minimal risk of missing a failing free flap.

  7. Assessment of muscle tissue oxygen saturation after out-of-hospital cardiac arrest.

    Science.gov (United States)

    Orban, Jean-Christophe; Scarlatti, Audrey; Danin, Pierre-Eric; Dellamonica, Jean; Bernardin, Gilles; Ichai, Carole

    2015-12-01

    Pathophysiology of cardiac arrest corresponds to an ischemia-reperfusion syndrome with deep impairment of microcirculation. Muscular tissue oxygen saturation (StO2) is a noninvasive method of evaluation of microcirculation. Our study was aimed at assessing the prognosis value of muscular StO2 in patients admitted for out-of-hospital cardiac arrest (OHCA) and treated with hypothermia. We conducted a prospective bicentric observational study including OHCA patients treated with therapeutic hypothermia. Baseline StO2, derived variables (desaturation and resaturation slopes), and lactate levels were compared at different times between patients with good and poor outcomes. Prognosis was assessed by the Cerebral Performance Category (CPC) score at 6 months after admission (CPC 1-2, good outcome; CPC 3-5, poor outcome). Forty-four patients were included, 17 good and 27 poor outcomes at 6 months. At admission, StO2 and lactate levels were lower in good outcome patients. Desaturation and resaturation slopes did not differ between groups. After an OHCA treated with therapeutic hypothermia, StO2 was correlated with outcome. Further research is needed to better understand the pathophysiological process underlying our results. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. 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...

  9. Effect of oxygen concentration on human embryo development evaluated by time-lapse monitoring

    DEFF Research Database (Denmark)

    Ingerslev, Hans Jakob; Hindkjær, Johnny Juhl; Kirkegaard, Kirstine

    2012-01-01

    -points for each cell division and blastocyst stages were registered until 120 hours after oocyte retrieval. Only 2PN embryos completing the first cleavage were evaluated. The groups were compared using one-way ANOVA or Kruskall-Wallis test. Estimates are reported as medians with 95% confidence intervals. Time......Introduction: Data from a number of studies indicate -but not unequivocally- that culture of embryos in 5% O2 compared to 20% O2 improves blastocyst formation in humans and various animal species and may yield better pregnancy rates in IVF. The detrimental effects of atmospheric oxygen were...... was to evaluate the influence of oxygen tension on human pre-implantation development using time-lapse monitoring. Materials and methods: Human embryos were cultured to the blastocyst stage in a time-lapse incubator (EmbryoScope™) in 20% O2 (group 1), 20% O2 for 24 hours followed by culture in 5% O2 (group 2...

  10. NAIL KERATIN AS MONITOR-TISSUE FOR SELENIUM EXPOSURE

    NARCIS (Netherlands)

    VANNOORD, PAH; MAAS, MJ; DEBRUIN, M

    1992-01-01

    Nail clippings might provide a way to monitor exposure to selenium in the recent past of an individual, since a clipping collected from a toe would reflect exposures months before actual clipping date. The relation between levels of exogenous selenium exposure and selenium levels in nail keratin was

  11. Magnetic resonance microscopy for monitoring osteogenesis in tissue-engineered construct in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Xu Huihui [Bioengineering Department (MC 063), University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL 60607-7052 (United States); Othman, Shadi F [Bioengineering Department (MC 063), University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL 60607-7052 (United States); Hong Liu [Bioengineering Department (MC 063), University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL 60607-7052 (United States); Peptan, Ioana A [Bioengineering Department (MC 063), University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL 60607-7052 (United States); Magin, Richard L [Bioengineering Department (MC 063), University of Illinois at Chicago, 851 South Morgan Street, Chicago, IL 60607-7052 (United States)

    2006-02-07

    Magnetic resonance microscopy (MRM) is used to monitor osteogenesis in tissue-engineered constructs. Measurements of the developing tissue's MR relaxation times (T{sub 1} and T{sub 2}), apparent diffusion coefficient (ADC) and elastic shear modulus were conducted over a 4-week growth period using an 11.74 T Bruker spectrometer with an imaging probe adapted for MR elastography (MRE). Both the relaxation times and the ADC show a statistically significant decrease after only one week of tissue development while the tissue stiffness increases progressively during the first two weeks of in vitro growth. The measured MR parameters are correlated with histologically monitored osteogenic tissue development. This study shows that MRM can provide quantitative data with which to characterize the growth and development of tissue-engineered bone.

  12. Characterization of positron emission tomography hypoxia tracer uptake and tissue oxygenation via electrochemical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, Stephen R., E-mail: srbowen@wisc.edu [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); Kogel, Albert J. van der [University Medical Centre St. Radboud, Nijmegen (Netherlands); Nordsmark, Marianne [Aarhus University Hospital, Department of Experimental Clinical Oncology, Aarhus (Denmark); Bentzen, Soren M. [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); University of Wisconsin School of Medicine and Public Health, Department of Human Oncology, Clinical Sciences Center, Madison, WI 53792 (United States); Jeraj, Robert [University of Wisconsin School of Medicine and Public Health, Department of Medical Physics, Madison, WI 53706 (United States); University of Wisconsin School of Medicine and Public Health, Department of Human Oncology, Clinical Sciences Center, Madison, WI 53792 (United States); Jozef Stefan Institute, Jamova 39, 1000 Ljubljana (Slovenia)

    2011-08-15

    Purpose: Unique uptake and retention mechanisms of positron emission tomography (PET) hypoxia tracers make in vivo comparison between them challenging. Differences in imaged uptake of two common hypoxia radiotracers, [{sup 61}Cu]Cu-ATSM and [{sup 18}F]FMISO, were characterized via computational modeling to address these challenges. Materials and Methods: An electrochemical formalism describing bioreductive retention mechanisms of these tracers under steady-state conditions was adopted to relate time-averaged activity concentration to tissue partial oxygen tension (PO{sub 2}), a common metric of hypoxia. Chemical equilibrium constants of product concentration to reactant concentration ratios were determined from free energy changes and reduction potentials of pertinent reactions reported in the literature. Resulting transformation functions between tracer uptake and PO{sub 2} were compared against measured values in preclinical models. Additionally, calculated PO{sub 2} distributions from imaged Cu-ATSM tracer activity concentrations of 12 head and neck squamous cell carcinoma (HNSCC) patients were validated against microelectrode PO{sub 2} measurements in 69 HNSCC patients. Results: Both Cu-ASTM- and FMISO-modeled PO{sub 2} transformation functions were in agreement with preclinical measured values within single-deviation confidence intervals. High correlation (r{sup 2}=0.94, P<.05) was achieved between modeled PO{sub 2} distributions and measured distributions in the patient populations. On average, microelectrode hypoxia thresholds (2.5 and 5.0 mmHg) corresponded to higher Cu-ATSM uptake [2.5 and 2.0 standardized uptake value (SUV)] and lower FMISO uptake (2.0 and 1.4 SUV). Uncertainties in the models were dominated by variations in the estimated specific activity and intracellular acidity. Conclusions: Results indicated that the high dynamic range of Cu-ATSM uptake was representative of a narrow range of low oxygen tension whose values were dependent on

  13. Mathematics applied to radiotherapy problem: oxygen diffusion in live tissues; La matematica aplicada en un problema de radioterapia: la difusion de oxigeno en los tejidos vivos

    Energy Technology Data Exchange (ETDEWEB)

    Moyano, Edgardo A.; Dominici, Diego E. [Comision Nacional de Energia Atomica, Buenos Aires (Argentina)

    1996-07-01

    It is known that the oxygenation of living tissues increases the effect of irradiation. Thus it's convenient to oxygen tumor tissues and to know, before irradiation, the change of concentration of available oxygen already in it, between the sealed surface and the furthest depth of penetration or interface. In the present work we solve a model proposed by J. Cranck and R. Gupta, that describes thediffusion of oxygen in living tissues. Landau's transformation we used and finite differences for approximating the problem. We describe two implicit algorithms. The transformation allows to work with a fixed number of nodes during all the simulation. (author)

  14. Evaluation of different near-infrared spectroscopy technologies for assessment of tissue oxygen saturation during a vascular occlusion test.

    Science.gov (United States)

    Steenhaut, Kevin; Lapage, Koen; Bové, Thierry; De Hert, Stefan; Moerman, Annelies

    2017-12-01

    An increasing number of NIRS devices are used to provide measurements of peripheral tissue oxygen saturation (S t O 2 ). The aim of the present study is to test the hypothesis that despite technological differences between devices, similar trend values will be obtained during a vascular occlusion test. The devices compared are NIRO-200NX, which measures S t O 2 and oxyhemoglobin by spatially resolved spectroscopy and the Beer-Lambert law, respectively, and INVOS 5100C and Foresight Elite, which both measure S t O 2 with the Beer-Lambert law, enhanced with the spatial resolution technique. Forty consenting adults scheduled for CABG surgery were recruited. The respective sensors of the three NIRS devices were applied over the brachioradial muscle. Before induction of anesthesia, 3 min of ischemia were induced by inflating a blood pressure cuff at the upper arm, whereafter cuff pressure was rapidly released. Tissue oxygenation measurements included baseline, minimum and maximum values, desaturation and resaturation slopes, and rise time. Comparisons between devices were performed with the Kruskal-Wallis test with post hoc Mann-Whitney pairwise comparisons. Agreement was evaluated using Bland-Altman plots. Oxyhemoglobin measured with NIRO responded faster than the other NIRS technologies to changes in peripheral tissue oxygenation (20 vs. 27-40 s, p ≤ 0.01). When comparing INVOS with Foresight, oxygenation changes were prompter (upslope 311 [92-523]%/min vs. 114[65-199]%/min, p ≤ 0.01) and more pronounced (minimum value 36 [21-48] vs. 45 [40-51]%, p ≤ 0.01) with INVOS. Significant differences in tissue oxygen saturation measurements were observed, both within the same device as between different devices using the same measurement technology.

  15. Substrate stiffness and oxygen as regulators of stem cell differentiation during skeletal tissue regeneration: a mechanobiological model.

    Directory of Open Access Journals (Sweden)

    Darren Paul Burke

    Full Text Available Extrinsic mechanical signals have been implicated as key regulators of mesenchymal stem cell (MSC differentiation. It has been possible to test different hypotheses for mechano-regulated MSC differentiation by attempting to simulate regenerative events such as bone fracture repair, where repeatable spatial and temporal patterns of tissue differentiation occur. More recently, in vitro studies have identified other environmental cues such as substrate stiffness and oxygen tension as key regulators of MSC differentiation; however it remains unclear if and how such cues determine stem cell fate in vivo. As part of this study, a computational model was developed to test the hypothesis that substrate stiffness and oxygen tension regulate stem cell differentiation during fracture healing. Rather than assuming mechanical signals act directly on stem cells to determine their differentiation pathway, it is postulated that they act indirectly to regulate angiogenesis and hence partially determine the local oxygen environment within a regenerating tissue. Chondrogenesis of MSCs was hypothesized to occur in low oxygen regions, while in well vascularised regions of the regenerating tissue a soft local substrate was hypothesised to facilitate adipogenesis while a stiff substrate facilitated osteogenesis. Predictions from the model were compared to both experimental data and to predictions of a well established computational mechanobiological model where tissue differentiation is assumed to be regulated directly by the local mechanical environment. The model predicted all the major events of fracture repair, including cartilaginous bridging, endosteal and periosteal bony bridging and bone remodelling. It therefore provides support for the hypothesis that substrate stiffness and oxygen play a key role in regulating MSC fate during regenerative events such as fracture healing.

  16. [The effects of oxygen partial pressure changes on the osteometric markers of the bone tissue in rats].

    Science.gov (United States)

    Berezovs'kyĭ, V Ia; Zamors'ka, T M; Ianko, R V

    2013-01-01

    Our purpose was to investigate the oxygen partial pressure changes on the osteometric and biochemical markers of bone tissue in rats. It was shown that breathing of altered gas mixture did not change the mass, general length, sagittal diameter and density thigh-bones in 12-month Wistar male-rats. The dosed normobaric hypoxia increased the activity of alkaline phosphatase and decreased the activity of tartrate-resistant acid phosphatase. At the same time normobaric hyperoxia with 40 and 90% oxygen conversely decreased the activity of alkaline phosphatase and increased the activity of tartrate-resistant acid phosphatase.

  17. Real-Time In Vivo Monitoring of Reactive Oxygen Species in Guard Cells.

    Science.gov (United States)

    Park, Ky Young; Roubelakis-Angelakis, Kalliopi A

    2018-01-01

    The intra-/intercellular homeostasis of reactive oxygen species (ROS), and especially of superoxides (O 2 .- ) and hydrogen peroxide (O 2 .- ) participate in signalling cascades which dictate developmental processes and reactions to biotic/abiotic stresses. Polyamine oxidases terminally oxidize/back convert polyamines generating H 2 O 2 . Recently, an NADPH-oxidase/Polyamine oxidase feedback loop was identified to control oxidative burst under salinity. Thus, the real-time localization/monitoring of ROS in specific cells, such as the guard cells, can be of great interest. Here we present a detailed description of the real-time in vivo monitoring of ROS in the guard cells using H 2 O 2 - and O 2 .- specific fluorescing probes, which can be used for studying ROS accumulation generated from any source, including the amine oxidases-dependent pathway, during development and stress.

  18. Characterization of Adipose Tissue Product Quality Using Measurements of Oxygen Consumption Rate.

    Science.gov (United States)

    Suszynski, Thomas M; Sieber, David A; Mueller, Kathryn; Van Beek, Allen L; Cunningham, Bruce L; Kenkel, Jeffrey M

    2018-03-14

    Fat grafting is a common procedure in plastic surgery but associated with unpredictable graft retention. Adipose tissue (AT) "product" quality is affected by the methods used for harvest, processing and transfer, which vary widely amongst surgeons. Currently, there is no method available to accurately assess the quality of AT. In this study, we present a novel method for the assessment of AT product quality through direct measurements of oxygen consumption rate (OCR). OCR has exhibited potential in predicting outcomes following pancreatic islet transplant. Our study aim was to reapportion existing technology for its use with AT preparations and to confirm that these measurements are feasible. OCR was successfully measured for en bloc and postprocessed AT using a stirred microchamber system. OCR was then normalized to DNA content (OCR/DNA), which represents the AT product quality. Mean (±SE) OCR/DNA values for fresh en bloc and post-processed AT were 149.8 (± 9.1) and 61.1 (± 6.1) nmol/min/mg DNA, respectively. These preliminary data suggest that: (1) OCR and OCR/DNA measurements of AT harvested using conventional protocol are feasible; and (2) standard AT processing results in a decrease in overall AT product quality. OCR measurements of AT using existing technology can be done and enables accurate, real-time, quantitative assessment of the quality of AT product prior to transfer. The availability and further validation of this type of assay could enable optimization of fat grafting protocol by providing a tool for the more detailed study of procedural variables that affect AT product quality.

  19. The design of a PC-based real-time system for monitoring Methane and Oxygen concentration in biogas production

    Science.gov (United States)

    Yantidewi, M.; Muntini, M. S.; Deta, U. A.; Lestari, N. A.

    2018-03-01

    Limited fossil fuels nowadays trigger the development of alternative energy, one of which is biogas. Biogas is one type of bioenergy in the form of fermented gases of organic materials such as animal waste. The components of gases present in biogas and affect the biogas production are various, such as methane and oxygen. The biogas utilization will be more optimal if both gases concentration (in this case is methane and oxygen concentration) can be monitored. Therefore, this research focused on designing the monitoring system of methane and oxygen concentration in biogas production in real-time. The results showed that the instrument system was capable of monitoring and recording the data of gases (methane and oxygen) concentration in biogas production in every second.

  20. Cerebral oxygenation monitoring in patients with bilateral carotid stenosis undergoing urgent cardiac surgery: Observational case series

    Directory of Open Access Journals (Sweden)

    Dincer Aktuerk

    2016-01-01

    Full Text Available Background: Patients with significant bilateral carotid artery stenosis requiring urgent cardiac surgery have an increased risk of stroke and death. The optimal management strategy remains inconclusive, and the available evidence does not support the superiority of one strategy over another. Materials and Methods: A number of noninvasive strategies have been developed for minimizing perioperative stroke including continuous real-time monitoring of cerebral oxygenation with near-infrared spectroscopy (NIRS. The number of patients presenting with this combination (bilateral significant carotid stenosis requiring urgent cardiac surgery in any single institution will be small and hence there is a lack of large randomized studies. Results: This case series describes our early experience with NIRS in a select group of patients with significant bilateral carotid stenosis undergoing urgent cardiac surgery (n = 8. In contrast to other studies, this series is a single surgeon, single center study, where the entire surgery (both distal ends and proximal ends was performed during single aortic clamp technique, which effectively removes several confounding variables. NIRS monitoring led to the early recognition of decreased cerebral oxygenation, and corrective steps (increased cardiopulmonary bypass flow, increased pCO 2 , etc., were taken. Conclusion: The study shows good clinical outcome with the use of NIRS. This is our "work in progress," and we aim to conduct a larger study.

  1. In-vivo continuous monitoring of mixed venous oxygen saturation by photoacoustic transesophageal echocardiography (Conference Presentation)

    Science.gov (United States)

    Li, Li; Subramaniam, Balachundhar; Aguirre, Aaron D.; Andrawes, Michael N.; Tearney, Guillermo J.

    2016-02-01

    Mixed venous oxygen saturation (SvO2), measured from pulmonary arteries, is a gold-standard measure of the dynamic balance between the oxygen supply and demand in the body. In critical care, continuous monitoring of SvO2 plays a vital role in early detection of circulatory shock and guiding goal-oriented resuscitation. In current clinical practice, SvO2 is measured by invasive pulmonary artery catheters (PAC), which are associated with a 10% risk of severe complications. To address the unmet clinical need for a non-invasive SvO2 monitor, we are developing a new technology termed photoacoustic transesophageal echocardiography (PA-TEE). PA-TEE integrates transesophageal echocardiography with photoacoustic oximetry, and enables continuous assessment of SvO2 through an esophageal probe that can be inserted into the body in a minimally invasive manner. We have constructed a clinically translatable PA-TEE prototype, which features a mobile OPO laser, a modified ultrasonography console and a dual-modality esophageal probe. Comprised of a rotatable acoustic array detector, a flexible optical fiber bundle and a light-integrating acoustic lens, the oximetric probe has an outer diameter smaller than 15 mm and will be tolerable for most patients. Through custom-made C++/Qt software, our device acquires and displays ultrasonic and photoacoustic images in real time to guide the deployment of the probe. SvO2 is calculated on-line and updated every second. PA-TEE has now been used to evaluate SvO2 in living swine. Our findings show that changing the fraction of oxygen in the inspired gas modulates SvO2 measured by PA-TEE. Statistic comparison between SvO2 measurements from PA-TEE in vivo the gold-standard laboratorial analysis on blood samples drawn from PACs will be presented.

  2. Noninvasive diffuse optical monitoring of head and neck tumor blood flow and oxygenation during radiation delivery

    Science.gov (United States)

    Dong, Lixin; Kudrimoti, Mahesh; Cheng, Ran; Shang, Yu; Johnson, Ellis L.; Stevens, Scott D.; Shelton, Brent J.; Yu, Guoqiang

    2012-01-01

    This study explored using a novel diffuse correlation spectroscopy (DCS) flow-oximeter to noninvasively monitor blood flow and oxygenation changes in head and neck tumors during radiation delivery. A fiber-optic probe connected to the DCS flow-oximeter was placed on the surface of the radiologically/clinically involved cervical lymph node. The DCS flow-oximeter in the treatment room was remotely operated by a computer in the control room. From the early measurements, abnormal signals were observed when the optical device was placed in close proximity to the radiation beams. Through phantom tests, the artifacts were shown to be caused by scattered x rays and consequentially avoided by moving the optical device away from the x-ray beams. Eleven patients with head and neck tumors were continually measured once a week over a treatment period of seven weeks, although there were some missing data due to the patient related events. Large inter-patient variations in tumor hemodynamic responses were observed during radiation delivery. A significant increase in tumor blood flow was observed at the first week of treatment, which may be a physiologic response to hypoxia created by radiation oxygen consumption. Only small and insignificant changes were found in tumor blood oxygenation, suggesting that oxygen utilizations in tumors during the short period of fractional radiation deliveries were either minimal or balanced by other effects such as blood flow regulation. Further investigations in a large patient population are needed to correlate the individual hemodynamic responses with the clinical outcomes for determining the prognostic value of optical measurements. PMID:22312579

  3. Polymer Electrolyte-Based Ambient Temperature Oxygen Microsensors for Environmental Monitoring

    Science.gov (United States)

    Hunter, Gary W.; Xu, Jennifer C.; Liu, Chung-Chiun

    2011-01-01

    An ambient temperature oxygen microsensor, based on a Nafion polymer electrolyte, has been developed and was microfabricated using thin-film technologies. A challenge in the operation of Nafion-based sensor systems is that the conductivity of Nafion film depends on the humidity in the film. Nafion film loses conductivity when the moisture content in the film is too low, which can affect sensor operation. The advancement here is the identification of a method to retain the operation of the Nafion films in lower humidity environments. Certain salts can hold water molecules in the Nafion film structure at room temperature. By mixing salts with the Nafion solution, water molecules can be homogeneously distributed in the Nafion film increasing the film s hydration to prevent Nafion film from being dried out in low-humidity environment. The presence of organics provides extra sites in the Nafion film to promote proton (H+) mobility and thus improving Nafion film conductivity and sensor performance. The fabrication of ambient temperature oxygen microsensors includes depositing basic electrodes using noble metals, and metal oxides layer on one of the electrode as a reference electrode. The use of noble metals for electrodes is due to their strong catalytic properties for oxygen reduction. A conducting polymer Nafion, doped with water-retaining components and extra sites facilitating proton movement, was used as the electrolyte material, making the design adequate for low humidity environment applications. The Nafion solution was coated on the electrodes and air-dried. The sensor operates at room temperature in potentiometric mode, which measures voltage differences between working and reference electrodes in different gases. Repeat able responses to 21-percent oxygen in nitrogen were achieved using nitrogen as a baseline gas. Detection of oxygen from 7 to 21 percent has also been demonstrated. The room-temperature oxygen micro sensor developed has extremely low power

  4. Oxygen limitation and tissue metabolic potential of the African fish Barbus neumayeri: roles of native habitat and acclimatization

    Directory of Open Access Journals (Sweden)

    Rees Bernard B

    2011-01-01

    Full Text Available Abstract Background Oxygen availability in aquatic habitats is a major environmental factor influencing the ecology, behaviour, and physiology of fishes. This study evaluates the contribution of source population and hypoxic acclimatization of the African fish, Barbus neumayeri, in determining growth and tissue metabolic enzyme activities. Individuals were collected from two sites differing dramatically in concentration of dissolved oxygen (DO, Rwembaita Swamp (annual average DO 1.35 mgO2 L-1 and Inlet Stream West (annual average DO 5.58 mgO2 L-1 in Kibale National Park, Uganda, and reciprocally transplanted using a cage experiment in the field, allowing us to maintain individuals under natural conditions of oxygen, food availability, and flow. Fish were maintained under these conditions for four weeks and sampled for growth rate and the activities of phosphofructokinase (PFK, lactate dehydrogenase (LDH, citrate synthase (CS, and cytochrome c oxidase (CCO in four tissues, liver, heart, brain, and skeletal muscle. Results Acclimatization to the low DO site resulted in lower growth rates, lower activities of the aerobic enzyme CCO in heart, and higher activities of the glycolytic enzyme PFK in heart and skeletal muscle. The activity of LDH in liver tissue was correlated with site of origin, being higher in fish collected from a hypoxic habitat, regardless of acclimatization treatment. Conclusions Our results suggest that the influence of site of origin and hypoxic acclimatization in determining enzyme activity differs among enzymes and tissues, but both factors contribute to higher glycolytic capacity and lower aerobic capacity in B. neumayeri under naturally-occurring conditions of oxygen limitation.

  5. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project.

    Science.gov (United States)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-04-07

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery.

  6. Study and Development of a Fluorescence Based Sensor System for Monitoring Oxygen in Wine Production: The WOW Project

    Science.gov (United States)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of the winemaking process, both for monitoring and for control. The WOW project (Deployment of WSAN technology for monitoring Oxygen in Wine products) has focused on the design and the development of an innovative device for monitoring the oxygen levels in wine. This system is based on the use of an optical fiber to measure the luminescent lifetime variation of a reference metal/porphyrin complex, which decays in presence of oxygen. The developed technology results in a high sensitivity and low cost sensor head that can be employed for measuring the dissolved oxygen levels at several points inside a wine fermentation or aging tank. This system can be complemented with dynamic modeling techniques to provide predictive behavior of the nutrient evolution in space and time given few sampled measuring points, for both process monitoring and control purposes. The experimental validation of the technology has been first performed in a controlled laboratory setup to attain calibration and study sensitivity with respect to different photo-luminescent compounds and alcoholic or non-alcoholic solutions, and then in an actual case study during a measurement campaign at a renown Italian winery. PMID:29642468

  7. LASER BIOLOGY AND MEDICINE: Optoacoustic laser monitoring of cooling and freezing of tissues

    Science.gov (United States)

    Larin, Kirill V.; Larina, I. V.; Motamedi, M.; Esenaliev, R. O.

    2002-11-01

    Real-time monitoring of cooling and freezing of tissues, cells, and other biological objects with a high spatial and time resolution, which is necessary for selective destruction of cancer and benign tumours during cryotherapy, as well as for preventing any damage to the structure and functioning of biological objects in cryobiology, is considered. The optoacoustic method, based on the measurement and analysis of acoustic waves induced by short laser pulses, is proposed for monitoring the cooling and freezing of the tissue. The effect of cooling and freezing on the amplitude and time profile of acoustic signals generated in real tissues and in a model object is studied. The experimental results indicate that the optoacoustic laser technique can be used for real-time monitoring of cooling and freezing of biological objects with a submillimeter spatial resolution and a high contrast.

  8. Monitoring mixed venous oxygen saturation in patients with obstructive shock after massive pulmonary embolism.

    Science.gov (United States)

    Krivec, Bojan; Voga, Gorazd; Podbregar, Matej

    2004-05-31

    Patients with massive pulmonary embolism and obstructive shock usually require hemodynamic stabilization and thrombolysis. Little is known about the optimal and proper use of volume infusion and vasoactive drugs, or about the titration of thrombolytic agents in patients with relative contraindication for such treatment. The aim of the study was to find the most rapidly changing hemodynamic variable to monitor and optimize the treatment of patients with obstructive shock following massive pulmonary embolism. Ten consecutive patients hospitalized in the medical intensive care unit in the community General Hospital with obstructive shock following massive pulmonary embolism were included in the prospective observational study. Heart rate, systolic arterial pressure, central venous pressure, mean pulmonary-artery pressure, cardiac index, total pulmonary vascular-resistance index, mixed venous oxygen saturation, and urine output were measured on admission and at 1, 2, 3, 4, 8, 12, and 16 hours. Patients were treated with urokinase through the distal port of a pulmonary-artery catheter. At 1 hour, mixed venous oxygen saturation, systolic arterial pressure and cardiac index were higher than their admission values (31+/-10 vs. 49+/-12%, p<0.0001; 86+/-12 vs. 105+/-17 mmHg, p<0.01; 1.5+/-0.4 vs. 1.9+/-0.7 L/min/m2, p<0.05; respectively), whereas heart rate, central venous pressure, mean pulmonary-artery pressure and urine output remained unchanged. Total pulmonary vascular-resistance index was lower than at admission (29+/-10 vs. 21+/-12 mmHg/L/min/m2, p<0.05). The relative change of mixed venous oxygen saturation at hour 1 was higher than the relative changes of all other studied variables (p<0.05). Serum lactate on admission and at 12 hours correlated to mixed venous oxygen saturation (r=-0.855, p<0.001). In obstructive shock after massive pulmonary embolism, mixed venous oxygen saturation changes more rapidly than other standard hemodynamic variables.

  9. Oxidative stress under ambient and physiological oxygen tension in tissue culture

    Science.gov (United States)

    Jagannathan, Lakshmanan; Cuddapah, Suresh; Costa, Max

    2016-01-01

    Oxygen (O2) levels range from 2–9% in vivo. However, cell culture experiments are performed at atmospheric O2 levels (21%). Oxidative stress due to generation of reactive oxygen species (ROS) in cells cultured at higher than physiological levels is implicated in multitude of deleterious effects including DNA damage, genomic instability and senescence. In addition, oxidative stress activates redox sensitive transcription factors related to inflammatory signaling and apoptotic signaling. Furthermore, several chromatin-modifying enzymes are affected by ROS, potentially impacting epigenetic regulation of gene expression. While primary cells are cultured at lower O2 levels due to their inability to grow at higher O2, the immortalized cells, which display no such apparent growth difficulties, are typically cultured at 21% O2. This review will provide an overview of issues associated with increased oxygen levels in in vitro cell culture and point out the benefits of using lower levels of oxygen tension even for immortalized cells. PMID:27034917

  10. 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...

  11. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

    OpenAIRE

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten; Lauritzen, Martin

    2012-01-01

    Glial calcium (Ca2+) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen saturation alters wave activity; (2) glial Ca2+ waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of...

  12. Effect of oxygen concentration on human embryo development evaluated by time-lapse monitoring

    DEFF Research Database (Denmark)

    Ingerslev, Hans Jakob; Hindkjær, Johnny Juhl; Kirkegaard, Kirstine

    2012-01-01

    recently demonstrated to occur from first cleavage cycle in mice using time-lapse microscopy, with the largest impact on the pre-compaction stages. However, embryonic development in mice differs in many aspects from human embryonic development. The objective of this retrospective, descriptive study...... was to evaluate the influence of oxygen tension on human pre-implantation development using time-lapse monitoring. Materials and methods: Human embryos were cultured to the blastocyst stage in a time-lapse incubator (EmbryoScope™) in 20% O2 (group 1), 20% O2 for 24 hours followed by culture in 5% O2 (group 2......) or in 5% O2 (group 3). Eligible were patients with age 8 oocytes retrieved. Group 1 consisted of 120 IVF/ICSI embryos from 26 patients recruited to a study conducted to evaluate the safety of the time-lapse incubator by randomising 1:1 embryos from a patient to culture...

  13. Effects of in vitro low oxygen tension preconditioning of adipose stromal cells on their in vivo chondrogenic potential: application in cartilage tissue repair.

    Directory of Open Access Journals (Sweden)

    Sophie Portron

    Full Text Available PURPOSE: Multipotent stromal cell (MSC-based regenerative strategy has shown promise for the repair of cartilage, an avascular tissue in which cells experience hypoxia. Hypoxia is known to promote the early chondrogenic differentiation of MSC. The aim of our study was therefore to determine whether low oxygen tension could be used to enhance the regenerative potential of MSC for cartilage repair. METHODS: MSC from rabbit or human adipose stromal cells (ASC were preconditioned in vitro in control or chondrogenic (ITS and TGF-β medium and in 21 or 5% O2. Chondrogenic commitment was monitored by measuring COL2A1 and ACAN expression (real-time PCR. Preconditioned rabbit and human ASC were then incorporated into an Si-HPMC hydrogel and injected (i into rabbit articular cartilage defects for 18 weeks or (ii subcutaneously into nude mice for five weeks. The newly formed tissue was qualitatively and quantitatively evaluated by cartilage-specific immunohistological staining and scoring. The phenotype of ASC cultured in a monolayer or within Si-HPMC in control or chondrogenic medium and in 21 or 5% O2 was finally evaluated using real-time PCR. RESULTS/CONCLUSIONS: 5% O2 increased the in vitro expression of chondrogenic markers in ASC cultured in induction medium. Cells implanted within Si-HPMC hydrogel and preconditioned in chondrogenic medium formed a cartilaginous tissue, regardless of the level of oxygen. In addition, the 3D in vitro culture of ASC within Si-HPMC hydrogel was found to reinforce the pro-chondrogenic effects of the induction medium and 5% O2. These data together indicate that although 5% O2 enhances the in vitro chondrogenic differentiation of ASC, it does not enhance their in vivo chondrogenesis. These results also highlight the in vivo chondrogenic potential of ASC and their potential value in cartilage repair.

  14. Cell microenvironment engineering and monitoring for tissue engineering and regenerative medicine: the recent advances.

    Science.gov (United States)

    Barthes, Julien; Özçelik, Hayriye; Hindié, Mathilde; Ndreu-Halili, Albana; Hasan, Anwarul; Vrana, Nihal Engin

    2014-01-01

    In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells' behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future.

  15. Cell Microenvironment Engineering and Monitoring for Tissue Engineering and Regenerative Medicine: The Recent Advances

    Directory of Open Access Journals (Sweden)

    Julien Barthes

    2014-01-01

    Full Text Available In tissue engineering and regenerative medicine, the conditions in the immediate vicinity of the cells have a direct effect on cells’ behaviour and subsequently on clinical outcomes. Physical, chemical, and biological control of cell microenvironment are of crucial importance for the ability to direct and control cell behaviour in 3-dimensional tissue engineering scaffolds spatially and temporally. In this review, we will focus on the different aspects of cell microenvironment such as surface micro-, nanotopography, extracellular matrix composition and distribution, controlled release of soluble factors, and mechanical stress/strain conditions and how these aspects and their interactions can be used to achieve a higher degree of control over cellular activities. The effect of these parameters on the cellular behaviour within tissue engineering context is discussed and how these parameters are used to develop engineered tissues is elaborated. Also, recent techniques developed for the monitoring of the cell microenvironment in vitro and in vivo are reviewed, together with recent tissue engineering applications where the control of cell microenvironment has been exploited. Cell microenvironment engineering and monitoring are crucial parts of tissue engineering efforts and systems which utilize different components of the cell microenvironment simultaneously can provide more functional engineered tissues in the near future.

  16. The significance of monitoring sex hormones levels after ovarian tissue auto-transplantation

    International Nuclear Information System (INIS)

    Wang Qiuwei; Xu Peizhen; Yu Bin; Zhou Hong

    2003-01-01

    Objective: To evaluate the significance of monitoring serum sex hormones levels after ovarian tissue auto-transplantation. Methods: Twenty-five patients with stage IV recurrent endometriosis after one or two times of conservative surgeries underwent radical surgery. Their ovarian tissue fragments were transplanted to greater omentum. Serum follicle-stimulation hormone (FSH), Luteinizing hormone (LH) and estradiol (E 2 ) levels were measured monthly since fourth month post-operatively. After E 2 was increased, based body temperature was measured and vaginal hormone cytology was examined weekly for maturation index (MI) to assess the ovulatory phase and luteal phase in those with viable ovarian tissues. Serum levels of FSH, LH and E 2 in ovulatory phase and luteal phase were determined 20 women with viable ovarian tissues for three cycles as well as in 20 normal sexually mature women and 20 operative menopausal women. Results: There were 12 cases who had increasing of E 2 at four months post operatively and 8 cases more at six months. The other 5 cases with low serum E 2 levels and high FSH and LH levels at 12 months were designated as failures. The survival rate of transplanted ovarian tissue was 80.0%. There were no significant differences of the serum FSH, LH and E 2 levels in ovulatory phase and luteal phase between women with viable grafted ovarian tissues and normal sexually mature women. Conclusion: Monitoring of sex hormones is a good means to assess the viability of the transplanted ovarian tissue fragments

  17. 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

  18. Multi-Fibre Optode Microsensors: affordable designs for monitoring oxygen in soils under varying environmental conditions

    Science.gov (United States)

    Rezanezhad, F.; Milojevic, T.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2017-12-01

    Molecular oxygen (O2) measurements in field and laboratory soil and sediment systems provide useful insight into the biogeochemical functioning of natural environments. However, monitoring soil and sediment O2 is often challenging due to high costs, analyte consumption, and limited customizability and durability of existing O2 sensors. To meet this challenge, an in-house luminescence-based Multi Fibre Optode (MuFO) microsensor system was developed to monitor O2 levels under changing moisture and temperature regimes. The design is simplified by the use of a basic DSLR camera, LED light and fibre optic cables. The technique is based on O2 quenching the luminescent light intensity emitted from a luminophore (platinum(II) meso-tetra(pentafluorophenyl)porphyrin, PtTFPP) that is dip-coated onto the tips of the fibre optic cables, where increasing O2 corresponds to decreasing light intensity, based on the classic Stern-Volmer relationship. High-resolution digital images of the sensor-emitted light are then converted into % O2 saturation. The method was successfully tested in two artificial soil (20% peat, 80% sand) column experiments designed to simulate freeze-thaw cycles (temperature cycling from -10°C to 25°C) and water table fluctuations under controlled conditions. Depth distributions of O2 levels were monitored without interruption for multiple freeze-thaw and water table cycles. No degradation of optode performance or O2 signals were observed for the duration of the column experiments, which supports the long-term deployment of the microsensors for continuous O2 monitoring in field and laboratory settings. The technical specifications of the system are fair, with a detection limit of 0.2% O2 saturation. The main advantages of the MuFO system over commercial applications are the comparatively low cost ($1,800 USD; about ¼ the cost of commercial versions) and ease of customizability. The system has been further developed for near real-time monitoring in the field

  19. Real time continuous oxygen concentration monitoring system during malaxation for the production of Virgin Olive Oil

    Directory of Open Access Journals (Sweden)

    Aiello, G.

    2012-10-01

    Full Text Available During the mechanical extraction process of Virgin Olive Oil (VOO some important physical phenomena and enzymatic transformations occur which influence the quality of the final product. The control of process parameters is crucial to ensure the quality of VOO, therefore process monitoring and control is a fundamental requirement in the modern VOO processing industry. The present work proposes an innovative Real-Time Monitoring System (RTMS aimed at continuously measuring the oxygen concentration during the malaxation process in order to establish a correlation with the quality of the final product obtained. This monitoring system is based on an oxygen concentration sensor directly connected to the malaxation chamber and a data acquisition system to analyze and store the measured values in a process database. The experimental results obtained show that the use of oxygen during malaxation improves some qualitative parameters of VOO such as free fatty acids and total polyphenols while others (peroxide values and spectrophotometric indexes worsen. These results are similar to those obtained by employing nitrogen, which is the traditional technique to avoid the wellknown oxidation processes studied by several researchers, thus demonstrating that the presence of oxygen during the malaxation process can have beneficial effects on the quality of VOO when its concentration is properly controlled.

    Durante el proceso de extracción mecánica del aceite de oliva virgen ocurren importantes fenómenos físicos y transformaciones enzimáticas que influyen en la calidad del producto final. El control de los parámetros del proceso es crucial para garantizar la calidad del aceite de oliva virgen, por tanto la monitorización y el control del proceso son requisitos fundamentales en el moderno tratamiento industrial del aceite de oliva virgen. El presente trabajo propone un sistema de monitorización innovador en tiempo real dirigido a medir continuamente

  20. Monitoring temporal microstructural variations of skeletal muscle tissues by multispectral Mueller matrix polarimetry

    Science.gov (United States)

    Dong, Yang; He, Honghui; He, Chao; Ma, Hui

    2017-02-01

    Mueller matrix polarimetry is a powerful tool for detecting microscopic structures, therefore can be used to monitor physiological changes of tissue samples. Meanwhile, spectral features of scattered light can also provide abundant microstructural information of tissues. In this paper, we take the 2D multispectral backscattering Mueller matrix images of bovine skeletal muscle tissues, and analyze their temporal variation behavior using multispectral Mueller matrix parameters. The 2D images of the Mueller matrix elements are reduced to the multispectral frequency distribution histograms (mFDHs) to reveal the dominant structural features of the muscle samples more clearly. For quantitative analysis, the multispectral Mueller matrix transformation (MMT) parameters are calculated to characterize the microstructural variations during the rigor mortis and proteolysis processes of the skeletal muscle tissue samples. The experimental results indicate that the multispectral MMT parameters can be used to judge different physiological stages for bovine skeletal muscle tissues in 24 hours, and combining with the multispectral technique, the Mueller matrix polarimetry and FDH analysis can monitor the microstructural variation features of skeletal muscle samples. The techniques may be used for quick assessment and quantitative monitoring of meat qualities in food industry.

  1. Measurement of Local Partial Pressure of Oxygen in the Brain Tissue under Normoxia and Epilepsy with Phosphorescence Lifetime Microscopy

    Science.gov (United States)

    Zhang, Cong; Bélanger, Samuel; Pouliot, Philippe; Lesage, Frédéric

    2015-01-01

    In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported. When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures. Investigating epileptic events, we characterized the spatio-temporal distribution of the "initial dip" in pO2 near the probe injection site and along nearby arterioles. Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure. PMID:26305777

  2. Measurement of Local Partial Pressure of Oxygen in the Brain Tissue under Normoxia and Epilepsy with Phosphorescence Lifetime Microscopy.

    Science.gov (United States)

    Zhang, Cong; Bélanger, Samuel; Pouliot, Philippe; Lesage, Frédéric

    2015-01-01

    In this work a method for measuring brain oxygen partial pressure with confocal phosphorescence lifetime microscopy system is reported. When used in conjunction with a dendritic phosphorescent probe, Oxyphor G4, this system enabled minimally invasive measurements of oxygen partial pressure (pO2) in cerebral tissue with high spatial and temporal resolution during 4-AP induced epileptic seizures. Investigating epileptic events, we characterized the spatio-temporal distribution of the "initial dip" in pO2 near the probe injection site and along nearby arterioles. Our results reveal a correlation between the percent change in the pO2 signal during the "initial dip" and the duration of seizure-like activity, which can help localize the epileptic focus and predict the length of seizure.

  3. Spontaneous calcium waves in Bergman glia increase with age and hypoxia and may reduce tissue oxygen

    DEFF Research Database (Denmark)

    Mathiesen, Claus; Brazhe, Alexey; Thomsen, Kirsten Joan

    2013-01-01

    Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen sa...... activity during aging, as well as low resting brain oxygen tension, suggests a relationship between glial waves, brain energy homeostasis, and pathology.......Glial calcium (Ca(2+)) waves constitute a means to spread signals between glial cells and to neighboring neurons and blood vessels. These waves occur spontaneously in Bergmann glia (BG) of the mouse cerebellar cortex in vivo. Here, we tested three hypotheses: (1) aging and reduced blood oxygen...... saturation alters wave activity; (2) glial Ca(2+) waves change cerebral oxygen metabolism; and (3) neuronal and glial wave activity is correlated. We used two-photon microscopy in the cerebellar cortexes of adult (8- to 15-week-old) and aging (48- to 80-week-old) ketamine-anesthetized mice after bolus...

  4. Influence of exercise duration on cardiorespiratory responses, energy cost and tissue oxygenation within a 6 hour treadmill run.

    Science.gov (United States)

    Kerhervé, Hugo A; McLean, Scott; Birkenhead, Karen; Parr, David; Solomon, Colin

    2017-01-01

    The physiological mechanisms for alterations in oxygen utilization ([Formula: see text]) and the energy cost of running ( C r ) during prolonged running are not completely understood, and could be linked with alterations in muscle and cerebral tissue oxygenation. Eight trained ultramarathon runners (three women; mean ± SD; age 37 ± 7 yr; maximum [Formula: see text] 60 ± 15 mL min -1  kg -1 ) completed a 6 hr treadmill run (6TR), which consisted of four modules, including periods of moderate (3 min at 10 km h -1 , 10-CR) and heavy exercise intensities (6 min at 70% of maximum [Formula: see text], HILL), separated by three, 100 min periods of self-paced running (SP). We measured [Formula: see text], minute ventilation ([Formula: see text]), ventilatory efficiency ([Formula: see text]), respiratory exchange ratio (RER), C r , muscle and cerebral tissue saturation index (TSI) during the modules, and heart rate (HR) and perceived exertion (RPE) during the modules and SP. Participants ran 58.3 ± 10.5 km during 6TR. Speed decreased and HR and RPE increased during SP. Across the modules, HR and [Formula: see text] increased (10-CR), and RER decreased (10-CR and HILL). There were no significant changes in [Formula: see text], [Formula: see text], C r , TSI and RPE across the modules. In the context of positive pacing (decreasing speed), increased cardiac drift and perceived exertion over the 6TR, we observed increased RER and increased HR at moderate and heavy exercise intensity, increased [Formula: see text] at moderate intensity, and no effect of exercise duration on ventilatory efficiency, energy cost of running and tissue oxygenation.

  5. Assessment of tissue oxygen saturation during a vascular occlusion test using near-infrared spectroscopy: the role of probe spacing and measurement site studied in healthy volunteers

    NARCIS (Netherlands)

    Bezemer, R.; Lima, A.; Myers, D.; Klijn, E.; Heger, M.; Goedhart, P.T.; Bakker, J.; Ince, C.

    2009-01-01

    INTRODUCTION: To assess potential metabolic and microcirculatory alterations in critically ill patients, near-infrared spectroscopy (NIRS) has been used, in combination with a vascular occlusion test (VOT), for the non-invasive measurement of tissue oxygen saturation (StO2), oxygen consumption, and

  6. Monitoring hemodynamics and oxygenation of the kidney in rats by a combined near-infrared spectroscopy and invasive probe approach

    Science.gov (United States)

    Grosenick, Dirk; Cantow, Kathleen; Arakelyan, Karen; Wabnitz, Heidrun; Flemming, Bert; Skalweit, Angela; Ladwig, Mechthild; Macdonald, Rainer; Niendorf, Thoralf; Seeliger, Erdmann

    2015-07-01

    We have developed a hybrid approach to investigate the dynamics of perfusion and oxygenation in the kidney of rats under pathophysiologically relevant conditions. Our approach combines near-infrared spectroscopy to quantify hemoglobin concentration and oxygen saturation in the renal cortex, and an invasive probe method for measuring total renal blood flow by an ultrasonic probe, perfusion by laser-Doppler fluxmetry, and tissue oxygen tension via fluorescence quenching. Hemoglobin concentration and oxygen saturation were determined from experimental data by a Monte Carlo model. The hybrid approach was applied to investigate and compare temporal changes during several types of interventions such as arterial and venous occlusions, as well as hyperoxia, hypoxia and hypercapnia induced by different mixtures of the inspired gas. The approach was also applied to study the effects of the x-ray contrast medium iodixanol on the kidney.

  7. Imaging of oxygenation in 3D tissue models with multi-modal phosphorescent probes

    Science.gov (United States)

    Papkovsky, Dmitri B.; Dmitriev, Ruslan I.; Borisov, Sergei

    2015-03-01

    Cell-penetrating phosphorescence based probes allow real-time, high-resolution imaging of O2 concentration in respiring cells and 3D tissue models. We have developed a panel of such probes, small molecule and nanoparticle structures, which have different spectral characteristics, cell penetrating and tissue staining behavior. The probes are compatible with conventional live cell imaging platforms and can be used in different detection modalities, including ratiometric intensity and PLIM (Phosphorescence Lifetime IMaging) under one- or two-photon excitation. Analytical performance of these probes and utility of the O2 imaging method have been demonstrated with different types of samples: 2D cell cultures, multi-cellular spheroids from cancer cell lines and primary neurons, excised slices from mouse brain, colon and bladder tissue, and live animals. They are particularly useful for hypoxia research, ex-vivo studies of tissue physiology, cell metabolism, cancer, inflammation, and multiplexing with many conventional fluorophors and markers of cellular function.

  8. Real-time monitoring of specific oxygen uptake rates of embryonic stem cells in a microfluidic cell culture device.

    Science.gov (United States)

    Super, Alexandre; Jaccard, Nicolas; Cardoso Marques, Marco Paulo; Macown, Rhys Jarred; Griffin, Lewis Donald; Veraitch, Farlan Singh; Szita, Nicolas

    2016-09-01

    Oxygen plays a key role in stem cell biology as a signaling molecule and as an indicator of cell energy metabolism. Quantification of cellular oxygen kinetics, i.e. the determination of specific oxygen uptake rates (sOURs), is routinely used to understand metabolic shifts. However current methods to determine sOUR in adherent cell cultures rely on cell sampling, which impacts on cellular phenotype. We present real-time monitoring of cell growth from phase contrast microscopy images, and of respiration using optical sensors for dissolved oxygen. Time-course data for bulk and peri-cellular oxygen concentrations obtained for Chinese hamster ovary (CHO) and mouse embryonic stem cell (mESCs) cultures successfully demonstrated this non-invasive and label-free approach. Additionally, we confirmed non-invasive detection of cellular responses to rapidly changing culture conditions by exposing the cells to mitochondrial inhibiting and uncoupling agents. For the CHO and mESCs, sOUR values between 8 and 60 amol cell(-1) s(-1) , and 5 and 35 amol cell(-1) s(-1) were obtained, respectively. These values compare favorably with literature data. The capability to monitor oxygen tensions, cell growth, and sOUR, of adherent stem cell cultures, non-invasively and in real time, will be of significant benefit for future studies in stem cell biology and stem cell-based therapies. © 2016 The Authors. Biotechnology Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Hypoxyradiotherapy: lack of experimental evidence for a preferential radioprotective effect on normal versus tumor tissue as shown by direct oxygenation measurements in experimental sarcomas

    International Nuclear Information System (INIS)

    Kelleher, Debra K.; Thews, Oliver; Vaupel, Peter

    1997-01-01

    Aim: In order to investigate possible pathophysiological mechanisms underlying the postulated preferential protective effect of hypoxia on normal tissue during radiotherapy, the impact of acute respiratory hypoxia (8.2% O 2 + 91.8% N 2 ) on tissue oxygenation was assessed. Methods: Tumor and normal tissue oxygenation was directly determined using O 2 -sensitive electrodes in two experimental rat tumors (DS and Yoshida sarcomas) and in the normal subcutis of the hind foot dorsum. Results: During respiratory hypoxia, arterial blood O 2 tension (pO 2 ), oxyhemoglobin saturation and mean arterial blood pressure decreased. Changes in the arterial blood gas status were accompanied by a reflex hyperventilation leading to hypocapnia and respiratory alkalosis. In the subcutis, tissue oxygenation worsened during acute hypoxia, with decreases in the mean and median pO 2 . Significant increases in the hypoxic fractions were, however, not seen. In tumor tissues, oxygenation also worsened upon hypoxic hypoxia with significant decreases in the mean and median pO 2 and increases in the size of the hypoxic fractions for both sarcomas. Conclusion: These results suggest that during respiratory hypoxia, radiobiologically relevant reductions in the oxygenation (and a subsequent selective radioprotection) of normal tissue may not be achieved. In addition, in the tumor models studied, a worsening of tumor oxygenation was seen which could result in an increased radioresistance

  10. Comparison of cerebral tissue oxygenation values in full term and preterm newborns by the simultaneous use of two near-infrared spectroscopy devices: an absolute and a relative trending oximeter

    Science.gov (United States)

    Szczapa, Tomasz; Karpiński, Łukasz; Moczko, Jerzy; Weindling, Michael; Kornacka, Alicja; Wróblewska, Katarzyna; Adamczak, Aleksandra; Jopek, Aleksandra; Chojnacka, Karolina; Gadzinowski, Janusz

    2013-08-01

    The aim of this study is to compare a two-wavelength light emitting diode-based tissue oximeter (INVOS), which is designed to show trends in tissue oxygenation, with a four-wavelength laser-based oximeter (FORE-SIGHT), designed to deliver absolute values of tissue oxygenation. Simultaneous values of cerebral tissue oxygenation (StO2) are measured using both devices in 15 term and 15 preterm clinically stable newborns on the first and third day of life. Values are recorded simultaneously in two periods between which oximeter sensor positions are switched to the contralateral side. Agreement between StO2 values before and after the change of sensor position is analyzed. We find that mean cerebral StO2 values are similar between devices for term and preterm babies, but INVOS shows StO2 values spread over a wider range, with wider standard deviations than shown by the FORE-SIGHT. There is relatively good agreement with a bias up to 3.5% and limits of agreement up to 11.8%. Measurements from each side of the forehead show better repeatability for the FORE-SIGHT monitor. We conclude that performance of the two devices is probably acceptable for clinical purposes. Both performed sufficiently well, but the use of FORE-SIGHT may be associated with tighter range and better repeatability of data.

  11. [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

  12. 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

  13. Monitoring sinew contraction during formation of tissue-engineered fibrin-based ligament constructs.

    Science.gov (United States)

    Paxton, Jennifer Z; Wudebwe, Uchena N G; Wang, Anqi; Woods, Daniel; Grover, Liam M

    2012-08-01

    The ability to study the gross morphological changes occurring during tissue formation is vital to producing tissue-engineered structures of clinically relevant dimensions in vitro. Here, we have used nondestructive methods of digital imaging and optical coherence tomography to monitor the early-stage formation and subsequent maturation of fibrin-based tissue-engineered ligament constructs. In addition, the effect of supplementation with essential promoters of collagen synthesis, ascorbic acid (AA) and proline (P), has been assessed. Contraction of the cell-seeded fibrin gel occurs unevenly within the first 5 days of culture around two fixed anchor points before forming a longitudinal ligament-like construct. AA+P supplementation accelerates gel contraction in the maturation phase of development, producing ligament-like constructs with a higher collagen content and distinct morphology to that of unsupplemented constructs. These studies highlight the importance of being able to control the methods of tissue formation and maturation in vitro to enable the production of tissue-engineered constructs with suitable replacement tissue characteristics for repair of clinical soft-tissue injuries.

  14. Two-photon high-resolution measurement of partial pressure of oxygen in cerebral vasculature and tissue

    Science.gov (United States)

    Sakadžić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A.; Mandeville, Emiri T.; Srinivasan, Vivek J.; Arai, Ken; Ruvinskaya, Svetlana; Devor, Anna; Lo, Eng H.; Vinogradov, Sergei A.; Boas, David A.

    2010-01-01

    The ability to measure oxygen partial pressure (pO2) with high temporal and spatial resolution in three dimensions is crucial for understanding oxygen delivery and consumption in normal and diseased brain. Among existing pO2 measurement methods, phosphorescence quenching is optimally suited for the task. However, previous attempts to couple phosphorescence with two-photon laser scanning microscopy have faced substantial difficulties because of extremely low two-photon absorption cross-sections of conventional phosphorescent probes. Here, we report the first practical in vivo two-photon high-resolution pO2 measurements in small rodents’ cortical microvasculature and tissue, made possible by combining an optimized imaging system with a two-photon-enhanced phosphorescent nanoprobe. The method features a measurement depth of up to 250 µm, sub-second temporal resolution and requires low probe concentration. Most importantly, the properties of the probe allowed for the first direct high-resolution measurement of cortical extravascular (tissue) pO2, opening numerous possibilities for functional metabolic brain studies. PMID:20693997

  15. Two-photon high-resolution measurement of partial pressure of oxygen in cerebral vasculature and tissue.

    Science.gov (United States)

    Sakadzić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A; Mandeville, Emiri T; Srinivasan, Vivek J; Arai, Ken; Ruvinskaya, Svetlana; Devor, Anna; Lo, Eng H; Vinogradov, Sergei A; Boas, David A

    2010-09-01

    Measurements of oxygen partial pressure (pO(2)) with high temporal and spatial resolution in three dimensions is crucial for understanding oxygen delivery and consumption in normal and diseased brain. Among existing pO(2) measurement methods, phosphorescence quenching is optimally suited for the task. However, previous attempts to couple phosphorescence with two-photon laser scanning microscopy have faced substantial difficulties because of extremely low two-photon absorption cross-sections of conventional phosphorescent probes. Here we report to our knowledge the first practical in vivo two-photon high-resolution pO(2) measurements in small rodents' cortical microvasculature and tissue, made possible by combining an optimized imaging system with a two-photon-enhanced phosphorescent nanoprobe. The method features a measurement depth of up to 250 microm, sub-second temporal resolution and requires low probe concentration. The properties of the probe allowed for direct high-resolution measurement of cortical extravascular (tissue) pO(2), opening many possibilities for functional metabolic brain studies.

  16. The Effects of Walking or Walking-with-Poles Training on Tissue Oxygenation in Patients with Peripheral Arterial Disease

    Directory of Open Access Journals (Sweden)

    Eileen G. Collins

    2012-01-01

    Full Text Available This randomized trial proposed to determine if there were differences in calf muscle StO2 parameters in patients before and after 12 weeks of a traditional walking or walking-with-poles exercise program. Data were collected on 85 patients who were randomized to a traditional walking program ( or walking-with-poles program ( of exercise training. Patients walked for 3 times weekly for 12 weeks. Seventy-one patients completed both the baseline and the 12-week follow-up progressive treadmill tests ( traditional walking and walking-with-poles. Using the near-infrared spectroscopy measures, StO2 was measured prior to, during, and after exercise. At baseline, calf muscle oxygenation decreased from % prior to the treadmill test to % at peak exercise. The time elapsed prior to reaching nadir StO2 values increased more in the traditional walking group when compared to the walking-with-poles group. Likewise, absolute walking time increased more in the traditional walking group than in the walking-with-poles group. Tissue oxygenation decline during treadmill testing was less for patients assigned to a 12-week traditional walking program when compared to those assigned to a 12-week walking-with-poles program. In conclusion, the 12-week traditional walking program was superior to walking-with-poles in improving tissue deoxygenation in patients with PAD.

  17. New principle for measuring arterial blood oxygenation, enabling motion-robust remote monitoring.

    Science.gov (United States)

    van Gastel, Mark; Stuijk, Sander; de Haan, Gerard

    2016-12-07

    Finger-oximeters are ubiquitously used for patient monitoring in hospitals worldwide. Recently, remote measurement of arterial blood oxygenation (SpO 2 ) with a camera has been demonstrated. Both contact and remote measurements, however, require the subject to remain static for accurate SpO 2 values. This is due to the use of the common ratio-of-ratios measurement principle that measures the relative pulsatility at different wavelengths. Since the amplitudes are small, they are easily corrupted by motion-induced variations. We introduce a new principle that allows accurate remote measurements even during significant subject motion. We demonstrate the main advantage of the principle, i.e. that the optimal signature remains the same even when the SNR of the PPG signal drops significantly due to motion or limited measurement area. The evaluation uses recordings with breath-holding events, which induce hypoxemia in healthy moving subjects. The events lead to clinically relevant SpO 2 levels in the range 80-100%. The new principle is shown to greatly outperform current remote ratio-of-ratios based methods. The mean-absolute SpO 2 -error (MAE) is about 2 percentage-points during head movements, where the benchmark method shows a MAE of 24 percentage-points. Consequently, we claim ours to be the first method to reliably measure SpO 2 remotely during significant subject motion.

  18. Early resuscitation with polymerized bovine hemoglobin reverses acidosis, but not peripheral tissue oxygenation, in a severe hamster shock model.

    Science.gov (United States)

    Wettstein, Reto; Tsai, Amy G; Harder, Yves; Erni, Dominique; Intaglietta, Marcos

    2006-11-01

    Awake hamsters equipped with the dorsal window chamber preparation were subjected to hemorrhage of 50% of the estimated blood volume. Initial resuscitation (25% of estimated blood volume) with polymerized bovine hemoglobin (PBH) or 10% hydroxyethyl starch (HES) occurred in concert with an equivolumetric bleeding to simulate the early, prehospital setting (exchange transfusion). Resuscitation (25% of estimated blood volume) without bleeding was performed with PBH, HES, or autologous red blood cells (HES-RBCs). Peripheral microcirculation, tissue oxygenation, and systemic hemodynamic and blood gas parameters were assessed. After exchange transfusion, base deficit was -8.6 +/- 3.7 mmol/L (PBH) and -5.1 +/- 5.3 mmol/L (HES) (not significant). Functional capillary density was 17% +/- 6% of baseline (PBH) and 31% +/- 11% (HES) (P < 0.05) and arteriolar diameter 73% +/- 3% of baseline (PBH) and 90% + 5% (HES) (P < 0.01). At the end, hemoglobin levels were 3.7 +/- 0.3 g/dL with HES, 8.2 +/- 0.6 g/dL with PBH, and 10.4 +/- 0.8 g/dL with HES-RBCs (P < 0.01 HES vs. PBH and HES-RBCs, P < 0.05 PBH vs. HES-RBCs). Base excess was restored to baseline with PBH and HES-RBCs, but not with HES (P < 0.05). Functional capillary density was 46% +/- 5% of baseline (PBH), 62% + 20% (HES-RBCs), and 36% +/- 19% (HES) (P < 0.01 HES-RBCs vs. HES). Peripheral oxygen delivery and consumption was highest with HES-RBCs, followed by PBH (P < 0.05 HES-RBCs vs. PBH, P < 0.01 HES-RBCs and PBH vs. HES). In conclusion, the PBH led to a correction of base deficit comparable to blood transfusion. However, oxygenation of the peripheral tissue was inferior with PBH. This was attributed to its negative impact on the peripheral microcirculation caused by arteriolar vasoconstriction.

  19. Cerebral tissue oxygenation index and superior vena cava blood flow in the very low birth weight infant.

    LENUS (Irish Health Repository)

    Moran, M

    2012-02-01

    BACKGROUND: Superior vena cava (SVC) flow assesses blood flow from the upper body, including the brain. Near infrared spectroscopy (NIRS) provides information on brain perfusion and oxygenation. AIM: To assess the relationship between cerebral tissue oxygenation index (cTOI) and cardiac output measures in the very low birth weight (VLBW) infant in the first day of life. METHODS: A prospective observational cohort study. Neonates with birth weight less than 1500 g (VLBW) were eligible for enrollment. Newborns with congenital heart disease, major congenital malformations and greater than Papile grade1 Intraventricular Haemorrhage on day 1 of life were excluded. Echocardiographic evaluation of SVC flow was performed in the first 24 h of life. Low SVC flow states were defined as a flow less than 40 mL\\/kg\\/min. cTOI was measured using NIRO 200 Hamamatsu. RESULTS: Twenty-seven VLBW neonates had both echocardiography and NIRS performed. The median (range) gestation was 29\\/40 (25 + 3 to 31 + 5 weeks) and median birth weight was 1.2 kg (0.57-1.48 kg). The mean (SD) TOI was 68.1 (7.9)%. The mean (SD) SVC flow was 70.36(39.5) mLs\\/kg\\/min. The correlation coefficient of cerebral tissue oxygenation and SVC flow was r = 0.53, p-value 0.005. There was a poor correlation between right and left ventricular output and cTOI which is not surprising considering the influence of intra- and extracardiac shunts. CONCLUSION: There is a positive relationship between cerebral TOI values and SVC flow in the very low birth infant on day one of life.

  20. Mercury monitoring in fish using a non-lethal tissue biopsy method

    Science.gov (United States)

    Ackerson, J; Schmitt, Christopher J.; McKee, J; Brumbaugh, W. G.

    2010-01-01

    The occurrence of mercury in fish is well-known and often occurs at levels that warrant restricted consumption by sensitive human populations. Because of this, local wildlife and health agencies have developed monitoring programs to identify the magnitude of fish contamination and changes through time. Monitoring mercury levels in fish typically requires killing fish for removal of a fillet. Recently, researchers have proposed the use of a non-lethal tissue biopsy plug method as a surrogate for analysis of the entire fillet.

  1. The human ear canal: investigation of its suitability for monitoring photoplethysmographs and arterial oxygen saturation

    International Nuclear Information System (INIS)

    Budidha, K; Kyriacou, P A

    2014-01-01

    For the last two decades, pulse oximetry has been used as a standard procedure for monitoring arterial oxygen saturation (SpO 2 ). However, SpO 2 measurements made from extremities such as the finger, ear lobe and toes become susceptible to inaccuracies when peripheral perfusion is compromised. To overcome these limitations, the external auditory canal has been proposed as an alternative monitoring site for estimating SpO 2 , on the hypothesis that this central site will be better perfused. Therefore, a dual wavelength optoelectronic probe along with a processing system was developed to investigate the suitability of measuring photoplethysmographic (PPG) signals and SpO 2 in the human auditory canal. A pilot study was carried out in 15 healthy volunteers to validate the feasibility of measuring PPGs and SpO 2  from the ear canal (EC), and comparative studies were performed by acquiring the same signals from the left index finger (LIF) and the right index finger (RIF) in conditions of induced peripheral vasoconstriction (right hand immersion in ice water). Good quality baseline PPG signals with high signal-to-noise ratio were obtained from the EC, the LIF and the RIF sensors. During the ice water immersion, significant differences in the amplitude of the red and infrared PPG signals were observed from the RIF and the LIF sensors. The average drop in amplitude of red and infrared PPG signals from the RIF was 52.7% and 58.3%. Similarly, the LIF PPG signal amplitudes have reduced by 47.52% and 46.8% respectively. In contrast, no significant changes were seen in the red and infrared EC PPG amplitude measurements, which changed by +2.5% and −1.2% respectively. The RIF and LIF pulse oximeters have failed to estimate accurate SpO 2  in seven and four volunteers respectively, while the EC pulse oximeter has only failed in one volunteer. These results suggest that the EC may be a suitable site for reliable monitoring of PPGs and SpO 2 s even in the presence of

  2. The importance of bilateral monitoring of cerebral oxygenation (NIRS): Clinical case of asymmetry during cardiopulmonary bypass secondary to previous cerebral infarction.

    Science.gov (United States)

    Matcan, S; Sanabria Carretero, P; Gómez Rojo, M; Castro Parga, L; Reinoso-Barbero, F

    2018-03-01

    Cerebral oximetry based on near infrared spectroscopy (NIRS) technology is used to determine cerebral tissue oxygenation. We hereby present the clinical case of a 12-month old child with right hemiparesis secondary to prior left middle cerebral artery stroke 8 months ago. The child underwent surgical enlargement of the right ventricular outflow tract (RVOT) with cardiopulmonary bypass. During cardiopulmonary bypass, asymmetric NIRS results were detected between both hemispheres. The utilization of multimodal neuromonitoring (NIRS-BIS) allowed acting on both perfusion pressure and anesthetic depth to balance out the supply and demand of cerebral oxygen consumption. No new neurological sequelae were observed postoperatively. We consider bilateral NIRS monitoring necessary in order to detect asymmetries between cerebral hemispheres. Although asymmetries were not present at baseline, they can arise intraoperatively and its monitoring thus allows the detection and treatment of cerebral ischemia-hypoxia in the healthy hemisphere, which if undetected and untreated would lead to additional neurological damage. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Effects of compression injury on brain mitochondrial and tissue viability evaluated by a multiparametric monitoring system

    Science.gov (United States)

    Barbiro-Michaely, Efrat; Bachbut, Galit; Mayevsky, Avraham

    2008-02-01

    Neurosurgical procedures involve brain compression created by retractors. Although it is clear that retractors are causing damage to the brain tissue, the pathophysiology of the retraction was not investigated in details. In the present study we used the multiparametric monitoring approach for real time evaluation of mitochondrial function, hemodynamic, ionic and electrical activities monitored contralaterally to the retractor placement on the brain. The aims of the study were to test the effects of retractor size and severity of the compression on the degree of damage to the cerebral tissue. A special probe was lowered towards the cerebral cortex, (2mm and 4mm in depth) using a micromanipulator. Compression lasted for 30 minutes, than the retractor was elevated back to its initial position and monitoring continued for two hours. Additionally, two sizes of retractors were used 6mm and 3mm in diameter, the 3mm retractor included an intracranial pressure (ICP) probe. The results show that the combination of a large retractor with the depth of 4mm yielded high mortality rate (62%) of the rats while the use of a smaller retractor decreased significantly the percentage of mortality. Also, compression to the depth of 4mm increased tissue injury as compared to 2mm depth. In conclusion, the present study raises the importance and significance of multiparametric monitoring, and not only ICP and cerebral blood flow of the areas nearby the retractor position and not only the retraction site, as well as the effect of the retractor size on the damage induced to the cerebral tissue.

  4. Continuous tissue glucose monitoring correlates with measurement of intermittent capillary glucose in patients with distributive shock.

    Science.gov (United States)

    Ballesteros, D; Martínez, Ó; Blancas Gómez-Casero, R; Martín Parra, C; López Matamala, B; Estébanez, B; Chana, M

    2015-10-01

    Intermittent glycemic measurements in patients admitted to the intensive care unit (ICU) can result in episodes of severe hypoglycemia or in a poor control of glycemia range. We designed a study to assess accuracy and reliability of continuous monitoring of tissue glucose for patients with distributive shock. Consecutive patients admitted to the ICU with a diagnosis of distributive shock and the need of insulin infusion for glycemic control were included in the study. These patients were implanted a Continuous Glucose Control Monitoring System (CGMS) with the sensor inserted subcutaneously into the abdominal wall. CGMS values were recorded every 5min. Capillary glucose (CG) was monitored for adjusting insulin perfusion according to the ICU protocol. Correlation between both methods was assessed. A total of 11,673 CGMS and 348 CG values were recorded. In five patients, CGMS failed to detect tissue glucose. A glucose value <3.33mmol/l (<60mg/dl) was observed in 3.6% of CGMS and in 0.29% CG values. 295 pairs of measurements were included in the statistical analysis for correlation assessment. The intraclass correlation coefficient was 0.706. The Pearson correlation coefficient was 0.71 (p<0.0001, 95% CI 0.65-0.76). The mean of differences between both measurement methods was 0.22mmol/l (3.98mg/dl) (95% CI 0.66-7.31). When the Continuous Glucose Control Monitoring System (CGMS) is able to obtain data (75% of the patients), there is correlation between the values obtained by this method and capillary blood glucose in patients with distributive shock. CGMS can detect more episodes of glycemic excursions outside the normal range than intermittent capillary glucose monitoring. Variables that may impair glucose metabolism and peripheral soft tissues perfusion could impair CGMS measurements. Copyright © 2014 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

  5. [Observation on changes of oxygen partial pressure in the deep tissues along the large intestine meridian during acupuncture in healthy subjects].

    Science.gov (United States)

    Chen, Ming; Hu, Xiang-long; Wu, Zu-xing

    2010-06-01

    To observe changes of the partial oxygen pressure in the deep tissues along the Large Intestine Meridian (LIM) during acupuncture stimulation, so as to reveal the characteristics of energy metabolism in the tissues along the LIM. Thirty-one healthy volunteer subjects were enlisted in the present study. Partial oxygen pressure (POP) in the tissues (at a depth of about 1.5 cm) of acupoints Binao (LI 14), Shouwuli (LI 13), Shousanli (LI 10), 2 non-acupoints [the midpoints between Quchi (LI 11) and LI 14, and between Yangxi (LI 5) and LI 11) of the LIM, and 10 non-meridian points, 1.5-2.0 cm lateral and medial to each of the tested points of the LIM was detected before, during and after electroacupuncture (EA) stimulation of Hegu (LI 4) by using a tissue oxygen tension needle-like sensor. In normal condition, the POP values in the deep tissues along the LIM were significantly higher than those of the non-meridian control points on its bilateral sides. During and after EA of Hegu (LI 4), the POP levels decreased significantly in the deep tissues along the LIM in comparison with pre-EA (P 0.05). POP is significantly higher in the deep tissues along the LIM of healthy subjects under normal conditions, which can be downregulated by EA of Hegu (LI 4), suggesting an increase of both the utilization rate of oxygen and energy metabolism after EA.

  6. In vivo evidence of methamphetamine induced attenuation of brain tissue oxygenation as measured by EPR oximetry

    International Nuclear Information System (INIS)

    Weaver, John; Yang, Yirong; Purvis, Rebecca; Weatherwax, Theodore; Rosen, Gerald M.; Liu, Ke Jian

    2014-01-01

    Abuse of methamphetamine (METH) is a major and significant societal problem in the US, as a number of studies have suggested that METH is associated with increased cerebrovascular events, hemorrhage or vasospasm. Although cellular and molecular mechanisms involved in METH-induced toxicity are not completely understood, changes in brain O 2 may play an important role and contribute to METH-induced neurotoxicity including dopaminergic receptor degradation. Given that O 2 is the terminal electron acceptor for many enzymes that are important in brain function, the impact of METH on brain tissue pO 2 in vivo remains largely uncharacterized. This study investigated striatal tissue pO 2 changes in male C57BL/6 mice (16–20 g) following METH administration using EPR oximetry, a highly sensitive modality to measure pO 2 in vivo, in situ and in real time. We demonstrate that 20 min after a single injection of METH (8 mg/kg i.v.), the striatal pO 2 was reduced to 81% of the pretreatment level and exposure to METH for 3 consecutive days further attenuated striatal pO 2 to 64%. More importantly, pO 2 did not recover fully to control levels even 24 h after administration of a single dose of METH and continual exposure to METH exacerbates the condition. We also show a reduction in cerebral blood flow associated with a decreased brain pO 2 indicating an ischemic condition. Our findings suggests that administration of METH can attenuate brain tissue pO 2 , which may lead to hypoxic insult, thus a risk factor for METH-induced brain injury and the development of stroke in young adults. - Highlights: • Explored striatal tissue pO 2 in vivo after METH administration by EPR oximetry. • pO 2 was reduced by 81% after a single dose and 64% after 3 consecutive daily doses. • pO 2 did not recover fully to control levels even 24 h after a single dose. • Decrease in brain tissue pO 2 may be associated with a decrease in CBF. • Administration of methamphetamine may lead to hypoxic

  7. In vivo evidence of methamphetamine induced attenuation of brain tissue oxygenation as measured by EPR oximetry

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, John, E-mail: jmweaver@salud.unm.edu [Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Yang, Yirong [Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Purvis, Rebecca [Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Weatherwax, Theodore [Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Rosen, Gerald M. [Center for Biomedical Engineering and Technology, University of Maryland, Baltimore, MD 21201 (United States); Center for EPR Imaging In Vivo Physiology, University of Maryland, Baltimore, MD 21201 (United States); Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201 (United States); Liu, Ke Jian [Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States); Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM 87131 (United States)

    2014-03-01

    Abuse of methamphetamine (METH) is a major and significant societal problem in the US, as a number of studies have suggested that METH is associated with increased cerebrovascular events, hemorrhage or vasospasm. Although cellular and molecular mechanisms involved in METH-induced toxicity are not completely understood, changes in brain O{sub 2} may play an important role and contribute to METH-induced neurotoxicity including dopaminergic receptor degradation. Given that O{sub 2} is the terminal electron acceptor for many enzymes that are important in brain function, the impact of METH on brain tissue pO{sub 2}in vivo remains largely uncharacterized. This study investigated striatal tissue pO{sub 2} changes in male C57BL/6 mice (16–20 g) following METH administration using EPR oximetry, a highly sensitive modality to measure pO{sub 2}in vivo, in situ and in real time. We demonstrate that 20 min after a single injection of METH (8 mg/kg i.v.), the striatal pO{sub 2} was reduced to 81% of the pretreatment level and exposure to METH for 3 consecutive days further attenuated striatal pO{sub 2} to 64%. More importantly, pO{sub 2} did not recover fully to control levels even 24 h after administration of a single dose of METH and continual exposure to METH exacerbates the condition. We also show a reduction in cerebral blood flow associated with a decreased brain pO{sub 2} indicating an ischemic condition. Our findings suggests that administration of METH can attenuate brain tissue pO{sub 2}, which may lead to hypoxic insult, thus a risk factor for METH-induced brain injury and the development of stroke in young adults. - Highlights: • Explored striatal tissue pO{sub 2}in vivo after METH administration by EPR oximetry. • pO{sub 2} was reduced by 81% after a single dose and 64% after 3 consecutive daily doses. • pO{sub 2} did not recover fully to control levels even 24 h after a single dose. • Decrease in brain tissue pO{sub 2} may be associated with a decrease in

  8. Acute effects of nicotine and smoking on blood flow, tissue oxygen, and aerobe metabolism of the skin and subcutis

    DEFF Research Database (Denmark)

    Sørensen, Lars Tue; Jørgensen, Stig; Petersen, Lars J

    2009-01-01

    BACKGROUND: Nicotine released from tobacco smoke causing reduction in blood flow has been suggested as causative for postoperative wound complications in smokers, but the mechanism remains unknown. MATERIALS AND METHODS: In eight healthy male smokers and eight ex-smokers, the cutaneous and subcut......BACKGROUND: Nicotine released from tobacco smoke causing reduction in blood flow has been suggested as causative for postoperative wound complications in smokers, but the mechanism remains unknown. MATERIALS AND METHODS: In eight healthy male smokers and eight ex-smokers, the cutaneous...... and subcutaneous blood flow (QBF, SqBF) was assessed by Laser Doppler and 133Xe clearance. Tissue oxygen tension (TO(2)) was measured by a LICOX O(2)-electrode. Tissue glucose and lactate (Tgluc, Tlact) were assessed by microdialysis. The parameters were studied after intravenous infusion of 1.0 mg nicotine......, smoking of one cigarette, arterial occlusion, and reperfusion. RESULTS: Nicotine infusion decreased SqBF from 4.2 +/- 2.0 to 3.1 +/- 1.2 mL/100 g tissue/min (P

  9. Simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in humans and other animal models using a single light source

    Science.gov (United States)

    Dent, Paul; Tun, Sai Han; Fillioe, Seth; Deng, Bin; Satalin, Josh; Nieman, Gary; Wilcox, Kailyn; Searles, Quinn; Narsipur, Sri; Peterson, Charles M.; Goodisman, Jerry; Mostrom, James; Steinmann, Richard; Chaiken, J.

    2018-02-01

    We previously reported a new algorithm "PV[O]H" for continuous, noninvasive, in vivo monitoring of hematocrit changes in blood and have since shown its utility for monitoring in humans during 1) hemodialysis, 2) orthostatic perturbations and 3) during blood loss and fluid replacement in a rat model. We now show that the algorithm is sensitive to changes in hemoglobin oxygen saturation. We document the phenomenology of the effect and explain the effect using new results obtained from humans and rat models. The oxygen sensitivity derives from the differential absorption of autofluorescence originating in the static tissues by oxy and deoxy hemoglobin. Using this approach we show how to perform simultaneous, noninvasive, in vivo, continuous monitoring of hematocrit, vascular volume, hemoglobin oxygen saturation, pulse rate and breathing rate in mammals using a single light source. We suspect that monitoring of changes in this suite of vital signs can be provided with improved time response, sensitivity and precision compared to existing methodologies. Initial results also offer a more detailed glimpse into the systemic oxygen transport in the circulatory system of humans.

  10. Ascorbic acid metabolism in the organism under the lack of oxygen supply to the tissues

    Directory of Open Access Journals (Sweden)

    Sergiy Petrov

    2017-06-01

    Full Text Available The number and ratios of the metabolites of vitamin C - ascorbic, dehydroascorbic and diketogulonic acids were studied under the action of closed space hypoxia, acute blood loss and during sleep – the conditions associated with various oxygen saturation of the organism. It was found that in case of closed space hypoxia, the level of ascorbic and diketogulonic acid decreased with a simultaneous increase in the content of dehydroascorbic acid in the heart and brain. Acute blood loss resulted in decrease in the level of all metabolites of ascorbic acid. During sleep, the level of ascorbic acid metabolites increased. The ratio of vitamin-active metabolites to vitamin-inactive form of ascorbic acid in case of closed space hypoxia and acute blood loss decreased, and during sleep – it did not change significantly.

  11. Effects of hyperoxia on 18F-fluoro-misonidazole brain uptake and tissue oxygen tension following middle cerebral artery occlusion in rodents: Pilot studies.

    Directory of Open Access Journals (Sweden)

    Tim D Fryer

    Full Text Available Mapping brain hypoxia is a major goal for stroke diagnosis, pathophysiology and treatment monitoring. 18F-fluoro-misonidazole (FMISO positron emission tomography (PET is the gold standard hypoxia imaging method. Normobaric hyperoxia (NBO is a promising therapy in acute stroke. In this pilot study, we tested the straightforward hypothesis that NBO would markedly reduce FMISO uptake in ischemic brain in Wistar and spontaneously hypertensive rats (SHRs, two rat strains with distinct vulnerability to brain ischemia, mimicking clinical heterogeneity.Thirteen adult male rats were randomized to distal middle cerebral artery occlusion under either 30% O2 or 100% O2. FMISO was administered intravenously and PET data acquired dynamically for 3hrs, after which magnetic resonance imaging (MRI and tetrazolium chloride (TTC staining were carried out to map the ischemic lesion. Both FMISO tissue uptake at 2-3hrs and FMISO kinetic rate constants, determined based on previously published kinetic modelling, were obtained for the hypoxic area. In a separate group (n = 9, tissue oxygen partial pressure (PtO2 was measured in the ischemic tissue during both control and NBO conditions.As expected, the FMISO PET, MRI and TTC lesion volumes were much larger in SHRs than Wistar rats in both the control and NBO conditions. NBO did not appear to substantially reduce FMISO lesion size, nor affect the FMISO kinetic rate constants in either strain. Likewise, MRI and TTC lesion volumes were unaffected. The parallel study showed the expected increases in ischemic cortex PtO2 under NBO, although these were small in some SHRs with very low baseline PtO2.Despite small samples, the apparent lack of marked effects of NBO on FMISO uptake suggests that in permanent ischemia the cellular mechanisms underlying FMISO trapping in hypoxic cells may be disjointed from PtO2. Better understanding of FMISO trapping processes will be important for future applications of FMISO imaging.

  12. Influence of exercise duration on cardiorespiratory responses, energy cost and tissue oxygenation within a 6 hour treadmill run

    Directory of Open Access Journals (Sweden)

    Hugo A. Kerhervé

    2017-10-01

    Full Text Available Purpose The physiological mechanisms for alterations in oxygen utilization ( $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 and the energy cost of running (Cr during prolonged running are not completely understood, and could be linked with alterations in muscle and cerebral tissue oxygenation. Methods Eight trained ultramarathon runners (three women; mean ± SD; age 37 ± 7 yr; maximum $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 60 ± 15 mL min−1 kg−1 completed a 6 hr treadmill run (6TR, which consisted of four modules, including periods of moderate (3 min at 10 km h−1, 10-CR and heavy exercise intensities (6 min at 70% of maximum $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 , HILL, separated by three, 100 min periods of self-paced running (SP. We measured $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 , minute ventilation ( ${\\dot {\\mathrm{V }}}_{\\mathrm{E}}$ V ̇ E , ventilatory efficiency ( ${\\dot {\\mathrm{V }}}_{\\mathrm{E}}:\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ E : V ̇ O 2 , respiratory exchange ratio (RER, Cr, muscle and cerebral tissue saturation index (TSI during the modules, and heart rate (HR and perceived exertion (RPE during the modules and SP. Results Participants ran 58.3 ± 10.5 km during 6TR. Speed decreased and HR and RPE increased during SP. Across the modules, HR and $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 increased (10-CR, and RER decreased (10-CR and HILL. There were no significant changes in ${\\dot {\\mathrm{V }}}_{\\mathrm{E}}$ V ̇ E , ${\\dot {\\mathrm{V }}}_{\\mathrm{E}}:\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ E : V ̇ O 2 , Cr, TSI and RPE across the modules. Conclusions In the context of positive pacing (decreasing speed, increased cardiac drift and perceived exertion over the 6TR, we observed increased RER and increased HR at moderate and heavy exercise intensity, increased $\\dot {\\mathrm{V }}{\\mathrm{O}}_{2}$ V ̇ O 2 at moderate intensity, and no effect of

  13. In vivo evidence of methamphetamine induced attenuation of brain tissue oxygenation as measured by EPR oximetry

    Science.gov (United States)

    Weaver, John; Yang, Yirong; Purvis, Rebecca; Weatherwax, Theodore; Rosen, Gerald M.; Liu, Ke Jian

    2014-01-01

    Abuse of methamphetamine (METH) is a major and significant societal problem in the US, as a number of studies have suggested that METH is associated with increased cerebrovascular events, hemorrhage or vasospasm. Although cellular and molecular mechanisms involved in METH-induced toxicity are not completely understood, changes in brain O2 may play an important role and contribute to METH-induced neurotoxicity including dopaminergic receptor degradation. Given that O2 is the terminal electron acceptor for many enzymes that are important in brain function, the impact of METH on brain tissue pO2 in vivo remains largely uncharacterized. This study investigated striatal tissue pO2 changes in male C57BL/6 mice (16–20g) following METH administration using EPR oximetry, a highly sensitive modality to measure pO2 in vivo, in situ and in real time. We demonstrate that 20 min after a single injection of METH (8 mg/kg i.v.), the striatal pO2 was reduced to 81% of the pretreatment level and exposure to METH for 3 consecutive days further attenuated striatal pO2 to 64%. More importantly, pO2 did not recover fully to control levels even 24 hrs after administration of a single dose of METH. and continual exposure to METH exacerbates the condition. We also show a reduction in cerebral blood flow associated with a decreased brain pO2 indicating an ischemic condition. Our findings suggests that administration of METH can attenuate brain tissue pO2, which may lead to hypoxic insult, thus a risk factor for METH-induced brain injury and the development of stroke in young adults. PMID:24412707

  14. Importance of good manufacturing practices in microbiological monitoring in processing human tissues for transplant.

    Science.gov (United States)

    Pianigiani, Elisa; Ierardi, Francesca; Fimiani, Michele

    2013-12-01

    Skin allografts represent an important therapeutic resource in the treatment of severe skin loss. The risk associated with application of processed tissues in humans is very low, however, human material always carries the risk of disease transmission. To minimise the risk of contamination of grafts, processing is carried out in clean rooms where air quality is monitored. Procedures and quality control tests are performed to standardise the production process and to guarantee the final product for human use. Since we only validate and distribute aseptic tissues, we conducted a study to determine what type of quality controls for skin processing are the most suitable for detecting processing errors and intercurrent contamination, and for faithfully mapping the process without unduly increasing production costs. Two different methods for quality control were statistically compared using the Fisher exact test. On the basis of the current study we selected our quality control procedure based on pre- and post-processing tissue controls, operator and environmental controls. Evaluation of the predictability of our control methods showed that tissue control was the most reliable method of revealing microbial contamination of grafts. We obtained 100 % sensitivity by doubling tissue controls, while maintaining high specificity (77 %).

  15. Ovarian tissue cryopreservation by stepped vitrification and monitored by X-ray computed tomography.

    Science.gov (United States)

    Corral, Ariadna; Clavero, Macarena; Gallardo, Miguel; Balcerzyk, Marcin; Amorim, Christiani A; Parrado-Gallego, Ángel; Dolmans, Marie-Madeleine; Paulini, Fernanda; Morris, John; Risco, Ramón

    2018-04-01

    Ovarian tissue cryopreservation is, in most cases, the only fertility preservation option available for female patients soon to undergo gonadotoxic treatment. To date, cryopreservation of ovarian tissue has been carried out by both traditional slow freezing method and vitrification, but even with the best techniques, there is still a considerable loss of follicle viability. In this report, we investigated a stepped cryopreservation procedure which combines features of slow cooling and vitrification (hereafter called stepped vitrification). Bovine ovarian tissue was used as a tissue model. Stepwise increments of the Me 2 SO concentration coupled with stepwise drops-in temperature in a device specifically designed for this purpose and X-ray computed tomography were combined to investigate loading times at each step, by monitoring the attenuation of the radiation proportional to Me 2 SO permeation. Viability analysis was performed in warmed tissues by immunohistochemistry. Although further viability tests should be conducted after transplantation, preliminary results are very promising. Four protocols were explored. Two of them showed a poor permeation of the vitrification solution (P1 and P2). The other two (P3 and P4), with higher permeation, were studied in deeper detail. Out of these two protocols, P4, with a longer permeation time at -40 °C, showed the same histological integrity after warming as fresh controls. Copyright © 2018 Elsevier Inc. All rights reserved.

  16. Hydrogen generation monitoring and mass gain analysis during the steam oxidation for Zircaloy using hydrogen and oxygen sensors

    International Nuclear Information System (INIS)

    Fukumoto, Michihisa; Hara, Motoi; Kaneko, Hiroyuki; Sakuraba, Takuya

    2015-01-01

    The oxidation behavior of Zircaloy-4 at high temperatures in a flowing Ar-H_2O (saturated at 323 K) mixed gas was investigated using hydrogen and oxygen sensors installed at a gas outlet, and the utility of the gas sensing methods by using both sensors was examined. The generated amount of hydrogen was determined from the hydrogen partial pressure continuously measured by the hydrogen sensor, and the resultant calculated oxygen amount that reacted with the specimen was in close agreement with the mass gain gravimetrically measured after the experiment. This result demonstrated that the hydrogen partial pressure measurement using a hydrogen sensor is an effective method for examining the steam oxidation of this metal as well as monitoring the hydrogen evolution. The advantage of this method is that the oxidation rate of the metal at any time as a differential quantity is able to be obtained, compared to the oxygen amount gravimetrically measured as an integral quantity. When the temperature was periodically changed in the range of 1173 K to 1523 K, highly accurate measurements could be carried out using this gas monitoring method, although reasonable measurements were not gravimetrically performed due to the fluctuating thermo-buoyancy during the experiment. A change of the oxidation rate was clearly detected at a monoclinic tetragonal transition temperature of ZrO_2. From the calculation of the water vapor partial pressure during the thermal equilibrium condition using the hydrogen and oxygen partial pressures, it became clear that a thermal equilibrium state is maintained when the isothermal condition is maintained, but is not when the temperature increases or decreases with time. Based on these results, it was demonstrated that the gas monitoring system using hydrogen and oxygen sensors is very useful for investigating the oxidation process of the Zircaloy in steam. (author)

  17. Online Image-based Monitoring of Soft-tissue Displacements for Radiation Therapy of the Prostate

    International Nuclear Information System (INIS)

    Schlosser, Jeffrey; Salisbury, Kenneth; Hristov, Dimitre

    2012-01-01

    Purpose: Emerging prolonged, hypofractionated radiotherapy regimens rely on high-dose conformality to minimize toxicity and thus can benefit from image guidance systems that continuously monitor target position during beam delivery. To address this need we previously developed, as a potential add-on device for existing linear accelerators, a novel telerobotic ultrasound system capable of real-time, soft-tissue imaging. Expanding on this capability, the aim of this work was to develop and characterize an image-based technique for real-time detection of prostate displacements. Methods and Materials: Image processing techniques were implemented on spatially localized ultrasound images to generate two parameters representing prostate displacements in real time. In a phantom and five volunteers, soft-tissue targets were continuously imaged with a customized robotic manipulator while recording the two tissue displacement parameters (TDPs). Variations of the TDPs in the absence of tissue displacements were evaluated, as was the sensitivity of the TDPs to prostate translations and rotations. Robustness of the approach to probe force was also investigated. Results: With 95% confidence, the proposed method detected in vivo prostate displacements before they exceeded 2.3, 2.5, and 2.8 mm in anteroposterior, superoinferior, and mediolateral directions. Prostate pitch was detected before exceeding 4.7° at 95% confidence. Total system time lag averaged 173 ms, mostly limited by ultrasound acquisition rate. False positives (FPs) (FP) in the absence of displacements did not exceed 1.5 FP events per 10 min of continuous in vivo imaging time. Conclusions: The feasibility of using telerobotic ultrasound for real-time, soft-tissue–based monitoring of target displacements was confirmed in vivo. Such monitoring has the potential to detect small clinically relevant intrafractional variations of the prostate position during beam delivery.

  18. Acute exposure of mercury chloride stimulates the tissue regeneration program and reactive oxygen species production in the Drosophila midgut.

    Science.gov (United States)

    Chen, Zhi; Wu, Xiaochun; Luo, Hongjie; Zhao, Lingling; Ji, Xin; Qiao, Xianfeng; Jin, Yaping; Liu, Wei

    2016-01-01

    We used Drosophila as an animal model to study the digestive tract in response to the exposure of inorganic mercury (HgCl2). We found that after oral administration, mercury was mainly sequestered within the midgut. This resulted in increased cell death, which in turn stimulated the tissue regeneration program, including accelerated proliferation and differentiation of the intestinal stem cells (ISCs). We further demonstrated that these injuries correlate closely with the excessive production of the reactive oxygen species (ROS), as vitamin E, an antioxidant reagent, efficiently suppressed the HgCl2-induced phenotypes of midgut and improved the viability. We propose that the Drosophila midgut could serve as a suitable model to study the treatment of acute hydrargyrism on the digestive systems. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Real-time optical monitoring of permanent lesion progression in radiofrequency ablated cardiac tissue (Conference Presentation)

    Science.gov (United States)

    Singh-Moon, Rajinder P.; Hendon, Christine P.

    2016-02-01

    Despite considerable advances in guidance of radiofrequency ablation (RFA) therapies for atrial fibrillation, success rates have been hampered by an inability to intraoperatively characterize the extent of permanent injury. Insufficient lesions can elusively create transient conduction blockages that eventually reconduct. Prior studies suggest significantly greater met-myoglobin (Mmb) concentrations in the lesion core than those in the healthy myocardium and may serve as a marker for irreversible tissue damage. In this work, we present real-time monitoring of permanent injury through spectroscopic assessment of Mmb concentrations at the catheter tip. Atrial wedges (n=6) were excised from four fresh swine hearts and submerged under pulsatile flow of warm (37oC) phosphate buffered saline. A commercial RFA catheter inserted into a fiber optic sheath allowed for simultaneous measurement of tissue diffuse reflectance (DR) spectra (500-650nm) during application of RF energy. Optical measurements were continuously acquired before, during, and post-ablation, in addition to healthy neighboring tissue. Met-myoglobin, oxy-myoglobin, and deoxy-myoglobin concentrations were extracted from each spectrum using an inverse Monte Carlo method. Tissue injury was validated with Masson's trichrome and hematoxylin and eosin staining. Time courses revealed a rapid increase in tissue Mmb concentrations at the onset of RFA treatment and a gradual plateauing thereafter. Extracted Mmb concentrations were significantly greater post-ablation (p<0.0001) as compared to healthy tissue and correlated well with histological assessment of severe thermal tissue destruction. On going studies are aimed at integrating these findings with prior work on near infrared spectroscopic lesion depth assessment. These results support the use of spectroscopy-facilitated guidance of RFA therapies for real-time permanent injury estimation.

  20. Oxygen sensor nanoparticles for monitoring bacterial growth and characterization of dose–response functions in microfluidic screenings

    International Nuclear Information System (INIS)

    Cao, Jialan; Köhler, J. Michael; Nagl, Stefan; Kothe, Erika

    2015-01-01

    We are presenting a microfluidic droplet-based system for non-invasive, simultaneous optical monitoring of oxygen during bacterial cultivation in nL-sized droplets using ∼350 nm nanobeads made from polystyrene and doped with the NIR-emitting oxygen probe platinum (II) 5, 10, 15, 20-meso-tetraphenyltetrabenzoporphyrin (PtTPTBP). Data were readout by a two-channel micro flow-through fluorimeter and a two-channel micro flow-through photometer. The time-resolved miniaturized optical multi endpoint detection was applied to simultaneously sense dissolved oxygen, cellular autofluorescence, and cell density in nL-sized segments. Two bacterial strains were studied that are resistant to heavy metal ions, viz. Streptomyces acidiscabies E13 and Psychrobacillus psychrodurans UrPLO1. The study has two main features in that it demonstrates (a) the possibility to monitor the changes in oxygen partial pressure during metabolic activity of different bacterial cultures inside droplets, and (b) the efficiency of droplet-based microfluidic techniques along with multi-parameter optical sensing for highly resolved microtoxicological screenings in aquatic systems. (author)

  1. Muscle tissue oxygenation, pressure, electrical, and mechanical responses during dynamic and static voluntary contractions

    DEFF Research Database (Denmark)

    Vedsted, Pernille; Blangsted, Anne Katrine; Søgaard, Karen

    2006-01-01

    tension (rTO(2)) would be larger during dynamic (DYN) than intermittent static (IST) low force contractions; and that (2) oxygen tension would remain lower in the resting periods subsequent to DYN as compared to those following IST. Eight subjects performed elbow flexions with identical time......-tension products: (1) DYN as a 20 degrees elbow movement of 2 s concentric and 2 s eccentric followed by a 4 s rest; and (2) IST with a 4 s contraction followed by a 4 s rest. Each session was performed for 1 min at 10 and 20% of the maximal voluntary contraction (MVC). The force, bipolar surface EMG, MMG, IMP, rTO......, respectively), and a similar picture was seen for the eccentric phase. However, no differences were seen in rTO(2) in either the contraction or the rest periods. In a prolonged rest period (8 s) after the sessions, DYN but not IST showed rTO(2) above baseline level. In conclusion, rTO(2) in DYN and IST were...

  2. Hyperbaric oxygen therapy in the treatment of radio-induced lesions in normal tissues: a literature review

    International Nuclear Information System (INIS)

    Pasquier, David; Hoelscher, Tobias; Schmutz, Jorg; Dische, Stanley; Mathieu, Daniel; Baumann, Michael; Lartigau, Eric

    2004-01-01

    Late complications are one of the major factors limiting radiotherapy treatment, and their treatment is not codified. Hyperbaric oxygen (HBO) has been used in combination with radiotherapy for over half a century, either to maximise its effectiveness or in an attempt to treat late complications. In this latter case, retrospective trials and case reports are prevailing in literature. This prompted European Society for Therapeutic Radiotherapy and Oncology and European Committee for Hyperbaric Medicine to organise a consensus conference in October 2001, dealing with the HBO indications on radiotherapy for the treatment and prevention of late complications. This updated literature review is part of the documents the jury based its opinion on. A systematic search was done on literature from 1960 to 2004, by only taking into account the articles that appeared in peer review journals. Hyperbaric oxygen treatment involving complications to the head and neck, pelvis and nervous system, and the prevention of complications after surgery in irradiated tissues have been studied. Despite the small number of controlled trials, it may be indicated for the treatment of mandibular osteoradionecrosis in combination with surgery, haemorrhagic cystitis resistant to conventional treatments and the prevention of osteoradionecrosis after dental extraction, whose level of evidence seems to be the most significant though randomised trials are still necessary. The other treatment methods are also outlined for each location

  3. Discrepancies between measured changes of radiobiological hypoxic fraction and oxygen tension monitoring using two assay systems

    International Nuclear Information System (INIS)

    Sasai, K.; Brown, J.M.

    1994-01-01

    This study was conducted to assess the ability of computerized pO 2 histography to measure changes in tumor oxygenation produced by low oxygen breathing. Female syngeneic C3H/Km mice bearing SCC VII/St carcinomas were used in these experiments. Changes in tumor oxygenation produced by the mice breathing 10% oxygen were assessed with computerized pO2 histography, 3 H-misonidazole binding, and the paired survival curve assay of radiosensitivity. The hypoxic cell fraction of the tumors in mice breathing 10% oxygen was 3.1 times higher than that of tumors in mice breathing normal air determined by an in vivo-in vitro clonogenic assay. Binding of radiolabeled misonidazole to the tumors in mice breathing 10% oxygen was also significantly higher than that to tumors in mice breathing normal air (p 2 value for the tumor. The number of pO 2 readings lower than 5 mmHg in the tumor was not affected by the 10% oxygen breathing. These findings indicate that increases in radiobiological hypoxic fraction produced by lower blood oxygen levels may not correlate well with the results of polarographic measurements of tumor pO 2 levels. 29 refs., 4 figs., 1 tab

  4. Determination of Biochemical Oxygen Demand of Area Waters: A Bioassay Procedure for Environmental Monitoring

    Science.gov (United States)

    Riehl, Matthew

    2012-01-01

    A graphical method for determining the 5-day biochemical oxygen demand (BOD5) for a body of water is described. In this bioassay, students collect a sample of water from a designated site, transport it to the laboratory, and evaluate the amount of oxygen consumed by naturally occurring bacteria during a 5-day incubation period. An accuracy check,…

  5. The dynamics of dissolved oxygen concentration for water quality monitoring and assessment in polder ditches

    NARCIS (Netherlands)

    Veeningen, R.

    1983-01-01

    This study deals with the use of the dynamics of dissolved oxygen concentration for water quality assessment in polder ditches. The dynamics of the dissolved oxygen concentration, i.e. the temporal and spatial variations in a few polder ditches under a range of natural, pollution and management

  6. Methods of Monitoring Cell Fate and Tissue Growth in Three-Dimensional Scaffold-Based Strategies for In Vitro Tissue Engineering.

    Science.gov (United States)

    Leferink, Anne M; van Blitterswijk, Clemens A; Moroni, Lorenzo

    2016-08-01

    In the field of tissue engineering, there is a need for methods that allow assessing the performance of tissue-engineered constructs noninvasively in vitro and in vivo. To date, histological analysis is the golden standard to retrieve information on tissue growth, cellular distribution, and cell fate on tissue-engineered constructs after in vitro cell culture or on explanted specimens after in vivo applications. Yet, many advances have been made to optimize imaging techniques for monitoring tissue-engineered constructs with a sub-mm or μm resolution. Many imaging modalities have first been developed for clinical applications, in which a high penetration depth has been often more important than lateral resolution. In this study, we have reviewed the current state of the art in several imaging approaches that have shown to be promising in monitoring cell fate and tissue growth upon in vitro culture. Depending on the aimed tissue type and scaffold properties, some imaging methods are more applicable than others. Optical methods are mostly suited for transparent materials such as hydrogels, whereas magnetic resonance-based methods are mostly applied to obtain contrast between hard and soft tissues regardless of their transparency. Overall, this review shows that the field of imaging in scaffold-based tissue engineering is developing at a fast pace and has the potential to overcome the limitations of destructive endpoint analysis.

  7. Development of luminescent pH sensor films for monitoring bacterial growth through tissue.

    Science.gov (United States)

    Wang, Fenglin; Raval, Yash; Chen, Hongyu; Tzeng, Tzuen-Rong J; DesJardins, John D; Anker, Jeffrey N

    2014-02-01

    Although implanted medical devices (IMDs) offer many benefits, they are susceptible to bacterial colonization and infections. Such infections are difficult to treat because bacteria could form biofilms on the implant surface, which reduce antibiotics penetration and generate local dormant regions with low pH and low oxygen. In addition, these infections are hard to detect early because biofilms are often localized on the surface. Herein, an optical sensor film is developed to detect local acidosis on an implanted surface. The film contains both upconverting particles (UCPs) that serve as a light source and a pH indicator that alters the luminescence spectrum. When irradiated with 980 nm light, the UCPs produce deeply penetrating red light emission, while generating negligible autofluorescence in the tissue. The basic form of the pH indicator absorbs more of upconversion luminescence at 661 nm than at 671 nm and consequently the spectral ratio indicates pH. Implanting this pH sensor film beneath 6-7 mm of porcine tissue does not substantially affect the calibration curve because the peaks are closely spaced. Furthermore, growth of Staphylococcus epidermidis on the sensor surface causes a local pH decrease that can be detected non-invasively through the tissue. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Hemodynamic and tissue oxygenation responses to exercise and beta-adrenergic blockade in patients with hyperthyroidism.

    Science.gov (United States)

    Monachini, Maristela C; Lage, Silvia G; Ran, Miguel A N; Cardoso, Rita H A; Medeiros, Caio; Caramelli, Bruno; Sposito, Andrei C; Ramires, José A F

    2004-07-01

    Exercise-induced dyspnea is a frequent feature in patients with hyperthyroidism. Data from clinical studies to elucidate the origin of this symptom are lacking. In the current study, we examined the hemodynamic and oxygenation responses to exercise and beta-adrenergic blockade in patients with hyperthyroidism and their relationship with dyspnea. Hemodynamic studies were performed under resting conditions and after isotonic exercise in 15 patients with hyperthyroidism and 11 control subjects. Exercise was applied using a bicycle ergometer, with progressive loads. In the hyperthyroid group, measurements were repeated at rest and during supine exercise after administering 15 mg of intravenous metoprolol. End-diastolic pulmonary artery pressure and cardiac index were higher in the hyperthyroid group than in controls (18.6 +/- 5.3 vs. 11.2 +/- 4.9 mmHg; p = 0.02, and 6.0 +/- 1.7 vs. 2.8 +/- 0.5 l/min/m2; p = 0.0001, respectively). After exercise, there was an increase in end-diastolic pulmonary artery pressure in the hyperthyroid group (18.6 +/- 5.3 to 25.5 +/- 9.9 mmHg; p = 0.02), revealing impaired cardiocirculatory reserve. Pulmonary arteriolar resistance increased significantly in parallel with end-diastolic pulmonary artery pressure after drug administration, suggesting an inadequate cardiovascular response after beta blockade in patients with hyperthyroidism. We observed that functional left ventricular reserve is impaired in patients with hyperthyroidism, suggesting an explanation for the frequent symptom of dyspnea and impaired exercise tolerance. Moreover, we also suggest that beta-adrenergic blockade may adversely affect cardiovascular function in patients with hyperthyroidism.

  9. In-situ photopolymerization and monitoring device for controlled shaping of tissue fillers, replacements, or implants

    Science.gov (United States)

    Schmocker, Andreas M.; Khoushabi, Azadeh; Bourban, Pierre-Etienne; Schizas, Constantin; Pioletti, Dominique; Moser, Christophe

    2015-03-01

    Photopolymerization is a common tool to harden materials initially in a liquid state. A surgeon can directly trigger the solidification of a dental implant or a bone or tissue filler simply by illumination. Traditionally, photopolymerization has been used mainly in dentistry. Over the last decade advances in material development including a wide range of biocompatible gel- and cement-systems open up a new avenue for in-situ photopolymerization. However, at the device level, surgical endoscopic probes are required. We present a miniaturized light probe where a photoactive material can be 1) mixed, pressurized and injected 2) photopolymerized or photoactivated and 3) monitored during the chemical reaction. The device enables surgeries to be conducted through a hole smaller than 1 mm in diameter. Beside basic injection mechanics, the tool consists of an optical fiber guiding the light required for photopolymerization and for chemical analysis. Combining photorheology and fluorescence spectroscopy, the current state of the photopolymerization is inferred and monitored in real time. Biocompatible and highly tuneable Poly-Ethylene-Glycol (PEG) hydrogels were used as the injection material. The device was tested on a model for intervertebral disc replacement. Gels were successfully implanted into a bovine caudal model and mechanically tested in-vitro during two weeks. The photopolymerized gel was evaluated at the tissue level (adherence and mechanical properties of the implant), at the cellular level (biocompatibility and cytotoxicity) and ergonomic level (sterilization procedure and feasibility study). This paper covers the monitoring aspect of the device.

  10. Comparison of local adipose tissue content and SRS-derived NIRS muscle oxygenation measurements in 90 individuals.

    Science.gov (United States)

    Cooper, Chris E; Penfold, Stacey-Marie; Elwell, Clare E; Angus, Caroline

    2010-01-01

    Adipose content in the region over the vastus lateralis muscle was measured in a young (21.1 +/- 3.1 years old, mean +/- SD) population of males (n = 62) and females (n = 28). Three techniques were used: skinfold thickness, ultrasound and near infrared spectroscopy. All techniques closely correlated with each other and all showed a significantly larger adipose content in females and a limited overlap with the range of values in males. Spatially resolved near infrared spectroscopy (SRS-NIRS) was then used to measure the tissue oxygenation index (TOI) at the same site. A source-detector separation of 4 cm was used to allow for significant light penetration into muscle tissue. TOI at rest was significantly higher in the female (65.3 +/- 7.0, mean +/- SD) than the male (61.9 +/- 5.1, mean +/- SD) group. There was a strong positive correlation between adipose content and TOI in male subjects. However, no correlation was seen in the female group. The possible optical and physiological explanations for these results are discussed.

  11. SU-E-J-197: A Novel Optical Interstitial Fiber Spectroscopic System for Real-Time Tissue Micro-Vascular Hemodynamics Monitoring.

    Science.gov (United States)

    Zhao, D; Campos, D; Yan, Y; Kimple, R; Jacques, S; van der Kogel, A; Kissick, M

    2012-06-01

    To demonstrate a novel interstitial optical fiber spectroscopic system, based on diffuse optical spectroscopies with spectral fitting, for the simultaneous monitoring of tumor blood volume and oxygen tension. The technique provides real-time, minimally-invasive and quantification of tissue micro-vascular hemodynamics. An optical fiber prototype probe characterizesthe optical transport in tissue between two large Numerical Aperture (NA) fibers of 200μm core diameter (BFH37-200, ThorLabs) spaced 3-mm apart. Two 21-Ga medical needles are used to protect fiber ends and to facilitate tissue penetration with minimum local blunt trauma in nude mice with xenografts. A 20W white light source (HL-2000-HP, Ocean Optics) is coupled to one fiber with SMA adapter. The other fiber is used to collect light, which is coupled into the spectrometer (QE65000 with Spectrasuite Operating software and OmniDriver, Ocean Optics). The wavelength response of the probe depends on the wavelength dependence of the light source, and of the light signal collection that includes considerable scatter, modeled with Monte-Carlo techniques (S. Jacques 2010 J. of Innov. Opt. Health Sci. 2 123-9). Measured spectra of tissue are normalized by a measured spectrum of a white standard, yielding the transmission spectrum. A head-and-neck xenograft on the flank of a live mouse is used for development. The optical fiber probe delivers and collects light at an arbitrary depth in the tumor. By spectral fitting of the measured transmission spectrum, an analysis of blood volume and oxygen tension is obtained from the fitting parameters in real time. A newly developed optical fiber spectroscopic system with an optical fiber probe takes spectroscopic techniques to a much deeper level in a tumor, which has potential applications for real-time monitoring hypoxic cell population dynamics for an eventual adaptive therapy metric of particular use in hypofractionated radiotherapy. © 2012 American Association of

  12. Imaging monitored loosening of dense fibrous tissues using high-intensity pulsed ultrasound

    International Nuclear Information System (INIS)

    Yeh, Chia-Lun; Li, Pai-Chi; Kuo, Po-Ling; Shih, Wen-Pin; Huang, Pei-Shin

    2013-01-01

    Pulsed high-intensity focused ultrasound (HIFU) is proposed as a new alternative treatment for contracture of dense fibrous tissue. It is hypothesized that the pulsed-HIFU can release the contracted tissues by attenuating tensile stiffness along the fiber axis, and that the stiffness reduction can be quantitatively monitored by change of B-mode images. Fresh porcine tendons and ligaments were adapted to an ex vivo model and insonated with pulsed-HIFU for durations ranging from 5 to 30 min. The pulse length was 91 µs with a repetition frequency of 500 Hz, and the peak rarefactional pressure was 6.36 MPa. The corresponding average intensities were kept around 1606 W cm −2 for I SPPA and 72.3 W cm −2 for I SPTA . B-mode images of the tissues were acquired before and after pulsed-HIFU exposure, and the changes in speckle intensity and organization were analyzed. The tensile stiffness of the HIFU-exposed tissues along the longitudinal axis was examined using a stretching machine. Histology examinations were performed by optical and transmission electron microscopy. Pulsed-HIFU exposure significantly decreased the tensile stiffness of the ligaments and tendons. The intensity and organization of tissue speckles in the exposed region were also decreased. The speckle changes correlated well with the degree of stiffness alteration. Histology examinations revealed that pulsed-HIFU exposure probably damages tissues via a cavitation-mediated mechanism. Our results suggest that pulsed-HIFU with a low duty factor is a promising tool for developing new treatment strategies for orthopedic disorders. (paper)

  13. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    Science.gov (United States)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

  14. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function

    Science.gov (United States)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-01-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, free-standing electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on-demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function. PMID:26974408

  15. In vivo EPR oximetry using an isotopically-substituted nitroxide: Potential for quantitative measurement of tissue oxygen

    Science.gov (United States)

    Weaver, John; Burks, Scott R.; Liu, Ke Jian; Kao, Joseph P.Y.; Rosen, Gerald M.

    2017-01-01

    Variations in brain oxygen (O2) concentration can have profound effects on brain physiology. Thus, the ability to quantitate local O2 concentrations noninvasively in vivo could significantly enhance understanding of several brain pathologies. However, quantitative O2 mapping in the brain has proven difficult. The electron paramagnetic resonance (EPR) spectra of nitroxides are sensitive to molecular O2 and can be used to estimate O2 concentrations in aqueous media. We recently synthesized labile-ester-containing nitroxides, such as 3-acetoxymethoxycarbonyl-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl (nitroxide 4), which accumulate in cerebral tissue after in situ hydrolysis, and thus enable spatial mapping of O2 concentrations in the mouse brain by EPR imaging. In an effort to improve O2 quantitation, we prepared 3-acetoxymethox ycarbonyl-2,2,5,5-tetra(2H3)methyl-1-(3,4,4-2H3,1-15N)pyrrolidinyloxyl (nitroxide 2), which proved to be a more sensitive probe than its normo-isotopic version for quantifying O2 in aqueous solutions of various O2 concentrations. We now demonstrate that this isotopically substituted nitroxide is ~2-fold more sensitive in vivo than the normo-isotopic nitroxide 4. Moreover, in vitro and in vivo EPR spectral-spatial imaging results with nitroxide 2 demonstrate significant improvement in resolution, reconstruction and spectral response to local O2 concentrations in cerebral tissue. Thus, isotopic-substituted nitroxides, such as 2, are excellent sensors for in vivo O2 quantitation in tissues, such as the brain. PMID:27567323

  16. Tissue-specific methylation of human insulin gene and PCR assay for monitoring beta cell death.

    Directory of Open Access Journals (Sweden)

    Mohamed I Husseiny

    Full Text Available The onset of metabolic dysregulation in type 1 diabetes (T1D occurs after autoimmune destruction of the majority of pancreatic insulin-producing beta cells. We previously demonstrated that the DNA encoding the insulin gene is uniquely unmethylated in these cells and then developed a methylation-specific PCR (MSP assay to identify circulating beta cell DNA in streptozotocin-treated mice prior to the rise in blood glucose. The current study extends to autoimmune non-obese diabetic (NOD mice and humans, showing in NOD mice that beta cell death occurs six weeks before the rise in blood sugar and coincides with the onset of islet infiltration by immune cells, demonstrating the utility of MSP for monitoring T1D. We previously reported unique patterns of methylation of the human insulin gene, and now extend this to other human tissues. The methylation patterns of the human insulin promoter, intron 1, exon 2, and intron 2 were determined in several normal human tissues. Similar to our previous report, the human insulin promoter was unmethylated in beta cells, but methylated in all other tissues tested. In contrast, intron 1, exon 2 and intron 2 did not exhibit any tissue-specific DNA methylation pattern. Subsequently, a human MSP assay was developed based on the methylation pattern of the insulin promoter and human islet DNA was successfully detected in circulation of T1D patients after islet transplantation therapy. Signal levels of normal controls and pre-transplant samples were shown to be similar, but increased dramatically after islet transplantation. In plasma the signal declines with time but in whole blood remains elevated for at least two weeks, indicating that association of beta cell DNA with blood cells prolongs the signal. This assay provides an effective method to monitor beta cell destruction in early T1D and in islet transplantation therapy.

  17. A method for measuring brain partial pressure of oxygen in unanesthetized unrestrained subjects: the effect of acute and chronic hypoxia on brain tissue PO(2).

    Science.gov (United States)

    Ortiz-Prado, E; Natah, Siraj; Srinivasan, Sathyanarayanan; Dunn, Jeff F

    2010-11-30

    The level of tissue oxygenation provides information related to the balance between oxygen delivery, oxygen utilization, tissue reactivity and morphology during physiological conditions. Tissue partial pressure of oxygen (PtO(2)) is influenced by the use of anesthesia or restraint. These factors may impact the absolute level of PtO(2). In this study we present a novel fiber optic method to measure brain PtO(2). This method can be used in unanesthetized, unrestrained animals, provides absolute values for PO(2), has a stable calibration, does not consume oxygen and is MRI compatible. Brain PtO(2) was studied during acute hypoxia, as well as before and after 28 days of high altitude acclimatization. A sensor was chronically implanted in the frontal cortex of eight Wistar rats. It is comprised of a fiber optic probe with a tip containing material that fluoresces with an oxygen dependent lifetime. Brain PtO(2) declines by 80% and 76% pre- and post-acclimatization, respectively, when the fraction of inspired oxygen declines from 0.21 to 0.08. In addition, a linear relationship between brain PtO(2) and inspired O(2) levels was demonstrated r(2)=0.98 and r(2)=0.99 (pre- and post-acclimatization). Hypoxia acclimatization resulted in an increase in the overall brain PtO(2) by approximately 35%. This paper demonstrates the use of a novel chronically implanted fiber optic based sensor for measuring absolute PtO(2). It shows a very strong linear relationship in awake animals between inspired O(2) and tissue O(2), and shows that there is a proportional increase in PtO(2) over a range of inspired values after exposure to chronic hypoxia. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Seabird tissue archival and monitoring project: Egg collections and analytical results 1999-2002

    Science.gov (United States)

    Vander Pol, Stacy S.; Christopher, Steven J.; Roseneau, David G.; Becker, Paul R.; Day, Russel D.; Kucklick, John R.; Pugh, Rebecca S.; Simac, Kristin S.; Weston-York, Geoff

    2003-01-01

    In 1998, the U.S. Geological Survey Biological Resources Division (USGS-BRD), the U.S. Fish and Wildlife Service (USFWS) Alaska Maritime National Wildlife Refuge (AMNWR), and the National Institute of Standards and Technology (NIST) began the Seabird Tissue Archival and Monitoring Project (STAMP) to collect and cryogenically bank tissues from seabirds in Alaska for future retrospective analysis of anthropogenic contaminants. The approach of STAMP was similar to that of the Alaska Marine Mammal Tissue Archival Project (AMMTAP). AMMTAP was started in 1987 by NIST and the National Oceanic and Atmospheric Administration (NOAA) as part of the Outer Continental Shelf Environmental Assessment Program sponsored by the Minerals Management Service. Presently sponsored by the USGS-BRD, AMMTAP continues its work as part of a larger national program, the Marine Mammal Health and Stranding Response Program. AMMTAP developed carefully designed sampling and specimen banking protocols. Since 1987, AMMTAP has collected tissues from marine mammals taken in Alaska Native subsistence hunts and has cryogenically banked these tissues at the NIST National Biomonitoring Specimen Bank (NBSB). Through its own analytical work and working in partnership with other researchers both within and outside Alaska, AMMTAP has helped to develop a substantial database on contaminants in Alaska marine mammals. In contrast, data and information is limited on contaminants in Alaska seabirds, which are similar to marine mammals in that they feed near the top of the food chain and have the potential for accumulating anthropogenic contaminants. During its early planning stages, STAMP managers identified the seabird egg as the first tissue of choice for study by the project. There is a relatively long history of using bird eggs for environmental monitoring and for investigating the health status of bird populations. Since 1998, protocols for collecting and processing eggs, and cryogenically banking egg samples

  19. Cutaneous Mitochondrial PO2, but Not Tissue Oxygen Saturation, Is an Early Indicator of the Physiologic Limit of Hemodilution in the Pig.

    Science.gov (United States)

    Römers, Luuk H L; Bakker, Charlotte; Dollée, Nathalie; Hoeks, Sanne E; Lima, Alexandre; Raat, Nicolaas J H; Johannes, Tanja; Stolker, Robert J; Mik, Egbert G

    2016-07-01

    Hemodilution is a consequence of fluid replacement during blood loss and is limited by the individual ability to compensate for decreasing hemoglobin level. We tested the ability of a novel noninvasive method for measuring cutaneous mitochondrial PO2 (mitoPO2) to detect this threshold early. Anesthetized and ventilated pigs were hemodynamically monitored and randomized into a hemodilution (n = 12) or a time control (TC) group (n = 14). MitoPO2 measurements were done by oxygen-dependent delayed fluorescence of protoporphyrin IX after preparation of the skin with 20% 5-aminolevulinic acid cream. Tissue oxygen saturation (StO2) was measured with near infrared spectroscopy on the thoracic wall. After baseline measurements, progressive normovolemic hemodilution was performed in the hemodilution group in equal steps (500 ml blood replaced by 500 ml Voluven; Fresenius Kabi AG, Germany). Consecutive measurements were performed after 20-min stabilization periods and repeated 8 times or until the animal died. The TC animals remained stable with regard to hemodynamics and mitoPO2. In the hemodilution group, mitoPO2 became hemoglobin-dependent after reaching a threshold of 2.6 ± 0.2 g/dl. During hemodilution, hemoglobin and mitoPO2 decreased (7.9 ± 0.2 to 2.1 ± 0.2 g/dl; 23.6 ± 2 to 9.9 ± 0.8 mmHg), but StO2 did not. Notably, mitoPO2 dropped quite abruptly (about 39%) at the individual threshold. We observed that this decrease in mitoPO2 occurred at least one hemodilution step before changes in other conventional parameters. Cutaneous mitoPO2 decreased typically one hemodilution step before occurrence of significant alterations in systemic oxygen consumption and lactate levels. This makes mitoPO2 a potential early indicator of the physiologic limit of hemodilution and possibly a physiologic trigger for blood transfusion.

  20. Deconstructing autofluorescence: non-invasive detection and monitoring of biochemistry in cells and tissues (Conference Presentation)

    Science.gov (United States)

    Goldys, Ewa M.; Gosnell, Martin E.; Anwer, Ayad G.; Cassano, Juan C.; Sue, Carolyn M.; Mahbub, Saabah B.; Pernichery, Sandeep M.; Inglis, David W.; Adhikary, Partho P.; Jazayeri, Jalal A.; Cahill, Michael A.; Saad, Sonia; Pollock, Carol; Sutton-Mcdowall, Melanie L.; Thompson, Jeremy G.

    2016-03-01

    Automated and unbiased methods of non-invasive cell monitoring able to deal with complex biological heterogeneity are fundamentally important for biology and medicine. Label-free cell imaging provides information about endogenous fluorescent metabolites, enzymes and cofactors in cells. However extracting high content information from imaging of native fluorescence has been hitherto impossible. Here, we quantitatively characterise cell populations in different tissue types, live or fixed, by using novel image processing and a simple multispectral upgrade of a wide-field fluorescence microscope. Multispectral intrinsic fluorescence imaging was applied to patient olfactory neurosphere-derived cells, cell model of a human metabolic disease MELAS (mitochondrial myopathy, encephalomyopathy, lactic acidosis, stroke-like syndrome). By using an endogenous source of contrast, subtle metabolic variations have been detected between living cells in their full morphological context which made it possible to distinguish healthy from diseased cells before and after therapy. Cellular maps of native fluorophores, flavins, bound and free NADH and retinoids unveiled subtle metabolic signatures and helped uncover significant cell subpopulations, in particular a subpopulation with compromised mitochondrial function. The versatility of our method is further illustrated by detecting genetic mutations in cancer, non-invasive monitoring of CD90 expression, label-free tracking of stem cell differentiation, identifying stem cell subpopulations with varying functional characteristics, tissue diagnostics in diabetes, and assessing the condition of preimplantation embryos. Our optimal discrimination approach enables statistical hypothesis testing and intuitive visualisations where previously undetectable differences become clearly apparent.

  1. An electrochemical approach to monitor pH change in agar media during plant tissue culture.

    Science.gov (United States)

    Wang, Min; Ha, Yang

    2007-05-15

    In this work, metal oxide microelectrodes were developed to monitor pH change in agar media during plant tissue culture. An antimony wire was produced by a new approach "capillary melt method". The surface of the obtained antimony wire was oxidized in a potassium nitrate melt to fabricate an antimony oxide film for pH sensing. Characterization results show that the oxide layer grown on the wire surface consists of Sb(2)O(3) crystal phase. The sensing response, open-circuit potential, of the electrode has a good linear relationship (R(2)=1.00) with pH value of the test solution. Adding organic compounds into the test media would not affect the linear relationship, although the slope of the lines varied with different ingredients added. The antimony oxide electrodes were employed to continuously monitor pH change of agar culture media during a 2-week plant tissue culture of Dendrobium candidum. The antimony oxide electrode fabricated this way has the advantages of low cost, easy fabrication, fast response, and almost no contamination introduced into the system. It would be suitable for in situ and continuous pH measurement in many bio applications.

  2. Ultrasound and photoacoustic imaging to monitor ocular stem cell delivery and tissue regeneration (Conference Presentation)

    Science.gov (United States)

    Kubelick, Kelsey; Snider, Eric; Yoon, Heechul; Ethier, C. Ross; Emelianov, Stanislav Y.

    2017-03-01

    Glaucoma is associated with dysfunction of the trabecular meshwork (TM), a fluid drainage tissue in the anterior eye. A promising treatment involves delivery of stem cells to the TM to restore tissue function. Currently histology is the gold standard for tracking stem cell delivery and differentiation. To expedite clinical translation, non-invasive longitudinal monitoring in vivo is desired. Our current research explores a technique combining ultrasound (US) and photoacoustic (PA) imaging to track mesenchymal stem cells (MSCs) after intraocular injection. Adipose-derived MSCs were incubated with gold nanospheres to label cells (AuNS-MSCs) for PA imaging. Successful labeling was first verified with in vitro phantom studies. Next, MSC delivery was imaged ex vivo in porcine eyes, while intraocular pressure was hydrostatically clamped to maintain a physiological flow rate through the TM. US/PA imaging was performed before, during, and after AuNS-MSC delivery. Additionally, spectroscopic PA imaging was implemented to isolate PA signals from AuNS-MSCs. In vitro cell imaging showed AuNS-MSCs produce strong PA signals, suggesting that MSCs can be tracked using PA imaging. While the cornea, sclera, iris, and TM region can be visualized with US imaging, pigmented tissues also produce PA signals. Both modalities provide valuable anatomical landmarks for MSC localization. During delivery, PA imaging can visualize AuNS-MSC motion and location, creating a unique opportunity to guide ocular cell delivery. Lastly, distinct spectral signatures of AuNS-MSCs allow unmixing, with potential for quantitative PA imaging. In conclusion, results show proof-of-concept for monitoring MSC ocular delivery, raising opportunities for in vivo image-guided cell delivery.

  3. Micro-Raman spectroscopy of tissue samples for oral pathology follow-up monitoring

    Science.gov (United States)

    Delfino, I.; Camerlingo, C.; Zenone, F.; Perna, G.; Capozzi, V.; Cirillo, N.; Gaeta, G. M.; Lepore, M.

    2010-04-01

    An "in vitro" study of Raman spectra from oral human tissues is reported in order to the develop a diagnostic method suitable for "in vivo" oral pathology follow-up. The investigated pathology is Pemphigus Vulgaris (PV) for which new techniques for guiding and monitoring therapy would be particularly useful. Raman spectra were obtained in the wavenumber regions from 1000 to 1800 cm-1 and 2700 to 3200 cm-1 from tissues from patients at different stages of pathology (active PV, under therapy and in PV remission stage) as confirmed by histopathological and immunofluorescence analysis. Differences in the spectra depending on tissue illness stage arise in 1150-1250 cm-1 (amide III) and 1420-1450 cm-1 (CH3 deformation) regions and around 1650 cm-1 (amide I) and 2930 cm-1 (CH3 symmetric stretch). A wavelet deconvolution procedure was applied to the spectra for better discriminating among the three different stages of illness and a linear regression analysis was used to fully exploit the content of information of Raman spectra.

  4. Update on the use of dissolved oxygen addition to monitor the effectiveness of noble metal applications in external manifolds

    International Nuclear Information System (INIS)

    Varela, J.A.; Huie, H.H.; Seeman, R.A.; Bourne, C.M.; Odell, A.D.

    2014-01-01

    Electrochemical corrosion potential (ECP) measurements in a Mitigation Monitoring System (MMS) ECP manifold have historically been a primary indicator of the effectiveness of an On-Line NobleChem™ (OLNC) application, with the MMS ECP intended to measure the catalytic effect of noble metal deposited on the ECP manifold surface. In some plants ECP measurements made on untreated surfaces prior to an OLNC application were significantly lower than what would be expected for stainless steel under reactor bulk chemistry conditions. This is due to the consumption and depletion of bulk liquid dissolved oxygen (DO) in the lines supplying reactor water to these external ECP measurement locations. This phenomenon degrades the ability to use these external manifolds to confirm noble metal deposition. Previous papers have described how the injection of an oxygen-rich stream to the MMS supply stream (DO Addition) can be used to re-establish the capability of external ECP measurements to monitor the catalytic behavior of platinum deposited during an OLNC injection. This paper will provide an update of how this method is being successfully used in operating BWRs to monitor OLNC injections. The paper will outline the overall approach used to characterize the catalytic behavior of external ECP manifolds before and after the noble metal application and present plant data collected during DO Additions performed under various conditions. (author)

  5. Seabird tissue archival and monitoring project: Protocol for collecting and banking seabird eggs

    Science.gov (United States)

    Weston-York, Geoff; Porter, Barbara J.; Pugh, Rebecca S.; Roseneau, David G.; Simac, Kristin S.; Becker, Paul R.; Thorsteinson, Lyman K.; Wise, Stephen A.

    2001-01-01

    Archiving biological and environmental samples for retrospective analysis is a major component of systematic environmental monitoring. The long-term storage of carefully selected, representative samples in an environmental specimen bank is an important complement to the real-time monitoring of the environment. These archived samples permit:The use of subsequently developed innovative analytical technology that was not available at the time the samples were archived, for clear state-of-art identification an~ quantification of analytes of interest,The identification and quantification of analytes that are of subsequent interest but that were not of interest at the time the samples were archived, andThe comparison of present and past analytical techniques and values, providing continued credibility of past analytical values, and allowing flexibility in environmental monitoring programs.Seabirds, including albatrosses, pelicans, cormorants, terns, kittiwakes, murres, guillemots, and puffins spend most of their lives at sea and have special adaptations for feeding in the marine environment, including the ability to excrete the excess salt obtained from ingesting seawater. Many species nest in dense groups (colonies) on steep, precipitous sea-cliffs and headlands.Seabirds are long-lived and slow to mature. They occupy high positions in the marine food web and are considered sensitive indicators for the marine environment (prey includes krill, small fish, and squid). Breeding success, timing of nesting, diets, and survival rates may provide early indications of changing environmental conditions (e.g., see Hatch et aI., 1993). Chemical analysis of seabird tissues, including egg contents, can be particularly useful in determining whether contaminants (and potential biological effects) associated with human industrial activities, such as offshore petroleum and mineral exploration and development, are accumulating in marine environments. The collection and archival of seabird

  6. Multi-channel electrical impedance tomography for regional tissue hydration monitoring.

    Science.gov (United States)

    Chen, Xiaohui; Kao, Tzu-Jen; Ashe, Jeffrey M; Boverman, Gregory; Sabatini, James E; Davenport, David M

    2014-06-01

    Poor assessment of hydration status during hemodialysis can lead to under- or over-hydration in patients with consequences of increased morbidity and mortality. In current practice, fluid management is largely based on clinical assessments to estimate dry weight (normal hydration body weight). However, hemodialysis patients usually have co-morbidities that can make the signs of fluid status ambiguous. Therefore, achieving normal hydration status remains a major challenge for hemodialysis therapy. Electrical impedance technology has emerged as a promising method for hydration monitoring due to its non-invasive nature, low cost and ease-of-use. Conventional electrical impedance-based hydration monitoring systems employ single-channel current excitation (either 2-electrode or 4-electrode methods) to perturb and extract averaged impedance from bulk tissue and use generalized models from large populations to derive hydration estimates. In the present study, a prototype, single-frequency electrical impedance tomography (EIT) system with simultaneous multi-channel current excitation was used to enable regional hydration change detection. We demonstrated the capability to detect a difference in daily impedance change between left leg and right leg in healthy human subjects, who wore a compression sock only on one leg to reduce daily gravitational fluid accumulation. The impedance difference corresponded well with the difference of lower leg volume change between left leg and right leg measured by volumetry, which on average is ~35 ml, accounting for 0.7% of the lower leg volume. We have demonstrated the feasibility of using multi-channel EIT to extract hydration information in different tissue layers with minimal skin interference. Our simultaneous, multi-channel current excitation approach provides an effective method to separate electrode contact impedance and skin condition artifacts from hydration signals. The prototype system has the potential to be used in clinical

  7. Electrocatalytic oxygen reduction and hydrogen evolution reactions on phthalocyanine modified electrodes: Electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Koca, Atif, E-mail: akoca@eng.marmara.edu.tr [Department of Chemical Engineering, Faculty of Engineering, Marmara University, Goeztepe, 34722 Istanbul (Turkey); Kalkan, Ayfer; Bayir, Zehra Altuntas [Department of Chemistry, Technical University of Istanbul, Maslak, 34469 Istanbul (Turkey)

    2011-06-30

    Highlights: > Electrochemical and in situ spectroelectrochemical characterizations of the metallophthalocyanines were performed. > The presence of O{sub 2} influences both oxygen reduction reaction and the electrochemical behaviors of the complexes. > Homogeneous catalytic ORR process occurs via an 'inner sphere' chemical catalysis process. > CoPc and CuPc coated on a glassy carbon electrode decrease the overpotential of the working electrode for H{sup +} reduction. - Abstract: This study describes electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring of the electrocatalytic reduction of molecular oxygen and hydronium ion on the phthalocyanine-modified electrodes. For this purpose, electrochemical and in situ spectroelectrochemical characterizations of the metallophthalocyanines (MPc) bearing tetrakis-[4-((4'-trifluoromethyl)phenoxy)phenoxy] groups were performed. While CoPc gives both metal-based and ring-based redox processes, H{sub 2}Pc, ZnPc and CuPc show only ring-based electron transfer processes. In situ electrocolorimetric method was applied to investigate the color of the electrogenerated anionic and cationic forms of the complexes. The presence of O{sub 2} in the electrolyte system influences both oxygen reduction reaction and the electrochemical and spectral behaviors of the complexes, which indicate electrocatalytic activity of the complexes for the oxygen reduction reaction. Perchloric acid titrations monitored by voltammetry represent possible electrocatalytic activities of the complexes for hydrogen evolution reaction. CoPc and CuPc coated on a glassy carbon electrode decrease the overpotential of the working electrode for H{sup +} reduction. The nature of the metal center changes the electrocatalytic activities for hydrogen evolution reaction in aqueous solution. Although CuPc has an inactive metal center, its electrocatalytic activity is recorded more than CoPc for H{sup +} reduction in aqueous

  8. Radiation-induced DNA damage in tumors and normal tissues. II. Influence of dose, residual DNA damage and physiological factors in oxygenated cells

    International Nuclear Information System (INIS)

    Zhang, H.; Wheeler, K.T.

    1994-01-01

    Detection and quantification of hypoxic cells in solid tumors is important for many experimental and clinical situations. Several laboratories, including ours, have suggested that assays which measure radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) might be used to detect or quantify hypoxic cells in tumors and normal tissues. Recently, we demonstrated the feasibility of using an alkaline elution assay that measures strand breaks and DPCs to detect and/or quantify hypoxic cells in tissues. For this approach to be valid, DPCs must not be formed to any great extent in irradiated oxygenated cells, and the formation and repair of strand breaks and DPCs in oxygenated cells must not be modified appreciably by physiological factors (e.g., temperature, pH and nutrient depletion) that are often found in solid tumors. To address these issues, two sets of experiments were performed. In one set of experiments, oxygenated 9L cells in tissue culture, subcutaneous 9L tumors and rat cerebella were irradiated with doses of 15 or 50 Gy and allowed to repair until the residual strand break damage was low enough to detect DPCs. In another set of experiments, oxygenated exponentially growing or plateau-phase 9L cells in tissue culture were irradiated with a dose of 15 Gy at 37 or 20 degrees C, while the cells were maintained at a pH of either 6.6 or 7.3. DNA-protein crosslinks were formed in oxygenated cells about 100 times less efficiently than in hypoxic cells. In addition, temperature, pH, nutrient depletion and growth phase did not appreciably alter the formation and repair of strand breaks or the formation of DPCs in oxygenated 9L cells. These results support the use of this DNA damage assay for the detection and quantification of hypoxic cells in solid tumors. 27 refs., 5 tabs

  9. 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.

  10. Clinical indicators to monitor patients with risk for ineffective cerebral tissue perfusion

    Directory of Open Access Journals (Sweden)

    Miriam de Abreu Almeida

    2015-04-01

    Full Text Available Objective. Select and validate the clinical indicators to monitor patients on risk for ineffective cerebral tissue perfusion, according to the Nursing Outcomes Classification (NOC. Methodology. Validation study carried out between November 2012 and August 2013, in a Brazilian hospital. Seventeen judges nurses evaluated the clinical indicators of Nursing Outcomes, according to NOC for patients on risk for ineffective cerebral tissue perfusion. In the first stage, were selected the nursing results for the assessment of the studied diagnosis and, in the second nurses assessment the importance of the indicators of the validated results in the previous step through a five points Likert scale (1 = not important to 5 = extremely important. Were used the content validity index (CVI that corresponds to the calculation of weighted averages of them marks awarded for each indicator, as it considered the following weights: 1=0.00, 2=0.25, 3=0.50; 4=0.75; 5=1.00. For categorization, the CVI considered as critical = ≥0.80; supplementary =≥0.50 to 0.79 and were disposed results <0.50. Results. Of the 9 nursing results, only the cerebral tissue perfusion obtained a 100% consensus. The CVI of the 18 indicators of this result showed that five were validated as critical (impaired neurological reflexes, systolic blood pressure, diastolic blood pressure, reduced level of consciousness and mean arterial pressure, 12 were validated as supplementary (Agitation, Impaired cognition, Intracranial pressure, Syncope, Vomiting, Findings of cerebral angiography, Headache, Restlessness, Fever, Unexplained anxiety, listlessness and Hiccughs and one was disposed (carotid bruit. Conclusions. The validation of information about the conditions of risk may allow early intervention to minimize the consequences of ineffective cerebral tissue perfusion.

  11. A heterogeneous human tissue mimicking phantom for RF heating and MRI thermal monitoring verification.

    Science.gov (United States)

    Yuan, Yu; Wyatt, Cory; Maccarini, Paolo; Stauffer, Paul; Craciunescu, Oana; Macfall, James; Dewhirst, Mark; Das, Shiva K

    2012-04-07

    This paper describes a heterogeneous phantom that mimics a human thigh with a deep-seated tumor, for the purpose of studying the performance of radiofrequency (RF) heating equipment and non-invasive temperature monitoring with magnetic resonance imaging (MRI). The heterogeneous cylindrical phantom was constructed with an outer fat layer surrounding an inner core of phantom material mimicking muscle, tumor and marrow-filled bone. The component materials were formulated to have dielectric and thermal properties similar to human tissues. The dielectric properties of the tissue mimicking phantom materials were measured with a microwave vector network analyzer and impedance probe over the frequency range of 80-500 MHz and at temperatures of 24, 37 and 45 °C. The specific heat values of the component materials were measured using a differential scanning calorimeter over the temperature range of 15-55 °C. The thermal conductivity value was obtained from fitting the curves obtained from one-dimensional heat transfer measurement. The phantom was used to verify the operation of a cylindrical four-antenna annular phased array extremity applicator (140 MHz) by examining the proton resonance frequency shift (PRFS) thermal imaging patterns for various magnitude/phase settings (including settings to focus heating in tumors). For muscle and tumor materials, MRI was also used to measure T1/T2* values (1.5 T) and to obtain the slope of the PRFS phase change versus temperature change curve. The dielectric and thermal properties of the phantom materials were in close agreement to well-accepted published results for human tissues. The phantom was able to successfully demonstrate satisfactory operation of the tested heating equipment. The MRI-measured thermal distributions matched the expected patterns for various magnitude/phase settings of the applicator, allowing the phantom to be used as a quality assurance tool. Importantly, the material formulations for the various tissue types

  12. Monitoring the oxygenation of the preterm brain : What is there to gain?

    NARCIS (Netherlands)

    Alderliesten, T.

    2016-01-01

    Despite advances in perinatal care, preterm birth is still associated with adverse neurodevelopmental outcome, often caused by cerebral injury. The most common forms of cerebral injury are all associated with disturbances in cerebral oxygen and blood supply. Traditionally, infant wellbeing is

  13. Monitoring phthalates in the tissues of broiler chicks with feedstuffs different phthalate contents

    Directory of Open Access Journals (Sweden)

    Alžbeta Jarošová

    2010-01-01

    Full Text Available For the monitoring of distribution and accumulation of phthalic acid esters (PAE in animal tissues, samples of muscle, mesenteric fat (fat, skin and liver from broiler chicks ROSS 308 were used. The chicks were divided into 4 groups (50 chicks each. All the chicks were given commercial diets (complete feed, KKS for broiler chicks (starter – BR1; grower – BR2 and finisher – BR3. The experimental diets were supplemented with vegetable oil (RO with low (group N or high (group V phthalate contents, or animal fat with a high phthalate content (group Z. Neither the control diets (K, nor the grower (BR1 diets contained vegetable oils or animal fat. The N chicks were given the grower (BR2 and finisher (BR3 diets supplemented with 5% and 3% vegetable oil, respectively. The V chicks were given BR2 and BR3 diets with 5% and 3% vegetable oil, respectively. The Z chicks were given BR2 and BR3 diets with 5% and 3% animal fat, respectively. Di-n-butyl phthalate (DBP and di-(2-ethylhexyl phthalate (DEHP were found in the tissues of chicks in all the experimental groups. The DBP content in the muscle ranged from 0.03 to 0.55 mg . kg−1, in the adipose tissue from < 0.20 to 2.56 mg . kg−1, in the skin from < 0.20 to 1.49 mg . kg−1, and in the liver from 0.03 to 0.13 mg . kg−1. The content of DEHP in the muscle ranged from 0.03 to 1.15 mg . kg−1, in the adipose tissue from 0.25 to 9.85 mg . kg−1, in the skin from < 0.20 to 4.68 mg . kg−1, and in the liver from 0.16 to 0.24 mg . kg−1. The highest concentrations of DBP of 1.28 ± 1.00 mg . kg−1 of fresh sample (an average value from 8 chicks was determined in the adipose tissue of V chicks. The highest concentration of DEHP of 3.27 ± 2.87 mg . kg−1 of fresh sample (mean of 8 chicks was also determined in the V group. The accumulation of DEHP was 3.2; 2.6 and 2.9 times higher than that of DBP in the muscle, adipose tissue and skin

  14. Development and Characterization of Tissue Equivalent Proportional Counter for Radiation Monitoring in International Space Station

    Directory of Open Access Journals (Sweden)

    Uk-Won Nam

    2013-06-01

    Full Text Available Tissue equivalent proportional counter (TEPC can measure the Linear Energy Transfer (LET spectrum and calculate the equivalent dose for the complicated radiation field in space. In this paper, we developed and characterized a TEPC for radiation monitoring in International Space Station (ISS. The prototype TEPC which can simulate a 2 μm of the site diameter for micro-dosimetry has been tested with a standard alpha source (241Am, 5.5 MeV. Also, the calibration of the TEPC was performed by the 252Cf neutron standard source in Korea Research Institute of Standards and Science (KRISS. The determined calibration factor was kf = 3.59×10-7 mSv/R.

  15. Met-myoglobin formation, accumulation, degradation, and myoglobin oxygenation monitoring based on multiwavelength attenuance measurement in porcine meat

    Science.gov (United States)

    Nguyen, Thien; Phan, Kien Nguyen; Lee, Jee-Bum; Kim, Jae Gwan

    2016-05-01

    We propose a simple, rapid, and nondestructive method to investigate formation, accumulation, and degradation of met-myoglobin (met-Mb) and myoglobin oxygenation from the interior of porcine meat. For the experiment, color photos and attenuance spectra of porcine meat (well-bled muscle, fat, and mixed) were collected daily to perform colorimetric analysis and to obtain the differences of attenuance between 578 and 567 nm (A578-A567) and between 615 and 630 nm (A630-A615), respectively. Oxy-, deoxy-, and met-myoglobin concentration changes over storage time were also calculated using Beer-Lamberts' law with reflectance intensities at 557, 582, and 630 nm. The change of A578-A567 was well matched with the change of myoglobin oxygenation, and the change of A630-A615 corresponded well with the formation and degradation of met-Mb. In addition, attenuation differences, A578-A567 and A630-A615, were able to show the formation of met-Mb earlier than colorimetric analysis. Therefore, the attenuance differences between wavelengths can be indicators for estimating myoglobin oxygenation and met-Mb formation, accumulation, and degradation, which enable us to design a simple device to monitor myoglobin activities in porcine meat.

  16. The SafeBoosC Phase II Randomised Clinical Trial : A Treatment Guideline for Targeted Near-Infrared-Derived Cerebral Tissue Oxygenation versus Standard Treatment in Extremely Preterm Infants

    NARCIS (Netherlands)

    Pellicer, Adelina; Greisen, Gorm; Benders, Manon; Claris, Olivier; Dempsey, Eugene; Fumagalli, Monica; Gluud, Christian; Hagmann, Cornelia; Hellstroem-Westas, Lena; Hyttel-Sorensen, Simon; Lemmers, Petra; Naulaers, Gunnar; Pichler, Gerhard; Roll, Claudia; van Bel, Frank; van Oeveren, Wim; Skoog, Maria; Wolf, Martin; Austin, Topun

    2013-01-01

    Near-infrared spectroscopy-derived regional tissue oxygen saturation of haemoglobin (rSto(2)) reflects venous oxygen saturation. If cerebral metabolism is stable, rSto(2) can be used as an estimate of cerebral oxygen delivery. The SafeBoosC phase II randomised clinical trial hypothesises that the

  17. Tissue Oxygenation and Negative-Pressure Wound Therapy When Applied to the Feet of Persons With Diabetes Mellitus: An Observational Study.

    Science.gov (United States)

    Lee, Ye-Na; Lee, Jong Seok; Han, Seung-Kyu; Jung, Hye-Kyung

    Our group has reported that negative-pressure wound therapy (NPWT) decreases tissue oxygenation by 84% in the foot of diabetic patients because the pad of the connecting drainage tube and foam sponge of the NPWT system compress the wound bed. The purpose of this study was to determine whether an NPWT modified dressing application reduces tissue oxygenation in the feet of persons with diabetes mellitus. A prospective, clinical, observational study. We enrolled 30 patients with diabetic mellitus; their mean age was 63.9 ± 11.2 years (mean ± standard deviation). All were cared for at the diabetic wound center at an academic tertiary medical center in South Korea between 2014 and January 2015. Transcutaneous partial oxygen pressures (TcpO2) were measured to determine tissue oxygenation levels beneath modified NPWT dressings. A TcpO2 sensor was fixed at the tarsometatarsal area of the contralateral unwounded foot. A negative pressure of -125 mm Hg was applied until TcpO2 reached a plateau state; values were measured before, during, and after the modified NPWT. The Wilcoxon' and Mann-Whitney U tests were used to compare differences between these measurements. TcpO2 levels decreased by 26% during the modified NPWT. Mean TcpO2 values before, during, and after turning off the therapy were 54.3 ± 15.3 mm Hg, 41.6 ± 16.3 mm Hg, and 53.3 ± 15.6 mm Hg (P drainage tube significantly reduces the amount of tissue oxygenation loss beneath foam dressings on the skin of the foot dorsum in diabetic patients.

  18. Oxygen Mapping within Healthy and Acutely Infarcted Brain Tissue in Humans Using the NMR Relaxation of Lipids: A Proof-Of-Concept Translational Study.

    Science.gov (United States)

    Colliez, Florence; Safronova, Marta M; Magat, Julie; Joudiou, Nicolas; Peeters, André P; Jordan, Bénédicte F; Gallez, Bernard; Duprez, Thierry

    2015-01-01

    The clinical applicability of brain oxygenation mapping using the MOBILE (Mapping of Oxygen By Imaging Lipids relaxation Enhancement) magnetic resonance (MR) technique was assessed in the clinical setting of normal brain and of acute cerebral ischemia as a founding proof-of-concept translational study. Changes in the oxygenation level within healthy brain tissue can be detected by analyzing the spin-lattice proton relaxation ('Global T1' combining water and lipid protons) because of the paramagnetic properties of molecular oxygen. It was hypothesized that selective measurement of the relaxation of the lipid protons ('Lipids T1') would result in enhanced sensitivity of pO2 mapping because of higher solubility of oxygen in lipids than in water, and this was demonstrated in pre-clinical models using the MOBILE technique. In the present study, 12 healthy volunteers and eight patients with acute (48-72 hours) brain infarction were examined with the same clinical 3T MR system. Both Lipids R1 (R1 = 1/T1) and Global R1 were significantly different in the infarcted area and the contralateral unaffected brain tissue, with a higher statistical significance for Lipids R1 (median difference: 0.408 s-1; pbrain tissue of stroke patients were not significantly different from the R1 values calculated in the brain tissue of healthy volunteers. The main limitations of the present prototypic version of the MOBILE sequence are the long acquisition time (4 min), hampering robustness of data in uncooperative patients, and a 2 mm slice thickness precluding accurate measurements in small infarcts because of partial volume averaging effects.

  19. Tissue

    Directory of Open Access Journals (Sweden)

    David Morrissey

    2012-01-01

    Full Text Available Purpose. In vivo gene therapy directed at tissues of mesenchymal origin could potentially augment healing. We aimed to assess the duration and magnitude of transene expression in vivo in mice and ex vivo in human tissues. Methods. Using bioluminescence imaging, plasmid and adenoviral vector-based transgene expression in murine quadriceps in vivo was examined. Temporal control was assessed using a doxycycline-inducible system. An ex vivo model was developed and optimised using murine tissue, and applied in ex vivo human tissue. Results. In vivo plasmid-based transgene expression did not silence in murine muscle, unlike in liver. Although maximum luciferase expression was higher in muscle with adenoviral delivery compared with plasmid, expression reduced over time. The inducible promoter cassette successfully regulated gene expression with maximum levels a factor of 11 greater than baseline. Expression was re-induced to a similar level on a temporal basis. Luciferase expression was readily detected ex vivo in human muscle and tendon. Conclusions. Plasmid constructs resulted in long-term in vivo gene expression in skeletal muscle, in a controllable fashion utilising an inducible promoter in combination with oral agents. Successful plasmid gene transfection in human ex vivo mesenchymal tissue was demonstrated for the first time.

  20. Cerebral time domain-NIRS: Reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects

    OpenAIRE

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Rebecca, Re; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-01-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO2) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted ...

  1. Spectral filtering modulation method for estimation of hemoglobin concentration and oxygenation based on a single fluorescence emission spectrum in tissue phantoms.

    Science.gov (United States)

    Liu, Quan; Vo-Dinh, Tuan

    2009-10-01

    Hemoglobin concentration and oxygenation in tissue are important biomarkers that are useful in both research and clinical diagnostics of a wide variety of diseases such as cancer. The authors aim to develop simple ratiometric method based on the spectral filtering modulation (SFM) of fluorescence spectra to estimate the total hemoglobin concentration and oxygenation in tissue using only a single fluorescence emission spectrum, which will eliminate the need of diffuse reflectance measurements and prolonged data processing as required by most current methods, thus enabling rapid clinical measurements. The proposed method consists of two steps. In the first step, the total hemoglobin concentration is determined by comparing a ratio of fluorescence intensities at two emission wavelengths to a calibration curve. The second step is to estimate oxygen saturation by comparing a double ratio that involves three emission wavelengths to another calibration curve that is a function of oxygen saturation for known total hemoglobin concentration. Theoretical derivation shows that the ratio in the first step is linearly proportional to the total hemoglobin concentrations and the double ratio in the second step is related to both total hemoglobin concentration and hemoglobin oxygenation for the chosen fiber-optic probe geometry. Experiments on synthetic fluorescent tissue phantoms, which included hemoglobin with both constant and varying oxygenation as the absorber, polystyrene spheres as scatterers, and flavin adenine dinucleotide as the fluorophore, were carried out to validate the theoretical prediction. Tissue phantom experiments confirm that the ratio in the first step is linearly proportional to the total hemoglobin concentration and the double ratio in the second step is related to both total hemoglobin concentrations and hemoglobin oxygenation. Furthermore, the relations between the two ratios and the total hemoglobin concentration and hemoglobin oxygenation are insensitive

  2. Multi-channel electrical impedance tomography for regional tissue hydration monitoring

    International Nuclear Information System (INIS)

    Chen, Xiaohui; Kao, Tzu-Jen; Ashe, Jeffrey M; Boverman, Gregory; Sabatini, James E; Davenport, David M

    2014-01-01

    Poor assessment of hydration status during hemodialysis can lead to under- or over-hydration in patients with consequences of increased morbidity and mortality. In current practice, fluid management is largely based on clinical assessments to estimate dry weight (normal hydration body weight). However, hemodialysis patients usually have co-morbidities that can make the signs of fluid status ambiguous. Therefore, achieving normal hydration status remains a major challenge for hemodialysis therapy. Electrical impedance technology has emerged as a promising method for hydration monitoring due to its non-invasive nature, low cost and ease-of-use. Conventional electrical impedance-based hydration monitoring systems employ single-channel current excitation (either 2-electrode or 4-electrode methods) to perturb and extract averaged impedance from bulk tissue and use generalized models from large populations to derive hydration estimates. In the present study, a prototype, single-frequency electrical impedance tomography (EIT) system with simultaneous multi-channel current excitation was used to enable regional hydration change detection. We demonstrated the capability to detect a difference in daily impedance change between left leg and right leg in healthy human subjects, who wore a compression sock only on one leg to reduce daily gravitational fluid accumulation. The impedance difference corresponded well with the difference of lower leg volume change between left leg and right leg measured by volumetry, which on average is ∼35 ml, accounting for 0.7% of the lower leg volume. We have demonstrated the feasibility of using multi-channel EIT to extract hydration information in different tissue layers with minimal skin interference. Our simultaneous, multi-channel current excitation approach provides an effective method to separate electrode contact impedance and skin condition artifacts from hydration signals. The prototype system has the potential to be used in

  3. 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.

  4. Brain Oxygen Optimization in Severe Traumatic Brain Injury Phase-II: A Phase II Randomized Trial.

    Science.gov (United States)

    Okonkwo, David O; Shutter, Lori A; Moore, Carol; Temkin, Nancy R; Puccio, Ava M; Madden, Christopher J; Andaluz, Norberto; Chesnut, Randall M; Bullock, M Ross; Grant, Gerald A; McGregor, John; Weaver, Michael; Jallo, Jack; LeRoux, Peter D; Moberg, Dick; Barber, Jason; Lazaridis, Christos; Diaz-Arrastia, Ramon R

    2017-11-01

    A relationship between reduced brain tissue oxygenation and poor outcome following severe traumatic brain injury has been reported in observational studies. We designed a Phase II trial to assess whether a neurocritical care management protocol could improve brain tissue oxygenation levels in patients with severe traumatic brain injury and the feasibility of a Phase III efficacy study. Randomized prospective clinical trial. Ten ICUs in the United States. One hundred nineteen severe traumatic brain injury patients. Patients were randomized to treatment protocol based on intracranial pressure plus brain tissue oxygenation monitoring versus intracranial pressure monitoring alone. Brain tissue oxygenation data were recorded in the intracranial pressure -only group in blinded fashion. Tiered interventions in each arm were specified and impact on intracranial pressure and brain tissue oxygenation measured. Monitors were removed if values were normal for 48 hours consecutively, or after 5 days. Outcome was measured at 6 months using the Glasgow Outcome Scale-Extended. A management protocol based on brain tissue oxygenation and intracranial pressure monitoring reduced the proportion of time with brain tissue hypoxia after severe traumatic brain injury (0.45 in intracranial pressure-only group and 0.16 in intracranial pressure plus brain tissue oxygenation group; p injury after severe traumatic brain injury based on brain tissue oxygenation and intracranial pressure values was consistent with reduced mortality and increased proportions of patients with good recovery compared with intracranial pressure-only management; however, the study was not powered for clinical efficacy. Management of severe traumatic brain injury informed by multimodal intracranial pressure and brain tissue oxygenation monitoring reduced brain tissue hypoxia with a trend toward lower mortality and more favorable outcomes than intracranial pressure-only treatment. A Phase III randomized trial to assess

  5. Radiation-induced DNA damage in tumors and normal tissues. III. Oxygen dependence of the formation of strand breaks and DNA-protein crosslinks

    International Nuclear Information System (INIS)

    Zhang, H.; Wallen, C.A.; Wheeler, K.T.; Joch, C.J.

    1995-01-01

    Results from several laboratories, including ours, have suggested that measurements of radiation-induced DNA strand breaks and DNA-protein crosslinks (DPCs) may be used to estimate the hypoxic fraction or fractional hypoxic volume of tumors and normal tissues. This suggestion has been predicated on both published and nonpublished information that (1) the oxygen dependence of the formation of strand breaks in irradiated mammalian cells is similar to the oxygen dependence of radiation-produced cell killing, and (2) the oxygen dependence of the formation of DPCs in irradiated mammalian cells is the mirror image of the oxygen dependence of radiation-induced cell killing. However, the published studies that attempted to determine the relationship between the oxygen dependence of the formation of strand breaks and the radiation sensitivity of mammalian cells were not performed at 37 degrees C, the exact oxygen concentrations were not always known, and the results were conflicting. In addition, most of the data on the oxygen dependence of the formation of DPCs are unpublished. Consequently, we have undertaken a comprehensive investigation of one cell line, 9L/Ro rat brain tumor cells, to determine if the shape of the oxygen dependence curve and the K m value for radiation-induced strand breaks and DPCs were similar when 9L cells were irradiated under both ideal gas-liquid equilibrium conditions at 4 degrees C and nonideal gas-liquid equilibrium conditions at 37 degrees C. At 4 degrees C under ideal gas-liquid equilibrium conditions, the K m for the formation of strand breaks was approximately 0.0045 mM, and Km for radiation sensitivity was approximately 0.005mM. A similar comparison for the formation of DPCs at 4 degrees C could not be made, because the efficiency of the formation of DPC was much lower at 4 degrees C than at 37 degrees C. 30 refs., 3 figs

  6. Real time monitoring of pulsatile change in hemoglobin concentrations of cerebral tissue by a portable tissue oximeter with a 10-Hz sampling rate

    Science.gov (United States)

    Shiga, Toshikazu; Chihara, Eiichi; Tanabe, Kazuhisa; Tanaka, Yoshifumi; Yamamoto, Katsuyuki

    1998-01-01

    A portable CW tissue oximeter of a 10-Hz sampling rate was developed for examination of pulsatile components of the output signals as a mean of checking the signal reliability during long-term monitoring. Feasible studies were performed on a healthy subject. Changes in Hb and HbO2 signals of cerebral tissue were continuously measured by placing a photoprobe on the forehead during 6-hour sleep. Pulsatile changes in Hb and HbO2 were steadily observed over a whole period of the recording. The phase relation of pulsation in Hb and HbO2 was almost inverse. Not only information for reliable monitoring but also physiological parameters with respect to cerebral circulation and metabolism could be obtained by measuring the pulsatile components.

  7. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    International Nuclear Information System (INIS)

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-01-01

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ 0 /τ 100 (PL decay time τ at 0% O 2 /τ at 100% O 2 ) that is often used to express S

  8. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suprressed by X-irradiation

    International Nuclear Information System (INIS)

    Teplits, N.A.

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state. (E.T.)

  9. Oxygen consumption and cytochrome exidase activity of axolotl limbs muscle tissue in restoration of regenerative ability suppressed by X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Teplits, N A [AN SSSR, Moscow. Inst. Biologii Razvitiya

    1975-01-01

    The rate of oxygen use and activity of cytochrome oxidase in a homogenate of mitochondria and nuclei of muscle tissue of axolotl limbs after suppression of their regenerative capability by x irradiation and their restoration was studied experimentally. With suppression of the regenative capability the use of oxygen was depressed. Cytochrome oxidase activity in the homogenate and mitochondria decreased compared to that of the intact limb, in the nuclei of muscle tissue it was the same or greater. With restoration of the regenerative capability of the limbs the respiration rate of the homogenate and the mitochondria increased, accompanied by increased cytochrome oxidase activity. In the nuclei the cytochrome oxidase activity did not change in the blastema stage and sharply decreased in the limb formation state.

  10. Monitoring of organochlorine pesticide residue levels in adipose tissue of Veracruz, Mexico inhabitants.

    Science.gov (United States)

    Waliszewski, Stefan M; Caba, M; Herrero-Mercado, M; Saldariaga-Noreña, H; Meza, E; Zepeda, R; Martínez-Valenzuela, C; Infanzon, R; Hernández-Chalate, F

    2011-11-01

    The objective of the present study was to monitor the levels of organochlorine pesticides HCB, α-β-γ-HCH, pp'DDE, op'DDT and pp'DDT in 150 adipose tissue samples of Veracruz, Mexico inhabitants. In analyzed samples, the following pesticides were detected: p,p'-DDE in 100% of the samples at mean 1.643 mg/kg; p,p'-DDT in 99.3.% of the samples at mean 0.227 mg/kg; β-HCH in 97.3% of the samples at mean 0.063 mg/kg; and op'DDT in 93.3% of the samples at mean 0.022 mg/kg. Comparing mean, median and geometric mean concentrations of organochlorine pesticides shows a decrease in values from mean to median and to geometric mean which points out a prevalence of lower concentrations among the total samples and the existence of occasional cases of extreme exposure expressed in range values. The pooled samples divided according to sex, showed only significant differences of pp'DDE median concentrations between sexes. The other organochlorine pesticides indicated no statistical differences between sexes, including the pp'DDE/pp'DDT ratio. The samples grouped according to age, showed that the third tertile was more contaminated for both sexes, indicating age as a positively associated factor with organochlorine pesticide levels in adipose tissue of Veracruz inhabitants. Comparing organochlorine pesticide levels between 2008 and 2010 years, a decreased tendency for β-HCH, pp'DDE, Σ-DDT and pp'DDE/pp'DDT ratio levels was observed.

  11. Monitoring of interaction of low-frequency electric field with biological tissues upon optical clearing with optical coherence tomography.

    Science.gov (United States)

    Peña, Adrián F; Doronin, Alexander; Tuchin, Valery V; Meglinski, Igor

    2014-08-01

    The influence of a low-frequency electric field applied to soft biological tissues ex vivo at normal conditions and upon the topical application of optical clearing agents has been studied by optical coherence tomography (OCT). The electro-kinetic response of tissues has been observed and quantitatively evaluated by the double correlation OCT approach, utilizing consistent application of an adaptive Wiener filtering and Fourier domain correlation algorithm. The results show that fluctuations, induced by the electric field within the biological tissues are exponentially increased in time. We demonstrate that in comparison to impedance measurements and the mapping of the temperature profile at the surface of the tissue samples, the double correlation OCT approach is much more sensitive to the changes associated with the tissues' electro-kinetic response. We also found that topical application of the optical clearing agent reduces the tissues' electro-kinetic response and is cooling the tissue, thus reducing the temperature induced by the electric current by a few degrees. We anticipate that dcOCT approach can find a new application in bioelectrical impedance analysis and monitoring of the electric properties of biological tissues, including the resistivity of high water content tissues and its variations.

  12. Engineering zonal cartilaginous tissue by modulating oxygen levels and mechanical cues through the depth of infrapatellar fat pad stem cell laden hydrogels.

    Science.gov (United States)

    Luo, Lu; O'Reilly, Adam R; Thorpe, Stephen D; Buckley, Conor T; Kelly, Daniel J

    2017-09-01

    Engineering tissues with a structure and spatial composition mimicking those of native articular cartilage (AC) remains a challenge. This study examined if infrapatellar fat pad-derived stem cells (FPSCs) can be used to engineer cartilage grafts with a bulk composition and a spatial distribution of matrix similar to the native tissue. In an attempt to mimic the oxygen gradients and mechanical environment within AC, FPSC-laden hydrogels (either 2 mm or 4 mm in height) were confined to half of their thickness and/or subjected to dynamic compression (DC). Confining FPSC-laden hydrogels was predicted to accentuate the gradient in oxygen tension through the depth of the constructs (higher in the top and lower in the bottom), leading to enhanced glycosaminoglycan (GAG) and collagen synthesis in 2 mm high tissues. When subjected to DC alone, both GAG and collagen accumulation increased within 2 mm high unconfined constructs. Furthermore, the dynamic modulus of constructs increased from 0.96 MPa to 1.45 MPa following the application of DC. There was no synergistic benefit of coupling confinement and DC on overall levels of matrix accumulation; however in all constructs, irrespective of their height, the combination of these boundary conditions led to the development of engineered tissues that spatially best resembled native AC. The superficial region of these constructs mimicked that of native tissue, staining weakly for GAG, strongly for type II collagen, and in 4 mm high tissues more intensely for proteoglycan 4 (lubricin). This study demonstrated that FPSCs respond to joint-like environmental conditions by producing cartilage tissues mimicking native AC. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Influence of the depth of sedation on regional cerebral oxygen saturation monitoring in neurosurgery of supratentorial gliomas

    Directory of Open Access Journals (Sweden)

    ZHANG Kai⁃ying

    2012-12-01

    Full Text Available Objective To investigate the influence on regional cerebral oxygen saturation (rScO2 of sedation depth during anesthesia induction and maintenance in supratentorial glioma resections. Methods Thirty patients with Ⅰ - Ⅱ supratentorial glioma (graded by American Society of Anesthesiologists underwent elective supratentorial glioma resection were included in this study. Rocuronium, sufentanil and propofol were used for anesthesia induction. After trachea cannula, total intravenous anesthesia (TIVA was maintained with plasma concentration of propofol 2.80-3.20 μg/ml and remifentanil 0.10-0.20 μg/(kg·min. Thirty groups of rScO2, bispectral index (BIS, mean arterial pressure (MAP and heart rate (HR were recorded continuously till the incision. Results During anesthesia induction, BIS decreased along with the infusion of anesthetics, and there was significant negative correlation between BIS and rScO2 (r = ⁃0.803, P = 0.001. During anesthesia maintenance, rScO2 and BIS were not significantly related (r = 0.147, P = 0.396. Conclusion The rScO2 monitoring can reflect the influence of sedation depth on cerebral oxygen delivery and consumption balance during supratentorial glioma resection under TIVA.

  14. Extreme dissolved oxygen variability in urbanised tropical wetlands: The need for detailed monitoring to protect nursery ground values

    Science.gov (United States)

    Dubuc, Alexia; Waltham, Nathan; Malerba, Martino; Sheaves, Marcus

    2017-11-01

    Little is known about levels of dissolved oxygen fish are exposed to daily in typical urbanised tropical wetlands found along the Great Barrier Reef coastline. This study investigates diel dissolved oxygen (DO) dynamics in one of these typical urbanised wetlands, in tropical North Queensland, Australia. High frequency data loggers (DO, temperature, depth) were deployed for several days over the summer months in different tidal pools and channels that fish use as temporal or permanent refuges. DO was extremely variable over a 24 h cycle, and across the small-scale wetland. The high spatial and temporal DO variability measured was affected by time of day and tidal factors, namely water depth, tidal range and tidal direction (flood vs ebb). For the duration of the logging time, DO was mainly above the adopted threshold for hypoxia (50% saturation), however, for around 11% of the time, and on almost every logging day, DO values fell below the threshold, including a severe hypoxic event (nursery ground value. There is a substantial discontinuity between the recommended DO values in the Australian and New Zealand Guidelines for Fresh and Marine Water Quality and the values observed in this wetland, highlighting the limited value of these guidelines for management purposes. Local and regional high frequency data monitoring programs, in conjunction with local exposure risk studies are needed to underpin the development of the management that will ensure the sustainability of coastal wetlands.

  15. Oxygen Plasma Treatment on 3D-Printed Chitosan/Gelatin/Hydroxyapatite Scaffolds for Bone Tissue Engineering.

    Science.gov (United States)

    Lee, Chang-Min; Yang, Seong-Won; Jung, Sang-Chul; Kim, Byung-Hoon

    2017-04-01

    The 3D hydroxyapatite/gelatin/chitosan composite scaffolds were fabricated by 3D printing technique. The scaffolds were treated by oxygen plasma to improve the bioactivity and its surface characterization and in vitro cell culture were investigated. The scaffolds exhibited the good porosity and interconnectivity of pores. After oxygen plasma etching, roughness and wettability on the scaffolds surface are increased. Plasma treated scaffolds showed higher proliferation than that of untreated scaffolds. Oxygen plasma treatment could be used as potential tool to enhance the biocompatibility on the 3D composite scaffolds.

  16. Implementing an Oxygen Supplementation and Monitoring Protocol on Inpatient Pediatric Bronchiolitis: An Exercise in Deimplementation

    Directory of Open Access Journals (Sweden)

    Brian LeCleir

    2017-01-01

    Full Text Available Aim. Our goal in this study is to evaluate the effectiveness of our oxygen (O2 protocol to reduce length of stay (LOS for children hospitalized with bronchiolitis. Methods. In this retrospective cohort study, the outcomes of children ≤ 24 months old that were admitted with bronchiolitis and placed on the O2 protocol were compared to historical controls. The primary outcome was hospital length of stay. Secondary outcomes were duration of O2 supplementation, rates of pediatric intensive care unit transfer, and readmission. Results. Groups were not significantly different in age, gender, and rates of respiratory distress score assessment. Significantly more severely ill patients were in the O2 protocol group. There were no significant differences between control and O2 protocol groups with regard to mean LOS, rates of pediatric intensive care unit transfer, or seven-day readmission rates. By multiple regression analysis, the use of the O2 protocol was associated with a nearly 20% significant decrease in the length of hospitalization (p=0.030. Conclusion. Use of O2 supplementation protocol increased LOS in the more ill patients with bronchiolitis but decreased overall LOS by having a profound effect on patients with mild bronchiolitis.

  17. Electrochemical monitoring of native catalase activity in skin using skin covered oxygen electrode.

    Science.gov (United States)

    Nocchi, Sarah; Björklund, Sebastian; Svensson, Birgitta; Engblom, Johan; Ruzgas, Tautgirdas

    2017-07-15

    A skin covered oxygen electrode, SCOE, was constructed with the aim to study the enzyme catalase, which is part of the biological antioxidative system present in skin. The electrode was exposed to different concentrations of H 2 O 2 and the amperometric current response was recorded. The observed current is due to H 2 O 2 penetration through the outermost skin barrier (referred to as the stratum corneum, SC) and subsequent catalytic generation of O 2 by catalase present in the underlying viable epidermis and dermis. By tape-stripping the outermost skin layers we demonstrate that SC is a considerable diffusion barrier for H 2 O 2 penetration. Our experiments also indicate that skin contains a substantial amount of catalase, which is sufficient to detoxify H 2 O 2 that reaches the viable epidermis after exposure of skin to high concentrations of peroxide (0.5-1mM H 2 O 2 ). Further, we demonstrate that the catalase activity is reduced at acidic pH, as compared with the activity at pH 7.4. Finally, experiments with often used penetration enhancer thymol shows that this compound interferes with the catalase reaction. Health aspect of this is briefly discussed. Summarizing, the results of this work show that the SCOE can be utilized to study a broad spectrum of issues involving the function of skin catalase in particular, and the native biological antioxidative system in skin in general. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Towards real-time non contact spatial resolved oxygenation monitoring using a multi spectral filter array camera in various light conditions

    Science.gov (United States)

    Bauer, Jacob R.; van Beekum, Karlijn; Klaessens, John; Noordmans, Herke Jan; Boer, Christa; Hardeberg, Jon Y.; Verdaasdonk, Rudolf M.

    2018-02-01

    Non contact spatial resolved oxygenation measurements remain an open challenge in the biomedical field and non contact patient monitoring. Although point measurements are the clinical standard till this day, regional differences in the oxygenation will improve the quality and safety of care. Recent developments in spectral imaging resulted in spectral filter array cameras (SFA). These provide the means to acquire spatial spectral videos in real-time and allow a spatial approach to spectroscopy. In this study, the performance of a 25 channel near infrared SFA camera was studied to obtain spatial oxygenation maps of hands during an occlusion of the left upper arm in 7 healthy volunteers. For comparison a clinical oxygenation monitoring system, INVOS, was used as a reference. In case of the NIRS SFA camera, oxygenation curves were derived from 2-3 wavelength bands with a custom made fast analysis software using a basic algorithm. Dynamic oxygenation changes were determined with the NIR SFA camera and INVOS system at different regional locations of the occluded versus non-occluded hands and showed to be in good agreement. To increase the signal to noise ratio, algorithm and image acquisition were optimised. The measurement were robust to different illumination conditions with NIR light sources. This study shows that imaging of relative oxygenation changes over larger body areas is potentially possible in real time.

  19. In vivo monitoring of seeds and plant-tissue water absorption using optical coherence tomography and optical coherence microscopy

    Science.gov (United States)

    Sapozhnikova, Veronika V.; Kutis, Irina S.; Kutis, Sergey D.; Kuranov, Roman V.; Gelikonov, Grigory V.; Shabanov, Dmitry V.; Kamensky, Vladislav A.

    2004-07-01

    First experimental results on OCT imaging of internal structure of plant tissues and in situ OCT monitoring of plant tissue regeneration at different water supply are reported. Experiments for evaluating OCT capabilities were performed on Tradescantia. The investigation of seeds swelling was performed on wheat seeds (Triticum L.), barley seeds (Hordeum L.), long-fibred flax seeds (Linum usitatissimum L.) and cucumber seeds (Cucumis sativus L.). These OCT images correlate with standard microscopy data from the same tissue regions. Seeds were exposed to a low-intensity physical factor-the pulsed gradient magnetic field (GMF) with pulse duration 0.1 s and maximum amplitude 5 mT (4 successive pulses during 0.4 s). OCT and OCM enable effective monitoring of fast reactions in plants and seeds at different water supply.

  20. Modification of the radiation response of pig skin by manipulation of tissue oxygen tension using anesthetics and administration of BW12C

    International Nuclear Information System (INIS)

    van den Aardweg, G.J.; Hopewell, J.W.; Barnes, D.W.; Sansom, J.M.; Nethersell, A.B.

    1989-01-01

    The importance of tissue oxygen tension on radiosensitivity was studied by examining modifications in the incidence of moist desquamation in pig skin after irradiation with strontium-90 plaques. The effects were analyzed using quantal dose-response data and comparisons were made using ED50 values for moist desquamation. Under standard anesthetic conditions of 2% halothane, approximately 70% oxygen, and approximately 30% nitrous oxide, the ED50 value (+/- SE) for moist desquamation was 27.32 +/- 0.52 Gy with no significant variation in radiosensitivity between dorsal, lateral, and ventral skin sites on the flank. Irradiation with 2% halothane and air increased the ED50 to 31.25 +/- 0.94 Gy, primarily due to an increased radioresistance of the dorsal sites. When combined with BW12C, a drug which binds oxygen selectively to hemoglobin and hence reduced the oxygen availability to tissues, a further increase in the ED50 values was observed. This was approximately 39 Gy with BW12C concentrations of 30 mg/kg and 50 mg/kg b.w. of BW12C, indicating a dose modification factor (DMF) of approximately 1.26. However, when animals were breathing the standard gas mixture, this DMF was reduced to 1.15 for 30 mg/kg of BW12C, indicating that a higher level of oxygen partly counteracted the effects of the drug in these studies with BW12C. The greatest variability in radiosensitivity was seen in the dorsal fields. This suggested complex physiological adaptation, a phenomenon that might also explain the absence of any modification of the radiation response when 100 mg/kg of BW12C was used

  1. Monitoring Oxygen Levels in Orthotopic Human Glioma Xenograft Following Carbogen Inhalation and Chemotherapy by Implantable Resonator Based Oximetry

    Science.gov (United States)

    Hou, Huagang; Nemani, Venkata Krishnamurthy; Du, Gaixin; Montano, Ryan; Song, Rui; Gimi, Barjor; Swartz, Harold M.; Eastman, Alan; Khan, Nadeem

    2014-01-01

    Hypoxia is a critical hallmark of glioma, and significantly compromises treatment efficacy. Unfortunately, techniques for monitoring glioma pO2 to facilitate translational research are lacking. Furthermore, poor prognoses of patients with malignant glioma, in particular glioblastoma multiforme, warrant effective strategies that can inhibit hypoxia and improve treatment outcome. EPR oximetry using implantable resonators was implemented for monitoring pO2 in normal cerebral tissue and U251 glioma in mice. Breathing carbogen (95% O2 + 5% CO2) was tested for hyperoxia in the normal brain and glioma xenografts. A new strategy to inhibit glioma growth by rationally combining gemcitabine and MK-8776, a cell cycle checkpoint inhibitor, was also investigated. The mean pO2 of left and right hemisphere were approximately 56 – 69 mmHg in the normal cerebral tissue of mice. The mean baseline pO2 of U251 glioma on the first and fifth day of measurement was 21.9 ± 3.7 and 14.1 ± 2.4 mmHg, respectively. The mean brain pO2 including glioma increased by at least 100% on carbogen inhalation, although the response varied between the animals over days. Treatment with gemcitabine + MK-8776 significantly increased pO2 and inhibited glioma growth assessed by MRI. In conclusion, EPR oximetry with implantable resonators can be used to monitor the efficacy of carbogen inhalation and chemotherapy on orthotopic glioma in mice. The increase in glioma pO2 of mice breathing carbogen can be used to improve treatment outcome. The treatment with gemcitabine + MK-8776 is a promising strategy that warrants further investigation. PMID:25111969

  2. Monitoring oxygen levels in orthotopic human glioma xenograft following carbogen inhalation and chemotherapy by implantable resonator-based oximetry.

    Science.gov (United States)

    Hou, Huagang; Krishnamurthy Nemani, Venkata; Du, Gaixin; Montano, Ryan; Song, Rui; Gimi, Barjor; Swartz, Harold M; Eastman, Alan; Khan, Nadeem

    2015-04-01

    Hypoxia is a critical hallmark of glioma, and significantly compromises treatment efficacy. Unfortunately, techniques for monitoring glioma pO2 to facilitate translational research are lacking. Furthermore, poor prognosis of patients with malignant glioma, in particular glioblastoma multiforme, warrant effective strategies that can inhibit hypoxia and improve treatment outcome. EPR oximetry using implantable resonators was implemented for monitoring pO2 in normal cerebral tissue and U251 glioma in mice. Breathing carbogen (95% O2 + 5% CO2 ) was tested for hyperoxia in the normal brain and glioma xenografts. A new strategy to inhibit glioma growth by rationally combining gemcitabine and MK-8776, a cell cycle checkpoint inhibitor, was also investigated. The mean pO2 of left and right hemisphere were ∼56-69 mmHg in the normal cerebral tissue of mice. The mean baseline pO2 of U251 glioma on the first and fifth day of measurement was 21.9 ± 3.7 and 14.1 ± 2.4 mmHg, respectively. The mean brain pO2 including glioma increased by at least 100% on carbogen inhalation, although the response varied between the animals over days. Treatment with gemcitabine + MK-8776 significantly increased pO2 and inhibited glioma growth assessed by MRI. In conclusion, EPR oximetry with implantable resonators can be used to monitor the efficacy of carbogen inhalation and chemotherapy on orthotopic glioma in mice. The increase in glioma pO2 of mice breathing carbogen can be used to improve treatment outcome. The treatment with gemcitabine + MK-8776 is a promising strategy that warrants further investigation. © 2014 UICC.

  3. Integration of intracellular telomerase monitoring by electrochemiluminescence technology and targeted cancer therapy by reactive oxygen species.

    Science.gov (United States)

    Zhang, Huairong; Li, Binxiao; Sun, Zhaomei; Zhou, Hong; Zhang, Shusheng

    2017-12-01

    Cancer therapies based on reactive oxygen species (ROS) have emerged as promising clinical treatments. Electrochemiluminescence (ECL) technology has also attracted considerable attention in the field of clinical diagnosis. However, studies about the integration of ECL diagnosis and ROS cancer therapy are very rare. Here we introduce a novel strategy that employs ECL technology and ROS to fill the above vacancy. Briefly, an ITO electrode was electrodeposited with polyluminol-Pt NPs composite films and modified with aptamer DNA to capture HL-60 cancer cells with high specificity. After that, mesoporous silica nanoparticles (MSNs) filled with phorbol 12-myristate 13-acetate (PMA) were closed by the telomerase primer DNA (T-primer DNA) and aptamer. After aptamer on MSN@PMA recognized and combined with the HL-60 cancer cells with high specificity, T-primer DNA on MSN@PMA could be moved away from the MSN@PMA surface after extension by telomerase in the HL-60 cancer cells and PMA was released to induce the production of ROS by the HL-60 cancer cells. After that, the polyluminol-Pt NPs composite films could react with hydrogen peroxide (a major ROS) and generate an ECL signal. Thus the intracellular telomerase activity of the HL-60 cancer cells could be detected in situ . Besides, ROS could induce apoptosis in the HL-60 cancer cells with high efficacy by causing oxidative damage to the lipids, protein, and DNA. Above all, the designed platform could not only detect intracellular telomerase activity instead of that of extracted telomerase, but could also kill targeted tumors by ECL technology and ROS.

  4. Can systemically generated reactive oxygen species help to monitor disease activity in generalized vitiligo? A pilot study

    Directory of Open Access Journals (Sweden)

    Richeek Pradhan

    2014-01-01

    Full Text Available Background: Generalized vitiligo is a disease with unpredictable bursts of activity, goal of treatment during the active phase being to stabilize the lesions. This emphasizes the need for a prospective marker for monitoring disease activity to help decide the duration of therapy. Aims and Objectives: In the present study, we examined whether reactive oxygen species (ROS generated in erythrocytes can be translated into a marker of activity in vitiligo. Materials and Methods: Level of intracellular ROS was measured flow cytometrically in erythrocytes from venous blood of 21 patients with generalized vitiligo and 21 healthy volunteers using the probe dichlorodihydrofluorescein diacetate. Results: The levels of ROS differed significantly between patients and healthy controls, as well as between active versus stable disease groups. In the active disease group, ROS levels were significantly lower in those being treated with systemic steroids than those that were not. ROS levels poorly correlated with disease duration or body surface area involved. Conclusion: A long-term study based on these findings can be conducted to further validate the potential role of ROS in monitoring disease activity vitiligo.

  5. Partial Oxygen Pressure Affects the Expression of Prognostic Biomarkers HIF-1 Alpha, Ki67, and CK20 in the Microenvironment of Colorectal Cancer Tissue.

    Science.gov (United States)

    Zhang, Lirong; Hu, Yu; Xi, Ning; Song, Jie; Huang, Wenjing; Song, Shanshan; Liu, Yiting; Liu, Xianying; Xie, Yingjun

    2016-01-01

    Hypoxia is prognostically important in colorectal cancer (CRC) therapy. Partial oxygen pressure (pO 2 ) is an important parameter of hypoxia. The correlation between pO 2 levels and expression levels of prognostic biomarkers was measured in CRC tissues. Human CRC tissues were collected and pO 2 levels were measured by OxyLite. Three methods for tissue fixation were compared, including formalin, Finefix, and Finefix-plus-microwave. Immunohistochemistry (IHC) staining was conducted by using the avidin-biotin complex technique for detecting the antibodies to hypoxia inducible factor-1 (HIF-1) alpha, cytokeratin 20 (CK20), and cell proliferation factor Ki67. The levels of pO 2 were negatively associated with the size of CRC tissues. Finefix-plus-microwave fixation has the potential to replace formalin. Additionally, microwave treatment improved Finefix performance in tissue fixation and protein preservation. The percentage of positive cells and gray values of HIF-1 alpha, CK20, and Ki67 were associated with CRC development ( P < 0.05). The levels of pO 2 were positively related with the gray values of Ki67 and negatively related with the values of HIF-1 alpha and CK20 ( P < 0.05). Thus, the levels of microenvironmental pO 2 affect the expression of predictive biomarkers HIF-1 alpha, CK20, and Ki67 in the development of CRC tissues.

  6. Partial Oxygen Pressure Affects the Expression of Prognostic Biomarkers HIF-1 Alpha, Ki67, and CK20 in the Microenvironment of Colorectal Cancer Tissue

    Directory of Open Access Journals (Sweden)

    Lirong Zhang

    2016-01-01

    Full Text Available Hypoxia is prognostically important in colorectal cancer (CRC therapy. Partial oxygen pressure (pO2 is an important parameter of hypoxia. The correlation between pO2 levels and expression levels of prognostic biomarkers was measured in CRC tissues. Human CRC tissues were collected and pO2 levels were measured by OxyLite. Three methods for tissue fixation were compared, including formalin, Finefix, and Finefix-plus-microwave. Immunohistochemistry (IHC staining was conducted by using the avidin-biotin complex technique for detecting the antibodies to hypoxia inducible factor-1 (HIF-1 alpha, cytokeratin 20 (CK20, and cell proliferation factor Ki67. The levels of pO2 were negatively associated with the size of CRC tissues. Finefix-plus-microwave fixation has the potential to replace formalin. Additionally, microwave treatment improved Finefix performance in tissue fixation and protein preservation. The percentage of positive cells and gray values of HIF-1 alpha, CK20, and Ki67 were associated with CRC development (P<0.05. The levels of pO2 were positively related with the gray values of Ki67 and negatively related with the values of HIF-1 alpha and CK20 (P<0.05. Thus, the levels of microenvironmental pO2 affect the expression of predictive biomarkers HIF-1 alpha, CK20, and Ki67 in the development of CRC tissues.

  7. A role for iron and oxygen chemistry in preserving soft tissues, cells and molecules from deep time

    OpenAIRE

    Schweitzer, Mary H.; Zheng, Wenxia; Cleland, Timothy P.; Goodwin, Mark B.; Boatman, Elizabeth; Theil, Elizabeth; Marcus, Matthew A.; Fakra, Sirine C.

    2014-01-01

    The persistence of original soft tissues in Mesozoic fossil bone is not explained by current chemical degradation models. We identified iron particles (goethite-αFeO(OH)) associated with soft tissues recovered from two Mesozoic dinosaurs, using transmission electron microscopy, electron energy loss spectroscopy, micro-X-ray diffraction and Fe micro-X-ray absorption near-edge structure. Iron chelators increased fossil tissue immunoreactivity to multiple antibodies dramatically, suggesting a ro...

  8. Monitoring of the Gasoline Oxygenate MTBE and BTEX Compounds in Groundwater in Catalonia (Northeast Spain

    Directory of Open Access Journals (Sweden)

    J. Fraile

    2002-01-01

    Full Text Available Headspace (HS gas chromatography with flame ionisation detection (HS-GC-FID and purge and trap (P gas chromatography-mass spectrometry (P were used for the determination of methyl-tert-butyl ether (MTBE and benzene, toluene, and xylenes (BTEX in groundwater. In this work, we present the first data on the levels of MTBE and BTEX in different groundwater wells in the area of Catalonia (northeast Spain. This monitoring campaign corresponded to 28 groundwater wells that were located near petrol service stations, oil refinery storage tanks, and/or chemical industry at different locations of Catalonia during the period of 1998/1999. The levels of MTBE detected varied between 4—300 μg/l, but two sites had MTBE levels up to 3 and 13 mg/l. In many cases, the BTEX levels were below 1 μg/l, whereas 7 sites had levels varying from 19 μg/l up to 3 mg/l. Most of them were related to leakage from underground tanks in petrol service stations, while the remaining three corresponded respectively to chemical industrial pollution of undetermined origin and to a leak from high-ground petrol tanks in petrochemical refinery factories. The aquifers involved were constituted by detritus coarse materials, sands, and conglomerates. Piezometric levels were roughly comprised between 3 and 40 m, and permeability (K and transmissivity (T values were estimated from field measurements.

  9. In vitro study of 3D PLGA/n-HAp/β-TCP composite scaffolds with etched oxygen plasma surface modification in bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Roh, Hee-Sang [Department of Dental Materials, School of Dentistry, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452 (Korea, Republic of); Jung, Sang-Chul [Department of Environmental Engineering, Sunchon National University, 255 Jungang-ro, Sunchon 57922 (Korea, Republic of); Kook, Min-Suk [Department of Oral and Maxillofacial Surgery, School of Dentistry, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju 61186 (Korea, Republic of); Kim, Byung-Hoon, E-mail: kim5055@chosun.ac.kr [Department of Dental Materials, School of Dentistry, Chosun University, 309 Pilmun-daero, Dong-gu, Gwangju 61452 (Korea, Republic of)

    2016-12-01

    Highlights: • PLGA and PLGA/n-HAp/β-TCP scaffolds were successfully fabricated by 3D printing. • Oxygen plasma etching increases the wettability and surface roughness. • Bioceramics and oxygen plasma etching and could be used to improve the cell affinity. - Abstract: Three-dimensional (3D) scaffolds have many advantageous properties for bone tissue engineering application, due to its controllable properties such as pore size, structural shape and interconnectivity. In this study, effects on oxygen plasma surface modification and adding of nano-hydroxyapatite (n-HAp) and β-tricalcium phosphate (β-TCP) on the 3D PLGA/n-HAp/β-TCP scaffolds for improving preosteoblast cell (MC3T3-E1) adhesion, proliferation and differentiation were investigated. The 3D PLGA/n-HAp/β-TCP scaffolds were fabricated by 3D Bio-Extruder equipment. The 3D scaffolds were prepared with 0°/90° architecture and pore size of approximately 300 μm. In addition 3D scaffolds surface were etched by oxygen plasma to enhance the hydrophilic property and surface roughness. After oxygen plasma treatment, the surface chemistry and morphology were investigated by Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. And also hydrophilic property was measured by contact angle. The MC3T3-E1 cell proliferation and differentiation were investigated by MTT assay and ALP activity. In present work, the 3D PLGA/HAp/beta-TCP composite scaffold with suitable structure for the growth of osteoblast cells was successfully fabricated by 3D rapid prototyping technique. The surface hydrophilicity and roughness of 3D scaffold increased by oxygen plasma treatment had a positive effect on cell adhesion, proliferation, and differentiation. Furthermore, the differentiation of MC3T3-E1 cell was significantly enhanced by adding of n-HAp and β-TCP on 3D PLGA scaffold. As a result, combination of bioceramics and oxygen plasma treatment showed a synergistic effect on

  10. Developing a Customized Perfusion Bioreactor Prototype with Controlled Positional Variability in Oxygen Partial Pressure for Bone and Cartilage Tissue Engineering.

    Science.gov (United States)

    Lee, Poh Soo; Eckert, Hagen; Hess, Ricarda; Gelinsky, Michael; Rancourt, Derrick; Krawetz, Roman; Cuniberti, Gianaurelio; Scharnweber, Dieter

    2017-05-01

    Skeletal development is a multistep process that involves the complex interplay of multiple cell types at different stages of development. Besides biochemical and physical cues, oxygen tension also plays a pivotal role in influencing cell fate during skeletal development. At physiological conditions, bone cells generally reside in a relatively oxygenated environment whereas chondrocytes reside in a hypoxic environment. However, it is technically challenging to achieve such defined, yet diverse oxygen distribution on traditional in vitro cultivation platforms. Instead, engineered osteochondral constructs are commonly cultivated in a homogeneous, stable environment. In this study, we describe a customized perfusion bioreactor having stable positional variability in oxygen tension at defined regions. Further, engineered collagen constructs were coaxed into adopting the shape and dimensions of defined cultivation platforms that were precasted in 1.5% agarose bedding. After cultivating murine embryonic stem cells that were embedded in collagen constructs for 50 days, mineralized constructs of specific dimensions and a stable structural integrity were achieved. The end-products, specifically constructs cultivated without chondroitin sulfate A (CSA), showed a significant increase in mechanical stiffness compared with their initial gel-like constructs. More importantly, the localization of osteochondral cell types was specific and corresponded to the oxygen tension gradient generated in the bioreactor. In addition, CSA in complementary with low oxygen tension was also found to be a potent inducer of chondrogenesis in this system. In summary, we have demonstrated a customized perfusion bioreactor prototype that is capable of generating a more dynamic, yet specific cultivation environment that could support propagation of multiple osteochondral lineages within a single engineered construct in vitro. Our system opens up new possibilities for in vitro research on human

  11. Monitoring Dynamic Interactions between Breast Cancer Cells and Human Bone Tissue in a Co-Culture Model

    Science.gov (United States)

    Contag, Christopher H.; Lie, Wen-Rong; Bammer, Marie C.; Hardy, Jonathan W.; Schmidt, Tobi L.; Maloney, William J.; King, Bonnie L.

    2015-01-01

    Purpose Bone is a preferential site of breast cancer metastasis and models are needed to study this process at the level of the microenvironment. We have used bioluminescence imaging (BLI) and multiplex biomarker immunoassays to monitor dynamic breast cancer cell behaviors in co-culture with human bone tissue. Procedures Femur tissue fragments harvested from hip replacement surgeries were co-cultured with luciferase-positive MDA-MB-231-fLuc cells. BLI was performed to quantify breast cell division and track migration relative to bone tissue. Breast cell colonization of bone tissues was assessed with immunohistochemistry. Biomarkers in co-culture supernatants were profiled with MILLIPLEX® immunoassays. Results BLI demonstrated increased MDA-MB-231-fLuc proliferation (pbones, and revealed breast cell migration toward bone. Immunohistochemistry illustrated MDA-MB-231-fLuc colonization of bone, and MILLIPLEX® profiles of culture supernatants suggested breast/bone crosstalk. Conclusions Breast cell behaviors that facilitate metastasis occur reproducibly in human bone tissue co-cultures and can be monitored and quantified using BLI and multiplex immunoassays. PMID:24008275

  12. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: Simultaneous oxygen and pH monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Rui; Xiao, Teng; Cui, Weipan [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Joseph, E-mail: jshinar@iastate.edu [Ames Laboratory-USDOE and Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Shinar, Ruth, E-mail: rshinar@iastate.edu [Microelectronics Research Center and Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2013-05-17

    Graphical abstract: -- Highlights: •Novel simply-fabricated all-organic electronics pH and oxygen optical monitor. •Excitation sources: directionally emitting, narrowed multicolor microcavity OLEDs. •Photodetectors: small molecule- or polymer-based with selective spectral responses. •Sensor film: structured high molecular weight polystyrene:polyethylene glycol blend. •×1.9 sensitivity enhancement and ×2.7 increase in the photoluminescence for oxygen. -- Abstract: Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs’ broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ∼20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ{sub 0}/τ{sub 100} (PL decay time τ at 0% O{sub 2}/τ at 100% O{sub 2}) that is often used

  13. Monitoring of temperature-mediated phase transitions of adipose tissue by combined optical coherence tomography and Abbe refractometry.

    Science.gov (United States)

    Yanina, Irina Y; Popov, Alexey P; Bykov, Alexander V; Meglinski, Igor V; Tuchin, Valery V

    2018-01-01

    Observation of temperature-mediated phase transitions between lipid components of the adipose tissues has been performed by combined use of the Abbe refractometry and optical coherence tomography. The phase transitions of the lipid components were clearly observed in the range of temperatures from 24°C to 60°C, and assessed by quantitatively monitoring the changes of the refractive index of 1- to 2-mm-thick porcine fat tissue slices. The developed approach has a great potential as an alternative method for obtaining accurate information on the processes occurring during thermal lipolysis. (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

  14. A role for iron and oxygen chemistry in preserving soft tissues, cells and molecules from deep time.

    Science.gov (United States)

    Schweitzer, Mary H; Zheng, Wenxia; Cleland, Timothy P; Goodwin, Mark B; Boatman, Elizabeth; Theil, Elizabeth; Marcus, Matthew A; Fakra, Sirine C

    2014-01-22

    The persistence of original soft tissues in Mesozoic fossil bone is not explained by current chemical degradation models. We identified iron particles (goethite-αFeO(OH)) associated with soft tissues recovered from two Mesozoic dinosaurs, using transmission electron microscopy, electron energy loss spectroscopy, micro-X-ray diffraction and Fe micro-X-ray absorption near-edge structure. Iron chelators increased fossil tissue immunoreactivity to multiple antibodies dramatically, suggesting a role for iron in both preserving and masking proteins in fossil tissues. Haemoglobin (HB) increased tissue stability more than 200-fold, from approximately 3 days to more than two years at room temperature (25°C) in an ostrich blood vessel model developed to test post-mortem 'tissue fixation' by cross-linking or peroxidation. HB-induced solution hypoxia coupled with iron chelation enhances preservation as follows: HB + O2 > HB - O2 > -O2 > +O2. The well-known O2/haeme interactions in the chemistry of life, such as respiration and bioenergetics, are complemented by O2/haeme interactions in the preservation of fossil soft tissues.

  15. The role of UCP 1 in production of reactive oxygen species by mitochondria isolated from brown adipose tissue

    Czech Academy of Sciences Publication Activity Database

    Dlasková, Andrea; Clarke, K.J.; Porter, R. K.

    2010-01-01

    Roč. 1797, č. 8 (2010), s. 1470-1476 ISSN 0005-2728 Institutional research plan: CEZ:AV0Z50110509 Keywords : Mitochondria * Reactive oxygen species * Uncoupling protein 1 Subject RIV: ED - Physiology Impact factor: 5.132, year: 2010

  16. Comparing CT perfusion with oxygen partial pressure in a rabbit VX2 soft-tissue tumor model.

    Science.gov (United States)

    Sun, Chang-Jin; Li, Chao; Lv, Hai-Bo; Zhao, Cong; Yu, Jin-Ming; Wang, Guang-Hui; Luo, Yun-Xiu; Li, Yan; Xiao, Mingyong; Yin, Jun; Lang, Jin-Yi

    2014-01-01

    The aim of this study was to evaluate the oxygen partial pressure of the rabbit model of the VX2 tumor using a 64-slice perfusion CT and to compare the results with that obtained using the oxygen microelectrode method. Perfusion CT was performed for 45 successfully constructed rabbit models of a VX2 brain tumor. The perfusion values of the brain tumor region of interest, the blood volume (BV), the time to peak (TTP) and the peak enhancement intensity (PEI) were measured. The results were compared with the partial pressure of oxygen (PO2) of that region of interest obtained using the oxygen microelectrode method. The perfusion values of the brain tumor region of interest in 45 successfully constructed rabbit models of a VX2 brain tumor ranged from 1.3-127.0 (average, 21.1 ± 26.7 ml/min/ml); BV ranged from 1.2-53.5 ml/100g (average, 22.2 ± 13.7 ml/100g); PEI ranged from 8.7-124.6 HU (average, 43.5 ± 28.7 HU); and TTP ranged from 8.2-62.3 s (average, 38.8 ± 14.8 s). The PO2 in the corresponding region ranged from 0.14-47 mmHg (average, 16 ± 14.8 mmHg). The perfusion CT positively correlated with the tumor PO2, which can be used for evaluating the tumor hypoxia in clinical practice.

  17. Novel diffuse optics system for continuous tissue viability monitoring: extended recovery in vivo testing in a porcine flap model

    Science.gov (United States)

    Lee, Seung Yup; Pakela, Julia M.; Hedrick, Taylor L.; Vishwanath, Karthik; Helton, Michael C.; Chung, Yooree; Kolodziejski, Noah J.; Stapels, Christopher J.; McAdams, Daniel R.; Fernandez, Daniel E.; Christian, James F.; O'Reilly, Jameson; Farkas, Dana; Ward, Brent B.; Feinberg, Stephen E.; Mycek, Mary-Ann

    2017-02-01

    In reconstructive surgery, tissue perfusion/vessel patency is critical to the success of microvascular free tissue flaps. Early detection of flap failure secondary to compromise of vascular perfusion would significantly increase the chances of flap salvage. We have developed a compact, clinically-compatible monitoring system to enable automated, minimally-invasive, continuous, and quantitative assessment of flap viability/perfusion. We tested the system's continuous monitoring capability during extended non-recovery surgery using an in vivo porcine free flap model. Initial results indicated that the system could assess flap viability/perfusion in a quantitative and continuous manner. With proven performance, the compact form constructed with cost-effective components would make this system suitable for clinical translation.

  18. Detection and Characterization of Reactive Oxygen and Nitrogen Species in Biological Systems by Monitoring Species-Specific Products.

    Science.gov (United States)

    Hardy, Micael; Zielonka, Jacek; Karoui, Hakim; Sikora, Adam; Michalski, Radosław; Podsiadły, Radosław; Lopez, Marcos; Vasquez-Vivar, Jeannette; Kalyanaraman, Balaraman; Ouari, Olivier

    2018-05-20

    Since the discovery of the superoxide dismutase enzyme, the generation and fate of short-lived oxidizing, nitrosating, nitrating, and halogenating species in biological systems has been of great interest. Despite the significance of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in numerous diseases and intracellular signaling, the rigorous detection of ROS and RNS has remained a challenge. Recent Advances: Chemical characterization of the reactions of selected ROS and RNS with electron paramagnetic resonance (EPR) spin traps and fluorescent probes led to the establishment of species-specific products, which can be used for specific detection of several forms of ROS and RNS in cell-free systems and in cultured cells in vitro and in animals in vivo. Profiling oxidation products from the ROS and RNS probes provides a rigorous method for detection of those species in biological systems. Formation and detection of species-specific products from the probes enables accurate characterization of the oxidative environment in cells. Measurement of the total signal (fluorescence, chemiluminescence, etc.) intensity does not allow for identification of the ROS/RNS formed. It is critical to identify the products formed by using chromatographic or other rigorous techniques. Product analyses should be accompanied by monitoring of the intracellular probe level, another factor controlling the yield of the product(s) formed. More work is required to characterize the chemical reactivity of the ROS/RNS probes, and to develop new probes/detection approaches enabling real-time, selective monitoring of the specific products formed from the probes. Antioxid. Redox Signal. 28, 1416-1432.

  19. Peripheral tissue oximetry

    DEFF Research Database (Denmark)

    Hyttel-Sorensen, Simon; Hessel, Trine Witzner; Greisen, Gorm

    2014-01-01

    Estimation of regional tissue oxygenation (rStO2) by near infrared spectroscopy enables non-invasive end-organ oxygen balance monitoring and could be a valuable tool in intensive care. However, the diverse absolute values and dynamics of different devices, and overall poor repeatability of measur......Estimation of regional tissue oxygenation (rStO2) by near infrared spectroscopy enables non-invasive end-organ oxygen balance monitoring and could be a valuable tool in intensive care. However, the diverse absolute values and dynamics of different devices, and overall poor repeatability......, and response to changing oxygenation by the down slope of rStO2 during vascular occlusion in the respective arm. 10 healthy adults, 21-29 years old, with double skinfolds on the forearm less than 10 mm participated. The median rStO2 was 70.7% (interquartile range (IQR) 7.7%), 68.4% (IQR 8.4%), and 64.6% (IQR 4...

  20. Using radionuclide imaging for monitoring repairment of bone defect with tissue-engineered bone graft in rabbits

    International Nuclear Information System (INIS)

    Xia Changsuo; Ye Fagang; Zou Yunwen; Ji Shixiang; Wang Dengchun

    2004-01-01

    Objective: To observe the effect of tissue-engineered bone grafts in repairing bone defect in rabbits, and assess the value of radionuclide for monitoring the therapeutic effect of this approach. Methods: Bilateral radial defects of 15 mm in length in 24 rabbits were made. The tissue-engineered bone grafts (composite graft) contained bone marrow stromal cells (BMSCs) of rabbits and calcium phosphate cement (CPC) were grafted in left side defects, CPC only grafts (artificial bone graft) in right defects. After the operation, radionuclide was used to monitor the therapeutic effects at 4, 8 and 12 weeks. Results: 99 Tc m -methylene diphosphonic acid (MDP) radionuclide bone imaging indicated that there was more radionuclide accumulation in grafting region of composite than that of CPC. There was significant difference between 99 Tc m -MDP uptake of the region of interest (ROI) and scintillant counts of composite bone and the artificial bone (P<0.01). Conclusion: Tissue-engineered bone grafts is eligible for repairing radial bone defects, and radionuclide imaging may accurately monitor the revascularization and bone regeneration after the bone graft implantation. (authors)

  1. Intra-operative tissue oxygen tension is increased by local insufflation of humidified-warm CO2 during open abdominal surgery in a rat model.

    Directory of Open Access Journals (Sweden)

    Jean K Marshall

    Full Text Available Maintenance of high tissue oxygenation (PtO2 is recommended during surgery because PtO2 is highly predictive of surgical site infection and colonic anastomotic leakage. However, surgical site perfusion is often sub-optimal, creating an obstructive hurdle for traditional, systemically applied therapies to maintain or increase surgical site PtO2. This research tested the hypothesis that insufflation of humidified-warm CO2 into the abdominal cavity would increase sub-peritoneal PtO2 during open abdominal surgery.15 Wistar rats underwent laparotomy under general anesthesia. Three sets of randomized cross-over experiments were conducted in which the abdominal cavity was subjected to alternating exposure to 1 humidified-warm CO2 & ambient air; 2 humidified-warm CO2 & dry-cold CO2; and 3 dry-cold CO2 & ambient air. Sub-peritoneal PtO2 and tissue temperature were measured with a polarographic oxygen probe.Upon insufflation of humidified-warm CO2, PtO2 increased by 29.8 mmHg (SD 13.3; p<0.001, or 96.6% (SD 51.9, and tissue temperature by 3.0°C (SD 1.7 p<0.001, in comparison with exposure to ambient air. Smaller, but significant, increases in PtO2 were seen in experiments 2 and 3. Tissue temperature decreased upon exposure to dry-cold CO2 compared with ambient air (-1.4°C, SD 0.5, p = 0.001.In a rat model, insufflation of humidified-warm CO2 into the abdominal cavity during open abdominal surgery causes an immediate and potentially clinically significant increase in PtO2. The effect is an additive result of the delivery of CO2 and avoidance of evaporative cooling via the delivery of the CO2 gas humidified at body temperature.

  2. A thermal monitoring sheet with low influence from adjacent waterbolus for tissue surface thermometry during clinical hyperthermia.

    Science.gov (United States)

    Arunachalam, Kavitha; Maccarini, Paolo F; Stauffer, Paul R

    2008-10-01

    This paper presents a complete thermal analysis of a novel conformal surface thermometer design with directional sensitivity for real-time temperature monitoring during hyperthermia treatments of large superficial cancer. The thermal monitoring sheet (TMS) discussed in this paper consists of a 2-D array of fiberoptic sensors embedded between two layers of flexible, low-loss, and thermally conductive printed circuit board (PCB) film. Heat transfer across all interfaces from the tissue surface through multiple layers of insulating dielectrics surrounding the small buried temperature sensor and into an adjacent temperature-regulated water coupling bolus was studied using 3-D thermal simulation software. Theoretical analyses were carried out to identify the most effective differential TMS probe configuration possible with commercially available flexible PCB materials and to compare their thermal responses with omnidirectional probes commonly used in clinical hyperthermia. A TMS sensor design that employs 0.0508-mm Kapton MTB and 0.2032-mm Kapton HN flexible polyimide films is proposed for tissue surface thermometry with low influence from the adjacent waterbolus. Comparison of the thermal simulations with clinical probes indicates the new differential TMS probe design to outperform in terms of both transient response and steady-state accuracy in selectively reading the tissue surface temperature, while decreasing the overall thermal barrier of the probe between the coupling waterbolus and tissue surface.

  3. Comparing CT perfusion with oxygen partial pressure in a rabbit VX2 soft-tissue tumor model

    International Nuclear Information System (INIS)

    Sun Changjin; Li Chao; Lv Haibo

    2014-01-01

    The aim of this study was to evaluate the oxygen partial pressure of the rabbit model of the VX2 tumor using a 64-slice perfusion CT and to compare the results with that obtained using the oxygen microelectrode method. Perfusion CT was performed for 45 successfully constructed rabbit models of a VX2 brain tumor. The perfusion values of the brain tumor region of interest, the blood volume (BV), the time to peak (TTP) and the peak enhancement intensity (PEI) were measured. The results were compared with the partial pressure of oxygen (PO2) of that region of interest obtained using the oxygen microelectrode method. The perfusion values of the brain tumor region of interest in 45 successfully constructed rabbit models of a VX2 brain tumor ranged from 1.3–127.0 (average, 21.1 ± 26.7 ml/min/ml); BV ranged from 1.2–53.5 ml/100g (average, 22.2 ± 13.7 ml/100g); PEI ranged from 8.7–124.6 HU (average, 43.5 ± 28.7 HU); and TTP ranged from 8.2–62.3 s (average, 38.8 ± 14.8 s). The PO2 in the corresponding region ranged from 0.14–47 mmHg (average, 16 ± 14.8 mmHg). The perfusion CT positively correlated with the tumor PO2, which can be used for evaluating the tumor hypoxia in clinical practice. (author)

  4. In vivo monitoring laser tissue interaction using high resolution Fourier-domain optical coherence tomography

    Science.gov (United States)

    Jo, Hang Chan; Shin, Dong Jun; Ahn, Jin-Chul; Chung, Phil-Sang; Kim, DaeYu

    2017-02-01

    Laser-induced therapies include laser ablation to remove or cut target tissue by irradiating high-power focused laser beam. These laser treatments are widely used tools for minimally invasive surgery and retinal surgical procedures in clinical settings. In this study, we demonstrate laser tissue interaction images of various sample tissues using high resolution Fourier-domain optical coherence tomography (Fd-OCT). We use a Q-switch diode-pumped Nd:YVO4 nanosecond laser (532nm central wavelength) with a 4W maximum output power at a 20 kHz repetition rate to ablate in vitro and in vivo samples including chicken breast and mouse ear tissues. The Fd-OCT system acquires time-series Bscan images at the same location during the tissue ablation experiments with 532nm laser irradiation. The real-time series of OCT cross-sectional (B-scan) images compare structural changes of 532nm laser ablation using same and different laser output powers. Laser tissue ablation is demonstrated by the width and the depth of the tissue ablation from the B-scan images.

  5. In vitro terahertz monitoring of muscle tissue dehydration under the action of hyperosmotic agents

    Energy Technology Data Exchange (ETDEWEB)

    Kolesnikov, A S; Kolesnikova, E A; Popov, A P; Tuchin, V V [N.G. Chernyshevsky Saratov State University, Saratov (Russian Federation); Nazarov, M M [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation); Shkurinov, A P [International Laser Center, M. V. Lomonosov Moscow State University, Moscow (Russian Federation)

    2014-07-31

    Dehydration of muscle tissue in vitro under the action of biologically compatible hyperosmotic agents is studied using a laser terahertz spectrometer in the frequency range from 0.25 to 2.5 THz. Broadband terahertz absorption and reflection spectra of the bovine skeletal muscle tissue were obtained under the action of glycerol, polyethylene glycol with the molecular weight 600 (PEG-600), and propylene glycol. The presented results are proposed for application in developing the methods of image contrast enhancement and increasing the depth of biological tissue probing with terahertz radiation. (laser biophotonics)

  6. Multiple approaches for enhancing all-organic electronics photoluminescent sensors: simultaneous oxygen and pH monitoring.

    Science.gov (United States)

    Liu, Rui; Xiao, Teng; Cui, Weipan; Shinar, Joseph; Shinar, Ruth

    2013-05-17

    Key issues in using organic light emitting diodes (OLEDs) as excitation sources in structurally integrated photoluminescence (PL)-based sensors are the low forward light outcoupling, the OLEDs' broad electroluminescence (EL) bands, and the long-lived remnant EL that follows an EL pulse. The outcoupling issue limits the detection sensitivity (S) as only ~20% of the light generated within standard OLEDs can be forward outcoupled and used for sensor probe excitation. The EL broad band interferes with the analyte-sensitive PL, leading to a background that reduces S and dynamic range. In particular, these issues hinder designing compact sensors, potentially miniaturizable, that are devoid of optical filters and couplers. We address these shortcomings by introducing easy-to-employ multiple approaches for outcoupling improvement, PL enhancement, and background EL reduction leading to novel, compact all-organic device architectures demonstrated for simultaneous monitoring of oxygen and pH. The sensor comprises simply-fabricated, directionally-emitting, narrower-band, multicolor microcavity OLED excitation and small molecule- and polymer-based organic photodetectors (OPDs) with a more selective spectral response. Additionally, S and PL intensity for oxygen are enhanced by using polystyrene (PS):polyethylene glycol (PEG) blends as the sensing film matrix. By utilizing higher molecular weight PS, the ratio τ0/τ100 (PL decay time τ at 0% O2/τ at 100% O2) that is often used to express S increases ×1.9 to 20.7 relative to the lower molecular weight PS, where this ratio is 11.0. This increase reduces to ×1.7 when the PEG is added (τ0/τ100=18.2), but the latter results in an increase ×2.7 in the PL intensity. The sensor's response time is <10s in all cases. The microporous structure of these blended films, with PEG decorating PS pores, serves a dual purpose. It results in light scattering that reduces the EL that is waveguided in the substrate of the OLEDs and

  7. In situ monitoring of localized shear stress and fluid flow within developing tissue constructs by Doppler optical coherence tomography

    Science.gov (United States)

    Jia, Yali; Bagnaninchi, Pierre O.; Wang, Ruikang K.

    2008-02-01

    Mechanical stimuli can be introduced to three dimensional (3D) cell cultures by use of perfusion bioreactor. Especially in musculoskeletal tissues, shear stress caused by fluid flow generally increase extra-cellular matrix (ECM) production and cell proliferation. The relationship between the shear stress and the tissue development in situ is complicated because of the non-uniform pore distribution within the cell-seeded scaffold. In this study, we firstly demonstrated that Doppler optical coherence tomography (DOCT) is capable of monitoring localized fluid flow and shear stress in the complex porous scaffold by examining their variation trends at perfusion rate of 5, 8, 10 and 12 ml/hr. Then, we developed the 3D porous cellular constructs, cell-seeded chitosan scaffolds monitored during several days by DOCT. The fiber based fourier domain DOCT employed a 1300 nm superluminescent diode with a bandwidth of 52 nm and a xyz resolution of 20×20×15 μm in free space. This setup allowed us not only to assess the cell growth and ECM deposition by observing their different scattering behaviors but also to further investigate how the cell attachment and ECM production has the effect on the flow shear stress and the relationship between flow rate and shear stress in the developing tissue construct. The possibility to monitor continuously the constructs under perfusion will easily indicate the effect of flow rate or shear stress on the cell viability and cell proliferation, and then discriminate the perfusion parameters affecting the pre-tissue formation rate growth.

  8. Calcium isotope fractionation between soft and mineralized tissues as a monitor of calcium use in vertebrates

    Science.gov (United States)

    Skulan, Joseph; DePaolo, Donald J.

    1999-01-01

    Calcium from bone and shell is isotopically lighter than calcium of soft tissue from the same organism and isotopically lighter than source (dietary) calcium. When measured as the 44Ca/40Ca isotopic ratio, the total range of variation observed is 5.5‰, and as much as 4‰ variation is found in a single organism. The observed intraorganismal calcium isotopic variations and the isotopic differences between tissues and diet indicate that isotopic fractionation occurs mainly as a result of mineralization. Soft tissue calcium becomes heavier or lighter than source calcium during periods when there is net gain or loss of mineral mass, respectively. These results suggest that variations of natural calcium isotope ratios in tissues may be useful for assessing the calcium and mineral balance of organisms without introducing isotopic tracers. PMID:10570137

  9. Micro fluidic System for Culturing and Monitoring of Neuronal Cells and Tissue

    DEFF Research Database (Denmark)

    Bakmand, Tanya; Waagepetersen, Helle S.

    The aim of this Ph.D. project was to combine experience within cell and tissue culturing, electrochemistry and microfabrication in order to develop an in vivo-like fluidic culturing platform, challenging the traditional culturing methods. The first goal was to develope a fluidic system for cultur...... with mass production. The last part of this thesis also includes perspectives on how to expand the latest designed device to facilitate culturing of tissue and co-culturing of cells....

  10. The Effect of Active versus Passive Recovery Periods during High Intensity Intermittent Exercise on Local Tissue Oxygenation in 18 - 30 Year Old Sedentary Men.

    Directory of Open Access Journals (Sweden)

    Yuri Kriel

    Full Text Available High intensity interval training (HIIT has been proposed as a time-efficient format of exercise to reduce the chronic disease burden associated with sedentary behaviour. Changes in oxygen utilisation at the local tissue level during an acute session of HIIT could be the primary stimulus for the health benefits associated with this format of exercise. The recovery periods of HIIT effect the physiological responses that occur during the session. It was hypothesised that in sedentary individuals, local and systemic oxygen utilisation would be higher during HIIT interspersed with active recovery periods, when compared to passive recovery periods.Twelve sedentary males (mean ± SD; age 23 ± 3 yr completed three conditions on a cycle ergometer: 1 HIIT with passive recovery periods between four bouts (HIITPASS 2 HIIT with active recovery periods between four bouts (HIITACT 3 HIITACT with four HIIT bouts replaced with passive periods (REC. Deoxygenated haemoglobin (HHb in the vastus lateralis (VL and gastrocnemius (GN muscles and the pre-frontal cortex (FH, oxygen consumption (VO2, power output and heart rate (HR were measured continuously during the three conditions.There was a significant increase in HHb at VL during bouts 2 (p = 0.017, 3 (p = 0.035 and 4 (p = 0.035 in HIITACT, compared to HIITPASS. Mean power output was significantly lower in HIITACT, compared to HIITPASS (p < 0.001. There was a significant main effect for site in both HIITPASS (p = 0.029 and HIITACT (p = 0.005. There were no significant differences in VO2 and HR between HIITPASS and HIITACT.The increase in HHb at VL and the lower mean power output during HIITACT could indicate that a higher level of deoxygenation contributes to decreased mechanical power in sedentary participants. The significant differences in HHb between sites indicates the specificity of oxygen utilisation.

  11. Tissue oxygenation in brain, muscle, and fat in a rat model of sleep apnea: differential effect of obstructive apneas and intermittent hypoxia.

    Science.gov (United States)

    Almendros, Isaac; Farré, Ramon; Planas, Anna M; Torres, Marta; Bonsignore, Maria R; Navajas, Daniel; Montserrat, Josep M

    2011-08-01

    To test the hypotheses that the dynamic changes in brain oxygen partial pressure (PtO(2)) in response to obstructive apneas or to intermittent hypoxia differ from those in other organs and that the changes in brain PtO(2) in response to obstructive apneas is a source of oxidative stress. Prospective controlled animal study. University laboratory. 98 Sprague-Dawley rats. Cerebral cortex, skeletal muscle, or visceral fat tissues were exposed in anesthetized animals subjected to either obstructive apneas or intermittent hypoxia (apneic and hypoxic events of 15 s each and 60 events/h) for 1 h. Arterial oxygen saturation (SpO(2)) presented a stable pattern, with similar desaturations during both stimuli. The PtO(2) was measured by a microelectrode. During obstructive apneas, a fast increase in cerebral PtO(2) was observed (38.2 ± 3.4 vs. 54.8 ± 5.9 mm Hg) but not in the rest of tissues. This particular cerebral response was not found during intermittent hypoxia. The cerebral content of reduced glutathione was decreased after obstructive apneas (46.2% ± 15.2%) compared to controls (100.0% ± 14.7%), but not after intermittent hypoxia. This antioxidant consumption after obstructive apneas was accompanied by increased cerebral lipid peroxidation under this condition. No changes were observed for these markers in the other tissues. These results suggest that cerebral cortex could be protected in some way from hypoxic periods caused by obstructive apneas. The increased cerebral PtO(2) during obstructive apneas may, however, cause harmful effects (oxidative stress). The obstructive apnea model appears to be more adequate than the intermittent hypoxia model for studying brain changes associated with OSA.

  12. Nonthermal Ablation by Using Intravascular Oxygen Radical Generation with WST11: Dynamic Tissue Effects and Implications for Focal Therapy

    Science.gov (United States)

    Kimm, Simon Y.; Tarin, Tatum V.; Monette, Sébastien; Srimathveeravalli, Govindarajan; Gerber, Daniel; Durack, Jeremy C.; Solomon, Stephen B.; Scardino, Peter T.; Scherz, Avigdor

    2016-01-01

    Purpose To examine the hypothesis that vascular-targeted photodynamic therapy (VTP) with WST11 and clinically relevant parameters can be used to ablate target tissues in a non–tumor-bearing large-animal model while selectively sparing blood vessels and collagen. Materials and Methods By using an institutional animal care and use committee–approved protocol, 68 ablations were performed in the kidneys (cortex and medulla) and livers of 27 adult pigs. Posttreatment evaluation was conducted with contrast material–enhanced computed tomography in the live animals at 24 hours. Immunohistochemistry was evaluated and histologic examination with hematoxylin-eosin staining was performed at 4 hours, 24 hours, and 7 days. Intravenous infusion of WST11 (4 mg per kilogram of body weight) was followed by using near-infrared illumination (753 nm for 20 minutes) through optical fibers prepositioned in target tissues by using a fixed template. Treated areas were scanned, measured, and statistically analyzed by using the Student t test and two-way analysis of variance. Results Focal WST11 VTP treatment in the liver and kidney by using a single optical fiber resulted in well-demarcated cylindrical zones of nonthermal necrosis concentrically oriented around the light-emitting diffuser, with no intervening viable parenchymal cells. The radius of ablated tissue increased from approximately 5 mm at 150 mW to approximately 7 mm at 415 mW (P necrosis. Patterns of acute injury within 24 hours were consistent with microcirculatory flow arrest and collagen preservation (demonstrated with trichrome staining). In the peripheral ablation zone, blood vessels at least 40 μm in diameter were selectively preserved and remained functional at 7 days. Ablated tissues exhibited progressive fibrosis and chronic inflammatory cell infiltrates. No histologic changes consistent with thermal injury were observed in blood vessels or collagen. The renal hilum and collecting system did not show treatment

  13. Control and monitoring of oxygen content in molten metals. Application to lead and lead-bismuth melts

    International Nuclear Information System (INIS)

    Ghetta, V.; Fouletier, J.; Henault, M.; Le Moulec, A.

    2002-01-01

    The sources of error in potentiometric measurements of the oxygen activity in molten metals and the methods proposed to reduce these measurements errors are described. Specific constraints related to low temperature measurements are emphasized. Two set-ups for control of the oxygen activity in molten lead and lead-bismuth were developed. They involve zirconia-based cells, i.e., an oxygen pump and an oxygen probe. The performance of the set-ups was characterized attempts to reduce the working temperature (T<450 deg C) are discussed. (authors)

  14. Continuous Nondestructive Monitoring Method Using the Reconstructed Three-Dimensional Conductivity Images via GREIT for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Sujin Ahn

    2014-01-01

    Full Text Available A continuous Nondestructive monitoring method is required to apply proper feedback controls during tissue regeneration. Conductivity is one of valuable information to assess the physiological function and structural formation of regenerated tissues or cultured cells. However, conductivity imaging methods suffered from inherited ill-posed characteristics in image reconstruction, unknown boundary geometry, uncertainty in electrode position, and systematic artifacts. In order to overcome the limitation of microscopic electrical impedance tomography (micro-EIT, we applied a 3D-specific container with a fixed boundary geometry and electrode configuration to maximize the performance of Graz consensus reconstruction algorithm for EIT (GREIT. The separation of driving and sensing electrodes allows us to simplify the hardware complexity and obtain higher measurement accuracy from a large number of small sensing electrodes. We investigated the applicability of the GREIT to 3D micro-EIT images via numerical simulations and large-scale phantom experiments. We could reconstruct multiple objects regardless of the location. The resolution was 5 mm3 with 30 dB SNR and the position error was less than 2.54 mm. This shows that the new micro-EIT system integrated with GREIT is robust with the intended resolution. With further refinement and scaling down to a microscale container, it may be a continuous nondestructive monitoring tool for tissue engineering applications.

  15. Replacement of chemical oxygen demand (COD) with total organic carbon (TOC) for monitoring wastewater treatment performance to minimize disposal of toxic analytical waste.

    Science.gov (United States)

    Dubber, Donata; Gray, Nicholas F

    2010-10-01

    Chemical oxygen demand (COD) is widely used for wastewater monitoring, design, modeling and plant operational analysis. However this method results in the production of hazardous wastes including mercury and hexavalent chromium. The study examined the replacement of COD with total organic carbon (TOC) for general performance monitoring by comparing their relationship with influent and effluent samples from 11 wastewater treatment plants. Biochemical oxygen demand (BOD5) was also included in the comparison as a control. The results show significant linear relationships between TOC, COD and BOD5 in settled (influent) domestic and municipal wastewaters, but only between COD and TOC in treated effluents. The study concludes that TOC can be reliably used for the generic replacement of both COD (COD=49.2+3.00*TOC) and BOD5 (BOD5=23.7+1.68*TOC) in influent wastewaters but only for COD (COD=7.25+2.99*TOC) in final effluents.

  16. Laser Doppler imaging, thermographic imaging, and tissue oxygen saturation measurements detect early skin reactions during breast radiotherapy

    Science.gov (United States)

    Harrison, David K.; Harrison, Eileen M.; Newton, David J.; Windsor, Phyllis M.

    2001-05-01

    A range of acute skin reactions, ranging from mild erythema to moist desquamation, can be seen in patients receiving standard fractionated radiotherapy to the breast for conservation therapy of breast carcinoma. In a number of cases these reactions can cause considerable discomfort and seriously affect the patient's quality of life. In previous studies we have used the techniques of laser Doppler imaging, digital thermographic imaging and lightguide spectrophotometry to study oxygen supply and blood flow in inflammatory reactions induced experimentally in forearm skin. The present study is an attempt to use the same techniques to investigate whether any or all of them can detect changes in breast skin very early on in the course of radiotherapy treatment. A further aim of the longer term study is to investigate to what extent these early changes may be able to predict the occurrence later of severe acute or delayed reactions.

  17. Study and development of a fluorescence based sensor system for monitoring oxygen in wine production : the WOW project

    NARCIS (Netherlands)

    Trivellin, Nicola; Barbisan, Diego; Badocco, Denis; Pastore, Paolo; Meneghesso, Gaudenzio; Meneghini, Matteo; Zanoni, Enrico; Belgioioso, Giuseppe; Cenedese, Angelo

    2018-01-01

    The importance of oxygen in the winemaking process is widely known, as it affects the chemical aspects and therefore the organoleptic characteristics of the final product. Hence, it is evident the usefulness of a continuous and real-time measurements of the levels of oxygen in the various stages of

  18. The oxygen sensitivity of a multipoint antimony electrode for tissue pH measurements. A study of the sensitivity for in vivo PO2 variations below 6 kPa.

    Science.gov (United States)

    Sjöberg, F; Edwall, G; Lund, N

    1987-02-01

    Monocrystalline micro antimony electrodes in a multipoint arrangement as described by Lund et al. were placed on the skeletal muscle surface of the rabbit. Tissue oxygen levels were measured simultaneously with the MDO (Mehrdraht Dortmund Oberfläche) oxygen electrode. The sensitivity for variations in tissue PO2 (PO2(t)) was evaluated for the antimony metal-metal oxide sensor. The sensitivity (delta E/delta log10 PO2)+/- SE was found to be 21.8 +/- 1.2 mV in the interval between 0.1 kPa and 1 kPa and 53 +/- 5 mV in the interval between 1 kPa and 6 kPa. These results are not consistent with the oxygen sensitivity of monocrystalline antimony described in vitro, but are in agreement with the findings of Nilsson & Edwall. A plausible explanation for the S-shaped oxygen sensitivity curve of antimony at oxygen levels below 10 kPa could be an interaction, at the electrode surface, between the dissolved oxygen and the oxygen bound to haemoglobin. If this is the case, the use of an antimony electrode would make possible the determination of the dissociation of oxyhaemoglobin in tissues.

  19. Non-invasive tissue oximetry following unilateral DIEP-flap reconstruction: A pilot evaluation

    Directory of Open Access Journals (Sweden)

    N.P.A. Vranken

    2017-06-01

    Conclusion: Continuous non-invasive tissue oxygen saturation is suitable for postoperative monitoring of DIEP-flaps, and StO2 pattern may aid in early identification of vascular compromise in DIEP-flaps.

  20. Engineered hybrid cardiac patches with multifunctional electronics for online monitoring and regulation of tissue function.

    Science.gov (United States)

    Feiner, Ron; Engel, Leeya; Fleischer, Sharon; Malki, Maayan; Gal, Idan; Shapira, Assaf; Shacham-Diamand, Yosi; Dvir, Tal

    2016-06-01

    In cardiac tissue engineering approaches to treat myocardial infarction, cardiac cells are seeded within three-dimensional porous scaffolds to create functional cardiac patches. However, current cardiac patches do not allow for online monitoring and reporting of engineered-tissue performance, and do not interfere to deliver signals for patch activation or to enable its integration with the host. Here, we report an engineered cardiac patch that integrates cardiac cells with flexible, freestanding electronics and a 3D nanocomposite scaffold. The patch exhibited robust electronic properties, enabling the recording of cellular electrical activities and the on-demand provision of electrical stimulation for synchronizing cell contraction. We also show that electroactive polymers containing biological factors can be deposited on designated electrodes to release drugs in the patch microenvironment on demand. We expect that the integration of complex electronics within cardiac patches will eventually provide therapeutic control and regulation of cardiac function.

  1. Quantitative optical diagnostics in pathology recognition and monitoring of tissue reaction to PDT

    Science.gov (United States)

    Kirillin, Mikhail; Shakhova, Maria; Meller, Alina; Sapunov, Dmitry; Agrba, Pavel; Khilov, Alexander; Pasukhin, Mikhail; Kondratieva, Olga; Chikalova, Ksenia; Motovilova, Tatiana; Sergeeva, Ekaterina; Turchin, Ilya; Shakhova, Natalia

    2017-07-01

    Optical coherence tomography (OCT) is currently actively introduced into clinical practice. Besides diagnostics, it can be efficiently employed for treatment monitoring allowing for timely correction of the treatment procedure. In monitoring of photodynamic therapy (PDT) traditionally employed fluorescence imaging (FI) can benefit from complementary use of OCT. Additional diagnostic efficiency can be derived from numerical processing of optical diagnostics data providing more information compared to visual evaluation. In this paper we report on application of OCT together with numerical processing for clinical diagnostic in gynecology and otolaryngology, for monitoring of PDT in otolaryngology and on OCT and FI applications in clinical and aesthetic dermatology. Image numerical processing and quantification provides increase in diagnostic accuracy. Keywords: optical coherence tomography, fluorescence imaging, photod

  2. Harmonic motion imaging for focused ultrasound (HMIFU): a fully integrated technique for sonication and monitoring of thermal ablation in tissues

    International Nuclear Information System (INIS)

    Maleke, C; Konofagou, E E

    2008-01-01

    FUS (focused ultrasound), or HIFU (high-intensity-focused ultrasound) therapy, a minimally or non-invasive procedure that uses ultrasound to generate thermal necrosis, has been proven successful in several clinical applications. This paper discusses a method for monitoring thermal treatment at different sonication durations (10 s, 20 s and 30 s) using the amplitude-modulated (AM) harmonic motion imaging for focused ultrasound (HMIFU) technique in bovine liver samples in vitro. The feasibility of HMI for characterizing mechanical tissue properties has previously been demonstrated. Here, a confocal transducer, combining a 4.68 MHz therapy (FUS) and a 7.5 MHz diagnostic (pulse-echo) transducer, was used. The therapy transducer was driven by a low-frequency AM continuous signal at 25 Hz, producing a stable harmonic radiation force oscillating at the modulation frequency. A pulser/receiver was used to drive the pulse-echo transducer at a pulse repetition frequency (PRF) of 5.4 kHz. Radio-frequency (RF) signals were acquired using a standard pulse-echo technique. The temperature near the ablation region was simultaneously monitored. Both RF signals and temperature measurements were obtained before, during and after sonication. The resulting axial tissue displacement was estimated using one-dimensional cross correlation. When temperature at the focal zone was above 48 deg. C during heating, the coagulation necrosis occurred and tissue damage was irreversible. The HMI displacement profiles in relation to the temperature and sonication durations were analyzed. At the beginning of heating, the temperature at the focus increased sharply, while the tissue stiffness decreased resulting in higher HMI displacements. This was confirmed by an increase of 0.8 μm deg. C -1 (r = 0.93, p -1 , r = -0.92, p -1 , prior to and after lesion formation in seven bovine liver samples, respectively. This technique was thus capable of following the protein-denatured lesion formation based on the

  3. Monitoring programmed cell death of living plant tissues in microfluidics using electrochemical and optical techniques

    DEFF Research Database (Denmark)

    Mark, Christina; Heiskanen, Arto; Svensson, Birte

    Programmed cell death (PCD) in plants can influence the outcome of yield and quality of crops through its important role in seed germination and the defence process against pathogens. The main scope of the project is to apply microfluidic cell culture for the measurement of electrochemically......, since it is known that reactive oxygen species, which are affected by changes in the redox activity of the cells3, are involved in PCD in plants, but the relationship between and mechanisms behind ROS and PCD is only poorly understood in plant cells4. Recently, it has been shown, using optical detection...

  4. Contact-free monitoring of vessel graft stiffness - proof of concept as a tool for vascular tissue engineering.

    Science.gov (United States)

    Hoenicka, Markus; Kaspar, Marcel; Schmid, Christof; Liebold, Andreas; Schrammel, Siegfried

    2017-10-01

    Tissue-engineered vessel grafts have to mimic the biomechanical properties of native blood vessels. Manufacturing processes often condition grafts to adapt them to the target flow conditions. Graft stiffness is influenced by material properties and dimensions and determines graft compliance. This proof-of-concept study evaluated a contact-free method to monitor biomechanical properties without compromising sterility. Forced vibration response analysis was performed on human umbilical vein (HUV) segments mounted in a buffer-filled tubing system. A linear motor and a dynamic signal analyser were used to excite the fluid by white noise (0-200 Hz). Vein responses were read out by laser triangulation and analysed by fast Fourier transformation. Modal analysis was performed by monitoring multiple positions of the vessel surface. As an inverse model of graft stiffening during conditioning, HUV were digested proteolytically, and the course of natural frequencies (NFs) was monitored over 120 min. Human umbilical vein showed up to five modes with NFs in the range of 5-100 Hz. The first natural frequencies of HUV did not alter over time while incubated in buffer (p = 0.555), whereas both collagenase (-35%, p = 0.0061) and elastase (-45%, p direct measurement of stiffness as an important biomechanical property, obviating the need to monitor surrogate parameters. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  5. 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

  6. 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

  7. 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

  8. What can stable isotope analysis of top predator tissues contribute to monitoring of tundra ecosystems?

    NARCIS (Netherlands)

    Ehrich, D.; Ims, R.A.; Yoccoz, N.G.; Lecomte, N.; Killengreen, S.T.; Fuglei, E.; Rodnikova, A.Y.; Ebbinge, B.S.; Menyushina, I.E.; Nolet, Bart; Prokovsky, I.G.; Popov, I.Y.; Schmidt, N.M.; Sokolov, A.; Sokolova, N.A.; Sokolov, V.A.

    2015-01-01

    Understanding how climate change and increasing human impacts may exert pressure on ecosystems and threaten biodiversity requires efficient monitoring programs. Indicator species have been proposed as useful tools, and predators and their diet may be particularly suitable. The vast and remote arctic

  9. Effect of tissue scaffold topography on protein structure monitored by fluorescence spectroscopy

    NARCIS (Netherlands)

    Portugal, C.A.M.; Truckenmüller, R.K.; Stamatialis, Dimitrios; Crespo, J.G.

    2014-01-01

    The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell–scaffold interactions. The changes induced upon adsorption

  10. Post-operative monitoring of tissue transfers: advantages using contrast enhanced ultrasound (CEUS) and contrast enhanced MRI (ceMRI) with dynamic perfusion analysis?

    Science.gov (United States)

    Lamby, P; Prantl, L; Fellner, C; Geis, S; Jung, E M

    2011-01-01

    The immediate evaluation of microvascular tissue flaps with respect to microcirculation after transplantation is crucial for optimal monitoring and outcome. The purpose of our investigation was to evaluate the clinical value of contrast-enhanced ultrasound (CEUS) and contrast-enhanced MRI (ceMRI) for monitoring the integrity of tissue flaps in plastic surgery. To this end, we investigated 10 patients (47 ± 16 a) between postoperative day 7 and 14 who underwent flap surgery in order to cover tissue defects in various body regions. For CEUS we utilized the GE LOGIQ E9 equipped with a linear transducer (6-9 MHz). After application of 2.4 ml SonoVue, the tissue perfusion was detected in Low MI-Technique (MI present, both technologies provide an optimal assessment of perfusion in cutaneous, subcutaneous and muscle tissue layers, whereby the detection of fatty tissue perfusion is currently more easily detected using CEUS compared to ceMRI.

  11. Espectroscopia no infravermelho próximo para a monitorização da perfusão tecidual Near-infrared spectroscopy for monitoring peripheral tissue perfusion in critically ill patients

    Directory of Open Access Journals (Sweden)

    Alexandre Lima

    2011-09-01

    Full Text Available A espectroscopia no infravermelho próximo (NIRS tem sido principalmente usada na investigação da oxigenação periférica tecidual de forma não invasiva e contínua. O princípio da espectroscopia consiste na aplicação da luz no comprimento de onda do infravermelho-próximo para avaliar, de forma quantitativa e qualitativa, os componentes moleculares relacionadas à oxigenação tecidual. Baseado na relação das concentrações da deoxiemoglobina e da oxiemoglobina no tecido, a NIRS obtém informações para o cálculo da oxigenação tecidual. Embora possa ser aplicada em qualquer órgão, como método não invasivo é principalmente usada para a monitorização da oxigenação muscular periférica. Os parâmetros medidos pela NIRS podem ser calculados diretamente ou através de intervenções fisiológicas para alterar a circulação no local da aferição, sendo as mais usadas a oclusão arterial e a oclusão venosa. Deste modo, pode-se obter informações sobre a saturação do oxigênio muscular periférico e tecidual, bem como do fluxo sanguíneo e consumo de oxigênio local. Seu uso é direcionado principalmente para a monitorização da oxigenação tecidual periférica durante ressuscitação do choque no trauma e em pacientes sépticos, bem como a monitorização dos distúrbios da microcirculação regional. Esta revisão abordará os princípios físicos da espectroscopia no IV-próximo, e das principais aplicações clínicas deste instrumento de monitorização, com ênfase nos estudos que investigaram a utilidade da NIRS na área de terapia intensiva e também no setor de emergência clínica.Near infrared spectroscopy (NIRS is a non-invasive technique that allows determination of tissue oxygenation based on spectro-photometric quantitation of oxy- and deoxyhemoglobin within a tissue. This technique has gained acceptance as a tool to monitor peripheral tissue perfusion in critically ill patient. NIRS principle is based on

  12. Cerebral time domain-NIRS: reproducibility analysis, optical properties, hemoglobin species and tissue oxygen saturation in a cohort of adult subjects.

    Science.gov (United States)

    Giacalone, Giacomo; Zanoletti, Marta; Contini, Davide; Re, Rebecca; Spinelli, Lorenzo; Roveri, Luisa; Torricelli, Alessandro

    2017-11-01

    The reproducibility of cerebral time-domain near-infrared spectroscopy (TD-NIRS) has not been investigated so far. Besides, reference intervals of cerebral optical properties, of absolute concentrations of deoxygenated-hemoglobin (HbR), oxygenated-hemoglobin (HbO), total hemoglobin (HbT) and tissue oxygen saturation (StO 2 ) and their variability have not been reported. We have addressed these issues on a sample of 88 adult healthy subjects. TD-NIRS measurements at 690, 785, 830 nm were fitted with the diffusion model for semi-infinite homogenous media. Reproducibility, performed on 3 measurements at 5 minutes intervals, ranges from 1.8 to 6.9% for each of the hemoglobin species. The mean ± SD global values of HbR, HbO, HbT, StO 2 are respectively 24 ± 7 μM, 33.3 ± 9.5 μM, 57.4 ± 15.8 μM, 58 ± 4.2%. StO 2 displays the narrowest range of variability across brain regions.

  13. Monitoring programmed cell death of living plant tissues in microfluidics using electrochemical and optical techniques

    DEFF Research Database (Denmark)

    Mark, Christina; Zor, Kinga; Heiskanen, Arto

    such as redox activity, O2 and H2O2 concentration, pH, cell viability and release of target enzymes such as α-amylase. We have optimised an intracellular, whole-cell redox activity assay[3] that detects changes in redox activity in barley aleurone layer during PCD. The assay uses a double mediator......This project focuses on developing and applying a tissue culture system with electrochemical and optical detection techniques for tissue culture of barley aleurone layer to increase understanding of the underlying mechanisms of programmed cell death (PCD) in plants. The major advantage......-system to electrochemically measure redox activity via changes in the NADP:NADPH ratio. Experiments show that redox activity changes depend on phytohormone activation or inactivation of aleurone layer metabolism and subsequent PCD. We have also successfully detected PCD induced by phytohormones in barley aleurone layer using...

  14. Continuous glucose monitoring in subcutaneous tissue using factory-calibrated sensors: a pilot study.

    Science.gov (United States)

    Hoss, Udo; Jeddi, Iman; Schulz, Mark; Budiman, Erwin; Bhogal, Claire; McGarraugh, Geoffrey

    2010-08-01

    Commercial continuous subcutaneous glucose monitors require in vivo calibration using capillary blood glucose tests. Feasibility of factory calibration, i.e., sensor batch characterization in vitro with no further need for in vivo calibration, requires a predictable and stable in vivo sensor sensitivity and limited inter- and intra-subject variation of the ratio of interstitial to blood glucose concentration. Twelve volunteers wore two FreeStyle Navigator (Abbott Diabetes Care, Alameda, CA) continuous glucose monitoring systems for 5 days in parallel for two consecutive sensor wears (four sensors per subject, 48 sensors total). Sensors from a prototype sensor lot with a low variability in glucose sensitivity were used for the study. Median sensor sensitivity values based on capillary blood glucose were calculated per sensor and compared for inter- and intra-subject variation. Mean absolute relative difference (MARD) calculation and error grid analysis were performed using a single calibration factor for all sensors to simulate factory calibration and compared to standard fingerstick calibration. Sensor sensitivity variation in vitro was 4.6%, which increased to 8.3% in vivo (P glucose monitoring is feasible with similar accuracy to standard fingerstick calibration. Additional data are required to confirm this result in subjects with diabetes.

  15. Inverse Regulation of Early and Late Chondrogenic Differentiation by Oxygen Tension Provides Cues for Stem Cell-Based Cartilage Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Sophie Portron

    2015-01-01

    Full Text Available Background/Aims: Multipotent stem/stromal cells (MSC are considered promising for cartilage tissue engineering. However, chondrogenic differentiation of MSC can ultimately lead to the formation of hypertrophic chondrocytes responsible for the calcification of cartilage. To prevent the production of this calcified matrix at the articular site, the late hypertrophic differentiation of MSCs must be carefully controlled. Given that articular cartilage is avascular, we hypothesized that in addition to its stimulatory role in the early differentiation of chondrogenic cells, hypoxia may prevent their late hypertrophic conversion. Methods: Early and late chondrogenic differentiation were evaluated using human adipose MSC and murine ATDC5 cells cultured under either normoxic (21%O2 or hypoxic (5%O2 conditions. To investigate the effect of hypoxia on late chondrogenic differentiation, the transcriptional activity of hypoxia-inducible factor-1alpha (HIF-1α and HIF-2α were evaluated using the NoShift DNA-binding assay and through modulation of their activity (chemical inhibitor, RNA interference. Results: Our data demonstrate that low oxygen tension not only stimulates the early chondrogenic commitment of two complementary models of chondrogenic cells, but also inhibits their hypertrophic differentiation. Conclusion: These results suggest that hypoxia can be used as an instrumental tool to prevent the formation of a calcified matrix in MSC-based cartilage tissue engineering.

  16. A Prospective Randomized Study of Brain Tissue Oxygen Pressure-Guided Management in Moderate and Severe Traumatic Brain Injury Patients

    Directory of Open Access Journals (Sweden)

    Chien-Min Lin

    2015-01-01

    Full Text Available The purpose of this study was to compare the effect of PbtO2-guided therapy with traditional intracranial pressure- (ICP- guided treatment on the management of cerebral variables, therapeutic interventions, survival rates, and neurological outcomes of moderate and severe traumatic brain injury (TBI patients. From 2009 to 2010, TBI patients with a Glasgow coma scale 20 mmHg, and 27 patients were treated with ICP-guided therapy (ICP 60 mmHg in the neurosurgical intensive care unit (NICU; demographic characteristics were similar across groups. The survival rate in the PbtO2-guided group was also significantly increased at 3 and 6 months after injury. Moreover, there was a significant correlation between the PbtO2 signal and Glasgow outcome scale-extended in patients from 1 to 6 months after injury. This finding demonstrates that therapy directed by PbtO2 monitoring is valuable for the treatment of patients with moderate and severe TBI and that increasing PaO2 to 150 mmHg may be efficacious for preventing cerebral hypoxic events after brain trauma.

  17. Anesthesia for arthroscopic shoulder surgery in the beach chair position: monitoring of cerebral oxygenation using combined bispectral index and near-infrared spectroscopy.

    Science.gov (United States)

    Kawano, Hiroaki; Matsumoto, Tomomi

    2014-10-01

    Recent research has shown that cerebrovascular complications following shoulder surgery performed in the beach chair position under general anesthesia arise secondary to cerebral ischemia. Appropriate management of cerebral oxygenation is thus one of the primary goals of anesthetic management during such procedures. The present report describes the case of a 65-year-old male patient, in which both bispectral index (BIS) and near-infrared spectroscopy (NIRS) were used to monitor cerebral oxygenation. During the positioning, we observed an increased suppression ratio (SR) while BIS and regional cerebral oxygen saturation (rSO2) were at adequate level. In view of the difference in blood pressure between the heart and the base of the brain, blood pressure was maintained to ensure adequate cerebral perfusion. Although intraoperative rSO2 was at or around the cut-off point (a 12% relative decrease from baseline), no marked decrease in BIS or further increase in the SR was observed. Monitoring of cerebral perfusion using combined BIS and NIRS optimized anesthetic management during the performance of arthroscopic shoulder surgery in the beach chair position.

  18. Effect of tissue scaffold topography on protein structure monitored by fluorescence spectroscopy.

    Science.gov (United States)

    Portugal, Carla A M; Truckenmüller, Roman; Stamatialis, Dimitrios; Crespo, João G

    2014-11-10

    The impact of surface topography on the structure of proteins upon adhesion was assessed through non-invasive fluorescence monitoring. This study aimed at obtaining a better understanding about the role of protein structural status on cell-scaffold interactions. The changes induced upon adsorption of two model proteins with different geometries, trypsin (globular conformation) and fibrinogen (rod-shaped conformation) on poly-l-lactic acid (PLLA) scaffolds with different surface topographies, flat, fibrous and surfaces with aligned nanogrooves, were assessed by fluorescence spectroscopy monitoring, using tryptophan as structural probe. Hence, the maximum emission blue shift and the increase of fluorescence anisotropy observed after adsorption of globular and rod-like shaped proteins on surfaces with parallel nanogrooves were ascribed to more intense protein-surface interactions. Furthermore, the decrease of fluorescence anisotropy observed upon adsorption of proteins to scaffolds with fibrous morphology was more significant for rod-shaped proteins. This effect was associated to the ability of these proteins to adjust to curved surfaces. The additional unfolding of proteins induced upon adsorption on scaffolds with a fibrous morphology may be the reason for better cell attachment there, promoting an easier access of cell receptors to initially hidden protein regions (e.g. RGDS sequence), which are known to have a determinant role in cell attaching processes. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Monitoring of treatment with vitamin K antagonists: recombinant thromboplastins are more sensitive to factor VII than tissue-extract thromboplastins.

    Science.gov (United States)

    Biedermann, J S; van den Besselaar, A M H P; de Maat, M P M; Leebeek, F W G; Kruip, M J H A

    2017-03-01

    regarding FVII sensitivity exist between various thromboplastins used for VKA monitoring. Recombinant human thromboplastins are more sensitive to FVII than tissue-extract thromboplastins. Therefore, thromboplastin choice may affect FVII-mediated INR stability. © 2017 International Society on Thrombosis and Haemostasis.

  20. Tissue Necrosis Monitoring for HIFU Ablation with T1 Contrast MRI Imaging

    Science.gov (United States)

    Hwang, San-Chao; Yao, Ching; Kuo, Ih-Yuan; Tsai, Wei-Cheng; Chang, Hsu

    2011-09-01

    In MR-guided HIFU ablation, MTC (Magnetization Transfer Contrast) or perfusion imaging is usually used after ablation to evaluate the ablated area based on the thermally induced necrosis contrast. In our MR-guided HIFU ablation study, a T1 contrast MRI scan sequence has been used to distinguish between necrotic and non-necrotic tissue. The ablation of porcine meat in-vitro and in-vivo pig leg muscle show that the necrotic area of T1 contrast MRI image coincides with the photographs of sliced specimen. The sequence is considerably easier to apply than MTC or perfusion imaging, while giving good necrosis contrast. In addition, no injection of contrast agent is needed, allowing multiple scans to be applied throughout the entire ablation procedure.

  1. In vivo cryoablation of prostate tissue with temperature monitoring by optoacoustic imaging

    Science.gov (United States)

    Petrova, Elena V.; Motamedi, Massoud; Oraevsky, Alexander A.; Ermilov, Sergey A.

    2016-03-01

    Cryoablation of prostate cancer is an FDA approved clinical procedure, which involves repetitive rapid cooling of a lesion to lethal temperatures of -40°C and below. The major drawback of the technique is the insufficient control over the fast thermal processes that may result in severe complications (impotence, incontinence, perforation of the rectal wall) and morbidity. The developed optoacoustic imaging technique provides non-invasive real-time temperature mapping of tissue adjacent to prostate and enables more efficient control over the procedure, which is necessary to reduce side effects and accelerate the physician's learning curve. In these studies we successfully demonstrated real-time transrectal optoacoustic imaging during prostate cryoablation in live canine model focused on optoacoustic thermography of the rectal wall within the depth of 1cm. Our method utilized previously discovered universal thermal dependence of the normalized optoacoustic response of blood. Nanosecond-pulse radiation of Ti-Sapphire laser tuned to the isosbestic point of hemoglobin (802+/-3 nm) was delivered via fiberoptic illuminators assembled on both sides of the linear array of the 128-channel transrectal ultrasound probe. Temperature readouts at discrete locations inside and nearby prostate were also performed using standard transperineal needle sensors. The effect of homeostasis on optoacoustic imaging in live tissue was examined during cooling and shown to be significant only within the range of +/-1.5°C in respect to the body temperature. Accuracy of in vivo optoacoustic temperature measurements was determined as +/-2°C for the range of temperature from +35 to -15°C, which is more than sufficient for tracking the essential isotherms in the course of clinical procedures.

  2. Real-time monitoring of luminescent lifetime changes of PtOEP oxygen sensing film with LED/photodiode-based time-domain lifetime device.

    Science.gov (United States)

    Ji, Shaomin; Wu, Wanhua; Wu, Yubo; Zhao, Taiyang; Zhou, Fuke; Yang, Yubin; Zhang, Xin; Liang, Xiaofen; Wu, Wenting; Chi, Lina; Wang, Zhonggang; Zhao, Jianzhang

    2009-05-01

    A cost-effective LED/photodiode(PD)-based time-domain luminescent lifetime measuring device with rugged electronics and simplified algorithms was assembled and successfully used to characterize oxygen sensing films, by continuously monitoring phosphorescence lifetime changes of phosphorescent platinum octaethylporphyrin (PtOEP) in cardo poly(aryl ether ketone) polymer (IMPEK-C) vs. variation of the oxygen partial pressure in a gas mixture (O(2)/N(2)). The results determined by both phosphorescence lifetime and intensity monitoring were compared and the lifetime mode gave results which are in good agreement with the intensity mode. The lifetime-based linear Stern-Volmer plot indicates that the PtOEP molecules are nearly homogeneously distributed in the sensing film. The phosphorescent lifetime of the PtOEP film changes from 75 micros in neat N(2) to less than 2 micros in neat O(2). The sensing system (by combination of the PtOEP sensing film with the home-assembled lifetime device) gives a high lifetime-based O(2) sensing resolution, e.g. about 2 micros Torr(-1) for low O(2) concentration (below 3.5% O(2), V/V). This feasible lifetime device configuration is affordable to most sensor laboratories and the device may facilitate the study of O(2) sensing material with the continuous lifetime monitoring method.

  3. Non-randomised phase II trial of hyperbaric oxygen therapy in patients with chronic arm lymphoedema and tissue fibrosis after radiotherapy for early breast cancer

    International Nuclear Information System (INIS)

    Gothard, Lone; Stanton, Anthony; MacLaren, Julie; Lawrence, David; Hall, Emma; Mortimer, Peter; Parkin, Eileen; Pritchard, Joyce; Risdall, Jane; Sawyer, Robert; Woods, Mary; Yarnold, John

    2004-01-01

    Background: Radiation-induced arm lymphoedema is a common and distressing complication of curative treatment for early breast cancer. Hyperbaric oxygen (HBO 2 ) therapy promotes healing in bone rendered ischaemic by radiotherapy, and may help some soft-tissue injuries too, but is untested in arm lymphoedema. Methods: Twenty-one eligible research volunteers with a minimum 30% increase in arm volume in the years after axillary/supraclavicular radiotherapy (axillary surgery in 18/21 cases) were treated with HBO 2 . The volunteers breathed 100% oxygen at 2.4 ATA for 100 min in a multiplace hyperbaric chamber on 30 occasions over a period of 6 weeks. The volume of the ipsilateral limb, measured opto-electronically by a perometer and expressed as a percentage of contralateral limb volume, was selected as the primary endpoint. A secondary endpoint was local lymph drainage expressed as fractional removal rate of radioisotopic tracer, measured using lymphoscintigraphy. Results: Three out of 19 evaluable patients experienced >20% reduction in arm volume at 12 months. Six out of 13 evaluable patients experienced a >25% improvement in 99 Tc-nanocolloid clearance rate from the ipsilateral forearm measured by quantitative lymphoscintigraphy at 12 months. Overall, there was a statistically significant, but clinically modest, reduction in ipsilateral arm volume at 12 months follow-up compared with baseline (P=0.005). The mean percentage reduction in arm volume from baseline at 12 months was 7.51. Moderate or marked lessening of induration in the irradiated breast, pectoral fold and/or supraclavicular fossa was recorded clinically in 8/15 evaluable patients. Twelve out of 19 evaluable patients volunteered that their arms felt softer, and six reported improvements in shoulder mobility at 12 months. No significant improvements were noted in patient self-assessments of quality of life. Conclusion: Interpretation is limited by the absence of a control group. However, measurement of

  4. Biota monitoring under the Water Framework Directive: On tissue choice and fish species selection.

    Science.gov (United States)

    Fliedner, Annette; Rüdel, Heinz; Lohmann, Nina; Buchmeier, Georgia; Koschorreck, Jan

    2018-04-01

    The study addresses the topic of suitable matrices for chemical analysis in fish monitoring and discusses the effects of data normalization in the context of the European Water Framework Directive (WFD). Differences between species are considered by comparing three frequently monitored species of different trophic levels, i.e., chub (Squalius cephalus, n = 28), (bream, Abramis brama, n = 11), and perch (Perca fluviatilis, n = 19) sampled in the German Danube. The WFD priority substances dioxins, furans and dioxin-like polychlorinated biphenyls (PCDD/F + dl-PCB), polybrominated diphenyl ethers (PBDE), α-hexabromocyclododecane (α-HBCDD), hexachlorobenzene (HCB), mercury (Hg), and perfluorooctane sulfonic acid (PFOS) as well as non-dioxin-like (ndl)-PCB were analyzed separately in fillet and carcass and whole body concentrations were calculated. Hg was analyzed in individual fish fillets and carcasses, all other substances were determined in pool samples, which were compiled on the basis of fish size (3 chub pools, 1 bream pool, 2 perch pools). The data were normalized to 5% lipid weight (or 26% dry mass in the case of Hg and PFOS) for comparison between matrices and species. Hg concentrations were generally higher in fillet than in whole fish (mean whole fish-to-fillet ratio: 0.7) whereas all other substances were mostly higher in whole fish. In the case of lipophilic substances these differences leveled after lipid normalization. Significant correlations (p ≤ .05) were detected between Hg and fish weight and age. Hg concentrations varied least among younger fish. PCDD/F, dl-PCB, ndl-PCB, PBDE, α-HBCDD and HCB correlated significantly (p ≤ .05) with lipid concentrations. Fillet-to-whole fish conversion equations and/or conversion factors were derived for all substances except α-HCBDD. Although more data also for individual fish would be desirable the results are nevertheless a step on the way to translate fillet concentrations of priority

  5. Development of a quantitative PCR assay for monitoring Streptococcus agalactiae colonization and tissue tropism in experimentally infected tilapia.

    Science.gov (United States)

    Su, Y-L; Feng, J; Li, Y-W; Bai, J-S; Li, A-X

    2016-02-01

    Streptococcus agalactiae has become one of the most important emerging pathogens in the aquaculture industry and has resulted in large economic losses for tilapia farms in China. In this study, three pairs of specific primers were designed and tested for their specificities and sensitivities in quantitative real-time polymerase chain reactions (qPCRs) after optimization of the annealing temperature. The primer pair IGS-s/IGS-a, which targets the 16S-23S rRNA intergenic spacer region, was finally chosen, having a detection limit of 8.6 copies of S. agalactiae DNA in a 20 μL reaction mixture. Bacterial tissue tropism was demonstrated by qPCR in Oreochromis niloticus 5 days post-injection with a virulent S. agalactiae strain. Bacterial loads were detected at the highest level in brain, followed by moderately high levels in kidney, heart, spleen, intestines, and eye. Significantly lower bacterial loads were observed in muscle, gill and liver. In addition, significantly lower bacterial loads were observed in the brain of convalescent O. niloticus 14 days post-injection with several different S. agalactiae strains. The qPCR for the detection of S. agalactiae developed in this study provides a quantitative tool for investigating bacterial tissue tropism in infected fish, as well as for monitoring bacterial colonization in convalescent fish. © 2015 John Wiley & Sons Ltd.

  6. Heart tissue of harlequin (hq)/Big Blue mice has elevated reactive oxygen species without significant impact on the frequency and nature of point mutations in nuclear DNA

    Energy Technology Data Exchange (ETDEWEB)

    Crabbe, Rory A. [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada); Hill, Kathleen A., E-mail: khill22@uwo.ca [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada)

    2010-09-10

    Age is a major risk factor for heart disease, and cardiac aging is characterized by elevated mitochondrial reactive oxygen species (ROS) with compromised mitochondrial and nuclear DNA integrity. To assess links between increased ROS levels and mutations, we examined in situ levels of ROS and cII mutation frequency, pattern and spectrum in the heart of harlequin (hq)/Big Blue mice. The hq mouse is a model of premature aging with mitochondrial dysfunction and increased risk of oxidative stress-induced heart disease with the means for in vivo mutation detection. The hq mutation produces a significant downregulation in the X-linked apoptosis-inducing factor gene (Aif) impairing both the antioxidant and oxidative phosphorylation functions of AIF. Brain and skin of hq disease mice have elevated frequencies of point mutations in nuclear DNA and histopathology characterized by cell loss. Reports of associated elevations in ROS in brain and skin have mixed results. Herein, heart in situ ROS levels were elevated in hq disease compared to AIF-proficient mice (p < 0.0001) yet, mutation frequency and pattern were similar in hq disease, hq carrier and AIF-proficient mice. Heart cII mutations were also assessed 15 days following an acute exposure to an exogenous ROS inducer (10 mg paraquat/kg). Acute paraquat exposure with a short mutant manifestation period was insufficient to elevate mutation frequency or alter mutation pattern in the post-mitotic heart tissue of AIF-proficient mice. Paraquat induction of ROS requires mitochondrial complex I and thus is likely compromised in hq mice. Results of this preliminary survey and the context of recent literature suggest that determining causal links between AIF deficiency and the premature aging phenotypes of specific tissues is better addressed with assay of mitochondrial ROS and large-scale changes in mitochondrial DNA in specific cell types.

  7. Heart tissue of harlequin (hq)/Big Blue mice has elevated reactive oxygen species without significant impact on the frequency and nature of point mutations in nuclear DNA

    International Nuclear Information System (INIS)

    Crabbe, Rory A.; Hill, Kathleen A.

    2010-01-01

    Age is a major risk factor for heart disease, and cardiac aging is characterized by elevated mitochondrial reactive oxygen species (ROS) with compromised mitochondrial and nuclear DNA integrity. To assess links between increased ROS levels and mutations, we examined in situ levels of ROS and cII mutation frequency, pattern and spectrum in the heart of harlequin (hq)/Big Blue mice. The hq mouse is a model of premature aging with mitochondrial dysfunction and increased risk of oxidative stress-induced heart disease with the means for in vivo mutation detection. The hq mutation produces a significant downregulation in the X-linked apoptosis-inducing factor gene (Aif) impairing both the antioxidant and oxidative phosphorylation functions of AIF. Brain and skin of hq disease mice have elevated frequencies of point mutations in nuclear DNA and histopathology characterized by cell loss. Reports of associated elevations in ROS in brain and skin have mixed results. Herein, heart in situ ROS levels were elevated in hq disease compared to AIF-proficient mice (p < 0.0001) yet, mutation frequency and pattern were similar in hq disease, hq carrier and AIF-proficient mice. Heart cII mutations were also assessed 15 days following an acute exposure to an exogenous ROS inducer (10 mg paraquat/kg). Acute paraquat exposure with a short mutant manifestation period was insufficient to elevate mutation frequency or alter mutation pattern in the post-mitotic heart tissue of AIF-proficient mice. Paraquat induction of ROS requires mitochondrial complex I and thus is likely compromised in hq mice. Results of this preliminary survey and the context of recent literature suggest that determining causal links between AIF deficiency and the premature aging phenotypes of specific tissues is better addressed with assay of mitochondrial ROS and large-scale changes in mitochondrial DNA in specific cell types.

  8. Support Vector Machine Based Monitoring of Cardio-Cerebrovascular Reserve during Simulated Hemorrhage

    NARCIS (Netherlands)

    van der Ster, Björn J. P.; Bennis, Frank C.; Delhaas, Tammo; Westerhof, Berend E.; Stok, Wim J.; van Lieshout, Johannes J.

    2018-01-01

    Introduction: In the initial phase of hypovolemic shock, mean blood pressure (BP) is maintained by sympathetically mediated vasoconstriction rendering BP monitoring insensitive to detect blood loss early. Late detection can result in reduced tissue oxygenation and eventually cellular death. We

  9. Effects of reactive oxygen species on metabolism monitored by longitudinal 1H single voxel MRS follow-up in patients with mitochondrial disease or cerebral tumors

    International Nuclear Information System (INIS)

    Constans, J M; Collet, S; Hossu, G; Courtheoux, P; Guillamo, J S; Lechapt-Zalcman, E; Valable, S; Lacombe, S; Houee Levin, C; Gauduel, Y A; Dou, W; Ruan, S; Barre, L; Rioult, F; Derlon, J M; Chapon, F; Fong, V; Kauffmann, F

    2011-01-01

    Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metabolism, mitochondrial function, lipid metabolism, necrosis and apoptosis, cell proliferation, and infiltration. These changes could be monitored longitudinally (every 4 months over 6 years) in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI) and spectroscopy (MRS) and MR perfusion. Some examples of early clinical data from longitudinal follow-up monitoring in humans of energy and glycolytic metabolism, lipid metabolism, necrosis, proliferation, and infiltration measured by conventional MRI, MRS and perfusion, and positron emission tomography (PET) are shown in glial brain tumors after therapy. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and therapeutic response.

  10. Effects of reactive oxygen species on metabolism monitored by longitudinal {sup 1}H single voxel MRS follow-up in patients with mitochondrial disease or cerebral tumors

    Energy Technology Data Exchange (ETDEWEB)

    Constans, J M; Collet, S; Hossu, G; Courtheoux, P [MRI Unit, Caen University Hospital, Caen, Normandy (France); Guillamo, J S; Lechapt-Zalcman, E; Valable, S [CERVOxy Group, CI-NAPS, UMR 6232 CI-NAPS, Cyceron, Caen, Normandy (France); Lacombe, S; Houee Levin, C [Paris-Sud 11 University-CNRS, Orsay (France); Gauduel, Y A [LOA, Ecole Polytechnique - ENSTA ParisTech, Palaiseau (France); Dou, W [Tsinghua University, Beijing (China); Ruan, S [CReSTIC EA 3804, IUT Troyes, Troyes (France); Barre, L [GDMTEP, Group CI-NAPS, UMR 6232 CI-NAPS, Cyceron, Caen (France); Rioult, F [CNRS UMR 6072, GREYC, Caen, Normandy (France); Derlon, J M [Neurosurgery and Neurology, Caen University Hospital, Caen, Normandy (France); Chapon, F [Pathology, Caen University Hospital, Caen, Normandy (France); Fong, V [Caen University (France); Kauffmann, F, E-mail: constans-jm@chu-caen.fr [Mathematics LMNO CNRS UMR 6139, Caen University, Caen, Normandy (France)

    2011-01-01

    Free radicals, or Reactive Oxygen Species (ROS), have an effect on energy and glycolytic metabolism, mitochondrial function, lipid metabolism, necrosis and apoptosis, cell proliferation, and infiltration. These changes could be monitored longitudinally (every 4 months over 6 years) in humans with glial brain tumors (low and high grade) after therapy, using conventional magnetic resonance imaging (MRI) and spectroscopy (MRS) and MR perfusion. Some examples of early clinical data from longitudinal follow-up monitoring in humans of energy and glycolytic metabolism, lipid metabolism, necrosis, proliferation, and infiltration measured by conventional MRI, MRS and perfusion, and positron emission tomography (PET) are shown in glial brain tumors after therapy. Despite the difficulty, the variability and unknown factors, these repeated measurements give us a better insight into the nature of the different processes, tumor progression and therapeutic response.

  11. Feasibility of a novel deformable image registration technique to facilitate classification, targeting, and monitoring of tumor and normal tissue

    International Nuclear Information System (INIS)

    Brock, Kristy K.; Dawson, Laura A.; Sharpe, Michael B.; Moseley, Douglas J.; Jaffray, David A.

    2006-01-01

    Purpose: To investigate the feasibility of a biomechanical-based deformable image registration technique for the integration of multimodality imaging, image guided treatment, and response monitoring. Methods and Materials: A multiorgan deformable image registration technique based on finite element modeling (FEM) and surface projection alignment of selected regions of interest with biomechanical material and interface models has been developed. FEM also provides an inherent method for direct tracking specified regions through treatment and follow-up. Results: The technique was demonstrated on 5 liver cancer patients. Differences of up to 1 cm of motion were seen between the diaphragm and the tumor center of mass after deformable image registration of exhale and inhale CT scans. Spatial differences of 5 mm or more were observed for up to 86% of the surface of the defined tumor after deformable image registration of the computed tomography (CT) and magnetic resonance images. Up to 6.8 mm of motion was observed for the tumor after deformable image registration of the CT and cone-beam CT scan after rigid registration of the liver. Deformable registration of the CT to the follow-up CT allowed a more accurate assessment of tumor response. Conclusions: This biomechanical-based deformable image registration technique incorporates classification, targeting, and monitoring of tumor and normal tissue using one methodology

  12. Near Infrared Spectroscopy as a Hemodynamic Monitor in Critical Illness.

    Science.gov (United States)

    Ghanayem, Nancy S; Hoffman, George M

    2016-08-01

    The objectives of this review are to discuss the technology and clinical interpretation of near infrared spectroscopy oximetry and its clinical application in patients with congenital heart disease. MEDLINE and PubMed. Near infrared spectroscopy provides a continuous noninvasive assessment of tissue oxygenation. Over 20 years ago, near infrared spectroscopy was introduced into clinical practice for monitoring cerebral oxygenation during cardiopulmonary bypass in adults. Since that time, the utilization of near infrared spectroscopy has extended into the realm of pediatric cardiac surgery and is increasingly being used in the cardiac ICU to monitor tissue oxygenation perioperatively.

  13. Numerical 3D modeling of heat transfer in human tissues for microwave radiometry monitoring of brown fat metabolism.

    Science.gov (United States)

    Rodrigues, Dario B; Maccarini, Paolo F; Salahi, Sara; Colebeck, Erin; Topsakal, Erdem; Pereira, Pedro J S; Limão-Vieira, Paulo; Stauffer, Paul R

    2013-02-26

    Brown adipose tissue (BAT) plays an important role in whole body metabolism and could potentially mediate weight gain and insulin sensitivity. Although some imaging techniques allow BAT detection, there are currently no viable methods for continuous acquisition of BAT energy expenditure. We present a non-invasive technique for long term monitoring of BAT metabolism using microwave radiometry. A multilayer 3D computational model was created in HFSS™ with 1.5 mm skin, 3-10 mm subcutaneous fat, 200 mm muscle and a BAT region (2-6 cm 3 ) located between fat and muscle. Based on this model, a log-spiral antenna was designed and optimized to maximize reception of thermal emissions from the target (BAT). The power absorption patterns calculated in HFSS™ were combined with simulated thermal distributions computed in COMSOL® to predict radiometric signal measured from an ultra-low-noise microwave radiometer. The power received by the antenna was characterized as a function of different levels of BAT metabolism under cold and noradrenergic stimulation. The optimized frequency band was 1.5-2.2 GHz, with averaged antenna efficiency of 19%. The simulated power received by the radiometric antenna increased 2-9 mdBm (noradrenergic stimulus) and 4-15 mdBm (cold stimulus) corresponding to increased 15-fold BAT metabolism. Results demonstrated the ability to detect thermal radiation from small volumes (2-6 cm 3 ) of BAT located up to 12 mm deep and to monitor small changes (0.5 °C) in BAT metabolism. As such, the developed miniature radiometric antenna sensor appears suitable for non-invasive long term monitoring of BAT metabolism.

  14. [Values of mixed venous oxygen saturation and difference of mixed venous-arterial partial pressure of carbon dioxide in monitoring of oxygen metabolism and treatment after open-heart operation].

    Science.gov (United States)

    Pan, Chuanliang; Zhang, Haiying; Liu, Jianping

    2014-10-01

    To explore the clinic values of early goal directed treatment (EGDT) with the target of mixed venous oxygen saturation (SvO₂) and difference of mixed venous-arterial partial pressure of carbon dioxide (Pv-aCO₂) in monitoring of oxygen metabolism and treatment for patients post open-heart operation. A prospective study was conducted. The adult patients admitted to Third People's Hospital of Chengdu from December 2011 to March 2014 with SvO₂2 mmol/L when admitted in intensive care unit (ICU) were selected on whom elective open-heart operation and pulmonary artery catheter examination were done. All patients received EGDT with the target of SvO₂≥0.65 and Pv-aCO₂<6 mmHg (1 mmHg=0.133 kPa) and were divided into three groups by the values of SvO₂and Pv-aCO₂at 6-hour after ICU admission: A group with SvO₂≥0.65 and Pv-aCO₂<6 mmHg, B group with SvO₂≥0.65 and Pv-aCO₂≥6 mmHg, and C group with SvO₂<0.65. Then the changes and prognosis of the patients in different groups were observed. 103 cases were included, 44 in A group, 31 in B group and 28 in C group. The acute physiology and chronic health evaluation II (APACHEII) score in group A were significantly lower than that in group B or C at 6, 24, 48 and 72 hours (T6, T24, T48, T72) of ICU admission (T6: 11.4 ± 5.8 vs. 13.9 ± 5.4, 13.7 ± 6.4; T24: 8.8 ± 3.7 vs. 10.8 ± 4.8, 11.8 ± 5.4; T48: 8.7 ± 4.1 vs. 9.6 ± 4.2, 10.2 ± 5.1; T72: 7.5 ± 3.4 vs. 8.6 ± 2.9, 9.2 ± 4.2, all P<0.05), and the sequential organ failure assessment (SOFA) showed the same tendency (T6: 6.5 ± 4.3 vs. 8.0 ± 3.8, 9.1 ± 4.5; T24: 6.6 ±3.6 vs. 8.6 ± 3.9, 8.5 ± 3.3; T48: 5.2 ± 3.4 vs. 7.0 ± 3.6, 7.6 ± 5.1; T72: 4.6 ± 2.4 vs. 5.8 ± 2.5, 6.8 ± 3.5, all P<0.05). The values of blood lactic acid (mmol/L) in group A and B were significant lower than that in group C at T6, T24, T48 and T72 (T6: 1.60 ± 0.95, 2.20 ± 1.02 vs. 2.55 ± 1.39; T24: 2.26 ± 1.26, 2.70 ± 1.36 vs. 3.34 ± 2.36; T48: 2.01 ± 1.15, 2.17

  15. Tissue oxygen partial pressure in the tibialis anterior muscle in patients with claudication before, during and after a two-stage treadmill stress test.

    Science.gov (United States)

    Jung, F; Krüger, A; Pindur, G; Sternitzky, R; Franke, R P; Gori, T

    2014-01-01

    The role of the microcirculation in the pathophysiology and symptoms of peripheral arterial obliterative disease (PAOD) has been progressively emphasized during the past decades. Under resting conditions, already, the tissue oxygen partial pressure in the m. tibialis anterior (pO2im) is reduced to about 50% compared to healthy subjects. In the framework of this study the pO2im of patients with PAOD stage II according to Fontaine (n=16) in the m. tibialis anterior was measured under resting conditions and during walking on a treadmill in comparison to healthy subjects (n=10). Under resting conditions the pO2im only marginally differed between PAOD patients and healthy subjects. But during exercise the pO2im dropped significantly more severely in PAOD patients and a return to baseline values could only be reached when the treadmill was stopped and the patients stood still. The pO2im minima correlated clearly with the clinical symptom of calf pain. The data revealed that the pO2im values were lower in PAOD patients and dropped significantly faster during walking compared to the pO2im values in healthy subjects. The pO2im decrease correlated with the calf pain occurring when the pO2im values approached or fell below 10 mmHg.

  16. Combination of On-line pH and Oxygen Transfer Rate Measurement in Shake Flasks by Fiber Optical Technique and Respiration Activity MOnitoring System (RAMOS

    Directory of Open Access Journals (Sweden)

    Jochen Büchs

    2007-12-01

    Full Text Available Shake flasks are commonly used for process development in biotechnologyindustry. For this purpose a lot of information is required from the growth conditions duringthe fermentation experiments. Therefore, Anderlei et al. developed the RAMOS technology[1, 2], which proviedes on-line oxygen and carbondioxide transfer rates in shake flasks.Besides oxygen consumption, the pH in the medium also plays an important role for thesuccessful cultivation of micro-organisms and for process development. For online pHmeasurement fiber optical methods based on fluorophores are available. Here a combinationof the on-line Oxygen Transfer Rate (OTR measurements in the RAMOS device with anon-line, fiber optical pH measurement is presented. To demonstrate the application of thecombined measurement techniques, Escherichia coli cultivations were performed and on-line pH measurements were compared with off-line samples. The combination of on-lineOTR and pH measurements gives a lot of information about the cultivation and, therefore, itis a powerful technique for monitoring shake flask experiments as well as for processdevelopment.

  17. Oxygen Transport to Human Tissues.

    Science.gov (United States)

    1981-06-01

    troops as they crossed the Hindu Kush over the Khawak Pass (11,600 ft), but whether from cold or hunger or altitude is unclear. The name Hindu Kush...pulmonary hypertension and polycythemia and it often relieves symptoms and improves neuropsychological function and the quality of life. Furthermore

  18. Calcification rate and the stable carbon, oxygen, and nitrogen isotopes in the skeleton, host tissue, and zooxanthellae of bleached and recovering Hawaiian corals

    Science.gov (United States)

    Rodrigues, Lisa J.; Grottoli, Andréa G.

    2006-06-01

    We tested the effectiveness of stable isotopes as recorders of physiological changes that occur during coral bleaching and recovery. Montipora capitata and Porites compressa fragments were bleached in outdoor tanks with seawater temperature raised to 30 °C (treatment corals) for one month. Additional fragments were maintained at 27 °C in separate tanks (control corals). After one month, (0 months recovery), buoyant weight was measured and a subset of fragments was frozen. Remaining fragments were returned to the reef for recovery. After 1.5, 4, and 8 months, fragments were collected, measured for buoyant weight, and frozen. Fragments were analyzed for stable carbon and oxygen isotopic compositions of the skeleton (δ 13C s; δ 18O s) and nitrogen and carbon isotopic compositions of the host tissue (δ 15N h; δ 13C h) and zooxanthellae (δ 15N z; δ 13C z). δ 13C s decreased immediately after bleaching in M. capitata, but not in P. compressa. δ 18O s of both species failed to record the warming event. During the remaining months of recovery, δ 13C s and δ 18O s were more enriched in treatment than control corals due to decreases in calcification and metabolic fractionation during that time. Increased δ 15N h of treatment P. compressa may be due to expelled zooxanthellae during bleaching and recovery. Increased δ 15N z at 1.5 months in treatment fragments of both species reflects the increased incorporation of dissolved inorganic nitrogen to facilitate mitotic cell division and/or chl a/cell recovery. Changes in δ 13C h and δ 13C z at 1.5 months in treatment M. capitata indicated a large increase in heterotrophically acquired carbon relative to photosynthetically fixed carbon. We experimentally show that isotopes in coral skeleton, host tissue and zooxanthellae can be used to verify physiological changes during bleaching and recovery, but their use as a proxy for past bleaching events in the skeletal record is limited.

  19. Radiotherapy plus cis-retinoic acid/interferon-α in cervical cancers: response and impact of cRA/IFN on tumor tissue oxygenation

    International Nuclear Information System (INIS)

    Haensgen, Gabriele; Koehler, Uwe; Dunst, Juergen

    1997-01-01

    Background: We have evaluated the impact of 13-cis-retinoic acid plus interferon in combination with radiotherapy on response and on tumor oxygenation in a phase II-study. Materials and methods: From June 1995 through April 1996, thirty-four patients with squamous cell carcinoma FIGO IIB (N=8) and IIIB (N=26) of the cervix who were scheduled for definitive radiotherapy with curative intent received additional treatment with 13-cis-retinoic acid (cRA, isotretinoin) plus interferon-α-2a (IFN-α-2a) as part of a phase-II-protocol at the Universities of Halle-Wittenberg (N=25), Leipzig (N=7) and Dresden (N=2). cRA/IFN-α-2a started 14 days prior to radiotherapy (1 mg per kilogramm body weight cRA orally daily plus 6x10 6 I.U. IFN-α-2a subcutaneously daily). After this induction period, standard radiotherapy was administered (external irradiation with 45Gy in 25 fractions of 1.8Gy plus HDR-brachytherapy with 5x7Gy). During radiotherapy, cRA/IFN-α-2a-treatment was continued with 50% of the daily doses. In 14 patients treated at the University of Halle-Wittenberg, tumor tissue pO 2 -measurements were performed prior to radiotherapy, at 20Gy, and at the end of radiotherapy with an Eppendorf-pO 2 -histograph. The oxygenation data of these patients were compared to 14 patients who had also pO 2 -measurements but had refused to participate in the cRA/IFN-α-2a-protocol and received radiotherapy alone during the same period. Results: All 8 patients with FIGO IIB tumors had a complete clinical remission 3 months after radiotherapy. In FIGO IIIB cancers, (19(26)) (73%) achieved a cCR, 5 (19%) had a PR and 2 died within six months after treatment due to intercurrent disease. The toxicity of cRA/IFN-α-2a was only mild to moderate (fever 43%, skin toxicity 36%, diarrhea 20%, elevation of liver enzymes 20%) with no grade (3(4)) toxicity. The 14 patients with cRA/IFN-α-2a-pretreatment prior to radiotherapy had significant higher median pO 2 -values in their tumors at the

  20. Oxygen-enhanced MRI for patients with connective tissue diseases: Comparison with thin-section CT of capability for pulmonary functional and disease severity assessment

    Energy Technology Data Exchange (ETDEWEB)

    Ohno, Yoshiharu, E-mail: yosirad@kobe-u.ac.jp [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Nishio, Mizuho [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Koyama, Hisanobu [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Yoshikawa, Takeshi; Matsumoto, Sumiaki [Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Seki, Shinichiro [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Tsubakimoto, Maho [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan); Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nakagami-Gun, Okinawa (Japan); Sugimura, Kazuro [Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo (Japan)

    2014-02-15

    Purpose: To prospectively and directly compare oxygen-enhanced (O{sub 2}-enhanced) MRI with thin-section CT for pulmonary functional loss and disease severity assessment in connective tissue disease (CTD) patients with interstitial lung disease (ILD). Materials and methods: Thin-section CT, O{sub 2}-enhanced MRI, pulmonary function test and serum KL-6 were administered to 36 CTD patients with ILD (23 men, 13 women; mean age: 63.9 years) and nine CTD patients without ILD (six men, and three women; mean age: 62.0 years). A relative-enhancement ratio (RER) map was generated from O{sub 2}-enhanced MRI and mean relative enhancement ratio (MRER) for each subject was calculated from all ROI measurements. CT-assessed disease severity was evaluated with a visual scoring system from each of the thin-section CT data. MRER and CT-assessed disease severities of CTD patients with and without ILD were then statistically compared. To assess capability for pulmonary functional loss and disease severity assessment in CTD patients, correlations of MRER and CT-assessed disease severity with pulmonary functional parameters and serum KL-6 in all subjects were statistically determined. Results: MRER and CT-assessed disease severity showed significant differences between CTD patients with (MRER: 0.15 ± 0.08, CT-assessed disease severity: 13.0 ± 7.4%) and without ILD (MRER: 0.25 ± 0.06, p = 0.0011; CT-assessed disease severity: 1.6 ± 1.6%, p < 0.0001). MRER and CT-assessed disease severity correlated significantly with pulmonary functional parameters and serum KL-6 in all subjects (0.61 ≤ r ≤ 0.79, p < 0.05). Conclusion: O{sub 2}-enhanced MRI was found to be as useful as thin-section CT for pulmonary functional loss and disease severity assessment of CTD patients with ILD.

  1. Oxygen-enhanced MRI for patients with connective tissue diseases: Comparison with thin-section CT of capability for pulmonary functional and disease severity assessment

    International Nuclear Information System (INIS)

    Ohno, Yoshiharu; Nishio, Mizuho; Koyama, Hisanobu; Yoshikawa, Takeshi; Matsumoto, Sumiaki; Seki, Shinichiro; Tsubakimoto, Maho; Sugimura, Kazuro

    2014-01-01

    Purpose: To prospectively and directly compare oxygen-enhanced (O 2 -enhanced) MRI with thin-section CT for pulmonary functional loss and disease severity assessment in connective tissue disease (CTD) patients with interstitial lung disease (ILD). Materials and methods: Thin-section CT, O 2 -enhanced MRI, pulmonary function test and serum KL-6 were administered to 36 CTD patients with ILD (23 men, 13 women; mean age: 63.9 years) and nine CTD patients without ILD (six men, and three women; mean age: 62.0 years). A relative-enhancement ratio (RER) map was generated from O 2 -enhanced MRI and mean relative enhancement ratio (MRER) for each subject was calculated from all ROI measurements. CT-assessed disease severity was evaluated with a visual scoring system from each of the thin-section CT data. MRER and CT-assessed disease severities of CTD patients with and without ILD were then statistically compared. To assess capability for pulmonary functional loss and disease severity assessment in CTD patients, correlations of MRER and CT-assessed disease severity with pulmonary functional parameters and serum KL-6 in all subjects were statistically determined. Results: MRER and CT-assessed disease severity showed significant differences between CTD patients with (MRER: 0.15 ± 0.08, CT-assessed disease severity: 13.0 ± 7.4%) and without ILD (MRER: 0.25 ± 0.06, p = 0.0011; CT-assessed disease severity: 1.6 ± 1.6%, p < 0.0001). MRER and CT-assessed disease severity correlated significantly with pulmonary functional parameters and serum KL-6 in all subjects (0.61 ≤ r ≤ 0.79, p < 0.05). Conclusion: O 2 -enhanced MRI was found to be as useful as thin-section CT for pulmonary functional loss and disease severity assessment of CTD patients with ILD

  2. A near infrared instrument to monitor relative hemoglobin concentrations of human bone tissue in vitro and in vivo

    Science.gov (United States)

    Aziz, Syed Mahfuzul; Khambatta, Faram; Vaithianathan, Tharshan; Thomas, John C.; Clark, Jillian M.; Marshall, Ruth

    2010-04-01

    A continuous wave near infrared instrument has been developed to monitor in vivo changes in the hemoglobin concentration of the trabecular compartment of human bone. The transmitter uses only two laser diodes of wavelengths 685 and 830 nm, and the receiver uses a single silicon photodiode operating in the photovoltaic mode. The functioning of the instrument and the depth of penetration of the near infrared signals was determined in vitro using tissue-equivalent phantoms. The instrument achieves a depth of penetration of approximately 2 cm for an optode separation of 4 cm and, therefore, has the capacity to interrogate the trabecular compartment of human bone. The functioning of the instrument was tested in vivo to evaluate the relative oxy-hemoglobin (HbO2) and deoxy-hemoglobin (Hb) concentrations of the proximal tibial bone of apparently healthy, normal weight, adult subjects in response to a 3 min on, 5 min off, vascular occlusion protocol. The traces of the relative Hb and HbO2 concentrations obtained were reproducible in controlled conditions. The instrument is relatively simple and flexible, and offers an inexpensive platform for further studies to obtain normative data for healthy cohorts, and to evaluate disease-specific performance characteristics for cohorts with vasculopathies of bone.

  3. Biomass characterization by dielectric monitoring of viability and oxygen uptake rate measurements in a novel membrane bioreactor.

    Science.gov (United States)

    Shariati, Farshid Pajoum; Heran, Marc; Sarrafzadeh, Mohammad Hossein; Mehrnia, Mohammad Reza; Sarzana, Gabriele; Ghommidh, Charles; Grasmick, Alain

    2013-07-01

    The application of permittivity and oxygen uptake rate (OUR) as biological process control parameters in a wastewater treatment system was evaluated. Experiments were carried out in a novel airlift oxidation ditch membrane bioreactor under different organic loading rates (OLR). Permittivity as representative of activated sludge viability was measured by a capacitive on-line sensor. OUR was also measured as a representative for respirometric activity. Results showed that the biomass concentration increases with OLR and all biomass related measurements and simulators such as MLSS, permittivity, OUR, ASM1 and ASM3 almost follow the same increasing trends. The viability of biomass decreased when the OLR was reduced from 5 to 4 kg COD m(-3)d(-1). During decreasing of OLR, biomass related parameters generally decreased but not in a similar manner. Also, protein concentration in the system during OLR decreasing changed inversely with the activated sludge viability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Flame-Oxidized Stainless-Steel Anode as a Probe in Bioelectrochemical System-Based Biosensors to Monitor the Biochemical Oxygen Demand of Wastewater

    Directory of Open Access Journals (Sweden)

    Qiaochu Liang

    2018-02-01

    Full Text Available Biochemical oxygen demand (BOD is a widely used index of water quality in wastewater treatment; however, conventional measurement methods are time-consuming. In this study, we analyzed a novel flame-oxidized stainless steel anode (FO-SSA for use as the probe of bioelectrochemical system (BES-based biosensors to monitor the BOD of treated swine wastewater. A thinner biofilm formed on the FO-SSA compared with that on a common carbon-cloth anode (CCA. The FO-SSA was superior to the CCA in terms of rapid sensing; the response time of the FO-SSA to obtain the value of R2 > 0.8 was 1 h, whereas the CCA required 4 h. These results indicate that the FO-SSA offers better performance than traditional CCAs in BES biosensors and can be used to improve biomonitoring of wastewater.

  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. A simple and rapid method for monitoring dissolved oxygen in water with a submersible microbial fuel cell (SBMFC)

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Angelidaki, Irini

    2012-01-01

    Asubmersiblemicrobial fuel cell (SBMFC) was developed as a biosensor forin situand real time monitoring of dissolvedoxygen (DO) in environmental waters. Domestic wastewater was utilized as sole fuel for powering the sensor. The sensor performance was firstly examined with tap water at varying DO...... the sensing activities. The sensor ability was further explored under different environmental conditions (e.g., pH, temperature, conductivity, alternative electron acceptor), and the results indicated that a calibration would be required before field application. Lastly, the sensor was tested with different...

  7. A multiplexed electronic architecture for opto-electronic patch sensor to effectively monitor heart rate and oxygen saturation

    Science.gov (United States)

    Yan, Liangwen; Hu, Sijung; Alharbi, Samah; Blanos, Panagiotis

    2018-02-01

    To effectively capture human vital signs, a multi-wavelength optoelectronic patch sensor (MOEPS), together with a schematic architecture of electronics, was developed to overcome the drawbacks of present photoplethysmographic (PPG) sensors. To obtain a better performance of in vivo physiological measurement, the optimal illuminations, i.e., light emitting diodes (LEDs) in the MOEPS, whose wavelength is automatically adjusted to each specific subject, were selected to capture better PPG signals. A multiplexed electronic architecture has been well established to properly drive the MOEPS and effectively capture pulsatile waveforms at rest. The protocol was designed to investigate its performance with the participation of 11 healthy subjects aged between 18 and 30. The signals obtained from green (525nm) and orange (595nm) illuminations were used to extract heart rate (HR) and oxygen saturation (SpO2%). These results were compared with data, simultaneously acquired, from a commercial ECG and a pulse oximeter. Considering the difficulty for current devices to attain the SpO2%, a new computing method, to obtain the value of SpO2%, is proposed depended on the green and orange wavelength illuminations. The values of SpO2% between the MOEPS and the commercial Pulse Oximeter devics showed that the results were in good agreement. The values of HR showed close correlation between commercial devices and the MOEPS (HR: r1=0.994(Green); r2=0.992(Orange); r3=0.975(Red); r4=0.990(IR)).

  8. A Quantitative Method to Monitor Reactive Oxygen Species Production by Electron Paramagnetic Resonance in Physiological and Pathological Conditions

    Science.gov (United States)

    Mrakic-Sposta, Simona; Gussoni, Maristella; Montorsi, Michela; Porcelli, Simone; Vezzoli, Alessandra

    2014-01-01

    The growing interest in the role of Reactive Oxygen Species (ROS) and in the assessment of oxidative stress in health and disease clashes with the lack of consensus on reliable quantitative noninvasive methods applicable. The study aimed at demonstrating that a recently developed Electron Paramagnetic Resonance microinvasive method provides direct evidence of the “instantaneous” presence of ROS returning absolute concentration levels that correlate with “a posteriori” assays of ROS-induced damage by means of biomarkers. The reliability of the choice to measure ROS production rate in human capillary blood rather than in plasma was tested (step I). A significant (P < 0.01) linear relationship between EPR data collected on capillary blood versus venous blood (R 2 = 0.95), plasma (R 2 = 0.82), and erythrocytes (R 2 = 0.73) was found. Then (step II) ROS production changes of various subjects' categories, young versus old and healthy versus pathological at rest condition, were found significantly different (range 0.0001–0.05 P level). The comparison of the results with antioxidant capacity and oxidative damage biomarkers concentrations showed that all changes indicating increased oxidative stress are directly related to ROS production increase. Therefore, the adopted method may be an automated technique for a lot of routine in clinical trials. PMID:25374651

  9. Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

    Science.gov (United States)

    Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

    2016-05-31

    Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

  10. A 2-week pretreatment with 13-cis-retinoic acid + interferon-α-2a prior to definitive radiation improves tumor tissue oxygenation in cervical cancers

    International Nuclear Information System (INIS)

    Dunst, J.; Haensgen, G.; Becker, A.; Krause, U.; Fuechsel, G.; Koehler, U.

    1998-01-01

    Background: We have evaluated the tumor tissue pO 2 in cervical cancers in patients treated with 13-cis-retinoic acid and interferon-α-2a prior to and during radiotherapy. Patients and methods: From June 1995 through April 1997, 22 patients with squamous cell carcinoma FIGO IIB/III of the cervix who were scheduled for definitive radiotherapy with curative intent received additional treatment with 13-cis-retinoic acid (cRA, isotretinoin) plus interferon-α-2a (IFN-α-2a) as part of a phase-II protocol. cRA/IFN-α-2a started 14 days prior to radiotherapy (1 mg per kilogramme body weight cRA orally daily plus 6x10 6 IU IFN-α-2a subcutaneously daily). After this indicution period, standard radiotherapy was administered (external irradiation with 50.4 Gy in 28 fractions of 1.8 Gy plus HDR-brachytherapy). During radiotherapy, cRA/IFN-α-2a-treatment was continued with 50% of the daily doses. Tumor tissue pO 2 -measurements were performed prior to and after the cRA/IFN-induction period as well as at 20 Gy and at the end of radiotherapy with an Eppendorf-pO 2 -histograph. Results: In 11 out of the 22 patients, pO 2 -measurements were performed prior to the cRA/IFN-induction therapy. The median pO 2 of these untreated tumors was 17.7±16.3 mm Hg. The relative frequency of hypoxic readings with pO 2 -values below 5 mm Hg ranged from 0% to 60.6% (mean 24.3±21.0%). After the 2-week induction period with cRA/IFN, the median pO 2 had increased from 17.7pm16.3 mm Hg to 27.6±19.1 mm Hg (not significant). In all 5 patients with hypoxic tumors prior to cRA/IFN (median pO 2 of 10 mm Hg or less), the median pO 2 was above 20 mm Hg after the 2-week cRA/IFN-induction. In this subgroup of hypoxic tumors, the median pO 2 increased from 6.3±2.7 mm Hg to 27.0±5.6 mm Hg (p=0.004, t-test for paired samples). The frequency of hypoxic readings (pO 2 -values 2 below 10 mm Hg prior to treatment), 4/5 achieved complete remission. Conclusions: Pretreatment with cRA/IFN improves oxygenation of

  11. Validation of a Radiography-Based Quantification Designed to Longitudinally Monitor Soft Tissue Calcification in Skeletal Muscle.

    Science.gov (United States)

    Moore, Stephanie N; Hawley, Gregory D; Smith, Emily N; Mignemi, Nicholas A; Ihejirika, Rivka C; Yuasa, Masato; Cates, Justin M M; Liu, Xulei; Schoenecker, Jonathan G

    2016-01-01

    Soft tissue calcification, including both dystrophic calcification and heterotopic ossification, may occur following injury. These lesions have variable fates as they are either resorbed or persist. Persistent soft tissue calcification may result in chronic inflammation and/or loss of function of that soft tissue. The molecular mechanisms that result in the development and maturation of calcifications are uncertain. As a result, directed therapies that prevent or resorb soft tissue calcifications remain largely unsuccessful. Animal models of post-traumatic soft tissue calcification that allow for cost-effective, serial analysis of an individual animal over time are necessary to derive and test novel therapies. We have determined that a cardiotoxin-induced injury of the muscles in the posterior compartment of the lower extremity represents a useful model in which soft tissue calcification develops remote from adjacent bones, thereby allowing for serial analysis by plain radiography. The purpose of the study was to design and validate a method for quantifying soft tissue calcifications in mice longitudinally using plain radiographic techniques and an ordinal scoring system. Muscle injury was induced by injecting cardiotoxin into the posterior compartment of the lower extremity in mice susceptible to developing soft tissue calcification. Seven days following injury, radiographs were obtained under anesthesia. Multiple researchers applied methods designed to standardize post-image processing of digital radiographs (N = 4) and quantify soft tissue calcification (N = 6) in these images using an ordinal scoring system. Inter- and intra-observer agreement for both post-image processing and the scoring system used was assessed using weighted kappa statistics. Soft tissue calcification quantifications by the ordinal scale were compared to mineral volume measurements (threshold 450.7mgHA/cm3) determined by μCT. Finally, sample-size calculations necessary to discriminate

  12. Waterlogging tolerance, tissue nitrogen and oxygen transport in the forage legume Melilotus siculus: a comparison of nodulated and nitrate-fed plants.

    Science.gov (United States)

    Konnerup, Dennis; Toro, Guillermo; Pedersen, Ole; Colmer, Timothy David

    2018-03-14

    Soil waterlogging adversely impacts most plants. Melilotus siculus is a waterlogging-tolerant annual forage legume, but data were lacking for the effects of root-zone hypoxia on nodulated plants reliant on N2 fixation. The aim was to compare the waterlogging tolerance and physiology of M. siculus reliant on N2 fixation or with access to NO3-. A factorial experiment imposed treatments of water level (drained or waterlogged), rhizobia (nil or inoculated) and mineral N supply (nil or 11 mm NO3-) for 21 d on plants in pots of vermiculite in a glasshouse. Nodulation, shoot and root growth and tissue N were determined. Porosity (gas volume per unit tissue volume) and respiration rates of root tissues and nodules, and O2 microelectrode profiling across nodules, were measured in a second experiment. Plants inoculated with the appropriate rhizobia, Ensifer (syn. Sinorhizobium) medicae, formed nodules. Nodulated plants grew as well as plants fed NO3-, both in drained and waterlogged conditions. The growth and total N content of nodulated plants (without any NO3- supplied) indicated N2 fixation. Respiration rates (mass basis) were highest in nodules and root tips and lowest in basal root tissues. Secondary aerenchyma (phellem) formed along basal root parts and a thin layer of this porous tissue also covered nodules, which together enhanced gas-phase diffusion of O2 to the nodules; O2 was below detection within the infected zone of the nodule interior. Melilotus siculus reliant on N2 fixation grew well both in drained and waterlogged conditions, and had similar tissue N concentrations. In waterlogged conditions the relatively high respiration rates of nodules must rely on O2 movement via the aerenchymatous phellem in hypocotyl, roots and the outer tissue layers of nodules.

  13. DETERMINATION OF CADMIUM IN EDIBLE TISSUES OF CRABS CATCH IN ITALIAN TERITORIAL WATERS: MONITORING ON EMILIA ROMAGNA REGION

    Directory of Open Access Journals (Sweden)

    M. D’Antonio

    2011-01-01

    Full Text Available On 2008 there was a Community alert concerning the presence of Cadmium in crabs and on December 2009 there was a note from the Italian Ministry of Health concerning the control of cadmium in edible tissues of crabs caught in Italian territorial waters. This laboratory analyzed a total of 32 samples of crabs by atomic absorption spectroscopy graphite stove dividing the crustaceans in the following tissues: bright parts contained in claws, dark parts contained in the shell and red parts contained in the shell. The results showed that gastrointestinal shellfish tissues is at greatest risk, while the bright parts contained in claws are always below the limit set by European legislation (Reg. 1881/2006 and following. Furthermore it is clear that the crustaceans caught in the northern Adriatic present values of cadmium significantly lower compared to shellfish from France and UK.

  14. Oxygen toxicity

    Directory of Open Access Journals (Sweden)

    C. A. van der Westhuizen

    1990-07-01

    Full Text Available Oxygen has been discovered about 200 years ago. Since then the vital physiological involvement of oxygen in various biologi­cal processes, mainly energy production, has been established. However, in the body molecular oxygen can be converted to toxic oxygen metabolites such as superoxide anion, hydrogen peroxide, the hydroxyl radical and singlet oxygen. These toxic metabolites are produced mainly in the mitochondria, plasma membranes and endoplasmic reticulum.

  15. A novel mouse model of soft-tissue infection using bioluminescence imaging allows noninvasive, real-time monitoring of bacterial growth.

    Science.gov (United States)

    Yoshioka, Kenji; Ishii, Ken; Kuramoto, Tetsuya; Nagai, Shigenori; Funao, Haruki; Ishihama, Hiroko; Shiono, Yuta; Sasaki, Aya; Aizawa, Mamoru; Okada, Yasunori; Koyasu, Shigeo; Toyama, Yoshiaki; Matsumoto, Morio

    2014-01-01

    Musculoskeletal infections, including surgical-site and implant-associated infections, often cause progressive inflammation and destroy areas of the soft tissue. Treating infections, especially those caused by multi-antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Although there are a few animal models that enable the quantitative evaluation of infection in soft tissues, these models are not always reproducible or sustainable. Here, we successfully established a real-time, in vivo, quantitative mouse model of soft-tissue infection in the superficial gluteus muscle (SGM) using bioluminescence imaging. A bioluminescent strain of MRSA was inoculated into the SGM of BALB/c adult male mice, followed by sequential measurement of bacterial photon intensity and serological and histological analyses of the mice. The mean photon intensity in the mice peaked immediately after inoculation and remained stable until day 28. The serum levels of interleukin-6, interleukin-1 and C-reactive protein at 12 hours after inoculation were significantly higher than those prior to inoculation, and the C-reactive protein remained significantly elevated until day 21. Histological analyses showed marked neutrophil infiltration and abscesses containing necrotic and fibrous tissues in the SGM. With this SGM mouse model, we successfully visualized and quantified stable bacterial growth over an extended period of time with bioluminescence imaging, which allowed us to monitor the process of infection without euthanizing the experimental animals. This model is applicable to in vivo evaluations of the long-term efficacy of novel antibiotics or antibacterial implants.

  16. Assessment and Use of Optical Oxygen Sensors as Tools to Assist in Optimal Product Component Selection for the Development of Packs of Ready-to-Eat Mixed Salads and for the Non-Destructive Monitoring of in-Pack Oxygen Levels Using Chilled Storage.

    Science.gov (United States)

    Hempel, Andreas W; O'Sullivan, Maurice G; Papkovsky, Dmitri B; Kerry, Joseph P

    2013-05-22

    Optical oxygen sensors were used to ascertain the level of oxygen consumed by individual salad leaves for optimised packaging of ready-to-eat (RTE) Italian salad mixes during refrigerated storage. Seven commonly found leaves in Italian salad mixes were individually assessed for oxygen utilisation in packs. Each leaf showed varying levels of respiration throughout storage. Using the information obtained, an experimental salad mix was formulated (termed Mix 3) which consisted of the four slowest respiring salad leaves-Escarole, Frisee, Red Batavia, Lollo Rosso. Mix 3 was then compared against two commercially available Italian salads; Mix 1 (Escarole, Frisee, Radicchio, Lollo Rosso) and Mix 2 (Cos, Frisee, Radicchio, Lollo Rosso). Optical sensors were used to non-destructively monitor oxygen usage in all mixes throughout storage. In addition to oxygen consumption, all three salad mixes were quality assessed in terms of microbial load and sensorial acceptability. In conclusion, Mix 3 was found to consume the least amount of oxygen over time, had the lowest microbial load and was most sensorially preferred ( p products.

  17. Four-years experience with monitoring of persons at the treatment of children patients with neuroblastoma by 131I-MIBG combination with hyperbaric oxygen therapy

    International Nuclear Information System (INIS)

    Hermanska, J.; Zimak, J.; Paskova, Z.; Dosel, P.

    2001-01-01

    Treatment of children patients with neuroblastoma by 131 I-MIBG in combination with hyperbaric oxygen therapy (HBO) started in the Czech Republic in 1997. Estimation of radiation load from extemal irradiation plays very important role in the treatment scheme elaborated at the Department of Nuclear Medicine. According to this scheme, activities of 5.5 GBq and 3.7 GBq are administered at the first and repeated therapies,respectively. 3 rd , 4 th , 5 th and 6 th day after the administration patients undergo HBO in the Institute of Aviation Medicine Prague. Activity administration and following care are realised at the bed station of the Department of Nuclear Medicine, which is the workplace of III. category with unsealed radionuclide sources. Real dose equivalents were checked during the reported four-year period. Members of both groups were equipped by personal digital dosemeters STEPHEN 6000 for inspection. From the presented results, the following conclusions can be drawn: (1) Monitoring of family members has to be performed in spite of the fact that exceeding of equivalent dose of 5 mSv is non-realistic. Unexpected situation concerning behaviour of both parents and children cannot be excluded. Moreover, records of H-values have to be stored and analysed in the case of possible pregnancy. (2) A question arises in connection with the special limit 5 mSv: What is the whole time of the treatment? Is it possible to understand it, similarly as in the case of iodine therapy, as 5 mSv per year or is it necessary to take into account really the whole, often very long, time of the treatment? (3) Monitoring of the staff maintaining the hyperbaric chamber and ambulance drivers seems to be unnecessary. Under normal condition, the staff is outside the chamber and its contact with a patient is minimal. In unusual situation, the instructed nurse from the Department of Nuclear Medicine equipped by STEPHEN 6000 will estimate dose equivalent and contact responsible medical

  18. Non-invasive transdermal two-dimensional mapping of cutaneous oxygenation with a rapid-drying liquid bandage.

    Science.gov (United States)

    Li, Zongxi; Roussakis, Emmanuel; Koolen, Pieter G L; Ibrahim, Ahmed M S; Kim, Kuylhee; Rose, Lloyd F; Wu, Jesse; Nichols, Alexander J; Baek, Yunjung; Birngruber, Reginald; Apiou-Sbirlea, Gabriela; Matyal, Robina; Huang, Thomas; Chan, Rodney; Lin, Samuel J; Evans, Conor L

    2014-11-01

    Oxygen plays an important role in wound healing, as it is essential to biological functions such as cell proliferation, immune responses and collagen synthesis. Poor oxygenation is directly associated with the development of chronic ischemic wounds, which affect more than 6 million people each year in the United States alone at an estimated cost of $25 billion. Knowledge of oxygenation status is also important in the management of burns and skin grafts, as well as in a wide range of skin conditions. Despite the importance of the clinical determination of tissue oxygenation, there is a lack of rapid, user-friendly and quantitative diagnostic tools that allow for non-disruptive, continuous monitoring of oxygen content across large areas of skin and wounds to guide care and therapeutic decisions. In this work, we describe a sensitive, colorimetric, oxygen-sensing paint-on bandage for two-dimensional mapping of tissue oxygenation in skin, burns, and skin grafts. By embedding both an oxygen-sensing porphyrin-dendrimer phosphor and a reference dye in a liquid bandage matrix, we have created a liquid bandage that can be painted onto the skin surface and dries into a thin film that adheres tightly to the skin or wound topology. When captured by a camera-based imaging device, the oxygen-dependent phosphorescence emission of the bandage can be used to quantify and map both the pO2 and oxygen consumption of the underlying tissue. In this proof-of-principle study, we first demonstrate our system on a rat ischemic limb model to show its capabilities in sensing tissue ischemia. It is then tested on both ex vivo and in vivo porcine burn models to monitor the progression of burn injuries. Lastly, the bandage is applied to an in vivo porcine graft model for monitoring the integration of full- and partial-thickness skin grafts.

  19. Real time monitoring and quantification of reactive oxygen species in breast cancer cell line MCF-7 by 2',7'-dichlorofluorescin diacetate (DCFDA) assay.

    Science.gov (United States)

    Figueroa, Daniela; Asaduzzaman, Mohammad; Young, Fiona

    2018-04-07

    The detection of reactive oxygen species (ROS) using 2',7'-dichlorofluorescin diacetate (DCFDA) is commonly performed by a single measurement of fluorescence but this fails to capture a profile of ROS generation over time. This study aimed to develop a real-time monitoring method to increase the utility of the assay, to incorporate cytotoxicity screening and to describe the combined effects of DCFDA and the ROS generator, Ter-butyl hydrogen peroxide (TBHP). Breast cancer MCF-7 cells were loaded with DCFDA (0-50 μM) for 45 min, and then exposed to TBHP (0-50 μM). Fluorescence was recorded according to three different schedules: every hour for 6 h, or once after 6 h or 24 h. Viability was assessed in a crystal violet assay and cell morphology was examined by microscopy. TBHP caused a time and dose-dependent increase in ROS and the magnitude of the fluorescent signal was affected by the loading concentration of DCFDA. Reading the fluorescence every hour for 6 h did not diminish the emission signal. The most sensitive and reliable combination for this ROS assay was 10 μM DCFDA with 25 μM TBHP; since higher concentrations of DCFDA compromised cell viability. In conclusion we adapted a single point ROS assay to enable production of a profile of ROS generation over an extended 6 h period, and related this to cell viability and morphology. Published by Elsevier Inc.

  20. Making sense of monitoring data using Jupyter Notebooks: a case study of dissolved oxygen dynamics across a fresh-estuarine gradient

    Science.gov (United States)

    Nelson, N.; Munoz-Carpena, R.

    2016-12-01

    In the presented exercise, students (advanced undergraduate-graduate) explore dissolved oxygen (DO) dynamics at three locations along a fresh-estuarine gradient of the Lower St. Johns River, FL (USA). Spatiotemporal DO trends along this gradient vary as a function of (1) tidal influence, and (2) biotic productivity (phytoplankton photosynthesis and community respiration). This combination of influences produces distinct DO behavior across each of the three hydrologically-connected sites. Through analysis of high frequency monitoring data, students are encouraged to think critically about the roles of physical and biological drivers of DO, and how the relative importance of these factors can vary among different locations within a single tidal waterbody. Data from each of the three locations along the river are downloaded with CUAHSI HydroClient, and analysis is performed with a Python-enabled Jupyter Notebook that has been specifically created for this assignment. Jupyter Notebooks include annotated code organized into blocks that are executed one-at-a-time; this format is amenable to classroom teaching, and provides an approachable introduction to Python for inexperienced coders. The outputs from each code block (i.e. graphs, tables) are produced within the Jupyter Notebook, thus allowing students to directly interact with the code. Expected student learning outcomes include increased spatial reasoning, as well as greater understanding of DO cycling, spatiotemporal variability in tidal systems, and challenges associated with collecting and evaluating large data sets. Specific technical learning outcomes include coding in Python for data management and analysis using Jupyter notebooks. This assignment and associated materials are open-access and available on the Science Education Resource Center website.

  1. Simultaneous multi-depth assessment of tissue oxygen saturation in thenar and forearm using near-infrared spectroscopy during a simple cardiovascular challenge

    NARCIS (Netherlands)

    Bezemer, Rick; Karemaker, John M.; Klijn, Eva; Martin, Daniel; Mitchell, Kay; Grocott, Mike; Heger, Michal; Ince, Can

    2009-01-01

    INTRODUCTION: Hypovolemia and hypovolemic shock are life-threatening conditions that occur in numerous clinical scenarios. Near-infrared spectroscopy (NIRS) has been widely explored, successfully and unsuccessfully, in an attempt to use it as an early detector of hypovolemia by measuring tissue

  2. 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

  3. Real-time monitoring of nitric oxide (NO) and pO2 levels under ischemic conditions associated with small bowel ischemia/reperfusion injury using selective electrodes for NO and oxygen molecules.

    Science.gov (United States)

    Watanabe, T; Owada, S; Kobayashi, H; Ishiuchi, A; Nakano, H; Asakuta, T; Shimamura, T; Asano, T; Koizumi, S; Jinnouchi, Y; Katayama, M; Kamibayasi, M; Murakami, E; Otsubo, T

    2007-12-01

    The present study demonstrated the feasibility of monitoring nitric oxide (NO) and pO2 levels under ischemic conditions associated with small bowel ischemia/reperfusion (I/R) injury through the use of selective electrodes for NO and oxygen molecules. NO levels gradually increased during ischemia. When reperfusion was started, the NO level decreased suddenly and returned to pre-ischemia values within 10 minutes. After clamping, pO2 decreased rapidly. When reperfusion was started, pO2 increased suddenly, returning to pre-ischemia values within 10 minutes. We concluded that it is feasible to monitor NO and pO2 levels under ischemic conditions of small bowel I/R injury through the use of electrodes selective for NO and oxygen molecules.

  4. Tissue- and Cell-Specific Cytokinin Activity in Populus × canescens Monitored by ARR5::GUS Reporter Lines in Summer and Winter.

    Science.gov (United States)

    Paul, Shanty; Wildhagen, Henning; Janz, Dennis; Teichmann, Thomas; Hänsch, Robert; Polle, Andrea

    2016-01-01

    Cytokinins play an important role in vascular development. But knowledge on the cellular localization of this growth hormone in the stem and other organs of woody plants is lacking. The main focus of this study was to investigate the occurrence and cellular localization of active cytokinins in leaves, roots, and along the stem of Populus × canescens and to find out how the pattern is changed between summer and winter. An ARR5::GUS reporter construct was used to monitor distribution of active cytokinins in different tissues of transgenic poplar lines. Three transgenic lines tested under outdoor conditions showed no influence of ARR5::GUS reporter construct on the growth performance compared with the wild-type, but one line lost the reporter activity. ARR5::GUS activity indicated changes in the tissue- and cell type-specific pattern of cytokinin activity during dormancy compared with the growth phase. ARR5::GUS activity, which was present in the root tips in the growing season, disappeared in winter. In the stem apex ground tissue, ARR5::GUS activity was higher in winter than in summer. Immature leaves from tissue-culture grown plants showed inducible ARR5::GUS activity. Leaf primordia in summer showed ARR5::GUS activity, but not the expanded leaves of outdoor plants or leaf primordia in winter. In stem cross sections, the most prominent ARR5::GUS activity was detected in the cortex region and in the rays of bark in summer and in winter. In the cambial zone the ARR5::GUS activity was more pronounced in the dormant than in growth phase. The pith and the ray cells adjacent to the vessels also displayed ARR5::GUS activity. In silico analyses of the tissue-specific expression patterns of the whole PtRR type-A family of poplar showed that PtRR10, the closest ortholog to the Arabidopsis ARR5 gene, was usually the most highly expressed gene in all tissues. In conclusion, gene expression and tissue-localization indicate high activity of cytokinins not only in summer, but

  5. Application of single- and dual-energy CT brain tissue segmentation to PET monitoring of proton therapy

    Science.gov (United States)

    Berndt, Bianca; Landry, Guillaume; Schwarz, Florian; Tessonnier, Thomas; Kamp, Florian; Dedes, George; Thieke, Christian; Würl, Matthias; Kurz, Christopher; Ganswindt, Ute; Verhaegen, Frank; Debus, Jürgen; Belka, Claus; Sommer, Wieland; Reiser, Maximilian; Bauer, Julia; Parodi, Katia

    2017-03-01

    The purpose of this work was to evaluate the ability of single and dual energy computed tomography (SECT, DECT) to estimate tissue composition and density for usage in Monte Carlo (MC) simulations of irradiation induced β + activity distributions. This was done to assess the impact on positron emission tomography (PET) range verification in proton therapy. A DECT-based brain tissue segmentation method was developed for white matter (WM), grey matter (GM) and cerebrospinal fluid (CSF). The elemental composition of reference tissues was assigned to closest CT numbers in DECT space (DECTdist). The method was also applied to SECT data (SECTdist). In a validation experiment, the proton irradiation induced PET activity of three brain equivalent solutions (BES) was compared to simulations based on different tissue segmentations. Five patients scanned with a dual source DECT scanner were analyzed to compare the different segmentation methods. A single magnetic resonance (MR) scan was used for comparison with an established segmentation toolkit. Additionally, one patient with SECT and post-treatment PET scans was investigated. For BES, DECTdist and SECTdist reduced differences to the reference simulation by up to 62% when compared to the conventional stoichiometric segmentation (SECTSchneider). In comparison to MR brain segmentation, Dice similarity coefficients for WM, GM and CSF were 0.61, 0.67 and 0.66 for DECTdist and 0.54, 0.41 and 0.66 for SECTdist. MC simulations of PET treatment verification in patients showed important differences between DECTdist/SECTdist and SECTSchneider for patients with large CSF areas within the treatment field but not in WM and GM. Differences could be misinterpreted as PET derived range shifts of up to 4 mm. DECTdist and SECTdist yielded comparable activity distributions, and comparison of SECTdist to a measured patient PET scan showed improved agreement when compared to SECTSchneider. The agreement between predicted and measured PET

  6. Field metabolic rate and PCB adipose tissue deposition efficiency in East Greenland polar bears derived from contaminant monitoring data.

    Science.gov (United States)

    Pavlova, Viola; Nabe-Nielsen, Jacob; Dietz, Rune; Svenning, Jens-Christian; Vorkamp, Katrin; Rigét, Frank Farsø; Sonne, Christian; Letcher, Robert J; Grimm, Volker

    2014-01-01

    Climate change will increasingly affect the natural habitat and diet of polar bears (Ursus maritimus). Understanding the energetic needs of polar bears is therefore important. We developed a theoretical method for estimating polar bear food consumption based on using the highly recalcitrant polychlorinated biphenyl (PCB) congener, 2,2',4,4',55-hexaCB (CB153) in bear adipose tissue as an indicator of food intake. By comparing the CB153 tissue concentrations in wild polar bears with estimates from a purposely designed individual-based model, we identified the possible combinations of field metabolic rates (FMR) and CB153 deposition efficiencies in East Greenland polar bears. Our simulations indicate that if 30% of the CB153 consumed by polar bear individuals were deposited into their adipose tissue, the corresponding FMR would be only two times the basal metabolic rate. In contrast, if the modelled CB153 deposition efficiency were 10%, adult polar bears would require six times more energy than that needed to cover basal metabolism. This is considerably higher than what has been assumed for polar bears in previous studies though it is similar to FMRs found in other marine mammals. An implication of this result is that even relatively small reductions in future feeding opportunities could impact the survival of East Greenland polar bears.

  7. Field metabolic rate and PCB adipose tissue deposition efficiency in East Greenland polar bears derived from contaminant monitoring data.

    Directory of Open Access Journals (Sweden)

    Viola Pavlova

    Full Text Available Climate change will increasingly affect the natural habitat and diet of polar bears (Ursus maritimus. Understanding the energetic needs of polar bears is therefore important. We developed a theoretical method for estimating polar bear food consumption based on using the highly recalcitrant polychlorinated biphenyl (PCB congener, 2,2',4,4',55-hexaCB (CB153 in bear adipose tissue as an indicator of food intake. By comparing the CB153 tissue concentrations in wild polar bears with estimates from a purposely designed individual-based model, we identified the possible combinations of field metabolic rates (FMR and CB153 deposition efficiencies in East Greenland polar bears. Our simulations indicate that if 30% of the CB153 consumed by polar bear individuals were deposited into their adipose tissue, the corresponding FMR would be only two times the basal metabolic rate. In contrast, if the modelled CB153 deposition efficiency were 10%, adult polar bears would require six times more energy than that needed to cover basal metabolism. This is considerably higher than what has been assumed for polar bears in previous studies though it is similar to FMRs found in other marine mammals. An implication of this result is that even relatively small reductions in future feeding opportunities could impact the survival of East Greenland polar bears.

  8. Simultaneous determination of β-agonists and monitoring in bovine tissues by liquid chromatography-tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Kyunghun Jeong

    2018-01-01

    Full Text Available The misuse of β-agonists leads to a potential risk to public health and is forbidden in many countries. We developed a rapid, sensitive and reliable multi-residue detection method for zilpaterol, ractopamine, and clenbuterol in bovine tissues by liquid chromatography–tandem mass spectrometry. Residues were extracted in ethyl acetate after protein precipitation, and then analyzed by the developed method. Good linearities (R2 > 0.99 were observed, and the recoveries of zilpaterol, ractopamine, and clenbuterol were 99%, 74%, and 102%, respectively. The limits of quantitation for zilpaterol, ractopamine, and clenbuterol were 1.3, 5.0, and 1.7 ng/g, respectively. The method is also applied successfully to bovine tissues within the Korean National Residue Programme. None of the 3 β-agonists were detected from 50 domestic samples. However, zilpaterol (6.3 ng/g was quantified in one out of the 50 imported samples. The application of this method will be helpful in quality control analysis of β-agonists residues in bovine tissues.

  9. Interpretation of sequential measurements of cancer antigen 125 (CA 125), carcinoembryonic antigen (CEA), and tissue polypeptide antigen (TPA) based on analytical imprecision and biological variation in the monitoring of ovarian cancer

    DEFF Research Database (Denmark)

    Tuxen, Malgorzata K.; Sölétormos, G; Petersen, P H

    2001-01-01

    The main objective with cancer antigen 125 (CA 125), carcinoembryonic antigen (CEA), and tissue polypeptide antigen (TPA) monitoring of ovarian cancer patients is to detect an early change of disease activity with high reliability. We hypothesized that a monitoring scheme for ovarian cancer patie...

  10. The efficacy of hyperbaric oxygen in modifying the response of tissue to irradiation in doses of 200-400 rad per fraction

    International Nuclear Information System (INIS)

    Suit, D.D.; Orsi, L.

    1975-01-01

    The efficacy of respiration of O 2 at 30 psi in modifying the response of normal and tumour tissue to irradiation administered at 200 to 400 rad per fraction to anaesthetized mice has been evaluated. End-points have been delay in growth and TCD 50 for an early generation iso-transplant of a C 3 H mouse mammary carcinoma, and the acute reaction of skin of the C 3 H/Sed mouse. Results showed that the ratios of dose (air)/dose (O 2 30 psi) to elicit these end points were in the range 1.2 to 1.4. In earlier work using the same end points but doses per fraction 430 to 2100 rad, the ratios were 1.6 to 1.8. That is, for these tissue responses, respiration of O 2 at 30 psi increases the response of both normal and tumour tissue to all radiation doses tested. It is of greater effectiveness when combined with large doses per fraction, eg. greater than 430 rad. (author)

  11. Oxygen Therapy

    Science.gov (United States)

    ... their breathing to dangerously low levels. Will I need oxygen when I sleep? Usually if you use supplemental oxygen during the ... your health care provider tells you you only need to use oxygen for exercise or sleep. Even if you feel “fine” off of your ...

  12. The Neuroprotection Effect of Oxygen Therapy: A Systematic Review ...

    African Journals Online (AJOL)

    2018-04-04

    Apr 4, 2018 ... investigating the neuroprotective effect of oxygen, but the outcomes as well as ...... Neuroprotective gases – Fantasy or reality for clinical use? Prog .... of oxygen on brain tissue oxygen tension in children with severe traumatic ...

  13. The effect of running versus cycling high-intensity intermittent exercise on local tissue oxygenation and perceived enjoyment in 18–30-year-old sedentary men

    Science.gov (United States)

    Solomon, Colin

    2018-01-01

    Background High-intensity interval training (HIIT) has been proposed as a time-efficient exercise format to improve exercise adherence, thereby targeting the chronic disease burden associated with sedentary behaviour. Exercise mode (cycling, running), if self-selected, will likely affect the physiological and enjoyment responses to HIIT in sedentary individuals. Differences in physiological and enjoyment responses, associated with the mode of exercise, could potentially influence the uptake and continued adherence to HIIT. It was hypothesised that in young sedentary men, local and systemic oxygen utilisation and enjoyment would be higher during a session of running HIIT, compared to a session of cycling HIIT. Methods A total of 12 sedentary men (mean ± SD; age 24 ± 3 years) completed three exercise sessions: a maximal incremental exercise test on a treadmill (MAX) followed by two experiment conditions, (1) free-paced cycling HIIT on a bicycle ergometer (HIITCYC) and (2) constant-paced running HIIT on a treadmill ergometer (HIITRUN). Deoxygenated haemoglobin (HHb) in the gastrocnemius (GN), the left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, oxygen consumption (VO2), heart rate (HR), ratings of perceived exertion (RPE) and physical activity enjoyment (PACES) were measured during HIITCYC and HIITRUN. Results There was a higher HHb in the LVL (p = 0.001) and RVL (p = 0.002) sites and a higher VO2 (p = 0.017) and HR (p HIIT produces higher levels of physiological stress when compared to constant-paced running HIIT. Participants perceived running HIIT to be more enjoyable than cycling HIIT. These findings have implications for selection of mode of HIIT for physical stress, exercise enjoyment and compliance.

  14. The effect of running versus cycling high-intensity intermittent exercise on local tissue oxygenation and perceived enjoyment in 18-30-year-old sedentary men.

    Science.gov (United States)

    Kriel, Yuri; Askew, Christopher D; Solomon, Colin

    2018-01-01

    High-intensity interval training (HIIT) has been proposed as a time-efficient exercise format to improve exercise adherence, thereby targeting the chronic disease burden associated with sedentary behaviour. Exercise mode (cycling, running), if self-selected, will likely affect the physiological and enjoyment responses to HIIT in sedentary individuals. Differences in physiological and enjoyment responses, associated with the mode of exercise, could potentially influence the uptake and continued adherence to HIIT. It was hypothesised that in young sedentary men, local and systemic oxygen utilisation and enjoyment would be higher during a session of running HIIT, compared to a session of cycling HIIT. A total of 12 sedentary men (mean ± SD; age 24 ± 3 years) completed three exercise sessions: a maximal incremental exercise test on a treadmill (MAX) followed by two experiment conditions, (1) free-paced cycling HIIT on a bicycle ergometer (HIITCYC) and (2) constant-paced running HIIT on a treadmill ergometer (HIITRUN). Deoxygenated haemoglobin (HHb) in the gastrocnemius (GN), the left vastus lateralis (LVL) and the right vastus lateralis (RVL) muscles, oxygen consumption (VO 2 ), heart rate (HR), ratings of perceived exertion (RPE) and physical activity enjoyment (PACES) were measured during HIITCYC and HIITRUN. There was a higher HHb in the LVL ( p = 0.001) and RVL ( p = 0.002) sites and a higher VO 2 ( p = 0.017) and HR ( p HIIT produces higher levels of physiological stress when compared to constant-paced running HIIT. Participants perceived running HIIT to be more enjoyable than cycling HIIT. These findings have implications for selection of mode of HIIT for physical stress, exercise enjoyment and compliance.

  15. Comparison of prostate gene expression and tissue weight changes as monitors of antiandrogen activity in GNRH-inhibited rats

    DEFF Research Database (Denmark)

    Nellemann, Christine Lydia; Lefevre, P. A.; Ashby, J.

    2003-01-01

    and Pharmacology 34:188-203, 2001], and concomitantly described changes in expression of the androgen-dependent prostatic genes PBP C3, TRPM-2, and ODC as a possible complement to gravimetric analysis of the sex accessory tissues (SAT) [Nellemann C, Vinggaard AM, Dalgaard M, Hossaini A, Larsen J-J. Toxicology 163......:29-38, 2001]. METHODS: The present study describes the results of combining these two modifications into a single assay. During the course of these experiments it was shown that SD rats gave similar results to AP rats and that the higher stimulatory dose of testosterone propionate (TP) used in our experiments...

  16. 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.

  17. Mercury in freshwater fish of northeast North America--a geographic perspective based on fish tissue monitoring databases.

    Science.gov (United States)

    Kamman, Neil C; Burgess, Neil M; Driscoll, Charles T; Simonin, Howard A; Goodale, Wing; Linehan, Janice; Estabrook, Robert; Hutcheson, Michael; Major, Andrew; Scheuhammer, Anton M; Scruton, David A

    2005-03-01

    As part of an initiative to assemble and synthesize mercury (Hg) data from environmental matrices across northeastern North America, we analyzed a large dataset comprised of 15,305 records of fish tissue Hg data from 24 studies from New York State to Newfoundland. These data were summarized to provide mean Hg concentrations for 40 fish species and associated families. Detailed analyses were carried out using data for 13 species. Hg in fishes varied by geographic area, waterbody type, and waterbody. The four species with the highest mean Hg concentrations were muskellunge (Esox masquinongy), walleye (Sander vitreus), white perch (Morone americana), and northern pike (Esox luscius). Several species displayed elevated Hg concentrations in reservoirs, relative to lakes and rivers. Normalized deviations from mean tissue levels for yellow perch (Perca flavescens) and brook trout (Salvelinus fontinalis) were mapped, illustrating how Hg concentrations in these species varied across northeastern North America. Certain geographic regions showed generally below or above-average Hg concentrations in fish, while significant heterogeneity was evident across the landscape. The proportion of waterbodies exhibiting exceedances of USEPA's criterion for fish methylmercury ranged from 14% for standard-length brook trout fillets to 42% for standard-length yellow perch fillets. A preliminary correlation analysis showed that fish Hg concentrations were related to waterbody acidity and watershed size.

  18. Optically-tracked handheld fluorescence imaging platform for monitoring skin response in the management of soft tissue sarcoma

    Science.gov (United States)

    Chamma, Emilie; Qiu, Jimmy; Lindvere-Teene, Liis; Blackmore, Kristina M.; Majeed, Safa; Weersink, Robert; Dickie, Colleen I.; Griffin, Anthony M.; Wunder, Jay S.; Ferguson, Peter C.; DaCosta, Ralph S.

    2015-07-01

    Standard clinical management of extremity soft tissue sarcomas includes surgery with radiation therapy. Wound complications (WCs) arising from treatment may occur due to bacterial infection and tissue breakdown. The ability to detect changes in these parameters during treatment may lead to earlier interventions that mitigate WCs. We describe the use of a new system composed of an autofluorescence imaging device and an optical three-dimensional tracking system to detect and coregister the presence of bacteria with radiation doses. The imaging device visualized erythema using white light and detected bacterial autofluorescence using 405-nm excitation light. Its position was tracked relative to the patient using IR reflective spheres and registration to the computed tomography coordinates. Image coregistration software was developed to spatially overlay radiation treatment plans and dose distributions on the white light and autofluorescence images of the surgical site. We describe the technology, its use in the operating room, and standard operating procedures, as well as demonstrate technical feasibility and safety intraoperatively. This new clinical tool may help identify patients at greater risk of developing WCs and investigate correlations between radiation dose, skin response, and changes in bacterial load as biomarkers associated with WCs.

  19. Monitoring of trace metals in tissues of Wallago attu (lanchi) from the Indus River as an indicator of environmental pollution.

    Science.gov (United States)

    Al-Ghanim, K A; Mahboob, Shahid; Seemab, Sadia; Sultana, S; Sultana, T; Al-Misned, Fahad; Ahmed, Z

    2016-01-01

    We aimed to assess the bioaccumulation of selected four trace metals (Cd, Ni, Zn and Co) in four tissues (muscles, skin, gills and liver) of a freshwater fish Wallago attu (lanchi) from three different sites (upstream, middle stream and downstream) of the Indus River in Mianwali district of Pakistan. Heavy metal contents in water samples and from different selected tissues of fish were examined by using flame atomic absorption spectrometry. The data were statistically compared to study the effects of the site and fish organs and their interaction on the bioaccumulation pattern of these metals at P  liver > skin > muscle. The order of bioaccumulation of these metals was Ni < Zn < Co < Cd. Heavy metal concentrations were increased during the dry season as compared to the wet season. The results of this study indicate that freshwater fish produced and marketed in Mianwali have concentrations below the standards of FEPA/WHO for these toxic metals.

  20. First-in-human pilot study of a spatial frequency domain oxygenation imaging system

    Science.gov (United States)

    Gioux, Sylvain; Mazhar, Amaan; Lee, Bernard T.; Lin, Samuel J.; Tobias, Adam M.; Cuccia, David J.; Stockdale, Alan; Oketokoun, Rafiou; Ashitate, Yoshitomo; Kelly, Edward; Weinmann, Maxwell; Durr, Nicholas J.; Moffitt, Lorissa A.; Durkin, Anthony J.; Tromberg, Bruce J.; Frangioni, John V.

    2011-08-01

    Oxygenation measurements are widely used in patient care. However, most clinically available instruments currently consist of contact probes that only provide global monitoring of the patient (e.g., pulse oximetry probes) or local monitoring of small areas (e.g., spectroscopy-based probes). Visualization of oxygenation over large areas of tissue, without a priori knowledge of the location of defects, has the potential to improve patient management in many surgical and critical care applications. In this study, we present a clinically compatible multispectral spatial frequency domain imaging (SFDI) system optimized for surgical oxygenation imaging. This system was used to image tissue oxygenation over a large area (16×12 cm) and was validated during preclinical studies by comparing results obtained with an FDA-approved clinical oxygenation probe. Skin flap, bowel, and liver vascular occlusion experiments were performed on Yorkshire pigs and demonstrated that over the course of the experiment, relative changes in oxygen saturation measured using SFDI had an accuracy within 10% of those made using the FDA-approved device. Finally, the new SFDI system was translated to the clinic in a first-in-human pilot study that imaged skin flap oxygenation during reconstructive breast surgery. Overall, this study lays the foundation for clinical translation of endogenous contrast imaging using SFDI.

  1. Design of a visible-light spectroscopy clinical tissue oximeter.

    Science.gov (United States)

    Benaron, David A; Parachikov, Ilian H; Cheong, Wai-Fung; Friedland, Shai; Rubinsky, Boris E; Otten, David M; Liu, Frank W H; Levinson, Carl J; Murphy, Aileen L; Price, John W; Talmi, Yair; Weersing, James P; Duckworth, Joshua L; Hörchner, Uwe B; Kermit, Eben L

    2005-01-01

    We develop a clinical visible-light spectroscopy (VLS) tissue oximeter. Unlike currently approved near-infrared spectroscopy (NIRS) or pulse oximetry (SpO2%), VLS relies on locally absorbed, shallow-penetrating visible light (475 to 625 nm) for the monitoring of microvascular hemoglobin oxygen saturation (StO2%), allowing incorporation into therapeutic catheters and probes. A range of probes is developed, including noncontact wands, invasive catheters, and penetrating needles with injection ports. Data are collected from: 1. probes, standards, and reference solutions to optimize each component; 2. ex vivo hemoglobin solutions analyzed for StO2% and pO2 during deoxygenation; and 3. human subject skin and mucosal tissue surfaces. Results show that differential VLS allows extraction of features and minimization of scattering effects, in vitro VLS oximetry reproduces the expected sigmoid hemoglobin binding curve, and in vivo VLS spectroscopy of human tissue allows for real-time monitoring (e.g., gastrointestinal mucosal saturation 69+/-4%, n=804; gastrointestinal tumor saturation 45+/-23%, n=14; and p<0.0001), with reproducible values and small standard deviations (SDs) in normal tissues. FDA approved VLS systems began shipping earlier this year. We conclude that VLS is suitable for the real-time collection of spectroscopic and oximetric data from human tissues, and that a VLS oximeter has application to the monitoring of localized subsurface hemoglobin oxygen saturation in the microvascular tissue spaces of human subjects.

  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. 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...

  4. Heavy metals bioaccumulation in selected tissues of red swamp crayfish: An easy tool for monitoring environmental contamination levels.

    Science.gov (United States)

    Goretti, E; Pallottini, M; Ricciarini, M I; Selvaggi, R; Cappelletti, D

    2016-07-15

    In this paper we explored the heavy metal bioaccumulation (Cd, Cu, Pb and Zn) in Procambarus clarkii, a crayfish recently suggested as a potential bioindicator for metals pollution in freshwater systems. The present study is focused on crayfishes populations caught in a heavily polluted industrial and in a reference sites (Central Italy), though the results are generalized with a thorough analysis of literature metadata. In agreement with the literature, the hepatopancreas (Hep, detoxification tissues) of the red swamp crayfish showed a higher concentration of heavy metals in comparison to the abdominal muscle (AbM, not detoxification tissues) in the sites under scrutiny. Hep/AbM concentration ratio was dependent on the specific metal investigated and on its sediment contamination level. Specifically we found that Hep/AbM ratio decreases as follows: Cd (11.7)>Cu (5.5)>Pb (3.6)>Zn (1.0) and Pb (4.34)>Cd (3.66)>Zn (1.69)>Cu (0.87) for the industrial and reference sites, respectively. The analysis of our bioaccumulation data as well as of literature metadata allowed to elaborate a specific contamination index (Toxic Contamination Index, TCI), dependent only on the bioaccumulation data of hepatopancreas and abdominal muscle. In the industrial site, TCI expressed values much higher than the unit for Cd and Cu, confirming that these metals were the main contaminants; in contrast for lower levels of heavy metals, as those observed in the reference site for Cu, Zn and Pb, the index provided values below unit. TCI is proposed as a useful and easy tool to assess the toxicity level of contaminated sites by heavy metals in the environmental management. Copyright © 2016. Published by Elsevier B.V.

  5. Oxygen tension regulates the miRNA profile and bioactivity of exosomes released from extravillous trophoblast cells - Liquid biopsies for monitoring complications of pregnancy.

    Directory of Open Access Journals (Sweden)

    Grace Truong

    Full Text Available Our understanding of how cells communicate has undergone a paradigm shift since the recent recognition of the role of exosomes in intercellular signaling. In this study, we investigated whether oxygen tension alters the exosome release and miRNA profile from extravillous trophoblast (EVT cells, modifying their bioactivity on endothelial cells (EC. Furthermore, we have established the exosomal miRNA profile at early gestation in women who develop pre-eclampsia (PE and spontaneous preterm birth (SPTB. HTR-8/SVneo cells were used as an EVT model. The effect of oxygen tension (i.e. 8% and 1% oxygen on exosome release was quantified using nanocrystals (Qdot® coupled to CD63 by fluorescence NTA. A real-time, live-cell imaging system (Incucyte™ was used to establish the effect of exosomes on EC. Plasma samples were obtained at early gestation (<18 weeks and classified according to pregnancy outcomes. An Illumina TrueSeq Small RNA kit was used to construct a small RNA library from exosomal RNA obtained from EVT and plasma samples. The number of exosomes was significantly higher in EVT cultured under 1% compared to 8% oxygen. In total, 741 miRNA were identified in exosomes from EVT. Bioinformatic analysis revealed that these miRNA were associated with cell migration and cytokine production. Interestingly, exosomes isolated from EVT cultured at 8% oxygen increased EC migration, whilst exosomes cultured at 1% oxygen decreased EC migration. These changes were inversely proportional to TNF-α released from EC. Finally, we have identified a set of unique miRNAs in exosomes from EVT cultured at 1% oxygen and exosomes isolated from the circulation of mothers at early gestation, who later developed PE and SPTB. We suggest that aberrant exosomal signalling by placental cells is a common aetiological factor in pregnancy complications characterised by incomplete SpA remodeling and is therefore a clinically relevant biomarker of pregnancy complications.

  6. Injectable LiNc-BuO loaded microspheres as in vivo EPR oxygen sensors after co-implantation with tumor cells.

    Science.gov (United States)

    Frank, Juliane; Gündel, Daniel; Drescher, Simon; Thews, Oliver; Mäder, Karsten

    2015-12-01

    Electron paramagnetic resonance (EPR) oximetry is a technique which allows accurate and repeatable oxygen measurements. We encapsulated a highly oxygen sensitive particulate EPR spin probe into microparticles to improve its dispersibility and, hence, facilitate the administration. These biocompatible, non-toxic microspheres contained 5-10 % (w/w) spin probe and had an oxygen sensitivity of 0.60 ± 0.01 µT/mmHg. To evaluate the performance of the microparticles as oxygen sensors, they were co-implanted with syngeneic tumor cells in 2 different rat strains. Thus, tissue injury was avoided and the microparticles were distributed all over the tumor tissue. Dynamic changes of the intratumoral oxygen partial pressure during inhalation of 8 %, 21 %, or 100 % oxygen were monitored in vivo by EPR spectroscopy and quantified. Values were verified in vivo by invasive fluorometric measurements using Oxylite probes and ex vivo by pimonidazole adduct accumulation. There were no hints that the tumor physiology or tissue oxygenation had been altered by the microparticles. Hence, these microprobes offer great potential as oxygen sensors in preclinical research, not only for EPR spectroscopy but also for EPR imaging. For instance, the assessment of tissue oxygenation during therapeutic interventions might help understanding pathophysiological processes and lead to an individualized treatment planning or the use of formulations with hypoxia triggered release of active agents. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Tumor markers cancer antigen 15.3, carcinoembryonic antigen, and tissue polypeptide antigen for monitoring metastatic breast cancer during first-line chemotherapy and follow-up

    DEFF Research Database (Denmark)

    Sölétormos, G; Nielsen, D; Schiøler, V

    1996-01-01

    progressive disease, the median positive lead time was 35 days during therapy and 76 days during follow-up. Tumor marker assessment may document that a therapy is effective and ought to be continued in spite of adverse toxic effects, and that a treatment is ineffective and should be stopped to prevent......We investigated whether model systems integrating stochastic variation into criteria for marker assessment could be used for monitoring metastatic breast cancer. A total of 3989 serum samples was obtained from 204 patients receiving first-line chemotherapy and from 112 of these patients during...... follow-up. Each sample was analyzed for cancer antigen 15.3, carcinoembryonic antigen, and tissue polypeptide antigen. The efficiency for identifying progression and nonprogression was 94% during therapy and 85% during follow-up, with no false-positive marker results for progressive disease. At clinical...

  8. Autopsy tissues as biological monitors of human exposure to environmental pollutants. A case study: Concentrations of metals and PCDD/Fs in subjects living near a hazardous waste incinerator.

    Science.gov (United States)

    Domingo, José L; García, Francisco; Nadal, Martí; Schuhmacher, Marta

    2017-04-01

    Human biomonitoring is of tremendous importance to prevent potential adverse effects derived from human exposure to chemicals. Blood and urine are among the biological monitors more frequently used. However, biological matrices such as breast milk, hair, nails, saliva, feces, teeth, and expired air are also often used. In addition, and focused mainly on long-term exposure, adipose tissue and other human tissues like bone, liver, brain or kidney, are also used as biological monitors of certain substances, especially for long-term biomonitoring. However, for this kind of tissues sampling is always a limiting factor. In this paper, we have examined the role of autopsy tissues as biological monitors of human exposure to environmental pollutants. For it, we have used a case study conducted near a hazardous waste incinerator (HWI) in Catalonia (Spain), in which the concentrations of metals and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), have been periodically determined in autopsy tissues of subjects living in the area under potential influence of the facility. This case study does not show advantages -in comparison to other appropriate biomonitors such as blood- in using autopsy tissues in the monitoring of long-term exposure to metals and PCDD/Fs. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Real-time determination of intracellular oxygen in bacteria using a genetically encoded FRET-based biosensor

    Directory of Open Access Journals (Sweden)

    Potzkei Janko

    2012-03-01

    Full Text Available Abstract Background Molecular oxygen (O2 is one of the key metabolites of all obligate and facultative aerobic pro- and eukaryotes. It plays a fundamental role in energy homeostasis whereas oxygen deprivation, in turn, broadly affects various physiological and pathophysiological processes. Therefore, real-time monitoring of cellular oxygen levels is basically a prerequisite for the analysis of hypoxia-induced processes in living cells and tissues. Results We developed a genetically encoded Förster resonance energy transfer (FRET-based biosensor allowing the observation of changing molecular oxygen concentrations inside living cells. This biosensor named FluBO (fluorescent protein-based biosensor for oxygen consists of the yellow fluorescent protein (YFP that is sensitive towards oxygen depletion and the hypoxia-tolerant flavin-binding fluorescent protein (FbFP. Since O2 is essential for the formation of the YFP chromophore, efficient FRET from the FbFP donor domain to the YFP acceptor domain only occurs in the presence but not in the absence of oxygen. The oxygen biosensor was used for continuous real-time monitoring of temporal changes of O2 levels in the cytoplasm of Escherichia coli cells during batch cultivation. Conclusions FluBO represents a unique FRET-based oxygen biosensor which allows the non-invasive ratiometric readout of cellular oxygen. Thus, FluBO can serve as a novel and powerful probe for investigating the occurrence of hypoxia and its effects on a variety of (pathophysiological processes in living cells.

  10. Dynamic mechanisms of cardiac oxygenation during brief ischemia and reperfusion

    International Nuclear Information System (INIS)

    Parsons, W.J.; Rembert, J.C.; Bauman, R.P.; Greenfield, J.C. Jr.; Piantadosi, C.A.

    1990-01-01

    Myocardial oxygenation may be altered markedly by changes in tissue blood flow. During brief ischemia and reperfusion produced by transient occlusion of the left anterior descending artery in 10 open-chest dogs, changes in the oxygenation of tissue hemoglobin (Hb) plus myoglobin (Mb) and the oxidation-reduction (redox) state of mitochondrial cytochrome aa3 were monitored continuously using near-infrared spectroscopy. The nondestructive optical technique indicated that coronary occlusion produced an abrupt drop in tissue oxygen stores (tHb02 + Mb02), tissue blood volume (tBV), and the oxidation level of cytochrome aa3. Changes in the cytochrome oxidation state were related inversely to transmural collateral blood flow within the ischemic region (r = 0.77) measured with radiolabeled microspheres. Furthermore, there was a direct relationship (r = 0.91) between collateral blood flow and the tissue level of desaturated Hb and Mb (tHb + Mb). Reperfusion after 2 min of ischemia led to a synchronous overshoot of baseline in coronary flow and tBV followed by supranormal increases in tHb + Mb02 and the oxidation level of cytochrome aa3. The tHb + Mb level increased transiently during reperfusion. This response correlated inversely with collateral flow during ischemia (r = 0.91). Accordingly, the time required to reach peak tHb + Mb levels was shortest in dogs with high collateral flows (r = 0.75). Thus collateral blood flow partially sustains myocardial oxygenation during coronary artery occlusion and influences tissue reoxygenation early during reperfusion

  11. In Situ Resource Utilization (ISRU) on the Moon: Moessbauer Spectroscopy as a Process Monitor for Oxygen Production. Results from a Field Test on Mauna Kea Volcano, Hawaii

    Science.gov (United States)

    Morris, R.V.; Schroder, C.; Graff, T.G.; Sanders, G.B.; Lee, K.A.; Simon, T.M.; Larson, W.E.; Quinn, J.W.; Clark, L.D.; Caruso, J.J.

    2009-01-01

    Essential consumables like oxygen must to be produced from materials on the lunar surface to enable a sustained, long-term presence of humans on the Moon. The Outpost Precursor for ISRU and Modular Architecture (OPTIMA) field test on Mauna Kea, Hawaii, facilitated by the Pacific International Space Center for Exploration Systems (PISCES) of the University of Hawaii at Hilo, was designed to test the implementation of three hardware concepts to extract oxygen from the lunar regolith: Precursor ISRU Lunar Oxygen Testbed (PILOT) developed by Lockheed Martin in Littleton, CO; Regolith & Environmental Science and Oxygen & Lunar Volatiles Extraction (RESOLVE) developed at the NASA Kennedy Space Center in Cape Canaveral, FL; and ROxygen developed at the NASA Johnson Space Center in Houston, TX. The three concepts differ in design, but all rely on the same general principle: hydrogen reduction of metal cations (primarily Fe2+) bonded to oxygen to metal (e.g., Fe0) with the production of water. The hydrogen source is residual hydrogen in the fuel tanks of lunar landers. Electrolysis of the water produces oxygen and hydrogen (which is recycled). We used the miniaturized M ssbauer spectrometer MIMOS II to quantify the yield of this process on the basis of the quantity of Fe0 produced. Iron M ssbauer spectroscopy identifies iron-bearing phases, determines iron oxidation states, and quantifies the distribution of iron between mineral phases and oxidation states. The oxygen yield can be calculated by quantitative measurements of the distribution of Fe among oxidation states in the regolith before and after hydrogen reduction. A M ssbauer spectrometer can also be used as a prospecting tool to select the optimum feedstock for the oxygen production plants (e.g., high total Fe content and easily reduced phases). As a demonstration, a MIMOS II backscatter spectrometer (SPESI, Germany) was mounted on the Cratos rover (NASA Glenn Research Center in Cleveland, OH), which is one of

  12. Highly roughened polycaprolactone surfaces using oxygen plasma-etching and in vitro mineralization for bone tissue regeneration: fabrication, characterization, and cellular activities.

    Science.gov (United States)

    Kim, YongBok; Kim, GeunHyung

    2015-01-01

    Herein, poly(ɛ-caprolactone) (PCL) surfaces were treated to form various roughness values (R(a)=290-445 nm) and polar functional groups on the surfaces using a plasma-etching process, followed by immersion into simulated body fluid (SBF) for apatite formation. The surface morphology, chemical composition, and mean roughness of the plasma-etched PCL surfaces were measured, and various physical and morphological properties (water contact angles, protein absorption ability, and crystallite size of the apatite layer) of the in vitro mineralized PCL surfaces were evaluated. The roughened PCL surface P-3, which was treated with a sufficient plasma exposure time (4 h), achieved homogeneously distributed apatite formation after soaking in SBF for 7 days, as compared with other surfaces that were untreated or plasma-treated for 30 min or 2 h. Furthermore, to demonstrate their feasibility as a biomimetic surface, pre-osteoblast cells (MC3T3-E1) were cultured on the mineralized PCL surfaces, and cell viability, DAPI-phalloidin fluorescence assay, and alizarin red-staining of the P-3 surface were highly improved compared to the P-1 surface treated with a 30-min plasma exposure time; compared to untreated mineralized PCL surface (N-P), P-3 showed even greater improvements in cell viability and DAPI-phalloidin fluorescence assay. Based on these results, we found that the mineralized PCL surface supplemented with the appropriate plasma treatment can be implicitly helpful to achieve rapid hard tissue regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Short-term vitamin E treatment impairs reactive oxygen species signaling required for adipose tissue expansion, resulting in fatty liver and insulin resistance in obese mice.

    Directory of Open Access Journals (Sweden)

    Martin Alcala

    Full Text Available The use of antioxidant therapy in the treatment of oxidative stress-related diseases such as cardiovascular disease, diabetes or obesity remains controversial. Our aim is to demonstrate that antioxidant supplementation may promote negative effects if used before the establishment of oxidative stress due to a reduced ROS generation under physiological levels, in a mice model of obesity.C57BL/6J mice were fed with a high-fat diet for 14 weeks, with (OE group or without (O group vitamin E supplementation.O mice developed a mild degree of obesity, which was not enough to induce metabolic alterations or oxidative stress. These animals exhibited a healthy expansion of retroperitoneal white adipose tissue (rpWAT and the liver showed no signs of lipotoxicity. Interestingly, despite achieving a similar body weight, OE mice were insulin resistant. In the rpWAT they presented a reduced generation of ROS, even below physiological levels (C: 1651.0 ± 212.0; O: 3113 ± 284.7; OE: 917.6 ±104.4 RFU/mg protein. C vs OE p< 0.01. ROS decay may impair their action as second messengers, which could account for the reduced adipocyte differentiation, lipid transport and adipogenesis compared to the O group. Together, these processes limited the expansion of this fat pad and as a consequence, lipid flux shifted towards the liver, causing steatosis and hepatomegaly, which may contribute to the marked insulin resistance.This study provides in vivo evidence for the role of ROS as second messengers in adipogenesis, lipid metabolism and insulin signaling. Reducing ROS generation below physiological levels when the oxidative process has not yet been established may be the cause of the controversial results obtained by antioxidant therapy.

  14. Functional magnetic resonance imaging (fMRI) for fetal oxygenation during maternal hypoxia: initial results

    International Nuclear Information System (INIS)

    Wedegaertner, U.; Adam, G.; Tchirikov, M.; Schroeder, H.; Koch, M.

    2002-01-01

    Purpose: To investigate the potential of fMRI to measure changes in fetal tissue oxygenation during acute maternal hypoxia in fetal lambs. Material and Methods: Two ewes carrying singleton fetuses (gestational age 125 and 131 days) underwent MR imaging under inhalation anesthesia. BOLD imaging of the fetal brain, liver and myocardium was performed during acute maternal hypoxia (oxygen replaced by N 2 O). Maternal oxygen saturation and heart rate were monitored by a pulse-oxymeter attached to the maternal tongue. Results: Changes of fetal tissue oxygenation during maternal hypoxia were clearly visible with BOLD MRI. Signal intensity decreases were more distinct in liver and heart (∝40%) from control than in the fetal brain (∝10%). Conclusions: fMRI is a promising diagnostic tool to determine fetal tissue oxygenation and may open new opportunities in monitoring fetal well being in high risk pregnancies complicated by uteroplacentar insufficiency. Different signal changes in liver/heart and brain may reflect a centralization of the fetal blood flow. (orig.) [de

  15. Phenobarbital and neonatal seizures affect cerebral oxygen metabolism: a near-infrared spectroscopy study.

    Science.gov (United States)

    Sokoloff, Max D; Plegue, Melissa A; Chervin, Ronald D; Barks, John D E; Shellhaas, Renée A

    2015-07-01

    Near-infrared spectroscopy (NIRS) measures oxygen metabolism and is increasingly used for monitoring critically ill neonates. The implications of NIRS-recorded data in this population are poorly understood. We evaluated NIRS monitoring for neonates with seizures. In neonates monitored with video-electroencephalography, NIRS-measured cerebral regional oxygen saturation (rSO2) and systemic O2 saturation were recorded every 5 s. Mean rSO2 was extracted for 1-h blocks before, during, and after phenobarbital doses. For each electrographic seizure, mean rSO2 was extracted for a period of three times the duration of the seizure before and after the ictal pattern, as well as during the seizure. Linear mixed models were developed to assess the impact of phenobarbital administration and of seizures on rSO2 and fractional tissue oxygen extraction. For 20 neonates (estimated gestational age: 39.6 ± 1.5 wk), 61 phenobarbital doses and 40 seizures were analyzed. Cerebral rSO2 rose (P = 0.005), and fractional tissue oxygen extraction declined (P = 0.018) with increasing phenobarbital doses. rSO2 declined during seizures, compared with baseline and postictal phases (baseline 81.2 vs. ictal 77.7 vs. postictal 79.4; P = 0.004). Fractional tissue oxygen extraction was highest during seizures (P = 0.002). Cerebral oxygen metabolism decreases after phenobarbital administration and increases during seizures. These small, but clear, changes in cerebral oxygen metabolism merit assessment for potential clinical impact.

  16. Monitoring Tumor Response to Carbogen Breathing by Oxygen-Sensitive Magnetic Resonance Parameters to Predict the Outcome of Radiation Therapy: A Preclinical Study

    Energy Technology Data Exchange (ETDEWEB)

    Cao-Pham, Thanh-Trang; Tran, Ly-Binh-An; Colliez, Florence; Joudiou, Nicolas [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium); El Bachiri, Sabrina [Université Catholique de Louvain, IMMAQ Technological Platform, Methodology and Statistical Support, Louvain-la-Neuve (Belgium); Grégoire, Vincent [Université Catholique de Louvain, Institute of Experimental and Clinical Research, Center for Molecular Imaging, Radiotherapy and Oncology, Brussels (Belgium); Levêque, Philippe; Gallez, Bernard [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium); Jordan, Bénédicte F., E-mail: benedicte.jordan@uclouvain.be [Université Catholique de Louvain, Louvain Drug Research Institute, Biomedical Magnetic Resonance Research Group, Brussels (Belgium)

    2016-09-01

    Purpose: In an effort to develop noninvasive in vivo methods for mapping tumor oxygenation, magnetic resonance (MR)-derived parameters are being considered, including global R{sub 1}, water R{sub 1}, lipids R{sub 1}, and R{sub 2}*. R{sub 1} is sensitive to dissolved molecular oxygen, whereas R{sub 2}* is sensitive to blood oxygenation, detecting changes in dHb. This work compares global R{sub 1}, water R{sub 1}, lipids R{sub 1}, and R{sub 2}* with pO{sub 2} assessed by electron paramagnetic resonance (EPR) oximetry, as potential markers of the outcome of radiation therapy (RT). Methods and Materials: R{sub 1}, R{sub 2}*, and EPR were performed on rhabdomyosarcoma and 9L-glioma tumor models, under air and carbogen breathing conditions (95% O{sub 2}, 5% CO{sub 2}). Because the models demonstrated different radiosensitivity properties toward carbogen, a growth delay (GD) assay was performed on the rhabdomyosarcoma model and a tumor control dose 50% (TCD50) was performed on the 9L-glioma model. Results: Magnetic resonance imaging oxygen-sensitive parameters detected the positive changes in oxygenation induced by carbogen within tumors. No consistent correlation was seen throughout the study between MR parameters and pO{sub 2}. Global and lipids R{sub 1} were found to be correlated to pO{sub 2} in the rhabdomyosarcoma model, whereas R{sub 2}* was found to be inversely correlated to pO{sub 2} in the 9L-glioma model (P=.05 and .03). Carbogen increased the TCD50 of 9L-glioma but did not increase the GD of rhabdomyosarcoma. Only R{sub 2}* was predictive (P<.05) for the curability of 9L-glioma at 40 Gy, a dose that showed a difference in response to RT between carbogen and air-breathing groups. {sup 18}F-FAZA positron emission tomography imaging has been shown to be a predictive marker under the same conditions. Conclusion: This work illustrates the sensitivity of oxygen-sensitive R{sub 1} and R{sub 2}* parameters to changes in tumor oxygenation. However, R{sub 1

  17. Monitoring Tumor Response to Carbogen Breathing by Oxygen-Sensitive Magnetic Resonance Parameters to Predict the Outcome of Radiation Therapy: A Preclinical Study

    International Nuclear Information System (INIS)

    Cao-Pham, Thanh-Trang; Tran, Ly-Binh-An; Colliez, Florence; Joudiou, Nicolas; El Bachiri, Sabrina; Grégoire, Vincent; Levêque, Philippe; Gallez, Bernard; Jordan, Bénédicte F.

    2016-01-01

    Purpose: In an effort to develop noninvasive in vivo methods for mapping tumor oxygenation, magnetic resonance (MR)-derived parameters are being considered, including global R_1, water R_1, lipids R_1, and R_2*. R_1 is sensitive to dissolved molecular oxygen, whereas R_2* is sensitive to blood oxygenation, detecting changes in dHb. This work compares global R_1, water R_1, lipids R_1, and R_2* with pO_2 assessed by electron paramagnetic resonance (EPR) oximetry, as potential markers of the outcome of radiation therapy (RT). Methods and Materials: R_1, R_2*, and EPR were performed on rhabdomyosarcoma and 9L-glioma tumor models, under air and carbogen breathing conditions (95% O_2, 5% CO_2). Because the models demonstrated different radiosensitivity properties toward carbogen, a growth delay (GD) assay was performed on the rhabdomyosarcoma model and a tumor control dose 50% (TCD50) was performed on the 9L-glioma model. Results: Magnetic resonance imaging oxygen-sensitive parameters detected the positive changes in oxygenation induced by carbogen within tumors. No consistent correlation was seen throughout the study between MR parameters and pO_2. Global and lipids R_1 were found to be correlated to pO_2 in the rhabdomyosarcoma model, whereas R_2* was found to be inversely correlated to pO_2 in the 9L-glioma model (P=.05 and .03). Carbogen increased the TCD50 of 9L-glioma but did not increase the GD of rhabdomyosarcoma. Only R_2* was predictive (P<.05) for the curability of 9L-glioma at 40 Gy, a dose that showed a difference in response to RT between carbogen and air-breathing groups. "1"8F-FAZA positron emission tomography imaging has been shown to be a predictive marker under the same conditions. Conclusion: This work illustrates the sensitivity of oxygen-sensitive R_1 and R_2* parameters to changes in tumor oxygenation. However, R_1 parameters showed limitations in terms of predicting the outcome of RT in the tumor models studied, whereas R_2* was found to be

  18. Dissolved Oxygen Sensor in Animal-Borne Instruments: An Innovation for Monitoring the Health of Oceans and Investigating the Functioning of Marine Ecosystems.

    Science.gov (United States)

    Bailleul, Frederic; Vacquie-Garcia, Jade; Guinet, Christophe

    2015-01-01

    The current decline in dissolved oxygen concentration within the oceans is a sensitive indicator of the effect of climate change on marine environment. However the impact of its declining on marine life and ecosystems' health is still quite unclear because of the difficulty in obtaining in situ data, especially in remote areas, like the Southern Ocean (SO). Southern elephant seals (Mirounga leonina) proved to be a relevant alternative to the traditional oceanographic platforms to measure physical and biogeochemical structure of oceanic regions rarely observed. In this study, we use a new stage of development in biologging technology to draw a picture of dissolved oxygen concentration in the SO. We present the first results obtained from a dissolved oxygen sensor added to Argos CTD-SRDL tags and deployed on 5 female elephant seals at Kerguelen. From October 2010 and October 2011, 742 oxygen profiles associated with temperature and salinity measurements were recorded. Whether a part of the data must be considered cautiously, especially because of offsets and temporal drifts of the sensors, the range of values recorded was consistent with a concomitant survey conducted from a research vessel (Keops-2 project). Once again, elephant seals reinforced the relationship between marine ecology and oceanography, delivering essential information about the water masses properties and the biological status of the Southern Ocean.