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La conjonction des evenements conduisant a la plaque d'atherome est complexe; cette complexite est majoree chez le malade diabetique chez qui les troubles du metabolisme des lipides sont aggraves par cet etat morbide. Dans ces conditions; l'etude du risque atherogene lie au cholesterol (RAC) est utile pour apprecier l'importance du risque cardio-vasculaire encouru par le malade et servir aussi comme un indice de la normalisation metabolique du diabete

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Sur une population rigoureusement selectionnee; indemne de tout facteur de risque en rapport avec les parametres du bilan lipidique de routine pratique a Cotonou; les auteurs ont determine la prevalence des dysfonctionnements du metabolisme des lipides. Il est important de parfaire ce travail par le dosage; aujourd'hui possible localement; des apolipoproteines et des lipoparticules qui sont des marqueurs plus sensibles et plus fiables de l'atherosclerose (7; 10; 13). Seule une etude multicentrique; bien conduite; peut permettre de faire le point de la question en Afrique afin de determiner le risque encouru par les populations et de moduler la conduite a tenir devant les depassements anormaux des lipides a potentialite atherogene chez l'Africain

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We developed a sandwich-type enzyme immunoassay to measure cholesteryl ester transfer protein (CETP) mass in human plasma. A specific monoclonal antibody (TP-4) that recognizes an epitope located in the C-terminal domain was used for antigen capture and an anti-CETP peptide antibody directed against the 290-306 residue was used for detection. Bound antibodies were revealed with an antibody-peroxidase conjugate specific for rabbit IgG. The presence of 10 mL/L Triton X-100 in the incubation buffer increased antigen exposure of CETP in plasma. The curves for CETP in standard plasma and partially purified CETP were parallel. This technique is rapid (results within 6 h), accurate, precise (mean intra- and interassay CVs 3.6% and 8.4%, respectively), and simple to perform. Assay sensitivity is at microgram concentrations, with a working range of 20-200 micrograms/L. In 40 normolipidemic healthy subjects, the mean CETP concentration in plasma was 1.1 +/- 0.4 mg/L. A strong correlation between CETP concentration and CETP activity (r = 0.91, n = 42) was observed. In plasma, the bulk of CETP was found in high-density lipoprotein fractions. Therefore, this assay may be a useful tool for investigations of CETP and its significance in relevant diseases.

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Les auteurs indiquent dans ce travail les methodes de dosage et le role possible des differentes fractions des HDL du serum sanguin

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A non-competitive enzyme linked immunosorbent assay (ELISA) has been developed to quantitate apolipoprotein E (Apo E) concentrations in serum and in isolated lipoproteins. Microtiter plates coated with affinity-purified antibodies to Apo E were used and the Apo E bound to the plates was estimated with peroxidase-labelled antibodies to Apo E. The average concentration of Apo E in the serum from normolipidemic subjects (n = 132) was 54 +/- 19 mg/l. The within and between assay coefficients of variation were 4.65 and 7.08%, respectively. The standard curves for Apo E in serum, in VLDL and in HDL were parallel. There was a good correlation (r = 0.81) between estimation of Apo E by our assay and that by electroimmunoassay. Assay sensitivity (1 ng of Apo E) was sufficient to enable a study of the distribution of Apo E in plasma lipoproteins separated by density gradient ultracentrifugal fractionation.

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This paper describes a procedure for the rapid isolation of urea-soluble apolipoproteins (apo) from delipidated human very-low- and high-density lipoproteins using anion-exchange fast protein liquid chromatography. The separation was complete within 30 min and peaks corresponding to apolipoproteins A-I, A-II, C-I, C-II, C-III0, C-III1, C-III2 and E were identified by comparing their chromatographic, electrophoretic and immunological behaviour with that of purified standards of each protein. A second purification step is necessary to obtain pure apolipoproteins. Apo E, which is difficult to purify by conventional chromatography, has been obtained in a good yield. The apo C-II that was obtained produced a symmetrical peak on chromatography but three bands in isoelectric focusing. The method can be upgraded to a preparative scale and offers the possibility of direct purification of apolipoproteins both from high-density lipoproteins and (following preliminary gel chromatography) from very-low-density lipoproteins.

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We used a noncompetitive immunoenzymometric assay to measure the concentration of total apolipoprotein C-III in human sera. Affinity-purified antibodies to apolipoprotein C-III were adsorbed to the surface of microtiter plates. After washing, this solid-phase antibody was incubated with antigen (serum from fasting subjects), washed, and then incubated with peroxidase-labeled purified antibodies to apolipoprotein C-III. After a last washing, the bound label was assayed, providing a direct measurement of the antigen. Optimized technical conditions for the assay yielded assay CVs of 3.5 and 5.6% for within- and between-run precision, respectively. Analytical recovery of apolipoprotein C-III added to a serum was quantitative (97%). This noncompetitive assay can be used to measure apolipoprotein C-III in different lipoprotein fractions (very-low or high-density fractions) and yields values that compare favorably with those obtained by electroimmunoassay (r = 0.94). The assay offers several advantages over existing techniques--sensitivity, specificity, simplicity, and no use of radioisotopes--and hyperlipemic samples can be used.

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We describe an isoelectric-focusing method for rapidly separating and quantifying apolipoprotein (apo) C-II and C-III subspecies of triglyceride-rich lipoproteins. Concentrated very-low-density lipoproteins (VLDL) or delipidated apo VLDL are focused on dry acrylamide plates, after their rehydration with ampholytes and urea. Apo C-II and apo C-III in VLDL are resolved into four major bands--C-II (pI 5.01), C-III0 (pI 5.10), C-III1 (pl 4.92), and C-III2 (pI 4.84)--at the same pI values as for purified apo C. This precise technique can be used without delipidating VLDL. The relative percentage of C apoproteins found in VLDL from plasma of normal subjects agreed with previously published data. The ratio of apo C-II to apo C-III decreased in patients with chronic renal failure or with coronary artery disease.

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Few papers have been devoted to the study of apolipoprotein A-II (apo A-II), one of the major peptides contained in HDL, probably because of the methodological difficulties associated with its assay. The aim of this study is to provide the clinical biochemist with a simply easy to use assay technique. We have been able to demonstrate the practical value of apo A-II assay in hepatology and in the detection of excessive drinkers. On the other hand, our results indicate that apo A-II is not a parameter of choice for the detection of coronary atherosclerosis.

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We describe a simplified electroimmunoassay for quantification of human apolipoproteins A-I and B on prepared plates. A solution of agarose at 55 degrees C, containing hydroxyethylcellulose and antibodies, is poured onto a plastic film and allowed to gel. Wells are punched in the gels and the plates are dried for storage. Before use, they are rehydrated and buffered. We use succinylated Sudan Black to prestain lipoprotein fractions of plasma. After electrophoresing samples of plasma or standards for 3 h at 4 degrees C at 12.5 V/cm, we measure the peak heights and read the results from a standard curve prepared by using calibrated sera of known apolipoprotein B and A-I content as secondary standard. The within- and between-assay coefficients of variation were less than 4% in all cases. Results correlated well with those obtained by classic electroimmunodiffusion. Subjects with confirmed atherosclerotic lesions had significantly (p less than 10(-9)) lower ratios of apolipoprotein A-I to apolipoprotein B, compared with ratios in controls.

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