Évaluation des effets prosexuels des extraits de Bridelia ferruginea chez le rat mâle naïf

The stem barks and the leaves from Bridelia ferruginea (BF, Euphorbiaceae), a medicinal plant, are used in traditional medicine for the treatment of several ailments including male impotency. The present study was aimed at investigating the effects of the dried stem bark of BF on the sexual behaviour of normal and castrated sexually inexperienced male Wistar rats. Animals were orally administered with 100 mg/kg of either the aqueous or the ethanol extracts of BF whilst the neutral control group received in the same way 10 ml/kg of distilled water. The positive control group was treated with a subcutaneous injection of testosterone propionate (20 mg/kg/day/3days) prior to the experiment. The sexual behaviour of all rats was monitored on days 0, 1 and 7 by measuring frequencies of penile erection, mount, intromission and ejaculation. In a separate group of normal sexually inexperienced rats, the pro-sexual effects induced by a single dose of the aqueous extract (100 mg/kg) were measured after pre-treatment with either haloperidol (10 mg/kg), atropine (10 mg/kg) or L-omega-nitro-arginine methyl ester (Lω-NAME, 10 mg/kg). Results obtained showed a significant influence of the duration of treatment on the frequencies of penile erection, mount and intromission of both normal and castrated rats. An increase in all sexual performance parameters was observed when compared to respective controls. The intromission frequency of normal animals was significantly increased (P < 0.05–0.01) on day 1 of treatment and the effect was more expressed in rats receiving the aqueous extract. In castrated animals, a statistical increase was noticed on day 7 for rats treated with testosterone. The sexual effects induced by the aqueous extract of BF were completely abolished after pre-treatment of rats with atropine or haloperidol while pre-administration of Lω-NAME did not produce any significant effects. Flavonoids and sterols revealed in the aqueous and ethanolic extracts from the barks of BF may account for the enhancement of sexual activity in naive rats which could be expressed through dopaminergic and/or cholinergic receptor(s). Results of this work also give value to the traditional use of the plant for the improvement of male sexual behaviour.     

Anemia in experimental visceral leishmaniasis in hamsters.

Experimental infection of hamsters with Leishmania donovani caused visceral leishmaniasis in which hematological changes occurred. The infected hamsters were anemic and reticulocyte counts were high. No significant change in the serum erythropoietin level was noted. Red cell membrane Na(+)-K(+)-ATPase and acetylcholinesterase activities increased. Osmotic fragility of the erythrocytes from infected animals increased. The level of 2,3-diphosphoglycerate of the red cells increased with the degree of anemia.     

Nif-hybrids of Enterobacter: selection for nif gene integration with chlorate

The nif gene group from Klebsiella can be transferred into Enterobacter cloacae by conjugation using Escherichia coli donor cells carrying the composite self-transmissible nif-plasmid pRD1. A small fraction of the hybrids obtained is stable upon prolonged passaging without selection. Their stability is due to integration of pRD1 into the chromosome. Such integration hybrids were chlorate resistant, and nitrate reductase negative, which indicated that integration preferentially occurred within one of the genes for the production or functioning of this enzyme. Chlorate resistance could, therefore, be used to select for additional nitrate reductase-negative sublines with pRD1 in their chromosome. Such sublines have been analyzed further for the presence of nif genes, other pRD1 markers, and for stability. In all except one the complete plasmid seems to have been integrated. Some tend to revert to nitrate utilisation (chlorate sensitivity).