De la réaction mitotique de l'épiderme de la tétine de cobaye à la suite d'applications répétées de diverses substances

Summary (1) The majority of substances tested produced a weaker mitotic reaction of the epidermis of the guinea pig nipple after 3 applications (24 h intervals) of the same substance than after a single application.(2) This decrease in the ability of the epidermic cells to be divided has to be attributed, it seems, to a habit-forming processus and not to an exhaustion of the cells; indeed after two applications of geraniol, the application of a substance of different nature, Hormoestrol, produced in the nipple epidermis a mitotic flare up as intense as that obtained in the epidermis of a nipple not previously treated.(3) Aldehyde C₉ alone, among the substances tested, does not produce a decrease of epidermic mitoses after three applications but induces cellular alterations.     

Importance des modifications de la glycémie dans la régulation de la vitesse d'absorption de solutions de glucose de différentes concentrations chez l'animal intact

Summary In intact guinea-pigs fed with glucose solutions of different concentrations, the main limiting factor of absorption is not the gastric emptying but the hyperglycaemia.     

Effet inhibiteur de la tétrabénazine sur l'influence corticosurrénalienne de la réserpine

Summary Reserpine provokes an intense and long-lasting (more than 20 h) stimulation of the adrenocortical activity of the rat. Tetrabenazin (50 mg/kg) also produces an adrenocortical stimulation which is, however, of a much shorter duration. The injection of tetrabenazin 1 h before the injection of reserpine (5 mg/kg) prevents the prolonged stimulating effect of reserpine on the adrenal cortex. This effect can be compared with the blocking effect of tetrabenazin, a short-acting central depressant with monoamine-liberator properties, against the prolonged central sedative influence of reserpine.     

Pharmacodynamie de la circulation cérébrale

Sans résuméRelation présentée au XXI^e Congrès International des Sciences Physiologiques, Buenos Aires, 9–15 août 1959.     

Essais de solubilisation et de détoxification de la Tyrothricine

Summary As Tyrothricin —Dubos's discovery of the antibiotic agent extracted from cultures ofB. brevis — does not give true aqueous solutions and retains, in the colloïdal state of the usually employed solutions, toxic properties for polymorphonuclear blood cells, we have attempted to effect the solubilization and detoxification of this compound. Treatment with formalin in given proportions results in making it water-soluble. The action of the formalin-treated compound on blood cells suspended in Ringer's solution seems to show a loss of toxicity. Subcutaneous and intramuscular injections in mice do not give visible general toxic effects, and the experiments incite to further investigations in this direction.     

Etude photophysique de la ptérobiline

Summary The first results of a photophysical study on pterobilin (biliverdin IX , a Lepidopter blue bile pigment) are presented. From the absorption and fluorescence spectra, it is deduced that the low yield of fluorescence indicates a desactivation of the excited singlet state occurring mainly by a non-radiative process. Analyses of the chemical compounds formed after irradiation of pterobilin in methanol show that it is rearranged into a series of new blue pigments among which phorcabilin and sarpedobilin (the two neobiliverdins IX isolated from Lepidopters) have been identified.

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Remerciements. Nous remercions le ProfesseurJ. Bergerard pour son intérêt. Ces recherches ont été réalisées dans le cadre de l'ATP CNRS No. 4699-10.     

Propriétés phytobiologiques de la sérotonine

Summary The serotonin (5-hydroxytryptamin) which shows a slight influence upon the growth of plant tissues, acts upon water uptake by regulating cellular permeability (latter is activated in the case of K⁺).     

La nature de la substance minérale de l'os

Summary In answer to objections put forward byBrandenberger andSchintz against their theory concerning the chemical nature of bone salts, the authors afford supplementary evidence about the real crystalline and chemical entity of hydrated tricalcium phosphate. According to the conditions, the precipitate contains either dicalcium phosphate or lime and this affects the nature of the product obtained by calcination.The mineral bone substance is not a hydroxylapatite because it turns either to carbonato-apatite or oxyapatite according to carbon dioxide being kept or not in the crystal lattice. The X-ray patterns of those two apatites are undoubtedly different.

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Réponse à une note deE. Brandenberger etH. R. Schinz, Exper.4, 59 (1948).     

Activitéin vivo de dérivés de la thiourée contre le virus de l'influenza

Summary A large number of sulphur-containing compounds bearing the thiourea group -NH-CS-NH-, including substituted thiocarbanilides, 1-acyl-4-arylthiosemicar-bazides, 1-(arylaminothioformyl)-thiosemicarbazides, 4-aryl-1-(arylaminothioformyl)- thiosemicarbazides, and other related substances have been tested for potential antiviral activity. Several of these compounds have been found chemotherapeutically active against influenza virus.

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Communication présentée au Congrès international de Chimie pure et appliquée de Zürich (Juillet 1955).     

Substances régulatrices de la croissance végétale

Zusammenfassung Durch Einwirkung von Simazin wird bei Elodea die Photosynthese gehemmt, der Sauerstoffverbrauch durch Atmung erhöht und keine Zerstörung der Zellbestandteile beobachtet. In Gegenwart von Simazin bleiben die Deshydrasesysteme der Zelle aktiv.

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5^e communication (voir les travaux précédents deA. Gast etB. Exer).     

Végétativisation de l'œuf de l'oursin par la Phénazone

Summary Phenazone employed in various concentrations on the eggs of the sea urchin,Paracentrotus lividus, has a powerful vegetalizing effect on their development. The role of the interference between phenazone and synthetic process of specific proteins is considered.     

Hydrolyse enzymatique de la propionylcholine,de l'acétylthiocholine et de la butyrylthiocholine par le rectus de grenouille

Summary The enzymatic hydrolysis of propionylcholine (PrCh), acetylthiocholine (AcThCh), and butyrylthiocholine (BuThCh), by extracts of the muscle rectus abdominis, was determined. Inhibition of this hydrolysis by D.F.P. and 3318 CT [bis(pipéridinométhylcoumaranyl- 5)cétone diméthiodide] — utilized over a range of concentrations covering both specific and non-specific concentrations—showed that PrCh is hydrolyzed by an acetylcholinesterase (70%) and an Xcholinesterase (30%), AcThCh by the AcChE (70%), the XChE (15%) and a thioesterase (15%) and BuThCh by the XChE (70%) and a thioesterase (30%).     

Purification de la pénicillinase deBacillus cereus

Summary A method for purification of Penicillinase fromBacillus cereus is described whereby we obtain the enzyme in a very pure form and in excellent yields. Starting from a crude acetone precipitate, the purification is obtained by using successive separations with ammonium sulphate, in controlled conditions, and final ion exchange.     

Répression par l'oxygène de la biosynthèse de la thiosulfate-réductase deProteus vulgaris

Summary The extracts obtained from aerobic cultures ofProteus vulgaris are completely without thiosulfate reductase activity. This phenomenon can be explained by the repression of biosynthesis of the enzyme by oxygen.     

Recherches sur le mécanisme de la rétraction du caillot et de la métamorphose visqueuse des plaquettes

Summary The concept, that viscous metamorphosis of platelets and clot retraction is initiated by thrombin and a dialyzable factor was confirmed. Under certain circumstances glucose acts as dialyzable factor. Clot retraction seems to depend upon the catabolism of glucose.     

Action répressive de l'oxygène sur la biosynthèse de la fumarique-réductase d'Aerobacter aerogenes

Summary The cells obtained from anaerobic cultures ofA. aerogenes contain both a hydrogenase and a fumaric reductase, but lack one or several electron transporters necessary for the coupling of the two enzymes. It is possible to measure the fumaric reductase activity of the extracts in the presence of hydrogen, hydrogenase and benzyl viologen, using the Warburg manometric technique. In anaerobic cultures the reductase is an inducible enzyme. In aerobic cultures its formation is strongly repressed by atmospheric oxygen.     

Analyse immunoélectrophorétique de la gonadotropine choriale humaine

Summary The purity of human chorionic gonadotropin showing an activity of 12,000/mg, is confirmed by immuno-electrophoretic analysis. Characteristic antigenic properties of this hormone are revealed by this method.     

Effet de l'hypothermie modérée sur le comportement maternel de la rate

Summary The maternal behaviour in the female white rat was ascertained by the method of spontaneous reactions to several stimuli.The observed rats were divided into two groups, and each of them was refrigerated once a day, by the method of detension, from the fourth to the seventh day after parturition, the body temperature attained being, on an average, 30°C. Females of the first group were refrigerated in recipients of the capacity of 2 1, and females of the second group in recipients of the capacity of 5 1.Disturbances of maternal behaviour were much more pronounced in the females refrigerated in recipients of the greater capacity than of those refrigerated in smaller recipients.     

Nouvelle méthode de préparation de la préalbumine sérique et principales caractéristiques physico-chimiques

Summary Prealbumin is prepared by a new method. Its homogeneity is demonstrated and its electrophoretic behaviour is discussed. Some new physico-chemical characteristics are determined.