Les néoblastes dans la régénération antérieure deDendrocoelum lacteum,Turbellarié triclade

Résumé Les néoblastes de la région postérieure du corps de la PlanaireD. lacteum ont les mêmes propriétés migratrices et histogénétiques que les néoblastes de la région prépharyngienne. En cas de section transversale à quelque niveau que ce soit, les néoblastes du fragment postérieur se déplacent d'arrière en avant pour s'accumuler en un bourgeon de régénération normal. Mais la différenciation de ces cellules ne se produit qu'en cas de section nettement antérieure à la racine du pharynx (alors il y a régénération). Après une section postérieure à la racine du pharynx, les néoblastes dégénèrent.

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Neoblasts in the anterior regeneration ofDendrocoelum lacteum, Turbellaria tricladida

Summary Neoblasts of the posterior region of the body in the PlanarianD. lacteum have the same migratory and histogenetic properties as neoblasts of the prepharyngeal region. With transverse cuts at whatever level, neoblasts of the posterior fragment migrate forward to accumulate as a normal regeneration bud. But differentiation of these cells only occurs in ease of a section clearly anterior to the root of the pharynx (regeneration then follows). After a transection posterior to this level, the neoblasts degenerate.

     

Sahelian woody vegetation in Sénégal

Structure and composition of woody vegetation in Sahelian forest types (not including riparian and riverine types) were studied in Sénégal. The application of classification and ordination resulted in the recognition of seven distinctive woody community types, related to soil and precipitation gradients. The described vegetation types only contained four strictly Saharan species, the rest being of Sahelian and Soudanean affinity, so a floristic change from savanna to desert vegetation after two decades of drought could not be confirmed. Tree density was lower in the northern part than earlier, possibly an indication of degradation. Rejuvenation was greatest at the northernmost arenosolic stations, but low in the southern, ferrouginous areas. This presumably demonstrates the resilience of North-Sahelian vegetation, at the moment being in a dynamic rejuvenation phase, after a period of adverse conditions.     

Spermatogénèse et Paraplégie

In this article, the paraplegics’ possibilities for procreation will be examined. A first chapter will deal with the testicle functioning along with the study of hormonal measuring and testicle histology (study involving 100 patients). As a result, it appears that, after a testicle biopsy, there is a testicle lesion of neurological origin that is sometimes irreversible. On the contrary, the endocrinal testicle lesions have proved reversible under stimulation or spontaneously. A second chapter will deal with the different techniques to obtain an ejaculation and the semen analysis. The techniques that were used being: massage by vibrator, electroejaculation, ejaculation through pharmacological stimulation. The study focuses on 124 ejaculatory tests among which 64 forward ejaculations (52%) and 4 bachward ejaculations (3%) were obtained. The resulting semen analysis revealed a spermatozoon count greater than 20 millions per millilitre (that is 51,5%) and smaller than 5 millions in 11 cases (16%).     

Chromosomes et hétérochromosomes de ténébrionidés

Sans résumé Avec 81 figures dans le texte     

Profil spermiologique de l’époux dans les couples infertiles en milieu négro-africain au Sénégal

Objective

To define the role of male infertility in black African couples in Senegal and to establish the semen profile.

Material and Methods

We analysed 17,459 sperm counts and 5,563 post-coital tests from patients consulting for primary or secondary infertility between January 1982 and December 2002. Negative and deficient sperm counts of post-coital tests were studied to demonstrate the responsibility of male infertility. For sperm counts, we studied the patient’s age, the mode of semen collection, the volume of ejaculate and semen characteristics.

Results

Primary sterility (68.4%) was twice as frequent as secondary sterility (31.6%). Male infertility (31.7%) was twice as frequent as female infertility (14.7%). Twenty eight per cent of patients presented hypospermia. Isolated oligozoospermia was observed in 10% of cases and azoospermia was detected in 23% of cases. Qualitative sperm changes were observed in 44.3% of cases. A positive semen culture was reported in 21.3% of cases. Combinations (qualitative sperm changes and abnormalities of number) were observed in 43.4% of cases. Oligo-astheno-teratozoospermia (OATS) with spermatozoa with an elongated head, cytoplasmic remnants and angulation, characteristic of varicocele was significantly more frequent in patients with varicocele (97% of men with right varicocele and 98.2% of men with bilateral varicocele). Reactive epididymosemino-prostatic dystrophy was observed in 11.9% of cases

Conclusion

Male infertility plays a real role. The semen profile of the husband of a sterile couple in Senegal is characterized by the importance of polymorphic alterations such as oligo-astheno-teratospermia and secretory azoospermia.