Biomedical subjects

V Regnault

Publications and source records attributed to V Regnault.

42 records · Page 3Linked to original sources

PubMed1988

Affinity purification of human plasma fibronectin on immobilized gelatin.

Several problems are associated with the biospecific affinity purification of plasma fibronectin on gelatin-Sepharose. Large-scale development of this purification procedure requires optimization of adsorption and elution conditions. The adsorption capacity depends on the amount of gelatin coupled to the Sepharose, the residence time, the temperature and the amount of fibronectin loaded on the adsorbent. Elution of adsorbed fibronectin with 3 M urea leads to incomplete recovery. The elution yield was found to vary with both the gelatin concentration and the amount of adsorbed fibronectin. Despite the incomplete elution, the adsorption capacity did not decrease after twelve consecutive isolation procedures. Under optimized conditions, the method described here provides a rapid, single-step and convenient way for the isolation of pure and functional fibronectin, either for analytical or large-scale preparative purposes.

Adsorption↗

PubMed1988

[Highly purified, functionally active human fibronectin preparation].

Fibronectin has been purified by gelatin-Sepharose affinity chromatography from fresh frozen human plasma. The bound fibronectin was eluted with 3 M urea. The purity of the fibronectin obtained has been checked on (immunoelectrophoresis, polyacrylamide gel electrophoresis, FPLC). Biological activity of the purified molecule has been monitored by means of three assays: quantitation of the gelatin-binding activity by ELISA, quantitation of the fibronectin-mediated attachment of fibroblasts on plastic and evaluation of the opsonic activity (uptake of gelatin latex particles by a murine macrophage line). When deep-frozen, fibronectin retains all of its properties. This highly purified and functional fibronectin fulfills the basic requirements for a standard reagent. It will allow to investigate physicochemical and functional alterations of various fibronectins.

Cell Adhesion↗

PubMed1988

[Immunosorption of apolipoproteins B. Optimization of the method in an in vitro bench test].

The aim of the present study was to determine optimum conditions for preparation and use of immunoadsorbents for removal of apolipoprotein B from plasma. An in vitro study was carried out to optimize different chromatography parameters: linear flow rate, apo B quantity loaded, gel regeneration conditions. Specificity of removal of apo B, stability of antibody covalent linkage and possible multiple use of immunoadsorbents were assessed. No significant loss of adsorption capacity was observed after sterilization and storage of immunoadsorbents.

Apolipoproteins B↗

PubMed1987

A potential new procedure for removing anti-factor VIII antibodies from hemophilic plasma.

A new approach for removing the anti-factor VIII antibodies in hemophilic patients by immunoadsorption is proposed. The method is based on the fact that the anti-factor VIII antibodies were predominantly of the IgG4 subclass; anti-human IgG4 antibodies were covalently linked to agarose and large amounts of anti-factor VIII antibodies can be eliminated. A study of 21 blood samples from hemophilic patients with anti-factor VIII antibodies allows us to confirm the large predominance of IgG4 in the anti-factor VIII population. In some samples, the presence of IgG3 related anti-VIII:C was checked by adsorption on an anti-IgG3 column. In a majority of cases, after IgG4 (or IgG4 + IgG3) immunoadsorption, the substitution therapy becomes possible or easier.

Antibody Specificity↗

PubMedDate not supplied

The calibrated automated thrombogram (CAT): a universal routine test for hyper- and hypocoagulability.

By using a "slow" fluorogenic thrombin substrate and continuous comparison to a simultaneously run calibrator, thrombin generation can be monitored automatically, on line, in clotting PPP or PRP at a throughput of up to 100 samples per hour. The resulting "Thrombogram" in PPP measures hypocoagulability (haemophilias, oral anticoagulants, heparins (-likes), direct inhibitors) and hypercoagulabilities (AT deficiency, prothrombin hyperexpression, prot. C and S deficiency, factor V Leiden, oral contraceptives). In PRP it is diminished in thrombopathies, in von Willebrand disease, by antibodies blocking GPIIb-IIIa or GPIb, or by antiplatelet drugs like aspirin and clopidogrel. Lupus anticoagulant both retards and increases thrombin generation. The thrombogram thus appears to be a broad function test of the haemostatic-thrombotic mechanism of the blood.

Blood Coagulation Disorders↗

PubMedDate not supplied

[Use of standard for quantitation of adhesion of polynuclear neutrophils by flow cytometry].

Adherence receptors are essential for heterotypic (endothelial cell, platelet) polymorphonuclear neutrophil (PMN) interaction. Determination of their expression level give information about activation state and functionality of PMN. Use of flow cytometry associated with an immunolabeling standard, represented by beads coated by a determined amount of immunoglobulins (Qifikit, Dako), allows analysis of specific antibody binding capacity and gives information about antigen density. Using this methodology, the exploration of surface adherence receptors, L-selectin (CD62L) and b2-integrins (CD11a-c/CD18) from PMN unstimulated and incubated with pro-inflammatory stimuli, formyl-methionyl-leucyl-phenylalanine (fMLP) and tumor necrosis factor a (TNFa), allows, on the one hand, the establishment of basal expression values on resting PNN and on the other hand, the study of PNN reactivity. This method of quantification can be applied to clinical studies as adherence receptor deficiency syndromes or inflammatory, infectious and vascular diseases.

Adult↗