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Biomedical subjects

J C Fruchart

Publications and source records attributed to J C Fruchart.

At least 433 records · Page 24Linked to original sources
PubMed1986

Quantitative determination of human plasma apolipoprotein A-II by a non competitive enzyme-linked immunosorbent assay.

A noncompetitive enzyme-linked immunosorbent assay (ELISA) for apolipoprotein A-II (ApoA-II) was developed. Microtiter plates were coated with affinity purified antibodies to ApoA-II. After incubation with human plasma, the amount of ApoA-II bound to the coated plate was determined with peroxidase-labeled antibodies to ApoA-II. When pure ApoA-II or delipidated reference plasma was used as standard, a single step delipidation was required in order to unmask some antigenic sites of ApoA-II. However, the underestimated ApoA-II values in untreated samples were shown to be corrected by using intact reference plasma as secondary standard. The average concentration of ApoA-II in normolipidemic plasma was 0.376 g/l.

Antibodies↗
PubMed1986

[Methods for analyzing lipoproteins].

In recent years there have been considerable advances and changes in the investigations available to study lipoprotein metabolic disorders. The methods used up to now were based on physicochemical criteria (electrophoresis, ultracentrifugation, polyanionic precipitation). But the recent demonstration of the preponderant role of apoproteins in lipoprotein metabolism makes it essential to develop a method of analysis lipoproteins at the molecular level. Immunological methods seem to be the most appropriate and should allow us to study lipoprotein metabolism more closely.

Chemical Precipitation↗
PubMed1985

Development of a radial immunodiffusion technique employing monoclonal antibodies for apolipoprotein B determination in human plasma.

Twenty monoclonal antibodies obtained from two different fusions of SP2/0-Ag 14 cell line (non-secretor hybridoma) with human plasma low density lipoproteins have been selected. We found that a mixture formed by the 20 monoclonal antibodies was able to form a single precipitin line with human plasma low density lipoproteins by a double gel diffusion technique. Further studies revealed that only two monoclonal antibodies were needed to precipitate low density lipoproteins in gel. However, a minimum of four particular monoclonal antibodies was required to obtain an optimal precipitin ring and a linear standard curve within 24 h using a radial immunodiffusion technique. We have then compared the radial immunodiffusion performed with a monoclonal antibody mixture to those employing conventional goat and rabbit antibodies in terms of plasma apolipoprotein B determinations. The apolipoprotein B values determined by monoclonal antibodies significantly correlate with the values obtained by the technique using goat (r = 0.95; p less than 0.001) and rabbit (r = 0.95; p less than 0.001) antibodies. Our data indicate that a mixture of monoclonal antibodies can mimic conventional antibodies in terms of immunoprecipitation and apolipoprotein B determination.

Animals↗
PubMed1985

Latex immunoassay of human serum Lp(a+) lipoprotein.

A sensitive latex immunoassay for human serum lipoprotein Lp(a+) is based on direct agglutination by Lp(a+) of latex particles coated with specific antibody. The agglutination is quantified by turbidimetry using a photometer at 360 nm. The stabilization of antibody-coated latex particles by bovine serum albumin occurs under well-defined conditions (pH, concentration of bovine serum albumin, and antibody loading of latex particles). The standard curve of serum lipoprotein Lp(a+) ranges from 0.05 to 1.15 mg/l. Inter- and intra-assay coefficients of variation were less than 8% and 3%, respectively. Results were well correlated with those obtained by electroimmunodiffusion (r = 0.98, n = 108).

Humans↗
PubMed1985

Quantification of apolipoprotein C-III in serum by a noncompetitive immunoenzymometric assay.

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.

Apolipoprotein C-III↗
PubMed1984

Serum apolipoprotein A-II, a biochemical indicator of alcohol abuse.

The possible use of high density lipoprotein (HDL) cholesterol, HDL phospholipids, apolipoproteins (APO) A-I and A-II as markers of alcohol abuse was studied in 78 intemperate drinkers. The mean value for each of these parameters was higher in drinkers than in control subjects. The most significant increase was observed in the plasma apo A-II levels (+45%). A composite index of gammaglutamyltranspeptidase (GGTP) and apo A-II was superior to GGTP alone in discriminating drinkers (+14%). Moreover, apo A-II assay is simple to perform.

Adult↗
PubMed1984

Noncompetitive enzyme-linked immunoassay for apolipoprotein B in serum.

We used a noncompetitive enzyme-linked immunoassay to measure apolipoprotein B (apo-B) concentration in human plasma. Goat anti-lipoprotein B immunoglobulins were adsorbed to the surface of polystyrene balls. After washing, this solid-phase antibody was incubated with antigen (plasma from normal or hyperlipoproteinemic fasting subjects), washed, and then incubated with peroxidase-labeled goat anti-lipoprotein B IgG. After a last washing, we measured the bound label, which provided a direct measurement of the antigen. Under optimized assay conditions, the minimum detectable concentration was 50 ng per assay. The assay may be used to measure apo-B in different lipoprotein fractions (low- or very-low-density) and yields values that compared favorably with those obtained by electroimmunoassay (r = 0.86). The assay offers several advantages over existing techniques: sensitivity, specificity, simplicity, avoidance of radioisotopes, and potential for use with monoclonal antibodies.

Apolipoproteins↗
PubMed1984

[Assay of serum apolipoprotein A-II by electro-immunodiffusion on ready-for-use plates. Clinical applications].

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.

Adult↗
PubMed1984

Rapid assessment of the distribution of apolipoproteins C-II and C-III subspecies in triglyceride-rich lipoproteins by isoelectric focusing.

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.

Apolipoprotein C-II↗
PubMed1983

[Methods of biochemical analysis in hyperliproproteinemias].

In the past years, the structure and function of the plasma lipoproteins and apolipoproteins have been elucidated. The biochemical defect of several genetic lipoprotein disorders and their role in the development of atherosclerosis are now well understood. Electrophoretic separation of lipoproteins in polyacrylamide gradient gel gives an acurate characterization of the different lipoproteins and allows the phenotyping of hyperlipoproteinemia. Abnormal concentrations of plasma lipoproteins have been known for many years to be a major risk factor in the development of premature ischemic heart disease. Although large-scale epidemiological studies have focused attention on the association between above-normal concentrations of plasma lipids and coronary atherosclerosis, recent findings have shown that quantitative lipoprotein and apoprotein determination may be a more nearly accurate predictor in the recognition of atherosclerosis. The risk for vascular disease seems to be particularly associated with an increase in the concentrations of apolipoprotein B (apo B), the major protein moiety of low density lipoproteins and a decrease in apolipoprotein Al, the major polypeptide of high-density lipoproteins.

Apolipoproteins↗