Recherches sur la pseudo-cholinestérase du sérum et la cholinestérase vraie des globules rouges

Summary By means of a technic published in this journal (2, 66 [1946]), it has been observed that the activity of the pseudo-choline esterase of the serum is highest in presence of high concentrations of acetylcholine.The true choline esterase of the red corpuscules has her optimal activity at concentrations of 200 mg % acetylcholine. This high activity of these choline esterase is only going on during 3 to 5 minutes; after this period an inhibition occurs. At lower substrate concentrations (50 mg % acetylcholine) the difference in activity in the first and second phase is becoming less pronounced and the curve of the choline esterase activity becomes a straight line. At the small substrate concentration (4 mg % acetylcholine) again a primary higher choline esterase activity has been observed.Choline inhibitsin vitro the activity of the choline esterase. Prostigmine inhibits alsoin vivo andin vitro, the choline esterase of serum and globules.     

La phosphatase des os et le mécanisme général de l'ossification

Summary A general survey of the actual knowledges on the bone phosphatase is given. The enzyme plays an important rôle in the calcification of bone and teeth, this process being unable to proceed at a physiological speed without the participation of a phosphatase. The biological function of the enzyme is thus to accelerate and not to promote the calcification.The knowledge of the mechanism of phosphatase activity in the skeletal organs and of the chemical composition of the bone salt cannot lead to a full understanding of the physiology of ossification. A prominent function in this field is devoted to the proteins of the ground substance of bone and to their evolution. The study of the protein matrix of bone is now the most important subject of work for the biochemistry of ossification.

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Conférence faite le 28 mai 1946 au Hallerianum de l'Université de Berne.     

Sur le mécanisme de l'oligurie du Chien brûlé

Zusammenfassung Die an chloralisierten, fortlaufend infundierten Hunden eintretende Verminderung der Diurese nach Hautverbrennung ist weder auf eine Hypoproteinämie noch auf eine Erhöhung der Plasmaviskosität und auch nicht auf eine Reduzierung des Plasmavolumens zurückzuführen. Die mitgeteilten Versuche stützen vielmehr die Auffassung, daß durch Verbrennung ein antidiuretischer Stoff entsteht.     

Recherches sur la fraction Y des protéines de muscles de Lapin

Summary The proteinic material corresponding toDubuisson's electrophoretic gradient has been prepared by a new method. This fraction migrates as a single peak in the U-tube, but is heterogeneous in the ultra-centrifugation.     

L'action du chlorure de lithium et du sulfocyanure de sodium sur la viscosité de la nucléohistone et des extraits d'embryons d'Amphibiens

Summary (1) LiCl increases the viscosity and decreases the rigidity of nucleohistone; NaSCN has opposite effects.(2) The effects of LiCl and NaSCN on the viscosity of amphibian embryo extracts, as observed byRanzi and his coworkers, seem to be due to the action of these salts on nucleohistone.     

Action de l'orientation et de la qualité de la lumière sur le développement des protonémas de Bryales

Summary The radiations coming from Blanc Brillant de Luxe' fluorescent stimulate the growth and ramification of protonema ofCeratodon purpureus (Hedw.) Brid. This stimulation is caused by red light (660 nm). Multidirectional lightening is more favorable than unidirectional exposition.     

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.     

Effet du fluoroacétate et des rayons X sur la teneur en acide citrique du foie de la souris

Summary In contrast to rats, male mice injected with sodium fluoroacetate accumulate citrate in their livers, whereas females do not. Whole-body irradiation reduces the level of accumulated citrate in the liver as well as in other tissues of the mouse.     

Effets de l'irradiation sur le métabolisme des acides nucléiques et de leurs dérivés acidosolubles chez le rat

Summary In the rat, X-irradiation leads to a decrease of the net RNA and DNA content of the spleen, without, however, increasing the low molecular weight nucleic acid derivatives in the acid-soluble fractions of the same tissue. It is suggested that an alteration of the cell membranes could account for the apparent elimination of these nucleic acid degradation products which should normally appear in the acid-soluble fraction.     

Action des enzymes sur la gonadotropine urinaire de ménopause

Summary The action of various proteolytic and glucidolytic enzymes on the biological potency of Human Menopausal Gonadotropin was studied. Trypsin, chymotrypsin, papaïn and glucosidase attack the gonadotropin only after 6 h of digestion. Carboxypeptidase and RDE produce a rapid inactivation.     

Influence de laβ-mercaptoéthylamine sur la réponse de l'intestin grêle du rat à une irradiation rœntgénienne localisée

Summary Intra-peritoneal injections of 15 mg of B-mercaptoethylamine in rats, with an average weight of 200 g, protect the small intestine against a local irradiation of 500 r on the antero-upper portion of the abdomen.This protection is proved mainly, as compared with the control, by a smaller decrease of cells still in mitosis after 12 and 24 hours and of the migrant cells in resting stage, by a greater precocity and higher quantitative value of the post-radiation normal and subnormal mitotic processes, and by variations in the mitotic formula (namely, in protected animals, a relatively high increase in the amount of metaphases).These experiments seem to prove a certain local and immediate action of the radio-protector, whose effects are not solely limited to the preparation of the generating system of the intestine for the later complete repair of the digestive epithelium.

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(Travail du Centre anticancéreux de l'Université de Liège et du Centre national belge pour l'étude de la croissance normale et pathologique).     

Sur un mécanisme possible de la phosphorylation oxydative

Summary Two possible mechanisms for oxidative phosphorylation are suggested, based on participation of quinones in the process.Both of them postulate the 1–4 addition of inorganic phosphate on a reactive quinone isomer (the quinone-methide II) without exchange of the quinone oxygen atoms. They also account for the P₁-¹⁸OH₂ exchange observed during oxidative phosphorylation.

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Communication présentée au Symposium International de Chimie organique des Produits Naturels, Bruxelles (12–15 juin 1962). Résumé dans: Industrie Chimique Belge27, 558 (1962).     

Recherches récentes en Suisse dans le domaine des hormones

Sans résuméConférence tenue à l'occasion des «Journées biochimiques franco-suisses» à Bâle, le 26 mai 1946.     

Considérations cliniques sur le rôle des hémines

Sans résuméConférence principale, présentée à la Société suisse de biologie médicale lors de la 127^e Assemblée générale de la Société helvétique des sciences naturelles à Genève, le 31 août 1947.     

Influences des modifications simultanées de la concentration en ions K et Ca du liquide céphalorachidien sur le système vasomoteur

Summary In dogs anæsthetized with morphine-chloralosane, the cerebral ventricles are perfused with artificial solutions. After having been warmed up to body temperature, these solutions are allowed to flow into a lateral ventricle by a needle inserted laterally through the skull, the outflow taking place through a second needle placed suboccipitally in the cisterna. An excess of potassium in the cerebral ventricles increases the vasomotor tonus and the vasomotor responses produced by faradization of the central end of the vagus in the neck and by changing the pressure in the isolated carotid sinuses. An excess of calcium depresses the tonus of the vasomotor center and its reflex responses. An excess of calcium may be neutralized by an excess of potassium. Perfusion with a solution containing no calcium increases the tonus and the responses of the vasomotor center, while the absence of potassium does not seem to have any influence on the vasomotor system. A solution without potassium and calcium produces an increase of the tonus and the responses of the vasomotor center, these effects being due to the absence of calcium.