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Biomedical subjects

L Masana

Publications and source records attributed to L Masana.

At least 91 records · Page 5Linked to original sources
PubMed1986

Lipid peroxidation of low density lipoprotein by human endothelial cells modifies its metabolism in vitro.

Low density lipoprotein (LDL) undergoes qualitative changes when incubated with endothelial cells. Changes in LDL induced by cultured human endothelial cells were associated with release of substances reacting to thiobarbituric acid; they were prevented by addition of EDTA. Modification of LDL by human endothelium, therefore, appears to involve lipid peroxidation. Proneness of LDL to this process was indicated by its occurrence, to a smaller extent, on incubation in the absence of endothelium. Lipid peroxidation of LDL altered its electrophoretic mobility. Modified LDL, but not native LDL, was readily catabolised by human macrophages. Conditioning by human endothelium increased the rate of fractional catabolism of LDL in rabbits. If lipid peroxidation of LDL takes place in vivo it may promote conversion of macrophages to lipid-laden foam cells in the developing atheromatous plaque.

Animals↗
PubMed1985

An alternative procedure for incorporating radiolabelled cholesteryl ester into human plasma lipoproteins in vitro.

A simple method has been developed for labelling human plasma lipoproteins to high specific radioactivity with radioactive cholesteryl esters in vitro. After isolation by preparative ultracentrifugation, the selected lipoprotein was incubated for 30 min at 4 degrees C in human serum (d greater than 1.215) that had been prelabelled with [4-14C]cholesteryl oleate or [1,2-3H]cholesteryl linoleate, and was then re-isolated by ultracentrifugation. All major lipoprotein classes were labelled by the procedure. Specific radioactivities of up to 18 d.p.m. . pmol-1 (46 d.p.m. . ng-1) were achieved. When radiolabelled high-density lipoprotein was infused intravenously, the radioactive cholesteryl ester behaved in vivo indistinguishably from endogenous cholesteryl esters produced by the lecithin (phosphatidylcholine): cholesterol acyltransferase reaction.

Carbon Radioisotopes↗
PubMed1984

Metabolic study of variation in plasma cholesterol level in normal men.

Variation in plasma cholesterol in normal populations underlies a 2-5 fold range of risk of coronary heart disease. The metabolic basis of this variation was studied in a healthy population recruited from a general-practice list. Compared with men in the modal decile of plasma cholesterol, those in the top decile maintained their high levels by overproduction of low-density lipoprotein (LDL). Men in the bottom decile of plasma cholesterol had low levels of LDL, resulting chiefly from a greater rate of fractional catabolism of this lipoprotein; and blood mononuclear cells from men in the bottom decile catabolised LDL more rapidly in vitro than did cells from other men. Intake of dietary lipids by men in the top, modal, and bottom deciles did not differ significantly. Different mechanisms appear to underlie high and low levels of plasma cholesterol in a normal population.

Adult↗
PubMed1982

High-density lipoprotein cholesterol and phospholipids, and apoprotein A in serum of patients with liver disease.

Concentrations of apoprotein A in whole serum, and cholesterol and phospholipids concentrations in the high-density lipoprotein fraction of serum were measured after the precipitation of low-density and very-low-density lipoproteins with sodium phosphotungstate-Mg2+ in 23 patients with liver cirrhosis, 19 patients with extrahepatic biliary obstruction, and 20 healthy control subjects. Patients with cirrhosis and cholestasis showed approximately one-half as much cholesterol and apoprotein A in the nonprecipitable high-density lipoprotein fraction as normal subjects did. High-density lipoprotein phospholipids concentrations in those patients were normal or slightly increased, however, which is about double what one would expect from the apoprotein A and cholesterol content.

Adult↗
PubMed1981

[High density lipoprotein cholesterol. Normal values, influence of vascular risk factors and of a vegetarian diet (author's transl)].

The serum levels of cholesterol bound to high density lipoproteins (HDL-C) were determined by the heparin-manganese chloride precipitation method in 306 subjects, 182 male with ages ranging from 11 to 81 years, and 124 female with ages ranging from 7 to 78 years. Twenty six subjects belonged to a lacto-vegetarian community, while the remaining 280 were healthy volunteers, factory workmen sampled during a regular check-up, and either outpatients or inpatients being evaluated for minor illnesses or minor surgery. None of the subjects had arteriosclerosis or a metabolic disease and, with the exception of the lacto-vegetarians, they were all consuming a normal diet. HDL-C concentrations varied very little among the different age groups. Females had HDL-C values slightly superior to those of males. No significant differences were found between smokers and non-smokers, alcohol drinkers and non-drinkers, and regularly exercising and sedentary people. HDL-C concentrations were independent of total cholesterol and triglyceride levels. Females under oral contraceptive treatment had lower HDL-C levels than control females, but the differences were not statistically significant. Compared with age and sex-matched controls, the lactovegetarians showed similar HDL-C concentrations.

Adolescent↗
PubMed1981

Serum high-density lipoproteins cholesterol, heparin and peripheral vascular disease.

Serum high-density lipoprotein cholesterol (HDL-C) has been determined in 85 patients with peripheral vascular disease (PVD) and in 72 healthy control subjects. HDL-C levels were significantly decreased in patients with PVD. Considering other vascular risk factors as diabetes mellitus, smoking and hypertension, there were no differences in HDL-C levels. Twenty-three patients received heparin as treatment, this subgroup showed a HDL-C levels higher than patients who were not under heparin therapy. The possible clinical implications of these facts are discussed.

Adult↗