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Biomedical subjects

M el Lozy

Publications and source records attributed to M el Lozy.

17 recordsLinked to original sources
PubMed1985

Diet and 20-year mortality from coronary heart disease. The Ireland-Boston Diet-Heart Study.

In a prospective epidemiologic study of 1001 middle-aged men, we examined the relation between dietary information collected approximately 20 years ago and subsequent mortality from coronary heart disease. The men were initially enrolled in three cohorts: one of men born and living in Ireland, another of those born in Ireland who had emigrated to Boston, and the third of those born in the Boston area of Irish immigrants. There were no differences in mortality from coronary heart disease among the three cohorts. In within-population analyses, those who died of coronary heart disease had higher Keys (P = 0.06) and modified Hegsted (P = 0.02) dietary scores than did those who did not (a high score indicates a high intake of saturated fatty acids and cholesterol and a relatively low intake of polyunsaturated fatty acids). These associations were significant (P = 0.03 for the Keys and P = 0.04 for the modified Hegsted scores) after adjustment for other risk factors for coronary heart disease. Fiber intake (P = 0.04) and a vegetable-foods score, which rose with increased intake of fiber, vegetable protein, and starch (P = 0.02), were lower among those who died from coronary heart disease, though not significantly so after adjustment for other risk factors. A higher Keys score carried an increased risk of coronary heart disease (relative risk, 1.60), and a higher fiber intake carried a decreased risk (relative risk, 0.57). Overall, these results tend to support the hypothesis that diet is related, albeit weakly, to the development of coronary heart disease.

Adult↗
PubMed1983

Dietary variability and its impact on nutritional epidemiology.

Dietary intakes are subject to measurement errors and to day-to-day variation, which have contributed to obscuring the suspected relation between dietary lipids and ischemic heart disease. The effect of measurement error on the correlation between dietary intakes and serum cholesterol levels has been studied by others. In this paper we study the effects of errors on the categorization of subjects according to the quantities of their intakes, and the effects of this misclassification on the observed relation between observed dietary intakes and disease. Our model is based on a bivariate normal joint distribution of true and observed intakes, from which various conditional probabilities can be calculated. Tables are given to simplify many of these computations. We conclude that the usual period of collection of dietary records, 1 week, is usually adequate. The model developed is applicable to any measurement recorded with error, and two examples of its application to the classification of subjects as normotensive or hypertensive are given. The model does depend on a large number of assumptions, some of which are clearly not met. Hence the actual numerical values obtained should be treated with some scepticism. If, however, the assumptions are approximately met, then the results should be reasonable approximations to the truth.

Cholesterol↗
PubMed1979

Effects of vagotomy with and without pyloroplasty on weight and food intake in rats.

Bilateral truncal vagotomy performed in 13 rats reduced weight gain by 26% compared to controls, but also produced gastric distension. Addition of pyloroplasty was found to facilitate gastric drainage in vagotomized rats, and both procedures were then performed in 57 rats of both sexes and varying initial weights. When fed ad libitum, vagotomized animals maintained a weight 14-30% less than controls over periods of 30-300 days. When pair fed, normal rats and rats with vagotomy and pyloroplasty weighed the same. Various partial vagotomies had no effect on weight gain. It was concluded that vagotomy reduces weight gain in rats, that the reduction is the result of decreased food intake, and that the effect of vagotomy is probably not due to gastric distension.

Animals↗
PubMed1978

A critical analysis of the double and triple logistic growth curves.

Recently a model of human growth from the age of one year to maturity, based on two logistic terms, has been proposed. The originators of the model claim that it provides biologically meaningful parameters, and allows total growth to be partitioned into a pre-pubertal and an adolescent component. More recently, they have suggested an improved model, with three logistic terms, which gives a better fit. While the double logistic model gives an adequate fit to the observed height curve, differentiating it leads to a height velocity curve which differs considerably from the observed velocity curve. The triple logistic model gives an excellent fit to both the attained height and height velocity curves. Both models, however, imply a considerable time interval during which both the pre-pubertal and adolescent components are simultaneously contributing to growth, a situation that is difficult to justify biologically. The double model should therefore be discarded, and the triple logistic model considered to be of descriptive, rather than of interpretative, value.

Adolescent↗
PubMed1977

Hypercholesterolemia and triglyceride secretion rates in monkeys fed different dietary fats.

The influence of hypercholesterolemia on the triglyceride secretion rate was studied in both squirrel and cebus monkeys fed coconut oil, corn oil, or safflower oil. The triglyceride secretion rate (TGSR) was determined in vivo following the administration of Triton WR1339, which blocks the clearance of very low density lipoprotein (VLDL). Thus, the increase observed in circulating triglyceride after Triton administration presumably reflecte hepatic triglyceride (VLDL) secretion in the fasted state. The VLDL-TGSR was lowest in hypercholesterolemic monkeys and highest in those fed unsaturated fat diets and having a low serum cholesterol. In all instances, TGSR was inversely correlated with the plasma cholesterol concentration. While a definitive explanation for these observations must await further investigation, the possibility that circulating low density lipoprotein (LDL) acts to feed back on VLDL secretion is discussed. The decreased TGSR associated with the diet-induced cholesterolemia also implies clearance of VLDL is impaired under these conditions.

Animals↗
PubMed1976

Malnutrition studies in Macaca mulatta. V. Effect on biochemical and cytochemical composition of major organs.

The effects of control, dilute, and low-protein duets on organ development were evaluated in infant rhesus monkeys. Both experimental duets resulted in growth failure of the cerebral hemisphere, lung, liver, kidney, and muscle and, with few exceptions, in their total organ contents of water, protein, lipid, glycogen, DNA, and RNA. Calculation of the various ratios for biochemical indices per mg of DNA indicates that with the exception of increased glycogen:DNA ratios in lung of animals fed the dilute diet, increased lipid:DNA ratios in liver, and reduced glycogen:DNA ratios in muscle of animals fed the low-protein diet, all other biochemical profiles of the cellular populations of organs were comparable to control values. Accordingly, the small organ size and reduced organ content of the various biochemical indices of growth appear primarily due to the reduced cellular populations of these organs. The reduced cellular populations reflect failure of the normal miotic processes of infancy to occur, with or without loss of cells already present at the onset of the malnutrition phase. If no cell loss is involved, it is speculated that normal indices of organ growth may still be possible through the processes of "catch up" growth which accompany nutritional rehabilitation.

Age Factors↗
PubMed1976

Effect of dietary fat on hepatic metabolism of 14C-oleic acid and very low density lipoprotein triglyceride in the gerbil.

In order to compare in vitro and in vivo aspects of lipid metabolism and lipoprotein secretion associated with the hyperlipemia of saturated fat feeding, gerbils were fed a diet containing 15% coconut oil or safflower oil for 6 weeks. In vitro incorporation of fatty acid was determined by measuring 14C-oleic acid incorporation into hepatic lipis in liver fasting gerbils following Triton WR1339 injection. The plasma lipoprotein profile was assessed by agarose electrophoresis. Coconut oil produced a hypertriglyceridemia and hypercholesterolemia associated with the appearance of very low density migrating lipoprotein, not seen with the safflower oil. Coconut oil also increased the hepatic triglyceride content, enhanced 14C-oleic acid incorporation into total lipid, and favored fatty acid incorporation into triglyceride; safflower oil facilitated esterification of oleic acid into phospholipid. Triton blockade of gerbils fed safflower oil resulted in twice the triglyceride secretion rate of those fed coconut oil. Our interpretation of the data is that dietary polyunsaturated fat favors incorporation of fatty acids into phospholipid, enhances both triglyceride secretion and the plasma transport and clearance of triglyceride and cholesterol and that the hyperlipemia of coconut oil feeding reflects a reduced metabolic clearnace of circulating lipid associated with that dietary fat.

Animals↗
PubMed1975

Amino acid composition of the diet in a region of Southern Tunisia.

As part of a study of the effects of lysine supplementation of wheat products in Southern Tunisia one qualitative and four quantitative surveys of food consumption were carried out. The average diet provided 7.1 MJ (1,670 kcal), 42 g of protein and 1,280 mg of lysine per person per day. The overall dietary protein thus supplied only 31 mg of lysine/g of protein, or about 56% of the level recommended by the FAO/WHO Expert Committee on Protein Requirements. Addition of lysine to all wheat products to a final effective concentration of 0.2% would raise the dietary lysine level to 45 mg/g protein, or 82% of the FAO/WHO recommended level, at which time threonine would become limiting. Irrespective of whether the FAO/WHO pattern of 1973, breast milk, cow's milk, whole egg or a modification of the FAO pattern of 1957 was used to assess the quality of the protein in the diet, lysine was the first, and threonine the second limiting amino acid (except in comparison with breast milk, which showed tryptophan as the second limiting amino acid). In no case did there appear to be any problem with the sulfur-containing amino acids.

Adolescent↗
PubMed1975

Malnutrition studies in Macaca mulatta. IV. Energy and protein consumption during growth failure and "catch-up" growth.

Infant rhesus monkeys were fed either a control, dilute or low protein diet from 1 to 7 months of age, and the control diet from age 7 to 12 months. All diets were fed ad libitum. Curves were fitted for energy and protein consumption and for growth in weight, length and head circumference. Both experimental groups developed increasing deficits of energy and protein consumption during the undernutrition experiment. With nutritional rehabilitation, the animals previously fed the dilute diet immediately increased their consumption of energy and protein to levels appropriate for age. Those previously fed the low protein diet showed an increased nutrient uptake, but one more appropriate for size peers. Reduced growth velocity occurred with both experimental diets. "Catch-up" growth, and growth velocity per unit diet energy and protein was most obvious for body weight, but recovery from growth deficits was most complete for growth in head circumference. Nutrient deficits accumulated by animals fed the dilute diet were not recovered during catch-up growth; catch-up growth occurred in animals previously fed the low protein diet even though cumulative nutrient deficits were increasing.

Animals↗
PubMed1975

Nutritional correlates of child development in southern Tunisia. IV. The relation of deciduous dental eruption to somatic development.

Deciduous dental eruption in a group of 658 children below 3 years of age in Southern Tunisia was found to be correlated with the general somatic development. On the other hand, this association was less close than that among the different components of somatic growth, suggesting that dental eruption is less affected by the factors which delay somatic growth in that area. Attempts were made to obtain methods of estimating the ages of children using the number of erupted deciduous teeth, both by means of regression equations and by a table of the median age of children with different numbers of pairs of teeth. In both cases the estimates obtainable are not accurate enough to do more than divide the children into coarse age groups. It is concluded that in anthropometric work there is no substitute for accurately known chronological ages.

Age Determination by Teeth↗