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Biomedical subjects

G Faure

Publications and source records attributed to G Faure.

At least 163 records · Page 9Linked to original sources

Improvement of cellular immunity and IgA production in immunodeficient children after treatment with synthetic serum thymic factor (FTS).

Three children with IgA and IgE deficiency and T-cell defects (two related patients with ataxia telangiectasia and one with common variable immune deficiency) were treated with synthetic serum thymic factor (FTS) intravenously. A reduction in frequency and severity of infection was noted concomitantly with improvement in cell-mediated-immunity tests. Serum IgA, which was absent in two patients, appeared within 4 weeks of treatment and increased significantly in the third patient. Specific antibodies against vaccination antigens appeared for the first time or increased to titres higher than ever before. In two patients, transient interruption of FTS administration was followed by a regression of the immunological improvement, but this disappeared after the treatment was started again.

Adolescent↗

Neutralizing monoclonal antibody specific for Naja nigricollis toxin alpha: preparation, characterization, and localization of the antigenic binding site.

One homogeneous population of high-affinity monoclonal antibodies (KD = 0.35 nM) specific for Naja nigricollis toxin alpha has been produced. It neutralizes the biological activity of the toxin under both the vivo and in vitro conditions. The molecular zone of the toxin to which the antibody binds has been precisely defined on the basis of cross-reaction experiments using five derivative of toxin alpha monomodified at a single amino group and two naturally occurring homologous toxins. The epitope is located at the base of the first beta-sheet loop of the toxin, involving the two positive charges at the N-terminal position and lysine-15 proline-18, and probably threonine-16. It is shown that this region is topographically distinct from the "toxic" site of toxin alpha. Several possibilities are offered to explain the mechanisms(s) of specific neutralization.

Animals↗

[T-lymphocyte subpopulations in chronic inflammatory rheumatism].

Monoclonal antibodies to a series of human lymphocytes subpopulations antigens (OKT) specific of the peripheral T cells (OKT3), of the inducer population (OKT4) of the suppressor cytotoxic population (OKT 5, OKT8), and anti-Ia (OKI1) were used to study blood lymphocytes from 50 patients with active or inactive rheumatoid arthritis (RA) and from 23 patients with ankylosing spondylitis (AS). In RA patients, there is a significant decrease of the total T cell population (T3 +) with higher percentages of helper (T4 +) T cells than in controls. In active forms of the disease, there also is a decrease in the suppressor cytotoxic (T5 + and T8 +) subset with a significant increase of the immunoregulating ratios T4 +/T5 + or T4 +/T8 +. Elevated levels of Ia + lymphocytes are found in all RA patients. Corticosteroid treatment seems to erase these abnormalities. On the contrary in AS patients, no significant modification of the T cell populations was evidenced.

Antibodies, Monoclonal↗

Inflammatory effect of aluminium phosphate on rat paws.

The aim of this experiment was to determine the inflammatory effect of aluminium phosphate on the rat paw and to compare it with those of carrageenan, calcium hydrogen phosphate dihydrate and natural diamond powder. At the probability threshold of the various tests used there was a significant increase in volume of the treated paw relative to the control paw for all the substances at all times, except for the two concentrations of diamond (effect no longer significant from 30 min on), of calcium phosphate (not significant from 2 h), and of aluminium phosphate (not significant from 24 h). The effects were not significantly different between diamond and calcium phosphate (both concentrations). The effects of aluminium phosphate were significantly different from those of the two until at least 2 h after the injection ; there was no significant difference between the two doses of this substance. The kinetics of the effects produced by carrageenan differed from the kinetics of the other materials, its effects were not significantly different from those produced by aluminium phosphate until 2 h and later. The inflammatory effect that we have demonstrated in this study is added information suggesting that in addition to apatite, calcium pyrophosphate dihydrate, and sodium monourate, aluminium compounds can play a role in the unexpected appearance of inflammatory manifestations in haemodialysed patients with chronic renal insufficiency treated with aluminium gels.

Aluminum Compounds↗

IgA nephropathy: characterization of the polymeric nature of mesangial deposits by in vitro binding of free secretory component.

IgA nephropathy, as Berger defined it, is characterized by mesangial deposits of IgA, which are easily visualized by immunofluorescence on kidney biopsies. The structure (mono- or dimeric) of these IgA has not been clearly defined so far. Fifteen renal biopsies were studied to find out whether these IgA are serum monomers, or are polymers from a different origin. This was done by tissue fixation in vitro of free secretory component, which was then visualized by immunofluorescence (IF). In all 15 cases, the IgA deposits were shown to lack bound secretory component, but were able to bind, specifically, with the free secretory component. The presence of J chain in these deposits was also evidenced by indirect IF. These findings favour the hypothesis that these immunoglobulins are polymeric.

Fluorescent Antibody Technique↗

In vitro induction of monoclonal antibody-defined T-cell markers in lymphocytes from immunodeficient children by synthetic serum thymic factor (FTS).

Lymphocytes from five children suffering from ataxia telangectasia or various unclassified immune deficiencies were tested in vitro for their sensitivity to synthetic serum thymic factor (FTS). The percentages of cells bearing T cell markers were elevated after incubation with FTS at graded concentrations (0.25, 2.5 and 25 ng/ml), by microlymphocytotoxicity or indirect immunofluorescence, using monoclonal anti-Lyt1 antibodies. In four cases, more than 30% of the non-T non-B cells acquired the Lyt1 T cell marker. These four children had low levels of circulating FTS. In the fifth child, who had a normal serum FTS level, and in two age-matched controls, there was no significant increase in the percentage of cells bearing the T marker.

Adolescent↗

[Protein binding of salicylates in rheumatoid arthritis].

Protein binding of salicylates was determined in 16 control subjects and 27 patients suffering from rheumatoid arthritis. Results obtained after separation of the free and bound fractions by dialysis to equilibrium and measured by spectrofluorometry were analyzed using a new mathematical model. In correlation with the decrease in plasma albumin concentrations, a decrease was found in the protein binding of salicylates in patients with rheumatoid arthritis. This phenomenon was less marked in therapeutic zones and was related to the degree of severity of the inflammatory syndrome. The binding capacity per albumin molecule at saturation was decreased in patients suffering from advanced forms, suggesting that the changes seen were not due solely to quantitative variations in serum albumin levels. This study confirms the value of the determination of free salicylate levels in patients suffering from inflammatory rheumatic disorders.

Adolescent↗

Apatites in heterotopic calcifications.

Calcified material obtained from three patients suffering from calcifications of the shoulder tendon sheath and from a subcutaneous with calcinosis was studied. A panel of different techniques was applied to this study: scanning electron microscopy, X-ray diffraction, infrared spectrometry, scanning and transmission wavelength dispersive X-ray spectrometry, high resolution transmission electron microscopy and electron microdiffraction. These calcifications, made of carbonate containing apatite, are heterogeneous and composed of at least two separate phases the crystallinity of which appear different.

Apatites↗

Increased pyrophosphate in fibroblasts and lymphoblasts from patients with hereditary diffuse articular chondrocalcinosis.

The metabolic and genetic factors leading to deposition of calcium pyrophosphate crystals in cartilage of patients with chondrocalcinosis are not well understood. Analysis of cultured fibroblasts and lymphoblasts from 12 affected members of a large kindred showed a mean concentration of intracellular inorganic pyrophosphate two times greater than that in cells from unaffected family members or normal, unrelated volunteers. Increased intracellular pyrophosphate may, therefore, be a biochemical marker for the heterozygous expression of the chondrocalcinosis gene.

Cells, Cultured↗