Root Effect Haemoglobins in Fish May Greatly Enhance General Oxygen Delivery Relative to Other Vertebrates.

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Jodie L Rummer

Full Text Available The teleost fishes represent over half of all extant vertebrates; they occupy nearly every body of water and in doing so, occupy a diverse array of environmental conditions. We propose that their success is related to a unique oxygen (O2 transport system involving their extremely pH-sensitive haemoglobin (Hb. A reduction in pH reduces both Hb-O2 affinity (Bohr effect and carrying capacity (Root effect. This, combined with a large arterial-venous pH change (ΔpHa-v relative to other vertebrates, may greatly enhance tissue oxygen delivery in teleosts (e.g., rainbow trout during stress, beyond that in mammals (e.g., human. We generated oxygen equilibrium curves (OECs at five different CO2 tensions for rainbow trout and determined that, when Hb-O2 saturation is 50% or greater, the change in oxygen partial pressure (ΔPO2 associated with ΔpHa-v can exceed that of the mammalian Bohr effect by at least 3-fold, but as much as 21-fold. Using known ΔpHa-v and assuming a constant arterial-venous PO2 difference (Pa-vO2, Root effect Hbs can enhance O2 release to the tissues by 73.5% in trout; whereas, the Bohr effect alone is responsible for enhancing O2 release by only 1.3% in humans. Disequilibrium states are likely operational in teleosts in vivo, and therefore the ΔpHa-v, and thus enhancement of O2 delivery, could be even larger. Modeling with known Pa-vO2 in fish during exercise and hypoxia indicates that O2 release from the Hb and therefore potentially tissue O2 delivery may double during exercise and triple during some levels of hypoxia. These characteristics may be central to performance of athletic fish species such as salmonids, but may indicate that general tissue oxygen delivery may have been the incipient function of Root effect Hbs in fish, a trait strongly associated with the adaptive radiation of teleosts.

Relationship Between Cerebral Oxygenation and Hemodynamic and Oxygen Transport Parameters in Surgery for Acquired Heart Diseases

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A. I. Lenkin

2012-01-01

Full Text Available Objective: to evaluate the relationship between cerebral oxygenation and hemodynamic and oxygen transport parameters in surgical correction of concomitant acquired heart diseases. Subjects and methods. Informed consent was received from 40 patients who required surgery because of concomitant (two or more acquired heart defects. During procedure, perioperative monitoring of oxygen transport and cerebral oxygenation was performed with the aid of PiCCO2 monitor (Pulsion Medical Systems, Germany and a Fore-Sight cerebral oximeter (CASMED, USA. Anesthesia was maintained with propofol and fen-tanyl, by monitoring the depth of anesthesia. Early postoperative intensive therapy was based on the protocol for early targeted correction of hemodynamic disorders. Oxygen transport and cerebral oxygenation parameters were estimated intraopera-tively and within 24 postoperative hours. A statistical analysis including evaluation of Spearman correlations was performed with the aid of SPSS 15.0. Results. During perfusion, there was a relationship between cerebral oximetry values and hemat-ocrit levels, and oxygen partial pressure in the venous blood. Furthermore, a negative correlation between cerebral oximetry values and blood lactate levels was found 30 minutes after initiation of extracorporeal circulation (EC. During the study, there was a positive correlation between cerebral oxygenation and values of cardiac index, central venous saturation, and oxygen delivery index. There was a negative relationship between cerebral oxygenation and extravascular lung water at the beginning of surgery and a correlation between cerebral oximetry values and oxygenation index by the end of the first 24 postoperative hours. Conclusion. The cerebral oxygenation values correlate -with the main determinants of oxygen transport during EC and after cardiac surgical procedures. Cerebral oximetry may be used in early targeted therapy for the surgical correction of acquired combined

Proposal of a service delivery integration index of home care for older persons: application in several European cities

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Jean-Claude Henrard

2006-07-01

Full Text Available Purpose: To propose an integration index of home care delivery to older persons, to study its validity and to apply it to home care services of European cities. Theory: Home care delivery integration was based on two dimensions referring to process-centred integration and organisational structure approach. Method: Items considered as part of both dimensions according to an expert consensus (face validity were extracted from a standardised questionnaire used in “Aged in Home care” (AdHoc study to capture basic characteristics of home care services. Their summation leads to a services' delivery integration index. This index was applied to AdHoc services. A factor analysis was computed in order to empirically test the validity of the theoretical constructs. The plot of the settings was performed. Results: Application of the index ranks home care services in four groups according to their score. Factor analysis identifies a first factor which opposes working arrangement within service to organisational structure bringing together provisions for social care. A second factor corresponds to basic nursing care and therapies. Internal consistency for those three domains ranges from 0.78 to 0.93. When plotting the different settings different models of service delivery appear. Conclusion: The proposed index shows that behind a total score several models of care delivery are hidden. Comparison of service delivery integration should take into account this heterogeneity.

Leg oxygen uptake in the initial phase of intense exercise is slowed by a marked reduction in oxygen delivery

DEFF Research Database (Denmark)

Christensen, Peter Møller; Nyberg, Michael Permin; Mortensen, Stefan Peter

2013-01-01

-extensor exercise (60±3 W) for 4 min in a control setting (CON) and with arterial infusion of L-NMMA and indomethacin in the working leg to reduce blood flow by inhibiting formation of nitric oxide and prostanoids (double blockade; DB). In DB leg blood flow (LBF) and oxygen delivery during the first minute...

Oxygen saturation index and severity of hypoxic respiratory failure.

Science.gov (United States)

Rawat, Munmun; Chandrasekharan, Praveen K; Williams, Ashley; Gugino, Sylvia; Koenigsknecht, Carmon; Swartz, Daniel; Ma, Chang Xing; Mathew, Bobby; Nair, Jayasree; Lakshminrusimha, Satyan

2015-01-01

The oxygenation index (OI = mean airway pressure, MAP × FiO2 × 100 : PaO2) is used to assess the severity of hypoxic respiratory failure (HRF) and persistent pulmonary hypertension of the newborn (PPHN). An indwelling arterial line or arterial punctures are necessary to obtain PaO2 for the calculation of OI. Oxygenation can be continuously and noninvasively assessed using pulse oximetry. The use of the oxygen saturation index (OSI = MAP × FiO2 × 100 : SpO2) can be an alternate method of assessing the severity of HRF. To evaluate the correlation between OSI and OI in the following: (1) neonates with HRF and (2) a lamb model of meconium aspiration syndrome. Human neonates: a retrospective chart review of 74 ventilated late preterm/term neonates with indwelling arterial access and SpO2 values in the first 24 h of life was conducted. OSI and OI were calculated and correlated. Lamb model: arterial blood gases were drawn and preductal SpO2 was documented in 40 term newborn lambs with asphyxia and meconium aspiration. OI and OSI were calculated and correlated with pulmonary vascular resistance (PVR). Mean values of OSI and OI showed a correlation coefficient of 0.952 in neonates (mean value of 308 observations in 74 neonates) and 0.948 in lambs (mean value of 743 observations in 40 lambs). In lambs, with increasing PVR, there was a decrease in OI and OSI. OSI correlates significantly with OI in infants with HRF. This noninvasive measure may be used to assess the severity of HRF and PPHN in neonates without arterial access. © 2015 S. Karger AG, Basel

Localized increase of tissue oxygen tension by magnetic targeted drug delivery

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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

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

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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

Closed Loop Control of Oxygen Delivery and Oxygen Generation

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2017-08-01

were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

Acute oxygen therapy: a review of prescribing and delivery practices

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Cousins JL

2016-05-01

Full Text Available Joyce L Cousins,1–3 Peter AB Wark,3–5 Vanessa M McDonald2–5 1Faculty of Arts, Nursing and Theology, Avondale College of Higher Education, Sydney, 2School of Nursing and Midwifery, 3Priority Research Centre for Healthy Lungs, 4School of Medicine and Public Health, The University of Newcastle, 5Department of Respiratory and Sleep Medicine, Hunter Medical Research Institute, John Hunter Hospital, Newcastle, NSW, Australia Abstract: Oxygen is a commonly used drug in the clinical setting and like other drugs its use must be considered carefully. This is particularly true for those patients who are at risk of type II respiratory failure in whom the risk of hypercapnia is well established. In recent times, several international bodies have advocated for the prescription of oxygen therapy in an attempt to reduce this risk in vulnerable patient groups. Despite this guidance, published data have demonstrated that there has been poor uptake of these recommendations. Multiple interventions have been tested to improve concordance, and while some of these interventions show promise, the sustainability of these interventions are less convincing. In this review, we summarize data that have been published on the prevalence of oxygen prescription and the accurate and appropriate administration of this drug therapy. We also identify strategies that have shown promise in facilitating changes to oxygen prescription and delivery practice. There is a clear need to investigate the barriers, facilitators, and attitudes of clinicians in relation to the prescription of oxygen therapy in acute care. Interventions based on these findings then need to be designed and tested to facilitate the application of evidence-based guidelines to support sustained changes in practice, and ultimately improve patient care. Keywords: chronic obstructive pulmonary disease, COPD, type II respiratory failure, oxygen therapy, prescribing, hypoxia, hypercapnia

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

OpenAIRE

Fan, J.-L.

2014-01-01

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

Limited oxygen index levels of impregnated Scots pine wood

International Nuclear Information System (INIS)

Tomak, Eylem Dizman; Cavdar, Ayfer Donmez

2013-01-01

Highlights: • Scots pine samples were treated with 4 wood preservatives with various concentrations. • Limited oxygen index level was evaluated both for leached and un-leached samples. • All treatments improved fire retardance of samples despite some chemicals leached out. • Samples treated with fireproof agent showed the best results. • LOI of samples treated with boron powder and silicon oil was not changed by leaching. - Abstract: In this study, effect of various concentrations of boron powder, mixture of boric acid and borax, fireproof agent based on liquid blend of limestone, and silicon oil on limited oxygen index levels (LOI) of S. pine wood was investigated. Wood samples were first vacuum treated with the preservatives, and then were subjected to leaching procedure. Samples treated with fireproof agent showed the best results for improving the fire retardancy of wood, furthermore, samples treated with 25%, 50% and 100% of the solution did not burn. Leaching did not considerably change the LOI of wood samples treated with boron powder and silicon oil; however, LOI levels of samples treated with the mixture of boric acid and borax and fireproof agent were affected by leaching procedure probably arising those preservatives did not chemically bond to main wood components. All treatments improved fire retardancy of samples despite some amount of preservatives leached out from wood

Limited oxygen index levels of impregnated Scots pine wood

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Tomak, Eylem Dizman, E-mail: eylemdizman@yahoo.com [Forest Industry Engineering Department, Faculty of Forestry, Bursa Technical University, 16200 Bursa (Turkey); Cavdar, Ayfer Donmez [Interior Architecture Department, Faculty of Architecture, Karadeniz Technical University, 61080 Trabzon (Turkey)

2013-12-10

Highlights: • Scots pine samples were treated with 4 wood preservatives with various concentrations. • Limited oxygen index level was evaluated both for leached and un-leached samples. • All treatments improved fire retardance of samples despite some chemicals leached out. • Samples treated with fireproof agent showed the best results. • LOI of samples treated with boron powder and silicon oil was not changed by leaching. - Abstract: In this study, effect of various concentrations of boron powder, mixture of boric acid and borax, fireproof agent based on liquid blend of limestone, and silicon oil on limited oxygen index levels (LOI) of S. pine wood was investigated. Wood samples were first vacuum treated with the preservatives, and then were subjected to leaching procedure. Samples treated with fireproof agent showed the best results for improving the fire retardancy of wood, furthermore, samples treated with 25%, 50% and 100% of the solution did not burn. Leaching did not considerably change the LOI of wood samples treated with boron powder and silicon oil; however, LOI levels of samples treated with the mixture of boric acid and borax and fireproof agent were affected by leaching procedure probably arising those preservatives did not chemically bond to main wood components. All treatments improved fire retardancy of samples despite some amount of preservatives leached out from wood.

Model analysis of local oxygen delivery with liposome-encapsulated hemoglobin.

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Matsumoto, Takeshi; Mano, Katsuhiko; Ueha, Ryohei; Naito, Hisashi; Tanaka, Masao

2009-03-01

Liposome-encapsulated hemoglobins (LHs) are comparable to red blood cells (RBCs) in terms of oxygen (O(2))-carrying capacity. The smaller particle size of LHs than of platelets allows their homogeneous dispersion in circulating plasma. In this study, we evaluated the effect of LH transfusion on arterial O(2) delivery through vascular trees by simulation. A mathematical model was established on the basis of the coronary arterial anatomy, the conservation of flow and RBC flux, and Poiseuille's law. The Fåhraeus-Lindqvist, Fåhraeus, and phase separation effects were considered in the model. By assuming steady perfusion, the arterial flow and O(2) delivery were calculated for five model trees undergoing the isovolumic replacement of RBCs (0.3 mg hemoglobin (Hb)/mL) with LHs (0.2 mg Hb/mL) or a plasma volume expander (PVE). The RBC-LH exchange increased both the total flow and the total O(2) flux but had almost no effect on the relative distribution of O(2) flux. In contrast, the RBC-PVE exchange decreased the total O(2) flux and increased the proportion of regions receiving a relatively low O(2) supply. Thus, LH transfusion may compensate for an enhanced bias in RBC-associated O(2) flux under hemodilution and is expected to be beneficial for both total and local O(2) delivery.

ESTIMATION OF INDUSTRIAL WASTE SAFETY BY THE “CHEMICAL OXYGEN DEMAND” INDEX

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A. S. Kayshev

2015-01-01

Full Text Available One of the indices of industrial waste safety including distillers grains is chemical oxygen demand (COD, and its value (53591÷64184 mg O/dm3 shows that it can be considered as unsustainable waste. This high value of COD is conditioned by the absence of toxins in distillers grains, and by concentration of biologically active substances after which isolation the distillers grains index lowers by 74%. This allows considering the distillers grains as environmentally safe. The results received evidence the necessity for consideration of COD index only as an index of oxidized substances, but not the criteria of waste pollution.

Adsorption of oxygen on low-index surfaces of the TiAl{sub 3} alloy

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Latyshev, A. M.; Bakulin, A. V.; Kulkova, S. E., E-mail: kulkova@ms.tsc.ru [National Research Tomsk State University (Russian Federation); Hu, Q. M.; Yang, R. [Chinese Academy of Sciences, Shenyang National Laboratory for Materials Science, Institute of Metal Research (China)

2016-12-15

Method of the projector augmented waves in the plane-wave basis within the generalized-gradient approximation for the exchange-correlation functional has been used to study oxygen adsorption on (001), (100), and (110) low-index surfaces of the TiAl{sub 3} alloy. It has been established that the sites that are most energetically preferred for the adsorption of oxygen are hollow (H) positions on the (001) surface and bridge (B) positions on the (110) and (100) surfaces. Structural and electronic factors that define their energy preference have been discussed. Changes in the atomic and electronic structure of subsurface layers that occur as the oxygen concentration increases to three monolayers have been analyzed. It has been shown that the formation of chemical bonds of oxygen with both components of the alloy leads to the appearance of states that are split-off from the bottoms of their valence bands, which is accompanied by the formation of a forbidden gap at the Fermi level and by a weakening of the Ti–Al metallic bonds in the alloy. On the Al-terminated (001) and (110) surfaces, the oxidation of aluminum dominates over that of titanium. On the whole, the binding energy of oxygen on the low-index surfaces with a mixed termination is higher than that at the aluminum-terminated surface. The calculation of the diffusion of oxygen in the TiAl{sub 3} alloy has shown that the lowest barriers correspond to the diffusion between tetrahedral positions in the (001) plane; the diffusion of oxygen in the [001] direction occurs through octahedral and tetrahedral positions. An increase in the concentration of aluminum in the alloy favors a reduction in the height of the energy barriers as compared to the corresponding barriers in the γ-TiAl alloy.

Inner Retinal Oxygen Delivery, Metabolism, and Extraction Fraction in Ins2Akita Diabetic Mice.

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Blair, Norman P; Wanek, Justin; Felder, Anthony E; Brewer, Katherine C; Joslin, Charlotte E; Shahidi, Mahnaz

2016-11-01

Retinal nonperfusion and hypoxia are important factors in human diabetic retinopathy, and these presumably inhibit energy production and lead to cell death. The purpose of this study was to elucidate the effect of diabetes on inner retinal oxygen delivery and metabolism in a mouse model of diabetes. Phosphorescence lifetime and blood flow imaging were performed in spontaneously diabetic Ins2Akita (n = 22) and nondiabetic (n = 22) mice at 12 and 24 weeks of age to measure retinal arterial (O2A) and venous (O2V) oxygen contents and total retinal blood flow (F). Inner retinal oxygen delivery (DO2) and metabolism (MO2) were calculated as F ∗ O2A and F ∗ (O2A - O2V), respectively. Oxygen extraction fraction (OEF), which equals MO2/DO2, was calculated. DO2 at 12 weeks were 112 ± 40 and 97 ± 29 nL O2/min in nondiabetic and diabetic mice, respectively (NS), and 148 ± 31 and 85 ± 37 nL O2/min at 24 weeks, respectively (P < 0.001). MO2 were 65 ± 31 and 66 ± 27 nL O2/min in nondiabetic and diabetic mice at 12 weeks, respectively, and 79 ± 14 and 54 ± 28 nL O2/min at 24 weeks, respectively (main effects = NS). At 12 weeks OEF were 0.57 ± 0.17 and 0.67 ± 0.09 in nondiabetic and diabetic mice, respectively, and 0.54 ± 0.07 and 0.63 ± 0.08 at 24 weeks, respectively (main effect of diabetes: P < 0.01). Inner retinal MO2 was maintained in diabetic Akita mice indicating that elevation of the OEF adequately compensated for reduced DO2 and prevented oxidative metabolism from being limited by hypoxia.

Proposal of a service delivery integration index of home care for older persons: application in several European cities.

NARCIS (Netherlands)

Henrard, J.C.; Ankri, J.; Frijters, D.; Carpenter, I.; Topinkova, E.; Garms-Homolova, V.; Finne-Soveri, H.; Wergeland Sorbye, L.; Jonsson, P.V.; Ljunggren, G.; Schroll, M.; Wagner, C.; Bernabei, R.

2006-01-01

PURPOSE: To propose an integration index of home care delivery to older persons, to study its validity and to apply it to home care services of European cities. THEORY: Home care delivery integration was based on two dimensions referring to process-centred integration and organisational structure

Cardiopulmonary function and oxygen delivery during total liquid ventilation.

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Tsagogiorgas, Charalambos; Alb, Markus; Herrmann, Peter; Quintel, Michael; Meinhardt, Juergen P

2011-10-01

Total liquid ventilation (TLV) with perfluorocarbons has shown to improve cardiopulmonary function in the injured and immature lung; however there remains controversy over the normal lung. Hemodynamic effects of TLV in the normal lung currently remain undetermined. This study compared changes in cardiopulmonary and circulatory function caused by either liquid or gas tidal volume ventilation. In a prospective, controlled study, 12 non-injured anesthetized, adult New Zealand rabbits were primarily conventionally gas-ventilated (CGV). After instrumentation for continuous recording of arterial (AP), central venous (CVP), left artrial (LAP), pulmonary arterial pressures (PAP), and cardiac output (CO) animals were randomized into (1) CGV group and (2) TLV group. In the TLV group partial liquid ventilation was initiated with instillation of perfluoroctylbromide (12 ml/kg). After 15 min, TLV was established for 3 hr applying a volume-controlled, pressure-limited, time-cycled ventilation mode using a double-piston configured TLV. Controls (CGV) remained gas-ventilated throughout the experiment. During TLV, heart rate, CO, PAP, MAP, CVP, and LAP as well as derived hemodynamic variables, arterial and mixed venous blood gases, oxygen delivery, PVR, and SVR did not differ significantly compared to CGV. Liquid tidal volumes suitable for long-term TLV in non-injured rabbits do not significantly impair CO, blood pressure, and oxygen dynamics when compared to CGV. Copyright © 2011 Wiley-Liss, Inc.

Retinal Oxygen Delivery and Metabolism in Healthy and Sickle Cell Retinopathy Subjects.

Science.gov (United States)

Shahidi, Mahnaz; Felder, Anthony E; Tan, Ou; Blair, Norman P; Huang, David

2018-04-01

Reduction in inner retinal oxygen delivery (DO2) can cause retinal hypoxia and impair inner retinal oxygen metabolism (MO2), leading to vision loss. The purpose of the current study was to establish measurements of DO2 and MO2 in healthy subjects and test the hypothesis that DO2 and MO2 are reduced in sickle cell retinopathy (SCR) subjects. Dual wavelength retinal oximetry and Doppler optical coherence tomography were performed in 12 healthy control and 12 SCR subjects. Images were analyzed to measure retinal arterial and venous oxygen content (O2A and O2V), venous diameter (DV), and total retinal blood flow (TRBF). Retinal arteriovenous oxygen content difference (O2AV), DO2, MO2, and oxygen extraction fraction (OEF) were calculated according to the following equations: O2AV = O2A - O2V; DO2 = TRBF * O2A; MO2 = TRBF * O2AV; OEF = MO2/DO2. Retinal DV and TRBF were higher in the SCR group as compared to the control group, whereas, O2A, O2V, and O2AV were lower in SCR group as compared to the control group. DO2, MO2, and OEF were not significantly different between control and SCR groups. MO2 and DO2 were linearly related, such that higher MO2 was associated with higher DO2. There was an inverse relationship between TRBF and OEF, such that lower TRBF was associated with higher OEF. Increased blood flow compensated for decreased oxygen content, thereby maintaining DO2, MO2, and OEF at predominately lower stages of SCR. Quantitative assessment of these parameters has the potential to advance knowledge and improve diagnostic evaluation of retinal ischemic conditions.

Development and Validation of an Index to Measure the Quality of Facility-Based Labor and Delivery Care Processes in Sub-Saharan Africa.

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Vandana Tripathi

Full Text Available High quality care is crucial in ensuring that women and newborns receive interventions that may prevent and treat birth-related complications. As facility deliveries increase in developing countries, there are concerns about service quality. Observation is the gold standard for clinical quality assessment, but existing observation-based measures of obstetric quality of care are lengthy and difficult to administer. There is a lack of consensus on quality indicators for routine intrapartum and immediate postpartum care, including essential newborn care. This study identified key dimensions of the quality of the process of intrapartum and immediate postpartum care (QoPIIPC in facility deliveries and developed a quality assessment measure representing these dimensions.Global maternal and neonatal care experts identified key dimensions of QoPIIPC through a modified Delphi process. Experts also rated indicators of these dimensions from a comprehensive delivery observation checklist used in quality surveys in sub-Saharan African countries. Potential QoPIIPC indices were developed from combinations of highly-rated indicators. Face, content, and criterion validation of these indices was conducted using data from observations of 1,145 deliveries in Kenya, Madagascar, and Tanzania (including Zanzibar. A best-performing index was selected, composed of 20 indicators of intrapartum/immediate postpartum care, including essential newborn care. This index represented most dimensions of QoPIIPC and effectively discriminated between poorly and well-performed deliveries.As facility deliveries increase and the global community pays greater attention to the role of care quality in achieving further maternal and newborn mortality reduction, the QoPIIPC index may be a valuable measure. This index complements and addresses gaps in currently used quality assessment tools. Further evaluation of index usability and reliability is needed. The availability of a streamlined

Minimally invasive prediction of ScvO2 in high-risk surgery : The introduction of a model Index of Oxygenation

NARCIS (Netherlands)

de Grooth, Harm-Jan S.; Vos, Jaap Jan; Scheeren, Thomas; van Beest, Paul

2014-01-01

INTRODUCTION: The purpose of this study was to examine the trilateral relationship between cardiac index (CI), tissue oxygen saturation (StO2) and central venous oxygen saturation (ScvO2) and subsequently develop a model to predict ScvO2 on minimal invasive manner in patients undergoing major

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

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Amy G. Tsai

2014-10-01

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

Indications for primary cesarean delivery relative to body mass index

Science.gov (United States)

Kawakita, Tetsuya; Reddy, Uma M.; Landy, Helain J.; Iqbal, Sara N.; Huang, Chun-Chih; Grantz, Katherine L.

2016-01-01

Background Obesity is a known risk factor for cesarean delivery. Limited data are available regarding the reasons for the increased rate of primary cesarean in obese women. It is important to identify the factors leading to an increased risk of cesarean to identify opportunities to reduce the primary cesarean rate. Objective We evaluated indications for primary cesarean across body mass index kg/m2 classes to identify the factors contributing to the increase rate of cesarean among obese women. Study design In the Consortium of Safe Labor study between 2002 and 2008, we calculated indications for primary cesarean including failure to progress or cephalopelvic disproportion, non-reassuring fetal heart tracing, malpresentation, elective, hypertensive disease, multiple gestation, placenta previa or vasa previa, failed induction, human immunodeficiency virus or active herpes simplex virus, history of uterine scar, fetal indication, placental abruption, chorioamnionitis, macrosomia, and failed operative delivery. For women with primary cesarean for failure to progress or cephalopelvic disproportion, dilation at the last recorded cervical examination was evaluated. Women were categorized according to body mass index on admission: normal weight (18.5-24.9), overweight (25.0-29.9), obese class I (30.0-34.9), II (35.0-39.9), and III (≥40). Cochran-Armitage Trend Test and Chi-square tests were performed. Results Of 66,502 nulliparous and 76,961 multiparous women in the study population, 19,431 nulliparous (29.2%) and 7,329 multiparous women (9.5%) underwent primary cesarean. Regardless of parity, malpresentation, failure to progress or cephalopelvic disproportion, and non-reassuring fetal heart tracing were the common indications for primary cesarean. Regardless of parity, the rates of primary cesarean for failure to progress or cephalopelvic disproportion increased with increasing body mass index (normal weight, class I, II and III obesity in nulliparous: 33.2%, 41.6%, 46

Interdelivery weight gain and risk of cesarean delivery following a prior vaginal delivery.

Science.gov (United States)

Dude, Annie M; Lane-Cordova, Abbi D; Grobman, William A

2017-09-01

Approximately one third of all deliveries in the United States are via cesarean. Previous research indicates weight gain during pregnancy is associated with an increased risk of cesarean delivery. It remains unclear, however, whether and to what degree weight gain between deliveries (ie, interdelivery weight gain) is associated with cesarean delivery in a subsequent pregnancy following a vaginal delivery. The objective of the study was to determine whether interdelivery weight gain is associated with an increased risk of intrapartum cesarean delivery following a vaginal delivery. This was a case-control study of women who had 2 consecutive singleton births of at least 36 weeks' gestation between 2005 and 2016, with a vaginal delivery in the index pregnancy. Women were excluded if they had a contraindication to a trial of labor (eg, fetal malpresentation or placenta previa) in the subsequent pregnancy. Maternal characteristics and delivery outcomes for both pregnancies were abstracted from the medical record. Maternal weight gain between deliveries was measured as the change in body mass index at delivery. Women who underwent a subsequent cesarean delivery were compared with those who had a repeat vaginal delivery using χ 2 statistics for categorical variables and Student t tests or analysis of variance for continuous variables. Multivariable logistic regression was used to determine whether interdelivery weight gain remained independently associated with intrapartum cesarean delivery after adjusting for potential confounders. Of 10,396 women who met eligibility criteria and had complete data, 218 (2.1%) had a cesarean delivery in the subsequent pregnancy. Interdelivery weight gain was significantly associated with cesarean delivery and remained significant in multivariable analysis for women with a body mass index increase of at least 2 kg/m 2 (adjusted odds ratio, 1.53, 95% confidence interval, 1.03-2.27 for a body mass index increase of 2 kg/m 2 to gained 2 kg

Numerical Modeling of Limiting Oxygen Index Apparatus for Film Type Fuels

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Amit Kumar

2012-12-01

Full Text Available A detailed three-dimensional numerical model is used to compute the flow pattern and the flame behavior of thin solid fuels in a rectangular column that resembles a standard Limiting Oxygen Index (LOI device. The model includes full Navier-Stokes equations for mixed buoyant-forced flow and finite rate combustion and pyrolysis reactions so that the sample LOI can be computed to study the effect of feeding flow rate, sample width and gravity levels. In addition to the above parameters, the sample location in the column and the column cross-sectional area are also investigated on their effect on the ambient air entrainment from the top.

Innovation in Evaluating the Impact of Integrated Service-Delivery: The Integra Indexes of HIV and Reproductive Health Integration.

Science.gov (United States)

Mayhew, Susannah H; Ploubidis, George B; Sloggett, Andy; Church, Kathryn; Obure, Carol D; Birdthistle, Isolde; Sweeney, Sedona; Warren, Charlotte E; Watts, Charlotte; Vassall, Anna

2016-01-01

The body of knowledge on evaluating complex interventions for integrated healthcare lacks both common definitions of 'integrated service delivery' and standard measures of impact. Using multiple data sources in combination with statistical modelling the aim of this study is to develop a measure of HIV-reproductive health (HIV-RH) service integration that can be used to assess the degree of service integration, and the degree to which integration may have health benefits to clients, or reduce service costs. Data were drawn from the Integra Initiative's client flow (8,263 clients in Swaziland and 25,539 in Kenya) and costing tools implemented between 2008-2012 in 40 clinics providing RH services in Kenya and Swaziland. We used latent variable measurement models to derive dimensions of HIV-RH integration using these data, which quantified the extent and type of integration between HIV and RH services in Kenya and Swaziland. The modelling produced two clear and uncorrelated dimensions of integration at facility level leading to the development of two sub-indexes: a Structural Integration Index (integrated physical and human resource infrastructure) and a Functional Integration Index (integrated delivery of services to clients). The findings highlight the importance of multi-dimensional assessments of integration, suggesting that structural integration is not sufficient to achieve the integrated delivery of care to clients--i.e. "functional integration". These Indexes are an important methodological contribution for evaluating complex multi-service interventions. They help address the need to broaden traditional evaluations of integrated HIV-RH care through the incorporation of a functional integration measure, to avoid misleading conclusions on its 'impact' on health outcomes. This is particularly important for decision-makers seeking to promote integration in resource constrained environments.

Innovation in Evaluating the Impact of Integrated Service-Delivery: The Integra Indexes of HIV and Reproductive Health Integration.

Directory of Open Access Journals (Sweden)

Susannah H Mayhew

Full Text Available The body of knowledge on evaluating complex interventions for integrated healthcare lacks both common definitions of 'integrated service delivery' and standard measures of impact. Using multiple data sources in combination with statistical modelling the aim of this study is to develop a measure of HIV-reproductive health (HIV-RH service integration that can be used to assess the degree of service integration, and the degree to which integration may have health benefits to clients, or reduce service costs.Data were drawn from the Integra Initiative's client flow (8,263 clients in Swaziland and 25,539 in Kenya and costing tools implemented between 2008-2012 in 40 clinics providing RH services in Kenya and Swaziland. We used latent variable measurement models to derive dimensions of HIV-RH integration using these data, which quantified the extent and type of integration between HIV and RH services in Kenya and Swaziland. The modelling produced two clear and uncorrelated dimensions of integration at facility level leading to the development of two sub-indexes: a Structural Integration Index (integrated physical and human resource infrastructure and a Functional Integration Index (integrated delivery of services to clients. The findings highlight the importance of multi-dimensional assessments of integration, suggesting that structural integration is not sufficient to achieve the integrated delivery of care to clients--i.e. "functional integration".These Indexes are an important methodological contribution for evaluating complex multi-service interventions. They help address the need to broaden traditional evaluations of integrated HIV-RH care through the incorporation of a functional integration measure, to avoid misleading conclusions on its 'impact' on health outcomes. This is particularly important for decision-makers seeking to promote integration in resource constrained environments.

Determining the Source of Water Vapor in a Cerium Oxide Electrochemical Oxygen Separator to Achieve Aviator Grade Oxygen

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Graf, John; Taylor, Dale; Martinez, James

2014-01-01

]. Combined with a mechanical compressor, a Solid Electrolyte Oxygen Separator (SEOS) should be capable of producing ABO grade oxygen at pressures >2400 psia, on the space station. Feasibility tests using a SEOS integrated with a mechanical compressor identified an unexpected contaminant in the oxygen: water vapour was found in the oxygen product, sometimes at concentrations higher than 40 ppm (the ABO limit for water vapour is 7 ppm). If solid electrolyte membranes are really "infinitely selective" to oxygen as they are reported to be, where did the water come from? If water is getting into the oxygen, what other contaminants might get into the oxygen? Microscopic analyses of wafers, welds, and oxygen delivery tubes were performed in an attempt to find the source of the water vapour contamination. Hot and cold pressure decay tests were performed. Measurements of water vapour as a function of O2 delivery rate, O2 delivery pressure, and process air humidity levels were the most instructive in finding the source of water contamination (Fig 3). Water contamination was directly affected by oxygen delivery rate (doubling the oxygen production rate cut the water level in half). Water was affected by process air humidity levels and delivery pressure in a way that indicates the water was diffusing into the oxygen delivery system.

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

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

2018-06-01

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

The impact of an hematocrit of 20% during normothermic cardiopulmonary bypass for elective low risk coronary artery bypass graft surgery on oxygen delivery and clinical outcome – a randomized controlled study [ISRCTN35655335

Science.gov (United States)

von Heymann, Christian; Sander, Michael; Foer, Achim; Heinemann, Anja; Spiess, Bruce; Braun, Jan; Krämer, Michael; Grosse, Joachim; Dohmen, Pascal; Dushe, Simon; Halle, Jürgen; Konertz, Wolfgang F; Wernecke, Klaus-Dieter; Spies, Claudia

2006-01-01

Introduction Cardiopulmonary bypass (CPB) induces hemodilutional anemia, which frequently requires the transfusion of blood products. The objective of this study was to evaluate oxygen delivery and consumption and clinical outcome in low risk patients who were allocated to an hematocrit (Hct) of 20% versus 25% during normothermic CPB for elective coronary artery bypass graft (CABG) surgery. Methods This study was a prospective, randomized and controlled trial. Patients were subjected to normothermic CPB (35 to 36°C) and were observed until discharge from the intensive care unit (ICU). Outcome measures were calculated whole body oxygen delivery, oxygen consumption and clinical outcome. A nonparametric multivariate analysis of variance for repeated measurements and small sample sizes was performed. Results In a total of 54 patients (25% Hct, n = 28; 20% Hct, n = 26), calculated oxygen delivery (p = 0.11), oxygen consumption (p = 0.06) and blood lactate (p = 0.60) were not significantly different between groups. Clinical outcomes were not different between groups. Conclusion These data indicate that an Hct of 20% during normothermic CPB maintained calculated whole body oxygen delivery above a critical level after elective CABG surgery in low risk patients. The question of whether a transfusion trigger in excess of 20% Hct during normothermic CPB is still supported requires a larger prospective and randomized trial. PMID:16606474

Uniform distributions of glucose oxidation and oxygen extraction in gray matter of normal human brain: No evidence of regional differences of aerobic glycolysis.

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Hyder, Fahmeed; Herman, Peter; Bailey, Christopher J; Møller, Arne; Globinsky, Ronen; Fulbright, Robert K; Rothman, Douglas L; Gjedde, Albert

2016-05-01

Regionally variable rates of aerobic glycolysis in brain networks identified by resting-state functional magnetic resonance imaging (R-fMRI) imply regionally variable adenosine triphosphate (ATP) regeneration. When regional glucose utilization is not matched to oxygen delivery, affected regions have correspondingly variable rates of ATP and lactate production. We tested the extent to which aerobic glycolysis and oxidative phosphorylation power R-fMRI networks by measuring quantitative differences between the oxygen to glucose index (OGI) and the oxygen extraction fraction (OEF) as measured by positron emission tomography (PET) in normal human brain (resting awake, eyes closed). Regionally uniform and correlated OEF and OGI estimates prevailed, with network values that matched the gray matter means, regardless of size, location, and origin. The spatial agreement between oxygen delivery (OEF≈0.4) and glucose oxidation (OGI ≈ 5.3) suggests that no specific regions have preferentially high aerobic glycolysis and low oxidative phosphorylation rates, with globally optimal maximum ATP turnover rates (VATP ≈ 9.4 µmol/g/min), in good agreement with (31)P and (13)C magnetic resonance spectroscopy measurements. These results imply that the intrinsic network activity in healthy human brain powers the entire gray matter with ubiquitously high rates of glucose oxidation. Reports of departures from normal brain-wide homogeny of oxygen extraction fraction and oxygen to glucose index may be due to normalization artefacts from relative PET measurements. © The Author(s) 2016.

Gamma-index method sensitivity for gauging plan delivery accuracy of volumetric modulated arc therapy.

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Park, Jong In; Park, Jong Min; Kim, Jung-In; Park, So-Yeon; Ye, Sung-Joon

2015-12-01

The aim of this study was to investigate the sensitivity of the gamma-index method according to various gamma criteria for volumetric modulated arc therapy (VMAT). Twenty head and neck (HN) and twenty prostate VMAT plans were retrospectively selected for this study. Both global and local 2D gamma evaluations were performed with criteria of 3%/3 mm, 2%/2 mm, 1%/2 mm and 2%/1 mm. In this study, the global and local gamma-index calculated the differences in doses relative to the maximum dose and the dose at the current measurement point, respectively. Using log files acquired during delivery, the differences in parameters at every control point between the VMAT plans and the log files were acquired. The differences in dose-volumetric parameters between reconstructed VMAT plans using the log files and the original VMAT plans were calculated. The Spearman's rank correlation coefficients (rs) were calculated between the passing rates and those differences. Considerable correlations with statistical significances were observed between global 1%/2 mm, local 1%/2 mm and local 2%/1 mm and the MLC position differences (rs = -0.712, -0.628 and -0.581). The numbers of rs values with statistical significance between the passing rates and the changes in dose-volumetric parameters were largest in global 2%/2 mm (n = 16), global 2%/1 mm (n = 15) and local 2%/1 mm (n = 13) criteria. Local gamma-index method with 2%/1 mm generally showed higher sensitivity to detect deviations between a VMAT plan and the delivery of the VMAT plan. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Study on the effect of hyperbaric oxygen therapy on the wound healing and the related serum indexes of rectal abscess patients after surgery

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Bo Mo, Qing He

2016-07-01

Full Text Available Objective: To observe and research the influence degree of hyperbaric oxygen therapy on wound healing and related serum indexes of rectal abscess patients after surgery. Methods: A total of 48 rectal abscess patients treated with operation in my hospital from April 2014 to August 2015 were taken as research objects, and the 48 patients were randomly divided into two groups: control group (postoperative routine treatments, 24 cases and observation group (postoperative routine treatments and hyperbaric oxygen therapy, 24 cases, and then compared the time constitutes of wound healing, the edema degrees and the related serum indexes of patients in two test groups before the operation and at 1 d, 3 d and 10 d after operation. Results: The time constitute of wound healing of observation group is better than that of control group, and the edema degree and the related serum index of observation group are lower than those of control group, and the test result of two groups have significant differences. Conclusions: The hyperbaric oxygenation therapy can effectively promote the postoperative wound healing of patients with rectal abscess, and it also has active clinical significance for the control of edema and related serum indexes.

Supplemental Oxygen in Elective Cesarean Section under Spinal Anesthesia: Handle the Sword with Care

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Saban Yalcin

2013-09-01

Full Text Available Background and objectives: : We aimed to investigate the effect of 21% and 40% oxygen supplementation on maternal and neonatal oxidative stress in elective cesarean section (CS under spinal anesthesia. Methods: Eighty term parturients undergoing elective CS under spinal anesthesia were enrolled in the study. We allocated patients randomly to breathe 21% (air group or 40% (oxygen group oxygen from the time of skin incision until the end of the operation. We collected maternal pre- and post-operative and umbilical artery (UA blood samples. Total antioxidant capacity (TAC, total oxidant status (TOS and the oxidative stress index (OSI were measured. Results: Age, weight, height, parity, gestation week, spinal-skin incision time, skin incision-delivery time, delivery time, operation time, 1st and 5th minutes Apgar scores, and birth weight were similar between the groups (p > 0.05 for all comparisons. There were no differences in preoperative TAC, TOS, or OSI levels between the groups (p > 0.05 for all comparisons. Postoperative maternal TAC, TOS and OSI levels significantly increased in the oxygen group (p = 0.047, < 0.001 and 0.038, respectively; umbilical artery TAC levels significantly increased in the oxygen group (p = 0.003; and umbilical artery TOS and OSI levels significantly increased in the air group (p = 0.02 and < 0.001, respectively. Conclusions: The difference in impact on maternal and fetal oxidative stress of supplemental 40% compared to 21% oxygen mandates further large-scale studies that investigate the role of oxygen supplementation during elective CS under spinal anesthesia. Keywords: Anesthesia, Spinal, Cesarean Section, Oxidative Stress, Oxygen, Oxygen Inhalation Therapy

Calculating Preference Weights for the Labor and Delivery Index: A Discrete Choice Experiment on Women’s Birth Experiences

NARCIS (Netherlands)

Gärtner, F.R.; Bekker-Grob, E.W. de; Stiggelbout, A.M.; Rijnders, M.E.; Freeman, L.M.; Middeldorp, J.M.; Bloemenkamp, K.W.; Miranda E. de; Akker-van Marle, M.E. van den

2015-01-01

Objective The aim of this study was to calculate preference weights for the Labor and Delivery Index (LADY-X) to make it suitable as a utility measure for perinatal care studies. Methods In an online discrete choice experiment, 18 pairs of hypothetical scenarios were presented to respondents, from

The effects of altitude/hypoxic training on oxygen delivery capacity of the blood and aerobic exercise capacity in elite athletes - a meta-analysis.

Science.gov (United States)

Park, Hun-Young; Hwang, Hyejung; Park, Jonghoon; Lee, Seongno; Lim, Kiwon

2016-03-31

This study was designed as a meta-analysis of randomized controlled trials comparing effectiveness of altitude/hypoxic training (experimental) versus sea-level training (control) on oxygen delivery capacity of the blood and aerobic exercise capacity of elite athletes in Korea. Databases (Research Information Service System, Korean studies Information Service System, National Assembly Library) were for randomized controlled trials comparing altitude/hypoxic training versus sea-level training in elite athletes. Studies published in Korea up to December 2015 were eligible for inclusion. Oxygen delivery capacity of the blood was quantified by red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), erythropoietin (EPO); and aerobic exercise capacity was quantified by maximal oxygen consumption (VO2max). RBC, Hb, Hct, VO2max represented heterogeneity and compared post-intervention between altitude/hypoxic training and sea-level training in elite athletes by a random effect model meta-analysis. EPO represented homogeneity and meta-analysis performed by a fixed effect model. Eight independent studies with 156 elite athletes (experimental: n = 82, control: n = 74) were included in the metaanalysis. RBC (4.499×10(5) cell/ul, 95 % CI: 2.469 to 6.529), Hb (5.447 g/dl, 95 % CI: 3.028 to 7.866), Hct (3.639 %, 95 % CI: 1.687 to 5.591), EPO (0.711 mU/mL, 95% CI: 0.282 to 1.140), VO2max (1.637 ml/kg/min, 95% CI: 0.599 to 1.400) showed significantly greater increase following altitude/hypoxic training, as compared with sea-level training. For elite athletes in Korea, altitude/ hypoxic training appears more effective than sea-level training for improvement of oxygen delivery capacity of the blood and aerobic exercise capacity.

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

International Nuclear Information System (INIS)

Hong, Sung-Ha; Jenkins, A Toby A; Szili, Endre J; Short, Robert D

2014-01-01

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine. (fast track communication)

Ionized gas (plasma) delivery of reactive oxygen species (ROS) into artificial cells

Science.gov (United States)

Hong, Sung-Ha; Szili, Endre J.; Jenkins, A. Toby A.; Short, Robert D.

2014-09-01

This study was designed to enhance our understanding of how reactive oxygen species (ROS), generated ex situ by ionized gas (plasma), can affect the regulation of signalling processes within cells. A model system, comprising of a suspension of phospholipid vesicles (cell mimics) encapsulating a ROS reporter, was developed to study the plasma delivery of ROS into cells. For the first time it was shown that plasma unequivocally delivers ROS into cells over a sustained period and without compromising cell membrane integrity. An important consideration in cell and biological assays is the presence of serum, which significantly reduced the transfer efficiency of ROS into the vesicles. These results are key to understanding how plasma treatments can be tailored for specific medical or biotechnology applications. Further, the phospholipid vesicle ROS reporter system may find use in other studies involving the application of free radicals in biology and medicine.

Tubing length for long-term oxygen therapy.

Science.gov (United States)

Aguiar, Carolina; Davidson, Josy; Carvalho, Andréa K; Iamonti, Vinícius C; Cortopassi, Felipe; Nascimento, Oliver A; Jardim, José R

2015-02-01

Most patients on long-term oxygen therapy use stationary oxygen delivery systems. It is not uncommon for guidelines to instruct patients to use tubing lengths no longer than 19.68 ft (6 m) when using an oxygen concentrator and 49.21 ft (15 m) when using cylinders. However, these concepts are not based on sufficient evidence. Thus, our objective was to evaluate whether a 98.42-ft (30-m) tubing length affects oxygen flow and FIO2 delivery from 1 cylinder and 2 oxygen concentrators. The 3 oxygen delivery systems were randomly selected, and 1, 3, and 5 L/min flows and FIO2 were measured 5 times at each flow at the proximal and distal outlets of the tubing by a gas-flow analyzer. Paired Student t test was used to analyze the difference between flows and FIO2 at proximal and distal outlets of tubing length. A total of 45 flows were measured between proximal and distal outlets of the 98.42-ft (30-m) tubing. Flows were similar for 1 and 3 L/min, but distal flow was higher than proximal flow at 5 L/min (5.57×5.14 L/min, Ptubing at flows 1, 3, and 5 L/min, but the mean difference between measurements was less than 1%. Tubing length of 98.42 ft (30 m) may be used by patients for home delivery oxygen with flows up to 5 L/min, as there were no important changes in flows or FIO2. Copyright © 2015 by Daedalus Enterprises.

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

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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.

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.

The effects of altitude/hypoxic training on oxygen delivery capacity of the blood and aerobic exercise capacity in elite athletes – a meta-analysis

Science.gov (United States)

Park, Hun-young; Hwang, Hyejung; Park, Jonghoon; Lee, Seongno; Lim, Kiwon

2016-01-01

[Purpose] This study was designed as a meta-analysis of randomized controlled trials comparing effectiveness of altitude/hypoxic training (experimental) versus sea-level training (control) on oxygen delivery capacity of the blood and aerobic exercise capacity of elite athletes in Korea. [Methods] Databases (Research Information Service System, Korean studies Information Service System, National Assembly Library) were for randomized controlled trials comparing altitude/hypoxic training versus sea-level training in elite athletes. Studies published in Korea up to December 2015 were eligible for inclusion. Oxygen delivery capacity of the blood was quantified by red blood cell (RBC), hemoglobin (Hb), hematocrit (Hct), erythropoietin (EPO); and aerobic exercise capacity was quantified by maximal oxygen consumption (VO2max). RBC, Hb, Hct, VO2max represented heterogeneity and compared post-intervention between altitude/hypoxic training and sea-level training in elite athletes by a random effect model meta-analysis. EPO represented homogeneity and meta-analysis performed by a fixed effect model. Eight independent studies with 156 elite athletes (experimental: n = 82, control: n = 74) were included in the metaanalysis. [Results] RBC (4.499×105 cell/ul, 95 % CI: 2.469 to 6.529), Hb (5.447 g/dl, 95 % CI: 3.028 to 7.866), Hct (3.639 %, 95 % CI: 1.687 to 5.591), EPO (0.711 mU/mL, 95% CI: 0.282 to 1.140), VO2max (1.637 ml/kg/min, 95% CI: 0.599 to 1.400) showed significantly greater increase following altitude/hypoxic training, as compared with sea-level training. [Conclusion] For elite athletes in Korea, altitude/ hypoxic training appears more effective than sea-level training for improvement of oxygen delivery capacity of the blood and aerobic exercise capacity. PMID:27298808

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

NARCIS (Netherlands)

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

2015-01-01

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

Postnatal follow-up of the oxygenation index, arterial to alveolar oxygen tension ratio and alveolar arterial oxygen tension difference values in neonates with the respiratory distress syndrome treated with conventional ventilatory support.

Science.gov (United States)

Atanasov, A; Despotova-Toleva, L

1997-01-01

Recent development of sophisticated intensive care technique for use in newborn infants with the respiratory distress syndrome (RDS) has resulted in changes in the therapeutic strategies and moved the problem of neonatal survival into the realm of new therapeutic realities. At present, the mechanical ventilation methods form an integral part of the intensive care strategy of infants with RDS. They have come to the forefront of infant care because of their successful use in ventilatory support and children survival where other therapeutic modalities have failed. The present prospective observational longitudinal study was designed to assess the real-time convenience, reliability and accuracy of the changes in the oxygenation index (OI), arterial-to-alveolar oxygen tension ratio (a/A PO2) and alveolar-arterial oxygen gradient (A-a)DO2 in ventilator-dependent neonates with RDS, to analyze their feasibility and potential information yield in oxygen inhalation therapy as well as their prognostic implications and predictive value. Twenty neonates with RDS, heralded by respiratory failure which necessitated the initiation of oxygen inhalation therapy and ventilatory support within 24 hours of birth, were enrolled in the study. Ten of the infants survived and the remaining ten died. OI, (a/A PO2) and (A-a)DO2 were followed up sequentially and thoroughly analyzed as the primary outcome measures of the study. The indices were calculated on the basis of the complete monitoring of the ventilatory equipment parameters and acid-base status carried out on an hourly basis. Our results show that: 1. The combination of three indexes (OI, (a/A)PO2 and (A-a)DO2 we propose is a useful discriminating predictor of neonatal lung maturity reflecting arterial blood gas status in ventilator-dependent neonates with RDS. 2. The indices detect the efficacy of the modern conventional ventilatory support with real-time convenience and reliable accuracy forming the cornerstone of clinical decision

Transvaginal cervical length and amniotic fluid index: can it predict delivery latency following preterm premature rupture of membranes?

Science.gov (United States)

Mehra, Suwan; Amon, Erol; Hopkins, Sarah; Gavard, Jeffrey A; Shyken, Jaye

2015-03-01

We sought to determine whether transvaginal cervical length (TVCL), amniotic fluid index (AFI), or a combination of both can predict delivery latency within 7 days in women presenting with preterm premature rupture of membranes (PPROM). This was a prospective observational study of TVCL measurements in 106 singleton pregnancies with PPROM between 23-33 weeks. Delivery latency was defined as the period (in days) from the initial TVCL after PPROM to delivery of the infant, with our primary outcome being delivery within 7 days of TVCL. The independent predictability of significant characteristics for delivery within 7 days was determined using multiple logistic regression. Sensitivity, specificity, and predictive values were used to examine whether the presence of a short TVCL, AFI, or a combination of both affected the risk of delivery within 7 days. Delivery within 7 days occurred in 51/106 (48%) of pregnancies. Median duration (interquartile range) from PPROM to delivery and TVCL to delivery was 8 days (4.0-16.0) and 8 days (3.0-15.0), respectively. Using multiple regression TVCL as a continuous variable (odds ratio, 0.65; 95% confidence interval, 0.44-0.97; P 7 days for TVCL >2 cm alone was 61%. This predictive value changed when analyzed in conjunction with an AFI ≤5 cm and >5 cm at 42% and 89%, respectively. A shorter TVCL and an AFI ≤5 cm independently predict delivery within 7 days in women presenting with PPROM. The combination of an AFI >5 cm and TVCL >2 cm greatly improved the potential to remain undelivered at 7 days following cervical length assessment. These findings may be helpful for counseling and optimizing maternal and neonatal care in women with PPROM. Copyright © 2015 Elsevier Inc. All rights reserved.

Bulk manufacture of concentrated oxygen gas-filled microparticles for intravenous oxygen delivery.

Science.gov (United States)

Kheir, John N; Polizzotti, Brian D; Thomson, Lindsay M; O'Connell, Daniel W; Black, Katherine J; Lee, Robert W; Wilking, James N; Graham, Adam C; Bell, David C; McGowan, Francis X

2013-08-01

Self-assembling, concentrated, lipid-based oxygen microparticles (LOMs) have been developed to administer oxygen gas when injected intravenously, preventing organ injury and death from systemic hypoxemia in animal models. Distinct from blood substitutes, LOMs are a one-way oxygen carrier designed to rescue patients who experience life-threatening hypoxemia, as caused by airway obstruction or severe lung injury. Here, we describe methods to manufacture large quantities of LOMs using an in-line, recycling, high-shear homogenizer, which can create up to 4 liters of microparticle emulsion in 10 minutes, with particles containing a median diameter of 0.93 microns and 60 volume% of gas phase. Using this process, we screen 30 combinations of commonly used excipients for their ability to form stable LOMs. LOMs composed of DSPC and cholesterol in a 1:1 molar ratio are stable for a 100 day observation period, and the number of particles exceeding 10 microns in diameter does not increase over time. When mixed with blood in vitro, LOMs fully oxygenate blood within 3.95 seconds of contact, and do not cause hemolysis or complement activation. LOMs can be manufactured in bulk by high shear homogenization, and appear to have a stability and size profile which merit further testing. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxygen therapy reduces postoperative tachycardia

DEFF Research Database (Denmark)

Stausholm, K; Kehlet, H; Rosenberg, J

1995-01-01

Concomitant hypoxaemia and tachycardia in the postoperative period is unfavourable for the myocardium. Since hypoxaemia per se may be involved in the pathogenesis of postoperative tachycardia, we have studied the effect of oxygen therapy on tachycardia in 12 patients randomly allocated to blinded...... air or oxygen by facemask on the second or third day after major surgery. Inclusion criteria were arterial hypoxaemia (oxygen saturation 90 beat.min-1). Each patient responded similarly to oxygen therapy: an increase in arterial oxygen saturation and a decrease...... in heart rate (p oxygen has a positive effect on the cardiac oxygen delivery and demand balance....

Comparison of actual oxygen delivery kinetics to those predicted by mathematical modeling following stage 1 palliation just prior to superior cavopulmonary anastomosis.

Science.gov (United States)

Yuki, Koichi; DiNardo, James A

2015-02-01

Optimizing systemic oxygen delivery (DO2) and hemodynamics in children with hypoplastic left heart syndrome (HLHS) is a clinical challenge. Mathematical modeling of the HLHS circulation has been used to determine the relationship between oxygen kinetic parameters and DO2 and to determine how DO2 might be optimized. The model demonstrates that neither arterial oxygen saturation (SaO2) nor mixed venous oxygen saturation (SvO2) alone accurately predicts DO2. Oxygen delivery kinetics predicted by previously described mathematical modeling were compared with actual patients' hemodynamic data. We sought to determine which patient derived parameters correlated best with DO2. Patients with HLHS who underwent cardiac catheterization prior to surgery to create a superior cavopulmonary anastomosis from 2007 to 2011 were identified. Hemodynamic data obtained were compared with the data derived from the mathematical model. Correlations between SaO2, SvO2, SaO2-SvO2, SaO2/(SaO2-SvO2), pulmonary-to-systemic blood flow ratio (Qp/Qs), and DO2 were evaluated using both linear and nonlinear analyses, and R(2) was calculated. Patients' data fit most aspects of the mathematical model. DO2 had the best correlation with SaO2/(SaO2-SvO2; R(2) = 0.8755) followed by SaO2 -SvO2 (R(2) = 0.8063), while SaO2 or SvO2 alone did not demonstrate a significant correlation as predicated by the mathematical model (R(2) = 0.09564 and 0.4831, respectively). SaO2/(SaO2 -SvO2) would be useful clinically to track changes in DO2 that occur with changes in patient condition or with interventions. © 2014 John Wiley & Sons Ltd.

[Domiciliary oxygen therapy].

Science.gov (United States)

Abdel Kafi, S

2010-09-01

In Belgium, oxygen therapy is becoming more and more accessible. When oxygen is needed for short periods or for special indications as palliative care, an agreement between mutual insurance companies and pharmacists allows the practitioner the home installation of gazeous oxygen cylinder or of oxygen concentrator. When long term oxygen therapy (LTOT) is indicated for patients with respiratory insufficiency, the pneumologist must first ask the INAMI the authorization to install one of the following modalities: oxygen concentrator with or without demand oxygen delivery cylinder and liquid oxygen. The goal of LTOT is to increase survival and quality of life. The principal and well accepted indication for LTOT is severe hypoxemia. The beneficial effects of oxygen therapy limited at night or on exertion are controversial. In order to increase patient's autonomy, oxygen can be prescribed for ambulation, respecting prescription's rules. At each step of oxygen therapy implementing (indication, choice of the device and follow-up) the patient under oxygen may benefit from a joint approach between the general practitioner and the chest specialist.

Complex Evaluation Oxygen Status and Lipid Metabolism Indexes in Newborns with Perinatal Hypoxia and Hypovolemic Shock

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Svetlana A. Perepelitsa

2017-01-01

Full Text Available Aim. To asses of metabolism, lipid metabolism and oxygen status parameters in newborns with perinatal hypoxia.Materials and Methods. 53 newborn babies born with signs of severe hypoxia and low Apgar scoring equal to 2 at the 1st minute of life were enrolled in the study. Newborns were divided into 2 groups depending on the presence of the clinical presentation of shock: Group 1 «Shock» and Group 2 «Acute intranatal hypoxia» (AIH. All newborns underwent testing for blood gas and acid-base balance, lactate level. Cholesterol and triglyceride levels in the central venous blood were also tested immediately after the birth and on the 5th day of life. Mechanical ventilation mode and parameters were registered. The mean airway pressure (MAP and the oxygen saturation index (OSI were calculated.Results. Severe decompensated metabolic lactic acidosis was diagnosed in a «Shock» group newborns at birth, thus indicating severe perinatal hypoxia which had triggered the development of shock. As for the «AIH» group newborns, they had hyperlactatemia alone. The most severe hypoxemia at birth was diagnosed in newborns of the «Shock» group; the OSI value in these infants was significantly higher than that in «AIH» infants (P<0.01. Despite the treatment and mechanical ventilation, during the posthypoxic period, newborns from the «Shock» group were characterized by increased OSI values over 12 hours after birth. Significantly high levels of OSI persisted for 48 hours after the delivery. Severe hypotriglyceridemia and hypocholesterolemia were found in both group newborns.Conclusion. The study demonstrated that there was intranatal complex metabolism impairment in the case of perinatal hypoxia; at birth, it manifested by metabolic acidosis of various degrees of severity and imbalance of triglycerides and cholesterol levels. The longer and more severe hypoxia is, the more severe acid-base balance and blood lactate level impairment at birth become

Longitudinal Changes in Physical Activity Level, Body Mass Index, and Oxygen Uptake Among Norwegian Adolescents

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Pål Lagestad

2018-03-01

Full Text Available Several studies have investigated activity levels among adolescents, but no study has examined longitudinal changes in physical activity (PA level, body mass, and oxygen uptake among the same adolescents from the age of 14 to 19 years. The present study examined data from a research project that included a group of randomly selected students (N = 116 with objective measurements of PA (accelerometer data, self-reported PA level, and body mass and oxygen uptake during a 5-year period. The results show a significant decrease in the accelerometer-based PA level over time, from age 14 to 19. At 14 years of age, the minutes of moderate and/or vigorous PA was 66.7 min·day−1, but was less than half, at only 24.4 min·day−1, at 19 years of age. The self-reported activity data show a decrease in girls’ general activity level over time, while boys’ activity level during school breaks decreased strongly during the period: at age 14, 61% of the boys were classified as active, while at age 19, only 11% were physically active. Furthermore, body mass index increased during the period for both genders, while oxygen uptake decreased. Since both BMI and maximal oxygen uptake are important risk factors for future CVD, these findings point toward the importance of maintaining a high activity level during childhood and adolescence, in order to keep fit later in life.

Osmotic phenomena in application for hyperbaric oxygen treatment.

Science.gov (United States)

Babchin, A; Levich, E; Melamed M D, Y; Sivashinsky, G

2011-03-01

Hyperbaric oxygen (HBO) treatment defines the medical procedure when the patient inhales pure oxygen at elevated pressure conditions. Many diseases and all injuries are associated with a lack of oxygen in tissues, known as hypoxia. HBO provides an effective method for fast oxygen delivery in medical practice. The exact mechanism of the oxygen transport under HBO conditions is not fully identified. The objective of this article is to extend the colloid and surface science basis for the oxygen transport in HBO conditions beyond the molecular diffusion transport mechanism. At a pressure in the hyperbaric chamber of two atmospheres, the partial pressure of oxygen in the blood plasma increases 10 times. The sharp increase of oxygen concentration in the blood plasma creates a considerable concentration gradient between the oxygen dissolved in the plasma and in the tissue. The concentration gradient of oxygen as a non-electrolyte solute causes an osmotic flow of blood plasma with dissolved oxygen. In other words, the molecular diffusion transport of oxygen is supplemented by the convective diffusion raised due to the osmotic flow, accelerating the oxygen delivery from blood to tissue. A non steady state equation for non-electrolyte osmosis is solved asymptotically. The solution clearly demonstrates two modes of osmotic flow: normal osmosis, directed from lower to higher solute concentrations, and anomalous osmosis, directed from higher to lower solute concentrations. The fast delivery of oxygen from blood to tissue is explained on the basis of the strong molecular interaction between the oxygen and the tissue, causing an influx of oxygen into the tissue by convective diffusion in the anomalous osmosis process. The transport of the second gas, nitrogen, dissolved in the blood plasma, is also taken into the consideration. As the patient does not inhale nitrogen during HBO treatment, but exhales it along with oxygen and carbon dioxide, the concentration of nitrogen in blood

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

Science.gov (United States)

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

2015-07-16

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

The Relationship Between Oxygen Reserve Index and Arterial Partial Pressure of Oxygen During Surgery.

Science.gov (United States)

Applegate, Richard L; Dorotta, Ihab L; Wells, Briana; Juma, David; Applegate, Patricia M

2016-09-01

The use of intraoperative pulse oximetry (SpO2) enhances hypoxia detection and is associated with fewer perioperative hypoxic events. However, SpO2 may be reported as 98% when arterial partial pressure of oxygen (PaO2) is as low as 70 mm Hg. Therefore, SpO2 may not provide advance warning of falling arterial oxygenation until PaO2 approaches this level. Multiwave pulse co-oximetry can provide a calculated oxygen reserve index (ORI) that may add to information from pulse oximetry when SpO2 is >98%. This study evaluates the ORI to PaO2 relationship during surgery. We studied patients undergoing scheduled surgery in which arterial catheterization and intraoperative arterial blood gas analysis were planned. Data from multiple pulse co-oximetry sensors on each patient were continuously collected and stored on a research computer. Regression analysis was used to compare ORI with PaO2 obtained from each arterial blood gas measurement and changes in ORI with changes in PaO2 from sequential measurements. Linear mixed-effects regression models for repeated measures were then used to account for within-subject correlation across the repeatedly measured PaO2 and ORI and for the unequal time intervals of PaO2 determination over elapsed surgical time. Regression plots were inspected for ORI values corresponding to PaO2 of 100 and 150 mm Hg. ORI and PaO2 were compared using mixed-effects models with a subject-specific random intercept. ORI values and PaO2 measurements were obtained from intraoperative data collected from 106 patients. Regression analysis showed that the ORI to PaO2 relationship was stronger for PaO2 to 240 mm Hg (r = 0.536) than for PaO2 over 240 mm Hg (r = 0.0016). Measured PaO2 was ≥100 mm Hg for all ORI over 0.24. Measured PaO2 was ≥150 mm Hg in 96.6% of samples when ORI was over 0.55. A random intercept variance component linear mixed-effects model for repeated measures indicated that PaO2 was significantly related to ORI (β[95% confidence interval] = 0

Oxygen Tension in the Aqueous Humor of Human Eyes under Different Oxygenation Conditions

Directory of Open Access Journals (Sweden)

Farideh Sharifipour

2013-01-01

Full Text Available Purpose: To measure oxygen tension in the aqueous humor of human eyes under different oxygenation conditions. Methods: This prospective comparative interventional case series consisted of two parts. In the first part, 120 consecutive patients scheduled for cataract surgery were randomized into group I (control group in which surgery was performed under local anesthesia inhaling 21% oxygen; group II in whom general anesthesia using 50% oxygen was employed; and group III receiving general anesthesia with 100% oxygen. After aspirating 0.2 ml aqueous humor under sterile conditions, the aqueous sample and a simultaneously drawn arterial blood sample were immediately analyzed using a blood gas analyzer. In part II the same procedures were performed in 10 patients after fitting a contact lens and patching the eye for 20 minutes (group IV and in 10 patients after transcorneal delivery of oxygen at a flow rate of 5 L/min (group V. Results: Mean aqueous PO2 in groups I, II and III was 112.3±6.2, 141.1±20.4, and 170.1±27 mmHg, respectively (P values <0.001 and mean arterial PO2 was 85.7±7.9, 184.6±46, and 379.1±75.9 mmHg, respectively (P values <0.001. Aqueous PO2 was 77.2±9.2 mmHg in group IV and 152.3±10.9 mmHg in group V (P values <0.001. There was a significant correlation between aqueous and blood PO2 (r=0.537, P<0.001. The contribution of atmospheric oxygen to aqueous PO2 was 23.7%. Conclusion: Aqueous oxygen tension is mostly dependent on the systemic circulation and in part on the atmosphere. Increasing inspiratory oxygen and transcorneal oxygen delivery both increase aqueous PO2 levels.

Relationship between oxygen delivery and its compensatory factors and acute mountain sickness

Directory of Open Access Journals (Sweden)

Ming LI

2013-03-01

Full Text Available Objective 　To investigate the changes in oxygen delivery (DO2 to the body and brain and its compensatory factors to acute hypoxia and their relation to acute mountain sickness (AMS. Methods 　One hundred and forty-seven participants were recruited from Chinese young men who had lived in plain all along arrived in Tibet by flight. All of them were asked to complete an AMS questionnaire within 48h after arrival. The resting heart rate (HR, blood pressure (BP, cardiac output (CO, oxygen saturation (SaO2, stroke volume (SV and blood flow velocity in the middle cerebral artery (MCAv were measured one week before departure from the plain and within 48h after arrival in Tibet. AMS was diagnosed according to Louis Lake Score System (LLS, and the results were then statistically analyzed. Results 　AMS was diagnosed in eighty-six subjects (58.5%. After exposure to hypoxia, SaO2 was decreased by 10% and was negatively correlated with AMS score. Systemic DO2, CO and HR were increased by 19%, 32.5% and 31.7%, respectively, and were positively correlated with AMS, while the SV remained unchanged. MCAv accelerated by 10%, and that of AMS subjects was higher than of non-AMS ones. The cerebral DO2 (DO2C was maintained because the MCAv matched with SaO2 changes. The middle cerebral artery resistance units (RMCA decreased obviously with an increase in MBP, and RMCA in AMS subjects was lower than that in non-AMS ones. HR and MCAv, the key compensation factors of DO2, were used as the objective evaluation indices, in collaboration of HR≥85 beat/min and MCAv≥66cm/s, could be a better means to evaluate AMS, with a positive predictive value of 82.4% and specificity of 90.2%. Conclusions 　DO2 and its compensatory factors may play a key role in the regulation response to acclimatize to acute hypoxia. Among them, HR and MCAv may relate to the mechanism of AMS development, and indirectly reflect the compensation level to oxygen debt, implying that HR and MCAv are

The influence of systemic hemodynamics and oxygen transport on cerebral oxygen saturation in neonates after the Norwood procedure.

Science.gov (United States)

Li, Jia; Zhang, Gencheng; Holtby, Helen; Guerguerian, Anne-Marie; Cai, Sally; Humpl, Tilman; Caldarone, Christopher A; Redington, Andrew N; Van Arsdell, Glen S

2008-01-01

Ischemic brain injury is an important morbidity in neonates after the Norwood procedure. Its relationship to systemic hemodynamic oxygen transport is poorly understood. Sixteen neonates undergoing the Norwood procedure were studied. Continuous cerebral oxygen saturation was measured by near-infrared spectroscopy. Continuous oxygen consumption was measured by respiratory mass spectrometry. Pulmonary and systemic blood flow, systemic vascular resistance, oxygen delivery, and oxygen extraction ratio were derived with measurements of arterial, and superior vena cava and pulmonary venous gases and pressures at 2- to 4-hour intervals during the first 72 hours in the intensive care unit. Mean cerebral oxygen saturation was 66% +/- 12% before the operation, reduced to 51% +/- 13% on arrival in the intensive care unit, and remained low during the first 8 hours; it increased to 56% +/- 9% at 72 hours, still significantly lower than the preoperative level (P blood flow and oxygen delivery (P blood flow (P = .001) and hemoglobin (P = .02) and negatively correlated with systemic vascular resistance (P = .003). It was not correlated with oxygen consumption (P > .05). Cerebral oxygen saturation decreased significantly in neonates during the early postoperative period after the Norwood procedure and was significantly influenced by systemic hemodynamic and metabolic events. As such, hemodynamic interventions to modify systemic oxygen transport may provide further opportunities to reduce the risk of cerebral ischemia and improve neurodevelopmental outcomes.

'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.

Investigation of Factors Affecting Microdialysis Probe Delivery and ...

African Journals Online (AJOL)

Conclusion: The in vitro experiments indicate that it would be incorrect to equate delivery with recovery of puerarin in in vivo microdialysis experiments. Keywords: Microdialysis, Puerarin, Recovery, Probe delivery. Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (SciSearch), Scopus,.

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....

The ideal oxygen/nitrous oxide fresh gas flow sequence with the Anesthesia Delivery Unit machine.

Science.gov (United States)

Hendrickx, Jan F A; Cardinael, Sara; Carette, Rik; Lemmens, Hendrikus J M; De Wolf, Andre M

2007-06-01

To determine whether early reduction of oxygen and nitrous oxide fresh gas flow from 6 L/min to 0.7 L/min could be accomplished while maintaining end-expired nitrous oxide concentration > or =50% with an Anesthesia Delivery Unit anesthesia machine. Prospective, randomized clinical study. Large teaching hospital in Belgium. 53 ASA physical status I and II patients requiring general endotracheal anesthesia and controlled mechanical ventilation. Patients were randomly assigned to one of 4 groups depending on the duration of high oxygen/nitrous oxide fresh gas flow (two and 4 L/min, respectively) before lowering total fresh gas flow to 0.7 L/min (0.3 and 0.4 L/min oxygen and nitrous oxide, respectively): one, two, three, or 5 minutes (1-minute group, 2-minute group, 3-minute group, and 5-minute group), with n = 10, 12, 13, and 8, respectively. The course of the end-expired nitrous oxide concentration and bellows volume deficit at end-expiration was compared among the 4 groups during the first 30 minutes. At the end of the high-flow period the end-expired nitrous oxide concentration was 35.6 +/- 6.2%, 48.4 +/- 4.8%, 53.7 +/- 8.7%, and 57.3 +/- 1.6% in the 4 groups, respectively. Thereafter, the end-expired nitrous oxide concentration decreased to a nadir of 36.1 +/- 4.5%, 45.4 +/- 3.8%, 50.9 +/- 6.1%, and 55.4 +/- 2.8% after three, 4, 6, and 8 minutes after flows were lowered in the 1- to 5-minute groups, respectively. A decrease in bellows volume was observed in most patients, but was most pronounced in the 2-minute group. The bellows volume deficit gradually faded within 15 to 20 minutes in all 4 groups. A 3-minute high-flow period (oxygen and nitrous oxide fresh gas flow of 2 and 4 L/min, respectively) suffices to attain and maintain end-expired nitrous oxide concentration > or =50% and ensures an adequate bellows volume during the ensuing low-flow period.

Does recombinant human Epo increase exercise capacity by means other than augmenting oxygen transport?

DEFF Research Database (Denmark)

Lundby, C; Robach, P; Boushel, R

2008-01-01

This study was performed to test the hypothesis that administration of recombinant human erythropoietin (rHuEpo) in humans increases maximal oxygen consumption by augmenting the maximal oxygen carrying capacity of blood. Systemic and leg oxygen delivery and oxygen uptake were studied during...... before rHuEpo treatment). Blood buffer capacity remained unaffected by rHuEpo treatment and hemodilution. The augmented hematocrit did not compromise peak cardiac output. In summary, in healthy humans, rHuEpo increases maximal oxygen consumption due to augmented systemic and muscular peak oxygen delivery....

Kinetic therapy improves oxygenation in critically ill pediatric patients.

Science.gov (United States)

Schultz, Theresa Ryan; Lin, Richard; Francis, Barbara A; Hales, Roberta L; Colborn, Shawn; Napoli, Linda A; Helfaer, Mark A

2005-07-01

To compare changes in oxygenation after manual turning and percussion (standard therapy) and after automated rotation and percussion (kinetic therapy). Randomized crossover trial. General and cardiac pediatric intensive care units. Intubated and mechanically ventilated pediatric patients who had an arterial catheter and no contraindications to using a PediDyne bed. Patients were placed on a PediDyne bed (Kinetic Concepts) and received 18 hrs blocks of standard and kinetic therapy in an order determined by randomization. Arterial blood gases were measured every 2 hrs during each phase of therapy. Oxygenation index and arterial-alveolar oxygen tension difference [P(A-a)O(2)] were calculated. Indexes calculated at baseline and after each 18-hr phase of therapy were analyzed. Fifty patients were enrolled. Data from 15 patients were either not collected or not used due to reasons that included violation of protocol and inability to tolerate the therapies in the study. Indexes of oxygenation were not normally distributed and were compared using Wilcoxon signed rank testing. Both therapies led to improvements in oxygenation, but only those from kinetic therapy achieved statistical significance. In patients receiving kinetic therapy first, median oxygenation index decreased from 7.4 to 6.19 (p = .015). The median P(A-a)O(2) decreased from 165.2 to 126.4 (p = .023). There were continued improvements in oxygenation after the subsequent period of standard therapy, with the median oxygenation index decreasing to 5.52 and median P(A-a)O(2) decreasing to 116.0, but these changes were not significant (p = .365 and .121, respectively). When standard therapy was first, the median oxygenation index decreased from 8.83 to 8.71 and the median P(a-a)o(2) decreased from 195.4 to 186.6. Neither change was significant. Median oxygenation index after the subsequent period of kinetic therapy was significantly lower (7.91, p = .044) and median P(A-a)O(2) trended lower (143.4, p = .077

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.

'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

Sex differences in the oxygen delivery, extraction, and uptake during moderate-walking exercise transition.

Science.gov (United States)

Beltrame, Thomas; Villar, Rodrigo; Hughson, Richard L

2017-09-01

Previous studies in children and older adults demonstrated faster oxygen uptake (V̇O 2 ) kinetics in males compared with females, but young healthy adults have not been studied. We hypothesized that young men would have faster aerobic system dynamics in response to the onset of exercise than women. Interactions between oxygen supply and utilization were characterized by the dynamics of V̇O 2 , deoxyhemoglobin (HHb), tissue saturation index (TSI), cardiac output (Q̇), and calculated arteriovenous O 2 difference (a-vO 2 diff ) in women and men. Eighteen healthy active young women and men (9 of each sex) with similar aerobic fitness levels volunteered for this study. Participants performed an incremental cardiopulmonary treadmill exercise test and 3 moderate-intensity treadmill exercise tests (at 80% V̇O 2 of gas exchange threshold). Data related to the moderate exercise were submitted to exponential data modelling to obtain parameters related to the aerobic system dynamics. The time constants of V̇O 2 , a-vO 2 diff , HHb, and TSI (30 ± 6, 29 ± 1, 16 ± 1, and 15 ± 2 s, respectively) in women were statistically (p < 0.05) faster than the time constants in men (42 ± 10, 49 ± 21, 19 ± 3, and 20 ± 4 s, respectively). Although Q̇ dynamics were not statistically different (p = 0.06) between groups, there was a trend to slower Q̇ dynamics in men corresponding with the slower V̇O 2 kinetics. These results indicated that the peripheral and pulmonary oxygen extraction dynamics were remarkably faster in women. Thus, contrary to the hypothesis, V̇O 2 dynamics measured at the mouth at the onset of submaximal treadmill walking were faster in women compared with men.

Impaired Muscle Oxygenation and Elevated Exercise Blood Pressure in Hypertensive Patients: Links With Vascular Stiffness.

Science.gov (United States)

Dipla, Konstantina; Triantafyllou, Areti; Koletsos, Nikolaos; Papadopoulos, Stavros; Sachpekidis, Vasileios; Vrabas, Ioannis S; Gkaliagkousi, Eugenia; Zafeiridis, Andreas; Douma, Stella

2017-08-01

This study examined in vivo (1) skeletal muscle oxygenation and microvascular function, at rest and during handgrip exercise, and (2) their association with macrovascular function and exercise blood pressure (BP), in newly diagnosed, never-treated patients with hypertension and normotensive individuals. Ninety-one individuals (51 hypertensives and 40 normotensives) underwent office and 24-hour ambulatory BP, arterial stiffness, and central aortic BP assessment, followed by a 5-minute arterial occlusion and a 3-minute submaximal handgrip exercise. Changes in muscle oxygenated and deoxygenated hemoglobin and tissue oxygen saturation were continuously monitored by near-infrared spectroscopy and beat-by-beat BP by Finapres. Hypertensives had higher ( P age and body mass index (BMI) adjusted). When exercising at the same submaximal intensity, hypertensives required a significantly greater ( P hypertension exhibit prominent reductions in in vivo indices of skeletal muscle oxidative capacity, suggestive of mitochondrial dysfunction, and blunted muscle microvascular reactivity. These dysfunctions were associated with higher aortic systolic BP and arterial stiffness. Dysregulations in muscle oxygen delivery/utilization and microvascular stiffness, in hypertensive patients, partially contribute to their exaggerated BP during exercise. © 2017 American Heart Association, Inc.

Efficacy of a portable oxygen concentrator with pulsed delivery for treatment of hypoxemia during equine field anesthesia.

Science.gov (United States)

Coutu, Paige; Caulkett, Nigel; Pang, Daniel; Boysen, Søren

2015-09-01

Hypoxemia is common during equine field anesthesia. Our hypothesis was that oxygen therapy from a portable oxygen concentrator would increase PaO2 during field anesthesia compared with the breathing of ambient air. Prospective clinical study. Fifteen yearling (250 - 400 kg) horses during field castration. Horses were maintained in dorsal recumbency during anesthesia with an intravenous infusion of 2000 mg ketamine and 500 mg xylazine in 1 L of 5% guaifenesin. Arterial samples for blood gas analysis were collected immediately post-induction (PI), and at 15 and 30 minutes PI. The control group (n = 6) breathed ambient air. The treatment group (n = 9) were administered pulsed-flow oxygen (192 mL per bolus) by nasal insufflation during inspiration for 15 minutes PI, then breathed ambient air. The study was performed at 1300 m above sea level. One-way and two-way repeated-measures anova with post-hoc Bonferroni tests were used for within and between-group comparisons, respectively. Significance was set at p ≤ 0.05. Mean ± SD PaO2 in controls at 0, 15 and 30 minutes PI were 46 ± 7 mmHg (6.1 ± 0.9 kPa), 42 ± 9 mmHg (5.6 ± 1.1 kPa), and 48 ± 7 mmHg (6.4 ± 0.1 kPa), respectively (p = 0.4). In treatment animals, oxygen administration significantly increased PaO2 at 15 minutes PI to 60 ± 13 mmHg (8.0 ± 1.7 kPa), compared with baseline values of 46 ± 8 mmHg (6.1 ± 1 kPa) (p = 0.007), and 30 minute PI values of 48 ± 7 mmHg (6.5 ± 0.9 kPa) (p = 0.003). These data show that a pulsed-flow delivery of oxygen can increase PaO2 in dorsally recumbent horses during field anesthesia with ketamine-xylazine-guaifenesin. The portable oxygen concentrator may help combat hypoxemia during field anesthesia in horses. © 2015 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesia and Analgesia.

Audit of the influence of body mass index on the performance of epidural analgesia in labour and the subsequent mode of delivery.

Science.gov (United States)

Dresner, M; Brocklesby, J; Bamber, J

2006-10-01

To assess the influence of body mass index (BMI) on the performance of epidural analgesia in labour and the subsequent mode of delivery. A retrospective audit of prospectively collected quality assurance data. The delivery suite of Leeds General Infirmary, Leeds, UK. This is a 4500-delivery teaching hospital unit. All women receiving epidural analgesia during labour in our unit between April 1997 and December 2005. Epidural recipients were divided into BMI groups according to World Health Organization (WHO) categories and compared for indices of epidural performance and mode of delivery. Midwife and patient satisfaction scores with epidural analgesia, epidural resite rates, and mode of delivery. Data from 13 299 epidural recipients were analysed. Using WHO definitions, 22.8% were of normal body mass, 41.9% were overweight, 31.9% obese, and 3.4% morbidly obese. Epidurals were more likely to fail as BMI increased, as judged by midwife satisfaction scores (P < 0.001) and epidural resite rates (P < 0.01). This trend was not seen for maternal satisfaction scores using the WHO BMI categories. However, if women with BMI below 30 kg/m2 were grouped together, a significant trend was found (P < 0.01). BMI had no influence on vaginal instrumental deliveries, but caesarean section rates rose from 11.5% in women of normal BMI to 29.2% in the morbidly obese women (P < 0.001). Obesity increases the incidence of analgesic failure and the need for resite of epidurals. The caesarean section rate among epidural recipients increases dramatically as BMI rises.

No oxygen delivery limitation in hepatic encephalopathy

DEFF Research Database (Denmark)

Gjedde, Albert; Keiding, Susanne; Vilstrup, Hendrik

2010-01-01

to choose between cause and effect in three groups of volunteers, including healthy control subjects (HC), patients with cirrhosis of the liver without hepatic encephalopathy (CL), and patients with cirrhosis with acute hepatic encephalopathy. Compared to HC subjects, blood flow and energy metabolism had......Hepatic encephalopathy is a condition of reduced brain functioning in which both blood flow and brain energy metabolism declined. It is not known whether blood flow or metabolism is the primary limiting factor of brain function in this condition. We used calculations of mitochondrial oxygen tension...

Mechanisms controlling the oxygen consumption in experimentally induced hypochloremic alkalosis in calves.

Science.gov (United States)

Cambier, Carole; Clerbaux, Thierry; Amory, Hélène; Detry, Bruno; Florquin, Sandra; Marville, Vincent; Frans, Albert; Gustin, Pascal

2002-01-01

The study was carried out on healthy Friesian calves (n = 10) aged between 10 and 30 days. Hypochloremia and alkalosis were induced by intravenous administration of furosemide and isotonic sodium bicarbonate. The venous and arterial blood samples were collected repeatedly. 2,3-diphosphoglycerate (2,3-DPG), hemoglobin and plasmatic chloride concentrations were determined. The red blood cell chloride concentration was also calculated. pH, PCO2 and PO2 were measured in arterial and mixed venous blood. The oxygen equilibrium curve (OEC) was measured in standard conditions. The correspondence of the OEC to the arterial and mixed venous compartments was calculated, taking blood temperature, pH and PCO2 values into account. The oxygen exchange fraction (OEF%), corresponding to the degree of blood desaturation between the arterial and mixed venous compartments and the amount of oxygen released at the tissue level by 100 mL of blood (OEF Vol%) were calculated from the arterial and mixed venous OEC, combined with PO2 and hemoglobin concentration. Oxygen delivery (DO2) was calculated using the arterial oxygen content, the cardiac output measured by thermodilution, and the body weight of the animal. The oxygen consumption (VO2) was derived from the cardiac output, OEF Vol% and body weight values. Despite the plasma hypochloremia, the erythrocyte chloride concentration was not influenced by furosemide and sodium bicarbonate infusion. Due to the alkalosis-induced increase in the 2,3-DPG, the standard OEC was shifted to the right, allowing oxygen to dissociate from hemoglobin more rapidly. These changes opposed the increased affinity of hemoglobin for oxygen induced by alkalosis. Moreover, respiratory acidosis, hemoconcentration, and the slight decrease in the partial oxygen pressure in mixed venous blood (Pvo2) tended to improve the OEF Vol% and maintain the oxygen consumption in a physiological range while the cardiac output, and the oxygen delivery were significantly decreased

A theoretical model for the effects of reduced hemoglobin-oxygen affinity on tumor oxygenation

International Nuclear Information System (INIS)

Kavanagh, Brian D.; Secomb, Timothy W.; Hsu, Richard; Lin, P.-S.; Venitz, Jurgen; Dewhirst, Mark W.

2002-01-01

Purpose: To develop a theoretical model for oxygen delivery to tumors, and to use the model to simulate the effects of changing the affinity of hemoglobin for oxygen on tumor oxygenation. Methods and Materials: Hemoglobin affinity is expressed in terms of P 50 , the partial pressure of oxygen (Po 2 ) at half saturation. Effects of changing P 50 on arterial Po 2 are predicted using an effective vessel approach to describe diffusive oxygen transport in the lungs, assuming fixed systemic oxygen demand and fixed blood flow rate. The decline in oxygen content of blood as it flows through normal tissue before entering the tumor region is assumed fixed. The hypoxic fraction of the tumor region is predicted using a three-dimensional simulation of diffusion from a network of vessels whose geometry is derived from observations of tumor microvasculature in the rat. Results: In air-breathing rats, predicted hypoxic fraction decreases with moderate increases in P 50 , but increases with further increases of P 50 , in agreement with previous experimental results. In rats breathing hyperoxic gases, and in humans breathing either normoxic or hyperoxic gases, increased P 50 is predicted to improve tumor oxygenation. Conclusions: The results support the administration of synthetic agents to increase P 50 during radiation treatment of tumors

Placental Gas Exchange and the Oxygen Supply to the Fetus

DEFF Research Database (Denmark)

Carter, Anthony M

2015-01-01

The oxygen supply of the fetus depends on the blood oxygen content and flow rate in the uterine and umbilical arteries and the diffusing capacity of the placenta. Oxygen consumption by the placenta is a significant factor and a potential limitation on availability to the fetus. The relevance...... anaerobic conditions and even the fetus is adapted to a low oxygen environment. Nevertheless, there is a reserve capacity, and during acute hypoxia the fetus can counter a 50% reduction in oxygen delivery by increasing fractional extraction. During sustained hypoxia, on the other hand, fetal growth...

Comparison of oxygen saturation levels in patients receiving Technegas by the conventional unassisted method vs. the positive ventilation delivery system (PVDS)

International Nuclear Information System (INIS)

Dobson, M.P.; Leiper, C.A.; Lee, K.; Dixson, H.

2000-01-01

Full text: The purpose of this study is to compare oxygen saturation levels (SaO 2 ) in 289 patients undergoing conventional lung ventilation scintigraphy (control group) and 27 patients undergoing Positive Ventilation Delivery System (PVDS). The 27 patients where selected as their conventional method of inhalation proved to be inadequate or non-diagnostic. The patients underwent a second ventilation using PVDS, which improved the diagnostic quality of the ventilation image and assisted in clinical management decisions. Some patients in both the PVDS and the control group experienced a transient lowering in their SaO 2 . The mean initial SaO 2 in the control group did not fall below 94.9% and in the PVDS group measured 90.6%. 93% (25/27) of patients in the PVDS group were assessed as non CO 2 retaining, and received oxygen at 10L/min during Technegas inhalation. The mean trough saturation in the PVDS group was 91.7% which was significantly higher than that of the control group (86.9%). No patient in either group experienced any significant complication attributed to the transient tall in SaO 2 during technegas administration. We conclude that oxygen supplied as part of the PVDS system ameliorates the transient reduction in SaO 2 seen during standard Technegas administration. Copyright (2000) The Australian and New Zealand Society of Nuclear Medicine Inc

Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

Science.gov (United States)

Liu, Jie; Liu, Yang; Ren, Li-Hua; Li, Li; Wang, Zhen; Liu, Shan-Shan; Li, Su-Zhi; Cao, Tie-Sheng

2016-08-01

To assess racial, sexual, and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = QICA + QVA), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and QVA/TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation, and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (-17% vs. 0%), TCVR (22% vs. 12%), TCOD (0% vs. 10%) and QVA/TCBF (0% vs. 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.

Oxygen consumption and blood flow coupling in human motor cortex during intense finger tapping

DEFF Research Database (Denmark)

Seyedi Vafaee, Manouchehr; Vang, Kim; Bergersen, Linda H

2012-01-01

Rates of cerebral blood flow (CBF) and glucose consumption (CMR(glc)) rise in cerebral cortex during continuous stimulation, while the oxygen-glucose index (OGI) declines as an index of mismatched coupling of oxygen consumption (cerebral metabolic rate of oxygen-CMRO(2)) to CBF and CMR(glc). To t...

Effects of whole body UV-irradiation on oxygen delivery from the erythrocyte

International Nuclear Information System (INIS)

Humpeler, E.; Mairbaeurl, H.; Hoenigsmann, H.

1982-01-01

In 16 healthy caucasian volunteers (mean age: 22.2 years) the influence of whole body UV-irradiation on the oxygen transport properties of erythrocytes was investigated. Four hours after irradiation with UV (using the minimal erythema dose, MED) no variation of haemoglobin concentration, hematocrit, mean corpuscular haemoglobin concentration, pH or standard bicarbonate could be found, whereas inorganic plasma phosphate (Psub(i)), calcium, the intraerythrocytic 2,3-diphosphoglycerate (2,3-DPG), the activity of erythrocytic phosphofructokinase (PFK) and pyruvatekinase (PK) increased significantly. The half saturation tension of oxygen (P 50 -value) tended to increase. The increase of Psub(i) causes - via a stimulation of the glycolytic pathway - an increase in 2,3-DPG concentration and thus results in a shift of the oxygen dissociation curve. It is therefore possible to enhance tissue oxygenation by whole body UV-irradiation. (orig.)

An in silico analysis of oxygen uptake of a mild COPD patient during rest and exercise using a portable oxygen concentrator

Directory of Open Access Journals (Sweden)

Katz I

2016-09-01

Full Text Available Ira Katz,1,2 Marine Pichelin,1 Spyridon Montesantos,1 Min-Yeong Kang,3 Bernard Sapoval,3,4 Kaixian Zhu,5 Charles-Philippe Thevenin,5 Robert McCoy,6 Andrew R Martin,7 Georges Caillibotte1 1Medical R&D, Air Liquide Santé International, Centre de Recherche Paris-Saclay, Les Loges-en-Josas, France; 2Department of Mechanical Engineering, Lafayette College, Easton, PA, USA; 3Physique de la Matière Condensée, CNRS, Ecole Polytechnique, Palaiseau, 4Centre de Mathématiques et de leurs Applications, CNRS, UniverSud, Cachan, 5Centre Explor!, Air Liquide Healthcare, Gentilly, France; 6Valley Inspired Products, Inc, Apple Valley, MN, USA; 7Department of Mechanical Engineering, University of Alberta, Edmonton, AB, Canada Abstract: Oxygen treatment based on intermittent-flow devices with pulse delivery modes available from portable oxygen concentrators (POCs depends on the characteristics of the delivered pulse such as volume, pulse width (the time of the pulse to be delivered, and pulse delay (the time for the pulse to be initiated from the start of inhalation as well as a patient’s breathing characteristics, disease state, and respiratory morphology. This article presents a physiological-based analysis of the performance, in terms of blood oxygenation, of a commercial POC at different settings using an in silico model of a COPD patient at rest and during exercise. The analysis encompasses experimental measurements of pulse volume, width, and time delay of the POC at three different settings and two breathing rates related to rest and exercise. These experimental data of device performance are inputs to a physiological-based model of oxygen uptake that takes into account the real dynamic nature of gas exchange to illustrate how device- and patient-specific factors can affect patient oxygenation. This type of physiological analysis that considers the true effectiveness of oxygen transfer to the blood, as opposed to delivery to the nose (or mouth, can be

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.

Factors determining the choice of a place of delivery among ...

African Journals Online (AJOL)

85 (60.7%) chose to deliver in the hospital, while 55 (39.3%) opted for home delivery in the index pregnancy. Determinants of choice of delivery place include cost of hospital bill ... thus achieving the millennium development goals (MDGs) 4 and 5. Keywords: Factors, delivery, birth attendants, pregnant women, MDGs ...

Wealth index and maternal health care: Revisiting NFHS-3.

Science.gov (United States)

Goel, Manish Kr; Roy, Pritam; Rasania, Sanjeev Kumar; Roy, Sakhi; Kumar, Yogesh; Kumar, Arun

2015-01-01

The third National Family Health Survey (NFHS-3) is a large dataset on indicators of family welfare, maternal and child health, and nutrition in India. This article using NFHS-3 data is an attempt to bring out the impact of economic status, i.e., the wealth index on maternal health. The study was based on an analysis of the NFHS-3 data. Independent variables taken were the wealth index, literacy, and age at first child birth. Effects of these variables on the maternal health care services were investigated. Out of the total 124,385 women aged 15-49 years included in the NFHS-3 dataset, 36,850 (29.6%) had one or more childbirth during the past 5 years. The number of antenatal care (ANC) visits increased as the wealth index increased and there was a pattern for choice of place of delivery (for all deliveries during the last 5 years) according to the wealth index. Logistic regression analysis of the abovementioned variables were sought to find out the independent role of key determinants of the different aspects of maternal health care. It showed that the wealth index is the leading key independent determinant for three or more ANC received: Tetanus toxoid (TT) received before delivery, iron tablet/syrup taken for more than 100 days, and institutional delivery. Mother's literacy was the leading independent key determinant for early antenatal registration. The study suggested that along with the mother's literacy, the wealth index that is an important predictor of maternal health care can be added for categorization of the districts for providing differential approach for maternal health care services.

Is Hypoxia common despite oxygen treatment in the Acute Medical ...

African Journals Online (AJOL)

The delivery of oxygen in an acute Admissions Unit is always (often) riddled with difficulties. While most patients do get oxygen at some point of time it is often uncontrolled and inappropriate. This reflects inadequate and untrained staffing in the very busy Medical Units. We did a small study on 30 random acute admissions ...

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.

A bench evaluation of fraction of oxygen in air delivery and tidal volume accuracy in home care ventilators available for hospital use

Science.gov (United States)

Baboi, Loredana; Subtil, Fabien

2016-01-01

Background Turbine-powered ventilators are not only designed for long-term ventilation at home but also for hospital use. It is important to verify their capabilities in delivering fraction of oxygen in air (FIO2) and tidal volume (VT). Methods We assessed the FIO2 accuracy and the VT delivery in four home care ventilators (HCV) on the bench. The four HCV were Astral 150, Elisée 150, Monnal T50 and Trilogy 200 HCV, which were connected to a lung model (ASL 5000). For assessing FIO2 accuracy, lung model was set to mimic an obstructive lung and HCV were set in volume controlled mode (VC). They supplied with air, 3 or 15 L/min oxygen and FIO2 was measured by using a ventilator tester (Citrex H4TM). For the VT accuracy, the lung model was set in a way to mimic three adult configurations (normal, obstructive, or restrictive respiratory disorder) and one pediatric configuration. Each HCV was set in VC. Two VT (300 and 500 mL) in adult lung configuration and one 50 mL VT in pediatric lung configuration, at two positive end expiratory pressures 5 and 10 cmH2O, were tested. VT accuracy was measured as volume error (the relative difference between set and measured VT). Statistical analysis was performed by suing one-factor ANOVA with a Bonferroni correction for multiple tests. Results For Astral 150, Elisée 150, Monnal T50 and Trilogy 200, FIO2 averaged 99.2%, 93.7%, 86.3%, and 62.1%, respectively, at 15 L/min oxygen supplementation rate (P<0.001). Volume error was 0.5%±0%, −38%±0%, −9%±0%, −29%±0% and −36%±0% for pediatric lung condition (P<0.001). In adult lung configurations, Monnal T50 systematically over delivered VT and Trilogy 150 was sensitive to lung configuration when VT was set to 300 mL at either positive end-expiratory pressure (PEEP). Conclusions HCV are different in terms of FIO2 efficiency and VT delivery. PMID:28149559

Intestinal and cerebral oxygenation during severe isovolemic hemodilution and subsequent hyperoxic ventilation in a pig model

NARCIS (Netherlands)

van Bommel, Jasper; Trouwborst, Adrianus; Schwarte, Lothar; Siegemund, Martin; Ince, Can; Henny, Ch Pieter

2002-01-01

Background: During severe isovolemic hemodilution, determination of critical hematocrit levels for the microvascular oxygenation of different organs might provide more insight into the effect of the redistribution of blood flow and oxygen delivery on the oxygenation of different organs. The effect

Low blood flow at onset of moderate-intensity exercise does not limit muscle oxygen uptake

DEFF Research Database (Denmark)

Nyberg, Michael Permin; Mortensen, Stefan P; Saltin, Bengt

2010-01-01

The effect of low blood flow at onset of moderate-intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5-min one-legged knee-extensor exercise bout (24 +/- 1 W, mean +/- SD) without (Con) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (N(G)-monomethyl-l-arginine) and cyclooxygenase (indomethacin) to inhibit the synthesis of nitric oxide and prostanoids, respectively. Leg blood flow and leg oxygen delivery throughout exercise was 25-50% lower (P ... +/- 12 vs. 262 +/- 39 ml/min). The present data demonstrate that muscle blood flow and oxygen delivery can be markedly reduced without affecting muscle oxygen uptake in the initial phase of moderate-intensity exercise, suggesting that blood flow does not limit muscle oxygen uptake at the onset...

Erectile dysfunction is independently associated with apnea-hypopnea index and oxygen desaturation index in elderly, but not younger, community-dwelling men.

Science.gov (United States)

Martin, Sean A; Appleton, Sarah L; Adams, Robert J; Taylor, Anne W; Vincent, Andrew; Brook, Nicholas R; Catcheside, Peter G; Vakulin, Andrew; McEvoy, R Douglas; Antic, Nick A; Wittert, Gary A

2017-08-01

To examine the association between obstructive sleep apnea (OSA) and other sleep indices using polysomnography (PSG) data and erectile dysfunction (ED) in a representative cohort of men. Cross-sectional. Community-based. Aged 40+ years (n=734; mean age [SD], 60.8 [10.9]). Men with no prior OSA diagnosis who underwent in-home PSG (Embletta X100; 2010-11) and ED assessment (Global Impotence Rating) were selected. Un-adjusted and multi-adjusted regression models of ED were fitted against PSG measures, along with qualifying sociodemographic, lifestyle, and health-related covariates. Mediation effects were examined using the Baron-Kenny method. Of the men examined, 24.7% (n=181) had ED, most notably in men older than 65years (cf. men 35-49 and 50-64years; Pmen. Given an observed ageinteraction within OSA categories (P=.005), analyses were repeated in age-stratified samples (men younger than 65years, only severe OSA was found to have an association with ED (2.01; 1.13-4.69) in unadjusted models. For men aged 65+ years, an independent association with ED was found for apnea-hyponea index (AHI; 1.55;1.02-2.36), moderate (AHI:10.0-19.9; 1.79;1.18-2.43), and severe (AHI:20.0+; 4.84;2.56-9.93) OSA, and oxygen desaturation index (ODI; both continuous [1.48;1.03-1.99] and >16 seconds [2.79;1.23-6.32]). The effect of AHI on ED was shown to be primarily mediated through ODI (63.4%, Sobel P value=.29). In younger, community-based men, there appeared no independent relationship between objective measures of sleep and ED. However, there appears a strong, independent relationship between OSA, ODI, and ED in men 65 years and older. Copyright © 2017 National Sleep Foundation. All rights reserved.

Smart Drug Delivery Systems in Cancer Therapy.

Science.gov (United States)

Unsoy, Gozde; Gunduz, Ufuk

2018-02-08

Smart nanocarriers have been designed for tissue-specific targeted drug delivery, sustained or triggered drug release and co-delivery of synergistic drug combinations to develop safer and more efficient therapeutics. Advances in drug delivery systems provide reduced side effects, longer circulation half-life and improved pharmacokinetics. Smart drug delivery systems have been achieved successfully in the case of cancer. These nanocarriers can serve as an intelligent system by considering the differences of tumor microenvironment from healthy tissue, such as low pH, low oxygen level, or high enzymatic activity of matrix metalloproteinases. The performance of anti-cancer agents used in cancer diagnosis and therapy is improved by enhanced cellular internalization of smart nanocarriers and controlled drug release. Here, we review targeting, cellular internalization; controlled drug release and toxicity of smart drug delivery systems. We are also emphasizing the stimulus responsive controlled drug release from smart nanocarriers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Relating oxygen partial pressure, saturation and content: the haemoglobin-oxygen dissociation curve.

Science.gov (United States)

Collins, Julie-Ann; Rudenski, Aram; Gibson, John; Howard, Luke; O'Driscoll, Ronan

2015-09-01

The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content), saturation (S O2 ) and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin-oxygen dissociation curve, a graphical representation of the relationship between oxygen satur-ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the S O2 in blood from patients with normal pH and S O2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (S pO2 ) is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (S aO2 ) as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable S pO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

Relating oxygen partial pressure, saturation and content: the haemoglobin–oxygen dissociation curve

Directory of Open Access Journals (Sweden)

Julie-Ann Collins

2015-09-01

The delivery of oxygen by arterial blood to the tissues of the body has a number of critical determinants including blood oxygen concentration (content, saturation (SO2 and partial pressure, haemoglobin concentration and cardiac output, including its distribution. The haemoglobin–oxygen dissociation curve, a graphical representation of the relationship between oxygen satur­ation and oxygen partial pressure helps us to understand some of the principles underpinning this process. Historically this curve was derived from very limited data based on blood samples from small numbers of healthy subjects which were manipulated in vitro and ultimately determined by equations such as those described by Severinghaus in 1979. In a study of 3524 clinical specimens, we found that this equation estimated the SO2 in blood from patients with normal pH and SO2 >70% with remarkable accuracy and, to our knowledge, this is the first large-scale validation of this equation using clinical samples. Oxygen saturation by pulse oximetry (SpO2 is nowadays the standard clinical method for assessing arterial oxygen saturation, providing a convenient, pain-free means of continuously assessing oxygenation, provided the interpreting clinician is aware of important limitations. The use of pulse oximetry reduces the need for arterial blood gas analysis (SaO2 as many patients who are not at risk of hypercapnic respiratory failure or metabolic acidosis and have acceptable SpO2 do not necessarily require blood gas analysis. While arterial sampling remains the gold-standard method of assessing ventilation and oxygenation, in those patients in whom blood gas analysis is indicated, arterialised capillary samples also have a valuable role in patient care. The clinical role of venous blood gases however remains less well defined.

High index surfaces of Au-nanocrystals supported on one-dimensional MoO3-nanorod as a bi-functional electrocatalyst for ethanol oxidation and oxygen reduction

International Nuclear Information System (INIS)

Karuppasamy, L.; Chen, C.Y.; Anandan, S.; Wu, J.J.

2017-01-01

Highlights: •Synthesis of a new class of Au nanocrystals enclosed with high index surface supported on MoO 3 nanorods by ultrasonic probe method. •The role of supporting materials reduces the loading of Au and acts as a co-catalyst. •The as prepared electrocatalyst exhibits enhanced catalytic activity and stability towards both EOR and ORR. -- Abstract: The design of highly active electrocatalyst for ethanol electrooxidation (EOR) and oxygen reduction reaction (ORR) is of great significance for the improvement of efficient direct ethanol fuel cells (DEFCs). Therefore, creating high index facets nanocrystals with abundant catalytic active sites of stepped atoms is an effective way to enhance the electrocatalytic performance. In this article, we prepared the high index surface structures of Au nanocrystals supported on one-dimensional (1-D) MoO 3 nanorods by using two steps ultrasonic probe irradiation method. The size and physical properties of as electrocatalysts were studied by using field emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM), and x-ray diffraction (XRD) instrumentation. Besides, the catalytic activity of as Au-MoO 3 electrocatalyst was determined by using cyclic voltammetry (CV), chronoamperometric (CA), electrochemical impedance spectroscopy (EIS), CO-stripping, and linear sweep voltammetry-rotating disk electrode (LSV-RDE). As a consequence, the Au-MoO 3 nanocomposites has been considered as an effective electrocatalyst for both ethanol oxidation and oxygen reduction reaction.

Life-threatening Vesicular Bronchial Injury Requiring Veno-venous Extracorporeal Membrane Oxygenation Rescue in an Electronic Nicotine Delivery System User

Directory of Open Access Journals (Sweden)

Thomas Carter

2017-07-01

Full Text Available The use of electronic nicotine delivery systems (ENDS is increasing across the United States as tobacco bans increase and more people use these devices in an attempt to quit smoking. They are unregulated by the Food and Drug Administration, and there is significant concern that ENDS could produce several toxic byproducts. In this case a 35-year-old female presented to the emergency department with sudden-onset dyspnea. She denied current tobacco smoking, but she was a user of ENDS. When bronchoscopy was performed, an extensive pattern of suspected chemical injury was noted in her airways. She required transfer to a tertiary center where she required extracorporeal membranous oxygenation. Despite public opinion that ENDS are generally safe, or at least safer than tobacco smoking, contrary evidence is mounting. We postulate that her injuries were likely suffered secondary to use of an ENDS.

Long-term oxygen therapy for COPD. Improving longevity and quality of life in hypoxemic patients.

Science.gov (United States)

Weg, J G; Haas, C F

1998-04-01

Long-term oxygen therapy can increase life expectancy in hypoxemic patients with COPD. Accurate identification of hypoxemia requires arterial blood gas measurements. Pulse oximetry can be used to measure trends in oxygenation, oxygen needs, and oxygen requirements during exercise and sleep. A detailed oxygen prescription indicates: (1) the oxygen dose (L/min), (2) the number of hours per day that oxygen therapy is required, (3) the dose required during exercise, (4) the oxygen supply system: concentrator, compressed gas cylinder, or liquid oxygen reservoir, and (5) the delivery device: nasal cannula, demand-flow device, reservoir cannula, or transtracheal oxygen catheter.

Methanol Droplet Combustion in Oxygen-Inert Environments in Microgravity

Science.gov (United States)

Nayagam, Vedha; Dietrich, Daniel L.; Hicks, Michael C.; Williams, Forman A.

2013-01-01

The Flame Extinguishment (FLEX) experiment that is currently underway in the Combustion Integrated Rack facility onboard the International Space Station is aimed at understanding the effects of inert diluents on the flammability of condensed phase fuels. To this end, droplets of various fuels, including alkanes and alcohols, are burned in a quiescent microgravity environment with varying amounts of oxygen and inert diluents to determine the limiting oxygen index (LOI) for these fuels. In this study we report experimental observations of methanol droplets burning in oxygen-nitrogen-carbon dioxide and oxygen-nitrogen-helium gas mixtures at 0.7 and 1 atmospheric pressures. The initial droplet size varied between approximately 1.5 mm and 4 mm to capture both diffusive extinction brought about by insufficient residence time at the flame and radiative extinction caused by excessive heat loss from the flame zone. The ambient oxygen concentration varied from a high value of 30% by volume to as low as 12%, approaching the limiting oxygen index for the fuel. The inert dilution by carbon dioxide and helium varied over a range of 0% to 70% by volume. In these experiments, both freely floated and tethered droplets were ignited using symmetrically opposed hot-wire igniters and the burning histories were recorded onboard using digital cameras, downlinked later to the ground for analysis. The digital images yielded droplet and flame diameters as functions of time and subsequently droplet burning rate, flame standoff ratio, and initial and extinction droplet diameters. Simplified theoretical models correlate the measured burning rate constant and the flame standoff ratio reasonably well. An activation energy asymptotic theory accounting for time-dependent water dissolution or evaporation from the droplet is shown to predict the measured diffusive extinction conditions well. The experiments also show that the limiting oxygen index for methanol in these diluent gases is around 12% to

Dry respirometric index assessment using open and close respirometry

International Nuclear Information System (INIS)

Andreottola, G.; Dallago, L.; Ragazzi, M.

2001-01-01

The aim of this work is to compare two different approaches for the evaluation of the respirometric index of dry biodegradable solid matter. The two used tools have been built in the University of Trent. The AIR-A respirometer (Open Respirometric Index Analyser) used in the experimentation is a pilot device made by a small steel reactor kept at steady temperature. The oxygen analyser and the temperature probe are directly connected to a PC through an acquisition device which allows to follow the evolution of the system. A balance between the amount of the volatile solids, the free volume and the decrease of the oxygen allows to assess the respiration rate. The AIR-C respirometer (Close Respirometric Index Analyser) is constituted by a reactor in which the trend of the internal temperature and the total pressure are constantly measured. A basic solution inside the reactor guarantees the absorption of CO 2 allowing to associate an oxygen consumption to the measure of the total pressure. The reactor is built in order to allow a wide exchange surface between compost and atmosphere, limiting the thickness of the layer of compost in which oxygen must diffuse. A correct balance with the effect induced by the temperature allows to calculate the respirometric index, which is related to the microbic activity only in a portion of the total lasting of the test. The analysis of the generated data and the introduction of some technical modification have allowed to obtain with the two different approaches the same values for the respirometric index [it

HYPERBARIC OXYGENATION AND AEROBIC PERFORMANCE

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Irvine D. Prather

2004-03-01

Full Text Available The continuing desire to improve performance, particularly at the national and international levels, has led to the use of ergogenic aids. Ergogenic aids are defined as 'a procedure or agent that provides the athlete with a competitive edge beyond that obtained via normal training methods'. Random drug testing has been implemented in an effort to minimize an athlete's ability to gain an unfair advantage. However, other means of improving performance have been tried. Blood doping has been used to enhance endurance performance by improving oxygen delivery to working muscles. As oxygen is carried in combination with the hemoglobin, it seems logical that increasing the number of red blood cells (RBC's in the body would increase the oxygen carrying capacity to the tissues and result in improved performance. The first experiments of removing and then reinfusing blood showed a significant improvement in performance time

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.

High oxygen levels promote peel spotting in banana fruit

NARCIS (Netherlands)

Maneenuam, T.; Ketsa, S.; Doorn, van W.G.

2007-01-01

We studied the effect of high oxygen on early peel spotting in `Sucrier¿ bananas held at 25 °C and 90% RH. Fruit first ripened to colour index 3¿4 (about as yellow as green) and were then held in containers with a continuous gas flow of 18 ± 2 kPa (control) or 90 ± 2 kPa oxygen. High oxygen promoted

Improved Apnea-Hypopnea Index and Lowest Oxygen Saturation After Maxillomandibular Advancement With or Without Counterclockwise Rotation in Patients With Obstructive Sleep Apnea

DEFF Research Database (Denmark)

Knudsen, Torben B.; Laulund, Anne Sofie; Ingerslev, Janne

2015-01-01

- and postsurgical values of pharyngeal volume measured on computed tomogram or cone-beam computed tomogram and changes in Apnea-Hypopnea Index (AHI) and lowest oxygen saturation (LSAT) values after surgery. Datawere subjected to a meta-analysis based on odds ratios (OR) with 95% confidence intervals (CIs) and P...... between pharyngeal volume changes and surgical method used. Postoperative parameters included an AHI lower than 5 (OR = 14.9; 95% CI, 2.7-83.5; P = .002), an AHI lower than 20 (OR = 114.8; 95% CI, 23.5-561.1; P

Monitoring of the Adult Patient on Venoarterial Extracorporeal Membrane Oxygenation

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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.

Humidification of Blow-By Oxygen During Recovery of Postoperative Pediatric Patients: One Unit's Journey.

Science.gov (United States)

Donahue, Suzanne; DiBlasi, Robert M; Thomas, Karen

2018-02-02

To examine the practice of nebulizer cool mist blow-by oxygen administered to spontaneously breathing postanesthesia care unit (PACU) pediatric patients during Phase one recovery. Existing evidence was evaluated. Informal benchmarking documented practices in peer organizations. An in vitro study was then conducted to simulate clinical practice and determine depth and amount of airway humidity delivery with blow-by oxygen. Informal benchmarking information was obtained by telephone interview. Using a three-dimensional printed simulation model of the head connected to a breathing lung simulator, depth and amount of moisture delivery in the respiratory tree were measured. Evidence specific to PACU administration of cool mist blow-by oxygen was limited. Informal benchmarking revealed that routine cool mist oxygenated blow-by administration was not widely practiced. The laboratory experiment revealed minimal moisture reaching the mid-tracheal area of the simulated airway model. Routine use of oxygenated cool mist in spontaneously breathing pediatric PACU patients is not supported. Copyright © 2017 American Society of PeriAnesthesia Nurses. Published by Elsevier Inc. All rights reserved.

Factors associated with the use of supplemental oxygen or positive pressure ventilation in the delivery room, in infants born with a gestational age ≥ 34 weeks

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Maria Elisabeth Moreira

2016-10-01

Full Text Available Abstract Background Approximately 5–10 % of newborns require some form of resuscitationupon delivery; several factors, such as maternal abnormal conditions, gestational age and type of delivery could be responsible for this trend. This study aimed to describe the factors associated with the need for positive pressure ventilation (PPV via a mask or endotracheal tube and the use of supplemental O2 in newborns with a gestational age greater than 34 weeks in Brazil. Methods We performed a cross-sectional study and obtained data from the Birth in Brazil Survey. The inclusion criterion was a gestational age ≥34 weeks. Exclusion criteria were newborns with congenital malformations, and cases with undetermined gestational age or type of delivery (vaginal, pre labor cesarean section and cesarean section during labor. The primary outcomes were need of PPV via a mask or endotracheal tube and the use of supplemental oxygen without PPV. Confounding variables, including maternal age, source of birth payment, years of maternal schooling, previous birth, newborn presentation, multiple pregnancy, and maternal obstetric risk, were analyzed. Results We included 22,720 newborns. Of these, 2974 (13.1 % required supplementary oxygen. PPV with a bag and mask was used for 727 (3.2 % newborns and tracheal intubation for 192 (0.8 % newborns. Chest compression was necessary for 136 (0.6 % newborns and drugs administered in 114 (0.5 %. 51.3 % of newborns were delivered by cesarean section, with the majority of cesarean sections (88.7 % being performed prior to labor. Gestational age (late preterm infants: (Relative Risk-(RR 2.46; 95 % (Confidence interval-CI 1.79–3.39, maternal obstetric risk (RR 1.59; 95 % CI1.30–1.94, and maternal age of 12–19 years old (RR 1.36; 95 % CI1.06–1.74 contributed to rates of PPV in the logistic regression analysis. Newborns aged between 37–38 weeks of gestaional age weren´t less likely to require PPV compared with

Exploring educational disparities in risk of preterm delivery

DEFF Research Database (Denmark)

Poulsen, Gry; Strandberg-Larsen, Katrine; Mortensen, Laust

2015-01-01

data. METHODS: The study included data from 12 European cohorts from Denmark, England, France, Lithuania, the Netherlands, Norway, Italy, Portugal, and Spain. The cohorts included between 2434 and 99 655 pregnancies. The association between maternal education and preterm delivery (22-36 completed weeks...... characteristics. Nevertheless, there were similar educational differences in risk of preterm delivery in 8 of the 12 cohorts with slope index of inequality varying between 2.2 [95% CI 1.1, 3.3] and 4.0 [95% CI 1.4, 6.6] excess preterm deliveries per 100 singleton deliveries among the educationally most......BACKGROUND: An association between education and preterm delivery has been observed in populations across Europe, but differences in methodology limit comparability. We performed a direct cross-cohort comparison of educational disparities in preterm delivery based on individual-level birth cohort...

Central oxygen pipeline failure | Mostert | Southern African Journal ...

African Journals Online (AJOL)

Anaesthetic and critical care staff play a governing role in the comprehension of a hospital's oxygen delivery system and associated contingency plans for internal disaster management. Therefore, staff must be thoroughly prepared and properly trained to support an institution-wide emergency response in the event of ...

Factors determining the choice of a place of delivery among ...

African Journals Online (AJOL)

McRoy

pregnant women in Russia village of Jos North, Nigeria: achieving the ... deliver in the hospital, while 55 (39.3%) opted for home delivery in the index .... index is an indication that poverty is also the ... location from a national survey in India.

Implementing the enterprise master patient index.

Science.gov (United States)

Adragna, L

1998-10-01

In implementing a cross-facility initiative, the importance of planning and understanding the implications for all facilities can't be overlooked. Here's how one integrated delivery network navigated the challenges of implementing a cross-facility enterprise master patient index.

Hyperbaric Oxygen Therapy and Oxygen Compatibility of Skin and Wound Care Products.

Science.gov (United States)

Bernatchez, Stéphanie F; Tucker, Joseph; Chiffoleau, Gwenael

2017-11-01

Objective: Use test methods to assess the oxygen compatibility of various wound care products. Approach: There are currently no standard test methods specifically for evaluating the oxygen compatibility and safety of materials under hyperbaric oxygen (HBO) conditions. However, tests such as the oxygen index (OI), oxygen exposure (OE), and autogenous ignition temperature (AIT) can provide useful information. Results: The OI test measures the minimum oxygen concentration that will support candle-like burning, and it was used to test 44 materials. All but two exhibited an OI equal to or greater (safer) than a control material commonly used in HBO. The OE test exposes each material to an oxygen-enriched atmosphere (>99.5% oxygen) to monitor temperature and pressure for an extended duration. The results of the OE testing indicated that none of the 44 articles tested with this method self-ignited within the 60°C, 3 atm pressurized oxygen atmosphere. The AIT test exposes materials to a rapid ramp up in temperature in HBO conditions at 3 atm until ignition occurs. Ten wound care materials and seven materials usually avoided in HBO chambers were tested. The AIT ranged from 138°C to 384°C for wound care products and from 146°C to 420°C for the other materials. Innovation: This work provides useful data and recommendations to help develop a new standard approach for evaluating the HBO compatibility of wound care products to ensure safety for patients and clinicians. Conclusion: The development of an additional test to measure the risk of electrostatic discharge of materials in HBO conditions is needed.

Coolant Chemistry Control: Oxygen Mass Transport in Lead Bismuth Eutectic

International Nuclear Information System (INIS)

Weisenburger, A.; Mueller, G.; Bruzzese, C.; Glass, A.

2015-01-01

In lead-bismuth cooled transmutation systems, oxygen, dissolved in the coolant at defined quantities, is required for stable long-term operation by assuring the formation of protective oxide scales on structural steel surfaces. Extracted oxygen must be permanently delivered to the system and distributed in the entire core. Therefore, coolant chemistry control involves detailed knowledge on oxygen mass transport. Beside the different flow regimes a core might have stagnant areas at which oxygen delivery can only be realised by diffusion. The difference between oxygen transport in flow paths and in stagnant zones is one of the targets of such experiments. To investigate oxygen mass transport in flowing and stagnant conditions, a dedicated facility was designed based on computational fluid dynamics (CFD). CFD also was applied to define the position of oxygen sensors and ultrasonic Doppler velocimetry transducers for flow measurements. This contribution will present the test facility, design relevant CFD calculations and results of first tests performed. (authors)

Low blood flow at onset of moderate intensity exercise does not limit muscle oxygen uptake

DEFF Research Database (Denmark)

Nyberg, Michael Permin; Mortensen, Stefan Peter; Saltin, Bengt

2010-01-01

The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion of i....... Additionally, prostanoids and/or NO appear to play important roles in elevating skeletal muscle blood flow in the initial phase of exercise. Key words: Oxygen delivery, oxygen extraction, nitric oxide, prostanoids.......The effect of low blood flow at onset of moderate intensity exercise on the rate of rise in muscle oxygen uptake was examined. Seven male subjects performed a 3.5 minute one-legged knee-extensor exercise bout (24+/-1 (+/-S.D.) W) without (CON) and with (double blockade; DB) arterial infusion...... of inhibitors of nitric oxide synthase (NOS; L-NMMA) and cyclooxygenase (COX; indomethacin) in order to inhibit the synthesis of nitric oxide (NO) and prostanoids, respectively.. Leg blood flow and leg oxygen delivery throughout exercise was 25-50 % lower (P

Buccal Transmucosal Delivery System of Enalapril for Improved ...

African Journals Online (AJOL)

Methods: Transmucosal drug delivery systems of enalapril maleate were ... Index Medicus, JournalSeek, Journal Citation Reports/Science Edition, Directory of Open Access Journals. (DOAJ) ... investigated for various drugs including protein.

The 30-second rule: the effects of prolonged intubation attempts on oxygen saturation and heart rate in preterm infants in the delivery room.

Science.gov (United States)

Wozniak, Madeline; Arnell, Kathy; Brown, Melissa; Gonzales, Sarah; Lazarus, Danielle; Rich, Wade; Katheria, Anup

2018-04-01

A duration of 30 seconds has been shown to improve the success rate of intubation attempts without any decompensation. There is limited data regarding the detrimental effects of prolonged intubation attempts in preterm infants. The aim was to determine the effect of prolonged intubation attempts on heart rate and oxygen saturation in preterm infants. We retrospectively reviewed videos and physiologic data collected during delivery room (DR) resuscitations. Infants who had a functioning pulse oximeter at the time of intubation in the delivery room were analyzed using video and analog recordings. The duration of the intubation attempt was defined as the time the laryngoscope blade was in the infant's mouth. Prolonged intubations were defined as intubations over 30 seconds. Baseline heart rate and saturations were defined as the heart rate and saturation immediately prior to the intubation attempt. Video recording was used to determine time laryngoscope was in the mouth, what other procedures were performed, and whether there was recovery between attempts. Analog data including heart rate, airway pressure and saturation was also recorded. There were 52 intubation attempts in 28 infants. The median (IQR) birth weight and gestational age were 795 (705, 972) grams and 25 (25, 27) weeks. The duration of an intubation attempt was 35 (27, 46) seconds with number of attempts 2 (1, 2). There were 34 intubation attempts greater than 30 seconds (prolonged group) and 18 attempts less than or equal to 30 seconds (short group). Longer attempts did not affect intubation success (successful 34 [25,37] seconds vs. unsuccessful 41[29, 53] seconds; P=0.05). Infants in the prolonged group had a greater decrease in oxygen saturation percentage from baseline (5±8 percent, short intubation group and 13±27 prolonged intubation group; P=0.004). There was also a significant decrease in heart rate beats per minute between the two groups (6±9 in the short intubation group and 23±29

Gradually Increased Oxygen Administration Improved Oxygenation and Mitigated Oxidative Stress after Resuscitation from Severe Hemorrhagic Shock.

Science.gov (United States)

Luo, Xin; Yin, Yujing; You, Guoxing; Chen, Gan; Wang, Ying; Zhao, Jingxiang; Wang, Bo; Zhao, Lian; Zhou, Hong

2015-11-01

The optimal oxygen administration strategy during resuscitation from hemorrhagic shock (HS) is still controversial. Improving oxygenation and mitigating oxidative stress simultaneously seem to be contradictory goals. To maximize oxygen delivery while minimizing oxidative damage, the authors proposed the notion of gradually increased oxygen administration (GIOA), which entails making the arterial blood hypoxemic early in resuscitation and subsequently gradually increasing to hyperoxic, and compared its effects with normoxic resuscitation, hyperoxic resuscitation, and hypoxemic resuscitation in severe HS. Rats were subjected to HS, and on resuscitation, the rats were randomly assigned to four groups (n = 8): the normoxic, the hyperoxic, the hypoxemic, and the GIOA groups. Rats were observed for an additional 1 h. Hemodynamics, acid-base status, oxygenation, and oxidative injury were observed and evaluated. Central venous oxygen saturation promptly recovered only in the hyperoxic and the GIOA groups, and the liver tissue partial pressure of oxygen was highest in the GIOA group after resuscitation. Oxidative stress in GIOA group was significantly reduced compared with the hyperoxic group as indicated by the reduced malondialdehyde content, increased catalase activity, and the lower histologic injury scores in the liver. In addition, the tumor necrosis factor-α and interleukin-6 expressions in the liver were markedly decreased in the GIOA group than in the hyperoxic and normoxic groups as shown by the immunohistochemical staining. GIOA improved systemic/tissue oxygenation and mitigated oxidative stress simultaneously after resuscitation from severe HS. GIOA may be a promising strategy to improve resuscitation from HS and deserves further investigation.

Children’s Oxygen Administration Strategies Trial (COAST:  A randomised controlled trial of high flow versus oxygen versus control in African children with severe pneumonia [version 2; referees: 2 approved

Directory of Open Access Journals (Sweden)

Kathryn Maitland

2018-01-01

Full Text Available Background: In Africa, the clinical syndrome of pneumonia remains the leading cause of morbidity and mortality in children in the post-neonatal period. This represents a significant burden on in-patient services. The targeted use of oxygen and simple, non-invasive methods of respiratory support may be a highly cost-effective means of improving outcome, but the optimal oxygen saturation threshold that results in benefit and the best strategy for delivery are yet to be tested in adequately powered randomised controlled trials. There is, however, an accumulating literature about the harms of oxygen therapy across a range of acute and emergency situations that have stimulated a number of trials investigating permissive hypoxia. Methods: In 4200 African children, aged 2 months to 12 years, presenting to 5 hospitals in East Africa with respiratory distress and hypoxia (oxygen saturation or = 80% (permissive hypoxia; and High flow using AIrVO2TM compared with low flow delivery (routine care. Discussion: The overarching objective is to address the key research gaps in the therapeutic use of oxygen in resource-limited setting in order to provide a better evidence base for future management guidelines. The trial has been designed to address the poor outcomes of children in sub-Saharan Africa, which are associated with high rates of in-hospital mortality, 9-10% (for those with oxygen saturations of 80-92% and 26-30% case fatality for those with oxygen saturations <80%. Clinical trial registration: ISRCTN15622505 Trial status: Recruiting

A simplified concept for controlling oxygen mixtures in the anaesthetic machine--better, cheaper and more user-friendly?

Science.gov (United States)

Berge, J A; Gramstad, L; Grimnes, S

1995-05-01

Modern anaesthetic machines are equipped with several safety components to prevent delivery of hypoxic mixtures. However, such a technical development has increased the complexity of the equipment. We report a reconstructed anaesthetic machine in which a paramagnetic oxygen analyzer has provided the means to simplify the apparatus. The new machine is devoid of several components conventionally included to prevent hypoxic mixtures: oxygen failure protection device, reservoir O2 alarm, N2O/air selector, and proportioning system for oxygen/nitrous oxide delivery. These devices have been replaced by a simple safety system using a paramagnetic oxygen analyzer at the common gas outlet, which in a feed-back system cuts off the supply of nitrous oxide whenever the oxygen concentration falls below 25%. The simplified construction of the anaesthetic machine has important consequences for safety, cost and user-friendliness. Reducing the complexity of the construction also simplifies the pre-use checkout procedure, and an efficient 5-point check list is presented for the new machine.

The impact of body mass index on the risk of high spinal block in parturients undergoing cesarean delivery: a retrospective cohort study.

Science.gov (United States)

Lamon, Agnes M; Einhorn, Lisa M; Cooter, Mary; Habib, Ashraf S

2017-08-01

To investigate the hypothesis that the risk of high spinal block is not increased in obese parturients undergoing cesarean delivery compared to non-obese parturients. This is a retrospective study at an academic center. We searched the perioperative database for women who underwent cesarean delivery under spinal or combined spinal epidural anesthesia with hyperbaric bupivacaine ≥10.5 mg. A body mass index (BMI) ≥30 kg/m 2 was defined as obese. We categorized obesity into: obesity class I (BMI = 30-34.9 kg/m 2 ), obesity class II (BMI = 35-39.9 kg/m 2 ), obesity class III (BMI = 40-49.9 kg/m 2 ), and super obese (BMI ≥50 kg/m 2 ). The primary outcome was high spinal block defined as need to convert to general anesthesia within 20 min of spinal placement as a result of altered mental status, weakness, or respiratory distress resulting from the high block, or a recorded block height ≥T1. The analysis included 5015 women. High spinal blocks occurred in 29 patients (0.6%). The risk of high spinal was significantly different according to BMI (p = 0.025). In a multivariate model, BMI (p = 0.008) and cesarean delivery priority (p = 0.009) were associated with high blocks. BMI ≥50 kg/m 2 was associated with greater odds of high block compared to BMI block compared with unscheduled delivery. At standard spinal doses of hyperbaric bupivacaine used in our practice (≥10.5 mg), there were greater odds of high block in those with BMI ≥50 kg/m 2 .

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.

[Role of erythrocyte cytoplasmic structures in changes in the affinity of haemoglobin for oxygen].

Science.gov (United States)

Bryzgalova, N Iu; Brazhe, N A; Iusipovich, A U; Maksimov, G V; Rubin, A B

2009-01-01

Changes in the refractive index of the cytoplasm and the affinity of haemoporphyrin of erythrocyte haemoglobin to oxygen (pH, 2,3-diphosphoglycerate) have been investigated using laser interference microscopy and Raman spectroscopy. It has been established that a decrease in pH and an increase in the content of 2,3-diphosphoglycerate are accompanied by changes in both the form of the cell and the refractive index of the cytoplasm and the affinity of haemoporphyrin of hemoglobin to oxygen. It has been shown that as pH is reduced, the capacity of haemoporphyrin for binding oxygen decreases and as the concentration of 2,3-diphosphoglycerate is increased, the ability of haemoporphyrin for oxygen reabsorption increases.

Studies on the rheology and oxygen mass transfer in the clavulanic acid production by Streptomyces clavuligerus

Directory of Open Access Journals (Sweden)

E. R. Gouveia

2000-12-01

Full Text Available In the present work rheological characteristics and volumetric oxygen transfer coefficient (kLa were investigated during batch cultivations of Streptomyces clavuligerus NRRL 3585 for production of clavulanic acid. The experimental rheological data could be adequately described in terms of the power law model and logistic equation. Significant changes in the rheological parameters consistency index (K and flow behavior index (n were observed with the fermentation evolution. Interesting correlations between the consistency index (K/biomass concentration (C X and the flow behavior index (n/biomass concentration were proposed. Volumetric oxygen mass transfer coefficient (kLa was determined by the gas balance method. Classical correlation relating the volumetric oxygen mass transfer coefficient to the operating conditions, physical and to transport properties, including apparent viscosity (muap, could be applied to the experimental results.

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．

The real limits to marine life: a further critique of the Respiration Index

Science.gov (United States)

Seibel, B. A.; Childress, J. J.

2013-05-01

The recently proposed "Respiration Index" (RI = log PO2/PCO2) suggests that aerobic metabolism is limited by the ratio of reactants (oxygen) to products (carbon dioxide) according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = -686 kcal mol-1), carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503), where ΔG = 0. Thus, a Respiration Index of -503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

The real limits to marine life: a further critique of the Respiration Index

Directory of Open Access Journals (Sweden)

B. A. Seibel

2013-05-01

Full Text Available The recently proposed "Respiration Index" (RI = log PO2/PCO2 suggests that aerobic metabolism is limited by the ratio of reactants (oxygen to products (carbon dioxide according to the thermodynamics of cellular respiration. Here, we demonstrate further that, because of the large standard free energy change for organic carbon oxidation (ΔG° = −686 kcal mol−1, carbon dioxide can never reach concentrations that would limit the thermodynamics of this reaction. A PCO2 to PO2 ratio of 10503 would be required to reach equilibrium (equilibrium constant, Keq = 10503, where ΔG = 0. Thus, a Respiration Index of −503 would be the real thermodynamic limit to aerobic life. Such a Respiration Index is never reached, either in the cell or in the environment. Moreover, cellular respiration and oxygen provision are kinetically controlled such that, within limits, environmental oxygen and CO2 concentrations have little to do with intracellular concentrations. The RI is fundamentally different from the aragonite saturation state, a thermodynamic index used to quantify the potential effect of CO2 on calcification rates, because of its failure to incorporate the equilibrium constant of the reaction. Not only is the RI invalid, but its use leads to incorrect and misleading predictions of the threat of changing oxygen and carbon dioxide to marine life. We provide a physiological framework that identifies oxygen thresholds and allows for synergistic effects of ocean acidification and global warming.

Pulmonary venous flow index as a predictor of pulmonary vascular resistance variability in congenital heart disease with increased pulmonary flow: a comparative study before and after oxygen inhalation.

Science.gov (United States)

Rivera, Ivan Romero; Mendonça, Maria Alayde; Andrade, José Lázaro; Moises, Valdir; Campos, Orlando; Silva, Célia Camelo; Carvalho, Antonio Carlos

2013-09-01

There is no definitive and reliable echocardiographic method for estimating the pulmonary vascular resistance (PVR) to differentiate persistent vascular disease from dynamic pulmonary hypertension. The aim of this study was to analyze the relationship between the pulmonary venous blood flow velocity-time integral (VTIpv) and PVR. Eighteen patients (10 females; 4 months to 22 years of age) with congenital heart disease and left to right shunt were studied. They underwent complete cardiac catheterization, including measurements of the PVR and Qp:Qs ratio, before and after 100% oxygen inhalation. Simultaneous left inferior pulmonary venous flow VTIpv was obtained by Doppler echocardiography. The PVR decreased significantly from 5.0 ± 2.6 W to 2.8 ± 2.2 W (P = 0.0001) with a significant increase in the Qp:Qs ratio, from 3.2 ± 1.4 to 4.9 ± 2.4 (P = 0.0008), and the VTIpv increased significantly from 22.6 ± 4.7 cm to 28.1 ± 6.2 cm (P = 0.0002) after 100% oxygen inhalation. VTIpv correlated well with the PVR and Qp:Qs ratio (r = -0.74 and 0.72, respectively). Diagnostic indexes indicated a sensitivity of 86%, specificity of 75%, accuracy of 83%, a positive predictive value of 92% and a negative predictive value of 60%. The VTIpv correlated well with the PVR. The measurement of this index before and after oxygen inhalation may become a useful noninvasive test for differentiating persistent vascular disease from dynamic and flow-related pulmonary hypertension. © 2013, Wiley Periodicals, Inc.

Exogenous and endogenous angiotensin‐II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow

Science.gov (United States)

Emans, Tonja W.; Janssen, Ben J.; Pinkham, Maximilian I.; Ow, Connie P. C.; Evans, Roger G.; Joles, Jaap A.; Malpas, Simon C.; Krediet, C. T. Paul

2016-01-01

Key points Our understanding of the mechanisms underlying the role of hypoxia in the initiation and progression of renal disease remains rudimentary.We have developed a method that allows wireless measurement of renal tissue oxygen tension in unrestrained rats.This method provides stable and continuous measurements of cortical tissue oxygen tension (PO2) for more than 2 weeks and can reproducibly detect acute changes in cortical oxygenation.Exogenous angiotensin‐II reduced renal cortical tissue PO2 more than equi‐pressor doses of phenylephrine, probably because it reduced renal oxygen delivery more than did phenylephrine.Activation of the endogenous renin–angiotensin system in transgenic Cyp1a1Ren2 rats reduced cortical tissue PO2; in this model renal hypoxia precedes the development of structural pathology and can be reversed acutely by an angiotensin‐II receptor type 1 antagonist.Angiotensin‐II promotes renal hypoxia, which may in turn contribute to its pathological effects during development of chronic kidney disease. Abstract We hypothesised that both exogenous and endogenous angiotensin‐II (AngII) can decrease the partial pressure of oxygen (PO2) in the renal cortex of unrestrained rats, which might in turn contribute to the progression of chronic kidney disease. Rats were instrumented with telemeters equipped with a carbon paste electrode for continuous measurement of renal cortical tissue PO2. The method reproducibly detected acute changes in cortical oxygenation induced by systemic hyperoxia and hypoxia. In conscious rats, renal cortical PO2 was dose‐dependently reduced by intravenous AngII. Reductions in PO2 were significantly greater than those induced by equi‐pressor doses of phenylephrine. In anaesthetised rats, renal oxygen consumption was not affected, and filtration fraction was increased only in the AngII infused animals. Oxygen delivery decreased by 50% after infusion of AngII and renal blood flow (RBF) fell by 3.3 ml min−1

[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

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

Chemisorption of oxygen and subsequent reactions on low index surfaces of β-Mo₂C

DEFF Research Database (Denmark)

Shi, Xue Rong; Wang, Shengguang; Wang, Jianguo

2016-01-01

to the carbon vacancy were identified. We examined the effect of oxygen coverage on the morphology of β-Mo2C by plotting the equilibrium crystal shape. Thermodynamic effect of temperature and reactant or product pressure on the CO/CO2 desorption were investigated. The CO/CO2 desorption is more favorable...... at the saturated oxygen coverage than the low oxygen coverage thermodynamically. The subsequent oxygen diffusion to the carbon vacancy after CO/CO2 desorption may happen depending on the surfaces and oxygen coverage....

Electron Paramagnetic Resonance pO2 Image Tumor Oxygen-Guided Radiation Therapy Optimization.

Science.gov (United States)

Epel, Boris; Maggio, Matt; Pelizzari, Charles; Halpern, Howard J

2017-01-01

Modern standards for radiation treatment do not take into account tumor oxygenation for radiation treatment planning. Strong correlation between tumor oxygenation and radiation treatment success suggests that oxygen-guided radiation therapy (OGRT) may be a promising enhancement of cancer radiation treatment. We have developed an OGRT protocol for rodents. Electron paramagnetic resonance (EPR) imaging is used for recording oxygen maps with high spatial resolution and excellent accuracy better than 1 torr. Radiation is delivered with an animal intensity modulated radiation therapy (IMRT) XRAD225Cx micro-CT/ therapy system. The radiation plan is delivered in two steps. First, a uniform 15% tumor control dose (TCD 15 ) is delivered to the whole tumor. In the second step, an additional booster dose amounting to the difference between TCD 98 and TCD 15 is delivered to radio-resistant, hypoxic tumor regions. Delivery of the booster dose is performed using a multiport conformal beam protocol. For radiation beam shaping we used individual radiation blocks 3D-printed from tungsten infused ABS polymer. Calculation of beam geometry and the production of blocks is performed next to the EPR imager, immediately after oxygen imaging. Preliminary results demonstrate the sub-millimeter precision of the radiation delivery and high dose accuracy. The efficacy of the radiation treatment is currently being tested on syngeneic FSa fibrosarcoma tumors grown in the legs of C3H mice.

Reduced muscle activation during exercise related to brain oxygenation and metabolism in humans

DEFF Research Database (Denmark)

Rasmussen, Peter; Nielsen, Jannie; Overgaard, M

2010-01-01

Maximal exercise may be limited by central fatigue defined as an inability of the central nervous system to fully recruit the involved muscles. This study evaluated whether a reduction in the cerebral oxygen-to-carbohydrate index (OCI) and in the cerebral mitochondrial oxygen tension relate to th...... indicating that reduced cerebral oxygenation may play a role in the development of central fatigue and may be an exercise capacity limiting factor.......Maximal exercise may be limited by central fatigue defined as an inability of the central nervous system to fully recruit the involved muscles. This study evaluated whether a reduction in the cerebral oxygen-to-carbohydrate index (OCI) and in the cerebral mitochondrial oxygen tension relate...... of perceived exertion (RPE), arm maximal voluntary force (MVC), and voluntary activation of elbow flexor muscles assessed with transcranial magnetic stimulation. Low intensity exercise did not produce any indication of central fatigue or marked cerebral metabolic deviations. Exercise in hypoxia (0.10) reduced...

Reproducibility of proximal and distal transcutaneous oxygen pressure measurements during exercise in stage 2 arterial claudication.

Science.gov (United States)

Bouyé, P; Picquet, J; Jaquinandi, V; Enon, B; Leftheriotis, G; Saumet, J-L; Abraham, P

2004-06-01

Although transcutaneous oxygen pressure measurements (tcpO2) are largely used in the investigation of vascular patients, its reproducibility is still debated. Indeed an unpredictable gradient exists between arterial and transcutaneous oxygen pressure. We hypothesised that indices taking into account changes over time and independent of absolute starting values would be more reproducible than other indices. comparative test-retest procedure (1 to 13 days between tests). institutional practice, ambulatory care. 15 subjects with stage 2 claudication. tcpO2 recordings at rest and at exercise during the 2 treadmill tests. calculation of the Delta-from-rest of oxygen pressure index (limb tcpO2 changes minus chest tcpO2 changes), of the resting - or minimal values attained during exercise - of absolute tcpO2 and of the regional perfusion index (regional perfusion index: ration of limb to chest). Both absolute tcpO2 and regional perfusion index at rest showed low reproducibility. During exercise the best reproducibility was attained through Delta-from-rest of oxygen pressure index calculation. Equations from the linear regression analysis (test 2 versus test 1) were 0.88 x -4.2 (r(2)=0.82) at the buttock level and 0.82 x -3.8 (r(2)=0.80) at the calf level. TcpO2 measurement on the calf or buttock during exercise, is a reproducible measurement in patients with vascular claudication, specifically when corrected for exercise-induced systemic pO2 changes trough Delta-from-rest of oxygen pressure calculation.

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

Science.gov (United States)

Cabrales, Pedro; Intaglietta, Marcos

2013-01-01

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

Hemodynamic and oxygen transport patterns for outcome prediction, therapeutic goals, and clinical algorithms to improve outcome. Feasibility of artificial intelligence to customize algorithms.

Science.gov (United States)

Shoemaker, W C; Patil, R; Appel, P L; Kram, H B

1992-11-01

A generalized decision tree or clinical algorithm for treatment of high-risk elective surgical patients was developed from a physiologic model based on empirical data. First, a large data bank was used to do the following: (1) describe temporal hemodynamic and oxygen transport patterns that interrelate cardiac, pulmonary, and tissue perfusion functions in survivors and nonsurvivors; (2) define optimal therapeutic goals based on the supranormal oxygen transport values of high-risk postoperative survivors; (3) compare the relative effectiveness of alternative therapies in a wide variety of clinical and physiologic conditions; and (4) to develop criteria for titration of therapy to the endpoints of the supranormal optimal goals using cardiac index (CI), oxygen delivery (DO2), and oxygen consumption (VO2) as proxy outcome measures. Second, a general purpose algorithm was generated from these data and tested in preoperatively randomized clinical trials of high-risk surgical patients. Improved outcome was demonstrated with this generalized algorithm. The concept that the supranormal values represent compensations that have survival value has been corroborated by several other groups. We now propose a unique approach to refine the generalized algorithm to develop customized algorithms and individualized decision analysis for each patient's unique problems. The present article describes a preliminary evaluation of the feasibility of artificial intelligence techniques to accomplish individualized algorithms that may further improve patient care and outcome.

Study on combustion characteristics of dimethyl ether under the moderate or intense low-oxygen dilution condition

International Nuclear Information System (INIS)

Kang, Yinhu; Lu, Tianfeng; Lu, Xiaofeng; Wang, Quanhai; Huang, Xiaomei; Peng, Shini; Yang, Dong; Ji, Xuanyu; Song, Yangfan

2016-01-01

hydroxyl radical concentration inside the reaction zone significantly. Emission index of carbon monoxide increased at lower co-flow temperature or oxygen mole fraction; and it was more sensitive to the variation in co-flow oxygen mole fraction. Additionally, the dominant formation pathways of nitrogen oxide in the dimethyl ether-moderate or intense low-oxygen dilution flame were clarified. The contribution of the thermal pathway was fairly unimportant. Emission index of nitrogen oxide increased as co-flow temperature or oxygen mole fraction was increased. The ratio of nitrogen dioxide emission index to nitrogen oxide emission index decreased with the increment in co-flow temperature or oxygen mole fraction.

Central venous oxygen saturation in septic shock - a marker of cardiac output, microvascular shunting and/or dysoxia?

DEFF Research Database (Denmark)

Haase, Nicolai; Perner, Anders

2011-01-01

Shock therapy aims at increasing central venous oxygen saturation (ScvO2), which is a marker of inadequate oxygen delivery. In this issue of Critical Care, Textoris and colleagues challenge this notion by reporting that high levels of ScvO2 are associated with mortality in patients with septic sh...

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

Milrinone, dobutamine or epinephrine use in asphyxiated newborn pigs resuscitated with 100% oxygen.

Science.gov (United States)

Joynt, Chloë; Bigam, David L; Charrois, Gregory; Jewell, Laurence D; Korbutt, Gregory; Cheung, Po-Yin

2010-06-01

After resuscitation, asphyxiated neonates often develop poor cardiac function with hypotension, pulmonary hypertension and multiorgan ischemia. In a swine model of neonatal hypoxia-reoxygenation, effects of epinephrine, dobutamine and milrinone on systemic, pulmonary and regional hemodynamics and oxygen transport were compared. Controlled, block-randomized study. University research laboratory. Mixed breed piglets (1-3 days, 1.5-2.3 kg). In acutely instrumented piglets, normocapnic alveolar hypoxia (10-15% oxygen) was induced for 2 h followed by reoxygenation with 100% oxygen (1 h) then 21% oxygen (3 h). At 2 h of reoxygenation, after volume loading (Ringer's lactate 10 ml/kg), either saline (placebo), epinephrine (0.5 microg/kg/min), dobutamine (20 microg/kg/min) or milrinone (0.75 microg/kg/min) were infused for 2 h in a blinded, block-randomized fashion (n = 6/group). All medications similarly improved cardiac output, stroke volume and systemic oxygen delivery (vs. placebo-controls, p milrinone maintained, mean arterial pressure over pretreatment values while placebo-treated piglets developed hypotension and shock. The mean arterial to pulmonary arterial pressures ratio was not different among groups. All medications significantly increased carotid and intestinal, but not renal, arterial blood flows and oxygen delivery, whereas milrinone caused lower renal vascular resistance than epinephrine and dobutamine-treated groups. Plasma troponin I, plasma and myocardial lactate levels, and histologic ischemic features were not different among groups. In newborn piglets with hypoxia-reoxygenation, epinephrine, dobutamine and milrinone are effective inotropes to improve cardiac output, carotid and intestinal perfusion, without aggravating pulmonary hypertension. Milrinone may also improve renal perfusion.

Ketamine has no effect on oxygenation indices following elective coronary artery bypass grafting under cardiopulmonary bypass

Directory of Open Access Journals (Sweden)

Parthasarathi Gayatri

2011-01-01

Full Text Available Cardiopulmonary bypass is known to elicit systemic inflammatory response syndrome and organ dysfunction. This can result in pulmonary dysfunction and deterioration of oxygenation after cardiac surgery and cardiopulmonary bypass. Previous studies have reported varying results on anti-inflammatory strategies and oxygenation after cardiopulmonary bypass. Ketamine administered as a single dose at induction has been shown to reduce the pro-inflammatory serum markers in patients undergoing cardiopulmonary bypass. Therefore we investigated if ketamine can result in better oxygenation in these patients. This was a prospective randomized blinded study. Eighty consecutive adult patients undergoing elective coronary artery bypass grafting under cardiopulmonary bypass were included in the study. Patients were divided into two groups. Patients in ketamine group received 1mg/kg of ketamine intravenously at induction of anesthesia. Control group patients received an equal volume of saline. All patients received standard anesthesia, operative and postoperative care.Paired t test and independent sample t test were used to compare the inter-group and between group oxygenation indices respectively. Oxygenation index and duration of ventilation were analyzed. Deterioration of oxygenation index was noted in both the groups after cardiopulmonary bypass. However, there was no significant difference in the oxygenation index at various time points after cardiopulmonary bypass or the duration of ventilation between the two groups. This study shows that the administered as a single dose at induction does not result in better oxygenation after cardiopulmonary bypass.

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

Exogenous and endogenous angiotensin-II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow.

Science.gov (United States)

Emans, Tonja W; Janssen, Ben J; Pinkham, Maximilian I; Ow, Connie P C; Evans, Roger G; Joles, Jaap A; Malpas, Simon C; Krediet, C T Paul; Koeners, Maarten P

2016-11-01

Our understanding of the mechanisms underlying the role of hypoxia in the initiation and progression of renal disease remains rudimentary. We have developed a method that allows wireless measurement of renal tissue oxygen tension in unrestrained rats. This method provides stable and continuous measurements of cortical tissue oxygen tension (PO2) for more than 2 weeks and can reproducibly detect acute changes in cortical oxygenation. Exogenous angiotensin-II reduced renal cortical tissue PO2 more than equi-pressor doses of phenylephrine, probably because it reduced renal oxygen delivery more than did phenylephrine. Activation of the endogenous renin-angiotensin system in transgenic Cyp1a1Ren2 rats reduced cortical tissue PO2; in this model renal hypoxia precedes the development of structural pathology and can be reversed acutely by an angiotensin-II receptor type 1 antagonist. Angiotensin-II promotes renal hypoxia, which may in turn contribute to its pathological effects during development of chronic kidney disease. We hypothesised that both exogenous and endogenous angiotensin-II (AngII) can decrease the partial pressure of oxygen (PO2) in the renal cortex of unrestrained rats, which might in turn contribute to the progression of chronic kidney disease. Rats were instrumented with telemeters equipped with a carbon paste electrode for continuous measurement of renal cortical tissue PO2. The method reproducibly detected acute changes in cortical oxygenation induced by systemic hyperoxia and hypoxia. In conscious rats, renal cortical PO2 was dose-dependently reduced by intravenous AngII. Reductions in PO2 were significantly greater than those induced by equi-pressor doses of phenylephrine. In anaesthetised rats, renal oxygen consumption was not affected, and filtration fraction was increased only in the AngII infused animals. Oxygen delivery decreased by 50% after infusion of AngII and renal blood flow (RBF) fell by 3.3 ml min -1 . Equi-pressor infusion of

Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

Energy Technology Data Exchange (ETDEWEB)

Kim, Songkil; Henry, Mathias [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Fedorov, Andrei G., E-mail: agf@gatech.edu [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

2015-12-07

We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon “halo” deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations.

Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

International Nuclear Information System (INIS)

Kim, Songkil; Henry, Mathias; Fedorov, Andrei G.

2015-01-01

We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon “halo” deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations

Using an energized oxygen micro-jet for improved graphene etching by focused electron beam

Science.gov (United States)

Kim, Songkil; Henry, Mathias; Fedorov, Andrei G.

2015-12-01

We report on an improved Focused Electron Beam Induced Etching (FEBIE) process, which exploits heated oxygen delivery via a continuous supersonic micro-jet resulting in faster graphene patterning and better etch feature definition. Positioning a micro-jet in close proximity to a graphene surface with minimal jet spreading due to a continuous regime of gas flow at the exit of the 10 μm inner diameter capillary allows for focused exposure of the surface to reactive oxygen at high mass flux and impingement energy of a supersonic gas stream localized to a small etching area exposed to electron beam. These unique benefits of focused supersonic oxygen delivery to the surface enable a dramatic increase in the etch rate of graphene with no parasitic carbon "halo" deposition due to secondary electrons from backscattered electrons (BSE) in the area surrounding the etched regions. Increase of jet temperature via local nozzle heating provides means for enhancing kinetic energy of impinging oxygen molecules, which further speed up the etch, thus minimizing the beam exposure time and required electron dose, before parasitic carbon film deposition due to BSE mediated decomposition of adsorbed hydrocarbon contaminants has a measurable impact on quality of graphene etched features. Interplay of different physical mechanisms underlying an oxygen micro-jet assisted FEBIE process is discussed with support from experimental observations.

Auditing Information System : Delivery Product Service

Directory of Open Access Journals (Sweden)

Purwoko Purwoko

2011-05-01

Full Text Available Purpose of the research is to ensure the securities of information system asset and to ensure if informa-tion system support the operational and data collected was valid. Research method that used in this research were library studies and field studies. Field studies such an observation, questioner, and inter-view. the expected result are founding the weakness of security management control, operational man-agement control, input control, and output control of risk happened in the company. Conclusion of this research are the system on the company work good and there’s no potential risk happened and make an impact to the delivery process of information system.Index Terms - Auditing Information system, Delivery product process.

Flexible biodegradable citrate-based polymeric step-index optical fiber.

Science.gov (United States)

Shan, Dingying; Zhang, Chenji; Kalaba, Surge; Mehta, Nikhil; Kim, Gloria B; Liu, Zhiwen; Yang, Jian

2017-10-01

Implanting fiber optical waveguides into tissue or organs for light delivery and collection is among the most effective ways to overcome the issue of tissue turbidity, a long-standing obstacle for biomedical optical technologies. Here, we report a citrate-based material platform with engineerable opto-mechano-biological properties and demonstrate a new type of biodegradable, biocompatible, and low-loss step-index optical fiber for organ-scale light delivery and collection. By leveraging the rich designability and processibility of citrate-based biodegradable polymers, two exemplary biodegradable elastomers with a fine refractive index difference and yet matched mechanical properties and biodegradation profiles were developed. Furthermore, we developed a two-step fabrication method to fabricate flexible and low-loss (0.4 db/cm) optical fibers, and performed systematic characterizations to study optical, spectroscopic, mechanical, and biodegradable properties. In addition, we demonstrated the proof of concept of image transmission through the citrate-based polymeric optical fibers and conducted in vivo deep tissue light delivery and fluorescence sensing in a Sprague-Dawley (SD) rat, laying the groundwork for realizing future implantable devices for long-term implantation where deep-tissue light delivery, sensing and imaging are desired, such as cell, tissue, and scaffold imaging in regenerative medicine and in vivo optogenetic stimulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modeling and experimental methods to predict oxygen distribution in bone defects following cell transplantation.

Science.gov (United States)

Heylman, Christopher M; Santoso, Sharon; Krebs, Melissa D; Saidel, Gerald M; Alsberg, Eben; Muschler, George F

2014-04-01

We have developed a mathematical model that allows simulation of oxygen distribution in a bone defect as a tool to explore the likely effects of local changes in cell concentration, defect size or geometry, local oxygen delivery with oxygen-generating biomaterials (OGBs), and changes in the rate of oxygen consumption by cells within a defect. Experimental data for the oxygen release rate from an OGB and the oxygen consumption rate of a transplanted cell population are incorporated into the model. With these data, model simulations allow prediction of spatiotemporal oxygen concentration within a given defect and the sensitivity of oxygen tension to changes in critical variables. This information may help to minimize the number of experiments in animal models that determine the optimal combinations of cells, scaffolds, and OGBs in the design of current and future bone regeneration strategies. Bone marrow-derived nucleated cell data suggest that oxygen consumption is dependent on oxygen concentration. OGB oxygen release is shown to be a time-dependent function that must be measured for accurate simulation. Simulations quantify the dependency of oxygen gradients in an avascular defect on cell concentration, cell oxygen consumption rate, OGB oxygen generation rate, and OGB geometry.

[Pregnancy toxemia. Oxygen input/extraction in preeclampsia-eclampsia].

Science.gov (United States)

Rodríguez-Badillo, R F; Noriega-R, T; Audifred-Salomón, J R; García-Lara, E

1996-07-01

We tried to determine if the toxemia of pregnancy has during its clinical evolution a dependent DO2/VO2 relationship and determine its critical DO2 and finally define if this has a prognostic value. There were included patients with diagnosis of preeclampsia/eclampsia that were enter at the Intensive Care Unit for treatment and monitoring. It was placed a catheter in the pulmonary artery and it was determine the cardiac output and by means of standard formulas the DO2, VO2 and EO2 were calculated. The critical delivery of oxygen was stablished in agree at the Gutiérrez's method. At the same time it was monitorised the base excess which was gotten from arterial and venous blood gases. 36 patients (29 with preclampsia and 7 with eclampsia) were included, with a mean age of 26.3 years old. The mean gestational age was 36.1 weeks. The critical delivery for preeclamptic patients was stablished in 924 mL/min and at the eclamptic patients in 830 mL/min: both values had prognostic correlation with survival and nonsurvival patients (p 30%. The toxemia of pregnancy had a behaviour like state accompaniment of a dependent DO2/VO2 relationship causing an important oxygen deficient that was improved was improved in the survival patients that reach values over the critical delivery. These facts suggesting the presence of a metabolic blockade in variable degree that can improve or increase agree a therapeutic manipulations in the critic DO2.

A retrospective comparison of VLBW outcomes before and after implementing new delivery room guidelines at a regional tertiary care center.

Science.gov (United States)

Wlodaver, A; Blunt, M; Satnes, K; Escobedo, M; Hallford, G; Szyld, E

2016-03-01

To evaluate the impact of implemented protocol changes on delivery room interventions and very low birth weight (VLBW) health outcomes. Retrospective study comparing birth characteristics, interventions and health outcomes of VLBW infants born in a tertiary care center before (calendar years 2008 to 2009) and after (calendar years 2012 to 2013) implementing new protocols using Chi-square analyses. Four hundred and nine were born before and 303 after changes were implemented. Postimplementation infants had more use of antenatal steroids (P=0.02), gestational age ⩽24 weeks (P=0.03) and birth weights between 501 and 750 g (P=0.04) and less oxygen administration (P=0.002), face mask ventilation (P=0.0001), surfactant use (P=0.0001), chest compressions (P=0.0001), intubation (P=0.002), epinephrine use (P=0.011), hypothermia (P=0.0001) and discharges home on supplemental oxygen (P=0.05). Changes creating a new delivery team, adopting new delivery practice guidelines and updating delivery room equipment resulted in positive outcomes for delivery room practices and patient outcomes.

The risk of emergency cesarean section after failure of vaginal delivery according to prepregnancy body mass index or gestational weight gain by the 2009 Institute of Medicine guidelines

Science.gov (United States)

Kwon, Ha Yan; Kwon, Ja-Young; Park, Yong Won

2016-01-01

Objective To evaluate the risk of emergency cesarean section according to the prepregnancy body mass index (BMI) and gestational weight gain per the 2009 Institute of Medicine guidelines. Methods A retrospective analysis of data from 2,765 women with singleton full-term births (2009 to 2012) who attempted a vaginal delivery was conducted. Pregnancies with preeclampsia, chronic hypertension, diabetes, planned cesarean section, placenta previa, or cesarean section due to fetal anomalies or intrauterine growth restriction were excluded. Odds ratios (ORs) and confidence intervals (CIs) for emergency cesarean section were calculated after adjusting for prepregnancy BMI or gestational weight gain. Results Three-hundred and fifty nine (13.0%) women underwent emergency cesarean section. The adjusted OR for overweight, obese, and extremely obese women indicated a significantly increased risk of cesarean delivery. Gestational weight gain by Institute of Medicine guidelines was not associated with an increased risk of cesarean delivery. However, inadequate and excessive weight gain in obese women was highly associated with an increased risk of emergency cesarean section, compared to these in normal BMI (OR, 5.56; 95% CI, 1.36 to 22.72; OR, 3.63; 95% CI, 1.05 to 12.54; respectively), while there was no significant difference between normal BMI and obese women with adequate weight gain. Conclusion Obese women should be provided special advice before and during pregnancy for controlling weight and careful consideration should be needed at the time of vaginal delivery to avoid emergency cesarean section. PMID:27200306

High Flow Nasal Cannula Oxygen Therapy can be used safely in the general paediatric ward using Paediatric Early Warning Scores

NARCIS (Netherlands)

Morsing, IE; Tinnevelt, Marcel; Jansen, Nicolaas J.G.; Koomen, E

2015-01-01

High Flow Nasal Cannula oxygen therapy (HFNC) is nowadays widely used at paediatric intensive care units (PICU) to provide a safe and comfortable (warm and humidified) oxygen delivery in children with respiratory distress. At general paediatric wards HFNC is hardly used because intensive observation

Oxygen supply in aquatic ectotherms: partial pressure and solubility together explain biodiversity and size patterns.

Science.gov (United States)

Verberk, Wilco C E P; Bilton, David T; Calosi, Piero; Spicer, John I

2011-08-01

Aquatic ectotherms face the continuous challenge of capturing sufficient oxygen from their environment as the diffusion rate of oxygen in water is 3 x 10(5) times lower than in air. Despite the recognized importance of oxygen in shaping aquatic communities, consensus on what drives environmental oxygen availability is lacking. Physiologists emphasize oxygen partial pressure, while ecologists emphasize oxygen solubility, traditionally expressing oxygen in terms of concentrations. To resolve the question of whether partial pressure or solubility limits oxygen supply in nature, we return to first principles and derive an index of oxygen supply from Fick's classic first law of diffusion. This oxygen supply index (OSI) incorporates both partial pressure and solubility. Our OSI successfully explains published patterns in body size and species across environmental clines linked to differences in oxygen partial pressure (altitude, organic pollution) or oxygen solubility (temperature and salinity). Moreover, the OSI was more accurately and consistently related to these ecological patterns than other measures of oxygen (oxygen saturation, dissolved oxygen concentration, biochemical oxygen demand concentrations) and similarly outperformed temperature and altitude, which covaried with these environmental clines. Intriguingly, by incorporating gas diffusion rates, it becomes clear that actually more oxygen is available to an organism in warmer habitats where lower oxygen concentrations would suggest the reverse. Under our model, the observed reductions in aerobic performance in warmer habitats do not arise from lower oxygen concentrations, but instead through organismal oxygen demand exceeding supply. This reappraisal of how organismal thermal physiology and oxygen demands together shape aerobic performance in aquatic ectotherms and the new insight of how these components change with temperature have broad implications for predicting the responses of aquatic communities to

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.

Manipulation of tumor oxygenation and radiosensitivity through modification of cell respiration. A critical review of approaches and imaging biomarkers for therapeutic guidance.

Science.gov (United States)

Gallez, Bernard; Neveu, Marie-Aline; Danhier, Pierre; Jordan, Bénédicte F

2017-08-01

Tumor hypoxia has long been considered as a detrimental factor for the response to irradiation. In order to improve the sensitivity of tumors cells to radiation therapy, tumor hypoxia may theoretically be alleviated by increasing the oxygen delivery or by decreasing the oxygen consumption by tumor cells. Mathematical modelling suggested that decreasing the oxygen consumption should be more efficient than increasing oxygen delivery in order to alleviate tumor hypoxia. In this paper, we review several promising strategies targeting the mitochondrial respiration for which alleviation of tumor hypoxia and increase in sensitivity to irradiation have been demonstrated. Because the translation of these approaches into the clinical arena requires the use of pharmacodynamics biomarkers able to identify shift in oxygen consumption and tumor oxygenation, we also discuss the relative merits of imaging biomarkers (Positron Emission Tomography and Magnetic Resonance) that may be used for therapeutic guidance. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantifying the correlation between spatially defined oxygen gradients and cell fate in an engineered three-dimensional culture model

OpenAIRE

Ardakani, Amir G.; Cheema, Umber; Brown, Robert A.; Shipley, Rebecca J.

2014-01-01

A challenge in three-dimensional tissue culture remains the lack of quantitative information linking nutrient delivery and cellular distribution. Both in vivo and in vitro, oxygen is delivered by diffusion from its source (blood vessel or the construct margins). The oxygen level at a defined distance from its source depends critically on the balance of diffusion and cellular metabolism. Cells may respond to this oxygen environment through proliferation, death and chemotaxis, resulting in spat...

Connecting drug delivery reality to smart materials design.

Science.gov (United States)

Grainger, David W

2013-09-15

Inflated claims to both design and mechanistic novelty in drug delivery and imaging systems, including most nanotechnologies, are not supported by the generally poor translation of these systems to clinical efficacy. The "form begets function" design paradigm is seductive but perhaps over-simplistic in translation to pharmaceutical efficacy. Most innovations show few clinically important distinctions in their therapeutic benefits in relevant preclinical disease and delivery models, despite frequent claims to the contrary. Long-standing challenges in drug delivery issues must enlist more realistic, back-to-basics approaches to address fundamental materials properties in complex biological systems, preclinical test beds, and analytical methods to more reliably determine fundamental pharmaceutical figures of merit, including drug carrier purity and batch-batch variability, agent biodistribution, therapeutic index (safety), and efficacy. Copyright © 2013 Elsevier B.V. All rights reserved.

Postvaginal Delivery Caecal Volvulus and Perforation

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M. M. Abdullah Agha

2012-01-01

Full Text Available Intestinal obstruction is an uncommon complication of pregnancy and pueperium. It has different etiologies and voluvlus is one of the common causes. High index of suspicion is needed to diagnose it as initial presentation is nonspecific and that is critical to avoid adverse outcomes. We presented here one of these cases that followed vaginal delivery and ended with caecal perforation and hemicolectomy.

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.

The Effect of Mode of Delivery on Postpartum Sexual Functioning in Primiparous Women

Directory of Open Access Journals (Sweden)

Fatemeh Dabiri

2014-07-01

Full Text Available Objective: To evaluate the effect of mode of delivery on postpartum sexual functioning in primiparous women. Methods: In this cross-sectional descriptive study, 150 primiparous women in postpartum period, who attended the family planning or vaccination clinics, were enrolled for the study. Eighty-one had vaginal delivery with episiotomy and 69 had experienced cesarean section. Sexual function was evaluated by the Female Sexual Function Index within 3 and 6 months postpartum. Results: About 29% in vaginal delivery group and 37% in cesarean delivery group had resumed their sexual intercourses four weeks after delivery (p=0.280.There were no significant differences between mode of delivery and sexual functioning, including desire, arousal, lubrication, orgasm, satisfaction and pain. Conclusion: The present study showed that postpartum sexual functioning was not associated with the type of delivery.

Development of high power chemical oxygen lodine laser

Energy Technology Data Exchange (ETDEWEB)

Kim, Cheol Jung; Choi, Y. D.; Chung, C. M.; Kim, M. S.; Baik, S. H.; Kwon, S. O.; Park, S. K.; Kim, T. S

2001-10-01

This project is directed to construct 10kW Chemical Oxygen Iodine Laser (COIL) for decommissioning of old nuclear facilities, and to get the key technology that can be used for the development of high energy laser weapon. COIL is possible up to MW class in proportion to the amount of chemical reaction. For this reason, high energy laser weapon including Airborne Laser (ABL) and Airborne Tactical Laser (ATL) has been developed as a military use in USA. Recently, many research group have been doing a development study of COIL for nuclear and industrial use in material processing such as cutting and decommissioning by combining laser beam delivery through optical fiber. The Chemical Oxygen Iodine Laser of 6 kW output power has been developed in this project. The main technologies of chemical reaction and supersonic fluid control were developed. This technology can be applied for construction of 10 kW laser system. This laser can be used for old nuclear facilities and heavy industry by combining laser beam delivery through optical fiber. The development of High Energy Laser (HEL) weapon is necessary as a military use, and we conclude that Airborne Tactical Laser should be developed in our country.

Water quality index for Al-Gharraf River, southern Iraq

Directory of Open Access Journals (Sweden)

Salam Hussein Ewaid

2017-06-01

Full Text Available The Water Quality Index has been developed mathematically to evaluate the water quality of Al-Gharraf River, the main branch of the Tigris River in the south of Iraq. Water samples were collected monthly from five sampling stations during 2015–2016, and 11 parameters were analyzed: biological oxygen demand, total dissolved solids, the concentration of hydrogen ions, dissolved oxygen, turbidity, phosphates, nitrates, chlorides, as well as turbidity, total hardness, electrical conductivity and alkalinity. The index classified the river water, without including turbidity as a parameter, as good for drinking at the first station, poor at stations 2, 3, 4 and very poor at station 5. When turbidity was included, the index classified the river water as unsuitable for drinking purposes in the entire river. The study highlights the importance of applying the water quality indices which indicate the total effect of the ecological factors on surface water quality and which give a simple interpretation of the monitoring data to help local people in improving water quality.

Estimation of maximal oxygen uptake without exercise testing in Korean healthy adult workers.

Science.gov (United States)

Jang, Tae-Won; Park, Shin-Goo; Kim, Hyoung-Ryoul; Kim, Jung-Man; Hong, Young-Seoub; Kim, Byoung-Gwon

2012-08-01

Maximal oxygen uptake is generally accepted as the most valid and reliable index of cardiorespiratory fitness and functional aerobic capacity. The exercise test for measuring maximal oxygen uptake is unsuitable for screening tests in public heath examinations, because of the potential risks of exercise exertion and time demands. We designed this study to determine whether work-related physical activity is a potential predictor of maximal oxygen uptake, and to develop a maximal oxygen uptake equation using a non-exercise regression model for the cardiorespiratory fitness test in Korean adult workers. Study subjects were adult workers of small-sized companies in Korea. Subjects with history of disease such as hypertension, diabetes, asthma and angina were excluded. In total, 217 adult subjects (113 men of 21-55 years old and 104 women of 20-64 years old) were included. Self-report questionnaire survey was conducted on study subjects, and maximal oxygen uptake of each subject was measured with the exercise test. The statistical analysis was carried out to develop an equation for estimating maximal oxygen uptake. The predictors for estimating maximal oxygen uptake included age, gender, body mass index, smoking, leisure-time physical activity and the factors representing work-related physical activity. The work-related physical activity was identified to be a predictor of maximal oxygen uptake. Moreover, the equation showed high validity according to the statistical analysis. The equation for estimating maximal oxygen uptake developed in the present study could be used as a screening test for assessing cardiorespiratory fitness in Korean adult workers.

[Oxidative power and intracellular distribution of mitochondria control cell oxygen regime when arterial hypoxemia occurs].

Science.gov (United States)

Liabakh, E G; Lissov, P N

2012-01-01

The regulatory impact of the mitochondria spatial distribution and enlargement in their oxidative power qO2 on the tissue oxygenation of skeletal muscle during hypoxia were studied. Investigations were performed by the mathematical modeling of 3D O2 diffusion-reaction in muscle fiber. The oxygen consumption rate VO2 and tissue pO2 were analyzed in response to a decrease in arterial blood oxygen concentration from 19.5 to 10 vol. % at a moderate load (3.5 ml/min per 100 g). The cells with evenly (case 1) and unevenly (case 2) distributed mitochondria were considered. According to calculations due to a rise in mitochondria oxidative power from 3.5 to 6.5 ml/min. per 100 g of tissue it is possible to maintain muscle oxygen V(O2) at constant level of 3.5 ml/min per 100 g despite a decrease in O2 delivery. Minimum value of tissue pO2 was about 0 and an area of hypoxia appeared inside the cell in case 1. But hypoxia disappeared and minimum value of pO2 increased from 0 to 4 mm Hg if mitochondria were distributed unevenly (case 2). It is shown that the possibilities of such regulation were limited and depended on the ratio of "the degree of hypoxemia--the level of oxygen delivery." It was assumed that an increase in mitochondria enzyme activity and mitochondria migration to the places of the greatest oxygen consumption rate can improve oxygen regime in the cells in terms of their adaptation to hypoxia. It is possible that changes in mitochondrial oxidative power and their intracellular redistribution may be considered as a new dimension in regulation of cell oxygen regime.

Neonatal and pediatric extracorporeal membrane oxygenation in developing Latin American countries

OpenAIRE

Kattan, Javier; González, Álvaro; Castillo, Andrés; Caneo, Luiz Fernando

2017-01-01

Objective: To review the principles of neonatal‐pediatric extracorporeal membrane oxygenation therapy, prognosis, and its establishment in limited resource‐limited countries in Latino America. Sources: The PubMed database was explored from 1985 up to the present, selecting from highly‐indexed and leading Latin American journals, and Extracorporeal Life Support Organization reports. Summary of the findings: Extracorporeal membrane oxygenation provides “time” for pulmonary and cardiac res...

Project Delivery System Mode Decision Based on Uncertain AHP and Fuzzy Sets

Science.gov (United States)

Kaishan, Liu; Huimin, Li

2017-12-01

The project delivery system mode determines the contract pricing type, project management mode and the risk allocation among all participants. Different project delivery system modes have different characteristics and applicable scope. For the owners, the selection of the delivery mode is the key point to decide whether the project can achieve the expected benefits, it relates to the success or failure of project construction. Under the precondition of comprehensively considering the influence factors of the delivery mode, the model of project delivery system mode decision was set up on the basis of uncertain AHP and fuzzy sets, which can well consider the uncertainty and fuzziness when conducting the index evaluation and weight confirmation, so as to rapidly and effectively identify the most suitable delivery mode according to project characteristics. The effectiveness of the model has been verified via the actual case analysis in order to provide reference for the construction project delivery system mode.

The relationship between pregnancy, preterm and premature delivery

Directory of Open Access Journals (Sweden)

Soleymani-e- Shayesteh Y

2002-06-01

Full Text Available During pregnancy, different froms of periodontal disease such as pregnancy gingivitis, pregnancy tumors, pregnancy stomatitis, may be encountered. But the most considerable point is the pregnant women's infection with periodontal disease and its effect on delivery and weight of newborn infants. Based on the latest researches and statistics, it is concluded that periodontal disease is an important risk factor, leading to preterm or premature delivery. On the other hand, poor hygiene, should be considered as another danger, resulting in premature delivery. Besides, the presence of a collection of oral fosobacteria in ammoniutic fluid in mothers with premature delivery, increases the probability of an oral- haematogenous connection. Moreover, prostaglandin E2, in cervicular fluid, has been considered as an index for periodontal disease activity and loss of weight at the time of birth. These findings suggest that effective steps, to prevent preterm delivery, can be taken, if women, genycologists and dentists have enough knowledge. This article focuses on the special supervision that is required to prevent the effects of hormonal changes on periodontal tissues and conversely to reduce systemic disorders resulting from periodontal disease, in pregnant woman.

Oxygen consumption rates by different oenological tannins in a model wine solution.

Science.gov (United States)

Pascual, Olga; Vignault, Adeline; Gombau, Jordi; Navarro, Maria; Gómez-Alonso, Sergio; García-Romero, Esteban; Canals, Joan Miquel; Hermosín-Gutíerrez, Isidro; Teissedre, Pierre-Louis; Zamora, Fernando

2017-11-01

The kinetics of oxygen consumption by different oenological tannins were measured in a model wine solution using the non-invasive method based on luminiscence. The results indicate that the oxygen consumption rate follows second-order kinetics depending on tannin and oxygen concentrations. They also confirm that the oxygen consumption rate is influenced by temperature in accordance with Arrhenius law. The indications are that ellagitannins are the fastest oxygen consumers of the different oenological tannins, followed in decreasing order by quebracho tannins, skin tannins, seed tannins and finally gallotannins. This methodology can therefore be proposed as an index for determining the effectiveness of different commercial tannins in protecting wines against oxidation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Safe delivery practices: experience from cross-sectional data of Bangladeshi women.

Science.gov (United States)

Kabir, M A; Goh, Kim-Leng; Khan, M M H; Al-Amin, Abul Quasem; Azam, Mohammad Nurul

2015-03-01

This study examines the safe delivery practices of Bangladeshi women using data on 4905 ever-married women aged 15 to 49 years from the 2007 Bangladesh Demographic and Health Survey. Variables that included age, region of origin, education level of respondent and spouse, residence, working status, religion, involvement in NGOs, mass media exposure, and wealth index were analyzed to find correlates of safe delivery practices. More than 80% of the deliveries took place at home, and only 18% were under safe and hygienic conditions. The likelihood of safe deliveries was significantly lower among younger and older mothers than middle-aged mothers and higher among educated mothers and those living in urban areas. Economically better-off mothers and those with greater exposure to mass media had a significantly higher incidence of safe delivery practices. A significant association with religion and safe delivery practices was revealed. Demographic, socioeconomic, cultural, and programmatic factors that are strongly associated with safe delivery practices should be considered in the formulation of reproductive health policy. © 2012 APJPH.

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

International Nuclear Information System (INIS)

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

1987-01-01

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

Elimination of Gaseous Microemboli from Cardiopulmonary Bypass using Hypobaric Oxygenation

Science.gov (United States)

Gipson, Keith E.; Rosinski, David J.; Schonberger, Robert B.; Kubera, Cathryn; Mathew, Eapen S.; Nichols, Frank; Dyckman, William; Courtin, Francois; Sherburne, Bradford; Bordey, Angelique F; Gross, Jeffrey B.

2014-01-01

Background Numerous gaseous microemboli (GME) are delivered into the arterial circulation during cardiopulmonary bypass (CPB). These emboli damage end organs through multiple mechanisms that are thought to contribute to neurocognitive deficits following cardiac surgery. Here, we use hypobaric oxygenation to reduce dissolved gases in blood and greatly reduce GME delivery during CPB. Methods Variable subatmospheric pressures were applied to 100% oxygen sweep gas in standard hollow fiber microporous membrane oxygenators to oxygenate and denitrogenate blood. GME were quantified using ultrasound while air embolism from the surgical field was simulated experimentally. We assessed end organ tissues in swine postoperatively using light microscopy. Results Variable sweep gas pressures allowed reliable oxygenation independent of CO2 removal while denitrogenating arterial blood. Hypobaric oxygenation produced dose-dependent reductions of Doppler signals produced by bolus and continuous GME loads in vitro. Swine were maintained using hypobaric oxygenation for four hours on CPB with no apparent adverse events. Compared with current practice standards of O2/air sweep gas, hypobaric oxygenation reduced GME volumes exiting the oxygenator (by 80%), exiting the arterial filter (95%), and arriving at the aortic cannula (∼100%), indicating progressive reabsorption of emboli throughout the CPB circuit in vivo. Analysis of brain tissue suggested decreased microvascular injury under hypobaric conditions. Conclusions Hypobaric oxygenation is an effective, low-cost, common sense approach that capitalizes on the simple physical makeup of GME to achieve their near-total elimination during CPB. This technique holds great potential for limiting end-organ damage and improving outcomes in a variety of patients undergoing extracorporeal circulation. PMID:24206970

The Role of Oxygen Therapies in Carbon Monoxide Poisoning

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Suleyman Metin

2011-08-01

Full Text Available Due to climate and socio-economic issues in Turkey, the incidence of carbon monoxide (CO poisoning is high, especially in winter. Clinical manifestations may vary depending on the type of CO source, concentration and duration of exposure. The symptoms of CO poisoning predominantly manifest in lots of organs and systems with high oxygen utilization, especially the brain and the heart. The primary aim in oxygen therapy is to eliminate CO and to reduce its toxic effects. In this context, normobaric and hyperbaric oxygen therapy are used to achieve these goals. Normobaric oxygen (NBO treatment is an easily accessible and relatively not expensive modality, where hyperbaric oxygen (HBO therapy requires specific equipment, certified staff and is available only in some centers. Additionally, HBO treatment has several additional advantages over NBO treatment. Despite its benefits, it is compulsory to search for some criteria in selecting patients to be treated because of the limited availability and access of hyperbaric facilities. For an effective evaluation and an optimal treatment, advanced education of the healthcare professionals on the use of oxygen delivery modalities in the management of CO poisoning is imperative. In this review, it has been aimed to outline the significance of oxygen treatment modalities and to determine patient selection criteria for HBO treatment in the management of CO poisoning which continues to be an important threat to community health care. [TAF Prev Med Bull 2011; 10(4.000: 487-494

Ventilation onset prior to umbilical cord clamping (physiological-based cord clamping improves systemic and cerebral oxygenation in preterm lambs.

Directory of Open Access Journals (Sweden)

Graeme R Polglase

Full Text Available As measurement of arterial oxygen saturation (SpO2 is common in the delivery room, target SpO2 ranges allow clinicians to titrate oxygen therapy for preterm infants in order to achieve saturation levels similar to those seen in normal term infants in the first minutes of life. However, the influence of the onset of ventilation and the timing of cord clamping on systemic and cerebral oxygenation is not known.We investigated whether the initiation of ventilation, prior to, or after umbilical cord clamping, altered systemic and cerebral oxygenation in preterm lambs.Systemic and cerebral blood-flows, pressures and peripheral SpO2 and regional cerebral tissue oxygenation (SctO2 were measured continuously in apnoeic preterm lambs (126±1 day gestation. Positive pressure ventilation was initiated either 1 prior to umbilical cord clamping, or 2 after umbilical cord clamping. Lambs were monitored intensively prior to intervention, and for 10 minutes following umbilical cord clamping.Clamping the umbilical cord prior to ventilation resulted in a rapid decrease in SpO2 and SctO2, and an increase in arterial pressure, cerebral blood flow and cerebral oxygen extraction. Ventilation restored oxygenation and haemodynamics by 5-6 minutes. No such disturbances in peripheral or cerebral oxygenation and haemodynamics were observed when ventilation was initiated prior to cord clamping.The establishment of ventilation prior to umbilical cord clamping facilitated a smooth transition to systemic and cerebral oxygenation following birth. SpO2 nomograms may need to be re-evaluated to reflect physiological management of preterm infants in the delivery room.

Reduced cerebral oxygen–carbohydrate index during endotracheal intubation in vascular surgical patients

DEFF Research Database (Denmark)

Fabricius-Bjerre, Andreas; Overgaard, Anders; Winther-Olesen, Marie

2015-01-01

Brain activation reduces balance between cerebral consumption of oxygen versus carbohydrate as expressed by the so-called cerebral oxygen-carbohydrate-index (OCI). We evaluated whether preparation for surgery, anaesthesia including tracheal intubation and surgery affect OCI. In patients undergoing...... aortic surgery, arterial to internal jugular venous (a-v) concentration differences for oxygen versus lactate and glucose were determined from before anaesthesia to when the patient left the recovery room. Intravenous anaesthesia was supplemented with thoracic epidural anaesthesia for open aortic surgery...

The association between weight gain during pregnancy and intertwin delivery weight discordance using 2011-2015 birth registration data from the USA.

Science.gov (United States)

Xiao, Yanni; Shen, Minxue; Ma, Shujuan; Tao, Xuan; Wen, Shi Wu; Tan, Hongzhuan

2018-06-01

To assess the effect of weight gain during pregnancy on intertwin delivery weight discordance. In the present retrospective cohort study using twin delivery records, data were extracted from the 2011-2015 USA birth registration dataset created by the Centers for Disease Control and Prevention. The outcome variable was delivery weight discordance. The nonlinear association of weight gain during pregnancy with delivery weight discordance was examined using a generalized additive model, adjusting for potential confounders. A total of 255 627 twin pairs were included in this analysis. Weight gain during pregnancy showed an inverse, yet nonlinear, association with intertwin delivery weight discordance. Women with weight gain of approximately 25 kg exhibited the lowest level of discordance. When stratified by pre-pregnancy body mass index, the association of weight gain with discordance became insignificant among obese women. When categorizing weight gain according to recommendations from the Institute of Medicine, inadequate weight gain was associated with increased risk of discordance among women of any pre-pregnancy body mass index. Twin pregnancies with maternal weight gain of approximately 25 kg demonstrated the lowest risk of developing intertwin delivery weight discordance, while inadequate weight gain was a risk factor for delivery weight discordance in all pre-pregnancy body mass index categories. © 2018 International Federation of Gynecology and Obstetrics.

SU-E-T-315: Dosimetric Effects of Couch Top Shift On VMAT Delivery in Absence of Indexing

Energy Technology Data Exchange (ETDEWEB)

Islam, M; Jin, H; Ferguson, S; Ahmad, S [Oklahoma Univ. Health Science Ctr., Oklahoma City, OK (United States)

2015-06-15

Purpose: To investigate dosimetric effects of couch top shift for volumetric-modulated arc therapy (VMAT) in absence of indexing of immobilization devices. Methods: A total of twelve VMAT treatment plans were selected from three regions (lung, abdomen, and pelvis) to account for the variation of the patient position relative to the couch top. The treatment plans were generated using the Varian Eclipse system. A pinpoint ionization chamber (PTW TN31014) was placed at the center of 16-cm solid water phantom and the dose was delivered using the Varian TrueBeam STx with BrainLAB ExacTrac couch top. To simulate the day-to-day variation of the patient position relative to couch top, the couch top was laterally shifted up to 50 mm, with an increment of 5 mm from 0 to 20 mm; and of 10 mm afterwards, and the phantom was moved back to 0 cm shift for measurement. The dose was also delivered using a Varian tennis racket grid insert at 0 cm shift to simulate the absence of couch top. The treatment plans were delivered with 6, 10, and 15 MV photons using the same leaf sequencing to investigate the energy dependence of couch top shift. The dose difference was normalized to 0 cm shift for the regular couch top for comparison. Results: The percent difference of dose was found to increase with lateral shift for all energies; however, the average differences were close to 0% and the maximum difference was within 1% along the lateral shifts. The differences with the absence of couch top were 2.2±0.5% (6MV), 1.7±0.3% (10MV), and 1.6±0.2% (15MV), respectively. Conclusion: The inclusion of couch top is recommended in treatment planning to minimize the dosimetric uncertainty between calculated and delivered dose even in absence of indexing of immobilization devices in VMAT delivery.

A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs.

Directory of Open Access Journals (Sweden)

Folco eGiomi

2013-05-01

Full Text Available Heat tolerance in aquatic ectotherms is constrained by a mismatch, occurring at high temperatures, between oxygen delivery and demand which compromises the maintenance of aerobic scope. The present study analyses how the wide thermal tolerance range of an eurythermal model species, the green crab Carcinus maenas is supported and limited by its ability to sustain efficient oxygen transport to tissues. Similar to other eurytherms, C. maenas sustains naturally occurring acute warming events through the integrated response of circulatory and respiratory systems. The response of C. maenas to warming is characterized by two phases. During initial warming, oxygen consumption and heart rate increase while stroke volume and haemolymph oxygen partial pressures decrease. During further warming, dissolved oxygen levels in the venous compartment decrease below the threshold of full haemocyanin oxygen saturation. The progressive release of haemocyanin bound oxygen with further warming follows an exponential pattern, thereby saving energy in oxygen transport and causing an associated leveling off of metabolic rate. According to the concept of oxygen and capacity limited thermal tolerance, this indicates that the thermal tolerance window is widened by the increasing contribution of haemocyanin oxygen transport and associated energy savings in cardiocirculation. Haemocyanin bound oxygen sustains cardiac performance to cover the temperature range experienced by C. maenas in the field. To our knowledge this is the first study providing evidence of a relationship between thermal tolerance and blood (haemolymph oxygen transport in eurythermal invertebrates.

A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs.

Science.gov (United States)

Giomi, Folco; Pörtner, Hans-Otto

2013-01-01

Heat tolerance in aquatic ectotherms is constrained by a mismatch, occurring at high temperatures, between oxygen delivery and demand which compromises the maintenance of aerobic scope. The present study analyses how the wide thermal tolerance range of an eurythermal model species, the green crab Carcinus maenas is supported and limited by its ability to sustain efficient oxygen transport to tissues. Similar to other eurytherms, C. maenas sustains naturally occurring acute warming events through the integrated response of circulatory and respiratory systems. The response of C. maenas to warming can be characterized by two phases. During initial warming, oxygen consumption and heart rate increase, while stroke volume and haemolymph oxygen partial pressure decrease. During further warming, dissolved oxygen levels in the venous compartment decrease below the threshold of full haemocyanin oxygen saturation. The progressive release of haemocyanin bound oxygen with further warming follows an exponential pattern, thereby saving energy in oxygen transport and causing an associated leveling off of metabolic rate. According to the concept of oxygen and capacity limited thermal tolerance (OCLTT), this indicates that the thermal tolerance window is widened by the increasing contribution of haemocyanin oxygen transport and associated energy savings in cardiocirculation. Haemocyanin bound oxygen sustains cardiac performance to cover the temperature range experienced by C. maenas in the field. To our knowledge this is the first study providing evidence of a relationship between thermal tolerance and blood (haemolymph) oxygen transport in a eurythermal invertebrate.

Oxygenation impairment after total arch replacement with a stented elephant trunk for type-A dissection.

Science.gov (United States)

Shen, Yuwen; Liu, Chuanzhen; Fang, Changcun; Xi, Jie; Wu, Shuming; Pang, Xinyan; Song, Guangmin

2018-06-01

To study the risk factors of oxygenation impairment in patients with type-A acute aortic dissection who underwent total arch replacement with a stented elephant trunk. In this study, 169 consecutive patients were enrolled who were diagnosed with type-A acute aortic dissection and underwent a total arch replacement procedure at the Qilu Hospital of Shandong University between January 2015 and February 2017. Postoperative oxygenation impairment was defined as arterial oxygen partial pressure/inspired oxygen fraction ≤ 200 with positive end expiratory pressure ≥ 5 cm H 2 O that occurred within 72 hours of surgery. Perioperative clinical characteristics of all patients were collected and univariable analyses were performed. Risk factors associated with oxygenation impairment identified by univariable analyses were included in the multivariable regression analysis. The incidence of postoperative oxygenation impairment was 48.5%. Postoperative oxygenation impairment was associated with prolonged mechanical ventilation time, intensive care unit stay, and hospital stay. Multivariable regression analysis demonstrated that body mass index (odds ratio [OR], 1.204; 95% confidence interval [CI], 1.065-1.361; P = .003), preoperative oxygenation impairment (OR, 9.768; 95% CI, 4.159-22.941; P impairment. Postoperative oxygenation impairment is a common complication of surgery for type-A acute aortic dissection. Body mass index, preoperative oxygenation impairment, preoperative homocysteine, circulatory arrest time, and plasma transfusion were independent risk factors for oxygenation impairment after a total arch replacement procedure. Copyright © 2018 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

High-Pressure Oxygen Generation for Outpost EVA Study

Science.gov (United States)

Jeng, Frank F.; Conger, Bruce; Ewert, Michael K.; Anderson, Molly S.

2009-01-01

The amount of oxygen consumption for crew extravehicular activity (EVA) in future lunar exploration missions will be significant. Eight technologies to provide high pressure EVA O2 were investigated. They are: high pressure O2 storage, liquid oxygen (LOX) storage followed by vaporization, scavenging LOX from Lander followed by vaporization, LOX delivery followed by sorption compression, water electrolysis followed by compression, stand-alone high pressure water electrolyzer, Environmental Control and Life Support System (ECLSS) and Power Elements sharing a high pressure water electrolyzer, and ECLSS and In-Situ Resource Utilization (ISRU) Elements sharing a high pressure electrolyzer. A trade analysis was conducted comparing launch mass and equivalent system mass (ESM) of the eight technologies in open and closed ECLSS architectures. Technologies considered appropriate for the two architectures were selected and suggested for development.

Dissolved oxygen content as an index of water quality in San Vicente Bay, Chile (36 degrees 45'S).

Science.gov (United States)

Rudolph, Anny; Ahumada, Ramón; Pérez, Claudio

2002-08-01

The present report describes some effects of industrial and municipal effluents on the waters of San Vicente Bay. Analyses of the main substances contained in the fishing industry effluent suggest rating criteria based on the oxygen saturation of the water as an assessment of organic pollution. Six cruises were carried out throughout the Bay, from June to December 1996. Water samples were analyzed for dissolved oxygen, oil and grease content, and sediment samples for organic matter content. Water parameters (salinity, temperature) were used to characterize the Bay's hydrography, and to calculate values for oxygen saturation. The measurements demonstrated a local broad range of oxygen deficit, with a maximum of 45% in the winter to 95% in the spring. In November more than 65% of the Bay's area showed oxygen deficits greater than 40%. Organic matter was unusually high in sediments along the northern sector of the Bay. The results suggest that the oxygen depletion was a representative parameter for establishing a relative scale of water quality in this Bay.

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

The effect of a structured neonatal resuscitation program on delivery room practices.

LENUS (Irish Health Repository)

Ryan, C A

2012-02-03

PURPOSE: This study evaluated the introduction of the Neonatal Resuscitation Program (NRP) of the American Academy of Pediatrics and the American Heart Association into the delivery room of an Irish maternity hospital. DESIGN: Prospective, controlled observational study of 51 deliveries before and 51 deliveries following the training of delivery room personnel in the NRP. SAMPLE: Participants were 33 nurse-midwives and 11 pediatric resident physicians. MAIN OUTCOME VARIABLE: Evaluation of postdelivery, newborn resuscitation practices. RESULTS: The introduction of the NRP was associated with significant improvements in delivery room preparation, in the evaluation and management of the newborn infant, and in thermal protection at birth. Although there was a trend to use more free-flow oxygen following the introduction of the NRP, this was not statistically significant. Bag and mask ventilation was also used more frequently following NRP training. However, there were no significant differences in the use of endotracheal intubation, chest compressions, and medications. Fifteen of the 51 infants became hypothermic prior to the introduction of the NRP; none of the infants developed hypothermia in the post-NRP part of the study.

Oxygen Supplementation to Stabilize Preterm Infants in the Fetal to Neonatal Transition: No Satisfactory Answer.

Science.gov (United States)

Torres-Cuevas, Isabel; Cernada, Maria; Nuñez, Antonio; Escobar, Javier; Kuligowski, Julia; Chafer-Pericas, Consuelo; Vento, Maximo

2016-01-01

Fetal life elapses in a relatively low oxygen environment. Immediately after birth with the initiation of breathing, the lung expands and oxygen availability to tissue rises by twofold, generating a physiologic oxidative stress. However, both lung anatomy and function and the antioxidant defense system do not mature until late in gestation, and therefore, very preterm infants often need respiratory support and oxygen supplementation in the delivery room to achieve postnatal stabilization. Notably, interventions in the first minutes of life can have long-lasting consequences. Recent trials have aimed to assess what initial inspiratory fraction of oxygen and what oxygen targets during this transitional period are best for extremely preterm infants based on the available nomogram. However, oxygen saturation nomogram informs only of term and late preterm infants but not on extremely preterm infants. Therefore, the solution to this conundrum may still have to wait before a satisfactory answer is available.

Effect of strain rate on sooting limits in counterflow diffusion flames of gaseous hydrocarbon fuels: Sooting temperature index and sooting sensitivity index

KAUST Repository

Wang, Yu

2014-05-01

The effect of the strain rate on the sooting limits in counterflow diffusion flames was investigated in various gaseous hydrocarbon fuels by varying the nitrogen dilution in the fuel and oxidizer streams. The sooting limit was defined as the critical fuel and oxygen mole fraction at which soot started to appear in the elastic light scattering signal. The sooting region for normal alkane fuels at a specified strain rate, in terms of the fuel and oxygen mole fraction, expanded as the number of carbon atoms increased. The alkene fuels (ethylene, propene) tested had a higher propensity for sooting as compared with alkane fuels with the same carbon numbers (ethane, propane). Branched iso-butane had a higher propensity for sooting than did n-butane. An increase in the strain rate reduced the tendency for sooting in all the fuels tested. The sensitivity of the sooting limit to the strain rate was more pronounced for less sooting fuels. When plotted in terms of calculated flame temperature, the critical oxygen mole fraction exhibited an Arrhenius form under sooting limit conditions, which can be utilized to significantly reduce the effort required to determine sooting limits at different strain rates. We found that the limiting temperatures of soot formation flames are viable sooting metrics for quantitatively rating the sooting tendency of various fuels, based on comparisons with threshold soot index and normalized smoke point data. We also introduce a sooting temperature index and a sooting sensitivity index, two quantitative measures to describe sooting propensity and its dependence on strain rate. © 2013 The Combustion Institute.

Inhaled nitric oxide augments nitric oxide transport on sickle cell hemoglobin without affecting oxygen affinity

OpenAIRE

Gladwin, Mark T.; Schechter, Alan N.; Shelhamer, James H.; Pannell, Lewis K.; Conway, Deirdre A.; Hrinczenko, Borys W.; Nichols, James S.; Pease-Fye, Margaret E.; Noguchi, Constance T.; Rodgers, Griffin P.; Ognibene, Frederick P.

1999-01-01

Nitric oxide (NO) inhalation has been reported to increase the oxygen affinity of sickle cell erythrocytes. Also, proposed allosteric mechanisms for hemoglobin, based on S-nitrosation of β-chain cysteine 93, raise the possibilty of altering the pathophysiology of sickle cell disease by inhibiting polymerization or by increasing NO delivery to the tissue. We studied the effects of a 2-hour treatment, using varying concentrations of inhaled NO. Oxygen affinity, as measured by P50, did not respo...

Effects of Hemoglobin-Based Oxygen Carriers on Blood Coagulation

Directory of Open Access Journals (Sweden)

Kimia Roghani

2014-12-01

Full Text Available For many decades, Hemoglobin-based oxygen carriers (HBOCs have been central in the development of resuscitation agents that might provide oxygen delivery in addition to simple volume expansion. Since 80% of the world population lives in areas where fresh blood products are not available, the application of these new solutions may prove to be highly beneficial (Kim and Greenburg 2006. Many improvements have been made to earlier generation HBOCs, but various concerns still remain, including coagulopathy, nitric oxide scavenging, platelet interference and decreased calcium concentration secondary to volume expansion (Jahr et al. 2013. This review will summarize the current challenges faced in developing HBOCs that may be used clinically, in order to guide future research efforts in the field.

Can Oxygen Set Thermal Limits in an Insect and Drive Gigantism?

Science.gov (United States)

Verberk, Wilco C. E. P.; Bilton, David T.

2011-01-01

Background Thermal limits may arise through a mismatch between oxygen supply and demand in a range of animal taxa. Whilst this oxygen limitation hypothesis is supported by data from a range of marine fish and invertebrates, its generality remains contentious. In particular, it is unclear whether oxygen limitation determines thermal extremes in tracheated arthropods, where oxygen limitation may be unlikely due to the efficiency and plasticity of tracheal systems in supplying oxygen directly to metabolically active tissues. Although terrestrial taxa with open tracheal systems may not be prone to oxygen limitation, species may be affected during other life-history stages, particularly if these rely on diffusion into closed tracheal systems. Furthermore, a central role for oxygen limitation in insects is envisaged within a parallel line of research focussing on insect gigantism in the late Palaeozoic. Methodology/Principal Findings Here we examine thermal maxima in the aquatic life stages of an insect at normoxia, hypoxia (14 kPa) and hyperoxia (36 kPa). We demonstrate that upper thermal limits do indeed respond to external oxygen supply in the aquatic life stages of the stonefly Dinocras cephalotes, suggesting that the critical thermal limits of such aquatic larvae are set by oxygen limitation. This could result from impeded oxygen delivery, or limited oxygen regulatory capacity, both of which have implications for our understanding of the limits to insect body size and how these are influenced by atmospheric oxygen levels. Conclusions/Significance These findings extend the generality of the hypothesis of oxygen limitation of thermal tolerance, suggest that oxygen constraints on body size may be stronger in aquatic environments, and that oxygen toxicity may have actively selected for gigantism in the aquatic stages of Carboniferous arthropods. PMID:21818347

Can oxygen set thermal limits in an insect and drive gigantism?

Directory of Open Access Journals (Sweden)

Wilco C E P Verberk

Full Text Available BACKGROUND: Thermal limits may arise through a mismatch between oxygen supply and demand in a range of animal taxa. Whilst this oxygen limitation hypothesis is supported by data from a range of marine fish and invertebrates, its generality remains contentious. In particular, it is unclear whether oxygen limitation determines thermal extremes in tracheated arthropods, where oxygen limitation may be unlikely due to the efficiency and plasticity of tracheal systems in supplying oxygen directly to metabolically active tissues. Although terrestrial taxa with open tracheal systems may not be prone to oxygen limitation, species may be affected during other life-history stages, particularly if these rely on diffusion into closed tracheal systems. Furthermore, a central role for oxygen limitation in insects is envisaged within a parallel line of research focussing on insect gigantism in the late Palaeozoic. METHODOLOGY/PRINCIPAL FINDINGS: Here we examine thermal maxima in the aquatic life stages of an insect at normoxia, hypoxia (14 kPa and hyperoxia (36 kPa. We demonstrate that upper thermal limits do indeed respond to external oxygen supply in the aquatic life stages of the stonefly Dinocras cephalotes, suggesting that the critical thermal limits of such aquatic larvae are set by oxygen limitation. This could result from impeded oxygen delivery, or limited oxygen regulatory capacity, both of which have implications for our understanding of the limits to insect body size and how these are influenced by atmospheric oxygen levels. CONCLUSIONS/SIGNIFICANCE: These findings extend the generality of the hypothesis of oxygen limitation of thermal tolerance, suggest that oxygen constraints on body size may be stronger in aquatic environments, and that oxygen toxicity may have actively selected for gigantism in the aquatic stages of Carboniferous arthropods.

Targeted modulation of reactive oxygen species in the vascular endothelium

OpenAIRE

Shuvaev, Vladimir V.; Muzykantov, Vladimir R.

2011-01-01

Endothelial cells lining vascular luminal surface represent an important site of signaling and injurious effects of reactive oxygen species (ROS) produced by other cells and endothelium itself in ischemia, inflammation and other pathological conditions. Targeted delivery of ROS modulating enzymes conjugated with antibodies to endothelial surface molecules (vascular immunotargeting) provides site-specific interventions in the endothelial ROS, unattainable by other formulations including PEG-mo...

[Influence of the delivery on neonatal competence].

Science.gov (United States)

Simion, F; Dondi, M; Ferlini, I; Valenza, E; Zanco, F

1992-01-01

It is a widely held view that the NBAS (Brazelton, 1973) can index differences in the level of the neurobehavioural organization of both pathological and normal newborns. The present study employed the NBAS to determine whether the type of delivery, i.e. cesarean or spontaneous vaginal, can influence the level of neurobehavioural organization in the first days of life. To this aim, two groups of healthy newborns, as assessed through obstetrical anamnesis and the Apgar index, were compared at 4, 24, 72 hours of postnatal life. Ten newborns were born by cesarean section and 10 were born by spontaneous vaginal delivery. The results did not show any neurobehavioural differences for the five clusters of the NBAS: Response decrement, Orientation, Motor, Range and Regulation of states. This outcome fails to support the hypothesis that the level of neurobehavioural organization in the first hours of postnatal life depends on the type of delivery. It must be considered, however, that the null results could be attributed to the way the NBAS is administered according to Brazelton's criteria of "best performance" and "flexibility of the examiner". In essence, these criteria require the NBAS to be administered several times in succession, by varying the order of clusters and the order of items within a cluster, until the "best performance" is obtained. Therefore, a second experiment was conducted, in which the criticisms and suggestions put forward by Prechtl (1982) were taken into account. Two groups of 10 newborns each, selected as before, were tested.(ABSTRACT TRUNCATED AT 250 WORDS)

Water Quality Index in the Vicinity of Pelepah Kanan Mine, Kota Tinggi, Johor

International Nuclear Information System (INIS)

Wan Mohd Razi Idris; Sahibin Abdul Rahim; Mohd Talib Latif; Zulfahmi Ali Rahman; Tukimat Lihan; Chong, L.Y.; Azman Hashim; Shahrinizam Mohd Yusuf

2009-01-01

This study was carried out to determine the water quality index at the Pelepah Kanan River, Kota Tinggi, Johor. Six stations were chosen from different part of the river from upstream to downstream to represent the water quality index along this river. Three replicates of samples were taken from each station. Samples were collected in two different seasons namely dry season (July) and rainy season (December) 2007. In-situ physico-chemical measurements included temperature, ph, dissolved oxygen and conductivity. Physico-chemical parameters determined in the laboratory were turbidity, total suspended solid (TSS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). According to the Interim National Water Quality Standards (INWQS), results showed that all sampling stations along the Pelepah Kanan River in July fall in Class I-II for physical and chemical parameters except for dissolved oxygen and pH which was in Class I-II. The results obtained in December also showed that all sampling stations fall in Class I for physical and chemical parameters except for pH which was in Class III. Correlation test showed that some physico- chemical parameters have significant correlation with each other. Water Quality Index (WQI) analysis showed that the mean WQI value for the month of July is 96.88 (Class I) while for December, the WQI value deteriorated to 84.03 (Class II). According to the calculated values of WQI and comparison with INWQS, the index of water quality in Pelepah Kanan River is in the clean category and is not affected by pollution neither anthropogenic activities nor natural pollution. (author)

Resuscitation of preterm infants: delivery room interventions and their effect on outcomes.

LENUS (Irish Health Repository)

O'Donnell, Colm P F

2012-12-01

Despite advances in neonatal care, the rate of oxygen dependence at 36 weeks\\' postmenstrual age or bronchopulmonary dysplasia has not fallen. Neonatologists are increasingly careful to apply ventilation strategies that are gentle to the lung in the neonatal intensive care unit. However, there has not been the same emphasis applying gentle ventilation strategies immediately after birth. A lung-protective strategy should start immediately after birth to establish a functional residual capacity, reduce volutrauma and atelectotrauma, facilitate gas exchange, and improve oxygenation during neonatal transition. This article discusses techniques and equipment recommended by international resuscitation guidelines during breathing assistance in the delivery room.

Analysis of architect’s performance indicators in project delivery process

Science.gov (United States)

Marisa, A.

2018-03-01

Architect as a professional in the construction industry should possess a good performance in project delivery process. As a design professional, architect has an important role to ensure that the process is well-conducted by delivering a high-quality product for the clients. Thus, analyzing architect’s performance indicators is crucial in the project delivery process. This study aims to analyze the relative importance of architect performance indicators in project delivery process among registered architects in North Sumatera, Indonesia. A total of five indicators that measure architect performance in project delivery process were identified and 110 completed questionnaires were obtained and used for data analysis. A relative importance index is used to rank the relative importance of architect performance indicators. Results indicate that focus on the clients is the most important indicator of architect performance in project delivery process. This study demonstrates project communication as one of crucial indicators perceived by the architects for measuring their performance, and fills a knowledge gap on the importance of identifying the most important indicator for measuring architect performance from their own perspectives which previous studies have overlooked to improve performance assessment in project delivery process.

Frontal lobe oxygenation is maintained during hypotension following propofol-fentanyl anesthesia

DEFF Research Database (Denmark)

Nissen, P.; Lieshout, J.J. van; Nielsen, H.B.

2009-01-01

Near-infrared spectroscopy (NIRS) assesses cerebral oxygen saturation (Sco2) as a balance between cerebral oxygen delivery and consumption. In 71 patients, we evaluated whether marked reduction in mean arterial pressure (MAP) during propofol-fentanyl anesthesia induction affects frontal lobe Sco2....... The NIRS-determined arm muscle oxygenation (Smo2), heart rate (HR), and cardiac output (CO) were monitored, endtidal carbon dioxide tension was controlled at 3.5 to 4.5 kPa, and central blood volume was maintained. Before anesthesia, the median (range) MAP, HR, and CO were 93 mm Hg (61-126 mm Hg), 76 beats......, the median (range) NIRS-determined Smo2 also decreased (73% [54%-94%] to 71% [52%-87%]), whereas Sco2 increased from 67% (46%-93%) to 74% (48%-95%) (P anesthesia induction, variables recovered and remained at preanesthetic levels during surgery. The findings...

Drivers of Prenatal Care Quality and Uptake of Supervised Delivery ...

African Journals Online (AJOL)

towards improving maternal health include barriers of access to healthcare ... for non-utilization of supervised delivery services in Ghana is the provision of poor .... information relating to the womens socio-demographic characteristics-age ..... Adjei S, Graham W. The skilled attendance index: Proposal for a new measure.

Oxygen supplementation to stabilize preterm infants in the fetal to neonatal transition: no satisfactory answer.

Directory of Open Access Journals (Sweden)

Isabel eTorres-Cuevas

2016-04-01

Full Text Available Fetal life elapses in a relatively low oxygen environment. Immediately after birth with the initiation of breathing the lung expands and oxygen availability to tissue rises by twofold generating a physiologic oxidative stress. However, both lung anatomy and function and the antioxidant defense system do not mature until late in gestation and therefore very preterm infants often need respiratory support and oxygen supplementation in the delivery room to achieve postnatal stabilization. Notably, interventions in the first minutes of life can have long-lasting consequences. Recent trials have aimed to assess what initial inspiratory fraction of oxygen and what oxygen targets during this transitional period are best for extremely preterm infants based on the available nomogram. However, oxygen saturation nomogram informs only of term and late preterm infants but not on extremely preterm infants. Therefore, the solution to this conundrum may still have to wait before a satisfactory answer is available.

Two-photon NADH imaging exposes boundaries of oxygen diffusion in cortical vascular supply regions.

Science.gov (United States)

Kasischke, Karl A; Lambert, Elton M; Panepento, Ben; Sun, Anita; Gelbard, Harris A; Burgess, Robert W; Foster, Thomas H; Nedergaard, Maiken

2011-01-01

Oxygen transport imposes a possible constraint on the brain's ability to sustain variable metabolic demands, but oxygen diffusion in the cerebral cortex has not yet been observed directly. We show that concurrent two-photon fluorescence imaging of endogenous nicotinamide adenine dinucleotide (NADH) and the cortical microcirculation exposes well-defined boundaries of tissue oxygen diffusion in the mouse cortex. The NADH fluorescence increases rapidly over a narrow, very low pO(2) range with a p(50) of 3.4 ± 0.6 mm Hg, thereby establishing a nearly binary reporter of significant, metabolically limiting hypoxia. The transient cortical tissue boundaries of NADH fluorescence exhibit remarkably delineated geometrical patterns, which define the limits of tissue oxygen diffusion from the cortical microcirculation and bear a striking resemblance to the ideal Krogh tissue cylinder. The visualization of microvessels and their regional contribution to oxygen delivery establishes penetrating arterioles as major oxygen sources in addition to the capillary network and confirms the existence of cortical oxygen fields with steep microregional oxygen gradients. Thus, two-photon NADH imaging can be applied to expose vascular supply regions and to localize functionally relevant microregional cortical hypoxia with micrometer spatial resolution.

Risk of cesarean delivery among pregnant women with class III obesity.

Science.gov (United States)

Borghesi, Yves; Labreuche, Julien; Duhamel, Alain; Pigeyre, Marie; Deruelle, Philippe

2017-02-01

To identify factors associated with cesarean delivery among women with class III obesity attempting vaginal delivery. In a retrospective study, medical charts were reviewed for women aged 18 years or older with a singleton pregnancy of at least 37 weeks and a body mass index (calculated as weight in kilograms divided by the square of height in meters) of 40 or higher who were eligible to attempt vaginal delivery at a maternity hospital in Lille, France, between 1999 and 2012. Among 345 eligible women, 301 (87.2%) attempted vaginal delivery; 211 (70.1%) were successful and 90 (29.9%) delivered by cesarean. The frequency of nulliparity was higher among those undergoing cesarean after a trial of labor (64 [71.1%]) than among those who delivered vaginally (57 [27.0%]; Pcesarean (61 [67.8%] vs 96 [45.5%]; Pcesarean among women attempting vaginal delivery (odds ratio [OR] 2.30, 95% confidence interval [CI] 1.25-4.22), whereas history of vaginal delivery was protective (OR 0.08, 95% CI 0.04-0.17). Nulliparous women with class III obesity attempting a vaginal delivery should be warned of the high risk of cesarean delivery, especially if they require induction. © 2016 International Federation of Gynecology and Obstetrics.

Complications of cesarean delivery in the massively obese parturient.

Science.gov (United States)

Alanis, Mark C; Villers, Margaret S; Law, Tameeka L; Steadman, Elizabeth M; Robinson, Christopher J

2010-09-01

The objective of the study was to determine predictors of cesarean delivery morbidity associated with massive obesity. This was an institutional review board-approved retrospective study of massively obese women (body mass index, > or = 50 kg/m(2)) undergoing cesarean delivery. Bivariable and multivariable analyses were used to assess the strength of association between wound complication and various predictors. Fifty-eight of 194 patients (30%) had a wound complication. Most (90%) were wound disruptions, and 86% were diagnosed after hospital discharge (median postoperative day, 8.5; interquartile range, 6-12). Subcutaneous drains and smoking, but not labor or ruptured membranes, were independently associated with wound complication after controlling for various confounders. Vertical abdominal incisions were associated with increased operative time, blood loss, and vertical hysterotomy. Women with a body mass index > or = 50 kg/m(2) have a much greater risk for cesarean wound complications than previously reported. Avoidance of subcutaneous drains and increased use of transverse abdominal wall incisions should be considered in massively obese parturients to reduce operative morbidity. Published by Mosby, Inc.

Nanoparticle-based drug delivery systems: promising approaches against infections

International Nuclear Information System (INIS)

Ranghar, Shweta; Sirohi, Parul; Verma, Pritam; Agarwal, Vishnu

2014-01-01

Despite the fact that many new drugs and technologies have been developed to combat the infectious diseases, these have continued to be global health challenges. The use of conventional antimicrobial agents against these infections is always associated with problems such as the development of multiple drug resistance and adverse side effects. In addition, the inefficient traditional drug delivery system results in inadequate therapeutic index, low bioavailability of drugs and many other limitations. In this regard, antimicrobial nanoparticles and nanosized drug delivery carriers have emerged as potent effective agents against the infections. Nanoparticles have unique properties owing to their ultra small and controllable size such as high surface area, enhanced reactivity, and functionalizable structure. This review focused on different classes of antimicrobial nanoparticles, including metal, metal oxide and others along with their mechanism of action and their potential use against the infections. The review also focused on the development of nanoparticle systems for antimicrobial drug delivery and use of these systems for delivery of various antimicrobial agents, giving an overview about modern nanoparticle based therapeutic strategies against the infections. (author)

Nanoparticle-based drug delivery systems: promising approaches against infections

Energy Technology Data Exchange (ETDEWEB)

Ranghar, Shweta; Sirohi, Parul [Department of Applied Mechanics, Motilal Nehru National Institute of Technology, Allahabad (India); Verma, Pritam; Agarwal, Vishnu [Department of Biotechnology, Motilal Nehru National Institute of Technology, Allahabad (India)

2014-03-15

Despite the fact that many new drugs and technologies have been developed to combat the infectious diseases, these have continued to be global health challenges. The use of conventional antimicrobial agents against these infections is always associated with problems such as the development of multiple drug resistance and adverse side effects. In addition, the inefficient traditional drug delivery system results in inadequate therapeutic index, low bioavailability of drugs and many other limitations. In this regard, antimicrobial nanoparticles and nanosized drug delivery carriers have emerged as potent effective agents against the infections. Nanoparticles have unique properties owing to their ultra small and controllable size such as high surface area, enhanced reactivity, and functionalizable structure. This review focused on different classes of antimicrobial nanoparticles, including metal, metal oxide and others along with their mechanism of action and their potential use against the infections. The review also focused on the development of nanoparticle systems for antimicrobial drug delivery and use of these systems for delivery of various antimicrobial agents, giving an overview about modern nanoparticle based therapeutic strategies against the infections. (author)

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

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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.

Efficiency performance of China's health care delivery system.

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Zhang, Luyu; Cheng, Gang; Song, Suhang; Yuan, Beibei; Zhu, Weiming; He, Li; Ma, Xiaochen; Meng, Qingyue

2017-07-01

Improving efficiency performance of the health care delivery system has been on the agenda for the health system reform that China initiated in 2009. This study examines the changes in efficiency performance and determinants of efficiency after the reform to provide evidence to assess the progress of the reform from the perspective of efficiency. Descriptive analysis, Data Envelopment Analysis, the Malmquist Index, and multilevel regressions are used with data from multiple sources, including the World Bank, the China Health Statistical Yearbook, and routine reports. The results indicate that over the last decade, health outcomes compared with health investment were relatively higher in China than in most other countries worldwide, and the trend was stable. The overall efficiency and total factor productivity increased after the reform, indicating that the reform was likely to have had a positive impact on the efficiency performance of the health care delivery system. However, the health care delivery structure showed low system efficiency, mainly attributed to the weakened primary health care system. Strengthening the primary health care system is central to enhancing the future performance of China's health care delivery system. Copyright © 2017 John Wiley & Sons, Ltd.

Pancreas Oxygen Persufflation Increases ATP Levels as Shown by Nuclear Magnetic Resonance

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Scott, W.E.; Weegman, B.P.; Ferrer-Fabrega, J.; Stein, S.A.; Anazawa, T.; Kirchner, V.A.; Rizzari, M.D.; Stone, J.; Matsumoto, S.; Hammer, B.E.; Balamurugan, A.N.; Kidder, L.S.; Suszynski, T.M.; Avgoustiniatos, E.S.; Stone, S.G.; Tempelman, L.A.; Sutherland, D.E.R.; Hering, B.J.; Papas, K.K.

2010-01-01

Background Islet transplantation is a promising treatment for type 1 diabetes. Due to a shortage of suitable human pancreata, high cost, and the large dose of islets presently required for long-term diabetes reversal; it is important to maximize viable islet yield. Traditional methods of pancreas preservation have been identified as suboptimal due to insufficient oxygenation. Enhanced oxygen delivery is a key area of improvement. In this paper, we explored improved oxygen delivery by persufflation (PSF), ie, vascular gas perfusion. Methods Human pancreata were obtained from brain-dead donors. Porcine pancreata were procured by en bloc viscerectomy from heparinized donation after cardiac death donors and were either preserved by either two-layer method (TLM) or PSF. Following procurement, organs were transported to a 1.5-T magnetic resonance (MR) system for 31P nuclear magnetic resonance spectroscopy to investigate their bioenergetic status by measuring the ratio of adenosine triphosphate to inorganic phosphate (ATP:Pi) and for assessing PSF homogeneity by MRI. Results Human and porcine pancreata can be effectively preserved by PSF. MRI showed that pancreatic tissue was homogeneously filled with gas. TLM can effectively raise ATP:Pi levels in rat pancreata but not in larger porcine pancreata. ATP:Pi levels were almost undetectable in porcine organs preserved with TLM. When human or porcine organs were preserved by PSF, ATP:Pi was elevated to levels similar to those observed in rat pancreata. Conclusion The methods developed for human and porcine pancreas PSF homogeneously deliver oxygen throughout the organ. This elevates ATP levels during preservation and may improve islet isolation outcomes while enabling the use of marginal donors, thus expanding the usable donor pool. PMID:20692395

Estimation of Physiological Cost Index as an Energy Expenditure Index using MacGregor’s Equation

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Binaya SJB Rana

2015-09-01

Full Text Available Introduction: Physical activity and energy expenditure can be quantified by measuring heart rate, oxygen uptake and respiratory quotient. The Physiological Cost Index (PCI proposed by MacGregor is a simple and straightforward method to estimate the energy expenditure index. Here, we aim to estimate the energy expenditure among young Asian population using MacGregor’s equation. Methods: A total of 50 young randomly selected healthy females performed 50m, 100m and 150m walking test at their self-selected preferred speed. The physiological cost index values for 100 m walk at speeds slower and faster than the preferred speed were also obtained. The physiological cost index during exercise was calculated using MacGregor’s equation considering heart rate and speed of walking over the varying distances. Results: The PCI values on three different distances are consistent during self selected preferred speed. The PCI estimation on second and third tests for all three distances walked consistently reproducible. However for each distance walked, the first test the PCI was significantly higher than the second and third test values. The PCI values increased significantly when subjects walked either slower (p = 0.02 or faster (p = 0.001 than their normal preferred speed. Conclusion: The physiological cost index values were similar for varying distances walks. The PCI was the least at the preferred speed of walking and increased when the subjects either walked slower or faster than the preferred speed. The first estimation was higher than subsequent estimations. Keywords: energy expenditure index; exercise; physiological cost index. | PubMed

Maternal obesity, caesarean delivery and caesarean delivery on maternal request: a cohort analysis from China.

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Zhou, Yubo; Blustein, Jan; Li, Hongtian; Ye, Rongwei; Zhu, Liping; Liu, Jianmeng

2015-05-01

To quantify the association between maternal obesity and caesarean delivery, particularly caesarean delivery on maternal request (CDMR), a fast-growing component of caesarean delivery in many nations. We followed 1,019,576 nulliparous women registered in the Perinatal Healthcare Surveillance System during 1993-2010. Maternal body mass index (BMI, kg/m(2) ), before pregnancy or during early pregnancy, was classified as underweight (obese (≥27.5), consistent with World Health Organization guidelines for Asian people. The association between maternal obesity and overall caesarean and its subtypes was modelled using log-binomial regression. During the 18-year period, 404,971 (39.7%) caesareans and 93,927 (9.2%) CDMRs were identified. Maternal obesity was positively associated with overall caesarean and CDMR. Adjusted risk ratios for overall caesarean in the four ascending BMI categories were 0.96 [95% confidence interval (CI) 0.94, 0.97], 1.00 (Reference), 1.16 [95% CI 1.14, 1.18], 1.39 [95% CI 1.43, 1.54], and for CDMR were 0.95 [95% CI 0.94, 0.96], 1.00 (Reference), 1.20 [95% CI 1.18, 1.22], 1.48 [95% CI 1.433, 1.54]. Positive associations were consistently found in women residing in southern and northern provinces and in subgroups stratified by year of delivery, urban or rural residence, maternal age, education, level of delivering hospital, and birthweight. In a large Chinese cohort study, maternal obesity was associated with an increased risk of caesarean delivery and its subtypes, including CDMR. Given the rising global prevalence of obesity, and in view of the growth of CDMR, it seems likely that caesarean births will increase, unless there are changes in obstetrical practice. © 2015 John Wiley & Sons Ltd.

Dynamic oxygen-enhanced magnetic resonance imaging of the lung in asthma—Initial experience

International Nuclear Information System (INIS)

Zhang, Wei-Juan; Niven, Robert M.; Young, Simon S.; Liu, Yu-Zhen; Parker, Geoffrey J.M.; Naish, Josephine H.

2015-01-01

Highlights: • Oxygen-enhanced MRI may have a role in the estimation of disease severity in asthma. • Heterogeneity of parameter maps reflects localized functional impairment in asthma. • OE-MRI provides non-ionising, spatial and temporal information on oxygen delivery. - Abstract: Objectives: To prospectively estimate the feasibility and reproducibility of dynamic oxygen-enhanced magnetic resonance imaging (OE-MRI) in the assessment of regional oxygen delivery, uptake and washout in asthmatic lungs. Materials and methods: The study was approved by the National Research Ethics Committee and written informed consent was obtained. Dynamic OE-MRI was performed twice at one month apart on four mild asthmatic patients (23 ± 5 years old, FEV 1 = 96 ± 3% of predicted value) and six severe asthmatic patients (41 ± 12 years old, FEV 1 = 60 ± 14% of predicted value) on a 1.5 T MR scanner using a two-dimensional T 1 -weighted inversion-recovery turbo spin echo sequence. The enhancing fraction (EF), the maximal change in the partial pressure of oxygen in lung tissue (ΔPO 2max l ) and arterial blood of the aorta (ΔPO 2max a ), and the oxygen wash-in (τ up l , τ up a ) and wash-out (τ down l , τ down a ) time constants were extracted and compared between groups using the independent-samples t-test (two-tailed). Correlations between imaging readouts and clinical measurements were assessed by Pearson's correlation analysis. Bland–Altman analysis was used to estimate the levels of agreement between the repeat scans and the intra-observer agreement in the MR imaging readouts. Results: The severe asthmatic group had significantly smaller EF (70 ± 16%) and median ΔPO 2max l (156 ± 52 mmHg) and significantly larger interquartile range of τ up l (0.84 ± 0.26 min) than the mild asthmatic group (95 ± 3%, P = 0.014; 281 ± 40 mmHg, P = 0.004; 0.20 ± 0.07 min, P = 0.001, respectively). EF, median ΔPO 2max l and τ down l and the interquartile range of τ up l

An overview of Ball Aerospace cryogen storage and delivery systems

International Nuclear Information System (INIS)

Marquardt, J; Keller, J; Mills, G; Schmidt, J

2015-01-01

Starting on the Gemini program in the 1960s, Beech Aircraft (now Ball Aerospace) has been designing and manufacturing dewars for a variety of cryogens including liquid hydrogen and oxygen. These dewars flew on the Apollo, Skylab and Space Shuttle spacecraft providing fuel cell reactants resulting in over 150 manned spaceflights. Since Space Shuttle, Ball has also built the liquid hydrogen fuel tanks for the Boeing Phantom Eye unmanned aerial vehicle. Returning back to its fuel cell days, Ball has designed, built and tested a volume-constrained liquid hydrogen and oxygen tank system for reactant delivery to fuel cells on unmanned undersea vehicles (UUVs). Herein past history of Ball technology is described. Testing has been completed on the UUV specific design, which will be described. (paper)

Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

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Persi Bruno

2010-10-01

Full Text Available Abstract Introduction High frequency percussive ventilation is a ventilatory technique that delivers small bursts of high flow respiratory gas into the lungs at high rates. It is classified as a pneumatically powered, pressure-regulated, time-cycled, high-frequency flow interrupter modality of ventilation. High frequency percussive ventilation improves the arterial partial pressure of oxygen with the same positive end expiratory pressure and fractional inspiratory oxygen level as conventional ventilation using a minor mean airway pressure in an open circuit. It reduces the barotraumatic events in a hypoxic patient who has low lung-compliance. To the best of our knowledge, there have been no papers published about this ventilation modality in patients with severe hypoxaemia after cardiac surgery. Case presentation A 75-year-old Caucasian man with an ejection fraction of 27 percent, developed a lung infection with severe hypoxaemia [partial pressure of oxygen/fractional inspiratory oxygen of 90] ten days after cardiac surgery. Conventional ventilation did not improve the gas exchange. He was treated with high frequency percussive ventilation for 12 hours with a low conventional respiratory rate (five per minute. His cardiac output and systemic and pulmonary pressures were monitored. Compared to conventional ventilation, high frequency percussive ventilation gives an improvement of the partial pressure of oxygen from 90 to 190 mmHg with the same fractional inspiratory oxygen and positive end expiratory pressure level. His right ventricular stroke work index was lowered from 19 to seven g-m/m2/beat; his pulmonary vascular resistance index from 267 to 190 dynes•seconds/cm5/m2; left ventricular stroke work index from 28 to 16 gm-m/m2/beat; and his pulmonary arterial wedge pressure was lowered from 32 to 24 mmHg with a lower mean airway pressure compared to conventional ventilation. His cardiac index (2.7 L/min/m2 and ejection fraction (27 percent

Service readiness, health facility management practices, and delivery care utilization in five states of Nigeria: a cross-sectional analysis.

Science.gov (United States)

Gage, Anastasia J; Ilombu, Onyebuchi; Akinyemi, Akanni Ibukun

2016-10-06

Existing studies of delivery care in Nigeria have identified socioeconomic and cultural factors as the primary determinants of health facility delivery. However, no study has investigated the association between supply-side factors and health facility delivery. Our study analyzed the role of supply-side factors, particularly health facility readiness and management practices for provision of quality maternal health services. Using linked data from the 2005 and 2009 health facility and household surveys in the five states in which the Community Participation for Action in the Social Sector (COMPASS) project was implemented, indices of health service readiness and management were developed based on World Health Organization guidelines. Multilevel logistic regression models were run to determine the association between these indices and health facility delivery among 2710 women aged 15-49 years whose last child was born within the five years preceding the surveys and who lived in 51 COMPASS LGAs. The health facility delivery rate increased from 25.4 % in 2005 to 44.1 % in 2009. Basic amenities for antenatal care provision, readiness to deliver basic emergency obstetric and newborn care, and management practices supportive of quality maternal health services were suboptimal in health facilities surveyed and did not change significantly between 2005 and 2009. The LGA mean index of basic amenities for antenatal care provision was more positively associated with the odds of health facility delivery in 2009 than in 2005, and in rural than in urban areas. The LGA mean index of management practices was associated with significantly lower odds of health facility delivery in rural than in urban areas. The LGA mean index of facility readiness to deliver basic emergency obstetric and neonatal care declined slightly from 5.16 in 2005 to 3.98 in 2009 and was unrelated to the odds of health facility delivery. Supply-side factors appeared to play a role in health facility delivery

An On-Line Oxygen Forecasting System for Waterless Live Transportation of Flatfish Based on Feature Clustering

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Yongjun Zhang

2017-09-01

Full Text Available Accurate prediction of forthcoming oxygen concentration during waterless live fish transportation plays a key role in reducing the abnormal occurrence, increasing the survival rate in delivery operations, and optimizing manufacturing costs. The most effective ambient monitoring techniques that are based on the analysis of historical process data when performing forecasting operations do not fully consider current ambient influence. This is likely lead to a greater deviation in on-line oxygen level forecasting in real situations. Therefore, it is not advisable for the system to perform early warning and on-line air adjustment in delivery. In this paper, we propose a hybrid method and its implementation system that combines a gray model (GM (1, 1 with least squares support vector machines (LSSVM that can be used effectively as a forecasting model to perform early warning effectively according to the dynamic changes of oxygen in a closed system. For accurately forecasting of the oxygen level, the fuzzy C-means clustering (FCM algorithm was utilized for classification according to the flatfish’s physical features—i.e., length and weight—for more pertinent training. The performance of the gray model-particle swarm optimization-least squares support vector machines (GM-PSO-LSSVM model was compared with the traditional modeling approaches of GM (1, 1 and LSSVM by applying it to predict on-line oxygen level, and the results showed that its predictions were more accurate than those of the LSSVM and grey model. Therefore, it is a suitable and effective method for abnormal condition forecasting and timely control in the waterless live transportation of flatfish.

Severe myocardial injury and extracorporeal membrane oxygenation following perinatal asphyxia

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P. Benson Ham

2015-05-01

Full Text Available Perinatal asphyxia is a common cause of morbidity and mortality in the newborn and is associated with myocardial injury in a significant proportion of cases. Biomarkers, echocardiography, and rhythm disturbances are sensitive indicators of myocardial ischemia and may predict mortality. We present a case of severe myocardial dysfunction immediately after delivery managed with extracorporeal membrane oxygenation (ECMO and discuss the role of cardiac biomarkers, echocardiography, electrocardiography, and ECMO in the asphyxiated newborn.

Drug delivery strategies for chemoprevention of UVB-induced skin cancer: A review.

Science.gov (United States)

Bagde, Arvind; Mondal, Arindam; Singh, Mandip

2018-01-01

Annually, more skin cancer cases are diagnosed than the collective incidence of the colon, lung, breast, and prostate cancer. Persistent contact with sunlight is a primary cause for all the skin malignancies. UVB radiation induces reactive oxygen species (ROS) production in the skin which eventually leads to DNA damage and mutation. Various delivery approaches for the skin cancer treatment/prevention have been evolving and are directed toward improvements in terms of delivery modes, therapeutic agents, and site-specificity of therapeutics delivery. The effective chemoprevention activity achieved is based on the efficiency of the delivery system used and the amount of the therapeutic molecule deposited in the skin. In this article, we have discussed different studies performed specifically for the chemoprevention of UVB-induced skin cancer. Ultra-flexible nanocarriers, transethosomes nanocarriers, silica nanoparticles, silver nanoparticles, nanocapsule suspensions, microemulsion, nanoemulsion, and polymeric nanoparticles which have been used so far to deliver the desired drug molecule for preventing the UVB-induced skin cancer. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Preparation and Characterization of Bragg Fibers for Delivery of Laser Radiation at 1064 nm

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V. Matejec

2013-04-01

Full Text Available Bragg fibers offer new performance for transmission of high laser energies over long distances. In this paper theoretical modeling, preparation and characterization of Bragg fibers for delivery laser radiation at 1064 nm are presented. Investigated Bragg fibers consist of the fiber core with a refractive index equal to that of silica which is surrounded by three pairs of circular layers. Each pair is composed of one layer with a high and one layer with a low refractive index and characterized by a refractive-index difference around 0.03. Propagation constants and radiation losses of the fundamental mode in such a structure were calculated on the basis of waveguide optics. Preforms of the Bragg fibers were prepared by the MCVD method using germanium dioxide, phosphorous pentoxide and fluorine as silica dopants. The fibers with a diameter of 170 m were drawn from the preforms. Refractive-index profiles, angular distributions of the output power and optical losses of the prepared fibers were measured. Results of testing the fibers for delivery radiation of a pulse Nd:YAG laser at 1064 nm are also shown.

Liposome as nanocarrier: Site targeted delivery in lung cancer

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Najeeb Ullah

2017-08-01

Full Text Available Lung cancer is fatal and spreading rapidly worldwide. Different clinical strategies are applied to stop this cancer. As the lung is a delicate organ, special clinical applications must be used and nanodrugs delivery systems are the most important applications of all. This review discusses the lung problems such as lung cancer, lung inflammation and bronchi constrictions followed by repetitive intake of some drugs. The objective of this review is to study how nanodrug delivery systems were synthesized and used in lung disorder treatment especially in lung cancer. The authors studied some articles from 1989 to 2015. Liposome encapsulation was done in various ways for the delivery of different drugs such as metaproterenol into liposomes caused bronchodilation, immunoliposomes bearing antibodies for doxorubicin reduced 50% inhibitory effects, radioliposomes with high penetrating ability to peripheral airways, aerosol delivery systems with deep pulmonary deposition, polymeric drug delivery having potential to improve beneficial index of drug, solid lipid liposomes, liposomal gentamicin with altered different clinical susceptibilities of resistance, transferrin conjugated liposomes to deliver cytostatic drugs to site of lungs, anti-inflammatory drugs with mannosylated liposomes, liposomal suspensions with single stranded RNAs and peptide encapsulation of liposomes. This review indicates that many animals perished with intravenous administration of drugs but survived in liposomal targeting groups.

Sources of oxygen flux in groundwater during induced bank filtration at a site in Berlin, Germany

Science.gov (United States)

Kohfahl, Claus; Massmann, Gudrun; Pekdeger, Asaf

2009-05-01

The microbial degradation of pharmaceuticals found in surface water used for artificial recharge is strongly dependent on redox conditions of the subsurface. Furthermore the durability of production wells may decrease considerably with the presence of oxygen and ferrous iron due to the precipitation of trivalent iron oxides and subsequent clogging. Field measurements are presented for oxygen at a bank filtration site in Berlin, Germany, along with simplified calculations of different oxygen pathways into the groundwater. For a two-dimensional vertical cross-section, oxygen input has been calculated for six scenarios related to different water management strategies. Calculations were carried out in order to assess the amount of oxygen input due to (1) the infiltration of oxic lake water, (2) air entrapment as a result of water table oscillations, (3) diffusive oxygen flux from soil air and (4) infiltrating rainwater. The results show that air entrapment and infiltrating lake water during winter constitute by far the most important mechanism of oxygen input. Oxygen input by percolating rainwater and by diffusive delivery of oxygen in the gas phase is negligible. The results exemplify the importance of well management as a determining factor for water oscillations and redox conditions during artificial recharge.

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

The oxygen reactivity index and its relation to sensor technology in patients with severe brain lesions.

Science.gov (United States)

Dengler, Julius; Frenzel, Christin; Vajkoczy, Peter; Horn, Peter; Wolf, Stefan

2013-08-01

The oxygen reactivity index (ORx) has been introduced to assess the status of cerebral autoregulation after traumatic brain injury (TBI) or subarachnoid hemorrhage (SAH). Currently, there is some controversy about whether the ORx depends on the type of PbrO2-sensor technology used for its calculation. To examine if the probe technology does matter, we compared the ORx and the resulting optimal cerebral perfusion pressures (CPPopt) of simultaneously implanted Licox (CC1.SB, Integra Neuroscience, France) and Neurovent-PTO (Raumedic, Germany) probes in patients after aneurysmal SAH or severe TBI. Licox and Raumedic probes were implanted side by side in 11 patients after TBI or SAH. ORx and CPPopt were recorded continuously. The equivalence of both probes was examined using Bland-Altman analyses. The mean difference in ORx was 0.1, with Licox producing higher values. The limits of agreement regarding ORx ranged from -0.6 to +0.7. When both probes' ORx values were compared in each patient, no specific pattern in their relationship was seen. The mean difference in CPPopt was 0 mmHg with limits of agreement between -16.5 and +16.4 mmHg. Owing to the rather limited number of patients, we view the results of this study as preliminary. The main result is that Licox and Raumedic showed consistent differences in ORx and CPPopt. Therefore, ORx values of both probes cannot be interchanged and should not be viewed as equivalent. This should be taken into consideration when discussing ORx data generated by different PbrO2 probe types.

Effects of vacuum suctioning and strategic drape tenting on oxygen concentration in a simulated surgical field.

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Kung, Theodore A; Kong, Sarah W; Aliu, Oluseyi; Azizi, Jahan; Kai, Salim; Cederna, Paul S

2016-02-01

To investigate the isolated and combined effects of vacuum suctioning and strategic drape tenting on oxygen concentration in an experimental setting. Experimental. Clinical simulation center of a university-affiliated hospital. Mannequin simulation of a patient undergoing facial surgery under sedation anesthesia. Supplemental oxygen was delivered via nasal cannula. Vacuum suctioning and strategic drape tenting. The experimental trials entailed measuring oxygen concentration around the nasal cannula continuously either in the presence or absence of a standard operating room vacuum suction system and strategic tenting of surgical drapes. The primary outcome was the time required for oxygen concentration to reach 21%. In the control group (without suction or strategic tenting), a mean time of 180 seconds elapsed until the measured oxygen concentration reached 21% after cessation of oxygen delivery. Use of a vacuum suction device alone (110 seconds; P strategic tenting (110 seconds; P strategic tenting of surgical drapes has a theoretical benefit to decreasing the pooling of oxygen around the surgical site, further investigation is necessary before its routine use is recommended. Copyright © 2016 Elsevier Inc. All rights reserved.

Aptamer-Mediated Polymeric Vehicles for Enhanced Cell-Targeted Drug Delivery.

Science.gov (United States)

Tan, Kei X; Danquah, Michael K; Sidhu, Amandeep; Yon, Lau Sie; Ongkudon, Clarence M

2018-02-08

The search for smart delivery systems for enhanced pre-clinical and clinical pharmaceutical delivery and cell targeting continues to be a major biomedical research endeavor owing to differences in the physicochemical characteristics and physiological effects of drug molecules, and this affects the delivery mechanisms to elicit maximum therapeutic effects. Targeted drug delivery is a smart evolution essential to address major challenges associated with conventional drug delivery systems. These challenges mostly result in poor pharmacokinetics due to the inability of the active pharmaceutical ingredients to specifically act on malignant cells thus, causing poor therapeutic index and toxicity to surrounding normal cells. Aptamers are oligonucleotides with engineered affinities to bind specifically to their cognate targets. Aptamers have gained significant interests as effective targeting elements for enhanced therapeutic delivery as they can be generated to specifically bind to wide range of targets including proteins, peptides, ions, cells and tissues. Notwithstanding, effective delivery of aptamers as therapeutic vehicles is challenged by cell membrane electrostatic repulsion, endonuclease degradation, low pH cleavage, and binding conformation stability. The application of molecularly engineered biodegradable and biocompatible polymeric particles with tunable features such as surface area and chemistry, particulate size distribution and toxicity creates opportunities to develop smart aptamer-mediated delivery systems for controlled drug release. This article discusses opportunities for particulate aptamer-drug formulations to advance current drug delivery modalities by navigating active ingredients through cellular and biomolecular traffic to target sites for sustained and controlled release at effective therapeutic dosages while minimizing systemic cytotoxic effects. A proposal for a novel drug-polymer-aptamer-polymer (DPAP) design of aptamer-drug formulation with

The effect of the transfusion of stored RBCs on intestinal microvascular oxygenation in the rat

NARCIS (Netherlands)

van Bommel, J.; de Korte, D.; Lind, A.; Siegemund, M.; Trouwborst, A.; Verhoeven, A. J.; Ince, C.; Henny, C. P.

2001-01-01

Although it is known that the transfusion of stored RBCs does not always improve tissue O(2) consumption under conditions of limited tissue oxygenation, the efficiency of O(2) delivery to the microcirculation by stored RBCs has never been determined. In a rat hemorrhagic shock model, the effects of

Ultrasound-mediated drug delivery by gas bubbles generated from a chemical reaction.

Science.gov (United States)

Lee, Sungmun; Al-Kaabi, Leena; Mawart, Aurélie; Khandoker, Ahsan; Alsafar, Habiba; Jelinek, Herbert F; Khalaf, Kinda; Park, Ji-Ho; Kim, Yeu-Chun

2018-02-01

Highly echogenic and ultrasound-responsive microbubbles such as nitrogen and perfluorocarbons have been exploited as ultrasound-mediated drug carriers. Here, we propose an innovative method for drug delivery using microbubbles generated from a chemical reaction. In a novel drug delivery system, luminol encapsulated in folate-conjugated bovine serum albumin nanoparticles (Fol-BSAN) can generate nitrogen gas (N 2 ) by chemical reaction when it reacts with hydrogen peroxide (H 2 O 2 ), one of reactive oxygen species (ROS). ROS plays an important role in the initiation and progression of cancer and elevated ROS have been observed in cancer cells both in vitro and in vivo. High-intensity focussed ultrasound (HIFU) is used to burst the N 2 microbubbles, causing site-specific delivery of anticancer drugs such as methotrexate. In this research, the drug delivery system was optimised by using water-soluble luminol and Mobil Composition of Matter-41 (MCM-41), a mesoporous material, so that the delivery system was sensitive to micromolar concentrations of H 2 O 2 . HIFU increased the drug release from Fol-BSAN by 52.9 ± 2.9% in 10 minutes. The cytotoxicity of methotrexate was enhanced when methotrexate is delivered to MDA-MB-231, a metastatic human breast cancer cell line, using Fol-BSAN with HIFU. We anticipate numerous applications of chemically generated microbubbles for ultrasound-mediated drug delivery.

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sorensen, Line C; Maroun, Lisa L; Borch, Klaus

2008-01-01

Aim: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. Methods: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). Conclusion: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired....

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

Energy Technology Data Exchange (ETDEWEB)

Kumar Barik, Ullash; Srinivasan, S; Nagendra, C L; Subrahmanyam, A

2003-04-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson.

Electrical and optical properties of reactive DC magnetron sputtered silver oxide thin films: role of oxygen

International Nuclear Information System (INIS)

Kumar Barik, Ullash; Srinivasan, S.; Nagendra, C.L.; Subrahmanyam, A.

2003-01-01

Silver oxide thin films have been prepared on soda lime glass substrates at room temperature (300 K) by reactive DC Magnetron sputtering technique using pure silver metal target; the oxygen flow rates have been varied in the range 0.00-2.01 sccm. The X-ray diffraction data on these films show a systematic change from metallic silver to silver (sub) oxides. The electrical resistivity increases with increasing oxygen flow. The films show a p-type behavior (by both Hall and Seebeck measurements) for the oxygen flow rates of 0.54, 1.09 and 1.43 sccm. The refractive index of the films (at 632.8 nm) decreases with increasing oxygen content and is in the range 1.167-1.145, whereas the p-type films show a higher refractive index (1.186-1.204). The work function of these silver oxide films has been measured by Kelvin Probe technique. The results, in specific, the p-type conductivity in the silver oxide films, have been explained on the basis of the theory of partial ionic charge proposed by Sanderson

[Regional cerebral oxygen saturation as a marker of hemodynamic state following cardiac surgery].

Science.gov (United States)

García-Hernández, J A; Aldemira-Liz, A; Martínez-López, A I; Cayuela, A; Charlo-Molina, M T; Cano-Franco, J; Loscertales-Abril, M

2013-10-01

Regional cerebral oxygen saturation (rSO₂) is a measure of the general state of perfusion and oxygenation. We aim to analyze the relationship between this and various hemodynamic and respiratory parameters. Forty-three patients, operated on between October 2011 and July 2012, were included in this prospective observational descriptive study. The following parameters were measured: mean arterial pressure, both arterial and central venous oxygen saturation and partial pressures of oxygen and carbon dioxide, and lactate levels. From these parameters, the oxygenation index and the oxygen extraction ratio were calculated. These measurements were studied to evaluate whether rSO₂ correlated significantly with the other parameters. The average age and weight of the patients were 27.3 months and 9.2 kg, respectively. The rSO₂ correlated positively with both central venous oxygen saturation (r=0.73, P 0.4) between the rSO₂ and central venous oxygen saturation, and between the rSO₂ and oxygen extraction ratio. Regional cerebral oxygen saturation correlates well with hemodynamic parameters - mean arterial pressure, venous saturation, and the tissue oxygen extraction. However, it does not correlate with respiratory parameters. Copyright © 2012 Asociación Española de Pediatría. Published by Elsevier Espana. All rights reserved.

Effects of Fiber Type and Size on the Heterogeneity of Oxygen Distribution in Exercising Skeletal Muscle

Science.gov (United States)

Liu, Gang; Mac Gabhann, Feilim; Popel, Aleksander S.

2012-01-01

The process of oxygen delivery from capillary to muscle fiber is essential for a tissue with variable oxygen demand, such as skeletal muscle. Oxygen distribution in exercising skeletal muscle is regulated by convective oxygen transport in the blood vessels, oxygen diffusion and consumption in the tissue. Spatial heterogeneities in oxygen supply, such as microvascular architecture and hemodynamic variables, had been observed experimentally and their marked effects on oxygen exchange had been confirmed using mathematical models. In this study, we investigate the effects of heterogeneities in oxygen demand on tissue oxygenation distribution using a multiscale oxygen transport model. Muscles are composed of different ratios of the various fiber types. Each fiber type has characteristic values of several parameters, including fiber size, oxygen consumption, myoglobin concentration, and oxygen diffusivity. Using experimentally measured parameters for different fiber types and applying them to the rat extensor digitorum longus muscle, we evaluated the effects of heterogeneous fiber size and fiber type properties on the oxygen distribution profile. Our simulation results suggest a marked increase in spatial heterogeneity of oxygen due to fiber size distribution in a mixed muscle. Our simulations also suggest that the combined effects of fiber type properties, except size, do not contribute significantly to the tissue oxygen spatial heterogeneity. However, the incorporation of the difference in oxygen consumption rates of different fiber types alone causes higher oxygen heterogeneity compared to control cases with uniform fiber properties. In contrast, incorporating variation in other fiber type-specific properties, such as myoglobin concentration, causes little change in spatial tissue oxygenation profiles. PMID:23028531

The effects of the mode of delivery on oxidative-antioxidative balance.

Science.gov (United States)

Mutlu, Birgul; Aksoy, Nurten; Cakir, Hale; Celik, Hakim; Erel, Ozcan

2011-11-01

The purpose of this study was to investigate the effects of the mode of delivery on the oxidant and antioxidant systems in mothers and infants and to demonstrate which mode leads more oxidative stress. The participants were divided into two groups according to the mode of their labour and delivery: group 1 (n = 33) women with normal labour and delivery and group 2 (n = 33) with scheduled caesarean section (C/S) and delivery. The maternal, cord, and infant blood samples in both groups were collected. The serum total antioxidant capacity (TAC) and the total oxidant status (TOS) were evaluated by using an automated colorimetric measurement method. The parameters indicating oxidative stress (TOS, oxidative stress index, and lipid hydroperoxide) in maternal, cord, and newborn blood samples were higher in patients delivering with C/S than those normal spontaneous vaginal deliveries (NSVD) patient group, while it was vice versa for TAC. It may be concluded that both the mothers and neonates in C/S group are exposed to higher oxidative stress as compared with those in NSVD group and the antioxidant mechanisms are insufficient to cope with this stress during C/S. This result indicates that the normal delivery through the physiological route is healthier for the bodies of mothers and infants.

A modified method of planning and delivery for dynamic multileaf collimator intensity-modulated radiation therapy

International Nuclear Information System (INIS)

Dogan, Nesrin; Leybovich, Leonid B.; Sethi, Anil; Krasin, Matthew; Emami, Bahman

2000-01-01

Purpose: To develop a modified planning and delivery technique that reduces dose nonuniformity for tomographic delivery of intensity-modulated radiation therapy (IMRT). Methods and Materials: The NOMOS-CORVUS system delivers IMRT in a tomographic paradigm. This type of delivery is prone to create multiple dose nonuniformity regions at the arc abutment regions. The modified technique was based on the cyclical behavior of arc positions as a function of a target length. With the modified technique, two plans are developed for the same patient, one with the original target and the second with a slightly increased target length and the abutment regions shifted by ∼5 mm compared to the first plan. Each plan is designed to deliver half of the target prescription dose delivered on alternate days, resulting in periodic shifts of abutment regions. This method was experimentally tested in phantoms with and without intentionally introduced errors in couch indexing. Results: With the modified technique, the degree of dose nonuniformity was reduced. For example, with 1 mm error in couch indexing, the degree of dose nonuniformity changed from ∼25% to ∼12%. Conclusion: Use of the modified technique reduces dose nonuniformity due to periodic shifts of abutment regions during treatment delivery

Dynamic oxygen-enhanced magnetic resonance imaging of the lung in asthma—Initial experience

Energy Technology Data Exchange (ETDEWEB)

Zhang, Wei-Juan, E-mail: weijuan.zhang@postgrad.manchester.ac.uk [Centre for Imaging Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Biomedical Imaging Institute, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Niven, Robert M., E-mail: robert.niven@uhsm.nhs.uk [North West Lung Research Centre, University Hospital of South Manchester, Southmoor Road, Manchester M23 9LT (United Kingdom); Young, Simon S., E-mail: Simon.Young1@astrazeneca.com [Personalised Healthcare and Biomarkers, AstraZeneca R and D, Alderley Park, Macclesfield SK10 4TF (United Kingdom); Liu, Yu-Zhen, E-mail: yu-zhen.liu@astrazeneca.com [Personalised Healthcare and Biomarkers, AstraZeneca R and D, Alderley Park, Macclesfield SK10 4TF (United Kingdom); Parker, Geoffrey J.M., E-mail: Geoff.parker@manchester.ac.uk [Centre for Imaging Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Biomedical Imaging Institute, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Bioxydyn Limited, Rutherford House, Pencroft Way, Manchester M15 6SZ (United Kingdom); Naish, Josephine H., E-mail: Josephine.naish@manchester.ac.uk [Centre for Imaging Sciences, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom); Biomedical Imaging Institute, The University of Manchester, Oxford Road, Manchester M13 9PT (United Kingdom)

2015-02-15

Highlights: • Oxygen-enhanced MRI may have a role in the estimation of disease severity in asthma. • Heterogeneity of parameter maps reflects localized functional impairment in asthma. • OE-MRI provides non-ionising, spatial and temporal information on oxygen delivery. - Abstract: Objectives: To prospectively estimate the feasibility and reproducibility of dynamic oxygen-enhanced magnetic resonance imaging (OE-MRI) in the assessment of regional oxygen delivery, uptake and washout in asthmatic lungs. Materials and methods: The study was approved by the National Research Ethics Committee and written informed consent was obtained. Dynamic OE-MRI was performed twice at one month apart on four mild asthmatic patients (23 ± 5 years old, FEV{sub 1} = 96 ± 3% of predicted value) and six severe asthmatic patients (41 ± 12 years old, FEV{sub 1} = 60 ± 14% of predicted value) on a 1.5 T MR scanner using a two-dimensional T{sub 1}-weighted inversion-recovery turbo spin echo sequence. The enhancing fraction (EF), the maximal change in the partial pressure of oxygen in lung tissue (ΔPO{sub 2max{sub l}}) and arterial blood of the aorta (ΔPO{sub 2max{sub a}}), and the oxygen wash-in (τ{sub up{sub l}}, τ{sub up{sub a}}) and wash-out (τ{sub down{sub l}}, τ{sub down{sub a}}) time constants were extracted and compared between groups using the independent-samples t-test (two-tailed). Correlations between imaging readouts and clinical measurements were assessed by Pearson's correlation analysis. Bland–Altman analysis was used to estimate the levels of agreement between the repeat scans and the intra-observer agreement in the MR imaging readouts. Results: The severe asthmatic group had significantly smaller EF (70 ± 16%) and median ΔPO{sub 2max{sub l}} (156 ± 52 mmHg) and significantly larger interquartile range of τ{sub up{sub l}} (0.84 ± 0.26 min) than the mild asthmatic group (95 ± 3%, P = 0.014; 281 ± 40 mmHg, P = 0.004; 0.20 ± 0.07 min, P = 0

SU-E-T-127: Application of TG-119 for Evaluation of Proton Spot Scanning Based Planning and Treatment Delivery

Energy Technology Data Exchange (ETDEWEB)

Saini, J; Cao, N; Wong, T [SCCA Proton Therapy, A Procure Center, Seattle, WA (United States); Bowen, S; Bloch, C [University of Washington, School of Medicine, Seattle, WA (United States)

2015-06-15

Purpose: The clinical test cases presented in AAPM TG-119 are used to evaluate the accuracy of treatment planning and delivery through spot scanning proton beams. Methods: An IBA spot scanning delivery system has been commissioned to be used with the RayStation treatment planning system. Various test cases provided in TG-119 were used for planning and delivery verification. The CT dataset and structures as provided by TG-119 were imported into a mock patient. The plans were optimized using the multi field optimization (MFO) to achieve the desired goals. The planner was given the flexibility to achieve the given dose-volume goals by creating appropriate objectives and constraints. Beams were delivered to a phantom and measurements were performed at multiple depths using the MatrixxPT detector array. The analyses were performed on beam by beam basis and quantified using the gamma index. A tolerance of 3%/3 mm in 2D was used for gamma index analysis along with dose threshold of 10%. Results: The clinical goals for targets and critical structures were met or improved for all cases except the C-Shape target with difficult constraints. The minimum gamma index using the 3%/3mm as a criterion is 93.3% for one of the planes measured for C-Shape target. Using 2%/2mm as a criterion, the minimum gamma index drops to 70%. Only Prostate target has all the planes above >90% pass using the 2%/2mm criterion. Conclusion: The overall accuracy of the treatment planning and delivery is deemed clinically acceptable. The test cases with highly modulated beams can have steep gradients in the dose profiles that can reduce the gamma index pass rate. Gamma analysis based on 3D data may be needed for routine use of 2%/2mm criterion. In addition, improvements in modelling of spot profiles in dose engine may be required for further improving the gamma index pass rate.

Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis.

Science.gov (United States)

Clemmesen, J O; Gerbes, A L; Gülberg, V; Hansen, B A; Larsen, F S; Skak, C; Tygstrup, N; Ott, P

1999-02-01

Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P HVP (n=18), DO2,sp increased by 15% (P HVP. Changes of ET-1 were positively correlated with changes in HBF (P HVP (P HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

Thioredoxin and Cancer: A Role for Thioredoxin in all States of Tumor Oxygenation

International Nuclear Information System (INIS)

Karlenius, Therese Christina; Tonissen, Kathryn Fay

2010-01-01

Thioredoxin is a small redox-regulating protein, which plays crucial roles in maintaining cellular redox homeostasis and cell survival and is highly expressed in many cancers. The tumor environment is usually under either oxidative or hypoxic stress and both stresses are known up-regulators of thioredoxin expression. These environments exist in tumors because their abnormal vascular networks result in an unstable oxygen delivery. Therefore, the oxygenation patterns in human tumors are complex, leading to hypoxia/re-oxygenation cycling. During carcinogenesis, tumor cells often become more resistant to hypoxia or oxidative stress-induced cell death and most studies on tumor oxygenation have focused on these two tumor environments. However, recent investigations suggest that the hypoxic cycling occurring within tumors plays a larger role in the contribution to tumor cell survival than either oxidative stress or hypoxia alone. Thioredoxin is known to have important roles in both these cellular responses and several studies implicate thioredoxin as a contributor to cancer progression. However, only a few studies exist that investigate the regulation of thioredoxin in the hypoxic and cycling hypoxic response in cancers. This review focuses on the role of thioredoxin in the various states of tumor oxygenation

Neonatal cerebral oxygenation is not linked to foetal vasculitis and predicts intraventricular haemorrhage in preterm infants

DEFF Research Database (Denmark)

Sørensen, Line Carøe; Maroun, Lisa Leth; Borch, K.

2008-01-01

AIM: The aim of the study was to compare the cerebral tissue oxygenation index (c-TOI) measured by near infrared spectroscopy (NIRS) in infants with and without foetal vasculitis. METHODS: Twenty-four infants with placental signs of a foetal inflammatory response (FIR), foetal vasculitis, were.......002). CONCLUSION: Cerebral oxygenation was not affected in the first day of life in preterm infants born with foetal vasculitis, while cerebral oxygenation in infants that later developed intraventricular haemorrhage was impaired Udgivelsesdato: 2008/11...

Maternal obesity and rate of cesarean delivery in Djibouti.

Science.gov (United States)

Minsart, Anne-Frederique; N'guyen, Thai-Son; Dimtsu, Hirut; Ratsimanresy, Rachel; Dada, Fouad; Ali Hadji, Rachid

2014-11-01

To calculate the prevalence of maternal obesity and to determine the relation between obesity and cesarean delivery in an urban hospital in Djibouti. In an observational cohort study, all women who had a live birth or stillbirth between October 2012 and November 2013 were considered for inclusion. Body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters) was calculated throughout pregnancy, and women with a BMI of at least 30.0 were deemed to be obese. Multivariate logistic regression analyses were used to evaluate the relation between cesarean and obesity. Overall, 100 (24.8%) of 404 women were obese before 14 weeks of pregnancy, as were 112 (25.2%) of 445 before 22 weeks, and 200 (43.2%) of 463 at delivery. Obesity before 22 weeks was associated with a 127% excess risk of cesarean delivery (adjusted odds ratio 2.27; 95% CI 1.07-4.82; P=0.032). Similar trends were found when the analyses were limited to the subgroup of women without a previous cesarean delivery or primiparae. Prevalence of maternal obesity is high in Djibouti City and is related to an excess risk of cesarean delivery, even after controlling for a range of medical and socioeconomic variables. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Delivery mode and neonatal outcome after a trial of external cephalic version (ECV): a prospective trial of vaginal breech versus cephalic delivery.

Science.gov (United States)

Reinhard, Joscha; Sänger, Nicole; Hanker, Lars; Reichenbach, Lena; Yuan, Juping; Herrmann, Eva; Louwen, Frank

2013-04-01

To examine the delivery mode and neonatal outcome after a trial of external cephalic version (ECV) procedures. This is an interim analysis of an ongoing larger prospective off-centre randomised trial, which compares a clinical hypnosis intervention against neuro-linguistic programming (NLP) of women with a singleton breech foetus at or after 37(0/7) (259 days) weeks of gestation and normal amniotic fluid index. Main outcome measures were delivery mode and neonatal outcome. On the same day after the ECV procedure two patients (2 %), who had unsuccessful ECVs, had Caesarean sections (one due to vaginal bleeding and one due to pathological CTG). After the ECV procedure 40.4 % of women had cephalic presentation (n = 38) and 58.5 % (n = 55) remained breech presentation. One patient remained transverse presentation (n = 1; 1.1 %). Vaginal delivery was observed by 73.7 % of cephalic presentation (n = 28), whereas 26.3 % (n = 10) had in-labour Caesarean sections. Of those, who selected a trial of vaginal breech delivery, 42.4 % (n = 14) delivered vaginally and 57.6 % (n = 19) delivered via Caesarean section. There is a statistically significant difference between the rate of vaginal birth between cephalic presentation and trial of vaginal breech delivery (p = 0.009), however, no difference in neonatal outcome was observed. ECV is a safe procedure and can reduce not only the rate of elective Caesarean sections due to breech presentation but also the rate of in-labour Caesarean sections even if a trial of vaginal breech delivery is attempted.

Topical oxygen therapy results in complete wound healing in diabetic foot ulcers.

Science.gov (United States)

Yu, Janelle; Lu, Suzanne; McLaren, Ann-Marie; Perry, Julie A; Cross, Karen M

2016-11-01

Diabetic foot ulcers (DFUs) are a significant problem in an aging population. Fifteen percent of diabetics develop a DFU over their lifetime, which can lead to potential amputation. The 5-year survival rate after amputation is 31%, which is greater than the lifetime risk of mortality from cancer. Topical oxygen is a promising technique for the adjunctive therapy of chronic wounds including DFUs, but few controlled studies exist to support its clinical adoption. The aim of this study was to compare a portable topical oxygen delivery system in patients with nonhealing DFUs to standard best practice. Twenty patients were randomized into a topical oxygen group (n = 10), and a nonplacebo control group with regular dressings and standard care (n = 10), and attended the diabetic foot clinic once weekly for 8 weeks. Ulcer surface area over time was analyzed using standardized digital imaging software. DFUs were present without healing for a mean duration of 76 weeks prior to the study. They found a significant difference in healing rate between patients receiving topical oxygen and those receiving standard care. Topical oxygen, therefore, represents a potentially exciting new technology to shorten healing time in patients with nonhealing DFUs. More prospective randomized and powered studies are needed to determine the benefits of topical oxygen, but our current results are very promising. © 2016 by the Wound Healing Society.

Delivery room management of term and preterm newly born infants.

Science.gov (United States)

Saugstad, Ola Didrik

2015-01-01

Delivery room management, especially in the first 'golden' minute, is of the utmost importance. An exact and universal definition of when a baby is born is needed to obtain agreement on what is meant by the first minute of life. Education of young girls is a basic requirement to optimize the health of the mother and baby. Interventions in pregnancy should as far as possible be evidence based. Antenatal care, the selection of birth mode and antenatal steroid therapy when indicated also contribute to obtaining the best outcome. Delayed cord clamping is recommended for both preterm and term infants. However, more data are needed regarding the most immature infants. Routine suctioning of the mouth and airways is not required. Thermal control is important - keep the temperature in the delivery room at 26°C and wrap infants start with CPAP from the first breath. A T-piece device seems to have some advantages compared to self-inflating bags. Surfactant instillation is often not needed prophylactically provided the mother has received antenatal steroids. Less invasive methods for administering surfactant may be useful. If ventilatory support is needed, start with air in term and near-term infants. For babies of 29-33 weeks of gestation start with 21-30% oxygen and for infants start with 30% oxygen and adjust according to the response obtained. © 2015 S. Karger AG, Basel.

Theoretical analysis and experimental study of oxygen transfer under regular and non-breaking waves

Institute of Scientific and Technical Information of China (English)

尹则高; 梁丙臣; 王乐

2013-01-01

The dissolved oxygen concentration is an important index of water quality, and the atmosphere is one of the important sources of the dissolved oxygen. In this paper, the mass conservation law and the dimensional analysis method are employed to study the oxygen transfer under regular and non-breaking waves, and a unified oxygen transfer coefficient equation is obtained with consi-deration of the effect of kinetic energy and wave period. An oxygen transfer experiment for the intermediate depth water wave is per-formed to measure the wave parameters and the dissolved oxygen concentration. The experimental data and the least squares method are used to determine the constant in the oxygen transfer coefficient equation. The experimental data and the previous reported data are also used to further validate the oxygen transfer coefficient, and the agreement is satisfactory. The unified equation shows that the oxygen transfer coefficient increases with the increase of a parameter coupled with the wave height and the wave length, but it de-creases with the increase of the wave period, which has a much greater influence on the oxygen transfer coefficient than the coupled parameter.

Evaluation of Oxygen Deficit Stress on Germination Indicators and Seedling

Directory of Open Access Journals (Sweden)

F Hoseini

2012-06-01

Full Text Available To investigate the relationship oxygen deficit stress on germination indicators and seedling growth of five wheat cultivars in laboratory condition, an experiment with Randomized Complete Block design in factorial arrangement with three replications was conducted in 2008. The treatments consisted of five wheat cultivars (Chamran, Flat, Roshan, Stare and Shole as A factor, and two oxygen level (normal seed and seed under oxygen deficit stress conditions as B factor in each of these figures was done. Results showed that oxygen deficit stress caused to decrease for various cultivars germination percentage, germination rate, allometric coefficient, seed vigor index and other germination indicators. Therefore, this test as a suitable method for determining the quality of various seed lot can be used in the water logging condition. In addition, among different cultivars characterized that Roshan cultivar was more resistant to oxygen deficit stress than Chamran, Flat and Star cultivars. Although Chamran cultivar is common cultivar in Khouzestan, but of look most germination indicators arranged as weak seed class. The highest correlation coefficients among the tested cultivars have been related to seed vigor with seedling length and dry weight of radicle with seedling with 0.92 and 0.90, respectively.

Respiratory management of the preterm newborn in the delivery room

Directory of Open Access Journals (Sweden)

Abdel-Hady H

2012-05-01

Full Text Available Hesham Abdel-Hady, Nehad NasefNeonatal Intensive Care Unit, Mansoura University Children's Hospital, Mansoura, EgyptAbstract: The survival of preterm infants has improved significantly during the past several decades. However, bronchopulmonary dysplasia remains a major morbidity. Preterm infants have both structural and functional lung immaturity compared with term infants, making them more likely to require resuscitation and more vulnerable to developing bronchopulmonary dysplasia. Interventions in the delivery room may affect short-term and long-term outcomes for preterm infants. The paradigm of resuscitation of preterm infants has been changing over the past decade from being interventional and invasive to be observational and gentle. Recent developments in respiratory management of preterm infants in the delivery room include oxygen supplementation and monitoring, alveolar recruitment techniques, noninvasive ventilation, new surfactant preparations, and new techniques for administration of surfactant. Providing nasal continuous positive airway pressure (CPAP rather than intubating has been identified as a potentially better practice. Experimental studies have demonstrated that early application of nasal CPAP is protective for the preterm lung and brain compared with mechanical ventilation. Several observational studies have suggested that early nasal CPAP and avoiding intubation leads to reduced oxygen requirements, intubation rates, duration of mechanical ventilation, and may decrease rates of bronchopulmonary dysplasia. Multicenter, randomized controlled trials support the use of nasal CPAP as a primary strategy in preterm babies with respiratory distress syndrome. This approach leads to a reduction in the number of infants who are intubated and given surfactant without an impact on bronchopulmonary dysplasia rates. On the other hand, half of the infants enrolled in these studies failed nasal CPAP treatment. New techniques for surfactant

Women's satisfaction with body image before pregnancy and body mass index 4 years after delivery in the mothers of generation XXI.

Directory of Open Access Journals (Sweden)

Ana Henriques

Full Text Available BACKGROUND: Body image satisfaction (BIS influences body weight regulation and may contribute to long-term healthier lifestyle after pregnancy. Thus, we aimed to assess the association between BIS before pregnancy and body mass index (BMI 4 years after the index pregnancy. METHODS: As part of the follow-up of a birth cohort, 3612 women with prepregnancy BMI >18.5 kg/m(2 were reevaluated 4 years after the birth of a child. BIS was defined as the difference between perceived and ideal body size before pregnancy, assessed by Stunkard Silhouettes after birth. The associations of BIS with BMI change (continuous and BMI classes at 4 years, based on measured weight and height, were estimated using linear and multinomial regression, respectively. RESULTS: Among women with normal prepregnancy BMI, those who felt too small, regarding their ideal, had a 0.25 kg/m(2 smaller increase in BMI within 4 years and a lower likelihood of becoming overweight or obese [multivariate-adjusted odds ratio (OR = 0.63; 95% confidence interval (95%CI: 0.44-0.91 and OR = 0.21; 95%CI: 0.05-0.91, respectively than those satisfied with body image. Feeling too large was associated with a 0.41 kg/m(2 larger increase in BMI and a higher risk of becoming overweight or obese (OR = 2.12; 95%CI:1.73-2.59 and OR = 3.42; 95%CI:2.02-5.79, respectively. A similar, non-significant, trend was observed for overweight women. Obese women who felt too large had a non-significant decrease in BMI. CONCLUSIONS: BIS plays a role in maternal body weight after delivery. Realistic body size goals may promote the motivation to lose weight and contribute to higher success in attaining them.

Postpartum urinary tract infection by mode of delivery: a Danish nationwide cohort study.

Science.gov (United States)

Gundersen, Tina Djernis; Krebs, Lone; Loekkegaard, Ellen Christine Leth; Rasmussen, Steen Christian; Glavind, Julie; Clausen, Tine Dalsgaard

2018-03-14

To examine the association between postpartum urinary tract infection and intended mode of delivery as well as actual mode of delivery. Retrospective cohort study. All live births in Denmark between 2004 and 2010 (n=450 856). Births were classified by intended caesarean delivery (n=45 053) or intended vaginal delivery (n=405 803), and by actual mode of delivery: spontaneous vaginal delivery, operative vaginal delivery, emergency or planned caesarean delivery in labour or prelabour. The primary outcome measure was postpartum urinary tract infection (n=16 295) within 30 days post partum, defined as either a diagnosis of urinary tract infection in the National Patient Registry or redemption of urinary tract infection-specific antibiotics recorded in the Register of Medicinal Product Statistics. We found that 4.6% of women with intended caesarean delivery and 3.5% of women with intended vaginal delivery were treated for postpartum urinary tract infection.Women with intended caesarean delivery had a significantly increased risk of postpartum urinary tract infection compared with women with intended vaginal delivery (OR 1.33, 95% CI 1.27 to 1.40), after adjustment for age at delivery, smoking, body mass index, educational level, gestational diabetes mellitus, infection during pregnancy, birth weight, preterm delivery, preterm prelabour rupture of membranes, pre-eclampsia, parity and previous caesarean delivery (adjusted OR 1.24, 95% CI 1.17 to 1.46).Using actual mode of delivery as exposure, all types of operative delivery had an equally increased risk of postpartum urinary tract infection compared with spontaneous vaginal delivery. Compared with intended vaginal delivery, intended caesarean delivery was significantly associated with a higher risk of postpartum urinary tract infection. Future studies should focus on reducing routine catheterisation prior to operative vaginal delivery as well as improving procedures related to catheterisation. © Article author

Validation of the What Matters Index: A brief, patient-reported index that guides care for chronic conditions and can substitute for computer-generated risk models.

Science.gov (United States)

Wasson, John H; Ho, Lynn; Soloway, Laura; Moore, L Gordon

2018-01-01

Current health care delivery relies on complex, computer-generated risk models constructed from insurance claims and medical record data. However, these models produce inaccurate predictions of risk levels for individual patients, do not explicitly guide care, and undermine health management investments in many patients at lesser risk. Therefore, this study prospectively validates a concise patient-reported risk assessment that addresses these inadequacies of computer-generated risk models. Five measures with well-documented impacts on the use of health services are summed to create a "What Matters Index." These measures are: 1) insufficient confidence to self-manage health problems, 2) pain, 3) bothersome emotions, 4) polypharmacy, and 5) adverse medication effects. We compare the sensitivity and predictive values of this index with two representative risk models in a population of 8619 Medicaid recipients. The patient-reported "What Matters Index" and the conventional risk models are found to exhibit similar sensitivities and predictive values for subsequent hospital or emergency room use. The "What Matters Index" is also reliable: akin to its performance during development, for patients with index scores of 1, 2, and ≥3, the odds ratios (with 95% confidence intervals) for subsequent hospitalization within 1 year, relative to patients with a score of 0, are 1.3 (1.1-1.6), 2.0 (1.6-2.4), and 3.4 (2.9-4.0), respectively; for emergency room use, the corresponding odds ratios are 1.3 (1.1-1.4), 1.9 (1.6-2.1), and 2.9 (2.6-3.3). Similar findings were replicated among smaller populations of 1061 mostly older patients from nine private practices and 4428 Medicaid patients without chronic conditions. In contrast to complex computer-generated risk models, the brief patient-reported "What Matters Index" immediately and unambiguously identifies fundamental, remediable needs for each patient and more sensibly directs the delivery of services to patient categories based on

Urinary incontinence after vaginal delivery or cesarean section.

Science.gov (United States)

Borges, João Bosco Ramos; Guarisi, Telma; Camargo, Ana Carolina Marchesini de; Gollop, Thomaz Rafael; Machado, Rogério Bonassi; Borges, Pítia Cárita de Godoy

2010-06-01

To assess the prevalence of stress urinary incontinence, urge incontinence and mixed urinary incontinence among women residing in the city of Jundiaí (São Paulo, Brazil), and the relation between the type of incontinence and the obstetric history of these women. A cross-sectional community-based study was conducted. A total of 332 women were interviewed; they were seen for whatever reason at the public primary healthcare units of the city of Jundiaí, from March 2005 to April 2006. A pre-tested questionnaire was administered and consisted of questions used in the EPINCONT Study (Epidemiology of Incontinence in the County of Nord-Trondelag). Statistical analysis was carried out using the χ2 test and odds ratio (95%CI). Urinary incontinence was a complaint for 23.5% of the women interviewed. Stress urinary incontinence prevailed (50%), followed by mixed urinary incontinence (35%) and urge incontinence (15%). Being in the age group of 35-64 years, having a body mass index of 30 or greater and having had only vaginal delivery or cesarean section, with uterine contraction, regardless of the number of pregnancies, were factors associated with stress urinary incontinence. However, being in the age group of 55 or older, having a body mass index of 30 or greater and having had three or more pregnancies, only with vaginal deliveries, were factors associated with mixed urinary incontinence. One third of the interviewees complained of some type of urinary incontinence, and half of them presented stress urinary incontinence. Cesarean section, only when not preceded by contractions, was not associated with stress urinary incontinence. The body mass index is only relevant when the stress factor is present.

Effect of hindpaw electrical stimulation on capillary flow heterogeneity and oxygen delivery (Conference Presentation)

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Li, Yuandong; Wei, Wei; Li, Chenxi; Wang, Ruikang K.

2017-02-01

We report a novel use of optical coherence tomography (OCT) based angiography to visualize and quantify dynamic response of cerebral capillary flow pattern in mice upon hindpaw electrical stimulation through the measurement of the capillary transit-time heterogeneity (CTH) and capillary mean transit time (MTT) in a wide dynamic range of a great number of vessels in vivo. The OCT system was developed to have a central wavelength of 1310 nm, a spatial resolution of 8 µm and a system dynamic range of 105 dB at an imaging rate of 92 kHz. The mapping of dynamic cerebral microcirculations was enabled by optical microangiography protocol. From the imaging results, the spatial homogenization of capillary velocity (decreased CTH) was observed in the region of interest (ROI) corresponding to the stimulation, along with an increase in the MTT in the ROI to maintain sufficient oxygen exchange within the brain tissue during functional activation. We validated the oxygen consumption due to an increase of the MTT through demonstrating an increase in the deoxygenated hemoglobin (HbR) during the stimulation by the use of laser speckle contrast imaging.

Singlet oxygen quenching by oxygen in tetraphenyl-porphyrin solutions

International Nuclear Information System (INIS)

Dedic, Roman; Korinek, Miloslav; Molnar, Alexander; Svoboda, Antonin; Hala, Jan

2006-01-01

Time-resolved measurement of singlet oxygen infrared phosphorescence is a powerful tool for determination of quantum yields and kinetics of its photosensitization. This technique was employed to investigate in detail the previously observed effect of singlet oxygen quenching by oxygen. The question whether the singlet oxygen is quenched by oxygen in ground or in excited state was addressed by study of two complementary dependencies of singlet oxygen lifetimes: on dissolved oxygen concentration and on excitation intensity. Oxygen concentration dependence study of meso-tetra(4-sulphonato)phenylporphyrin (TPPS 4 ) phosphorescence kinetics showed linearity of the dependence of TPPS 4 triplet state rate-constant. Corresponding bimolecular quenching constant of (1.5±0.1)x10 9 l/mol s was obtained. On the other hand, rate constants of singlet oxygen depopulation exhibit nonlinear dependence on oxygen concentration. Comparison of zero oxygen concentration-extrapolated value of singlet oxygen lifetime of (6.5±0.4) μs to (3.7±0.1) μs observed under air-saturated conditions indicates importance of the effect of quenching of singlet oxygen by oxygen. Upward-sloping dependencies of singlet oxygen depopulation rate-constant on excitation intensity evidence that singlet oxygen is predominantly quenched by oxygen in excited singlet state

Concanavalin A conjugated biodegradable nanoparticles for oral insulin delivery

Science.gov (United States)

Hurkat, Pooja; Jain, Aviral; Jain, Ashish; Shilpi, Satish; Gulbake, Arvind; Jain, Sanjay K.

2012-11-01

Major research issues in oral protein delivery include the stabilization of protein in delivery devices which could increase its oral bioavailability. The study deals with development of oral insulin delivery system utilizing biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and modifying its surface with Concanavalin A to increase lymphatic uptake. Surface-modified PLGA nanoparticles were characterized for conjugation efficiency of ligand, shape and surface morphology, particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro drug release. Stability of insulin in the developed formulation was confirmed by SDS-PAGE, and integrity of entrapped insulin was assessed using circular dichroism spectrum. Ex vivo study was performed on Wistar rats, which exhibited the higher intestinal uptake of Con A conjugated nanoparticles. In vivo study performed on streptozotocin-induced diabetic rats which indicate that a surface-modified nanoparticle reduces blood glucose level effectively within 4 h of its oral administration. In conclusion, the present work resulted in successful production of Con A NPs bearing insulin with sustained release profile, and better absorption and stability. The Con A NPs showed high insulin uptake, due to its relative high affinity for non-reducing carbohydrate residues i.e., fucose present on M cells and have the potential for oral insulin delivery in effective management of Type 1 diabetes condition.

Concanavalin A conjugated biodegradable nanoparticles for oral insulin delivery

Energy Technology Data Exchange (ETDEWEB)

Hurkat, Pooja; Jain, Aviral; Jain, Ashish; Shilpi, Satish; Gulbake, Arvind; Jain, Sanjay K., E-mail: drskjainin@yahoo.com [Dr. Hari Singh Gour Vishwavidyalaya, Pharmaceutics Research Projects Laboratory, Department of Pharmaceutical Sciences (India)

2012-11-15

Major research issues in oral protein delivery include the stabilization of protein in delivery devices which could increase its oral bioavailability. The study deals with development of oral insulin delivery system utilizing biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles and modifying its surface with Concanavalin A to increase lymphatic uptake. Surface-modified PLGA nanoparticles were characterized for conjugation efficiency of ligand, shape and surface morphology, particle size, zeta potential, polydispersity index, entrapment efficiency, and in vitro drug release. Stability of insulin in the developed formulation was confirmed by SDS-PAGE, and integrity of entrapped insulin was assessed using circular dichroism spectrum. Ex vivo study was performed on Wistar rats, which exhibited the higher intestinal uptake of Con A conjugated nanoparticles. In vivo study performed on streptozotocin-induced diabetic rats which indicate that a surface-modified nanoparticle reduces blood glucose level effectively within 4 h of its oral administration. In conclusion, the present work resulted in successful production of Con A NPs bearing insulin with sustained release profile, and better absorption and stability. The Con A NPs showed high insulin uptake, due to its relative high affinity for non-reducing carbohydrate residues i.e., fucose present on M cells and have the potential for oral insulin delivery in effective management of Type 1 diabetes condition.

Fiber optic refractive index sensor using optofluidic anti-resonant reflecting guidance

Science.gov (United States)

Gao, Ran; Lu, Danfeng; Cheng, Jin; Qi, Zhi-mei

2017-10-01

An optofluidic anti-resonant reflecting guidance has been proposed and experimental demonstrated for the measurement of liquid refractive index. Two micro-channels were fabricated for the delivery of the liquid sample in the hollow core photonic crystal fiber by using femtosecond laser micromachining, serving as an inlet and outlet. The refractive index can be detected by using the resonant condition of the Fabry-Perot resonator, which is interrogated through the wavelength shift and of the lossy dip in the transmission spectrum. The experimental results show that the sensitivity of up to 1328 nm/RIU is achieved for the refractive index in the range from 1.345 to 1.363 RIU, respectively. The proposed sensor appears to have potential applications of precise measurement in chemistry, medicine, and biology.

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

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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.

Nasal high flow therapy: a novel treatment rather than a more expensive oxygen device

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Eleni Ischaki

2017-09-01

Full Text Available Nasal high flow is a promising novel oxygen delivery device, whose mechanisms of action offer some beneficial effects over conventional oxygen systems. The administration of a high flow of heated and humidified gas mixture promotes higher and more stable inspiratory oxygen fraction values, decreases anatomical dead space and generates a positive airway pressure that can reduce the work of breathing and enhance patient comfort and tolerance. Nasal high flow has been used as a prophylactic tool or as a treatment device mostly in patients with acute hypoxaemic respiratory failure, with the majority of studies showing positive results. Recently, its clinical indications have been expanded to post-extubated patients in intensive care or following surgery, for pre- and peri-oxygenation during intubation, during bronchoscopy, in immunocompromised patients and in patients with “do not intubate” status. In the present review, we differentiate studies that suggest an advantage (benefit from other studies that do not suggest an advantage (no benefit compared to conventional oxygen devices or noninvasive ventilation, and propose an algorithm in cases of nasal high flow application in patients with acute hypoxaemic respiratory failure of almost any cause.

Effective photo-enhancement of cellular activity of fluorophore-octaarginine antisense PNA conjugates correlates with singlet oxygen formation, endosomal escape and chromophore lipophilicity

DEFF Research Database (Denmark)

Yarani, Reza; Shiraishi, Takehiko; Nielsen, Peter E.

2018-01-01

Photochemical internalization (PCI) is a cellular drug delivery method based on the generation of light-induced reactive oxygen species (ROS) causing damage to the endosomal membrane and thereby resulting in drug release to the cytoplasm. In our study a series of antisense fluorophore octaarginin...... indicate that efficient photodynamic endosomal escape is strongly dependent on the quantum yield for photochemical singlet oxygen formation, photostability as well as the lipophilicity of the chromophore....

Evaluation of water quality index for River Sabarmati, Gujarat, India

Science.gov (United States)

Shah, Kosha A.; Joshi, Geeta S.

2017-06-01

An attempt has been made to develop water quality index (WQI), using six water quality parameters pH, dissolved oxygen, biochemical oxygen demand, electrical conductivity, nitrate nitrogen and total coliform measured at three different stations along the Sabarmati river basin from the year 2005 to 2008. Rating scale is developed based on the tolerance limits of inland waters and health point of view. Weighted arithmetic water quality index method was used to find WQI along the stretch of the river basin. It was observed from this study that the impact of human activity and sewage disposal in the river was severe on most of the parameters. The station located in highly urban area showed the worst water quality followed by the station located in moderately urban area and lastly station located in a moderately rural area. It was observed that the main cause of deterioration in water quality was due to the high anthropogenic activities, illegal discharge of sewage and industrial effluent, lack of proper sanitation, unprotected river sites and urban runoff.

THE CONDITION INDEX OF MUSSELS (Mytilus galloprovincialis IN BUDAVA AND RAŠA BAY

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Nives Marušić

2009-07-01

Full Text Available Condition index is a factor that can show of some area for shellfish cultivation. Analysis of the condition index from various sites may show importance of these sites for cultivation and shellfish during the year. By monitoring the condition index it is possible to determine dynamic of meat amount change in time. Condition index depends on mussel spawning period, presence of food and changes of environmental factors (temperature, salinity, concentration of dissolved oxygen. The research of condition index was monitored in Budava and Ra{a Bay at depth of 0.5 and 2.5 m. In summer months (July and August when the sea water temperature and salinity were in optimum, the mussel condition index had maximum value. Value of the condition index is proportional with sea temperature and salinity. The condition index of mussels significantly changed over the year period, at different sites (Budava and Raška Bay and at different depth (0.5 and 2.5 m.

The Effect of Oxygen Inhalation Plus Oxytocin Compared with Oxytocin Only on Postpartum Haemorrhage: A Randomized Clinical Trial.

Science.gov (United States)

Suhrabi, Zainab; Taghinejad, Hamid; Direkvand-Moghadam, Ashraf; Akbari, Malihe

2016-09-01

Post Partum Haemorrhage (PPH) is the leading cause of maternal mortality across the world, mainly in the developing countries. The present study was conducted with the aim to investigate effect of oxygen inhalation plus oxytocin compared with oxytocin only on PPH. This study was a clinical trial which was performed in Shahid Mustafa Khomieni Teaching Hospital of Ilam (western Iran) from April 2012 to Nov 2013. One hundred and twenty pregnant women who were referred to delivery ward for normal vaginal delivery were selected with convenience sampling method and they were randomly assigned into two groups. For both groups management of the third stage of labour was done using 1000CC Ringer and 20 units of Oxytocin. In the intervention group, in addition to the routine administration, 8 liters of oxygen via face mask was used continuously until 2 hours after delivery. Blood loss was determined by regular weighing of the buttocks that were previously weighted. The difference was calculated before and after weighing (1 gram increasing of weight was considered to be equivalent to 1CC blood loss). Data were analysed by SPSS 16 version using Student- t and Chi-square tests. The two groups were homogenous in regard to all the base line variables. The study results indicated that the mean of blood loss were (256.16±97) ml at two hours after delivery in the control group and (149.5±46.49) ml in the intervention group. There was a significant difference between PPH of the two groups (poxytocin infusion during 2hours later resulted in a significant decreasing in the amount of bleeding after normal vaginal delivery.

Quantifying the correlation between spatially defined oxygen gradients and cell fate in an engineered three-dimensional culture model.

Science.gov (United States)

Ardakani, Amir G; Cheema, Umber; Brown, Robert A; Shipley, Rebecca J

2014-09-06

A challenge in three-dimensional tissue culture remains the lack of quantitative information linking nutrient delivery and cellular distribution. Both in vivo and in vitro, oxygen is delivered by diffusion from its source (blood vessel or the construct margins). The oxygen level at a defined distance from its source depends critically on the balance of diffusion and cellular metabolism. Cells may respond to this oxygen environment through proliferation, death and chemotaxis, resulting in spatially resolved gradients in cellular density. This study extracts novel spatially resolved and simultaneous data on tissue oxygenation, cellular proliferation, viability and chemotaxis in three-dimensional spiralled, cellular collagen constructs. Oxygen concentration gradients drove preferential cellular proliferation rates and viability in the higher oxygen zones and induced chemotaxis along the spiral of the collagen construct; an oxygen gradient of 1.03 mmHg mm(-1) in the spiral direction induced a mean migratory speed of 1015 μm day(-1). Although this movement was modest, it was effective in balancing the system to a stable cell density distribution, and provided insights into the natural cell mechanism for adapting cell number and activity to a prevailing oxygen regime.

Peptide and protein delivery using new drug delivery systems.

Science.gov (United States)

Jain, Ashish; Jain, Aviral; Gulbake, Arvind; Shilpi, Satish; Hurkat, Pooja; Jain, Sanjay K

2013-01-01

Pharmaceutical and biotechnological research sorts protein drug delivery systems by importance based on their various therapeutic applications. The effective and potent action of the proteins/peptides makes them the drugs of choice for the treatment of numerous diseases. Major research issues in protein delivery include the stabilization of proteins in delivery devices and the design of appropriate target-specific protein carriers. Many efforts have been made for effective delivery of proteins/peptidal drugs through various routes of administrations for successful therapeutic effects. Nanoparticles made of biodegradable polymers such as poly lactic acid, polycaprolactone, poly(lactic-co-glycolic acid), the poly(fumaric-co-sebacic) anhydride chitosan, and modified chitosan, as well as solid lipids, have shown great potential in the delivery of proteins/peptidal drugs. Moreover, scientists also have used liposomes, PEGylated liposomes, niosomes, and aquasomes, among others, for peptidal drug delivery. They also have developed hydrogels and transdermal drug delivery systems for peptidal drug delivery. A receptor-mediated delivery system is another attractive strategy to overcome the limitation in drug absorption that enables the transcytosis of the protein across the epithelial barrier. Modification such as PEGnology is applied to various proteins and peptides of the desired protein and peptides also increases the circulating life, solubility and stability, pharmacokinetic properties, and antigenicity of protein. This review focuses on various approaches for effective protein/peptidal drug delivery, with special emphasis on insulin delivery.

Prostate HDR brachytherapy catheter displacement between planning and treatment delivery

International Nuclear Information System (INIS)

Whitaker, May; Hruby, George; Lovett, Aimee; Patanjali, Nitya

2011-01-01

Background and purpose: HDR brachytherapy is used as a conformal boost for treating prostate cancer. Given the large doses delivered, it is critical that the volume treated matches that planned. Our outpatient protocol comprises two 9 Gy fractions, two weeks apart. We prospectively assessed catheter displacement between CT planning and treatment delivery. Materials and methods: Three fiducial markers and the catheters were implanted under transrectal ultrasound guidance. Metal marker wires were inserted into 4 reference catheters before CT; marker positions relative to each other and to the marker wires were measured from the CT scout. Measurements were repeated immediately prior to treatment delivery using pelvic X-ray with marker wires in the same reference catheters. Measurements from CT scout and film were compared. For displacements of 5 mm or more, indexer positions were adjusted prior to treatment delivery. Results: Results are based on 48 implants, in 25 patients. Median time from planning CT to treatment delivery was 254 min (range 81–367 min). Median catheter displacement was 7.5 mm (range −2.9–23.9 mm), 67% of implants had displacement of 5 mm or greater. Displacements were predominantly caudal. Conclusions: Catheter displacement can occur in the 1–3 h between the planning CT scan and treatment. It is recommended that departments performing HDR prostate brachytherapy verify catheter positions immediately prior to treatment delivery.

Influence of perioperative oxygen fraction on pulmonary function after abdominal surgery: a randomized controlled trial

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Staehr Anne K

2012-07-01

Full Text Available Abstract Background A high perioperative inspiratory oxygen fraction (FiO2 may reduce the frequency of surgical site infection. Perioperative atelectasis is caused by absorption, compression and reduced function of surfactant. It is well accepted, that ventilation with 100% oxygen for only a few minutes is associated with significant formation of atelectasis. However, it is still not clear if a longer period of 80% oxygen results in more atelectasis compared to a low FiO2. Our aim was to assess if a high FiO2 is associated with impaired oxygenation and decreased pulmonary functional residual capacity (FRC. Methods Thirty-five patients scheduled for laparotomy for ovarian cancer were randomized to receive either 30% oxygen (n = 15 or 80% oxygen (n = 20 during and for 2 h after surgery. The oxygenation index (PaO2/FiO2 was measured every 30 min during anesthesia and 90 min after extubation. FRC was measured the day before surgery and 2 h after extubation by a rebreathing method using the inert gas SF6. Results Five min after intubation, the median PaO2/FiO2 was 69 kPa [53-71] in the 30%-group vs. 60 kPa [47-69] in the 80%-group (P = 0.25. At the end of anesthesia, the PaO2/FiO2 was 58 kPa [40-70] vs. 57 kPa [46-67] in the 30%- and 80%-group, respectively (P = 0.10. The median FRC was 1993 mL [1610-2240] vs. 1875 mL [1545-2048] at baseline and 1615 mL [1375-2318] vs. 1633 mL [1343-1948] postoperatively in the 30%- and 80%-group, respectively (P = 0.70. Conclusion We found no significant difference in oxygenation index or functional residual capacity between patients given 80% and 30% oxygen for a period of approximately 5 hours. Trial registration ClinicalTrials.gov Identifier: NCT00637936.

The refractive index of human hemoglobin in the visible range

International Nuclear Information System (INIS)

Zhernovaya, O; Tuchin, V; Sydoruk, O; Douplik, A

2011-01-01

Because the refractive index of hemoglobin in the visible range is sensitive to the hemoglobin concentration, optical investigations of hemoglobin are important for medical diagnostics and treatment. Direct measurements of the refractive index are, however, challenging; few such measurements have previously been reported, especially in a wide wavelength range. We directly measured the refractive index of human deoxygenated and oxygenated hemoglobin for nine wavelengths between 400 and 700 nm for the hemoglobin concentrations up to 140 g l -1 . This paper analyzes the results and suggests a set of model functions to calculate the refractive index depending on the concentration. At all wavelengths, the measured values of the refractive index depended on the concentration linearly. Analyzing the slope of the lines, we determined the specific refraction increments, derived a set of model functions for the refractive index depending on the concentration, and compared our results with those available in the literature. Based on the model functions, we further calculated the refractive index at the physiological concentration within the erythrocytes of 320 g l -1 . The results can be used to calculate the refractive index in the visible range for arbitrary concentrations provided that the refractive indices depend on the concentration linearly.

Mode of delivery after successful external cephalic version: a systematic review and meta-analysis.

Science.gov (United States)

de Hundt, Marcella; Velzel, Joost; de Groot, Christianne J; Mol, Ben W; Kok, Marjolein

2014-06-01

To assess the mode of delivery in women after a successful external cephalic version by performing a systematic review and meta-analysis. We searched MEDLINE, Embase, ClinicalTrials.gov, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library for studies reporting on the mode of delivery in women after successful external cephalic version at term and women with a spontaneous cephalic-presenting fetus. Two reviewers independently selected studies, extracted data, and assessed study quality. The association between mode of delivery and successful external cephalic version was expressed as a common odds ratio with a 95% confidence interval (CI). We identified three cohort studies and eight case-control studies, reporting on 46,641 women. The average cesarean delivery rate for women with a successful external cephalic version was 21%. Women after successful external cephalic version were at increased risk for cesarean delivery for dystocia (odds ratio [OR] 2.2, 95% CI 1.6-3.0), cesarean delivery for fetal distress (OR 2.2, 95% CI 1.6-2.9), and instrumental vaginal delivery (OR 1.4, 95% CI 1.1-1.7). Women who have had a successful external cephalic version for breech presentation are at increased risk for cesarean delivery and instrumental vaginal delivery as compared with women with a spontaneous cephalic presentation. Nevertheless, with a number needed to treat of three, external cephalic version still remains a very efficient procedure to prevent a cesarean delivery.

Decline in arterial partial pressure of oxygen after exercise: a surrogate marker of pulmonary vascular obstructive disease in patients with atrial septal defect and severe pulmonary hypertension.

Science.gov (United States)

Laksmivenkateshiah, Srinivas; Singhi, Anil K; Vaidyanathan, Balu; Francis, Edwin; Karimassery, Sundaram R; Kumar, Raman K

2011-06-01

To examine the utility of decline in arterial partial pressure of oxygen after exercise as a marker of pulmonary vascular obstructive disease in patients with atrial septal defect and pulmonary hypertension. Treadmill exercise was performed in 18 patients with atrial septal defect and pulmonary hypertension. Arterial blood gas samples were obtained before and after peak exercise. A decline in the arterial pressure of oxygen of more than 10 millimetres of mercury after exercise was considered significant based on preliminary tests conducted on the controls. Cardiac catheterisation was performed in all patients and haemodynamic data sets were obtained on room air, oxygen, and a mixture of oxygen and nitric oxide (30-40 parts per million). There were 10 patients who had more than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise and who had a basal pulmonary vascular resistance index of more than 7 Wood units per square metre. Out of eight patients who had less than a 10 millimetres of mercury drop in arterial partial pressure of oxygen after exercise, seven had a basal pulmonary vascular resistance index of less than 7 Wood units per square metre, p equals 0.0001. A decline in arterial partial pressure of oxygen of more than 10 millimetres of mercury predicted a basal pulmonary vascular resistance index of more than 7 Wood units per square metre with a specificity of 100% and a sensitivity of 90%. A decline in arterial partial pressure of oxygen following exercise appears to predict a high pulmonary vascular resistance index in patients with atrial septal defect and pulmonary hypertension. This test is a useful non-invasive marker of pulmonary vascular obstructive disease in this subset.

Noninvasive detection of change in skeletal muscle oxygenation during incremental exercise with near-infrared spectroscopy

Science.gov (United States)

Liu, Fang; Luo, Qingming; Xu, Guodong; Li, Pengcheng

2003-12-01

Near infrared spectroscopy (NIRS) has been developed as a non-invasive method to assess O2 delivery, O2 consumption and blood flow, in diverse local muscle groups at rest and during exercise. The aim of this study was to investigate local O2 consumption in exercising muscle by use of near-infrared spectroscopy (NIRS). Ten elite athletes of different sport items were tested in rest and during step incremental load exercise. Local variations of quadriceps muscles were investigated with our wireless NIRS blood oxygen monitor system. The results show that the changes of blood oxygen relate on the sport items, type of muscle, kinetic capacity et al. These results indicate that NIRS is a potential useful tool to detect local muscle oxygenation and blood flow profiles; therefore it might be easily applied for evaluating the effect of athletes training.

Catalytic Chan–Lam coupling using a ‘tube-in-tube’ reactor to deliver molecular oxygen as an oxidant

Directory of Open Access Journals (Sweden)

Carl J. Mallia

2016-07-01

Full Text Available A flow system to perform Chan–Lam coupling reactions of various amines and arylboronic acids has been realised employing molecular oxygen as an oxidant for the re-oxidation of the copper catalyst enabling a catalytic process. A tube-in-tube gas reactor has been used to simplify the delivery of the oxygen accelerating the optimisation phase and allowing easy access to elevated pressures. A small exemplification library of heteroaromatic products has been prepared and the process has been shown to be robust over extended reaction times.

Gradual reintroduction of oxygen reduces reperfusion injury in cat stomach

International Nuclear Information System (INIS)

Perry, M.A.; Wadhwa, S.S.

1988-01-01

Recent studies have shown that oxygen-derived free radicals are responsible for a major portion of ischemia-reperfusion injury in the stomach. The oxygen radicals are produced during perfusion when oxygen delivery to the tissue increases. In the present study the authors investigate the effect on mucosal injury of regulating the rate of reintroduction of oxygen to the stomach after ischemia. Local gastric ischemia was achieved by reducing celiac artery pressure to 30 mmHg for 1 h. Ischemic injury was assessed by measuring the loss of 51 Cr-labeled red blood cells across the gastric mucosa. Mucosal blood loss was negligible before and during the ischemia period but increased during reperfusion. When blood flow to the stomach was gradually returned to normal after ischemia, the mucosal blood loss was reduced. If the stomach was vascularly perfused with low Po 2 blood for 1 h after ischemia before being returned to normal arterial perfusion, the mucosal blood loss was also reduced. When the stomach was made hypoxemic for 1 h rather than ischemic by perfusing the vasculature with low Po 2 blood then reperfused with normoxic blood, there was very little mucosal bleeding. The data indicate that gastric mucosal bleeding after ischemia is reduced if the tissue is returned slowly to a normal Po 2 . These findings support the concept that reperfusion injury is due largely to the production of oxygen radicals. The low level of injury produced by hypoxemia indicates that hypoxia per se makes only a minor contribution to reperfusion injury in the stomach

The Evolution of Deepwater Dissolved Oxygen in the Northern South China Sea During the Past 400 ka

Science.gov (United States)

Wang, N.; Huang, B.; Dong, Y.

2016-12-01

Reconstruction of dissolved oxygen in paleo-ocean contributes toward understanding the history of ocean circulation, climate, causes of extinctions, and the evolution of marine organisms. Based on analysis of benthic foraminifera oxygen index (BFOI), the redox-sensitive trace elements (Mo/Al), the percentage of epifaunal benthic foraminifera and infaunal/epifaunal ratio at core MD12-3432, we reconstruct the evolution of deep water dissolved oxygen in northern South China Sea (SCS) during the past 400 ka and discuss the mechanisms of variable dissolved oxygen. Both BFOI and Mo/Al are redox indicators. Similar trends confirm that they reflect the variation of dissolved oxygen in seawater since 400 ka accurately. BFOI and Mo/Al indicate that dissolved oxygen was high in MIS 11-MIS 7 and decreased gradually during MIS 6- MIS 2. The percentage of epifauna decreased and infaunal/epifaunal ratio increased with decreasing dissolved oxygen. By comparison of dissolved oxygen and productivity indexes such as phytoplankton total (PT) and species abundances, we found that when PT fluctuated in the average range of 1000-1500 ng/g, the abundances of Bulimina and Uvigerina which represent high productivity increased. However, when PT reached the range of 2500-3000 ng/g, the abundances of Bulimina and Uvigerina didn't increase, but the abundances of dysoxic species Chilostomella oolina and Globobulimina pacifica increased and the dissolved oxygen reached low value. The reasons may be that the decomposition of excessive organic matter consumed more dissolved oxygen. The low dissolved oxygen suppressed the growth of Bulimina and Uvigerina and accelerated the boom of C. oolina and G. oolina. The dissolved oxygen is not only associated with productivity, but also affected by the thermohaline circulation. Benthic foraminifera F. favus is the representative species in Pacific deep water. Its appearance at 194 ka, 205 ka, 325, the 328 ka in MD12-3432 indicate that the upper border of

Mode of delivery and offspring body mass index, overweight and obesity in adult life: a systematic review and meta-analysis.

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Karthik Darmasseelane

Full Text Available BACKGROUND: It has been suggested that mode of delivery, a potentially powerful influence upon long-term health, may affect later life body mass index (BMI. We conducted a systematic review and meta-analysis of the effect of Caesarean section (CS and vaginal delivery (VD on offspring BMI, overweight (BMI>25 and obesity (BMI>30 in adulthood. Secondary outcomes were subgroup analyses by gender and type of CS (in-labour/emergency, pre-labour/elective. METHODS: Using a predefined search strategy, Pubmed, Google Scholar and Web of Science were searched for any article published before 31(st March 2012, along with references of any studies deemed relevant. Studies were selected if they reported birth characteristics and long-term offspring follow-up into adulthood. Aggregate data from relevant studies were extracted onto a pre-piloted data table. A random-effects meta-analysis was carried out in RevMan5. Results are illustrated using forest plots and funnel plots, and presented as mean differences or odds ratios (OR and 95% confidence intervals. RESULTS: Thirty-five studies were identified through the search, and 15 studies with a combined population of 163,796 [corrected] were suitable for inclusion in the meta-analysis. Comparing all CS to VD in pooled-gender unadjusted analyses, mean BMI difference was 0·44 kg·m(-2 (0·17, 0·72; p = 0·002, OR for incidence of overweight was 1·26 (1·16, 1·38; p<0·00001 and OR for incidence of obesity was 1·22 (1·05, 1·42; p = 0·01. Heterogeneity was low in all primary analyses. Similar results were found in gender-specific subgroup analyses. Subgroup analyses comparing type of CS to VD showed no significant impact on any outcome. CONCLUSIONS: There is a strong association between CS and increased offspring BMI, overweight and obesity in adulthood. Given the rising CS rate worldwide there is a need to determine whether this is causal, or reflective of confounding influences. SYSTEMATIC REVIEW

Correction of Oxygen Transport and Metabolic Disturbances in Acute Poisoning by Neurotropic Substances

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G. A. Livanov

2007-01-01

Full Text Available Objective: to examine the capacities of pharmacological correction of impairments in oxygen-transporting systems and metabolic processes with perfluorane and cytoflavin in critically ill patients with acute intoxication with neurotropic poisons.Subjects and methods. Metabolic sequels of severe hypoxia, free radical processes, and endogenous intoxications were studied in 62 patients with the severest acute intoxication with neurotropic poisons.Results. The studies have established that hypoxia and metabolic changes lead to the development of endotoxicosis. Intensifying endotoxicosis in turn enhances hypoxic lesion. Thus, the major task of intensive care is to restore oxygen delivery and to diminish metabolic disturbances and endotoxicosis. Ways of correcting hypoxia and metabolic disturbances are considered in the severe forms of acute poisoning. 

A study of factors influencing surgical cesarean delivery times in an academic tertiary center.

Science.gov (United States)

Gonzalez Fiol, A; Meng, M-L; Danhakl, V; Kim, M; Miller, R; Smiley, R

2018-05-01

Knowledge of hospital-specific average cesarean delivery operative times, and factors influencing length of surgery, can serve as a guide for anesthesiologists when choosing the optimal anesthetic technique. The aim of this study was to determine operative times and the factors influencing those times for cesarean delivery. We conducted a retrospective review of all 1348 cesarean deliveries performed at an academic hospital in 2011. The primary outcome was mean operative time for first, second, third and fourth or more cesarean deliveries. The secondary goal was to identify factors influencing operative time. Variables included age, body mass index, previous surgery, gestational age, urgency of cesarean delivery, anesthesia type, surgeon's seniority, layers closed, and performance of tubal ligation. Mean (standard deviation) operative times for first (n=857), second (n=353), third (n=108) and fourth or more (n=30) cesarean deliveries were 56 (19), 60 (19), 69 (28) and 82 (31) minutes, respectively (P cesarean delivery or the presence of other factors that could increase operative time may warrant catheter-based anesthetic techniques or the addition of adjunctive medications to prolong spinal anesthetic block. Institutional and individual surgeon factors may play an even more important role in determining surgical time. Copyright © 2018 Elsevier Ltd. All rights reserved.

Predictors of shoulder dystocia at the time of operative vaginal delivery.

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Palatnik, Anna; Grobman, William A; Hellendag, Madeline G; Janetos, Timothy M; Gossett, Dana R; Miller, Emily S

2016-11-01

It remains uncertain whether clinical factors known prior to delivery can predict which women are more likely to experience shoulder dystocia in the setting of operative vaginal delivery. We sought to identify whether shoulder dystocia can be accurately predicted among women undergoing an operative vaginal delivery. This was a case-control study of women undergoing a low or outlet operative vaginal delivery from 2005 through 2014 in a single tertiary care center. Cases were defined as women who experienced a shoulder dystocia at the time of operative vaginal delivery. Controls consisted of women without a shoulder dystocia at the time of operative vaginal delivery. Variables previously identified to be associated with shoulder dystocia that could be known prior to delivery were abstracted from the medical records. Bivariable analyses and multivariable logistic regression were used to identify factors independently associated with shoulder dystocia. A receiver operating characteristic curve was created to evaluate the predictive value of the model for shoulder dystocia. Of the 4080 women who met inclusion criteria, shoulder dystocia occurred in 162 (4.0%) women. In bivariable analysis, maternal age, parity, body mass index, diabetes, chorioamnionitis, arrest disorder as an indication for an operative vaginal delivery, vacuum use, and estimated fetal weight >4 kg were significantly associated with shoulder dystocia. In multivariable analysis, parity, diabetes, chorioamnionitis, arrest disorder as an indication for operative vaginal delivery, vacuum use, and estimated fetal weight >4 kg remained independently associated with shoulder dystocia. The area under the curve for the generated receiver operating characteristic curve was 0.73 (95% confidence interval, 0.69-0.77), demonstrating only a modest ability to predict shoulder dystocia before performing an operative vaginal delivery. While risk factors for shoulder dystocia at the time of operative vaginal delivery

Delivery presentations

Science.gov (United States)

Pregnancy - delivery presentation; Labor - delivery presentation; Occiput posterior; Occiput anterior; Brow presentation ... The mother can walk, rock, and try different delivery positions during labor to help encourage the baby ...

Laser-induced generation of singlet oxygen and its role in the cerebrovascular physiology

Science.gov (United States)

Semyachkina-Glushkovskaya, O. V.; Sokolovski, S. G.; Goltsov, A.; Gekaluyk, A. S.; Saranceva, E. I.; Bragina, O. A.; Tuchin, V. V.; Rafailov, E. U.

2017-09-01

For over 55 years, laser technology has expanded from laboratory research to widespread fields, for example telecommunication and data storage amongst others. Recently application of lasers in biology and medicine presents itself as one of the emerging areas. In this review, we will outline the recent advances in using lasers for the generation of singlet oxygen, traditionally used to kill tumour cells or induce thrombotic stroke model due to damage vascular effects. Over the last two decade, completely new results on cerebrovascular effects of singlet oxygen generated during photodynamic therapy (PDT) have been shown alongside promising applications for delivery of drugs and nanoparticles into the brain for therapy of brain cancer. Furthermore, a ;gold key; has been found to overcome the limitations of PDT, such as low light penetration and high toxicity of photosensitizers, by direct generation of singlet oxygen using quantum-dot laser diodes emitting in the near infrared (NIR) spectral range. It is our motivation to highlight these pioneering results in this review, to improve understanding of the biological role of singlet oxygen and to provide new perspectives for improving clinical application of laser based therapy in further research.

Diffusion Limitation and Hyperoxic Enhancement of Oxygen Consumption in Zooxanthellate Sea Anemones, Zoanthids, and Corals.

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Shick, J M

1990-08-01

Depending on their size and morphology, anthozoan polyps and colonies may be diffusion-limited in their oxygen consumption, even under well-stirred, air-saturated conditions. This is indicated by an enhancement of oxygen consumption under steady-state hyperoxic conditions that simulate the levels of O2 produced photosynthetically by zooxanthellae in the hosts' tissues. Such hyperoxia in the tissues of zooxanthellate species negates the effect of the diffusive boundary layer, and increases the rate of oxygen consumption; thus, in many cases, the rate of respiration measured under normoxia in the dark may not be representative of the rate during the day when the zooxanthellae are photosynthesizing and when the supply of oxygen for respiration is in the tissues themselves, not from the environment. These results have implications in respirometric methodology and in calculating the rate of gross photosynthesis in energetic studies. The activity of cytochrome c oxidase is higher in aposymbiotic than in zooxanthellate specimens of the sea anemone Aiptasia pulchella, and this may indicate a compensation for the relative hypoxia in the tissues of the former, enhancing the delivery of oxygen to the mitochondria from the environment.

Progress in the utilization of antenatal and delivery care services in Bangladesh: where does the equity gap lie?

Science.gov (United States)

Pulok, Mohammad Habibullah; Sabah, Md Nasim-Us; Uddin, Jalal; Enemark, Ulrika

2016-07-29

Universal access to health care services does not automatically guarantee equity in the health system. In the post Millennium Development Goals (MDGs) era, the progress towards universal access to maternal health care services in a developing country, like Bangladesh requires an evaluation in terms of equity lens. This study, therefore, analysed the trend in inequity and identified the equity gap in the utilization of antenatal care (ANC) and delivery care services in Bangladesh between 2004 and 2011. The data of this study came from the Bangladesh Demographic and Health Survey. We employed rate ratio, concentration curve and concentration index to examine the trend in inequity of ANC and delivery care services. We also used logistic regression models to analyse the relationship between socioeconomic factors and maternal health care services. The concentration index for 4+ ANC visits dropped from 0.42 in 2004 to 0.31 in 2011 with a greater decline in urban area. There was almost no change in the concentration index for ANC services from medically trained providers during this period. We also found a decreasing trend in inequity in the utilization of both health facility delivery and skilled birth assistance but this trend was again more pronounced in urban area compared to rural area. The concentration index for C-section delivery decreased by about 33 % over 2004-2011 with a similar rate in both urban and rural areas. Women from the richest households were about 3 times more likely to have 4+ ANC visits, delivery at a health facility and skilled birth assistance compared to women from the poorest households. Women's and their husbands' education were significantly associated with greater use of maternal health care services. In addition, women's exposure to mass media, their involvement in microcredit programs and autonomy in healthcare decision-making appeared as significant predictors of using some of these health care services. Bangladesh faces not only a

Mode of delivery after successful external cephalic version: a systematic review and meta-analysis

NARCIS (Netherlands)

de Hundt, Marcella; Velzel, Joost; de Groot, Christianne J.; Mol, Ben W.; Kok, Marjolein

2014-01-01

To assess the mode of delivery in women after a successful external cephalic version by performing a systematic review and meta-analysis. We searched MEDLINE, Embase, ClinicalTrials.gov, Cumulative Index to Nursing and Allied Health Literature, and the Cochrane Library for studies reporting on the

The Role of Relaxation Training to Pregnant Mothers on Health Index of Infants

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SA Mosaviasl

2009-07-01

Full Text Available ABSTRACT: Introduction & Objective: Investigations have shown that the emotional stress during the pregnancy period could have sustainable effects on the embryo. Different factors such as family members, spouse, supporting friends could relive these effects, but coping skills especially relaxation could be more effective on stress. This study was conducted to investigate the effect of relaxation training to pregnant mothers on health index such as Apgar index, weight, height, and cowlick grade in infants. Materials & Methods: This is a clinical trail in which 100 pregnant women who referred to health center of Yasuj (2006-2008 were selected using simple sampling method and assigned randomly to case and control groups. The relaxation was taught to the case group whereas nothing was taught to control groups. At the time of delivery the above mentioned indices were assessed. The gathered data was analyzed using SPSS software. Results: The results showed a significant difference between two groups in weight, height, cephalic index, and colic grade (with better situation in case group. There was no significant difference between two groups in Apgar scores. Conclusion: Considering the results of this study, it seems that teaching of relaxation to pregnant women could be effective in health index of children especially in the time of delivery. Therefore attention should be paid to different methods for reducing the stress in this group of mothers. Keywords: relaxation, pregnant women, infants, Apgar scores

[TRANSPORT OF OXYGEN DURING GEOMETRICAL RECONSTRUCTION OF THE LEFT VENTRICLE IN CONJUNCTION WITH CORONARY ARTERY BYPASS GRAFTING AND USING OF HIGH THORACIC EPIDURAL ANESTHESIA AS A MAJOR COMPONENT OF GENERAL ANAESTHESIA].

Science.gov (United States)

Zatevahina, M V; Farzutdinov, A F; Rahimov, A A; Makrushin, I M; Kvachantiradze, G Y

2015-01-01

The purpose of the study is to examine the perioperative dynamics of strategic blood oxygen transport indicators: delivery (DO2), consumption (VO2), the coefficient of oxygen uptake (CUO2) and their composition, as well as the dynamics of blood lactate indicators in patients with ischaemic heart disease (IHD) who underwent surgery under cardiopulmonary bypass with high thoracic epidural anaesthesia (HTEA) as the main component of anesthesia. Research was conducted in 30 patients with a critical degree of operational risk, during the correction of post-infarction heart aneurysmn using the V. Dor method in combination with coronary artery bypass grafting. The strategic blood oxygen transport indicators (delivery, consumption and the oxygen uptake coefficient) showed a statistically significant decrease compared to the physiological norm and to the initial data at two points of the research: the intubation of the trachea and during cardiopulmonary bypass. The system components of oxygen were influenced at problematic stages by the dynamics of SvO2 (increase), AVD (decrease), hemodilution withe fall of the HIb- in the process of JR in the persence of superficial hypothermia. The maintenance of optimal CA in the context of HTEA, combined with a balanced volemic load and a minimized cardiotonic support ensured the stabilisation of strategic blood oxygen transport indicators aithe postperfusion stage and during the immediate postoperative period The article is dedicated to the study of strategic blood oxygen transport indicators and their components during the operation of geometric reconstruc-tion of the left ventricle combined with coronary artery-bypass using cardiopulmonary bypass and with high thoracic epidural anesthesia as the main component of general anaesthesia. The analysis has covered the stagewise delivery dynamics, consumption and the oxygen uptake coefficient at II stages of the operation and of the immediate postoperative period. The study has ident (fled

Carboxylated nanodiamond and re-oxygenation process of gamma irradiated red blood cells

International Nuclear Information System (INIS)

Acosta-Elias, M.; Sarabia-Sainz, A.; Silva-Campa, E.; Angulo-Molina, A.; Soto-Puebla, D.; Barboza-Flores, M.; Melendrez, R.; Alvarez-Garcia, S.; Pedroza-Montero, M.; Pedroso-Santana, S.; Santacruz-Gomez, K.; Castaneda, B.

2015-01-01

Nanodiamonds (NDs) possess exceptional physical, chemical, and biological properties, which make them suitable for potential biomedical applications. They are biocompatible and their usefulness as effective Raman/fluorescence probes for labeling as well as for drug delivery has been demonstrated. Related to their biocompatibility, the interaction between NDs and red blood cells (RBCs) is of great interest. In this work, the influence of carboxylated NDs (cNDs) in the re-oxygenation capability of both γ-irradiated and stored RBCs was studied. The standard 25 Gy γ dose recommended to prevent transfusion associated graft-versus-host disease was used. A 5-day maximum storage time was used to evaluate the ''storage lesion''. The hemoglobin (Hb) oxygenation state was assessed by Raman microspectroscopy and the morphologic changes on cells were tracked by optical imaging. Our results show that irradiated RBCs have a better re-oxygenation capability and morphological recovery when they are in presence of cNDs. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Carboxylated nanodiamond and re-oxygenation process of gamma irradiated red blood cells

Energy Technology Data Exchange (ETDEWEB)

Acosta-Elias, M. [Doctorado en Nanotecnologia, Universidad de Sonora (Mexico); Sarabia-Sainz, A.; Silva-Campa, E.; Angulo-Molina, A.; Soto-Puebla, D.; Barboza-Flores, M.; Melendrez, R.; Alvarez-Garcia, S.; Pedroza-Montero, M. [Departamento de Investigacion en Fisica, Universidad de Sonora, Hermosillo (Mexico); Pedroso-Santana, S. [Doctorado en Ciencias (Fisica), Universidad de Sonora, Hermosillo (Mexico); Santacruz-Gomez, K.; Castaneda, B. [Departamento de Fisica, Universidad de Sonora, Hermosillo (Mexico)

2015-11-15

Nanodiamonds (NDs) possess exceptional physical, chemical, and biological properties, which make them suitable for potential biomedical applications. They are biocompatible and their usefulness as effective Raman/fluorescence probes for labeling as well as for drug delivery has been demonstrated. Related to their biocompatibility, the interaction between NDs and red blood cells (RBCs) is of great interest. In this work, the influence of carboxylated NDs (cNDs) in the re-oxygenation capability of both γ-irradiated and stored RBCs was studied. The standard 25 Gy γ dose recommended to prevent transfusion associated graft-versus-host disease was used. A 5-day maximum storage time was used to evaluate the ''storage lesion''. The hemoglobin (Hb) oxygenation state was assessed by Raman microspectroscopy and the morphologic changes on cells were tracked by optical imaging. Our results show that irradiated RBCs have a better re-oxygenation capability and morphological recovery when they are in presence of cNDs. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Aerosol delivery and humidification with the Boussignac continuous positive airway pressure device.

Science.gov (United States)

Thille, Arnaud W; Bertholon, Jean-François; Becquemin, Marie-Hélène; Roy, Monique; Lyazidi, Aissam; Lellouche, François; Pertusini, Esther; Boussignac, Georges; Maître, Bernard; Brochard, Laurent

2011-10-01

A simple method for effective bronchodilator aerosol delivery while administering continuing continuous positive airway pressure (CPAP) would be useful in patients with severe bronchial obstruction. To assess the effectiveness of bronchodilator aerosol delivery during CPAP generated by the Boussignac CPAP system and its optimal humidification system. First we assessed the relationship between flow and pressure generated in the mask with the Boussignac CPAP system. Next we measured the inspired-gas humidity during CPAP, with several humidification strategies, in 9 healthy volunteers. We then measured the bronchodilator aerosol particle size during CPAP, with and without heat-and-moisture exchanger, in a bench study. Finally, in 7 patients with acute respiratory failure and airway obstruction, we measured work of breathing and gas exchange after a β(2)-agonist bronchodilator aerosol (terbutaline) delivered during CPAP or via standard nebulization. Optimal humidity was obtained only with the heat-and-moisture exchanger or heated humidifier. The heat-and-moisture exchanger had no influence on bronchodilator aerosol particle size. Work of breathing decreased similarly after bronchodilator via either standard nebulization or CPAP, but P(aO(2)) increased significantly only after CPAP aerosol delivery. CPAP bronchodilator delivery decreases the work of breathing as effectively as does standard nebulization, but produces a greater oxygenation improvement in patients with airway obstruction. To optimize airway humidification, a heat-and-moisture exchanger could be used with the Boussignac CPAP system, without modifying aerosol delivery.

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

Science.gov (United States)

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

2009-01-01

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

water quality index estimate for isiodu river water during dredging in ...

African Journals Online (AJOL)

user

BOD5), dissolved oxygen (DO) ... quality index are fecal coliform count (6.96, 7.57mg/L), BOD5 (3.21, 3.17mg/L) DO (5.47, 5.36mg/L), pH (6.87, 6.86), temperature (13.20 ... Stations A and B are found upstream relative to the dredger position C,.

AICAR Administration Attenuates Hemorrhagic Hyperglycemia and Lowers Oxygen Debt in Anesthetized Male Rabbits.

Science.gov (United States)

Huang, Yi; Ratz, Paul H; Miner, Amy S; Locke, Victoria A; Chen, Grace; Chen, Yang; Barbee, Robert W

2017-01-01

Background: Many strategies have been utilized to treat traumatic shock via improved oxygen delivery (DO 2 ), while fewer have been used to in an attempt to reduce oxygen demand (VO 2 ). The cellular energy sensor 5' adenosine monophosphate-activated protein kinase (AMPK) has the potential to modulate both whole-body DO 2 and VO 2 . Therefore, we determined the effect of the AMPK activator AICAR (5-aminoimidazole-4-carboxamide 1-β-D-ribonucleoside) given acutely or chronically on key metabolites, hemodynamics, and oxygen consumption/delivery before and during hemorrhage in anesthetized male rabbits. Methods: Chronically treated animals received AICAR (40 mg/kg/day, IV) for 10 days prior to hemorrhage, while rabbits in the acute study were infused with AICAR (7.5 mg/kg bolus, 2 mg/kg/min infusion) or vehicle (0.3 ml/kg saline bolus, 0.03 ml/kg/min infusion) IV for 2 h prior to severe hemorrhage. Both acutely and chronically treated animals were sedated (ketamine/xylazine cocktail) the morning of the terminal experiment and surgically prepared for hemorrhage, including the implantation of arterial and venous catheters (for blood removal/sampling and drug/vehicle administration) and thoracotomy for implantation of transit-time flow transducers (for cardiac output determination). Results: AICAR given acutely lowered arterial blood glucose and increased blood lactate levels before hemorrhage, and abolished the well-documented hemorrhage-induced hyperglycemia seen in vehicle treated animals. Animals given AICAR chronically had blunted hemorrhage-induced hyperglycemia without prior baseline changes. Chronically treated AICAR animals showed significantly lower lactate levels during hemorrhage. Rabbits receiving AICAR both acutely and chronically experienced similar falls in mean arterial pressure, cardiac output and hence DO 2 to their vehicle counterparts throughout the hemorrhage period. However, rabbits treated either acutely or chronically with AICAR accumulated lower

AICAR Administration Attenuates Hemorrhagic Hyperglycemia and Lowers Oxygen Debt in Anesthetized Male Rabbits

Directory of Open Access Journals (Sweden)

Yi Huang

2017-09-01

Full Text Available Background: Many strategies have been utilized to treat traumatic shock via improved oxygen delivery (DO2, while fewer have been used to in an attempt to reduce oxygen demand (VO2. The cellular energy sensor 5′ adenosine monophosphate-activated protein kinase (AMPK has the potential to modulate both whole-body DO2 and VO2. Therefore, we determined the effect of the AMPK activator AICAR (5-aminoimidazole-4-carboxamide 1-β-D-ribonucleoside given acutely or chronically on key metabolites, hemodynamics, and oxygen consumption/delivery before and during hemorrhage in anesthetized male rabbits.Methods: Chronically treated animals received AICAR (40 mg/kg/day, IV for 10 days prior to hemorrhage, while rabbits in the acute study were infused with AICAR (7.5 mg/kg bolus, 2 mg/kg/min infusion or vehicle (0.3 ml/kg saline bolus, 0.03 ml/kg/min infusion IV for 2 h prior to severe hemorrhage. Both acutely and chronically treated animals were sedated (ketamine/xylazine cocktail the morning of the terminal experiment and surgically prepared for hemorrhage, including the implantation of arterial and venous catheters (for blood removal/sampling and drug/vehicle administration and thoracotomy for implantation of transit-time flow transducers (for cardiac output determination.Results: AICAR given acutely lowered arterial blood glucose and increased blood lactate levels before hemorrhage, and abolished the well-documented hemorrhage-induced hyperglycemia seen in vehicle treated animals. Animals given AICAR chronically had blunted hemorrhage-induced hyperglycemia without prior baseline changes. Chronically treated AICAR animals showed significantly lower lactate levels during hemorrhage. Rabbits receiving AICAR both acutely and chronically experienced similar falls in mean arterial pressure, cardiac output and hence DO2 to their vehicle counterparts throughout the hemorrhage period. However, rabbits treated either acutely or chronically with AICAR accumulated

Institutional Delivery Service Utilization among Women from Rural Districts of Wolaita and Dawro Zones, Southern Ethiopia; a Community Based Cross-Sectional Study.

Directory of Open Access Journals (Sweden)

Mihiretu Alemayehu Arba

Full Text Available The highest number of maternal deaths occur during labour, delivery and the first day after delivery highlighting the critical need for good quality care during this period. Therefore, for the strategies of institutional delivery to be effective, it is essential to understand the factors that influence individual and household factors to utilize skilled birth attendance and institutions for delivery. This study was aimed to assess factors affecting the utilization of institutional delivery service of women in rural districts of Wolaita and Dawro Zones.A community based cross-sectional study was done among mothers who gave birth within the past one year preceding the survey in Wolaita and Dawro Zones, from February 01 -April 30, 2015 by using a three stage sampling technique. Initially, 6 districts were selected randomly from the total of 17 eligible districts. Then, 2 kebele from each district was selected randomly cumulating a total of 12 clusters. Finally, study participants were selected from each cluster by using systematic sampling technique. Accordingly, 957 mothers were included in the survey. Data was collected by using a pretested interviewer administered structured questionnaire. The questionnaire was prepared by including socio-demographic variables and variables of maternal health service utilization factors. Data was entered using Epi-data version 1.4.4.0 and exported to SPSS version 20 for analysis. Bivariate and multiple logistic regressions were applied to identify candidate and predictor variables respectively.Only 38% of study participants delivered the index child at health facility. Husband's educational status, wealth index, average distance from nearest health facility, wanted pregnancy, agreement to follow post-natal care, problem faced during delivery, birth order, preference of health professional for ante-natal care and maternity care were predictors of institutional delivery.The use of institutional delivery service is

Institutional Delivery Service Utilization among Women from Rural Districts of Wolaita and Dawro Zones, Southern Ethiopia; a Community Based Cross-Sectional Study.

Science.gov (United States)

Arba, Mihiretu Alemayehu; Darebo, Tadele Dana; Koyira, Mengistu Meskele

2016-01-01

The highest number of maternal deaths occur during labour, delivery and the first day after delivery highlighting the critical need for good quality care during this period. Therefore, for the strategies of institutional delivery to be effective, it is essential to understand the factors that influence individual and household factors to utilize skilled birth attendance and institutions for delivery. This study was aimed to assess factors affecting the utilization of institutional delivery service of women in rural districts of Wolaita and Dawro Zones. A community based cross-sectional study was done among mothers who gave birth within the past one year preceding the survey in Wolaita and Dawro Zones, from February 01 -April 30, 2015 by using a three stage sampling technique. Initially, 6 districts were selected randomly from the total of 17 eligible districts. Then, 2 kebele from each district was selected randomly cumulating a total of 12 clusters. Finally, study participants were selected from each cluster by using systematic sampling technique. Accordingly, 957 mothers were included in the survey. Data was collected by using a pretested interviewer administered structured questionnaire. The questionnaire was prepared by including socio-demographic variables and variables of maternal health service utilization factors. Data was entered using Epi-data version 1.4.4.0 and exported to SPSS version 20 for analysis. Bivariate and multiple logistic regressions were applied to identify candidate and predictor variables respectively. Only 38% of study participants delivered the index child at health facility. Husband's educational status, wealth index, average distance from nearest health facility, wanted pregnancy, agreement to follow post-natal care, problem faced during delivery, birth order, preference of health professional for ante-natal care and maternity care were predictors of institutional delivery. The use of institutional delivery service is low in the study

Local cerebral blood flow (1CBF) and oxygen consumption (1CMRO2) in evolving irreversible ischemic infarction: a study with positron tomography and oxygen-15

International Nuclear Information System (INIS)

Baron, J.C.; Rougemont, D.; Lebrun-Grandie, P.; Comar, D.; Bousser, M.G.; Bories, J.; Castaigne, P.; Cabanis, E.

1982-09-01

In 25 patients suffering from cerebral ischemia set up in the area of the internal carotid artery the local cerebral blood flow (lCBF) and local cerebral oxygen consumption (lCMRO 2 ) were measured by the method of continuous inhalation of oxygen 15-labelled gas combined with positron emission tomography. These two local parameters and their ratio, the local oxygen extraction rate (lO 2 E), were studied inside the brain region tending spontaneously towards ischemic necrosis, a zone defined by means of repeated tomodensitometric examinations. The essential facts observed are the variability of the lCBF and the lO 2 E values, from extremely low to extremely high, whereas the collapse of the lCMRO 2 is constant. Consequently this last parameter alone would be a good prognostic index, an lCMRO 2 decrease to a level below about 70% of the controlateral value indicating that the necrosis is spontaneously irreparable. These results are discussed in the light of published data

Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

International Nuclear Information System (INIS)

Choi, Yong Ju; Kim, Young-Jin; Nam, Kyoungphile

2009-01-01

This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

Enhancement of aerobic biodegradation in an oxygen-limiting environment using a saponin-based microbubble suspension

Energy Technology Data Exchange (ETDEWEB)

Choi, Yong Ju; Kim, Young-Jin [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of); Nam, Kyoungphile, E-mail: kpnam@snu.ac.k [Department of Civil and Environmental Engineering, Seoul National University, Shillim-dong, Gwanak-gu, Seoul (Korea, Republic of)

2009-08-15

This study investigated the ability of a saponin-based microbubble suspension to enhance aerobic biodegradation of phenanthrene by subsurface delivery. As the microbubble suspension flowed through a sand column pressure buildup and release was repeatedly observed, which delivered oxygen to the less permeable regions. Burkholderia cepacia RPH1, a phenanthrene-degrading bacterium, was mainly transported in a suspended form in the microbubble suspension. When three pore volumes of the microbubble suspension containing B. cepacia RPH1 was introduced into a column contaminated with phenanthrene (100 mg/kg), the oxygen content declined to 5% from an initial value of 20% within 5 days and correspondingly, 34.4% of initial phenanthrene was removed in 8 days. The addition of two further three pore volumes enhanced the biodegradation efficiency by a factor of 2.2. Our data suggest that a saponin-based microbubble suspension could be a potential carrier for enhancing the aerobic biodegradation under an oxygen-limiting environment. - Microbubble suspension can enhance the phenanthrene biodegradation under an oxygen-limiting condition.

Current application of high flow oxygen nasal cannula in acute hypoxemic respiratory failure in the emergency department

Directory of Open Access Journals (Sweden)

Giulia Bottani

2018-03-01

Full Text Available High flow oxygen with nasal cannula (HFONC is a relatively new mode of oxygen delivery. Advantages of HFONC versus conventional oxygen therapy (COT encompass carbon dioxide washout, generation of a slight positive end-expiratory pressure and maintenance of humidified gas flow through airways. These features are mostly shared with non-invasive mechanical ventilation (NIMV, although with lack of a clearly comparable efficacy. In the last few years, HFONC has gained interest as a third alternative to COT and NIMV in the management of acute hypoxemic respiratory failure in the critically ill patient, both in intensive care units and emergency departments. The aim of this article is to review indications, effects and existing evidence on HFONC, COT and NIMV in the setting of acute hypoxemic respiratory failure.

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

Energy Technology Data Exchange (ETDEWEB)

Herold, S.

1985-03-01

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

Oxygen, climate and the chemical evolution of a 1400 million year old tropical marine setting

DEFF Research Database (Denmark)

Wang, Xiaomei; Zhang, Shuichang; Wang, Huajian

2017-01-01

by oxygenated bottom waters. The transition to unit 3 reflects an increase in primary productivity, and the development of a more biologically active OMZ, that supported anoxygenic phototrophic bacteria. Still, in this unit, the bottom waters remained oxygenated. The overlying unit 2 represents the transition...... for the iron. However, the low organic carbon contents, low hydrogen index (HI) values, and the oxidized nature of the reactive iron pool indicate deposition in oxygenated bottom waters. We interpret unit 4 to represent a low-productivity ferruginous oxygen-minimum zone (OMZ) environment, underlain......The Xiamaling Formation is an exceptionally well-preserved sedimentary succession deposited on a marine passive margin about 1400 million years ago. We used a multi-proxy approach, including iron speciation, trace metal dynamics, and organic geochemistry, to explore the evolution of ocean chemistry...

Trial of labor compared to repeat cesarean section in women with no other risk factors than a prior cesarean delivery

DEFF Research Database (Denmark)

Studsgaard, Anne; Skorstengaard, Malene; Glavind, Julie

2013-01-01

OBJECTIVE: To compare outcomes with trial of labor after cesarean (TOLAC) or elective repeat cesarean delivery on maternal request (ERCD-MR). DESIGN: Prospective cohort study. SETTING: Danish university hospital. POPULATION: Women with TOLAC (n = 1161) and women with ERCD-MR (n = 622) between 2003...... registration of the deliveries. MAIN OUTCOME MEASURES: Adverse neonatal outcomes, risk factors for emergency cesarean, and uterine rupture in case of TOLAC. RESULTS: TOLAC was associated with an increased risk of neonatal depression [odds ratio (OR) 3.6, 95% confidence interval (CI) 1.1-19.1] and neonatal...... vaginal delivery (adjusted OR 1.8, 95% CI 1.1-3.0), index emergency cesarean during labor (adjusted OR 3.0, 95% CI 2.3-4.1), maternal age ≥35 years (adjusted OR 1.9, 95% CI 1.3-2.8), pre-pregnancy body mass index ≥30 (adjusted OR 2.1, 95% CI 1.3-3.3), and birthweight 4000-4499 g (adjusted OR 1.5, 95% CI 1...

Transdermal drug delivery

Science.gov (United States)

Prausnitz, Mark R.; Langer, Robert

2009-01-01

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine. PMID:18997767

Evolution of phenolic compounds and astringency during aging of red wine: effect of oxygen exposure before and after bottling.

Science.gov (United States)

Gambuti, Angelita; Rinaldi, Alessandra; Ugliano, Maurizio; Moio, Luigi

2013-02-27

The aim of this study was to evaluate the effect of oxygen exposure of red wine, before (micro-oxygenation) and after (nano-oxygenation) bottling, on the phenolic composition and astringency of wine. The astringency was evaluated by sensory analysis and by a method based on the SDS-PAGE of salivary proteins after reaction of saliva with wine (SPI, saliva precipitation index). Micro-oxygenation caused a stabilization of color, but this effect disappeared after long aging. For the wine with the lower pH a decrease of wine astringency and SPI was observed 42 months after micro-oxygenation. Oxygen ingress through the closure postbottling was positively correlated with the decrease of SPI. Therefore, the astringency and reactivity of wines toward salivary proteins of a bottled red wine can be modulated by controlled oxygen exposure during aging. For both experiments the effect of oxygen exposure depended on wine composition.

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.

Assisted Vaginal Delivery

Science.gov (United States)

... Education & Events Advocacy For Patients About ACOG Assisted Vaginal Delivery Home For Patients Search FAQs Assisted Vaginal ... Vaginal Delivery FAQ192, February 2016 PDF Format Assisted Vaginal Delivery Labor, Delivery, and Postpartum Care What is ...

An analysis of decrements in vital capacity as an index of pulmonary oxygen toxicity.

Science.gov (United States)

Harabin, A L; Homer, L D; Weathersby, P K; Flynn, E T

1987-09-01

Decrements in vital capacity (% delta VC) were proposed by the Pennsylvania group in the early 1970s as an index of O2-induced lung damage. These workers used the combined effects of PO2 and time of exposure to develop recommendations to limit expected % delta VC. Adopting this general approach, we fitted human pulmonary O2 toxicity data to the hyperbolic equation % delta VC = Bs.(PO2 - B1).(time)B3 using a nonlinear least squares analysis. In addition to the data considered in 1970, our analysis included new data available from the literature. The best fit was obtained when 1) an individual slope parameter, Bs, was estimated for each subject instead of an average slope; 2) PO2 asymptote B1 = 0.38 ATA; and 3) exponent B3 = 1.0. Wide individual variation imposed large uncertainty on any % delta VC prediction. A 12-h exposure to a PO2 of 1 ATA would be expected to yield a median VC decrement of 4%. The 80% confidence limits, however, included changes from +1.0 and -12% delta VC. Until an improved index of pulmonary O2 toxicity is developed, a simplified expression % delta VC = -0.011.(PO2 - 0.5).time (PO2 in ATA and time in min) can be used to predict a median response with little loss in predictability. The limitations of changes in VC as an index are discussed.

Delivery of disulfiram into breast cancer cells using folate-receptor-targeted PLGA-PEG nanoparticles: in vitro and in vivo investigations.

Science.gov (United States)

Fasehee, Hamidreza; Dinarvand, Rassoul; Ghavamzadeh, Ardeshir; Esfandyari-Manesh, Mehdi; Moradian, Hanieh; Faghihi, Shahab; Ghaffari, Seyed Hamidollah

2016-04-21

A folate-receptor-targeted poly (lactide-co-Glycolide) (PLGA)-Polyethylene glycol (PEG) nanoparticle is developed for encapsulation and delivery of disulfiram into breast cancer cells. After a comprehensive characterization of nanoparticles, cell cytotoxicity, apoptosis induction, cellular uptake and intracellular level of reactive oxygen species are analyzed. In vivo acute and chronic toxicity of nanoparticles and their efficacy on inhibition of breast cancer tumor growth is studied. The folate-receptor-targeted nanoparticles are internalized into the cells, induce reactive oxygen species formation, induce apoptosis and inhibit cell proliferation more efficiently compared to the untargeted nanoparticles. The acute and toxicity test show the maximum dose of disulfiram equivalent of nanoparticles for intra-venous injection is 6 mg/kg while show significant decrease in the breast cancer tumor growth rate. It is believed that the developed formulation could be used as a potential vehicle for successful delivery of disulfiram, an old and inexpensive drug, into breast cancer cells and other solid tumors.

Mixed oxygen ion/electron-conducting ceramics for oxygen separation

Energy Technology Data Exchange (ETDEWEB)

Stevenson, J.W.; Armstrong, T.R.; Armstrong, B.L. [Pacific Northwest National Lab., Richland, WA (United States)

1996-08-01

Mixed oxygen ion and electron-conducting ceramics are unique materials that can passively separate high purity oxygen from air. Oxygen ions move through a fully dense ceramic in response to an oxygen concentration gradient, charge-compensated by an electron flux in the opposite direction. Compositions in the system La{sub 1{minus}x}M{sub x}Co{sub 1{minus}y{minus}z}Fe{sub y}N{sub z}O{sub 3{minus}{delta}}, perovskites where M=Sr, Ca, and Ba, and N=Mn, Ni, Cu, Ti, and Al, have been prepared and their electrical, oxygen permeation, oxygen vacancy equilibria, and catalytic properties evaluated. Tubular forms, disks, and asymmetric membrane structures, a thin dense layer on a porous support of the same composition, have been fabricated for testing purposes. In an oxygen partial gradient, the passive oxygen flux through fully dense structures was highly dependent on composition. An increase in oxygen permeation with increased temperature is attributed to both enhanced oxygen vacancy mobility and higher vacancy populations. Highly acceptor-doped compositions resulted in oxygen ion mobilities more than an order of magnitude higher than yttria-stabilized zirconia. The mixed conducting ceramics have been utilized in a membrane reactor configuration to upgrade methane to ethane and ethylene. Conditions were established to balance selectivity and throughput in a catalytic membrane reactor constructed from mixed conducting ceramics.

Prepregnancy body mass index, gestational weight gain, and birth weight in the BRISA cohort

Directory of Open Access Journals (Sweden)

Raina Jansen Cutrim Propp Lima

2018-05-01

Full Text Available ABSTRACT OBJECTIVE To analyze the effects of maternal pre-pregnancy body mass index and weight gain during pregnancy on the baby's birth weight. METHODS We conducted a cross-sectional study with 5,024 mothers and their newborns using a Brazilian birth cohort study. In the proposed model, estimated by structural equation modeling, we tested socioeconomic status, age, marital status, pre-pregnancy body mass index, smoking habit and alcohol consumption during pregnancy, hypertension and gestational diabetes, gestational weight gain, and type of delivery as determinants of the baby's birth weight. RESULTS For a gain of 4 kg/m2 (1 Standard Deviation [SD] in pre-pregnancy body mass index, there was a 0.126 SD increase in birth weight, corresponding to 68 grams (p < 0.001. A 6 kg increase (1 SD in gestational weight gain represented a 0.280 SD increase in newborn weight, correponding to 151.2 grams (p < 0.001. The positive effect of pre-pregnancy body mass index on birth weight was direct (standardized coefficient [SC] = 0.202; p < 0.001, but the negative indirect effect was small (SC = -0.076, p < 0.001 and partially mediated by the lower weight gain during pregnancy (SC = -0.070, p < 0.001. The positive effect of weight gain during pregnany on birth weight was predominantly direct (SC = 0.269, p < 0.001, with a small indirect effect of cesarean delivery (SC = 0.011; p < 0.001. Women with a higher pre-pregnancy body mass index gained less weight during pregnancy (p < 0.001. CONCLUSIONS The effect of gestational weight gain on the increase in birth weight was greater than that of pre-pregnancy body mass index.

A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC)

Energy Technology Data Exchange (ETDEWEB)

Gerard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent; Kafrouni, Hanna; Husson, Francois; Aletti, Pierre [Research Center for Automatic Control (CRAN), Nancy University, CNRS, 54516 Vandoeuvre-les-Nancy (France); Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France) and DOSIsoft SA, 94230 Cachan (France); Research Laboratory for Innovative Processes (ERPI), Nancy University, EA 3767, 5400 Nancy Cedex (France); Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France); DOSIsoft SA, 94230 Cachan (France); Research Center for Automatic Control (CRAN), Nancy University, CNRS, 54516 Vandoeuvre-les-Nancy, France and Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France)

2009-04-15

The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center ({+-}4% of deviation between the calculated and measured doses) by calculating a control process capability (C{sub pc}) index. The C{sub pc} index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should

A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC).

Science.gov (United States)

Gérard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent; Kafrouni, Hanna; Husson, François; Aletti, Pierre

2009-04-01

The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short-term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center (+/- 4% of deviation between the calculated and measured doses) by calculating a control process capability (C(pc)) index. The C(pc) index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short-term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should improve the

Trial of Labor Compared With Cesarean Delivery in Superobese Women.

Science.gov (United States)

Grasch, Jennifer L; Thompson, Jennifer L; Newton, J Michael; Zhai, Amy W; Osmundson, Sarah S

2017-11-01

To examine whether labor compared with planned cesarean delivery is associated with increased maternal and neonatal morbidity. We conducted a retrospective cohort study of all women with body mass indexes (BMIs) at delivery of 50 or greater delivering a live fetus at 34 weeks of gestation of greater between January 1, 2008, and December 31, 2015. Pregnancies with multiple gestations and major fetal anomalies were excluded. The primary outcome was a composite of maternal and neonatal morbidity and was estimated to be 50% in superobese women based on institutional data. A sample size of 338 women determined the study period and was selected to show a 30% difference in the incidence of the primary outcome between the two groups. Multivariate logistic regression adjusted for potential confounders. There were 344 women with BMIs of 50 or greater who met eligibility criteria, of whom 201 (58%) labored and 143 (42%) underwent planned cesarean delivery. Women who labored were younger, more likely to be nulliparous, and less likely to have pre-existing diabetes. Among women who labored, 45% underwent a cesarean delivery, most commonly for labor arrest (61%) or nonreassuring fetal status (28%). Composite maternal and neonatal morbidity was reduced among women who labored even after adjusting for age, parity, pre-existing diabetes, and prior cesarean delivery (adjusted odds ratio 0.42, 95% CI 0.24-0.75). In the subgroup of women (n=234) who underwent a cesarean delivery, whether planned (n=143) or after labor (n=91), there were no differences in maternal and neonatal morbidity except that severe maternal morbidity was increased in women (n=12) who labored (8.8% compared with 2.1%, relative risk 4.2, 95% CI 1.14-15.4). Despite high rates of cesarean delivery in women with superobesity, labor is associated with lower composite maternal and neonatal morbidity. Severe maternal morbidity may be higher in women who require a cesarean delivery after labor.

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

Science.gov (United States)

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

2009-01-01

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

Peptide and low molecular weight proteins based kidney targeted drug delivery systems.

Science.gov (United States)

Xu, Pengfei; Zhang, Hailiang; Dang, Ruili; Jiang, Pei

2018-05-30

Renal disease is a worldwide public health problem, and unfortunately, the therapeutic index of regular drugs is limited. Thus, it is a great need to develop effective treatment strategies. Among the reported strategies, kidney-targeted drug delivery system is a promising method to increase renal efficacy and reduce extra-renal toxicity. In recent years, working as vehicles for targeted drug delivery, low molecular weight proteins (LMWP) and peptide have received immense attention due to their many advantages, such as selective accumulation in kidney, high drug loading capability, control over routes of biodegradation, convenience in modification at the amino terminus, and good biocompatibility. In this review, we describe the current LMWP and peptide carriers for kidney targeted drug delivery systems. In addition, we discuss different linking strategies between carriers and drugs. Furthermore, we briefly outline the current status and attempt to give an outlook on the further study. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

The effects of tumor motion on planning and delivery of respiratory-gated IMRT

International Nuclear Information System (INIS)

Hugo, Geoffrey D.; Agazaryan, Nzhde; Solberg, Timothy D.

2003-01-01

The purpose of this study is to investigate the effects of object motion on the planning and delivery of IMRT. Two phantoms containing objects were imaged using CT under a variety of motion conditions. The effects of object motion on axial CT acquisition with and without gating were assessed qualitatively and quantitatively. Measurements of effective slice width and position for the CT scans were made. Mutual information image fusion was adapted for use as a quantitative measure of object deformation in CT images. IMRT plans were generated on the CT scans of the moving and gated object images. These plans were delivered with motion, with and without gating, and the delivery error between the moving deliveries and a nonmoving delivery was assessed using a scalable vector-based index. Motion during CT acquisition produces motion artifact, object deformation, and object mispositioning, which can be substantially reduced with gating. Objects that vary in cross section in the direction of motion exhibit the most deformation in CT images. Mutual information provides a useful quantitative estimate of object deformation. The delivery of IMRT in the presence of target motion significantly alters the delivered dose distribution in relation to the planned distribution. The utilization of gating for IMRT treatment, including imaging, planning, and delivery, significantly reduces the errors introduced by object motion

Evaluation of recovery and quality of sexual activity in women during postpartum in relation to the different mode of delivery: a retrospective analysis.

Science.gov (United States)

Laganà, A S; Burgio, M A; Ciancimino, L; Sicilia, A; Pizzo, A; Magno, C; Butticè, S; Triolo, O

2015-08-01

Aim of the study was to assess the recovery and quality of sexual activity of women during postpartum, in relation to delivery. We recruited 200 women at 8 weeks after delivery. For each patient we recorded mode of delivery, age, body mass index (BMI), parity and test Female Sexual Function Index (FSFI) score. Sixty-four women (32%) had spontaneous deliveries without episiotomy, 48 (24%) had it with episiotomy, 88 (44%) had caesarean sections. The analysis of variance (ANOVA) test showed no significant differences among the 3 groups for age, BMI, parity. The test FSFI evidenced 68 cases (34%) of Regular Female Sexual Function (RFSF) and 132 (66%) of Female Sexual Dysfunction (FSD). The ANOVA test showed significant differences among the 3 groups in RFSF (F [2, 14]=8.075, P=0.005), but not in FSD (F [2, 30]=2.646, P=0.087). In RFSF, FSFI score was higher in women who had vaginal delivery with episiotomy compared with the other two groups. Conversely, in FSD (both with or without resumed sexual activity at 8 weeks postpartum) we evidenced that patients who had vaginal delivery with episiotomy showed lower FSFI score than the other two groups, with a decrease in lubrication, orgasm and satisfaction scores. Furthermore, we observed that most of the RFSF patients had a job and breastfed. Our results did not evidence a direct and significant correlation between mode of delivery and onset of female postpartum sexual dysfunction, even if FSD patients who underwent episiotomy during delivery markedly showed low FSFI scores.

Reviewing Sexual Function After Delivery and Its Association with Some of the Demographic Marital Satisfaction Factors

Directory of Open Access Journals (Sweden)

Kh. Broumandfar

2012-04-01

Full Text Available Background: Desirable sexual function has an important role in strengthening the marital life of the couples. Sexual disorders can cause mental pressure and affect quality of life and marital relationship. Methods: This was a descriptive correlation study in one group and one phase covering multivariables. The study sample included 384 women after delivery period that had the following inclusion criteria: the age of at least 18 years, delivery in 38-42 pregnancy weeks, primiparous and multiparous women, living in the city, single pregnancy, and twelve months elapsed from the delivery. The required data such demographic, marital satisfaction and sexual function index were collected through reporting questionnaire. The data were analyzed using descriptive and inferential statistical methods using software SPSS. Results: The findings of the study indicated that the most prevalent disorder of the sexual relationship in postpartum was dyspareunia and the least prevalent was the sexual desire. There was no significant association between sexual function and, age, education degree , body mass index ,body size and job, but there was a significant association for other factors such as the economic, residence and marital satisfaction (p<0.01. Conclusion: It is recommended that sexual problems after delivery be placed on the list of health teaching issues to pass easily this period of time. Women should be assured that these problems gradually would be improved and they should learn using proper techniques to decrease dyspareunia which is a sexual disorder in postpartum period.

Voluntary exercise confers protection against age-related deficits in brain oxygenation in awake mice model of Alzheimer's disease

Science.gov (United States)

Lu, Xuecong; Moeini, Mohammad; Li, Baoqiang; Sakadžić, Sava; Lesage, Frédéric

2018-02-01

Alzheimer's disease (AD) is a neurodegenerative disease characterized by short-term memory loss and cognitive inabilities. This work seeks to study the effects of voluntary exercise on the change in oxygen delivery in awake mice models of Alzheimer's disease by monitoring brain tissue oxygenation. Experiments were performed on Young (AD_Y, 3-4 months, n=8), Old (AD_O, 6-7 months, n=8), and Old with exercise (AD_OEX, 6-7 months, n=8) transgenic APPPS1 mice and their controls. Brain tissue oxygenation was measured by two photon phosphorescence lifetime microscopy on the left sensory motor cortex. We found that the average tissue PO2 decreased with age but were regulated by exercise. The results suggest a potential for exercise to improve brain function with age and AD.

Effects of oxygen delivery, dietary nitrate, intensified training and prior exercise on oxygen uptake kinetics and performance in humans

DEFF Research Database (Denmark)

Christensen, Peter Møller

benefits from supplementing with nitrate to improve exercise efficiency and performance in endurance trained subjects. Furthermore it appears difficult to improve VO2 kinetics with intensified training in trained athletes; however intense exercise can amplify the VO2 response during subsequent high......In response to an increase in the metabolic demand the oxygen uptake (VO2) increases in an exponential fashion in exercising muscles and stabilizes after 1-2 min eventually reaching a plateau or steady state where the energy demand is matched by the l vel of VO2. VO2 kinetics describes the distinct...... phases of the VO2 response at the onset of exercise. Fast VO2 kinetics are considered to be beneficial in intense endurance sports with competitions lasting ~2-8 min, whereas low VO2 at steady state (high efficiency) is considered beneficial especially in events of longer duration. To improve...

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

Science.gov (United States)

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

2015-09-01

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

Self-nanoemulsifying drug delivery systems for oral insulin delivery

DEFF Research Database (Denmark)

Li, Ping; Tan, Angel; Prestidge, Clive A

2014-01-01

This study aims at evaluating the combination of self-nanoemulsifying drug delivery systems (SNEDDS) and enteric-coated capsules as a potential delivery strategy for oral delivery of insulin. The SNEDDS preconcentrates, loaded with insulin-phospholipid complex at different levels (0, 2.5 and 10% w...

Prognostic value of brachioradialis muscle oxygen saturation index and vascular occlusion test in septic shock patients.

Science.gov (United States)

Marín-Corral, J; Claverias, L; Bodí, M; Pascual, S; Dubin, A; Gea, J; Rodriguez, A

2016-05-01

To compare rSO2 (muscle oxygen saturation index) static and dynamic variables obtained by NIRS (Near Infrared Spectroscopy) in brachioradialis muscle of septic shock patients and its prognostic implications. Prospective and observational study. Intensive care unit. Septic shock patients and healthy volunteers. The probe of a NIRS device (INVOS 5100) was placed on the brachioradialis muscle during a vascular occlusion test (VOT). Baseline, minimum and maximum rSO2 values, deoxygenation rate (DeOx), reoxygenation slope (ReOx) and delta value. Septic shock patients (n=35) had lower baseline rSO2 (63.8±12.2 vs. 69.3±3.3%, p<0.05), slower DeOx (-0.54±0.31 vs. -0.91±0.35%/s, p=0.001), slower ReOx (2.67±2.17 vs. 9.46±3.5%/s, p<0.001) and lower delta (3.25±5.71 vs. 15.1±3.9%, p<0.001) when compared to healthy subjects (n=20). Among septic shock patients, non-survivors showed lower baseline rSO2 (57.0±9.6 vs. 69.8±11.3%, p=0.001), lower minimum rSO2 (36.0±12.8 vs. 51.3±14.8%, p<0.01) and lower maximum rSO2 values (60.6±10.6 vs. 73.3±11.2%, p<0.01). Baseline rSO2 was a good mortality predictor (AUC 0.79; 95%CI: 0.63-0.94, p<0.01). Dynamic parameters obtained with VOT did not improve the results. Septic shock patients present an important alteration of microcirculation that can be evaluated by NIRS with prognostic implications. Monitoring microvascular reactivity in the brachioradialis muscle using VOT with our device does not seem to improve the prognostic value of baseline rSO2. Copyright © 2015 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Transdermal drug delivery

OpenAIRE

Prausnitz, Mark R.; Langer, Robert

2008-01-01

Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability ...

Gastric injury induced by hemorrhage, local ischemia, and oxygen radical generation

International Nuclear Information System (INIS)

Wadhwa, S.S.; Perry, M.A.

1987-01-01

Gastric mucosal injury caused by local intra-arterial generation of oxygen-derived free radicals was compared with gastric injury caused by 30 min of hemorrhage-induced ischemia or local ischemia. The index of injury was the loss of 51 Cr-labeled red cells across the gastric mucosa. Generation of oxygen radicals in the celiac artery caused a rapid increase in mucosal blood loss during the period of radical generation, and this loss was maintained after radical production ceased. Local ischemia produced similar mucosal injury; however, this occurred after reperfusion of the stomach and not during the ischemic episode. Hemorrhage-induced ischemia produced a threefold greater mucosal blood loss than local ischemia. The results of this study indicate that (1) oxygen radicals generated enzymatically in the blood supply to the stomach cause mucosal bleeding of similar magnitude to that observed after local ischemia and (2) that gastric ischemia induced by systemic hypotension produces more severe gastric injury than the same level of local hypotension

Validation of a novel device to objectively measure adherence to long-term oxygen therapy

Directory of Open Access Journals (Sweden)

Sun-Kai V Lin

2008-10-01

Full Text Available Sun-Kai V Lin1, Daniel K Bogen1, Samuel T Kuna2,31Department of Bioengineering; 2Department of Medicine, Pulmonary, Allergy and Critical Care Division, and Center for Sleep and Respiratory Neurobiology, University of Pennsylvania, Pennsylvania, USA; 3Department of Medicine, Philadelphia Veterans Affairs Medical Center Philadelphia, Pennsylvania, USARationale: We have developed a novel oxygen adherence monitor that objectively measures patient use of long-term oxygen therapy. The monitor attaches to the oxygen source and detects whether or not the patient is wearing the nasal cannula.Objective: The study’s purpose was to validate the monitor’s performance in patients with chronic obstructive pulmonary disease during wakefulness and sleep.Methods: Ten adult males with stable chronic obstructive pulmonary disease (mean ± SD FEV1 37.7 ± 14.9% of predicted on long-term continuous oxygen therapy were tested in a sleep laboratory over a 12–13 hour period that included an overnight polysomnogram.Measurements: The monitor’s measurements were obtained at 4-minute intervals and compared to actual oxygen use determined by review of time-synchronized video recordings.Main results: The monitor made 1504/1888 (79.7% correct detections (unprocessed data across all participants: 957/1,118 (85.6% correct detections during wakefulness and 546/770 (70.9% during sleep. All errors were false negatives, ie, the monitor failed to detect that the participant was actually wearing the cannula. Application of a majority-vote filter to the raw data improved overall detection accuracy to 84.9%.Conclusions: The results demonstrate the monitor’s ability to objectively measure whether or not men with chronic obstructive pulmonary disease are receiving their oxygen treatment. The ability to objectively measure oxygen delivery, rather than oxygen expended, may help improve the management of patients on long-term oxygen therapy.Keywords: chronic obstructive pulmonary

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.

High-Energy-Density Metal-Oxygen Batteries: Lithium-Oxygen Batteries vs Sodium-Oxygen Batteries.

Science.gov (United States)

Song, Kyeongse; Agyeman, Daniel Adjei; Park, Mihui; Yang, Junghoon; Kang, Yong-Mook

2017-12-01

The development of next-generation energy-storage devices with high power, high energy density, and safety is critical for the success of large-scale energy-storage systems (ESSs), such as electric vehicles. Rechargeable sodium-oxygen (Na-O 2 ) batteries offer a new and promising opportunity for low-cost, high-energy-density, and relatively efficient electrochemical systems. Although the specific energy density of the Na-O 2 battery is lower than that of the lithium-oxygen (Li-O 2 ) battery, the abundance and low cost of sodium resources offer major advantages for its practical application in the near future. However, little has so far been reported regarding the cell chemistry, to explain the rate-limiting parameters and the corresponding low round-trip efficiency and cycle degradation. Consequently, an elucidation of the reaction mechanism is needed for both lithium-oxygen and sodium-oxygen cells. An in-depth understanding of the differences and similarities between Li-O 2 and Na-O 2 battery systems, in terms of thermodynamics and a structural viewpoint, will be meaningful to promote the development of advanced metal-oxygen batteries. State-of-the-art battery design principles for high-energy-density lithium-oxygen and sodium-oxygen batteries are thus reviewed in depth here. Major drawbacks, reaction mechanisms, and recent strategies to improve performance are also summarized. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Oxygen Therapy

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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.

Contribution of Respiratory Muscle Oxygen Consumption to Breathing Limitation and Cyspnea

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Pere Casan

1997-01-01

Full Text Available During exercise, the sustainable activity of large muscle groups is limited by oxygen delivery. The purpose of this study was to see whether the oxygen consumption of the respiratory muscles reaches a similar critical value under maximal resistive loading and hyperventilation. A secondary objective was to see whether dyspnea (estimated discomfort experienced with breathing using the Borg 0-10 scale and the oxygen consumption of the respiratory muscles are closely related across conditions. This would be expected if intramuscular sensory nerve fibres stimulated as a consequence of metabolic events contributed to this sensation. In six normal subjects the respiratory muscles were progressively activated by the addition of incremental inspiratory resistive loads to a maximum of 300 cm H20×s/L (SD=66.4, and incremental dead space to a maximum of 2638 mL (SD=452, associated with an increase in ventilation to 75.1 L/min (SD=29.79. Each increment was maintained for 5 mins to allow the measurement of oxygen uptake in a steady state. During resistive loading total oxygen consumption increased from 239 mL/min (SD=38.2 to 299 mL/min (SD=52.3 and dyspnea increased to "very severe" (Borg scale 7.5, SD=1.55. During dead space loading total oxygen consumption increased from 270 mL/min (SD=20.2 to 426 mL/min (SD=81.9 and dyspnea increased to "very severe" (7.1, SD=0.66. Oxygen cost of inspiratory muscle power was 25 mL/watt (95% confidence limits 16.7 to 34.3 with dead space loading and 91 mL/watt (95% confidence limits 54 to 128 with resistive loading. Oxygen consumption did not reach a critical common value in the two types of loading, 60 mL/min (SD 22.3 during maximal resistive loading and 156 mL/min (SD 82.4 during maximal dead space loading (P<0.05. Physiological factors limiting the respiratory muscles are not uniquely related to oxygen consumption and appear to be expressed through the activation of sensory structures, perceptually manifested as

Noninvasive determination of myocardial blood flow, oxygen consumption and efficiency in normal humans by carbon-11 acetate positron emission tomography imaging

International Nuclear Information System (INIS)

Porenta, G.; Cherry, S.; Czernin, J.; Brunken, R.; Kuhle, W.; Hashimoto, T.; Schelbert, H.R.

1999-01-01

The aims of this study were: (1) to measure noninvasively and near simultaneously myocardial blood flow, oxygen consumption, and contractile function and (2) to analyze myocardial energy expenditure and efficiency at rest and during dobutamine stress in normal humans. Dynamic and gated carbon-11 acetate positron emission tomography (PET) imaging was performed in 11 normal subjects. The initial uptake of 11 C-acetate was measured to estimate myocardial blood flow. Oxygen consumption was derived from the monoexponential slope of the 11 C-clearance curve recorded during myocardial washout. ECG-gated systolic and diastolic images were acquired during the peak myocardial 11 C activity to measure left ventricular radius, myocardial wall thickness, and long axis length. Myocardial oxygen consumption and parameters of cardiac geometry were used to determine myocardial energetics and cardiac efficiency by tension-area area analysis. Myocardial blood flow averaged 0.8±0.06 ml min -1 g -1 at rest and 1.48±0.15 ml min -1 g -1 during dobutamine stress. Oxygen delivery and consumption were 151±13 and 88±15 μl O 2 min -1 g -1 at rest and increased to 291±31 and 216±31 μl O 2 min -1 g -1 , respectively, during pharmacological stress (P 11 C acetate imaging provides the unique capability to study noninvasively determinants of myocardial energy delivery, expenditure, and efficiency. (orig.)

Tools for the development of a benthic quality index for Italian lakes

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Angelo SOLIMINI

2006-02-01

Full Text Available In this paper, we propose a methodology to develop a benthic quality index useful for Italian lakes. The existing data about benthic macroinvertebrates of the Italian lakes were collected over a period of 50 years, but only a few lakes such as the Maggiore and the Mergozzo have been intensely studied. Some large lakes such as Lake Como are still almost uninvestigated. In total, 570 benthic macroinvertebrate taxa were identified; of which 373 belong to Chironomidae and 85 to Oligochaeta. With the aim of relating environmental variables with macrobenthos assemblages, we carried out a canonical correlation analysis (CANON using a database that included 1060 sampling points. Both environmental (13 variables describing morphometry and hydrochemistry and biological data (57 taxa were available, but only taxa present in at least 10 samples were selected for data analysis. Three canonical variates were ecologically significant. The first one was correlated with conductivity, pH and alkalinity and accounted for 20% of the total variation. The second one was positively correlated with total phosphorus and N-NH4, and inversely with dissolved oxygen, and accounted for 18% of the total variation. The third one showed a direct correlation with maximum lake depth and volume and an inverse correlation with water temperature, and accounted for 17% of the total variation. A Trophic Status Index (TSI, based on the table 11 of the Italian Law 152/99 (without including chlorophyll, was calculated by ranking percent oxygen saturation, transparency and total phosphorus. TSI was used to test a Benthic Quality Index for Italian Lakes (BQIL which is proposed in the present paper. The algorithm considered three steps. First, the means of three variables were calculated: percent oxygen saturation, transparency and total phosphorus weighted by the taxa abundances. These values are interpreted as optimum for each taxon and used to assign an indicator weight (BQIW. Second

Serum triiodothyronine and free triiodothyronine index in normal pregnancy

International Nuclear Information System (INIS)

Karunanidhi, A.; Charles, S.X.; Kanagasabapathy, A.S.

1981-01-01

The thyroid function at various stages of pregnancy and after delivery was assessed by measuring serum total triiodothyronine (T 3 ), T 3 resin uptake (T 3 RU) and free triiodothyronine index (FT 3 I). In first, second and third trimesters of pregnancy, the mean values of serum total T 3 were significantly elevated (P 3 I remained unaltered. During labour, both serum total T 3 and FT 3 I observed during labour and after delivery may be due to the changes in blood oestrogen levels. This study indicates that serum free T 3 concentrations in pregnancy remained unaltered in the presence of elevated serum total T 3 levels. FT 3 I determination would thus appear to be a reliable in vitro thyroid function test for the assessment of thyroid function throughout pregnancy. Serum total T 3 was measured by radioimmunoassay using radioiodinated T 3 ( 125 I-T 3 ). (author)

Oxygen therapy - infants

Science.gov (United States)

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

Optofluidic refractive index sensor based on partial reflection

Science.gov (United States)

Zhang, Lei; Zhang, Zhang; Wang, Yichuan; Ye, Meiying; Fang, Wei; Tong, Limin

2017-06-01

We demonstrate a novel optofluidic refractive index (RI) sensor with high sensitivity and wide dynamic range based on partial reflection. Benefited from the divergent incident light and the output fibers with different tilting angles, we have achieved highly sensitive RI sensing in a wide range from 1.33 to 1.37. To investigate the effectiveness of this sensor, we perform a measurement of RI with a resolution of ca. 5.0×10-5 refractive index unit (RIU) for ethylene glycol solutions. Also, we have measured a series of liquid solutions by using different output fibers, achieving a resolution of ca. 0.52 mg/mL for cane surge. The optofluidic RI sensor takes advantage of the high sensitivity, wide dynamic range, small footprint, and low sample consumption, as well as the efficient fluidic sample delivery, making it useful for applications in the food industry.

Instrumented impact properties of zircaloy-oxygen and zircaloy-hydrogen alloys

Energy Technology Data Exchange (ETDEWEB)

Garde, A.M.; Kassner, T.F.

1980-04-01

Instrumented-impact tests were performed on subsize Charpy speciments of Zircaloy-2 and -4 with up to approx. 1.3 wt % oxygen and approx. 2500 wt ppM hydrogen at temperatures between 373 and 823/sup 0/K. Self-consistent criteria for the ductile-to-brittle transition, based upon a total absorbed energy of approx. 1.3 x 10/sup 4/ J/m/sup 2/, a dynamic fracture toughness of approx. 10 MPa.m/sup 1/2/, and a ductility index of approx. 0, were established relative to the temperature and oxygen concentration of the transformed BETA-phase material. The effect of hydrogen concentration and hydride morphology, produced by cooling Zircaloy-2 specimens through the temperature range of the BETA ..-->.. ..cap alpha..' = hydride phase transformation at approx. 0.3 and 3 K/s, on the impact properties was determined at temperatures between 373 and 673 K. On an atom fraction basis, oxygen has a greater effect than hydrogen on the impact properties of Zircaloy at temperatures between approx. 400 and 600 K. 34 figures.

Effects of levosimendan on glomerular filtration rate, renal blood flow, and renal oxygenation after cardiac surgery with cardiopulmonary bypass: a randomized placebo-controlled study.

Science.gov (United States)

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2013-10-01

Acute kidney injury develops in a large proportion of patients after cardiac surgery because of the low cardiac output syndrome. The inodilator levosimendan increases cardiac output after cardiac surgery with cardiopulmonary bypass, but a detailed analysis of its effects on renal perfusion, glomerular filtration, and renal oxygenation in this group of patients is lacking. We therefore evaluated the effects of levosimendan on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen demand/supply relationship, i.e., renal oxygen extraction, early after cardiac surgery with cardiopulmonary bypass. Prospective, placebo-controlled, and randomized trial. Cardiothoracic ICU of a tertiary center. Postcardiac surgery patients (n=30). The patients were randomized to receive levosimendan, 0.1 µg/kg/min after a loading dose of 12 µg/kg (n=15), or placebo (n=15). The experimental procedure started 4-6 hours after surgery in the ICU during propofol sedation and mechanical ventilation. Systemic hemodynamic were evaluated by a pulmonary artery thermodilution catheter. Renal blood flow and glomerular filtration rate were measured by the renal vein retrograde thermodilution technique and by renal extraction of Cr-EDTA, respectively. Central venous pressure was kept constant by colloid/crystalloid infusion. Compared to placebo, levosimendan increased cardiac index (22%), stroke volume index (15%), and heart rate (7%) and decreased systemic vascular resistance index (21%), whereas mean arterial pressure was not affected. Levosimendan induced significant increases in renal blood flow (12%, prenal vascular resistance (18%, prenal oxygen consumption, or renal oxygen extraction, compared to placebo. After cardiac surgery with cardiopulmonary bypass, levosimendan induces a vasodilation, preferentially of preglomerular resistance vessels, increasing both renal blood flow and glomerular filtration rate without jeopardizing renal oxygenation. Due to its

Effect of rehabilitation training combined with hyperbaric oxygen therapy on the nerve cytokine secretion and oxidative stress in rehabilitation period of patients with cerebral infarction

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Ling Kong

2017-11-01

Full Text Available Objective: To discuss the influence of rehabilitation training combined with hyperbaric oxygen therapy on the nerve cytokine secretion and oxidative stress in rehabilitation period of patients with cerebral infarction. Methods: A total of 110 patients with cerebral infarction who received rehabilitation therapy in the hospital between January 2015 and May 2017 were divided into routine group (n=55 and hyperbaric oxygen group (n=55 according to random number table. Routine group received regular rehabilitation training, and hyperbaric oxygen group underwent rehabilitation training combined with hyperbaric oxygen therapy. The differences in the serum contents of nerve factors, neurotransmitters and oxidative stress indexes were compared between the two groups at immediately after admission (T0 and after 14 d of treatment (T1. Results: At T0, there was no statistically significant difference in the serum contents of nerve factors, neurotransmitters and oxidative stress indexes between the two groups. At T1, serum nerve factors MBP and NSE contents of hyperbaric oxygen group were lower than those of routine group while NGF content was higher than that of routine group; serum neurotransmitter Glu content was lower than that of routine group while GABA content was higher than that of routine group; serum oxidative stress indexes ROS and LHP contents were lower than those of routine group while CAT and SOD contents were higher than those of routine group. Conclusion: Rehabilitation training combined with hyperbaric oxygen therapy can effectively optimize the nerve function and inhibit the systemic oxidative stress response in rehabilitation period of patients with cerebral infarction.

Regional oxygen saturation index (rSO2) in brachioradialis and deltoid muscle. Correlation and prognosis in patients with respiratory sepsis.

Science.gov (United States)

Rodríguez, A; Claverias, L; Marín, J; Magret, M; Rosich, S; Bodí, M; Trefler, S; Pascual, S; Gea, J

2015-03-01

To compare oxygen saturation index (rSO2) obtained simultaneously in two different brachial muscles. Prospective and observational study. Intensive care unit. Critically ill patients with community-acquired pneumonia. Two probes of NIRS device (INVOS 5100) were simultaneously placed on the brachioradialis (BR) and deltoid (D) muscles. rSO2 measurements were recorded at baseline (ICU admission) and at 24h. Demographic and clinical variables were registered. Pearson's correlation coefficient was used to assess the association between continuous variables. The consistency of the correlation was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman plot. The predictive value of the rSO2 for mortality was calculated by ROC curve. Nineteen patients were included with an ICU mortality of 21.1%. The rSO2 values at baseline and at 24h were significantly higher in D than in BR muscle. Values obtained simultaneously in both limbs showed a strong correlation and adequate consistency: BR (r=0.95; p0.001) but a wide limit of agreement. Non-survivors had rSO2 values significantly lower than survivors at all times of the study. No patient with rSO2 >60% in BR died, and only 17.6% died with an rSO2 value >60% in D. Both muscles showed consistent discriminatory power for mortality. Both BR and D muscles were appropriate for measuring rSO2. Copyright © 2013 Elsevier España, S.L.U. and SEMICYUC. All rights reserved.

Improved Intratumoral Oxygenation Through Vascular Normalization Increases Glioma Sensitivity to Ionizing Radiation

International Nuclear Information System (INIS)

McGee, Mackenzie C.; Hamner, J. Blair; Williams, Regan F.; Rosati, Shannon F.; Sims, Thomas L.; Ng, Catherine Y.; Gaber, M. Waleed; Calabrese, Christopher; Wu Jianrong; Nathwani, Amit C.; Duntsch, Christopher; Merchant, Thomas E.; Davidoff, Andrew M.

2010-01-01

Purpose: Ionizing radiation, an important component of glioma therapy, is critically dependent on tumor oxygenation. However, gliomas are notable for areas of necrosis and hypoxia, which foster radioresistance. We hypothesized that pharmacologic manipulation of the typically dysfunctional tumor vasculature would improve intratumoral oxygenation and, thus, the antiglioma efficacy of ionizing radiation. Methods and Materials: Orthotopic U87 xenografts were treated with either continuous interferon-β (IFN-β) or bevacizumab, alone, or combined with cranial irradiation (RT). Tumor growth was assessed by quantitative bioluminescence imaging; the tumor vasculature using immunohistochemical staining, and tumor oxygenation using hypoxyprobe staining. Results: Both IFN-β and bevaziumab profoundly affected the tumor vasculature, albeit with different cellular phenotypes. IFN-β caused a doubling in the percentage of area of perivascular cell staining, and bevacizumab caused a rapid decrease in the percentage of area of endothelial cell staining. However, both agents increased intratumoral oxygenation, although with bevacizumab, the effect was transient, being lost by 5 days. Administration of IFN-β or bevacizumab before RT was significantly more effective than any of the three modalities as monotherapy or when RT was administered concomitantly with IFN-β or bevacizumab or 5 days after bevacizumab. Conclusion: Bevacizumab and continuous delivery of IFN-β each induced significant changes in glioma vascular physiology, improving intratumoral oxygenation and enhancing the antitumor activity of ionizing radiation. Additional investigation into the use and timing of these and other agents that modify the vascular phenotype, combined with RT, is warranted to optimize cytotoxic activity.

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

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

Inner Retinal Oxygen Extraction Fraction in Response to Light Flicker Stimulation in Humans

Science.gov (United States)

Felder, Anthony E.; Wanek, Justin; Blair, Norman P.; Shahidi, Mahnaz

2015-01-01

Purpose Light flicker has been shown to stimulate retinal neural activity, increase blood flow, and alter inner retinal oxygen metabolism (MO2) and delivery (DO2). The purpose of the study was to determine the change in MO2 relative to DO2 due to light flicker stimulation in humans, as assessed by the inner retinal oxygen extraction fraction (OEF). Methods An optical imaging system, based on a modified slit lamp biomicroscope, was developed for simultaneous measurements of retinal vascular diameter (D) and oxygen saturation (SO2). Retinal images were acquired in 20 healthy subjects before and during light flicker stimulation. Arterial and venous D (DA and DV) and SO2 (SO2A and SO2V) were quantified within a circumpapillary region. Oxygen extraction fraction was defined as the ratio of MO2 to DO2 and was calculated as (SO2A − SO2V)/SO2A. Reproducibility of measurements was assessed. Results Coefficients of variation and intraclass correlation coefficients of repeated measurements were <5% and ≥0.83, respectively. During light flicker stimulation, DA, DV , and SO2V significantly increased (P ≤ 0.004). Oxygen extraction fraction was 0.37 ± 0.08 before light flicker and significantly decreased to 0.31 ± 0.07 during light flicker (P = 0.001). Conclusions Oxygen extraction fraction before and during light flicker stimulation is reported in human subjects for the first time. Oxygen extraction fraction decreased during light flicker stimulation, indicating the change in DO2 exceeded that of MO2. This technology is potentially useful for the detection of changes in OEF response to light flicker in physiological and pathological retinal conditions. PMID:26469748

Survey of water quality in Moradbeik river basis on WQI index by GIS

Directory of Open Access Journals (Sweden)

Mohammad Taghi Samadi

2015-01-01

Full Text Available Background: Survey of pollution and evaluation of water quality in rivers with Oregon Water Quality Index (OWQI and GIS are effective tools for management of the impact of environmental water resources. The information in calculating the WQI of Moradbeikriver allowed us to take our tests results and make a scientific conclusion about the quality of water. GIS can be a powerful tool for developing solutions for water resources problems for assessing water quality, determining water availability, preventing flooding, understanding the natural environment, and managing water resources on a local or regional scale. Methods: The WQI of Moradbeikriver consists of nine tests: Fecal Coliform (FC, Biochemical Oxygen Demand (BOD5, Nitrates (NO3, Total Phosphate (PO4, pH, temperature, Dissolved Oxygen (DO, turbidity, and Total Solid (TS. Water quality of Moradbeikriver was investigated for 12 months. Concentrations of these nine variables were normalized on a scale from 0 to 100 and translated into statements of water quality (excellent, good, regular, fair, and poor. Also this data were analyzed with WQI index, and then river basis on water quality was zoning by GIS. Results: The average of WQI was 61.62, which corresponded to ‘‘medium’’ quality water at the sampling point 1 (best station and decreased to around 26.41 (bad quality at sampling point 6. The association between sampling points and water quality indexes was statistically significant (P<0.05. Conclusion: Based on physical, chemical and biological agent monitoring and also with control of water quality indexes of these points, we observed wastewater and other river pollutants.

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

Energy Technology Data Exchange (ETDEWEB)

Yarmonenko, S P; Ehpshtejn, I M [Akademiya Meditsinskikh Nauk SSSR, Moscow. Onkologicheskij Tsentr

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation.

Oxygen effect and intracellular oxygen content (adaptation hypothesis)

International Nuclear Information System (INIS)

Yarmonenko, S.P.; Ehpshtejn, I.M.

1977-01-01

Experimental data indicating that a radiomodifying action of hypoxia is dependent on the ''prehistory'' of the irradiated object are considered. This dependence manifests itself in a decreased protective action of acute hypoxia on the hypoxia-adapted objects. To explain this a hypothesis is proposed connecting a degree of cell radiosensitivity modification, determined by the oxygen effect, with the intracellular oxygen content. The latter, in accord with current ideas, is regulated by variations in the diffusion resistance to oxygen shown by the cytoplasmic membranes depending on the energy level of the cell and the degree of its oxygenation

INDEXING AND INDEX FUNDS

Directory of Open Access Journals (Sweden)

HAKAN SARITAŞ

2013-06-01

Full Text Available Proponents of the efficient market hypothesis believe that active portfolio management is largely wasted effort and unlikely to justify the expenses incurred. Therefore, they advocate a passive investment strategy that makes no attempt to outsmart the market. One common strategy for passive management is indexing where a fund is designed to replicate the performance of a broad-based index of stocks and bonds. Traditionally, indexing was used by institutional investors, but today, the use of index funds proliferated among individual investors. Over the years, both international and domestic index funds have disproportionately outperformed the market more than the actively managed funds have.

Step Test: a method for evaluating maximum oxygen consumption to determine the ability kind of work among students of medical emergencies.

Science.gov (United States)

Heydari, Payam; Varmazyar, Sakineh; Nikpey, Ahmad; Variani, Ali Safari; Jafarvand, Mojtaba

2017-03-01

Maximum oxygen consumption shows the maximum oxygen rate of muscle oxygenation that is acceptable in many cases, to measure the fitness between person and the desired job. Given that medical emergencies are important, and difficult jobs in emergency situations require people with high physical ability and readiness for the job, the aim of this study was to evaluate the maximum oxygen consumption, to determine the ability of work type among students of medical emergencies in Qazvin in 2016. This study was a descriptive - analytical, and in cross-sectional type conducted among 36 volunteer students of medical emergencies in Qazvin in 2016. After necessary coordination for the implementation of the study, participants completed health questionnaires and demographic characteristics and then the participants were evaluated with step tests of American College of Sport Medicine (ACSM). Data analysis was done by SPSS version 18 and U-Mann-Whitney tests, Kruskal-Wallis and Pearson correlation coefficient. Average of maximum oxygen consumption of the participants was estimated 3.15±0.50 liters per minute. 91.7% of medical emergencies students were selected as appropriate in terms of maximum oxygen consumption and thus had the ability to do heavy and too heavy work. Average of maximum oxygen consumption evaluated by the U-Mann-Whitney test and Kruskal-Wallis, had significant relationship with age (p<0.05) and weight groups (p<0.001). There was a significant positive correlation between maximum oxygen consumption with weight and body mass index (p<0.001). The results of this study showed that demographic variables of weight and body mass index are the factors influencing the determination of maximum oxygen consumption, as most of the students had the ability to do heavy, and too heavy work. Therefore, people with ability to do average work are not suitable for medical emergency tasks.

Biceps brachii muscle oxygenation in electrical muscle stimulation.

Science.gov (United States)

Muthalib, Makii; Jubeau, Marc; Millet, Guillaume Y; Maffiuletti, Nicola A; Ferrari, Marco; Nosaka, Kazunori

2010-09-01

The purpose of this study was to compare between electrical muscle stimulation (EMS) and maximal voluntary (VOL) isometric contractions of the elbow flexors for changes in biceps brachii muscle oxygenation (tissue oxygenation index, TOI) and haemodynamics (total haemoglobin volume, tHb = oxygenated-Hb + deoxygenated-Hb) determined by near-infrared spectroscopy (NIRS). The biceps brachii muscle of 10 healthy men (23-39 years) was electrically stimulated at high frequency (75 Hz) via surface electrodes to evoke 50 intermittent (4-s contraction, 15-s relaxation) isometric contractions at maximum tolerated current level (EMS session). The contralateral arm performed 50 intermittent (4-s contraction, 15-s relaxation) maximal voluntary isometric contractions (VOL session) in a counterbalanced order separated by 2-3 weeks. Results indicated that although the torque produced during EMS was approximately 50% of VOL (P<0.05), there was no significant difference in the changes in TOI amplitude or TOI slope between EMS and VOL over the 50 contractions. However, the TOI amplitude divided by peak torque was approximately 50% lower for EMS than VOL (P<0.05), which indicates EMS was less efficient than VOL. This seems likely because of the difference in the muscles involved in the force production between conditions. Mean decrease in tHb amplitude during the contraction phases was significantly (P<0.05) greater for EMS than VOL from the 10th contraction onwards, suggesting that the muscle blood volume was lower in EMS than VOL. It is concluded that local oxygen demand of the biceps brachii sampled by NIRS is similar between VOL and EMS.

Nanodiamonds as novel nanomaterials for biomedical applications: drug delivery and imaging systems.

Science.gov (United States)

Kaur, Randeep; Badea, Ildiko

2013-01-01

Detonation nanodiamonds (NDs) are emerging as delivery vehicles for small chemical drugs and macromolecular biotechnology products due to their primary particle size of 4 to 5 nm, stable inert core, reactive surface, and ability to form hydrogels. Nanoprobe technology capitalizes on the intrinsic fluorescence, high refractive index, and unique Raman signal of the NDs, rendering them attractive for in vitro and in vivo imaging applications. This review provides a brief introduction of the various types of NDs and describes the development of procedures that have led to stable single-digit-sized ND dispersions, a crucial feature for drug delivery systems and nanoprobes. Various approaches used for functionalizing the surface of NDs are highlighted, along with a discussion of their biocompatibility status. The utilization of NDs to provide sustained release and improve the dispersion of hydrophobic molecules, of which chemotherapeutic drugs are the most investigated, is described. The prospects of improving the intracellular delivery of nucleic acids by using NDs as a platform are exemplified. The photoluminescent and optical scattering properties of NDs, together with their applications in cellular labeling, are also reviewed. Considering the progress that has been made in understanding the properties of NDs, they can be envisioned as highly efficient drug delivery and imaging biomaterials for use in animals and humans.

Theory and development of fluorescence-based optochemical oxygen sensors: oxygen optodes.

Science.gov (United States)

Opitz, N; Lübbers, D W

1987-01-01

As the preceding considerations concerning the physical and technical features of oxygen optodes have demonstrated, fluorescence-based optochemical oxygen sensors possess certain advantages and peculiarities compared to conventionally applied electrochemical sensors such as polarographic oxygen electrodes. First, in contrast to oxygen electrodes, oxygen measurements with oxygen optodes do not suffer from distortions caused by the reference electrodes. In addition, because of the polarographic process, platinum electrodes continuously consume oxygen, which falsifies the results, especially when small sample volumes or long-term measurements, or both, are involved, whereas the sensor layer of oxygen optodes must only be equilibrated. Moreover, the surface of the platinum wire has to be catalytically clean in order to obtain a plateau of the polarogram and, consequently, to achieve a low rest current at zero PO2. Unfortunately, the demand for catalytically clean platinum surfaces turns out to be rather critical, since surface contamination occurs even with membranized electrodes, resulting in the well-known phenomenon of "electrode poisoning." The question of the specificity of oxygen electrodes also must be considered. In this context, CO2 and halothane may interfere with oxygen measurements, whereas fluorescence quenching is unaffected by CO2 and halothane affects the measurements only slightly, depending on the special indicator used. Furthermore, because of the flow dependence, oxygen measurements with the oxygen electrode show a distinct "stirring effect" caused by the turbulence in front of the electrode, which disturbs the diffusion field. Because of the completely different physical principle of fluorescence optical sensors, such influences are not observed with oxygen optodes. In addition, isolation and shielding of electrical circuits found in electrodes are not necessary for optodes. Furthermore, the sensitivity of oxygen optodes can be tuned to the desired

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 ...

The oxygen-conserving potential of the diving response: A kinetic-based analysis.

Science.gov (United States)

Costalat, Guillaume; Coquart, Jeremy; Castres, Ingrid; Joulia, Fabrice; Sirost, Olivier; Clua, Eric; Lemaître, Frédéric

2017-04-01

We investigated the oxygen-conserving potential of the human diving response by comparing trained breath-hold divers (BHDs) to non-divers (NDs) during simulated dynamic breath-holding (BH). Changes in haemodynamics [heart rate (HR), stroke volume (SV), cardiac output (CO)] and peripheral muscle oxygenation [oxyhaemoglobin ([HbO 2 ]), deoxyhaemoglobin ([HHb]), total haemoglobin ([tHb]), tissue saturation index (TSI)] and peripheral oxygen saturation (SpO 2 ) were continuously recorded during simulated dynamic BH. BHDs showed a breaking point in HR kinetics at mid-BH immediately preceding a more pronounced drop in HR (-0.86 bpm.% -1 ) while HR kinetics in NDs steadily decreased throughout BH (-0.47 bpm.% -1 ). By contrast, SV remained unchanged during BH in both groups (all P > 0.05). Near-infrared spectroscopy (NIRS) results (mean ± SD) expressed as percentage changes from the initial values showed a lower [HHb] increase for BHDs than for NDs at the cessation of BH (+24.0 ± 10.1 vs. +39.2 ± 9.6%, respectively; P kinetic-based approach we used provides further credence to the concept of an "oxygen-conserving breaking point" in the human diving response.

Retinal Vessel Oxygen Saturation during 100% Oxygen Breathing in Healthy Individuals.

Directory of Open Access Journals (Sweden)

Olof Birna Olafsdottir

Full Text Available To detect how systemic hyperoxia affects oxygen saturation in retinal arterioles and venules in healthy individuals.Retinal vessel oxygen saturation was measured in 30 healthy individuals with a spectrophotometric retinal oximeter (Oxymap T1. Oximetry was performed during breathing of room air, 100% oxygen (10 minutes, 6L/min and then again room air (10 minutes recovery.Mean oxygen saturation rises modestly in retinal arterioles during 100% oxygen breathing (94.5%±3.8 vs. 92.0%±3.7% at baseline, p<0.0001 and dramatically in retinal venules (76.2%±8.0% vs. 51.3%±5.6%, p<0.0001. The arteriovenous difference decreased during 100% oxygen breathing (18.3%±9.0% vs. 40.7%±5.7%, p<0.0001. The mean diameter of arterioles decreased during 100% oxygen breathing compared to baseline (9.7±1.4 pixels vs. 10.3±1.3 pixels, p<0.0001 and the same applies to the mean venular diameter (11.4±1.2 pixels vs. 13.3±1.5 pixels, p<0.0001.Breathing 100% oxygen increases oxygen saturation in retinal arterioles and more so in venules and constricts them compared to baseline levels. The dramatic increase in oxygen saturation in venules reflects oxygen flow from the choroid and the unusual vascular anatomy and oxygen physiology of the eye.

Comparison between model-predicted tumor oxygenation dynamics and vascular-/flow-related Doppler indices.

Science.gov (United States)

Belfatto, Antonella; Vidal Urbinati, Ailyn M; Ciardo, Delia; Franchi, Dorella; Cattani, Federica; Lazzari, Roberta; Jereczek-Fossa, Barbara A; Orecchia, Roberto; Baroni, Guido; Cerveri, Pietro

2017-05-01

two presented poor correlations. The latter patients were the ones featuring the smallest tumor reduction throughout the treatment, typical of hypoxic conditions. Moreover, the average oxygenation value predicted by the model was close to the average vascularization-flow index (average difference: 7%). The results suggest that the modeled relation between tumor evolution and oxygen dynamics was reasonable enough to provide realistic oxygenation curves in five cases (correlation greater than 50%) out of seven. In case of nonresponsive tumors, the model failed in predicting the oxygenation trend while succeeded in reproducing the average oxygenation value according to the mean vascularization-flow index. Despite the need for deeper investigations, the outcomes of the present work support the hypothesis that a simple macroscale model of tumor response to radiotherapy is able to predict the tumor oxygenation. The possibility of an objective and quantitative validation on imaging data discloses the possibility to translate them as decision support tools in clinical practice and to move a step forward in the treatment personalization. © 2017 American Association of Physicists in Medicine.

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.

Childhood overweight after establishment of the gut microbiota: the role of delivery mode, pre-pregnancy weight and early administration of antibiotics

DEFF Research Database (Denmark)

Adeltoft, Teresa Ajslev; Andersen, C S; Gamborg, M

2011-01-01

Objective: To investigate whether delivery mode (vaginal versus by caesarean section), maternal pre-pregnancy body mass index (BMI) and early exposure to antibiotics (..., with information on maternal pre-pregnancy BMI, delivery mode and antibiotic administration in infancy, were assessed. Logistic regression analyses were performed with childhood height and weight at the 7-year follow-up as outcome measures. Results: Delivery mode was not significantly associated with childhood.......54, 95% CI: 0.30–0.98). The same tendency was observed among children of obese mothers (OR: 0.85, 95% CI: 0.41–1.76). Conclusion: The present cohort study revealed that a combination of early exposures, including delivery mode, maternal pre-pregnancy BMI and antibiotics in infancy, influences the risk...

Meal frequency patterns and glycemic properties of maternal diet in relation to preterm delivery: Results from a large prospective cohort study.

Science.gov (United States)

Englund-Ögge, Linda; Birgisdottir, Bryndis Eva; Sengpiel, Verena; Brantsæter, Anne Lise; Haugen, Margareta; Myhre, Ronny; Meltzer, Helle Margrete; Jacobsson, Bo

2017-01-01

Dietary habits are linked to high maternal glucose levels, associated with preterm delivery. The aim of this study was to examine the associations between meal frequency and glycemic properties of maternal diet in relation to preterm delivery. This prospective cohort study included 66,000 women from the Norwegian Mother and Child Cohort Study (MoBa). Meal frequency and food intake data were obtained from a validated food frequency questionnaire during mid-pregnancy. Principal component factor analysis was used with a data-driven approach, and three meal frequency patterns were identified: "snack meal", "main meal", and "evening meal". Pattern scores were ranked in quartiles. Glycemic index and glycemic load were estimated from table values. Intakes of carbohydrates, added sugar, and fiber were reported in grams per day and divided into quartiles. Gestational age was obtained from the Medical Birth Registry of Norway. Preterm delivery was defined as birth at meal" pattern was associated with a reduced risk of preterm delivery, with hazard ratios (HRs) of 0.89 (95% confidence interval (CI): 0.80, 0.98) and 0.90 (95% CI: 0.81, 0.99) for the third and fourth quartiles, respectively, and p for trend of 0.028. This was mainly attributed to the group of women with BMI ≥25 kg/m2, with HRs of 0.87 (95% CI: 0.79, 0.96) and 0.89 (95% CI: 0.80, 0.98) for the third and fourth quartiles, respectively, and p for trend of 0.010. There was no association between glycemic index, glycemic load, carbohydrates, added sugar, fiber, or the remaining meal frequency patterns and preterm delivery. Regular consumption of main meals (breakfast, lunch, dinner) was associated with a lower risk of preterm delivery. Diet should be further studied as potential contributing factors for preterm delivery.

eDelivery

Data.gov (United States)

US Agency for International Development — eDelivery provides the electronic packaging and delivery of closed and complete OPM investigation files to government agencies, including USAID, in a secure manner....

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

Science.gov (United States)

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

2016-04-01

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

Reactive oxygen species explicit dosimetry (ROSED) of a type 1 photosensitizer

Science.gov (United States)

Ong, Yi Hong; Kim, Michele M.; Huang, Zheng; Zhu, Timothy C.

2018-02-01

Type I photodynamic therapy (PDT) is based on the use of photochemical reactions mediated through an interaction between a tumor-selective photosensitizer, photoexcitation with a specific wavelength of light, and production of reactive oxygen species (ROS). The goal of this study is to develop a model to calculate reactive oxygen species concentration ([ROS]rx) after Tookad®-mediated vascular PDT. Mice with radiation-induced fibrosarcoma (RIF) tumors were treated with different light fluence and fluence rate conditions. Explicit measurements of photosensitizer drug concentration were made via diffuse reflective absorption spectrum using a contact probe before and after PDT. Blood flow and tissue oxygen concentration over time were measured during PDT as a mean to validate the photochemical parameters for the ROSED calculation. Cure index was computed from the rate of tumor regrowth after treatment and was compared against three calculated dose metrics: total light fluence, PDT dose, reacted [ROS]rx. The tumor growth study demonstrates that [ROS]rx serves as a better dosimetric quantity for predicting treatment outcome, as a clinically relevant tumor growth endpoint.

Diffusive flux in a model of stochastically gated oxygen transport in insect respiration

Energy Technology Data Exchange (ETDEWEB)

Berezhkovskii, Alexander M. [Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892 (United States); Shvartsman, Stanislav Y. [Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544 (United States)

2016-05-28

Oxygen delivery to insect tissues is controlled by transport through a branched tubular network that is connected to the atmosphere by valve-like gates, known as spiracles. In certain physiological regimes, the spiracles appear to be randomly switching between open and closed states. Quantitative analysis of this regime leads a reaction-diffusion problem with stochastically switching boundary condition. We derive an expression for the diffusive flux at long times in this problem. Our approach starts with the derivation of the passage probability for a single particle that diffuses between a stochastically gated boundary, which models the opening and closing spiracle, and the perfectly absorbing boundary, which models oxygen absorption by the tissue. This passage probability is then used to derive an expression giving the diffusive flux as a function of the geometric parameters of the tube and characteristic time scales of diffusion and gate dynamics.

In vitro autoradiographic studies for determination of mitotic index and labelling index in biopsies of the human oral mucosa

International Nuclear Information System (INIS)

Etzbach, T.

1980-01-01

In order to find the most favourable method of incubation for in-vitro autoradiographies of biopsies of human oral mucosa, tissue biopsies were taken from oral mucosa transplants of 10 patients (7 females, 3 males) and either fixed or incubated at once. The author then investigated the mitotic index of the non-incubated tissue specimens, the mitotic index of the tissue specimens incubated in atmospheric conditions (A), and the mitotic index of the tissue specimens incubated under pressure (B). Simultaneously, autoradiographs of the incubated tissue specimens were prepared in order to determine their labelling indices. The mitotic indices of the non-incubated tissue specimen were found to differ significantly from those of the A-incubated tissue specimens. A similar difference was found between the mitotic indices of the A- and B-incubated tissue biopsies. Further, the labelling indices of A autoradiographs differed significantly from the labelling indices of B autoradiographs. The findings suggest that incubation with an excess oxygen pressure of 2 bar is the method of choice for in-vitro studies of human oral mucosa as the cells retain their specific activity and cell processes will continue unhindered. Further, the findings can be transferred to in-vivo conditions with a reasonable error rate. (orig./MG) [de

UAV Delivery Monitoring System

Directory of Open Access Journals (Sweden)

San Khin Thida

2018-01-01

Full Text Available UAV-based delivery systems are increasingly being used in the logistics field, particularly to achieve faster last-mile delivery. This study develops a UAV delivery system that manages delivery order assignments, autonomous flight operation, real time control for UAV flights, and delivery status tracking. To manage the delivery item assignments, we apply the concurrent scheduler approach with a genetic algorithm. The present paper describes real time flight data based on a micro air vehicle communication protocol (MAVLink. It also presents the detailed hardware components used for the field tests. Finally, we provide UAV component analysis to choose the suitable components for delivery in terms of battery capacity, flight time, payload weight and motor thrust ratio.

Spontaneous vaginal delivery in the birth-chair versus in the conventional dorsal position: a matched controlled comparison.

Science.gov (United States)

Scholz, H S; Benedicic, C; Arikan, M G; Haas, J; Petru, E

2001-09-17

The aim of the study was to assess the effect of a birth-chair on obstetric outcome. We reviewed the hospital records of 220 consecutive pregnant women who gave birth on a birth-chair at our institution. The control group consisted of 440 pregnant women who preceded and followed the index cases and who had spontaneous vaginal deliveries in the conventional dorsal supine position. The controls were matched for parity and for the attending mid-wife. Patients who delivered in the birth-chair had significantly lower rates of episiotomy and manual separation of the placenta. The umbilical blood cord pH was significantly higher in neonates of the birth-chair group. The duration of labour, rate of perineal and vaginal injury, Apgar scores and rate of admission to a neonatal intermediate care unit were not influenced by the mode of delivery. Our data support previous studies that a birth-chair delivery may be a safe alternative to conventional delivery in the supine position.

OPTIMIZATION OF THE CRITERION FOR ESTIMATING THE TECHNOLOGY EFFICIENCY OF PACKING-CASE-PIECE LOADS DELIVERY

OpenAIRE

O. Severyn; O. Shulika

2017-01-01

The results of optimization of gravimetric coefficients for indexes included in the integral criterion of estimation of the efficiency of transport-technological charts of cargo delivery are resulted. The values of gravimetric coefficients are determined on the basis of two methods of experimental researches: questioning of respondents among the specialists of motor transport production and imitation design.

Central Hemodynamics and Oxygen Transport in Various Activation of Patients Operated On Under Extracorporeal Circulation

Directory of Open Access Journals (Sweden)

Ye. V. Dzybinskaya

2009-01-01

Full Text Available Objective: to study central hemodynamics, the determinants of myocardial oxygen balance, and the parameters of oxygen transport in various activation of patients after surgery under extracorporeal circulation. Subjects and methods. Thirty-four patients aged 57.8±2.5 years who had coronary heart disease were divided into 2 groups: 1 those with late activation (artificial ventilation time 157±9 min and 2 those with immediate activation (artificial ventilation time 33±6 min. Group 2 patients were, if required, given fentanyl, midazolam, or myorelaxants. Results. During activation, there were no intergroup differences in the mean levels of the major parameters of cardiac pump function, in the determinants of coronary blood flow (coronary perfusion gradients and myocardial oxygen demand (the product of heart rate by systolic blood pressure, and in the parameters of oxygen transport, including arterial lactatemia. After tracheal extubation, the left ventricular pump coefficient was increased considerably (up to 3.8±0.2 and 4.4±0.2 gm/mm Hg/m2 in Groups 1 and 2, respectively; p<0.05 with minimum inotropic support (dopamine and/or dobutamine being used at 2.7±0.3 and 2.4±0.3 mg/kg/min, respectively. In both groups, there were no close correlations between the indices of oxygen delivery and consumption at all stages of the study, which was indicative of no transport-dependent oxygen uptake. Conclusion. When the early activation protocol was followed up, the maximum acceleration of early activation, including that using specific antagonists of anesthetics, has no negative impact on central hemodynamics, the determinants of myocardial oxygen balance and transport in patients operated on under extracorporeal circulation. Key words: early activation, surgery under extracorporeal circulation, tracheal extubation in the operating-room, central hemodynamics, oxygen transport.

Maternal prepregnancy body mass index and gestational weight gain on pregnancy outcomes.

Directory of Open Access Journals (Sweden)

Nan Li

Full Text Available The aim of the present study was to evaluate the single and joint associations of maternal prepregnancy body mass index (BMI and gestational weight gain (GWG with pregnancy outcomes in Tianjin, China.Between June 2009 and May 2011, health care records of 33,973 pregnant women were collected and their children were measured for birth weight and birth length. The independent and joint associations of prepregnancy BMI and GWG based on the Institute of Medicine (IOM guidelines with the risks of pregnancy and neonatal outcomes were examined by using Logistic Regression.After adjustment for all confounding factors, maternal prepregnancy BMI was positively associated with risks of gestational diabetes mellitus (GDM, pregnancy-induced hypertension, caesarean delivery, preterm delivery, large-for-gestational age infant (LGA, and macrosomia, and inversely associated with risks of small-for-gestational age infant (SGA and low birth weight. Maternal excessive GWG was associated with increased risks of pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia, and decreased risks of preterm delivery, SGA, and low birth weight. Maternal inadequate GWG was associated with increased risks of preterm delivery and SGA, and decreased risks of LGA and macrosomia, compared with maternal adequate GWG. Women with both prepregnancy obesity and excessive GWG had 2.2-5.9 folds higher risks of GDM, pregnancy-induced hypertension, caesarean delivery, LGA, and macrosomia compared with women with normal prepregnancy BMI and adequate GWG.Maternal prepregnancy obesity and excessive GWG were associated with greater risks of pregnancy-induced hypertension, caesarean delivery, and greater infant size at birth. Health care providers should inform women to start the pregnancy with a BMI in the normal weight category and limit their GWG to the range specified for their prepregnancy BMI.

Simultaneously Occurring Elevated Metabolic States Expose Constraints in Maximal Levels of Oxygen Consumption in the Oviparous Snake Lamprophis fuliginosus.

Science.gov (United States)

Jackson, Alexander Garrett Schavran; Leu, Szu-Yun; Hicks, James W

African house snakes (Lamprophis fuliginosus) were used to compare the metabolic increments associated with reproduction, digestion, and activity both individually and when combined simultaneously. Rates of oxygen consumption ([Formula: see text]) and carbon dioxide production ([Formula: see text]) were measured in adult female (nonreproductive and reproductive) and adult male snakes during rest, digestion, activity while fasting, and postprandial activity. We also compared the endurance time (i.e., time to exhaustion) during activity while fasting and postprandial activity in males and females. For nonreproductive females and males, our results indicate that the metabolic increments of digestion (∼3-6-fold) and activity while fasting (∼6-10-fold) did not interact in an additive fashion; instead, the aerobic scope associated with postprandial activity was 40%-50% lower, and animals reached exhaustion up to 11 min sooner. During reproduction, there was no change in digestive [Formula: see text], but aerobic scope for activity while fasting was 30% lower than nonreproductive values. The prioritization pattern of oxygen delivery exhibited by L. fuliginosus during postprandial activity (in both males and females) and for activity while fasting (in reproductive females) was more constrained than predicted (i.e., instead of unchanged [Formula: see text], peak values were 30%-40% lower). Overall, our results indicate that L. fuliginosus's cardiopulmonary system's capacity for oxygen delivery was not sufficient to maintain the metabolic increments associated with reproduction, digestion, and activity simultaneously without limiting aerobic scope and/or activity performance.

Outcome of deliveries in healthy but obese women: obesity and delivery outcome

Directory of Open Access Journals (Sweden)

Kaplan-Sturk Rebecka

2013-02-01

Full Text Available Abstract Background Obesity among fertile women is a global problem. 25% of pregnant Swedish women are overweight at admission to the antenatal clinic and 12% of them are considered as obese. Previous studies have shown an increased risk of delivery complications with an elevated maternal BMI. The aim of this study was to evaluate delivery outcomes in relation to maternal BMI on admission to the antenatal clinic. A healthy group of 787 women with full-term pregnancies and spontaneous onset of labor were included in the study. Delivery outcome was assessed in relation to maternal BMI when attending the antenatal clinic. Results The results indicated that in deliveries where the maternal BMI was >30 a high frequency of abnormal CTG trace during the last 30 minutes of labor was shown. A blood sample for evaluation of risk of fetal hypoxia was performed in only eight percent of these deliveries. A spontaneous vaginal delivery without intervention was noted in 85.7%, and 12% of neonates were delivered with an adverse fetal outcome compared to 2.8% in the group with a maternal BMI Conclusion These results indicate an increased risk at delivery for healthy, but obese women in labor. Furthermore, the delivery management may not always be optimal in these deliveries.

Calculations of oxide formation on low-index Cu surfaces

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Lian, Xin; Liu, Renlong, E-mail: lrl@cqu.edu.cn, E-mail: henkelman@utexas.edu [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Xiao, Penghao; Yang, Sheng-Che; Henkelman, Graeme, E-mail: lrl@cqu.edu.cn, E-mail: henkelman@utexas.edu [Department of Chemistry and the Institute for Computational and Engineering Sciences, University of Texas at Austin, Austin, Texas 78712-0165 (United States)

2016-07-28

Density-functional theory is used to evaluate the mechanism of copper surface oxidation. Reaction pathways of O{sub 2} dissociation on the surface and oxidation of the sub-surface are found on the Cu(100), Cu(110), and Cu(111) facets. At low oxygen coverage, all three surfaces dissociate O{sub 2} spontaneously. As oxygen accumulates on the surfaces, O{sub 2} dissociation becomes more difficult. A bottleneck to further oxidation occurs when the surfaces are saturated with oxygen. The barriers for O{sub 2} dissociation on the O-saturated Cu(100)-c(2×2)-0.5 monolayer (ML) and Cu(100) missing-row structures are 0.97 eV and 0.75 eV, respectively; significantly lower than those have been reported previously. Oxidation of Cu(110)-c(6×2), the most stable (110) surface oxide, has a barrier of 0.72 eV. As the reconstructions grow from step edges, clean Cu(110) surfaces can dissociatively adsorb oxygen until the surface Cu atoms are saturated. After slight rearrangements, these surface areas form a “1 ML” oxide structure which has not been reported in the literature. The barrier for further oxidation of this “1 ML” phase is only 0.31 eV. Finally the oxidized Cu(111) surface has a relatively low reaction energy barrier for O{sub 2} dissociation, even at high oxygen coverage, and allows for facile oxidation of the subsurface by fast O diffusion through the surface oxide. The kinetic mechanisms found provide a qualitative explanation of the observed oxidation of the low-index Cu surfaces.

Feasibility study on the verification of actual beam delivery in a treatment room using EPID transit dosimetry

International Nuclear Information System (INIS)

Baek, Tae Seong; Chung, Eun Ji; Son, Jaeman; Yoon, Myonggeun

2014-01-01

The aim of this study is to evaluate the ability of transit dosimetry using commercial treatment planning system (TPS) and an electronic portal imaging device (EPID) with simple calibration method to verify the beam delivery based on detection of large errors in treatment room. Twenty four fields of intensity modulated radiotherapy (IMRT) plans were selected from four lung cancer patients and used in the irradiation of an anthropomorphic phantom. The proposed method was evaluated by comparing the calculated dose map from TPS and EPID measurement on the same plane using a gamma index method with a 3% dose and 3 mm distance-to-dose agreement tolerance limit. In a simulation using a homogeneous plastic water phantom, performed to verify the effectiveness of the proposed method, the average passing rate of the transit dose based on gamma index was high enough, averaging 94.2% when there was no error during beam delivery. The passing rate of the transit dose for 24 IMRT fields was lower with the anthropomorphic phantom, averaging 86.8% ± 3.8%, a reduction partially due to the inaccuracy of TPS calculations for inhomogeneity. Compared with the TPS, the absolute value of the transit dose at the beam center differed by −0.38% ± 2.1%. The simulation study indicated that the passing rate of the gamma index was significantly reduced, to less than 40%, when a wrong field was erroneously irradiated to patient in the treatment room. This feasibility study suggested that transit dosimetry based on the calculation with commercial TPS and EPID measurement with simple calibration can provide information about large errors for treatment beam delivery

Timing of delivery after external cephalic version and the risk for cesarean delivery.

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Kabiri, Doron; Elram, Tamar; Aboo-Dia, Mushira; Elami-Suzin, Matan; Elchalal, Uriel; Ezra, Yossef

2011-08-01

To estimate the association between time of delivery after external cephalic version at term and the risk for cesarean delivery. This retrospective cohort study included all successful external cephalic versions performed in a tertiary center between January 1997 and January 2010. Stepwise logistic regression was used to calculate the odds ratio (OR) for cesarean delivery. We included 483 external cephalic versions in this study, representing 53.1% of all external cephalic version attempts. The incidence of cesarean delivery for 139 women (29%) who gave birth less than 96 hours from external cephalic version was 16.5%; for 344 women (71%) who gave birth greater than 96 hours from external cephalic version, the incidence of cesarean delivery was 7.8% (P = .004). The adjusted OR for cesarean delivery was 2.541 (95% confidence interval 1.36-4.72). When stratified by parity, the risk for cesarean delivery when delivery occurred less than 96 hours after external cephalic version was 2.97 and 2.28 for nulliparous and multiparous women, respectively. Delivery at less than 96 hours after successful external cephalic version was associated with an increased risk for cesarean delivery. III.

Hemodynamic comparison of mild and severe preeclampsia: concept of stroke systemic vascular resistance index.

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Scardo, J; Kiser, R; Dillon, A; Brost, B; Newman, R

1996-01-01

Our purpose was to compare baseline hemodynamic parameters of mild and severe preeclampsia. Patients admitted to the Medical University Labor and Delivery Unit with the diagnosis of preeclampsia who had not received prior antihypertensive or magnesium sulfate therapy were recruited for noninvasive hemodynamic monitoring with thoracic electrical bioimpedance. After stabilization in the lateral recumbent position, hemodynamic monitoring was begun. Baseline hemodynamic parameters, mean arterial pressure (MAP), heart rate (HR), systemic vascular resistance index (SVRI), cardiac index (CI), and stroke index (SI) were recorded. Stroke systemic vascular resistance index (SSVRI), the resistance imposed by vasculature on each beat of the heart, was calculated for each patient by multiplying SVRI by HR. For statistical analysis, unpaired Student's t-tests (two-tailed) were utilized (P preclampsia appears to be a more intensely vasoconstricted state than mild preeclampsia. Although CI is inversely proportional to SVRI, increased HR in severe preeclampsia prevents this expected decrease in cardiac output.

Oxygen delivery and the restoration of the muscle energetic balance following exercise: implications for delayed muscle recovery in patients with COPD.

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Layec, Gwenael; Hart, Corey R; Trinity, Joel D; Kwon, Oh-Sung; Rossman, Matthew J; Broxterman, Ryan M; Le Fur, Yann; Jeong, Eun-Kee; Richardson, Russell S

2017-07-01

Patients with chronic obstructive pulmonary disease (COPD) experience a delayed recovery from skeletal muscle fatigue following exhaustive exercise that likely contributes to their progressive loss of mobility. As this phenomenon is not well understood, this study sought to examine postexercise peripheral oxygen (O 2 ) transport and muscle metabolism dynamics in patients with COPD, two important determinants of muscle recovery. Twenty-four subjects, 12 nonhypoxemic patients with COPD and 12 healthy subjects with a sedentary lifestyle, performed dynamic plantar flexion exercise at 40% of the maximal work rate (WR max ) with phosphorus magnetic resonance spectroscopy ( 31 P-MRS), near-infrared spectroscopy (NIRS), and vascular Doppler ultrasound assessments. The mean response time of limb blood flow at the offset of exercise was significantly prolonged in patients with COPD (controls: 56 ± 27 s; COPD: 120 ± 87 s; P 0.05). The initial postexercise convective O 2 delivery (controls: 0.15 ± 0.06 l/min; COPD: 0.15 ± 0.06 l/min) and the corresponding oxidative adenosine triphosphate (ATP) demand (controls: 14 ± 6 mM/min; COPD: 14 ± 6 mM/min) in the calf were not significantly different between controls and patients with COPD ( P > 0.05). The phosphocreatine resynthesis time constant (controls: 46 ± 20 s; COPD: 49 ± 21 s), peak mitochondrial phosphorylation rate, and initial proton efflux were also not significantly different between groups ( P > 0.05). Therefore, despite perturbed peripheral hemodynamics, intracellular O 2 availability, proton efflux, and aerobic metabolism recovery in the skeletal muscle of nonhypoxemic patients with COPD are preserved following plantar flexion exercise and thus are unlikely to contribute to the delayed recovery from exercise in this population.

A Quantitative Study of Oxygen as a Metabolic Regulator

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Radhakrishnan, Krishnan; LaManna, Joseph C.; Cabrera, Marco E.

1999-01-01

An acute reduction in oxygen (O2) delivery to a tissue is generally associated with a decrease in phosphocreatine, increases in ADP, NADH/NAD, and inorganic phosphate, increased rates of glycolysis and lactate production, and reduced rates of pyruvate and fatty acid oxidation. However, given the complexity of the human bioenergetic system and its components, it is difficult to determine quantitatively how cellular metabolic processes interact to maintain ATP homeostasis during stress (e.g., hypoxia, ischemia, and exercise). Of special interest is the determination of mechanisms relating tissue oxygenation to observed metabolic responses at the tissue, organ, and whole body levels and the quantification of how changes in tissue O2 availability affect the pathways of ATP synthesis and the metabolites that control these pathways. In this study, we extend a previously developed mathematical model of human bioenergetics to provide a physicochemical framework that permits quantitative understanding of O2 as a metabolic regulator. Specifically, the enhancement permits studying the effects of variations in tissue oxygenation and in parameters controlling the rate of cellular respiration on glycolysis, lactate production, and pyruvate oxidation. The whole body is described as a bioenergetic system consisting of metabolically distinct tissue/organ subsystems that exchange materials with the blood. In order to study the dynamic response of each subsystem to stimuli, we solve the ordinary differential equations describing the temporal evolution of metabolite levels, given the initial concentrations. The solver used in the present study is the packaged code LSODE, as implemented in the NASA Lewis kinetics and sensitivity analysis code, LSENS. A major advantage of LSENS is the efficient procedures supporting systematic sensitivity analysis, which provides the basic methods for studying parameter sensitivities (i.e., changes in model behavior due to parameter variation

Evaluation of critical formulation parameters in design and differentiation of self-microemulsifying drug delivery systems (SMEDDSs) for oral delivery of aciclovir.

Science.gov (United States)

Janković, Jovana; Djekic, Ljiljana; Dobričić, Vladimir; Primorac, Marija

2016-01-30

The study investigated the influence of formulation parameters for design of self-microemulsifying drug delivery systems (SMEDDSs) comprising oil (medium chain triglycerides) (10%), surfactant (Labrasol(®), polysorbate 20, or Kolliphor(®) RH40), cosurfactant (Plurol(®) Oleique CC 497) (q.s. ad 100%), and cosolvent (glycerol or macrogol 400) (20% or 30%), and evaluate their potential as carriers for oral delivery of a poorly permeable antivirotic aciclovir (acyclovir). The drug loading capacity of the prepared formulations ranged from 0.18-31.66 mg/ml. Among a total of 60 formulations, three formulations meet the limits for average droplet size (Z-ave) and polydispersity index (PdI) that have been set for SMEDDSs (Z-ave≤100nm, PdI<0.250) upon spontaneous dispersion in 0.1M HCl and phosphate buffer pH 7.2. SMEDDSs with the highest aciclovir loading capacity (24.06 mg/ml and 21.12 mg/ml) provided the in vitro drug release rates of 0.325 mg cm(-2)min(-1) and 0.323 mg cm(-2)min(-1), respectively, and significantly enhanced drug permeability in the parallel artificial membrane permeability assay (PAMPA), in comparison with the pure drug substance. The results revealed that development of SMEDDSs with enhanced drug loading capacity and oral delivery potential, required optimization of hydrophilic ingredients, in terms of size of hydrophilic moiety of the surfactant, surfactant-to-cosurfactant mass ratio (Km), and log P of the cosolvent. Copyright © 2015 Elsevier B.V. All rights reserved.

Providing Oxygen for the Crew of a Lunar Outpost

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Ewert, Michael K.; Jeng, Frank; Conger, Bruce; Anderson, Molly S.

2009-01-01

Oxygen (O2) is obviously essential for human space missions, but it is important to examine all the different ways it will be used and the potential sources that it may come from. This effort will lead to storage and delivery requirements and help to determine the optimum architecture from an overall systems engineering point of view. Accounting for all the oxygen in a Lunar Outpost mission includes meeting the metabolic needs of the crew while in the surface Habitat, leakage through the Habitat or Pressurized Rover walls, recharge of the space suit backpack and emergency situations. Current plans indicate that both primary and secondary O2 bottles for the space suit will be filled to a pressure of 20.7 MPa (3000 psia). Other uses of O2 require much lower pressure. Sources of O2 at a Lunar Outpost include compressed or liquefied O2 brought along specifically for life support, scavenged O2 from the Lander propulsion system, recovered O2 from waste water or exhaled carbon dioxide and O2 mined from the moon itself. Previously, eight technology options were investigated to provide the high pressure space suit O2. High pressure O2 storage was treated as the baseline technology and compared to the other seven. The other seven were cryogenic storage followed by high pressure vaporization, scavenging liquid oxygen (LOX) from Lander followed by vaporization, LOX delivery followed by sorption compression, low pressure water electrolysis followed by mechanical compression, high pressure water electrolysis, sharing a high pressure electrolyzer with a regenerative fuel cell power system, and making use of In- Situ Resource Utilization (ISRU). This system-level analysis was conducted by comparing equivalent system mass of the eight technologies in open and closed loop life support architectures. The most promising high pressure O2 generation technologies were recommended for development. Updates and an expansion of the earlier study have been made and the results are reported in

Meal frequency patterns and glycemic properties of maternal diet in relation to preterm delivery: Results from a large prospective cohort study.

Directory of Open Access Journals (Sweden)

Linda Englund-Ögge

Full Text Available Dietary habits are linked to high maternal glucose levels, associated with preterm delivery. The aim of this study was to examine the associations between meal frequency and glycemic properties of maternal diet in relation to preterm delivery.This prospective cohort study included 66,000 women from the Norwegian Mother and Child Cohort Study (MoBa. Meal frequency and food intake data were obtained from a validated food frequency questionnaire during mid-pregnancy. Principal component factor analysis was used with a data-driven approach, and three meal frequency patterns were identified: "snack meal", "main meal", and "evening meal". Pattern scores were ranked in quartiles. Glycemic index and glycemic load were estimated from table values. Intakes of carbohydrates, added sugar, and fiber were reported in grams per day and divided into quartiles. Gestational age was obtained from the Medical Birth Registry of Norway. Preterm delivery was defined as birth at <37 gestational weeks. A Cox regression model was used to assess associations with preterm delivery.After adjustments, the "main meal" pattern was associated with a reduced risk of preterm delivery, with hazard ratios (HRs of 0.89 (95% confidence interval (CI: 0.80, 0.98 and 0.90 (95% CI: 0.81, 0.99 for the third and fourth quartiles, respectively, and p for trend of 0.028. This was mainly attributed to the group of women with BMI ≥25 kg/m2, with HRs of 0.87 (95% CI: 0.79, 0.96 and 0.89 (95% CI: 0.80, 0.98 for the third and fourth quartiles, respectively, and p for trend of 0.010. There was no association between glycemic index, glycemic load, carbohydrates, added sugar, fiber, or the remaining meal frequency patterns and preterm delivery.Regular consumption of main meals (breakfast, lunch, dinner was associated with a lower risk of preterm delivery. Diet should be further studied as potential contributing factors for preterm delivery.

11-Oxygenated C19 Steroids Are the Predominant Androgens in Polycystic Ovary Syndrome.

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O'Reilly, Michael W; Kempegowda, Punith; Jenkinson, Carl; Taylor, Angela E; Quanson, Jonathan L; Storbeck, Karl-Heinz; Arlt, Wiebke

2017-03-01

Androgen excess is a defining feature of polycystic ovary syndrome (PCOS), but the exact origin of hyperandrogenemia remains a matter of debate. Recent studies have highlighted the importance of the 11-oxygenated C19 steroid pathway to androgen metabolism in humans. In this study, we analyzed the contribution of 11-oxygenated androgens to androgen excess in women with PCOS. One hundred fourteen women with PCOS and 49 healthy control subjects underwent measurement of serum androgens by liquid chromatography-tandem mass spectrometry. Twenty-four-hour urinary androgen excretion was analyzed by gas chromatography-mass spectrometry. Fasting plasma insulin and glucose were measured for homeostatic model assessment of insulin resistance. Baseline demographic data, including body mass index, were recorded. As expected, serum concentrations of the classic androgens testosterone (P PCOS. Mirroring this, serum 11-oxygenated androgens 11β-hydroxyandrostenedione, 11-ketoandrostenedione, 11β-hydroxytestosterone, and 11-ketotestosterone were significantly higher in PCOS than in control subjects, as was the urinary 11-oxygenated androgen metabolite 11β-hydroxyandrosterone. The proportionate contribution of 11-oxygenated to total serum androgens was significantly higher in patients with PCOS compared with control subjects [53.0% (interquartile range, 48.7 to 60.3) vs 44.0% (interquartile range, 32.9 to 54.9); P PCOS had significantly increased 11-oxygenated androgens. Serum 11β-hydroxyandrostenedione and 11-ketoandrostenedione correlated significantly with markers of insulin resistance. We show that 11-oxygenated androgens represent the majority of circulating androgens in women with PCOS, with close correlation to markers of metabolic risk.

Water quality index and eutrophication indices of Caiabi River, MT

Directory of Open Access Journals (Sweden)

Grasiane Andrietti

2016-03-01

Full Text Available The objective of this study was to evaluate the water quality of the Caiabi River based upon the water quality index (WQI and the trophic state index (TSI, considering seasonal and spatial variations, with the aim of determining the most appropriate monitoring design for this study site. Sampling for water quality monitoring was conducted at five points on the Caiabi River from July 2012 to June 2013. Quality parameters quantified were as follows: pH, temperature, conductivity, dissolved oxygen, total and thermotolerant coliforms, turbidity, Kjeldahl nitrogen, nitrite, nitrate, total phosphorus, biochemical oxygen demand, series of solids, and chlorophyll a. Sampling procedures and analysis followed the methods recommended by the Standard Methods for the Examination of Water and Wastewater. The WQI results showed that the quality of the Caiabi River water is good. TSI results demonstrated the low risk of eutrophication in the Caiabi River, indicating an ultra-oligotrophic lotic environment. Analysis of variance showed that 10 of the 16 monitored quality parameters presented differences of means between the dry and rainy seasons or among the monitored points or in the interaction between seasons and points. These results indicate that two annual sampling collections at two points may be sufficient to describe the water quality behavior in the basin, as long as the conditions of land use are stable.

Thermographic analysis of photodynamic therapy with intense pulsed light and needle-free injection photosensitizer delivery: an animal study

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Requena, Michelle B.; Stringasci, Mirian D.; Pratavieira, Sebastião.; Vollet-Filho, José Dirceu; de Nardi, Andrigo B.; Escobar, Andre; da Rocha, Rozana W.; Bagnato, Vanderlei S.; de Menezes, Priscila F. C.

2018-02-01

The photodynamic therapy (PDT) is a therapeutic modality that depends mostly on photosensitizer (PS), light and molecular oxygen species. However, there are still technical limitations in clinical PDT that are under constant development, particularly concerning PS and light delivery. Intense Pulsed Light (IPL) sources are systems able to generate pulses of high energy with polychromatic light. IPL is a technique mainly used in the cosmetic area to perform various skin treatments for therapeutic and aesthetic applications. The goals of this study were to determine temperature variance during the application of IPL in porcine skin model, and the PDT effects using this light source with PS delivery by a commercial high pressure, needle-free injection system. The PSs tested were Indocyanine Green (ICG) and Photodithazine (PDZ), and the results showed an increase bellow 10 °C in the skin surface using a thermographic camera to measure. In conclusion, our preliminary study demonstrated that IPL associated with needle-free injection PS delivery could be a promising alternative to PDT.

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.

Methanol Droplet Extinction in Oxygen/Carbon-dioxide/Nitrogen Mixtures in Microgravity: Results from the International Space Station Experiments

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Nayagam, Vedha; Dietrich, Daniel L.; Ferkul, Paul V.; Hicks, Michael C.; Williams, Forman A.

2012-01-01

Motivated by the need to understand the flammability limits of condensed-phase fuels in microgravity, isolated single droplet combustion experiments were carried out in the Combustion Integrated Rack Facility onboard the International Space Station. Experimental observations of methanol droplet combustion and extinction in oxygen/carbon-dioxide/nitrogen mixtures at 0.7 and 1 atmospheric pressure in quiescent microgravity environment are reported for initial droplet diameters varying between 2 mm to 4 mm in this study.The ambient oxygen concentration was systematically lowered from test to test so as to approach the limiting oxygen index (LOI) at fixed ambient pressure. At one atmosphere pressure, ignition and some burning were observed for an oxygen concentration of 13% with the rest being nitrogen. In addition, measured droplet burning rates, flame stand-off ratios, and extinction diameters are presented for varying concentrations of oxygen and diluents. Simplified theoretical models are presented to explain the observed variations in extinction diameter and flame stand-off ratios.

Measuring oxygen tension modulation, induced by a new pre-radiotherapy therapeutic, in a mammary window chamber mouse model

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Schafer, Rachel; Gmitro, Arthur F.

2015-03-01

Tumor regions under hypoxic or low oxygen conditions respond less effectively to many treatment strategies, including radiation therapy. A novel investigational therapeutic, NVX-108 (NuvOx Pharma), has been developed to increase delivery of oxygen through the use of a nano-emulsion of dodecofluoropentane. By raising pO2 levels prior to delivering radiation, treatment efficacy may be improved. To aid in evaluating the novel drug, oxygen tension was quantitatively measured, spatially and temporally, to record the effect of administrating NVX-108 in an orthotopic mammary window chamber mouse model of breast cancer. The oxygen tension was measured through the use of an oxygen-sensitive coating, comprised of phosphorescent platinum porphyrin dye embedded in a polystyrene matrix. The coating, applied to the surface of the coverslip of the window chamber through spin coating, is placed in contact with the mammary fat pad to record the oxygenation status of the surface tissue layer. Prior to implantation of the window chamber, a tumor is grown in the SCID mouse model by injection of MCF-7 cells into the mammary fat pad. Two-dimensional spatial distributions of the pO2 levels were obtained through conversion of measured maps of phosphorescent lifetime. The resulting information on the spatial and temporal variation of the induced oxygen modulation could provide valuable insight into the optimal timing between administration of NVX-108 and radiation treatment to provide the most effective treatment outcome.

Toward Understanding Mechanisms Controlling Urea Delivery in a Coastal Plain Watershed

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Tzilkowski, S. S.; Buda, A. R.; Boyer, E. W.; Bryant, R. B.; May, E. B.

2012-12-01

dry (5-day antecedent precipitation index = 0 mm), we observed an anticlockwise hysteresis pattern and a delayed, yet high, peak in urea concentrations (0.17 mg L-1) on the falling limb of the hydrograph. These trends suggest that urea was delivered via slow, diffuse flow pathways and from sources distal from the sampling point. In contrast, during a less intense (3.2 mm hr-1), longer duration (22 hrs) storm in October of 2010 when antecedent conditions were wetter (5-day antecedent precipitation index = 67.31 mm), we observed a clockwise hysteresis pattern and a smaller peak in urea concentrations (0.06 mg L-1) timed with the hydrograph peak. Here, the trends suggest that urea delivery occurred through faster flow pathways (e.g., shallow lateral flow) and from proximal (e.g., near-stream, in-stream) sources of urea. Collectively, these trends demonstrate that urea is flushed to streams during storm events, but that the mechanism for delivery depends on antecedent conditions, as well as the nature of the storm event.

Liquid crystal nanoparticles for delivery of photosensitizers for photodynamic therapy

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Nag, Okhil K.; Naciri, Jawad; Delehanty, James B.

2018-02-01

The main principle of photodynamic therapy (PDT) is to kill malignant cells by generation of reactive oxygen species (ROS). PDT appeared highly effective when ROS can be produced in subcellular location such as plasma membrane. The plasma membrane maintains the structural integrity of the cell and regulates multiple important cellular processes, such as endocytosis, trafficking, and apoptotic pathways, could be one of the best points to kill the cancer cells. Previously, we have developed a plasma membrane-targeted liquid crystal nanoparticle (LCNP) formulation that can be loaded with dyes or drugs. Here we highlight the utility of this LCNP for membrane targeted delivery and imaging for a photosensitizer (PS) for PDT applications.

Wobbe index control system in gas industry processes; Systeme de controle de l'index de Wobbe du gaz naturel dans les processus industriels

Energy Technology Data Exchange (ETDEWEB)

Cassibba, M.; Bertani, M. [SNAM, (Italy)

2000-07-01

Natural gas supplied to industry for process utilizations originates from different sources and that can cause fluctuations in gas composition. Changing gas composition may lead to production problems in industry with sensitive thermal processes (particularly glass industry and thermal metal treatments), such as efficiency and product quality. An equipment suitable to control and adjust such variations has been developed. Experimental tests in laboratory were carried out in order to investigate the control system accuracy and reliability. In particular five different settings were tested: at a preset thermal input by adjusting the natural gas flow rate in respect to Wobbe Index variations; at a set furnace temperature and stack oxygen level with variable thermal input by monitoring the Wobbe Index value; at constant Wobbe Index value by adding air to natural gas; at constant thermal input and prefixed Wobbe Index value by adding air to natural gas and varying the air and gas mixture flow rate; gross calorific value control by adding air or LPG to natural gas. All the tested settings gave good results. This report illustrates these results and the main features of the control system. The control and regulation system was installed in two glass factories for field tests. (authors)

Characterization of water quality and simulation of temperature, nutrients, biochemical oxygen demand, and dissolved oxygen in the Wateree River, South Carolina, 1996-98

Science.gov (United States)

Feaster, Toby D.; Conrads, Paul

2000-01-01

and validate the Branched Lagrangian Transport Model. The data include dye-tracer concentrations collected at six locations, stream-reaeration data collected at four locations, and water-quality and water-temperature data collected at nine locations. Hydraulic data for the Branched Lagrangian Transport Model were simulated by using the U.S. Geological Survey BRANCH one-dimensional, unsteady-flow model. Data that were used to calibrate and validate the BRANCH model included time-series of water-level and streamflow data at three locations. The domain of the hydraulic model and the transport model was a 57.3- and 43.5-mile reach of the river, respectively. A sensitivity analysis of the simulated dissolved-oxygen concentrations to model coefficients and data inputs indicated that the simulated dissolved-oxygen concentrations were most sensitive to changes in the boundary concentration inputs of water temperature and dissolved oxygen followed by sensitivity to the change in streamflow. A 35-percent increase in streamflow resulted in a negative normalized sensitivity index, indicating a decrease in dissolved-oxygen concentrations. The simulated dissolved-oxygen concentrations showed no significant sensitivity to changes in model input rate kinetics. To demonstrate the utility of the Branched Lagrangian Transport Model of the Wateree River, the model was used to simulate several hydrologic and water-quality scenarios to evaluate the effects on simulated dissolved-oxygen concentrations. The first scenario compared the 24-hour mean dissolved-oxygen concentrations for August 13, 1997, as simulated during the model validation, with simulations using two different streamflow patterns. The mean streamflow for August 13, 1997, was 2,000 cubic feet per second. Simulations were run using mean streamflows of 1,000 and 1,400 cubic feet per second while keeping the water-quality boundary conditions the same as were used during the validation simulations. When compared t

A new smoothing procedure to reduce delivery segments for static MLC-based IMRT planning

International Nuclear Information System (INIS)

Sun Xuepeng; Xia Ping

2004-01-01

In the application of pixel-based intensity-modulated radiation therapy (IMRT) using the step-and-shoot delivery method, one major difficulty is the prolonged delivery time. In this study, we present an integrated IMRT planning system that involves a simple smoothing method to reduce the complexity of the beam profiles. The system consists of three main steps: (a) an inverse planning process based on a least-square dose-based cost function; (b) smoothing of the intensity maps; (c) reoptimization of the segment weights. Step (a) obtains the best plan with the lowest cost value using a simulated annealing optimization algorithm with discrete intensity levels. Step (b) takes the intensity maps obtained from (a) and reduces the complexity of the maps by smoothing the adjacent beamlet intensities. During this process each beamlet is assigned a structure index based on anatomical information. A smoothing update is applied to average adjacent beamlets with the same index. To control the quality of the plan, a predefined clinical protocol is used as an acceptance criterion. The smoothing updates that violate the criterion are rejected. After the smoothing process, the segment weights are reoptimized in step (c) to further improve the plan quality. Three clinical cases were studied using this system: a medulloblastoma, a prostate cancer, and an oropharyngeal carcinoma. While the final plans demonstrate a degradation of the original plan quality, they still meet the plan acceptance criterion. On the other hand, the segment numbers or delivery times are reduced by 40%, 20%, and 20% for the three cases, respectively

Oxygen-Partial-Pressure Sensor for Aircraft Oxygen Mask

Science.gov (United States)

Kelly, Mark; Pettit, Donald

2003-01-01

A device that generates an alarm when the partial pressure of oxygen decreases to less than a preset level has been developed to help prevent hypoxia in a pilot or other crewmember of a military or other high-performance aircraft. Loss of oxygen partial pressure can be caused by poor fit of the mask or failure of a hose or other component of an oxygen distribution system. The deleterious physical and mental effects of hypoxia cause the loss of a military aircraft and crew every few years. The device is installed in the crewmember s oxygen mask and is powered via communication wiring already present in all such oxygen masks. The device (see figure) includes an electrochemical sensor, the output potential of which is proportional to the partial pressure of oxygen. The output of the sensor is amplified and fed to the input of a comparator circuit. A reference potential that corresponds to the amplified sensor output at the alarm oxygen-partial-pressure level is fed to the second input of the comparator. When the sensed partial pressure of oxygen falls below the minimum acceptable level, the output of the comparator goes from the low state (a few millivolts) to the high state (near the supply potential, which is typically 6.8 V for microphone power). The switching of the comparator output to the high state triggers a tactile alarm in the form of a vibration in the mask, generated by a small 1.3-Vdc pager motor spinning an eccentric mass at a rate between 8,000 and 10,000 rpm. The sensation of the mask vibrating against the crewmember s nose is very effective at alerting the crewmember, who may already be groggy from hypoxia and is immersed in an environment that is saturated with visual cues and sounds. Indeed, the sensation is one of rudeness, but such rudeness could be what is needed to stimulate the crewmember to take corrective action in a life-threatening situation.

Improved overall delivery documentation following implementation of a standardized shoulder dystocia delivery form

Science.gov (United States)

Moragianni, Vasiliki A.; Hacker, Michele R.; Craparo, Frank J.

2013-01-01

Objective Our objective was to evaluate whether using a standardized shoulder dystocia delivery form improved documentation. A standardized delivery form was added to our institution’s obstetrical record in August 2003. Methods A retrospective cohort study was conducted comparing 100 vaginal deliveries complicated by shoulder dystocia before, and 81 after implementation of the standardized delivery form. The two groups were compared in terms of obstetric characteristics, neonatal outcomes and documentation components. Results Charts that included the standardized delivery form were more likely to contain documentation of estimated fetal weight (82.7% vs. 39.0% without the form, Pdystocia, and second stage duration. Conclusions Inclusion of a standardized form in the delivery record improves the rate of documentation of both shoulder dystocia-specific and general delivery components. PMID:22017330

Oxygen pathway modeling estimates high reactive oxygen species production above the highest permanent human habitation.

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Isaac Cano

Full Text Available The production of reactive oxygen species (ROS from the inner mitochondrial membrane is one of many fundamental processes governing the balance between health and disease. It is well known that ROS are necessary signaling molecules in gene expression, yet when expressed at high levels, ROS may cause oxidative stress and cell damage. Both hypoxia and hyperoxia may alter ROS production by changing mitochondrial Po2 (PmO2. Because PmO2 depends on the balance between O2 transport and utilization, we formulated an integrative mathematical model of O2 transport and utilization in skeletal muscle to predict conditions to cause abnormally high ROS generation. Simulations using data from healthy subjects during maximal exercise at sea level reveal little mitochondrial ROS production. However, altitude triggers high mitochondrial ROS production in muscle regions with high metabolic capacity but limited O2 delivery. This altitude roughly coincides with the highest location of permanent human habitation. Above 25,000 ft., more than 90% of exercising muscle is predicted to produce abnormally high levels of ROS, corresponding to the "death zone" in mountaineering.

The Relationship between Mode of Delivery and Sexual Function in Nulliparous Women

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Aytay Alesheikh

2016-07-01

Full Text Available Background & aim: Sexual activity is one of the most important aspects of a marital life. Childbirth is also a major event in the life of women, and the period of postpartum is a time of emotional upheaval. Since women believe that vaginal delivery could negatively affect their sexual function after childbirth, they tend to give birth through caesarean section. Therefore, this study aimed to evaluate the relationship between mode of delivery and sexual function in nulliparous women referred to healthcare centers in Mashhad, Iran. Methods: This correlational study was conducted on 450 nulliparous women, divided into two groups of vaginal delivery and cesarean section in 2014. Suubjects were selected via multistage sampling. Data collection tools included Female Sexual Function Index (FSFI, Depression, Anxiety and Stress scale (DASS-21, and Cassidy social support scale. Data was analyzed in SPSS version 16 using Spearman correlation coefficient and Mann-Whitney test, T-test, ANOVA, and Kruskal-Wallis. Moreover, general linear model was used to control confounding variables, and P-value of less than 0.05 was considered statistically significant. Results: Independent t-test results indicated that mean scores of sexual function in two groups of the study were 26.11±4.36 and 26.38±4.41, respectively, which revealed no statistically significant difference between the groups (P=0.509. Conclusion: No significant difference was observed between the vaginal delivery and caesarean section groups regarding sexual function. Therefore, it seems that cesarean section does not necessarily lead to pleasing sexual relationships in postpartum period compared to vaginal delivery.

Effects of hyperbaric oxygen and normobaric carbogen on the radiation response of the rat rhabdomyosarcoma R1H

International Nuclear Information System (INIS)

Hartmann, K. Axel; Kleij, Ad J. van der; Carl, Ulrich M.; Hulshof, Maarten C.C.M.; Willers, Reinhart; Sminia, Peter

2001-01-01

Purpose: Hypoxic tumor cells are an important factor of radioresistance. Hyperbaric oxygen (HBO) and normobaric carbogen (95% oxygen, 5% carbon dioxide) increase the oxygen delivery to tumors. This study was performed to explore changes of tumor oxygenation during a course of fractionated irradiation and to determine the effectiveness of normobaric carbogen and HBO during the final phase of the radiation treatment. Methods and Materials: Experiments were performed on the rhabdomyosarcoma R1H growing on WAG/Rij rats. After 20 X-ray fractions of 2 Gy within 4 weeks, oxygen partial pressure (pO 2 ) was measured using the Eppendorf oxygen electrode under ambient conditions, with normobaric carbogen or HBO at a pressure of 240 kPa. Following the 4-week radiation course, a top-up dose of 10-50 Gy was applied in 2-10 fractions of 5 Gy with or without hyperoxygenation. Results: HBO but not carbogen significantly increased the median pO 2 in irradiated tumors. The radiation doses to control 50% of tumors were 38.0 Gy, 29.5 Gy, and 25.0 Gy for air, carbogen, and HBO, respectively. Both high oxygen content gas inspirations led to significantly improved tumor responses with oxygen enhancement ratios (OERs) of 1.3 for normobaric carbogen and 1.5 for HBO (air vs. carbogen: p=0.044; air vs. HBO: p=0.02; carbogen vs. HBO: p=0.048). Conclusion: Both normobaric carbogen and HBO significantly improved the radiation response of R1H tumors. HBO appeared to be more effective than normobaric carbogen, both with regard to tumor oxygenation and response to irradiation

Development and assessment of a distribution network of hydro-methane, methanol, oxygen and carbon dioxide in Paraguay

International Nuclear Information System (INIS)

Rivarolo, M.; Marmi, S.; Riveros-Godoy, G.; Magistri, L.

2014-01-01

Highlights: • We investigate different transporting modes of hydro-methane, methanol, CO 2 and O 2 . • We determine the best transportation technology from an economic point of view. • The best pathway to distribute the hydro-methane depends on quantity and distance. • Methanol distribution presents the lowest cost delivery. - Abstract: This paper summarizes key results of the analysis of different transport modes of hydro-methane, methanol, carbon dioxide and oxygen in Paraguay, Brazil and Argentina. Hydro-methane is produced in Paraguay and can be used to fuel natural gas vehicles, substituting gasoline and diesel which are at the moment imported from foreign countries. Methanol, also produced in Paraguay, is delivered to Brazil, which is one of the Countries with the highest demand in the region. Oxygen can be sold to Argentina for medical and industrial use. Carbon dioxide is delivered throughout Paraguay. The aim of this study is to determine the best transportation technology from an economic and strategic point of view, minimizing costs associated to products distribution. Several scenarios are investigated; each scenario is associated with different delivery modes. A model is developed to estimate both capital and variable costs for different transportation technologies (pipeline, trucks, ships) in order to choose the lowest-cost delivery mode for each product, depending on distances and flow rates. Four different analysis are performed for each scenario, varying the number of vehicles which must be fueled by hydro-methane and considering its influence on the results. The methodology presented here has a general value, thus it can be easily employed for the economic analysis of different fuels and distribution networks, also placed in different scenarios

Multifunctional Nanoparticles for Drug Delivery Applications Imaging, Targeting, and Delivery

CERN Document Server

Prud'homme, Robert

2012-01-01

This book clearly demonstrates the progression of nanoparticle therapeutics from basic research to applications. Unlike other books covering nanoparticles used in medical applications, Multifunctional Nanoparticles for Drug Delivery Applications presents the medical challenges that can be reduced or even overcome by recent advances in nanoscale drug delivery. Each chapter highlights recent progress in the design and engineering of select multifunctional nanoparticles with topics covering targeting, imaging, delivery, diagnostics, and therapy.

Total quality index of Agaricus bisporus mushrooms packed in modified atmosphere.

Science.gov (United States)

Djekic, Ilija; Vunduk, Jovana; Tomašević, Igor; Kozarski, Maja; Petrovic, Predrag; Niksic, Miomir; Pudja, Predrag; Klaus, Anita

2017-07-01

The aim of this study was to develop a total quality index and examine the effects of modified atmosphere packaging (MAP) on the quality of Agaricus bisporus mushrooms stored for 22 days at 4 °C. Mushrooms were packaged under three MAPs: high nitrogen packaging (HNP), low carbon dioxide packaging (LCP) and low oxygen packaging (LOP). Passive MAP with air inside initially was used as the atmosphere treatment (AIR). This research revealed two phases in quality deterioration of A. bisporus mushrooms. During the first week, most of the quality parameters were not statistically different. Thereafter, odor intensities were stronger for all four types of packaging. Color difference and browning index values showed significantly lower color changes for AIR and LOP compared with HNP and LCP mushrooms. The best total quality index was calculated for LOP, followed by LCP and AIR. The findings of this study are useful with respect to examining two-component MAPs, separating the limiting factors (O 2 and CO 2 ) and evaluating quality deterioration effects and the total quality index of A. bisporus mushrooms. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

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

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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.

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

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Qi, Xuejun; Song, Wenwu; Shi, Jianwei

2017-01-01

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

Primary caregivers of in-home oxygen-dependent children: predictors of stress based on characteristics, needs and social support.

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Wang, Kai-Wei K; Lin, Hung-Ching; Lee, Chin-Ting; Lee, Kuo-Sheng

2016-07-01

To identify the predictors of primary caregivers' stress in caring for in-home oxygen-dependent children by examining the association between their levels of stress, caregiver needs and social support. Increasing numbers of primary caregivers of oxygen-dependent children experience caregiving stress that warrants investigation. The study used a cross-sectional design with three psychometric scales - Modified-Parenting Stress Index, Caregiver Needs Scale and Social Support Index. The data collected during 2010-2011 were from participants who were responsible for their child's care that included oxygen therapy for ≧6 hours/day; the children's ages ranged from 3 months-16 years. Descriptive statistics and multivariable linear regression were used. A total of 104 participants (M = 34, F = 70) were recruited, with an average age of 39·7 years. The average age of the oxygen-dependent children was 6·68 years and their daily use of oxygen averaged 11·39 hours. The caregivers' overall levels of stress were scored as high and information needs were scored as the highest. The most available support from family and friends was emotional support. Informational support was mostly received from health professionals, but both instrumental and emotional support were important. Levels of stress and caregiver needs were significantly correlated. Multivariable linear regression analyses identified three risk factors predicting stress, namely, the caregiver's poor health status, the child's male gender and the caregiver's greater financial need. To support these caregivers, health professionals can maintain their health status and provide instrumental, emotional, informational and financial support. © 2016 John Wiley & Sons Ltd.

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.

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...

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

Science.gov (United States)

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

2016-01-01

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

Colloidal drug delivery system: amplify the ocular delivery.

Science.gov (United States)

Ali, Javed; Fazil, Mohd; Qumbar, Mohd; Khan, Nazia; Ali, Asgar

2016-01-01

The ocular perceivers are the most voluntarily accessible organs in terms of location in the body, yet drug distribution to these tissues is one of the most intriguing and challenging endeavors and problematic to the pharmaceutical scientist. The most of ocular diseases are treated with topical application of conventional formulation, i.e. solutions, suspensions and ointment. Typically on installation of these conventional formulations, only <5% of the applied dose penetrates the cornea and reaches intraocular tissues, while a major fraction of the instilled dose is wastage due to the presence of many ocular barriers like external barriers, rapid loss of the instilled solution from the precorneal area and nasolacrimal drainage system. Systemic absorption caused systemic side effects varying from mild to life-threatening events. The main objective of this review is to explore the role of colloidal delivery of drug to minimize the drawbacks associated with them. This review provides an insight into the various constraints associated with ocular drug delivery, summarizes recent findings and applications of colloidal delivery systems, i.e. nanoparticles, nanosuspensions, liposomes, niosomes, dendrimers and contact lenses containing nanoparticles have the capacity to distribute ocular drugs to categorical target sites and hold promise to revolutionize the therapy of many ocular perceiver diseases and minimized the circumscription of conventional delivery. Form the basis of literature review, it has been found that the novel delivery system have greater impact to maximize ocular drug absorption, and minimize systemic absorption and side effects.

Oxygen delivery to the fish eye: root effect as crucial factor for elevated retinal PO2.

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Waser, W; Heisler, N

2005-11-01

Although the retina has one of the highest metabolic rates among tissues, certain teleost fishes lack any vascular supply to this organ which, in combination with the overall thickness of the organ, results in extremely long diffusion distances. As the only way to compensate for these obstacles, oxygen partial pressure (PO2) in the eyes of such fish is elevated far above atmospheric values. Although not supported by any direct evidence, the enhancement of PO2 is considered to be related to the Root effect, the release upon acidification of Hb-bound O2 into physical dissolution, possibly supported by counter-current multiplication similar to the loop of Henle. The present study evaluates the magnitude of intraocular PO2 enhancement under tightly controlled physiological conditions, to directly confirm the involvement of the Root effect on intraocular PO2 in the retina of rainbow trout Oncorhynchus mykiss. Intraocular PO2 was determined with special polarographic microelectrodes inserted into the eye. PO2 profiles established in vivo by driving electrodes through the entire retina yielded average PO2 values between 10 mmHg (1.3 kPa) at the inner retinal surface and 382 mmHg (50.9 kPa) close to the outer retinal limit (Bruch's membrane). According to estimates on the basis of the diffusion distances determined from sections of the retina (approximately 436 microm at the site of PO2 measurement) and literature data on specific oxygen consumption, the in vivo determined values would be sufficient to cover the oxygen demand of the retina with some safety margin. For a clear and direct in-tissue-test as to the involvement of the Root effect, an isolated in vitro eye preparation was established in order to avoid the problem of indirect blood supply to the eye from the dorsal aorta only via the pseudobranch, a hemibranch thought to modulate blood composition before entry of the eye. Any humoral effects (e.g. catecholamines) were eliminated by perfusing isolated eyes

Hybrid configurations via percutaneous access for extracorporeal membrane oxygenation: a single-center experience.

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Biscotti, Mauer; Lee, Alison; Basner, Robert C; Agerstrand, Cara; Abrams, Darryl; Brodie, Daniel; Bacchetta, Matthew

2014-01-01

Use of extracorporeal membrane oxygenation (ECMO) in adults has surged in recent years. Typical configurations are venovenous (VV), which provides respiratory support, or venoarterial (VA), which provides both respiratory and circulatory support. In patients supported with VV ECMO who develop hemodynamic compromise, an arterial limb can be added (venovenous-arterial ECMO) to provide additional circulatory support. For patients on VA ECMO who develop concomitant respiratory failure in the setting of some residual cardiac function, an oxygenated reinfusion limb can be added to the internal jugular vein (venoarterial-venous ECMO) to improve oxygen delivery to the cerebral and coronary circulation. Such hybrid configurations can provide differential support for various forms of cardiopulmonary failure. We describe 21 patients who ultimately received a hybrid configuration at our institution between 2012 and 2013. Eight patients (38.1%) died during ECMO support, four patients (19.0%) died after decannulation but before hospital discharge, and nine patients (42.9%) survived to hospital discharge. Our modest survival rate is likely related to the complexity and severity of illness of these patients, and this relative success suggests that hybrid configurations can be effective. It serves patients well to maintain a flexible and adaptable approach to ECMO configurations for their variable cardiopulmonary needs.

Comparing the Efficacy of Face Mask CPAP with Nasopharyngeal CPAP for Neonatal Transport after Delivery

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Manizheh Mostafa-Gharehbaghi

2013-09-01

Full Text Available Background: Preterm infants have respiratory failure and complications because surfactant in alveolus is low. CPAP (Continuous positive airway pressure is a method for respiratory support in pre-term neonates and is provided by different equipment and methods. This study aims to compare two different routes of CPAP delivery in preterm newborn infants and to determine the need for surfactant replacement therapy in two groups. Materials and Methods: This is a randomized controlled clinical trial. Eighty four preterm infants delivered in Al-Zahra Hospital with gestational age 28-32 weeks were enrolled in this study from January 2012 to September 2012. They were randomly allocated in two groups. After initial stabilization in delivery room, forty two infants transferred to neonatal intensive care unit (NICU with face mask CPAP and 42 infant with nasopharyngeal CPAP and continued nasal CPAP in the NICU in both groups. All infants were followed for developing respiratory distress and need for surfactant replacement therapy and oxygen dependency till discharge.Results: The neonates that treated with two methods of CPAP delivery were similar with respect to gestation age, birth weight and other demographic characteristics. Twenty three neonates (65.5% in face mask group and 15 neonates (39.5% in nasopharyngeal CPAP group need surfactant replacement therapy (p=0.08.Conclusion: Mask CPAP or nasopharyngeal CPAP can used in preterm infants after delivery for neonatal transfer to NICU. This study showed no method of CPAP delivery is preferable to other in decreasing the need for surfactant therapy.

Bayesian prediction of microbial oxygen requirement [v1; ref status: indexed, http://f1000r.es/1m6

Directory of Open Access Journals (Sweden)

Dan B. Jensen

2013-09-01

Full Text Available Background: Prediction of the optimal habitat conditions for a given bacterium, based on genome sequence alone would be of value for scientific as well as industrial purposes. One example of such a habitat adaptation is the requirement for oxygen. In spite of good genome data availability, there have been only a few prediction attempts of bacterial oxygen requirements, using genome sequences. Here, we describe a method for distinguishing aerobic, anaerobic and facultative anaerobic bacteria, based on genome sequence-derived input, using naive Bayesian inference. In contrast, other studies found in literature only demonstrate the ability to distinguish two classes at a time. Results: The results shown in the present study are as good as or better than comparable methods previously described in the scientific literature, with an arguably simpler method, when results are directly compared. This method further compares the performance of a single-step naive Bayesian prediction of the three included classifications, compared to a simple Bayesian network with two steps. A two-step network, distinguishing first respiring from non-respiring organisms, followed by the distinction of aerobe and facultative anaerobe organisms within the respiring group, is found to perform best. Conclusions: A simple naive Bayesian network based on the presence or absence of specific protein domains within a genome is an effective and easy way to predict bacterial habitat preferences, such as oxygen requirement.

Neonatal outcomes and operative vaginal delivery versus cesarean delivery.

LENUS (Irish Health Repository)

Contag, Stephen A

2010-06-01

We compared outcomes for neonates with forceps-assisted, vacuum-assisted, or cesarean delivery in the second stage of labor. This is a secondary analysis of a randomized trial in laboring, low-risk, nulliparous women at >or=36 weeks\\' gestation. Neonatal outcomes after use of forceps, vacuum, and cesarean were compared among women in the second stage of labor at station +1 or below (thirds scale) for failure of descent or nonreassuring fetal status. Nine hundred ninety women were included in this analysis: 549 (55%) with an indication for delivery of failure of descent and 441 (45%) for a nonreassuring fetal status. Umbilical cord gases were available for 87% of neonates. We found no differences in the base excess (P = 0.35 and 0.78 for failure of descent and nonreassuring fetal status) or frequencies of pH below 7.0 (P = 0.73 and 0.34 for failure of descent and nonreassuring fetal status) among the three delivery methods. Birth outcomes and umbilical cord blood gas values were similar for those neonates with a forceps-assisted, vacuum-assisted, or cesarean delivery in the second stage of labor. The occurrence of significant fetal acidemia was not different among the three delivery methods regardless of the indication.

Assisted delivery with forceps

Science.gov (United States)

... page: //medlineplus.gov/ency/patientinstructions/000509.htm Assisted delivery with forceps To use the sharing features on ... called vacuum assisted delivery . When is a Forceps Delivery Needed? Even after your cervix is fully dilated ( ...