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Biomedical subjects

R I Levy

Publications and source records attributed to R I Levy.

At least 55 records · Page 3Linked to original sources
PubMed1981

The effects of low cholesterol, high polyunsaturated fat, and low fat diets on plasma lipid and lipoprotein cholesterol levels in normal and hypercholesterolemic subjects.

The effects of various cholesterol-lowering diets on plasma lipid and lipoprotein cholesterol levels were assessed in normal and hypercholesterolemic subjects. The base-line diet was an ad libitum hospital diet of normal composition. Diet A was a 20% protein, 40% carbohydrate, 40% fat, polyunsaturated:saturated fat ratio 0.1 to 0.3, 250 to 300 mg cholesterol diet, diet B was identical to diet A except that the polyunsaturated/saturated fat ratio was 1.8 to 2.2, and diet C was a 20% protein, 80% carbohydrate, very low fat (5 to 10 g), polyunsaturated/saturated fat ratio 0.1 to 0.3, 150 to 200 mg cholesterol diet. Diet A (low cholesterol) caused mean reductions in plasma, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol of 5.9, 5.6, and 6.3%, respectively, in 11 normal subjects. Diet B (low cholesterol, high polyunsaturated fat) caused significant decreases in plasma cholesterol, LDL cholesterol and HDL cholesterol of 17.0, 16.2, and 17.4%, respectively, in 12 normal subjects; and reductions of 11.0, 10.8, and 17.1%, respectively, in 19 hypercholesterolemic subjects. Diet C (low cholesterol, very low fat) produced significant mean decreases in plasma, LDL, and HDL cholesterol of 26.7, 29.9, and 27.9%, respectively, in 11 normal subjects, and in nine hypercholesterolemic patients of 22.6, 27.2, and 28.6%, respectively. The reductions in plasma cholesterol caused by these diets were therefore due to decreases in both LDL and HDL cholesterol with no significant changes in the LDL cholesterol:HDL cholesterol ratio.

Adult↗
PubMed1980

Changes in plasma lipids and lipoproteins after a modified fat diet.

20 male and female patients with type II hyperlipoproteinaemia and 10 normal male and female subjects were fed for 11--15 days a eucaloric diet containing less than 300 mg cholesterol with a polyunsaturated to saturated fatty-acid ratio of about 2.0. Male subjects and patients and female patients showed statistically significant decreases in plasma total cholesterol and low-density lipoprotein (LDL) cholesterol levels; the change in LDL-cholesterol was not significant in female subjects. The changes in lipid and lipoprotein levels in patients were greater than those in subjects, (except for the changes in high-density lipoprotein (HDL) in women, which were similar), which suggested that the magnitude of change depended on initial levels. This difference was not present when the data were evaluated as percent change. Mean levels of HDL-cholesterol decreased in both patients and subjects. However, the proportion of total cholesterol contributed by HDL and LDL, and hence the HDL/LDL ratio, was unchanged from pre-diet levels.

Adult↗
PubMed1980

The structure, function and metabolism of high-density lipoproteins: A status report.

Case-control and prospective epidemiologic studies have found a striking, consistently negative association between high-density lipoprotein (HDL) levels and coronary vascular events. As a result, the genetic and environmental determinants of HDL levels are being studied intensively. These investigations and their potential clinical applications require a fundamental understanding of the structure, function and metabolism of HDL and its components. Of special interest are the means by which HDL exerts its apparently protective effect. In this report we characterize the structure of HDL and describe its components, particularly the protein component. We discuss HDL metabolism in light of the relationship of HDL to the other lipoprotein classes, and relate what little is known of the functions of HDL. We also review the biochemical mechanisms by which HDL may protect against cardiovascular disease and discuss further biochemical research that will be necessary for a better understanding of HDL.

Apolipoproteins↗