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Biomedical subjects

G Cordier

Publications and source records attributed to G Cordier.

At least 73 records · Page 4Linked to original sources

[Epidemic of listeriosis in Western France (1975--1976)].

Cases of human listeriosis have recently increased in Western France (Maine-et-Loire and Mayenne); until 1974, there were only 15 documented cases yearly where as in 1975, there were 113 cases, and in 1976, 54 documented cases at the hospitals of Angers and Laval. Included amongst the clinical manifestations observed, were 126 cases of materno-fetal infections and 41 cases of either septicemia or meningo-encephalitis. The bacteriological study revealed a certain variability of biological characteristics examined, the overwhelming frequence of bacteria of the strain 4 b and the predictable sensitivity of this strain to antibiotics commonly employed in cases of listeriosis. The human cases were notably more frequent between January and June but their geographical distribution was not related to cases of either animal disease nor listeria that was isolated from corn silage. In this report, we propose an etio-pathological explanation for this epidemic.

Adult↗

Contribution of lymphocytes bearing Fcgamma receptors to PHA-induced cytotoxicity.

Lymphocytes participating in PHA-induced lysis of chicken erythrocytes were characterized by means of cell fractionation methods. Selective depletion of, or enrichment in, E-rosetting cells indicated that the effector cell population was heterogenous, consisting of both T and non-T lymphocytes. Most effector cells, however, were shown to bear Fcgamma receptors detected by the formation of erythrocyte-antibody (EA) rosettes, but to lack C3 receptors. This distribution of effector cells among tonsils, peripheral blood and thoracic duct lymph paralleled that of EA-rosette forming cells but not that of T or B cells. Addition of aggregated IgG resulted in a moderate decrease of PHA cytotoxicity. However, almost complete inhibition was achieved within a few hours of contact between effectors cells and insoluble immune complexes. The results support the hypothesis that cytotoxic capacity is associated with the presence of Fcgamma receptors on the cell surface.

Binding Sites↗

[Liquid scintillation counting of 51chromium. Application to a micromethod of cell-mediated cytotoxic assay (author's transl)].

Detection of gamma emitting isotopes is achieved conventionally by using a gamma spectrometer, or in some cases by liquid scintillation counting. We applied these two methods to the detection of 51 Chromium released in a lymphocyte-mediated cytotoxic reaction. Detection in liquid scintillation appeared more efficient than conventional gamma detection: 16.74% vs 1,11%. It is therefore possible to reduce by a factor of 10 the number of target cells in the cytotoxic assay if liquid scintillation counting is used. Either method gave the same results when applied on the same samples. Liquid scintillation counting is to be preferred when high sensitivity is needed. In addition it offers the advantage of using the same apparatus for detection of gamma or beta emitting isotopes.

Chromium Radioisotopes↗

Antibody-dependent cell cytoxicity (ADCC). Characterization of 'killer' cells in human lymphoid organs.

The effector cell(s) in human antibody-dependent cell cytotoxicity (ADCC), with antibody-coated chickens erythrocytes as targets, was studied by comparison of cell suspensions from various lymphoid organs and by means of various cell fractionation methods. Effector cells (K) were found mostly in peripheral blood, spleen, and bone marrow but not in tonsils, lymph nodes, and thymus. Effector cells bear Fc receptors and can form EA rosettes with the antibody-coated target cells. About 1,5% peripheral blood lymphocytes can form 'high-avidity' EA rosettes with targets coated at low antiserum concentration. Most of the effector cells belong to this small subset, as shown by experiments of selective depletion. Removal of most monocytes, T cells, or B cells from, or addition of T-cell-specific antiserum to, the effector cell suspensions did not affect ADCC. Effector cells in this model of ADCC therefore lack the conventional B- or T-cell markers but at least some of them are likely to bear C3 receptors.

Antibodies↗