Search PubMed⌕ Search

Biomedical subjects

J Rousseaux

Publications and source records attributed to J Rousseaux.

At least 55 records · Page 3Linked to original sources
PubMed1981

A redox function for the Calpha2 domain of IgA immunoglobulin.

IgA1 populations were reduced over a range of dithiothreitol concentrations and the products were examined by sodium dodecyl sulfate polyacrylamide gel electrophoresis and peptide mapping. The study showed that IgA was more resistant to reduction than other immunoglobulin classes (IgG, IgM). SDS-polyacrylamide gel electrophoresis showed that intersubunit bond and H-L bond were the most labile disulfide in polymeric and monomeric IgA, respectively. Peptide mapping revealed that the itrachain disulfide of the C alpha 2 domain was more or equally sensitive to the reduction than H-L and intersubunit bonds. Electrochemical experiments demonstrated that this bond had redox properties and the possibility involving disulfide exchange is discussed.

Chemical Phenomena↗
PubMed1981

Tryptic cleavage of rat IgG: a comparative study between subclasses.

Monoclonal rat IgG belonging to the 4 rat IgG subclasses, and some IgG subclasses isolated from normal rat serum were subjected to enzymatic degradation with trypsin. Differences in the products of tryptic digestion were observed according to the IgG subclass. IgG2b and IgG2c were degraded mainly into Fab and Fc fragments. IgG1 and IgG2a appeared resistant to such cleavage. However, tryptic digestion of the latter two produced two fragments separated only in dissociating media. Results of the studies suggest that one of the fragments (mol. wt. 13,000) probably consists of most of the variable domain of the gamma heavy chain, while the second (mol. wt. 120,000) consists of the IgG deleted of the VH regions.

Animals↗
PubMed1981

[The level of glycohaemoglobin (Hb A1c) in connection with diabetes and pregnancy (author's transl)].

The authors worked out a normal curve using 379 levels obtained over 9 months in 180 normal pregnancies. 6% (with a confidence level between 4.4% and 7.6%) was usual for haemoglobin A1c. Then they compared 42 levels of glycohaemoglobin obtained from 14 pregnant diabetic patients where the mean value was 8.34%. Glycohaemoglobin A1c therefore is a good indicator or the level of stabilisation in diabetic pregnancies in the two months before the estimation is taken. It is therefore possible to think that it does indicate chronic hyperglycaemia and does seem to have a future in screening diabetic pregnancies. On the other hand it does not seem to be of any supplementary value in monitoring the fetus of the diabetic mother in the third trimester of pregnancy because of the small variations in the levels that are obtained as compared with the suddenness of fetal complications.

Birth Weight↗
PubMed1980

Studies on the incidence of rat ileocecal malignant immunocytoma: vertical transmission of the high tumour incidence.

Monoclonal immunoglobulin-secreting tumours (immunocytomas, myelomas or plasmocytomas) appear with a high or low incidence in 2 sublines, LOU/C and LOU/M respectively, of the same inbred strain of rats. Studies of the reciprocal hybrids of the first generation between both substrains have shown that the transmission of the high tumour incidence from parents to offsprings is determined by the male as well as by the female. Absence of C-type viral particles in LOU/C rats and immunocytomas derived from them suggests that this vertical transmission might be genetically mediated.

Animals↗
PubMed1979

Rat immunoglobulins.

Five immunoglobulin isotypes (or classes) have been identified in the human as well as in the rat species. The homologies between the human and the rat immunoglobulin classes have been well defined with the help of the monoclonal immunoglobulins produced by the LOU immunocytomas (plasmocytomas,myeloma tumours). The LOU rat immunocytomas model, the physicochemical and the biological properties of the rat immunoglobulins are described in this review.

Animals↗
PubMed1978

Rat mast cell-eosinophil interaction in antibody-dependent eosinophil cytotoxicity to Schistosoma mansoni schistosomula.

The involvement of IgG2a antibodies and mast cells in antibody-dependent eosinophil cytotoxicity suggested a possible interaction between mast cells and eosinophils for in vitro killing of Schistosoma mansoni schistosomula. Cell purification procedures showed that a minimum ratio of mast cells was required to obtain eosinophil cytotoxicity. The incubation of mast cells with heat-aggregated IgG2a immunoglobulins before addition to a mast cell-depleted eosinophil population induced a significant degree of inhibition of cytotoxicity, Similarly, the heat-aggregated IgG2a Fc fragment had a strong inhibitory effect whereas incubation of mast cells with Fab fragment failed to inhibit the cytotoxic effect. The Fc portion of IgG2a immunoglobulins therefore seemed to be involved in binding to the mast cell surface. Furthermore, it was demonstrated that soluble mediators released after mast cell activation either by compound 48/80, or by IgE, or IgG2a-dependent reaction had the same effect as intact mast cells. These observations suggest that the eosinophil-dependent cytotoxicity mechanism requires a signal provided by soluble mast cell mediators in addition to antibody.

Animals↗
PubMed1976

[Bisalbuminaemia in pancreatitis: structural modifications of human serum albumin by proteolytic enzymes of the pancreas (author's transl)].

Bisalbuminaemia in pancreatitis is a transient abnormality related to the presence, on electrophoresis of the serum, of a fast-moving albumin; this abnormal form is also found, in large amounts, in the ascitic or pleural effusions of the patients. Experiments reported here indicate clearly that the fast albumin can be produced by a degradation of normal serum albumin by the proteolytic enzymes of the pancreas (chymotrypsin or elastase in association with carboxypeptidases A and B). Stuctural analysis of the isolated fast albumin of the patients shows that the C-terminal end of the molecule is different from normal serum albumin, which can be understood by a limited enzymatic degradation by chymotrypsin or elastase followed by the action of carboxypeptidases. The discovery of bisalbuminaemia in a patient affected by pancreatitis is suspicious of the presence of an ascitic or pleural effusion and of a pancreatic pseudo-cyst with a fistula emerging in the effusion.

Carboxypeptidases↗
PubMed1976

Localization of J-chain and interchain disulfide bonds in a human F(c)5mu-like fragment.

The inter H-H cysteinyl peptides and the localization of the J-chain were studied in a human F(c)5mu-like fragment. The latter was found to be built up by non-covalent association of molecular forms of 140 000, 95 000 and 70 000 dalton subunits. The trimeric, dimeric and monomeric forms were obtained from gradual reduction by dithiothreitol of the major component of 140 000 daltons, thus confirming the tetrameric nature of this subunit. The latter was found to result from the association of both components of the 70 000 dalton subunit, with the participation of the inter H-H subunit bridge. Structural analysis of the labelled peptides obtained by partial reduction and alkylation showed the presence of the intersubunit disulfide bridge and of the inter heavy-heavy chain bridge of the C-terminal region, and the absence of the heavy-heavy chain bridge of the hinge region. The sequence of these peptides is identical to the sequences of the corresponding peptides of normal mmu-chains. The J-chain, which was covalently linked to this F(c)5mu-like fragment, was found to be predominantly associated within the 95 000 dalton subunit. The results showed that the J-chain was linked in the protein as a "clasp" within a single subunit and not between two subunits.

Amino Acid Sequence↗
PubMed1976

Comparison of the amino acid sequence of pig heart myoglobin with other ungulate myoglobins.

The primary structure of pig heart myoglobin has been established by study of the tryptic peptides of whole globin and by analysis of the fragments obtained by CNBr cleavage. Thermolysin and chymotrypsin digestion were used to determine the sequence of the M fragment (56-131). Automatic Edman degradation of whole globin and of the M fragment completed the sequence of pig myoglobin. Comparison with other ungulates shows that pig myoglobin is far from other artiodactyls previously studied (ox and sheep) and close to the eutherian ancestral chain.

Amino Acid Sequence↗