Devant une azoospermie ou une oligozoospermie extrême: ICSI ou IAD?

Intra-cytoplasmic sperm injection (ICSI) allows to obtain evolutive embryos even in case of extreme oligozoospermia: this technique must thereby be proposed to couples before considering artificial insemination with donor semen (AID). Azoospermia sets some specific problems, particularly in case of deep alteration of spermatogenesis except in rare seminiferous tubules. There is a high risk of ICSI failure because of absence of spermatozoa extracted from testicular biopsies. AID represents therefore a much less heavy solution. In every cases, the opinion of the couple is very important to take in account.     

Point isoélectrique ou zones de labilité colloïdale?

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Flagellés incolores rares ou nouveaux

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L'escargot ou les difficultés de l'hermaphrodisme

Summary

The article summarizes the research carried out in Besançon on the stylommatophoran snail Helix aspersa, a pulmonate gastropod mollusc.

The influence that external factors like photoperiod and temperature have on growth and reproduction was studied in this animal. The obtained results made possible a great development of snail breeding.

The potentialities of the hermaphroditism emerge from the observations made on the ovotestis: differentiation and development of the different cell types, presence of fibronectin, richness in neuropeptides, existence of male and female steroids, vitellogenesis processes.

In vivo experiments as well as in vitro cultures demonstrated the involvement of the cerebral complex in the control of reproduction. The dorsal bodies (DB)—(it consists of scattered cells)—stimulate the growth of the oocytes. The DB are under an inhibitory nervous control of the cerebral green cells (CGC); the FMRF-amide might be involved in this process.

A map of the neurons of the cerebral complex has been prepared. It shows the presence and the diversity of neuropeptides. Attention was focused on met-enkephalin and somatostatin. This later peptide seems to be involved in the shell growth. The active molecule, which was isolated from hemolymph and digestive gland is structurally quite similar to vertebrate somatostatin.

The results are compared with those obtained in other molluscs, especially in basommatophora. They reveal that the biological phenomena observed in the snail model are included in the fundamental processes, known in other invertebrates or vertebrates.     

Quelques Diatomées rares ou nouvelles de France

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Note sur quelques Diatomées rares ou nouvelles

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L’éclairage biologique des activités mentales: réduction ou mise en perspective ?

The relationship between the human psychological faculties and their underlying biological foundation is traditionally addressed within the mind-matter philosophical framework and its ethical extension regarding freedom and determinism. Neurobiology represents a new method, reflective of our times, to articulate the relationships between biological and psychological phenomena. The various points of view in this field are often based on implicit ontological presuppositions and, at least sometimes, unconscious epistemological assumptions: monism vs dualism, functionalism, reductionism, eliminativism, type identity and other more or less sophisticated variations. Bearing in mind the pitfalls these create, we can try to determine structural analogies across the different levels of the living being and the mind: the energy imbalance maintained for cell survival; the dynamic and complementary relationship between homeostatic and allostatic functions in living organisms; the tension between essential and complementary cognitive brain processes, such as the processes used to represent an object and those used to locate an object in space. Those phenomena all bear structural analogies, even though they work at different levels.     

Fertilité et aneuploïdies spermatiques après traitement par radiothérapie et/ou chimiothérapie pour cancer du testicule ou lymphome

Improvements in cancer therapy have considerably modified patient survival rates over recent years. However, the side effects of these treatments especially the effects on fertility, must be taken into account. Anticancer therapy can transiently inhibit spermatogenesis. Factors such as pretreatment semen parameters and the type of chemotherapy or radiotherapy may influence recovery of spermatogenesis, but it is still impossible to predict the probability of and time to recovery for each patient. Sperm banking remains the only way to prevent the effects of cancer treatment on male fertility. Another possible effect of chemotherapy or radiotherapy is genetic damage to germ cells. For instance, chromosomal abnormalities in viable sperm produced by these patients after recovery of spermatogenesis may result in fetal death or congenital abnormalities in their offspring. It has been fairly well documented that, during the first three months after treatment, DNA breaks and abnormal chromosomal segregation induced by chemotherapy/radiotherapy lead to structural and numerical chromosomal abnormalities in spermatozoa, respectively. However, the long-term effects on genetic sperm content have not been clearly established. The results of published studies are contradictory and are based on limited numbers of patients (maximum of 6). We present the preliminary results of a retrospective study concerning patients treated for testicular cancer or lymphoma between 1995 and 2000. Fluorescence in situ hybridization (FISH) analysis of chromosomes X, Y and 18 was performed on sperm collected one to five years after treatment and compared to the data obtained for non-affected fertile men. For four out of 13 patients, we found a significantly increased frequency of aneuploidy rates (mainly XY disomy and diploidy), and these results did not appear to be correlated with sperm count, sperm morphology or post-treatment duration. In conclusion, increased sperm aneuploidy rates appear to only concern a small number of patients, to varying degrees and without any predictive factors. According to published data and our preliminary results, we recommend waiting at least two years before starting ART (Assisted Reproduction Therapy) for patients treated for testicular cancer or lymphoma. Moreover, FISH analysis could be helpful to choose between ART with post-treatment sperm or cryopreserved sperm.     

L'acide ascorbique ou vitamine C dans la cellule et sa détection

Résumé La répartition si générale de l'acide ascorbique dans tous les éléments végétaux et animaux semble indiquer que ce corps joue un rôle général et fondamental. Mais cette répartition n'est pas homogène. Elle varie beaucoup avec les organes. Sa concentration si élective dans certaines cellules parait correspondre à des propriétés fonctionnelles communes à tous ces éléments.Histochimiquement on peut déceler l'acide ascorbique jusque dans la cellule où sa présence se localise au cytoplasma ou même à certains de ses organites: chondriome, appareil de Golgi.Sa mise en évidence y dépend de divers facteurs et en particulier de la présence d'autres substances qui bloquent son pouvoir réducteur: ce dernier fait n'est peut être pas sans importance physiologique.     

Quelques Algues rares ou nouvelles d'un Étang de Rambouillet (Ferme Nationale).

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