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Biomedical subjects

M Chassaigne

Publications and source records attributed to M Chassaigne.

At least 37 records · Page 2Linked to original sources
PubMed1989

Modification of partial pressure of oxygen (P50) in mammalian red blood cells by incorporation of an allosteric effector of hemoglobin.

Internalization of inositol hexaphosphate (IHP) in mammalian red blood cells (RBC) produces a modification of the hemoglobin-oxygen affinity, leading to a rightward shift of the dissociation curve. The process of incorporation, based on an osmotic shock, has been tested on RBC of different species. Two dialysis protocols have been defined to transform RBC, the first one for small volumes in a cellulose bag and the other for larger volumes using a commercially available dialysis device. Different optimal conditions must be used for each species. Most of the cellular characteristics of the transformed RBC having encapsulated IHP are similar to those of native cells. For several species, such modified RBC could be reinfused and used for physiological studies.

Allosteric Regulation↗
PubMed1987

Oxygen transport to tissue modified by entrapment of an allosteric effector of haemoglobin in erythrocytes.

Oxygen affinity of haemoglobin is modulated by several parameters such as the allosteric effector 2-3 DPG for most mammalians. Inositol hexaphosphate (I.H.P.) exerts the same effect on haemoglobin. A previously developed new methodology for the entrapment of drugs into erythrocytes has been adapted to I.H.P.; it is based on a reversible osmotic shock. I.H.P. loaded red blood cells have characteristics very similar to those of native cells. The decrease in oxygen affinity is related to the dose of encapsulated I.H.P. In piglets, transfusion of such cells has led to an increase of oxygen extraction from haemoglobin. Normal anesthetized animals regulate their oxygen consumption by reduction of cardiac output.

2,3-Diphosphoglycerate↗
PubMed1977

[Quantitative and thermodynamic study of B antigen in a family including individuals with phenotypes B 3 and AB 3].

Four B3 and one A1B3 erythrocyte samples belonging to the same family were studied using several series of quantitative measurements: percentage of agglutination, agglutination kinetics and thermodynamic methods. For this last assay the erythrocytes were used fresh and after treatment by formalin. From the obtained results evidence was given that while B antigen density was lower in A1B3 than in B3O cells, the reactive structure is qualitatively the same in these two kinds of cells. The enthalpy change of the reaction of this B3 antigen with a non stimulated anti-B from A1O individual was -- 5,000 cal/mole, i.e. weaker than when normal B cells were concerned (-- 16,000 cal/mole).

ABO Blood-Group System↗
PubMed1976

[Radioimmunoassay of antihemophilic factor A].

A radioimmunological method for the estimation of anti-haemophilic factor A was perfected and studied, making it possible to measure factor VII antigen as distinct from procoagulant factor VIII activity. The method uses a rabbit anti-factor VIII antibody, purified and labelled with I125. The technique of estimation is based upon the differential precipitability of specific factor VIII antigen-antibody complexes, which precipitate with 25 per cent saturated ammonium sulphate and of free antibody which does not precipitate under these conditions. The method is reproducible and sensitive, with the possibility of measuring 0.3 per cent of factor VIII antigen, i.e. 0.003 units/ml. Its specificity is confirmed by the absence of factor VIII antigen in a patient suffering from a severe form of von Willebrand's disease. Using this technique, normal subjects were found to have 96 +/- 31 per cent of factor VIII antigen in comparison with a pool of 25 normal plasmas. Haemophiliacs tested had, as would have been expected, antigen levels close to normal.

Antibodies, Anti-Idiotypic↗
PubMed1976

[Cad antigen in the French population].

An investigation of Cad phenotypes in the French population had been carried out in 1973, in four Blood Transfusion Centers (Mulhouse, Nancy, Paris, Versailles), B and O red cells were tested with the Dolichos Biflorus lectin. Out of 78.528 donors, 56 were found to have the Cad antigen on their red cells. The mean frequency was 0,07%. Nevertheless, this frequency varied among the four above mentioned Blood Transfusion Centers: the observed differences were probably due to the preparation procedure of the Dolichos biflorus extract. The family investigation permitted the analysis of four families with at least three Cad individuals. The independence of the Cad system and of Auberger, Gc, Hp, C'3, PGM, Pac and ADA was demonstrated. A quantitative agglutination study on these Cad samples using the Dolichos biflorus lectin,and a selected AB serum showed a high variability of the erythrocyte Cad Strength, even within one family. Most Cad samples were found polyagglutinable when a sensitive technique and selected AB sera were used. All adult sera contained an anti-Cad1 antibody, except Cad1 individuals. Although strong Sda reactivity was always found in Cad red cells, the anti-Cad and anti Sda specificities were not identical: this was demonstrated by the absorption and inhibition tests of anti-Cad and anti-Sda reagents absorption and inhibition tests of anti-Cad and anti-Sda reagents with Sda material. From thf Cad red cells, there was no evidence of the existence of separable anti-A1 and anti-Cad agglutinins in the Dolichos biflorus lectin.

Blood Group Antigens↗
PubMed1976

[Partial trisomy 21 (21q21 - 21q22.2)].

An abnormal chromosome 21 is reported in a child with a phenotype strongly reminiscent of trisomy 21 syndrome. It is shown to result from duplication of the segment 21q21 leads to 21q22.2. Comparison of the phenotype with that of other partial and total trisomics shows that the characteristic features of the trisomy 21 syndrome (mongolism), the mental retardation in particular - is due to trisomy 21q22.2 and perhaps 21q22.2.

Alkaline Phosphatase↗