This thesis concerns an investigation of the ability of sheep to withstand cold. It includes studies of the initial cold resistance, the ability to acclimatize to cold, and of the variation within and between breeds of sheep. The cold resistance of shorn Scottish Blackface, Southdown and Welsh Mountain sheep, equal numbers on high or maintenance levels of nutrition, was measured by the rate of ...

The syndrome of high-altitude de-acclimatization commonly takes place after long-term exposure to high altitudes upon return to low altitudes. The syndrome severely affects the returnee's quality of life. However, little attention has been paid to careful characterization of the syndrome and their underlying mechanisms. Male subjects from Chongqing (n = 67, 180 m) and Kunming (n = 70, 1800 m) v...

OBJECTIVE Alterations in cerebral blood flow (CBF) and cerebral oxygenation are implicated in altitude-associated diseases. We assessed the dynamic changes in CBF and peripheral and cerebral oxygenation engendered by ascent to altitude with partial acclimatization and hyperventilation using a combination of near-infrared spectroscopy, transcranial Doppler ultrasound, and diffuse correlation spe...

The interindividual variation in ventilatory acclimatization to high altitude is likely reflected in variability in the cerebrovascular responses to high altitude, particularly between brain regions displaying disparate hypoxic sensitivity. We assessed regional differences in cerebral blood flow (CBF) measured with Duplex ultrasound of the left internal carotid and vertebral arteries. End-tidal...

2 Acclimatization to hypoxia requires time to complete the adaptation mechanisms that influence 3 oxygen (O2) transport and O2 utilization. Although decreasing hemoglobin (Hb) O2 affinity 4 would favor the release of O2 to the tissues, increasing Hb-O2 affinity would augment arterial O2 5 saturation during hypoxia. This study was designed to test the hypothesis that 6 pharmacologically increasi...

Phosphodiesterase-5 inhibitors decrease hypoxic pulmonary vasoconstriction under hypobaric hypoxia, but are not known to affect cerebral blood flow or oxygenation. The present study was designed to evaluate the effect of sildenafil on cerebral haemodynamics during acute exposure to altitude and after acclimatization. Ten subjects were studied 1 and 3 days after rapid ascent to 3480 m before and...

BACKGROUND Lack of validity in osteoarthritis pain models and assessment methods is suspected. Our goal was to 1) assess the repeatability and reproducibility of measurement and the influence of environment, and acclimatization, to different pain assessment outcomes in normal rats, and 2) test the concurrent validity of the most reliable methods in relation to the expression of different spinal...

Wyatt, FB. Physiological Responses to Altitude: A Brief Review. JEPonline 2014;17(1):90-96. Hypoxia has been defined as conditions with lower than normal oxygen availability. Altitude exposure and acclimatization have been areas of research for a considerable time. The immediate (acute) effects of lowered ambient pressure of oxygen (PO2) pertaining to the human response and the adaptations to p...