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Over the past ten years, knowledge regarding the origin of the oligodendrocyte lineage during development has increased considerably. In this review, we present the major findings as a result of which it was determined that only restricted regions of the neural tube have an oligodendrogenetic potential. These findings are based on the study of molecular markers permitting the detection, among the multipotent neutricular cells of the neural tube, of those with a potential to differentiate into oligodendrocytes. At the present time, it appears that these oligodendrocyte precursors can be distinguished in the brain either by the expression of the plp/dm-20 transcript, or by that of the alpha-receptor of PDGF. These two markers allow two oligodendroglial subpopulations to be differentiated, suggesting a multiple origin of oligodendrocytes. An assessment has also been made of the current state of knowledge, still incomplete, regarding the intrinsic and extrinsic factors which cause a multipotent cell strain to follow an oligodendroglial differentiation. A better knowledge of the oligodendrogenesis during embryonic development should provide insight into the regeneration mechanisms, and later to the development of therapeutic strategies aimed at increasing the endogenous potential of remyelinization.

La cinetique d'anesthesie de truites arc-en-ciel (Oncorhynchus mykiss) avec de l'Aqui'S® a ete suivie sur des animaux de differents poids (9, 25 et 200 g). La vitesse d'anesthesie augmente avec la dose d'Aqui'S® utilisee. Aucune mortalite n'a ete observee lorsque les concentrations utilisees sont inferieures a 60 ml/m3 d'eau pour une duree d'anesthesie inferieure a 30 min. La cinetique de reveil est egalement dose dependante. L'anesthesique a egalement ete teste avec succes sur des truites fario (Salmo trutta) de 190 g. L'anesthesie de truites arc-en-ciel dans le bassin d'elevage (sans peche des animaux) avec une concentration de 40 ml d'Aqui'S® /m3 d'eau ou dans un bac (apres une peche rapide des animaux) avec une concentration de 100 ml d'Aqui'S® /m3 d'eau ne provoque pas d'augmentation des concentrations plasmatiques de Cortisol par rapport a celles mesurees chez des animaux anesthesies avec une concentration de 1 l de 2-phenoxyethanol/m3 . Lors d'un transport de truites arc-en-ciel a une densite de 145 kg/m3 pendant 6 heures, l'addition d'Aqui'S® ou de 2-phenoxyethanol a l'eau des cuves permet d'avoir des animaux en legere sedation. Les concentrations plasmatiques de Cortisol sont significativement plus faibles que celles mesurees chez les animaux transportes sans anesthesique. Cependant, ces concentrations sont significativement superieures a celles des animaux restes dans le bassin d'elevage. Les animaux transportes sous sedation legere ont repris l'alimentation plus rapidement que les animaux non anesthesies. Ces travaux, bien que preliminaires, montrent que l'Aqui'S® permet d'obtenir le meme type d'anesthesie qu'avec le 2-phenoxyethanol pour un prix de revient legerement inferieur.

Hypoestrogenemia-derived urogenital symptoms after menopause manifest after some years of hormonal deficit and appear commonly in elderly, untreated women. In the urogenital tract low postmenopausal estrogen levels lead to vaginal irritation and dryness and to dyspareunia, often accompanied by other symptoms like uriesthesis, incontinence or recurrent infections. Every systemic estrogen treatment is accepted as efficient for the correction of urogenital symptoms, often even at doses lower than those necessary for the correction of vasomotor symptoms. Diverse local treatments have been proposed: estriol, promestriene and low-dose estrone or estradiol. Promestriene applied locally stimulates differentiation and maturation of vaginal mucosa and compensates local hypoestrogenic effects without marked hormonal effects outside the vagina. Vaginal application of estrone, on the other hand, has rather been proposed for systemic hormone substitution and elevated levels of estrone and estradiol observed in the plasma render this method in-appropriate in cases where strictly local effects are desired. Recently, very low doses of estradiol in a range of 7.5 micrograms/day have been proposed for the treatment of urogenital atrophy by means of a prolonged release regimen. Among the described preparations, those with strictly local (devoid of systemic) effects should be restricted to patients with contraindications for systemic substitution therapy. Local estrogen therapies are recommended for the treatment of complaints due to vulvar and vaginal atrophy. They have also been proposed by certain authors for the acceleration of the cervico-vaginal and vulvar cicatrisation after surgical interventions or postpartum. The presence of miction disorders in elderly postmenopausal women is also a point in favour of local treatment.

This open, randomized study on 2 parallel groups compared the acceptability, digestive tolerance and observance of TX 1341, a new chewable magnesium tablet (OROMAG, Laboratoire Théramex) to that of a reference magnesium (MAG2, Laboratoire Théraplix). 179 patients warranting a magnesotherapy were treated for 10 weeks either by 3 chewable lactate and citrate of magnesium tablets (TX 1341) each containing 120 mg of magnesium-element, or by 3 drinkable ampoules of pidolate of magnesium (each of 122 mg of magnesium-element). Acceptability was assessed at the end of the study by a semi-quantitative scale at four levels and digestive tolerance by closed questionnaire submitted before and after treatment. 72.7% of patients treated by TX 1341 find the treatment agreeable against 46.1% with the reference magnesium (p0.01). The number of drops out linked to treatment is not significantly different in the two groups and they are virtually all linked to digestive problems. The two medications significantly lower the number of cases of constipation without noticeably increasing the number of cases of diarrhea. The comparison of the number of digestive symptoms which appeared under treatment only underline one significant difference between the 2 groups (p0.05): the appearance of 5 times less the number of abdominal pains with TX 1341 (2 cases). Cases of irregular intake are significantly higher with the reference drug than with TX 1341 (respectively 23.7% and 8.5%; p0.01).

Diffuse non auto-immune hyperthyroidism is a rare entity, classically restricted to cases with hypersecretion of TSH, hCG or related molecule and to a few reports of proven paraneoplastic origin. The authors try to individualize another type of diffuse hyperthyroidism, previously considered to belong to Graves' disease, but without any sign of disimmunity. They present a familial form with several hyperthyroidic patients who showed neither change in humoral immunity nor immunological abnormality within the thyroid gland, even in those that were operated upon without prior antithyroid medication. Similar findings occurred within several series of hyperthyroid glands separately studied by the authors, using different techniques: histomorphometric quantification of lymphocytic infiltration, immunofluorescence in the search of IgG, IgA, IgM, C1 q, C3 and C9 fractions, or T-lymphocyte subsets. These techniques generally tend to yield positive results, that agree with an auto-immune pathogenesis, but totally negative findings do occur. This type of diffuse hyperthyroidism should be delineated from the common auto-immune type, and might be called toxic hyperplasia.

Several morphological alterations of the basement membrane of the seminiferous tubules have been reported in the patients presenting with a testicular sterility. The proteoglycans are one of the major components of the basal membrane and may be ultrastructurally defined by the use of the cationic marker polyethyleneimine (PEI). In comparaison to the normal distribution of the anionic sites labelled by PEI which is characterized by a regular pattern of distribution along both the epithelial and the interstitial faces of the lamina densa, the pattern of distribution of the sites is largely altered in 6 patients, 27 to 40 years of age, with oligo- or azoospermia. Several types of alterations are reported: parallel thickening of the lamina densa with an abnormal distribution of the anionic sites inside the lamina densa, stratifications of the basal membrane depressing the seminiferous epithelium with anionic sites labelled on both faces of the lamina densa-like layers, massive expansions of the lamina densa with either a regularly circumferential labelling of the sites or a random type of distribution. The digestion of the sites by the enzyme heparitinase is highly suggestive of the presence of proteo-heparan-sulfate. The analysis of the distribution of the anionic sites may represent a usefull tool for studying the pathogenesis of testicular sterility.

From January, 1977, through December 1983, 62 patients with thyroid edematous ophthalmopathy were given external orbital radiotherapy according to S.S. Donaldson's technique: 5,5 MV photons produced by a linear accelerator were used to irradiate the muscular conus, with a total of 20 grays in 10 sessions over 2 weeks. Good results were obtained in 46 patients (77%). This simple therapy may be a first choice in recent ophthalmopathy.