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Biomedical subjects

M Fontaine

Publications and source records attributed to M Fontaine.

At least 145 records · Page 8Linked to original sources
PubMed1980

Effect of sialic acid removal on human low density lipoprotein catabolism in vivo.

This study was undertaken to determine whether sialic acid removal alters the catabolism of low density lipoprotein in humans. Human low density lipoproteins labeled in vitro with 125I were incubated in the presence (termed desialylated) or absence (sialylated) of neuraminidase. The treatment with neuraminidase from Clostridium perfringens removed 90% of the sialic acid residues which did not change the chemical composition of the lipoproteins. Sialylated or desialylated LDL were injected intravenously into normal human subjects. The mathematical analysis of the plasma radioactivity decay curves (followed for 220 h) of desialylated low density lipoproteins, when compared with sialylated LDL, showed a shorter mean transit time (51 h vs 60 h), a 52% faster metabolic catabolic rate and an increased volume of distribution. The data are consistent with a proposed metabolism of low density lipoproteins: in humans, desialylation appears to accelerate the first step of the low density lipoprotein conversion but not to alter its final catabolism.

Adult↗
PubMed1980

Preparation of an R3 reagent (serum depleted of the third component of human complement (C3)) by immunoadsorption. Application to the hemolytic assay of human C3.

We have devised a simple one-step preparation of C3 depleted serum (R3). Fresh normal human serum, with complement activation inhibitors, was depleted of C3 by affinity chromatography on a Sepharose anti-C3c. To prevent non-specific interactions, a high ionic strength buffer containing saccharose was used. Immunochemical analysis and complement activity assays demonstrate that this C3 depleted serum is a suitable R3 reagent. This R3 reagent has been used successfully for titration of hemolytic activity of C3 in normal and abnormal sera. Two simple, specific and sensitive assays are described.

Animals↗
PubMed1980

Experimental infection of calves with bovine respiratory syncytial virus (Quebec strain).

An experiment was designed to evaluate the clinical, haematological, viral and serological aspects of bovine respiratory syncytial virus infection in calves. Eleven calves were inoculated intranasally with bovine respiratory syncytial virus (Quebec strain) in aerosol. Clinical, haemotological and serological responses of the calves and virus shedding were monitored. The experimentally infected animals manifested moderate to severe signs of respiratory disease. The parameters used to evaluate the severity of the disease included ocular discharge, conjunctivitis, lung sounds, nasal discharge, pyrexia and leukopenia. The animals were scored accordingly (scale infected 70.8-148.5, control 22-29.3). Highest disease scores were observed between day 6-9 after infection. Virological and serological assessment demonstrated that the observed clinical picture was due to bovine respiratory syncytial virus infection.

Animals↗
PubMed1978

[Comparative study of cysteine peptides of monomers and polymers of IgA].

The cysteinyl peptides of monomeric and polymeric IgA were studied by comparative autoradiography. Autoradiographies of polymeric IgA (containing or lacking J chain) showed an extra cysteinyl peptide which was never found in the monomeric forms. A similar peptide was obtained when reduced IgA was cleaved by BrCN. The possible identity of this fragment is discussed.

Cysteine↗
PubMed1978

Relationship between the carbohydrate content of apoproteins of VLDL, IDL, and LDL and the plasma level of these lipoproteins in man. Short dietary effect.

A 1,500 Cal test meal was used to study in man the apoprotein B-carbohydrate content and composition of VLDL, IDL and LDL in relation to the variation of plasma lipids and lipoproteins and the VLDL-apoprotein composition. Three essential facts emerge from the study: (1) the mirror image (inverse significant correlation) between VLDL-apo B plasma concentration and N-acetylglucosamine content of apo B; (2) a reduction in total carbohydate concentration of VLDL- and LDL-apo B, 2--4 h after the test meal and a trend to a reduction in the mannose content; (3) a significant correlation between sialic acid and apoprotein B concentration in plasma LDL during fasting. The effect of diet and subsequent fasting on carbohydrates of lipoproteins and the consequence of such changes on lipoprotein uptake are briefly discussed.

Apoproteins↗