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Results 601 - 650 of 804
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McGrath J J - - 1992
The effects of carbon monoxide (CO) on blood carboxyhemoglobin (COHb) levels, though well studied at sea level, have not been investigated in populations at altitude. COHb levels were measured in laboratory rats following 6 wk exposure to either clean air or air containing 9 ppm CO at ambient altitude (3300 ...
Ingjer F - - 1992
Seven elite male cross-country skiers trained for 3 weeks at an altitude of 1900 m. Haemoglobin concentration ([Hb]), haematocrit (Hct) (obtained from venous blood), maximal oxygen uptake (VO2 max) and energy expenditure during a standard submaximal workload were measured before and after training at altitude, and 1 year later while ...
Schultz T W - - 1992
Eighty 2-, 3-, and 4-position monosubstituted phenols representing various substituents were evaluated for relative toxicity, log IGC50(-1), with a short-term static protocol in the Tetrahymena population growth inhibition bioassay. Quantitative structure-activity relationships (QSAR) were examined using the 1-octanol/water partition coefficient (log K(ow)) and ionization constant (pKa) as independent variables. Four ...
Pekkarinen J O - - 1992
The earmuff attenuation of acoustic impulses produced by large-caliber weapons was measured with a high-speed microcomputer controlled unit. The estimated accuracy was +/- 1 dB in peak sound-pressure level measurements. The peak levels outside earmuffs were 184 dB for the heavy bazooka and 172 dB for the hand-held bazooka (re: ...
Schena F - - 1992
To investigate the influence of a branched-chain amino acid (BCAA) supplementation on chronic hypoxia-related loss of body mass and muscle loss, 16 subjects [age 35.8 (SD 5.6) years] participating in a 21-day trek at a mean altitude of 3,255 (SD 458) m, were divided in two age-, sex- and fitness-matched ...
Reeves J T - - 1992
It seems unlikely that oxygen-limited metabolism explains the increased lactate concentrations in blood or muscle during exercise at high altitude compared with sea level values because: 1. Even marked hypoxia equivalent to that at the summit of Mt. Everest may not be sufficiently severe to impair function or to impair ...
Hirata K - - 1991
To understand the effects of high-altitude hypoxia on cardiac function and the change in cardiac function during high-altitude acclimatization, precise studies were first performed at greater than 5,000 m of altitude in Himalaya by 2-dimensional echocardiography. In addition to examining well-known indexes of cardiac function, the centerline method was used ...
Zeballos R J - - 1991
The effect of skin pigmentation on the reliability of noninvasive oximetry, especially during exercise and hypoxia, has not been thoroughly investigated. This is the first study, to our knowledge, that specifically addresses this question. Thirty-three young black men performed multistage, steady-state cycle ergometry, breathing gas mixtures simulating different altitudes: 33 ...
Mazzeo R S - - 1991
Exercise at high altitude is a stress that activates the sympathoadrenal systems, which could affect responses to acute altitude exposure and promote adaptations during chronic altitude exposure. However, catecholamine levels are not clearly described over time at high altitude. In seven male volunteers (23 yr, 72 kg), resting arterial norepinephrine ...
Milledge J S - - 1991
In a party of 17 subjects who travelled together to 4,500 m, hypoxic ventilatory response (HVR) and maximum oxygen consumption (VO2max) were measured before departure. HVR was measured under constant and varying alveolar carbon dioxide tension (PACO2) conditions. VO2max was measured by both standard expired gas collection technique on a ...
Kraemer W J - - 1991
The purpose of this study was to examine the immediate post-exercise effects of acute exposure to a simulated altitude of 4,300 m on plasma concentrations of beta-endorphin (beta-EP) and associated changes of adrenocorticotropin (ACTH), and cortisol to high intensity cycle exercise (i.e., stages of 90 and 100% peak Vo2). Exercise ...
Hegedus Z L - - 1991
Fluorescence spectrophotometry demonstrates that the levels of plasma soluble lipofuscins (SL) in patients with end-stage renal failure, undergoing continuous ambulatory peritoneal dialysis (CAPD) or haemodialysis (HD), remain significantly higher than in normal subjects. Plasma samples from these patients show the presence of SL generated from 3-hydroxy-anthranilic acid [excitation (ex) at ...
Bärtsch P - - 1991
A possible contribution of exercise to the fluid retention associated with acute mountain sickness (AMS) was investigated in 17 mountaineers who underwent an exercise test for 30 min on a bicycle ergometer with a constant work load of 148 +/- 9 (SE) W at low altitude (LA) and with 103 ...
Tewari S C - - 1991
Pulmonary function studies were done in 21 soldiers (low landers) posted at high altitude (average height 4773 metres) for prolonged periods (average 77.09 months), who had developed excessive polycythaemia, mean haemoglobin concentration being 23.06 g/dl. Studies revealed significant reduction in diffusion capacity of lungs which gradually returned to normal on ...
León-Velarde F - - 1991
We report the estimation of blood hemoglobin (Hb), arterial blood oxygen saturation (SaO2), and serum immunoreactive erythropoietin (siEPO) in a group of Peruvian workers residing in Cerro de Pasco at 4300 m showing "excessive erythrocytosis" (EE, Monge's disease, chronic mountain sickness). These estimates were compared with those of humans residing ...
Joseph K - - 1991
Ornithine decarboxylase (ODC) activity and polyamine levels were measured during early development of the frog, Microhyla ornata. ODC activity was found to be high and it showed three major peaks during the first 60 hr of development. Putrescine and spermidine levels increased gradually during the above period with little change ...
Kayser B - - 1991
The ultrastructure of the vastus lateralis muscle of Sherpas from Nepal [5 males; age 28 +/- 2.8 (SD) yr, indirect maximal O2 consumption 48.5 +/- 5.4 ml.kg(-1).min(-1)] was assessed and compared with those of sedentary lowlanders and of Caucasian climbers before and after high-altitude exposure. The mean cross-sectional area of ...
Brooks G A - - 1991
To evaluate the hypothesis that altitude exposure and acclimatization result in increased dependency on blood glucose as a fuel, seven healthy males (23 +/- 2 yr, 72.2 +/- 1.6 kg, mean +/- SE) on a controlled diet were studied in the postabsorptive condition at sea level (SL), on acute altitude ...
Williams T M - - 1991
Respiratory, metabolic, and cardiovascular responses to swimming were examined in two species of pinniped, the harbor seal (Phoca vitulina) and the California sea lion (Zalophus californianus). 1. Harbor seals remained submerged for 82-92% of the time at swimming speeds below 1.2 m.s-1. At higher speeds, including simulated speeds above 1.4 ...
Asmerom Y - - 1991
We report high precision Sr isotopic data on carbonates from the Neoproterozoic Shaler Group, Victoria Island, Northwest Territories, Canada. Lithostratigraphic correlations with the relatively well-dated Mackenzie Mountains Supergroup constrain Shaler deposition to approximately 770-880 Ma, a range corroborated by 723 +/- 3 Ma lavas that disconformably overlie Shaler carbonates and ...
Mink B D - - 1991
When writing an exercise prescription, the contributions of the pulmonary system are commonly forgotten. The lung has a tremendous potential to improve its work output, and its contributions are only realized when pulmonary disease or environmental stresses of altitude limit pulmonary performance. At altitudes of 5000 feet above sea level, ...
Young A J - - 1991
When unacclimatized lowlanders exercise at high altitude, blood lactate concentration rises higher than at sea level, but lactate accumulation is attenuated after acclimatization. These responses could result from the effects of acute and chronic hypoxia on beta-adrenergic stimulation. In this investigation, the effects of beta-adrenergic blockade on blood lactate and ...
Puppi A - - 1991
It was observed in rats, that following negative aeroionization heart frequency and the altitude of P-waves increased. After positive ionization these interrelationships took place inversely. As between these effects and the tendency of tissue redox-state potential changes correlation was seen, the results were grouped also on redox basis, independently on ...
Péronnet F - - 1991
A theoretical analysis of the effect of altitude on running performance is presented using a mathematical model we have recently described and validated (J. Appl. Physiol. 67: 453-465, 1989). This model relates the average power output available over a given running time for a given combination of anaerobic capacity, maximal ...
De Weerd P - - 1990
We measured 73.5% correct just noticeable differences (JNDs) in bar orientation with the method of constant stimuli and with a Wetherill and Levitt staircase procedure, using a total of 25 cats. For the same number of trials per threshold assessment, the variability of the threshold remained independent of the testing ...
Jordaan L C - - 1990
A survey by means of questionnaires was conducted along the Orange River to determine the extent of blackfly annoyance to livestock during 1984-1988. Severe annoyance reached peaks during September-November and increased over the years. Annoyance levels decreased with distance from the river with occasional severe annoyance as far away as ...
Trimmel M - - 1990
The occurrence of infraslow potential oscillations (ISPOs) of the brain was investigated during a listening and a resting condition in 44 subjects (Ss) with high (HAC) and low ability to concentrate (LAC). The occurrence of ISPOs was found in 36% of the Ss. While in the HAC group the occurrence ...
De Méo M - - 1990
Destruction procedures for dimethylsulfate (DMS), diethylsulfate (DES), methyl methanesulfonate (MMS), and ethyl methanesulfonate (EMS) have been investigated using treatment by 1 N NaOH, 1 N NH4OH, 1 M Na2CO3, and 1 M Na2S2O3. During the kinetic study of the destruction process, the determination of remaining concentrations of the alkylating agents ...
Kumar K V - - 1990
A review of case reports, hypobaric chamber training data, and experimental evidence indicated that the threshold for incidence of Altitude Decompression Sickness (DCS) was influenced by various factors such as prior denitrogenation, exercise or rest and period of exposure, in addition to individual susceptibility. Fitting these data with appropriate statistical ...
Malconian M - - 1990
To evaluate the effect of extreme altitude on cardiac function in normal young men, electrocardiograms were recorded at rest and during maximal exercise at several simulated altitudes up to the equivalent of the summit of Mt. Everest (240 torr or 8,848 m). The subjects spent 40 days in a hypobaric ...
Grover R F - - 1990
Skiing, which may involve strenuous exercise in the cold at high altitude, could place considerable stress on the coronary circulation. To explore this possibility, we obtained by telemetry electrocardiograms on 149 men during recreational skiing at altitudes above 3100 m (10 150 ft). Tachycardia was impressive; heart rate exceeded 80% ...
West J B - - 1990
Man can only survive and do work in the severe oxygen deprivation of great altitudes by an enormous increase in ventilation which has the advantage of defending the alveolar PO2 against the reduced inspired PO2. Nevertheless the arterial PO2 on the summit of Mt Everest at rest is less than ...
Ho Y B - - 1990
Before 1981, Pb in petrol in Hong Kong averaged about 0.84 g/l. Then the Pb level was stepwisely reduced and by early 1987, it was at 0.25 g/l. The effect of Pb reduction in petrol on the roadside environment was assessed by comparing the Pb content in kerbside dust samples ...
Shukitt-Hale B - - 1990
Ascents to altitudes above 3,050 m have been shown to cause adverse changes in symptoms and moods. The severity of these changes may depend not only on the altitude and rate of climb, but also on the length of stay and the effort expended to reach the desired altitude. In ...
Boutellier U - - 1990
The aim of the present investigation carried out on six members of the Swiss 1981 Mt. Lhotse Shar (8398 m) expedition was to assess the quantitative role of some of the determinants of VO2max at altitude. The loss of VO2max expected for the investigated altitude range was partially counterbalanced by ...
Mizuno M - - 1990
Morphological and biochemical characteristics of biopsies obtained from gastrocnemius (GAS) and triceps brachii muscle (TRI), as well as maximal O2 uptake (VO2 max) and O2 deficit, were determined in 10 well-trained cross-country skiers before and after a 2-wk stay (2,100 m above sea level) and training (2,700 m above sea ...
Richalet J P - - 1990
High altitude hypoxia induces a decrease in the cardiac chronotropic function at maximal exercise or in response to isoproterenol infusion, suggesting an alteration in the cardiac sympathetic activation. Iodine-123 metaiodobenzylguanidine [( 123I]MIBG) was used to map scintigraphically the cardiac sympathetic neuronal function in six male subjects (aged 32 +/- 7 ...
Kofstad J - - 1990
In May 1978 the two Italians, Messner and Habeler, climbed to the summit of Mt. Everest (8848 m above sea level) without use of supplementary oxygen. This must be the extreme limit of what the human organism can do. The upper limit of permanent living for man is considered to ...
Rani R - - 1990
Vesicular-arbuscular mycorrhizal fungi are widely distributed throughout the area studied including different altitudes ranging from sea level to 2500 ft above sea level. VAM fungi were recorded from 88% of the sites examined with Glomus fasciculatum and Glomus macrocarpum being the most commonly recorded. Mean species diversity was found to ...
Ahmad S - - 1990
Citrate anticoagulation has been used as an alternative to heparin for hemodialysis in high-risk patients; however, its use in hemofiltration has not been well studied. We examined citrate in 6 patients placed on slow hemofiltration for up to 6 h duration. During the experiments, the systemic citrate level increased from ...
Lee C - - 1990
The intention of this study was to determine the metabolic consequences of reduced frequency breathing (RFB) at total lung capacity (TLC) in competitive cyclists during submaximal exercise at moderate altitude (1520 m; barometric pressure, PB = 84.6 kPa; 635 mm Hg). Nine trained males performed an RFB exercise test (10 ...
Pigman E C - - 1990
A US Marine Corps Battalion Landing Team (BLT) of 638 men was deployed on a winter training exercise to an altitude of 2,065 to 2,620 m. Nine marines (1.4%) presented to the medical officers with incapacitating symptoms consistent with acute mountains sickness. Seven were treated with acetazolamide and experienced relief ...
Bebout D E - - 1989
Pulmonary gas exchange was studied in eight normal subjects both before and after 2 wk of altitude acclimatization at 3,800 m (12,470 ft, barometric pressure = 484 Torr). Respiratory and multiple inert gas tensions, ventilation, cardiac output (Q), and hemoglobin concentration were measured at rest and during three levels of ...
Kawashima A - - 1989
To verify the presence of the constitutional abnormality implicated in the pathogenesis of high-altitude pulmonary edema (HAPE), we evaluated the hemodynamic responses to hypoxia, hypobaria, and exercise in HAPE-susceptible subjects (HAPE-S). HAPE-S were five males with a history of HAPE. Five healthy volunteers who had repeated experiences of mountain climbing ...
Knutson C - - 1989
An increase in utilization of prenatal diagnosis was observed from 1985 to 1986 in South Carolina. The overall rate of 39.9% for 1986 is comparable with other areas of the U.S. Utilization was correlated with geographic residence, race, and referral source. While there was considerable variation in prenatal diagnostic test ...
Guezennec C Y - - 1989
Several studies have shown that hemorrheological parameters are modified by physical exercise and exposure to altitude hypoxia. These changes result in a decrease in red cell deformability (RCD). Similarly, it has been shown that a daily dietary fish oil supplement increases RCD. The purpose of this study was to evaluate ...
Bouissou P - - 1989
The renin-aldosterone system may be depressed in subjects exercising at high altitude, thereby preventing excessive angiotensin I (ANG I) and aldosterone levels, which could favor the onset of acute mountain sickness. The role of beta-adrenoceptors in hormonal responses to hypoxia was investigated in 12 subjects treated with a nonselective beta-blocker, ...
Cymerman A - - 1989
Chronic exposure to high altitude reduces maximal O2 uptake (VO2max). At extreme altitudes approaching the summit of Mt. Everest [inspiratory PO2(PIO2) = 43 Torr], mean VO2max have been determined to be 15.3 ml.kg-1.min-1 in two subjects who breathed 14% O2 at 6,300 m on Mt. Everest (West et al., J. ...
Shinomura Y - - 1989
Sizes of spleen and liver were studied by measuring spleen index calculated by multiplying the maximal length by the maximal width of the spleen and liver length at right mid-clavicular line below the costal margin using ultrasonography in 26 Papua New Guineans and in 25 Japaneses living in Papua New ...
Bermúdez De Castro J M - - 1989
The incidence of the different degrees of expression of Carabelli's trait in the deciduous and permanent dentitions was obtained on 651 skulls of three human prehistoric aboriginal samples from Gran Canaria (n = 329), Tenerife (n = 297) and La Gomera (n = 25) Islands. In the Gran Canaria sample, ...
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