The effects of hypoxia on lung and airway mechanics remain controversial, possibly because of the confounding effects of competing reflexes caused by systemic hypoxemia. We compared the effects of systemic hypoxemia with those of unilateral alveolar hypoxia (with systemic normoxemia) on unilateral respiratory system impedance (Z) in intact, anesthetized dogs. Independent lung ventilation was ob...

The purpose of this study was to investigate the potential responses of the cardiovascular system and regional blood flow to hypoxic hypoxia (BB) and to carbon monoxide (CO)-induced hypoxia (COH). Ten anesthetized cats were studied under two nonnoxic (control: CONT) and two hypoxic conditions. Four types of radioactive micro spheres were used to measure regional blood flow during CONT an...

Although many effects of both acute and chronic hypoxia on the circulation are well characterized, the distribution and regulation of blood flow (BF) heterogeneity in skeletal muscle during systemic hypoxia is not well understood in humans. We measured muscle BF within the thigh muscles of nine healthy young men using positron emission tomography during one-leg dynamic knee extension exercise i...

The mechanisms controlling cardiovascular responses to hypoxia are poorly understood. We studied effects of parasympathetdc blockade by atropine (Px) and sympathectomy by adrenalectomy plus 6-hydroxydopamine (Sx) in five unanesthetdzed dogs acutely exposed to hypoxic conditions (Paoi 35 mm Hg). In intact dogs during hypoxia, heart rate increased by 55 ± 10 (SEM) beats/min. After either Px or Sx...

We tested the hypotheses that, in hypoxic young pigs, reductions in cardiac output restrict systemic oxygen transport to a greater extent than does hypoxia alone and that compensatory responses to this restriction are more effective in higher than in lower priority vasculatures. To study this, 10- to 14-day-old instrumented awake hypoxic (arterial oxygen tension = 39 Torr) pigs were exposed to ...

Whole brain radiation therapy (WBRT) is commonly used for treatment of primary and metastatic brain tumors; however, cognitive impairment occurs in 40-50% of brain tumor survivors. The etiology of the cognitive impairment following WBRT remains elusive. We recently reported that radiation-induced cerebrovascular rarefaction within hippocampal subregions could be completely reversed by systemic ...

The mechanisms underlying the pulmonary arterial pressor response to hypoxia have been investigated by studying specimens of pulmonary and systemic vascular smooth muscle and the isolated pulmonary and systemic circulations. Hypoxia caused a unique and reversible loss of potassium and gain in sodium by pulmonary arterial smooth muscle that did not occur in pulmonary veins or systemic arteries. ...

The present study was designed first to investigate the pulmonary hypertensive effects of chronic hypoxia in spontaneously hypertensive rats and second to compare the cardiovascular effects of atrial natriuretic factor on rats exposed to hypoxia and on control rats kept at sea level. Catheters were placed in the femoral and pulmonary arteries for measurement of mean systemic arterial pressure a...

We recently observed that acute systemic hypoxia produces rapid increases in leukocyte adherence in the mesenteric microcirculation of the anesthetized rat Wood JG, Johnson JS, Mattioli LF, and Gonzalez NC. J Appl Physiol 87: 1734-1740, 1999; Wood JG, Mattioli LF, and Gonzalez NC. J Appl Physiol 87: 873-881, 1999. Hypoxia-induced leukocyte adherence is associated with an increase in reactive ox...

Obstructive sleep apnea is associated with high cardiovascular morbidity and mortality. Intermittent hypoxia of obstructive sleep apnea is implicated in the development and progression of insulin resistance and atherosclerosis, which have been attributed to systemic inflammation. Intermittent hypoxia leads to pro-inflammatory gene up-regulation in cell culture, but the effects of intermittent h...