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Avian pulmonary capillaries differ from those of mammals in three important ways. The blood-gas barrier is much thinner, it is more uniform in thickness, and the capillaries are far more rigid when their transmural pressure is altered. The thinness of the barrier is surprising because it predisposes the capillaries to stress failure. A possible mechanism(More)
To attempt to explain the difference in intrinsic (untrained) endurance running capacity in rats selectively bred over seven generations for either low (LCR) or high running capacity (HCR), the relationship among skeletal muscle capillarity, fiber composition, enzyme activity, and O(2) transport was studied. Ten females from each group [body wt: 228 g(More)
Skin plays an essential role, mediated in part by its remarkable vascular plasticity, in adaptation to environmental stimuli. Certain vertebrates, such as amphibians, respond to hypoxia in part through the skin; but it is unknown whether this tissue can influence mammalian systemic adaptation to low oxygen levels. We have found that epidermal deletion of(More)
When exposed to a hypoxic environment the body's first response is a reflex increase in ventilation, termed the hypoxic ventilatory response (HVR). With chronic sustained hypoxia (CSH), such as during acclimatization to high altitude, an additional time-dependent increase in ventilation occurs, which increases the HVR. This secondary increase persists after(More)
Flying requires enormous energy and some birds have higher mass-specific maximal oxygen consumptions than any mammal. The bird lung is very efficient partly because of an extremely thin blood-gas barrier so that some birds have thinner barriers than any mammals. We show here that in addition to the total barrier being very thin, the interstitium which is(More)
The pathogenesis of high-altitude pulmonary oedema (HAPE) is disputed. Recent reports show a strong correlation between the occurrence of HAPE and pulmonary artery pressure, and it is known that the oedema is of the high-permeability type. We have, therefore, proposed that HAPE is caused by ultrastructural damage to pulmonary capillaries as a result of(More)
Recently, inflammatory processes have been shown to increase O(2)-sensitivity of the carotid body during chronic sustained hypoxia [Liu, X., He, L., Stensaas, L., Dinger, B., Fidone, S., 2009. Adaptation to chronic hypoxia involves immune cell invasion and increased expression of inflammatory cytokines in rat carotid body. Am. J. Physiol. Lung Cell Mol.(More)
Previous physiological studies suggest that avian pulmonary capillaries behave like almost rigid tubes. We made morphometric measurements to determine the diameter of the capillaries in chicken lungs when the transmural pressure was altered over a wide range. The diameter of avian pulmonary capillaries increased by only 13% when the pressure inside them was(More)
The lungs of domestic chickens were perfused with blood or dextran/saline and the pulmonary artery pressure (P(a)) and venous pressure (P(v)) were varied in relation to air capillary pressure (P(A)). In Zone 3 conditions, pulmonary vascular resistance (PVR) was virtually unchanged with increases in either P(a) or P(v). This is very different behavior from(More)