Comptes rendus des seances de l'Academie des sciences. Serie D, Sciences naturelles最新文献

A minority among the prototrophic clones formed when protoplasts from two polyauxotrophic strains of B. subtilis are fused has been shown to be diploid, carrying the parental deficient alleles in their DNA, and generally segregating auxotrophs when grown in nutrient medium. This is true whether the strains being fused are Rec+ or Rec-, since the rec- mutations used hardly affect recombinations occurring between chromosomes in diploid Bacteria.

Human embryonic cell cultures, infected with the Mouse sarcoma virus, complex (Moloney isolate), produced a virus that specifically transformed mink lung cells. The non-transforming helper virus could infect Mouse cells as well as a wide range of other mammalian cells. These observations could suggest the presence of either several viruses in the virus stock and/or stable recombinants.

Testosterone (T) could be detected by immunocytochemistry after cryoultramicrotomy and T is likely bound on a binding site of a high affinity. Castration and adrenalectomy involve a swift disappearance of T in the gonadotropic cells. Synthesis of new binding sites was induced by daily T injection in the castrated and surrenalectomized Rat from 90 days. This synthesis is inhibited by cycloheximide. These data suggest that binding sites are proteins. The captation of T by the gonadotropic cells was diminished similarly at the diminution of T, afterwards, T captation was stabilized at a weak level which became stable for several weeks. It seems that immunocytochemistry permits the study of the variation of T captation by Rat pituitary gonadotropic cells.

The authors present an improved technique for operative treatment of tetralogy of Fallot. Developed by Edmund's technique it complets and improves it in several ways making it suitable for nearly all forms of tetralogy of Fallot. The transatrial approach is intended by it's author to only selected cases of the malformation, namely with large pulmonary arteries a correct pulmonary annulus and moderate infundibular hypertrophy. The combined approach which we propose (transatrial and transpulmonary) gives us very good post-operative and short term results.

A method for the purification of alpha-amylase from Bovine pancreas homogenate is described. This enzyme has the same molecular weight as the Porcine isoenzymes but its isoelectric point is more basic. Its amino acid composition is similar to that of Porcine, Ovine, Rat and Mouse amylases.

Tissue from 5 human malignant melanomas was surgically grafted into 39 athymic mice, 20 on lombar muscles covered by their aponevrosis, 13 on the intraperitoneal surface of the abdominal wall, 6 between the dorsal muscles and rib cage. These encapsulated, non-infiltrating, non-destructive tumours were clinically, macroscopically and histologically benign, but cytologically they have a malignant aspect. These were no perceptible visceral, cutaneous or muscular metastases. It would seem that a phenomenon of loosing of invasivness and destruction appeared. However further studies with other tumours and different experimental conditions will be needed to confirm the existence of this phenomenon.

The M1 pyruvate kinase has been localized in macroneuron's cytoplasm of nervous tissue of adult Rat, in situ as well as in tissue culture. Three methods have been used: histoenzymology, immunoenzymology and immunofluorescence, combined with Nomarski optics. This enzymatic localization may suggest a metabolic or differenciated fonctionnal state of the nerve cell.

Six alpha-adrenoceptor blocking agents have been investigated in dogs and rats. 170 150 and 170 153 have been found the most potent of these agents. At low doses (0,1 microgram/kg) they reversed the pressor response to low doses of adrenaline (0,1 and 0,3 microgram/kg) and suppressed the response to high doses of adrenaline. They reduced the pressor response to noradrenaline. In addition, in dogs 170 150 increased the tachycardia caused by stimulation of the cardiac nerve. The compound prevented and reversed the inhibition caused by clonidine on the effects of cardiac nerve stimulation. 170 153 did not increase the tachycardia caused by cardiac nerve stimulation, but it prevented and reversed the inhibitory effects of clonidine on this stimulation. The results show that 170 150 and 170 153 are potent alpha-adrenoceptor blocking agents acting on both pre and post-synaptic alpha-adrenoceptors which could be interesting pharmacological tools.

Specific receptor sites for the chemotactic peptide F-Met-Leu-Phe had been demonstrated on polymorphonuclear leucocytes isolated from Rats presenting, or not, an acute inflammatory reaction. A significant decrease of the chemotactic responsiveness of inflammatory cells had been measured by two different methods of assessment performed in parallel. This phenomenon is not related to a loss of peptide binding sites but an increase of adhesiveness would be implied in this mechanism.

In the isolated Rabbit heart, high pressure, on the one hand, inhibits the noradrenaline release, and on the other hand, induces both the biosynthesis and release of PGs(PGE2,PGF2 alpha) from the auricles and mainly from the right auricle i.e. where the sympathetic nerve endings are the most numerous. Therefore, high pressure, by a negative feedback process, plays a great part in moderating the adrenergic neurotransmission responsible for the hypertension. These effects result from a supplementary pressure which acts on the walls of coronary arteries and arterioles and modifies their distensibility. It thus appears that in the walls of arteries and arterioles there are baroreceptors which are sensitive to the pressure variations in order to regulate adrenergic neurotransmission, by means of a reflex path still unknown.