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Results 451 - 500 of 995
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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 ...
Van der Linden P - - 1998
We have explored systemic and regional tolerance to haemodilution during anaesthesia with two different synthetic colloids. Eighteen dogs undergoing mechanical ventilation during anaesthesia with ketamine were submitted to progressive normovolaemic haemodilution with either gelatin (GEL; n = 9) or hydroxyethylstarch (HES; n = 9) administered on a 1:1 ratio. Systemic ...
Wolff K D KD Department of Maxillofacial Plastic Surgery, Benjamin Franklin Medical Center, and Institute of Mathematical Statistics, Epidemiology and Informatics, Free University of Berlin, - - 1998
Microsurgical skin flaps raised from various body regions show differences in vascular architecture, cutaneous capillary density, and skin perfusion. Therefore, it can be expected that oxygenation of the skin is different at the various free flap donor sites. To determine the cutaneous oxygen supply, intracapillary hemoglobin oxygenation was measured on ...
Giffin D M - - 1998
OBJECTIVES: Peritoneal ventilation (PV) can greatly increase PaO2 in hypoxemic rabbits. We tested the hypothesis that the peritoneum can provide a gas exchange surface for oxygen uptake in larger animals that, like humans, have a smaller relative peritoneal surface area and corresponding blood flow. DESIGN: Prospective, randomized, controlled animal study. ...
Everett S A - - 1998
The factors influencing the kinetics of the oxygen-sensitive reduction of indolequinones, including those bearing leaving groups in the (indol-3-yl)methyl position, have been studied. The hydroquinones derived from some representative indolequinones were found to autoxidize slowly in oxygenated solution at rates (effective rate constant with O2 approximately 40-300 M-1 s-1) that ...
Iida T - - 1998
OBJECTIVE: Despite the increased cardiac output and oxygen delivery, an impaired oxygen uptake has been noted in patients with cirrhosis. We recently observed that endoscopic variceal ligation decreased the cardiac output due to a reduction in the cardiac preload. It is thus possible that a variceal ligation decreases the oxygen ...
Georgakoudi I - - 1998
We present experimental evidence that demonstrates directly how the subcellular localization and redistribution of two nile blue derivatives, 5-ethylamino-9-diethyl-aminobenzo[a]phenothiazinium chloride (EtNBS) and 5-ethylamino-9-diethyl-aminobenzo[a]phenoselenazinium chloride (EtNBSe), affect oxygen consumption during irradiation of sensitized multicell EMT6 spheroids. Specifically, two well-defined phases of oxygen consumption are observed during treatment, with the onset of ...
Laycock S K - - 1998
Inhibition of NO synthesis has recently been shown to increase oxygen extraction in vivo, and NO has been proposed to play a significant role in the regulation of oxygen consumption by both skeletal and cardiac muscle in vivo and in vitro. It was our aim to determine whether NO also ...
Nollert G - - 1998
Neuropsychological and neurological deficits are still major causes of mortality and morbidity after cardiac operations and are thought to be caused by embolism and cerebral hypoxia. Near-infrared spectrophotometry (NIRS) is a promising method for non-invasive monitoring of cerebral oxygenation and hemodynamics. Different devices provide information on changes of oxygenated (HbO2) ...
Daga S R - - 1998
Oxygen saturation was studied in eight newborn babies, seven preterm and one term, with and without caressing by the mother while receiving gavage feeds. The babies were stable with regard to cardiorespiratory and neurological status. Four babies were still receiving head-box oxygen. The oxygen saturation levels were similar before feeds. ...
Liam B L - - 1998
OBJECTIVE: The purpose of this study was to determine the minimum hematocrit value that can support whole body oxygen consumption during normothermic cardiopulmonary bypass. The effect of hemodilution on peripheral resistance, whole body oxygen delivery, and oxygen consumption was determined over a range of hematocrit values. METHODS: Measurements were obtained ...
Arteel G E - - 1998
2-Nitroimidazoles, such as pimonidazole, are reduced in cells with low oxygen tension and are, therefore, used as hypoxia markers. However, the effect of the pyridine nucleotide redox state on pimonidazole reduction is not known. Therefore, livers from fed or fasted rats were perfused with oxygen-saturated buffer containing pimonidazole (400 microM) ...
Evans E N - - 1998
Patients undergoing bronchoscopy are usually monitored with pulse oximetry to measure arterial oxygen saturation, but this can fail to detect hypoventilation, particularly if added inspired oxygen is used. Transcutaneous oxygen and carbon dioxide tensions can be measured; the later reflecting respiratory drive. We compared transcutaneous PO2 and PCO2 values with ...
Stanek A - - 1998
Respiratory infection is a major cause of morbidity after general anaesthesia. Impairment of respiratory ciliary beat frequency (CBF) by different stress factors causes a decrease in mucus transport rate (MTR). We have tested the effect of different concentrations of oxygen on CBF of human respiratory epithelium in a prospective, randomized, ...
Burness G P - - 1998
Basal metabolic rate is one of the most widely measured physiological traits. Previous studies on lab mice and field-caught lizards suggest that individuals with relatively high basal metabolic rates or standard metabolic rates have relatively large masses of metabolically active tissues (e.g., heart, kidney, liver). As these are energetically expensive ...
Weg J G - - 1998
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), ...
Gnaiger E - - 1998
The oxygen affinity of the enzyme system involved in mitochondrial respiration indicates, in relation to intracellular oxygen levels and interpreted with the aid of flux control analysis, a significant role of oxygen supply in limiting maximum exercise. This implies that the flux control coefficient of mitochondria is not excessively high, ...
Vacchiano C A - - 1998
Oxygen exposure for a sufficient duration at high partial pressure results in pulmonary edema in humans and animals. Although the specific mediators of oxygen toxicity are unknown, evidence suggests that oxygen-based radicals such as superoxide anion (O2.) are increased in the lungs in the presence of hyperoxia and contribute to ...
Waldau T - - 1998
Oxygen supply systems may be divided into constant and variable performance systems. As the variable performance systems are widely used, it is relevant to investigate the variation in performance between devices and the influence of oxygen supply on the inspired oxygen fraction. Data were collected from 10 healthy volunteers during ...
Fajac I - - 1998
Sampling arterialized earlobe blood is thought to be easier and less painful than direct arterial puncture, and to allow measurement of blood gas values during exercise without the need to insert an arterial cannula. However, arterialized earlobe oxygen tension (PO2) often underestimates arterial PO2 at rest, and is not fully ...
Thomas Klasson K - - 1998
Two aerobic microorganisms,Saccharomycopsis lipolytica andBrevibacterium lactofermentum, have been used in a study of mass transfer and oxygen uptake from a global perspective, using a closed gas system. Oxygen concentrations in the gas and liquid were followed using oxygen electrodes; the results allowed for easy calculation of in situ oxygen transport. ...
Scheller D - - 1998
The present study was performed in order to determine the oxygen consumption of a rat brain perfused with an artificial oxygen carrier. Measurements were performed prior to and 2 or 30 min after an ischemic period of 5 min. In addition, the energy-related metabolites were determined. Basal oxygen consumption and ...
Schaffranietz L - - 1998
Since the concept of hyperventilation on neurosurgical and neurotraumatological patients has been contested, our analysis was aimed at its scrutiny on the basis of easily accessible parameters of perisurgical monitoring. Furthermore, the influence of an improved oxygen supply was tested on hyperventilationally induced cerebral changes and to what extent recommendations ...
Webster A L - - 1998
The purpose of this study was to determine the effects of a 1-h exposure to 2.0 atm abs (202.6 kPa) and 100% oxygen on subsequent maximal O2 consumption (VO2max), ventilation threshold (VT), lactate threshold (LT), and muscle oxygenation (%Mox) during incremental exercise to maximum on a cycle ergometer. Two baseline ...
Wells J M - - 1998
Long hyperbaric exposures of humans, at pressures in excess of 2.5 atmospheres, require that the oxygen concentration of the breathing gas be maintained at levels less than atmospheric air, in order to prevent pulmonary oxygen toxicity. Carbon dioxide produced by humans must be removed from the breathing gas of closed ...
Ditadi A S - - 1997
The present study deals with a species of enteropneust, Glossobalanus crozieri, focusing on two aspects of its respiration: a) oxygen consumption and body mass, and b) the influence of environmental oxygen tension on the respiratory rate. Preliminarily, the body water content was shown to be 85% of the whole body ...
Cohen-Solal A - - 1997
OBJECTIVE: To evaluate the ratio of peak oxygen consumption to peak heart rate (peak oxygen pulse) as a predictor of long term prognosis in chronic heart failure. PATIENTS AND SETTING: 178 consecutive heart failure patients recruited to the cardiology department of a tertiary referral centre between 1986 and 1993. DESIGN: ...
Aneman A - - 1997
Sympathetic and angiotensinergic activation reduce splanchnic oxygen delivery during hypovolemia, which may lead to failure of the intestinal mucosal barrier and eventually multiple organ dysfunction. This study integrates sympathetic and angiotensinergic responses with splanchnic hemodynamics and duodenal mucosal function during hypovolemia and evaluates pharmacologic blockade of either system to ameliorate ...
Thorn J J - - 1997
PURPOSE: This study measured the effect of hyperbaric oxygen (HBO) treatment on transmucosal oxygen tension in irradiated human oral mucosa. PATIENTS AND METHODS: Ten patients received 30 dives of HBO as part of their treatment for mandibular osteoradionecrosis. A noninvasive, nonheated oxygen electrode was used to measure the tissue surface ...
Ohno T - - 1997
Mixed venous oxygen saturation (SvO2) and physical activity (PhyAc) are practical candidates as parameters of total artificial heart (TAH) control because SvO2 can be measured through a transparent blood pump housing with infrared rays and PhyAc can be calculated from signals of an accelerometer used for rate response pacemakers. Although ...
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