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.     

Evolution et contrôle de l'activité de l'argininosuccinate synthétase,de l'argininosuccinase et de l'arginase du foie foetal de rat

Summary The activity of three urea-cycle enzymes, argininosuccinate synthetase, argininosuccinase and arginase have been studied in the ftal and new-born liver of rats. The activity increases with regularity between 17.5 days of pregnancy and birth in control foetuses. The lack of corticosteroid from 18.5 days of pregnancy decreases the activity of argininosuccinate synthetase. After administration of cortisol (hydrocortisone), to these 18.5-day-old foetuses lacking of corticosteroids, both activities of argininosuccinate synthetase and arginase are enhanced.

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Ce travail a été réalisé avec l'aide de la Délégation Générale à la Recherche Scientifique et Technique (contrat N^o 737 1148).     

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%).     

Cinétique de l'inhibition de l'oxydation cuprique de l'acide ascorbique par certains complexants

Summary The authors studied the kinetics of the inhibition of the copper-catalysed oxydation of ascorbic acid by versene and some proteins. The versene-inhibition attains slowly the theoretical value, when added after the Cu⁺⁺ to ascorbic acid. Proteins inhibit non-competitively and completely, when added to the vitamine either after or before the copper. This result may be interpreted as indicating an interaction between protein and the complex (AH-Cu⁺⁺).

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Note N^o 2 sur l'oxydation cuprique de l'acide ascorbique. Note N^o 1, voir réf.³.     

Quelques commentaires sur les méthodes de culturein vitro de jeunes blastodermes de poulet

Summary The relationship between yolk entoblast and the nutritional medium in cultures of chicken blastoderm, classical type, was studied. In addition, some refinements to the research ofNew ^5–7, and some modifications permitting operations from the dorsal side, are proposed.

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Travail subventionné par le Fonds national suisse de la Recherche scientifique.     

Action de la triéthylènemélamie sur les mitoses de segmentation de l'œuf de Pleurodèle

Summary Triethylenemelamine (1/400 to 1/12000) induces pseudo-chiasmas and chromosome-breakage in the egg-segmentation mitoses ofPleurodeles waltlii Michah. The primitive effect is stickiness, breakages appear subsequently, but without an interval of time between: the primary physiological and the secondary genetical effect cannot be separated. There are points of breakability, which explains the symmetry of certain fragments. The action is inverted in the epidermal cells of the larvae, where spindle alterations are prominent. Cytodieresis is never inhibited.     

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.     

Electrophorèse de protéines musculaires de Lapin

Summary Saline extracts from rabbit's skeletal muscles obtained and dialyzed at the ionic strength 0.15 contain at least 11 electrophoretically distinct components. Five of these components (n, m, t, l, s) have properties which are comparable with some characteristics of the myogens ofWeber, another component (h) is probably myoalbumin. Muscular proteins which are more soluble at higher ionic strength are not homogenous: there must be not one but two or more electrophoretically different myosins. Much work is needed to establish accurate relations between electrophoretic and classical muscular proteins.     

Etude immuno-électrophorétique de l'uromucoïde

Summary Concentrated normal urines were investigated by an immuno-electrophoretic technique using specific antiserum directed against uromucoid (=Tamm andHorsfall's urinary mucoprotein).A single precipitation line was observed, which, however, presented two distinct maxima. The faster antigen appeared to be situated between albumin and ₁-globulin, while the slower antigen seemed to be ana ₂-globulin. Both antigens were immunologically identical with uromucoid, although the latter had been eliminated by salt precipitation from the urines used in this experiment.The above findings can best be explained by assuming the occurrence of a polymer series of uromucoid, of which the lower members would be soluble in 0.58M NaCl, while the higher terms would representTamm andHorsfall's mucoproteinsensu stricto. It is suggested that cylindroids and nubecula represent visible forms of uromucoid.     

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).     

Observation et étude quantitative de corpuscules d'aspect virusal dans des cultures de sarcome de Rous

Zusammenfassung In vitro gezüchtete Zellen des Rous'schen Sarkoms wurden der Wirkung von Röntgenstrahlen und radioaktivem Alkohol (CH₃C¹⁴H₂OH) ausgesetzt und darauf elektronenoptisch untersucht. In einem geringen Prozentsatz der untersuchten Kulturen (9,5%) konnten virusartige Partikelchen von 60 bis 90 mµ Durchmesser intra- oder extrazellulär dargestellt werden, die mit den vonClaude, Porter undPickels gefundenen identisch sind und wahrscheinlich dem Rousschen Virus zugeordnet werden können. Es wurden Kolonien von solchen Gebilden intrazytoplasmatisch in Form von Einschlusskörperchen beobachtet. Auch unbestrahlte Kontrollen von Sarkomzellen wiesen Viruskörperchen auf, wenn auch bisher in geringerem Prozentsatz.Es ist vorderhand noch unsicher, ob der Bestrahlung eine primäre Rolle in der Darstellbarkeit dieser Viren zukommt.     

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.     

Groupements sulfhydriques de l'haptoglobine et de sa combinaison hémoglobinique

Summary Free and masked SH groups were determined in haptoglobine (Hp) haemoglobine (Hb) (horse) and in their complex (Hb-Hp). Hp contains no free SH groups, but up to 9 groups are liberated per mol on denaturation by guanidine. The Hb-Hp complex reacts with the same number of Hg⁺⁺ ions as free Hb, but it reacts with one less Ag⁺ ion than free Hb. The 4th Ag⁺ ion is taken up only in the presence of low concentration of a denaturing agent. Hg⁺⁺, Ag⁺, Cu⁺⁺ pcmb and iodine do not inhibit the association of Hb and Hp nor do they diminish the peroxidasic activity of the complex. Sh groups of Hb do not seem to be involved in these two reactions.     

Polarité électrique de fragments de Carotte cultivésin vitro

Summary The determination of PD's on carrot fragments growingin vitro has shown an electrical polarity of primary and secondary cultures of these tissues. The neoformations are negative in relation to the basis of the fragment. Controls, whether turned upside down or not, exhibit a similar polarity, which is influenced by the medium. The relation between electrical and morphological polarity cannot be stated at present.

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Grâce à un subside du Fonds national pour la Recherche scientifique, j'ai pu m'initier aux techniques récentes de culture de tissus dans le laboratoire deM. Gautheret, à Paris, que je remercie ici, ainsi que le Comité du Fonds (P.E.P.).     

Animalisation de l'œuf de l'oursinParacentrotus lividus par des substances polysulfoniques

Summary The effects of two compounds with sulfonic acid groups, chlorazol sky blue and Germanin (Bayer 205), are being studied on the developing egg of the sea urchin,Paracentrotus lividus. The chlorazol sky blue (1/5000) is a very effective animalizing agent. In dilute solutions (1/25000 and 1/100000), it induces the development of radial larvae. The lithium chloride counteracts the animalizing effects of chlorazol sky blue. The Germanin has an animalizing effect only at high concentrations. The penetration of these agents appears essential for the animalization. The reaction of the sulfonic acid groups with the basic groups of the intracellular proteins appears to be concerned with the animalizing effect. The results of these experiments are discussed in relation to the animalizing effects of various sulfonated dyes and zinc ions.     

Spécificité de l'action antiphage de substances synthétiques

Summary The effect of synthetic antiphages has been studied against different types of bacteriophage in the same bacterium, in this caseEscherichia coli. Most substances are active only against typesT ₁, 3, 5, 7 (and our type 207) but not against types 2, 4, 6. Others show activity only against type 1 (and our type 207). The antiphage activity of a substance therefore seems to depend upon a specific relationship between its chemical structure and that of the phage type against which it is active.     

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).