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Biomedical subjects

M Stampfer

Publications and source records attributed to M Stampfer.

76 records · Page 5Linked to original sources
PubMed1968

Role of the venous system in baroreceptor-mediated reflexes in man.

Although baroreceptor stimulation produced by marked alterations in arterial pressure has been shown to produce reflex changes in venous tone in animals, the effects on venous tone in man of altering arterial pressure within the physiologic range have not been clear. In six subjects, venous tone did not change when mean arterial pressure was raised by 25-40 mm Hg, although heart rate fell reflexly by 40%. Venous tone remained constant in 10 subjects when arterial pressure was lowered. This contrasted to the sustained rise in forearm vascular resistance and the persistent tachycardia that occurred. However, 12 subjects continued to respond to these interventions by transient venoconstriction. To eliminate possible emotional influences on venous tone due to the experimental intervention, venous responses were studied before and during general anesthesia in five of these subjects. In contrast to the response before anesthesia, an equivalent fall in arterial pressure during anesthesia no longer evoked a venoconstrictor response. Venous reactivity and the baroreceptor reflex arc remained intact during anesthesia, since venous tone always rose after a deep inspiration, and tachycardia always accompanied the fall in arterial pressure. It is concluded that changes in arterial pressure in the physiologic range in man do not induce measurable reflex alterations in venous tone, and that the increases sometimes seen with decreases in arterial pressure appear to be due to extraneous psychic factors.

Journal Article↗
PubMedDate not supplied

The epidemiology of coronary heart disease and estrogen replacement in postmenopausal women.

Cardiovascular diseases remain the leading cause of death in American women. Evidence from epidemiological studies indicates that estrogen replacement therapy in postmenopausal women can reduce their risk of coronary heart disease. Current users, in particular, appear to enjoy the most substantial cardiac benefits. It remains possible that the protective effect of estrogen observed in these studies may be due, in part, to bias. Women who use estrogen see a physician regularly, and compliance with estrogen therapy may identify a low-risk group of women. Furthermore, women who choose to use estrogen may lead generally healthier lifestyles than those who do not take such medication. However, adjustment for known cardiac risk factors in many of the large studies had little impact on the results, implying an equivalent risk status for users and nonusers. In addition, both animal and human studies show that estrogen use lowers low-density lipoprotein cholesterol levels, increases high-density lipoprotein cholesterol levels, improves blood flow, and reduces atherosclerosis. The effect of progestin added to estrogen therapy has not been adequately assessed, but initial evidence suggests that it may somewhat attenuate, although not completely eliminate, the benefits of estrogen on cardiovascular disease. Finally, each individual woman differs in her particular risks and benefits, and careful consideration of each woman's unique situation is required; the fear of breast cancer should be considered, together with the knowledge that many interventions are available to reduce the risk of cardiovascular disease.

Coronary Disease↗