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Biomedical subjects

M Epstein

Publications and source records attributed to M Epstein.

At least 379 records · Page 21Linked to original sources
PubMed1970

Metabolic studies of isolated human eccrine sweat glands.

This paper describes a method for isolating and studying the metabolism of human eccrine sweat glands. (a) Electron microscopy of glands which had been isolated and then incubated for an hour revealed no apparent alteration in morphology. (b) Known variation in gland size (male > female > children) was reflected in the relative rates of lactate production. (c) Lactate production was approximately 1.5 nmoles/gland per hr in the absence of glucose and rose to 2.7 at physiological concentrations of glucose (5.6 mmoles/liter). This amount of lactate production agrees well with the amounts found in sweat. (d) Both adrenergic (epinephrine) and cholinergic (methacholine) stimuli increased lactate production. (e) Glycogen depletion was demonstrated during incubation. (f) O(2) consumption was measured and aerobic metabolism was found to account for less than 1% of the energy derived from anaerobic pathways. These studies demonstrate that the large amounts of lactate appearing in human eccrine sweat can be accounted for by glandular metabolism and that both glycogen and glucose can be used as substrates.

Age Factors↗
PubMedDate not supplied

Efficacy and safety of an over-the-counter transdermal nicotine patch as an aid for smoking cessation.

OBJECTIVE: To evaluate the efficacy and safety of a transdermal nicotine patch as an aid for smoking cessation in an over-the-counter setting. DESIGN: Multicenter, double-blind, randomized, placebo-controlled trial of 6-week duration with 18 weeks of follow-up. SETTING: Four shopping mall precincts. PARTICIPANTS: The randomized sample consisted of 802 adults (mean age, 39 years) and was 89% white and 54% female. A smoking history of at least 20 cigarettes per day for 1 year and a score of 5 (on a 10-point scale) on a motivational assessment questionnaire were required for enrollment. Poststudy follow-up was limited to those who had quit smoking at the end of 6 weeks. INTERVENTION: Nicotine patches were provided at the shopping mall. Guidance consisted only of package instructions and a smoking cessation self-help booklet. MAIN OUTCOME MEASURES: Quit rates were defined as total abstinence from smoking for 4 consecutive weeks (treatment weeks 3-6), point prevalence smoking status at week 6, or nonsmoker at week 6 and week 24 (6-month postquit date). Smoking status was assessed by diaries, and verification for the first 2 quit rates was obtained by confirmation of carbon monoxide of 8 ppm or less in expired breath. Safety was evaluated by self-reported adverse events. RESULTS: Quit rate was 12% for the active treatment group and 5.5% for the placebo group, based on total abstinence for 4 consecutive weeks (P = .001) compared with quit rates of 19.5% and 7.5% for active treatment and placebo groups, respectively, based on point prevalence data at week 6. At 24 weeks, 8.2% of nonsmokers in the active treatment group and 4.0% in the placebo group remained nonsmokers. At least 1 adverse event was reported by 57% receiving the nicotine patch and 39% receiving placebo (P<.001). CONCLUSIONS: When the nicotine patch was used in an over-the-counter setting, quit rates were comparable to those reported for medical settings. A 2:1 quit rate advantage was achieved at week 6 and was maintained at 24 weeks.

Administration, Cutaneous↗
PubMedDate not supplied

Renal eicosanoids as determinants of renal function in liver disease.

The available data suggest that alterations in renal prostaglandin metabolism participate in the pathogenesis of at least two prominent renal complications of liver disease: (a) sodium retention and (b) HRS. Although the data are highly suggestive, additional studies, including experimental manipulations that augment vasodilatory prostaglandins while diminishing vasoconstrictor metabolites of arachidonic acid, will be required to establish the role of prostaglandins or other arachidonic acid metabolites in mediating these renal abnormalities. The clinical caveat emerging from these observations is that every attempt should be made to avoid prescribing drugs which possess cyclooxygenase inhibitory activity to patients with decompensated liver disease who are sodium-avid.

Animals↗
PubMedDate not supplied

Peripheral arterial vasodilation hypothesis: a proposal for the initiation of renal sodium and water retention in cirrhosis.

Renal sodium and water retention and plasma volume expansion have been shown to precede ascites formation in experimental cirrhosis. The classical "underfilling" theory, in which ascites formation causes hypovolemia and initiates secondary renal sodium and water retention, thus seems unlikely. While the occurrence of primary renal sodium and water retention and plasma volume expansion prior to ascites formation favors the "overflow" hypothesis, the stimulation of the renin-angiotensin-aldosterone system, vasopressin release and sympathetic nervous system associated with cirrhosis is not consonant with primary volume expansion. In this present article, the "Peripheral Arterial Vasodilation Hypothesis" is proposed as the initiator of sodium and water retention in cirrhosis. Peripheral arterial vasodilation is one of the earliest observations in the cirrhotic patient and experimental animals with cirrhosis. Arterial vasodilators and arteriovenous fistula are other examples in which renal sodium and water retention occur secondary to a decreased filling of the arterial vascular tree. An increase in cardiac output and hormonal stimulation are common features of cirrhosis, arteriovenous fistula and drug-induced peripheral arterial vasodilation. However, a predilection for the retained sodium and water to transudate into the abdominal cavity occurs with cirrhosis because of the presence of portal hypertension. The Peripheral Arterial Vasodilation Hypothesis also explains the continuum from compensated to decompensated cirrhosis to the hepatorenal syndrome.

Animals↗
PubMedDate not supplied

Evaluation of the appropriateness of blood and blood product transfusion using preset criteria.

The use of 1930 units of blood or blood products during 765 transfusion episodes in 560 patients was reviewed. This represented one-half of all transfusions in a large medical center over a 2-month period. By clearly defined, present criteria, 42.3 percent of the episodes were found not to be appropriate. Whole blood and platelet transfusions were used more appropriately than those of red cells, cryoprecipitate, and fresh-frozen plasma. Blood transfusions were used more appropriately in the management of acute bleeding or anemia associated with cardiovascular problems. Three groups of patients were especially prone to inappropriate transfusions: those with end-stage renal disease or terminal cancer and cancer patients on chemotherapy. Age, sex, and specific hospital wards were not associated with inappropriate use. Most unjustified episodes occurred as a result of the overestimation of the immediate risk incurred by withholding transfusion.

Acute Disease↗