Body temperature drops dramatically during hibernation, but the heart retains the ability to contract and is resistant to induction of arrhythmia. Although adaptive changes in the heart prior to hibernation may be involved in the cold-resistant property, it remains unclear whether these changes are sufficient for maintaining cardiac pulsatility under an extreme hypothermic condition. We forcibl...

Previous research has suggested that arctic populations have elevated metabolic rates in response to their cold, marginal climate. Recent studies of indigenous Siberian groups have confirmed these earlier findings and have shed light on the mechanisms through which northern populations adapt to their environments. Indigenous Siberians show significant elevations in basal metabolic rate compared...

Plasma concentrations of thyroid hormones (TH) were investigated during the extended posthatching developmental period (approximately 11 months) of a semi-altricial bird species, the king penguin (Aptenodytes patagonicus). The first period of growth in summer was marked by a progressive rise in plasma T4 concentration that paralleled rapid increases in body mass and in structural and down growt...

BACKGROUND The low survival rate of in vitro regenerated Panax ginseng plantlets after transfer to soil is the main obstacle for their successful micropropagation and molecular breeding. In most cases, young plantlets converted from somatic embryos are transferred to soil. METHODS In vitro thickened taproots, which were produced after prolonged culture of ginseng plantlets, were transferred t...

Acclimatization was studied in hearing-impaired patients with no previous hearing aid (HA) experience who were fit bilaterally with either wide dynamic range multichannel compression (WDRMCC) or linear amplification (LA) HAs. Throughout 40 weeks of normal HA use, we monitored changes in nonsense syllable perception in speech-spectrum noise. Syllable recognition for WDRMCC users improved by 4.6%...

This study had two goals: 1) measure hematologic changes with high-altitude acclimatization in horses; and 2) assess the effect of 9 days at high altitude on subsequent athletic performance at low altitude. Six horses performed standardized exercise tests on a dirt track (before and during time at altitude) and treadmill (pre- and postaltitude exposure). Resting and immediate postexercise blood...

ANTHONY,ADAM,EUGENEACKERMAN AND G.K.STROTHER. Effects of altitude acclimatization on rat myoglobin. Changes in myoglobin content of skeletal and cardiac muscle. Am. J. Physiol. 196(s): 512-516. 1959. -Analyses were made of myoglobin content of rat skeletal and cardiac muscle following continuous exposure to simulated altitudes of 18,000 feet for a Q--IO-week period. About five dozen rats were u...

The Cape porcupine Hystrix africaeaustralis is a large (11-18 kg), nocturnal, burrowing and group-living rodent. It experiences a metabolic response to seasonal acclimatization and is a hind gut fermenter. Changes in the urinary electrolyte and free urinary catecholamine concentrations of Cape porcupines were related to combined changes of ambient temperature and photoperiod regime. Three group...

The repercussions of hypobaric hypoxia are dependent upon two factorstime and intensity of exposure. The effects of intensity i.e. variation of altitude are yet unknown although it is a significant factor in terms of acclimatization protocols. In this study we present the effects of acute (24 h) exposure to high (10,000 ft), very high (15,000 ft) and extreme altitude (25,000 ft) zones on lung a...

and to renal clearance; the binding of agents to proteins; microbial resistance; defense mechanisms of the host and the nature of the lesions in relation to chemotherapy; chemoprophylaxis of meningococcal, bacillary dysentery and streptococcal infections; chemotherapy in malaria and in rickettsial and viral diseases; transcutaneous anti-biotic treatment; and experimental and clinical evaluation...