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Frappell Peter B - - 2003
The platypus (Ornithorhyncus anatinus) is characterized by a rate of oxygen consumption (V(O2))that is higher than that reported for other similar sized monotremes, similar to marsupials and somewhat lower than eutherians. The platypus is also characterized by a breathing pattern, more typical of a diving mammal, with a high 'inspiratory ...
Holbrook Gabriel P - - 2003
Phosphate recycling under photorespiratory conditions was investigated using intact wheat chloroplasts from Triticum aestivum (cv. Maris dove). A decline in the optimal Pi level needed to support steady-state photosynthesis was observed (a) as the bicarbonate supply became limiting, or (b) as oxygen concentrations were increased. Further, at subsaturating CO2 and ...
Tanaka Hirofumi - - 2003
Physiological functional capacity (PFC) is defined here as the ability to perform the physical tasks of daily life and the ease with which these tasks can be performed. For the past decade, we have sought to determine the effect of primary (healthy) adult human aging on PFC and the potential ...
Andersson Johan P A - - 2004
The effect of the diving response on alveolar gas exchange was investigated in 15 subjects. During steady-state exercise (80 W) on a cycle ergometer, the subjects performed 40-s apneas in air and 40-s apneas with face immersion in cold (10 degrees C) water. Heart rate decreased and blood pressure increased ...
Homi H Mayumi - - 2003
BACKGROUND: Xenon has been shown to be neuroprotective in several models of in vitro and in vivo neuronal injury. However, its putative neuroprotective properties have not been evaluated in focal cerebral ischemia. The purpose of this study was to determine if xenon offers neuroprotection in a mouse model of middle ...
Cautero M - - 2003
We summarise recent results obtained in testing some of the algorithms utilised for estimating breath-by-breath (BB) alveolar O2 transfer (VO2A) in humans. VO2A is the difference of the O2 volume transferred at the mouth minus the alveolar O2 stores changes. These are given by the alveolar volume change at constant ...
Zhang Yan - - 2003
The physiological significance of the position and shape of the oxygen equilibrium curve (OEC) of horse hemoglobin (Hb) is considered from the viewpoint of oxygen (O2) transport efficiency and the effectiveness of the Bohr effect. In horse fetal and maternal bloods, their physiological O2 affinities are nearly optimized with respect ...
Nguyen T - - 2003
A robust algorithm for pull-calorimeters that provides a rapid response to changes in respiratory gas exchange has been implemented. Metabolic plateaus (over 20 min), such as that generated by steady treadmill exercise, can be measured accurately (< 2.0% error for an energy expenditure level of 16.7 kJ min(-1)). The time ...
di Prampero Pietro Enrico - - 2003
Theoretical best performance times (ttheor) in track running are calculated as follows. Maximal metabolic power (Emax) is a known function of maximal oxygen uptake (VO2max), of maximal anaerobic capacity (AnS) and of effort duration to exhaustion (te):Emax=f (te). Metabolic power requirement (Er) to cover the distance (d) in the performance ...
Solås A B - - 2003
OBJECTIVE: Superoxide radicals (O2-) are generated during reoxygenation following asphyxia, possibly more when higher concentrations of O2 are used during resuscitation. Superoxide dismutase (SOD) is an antioxidant enzyme, which scavenges O2-. We tested the hypothesis that a single intravenous dose of recombinant human Cu,Zn SOD (rhSOD) could influence microcirculation and ...
Ehsani Ali A - - 2003
To determine the mechanisms underlying increased aerobic power in response to exercise training in octogenarians, we studied mildly frail elderly men and women randomly assigned to an exercise group (n = 22) who participated in a training program of 6 mo of physical therapy, strength training, and walking followed by ...
Jain Preeti - - 2003
Administration of alkalinizing agents has been shown to improve performance in high intensity exercise. The present investigation was undertaken to determine whether sodium citrate ingestion enhances supramaximal endurance performance on a cycle ergometer and to assess its effect on oxygen debt incurred for the same supramaximal energy output. Ten untrained, ...
Halsey Lewis - - 2003
While optimal diving models focus on the diver's oxygen (O(2)) stores as the predominant factor influencing diving behaviour, many vertebrate species surface from a dive before these stores are exhausted and may commence another dive well after their O(2) stores have been resaturated. This study investigates the influence of hypoxia ...
Brookes Paul S - - 2003
Nitric oxide (NO.) inhibits mitochondrial respiration by binding to the binuclear heme a3/CuB center in cytochrome c oxidase. However, the significance of this reaction at physiological O2 levels (5-10 microM) and the effects of respiratory state are unknown. In this study mitochondrial respiration, absorption spectra, [O2], and [NO.] were measured ...
Sato Katsufumi - - 2003
Aquatic animals use a variety of strategies to reduce the energetic cost of locomotion. Efficient locomotion is particularly important for breath-holding divers because high levels of exercise may quickly deplete oxygen reserves, leading to the termination of a dive. We investigated the swimming behavior of eight adult Weddell seals, which ...
Jammes Yves - - 2003
We compared the changes in compound muscle mass action potential (M-wave) recorded in vastus lateralis in response to hyperbaric hyperoxia (HBO) in nine combat divers who dived daily while breathing 100% O2 or O2-enriched mixture (O2 divers) to those measured in eight recreational divers who dived occasionally using compressed air/21% ...
Stanopoulos Ioannis - - 2003
PURPOSE: To investigate possible effects of sildenafil on the cardiopulmonary responses during sexual intercourse we evaluated cardiopulmonary responses during exercise in a group of impotent patients. MATERIALS AND METHODS: The study sample included patients with erectile dysfunction who underwent a cardiopulmonary exercise test before and after the administration of 100 ...
Schindler A W - - 2003
BACKGROUND: Oxygen consumption (V*O2) is rarely measured during anaesthesia, probably because of technical difficulties. Theoretically, oxygen delivery into a closed anaesthesia circuit (V*O2-PF; PhysioFlex Draeger Medical Company, Germany) should measure V*O2. We aimed to measure V*O2-PF in vitro and in vivo. METHODS: Three sets of experiments were performed. V*O2-PF was ...
Dempsey Jerome A - - 2003
It is commonly held that the structural capacity of the normal lung is "overbuilt" and exceeds the demand for pulmonary O2 and CO2 transport in the healthy, exercising human. On the other hand, the adaptability of pulmonary system structures to habitual physical training is substantially less than are other links ...
Reybrouck Tony - - 2003
OBJECTIVE: The effect of increasing work rate was studied on the determinants of the oxygen deficit. METHODS: Exercise testing was performed on a treadmill and gas exchange was measured on a breath-by-breath basis. Eleven healthy subjects, aged 18-25 years, performed three square wave exercise tests of different intensity. Before exercise, ...
Green J A - - 2003
Heart rate (fH), abdominal temperature (T(ab)) and diving depth were measured in thirteen free-ranging breeding female macaroni penguins. Measurement of these variables allowed estimation of the mass-specific rate of oxygen consumption (V(O(2))) while diving and investigation of the physiological adjustments that might facilitate the diving behaviour observed in this species. ...
Parkes Roland - - 2002
The rate of oxygen uptake at the surface between dives was measured for four tufted ducks, Aythya fuligula, during bouts of foraging dives to a depth of 1.8 m. The ducks surfaced into a respirometer box after each dive so that the rate of oxygen uptake ((O(2))) could be measured. ...
Elliott Nicole M - - 2002
While diving, harbour seals (Phoca vitulina) manage their oxygen stores through cardiovascular adjustments, including bradycardia, a concurrent reduction in cardiac output, and peripheral vasoconstriction. At the surface, post-dive tachycardia facilitates rapid reloading of oxygen stores. Although harbour seals can tolerate >20 min of submergence, the majority of their natural dives ...
González-Alonso José - - 2002
Blood flow to contracting skeletal muscle is tightly coupled to the oxygenation state of hemoglobin. To investigate if ATP could be a signal by which the erythrocyte contributes to the regulation of skeletal muscle blood flow and oxygen (O2) delivery, we measured circulating ATP in 8 young subjects during incremental ...
Calbet J A L - - 2003
Acute hypoxia (AH) reduces maximal O2 consumption (VO2 max), but after acclimatization, and despite increases in both hemoglobin concentration and arterial O2 saturation that can normalize arterial O2 concentration ([O2]), VO2 max remains low. To determine why, seven lowlanders were studied at VO2 max (cycle ergometry) at sea level (SL), ...
Hill David W - - 2002
The purpose of this study was to compare values for maximal accumulated O2 deficit measured in running and cycling. Nine university students performed five fatiguing constant-velocity treadmill tests and five fatiguing constant-power cycle ergometer tests at intensities within the severe domain. O2 deficit was determined making the traditional assumptions that ...
Uchida Issei - - 2002
Correlations between baseline hemodynamic and oximetric variables during an invasive exercise test and an improvement in peak oxygen uptake (peak VO2) after exercise training (ET) were examined in 20 patients who participated in a cardiac rehabilitation program after acute myocardial infarction (AMI). Peak VO2 significantly increased by 23 +/- 21% ...
Frappell Peter - - 2002
Oxygen transfer during sustained maximal exercise while locomoting on a treadmill at 0.33 m s(-1) was examined in a varanid lizard Varanus mertensi at 35 degrees C. The rate of oxygen consumption (V*O2) increased with locomotion from 3.49+/-0.75 (mean +/- S.D.) to 14.0+/-4.0 ml O2 kg(-1) min(-1). Ventilation (V*E) increased, ...
Andersson Johan P A - - 2002
This study addressed the effects of apnea in air and apnea with face immersion in cold water (10 degrees C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed ...
Jensen Gabrielle - - 2002
STUDY OBJECTIVES: In patients with terminal lung disease who were exercising, we assessed whether improved arterial O2 saturation with an increased fraction of inspired oxygen (FIO2) affects cerebral oxygenation. DESIGN: Randomized, crossover. PATIENTS AND METHODS: The cerebral changes in oxyhemoglobin (DeltaHbO2) and changes in deoxyhemoglobin (DeltaHb) levels were evaluated using ...
Nielsen Henning B - - 2002
The contribution of pH to exercise-induced arterial O2 desaturation was evaluated by intravenous infusion of sodium bicarbonate (Bic, 1 M; 200-350 ml) or an equal volume of saline (Sal; 1 M) at a constant infusion rate during a "2,000-m" maximal ergometer row in five male oarsmen. Blood-gas variables were corrected ...
McKone E F - - 2002
Repeated bouts of submaximal exercise are an important part of most pulmonary rehabilitation programmes. Patients with moderate-to-severe cystic fibrosis (CF) often demonstrate oxygen desaturation during submaximal exercise, which may limit their ability to participate in these programmes. This study examines whether arterial desaturation contributes to submaximal exercise limitation by testing ...
Espersen Kurt - - 2002
Twelve subjects without and ten subjects with diving experience performed short diving-related interventions. After labeling of erythrocytes, scintigraphic measurements were continuously performed during these interventions. All interventions elicited a graduated and reproducible splenic contraction, depending on the type, severity, and duration of the interventions. The splenic contraction varied between approximately ...
Eichler Wolfgang - - 2002
OBJECTIVE: Measurement of functional residual capacity (FRC) is of considerable interest for monitoring ventilated patients in ICUs. However, the lack of instruments that can be used in the clinical setting has so far impeded the routine application of this measurement. It was the aim of our study to evaluate the ...
Wagner Peter D - - 2002
Pulmonary gas exchange and acid-base state were compared in nine Danish lowlanders (L) acclimatized to 5,260 m for 9 wk and seven native Bolivian residents (N) of La Paz (altitude 3,600-4,100 m) brought acutely to this altitude. We evaluated normalcy of arterial pH and assessed pulmonary gas exchange and acid-base ...
McIntyre Ian W - - 2002
The dive performance, oxygen storage capacity and partitioning of body oxygen reserves of one of the world's smallest mammalian divers, the star-nosed mole Condylura cristata, were investigated. On the basis of 722 voluntary dives recorded from 18 captive star-nosed moles, the mean dive duration (9.2+/-0.2 s; mean +/- S.E.M.) and ...
Medbø J I - - 2002
The performance of the Metamax I and the Metamax II portable analysers for measuring the O2 uptake has been examined during exercise. Healthy subjects ran on the treadmill or bicycled on ergometers while the O2 uptake was measured by the Metamaxes and also by the Douglas bag technique or the ...
Sternitzky R - - 2002
Previous studies demonstrated that naftidrofuryl increased the cutaneous and intramuscular tissue pO2 at rest. The presented open prospective pilot study is to investigate in apparently healthy subjects (n=12) whether naftidrofuryl also affects pO2 in situations of muscular stress. The pO2 is measured with a flexible probe in the anterior tibial ...
Bangsbo Jens - - 2002
It has been proposed that the activation state of pyruvate dehydrogenase (PDH) may influence the rate of skeletal muscle O2 uptake during the initial phase of exercise; however, this has not been directly tested in humans. To remedy this, we used dichloroacetate (DCA) infusion to increase the active form of ...
Enstipp M R - - 2001
Heart rate and dive behaviour were monitored in double-crested cormorants (Phalacrocorax auritus) during shallow (1 m) and deep diving (12 m), after breathing different gas mixtures, to investigate the role of depth and the accompanying changes in blood gas levels in cardiac and behavioural control during voluntary diving. Pre-dive heart ...
Mancuso Stefano - - 2002
Oxygen fluxes into and from root cells of Vitis rupestris (flooding sensitive), V. riparia (flooding tolerant) and V. vinifera (medium tolerance to flooding) were measured under different levels of O2 availability using a recently developed polarographic O2-selective, vibrating-microelectrode system. The system enables fluxes to be measured with a spatial resolution ...
Jørgensen C - - 2001
This study investigated physiological and behavioural aspects of diving development in pups of the harbour seal Phoca vitulina. Behavioural data (4280 h, 6027 dives) from time/depth recorders (N=13) deployed on pups aged 0-19 days are presented concomitantly with physiological measurements (N=8, sampled both early and late in the nursing period) ...
Mathes D D - - 2001
We compared outpatients transported to the postanesthesia care unit (PACU) while breathing room air to 2-4 L/min nasal cannula oxygen (O2) to test the hypothesis that routine supplemental O2 during transport is not required after general anesthesia in an ambulatory surgery center. We also examined whether the arbitrary arrival PACU ...
Gilmour K M - - 2001
That ventilation in fish is driven by O2 has long been accepted. The O2 ventilatory drive reflects the much lower capacitance of water for O2 than for CO2, and is mediated by O2 receptors that are distributed throughout the gill arches and that monitor both internal and external O2 levels. ...
Hart B J - - 2001
This is the first investigation of right ventricular (RV) myocardial oxygen supply/demand balance in a conscious animal. A novel technique developed in our laboratory was used to collect right coronary (RC) venous blood samples from seven instrumented, conscious dogs at rest and during graded treadmill exercise. Contributions of the RV ...
Hughson R L - - 2001
Increased aerobic production of ATP at the onset of exercise could be limited by availability of metabolic substrates independent of O2, or interaction between O2 and metabolic substrates. We point out the importance of feedback control to match O2 supply to demand and discuss metabolic control at the onset of ...
Grassi B - - 2001
The conflicting hypotheses on the limiting factors for skeletal muscle VO2 on-kinetics might be reconciled in a unifying scenario. Under "normal" conditions, during transitions to moderate intensity exercise, the limiting factor appears to be an inertia of oxidative metabolism. During transitions to exercise of higher metabolic intensity, O2 delivery could ...
Bennett A F - - 2001
Monitor lizards (Varanus exanthematicus) were used to examine the prioritization or additivity of the metabolic responses associated with exercise and digestion, either of which can elevate metabolic rate independently. Rates of oxygen consumption (V(O2)) and ventilation (V(E)) were measured in lizards during fasting exercise, postprandial rest and postprandial exercise. In ...
Anchisi S - - 2001
At a given steady O2 consumption (VO2) in normoxia, cardiac output (Q) is inversely proportional to arterial O2 concentration (CaO2), so that O2 delivery (QaO2=QCaO2) is kept constant and adapted to VO2. The matching between QaO2 and VO2 keeps O2 return (QvO2=QaO2-VO2) constant and independent of VO2 and haemoglobin concentration ...
Henderson K K - - 2001
The objective of these experiments was to determine whether living and training in moderate hypoxia (MHx) confers an advantage on maximal normoxic exercise capacity compared with living and training in normoxia. Rats were acclimatized to and trained in MHx [inspired PO2 (PI(O2)) = 110 Torr] for 10 wk (HTH). Rats ...
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