[Serum determination of IgG, IgA, IgM, transferrin and haptoglobin. I. Attempt at normalization of results]. / Dosages sériques d'IgG, IgA, IgM, transferrine et haptoglobine. I. Essai d'harmonisation des résultats.

This study demonstrates the advantages and limitations of normalizing results for five serum proteins (IgG, IgA, IgM, transferrin and haptoglobin), analysed in liquid phase on ten different systems (open clinical chemistry and dedicated protein analysers). Seven sets of results from normal and pathological sera (without monoclonal proteins) were compared using: - calibrators supplied by each manufacturer; - - serial dilutions of a single stabilized pool of liquid serum. In addition to validating the quality of the stabilised serum, we have been able to identify: - significant variations in results using different analytical systems for the same sample; - a major reduction in these variations, often greater than 50%, through normalization using a common serum pool. In some two thirds of the cases, this reduction brought the degree of variation into an acceptable range.

Properties of partially purified bovine brain dopamine beta-hydroxylase.

Dopamine beta-hydroxylase has been partially purified from bovine brain. A 140-fold purification factor was achieved using solubilization with Triton X-100, ammonium sulphate fractionation between 20-50 per cent saturation, affinity chromatography on concanavalin A-Sepharose 4 B and then filtration through Sephadex G200. The specific activity at the end was 51 nmoles/h/mg protein. The majority of endogenous inhibitors were lost. Immunological studies, kinetic studies, studies on the interaction with lectins and the effect of carboxylic acids on enzyme activity were carried out. Our data are in favour of the close similarity between the bovine brain and adrenal enzymes. No major differences could be found, at least with the characterization experiments using in the present study.