The effects of intraperitoneal adaptation to histamine on the anaphylactic shock in the guinea-pig

Résumé Les cobayes adaptés à l'histamine par voie intrapéritonéale sont protégés contre le choc anaphylactique. Les mécanismes périphériques de la résistance sont discutés.     

Contribution of germ-line cells to formation of the nurse chamber in egg follicles of nonpaedogenetic gall midges (Diptera,Cecidomyiidae)

Summary One of the nuclei present in the syncytial nurse chamber in nonpaedogenetic gall midges contains lamellae characteristic only of the germ-line cells. This finding indicates that the nurse chamber in bisexually reproducing gall midges, as in the case of paedogenetic species, derives from both germ-line and somatic cells.This investigation was supported in part under Contract DPKBN/52/76-II.1.3.10. with the Polish Academy of Sciences.     

The release of platelet factor 4 during platelet aggregation and the possible significance of this reaction in hemostasis

Résumé Nous avons constaté que le facteur plaquettaire 4 est libéré au début de l'aggrégation des plaquettes par l'ADP et l'adrénaline. Ce phénomène a pu être mis en évidence en étudiant l'activité antihéparinique et l'activité paracoagulante (coagulation non enzymatique de complexes solubles de monomères de fibrine) du facteur plaquettaire 4.     

Hypercoagulability and thrombocytopenia after platelet factor 4 infusion into rabbits

Résumé Le facteur plaquettaire 4 injecté aux lapins par la voie i.v. cause un abaissement rapide de taux de fibrinogène et de nombre de plaquettes, le racourcissement de temps de coagulation et l'augmentation de plaquettes adhésives.     

A pyruvate kinase variant in different mouse transplanted tumors

Summary Mouse transplanted tumors, in contrast to normal tissues, contain a pyruvate kinase (PK) variant sensitive to the inhibitory action of L-cysteine and less sensitive to saturated fatty acids than the normal enzyme. In selected normal and tumor materials two fractions of PK were separated. Fraction A (20–30% (NH₄)₂SO₄ saturation) dominated in normal liver, and fraction B (50–60% (NH₄)₂SO₄ saturation) in skeletal muscles and Ehrlich ascites tumor. Only this fraction B from tumor material was sensitive to L-cysteine, and seems to contain a tumor-specific PK variant which might be considered as a marker of neoplastic transformation in a broad spectrum of mouse experimental tumors.     

Juvenilizing effect of ecdysone mimic RH 5849 inGalleria mellonella larvae

The response of the final instar larvae ofG. mellonella to topical application of the non-steroidal ecdysone mimic, RH 5849, was age-related as well as dose-dependent. In young final instar larvae, moderate doses of RH 5849 induced perfect supernumerary larval moults, but doses equal to and higher than 8.5 μg per larva caused premature formation of larval cuticle and were lethal. Application of RH 5849 significantly increased allatotropic activity of the brain, and also activated synthesis of juvenile hormone (JH) by the corpora cardiaca/corpora allata complex. Simultaneous application of RH 5849 and FMev, a potent inhibitor of JH synthesis, to young final instar larvae lowered the incidence of perfect supernumerary larval moults. We conclude that the effect of RH 5849 on the developmental programme inG. mellonella is mediated by the corpora allata.     

Somatostatin inhibits the mitogenic effect of thyroliberin.

The effect of somatostatin and of thyroliberin on the mitotic incidence in the organ-cultured anterior pituitary lobe of the rat was investigated, using the colchicine metaphase-arrest technique. It was found that somatostatin added to the culture medium, together with thyroliberin, blocked the mitogenic effect of the latter.