A rapid micromethod for apolipoprotein E phenotyping directly in serum

A new method for the apolipoprotein E phenotyping has been developed. The method is based on isoelectric focusing of either delipidated or guanidine-HCl-treated serum or plasma in a horizontal slab gel system followed by immunoblotting using either polyclonal or monoclonal anti-apolipoprotein E antibodies as first antibody. Apolipoprotein E...

Effect of low-dose oral contraceptives on lipoproteins and lipolytic enzymes: Differences between two commonly used preparations

Changes in circulating lipoproteins, which may be related to the risk for atherosclerotic vascular disease, were studied in a control group and in two groups of 24 or 26 women using different preparations of low-dose oral contraceptives for 3 months. One preparation contained 150 μg levo-norgestrel and 30 μg ethinylestradiol (Stediril-d 150/30);...

In vitro studies on origin and site of action of enzyme activity responsible for conversion of human proapoprotein A-I into apoprotein A-I

Human hepatocellular carcinoma cells (Hep G2) were shown to secrete apo A-I as a proprotein. No apo A-I synthesis could be detected with endothelial cells from human umbilical cord veins. Conversion of proapo A-I into apo A-I is a slow (of the order of hours) process, mediated by a Ca2+/Mg2+-dependent enzyme which is present on the surface of...

Immunoelectronmicroscopy of the binding of high density lipoprotein apoproteins to normal and hypercholesterolemic human fibroblasts

We visualized the apolipoproteins of high density lipoproteins (HDL) that were bound to cultured human fibroblasts at the ultrastructural level, with an immunoenzymecytochemical method. By using antisera against (a) apolipoprotein AI (a major apolipoprotein of HDL) and (b) apolipoprotein E (an apolipoprotein present in HDL), the binding of HDL...

Suppression of cholesterol synthesis in cultured fibroblasts from a patient with homozygous familial hypercholesterolemia by her own low density lipoprotein density fraction. A possible role of apolipoprotein E

The suppression of cellular cholesterol synthesis by low density lipoprotein (LDL) from a normal and from a homozygous familial hypercholesterolemic subject was measured on normal fibroblasts and on fibroblasts derived from the same homozygous familial hypercholesterolemic patient. On normal fibroblasts both LDL preparations (density 1.019 to 1...

Lipoprotein secretion by isolated rat hepatocytes: Characterization of the lipid-carrying particles and modulation of their release

Lipoprotein production by freshly isolated rat hepatocytes in suspension was studied during short (1-3 hr) incubation periods. The heaptocytes release very low density (91.10 g/ml). These particles with higher densities have not been positively identified; the latter group is dissimilar to the high density lipoprotein, which occurs in rat liver...