Comptes rendus des seances de l'Academie des sciences. Serie III, Sciences de la vie最新文献

19 antibodies specific for 11 different drugs were extensively tested in the presence of the drug against a panel of red cells including common and public minus phenotypes. High incidence blood group antigens were shown to be specific receptors for several drug-antibody complexes proving thereby that red blood cells play more than an "innocent bystander" role in drug induced immune hemolytic anemias.

Kinetics and family transmission of antigen specific immune responses were investigated before and 7, 30 and 120 days after booster immunization with tetanus toxoid (TT) in 73 individuals from 12 families. The study of TT specific in vitro lymphocyte proliferative response and of TT antibody levels by radioimmunoassay were performed in parallel; the effect of booster immunization was detectable 7 and 30 days later and still 120 days later for antibody response. No influence of the sex of donors was found. Because of the significant influence on the level of responses of the time interval since last immunization, data were correspondingly adjusted for segregation and linkage analysis. Observations at day 30 were compatible with the hypothesis of control by a dominant genetic determinant for high proliferative responses closely linked to the major histocompatibility complex region.

We have studied the in vitro malignant progression of human lymphoid cells by the combined effect of genetic, viral and mutagenic factors. A lymphoblastoid cell line immortalized by Epstein-Barr virus was used; it was derived from a patient suffering from ataxia-telangiectasia, a genetic disease linked to a deficiency in DNA repair. Cells were treated by sub-toxic doses of two potent mutagens (carcinogens), NQO (4-nitroquinolein-oxid) and R 7 000 (2-nitro-7-methoxy-naphto-furan). The treated cells showed an increased ability to form colonies in soft agarose, among which some compact colonies appeared, different from the diffuse colonies formed by untreated control cells. Sub-clones derived from these compact colonies differ also from the original cells by their behavior in liquid culture medium, by their increased tumorigenicity in Nude Mice and by their capacity to form nodules on Chicken chorioallantoic membrane. Some of the sub-clones produce non-regressing large tumors in Nude Mice with a cell inoculum lower than that required for Burkitt lymphoma cells while being less invasive than the latter. However, by their morphology, the malignant cells of the sub-clones remain similar to the original lymphoblastoid cells. Thus, such a malignant progression obtained in vitro cannot be considered as identical to that which leads to Burkitt lymphoma in African children.

A 431 nucleotide sequence from the central break region of Drosophila 26S rRNA precursor has been established by sequencing the corresponding region of the 26S gene. The analysis of rDNA-mature 26S rRNA hybrids submitted to S1 nuclease digestion has allowed us to show that a 75 +/- 3 nucleotide A-U rich RNA fragment is excised during the processing of the precursor.

The existence of UDP-galactose:galactosyltransferase activities at the external surface of cultured neurons from chick embryo hemispheres, was demonstrated. [14C]-galactose was transferred upon cellular substrates present on the neuronal surface and upon exogenous substrates (ovomucoïd) bound to Sepharose beads. The activity of ectogalactosyltransferase was not due to a leakage of intracellular enzymes into the incubation medium nor to an intracellular enzymatic activity utilizing [14C]-galactose obtained from the hydrolysis of UDP-[14C]-galactose. Kinetics of these ectogalactosyltransferases were analysed. The results support the hypothesis of a communication and/or interaction among the nerve cell surfaces via glycoconjugates or their biosynthetic enzymes.

The common marine Mussel Mytilus edulis, present in an uranium containing sea water at trace level, is shown to concentrate the radionuclide which is detected, with high values, in the digestive gland lysosomes and in the kidney spherocrystals. Within both of these target organelles, uranium is always associated with high phosphorus contents, with which low iron, sulfur, zinc and copper contents may be found. Thus, soluble uranium which was absorbed is then concentrated in the form of an insoluble phosphate in the storage organelles.

Streptococcus pneumoniae can be transformed by DNA. Transformation occurs in a transitory physiological state called competence. We observed a modulation of the Vi of aminoacid uptakes which seems selectively related to the energy coupling of the corresponding transports.

The treatment of human polymorphonuclear cells by neuraminidase "type-X" removes about 15% of cell sialic acid without modifications of NADPH oxidase activity of granulocytes before and after stimulation by opsonized zymosan. A mild periodate treatment oxidizes only the poly-hydroxilic chain of sialic acid with formation of aldehyde groups. This treatment increases cellular NADPH oxidase activity and also largely prevents the stimulation of polymorphonuclear cells by opsonized zymosan.

Somatocrinin (hp-GRF-44), a growth hormone releasing factor, stimulates acute pituitary response in a 11 years and 4 months old boy, with growth hormone deficiency. The capability of the anterior pituitary to secrete growth hormone in response to an IV injection of somatocrinin (120 micrograms 4 micrograms/kg) was documented, therefore proving the hypothalamic origin of the deficit which had been suspected because of association of diabetes insipidus and hyperprolactinemia.

Estradiol 17 beta concentration and cytoplasmic estradiol binding sites were determined in the magnum of immature and developing female Quail. In the immature magnum, estradiol concentration per gram of tissue was 26 times higher than in the plasma. Early sexual development was correlated with an increase in plasma and magnum concentrations of estradiol and of cytoplasmic binding sites in the magnum. However, the ratio of binding sites concentration to that of intra-tissue of estradiol, and the intracellular distribution of estradiol (cytoplasm versus nucleus) were similar in immature and developing Quail. The results indicate that the presence of estradiol and of binding sites in the target cells of the magnum are not sufficient to induce cell proliferation.