We describe a simplified method for measuring high-density lipoprotein cholesterol in serum after very-low- and low-density lipoproteins have been precipitated from the specimen with sodium phosphotungstate and Mg2+. Values so obtained correlate well with values obtained with the heparin-Mn2+ precipitation technique (r = 0.95, CV less than 5% in 66% of the subjects studied and between 5 and 10% in the remaining ones) or by ultracentrifugal separation (r = 0.82, CV less than 5% in 80% of the subjects studied and between 5 and 10% in the remaining ones). Our precipitation technique is more appropriate for routine clinical laboratory use.

Cholesterol determination in high-density lipoproteins separated by three different methods.

A comprehensive evaluation of the heparin-manganese precipitation procedure for estimating high density lipoprotein cholesterol.

The Tromso Heart-study. High-density lipoprotein and coronary heart-disease: a prospective case-control study.

Background Insulin resistance and hyperinsulinemia are features of obesity, non-insulin-dependent diabetes mellitus, and other disorders. Skeletal muscle is a major site of insulin action, and insulin sensitivity may be related to the fatty-acid composition of the phospholipids within the muscle membranes involved in the action of insulin. Methods We determined the relation between the fatty-acid composition of skeletal-muscle phospholipids and insulin sensitivity in two groups of subjects. In one study, we obtained samples of the rectus abdominis muscle from 27 patients undergoing coronary artery surgery; fasting serum insulin levels provided an index of insulin sensitivity. In the second study, a biopsy of the vastus lateralis muscle was performed in 13 normal men, and insulin sensitivity was assessed by euglycemic-clamp studies. Results In the patients undergoing surgery, the fasting serum insulin concentration (a measure of insulin resistance) was negatively correlated with the percentage of individua...

The Relation between Insulin Sensitivity and the Fatty-Acid Composition of Skeletal-Muscle Phospholipids

Separation and quantitation of subclasses of human plasma high density lipoproteins by a simple precipitation procedure.

Rapid method for the isolation of lipoproteins from human serum by precipitation with polyanions

Publisher Summary This chapter discusses lipoprotein–polyanion–metal interactions. Virtually all the plasma lipids are combined with specific proteins in the form of lipoproteins. In the presence of divalent cations, sulfated polysaccharides and sodium phosphotungstate can precipitate at neutral pH all the lipoprotein classes, namely, chylomicrons, very low-density lipoproteins (VLDL), low density lipoproteins (LDL), and high-density lipoproteins (HDL). This precipitation is dependent on the nature of the anion and cation, the concentration of reagents, and the ionic strength. The formation of an insoluble complex is more easily achieved with chylomicrons and VLDL than with LDL, and in turn more easily with LDL than with HDL. This is related to the protein:lipid ratio and not to the composition of the lipid moiety of the individual lipoproteins. Under certain conditions, the precipitation of LDL is complete and selective. By varying the ionic strength, differential precipitation of chylomicrons, VLDL, and LDL, followed by turbidimetric estimation of these lipoproteins, can be accomplished. Serum lipoproteins are also precipitated by divalent cations and polyphosphates, tetracyclines, or anionic detergents.

Lipoprotein-polyanion-metal interactions.

Precipitation of chylomicrons and very low density lipoproteins from human serum with sodium lauryl sulfate

Turbidimetric estimation of chylomicrons and very low density lipoproteins in human sera after precipitation by sodium lauryl sulfate.

[Isolation of rabbit antibodies against the proteins of human serum from the specific precipitate after adsorption of antigens by barium sulfate with acid pH. Study of the anti-beta lipoprotein antibodies].

H.R. Scholnick

Papers

Rapid method for the isolation of lipoproteins from human serum by precipitation with polyanions

Lipoprotein-polyanion-metal interactions.

Precipitation of chylomicrons and very low density lipoproteins from human serum with sodium lauryl sulfate

Turbidimetric estimation of chylomicrons and very low density lipoproteins in human sera after precipitation by sodium lauryl sulfate.

[Isolation of rabbit antibodies against the proteins of human serum from the specific precipitate after adsorption of antigens by barium sulfate with acid pH. Study of the anti-beta lipoprotein antibodies].