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Results 251 - 300 of 973
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Nakada Masakatsu - - 2004
The purpose of this study was to clarify the kinetics of muscle oxygenation by near infrared spectroscopy (NIRS) in the phase of the decreasing force, especially the pre- and post-phases of the inflection point, during repeated rhythmic grip (RRG) of 30 grips/min(-1) for 6 minutes. The inflection point was the ...
McGuire B J - - 2004
A Krogh-type model for oxygen transport is used to predict maximal oxygen consumption (V(.-) O(2max)) of human skeletal muscle under hypoxic conditions. Assumed values of capillary density, blood flow, and hemoglobin concentration are based on measurements under normoxic and hypoxic exercise conditions. Arterial partial pressure of oxygen is assumed to ...
Schwarte Lothar A - - 2005
Acute normovolemic hemodilution (ANH) compromizes intestinal microcirculatory oxygenation; however, the underlying mechanisms are incompletely understood. We hypothesized that contributors herein include redistribution of oxygen away from the intestines and shunting of oxygen within the intestines. The latter may be due to the impaired ability of erythrocytes to off-load oxygen within ...
Wettstein Reto - - 2004
Our aim was to determine the efficacy of polyethylene glycol-conjugated human albumin (MalPEG-Alb) in restoring circulatory volume after 1 h of hemorrhagic shock. Experiments were performed in the awake condition in the hamster skin fold preparation. Microhemodynamic parameters and tissue Po2 were assessed with intravital microscopy and the use of ...
Johnson Karen L - - 2004
Accurate assessment and treatment of disturbances in oxygenation are crucial to optimal outcomes in critically ill patients. Oxygenation is dependent upon adequate pulmonary gas exchange, oxygen delivery, and oxygen consumption. Each of these physiologic processes may vary independently in response to pathophysiologic conditions and therapeutic interventions. The author reviews diagnostic ...
Fuhrman C - - 2004
OBJECTIVES: The aim of this study was to assess the performance of four demand oxygen delivery systems (DODS) in improving oxygenation and effort tolerance, at rest and during exercise, in chronic obstructive pulmonary disease (COPD) patients. MATERIALS AND METHODS: Thirteen COPD patients were prospectively included. Four DODS (Oxiclip, Versatile, Venture ...
Barros Mario H - - 2004
Increased replicative longevity in Saccharomyces cerevisiae because of calorie restriction has been linked to enhanced mitochondrial respiratory activity. Here we have further investigated how mitochondrial respiration affects yeast life span. We found that calorie restriction by growth in low glucose increased respiration but decreased mitochondrial reactive oxygen species production relative ...
Henry Joanna R - - 2004
Structural changes in the tracheal system during development have the potential to allow insects to compensate for varying oxygen availability. Despite possible compensation, oxygen level during development may also affect insect body size. We investigated how atmospheric oxygen level affects the dimensions of the main dorsal tracheae (DT) and masses ...
Cringle Stephen J - - 2004
PURPOSE: To determine the ability of the retina and choroid in the avascular region of the rabbit retina to regulate intraretinal oxygen levels during periods of acute systemic hyperoxia. METHODS: Oxygen-sensitive microelectrodes were used to measure oxygen tension as a function of depth through the retina and choroid in anesthetized ...
Fujio M - - 2004
Equilibrium constants are reported for the ionization of benzylic alcohols to carbocations stabilized by cyclic or acyclic o-alkyl or o-oxygen substituents. The measurements were stimulated by the observation of small or inverse effects of replacement of an o-CH2 group by O or S in the cyclopentyl ring of indanol (kO/kCH2 ...
Bhambhani Yagesh N - - 2004
During the last decade, NIRS has been used extensively to evaluate the changes in muscle oxygenation and blood volume during a variety of exercise modes. The important findings from this research are as follows: (a) There is a strong correlation between the lactate (ventilatory) threshold during incremental cycle exercise and ...
Widory David - - 2004
Both oxygen and nitrogen isotope compositions (delta18O and delta15N) of exhaled air from 10 individuals were measured. Results show linear relations between isotope variation and the fraction of O2 used during the respiration process. The isotopic influence of physiological parameters such as smoking habits, age, haemoglobin count, oxygen fixation rate ...
Sumitani Makoto - - 2004
An organic/inorganic hybrid compound consisting of methylene blue, a cationic surfactant and a reductant intercalated into saponite was found to serve as an oxygen indicator that changes color in the presence of oxygen. A mixture of a blue colored dye, methylene blue, a reductant in the form of ascorbic acid ...
Hanl Lars - - 2005
The effect of decreasing oxygen feed rates on the growth and metabolism of Torulaspora delbrueckii and Saccharomyces cerevisiae in chemostat cultures was investigated. The biosynthetic oxygen requirement, i.e. the minimum specific oxygen consumption rate required for steady-state growth at a dilution rate of 0.10 h(-1), of T. delbrueckii was quantified ...
McNulty Richard - - 2004
Opacification of the lens nucleus is a major cause of blindness and is thought to result from oxidation of key cellular components. Thus, long-term preservation of lens clarity may depend on the maintenance of hypoxia in the lens nucleus. We mapped the distribution of dissolved oxygen within isolated bovine lenses ...
Aydin Atakan - - 2004
OBJECTIVE: Ingestion of button battery, if lodges in esophagus, causes mucosal destruction in esophagus and may damage surrounding tissues due to electrochemical reactions which may lead to esophagus perforation, tracheosefageal fistula and other serious problems. We designed an experimental study to test the effect of hyperbaric oxygen therapy on battery ...
van Dongen Joost T - - 2004
We studied the influence of the internal oxygen concentration in seeds of wheat (Triticum aestivum) on storage metabolism and its relation to phloem import of nutrients. Wheat seeds that were developing at ambient oxygen (21%) were found to be hypoxic (2.1%). Altering the oxygen supply by decreasing or increasing the ...
Secomb Timothy W - - 2004
PURPOSE: To simulate effects of reduced oxygen consumption combined with hyperoxic gas breathing on tumor oxygenation, and to test for synergistic effects. METHODS AND MATERIALS: Diffusive oxygen transport was simulated for a small region of tumor containing a three-dimensional network of microvessels whose geometry was derived from in vivo observations. ...
Shibuya Ken-Ichi - - 2004
This study examined cerebral deoxygenation during intermittent supramaximal exercise in six healthy male subjects (age: 27.2 +/- 0.6 years (mean +/- S.E.). The subjects performed seven times exercise at an intensity corresponding to 150% of maximal oxygen uptake (VO2max) on cycle ergometer (30 s exercise/15 s rest). Cerebral oxygenation was ...
DeMeo Dawn L - - 2004
We investigated the association between fine particulate air pollution and oxygen saturation as measured with a peripheral oxygen saturation monitor during a 12-week repeated-measures study of 28 older Boston residents. Oxygen saturation and air pollution particulates with a mean diameter less than or equal to 2.5 microm were measured continuously ...
Kimura Kazunori - - 2004
BACKGROUND: Intracavernosal oxygen tension varies greatly in the process of erection. Blood extracted from the human penis demonstrates an increase from approximately 30 mmHg Po(2) in the flaccid state to 100 mmHg in the erect state of the penis. In the present study, using these levels as a guide, we ...
Li Jia - - 2004
OBJECTIVE: We sought to assess the effects of insulin-like growth factor 1 on the balance between systemic oxygen consumption and oxygen delivery after cardiopulmonary bypass in piglets. METHODS: Twelve piglets weighing 4.5 to 8.3 kg undergoing hypothermic (28 degrees C) cardiopulmonary bypass for 70 to 120 minutes with 40 minutes ...
Kaya Takatoshi - - 2004
The metabolic activity of E. coli cells embedded in collagen gel microstructures in a cone-shaped well and in a cylindrical micropore was investigated using scanning electrochemical microscopy (SECM), based on the oxygen consumption rate and the conversion rate from ferrocyanide to ferricyanide. The analysis of the concentration profiles for oxygen ...
Radstrom M - - 2004
BACKGROUND AND OBJECTIVE: The kneeling prone position is often used for low back surgery in order to decrease intraoperative bleeding and increase the surgical exposure of the vertebral canal. The aim of this study was to assess effects of the kneeling prone position on respiratory gas exchange focusing on oxygen ...
Kalliokoski Kari K - - 2004
Capillary transit time and its heterogeneity have a marked impact on oxygen extraction in different tissues. Animal studies have shown that exercise shortens capillary transit time but the effects on capillary transit time heterogeneity have been controversial. We investigated whether exercise changes muscle blood transit time heterogeneity in humans in ...
Shibuya Ken-ichi - - 2004
The purpose of this study was to determine whether the onset kinetics of muscle oxygenation in localized working muscle (mOxy) was affected by differences in exercise intensity. Five healthy male subjects exercised for 6 min at 125 W, 150 W, and 175 W, and 1 min at 300 W on ...
Kolb Jon C - - 2004
Validation of pulse oximetry in commercially available normobaric hypoxic chambers (NHC) has not been previously reported. The present study examined the validity of pulse oximetry (SpO2) against direct measurements of arterial oxygen saturation (SaO2) via co-oximetry (AVOXimeter 4000) in 13 young adults age 21.3 +/- 0.6 years. Over a period ...
Staab A - - 2004
Chinese hamster V79-379A spheroids 200 +/- 30 microm (+/- SD) in diameter were irradiated in agitated medium in different oxygen atmospheres with (1) 227 MeV/nucleon (12)C(+6) ions (plateau region) to model tissue in the entrance channel during therapy, (2) carbon ions in the extended Bragg peak modeling tissue in the ...
Cong Yan-qing - - 2004
A novel in-situ electrochemical oxidation method was applied to the degradation of wastewater containing chlorophenol. Under oxygen sparging, the strong oxidant, hydrogen dioxide, could be in-situ generated through the reduction of oxygen on the surface of the cathode. The removal rate of chlorophenol could be increased 149% when oxygen was ...
Bliss Peter L - - 2004
BACKGROUND: Demand oxygen delivery systems (DODS) allot oxygen by interrupting the oxygen flow during exhalation, when it would mostly be wasted. Because DODS conserve oxygen by various methods, there are important performance differences between DODS. We studied certain performance factors that have not previously been carefully examined. METHODS: A bench ...
Agu Obi - - 2004
Despite the established role of compression as the basis for nonoperative treatment of chronic venous insufficiency (CVI), its mechanism of action remains unclear. Near-infrared spectroscopy (NIRS) provides continuous noninvasive monitoring of changes in tissue oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb). We applied NIRS to evaluate the effect of graded stockings on ...
Rosenfeld Eric - - 2004
Under anaerobiosis, the mitochondrion of Saccharomyces cerevisiae is restricted to unstructured promitochondria. These promitochondria provide unknown metabolic functions that are required for growth. Since high glucose concentrations are mainly fermented by S. cerevisiae during stationary phase (due to nitrogen starvation), an optimized promitochondria isolation procedure was investigated. Firstly, the unusual ...
Ghosh Asok Kumar - - 2004
aerobic to anaerobic transition intensity is one of the most significant physiological variable in endurance sports. Scientists have explained the term in various ways, like, Lactate Threshold, Ventilatory Anaerobic Threshold, Onset of Blood Lactate Accumulation, Onset of Plasma Lactate Accumulation, Heart Rate Deflection Point and Maximum Lactate Steady State. But ...
Neubauer Judith A - - 2004
This mini-review summarizes the present knowledge regarding central oxygen-chemosensitive sites with special emphasis on their function in regulating changes in cardiovascular and respiratory responses. These oxygen-chemosensitive sites are distributed throughout the brain stem from the thalamus to the medulla and may form an oxygen-chemosensitive network. The ultimate effect on respiratory ...
Whittow G C - - 2003
The oxygen consumption and respiratory frequency of Laysan Albatross eggs were measured during the different phases of pipping (paranatal period) and in hatchlings. The initial phase of pipping--penetration of the aircell of the egg by the embryonic beak--coincided with the beginning of pulmonary ventilation, the embryo rebreathing aircell gas, but ...
Cade W Todd - - 2003
OBJECTIVE: To determine the effects of human immunodeficiency virus (HIV) and highly active antiretroviral therapy (HAART) on oxygen on-kinetics in HIV-positive persons. DESIGN: Quasi-experimental cross-sectional. SETTING: Infectious disease clinic and exercise laboratory. PARTICIPANTS: Referred participants (N=39) included 13 HIV-positive participants taking HAART, 13 HIV-positive participants not taking HAART, and 13 ...
Hink Jonas - - 2003
The use of titanium during hyperbaric oxygen therapy may pose a risk of fire. A fresh titanium surface in a high oxygen atmosphere can be a source of ignition. The clinical scenario may be a patient who accidentally breaks his titanium-framed glasses during a hyperbaric oxygen treatment in a monoplace ...
Shibuya Ken-ichi - - 2003
The purpose of this study was to investigate the relationship between muscle oxygenation level at exhaustion and maximal oxygen uptake (VO2max) in an incremental cycling exercise. Nine male subjects took part in an incremental exhaustive cycling exercise, and then cuff occlusion was performed. Changes in oxy-(deltaHbO2) and deoxy-(deltaHb) hemoglobin concentrations ...
van Iterson Mat - - 2003
BACKGROUND: In this study, the hypothesis was tested that resuscitation with hemoglobin-based oxygen carriers (HBOCs) affects the oxygenation of the microcirculation differently between and within organs. To this end, we tested the influence of the volume of an HBOC on the microcirculatory oxygenation of the heart and the gut serosa ...
Vigeolas Helene - - 2003
The aim of this study was to investigate whether endogenous restrictions in oxygen supply are limiting for storage metabolism in developing oilseed rape (Brassica napus) seeds. Siliques were studied 30 d after flowering, when rapid lipid accumulation is occurring in the seeds. (a). By using microsensors, oxygen concentrations were measured ...
Sen Chandan K - - 2003
The orthodox view has been that reactive oxygen species are primarily damaging to cells. There is general agreement that while high (3%) doses of H(2)O(2) may serve as a clinical disinfectant, its overall effect on healing is not positive. Current work shows that at very low concentrations, reactive oxygen species ...
Miura Hajime - - 2004
This study tested whether regional differences in oxygenation status could result from differences in muscle fiber architecture. Architectural properties, oxygen supply, and consumption in the medial head of the gastrocnemius muscle (GM) were determined in vivo in six men using B-mode ultrasound and functional near infrared (NIR) imaging devices. Fascicle ...
Tsukada Kosuke - - 2003
A catheter-type optical oxygen sensor based on phosphorescence lifetime was developed for medical and animal experimental use. Since the sensor probe should have biocompatibility and high oxygen permeability in vivo, we focused attention on acceptable polymer materials for contact lenses as the substrates of probes. Pd-porphyrin was doped in silicone-based ...
Lee C G - - 2003
The present study measured the excess post-exercise oxygen cost (EPOC) following tests at critical swimming speed (Ucrit) in three stocks of adult, wild, Pacific salmon (Oncorhynchus sp.) and used EPOC to estimate the time required to return to their routine level of oxygen consumption (recovery time) and the total oxygen ...
Christopher Kent L - - 2003
Over the past 20 years a variety of transtracheal catheters have been developed for long-term oxygen therapy. A modified Seldinger technique has been the standard in the past, but a more recent procedure for surgical creation of the tracheocutaneous tract presents a number of potential advantages. TTO should be administered ...
Jensen Pernille N - - 2003
Storage of nuts at a high oxygen concentration results in rancid nuts whereas storage at a low oxygen concentration results in fine-tasting nuts. During a 13 month experiment, packaging of walnuts with an oxygen absorber was compared to packaging in nitrogen or atmospheric air. At the same time, the effects ...
Mizuno Masaki - - 2003
This investigation evaluated regional differences in blood flow and oxygen consumption and their relationship in exercised muscle during recovery from exhaustive exercise. Five healthy men performed exhaustive one-legged cycling exercise. Positron emission tomography was used to measure blood flow, oxygen uptake, and oxygen extraction in the quadriceps femoris muscle before ...
Zavorsky Gerald S - - 2003
The aim of this study was to determine the effect of acute plasma volume expansion on arterial blood-gas status during 6.5 min strenuous cycling exercise comparing six athletes with and six athletes without exercise-induced arterial hypoxaemia (EIAH). We hypothesized that plasma volume expansion could improve arterial oxygen pressure in a ...
Brunelli Alessandro - - 2003
OBJECTIVE: To identify predictors of postoperative exercise oxygen desaturation (EOD) in patients submitted to lobectomy or pneumonectomy for lung carcinoma. PATIENTS AND METHODS: A consecutive series of 227 patients with non-small cell lung cancer submitted to lobectomy or pneumonectomy from January 2000 through October 2002 were prospectively analyzed. Maximal stair-climbing ...
Zhao Weili - - 2003
A Raman scattering system was used to measure the O2 (a1delta) yield end the chlorine utilization in a singlet oxygen generator of chemical oxygen iodine laser with nitrogen diluent. We present the results from the tests that conducted on a 0.1-mol/s jet-type singlet oxygen-iodine generator. On the basis of the ...
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