Biomedical subjects
Publications and source records attributed to J T Reeves.
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We have investigated the effects of chronic oral administration of two anorectic substances, fenfluramine and aminorex, especially on the pulmonary circulation in young pigs with one ligated pulmonary artery. The pulmonary vascular reactivity was tested by alveolar hypoxia, alveolar hyperoxia and infusion of prostaglandin F2ALPHA. No elevation of pulmonary arterial pressures or resistances were found due to the intake of fenfluramine or aminorex over a three month period. The responses to the vasoconstrictor stimuli, hypoxia and prostaglandin F2alpha, and to the vasodilator stimulus, hyperoxia, were equal and not augmented in the drug groups. Fenfluramine or aminorex could therefore could therefore not be shown to have an adverse effect on the pulmonary circulation or on the reactivity of the pulmonary vascular bed in the pig, but fenfluramine elevated systemic arterial pressure.
To examine the relationship between cardiac filling pressures during exercise in man and oxygen transport, we examined sea level data from Operation Everest II. The results showed that, (1) both right atrial and wedge pressures rose with heavy exercise in normal man, (2) the magnitude of the rise in these filling pressures related both to stroke volume and maximum exercise capacity, (3) wedge pressure was tightly coupled to right atrial pressure, with each mm Hg increase in right atrial pressure resulting in a 1.4 mm Hg increase in wedge pressure, and (4) very high wedge pressures occurred (in some subjects greater than 30 mm Hg), which contributed to an elevation of pulmonary arterial pressure. Thus direct measurements indicate right heart filling pressure increases with exertion in normal man, probably providing the necessary right heart output to fill the left heart. We speculated that the high cardiac filling pressures might be needed to maintain oxygen transport during heavy exercise, and that such pressures could contribute both to elevated pulmonary arterial pressure and to increased filtration of water into the lung.
An examination of recent Colorado vital statistics records was performed. The records included 194,526 live births and 3,100 infant deaths occurring during the years 1969-73, and some 466,000 live births and 71,000 infant deaths occurring during 1960-71. Birth weights at high altitude (2,744 to 3,100 m) were found to be reduced owing to retardation of intrauterine growth rather than preterm delivery. Despite decreased infant mortality at all altitudes in Colorado during the last 20 years, the infant mortality rate at high altitude remains almost twice that seen in Denver. The elevated mortaltiy at high altitude occurred within 28 days after birth, primarily in preterm (less than 38 weeks) infants. It appears that high altitude, possibly throuth the mechansif of exaggerated fetal hypoxia, retards fetal growth and increases the mortality rate of preterm infants.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.