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Biomedical subjects

S Margen

Publications and source records attributed to S Margen.

At least 55 records · Page 3Linked to original sources
PubMed1978

Absorption of mono- and polyglutamyl folates in zinc-depleted man.

The effect of experimental zinc depletion on the intestinal absorption of mono- and polyglutamyl folates was assessed in six healthy male subjects by measuring the increase in serum folate after an oral dose of pteroylmonoglutamate and pteroylheptaglutamate before and after initiation of a zinc-deficient diet. At the beginning of the study, no differences were detected in the absorption of pteroylmono- and heptaglutamate. After zinc depletion, the rise in serum folate after an oral dose of pteroylheptaglutamate was reduced by an average of 53% while pteroylmonoglutamate absorption appeared to be unchanged. These data suggest that zinc depletion results in a decreased intestinal hydrolysis of pteroylpolyglutamate and that intestinal conjugase in man is a zinc-dependent enzyme.

Adult↗
PubMed1978

Lactation and pregnancy in Iran. II. Diet and nutritional status.

Dietary intake in the third month postpartum and nutritional status during pregnancy close to term were assessed in Iranian urban uomen of low and middle socioeconomic status as part of a study investigating nutrition, hormonal status, and lactation in a population where lactation failure is a serious problem. Dietary intake was assessed by the 24-hr-recall method. The greatest differential in food groups consumed was in animal products, fruit, and vegetables. Intake of nutrients equal to or less than 80% of recommendations in both socioeconomic groups were energy, vitamin B6, folacin, calcium, iron, and zinc. In the low socio-economic group, only average intakes of vitamin C, thiamin and protein met the standards. Significant differences were found between the socioeconomic groups in hemoglobin, hematocrit, serum total protein, and protein fractions, but not in weight and height. The only parameters of nutritional status significantly correlated with adequacy of lactation were postpartum weight and percent of standard weight for height in the low socioeconomic group, and hematocrit values in the middle socioeconomic group. Differences between pregnant and postpartum individual values of the blood parameters were in general greater in the middle socioeconomic group than the low socioeconomic group.

Blood Cells↗
PubMed1978

Absorption of stable isotopes of iron, copper, and zinc during oral contraceptives use.

The absorption of iron, copper, and zinc was determined in 22 women 19 to 25 years of age from the difference between intake and fecal output of the stable isotopes 58Fe, 65Cu, and 70Zn, as measured by neutron activation analysis. Of the 22 women, 14 were using oral contraceptive agents, and the other eight were not. Absorption in the group using oral contraceptive agents did not differ significantly from the group not using oral contraceptive agents. The overall iron absorption averaged 14%, copper 57%, and zinc 38%.

Adult↗
PubMed1978

Growth hormone response to arginine infusion in malnourished children.

Pituitary response to stimulation was assessed by intravenous arginine infusion in 17 malnourished children and 7 controls. Following stimulation, serum growth hormone levels increased from 6.6 +/- 1.2 to 14.9 +/- 2.9 ng/ml in the marasmic group and similarly from 7.3 +/- 1.8 to 11.9 +/- 2.7 ng/ml in the controls. By contrast, in kwashiorkor the mean growth concentration was high and remained unchanged (19.6 +/- 3.9 ng/ml before and 17.2 +/- 2.1 ng/ml after stimulation). No difference was observed between groups for serum insulin concentration. These results do not lend support to the suggestion that there might be atrophy or pituitary hypofunction in infantile malnutrition.

Arginine↗
PubMed1977

Effect of low zinc intake and oral contraceptive agents on nitrogen utilization and clinical findings in young women.

In a previous paper we reported that serum, urine and fecal zinc levels fell markedly in women taking a combination oral contraceptive agent (+OCA) and in women with normal menstrual cycles (-OCA) when they consumed a low-zinc diet (less than 0.2 mg/day) for 35 days. We evaluated other biochemical and clinical data in order to determine if depletion of accessible body zinc and/or physiologic adjustment to conserve body zinc stores had occurred. Neither low zinc intake nor oral contraceptive use appeared to influence nitrogen balance or body weight. Use of contraceptive drugs appeared to influence the response of blood parameters to zinc depletion. Serum transferrin and cholesterol declined significantly in the -OCA group, whereas alkaline phosphatase and gamma-globulin changed significantly in both groups. Clinical problems developed in all the subjects with serum zinc levels below 50 microgram/dl during the study; three of the six with serum zinc levels above 50 microgram/dl also complained of clinical symptoms. The results suggest that zinc deficiency through depletion of accessible body zinc stores developed during the 35-day study.

Blood Cells↗
PubMed1977

Zinc excretion in young women on low zinc intakes and oral contraceptive agents.

Zinc excretion under conditions of negligible zinc intake (0.17 mg/day) was measured in women taking a combination oral contraceptive agent (+OCA) and in women with normal menstrual cycles (-OCA). A semipurified, constant formula diet, providing negligible amounts of zinc, copper and iron, but adequate levels of other essential nutrients, was fed. During the 35--day study, serum and urinary zinc declined more markedly in the +OCA than -OCA groups. Serum zinc dropped 47% in the +OCA and 21% in the -OCA; urinary zinc declined 83% and 62% in the two groups. After pre-study, zinc was cleared from the gut, fecal zinc decreased about 40% in both groups. Whole body integumental zinc losses were similar for both groups, about 0.7 mg/day. For -OCA, zinc losses via this route were higher during the luteal phase than during menstruation. Menstrual fluid zinc contents were negligible and similar for both groups, about 5 microgram/day. The data suggest that accessible zinc stores are not extensive and that depletion of these stores, as a result of the low-zinc diet, caused the fall in serum zinc. The use of OCA influenced the response to the low-zinc diet, but endogenous zinc losses calculated for day 1 were nearly the same for both groups, about 1.6 mg/day.

Adolescent↗
PubMed1976

Wine versus ethanol in human nutrition. I. Nitrogen and calorie balance.

There are implications in the literature that wine is different from other alcoholic beverages and that it may even have a beneficial effect on the nutritional process. A metabolic study was undertaken in an attempt to document the effects of wine versus ethanol on absorption of various nutrients. Nitrogen and caloric data are presented here. During each of four 18-day experimental periods, six healthy, young men were given, in random order, a liter per day of the following test beverages: Zinfandel wine (9.3% w/v alcohol); dealcoholized Zinfandel wine; pure ethanol (9.3% w/v aqueous alcohol solution); and deionized water. These beverages were divided into four equal feedings and administered with a carefully controlled isocaloric diet over a 12-hr period. The subjects tended to lose weight on alcohol-containing regimens, suggesting that calories from alcohol may not be as efficient as those from fat and carbohydrate. Urinary excretion of nitrogen was significantly greater during wine and ethanol administration than during feeding of the other test beverages. This was reflected in an increase in uric acid and urea nitrogen output, primarily, the latter, suggesting that alcohol may directly affect protein catabolism. There was no significant difference in fecal nitrogen excretion between experimental periods.

Adult↗
PubMed1975

Effect of oral contraceptive agents on the metabolism of some trace minerals.

Biochemical and metabolic alterations noted in women taking the oral contraceptive agents have included changes in blood levels of some trace minerals. Only a few of these, namely, iron, copper and zinc, have been studied. This paper intends to review the changes reported and outline the beginning of a series of studies to attempt to determine whether there is any metabolic significance to these alterations. The alterations reported in blood levels are generally believed to be related in large measure to alterations in levels of specific "transport" proteins induced primarily by estrogen. The significance of these changes is generally unknown, however, they involve slight elevations in serum iron and copper and possibly a reduction in serum zinc, although these are not as clear-cut as those of the other two trace minerals. In an attempt to determine whether any metabolic significance could be attributed to these changes, several studies have been instituted. The first, reported in this paper, consisted of a metabolic study on a group of seven women aged 18-32 who had been taking oral contraceptives for at least 3 years. The subjects were studied over four metabolic periods for a total length of 116 days. They were studied in a random fashion, generally 2 months on and 2 months off the pill, although this varied slightly. The subjects were fed a controlled formula diet throughout this study and vitamins and trace minerals, other than copper, iron and zinc, were given orally in capsules. A trace mineral solution was administered so that the total daily iron, copper and zinc could be fed in four equal feedings per day with the formula. Measurements consisted of studies of the blood levels of the trace minerals as well as their binding proteins, various indices of blood chemistry to assess health, hematological indices and total balance studies for each of the trace minerals and nitrogen. The balance studies included not only urine and fecal loss but also skin, menstrual and hair losers. Preliminary results are discussed as well as the formidable problems involved in trace mineral studies in humans. These problems are not only related to contamination but also are analytic in nature.

Adolescent↗
PubMed1975

Studies in calcium metabolism. II. Effects of low calcium and variable protein intake on human calcium metabolism.

Six healthy males consumed diets containing about 0.1 g calcium/day at three levels of protein intake: 0.9, 12, and 24 g nitrogen/day. Daily urinary calcium excretion on the 0.9 nitrogen diet was 51 mg, 99 mg on the 12 g nitrogen diet, and 161 mg on the 24 g nitrogen diet. A calcium supplement of 0.9 g for four subjects on the 12 g nitrogen diet caused an increase in urinary calcium from 68 to 160 mg/day. Varying the calcium and protein intake had no effect on dermal calcium loss or serum calcium. Five subjects had the least negative calcium balance on the 12 g nitrogen diet. Increase in urinary calcium is not likely to result solely from enhancement of intestinal calcium absorption. Our data suggest that increased glomerular filtration with possible inhibition of renal tubular reabsorption of calcium may be an additional mechanism responsible for the calciuretic effect during high-protein intake.

Adult↗