Many pathological conditions exist where tissues exhibit hypoxia or low oxygen tension. Hypoxic hypoxia arises when there is a reduction in the amount of oxygen entering the blood and occurs in healthy people at high altitude. In 1946, research sponsored by the United States Navy led to the collection and ...

There is conflicting evidence whether hypoxia improves running economy (RE), maximal O(2) uptake (V(O)(2max)), haemoglobin mass (Hb(mass)) and performance, and what total accumulated dose is necessary for effective adaptation. The aim of this study was to determine the effect of an extended hypoxic exposure on these physiological and performance measures. ...

BACKGROUND: We wanted to determine whether current levels of fellowship training in hepato-pancreato-biliary (HPB) surgery will be sufficient to meet demand for HPB procedures in 2020. STUDY DESIGN: The Nationwide Inpatient Sample database for 1988 through 2003 was used to construct projections for the number of HPB procedures that will ...

Survival, haemolymph osmolality and the specific metabolic rate of the isopod Idotea chelipes from the brackish waters of the southern Baltic Sea (salinity 7 psu) were investigated after acclimation to different salinities in the range of 3-30 psu keeping other parameters constant (T=15 degrees C, full air saturation). Haemolymph osmolality ...

The assumption that buffering at altitude is deteriorated by bicarbonate (bi) reduction was investigated. Extracellular pH defense against lactic acidosis was estimated from changes (Delta) in lactic acid ([La]), [HCO3-], pH and PCO2 in plasma, which equilibrates with interstitial fluid. These quantities were measured in earlobe blood during and after ...

Studies performed over the past decade have yielded new information related to the physiological and metabolic adjustments made in response to both short- and long-term high-altitude exposure. These investigations have examined the potential mechanisms responsible for the alterations observed in such key variables as heart rate, stroke volume, cardiac output, ...

PURPOSE: Oxidative stress and erythropoietin (EPO) levels are increased following high altitude exposure. We hypothesized that the altitude-oxidative stress and EPO response would be associated with the presence or absence of acute mountain sickness (AMS) in subjects exposed at high altitude. METHODS: The study enrolled 29 healthy volunteers exposed at ...

PURPOSE: The purpose of this study was to determine whether seven intermittent altitude exposures (IAE), in combination with either rest or exercise training, improves time-trial exercise performance and induces physiologic adaptations consistent with chronic altitude adaptation at 4300 m. METHODS: Ten adult lowlanders (26 +/- 2 yr; 78 +/- 4 ...

The measurements of radioactive caesium contents in bottom sediments were carried out in four lakes. First samples (47) were taken in 1992-95. The repeat sampling (109) was performed from the same places in 2005. We examined eight chosen areas in these lakes. In six of them, we observed statistically significant ...

OBJECTIVE: To investigate the cause and nature of palpitations occurring at high altitude. METHODS: Implantable loop recorders were inserted subcutaneously in the left pectoral region of 9 healthy male volunteers. Subjects flew to Kathmandu (1,250 m) and then Lukla (2,800 m) before immediately commencing an identical ascent and descent profile ...

OBJECTIVE: To test the hypothesis that acclimatization to high altitude results in an improvement of the ventilatory threshold (VT). METHODS: Eight lowlanders underwent cardiopulmonary exercise testing with a cycle ergometer to determine VT and peak oxygen uptake (Vo2peak) in Coventry, United Kingdom (altitude: 80 m), on arrival in leh, india ...

Recent studies in normal participants have shown that right to left shunt blood vessels in the lung open up during exercise. We describe the first field study to investigate this phenomenon at altitude. This study aimed to assess the effect of altitude and partial acclimatization on inducible right to left ...

Hypoxemia is usually associated with acute mountain sickness (AMS), but most studies have varied in time and magnitude of altitude exposure, exercise, diet, environmental conditions, and severity of pulmonary edema. We wished to determine whether hypoxemia occurred early in subjects who developed subsequent AMS while resting at a simulated altitude ...

Aircraft cabins are pressurised to maximum effective altitudes of 2440 metres, resulting in significant decline in oxygen saturation in crew and passengers. This effect has not been studied in athletes. To investigate the degree of decline in oxygen saturation in athletes during long-haul flights. A prospective cross-sectional study. National-level athletes ...

Thesis (Ph.D. in Health and Sport Sciences)--University of Tsukuba, (A), no. 1583, 1996.3.25

The sex pheromone of the almond moth, Cadra cautella, is a blend of (Z,E)-9,12-tetradecadienyl acetate (Z9,E12-14:Ac, the major component capable of inducing attraction alone) and (Z)-9-tetradecenyl acetate (Z9-14:Ac, the minor component, which is unattractive alone but augments attraction of the major component). In this study, the ratio of the two ...

AIM: Acute mountain sickness (AMS) can result in pulmonary and cerebral oedema with overperfusion of microvascular beds, elevated hydrostatic capillary pressure, capillary leakage and consequent oedema as pathogenetic mechanisms. Data on changes in glomerular filtration rate (GFR) at altitudes above 5000 m are very limited. METHODS: Thirty-four healthy mountaineers, who ...

This study examines the potential for a ventilatory drive, independent of mean PCO2, but depending instead on changes in PCO2 that occur during the respiratory cycle. This responsiveness is referred to here as "dynamic ventilatory sensitivity." The normal, spontaneous, respiratory oscillations in alveolar PCO2 have been modified with inspiratory pulses ...

To test the hypothesis that the increased sympathetic tonus elicited by chronic hypoxia is needed to match O(2) delivery with O(2) demand at the microvascular level eight male subjects were investigated at 4559 m altitude during maximal exercise with and without infusion of ATP (80 mug (kg body mass)(-1) min(-1)) ...

PURPOSE: This study examined the effects of gender on graded exercise stress test (GXT) response in moderate-altitude (MA)-acclimatized cyclists during sea-level (SL) simulation. It was hypothesized that alterations in arterial saturation would relate to changes in VO2peak. METHODS: Twenty competitive cyclists (12 males, 8 females) who were residents of MA ...

Athletes regularly compete at 2,000-3,000 m altitude where peak oxygen consumption (VO2peak) declines approximately 10-20%. Factors other than VO2peak including gross efficiency (GE), power output, and pacing are all important for cycling performance. It is therefore imperative to understand how all these factors and not just VO2peak are affected by ...

Aerobic physiology at high altitudes has been studied in many animals. Prior work on laboratory-bred deer mice (a species with a wide altitudinal range) showed depression of aerobic capacity at high altitude, even after acclimation. However, wild deer mice show no reduction in thermogenic performance at high altitude, and performance ...

Rapid deployment of unacclimatized soldiers to high mountainous environments causes debilitating effects on operational capabilities (physical work performance), and force health (altitude sickness). Most of these altitude-induced debilitations can be prevented or ameliorated by a wide range of physiological responses collectively referred to as altitude acclimatization. Acclimatization to a target ...

"Live high-train low" (LH+TL) altitude training allows athletes to "live high" for the purpose of facilitating altitude acclimatization, as characterized by a significant and sustained increase in endogenous erythropoietin and subsequent increase in erythrocyte volume, while simultaneously enabling them to "train low" for the purpose of replicating sea-level training intensity ...

Aerobic exercise capacity is decreased at altitude because of combined decreases in arterial oxygenation and in cardiac output. Hypoxic pulmonary vasoconstriction could limit cardiac output in hypoxia. We tested the hypothesis that acetazolamide could improve exercise capacity at altitude by an increased arterial oxygenation and an inhibition of hypoxic pulmonary ...

Floating marine debris, particularly derelict fishing gear, is a hazard to fish, marine mammals, turtles, sea birds, coral reefs, and even human activities. To ameliorate the economic and environmental impact of marine debris, we need to efficiently locate and retrieve dangerous debris at sea. Guided by satellite-derived information, we made ...

For more than 60 years, muscle mechanical efficiency has been thought to remain unchanged with acclimatization to high altitude. However, recent work has suggested that muscle mechanical efficiency may in fact be improved upon return from prolonged exposure to high altitude. The purpose of the present work is to resolve ...

Many arboreal primates descend to the ground, a custom that may occur more frequently in disturbed habitats, and in the presence of researchers to whom the primates are habituated. In this paper, we describe opportunistic observations of ground use in two groups of northern muriquis (Brachyteles hypoxanthus) at the RPPN ...

The factors determining maximal oxygen consumption were explored in eight endurance trained subjects (TS) and eight untrained subjects (US) exposed to moderate acute normobaric hypoxia. Subjects performed maximal incremental tests at sea level and simulated altitudes (1,000, 2,500, 4,500 m). Heart rate (HR), stroke volume (SV), cardiac output (.Q), arterialized ...

The regulation of cerebral blood flow (CBF) is a complex process that is altered significantly with altitude exposure. Acute exposure produces a marked increase in CBF, in proportion to the severity of the hypoxia and mitigated by hyperventilation-induced hypocapnia when CO(2) is uncontrolled. A number of mediators contribute to the ...

The objective of this study was to determine the effect of acute moderate hypoxia and rest duration on performance and on the accumulated oxygen deficit (AOD) in high-intensity intermittent efforts. After preliminary tests, 2 groups of nonacclimatized men (resident at 690 m above sea level) carried out 3 randomized protocols ...

Quarantine measures including treatments are applied to exported fruit and vegetable commodities to control regulatory fruit fly pests and to reduce the likelihood of their introduction into new areas. Nonhost status can be an effective measure used to achieve quarantine security. As with quarantine treatments, nonhost status can stand alone ...

We present a case of Ebstein's anomaly revealed by symptoms occurring at high altitude. A 63 year old male with no previous symptoms of cardiovascular disease developed acute severe shortness of breath when walking up a flight of stairs at an altitude of 2500 m. Echocardiography showed apical displacement of ...

After a century of polar exploration, the past decade of satellite measurements has painted an altogether new picture of how Earth's ice sheets are changing. As global temperatures have risen, so have rates of snowfall, ice melting, and glacier flow. Although the balance between these opposing processes has varied considerably ...

Highland natives show unique breathing patterns and ventilatory responses at altitude, both at rest and during exercise. For many ventilatory traits, there is also significant variation between highland native groups, including indigenous populations in the Andes and Himalaya, and more recent altitude arrivals in places like Colorado. This review summarizes ...

This study tested the hypothesis that maximal oxygen uptake (VO(2max)) and performance increase upon altitude acclimatization at moderate altitude. Eight elite cyclists were studied at sea level, and after 1 (Day 1), 7 (Day 7), 14 (Day 14) and 21 (Day 21) days of exposure to 2340 m. Capillary blood ...

Systematic investigations of (137)Cs and (134)Cs activity concentrations in potatoes (Solanum tuberosum) for the post-Chernobyl period (1986-2005) in the Republic of Croatia are summarized. The correlation between (137)Cs activity concentrations in fallout and potatoes, has been found to be very good, the correlation coefficient being r = 0.88 with P(t) ...

Mammals native to high altitude (HA) exhibit larger lung volumes than their lowland counterparts. To test the hypothesis that adaptation induced by HA residence during somatic maturation improves pulmonary gas exchange in adulthood, male foxhounds born at sea level (SL) were raised at HA (3,800 m) from 2.5 to 7.5 ...

Oxygen delivery (DO2) calculated from cardiac output, haematocrit (Hct) and arterial oxygen saturation (SaO2), has been obtained on six subjects at sea level (London) and after slow ascent to 5000 meters (Chamlang base camp) at rest and during mild exercise (25 watts and 50 watts). Haematocrit was increased in all ...

We found low, albeit significant, genetic differentiation among turbot (Psetta maxima) in the Baltic Sea but in contrast to earlier findings we found no evidence of isolation by distance. In fact temporal variation among years in one locality exceeded spatial variation among localities. This is an unexpected result since adult ...

Rainfall-runoff processes in a small oil palm catchment (8.2 ha) in Johor, Malaysia were examined. Storm hydrographs show rapid responses to rainfall with a short time to peak. The estimated initial hydrologic loss for the oil palm catchment is 5 mm. Despite the low initial loss, the catchment exhibits a ...

For nearly 40 years, scientists and elite endurance athletes have been investigating the use of altitude in an effort to enhance exercise performance. While the results of many early studies on the use of altitude training for sea level performance enhancement have produced equivocal results, newer studies using the 'live ...

Because of lacking ventilatory stimulation by sex hormones in postmenopausal women (PW), one might expect a lowered arterial oxygen saturation (S(O(2))) in hypoxia and therefore a stronger erythropoietic reaction than in young women (YW). Nine untrained (UTRPW) and 11 trained (TRPW) postmenopausal altitude residents (2600 m) were compared to 16 ...

Long-distance flights can cause a number of clinical problems in both passengers and crewmembers. Jet lag as well as mild hypoxia resulting from incomplete cabin pressurization could contribute to these problems. The objective of this study was to assess, using a chronobiological approach, the clinical impact of diurnal hypobaric, hypoxic ...

The purpose of this case study was to profile maximal exercise and the incidence of exercise-induced arterial hypoxemia (EIAH) at three different altitudes within a group of competitive cyclists residing and training at 1,500 m. Ten male cyclists (category I or II professional road cyclists: ages, 27.7 +/- 6.1; weight, ...

Long-term intermittent hypoxia, characterized by several days or weeks at altitude with periodic stays at sea level, is a frequently occurring pattern of life in mountainous countries demanding a good state of physical performance. The aim of the study was to determine the effects of a typical South American type ...

The ratio of oxygenated to total haemoglobin (Hb), or rSO2, obtained by near infrared spectroscopy (NIRS), includes both arterial and venous blood of the region examined. The relationship of arterial oxygen extraction, E, and saturation, SaO2, to rSO2 can be expressed, for normally functioning tissue, as E = 1.39 (1 ...

The aim of this study is to determine the qualitative and quantitative changes of alkaline phosphatase (ALP) that occur in the Gingival Crevicular Fluid (GCF) in hypobaric-hypoxic conditions (high altitude). Hypoxia affects systemic adaptation responses in different organs. We examined 17 Caucasians subjects, of whom 13 were mountain climbers (1 ...

The aim of the present study was to identify the effects of physical exercise on PSA serum levels and the diagnostic validity of PSA in the screening of prostate cancer in subjects undergoing physical exercise during chronic hypoxia. The study was performed during trekking between 3,200 and 5,600 meters of ...

Semaphore crabs (Heloecius cordiformis), soldier crabs (Mictyris platycheles), ghost shrimps (Trypaea australiensis), pygmy mussels (Xenostrobus securis), and polychaetes (Eunice sp.), key benthic prey items of predatory fish commonly found in estuaries throughout southeastern Australia, were exposed to dissolved (109)Cd and (75)Se for 385 h at 30 k Bq/l (uptake phase), ...