P. Dewailly

Plasma levels of VLDL- + LDL-cholesterol, HDL-cholesterol, triglycerides and apoproteins B and A-I in a healthy population Influence of Several Risk Factors

Plasma apo B and apo A-I were determined in 477 subjects (206 males and 271 females) by laser immuno-nephelometry. Measurements of VLDL- + LDL-cholesterol, HDL-cholesterol and triglycerides were done simultaneously. VLDL- + LDL-cholesterol and apo B values were similar in males and females and increased with age. HDL-cholesterol and apo A-I values were higher in females but stable with age. Different regression curves (HDL-cholesterol vs apo A-I) were obtained in males and females and a negative correlation was found between HDL-cholesterol or apo A-I and triglycerides. Increased body weight was associated with higher values of VLDL- + LDL-cholesterol, apo B and triglycerides in both sexes but lower values of HDL-cholesterol and apo A-I essentially in males. Finally, the study provides evidence of a relationship between smoking and alcohol consumption on the one hand, and HDL-cholesterol and apo A-I on the other.

Immunochemical determination of human apolipoprotein A-I by laser nephelometry

Abstract The Hyland laser nephelometer PDQ system for the assay of apolipoprotein B (apo-B) in human serum is described. Within and between-batch precision, accuracy and reliability are discussed. This instrument represents an important development in the immunochemical assay of apo-B, and the speed, precision, and convenience of the methodology make such a system attractive. Quantitation of apo-B was assessed in normal and hyperlipaemic subjects. Comparisons were made with two other specific and sensitive immunological methods for quantifying apo-B: enzymeimmunoassay (EIA) and rocket immunoelectrophoresis (RIE). Results obtained by the three methods correlated very well.

Changes in rat heart phospholipid composition after rapeseed oil feeding

The influence of long duration rapeseed oil feeding with high or low levels of erucic acid has been investigated on rat heart phospholipids. The rats treated for 20 wk with rapeseed oil containing 46.2% erucic acid showed a twofold increase in the sphingomyelin content of the heart. Treatment with primor rapeseed oil (3.7% erucic acid) for 20 wk did not modify phospholipid composition of rat heart. The fatty acid patterns of phosphatidylethanolamine and phosphatidylcholine were slightly influenced by the high erucic rapeseed oil; eicosenoic acid was incorporated preferentially into position one, but erucic acid showed a random distribution in both. After high erucic rapeseed oil feeding, 22∶1 was incorporated into cardiolipin (5.6%) and sphingomyelin (10.5%). The incorporation of 22∶1 into sphingomyelin was associated with an increase of the percentage of 24∶1 (14.6%) and a decrease of saturated long chain fatty acid (22∶0, 24∶0) percentages. Primor rapeseed oil caused a slight increase of 24∶1 and a decrease of 22∶0 and 24∶0 in rat heart sphingomyelin. As cardiolipin is localized in the inner membrane of mitochondria and sphingomyelin in plasma and microsomal membranes, the acyl-moiety alterations of both phospholipids might be correlated to the pathological lesions of rat heart after a long duration of rapeseed oil feeding.

Changes in fatty acid composition of cardiac mitochondrial phospholipids in rats fed rapeseed oil

Male Wistar rats were fed rapeseed oil containing high or low levels or erucic acid for 20 weeks, and changes in the fatty acid composition of cardiac mitochondrial phospholipids were studied. Treatment with rapeseed oil containing 46.2% erucic acid showed incorporation of 22∶1 (5.6%) into isolated cardiolipin from heart mitochondria. After high or low (3.7%) erucic rapeseed oil feeding, linoleic acid was slightly incorporated into cardiolipin. Moreover, both of these rapeseed oils induced a significant increase of linoleate-arachidonate ratio in phosphatidylethanolamine and phosphatidylcholine. This ratio was also significantly increased in fatty acids esterified to the β-position of these phospholipids. On the basis of such results, we have to consider the role of linolenic acid which is present at a high level in the different rapeseed oils used, as a possible inhibitor of heart microsomal enzymes involved in linoleate arachidonate conversion. Such alterations might account for mitochondrial fragility and myocardial lesions obtained in long term rapeseed oil feeding experiments.

Electrophorese des lipoproteines seriques sur plaque de gel d'acrylamide-agarose, en gradient discontinu d'acrylamide

Abstract We describe a modified lipoprotein electrophoresis on acrylamide gel. The lipoproteins, prestained with Sudan Black, are separated by running on acrylamide-agarose gels, with two different concentrations of acrylamide and a constant concentration of agarose. The sera are deposited in the first gel (2% acrylamide). Chylomicrons remain at origin and other lipoproteins run through the first gel to the second one (3% acrylamide gel). VLDL stays at the junction of both gels, LDL and HDL are separated in the 3% acrylamide gel. By this technique, we were able to detect an increase of Lp(a) and to identify the different types of hyperlipoproteinemia. After running, the plates can be treated for storage.

Experimental studies on the regulation of myocardial and adipose tissue lipoprotein lipase activities in rat

Summary Lipoprotein lipase (LPL) activity was studied in rat epididymal fat and heart. In adipose tissue, diet LPL induction lowered with age and was inhibited during cold exposure. Nicotinic acid, glucagon and norethindrolone propionate enhanced LPL activity and estrogens showed an opposite effect. In heart, starvation and cold exposure induced LPL activation; glucose and nicotinic acid decreased LPL activity, but hormones had no significant effect. To some extent, AMP c seems to be a mediator regulating LPL activity in adipose tissue. In heart the regulation mechanisms are still controversial.

Plasma Removal of Intravenous Essential Phospholipids in Man

Essential phospholipids intravenously injected in man (n = 20) caused a rapid increase of the plasma lipid phosphorus to 108% (p < 0,001) within the first 2 minutes, followed by a decrease to the control level within the subsequent 10 minutes. Simultaneously, the percentage of linoleic acid in plasma lecithins was enlarged during the first two minutes, but remained increased (p < 0.05) for at least 40 minutes. The increase of linoleic acid was similar in the lecithins of different plasma lipoproteins, but did not occur in plasma phosphatidyl-ethanolamines. Obviously, the excess of phospholipids was quickly removed from the plasma, but either part of the plasma lecithins as a whole or their fatty acids were exchanged for the injected moieties.

Inhibition enzyme immunoassay. Application to human apolipoprotein B

Inhibition enzyme immunoassay was applied to human apolipoprotein B (apo-B) from plasma. The technical conditions of the assay were determined. The detection limits of the assay were 200 ng to 10 microgram/ml. Correlation coefficients obtained between enzymoassay and rocket immunoelectrophoresis on one hand and radial immunodiffusion on the other were respectively 0.84 and 0.80. The inhibition enzymoassay provides a specific and highly sensitive method for the quantitation of apo-B.

Determination precise du rapport lecithine/ sphingomyeline dans le liquide amniotique: Proposition d'une methode de reference

Abstract Pulmonary maturity of the fetus can be evaluated by the lecithin/sphingo-myelin (L/S) ratio in amniotic fluid. To existing methods of lipid extraction, precipitation with acetone and chromatography, we add a simple and accurate estimation of sphingomyelins (S) and precipitated lecithins (Lp) without acid digestion. The method is reproducible (C.V.

Intérêt et signification du test d'hyperlipémie par voie veineuse dans l'exploration des hyperlipémies étude de ses variations sous l'effet de l'alcool

Summary The fractional removal rate of fat emulsion injected intravenously has been measured in several groups of subjects: controls, patients with hypercholesterolaemia or hypertriglyceridaemia. The intravenous fat tolerance test was also estimated in controls before and after a short ethanol perfusion. The fractional removal rate (K 2 ) is low in patients with hypertriglyceridaemia and the results obtained suggest that the intravenous fat tolerance test provides a simple mean for an estimation of the removal of triglycerides from the blood. After a constant infusion of alcohol in healthy subjects a significant reduction of K 2 is found.