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Biomedical subjects

S N Gershoff

Publications and source records attributed to S N Gershoff.

At least 37 records · Page 2Linked to original sources

Nutrition studies in Thailand: effects of calories, nutrient supplements, and health interventions on growth of preschool Thai village children.

A study of the effects of providing high-calorie and vitamin-mineral supplements to preschool village children retarded in growth and development in Chiang Mai, Thailand was done. The preschool children of 24 villages with a population of approximately 11,000 were divided into five control and intervention groups. The interventions consisted of a village health program, high-calorie snacks, and vitamin-mineral supplements. The supplements when used were provided in day care centers for preschool children. The health and nutrition interventions used did not significantly affect growth during the study period reported from December 1981 to October 1983. Monthly changes in length and weight observed in this and a previous study indicate that growth patterns in Thai children are different from those seen in industrialized societies. Factors other than lack of nutrients and infection may be responsible for the inadequate growth often reported in developing countries.

Body Height↗

The relationship between estrogen levels and diets of Caucasian American and Oriental immigrant women.

The relationship between diet and estrogens was studied in two groups of women with different dietary habits and breast cancer risks. Plasma estrogens and androgens and 24-h urinary and fecal excretion of estrogens were measured in premenopausal and postmenopausal Caucasians and recent Oriental immigrants from Southeast Asia to Hawaii. Premenopausal Caucasians had 30-75% higher plasma estrone and estradiol levels than their age-matched cohorts in Hawaii, and the postmenopausal Caucasians had 3-fold higher plasma levels of estradiol. The Oriental women excreted more than twice the amount of estrogen in their feces but they excreted significantly less in their urine. Thus, the ratio of urinary-to-fecal excretion was approximately 3-5 times higher in young Caucasian women. Analysis of dietary components and plasma estrogens in premenopausal women showed a positive correlation between daily intake of total fat and saturated fat and plasma estrone and estradiol concentrations.

Adolescent↗

Subcutaneous fat remodelling in Southeast Asian infants and children.

Longitudinal data on 1,048 Thai children were evaluated for evidence of subcutaneous fat remodelling. Fat distribution, as defined by 100 (triceps/[triceps + subscapular]), was more pronounced in the limbs during infancy but shifted toward the trunk thereafter. Subsequent stepwise regression analysis indicated that biological age--as measured by Gruelich-Pyle bone age--and weight together explained between 0.8% and 14.5% of variance in fat distribution, with generally larger R2 values over age and for males. Relationships were curvilinear, with sex differences in slope. Path analysis supported the model that weight was a major causal agent primarily after infancy, whereas biological age had a small influence both in infancy and in late childhood. These findings indicate that trunk fat deposition is a normal feature of childhood. They also suggest that hypotheses which associate elevated trunk fatness with disorders of glucose metabolism are invalid for younger children.

Adipose Tissue↗

Effects of sugars and vitamin B-6 deficiency on oxalate synthesis in rats.

Rats fed diets containing galactose as the source of carbohydrate excreted greater amounts of endogenously formed oxalic acid in their urine, compared to rats fed glucose, fructose or sucrose. Rats fed lactose showed similar but less marked effects. The greatest amounts of urinary and fecal oxalate excretions were observed among rats fed galactose and no vitamin B-6. This group had the lowest body weights after 3 weeks of feeding. Control rats fed galactose or lactose diets weighed less than those fed sucrose, glucose or fructose diets. All rats fed galactose developed cataracts. More [14C]oxalic acid was recovered in the urine and kidneys of control rats injected with D-[U-14C]galactose compared to those injected with D-[U-14C]glucose or D-[U-14C]fructose. Similar results were observed in kidneys of vitamin B-6-deficient rats. The possible mechanisms by which galactose and other sugars may be converted to oxalate are discussed.

Animals↗

Potentiation of oxygen toxicity in rats by dietary protein or amino acid deficiency.

Rats fed 3% casein diets for 6 days showed an increased susceptibility to greater than 98% oxygen [mean survival time 46.9 +/- 4.1 (SD) h] compared with animals fed 25% casein diets (mean survival time 60 +/- 5 h). The 3% casein diet did not reduce the responses to hyperoxia of lung glucose-6-phosphate dehydrogenase, glutathione peroxidase, and glutathione reductase (NAD(P)H), which maintain tissue levels of reduced glutathione or lung superoxide dismutase levels. While supplementation of the 3% casein diet with the sulfur-containing amino acids (cysteine, cystine, or methionine) prevented the increased oxygen toxicity, supplementation with leucine, a nonsulfur-containing amino acid, had no effect on potentiation of toxicity. Animals fed the unsupplemented 3% casein diet failed to show an elevation of lung glutathione in response to hyperoxia. When the 3% casein diet was supplemented with cysteine, total lung glutathione levels increased normally during oxygen exposure. Supplementation of the 25% protein diet with cysteine did not further protect these animals. We conclude that potentiation of oxygen toxicity by dietary protein deficiency in the rat is due to the low sulfur-containing amino acid content of the diet; the mechanism of increased toxicity by hyperoxia is probably related to an inability to increase glutathione levels due to a shortage of the cysteine component of the glutathione tripeptide.

Amino Acids↗

Factors affecting endogenous oxalate synthesis and its excretion in feces and urine in rats.

It has been observed that the feces as well as urine of rats fed diets supplemented with 3% glycine and 5.2% hydroxyproline contain unexpectedly high amounts of endogenously formed oxalate. That intestinal microorganisms do not synthesize significant amounts of oxalate was indicated by the findings that oral tetracycline had no effect on oxalate excretion and that germ-free rats excreted more oxalate than conventional rats. Since little intraperitoneally injected [14C] oxalate appeared in the feces, and rat intestinal mucosa homogenates were found to produce oxalate from a variety of precursors of which glyoxylic acid was far the most important, it is probable that the intestinal mucosa may be an important source of fecal oxalate observed in these studies. Ninety percent of weanling rats fed complete diets supplemented with glycine and hydroxyproline developed urinary stones in 38 days. It has been concluded that in the treatment of patients with histories of calcium oxalate urolithiasis, more concern than is commonly shown should be directed towards the feeding of diets high in precursors of endogenous oxalate synthesis.

Animals↗

The effects of vitamin A-deficient diets containing lactose in producing bladder calculi and tumors in rats.

This report describes studies in which diets have been developed which when fed to rats commonly result in the formation of primary urinary bladder calculi. The bladder walls of most of these rats but not those without urinary stones were grossly hypertrophied. Microscopic examinations in one of the studies indicated that about a quarter of the bladders containing stones showed histological changes consistent with those characterized as grade I to II transitional cell carcinomas. In all cases animals showing these histological abnormalities consumed vitamin A-deficient diets in which the carbohydrate was supplied mostly by lactose.

Animals↗

Protein and amino acids of breast milk from Thai mothers.

The protein, amino acids, and nonprotein nitrogen of milk samples obtained from Thai mothers over a period of 0 to more than 270 days postpartum were determined. Protein levels decreased from 1.56% during the 1st wk to a low of about 0.6% from 180 to 270 days and then rose to about 0.7%. The amino acid pattern of the milks suggested a number of differences in their composition and those of samples analyzed in other countries. Nonprotein nitrogen varied from 20 to 40% of the total nitrogen of the milk. It has been concluded that the need for supplementation of breast-fed Thai babies may occur earlier than many nutritionists advocate.

Amino Acids↗

Effects of hydroxyproline and vitamin B-6 on oxalate synthesis in rats.

Relationships among dietary hydroxyproline (HP), vitamin B-6 and endogenous oxalate formation have been studied. In the absence of HP, urinary oxalate excretion was greatest among rats fed vitamin B-6-deficient diets. Supplementation of rat diets with 5.2% HP markedly increased the oxalate excretion of rats fed 0, 0.2 or 10 mg of vitamin B-6 per 100 g of diet, the increases being 2-, 19- and 15-fold respectively. The metabolism of several 14C-labeled oxalate precursors was altered in vitamin B-6-deficient rats. The feeding of HP and different levels of vitamin B-6 also altered their metabolism. The feeding of HP to vitamin B-6-deficient rats resulted in a decrease in the amount of 14C-oxalate formed from injected 14C-labeled glycine, glycolate or glyoxylate. In contrast, HP feeding to rats given 0.2 mg of vitamin B-6 per 100 g, resulted in a marked increase in oxalate formation from injected 14C-glycolate, as well as a decrease in respiratory 14CO2 from injected 14C-labeled glycolate and glyoxylate. HP feedings did not significantly alter the metabolism of these two injected compounds to oxalate or CO2 among rats fed the higher level of vitamin B-6, although some elevation of oxalate formation from glycolate was noted. HP feeding reduced the growth rates of all the rats, but growth depression was greatest in the vitamin B-6-deficient group.

Animals↗

Cats and stones.

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Animals↗

Interrelationships in rats among dietary vitamin B6, glycine and hydroxyproline. Effects of oxalate, glyoxylate, glycolate, and glycine on liver enzymes.

Urinary endogenous oxalate was increased by feeding vitamin B6-deficient or control rats with 5.2% hydroxyproline, or 3% glycine plus 5.2% hydroxyproline. The activities of liver lactic dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PD) , malic enzyme (ME), and ATP citrate lyase were decreased in vitamin B6-DEFICIENT RATS, AND THEIR LIVEr G6PD was further decreased by the addition of glycine and hydroxyproline to their diets. Supplementing control diets with the two amino acids decreased the activities of rat liver LDH, G6PD, and ATP citrate lyase. The effects of glycine and hydroxyproline feeding on the enzymes studied did not appear related to alterations in insulin availability. Since in vitamin B6-deficient rats, there are increases in urinary levels of oxalic and glycolic acids, and glycine, and increases in tissue levels of glyoxylic acid and glycine, the effects of these metabolites on the activities of the above mentioned enzymes were measured. Oxalic acid inhibited the activities of LDH, G6PD, and ME. Glyoxylic acid inhibited LDH and ME, but not G6PD. Glycolic acid inhibited G6PD and ME, but not LDH. ATP citrate lyase was not affected by these substances. Glycine had no effect on the enzymes studied. Diets which increased oxalate excretion generally reduced or did not alter liver and kidney levels of oxalate, glycolate, and glyoxylate. However, the feeding of glycine and hydroxyproline increased kidney oxalate, and liver and kidney glyoxylate in vitamin B6-deficient rats.

ATP Citrate (pro-S)-Lyase↗

Studies of the elderly in Boston. I. The effects of iron fortification on moderately anemic peole.

It has been reported that large numbers of elderly Americans are moderately anemic because of iron deficiency anemia. In the present study, information has been obtained concerning blood composition, health, and nutritional habits of 779 people over 60 years of age, institutionalized or free-living in the Boston area. This paper presents the results of their blood examinations. Two hundred twenty-one of the free-living people examined who showed hemoglobin levels between 9 and 12.9 g/dl agreed to participate in an iron fortification study. Two-thirds of them received iron-fortified grain products daily for 6 to 8 months. The rest received the same foods without added iron. At the end of the experimental period a marked increase in hemoglobin levels averaging 1.4 g/dl was observed in both groups. This appeared to be attributable to an undefined intervention effect; no measurable effects attributable to the iron fortification were observed. Three months of daily ferrous sulfate administration to those whose hemoglobin levels remained below 13 g/dl was without effect. Examination of the data obtained suggests that the cause of the moderately low hemoglobin levels initially observed was not occult bleeding or folic acid or iron deficiency.

Aged↗

Effects of vitamin B6 deficiency on liver, kidney, and adipose tissue enzymes associated with carbohydrate and lipid metabolism, and on glucose uptake by rat epididymal adipose tissue.

Adipose tissue and liver from vitamin B6-deficient rats have an increased lipogenic capacity. Whether this phenomenon is accompanied by changes in the activities of certain enzymes involved in the metabolism of carbohydrate and lipid, or by altered transport of glucose into adipocytes, has been studied. Five glycolytic enzymes (hexokinase, phosphoglucose isomerase, phosphofructokinase, aldolase, and pyruvate kinase), two pentose phosphate pathway enzymes (glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase), malic enzyme, and ATP citrate lyase were measured in the epididymal adipose tissue, livers and kidneys of vitamin B6-deficient and control rats. Vitamin B6 deficiency did not significantly affect the glycolytic enzyme levels in the tissues studied, or the dehydrogenases measured in adipose tissue and kidneys. Liver glucose-6-phosphate dehydrogenase, and adipose tissue and liver malic enzyme were significantly lowered in deficient rats compared to ad libitum and pair-fed controls. Adipose tissue and liver ATP citrate lyase activities were also significantly decreased by vitamin B6 deficiency. In the presence of insulin, the uptake of glucose and 3-O-methyl glucose, a non-metabolizable sugar, by fat pads from deficient rats was greater than uptake by fat pads from control rats. These observations suggest that the increased glucose utilization by adipose tissue and liver of vitamin B6-deficient rats is not directly related to changes in the enzymes studied, but in the case of adipose tissue, may be explained, at least in part, by enhanced glucose uptake.

ATP Citrate (pro-S)-Lyase↗

Science--neglected ingredient of nutrition policy. 10th Martha F. Trulson Memorial Lecture.

Programs to alleviate malnutrition in children in developing countries need revision. Intervention field trials in Thailand, Tunisia, and Guatemala, based on amino acid fortification and supplementary vitamins and minerals, have had little effect on children. In fact, it is often a misconception that frank deficiencies are common characteristics of malnutrition in developing countries.Rather, stunted growth--caused by caloric deficiency often in the presence of adequate food supplies--may be the most prevalent form of malnutrition. The situation occurs when the customary staple food--for instance, rice in Thailand--has such a high caloric density that children cannot eat enough food to meet their needs. Knowledge is not vet available on ways to solve this dilemma. Nevertheless nutritionists must come forward and be willing to contribute their knowledge and expertise in the shaping of national and international nutrition policies to improve the healthand well-being of populations.

Aged↗