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Biomedical subjects

H Collet

Publications and source records attributed to H Collet.

34 records · Page 2Linked to original sources
PubMed1981

Beneficial effects of oral zinc supplementation on the immune response of old people.

Zinc is known to have beneficial effects on the immune response. In an attempt to modify age-associated immune dysfunction, supplemental zinc was administered to 15 subjects over 70 years of age (220 mg zinc sulfate twice daily for a month). As compared to 15 controls, matched for age and sex, there was a significant improvement in the following immune parameters in the treated group: (1) number of circulating T lymphocytes; (2) delayed cutaneous hypersensitivity reactions to purified protein derivative, Candidin and streptokinase-streptodornase; (3) immunoglobulin G (IgG) antibody response to tetanus vaccine. Zinc treatment had no influence on the number of total circulating leukocytes or lymphocytes, or on the in vitro lymphocyte response to three mitogens: phytohemagglutinin (PHA), concanavalin A (Con A) and pokeweed mitogen (PWM). The data suggest that the addition of zinc to the diet of old persons could be an effective and simple way to improve their immune function.

Adult↗
PubMed1980

In vitro response of human peripheral blood lymphocytes of protein A. DNA synthesis and generation of cells synthesizing the three major classes of Ig.

Increased DNA synthesis and immunoglobulin secretion was observed in human peripheral blood lymphocytes (PBL) cultured in vitro with soluble protein A from Staphylococcus aureus (Sp-A). Optimal Ig secretion was obtained in 6 day cultures containing 1 x 10(6) cells/ml and 10 microgram/ml Sp-A. The presence of 5 x 10(-5) M 2-mercaptoethanol in the culture medium as well as careful selection of foetal calf serum were needed for optimal results. In response to Sp-A stimulation, the three main classes of immunoglobulins were secreted by PBL. In some individuals, concentration of Sp-A optimal for IgG and IgM secretion inhibited IgA production. Immunoglobulin-containing cells were less abundant (0.5--5% of total cells) and smaller in Sp-A than in PWM-stimulated cultures (5--15%). The data suggest that Sp-A and PWM stimulated different subsets of circulating lymphocytes.

Cells, Cultured↗
PubMed1979

Distribution of beta-adrenergic receptors on human lymphocyte subpopulations.

A technique is described allowing the quantification and the characterization of specific beta-adrenergic receptors in intact living human lymphocytes. 125I-Iodohydroxybenzylpindolol, a potent beta-adrenergic antagonist was used to label specific binding sites on unfractionated lymphoid cells and on purified subpopulations of T (F1 and F2) and B cells. F1 and F2 were obtained by filtration through nylon wool column as previously described (Delespesse et al., 1976), they differ in their response to mitogens, and in their interactions with adherent cells and B cells. 125I-HYP binding to unfractionated lymphocytes was a saturable, stereospecific and rapid process with a dissociation constant of 2.5 10(-10) M and a binding capacity of 400--600 sites/cell. Bindings on unfractionated lymphocytes, purified B cells and T cells of the F2 fraction were similar. No detectable binding was noted on T cells from the F1 fraction. Enriched T cells obtained by a rosetting technique displayed 200 receptors/cell.

Adrenergic beta-Agonists↗
PubMedDate not supplied

Modulation of class II histocompatibility antigen expression by maternal serum.

Human maternal serum has been shown to down-regulate the expression of MHC class II antigen in three distinct circumstances. Cord blood mononuclear cells, incubated in the mother's own serum, showed significant modulation of class II antigen expression. This was also the case for unrelated donor lymphocytes, incubated in pooled maternal serum. One neoplastic line (Daudi) was further shown to down-regulate class II antigen expression. In this last case, the down-regulating effect persisted over a 10-day period during which maternal serum was renewed regularly. Retroplacental serum was more MHC class II-inhibiting than peripheral serum. This down-regulating effect does not apply to maternal lymphocytes. The inhibitory effect is thought to be due to a factor, yet to be defined, included in the maternal IgG fraction. Regular assays made throughout pregnancy showed that the class II inhibiting component appears early (5th week), reaches its peak value at the 12th week, and disappears 2 or 3 weeks after delivery.

Antigen-Antibody Complex↗
PubMedDate not supplied

[Computed gamma-tomographic estimation of a hepatic weight index during liver regeneration].

Single photon emission computed tomography was used to evaluate the total functioning liver mass and the regeneration process after partial hepatectomy. Serial tomographic sections were performed after infusion of 99m Technetium. In studies on dogs and in human beings, computed gammatomography enabled to calculate the liver mass with less than 10 p. 100 error. Hepatic regeneration was studied in 10 patients following resection of 46 to 84 p. 100 of the initial liver mass. The remaining liver mass increased rapidly postoperatively and doubled within 13 to 18 days. The regeneration process followed an exponential curve. Assessment of liver regeneration by this non-invasive technique should be of great help following partial hepatectomy.

Adult↗