Etude du métabolisme d'une substance affectant la coagulation sanguine par la méthode des indicateurs radioactifs

Summary Radioactive 2-bromo-3-hydroxy-1:4-naphtoquinone has been used for the exploration of the metabolism of substances which influence the course of blood-clotting. It has been found that this substance diffuses very rapidly into the blood, and that the liver is not characterized by any elective fixation-power.     

Culturein vitro d'un tissu nymphal de lépidoptère

Summary Using a simplified medium, the composition of which is described in the text, cell cultures (fibroblast type) were obtained from nymphal ovarian tubes ofBombyx mori. The change in the form between fibroblasts and spindle cells is described. The preservation of activity of haemolymph congealed to – 20° C for a long time is shown; the advantages of using nymphs for cultivating tissues in virological series are also noted.     

Etude du remplacement catalytique du brome par l'hydrogène en présence du Ni-Raney

Summary We have just seen that the major course of a substitution reaction is determined by the nature of the groups already attached to the anthraquinone ring. The fact that pure members of the anthraquinone series may be readily prepared by catalytical dehalogenation, in the presence of Ni Raney under pressure at elevated temperature, is established. The fact that factors influencing the replacement of bromine by hydrogen are substituted groups in the para position is emphasized. These catalytic reductions are indicative of the peculiar effect of a substituted group on another atom or group in the para position.     

Effets de la réserpine sur le développement d'Oedipoda coerulescens L. (Acridien,Orthoptère)

Summary Inhibitory effects of reserpine on ecdysis and chromatic adaptation inOedipoda appear to be linked with changes observed in both neural and neuro-endocrine regulating systems.     

Avantages et inconvénients de la fixation par perfusion du tissu nerveux à la lumière d'une donnée de cytochimie

Summary It has been extensively demonstrated that perfusion is the best fixation procedure for providing good morphological evidence ofstructures, especially in the case of nervous tissue. But it might be questioned if it should also be preferred whencytochemical data have to be obtained or compared.As a preliminary attempt to answer this question, lipoproteic inclusions in nerve cells of vegetative ganglia of adult cat have been considered. These occur in about 25% of cells after immersion in fixative, whereas if perfusion is used, a relation appears between the amount of saline perfused before the fixative fluid and the percentage of cells containing inclusions: this falls to 10% after 300 ml saline, to 1% after 800 ml. In conclusion, though structural artefacts have been avoided and fixation appears excellent, perfusion is significantly responsible for a definite cytochemical alteration.     

Relations du « métabolisme respiratoire » des bactéries et du type de bactériophage avec l'activité de substances antiphages

Summary Quantitative determination of bacteriolysis with different T_1–7-phages confirms earlier observations that with substances inhibiting the action of T₁-phage the normal respiratory metabolism of the protected bacteria is quantitatively restored in every detail.With T₂-phage, showing a different respiratory course of bacteriolysis, no effect is obtained with the same substance, either on the respiration of the bacteria or on the typical course of respiration during bacteriolysis. The action of the phage inhibiting substance against T₁-phage is therefore an effect of definite specificity.     

Paléotempératures indiquées par l'analyse isotopique de fossiles du crétacé inférieur des Hautes-Alpes (France)

Summary Paleotemperature determinations were made by the oxygen isotope method on 20 Belemnoids, 5 Aptychi and a Nautilus beak from the Lower Cretaceous of the Dévoluy area of the Hautes-Alpes (France). The data derived show a well-defined trend from higher temperatures in the Berriasian to a climatic minimum in the Barremian followed by a rise to the Albian maximum, previously observed elsewhere in Europe. The Aptychi are shown to be useful paleotemperature indicators utilizable in conjunction with Belemnoids. A Sequanian Aptychus gave a high temperature reading, indicating that the climate steadily cooled from Upper Jurassic times into the Barremian. The single Nautilus beak gave a result suggesting that this group of fossils may also prove valuable in similar studies in the future. The paleotemperature data also showed (by the stratigraphic position of the relevant Belemnoids) that the Aptian is either very attenuated or absent in the Dévoluy.     

Déviation expérimentale de l'uretère primaire par la greffe de matériel cloacal chez le Triton

Summary A transplant consisting of the rudiment of a cloaca with some somatic material implanted at a certain distance ventral from the normal route taken by the pronephric duct can be the cause of a deviation of the duct from its normal course. The pronephric duct grows towards the secondary protodæum, whereas the duct is lacking in the part of the body behind the secondary proctodæum. It seems that the proctodæum exercises an attractive effect on the growing pronephric duct.The results of the experiments, at any rate, are in favour of the conception ofO'Connor (1938) andVan Geertruyden (1942), who found that the pronephric duct develops by its own independent growth. I cannot agree withVan Deth's opinion (1946), according to which the pronephric duct developsin situ out of the dorsal parts of the lateral plate.

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Expériences faites à Bruxelles, en avril 1947, grâce à une subvention de la « Nederlandse Commissie ter uitvoering van het Nederlands-Belgisch culturele verdrag ».     

Analyses immunoélectrophorétiques des fractions protéiques du sérum humain séparées par électrophorèse en gel d'amidon

Summary Human plasma components, separated by starch gel electrophoresis, are eluted and concentrated by lyophilisation. Immuno-electrophoretic analysis shows that certain of these fractions are immunologically heterogenous. The authors point out that this immunological criterium should be used before employing an eluted fraction, even if it appears electrophoretically homogenous.      

Virose aiguë à polyèdres déclenchée par action du fluorure de sodium

Zusammenfassung Borrelina-Virose wird in Larven vonBombyx mori nach Fütterung von 0,01% Natriumfluorid manifest. Das massenhafte Auftreten der Viren erfolgt trotz Ausschluss äusserer Infektion. Es wird eine Aktivierung von Elementen angenommen, die eine latente und spezielle Viruspotenz besitzen. Auf die enzymhemmende Wirkung des Natriumfluorids beim Gluzidabbau wird hingewiesen.     

Démonstration du caractère géographique de la parthénogénèse deSaga pedo Pallas et de sa polyploïdie,par comparaison avec les espèces bisexuéesS. ephippigera Fisch. etS. gracilipes Uvar

Summary The males of two species of Palestine,Saga ephippigera Fisch. andS. gracilipes Uvar have respectively 33 and 31 chromosomes in the diploid state.S. pedo Pallas, a parthenogenetic thelytoc species largely distributed in Europe, has 68 chromosomes and probably represents a tetraploid. The cells of the three species have identical dimensions and the polyploidS. pedo is even the smallest in size.     

Le degré de polymérisation de l'amylose,de l'amylopectine et du glycogène

Summary A colorimetric method based on the reducing power of the aldehydic end group has been developed in order to determine the M. W. of polysaccharides. It has been found that corn amylose contains chain molecules of much higher degree of polymerization than potato amylose.     

Etude des halos pléochroïques dans le granite de Medel (Massif du St-Gothard)

Zusammenfassung Es wird ein vorläufiger Maximalwert (60 Millionen Jahre) für das Alter der pleochroitischen Höfe des alpinmetamorphen Medelser-Granites (Gotthardmassiv) mitgeteilt. Das so bestimmte Alter dürfte demjenigen der alpinen Metamorphose entsprechen, welche die Biotite (mit ihren pleochroitischen Höfen) des wohl herzynischen Granites rekristallisieren liess.     

Analyse expérimentale de l'expression de la mutation léthale récessive («ulcère») chez l'embryon dePleurodeles waltlii (Amphibien Urodèle)

Summary The autonomous expression of a recessive lethal mutation (ulcèreu), isolated in the salamanderPleurodeles waltlii Michah. is demonstrated by the way of parabiotic and telobiotic associations, allogenic chimaeras, heterotopic grafts of organ primordia and of anterior or posterior parts from lethal embryos.     

Etude de la consommation d'oxygène et de la teneur en acide désoxyribonucléique du foie à divers âges chez le rat

Summary The quantitative study of whole liver DNA and liver nuclei DNA at various ages, and the simultaneous study of oxygen uptake shows the following facts:(1) The rate of oxygen consumption to the fresh weight or to the DNA or to diploid chromosomes group is the same for the adult or the young aged 8 days. The values of oxygen consumption calculated for one cell or for one nucleus (taking notice of the fact that the mean level of liver nuclei DNA varies with the age) at 8 days is only the half of the adult value. Even at two months the value is 20% lower than in the adult.(2) In older animals there is a decrease of oxygen uptake which is more noticeable on a cellular scale than with the classical rate to fresh or dry weight. We affirm the fact that the diminution of the oxygen uptake of each cell is compensated by the increase of the number of cells.     

Sur la caractérisation de dérivés guanidiques d'origine biologique par électrophorèse et chromatographie sur papier (chromatoélectrophorèse)

Summary Paper chromatography has been used in conjonction with electrophoresis in a perpendicular direction (chromatoelectrophoresis), in order to characterize various guanidoderivatives of biological interest and also citrulline. The isolation of definite spots can be obtained with a satisfactory selectivity by this procedure, at a higher speed than by bidimensional chromatography; and the use of a few coloured reactions (ninhydrine,Sakaguchi, diacetyle--naphtol andp-dimethylaminobenzaldehyde) on the same electrochromatogram has been successfully practised in this field.     

L'ultra-structure du nucléole de quelques cellules animales,révélée par le microscope électronique

Zusammenfassung Elektronenoptische Untersuchungen von Ultrafeinschnitten der Rattenleber sowie einiger anderer Gewebe dieses Tieres, ferner eines Mammakarzinoms der Maus und der Niere des Menschen haben ergeben, daß der Nukleolus des Zellkerns oft eine besondere Struktur aufweist: Auf genügend dünnen Schnitten (0,2µ>) erscheint sehr häufig ein Knäuel fadiger Elemente von verschiedener Länge, aber annähernd gleicher Dicke, die für die Gesamtheit des Nukleolus je nach seinem funktionellen Zustand zwischen 90–180 mµ variiert. Die Filamente sind Feulgen-negativ und enthalten demnach die Ribonukleoproteide des Kernkörperchens.