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Biomedical subjects

P Dewailly

Publications and source records attributed to P Dewailly.

At least 19 recordsLinked to original sources
PubMed1979

Immunochemical determination of human apolipoprotein B by laser nephelometry.

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.

Apolipoproteins↗
PubMed1979

[Lipoprotein electrophoresis on acrylamide-agarose plates, with discontinuous acrylamide gradient].

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.

Electrophoresis, Agar Gel↗
PubMed1979

[Diagnosis of type III hyperlipoproteinemia: contribution of an air-driven ultracentrifuge associated with an original tube-slicer (author's transl].

Diagnosis of type III hyperlipoproteinemia requires preparative ultracentrifugation in order to measure the cholesterol/triglyceride molar ratio into isolated d less than 1.006 lipoproteins. The authors describe an ultracentrifugation micromethod which needs 600 microliter of serum and can be completed within three hours (Airfuge Beckman instruments). An original tube-slicer allows the separation of the d less than 1.006 lipoproteins located into top fractions. This simple micromethod might confirm diagnosis of type III in patients and would be useful for clinical laboratories.

Cholesterol↗
PubMed1979

Effects of unsaturated fatty acids in phospholipids on the in vitro activation of the lipoprotein lipase and the triglyceride lipase.

The effects of different types of phospholipids on the lipoprotein lipase (LPL) and on the hepatic triglyceride lipase (TGLH) were studied by comparative in vitro incubation. Substrates were prepared by homogenization in glycerol of 3H-labelled triolein plus phosphatidylcholine (either dipalmitoyl PC, or ovolecithin or highly unsaturated PC, EPL Nattermann). Enzymes were obtained from rat adipose tissue, myocardium, lungs and liver and human adipose tissue and post-heparin plasma, respectively. The enzyme activities as determined in mmol/ml medium showed differences of highly statistical significance (p less than 0.001). In any tissue investigated the enzyme activities of LPL or TGLH followed the sequence: highly unsaturated PC (EPL) greater than ovo-lecithin greater than dipalmitoyl-lecithin. This was true for the enzymes of rat and human origin as well. It was concluded that the observed LPL and TGLH activation may account for the beneficial therapeutic effects of highly unsaturated phosphatidylcholine (EPL) in human hyperglyceridemias.

Adipose Tissue↗
PubMed1979

Determination of amniotic fluid phospholipids by thin-layer chromatography, with use of a hydrogen flame ionization detector.

We describe a new specific method for measuring lecithin, sphingomyelin, and phosphatidylglycerol in amniotic fluid by thin-layer chromatography, with use of a hydrogen flame ionization detector. After extraction and acetone precipitation to isolate surface-active lecithin, the phospholipids are separated on a thin rod of refractory and chemically stable material, having an outer coating of a bonded, sintered partition medium. Two solvent systems are used to develop the chromatograms, chloroform/methanol/water to separate lecithin and sphingomyelin, tetrahydrofuran/methylal/methanol for phosphatidylglycerol. Then the rod is passed through an hydrogen flame; the resulting ions produced generate a current, which is amplified and fed to a potentiometric recorder. The height of integral curves was proportional to the area under each peak. For quantitation we used an internal standard (lysolecithin in the first system. phosphatidyldimethylethanolamine in the second). The method requires less than 5 mL of amniotic fluid; results are available within 6 h.

Amniotic Fluid↗
PubMed1978

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, linolenic 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 beta-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.

Animals↗
PubMed1978

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.

Antibodies↗
PubMed1978

Enzyme immunoassay for human apolipoprotein B, the major protein moiety in low-density- and very-low-density lipoproteins.

We used enzyme immunoassay to measure apolipoprotein B concentration in human plasma. Pure lipoprotein B was isolated from serum samples of fasting normolipidemic subjects by sequential preparative ultracentrifugation and coated to a polystyrene tube surface by adsorption. Human serum samples and rabbit antiserum to human apolipoprotein B were incubated with the solid-phase lipoprotein B. Soluble antigen competed with solid-phase antigen for binding to antibodies. After washing, peroxidase-labeled sheep antibodies against rabbit immunoglobulins were added, and after further washing the bound label was assayed. This provided a direct measurement of the soluble antigen. The best technical conditions for the assay were determined. The minimum detectable concentration was 1 microgram per assay. The enzyme immunoassay yielded values that compare favorably with those obtained by radial immunodiffusion (r = 0.84) and by rocket immunoelectrophoresis (r = 0.80). The assay offers several advantages over existing techniques: sensitivity, specificity, simplicity, ane non-use of radioisotopes.

Apolipoproteins↗
PubMed1978

[Adipocyte size in primary hypertriglyceridemia with and without obesity (author's transl)].

Adipose tissue cellularity of patients with endogenous hypertriglyceridemia whether associated with obesity or not has been studied by means of a semiautomatic method of counting and sizing osmium tetroxide fixed adipocytes. Cell population distributions were analyzed by mathematical computation. The Coulter Counter system was able to determine mean diameter (or volume) and cell size dispersion which defined adipocyte population. An overall shift of cell population size has been found to characterize adipose tissue cellularity of the different groups examined. Adipocyte population in the obese was defined by increased fat cell size with overlapping distributions between both groups of same weight. Nevertheless normolipemic obese patients were characterized by larger cell size than hypertriglyceridemic subjects matched for adiposity index. The results are discussed in relation to the removal defect found in endogenous hypertriglyceridemia.

Adipose Tissue↗
PubMed1977

[Exact determination of the lecithin/sphingomyelin ratio in amniotic fluid. Suggestion of a reference methods (author's transl)].

Pulmonary maturity of the fetus can be evaluated by the lecithin/sphingomyelin (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. less than 9%) for the measurement of Lp/S ratio and gives with accuracy the concentrations of Lp, avoiding possible errors in interpretation of Lp/S. Our results show that at 35 weeks of normal gestation, Lp/S ratio is about 2 and Lp concentration, 10 mg/1.

Amniotic Fluid↗
PubMed1977

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.

Animals↗
PubMed1977

[Perfusion of isolated rat liver. Utilization of a perfusion without heparin. Validity of the preparation].

The blood and liver giver animals are given "Tromexan" for a period of three days. The blood defibrination is finished off by shaking. The perfusion is made of defibrinated blood to which is added a compounding of mineral salts, albumin and glucose in adequate proportions. The fluid is used during 150 minutes with a biliary flow of 4 ul/minute (instead of 8 in perfusions with heparine). The validity of the preparation is tested by biliary acids, cholesterol and Brom Sulfon Phtalein biliary elimination research. This fluid can be used when heparin is avoided: for example in a case of investigation of fat emulsion scrubbing.

Animals↗