Détection par immunofluorescence des cellules corticotropes et mélanotropes dans l'hypophyse de la grenouille,Rana temporaria L., au cours du développément

Summary During the embryonic and larval developmental stages of the frog, Rana temporaria L, anti- 1–24, 17–39 corticotropine, and MSH antibodies were used to define, with immunofluorescence technique, the appearence of corticotropic and melanotropic cells.A very small number of fluorescent corticotropic cells appears for the first time during the embryonic stage (10 mm), just before the differentiation of the pars intermedia. The cells are small, their large nucleus is surrounded by a fine rim of fluorescent cytoplasm.During premetamorphic stage, the anti-ACTH antibodies (anti- 1–24 and anti- 17–39 corticotropine) reveal more fluorescent cells in the whole pars distalis. The pars intermedia cells can also be visualized by both antisera.At the end of prometamorphosis and during climax the corticotropic cells show a more precise localization. As in adult frog pars distalis, they are concentrated in the rostral half of the lobe. With the same technique anti- and MSH antibodies reveal only the cells of the pars intermedia. No other cell type of the pars distalis reacts with these antibodies. This technique has the advantage to show that the ACTH and the MSH cells appear very early during the embryonic life.

     

Etude ecologique et floristique du plancton de cinq biotopes de la vallée de la Dyle

Sans résumé     

Analyse de la fécondation chez les Batraciens par l'hybridation et la polyspermie physiologique

Sans résumé     

Influence de la durée de l'éclairement sur la croissance du thalle de quelques algues (trois chaetophorales et une rhodophycee)

Thallus growth of some algae as a function of the light period (fluorescent white light about 1000 lux) shows that continuous light, or better 18 h of light, are the most effective; however short (1 or 2 h) and long dark periods inhibit growth. Except for Caespitella pascheri, monochromatic irradiations of 6 or 12 h (in addition to the 18 or 12 h of white light) inhibit the growth of algae. On the contrary, after 23 h of white light, monochromatic radiations stimulate growth and the more effective wavelengths are: 443, 475, 575 and 675 nm. With incandescent light (rich in near far-red and poor in blue light), the growth is low.     

Métabolisme de l'iode (131I) et formation de la scléroprotéine iodée (gorgonine) du squelette corné chez Eunicella verrucosa (Pallas)

The presence of gorgonins containing up to 10% iodine in the corneous skeleton of sea-fans (Gorgons) has long been known. The formation of iodinated amino acids in these proteins has been studied with radioactive iodine (¹³¹I).Gorgons (Eunicella verrucosa (Pallas), var. typica) immersed in sea-water containing tracer-doses of ¹³¹INa concentrate iodides with remarkable regularity. The efficiency of this process is such that in 15 days at 18°C nearly all the iodides present are fixed by the gorgons. Pottasium thiocyanate inhibits this phenomenon reversibly, as in thyroid gland.Radiochromatographic analysis of the proteins of living tissues and of corneous skeleton shows that both contain labelled 3-monoiodo- and 3 : 5-diiodotyrosine. Formation of iodothyronines has not been observed. The synthesis of the two iodinated amino acids seems to take place only in living tissue secreting the precursors of gorgonins. The fibres of these do not seem to be halogenated later.The presence of iodotyrosines in gorgonins is probably not bound to an elementary thyroid function, even if these compounds are accompanied by traces of thyroxine and 3 : 5 : 3′-triiodothyronine, as shown in previous researches. The role of iodotyrosines of gorgonins seems to be only structural; they are probably permanent constituents of the protein fibres of the corneous skeleton.     

L'effet de β-mercaptoéthanol et de l'urée sur la structure du phragmoplaste

Résumé Les fibrilles constitutives du phragmoplaste sont de nature protéique. L'action du-mercaptoéthanol permet de conclure que ces protéines sont liées par des ponts S-S. En présence d'urée, la structure du phragmoplaste est détruite, ce qui indique l'existence de liaisons hydrogènes.

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Zusammenfassung Unsere Arbeit führt zu folgenden Resultaten: 1. Die im Phragmoplast befindliche Faserstruktur besitzt einen Eiweißstoffcharakter. 2. Der Effekt des-Merkaptoäthanols gestattet die Annahme, daß die Proteine mit S-S-Brücken verbunden sind. 3. Bei Anwesenheit von Harnstoff wird die Phragmoplaststruktur zerstört, was für das Vorhandensein von H-Brücken spricht.

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Boursière de la Fondation Rockefeller     

Étude comparée de l'activité peroxydasique de l'hémoglobine,de la méthémoglobine et du complexe hémoglobine-haptoglobine

Kinetic studies of the peroxydase activity of hemoglobin and methemoglobin have been carrid out with oxygenated water as oxidising substrate and with gaïacol as electron donor. The values of kinetic constants have been determined and compared with those previously obtained for the hemoglobin-haptoglobin complex.Contrary to what might be presumed, the K_m and k_δ of the reaction catalysed by hemoglobin are not significantly different from those catalysed by the hemoglobin-haptoglobin complex. The character of the inhibition promoted by high concentrations of gaïacol is, however, different in the two cases. An attempt is made to explain this difference in terms of structural changes of hemoglobin resulting from the haptoglobin fixation.     

Nouvel outil pour la chirurgie du glaucome assistée par laser femtoseconde et tomographie de cohérence optique

We present a first evaluation of the results of the NOUGAT project which has been funded by the French National Research Agency through the 2008 edition of its TecSan program. The objective of the project is to conceive and realise an innovative device for ocular surgery by ultrafast pulse laser for glaucoma surgery assisted by an in situ imaging system. The main advances obtained during the project was the realisation of an ultrashort pulse laser source with a wavelength adapted to sclera transparency and the development of an optimised imaging system based on optical coherence tomography.     

Pratique de la circulation extracorporelle et médecine basée sur les preuves

The history of cardiopulmonary bypass (CPB) goes back to 1953, when Dr. Gibbon operated on a patient with atrial septal defect. Since, then a tremendous amount of knowledge has accumulated in this field. However evidence-based medicine (EBM) is scarce because practice of CPB relies mainly on current experience. The goal of EBM is to produce systematic reviews and clinical guidelines that summarise scientific knowledge about a topic in a single publication that preferably is updated regularly.EBM is more concerned by clinical outcome rather than by surrogate outcome. When available, meta-analyses are summarized on the role of surgical myocardial revascularization on CPB, intra-aortic balloon pump, priming and temperature of CPB, antibiotic prophylaxis, inhaled anaesthetics, haemostatic drugs, r-erythropoietin, fresh frozen plasma, blood washing and autologous transfusion, glucose-insulinpotassium infusion, fast-track, thoracic drain manipulations, respiratory physiotherapy and prevention of arrhythmias. However, many clinical issues persist (e.g., perfusion ouput and pressure, haemoglobin concentration, analyse of blood gases…) and new prospective randomised clinical studies should be encouraged.     

Etude des fluctuations annuelles des copépodes et du phytoplancton dans la manche et le golfe de gascogne par la méthode d'analyse de la variance et du coefficient de correlation

2275 samples have been collected with the Continuous Plankton Recorder of Hardy at a standard depth of 10 meteres in the English Channel and the Bay of Biscay between 1958–1965. Biological as well as statistical analyses have been carried out to provide data on annual fluctuations of 34 species of copepods and phytoplankton. Methods of analysis of variance and the correlation coefficient analysis were used for this purpose. The results are presented in the form of triangular matrices showing the annual fluctuations of species in the different areas considered and the relationship between different species in each area. These methods allowed us to define separate groups of species that could be called annual communities.

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Extrait d'une thèse de Doctorat en Oceanographie biologique, soutenue à la faculté des Sciences de Paris le 19 décembre 1967. Ce travail a été subventionné par the Office of Naval Research, Department of the United States Navy en vertu du contrat No 62558-3612.

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Extrait d'une thèse de Doctorat en Oceanographie biologique, soutenue à la faculté des Sciences de Paris le 19 décembre 1967. Ce travail a été subventionné par the Office of Naval Research, Department of the United States Navy en vertu du contrat No 62558-3612.