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Biomedical subjects

N Genetet

Publications and source records attributed to N Genetet.

At least 55 records · Page 3Linked to original sources
PubMed1986

Transmissibility of human immunodeficiency virus in haemophilic and non-haemophilic children living in a private school in France.

In a study of the transmissibility of human immunodeficiency virus (HIV) in haemophilic and non-haemophilic children living together in a boarding school in France, half of the haemophilic children had seroconverted by the end of a 3-year study period. By contrast none of the non-haemophilic children seroconverted. All children had had close casual contact, some of them for several years. Hepatitis B virus (HBV) markers detected in all polytransfused haemophiliacs were found in 4 of 20 control children in the school, whereas all healthy youngsters living with their families were HBV negative. This study adds support to the theory that transmissibility of HIV among casual contacts is low and that there is no reason to exclude HIV-antibody carriers from communities.

Acquired Immunodeficiency Syndrome↗
PubMed1986

T lymphocyte subsets at various stages of hyperthyroid Graves' disease: effect of carbimazole treatment and relationship with thyroid-stimulating antibody levels or HLA status.

Markers of autoimmunity in hyperthyroid Graves' disease were studied at various stages of the disease in connection with HLA status. The 148 patients studied were included in a long term prospective evaluation of antithyroid drug treatment. The proportions of total T lymphocytes and OKT4 and OKT8 positive cells in peripheral blood and circulating thyroid-stimulating antibodies were determined before treatment (M0; 46 patients), after 6 (M6; 50 patients), and 18 months (M18; 22 patients) of carbimazole treatment, at relapse (15 patients) and after 2 yr of euthyroidism after drug withdrawal (remission; 23 patients). Twenty-seven patients were sequentially studied between M0 and M6, and M6 and M18. As compared to matched normal subjects, the mean proportion of OKT8 positive cells was significantly decreased in every group of patients, even in those in remission, and the mean OKT4/OKT8 cell ratios were increased in all groups except the patients in remission. However, OKT4/OKT8 cell ratios in individual M0 patients were widely distributed, being normal in 50%. No correlation was found between the proportions of T cell subsets and thyroid-stimulating antibody values, and the two measures varied independently in patients studied sequentially. OKT8 lymphocyte subset was dependent on HLA status. In DR3-positive patients, the mean OKT4/OKT8 cell ratio was high at all stages of the study; in DR3-negative patients it decreased significantly at M18 and was normal in those patients who had a remission. However, in the DR3-positive and -negative groups of patients, the mean OKT4/OKT8 ratios at M0 and at relapse were similar. In conclusion, the proportions of circulating OKT8 positive lymphocytes reflect only poorly the activity of the immune abnormalities in Graves' disease, but do correlate with HLA-DR3 status.

Adolescent↗
PubMed1985

Acute myeloblastic leukemia with active tyrosine protein kinase.

High level of tyrosine protein kinase activity was found in a membrane fraction isolated from an acute myeloblastic leukemia, out of 24 leukemias of different origin investigated. The major substrate for tyrosine phosphorylation in vitro was a 58 kDA protein (p58). The phosphorylation proceeded actively at 0 degrees C and was strongly stimulated by Mn2+ ions. Comparison by partial proteolysis of the p58 with similar phosphoproteins from a T-lymphoma line (KE37) and from lectin stimulated lymphocytes showed high similarity. The possible role of the tyrosine kinase activity in this leukemia is discussed.

Gastrins↗
PubMed1984

Stimulation of tyrosine phosphorylation in lectin treated human lymphocytes.

Large increases in tyrosine phosphorylation have been detected in subcellular matrixes isolated from lectin treated human lymphocytes. In lectin stimulated cells proteins of molecular weight 105, 75, 58 and 35 kDa contained phosphotyrosine (P-tyr) whereas non-stimulated cells had no 105 and low levels of P-tyr in proteins of 75, 58 and 35 kDa. In stimulated cells increased tyrosine kinase activity was also shown using gastrin as substrate. In both stimulated and non-stimulated cells the 58 kDa phosphoprotein was the most heavily labelled, after partial proteolysis of the 58 kDa different phosphopeptides were generated. A peptide with a sequence analogous to the autophosphorylated tyrosine site of pp60src inhibited tyrosine phosphorylation in stimulated cells. The lymphocyte system provides a useful tool to study normal tyrosine protein kinases and their role in cellular proliferation.

Detergents↗
PubMed1983

Tyrosine phosphorylation in human T lymphoma cells.

A high level of tyrosine protein kinase (TPK) has been recently detected in the murine lymphoma LSTRA. The main substrate for tyrosine phosphorylation in this cell line is a Mr 55 000 protein associated with the insoluble matrix of the cell. These findings prompted the search for TPK activities in human lymphoid cells. Three human T lymphoma cell lines (i.e. Molt. 4, JM, and Ke 37) and control lymphocytes were examined. After in vitro phosphorylation of detergent insoluble extracts from human T lymphoma cells, 2 major phosphotyrosine containing proteins with Mr 55 000 and 35 000 can be detected in all three T lymphoma lines, whereas an additional species with Mr 78 000 is present only in the Ke 37 cell line. Similar size proteins are weakly phosphorylated in normal lymphocytes. Tyrosine phosphorylation in these proteins proceeds actively at 0 degrees C, and is dramatically stimulated by Mn++ ions. Partial proteolysis mappings of the Mr 55 000 phosphoproteins from murine and human lymphomas revealed a strong homology among these molecules. The function of this protein in transformed lymphocytes is discussed.

Animals↗
PubMed1983

[Peripheral distribution of lymphocyte subpopulations in Basedow's disease. Decrease in suppressor T-lymphocytes].

The distribution of B- and T-lymphocyte subpopulations was studied in peripheral blood of 45 patients with untreated Graves' disease and 45 sex- and age-matched healthy controls. Blood samples were taken at the same hour in all subjects. The following tests were performed: HTLA and E (AET) for relative T-lymphocyte count, complement receptor (EAC) and surface immunoglobulins (IgS, IgG, IgM, IgA, kappa, lambda) for relative B-lymphocyte count. In 23 subjects of each group the subpopulations of T-lymphocytes were defined by their reactivity with monoclonal antibodies OKT8 (T-suppressor cells) and OKT4 (T-helper cells). Compared with the control group, patients with Graves' disease showed a decrease in the number of T-lymphocytes (HTLA: P less than 0.05: EAET: P less than 0.001) a decrease in T-suppressor cells (P less than 0.01), and no significant difference in B-lymphocytes and T-helper cells. Thus, the main lymphocyte characteristic in Graves' disease is a decrease in the relative value of T-cells, specifically affecting T-suppressor cells.

Adult↗
PubMed1982

[Immunological changes following heart surgery under extracorporeal circulation (author's transl)].

Post-operative immunological changes were studied in 40 patients undergoing heart surgery. Tty-five patients were operated upon under extracorporeal circulation (ECC), and 15 without ECC. Immunological investigations were performed before, immediately after the operation and again 7 days later. The post-operative changes recorded were early decrease in IgG and IgM followed by a rise in IgM, transient lymphocytopenia affecting mainly T lymphocytes and delayed increase in complement (CH50, C2, C3). These changes were comparable in both groups of patients and therefore seemed to relate to the operation itself rather than to the ECC. It may be concluded that ECC does not appear to increase the risk of post-operative infection by depressing immune defence mechanisms.

Adolescent↗
PubMed1982

Allogeneic responses in vitro induced by fetomaternal alloimmunization.

The present study was undertaken in order to determine what type(s) of pregnancy-induced allogeneic reaction could alter MLC (mixed lymphocyte culture) reactivity in routine HLA-D typing of lymphocytes in multiparous women (MW) possessing antibodies against paternal HLA-DR antigens. Unresponsiveness to homozygous typing cells (HTC) representing a paternal and probably fetal HLA-DR determinant was frequently observed. Kinetics experiments ruled out an early secondary proliferative response to HTC representing the paternal HLA-D determinant, which would be missed in a classical long-term mixed lymphocyte culture. Direct cytotoxicity against paternal or panel target cells was not always associated with inhibition of proliferative response to the same stimulator cell. Specific anti-HLA-DR blocking activity (antibodies?) in the supernates of restimulation reactions of lymphocytes from MW could be responsible for this inhibitory effect. Moreover, the study points to the existence of suppressor cells in the immunized MW acting independently of specific restimulation. The in vitro suppression appeared to be selective, restricted to cells sharing HLA-D linked structures with the suppressor cells, and suggests that auto-regulator mechanisms could be induced in pregnancy in order to modulate antibody production.

Antibodies↗
PubMed1979

HLA determinants in idiopathic hemochromatosis.

HLA-A and B antigens were defined in 154 unrelated idiopathic hemochromatosis patients. The study confirmed the highly significant positive association with HLA antigens A3 (corrected P less than 10(-10)) and B14 (corrected P less than 10(-9)). HLA-DR typing showed increased frequency of the specificity DRw6, which was frequently associated with the phenotype A3, B14 and antigen B14, suggesting linkage disequilibrium. This was borne out by PLT data.

Epitopes↗
PubMed1976

[Major histocompatibility system in multiple sclerosis].

The comparison of Histocompatibility Testing in 82 MS Patients and 368 controls is presented. The increase in HL-A7 and decrease in HL-A12 are confirmed. A significant increase in HL-A8 is reported. Mixed Lymphocyte Reaction confirms the LD7a increase (19 out of 24 Multiple Sclerosis patients tested); 100% of the patients bearing the HL-A7 determinant are found to be LD7a. The presence of specific Immune Response genes in Multiple Sclerosis is discussed.

Histocompatibility Antigens↗
PubMed1975

[Determination of LD7a structures on human lymphocytes].

The non-stimulation of DNA synthesis in human lymphocytes in the one way mixed lymphocyte culture conditions allows the typing for LD determinants. The authors describe their technique together with their cryo-preservation procedure and the results obtained in 24 control population and 26 multiple sclerosis patients tested for the presence of the LD7a determinant.

Histocompatibility Antigens↗