Search Results
Results 401 - 450 of 973
< 4 5 6 7 8 9 10 11 12 13 14 >
Doherty M - - 2000
The aim of this study was to determine the reproducibility of the maximal accumulated oxygen deficit and the associated exercise time to exhaustion during short-distance running. Fifteen well-trained males (mean +/- s: VO2max = 58.0+/-4.6 ml x kg(-1) x min(-1)) performed the maximum accumulated oxygen deficit test at an exercise ...
Hedenstierna G - - 2000
Atelectasis is a frequent finding in paralysed and mechanically ventilated patients. Atelectasis, causing shunt, impairs oxygenation and could contribute to postoperative pulmonary complications. Pre-oxygenation used during anaesthesia induction causes atelectasis. A lowering of oxygen fraction from 100% to 80% does not shorten the safety time of apnoea period, particularly useful ...
Bangsbo J - - 2000
This review presents data on human muscle oxygen consumption in the initial phase of exercise as well as on muscle maximal oxygen uptake. It also discusses mechanistic limiting factors related to oxygen utilization at the onset of exercise and of maximal aerobic power of skeletal muscle. Direct measurements of oxygen ...
Kondo M - - 2000
Reactive oxygen species are regarded as a possible cause of many diseases. However, there are few reports offering in vivo and in situ proof of the direct involvement of reactive oxygen species in the pathogenesis of disease. In the present study, the luciferin derivative 2-methyl-6-[4-methoxyphenyl]-3,7-dihydroimidazo [1,2-alpha] pyrazin-3-one (MCLA) was used ...
Bae S Y - - 2000
The two purposes of the present study were 1) to determine the oxygen consumption in working skeletal muscle from the oxygenation measured by near-infrared continuous-wave spectroscopy (NIRcws) with the arterial occlusion method during the resting condition, INT(VT), and INT(MAX) and 2) to examine whether the decline rate of oxygenation is ...
Li J - - 2000
OBJECTIVE: We sought to assess oxygen consumption and its determinants in children shortly after undergoing cardiopulmonary bypass operations. METHODS: Twenty children, aged 2 months to 15 years (median, 3.75 years), undergoing hypothermic cardiopulmonary bypass operations were studied during the first 4 hours after arrival in the intensive care unit. Central ...
MacIntyre N R - - 2000
Lung disease affects exercise performance through a number of mechanisms, including hypoxemia, abnormal ventilatory mechanics, abnormal ventilatory muscles, abnormal ventilatory patterns, abnormal right heart function and subjective dyspnea. Supplemental oxygen improves hypoxemia and thus improves exercise impairment resulting from hypoxemia-related reductions in oxygen delivery. Supplemental oxygen also reduces exercise ventilation. ...
Stefanova D - - 2000
Short (up to 60 s) supramaximal (about 400 W on the average) exercise is accompanied by specific biochemical processes in the working muscles and by a general increase in energy metabolism. Outwardly, this is manifested by an excess post-exercise oxygen consumption (EPOC). Since its actual measurement is time consuming and ...
Burioka N - - 2000
It is well known that conventional bubbling humidifiers are capable of producing micro-aerosols contaminated with bacteria. We developed a unique humidifier, named a membrane humidifier, that does not require an external water supply. This new system obtains moisture from room air. We investigated the clinical and in vitro evaluation of ...
Chown S L - - 2000
It has been suggested that discontinuous gas exchange cycles (DGCs) in insects evolved in response to hypoxic and/or hypercapnic environments, and that the flutter phase of the DGC is predominantly diffusive. We tested these hypotheses by examining the rate of CO(2) release at a declining series of oxygen partial pressures ...
Criner G J - - 2000
In general, based on the above studies of the effects of supplemental oxygen on reducing mortality and improving sleep and exercise function in certain patient groups, patients whose disease is stable on a full medical regimen with PaO2 < or = 55 mm Hg (SaO2 < or = 88%) should ...
Stücker M - - 2000
In skin lesions of chronic venous incompetence (CVI) transcutaneous oxygen pressure (tcpO(2)) at the ankle is often reduced. However, in some CVI patients the tcpO(2) during suprasystolic occlusion remains significantly higher than in healthy subjects. The aim of the present study was to investigate which kind of CVI patients develop ...
Russell S D - - 1999
Recent uncontrolled studies have suggested improved maximal exercise capacity and decreased exercise ventilation in heart failure after administration of increased inspired oxygen concentrations. To study the responses further, 16 patients performed staged, symptom-limited cycle ergometry with humidified 21% and 60% inspired oxygen concentrations using a randomized, double-blind, crossover study design. ...
Scott C B - - 1999
Above the lactate/ventilatory threshold, prolonged steady-state exercise produces a secondary rise in oxygen uptake, the slow oxygen component. The slow oxygen component 'represents an additional energetic requirement' above steady state; however, a lack of consensus on how to measure anaerobic energy expenditure makes it difficult to ascertain how or if ...
Malley K S - - 1999
Fire departments have replaced traditional uniforms with modern, more thermal protective gear. Although the new uniforms afford superior burn protection, they may reduce work time. Our purpose was to determine if exercise time was (1) reduced by wearing the modern versus traditional uniform, and (2) increased by a design change ...
di Prampero P E - - 1999
This paper discusses under an energetic perspective the recent and older evidence supporting the classical notion that the 'oxygen debt', as originally defined by Margaria et al. (1933) [Am. J. Physiol. 106, 689-714], consists of two major components: the alactic oxygen debt, with a half-time of the order of 30 ...
Colier W N WN Department of Physiology (237), Faculty of Medical Sciences, University of Nijmegen, P.O. Box 9101, NL-6500 HB Nijmegen, The Netherlands. - - 1999
Near-infrared spectroscopy (NIRS) was used to assess human motor-cortex oxygenation changes in response to cyclic coupled movements of hand and foot. Using a highly sensitive NIRS instrument, we showed that it was possible to detect reproducible oxygenation patterns using single cycles (20 s) of easy and difficult association tasks. No ...
McCully K K - - 1999
The purpose of this study was to determine if chronic fatigue syndrome (CFS) is associated with reduced oxygen delivery to muscles. Patients with CFS according to CDC (Center for Disease Control) criteria (n=20) were compared with normal sedentary subjects (n=12). Muscle oxygen delivery was measured as the rate of post-exercise ...
Primosch R E - - 1999
PURPOSE: The purpose of this study was to determine the influence of 40% nitrous oxide/60% oxygen inhalation with scavenging on the behavioral and physiological parameters during routine pediatric dental procedures. METHODS: Twenty-two subjects, aged 60-116 months, were randomized into a double blind, cross-over study design and administered alternately either 40% ...
Mukherjee J - - 1999
On-line monitoring of NAD(P)H fluorescence and 2D fluorescence spectroscopy was performed with Enterobacter aerogenes, a bacterium sensitive to oxygen availability. The organism was grown in a reactor under low and high dissolved oxygen concentrations and circulated through a bypass attached to the reactor. Under low dissolved oxygen concentration in the ...
Nakamura M - - 1999
We developed a control of the total artificial heart (TAH) using mixed venous oxygen saturation (SvO2). With this method, the TAH output was controlled by automatically adjusting drive parameters in response to changes in measured SvO2. The feasibility and validity of this method were evaluated in a series of treadmill ...
Takeda T - - 1999
We determined aerial and aquatic oxygen uptake rates (&Mdot;o(2)) of Periophthalmodon schlosseri at rest and after exhaustive exercise at 30 degrees C. Resting &Mdot;o(2) in air (3.16 +/- 0.10 [SE] &mgr;mol/g/hr) was significantly higher than that in air saturated water (2.41 +/- 0.06 &mgr;mol/g/hr). When the fish was placed in ...
Neri M - - 1999
As liquid oxygen represents a relevant burden on healthcare systems, different methods have been developed to reduce oxygen consumption, including economizers. The aims of the study were: 1) to evaluate the efficacy of an economizer device (Companion 5 Oxygen Saver) in a significant sample of patients, and 2) to perform ...
Barja G - - 1999
Studies in heart and nonsynaptic brain mitochondria from two mammals and three birds show that complex I generates oxygen radicals in heart and nonsynaptic brain mitochondria in States 4 and 3, whereas complex III does it only in heart mitochondria and only in State 4. The increase in oxygen consumption ...
Veasey D A - - 1999
This study measured oxygen concentrations of air within totally encapsulating chemical-protective (TECP) suits during simulated hazardous materials emergency response operations. This was done to allow assessment of the suitability of use of air within TECP suits as an emergency air supply during escapes from contaminated areas following loss of primary ...
Zhao G - - 1999
In addition to regulating vascular tone, there is increasing evidence for the involvement of NO in the modulation of oxygen consumption. Our in-vitro studies indicated that exogenous and endogenous NO reduces the consumption of oxygen in isolated canine skeletal and cardiac muscle, which is probably related to its direct effect ...
Gallez B - - 1999
Using the broadening of the electron paramagentic resonance (EPR) linewidth of paramagnetic particles by oxygen, it is possible to make measurements of the partial pressure of oxygen in vivo. While the results obtained so far with EPR oximetry are very encouraging, several paramagnetic materials may lose their responsiveness to oxygen ...
Wilkes A R - - 1999
A breathing system filter can remain connected to a laryngeal mask airway during recovery from anaesthesia. The Luer-lock monitoring port on the filter could be used for the delivery of supplementary oxygen. The efficacy of this technique was assessed in vitro by comparing the performance of two filters with four ...
Moriyama S - - 1999
We hypothesized that patients who have undergone hypothermic cardiopulmonary bypass may have abnormal oxygen metabolism after cardiac surgery because of oxygen debts that occurred during cardiopulmonary bypass. A prospective study was designed to determine oxygen consumption and carbon dioxide production using an indirect calorimeter in 45 adult patients who underwent ...
Carraway M S - - 1999
That hyperoxia induces "a profound modification in the metabolism of tissues" is an old observation. The mechanisms by which the physiologic, pathologic, and biomechanical perturbations caused by oxygen relate to the in vivo manifestations of oxygen toxicity, however, have not been explained fully. This article reviews cellular mechanisms of toxicity, ...
Nishiyasu T - - 1999
During the application of a wide range of graded lower body pressures (LBP) (-50 to 50 mmHg), we examined how (1) the tissue oxygenation in the lower and upper parts of the body changes at rest, and (2) how tissue oxygenation changes in the lower extremities during dynamical leg exercise. ...
Capellier G - - 1999
Normobaric oxygen toxicity is well described in all animal species. However susceptibility to oxygen exposure is highly variable according to age, species and strains. Similarly in humans, prolonged high oxygen exposure is reported to induce cough, shortness of breath, decrease vital capacity and increase alveolo-capillary permeability. The toxic FIO2 threshold ...
Piantadosi C A - - 1999
Carbon monoxide (CO) poisoning is a common occurrence in today's society. Most such poisonings are a direct consequence of inhaling the toxic byproducts of combustion. Exposure to toxic amounts of CO occurs most often during inhalation of automobile exhaust or smoke resulting either from faulty heating systems or industrial accidents. ...
Belardinelli R - - 1999
Patients with chronic heart failure (HF) have a reduced skeletal muscle blood flow which can in part explain reduced exercise tolerance and increased ventilation. All the techniques commonly employed to measure skeletal muscle blood flow have limitations that reduce their accuracy and clinical application. Near infrared spectroscopy (NIRS) is a ...
Yoshitake A - - 1999
OBJECTIVE: To investigate preoperative clinical conditions and/or intraoperative physiologic variables related to jugular venous oxygen saturation (SjO2) during cardiopulmonary bypass (CPB). DESIGN: Prospective study. SETTING: General hospital, single institution. PARTICIPANTS: One hundred forty patients (52 women, 88 men) who underwent coronary artery bypass grafting. MEASUREMENTS AND MAIN RESULTS: The authors ...
Nakamura M - - 1999
For physiological control of a total artificial heart (TAH), applying mixed venous oxygen saturation (SVO2) as a parameter for TAH control is a promising approach regarding sensitivity to the recipient's oxygen demand and the practical possibility of continuous monitoring using near infrared rays through transparent blood pump housings. To develop ...
Schmitz A - - 1999
First instars of Carausius morosus provide a good model for morphometric evaluation of the diffusing capacity between the tracheal system and hemolymph: air sacs are lacking, tracheoles do not penetrate the organs and muscles, and entire animals can be evaluated electron microscopically without subsampling. The tracheal volume makes up 1.3% ...
Reybrouck T - - 1999
STUDY OBJECTIVES: To analyze gender differences in the oxygen transport system at peak exercise with particular emphasis on the difference in systemic arteriovenous oxygen extraction and in mixed venous oxygen saturation. PATIENTS AND METHODS: Cardiopulmonary graded exercise testing and hemodynamic assessment were performed on a cycle ergometer in 64 hypertensive ...
Chen J Y - - 1999
The influence of oxygen on alkaline lipase production by Acinetobacter radioresistens was studied under two operating modes: controlled dissolved oxygen (DO) concentration and controlled aeration rate. Compared with cell growth, the lipase production depended more extensively on oxygen. The intrinsic factor determining cell growth and lipase production was oxygen transfer ...
Keller R R - - 1999
Since the early beginnings of long-term oxygen therapy, by means of cylinders of compressed oxygen and their subsequent replacement with oxygen concentrators, most technical advances have been steadily focused on improving the facilities for continuous ambulatory oxygen therapy. Largely for this purpose, two different systems have been developed. 1) Oxygen ...
Abe K - - 1999
We evaluated the effect of coenzyme Q10 supplementation to two patients with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) by using noninvasive tissue oximetry with near-infrared spectra of hemoglobin from the quadriceps muscle during bicycle ergometer exercise. Patients showed distinct oxygen consumption patterns reflecting the defect in oxidative ...
Crago M S - - 1999
The hemodynamic and metabolic effects of diaspirin crosslinked hemoglobin (DCLHb) were investigated using graded treadmill exercise in swine (n = 5/group). Swine received DCLHb (10% solution, 5 ml/kg) or oncotically-matched human serum albumin (HSA, 5ml/kg). Baseline metabolic and hemodynamic data were similar. In both groups exercise increased hemodynamic parameters. Exercise ...
Farmer C G - - 1999
Vertebrate lungs have long been thought to have evolved in fishes largely as an adaptation for life in hypoxic water. This view overlooks the possibility that lungs may have functioned to supply the heart with oxygen and may continue to serve this function in extant fishes. The myocardium of most ...
Jurisevic M A - - 1999
Rates of oxygen consumption during begging behaviour in nestlings of seven species and distress call behaviour in adults of eight species of Australian birds were measured. A transparent mask coupled to an open-flow respirometry system was used, and calling was elicited by the presentation of food or by the perceived ...
Van Beekvelt M C - - 1999
Five patients with chronic progressive external ophthalmoplegia (CPEO) and 27 healthy controls were examined by near-infrared spectroscopy (NIRS) for the non-invasive and direct quantitative measurement of muscle oxygen consumption during rest as well as during static isometric handgrip exercise at 10% of their maximum voluntary contraction. In patients with CPEO, ...
Ehleben W - - 1998
Light absorption photometry of HepG2 cells treated with phenobarbital for enhancing the content of cytochrome P-450 and the synthesis of erythropoietin revealed an influence on all cytochromes detectable in the wavelength range between 400 and 620 nm. No correlation was found between specific changes of cytochrome P-450 absorption and increased ...
Gilljam T - - 1998
AIMS: To assess the determinants of exercise capacity and exercise oxygenation after atrial redirection for complete transposition. METHODS AND RESULTS: At graded bicycle ergometry, including respiratory and arterial blood gas analyses, intra-arterial blood pressure recording, and cardiac output determination (dye-dilution technique), we tested 17 post-Mustard/Senning patients, 8.9-22.0 years old (mean ...
Tirdel G B - - 1998
BACKGROUND: Cardiopulmonary exercise (CPEx) studies of lung transplant (LTx) recipients have found low maximum oxygen consumptions because of an as yet unexplained mechanism. Although it is likely that a significant problem resides within the mitochondria, this study determines whether a defect in oxygen uptake or utilization is present. METHODS: Six ...
Kimura T - - 1998
Neo Red Cell (NRC), which is the liposome encapsulated hemolysate, has been developed as an artificial oxygen carrier. Oxygen carrying capacity and oxygen supply rate of NRC were estimated by continuous measurement of dissolved oxygen concentration in a spinner vessel. Oxygen carrying capacity of the medium was risen by adding ...
Garry D J - - 1998
Myoglobin, an intracellular haemoprotein expressed in the heart and oxidative skeletal myofibres of vertebrates, binds molecular oxygen and may facilitate oxygen transport from erythrocytes to mitochondria, thereby maintaining cellular respiration during periods of high physiological demand. Here we show, however, that mice without myoglobin, generated by gene-knockout technology, are fertile ...
< 4 5 6 7 8 9 10 11 12 13 14 >