Search Results
Results 501 - 550 of 813
< 6 7 8 9 10 11 12 13 14 15 16 >
Bashir N - - 1996
The purpose of this study was to examine the effects of exercise on anterior pituitary hormones (adrenocorticotropic hormone (ACTH), leutinizing hormone (LH) and growth hormone) as well as on cortisol at low altitude (350 meters below the sea level) and to compare these effects with those at a moderate level ...
Cibella F - - 1996
1. The present investigation was conducted to test the hypothesis that the respiratory system is stressed more during exhaustive exercise in chronic hypoxia than in normoxia. 2. Four healthy male subjects (aged 33-35 years) exercised on a cycle ergometer at 75% of the local maximum oxygen consumption (Vo2,max) until exhaustion, ...
Huch R - - 1996
Advice to pregnant women wishing to exercise at altitude is based only on isolated observations and a handful of systematic studies, none of which have explored the limits of combined exercise and altitude exposure in human pregnancy (ie, at maximal exercise and maximal altitude). Guidelines must therefore be based on ...
Gunga H C - - 1996
It was hypothesized that, in shift workers with a history of intermittent hypoxic stress (working 10 days at > 3,600 m, then resting for 4 days at sea level) for > 5 yr, the initial erythropoietin (EPO) response and the changes in central venous pressure (CVP) are different from those ...
Podolsky A - - 1996
Ventilation-perfusion (VA/Q) mismatch has been shown to increase during exercise, especially in hypoxia. A possible explanation is subclinical interstitial edema due to high pulmonary capillary pressures. We hypothesized that this may be pathogenetically similar to high-altitude pulmonary edema (HAPE) so that HAPE-susceptible people with higher vascular pressures would develop more ...
Asztely F - - 1996
We have investigated the interaction between long-term potentiation (LTP) and paired-pulse facilitation (PPF) in the hippocampal CA1 region under different conditions of initial PPF. PPF is a short lasting presynaptic alteration in synaptic efficacy, determined by the presynaptic release probability, where a high and low PPF indicate a low and ...
Holman E W - - 1996
Taxa of high rank tend to originate at earlier times in the fossil record than do taxa of lower rank. Statistical analysis of published stratigraphic ranges shows that the early origin of higher taxa is a secondary consequence of taxonomic structure. For instance, the probability that the origination of an ...
Webb J T - - 1996
INTRODUCTION: Prevention of decompression sickness (DCS) during exposure to altitude equivalents of 30,000 ft (9144 m) requires extensive denitrogenation. In preparation for extravehicular activity (EVA), present NASA policy is to denitrogenate using a 10.2 psia staged decompression of the entire shuttle for at least 12 h, including 100 min of ...
Wu Y - - 1996
Previous work on the growth biophysics of maize (Zea mays L.) primary roots suggested that cell walls in the apical 5 mm of the elongation zone increased their yielding ability as an adaptive response to low turgor and water potential (psi w). To test this hypothesis more directly, we measured ...
Kramer M R - - 1996
Patients with advanced chronic obstructive lung disease often require oxygen supplementation, which has been shown to increase survival but requires a device such as an oxygen tank and tubing. The inspired partial pressure of oxygen depends on barometric pressure, which is related directly to altitude. At the Dead Sea, located ...
Young A J - - 1996
This study investigated whether autologous erythrocyte infusion would ameliorate the decrement in maximal O2 uptake (VO2max) experienced by lowlanders when they ascend to high altitude. VO2max was measured in 16 men (treadmill running) at sea level (SL) and on the 1st (HA1) and 9th (HA9) days of high-altitude (4,300 m) ...
Gippenreiter E - - 1996
The countries of the former Soviet Union have a long history of studies in high-altitude medicine and physiology, but much of the information is difficult to obtain in the West because of the inaccessibility of the journals and the lack of familiarity with the language. The purpose of present review ...
Le Gallais D - - 1996
The pathophysiological process of exercise-induced death in subjects with sickle cell trait (SCT) remains unclear. Concerning the cause of death, authors have suggested stressful environmental conditions such as altitude, heat and humidity, or abnormal patient conditions such as deconditioning, fatigue, and disease. These conditions are thought to lead to hypoxemia, ...
Jensen J B - - 1996
The fractional increase in cerebral blood flow (CBF) velocity (VCBF) from the control value with 5-min steps of isocapnic hypoxia and hyperoxic hypercapnia was measured by transcranial Doppler in six sea-level native men before and during a 5-day sojourn at 3,810 m altitude to determine whether cerebral vasoreactivity to low ...
Guo B Z - - 1996
Kernels of corn population GT-MAS:gk, resistant to aflatoxin B1 production by Aspergillus flavus, and susceptible Pioneer hybrid 3154 were tested for aflatoxin when incubated under different relative humidities (RH). High aflatoxin levels were not detected in either genotype at RH < 91%. Resistance in GT-MAS:gk was consistent across all RH ...
Conkin J - - 1996
One consequence of the NASA tissue ratio (TR) model is that calculated probability of decompression sickness [P(DCS)] is constant in tests at different ambient pressures so long as the ratio of P1N2 to P2 is the same in each test; P1N2 is N2 pressure in the 360 minute half-time compartment, ...
Roberts A C - - 1996
To test the hypothesis that altitude exposure increases glucose utilization and that this increment is mediated by a beta-adrenergic mechanism, the effects of hypobaric hypoxia and beta-blockade on glucose rates of appearance (Ra), disappearance (Rd), oxidation (Rox), and leg uptake [G = 2(arteriovenous glucose difference)(1 - leg blood flow)] were ...
Jeng W L - - 1996
One of the major industries in southern Taiwan is pigfarming along the Kaoping River; some two million animals are being raised along the river banks. Excretions from pigs, treated and untreated, are discharged directly into the river and eventually carried to the sea. Twenty-four surface sediments and one sediment core ...
Steinacker J M - - 1996
Hypoxic ventilatory response (HVR) was examined before and after acclimatization to high altitude. Transient hyperoxic switches according to Dejours's technique were used to examine the contribution of HVR to the hyperpnoea of increasing exercise intensities. Ten mountaineers were exposed to hypoxia (oxygen fraction in inspired gas. F1O2 = 0.11, 79 ...
Burtscher M - - 1996
After more than 25 years of research of altitude training (AT) there is no consensus regarding either the training programme at altitude or the effects of AT on performance at sea level. Based on a review of the research work on AT, we investigated combined base training and interval training ...
Kayser B - - 1996
In acclimatized humans at high altitude the reduction, compared to acute hypoxia, of the blood lactate concentration (la) at any absolute oxygen uptake (VO2), as well as the reduction of maximum la (lamax) after exhaustive exercise, compared to both acute hypoxia or normoxia, have been considered paradoxical, and these phenomena ...
Steinacker J M - - 1996
Studies were made of pulmonary diffusion capacity and oxygen transport before and after an expedition to altitudes at and above 4900 m. Maximum power (Pmax) and maximal oxygen uptake (VO2max) were measured in 11 mountaineers in an incremental cycle ergometer test (25W.min-1) before and after return from basecamp (30 days ...
Naughton M T - - 1995
Hypobaric hypoxemia is experienced by passengers during commercial aircraft flight. In order to assess the extent of hypoxemia and to test whether hypobaric hypoxia can be accurately estimated at sea level, the results of the normobaric hypoxia altitude simulation test (N-HAST) were compared with those of the hypobaric hypoxia altitude ...
Wood R J - - 1995
Anecdotal evidence suggests that the 610 m altitude of the Australian Institute of Sport in Canberra may affect athletic performances, despite the lack of theoretical evidence to support this. Also, the lower air resistance at altitude could alter the mechanics of air-braked exercise ergometers. Therefore, this study compared performance on ...
Porcelli M J - - 1995
Acute mountain sickness (AMS) affects, to varying degrees, all travelers to high altitudes (elevations greater than 5280 feet). In a small percentage of patients, AMS can lead to high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE). Symptoms of AMS range from a combination of headache, insomnia, anorexia, nausea, and ...
Rao A R - - 1995
Three measures of reciprocity, denoted s2, s3, and s4, that are applicable to both simple and weighted networks are considered here. By reciprocity I mean symmetry or mutuality of ties between different vertices of the network. These measures have simple formulas except in some extreme situations and can be used ...
Hohenhaus E - - 1995
Reduced tolerance to high altitude may be associated with a low ventilatory and an increased pulmonary vascular response to hypoxia. We therefore, examined whether individuals susceptible to acute mountain sickness (AMS) or high altitude pulmonary oedema (HAPE) could be identified by noninvasive measurements of these parameters at low altitude. Ventilatory ...
Allegra L - - 1995
It is well-known that many patients with asthma undergo clinical improvement during a stay at high altitude. At high altitude, the atmospheric and climatic conditions (such as hypoxia, cold and dry air inhalation) could modify the bronchial responsiveness in asthmatics. Our study was designed to assess the difference in bronchial ...
Coote J H - - 1995
Acute mountain sickness (AMS) has long been recognised as a potentially life-threatening condition afflicting otherwise healthy normal individuals who ascend rapidly to high altitude where the partial pressure of oxygen (pO2) in the air is reduce. The symptoms of AMS (e.g. headache, poor appetite and nausea, fatigue and weakness, dizziness ...
Savard G K - - 1995
The purpose of this study was to assess the effects of acclimatization to extreme altitude on the cardiovascular system, using vagal and adrenergic blockade and acute restoration of normoxia during exercise to maximum with one and two legs. Fourteen climbers on an expedition to the Himalayas were studied at a ...
Jaworska J S - - 1995
The acute toxicity of aliphatic and aromatic mono and diesters in two eucaryotic organisms was compared. The test systems were the static 2-d Tetrahymena pyriformis 50% population growth impairment (IGC50(-1)) assay, and the flow-through 4-d Pimephales promelas 50% mortality (LC50(-1)) assay. In ciliates, esters act via the nonpolar narcosis mechanism ...
Mazzeo R S - - 1995
This investigation examined the relationship between alterations in plasma norepinephrine associated with 21 days of high-altitude exposure and muscle sympathetic activity both at rest and during exercise. Healthy sea level residents, divided into a control group (n = 5) receiving a placebo or a drug group (n = 6) receiving ...
Davis H Q - - 1995
This study determined if visual performance with Aviator Night Vision Imaging System (ANVIS) was degraded by the degree of hypoxia experienced at the maximum flight altitude currently authorized (U.S. Army regulations) without supplemental oxygen. Visual acuity and contrast sensitivity with ANVIS were tested under simulated starlight and full moonlight illumination ...
Favier R - - 1995
Maximal O2 uptake (VO2max) was determined on a bicycle ergometer in chronic hypoxia (CH) and during acute exposure to normoxia (AN) in 50 healthy young men who were born and had lived at 3,600 m altitude (La Paz, Bolivia). VO2max was significantly improved (approximately 8%) by AN. However, the difference ...
Artal R - - 1995
OBJECTIVE: The purpose of this study was to compare maternal cardiopulmonary and fetal responses of lowlander pregnant women in the third trimester to exercise at sea level and at an altitude of 6000 feet. STUDY DESIGN: Seven women at 33.86 +/- 1 weeks' gestation performed a symptom-limited maximal exercise test ...
Terasawa K - - 1995
To examine cardiopulmonary function during exercise in a mountainous region at moderate altitude, we measured cardiac frequency, oxygen consumption (VO2), and percentage arterial hemoglobin oxygen saturation (%SaO2) before and after a bicycle race with a starting point at 638 m and finishing point at 1980 m. The time required to ...
Nimmo M A - - 1995
A simple study monitoring altitude acclimatization, which is not intrusive to the athlete's training, is described. Particular attention is drawn to the change in production of lactate in response to steady state exercise, before and after altitude. The results suggest that a more thorough assessment of aerobic ability at altitude ...
Gunga H C - - 1995
For over 52 years, the work of Nathan Zuntz (1847-1920) covered an amazingly wide spectrum of research fields; metabolism, nutrition, respiration, blood gases, exercise, and high altitude physiology were the main themes. Zuntz achieved fame for his invention of the Zuntz-Geppert respiratory apparatus in 1886 and the first Laufband (treadmill) ...
West J B - - 1995
Recently there has been increasing commercial activity at altitudes of 3500-6000 m. Examples include new mines in northern Chile at altitudes of about 4500 m. Because the workers come from sea level, intolerance of the high altitude is a major problem. This degree of hypoxia reduces work capacity, mental efficiency ...
Kashimura O - - 1995
We examined the effects of exercise training on pulmonary arterial blood pressure (Ppa) and on adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (GMP) concentrations in lung tissue at rest and during exercise under hypoxic conditions in catheter-implanted rats. Male Wistar rats were divided into an exercise-trained group (ET, n ...
Takeoka M - - 1995
Physiological changes were investigated in the cardio-respiratory function of competitors in a bicycle race which involved not a flat course but ascending a mountain, from 1400 m to 2800 m. Heart rate throughout the race, arterial oxygen saturation and pulmonary function before and after the race of well trained competitors ...
Saito S - - 1995
The recent expansion in the geographical areas open to human activity has made it desirable to have an objective method to evaluate the degree of high-altitude acclimatization. In this study, we measured the arterial oxygen saturation value at rest and just after exercise in healthy high-altitude trekkers using a transportable ...
Capelli C - - 1995
The present world record for 1 h unaccompanied cycling (55.291 km) was set by T. Rominger in November 1994 at sea level (Bordeaux, France). However, maximal aerobic cycling performances can be expected to increase at altitude because, for a given air temperature, air density decreases more than VO2max. The combined ...
Shih Y F - - 1995
Visual-training methods in management of myopia are suggested as possibly leading to normal vision or an improvement in the refractive state. The purpose of this work was to investigate the hypothesis that a Qi-Qong ocular exercise improves visual function by training the accommodation bias. Variations of pupil size, accommodative amplitude, ...
Niu W - - 1995
The physiological response to submaximal and maximal exercise was assessed in lowlanders and Tibetans at low (500 m above sea level) and high altitude (HA, 3,680 m). The times spent at HA by the lowland migrators was 8 days (n = 60), 7 months (n = 60, same group), 15 ...
Takebayashi T - - 1995
We investigated the effect of local injections of danazol suspension (DZS) into the uterine cervix. In the cervix, danazol (DZ) reached high concentrations 1 and 4-6 h after injection; then it decreased. In the endometrium, the DZ level reached a peak 1 h after injection, and then declined. On the ...
Bijl D - - 1994
BACKGROUND: In order to evaluate a pulmonary rehabilitation program (PRP) at moderate altitude (1560 m) 62 patients with obstructive lung disease were asked to participate; 37 patients completed a 1-year follow-up at sea level, and 25 patients dropped out. The exercise training program lasted for 10 weeks and consisted of ...
Beran R F - - 1994
BACKGROUND: To ensure optimal performance, it is imperative to properly maintain the condition of ophthalmic diamond scalpels. Refractive surgeons are often confronted with conflicting cleaning recommendations from manufacturers. The problem encountered is to maximize cleaning while minimizing trauma to the diamond to maintain its longevity. METHODS: The author describes a ...
Noel-Jorand M C - - 1994
Respiratory sensation was studied in European low-landers at an altitude of 4382 m after a helicopter flight in order to investigate the acute and prolonged effects of high altitude hypoxia. At rest the ability to detect four inspiratory resistive loads can be used to create a sensitivity index P(A) without ...
Ge R L - - 1994
To examine the hypothesis that the pathway of adaptation to high altitude in natives differs considerably from that in newcomers, we measured maximal O2 uptake (VO2max), minute ventilation, anaerobic threshold (AT), blood lactate, and blood gases during maximal exercise in 17 lifelong Tibetan residents and 14 acclimatized Han Chinese newcomers ...
< 6 7 8 9 10 11 12 13 14 15 16 >