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Biomedical subjects

P M Steiner

Publications and source records attributed to P M Steiner.

At least 19 recordsLinked to original sources
PubMed1978

Effects of chlorinated hydrocarbon on plasma alpha-lipoprotein cholesterol in rats.

Ten chlorinated hydrocarbons (tetradifon, Chlorobenzilate, Kepone, lindane, Kelthane, toxaphene, dieldrin, hexachlorobenzene, dienochlor, and Aroclor 1254; see below) were evaluated in rats to assess agents which might selectively elevate high-density lipoprotein cholesterol (C-HDL). Single, nontoxic doses of Aroclor, dieldrin, and Kepone elevated C-HDL at day 7 (31%, 26%, and 24%, respectively, p less than 0.05). The C-HDL elevations were maintained at days 21 and 60 (28% and 31%, p less than 0.01) in the Aroclor group, while C-HDL returned to baseline in the dieldrin and Kepone groups. Liver function tests were unchanged from control, suggesting that the changes in C-HDL were not the consequence of hepatotoxicity. The hepatic microsomal cytochrome P-450 content of animals receiving Aroclor, dieldrin, and Kepone was 67%, 56%, and 44% higher than control values (p less than 0.02), indicating probable hepatic enzyme induction. If HDL (an antiatherogenic lipoprotein) is also selectively elevated by chlorinated hydrocarbons in man, then analogues might potentially be developed as antiatherogenic pharmacologic agents. Alternatively, the implications of man's exposure to halogenated hydrocarbons may be better understood.

Cholesterol↗
PubMed1978

Hypercholesterolemia and hyper-alpha-lipoproteinemia in schoolchildren.

Elevated levels of high-density lipoprotein cholesterol (C-HDL) can explain apparent hypercholesterolemia in some children, and high C-HDL levels may aggregate in families. In this study, 17 kindreds were identified by virture of hypercholesterolemic proband children whose hypercholesterolemia was accounted for the elevated C-HDL levels Family lipod and lipoprotein sampling revealed three-generation vertical appearance of elevated C-HDL level in two kindreds, and two-generation vertical appearance in eight additional kindreds. Since CHDL level is inversely associated with coronary heart disease in adults, it is important to quantitate C-HDL and low-density lipoprotein cholesterol (C-LDL) in hypercholesterolemic children and to identify those with putatively reduced risk (elevated C-HDL level) or increased risk (elevated C-LDL level).

Adolescent↗
PubMed1977

Neonatal familial hyperalphalipoproteinemia.

A kindred with four-generation vertical transmission of familial hyperalphalipoproteinemia was ascertained by measurement of elevated levels of cord blood high-density lipoprotein cholesterol (C-HDL) in a neonatal propositus. Quantitation of cord blood C-HDL coupled with family studies and longitudinal follow-up allows the diagnosis of familial hyperalphalipoproteinemia in infancy.

Blood Protein Disorders↗
PubMed1977

Black-white similarities in cord blood lipids and lipoproteins.

Cord blood lipoproteins were quantitated in 117 neonates (58 white, 50 black) to assess for potential early expression of racial lipid distinctions. In comparison of black and white neonates there were no differences in total cholesterol (TC), high-density lipoprotein cholesterol (C-HDL), low-density lipoprotein cholesterol (C-LDL), C-HDL/C-LDL, or C-HDL/TC. Cord blood triglycerides were slightly higher in black neonates (p = 0.02). Unlike certain adult black-white comparisons and within the limits of "genicity" as expressed by cord blood lipoproteins, there were no racial differences in C-HDL, C-LDL, and total cholesterol.

Black People↗
PubMed1976

High-field 13C NMR Studies of certain normal and abnormal human plasma lipoproteins.

High-field (63.4 kilogauss) Fourier transform nuclear magnetic resonance spectroscopy 13C in natural abundance has been used to study the structural organization and molecular dynamics of constituent lipids of normal human very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL). The same method was used to study the abnormal beta-VLDL of two type III hyperlipoproteinemia patients having markedly differing ratios of VLDL cholesterol to triglyceride (0.3 and 0.6, respectively). Resolution obtained at 63.4 kilogauss has made possible the assignment of several additional resonances of cholesterol ring carbon atoms, not resolved in earlier studies at lower fields, in the VLDL spectra. The rotational reorientation of the ring portion of cholesteryl esters in VLDL (normal) and beta-VLDL (abnormal) is not highly anisotropic and is similar to that for cholesteryl esters disolved in excess triolein. The rotations of cholesteryl esters in LDL are more highly anisotropic and significantly more restricted. The results suggest that the structural organization of the lipid components in beta-VLDL resembles that found in normal VLDL but differs significantly from that for normal LDL.

Cholesterol↗
PubMed1976

A study of the heparin-manganese chloride method for determination of plasma alpha-lipoprotein cholesterol concentration.

To assess the limits of the heparin MnCl2 precipitation method for quantitation of alpha-lipoprotein cholesterol (C-HDL), effects of varying final McCl2 and heparin concentrations were studied, and the precipitation method was compared to preparative ultracentrifugation. In 65 parallel plasma aliquots, C-HDL (X+/-SE) determined by ultracentrifugation (54.3+/-1.8 mg/dl) correlated significantly (r=0.98, P less than 0.001) with the precipitation method (56.0+/-1.9 mg/dl). C-HDL by ultracentrifugal and precipitation methods were also similar in 16 subjects with triglycerides ranging from 150 to 312 mg/dl (41.4+/-2.6, 43.4+/-2.8, r=0.97, P less than .001). A constant amount of cholesterol in the supernatant was measured over a final McCl2 range of 0.046-0.23 M, and cholesterol values in the supernatant at final McCl2 concentrations of 0.046, 0.05, and 0.055 M did not differ from each other, P greater than 0.1. However, cholesterol levels in the supernatant at final MnCl2 concentration of 0.042 M differed from those at concentrations of 0.046, 0.05, and 0.055 M, P less than 0.05 and the amount of supernatant cholesterol increased as the final McCl2 concentration was reduced from 0.042 to 0.02 M. A constant amount of cholesterol in the supernatant was measured over a heparin concentration range of 92-734 USP units/ml. The final MnCl2 and heparin concentrations of 0.046 M and 184 USP units/ml, which are incorporated in widely used procedures, gave C-HDL values for the precipitation method which were in close agreement with the ultracentrifugal method. There is no evidence for a heparin-Mn++ precipitation of HDL and systematic underestimation of HDL by the precipitation method. However, the final MnCl2 concentration is very near the minimum required for accurate measurement of C-HDL. To preclude incomplete precipitation of low and very low density lipoproteins by insufficient manganese concentration, an increase of the manganese concentration should be considered.

Chemical Precipitation↗