Showing papers by "Collège de France published in 1968"
TL;DR: The formation of 3H-5HT from3H-TRY was significantly increased in the brain of stressed animals and the utilization of this labelled amine synthesized endogenously was markedly accelerated during the stress situation.
200 citations
TL;DR: Some experiments are reported which show that CyAMP does, under proper conditions, antagonize the repression of enzyme synthesis by glucose.
170 citations
TL;DR: By their chemical composition and the enzymic activities which have been tested, non-nucleated cells appear to be similar to normal cells, except that they contain no detectable DNA and very little, if any, of the DNA-dependent RNA polymerase.
141 citations
TL;DR: In this paper, the authors compare the effectifs of the couche granulaire interne (cell. horizontales, bipolaires, amacrines et noyaux des fibres de Muller) with the retine dorsale and the ventrale du Pigeon.
Abstract: 1.
En comparant la retine dorsale et la retine ventrale du Pigeon, nous avons constate que la premiere etait considerablement plus riche en elements cellulaires de toutes sortes.
2.
Dans la totalite de la retine, la couche granulaire interne (cell. horizontales, bipolaires, amacrines et noyaux des fibres de Muller) possede un effectif de 3 a 5 fois plus nombreux que l'effectif des cellules receptrices.
3.
L'etude systematique de la repartition des effectifs de la couche granulaire interne dans l'ensemble de la retine fait apparaitre en position postero-dorsale l'existence d'une aire a forte densite cellulaire dont le centre est aussi riche que la fovea. La position et les dimensions de cette aire sont telles qu'elle peut etre assimilee au ≪champ rouge≫, territoire dans lequel les boules lipidiques rouges sont les plus nombreuses, ce qui donne a la retine en cet endroit une teinte orangee.
4.
Le champ rouge correspond donc a une area dorsalis aux possibilites fonctionnelles accrues. Cette aire recoit l'image du ≪champ du bec≫ et est utilisee lorsque l'animal regarde le sol, en vision binoculaire, en particulier lorsqu'il picore. L'area fovealis, compte tenu de sa situation ne peut servir qu'a la vision laterale, monoculaire.
140 citations
TL;DR: Changes in turnover of cerebral norepinephrine, as measured after intracisternal administration of the H3 amine, have been studied in rats during selective paradoxical sleep deprivation and its following rebound.
Abstract: Changes in turnover of cerebral norepinephrine, as measured after intracisternal administration of the H3 amine, have been studied in rats during selective paradoxical sleep deprivation and its following rebound. Experiments were performed under neurophysiological control. A marked increase of turnover of norepinephrine is associated with the augmentation of paradoxical sleep characteristic of the rebound period.
119 citations
TL;DR: This communication reports application of this method in Aspergillus nidulans to four loci where mutation can result in loss of ability to use sulphate but not sulphite as a sulphur source and indicates that theseFour loci are involved in the conversion of sulphate to a metabolite which interferes with utilization of exogenous choline O-sulphate.
Abstract: PHENOTYPIC analysis of interactions between different mutations in the same genome often helps elucidate the structure and function of the loci in question. If, in a series of mutations affecting a linear pathway, each non-allelic mutation has a characteristic phenotype, then the order of the steps they affect can be determined from the phenotypes of double mutants. A (“non-leaky”) mutation blocking one step in the pathway will be epistatic to all those blocking later steps. The minimum number of different double mutants sufficient to determine unequivocally the order of loci participation on a linear pathway equals the number of different loci (the total number of different double mutants equals n(n−l)/2 where n equals the number of different loci). This communication reports application of this method in Aspergillus nidulans to four loci where mutation can result in loss of ability to use sulphate but not sulphite as a sulphur source and indicates that these four loci are involved in the conversion of sulphate to a metabolite which interferes with utilization of exogenous choline O-sulphate.
95 citations
TL;DR: From the kinetic data of spectrophotometric titrations and loss of activity, it is concluded that one histidine residue and two histidine residues are modified per mole of arginine kinase and creatine kinase respectively, causing total inactivation.
90 citations
TL;DR: In this paper, the authors present results on annihilations of antiprotons at rest in hydrogen to the π+π−π0 final state, and they find that this channel is dominated by the ϱπ production.
79 citations
TL;DR: High voltage electrophoresis and thin-layer chromatography of the single fluorescent derivative isolated after pronase digestion of the dansylated enzymes led to the identification of e-DNS-lysine; these data provide evidence that the residue affected in both proteins is a lysine side chain.
72 citations
TL;DR: Results indicate that NA tuniover is not affected immediately after the operation, but is accelerated six days after adrenalectomy, and changes in central turnover of norepinephrine are studied.
59 citations
TL;DR: These experiments suggest that the process of binding l -arginine and some l -amino acids to the arginine kinase active site involves the interaction of the essential sulfhydryl group with the function of these compounds.
TL;DR: The cytology of the adenohypophysis of the male Japanese quail has been studied under a variety of experimental conditions: (1) treatment with long daily photoperiods for variable lengths of time; (2) the change from a long to a short daily photoprocessor which induces gonadal regression; (3) castration followed by exposure to either short or long day-long photopocessor as discussed by the authors.
Abstract: The cytology of the adenohypophysis of the male Japanese quail (Coturnix coturnix japonica) has been studied under a variety of experimental conditions: (1) treatment with long daily photoperiods for variable lengths of time; (2) the change from a long to a short daily photoperiod which induces gonadal regression; (3) castration followed by exposure to either short or long daily photoperiods, and (4) treatment with thyroxine, thiourea and metapirone. In parallel with the Cytological investigations, information on the level of hypophysial gonadotropins has been obtained by bioassay. The cytological investigations permit the recognition of seven types of cells in the adenohypophysis and the identification of gonadotropic cells, thyrotropic cells, and corticotropic cells. The significance of the orangeophilic alpha (STH ?) cells, and the erythrosinophilic eta (prolactin ?) cells remains hypothetical. A seventh cell type “kappa” is hypercyanophilic and positive with lead hematoxylin; it has been identified in other species of birds and may be a melanophorotropic cell. In castrates, an increase in pituitary gonadotropin appears only with photostimulation. It appears that photostimulation increases thyrotropic activity, an effect that is enhanced by castration.
TL;DR: Determination of serotonin and noradrenalin brain levels shows that ovulation is only affected by increased brain serotonin, and it is concluded that this amine has a specific inhibitory effect on the release of pituitary ovulation hormone.
TL;DR: In this article, X-ray analysis of β-lactams 5 and 6 confirms the cis configuration assigned before on the basis of their NMR spectra, and the valence bonds of nitrogen form a very flat pyramid and the dihedral angle between the Ar 2 phenyl and the β lactam ring, which is planar, is very small.
TL;DR: In this paper, total and differential cross sections for the reactions K−p → K+OΞ−O were measured between 1.26 and 1.84 GeV/c in a hydrogen bubble chamber.
TL;DR: Nos experiences d9excision des differents territoires encephaliques (Schowing, 1959, 1961, 1967) mettent en evidence l9importance du role des structures nerveuses dans the differentiation du squelette cranien.
Abstract: Nos experiences d9excision des differents territoires encephaliques (Schowing, 1959, 1961, 1967) mettent en evidence l9importance du role des structures nerveuses dans la differentiation du squelette cranien. Le mecanisme de cette action inductrice, ainsi que la nature de l9inducteur, est mal connu. Nous avons tente de confirmer le role inducteur de l9encephale par des experiences in vitro . Strudel (1959, 1962) a obtenu du cartilage a partir de somites d9embryons de poulet cultives sur le milieu standard de Wolff & Haffen (1952) contenant un extrait de tube nerveux, tandis que Benoit (1960), greffant un fragment de tube nerveux a la place de la placode otique, a observe l9apparition d9un cartilage surnumeraire dans le mesenchyme de l9oreille. Il semble done qu9il existe un facteur inducteur de la chondrogenese dans le tube nerveux. De meme, existe-t-il un facteur de l9osteogenese dans l9encephale embryonnaire? Ce facteur inducteur est-il specifique, comme son homologue chondrogene?
TL;DR: Ces resultats suggerent que les deux structures sont impliquees dans les mecanismes de retroaction par la testosterone, et qu'elles agissent sur la secretion et l'exeretion des hormones gonadotropes.
TL;DR: La destinee des gonocytes etant liee de facon irreductible a leur installation dans les ebauches genitales, ces cellules entreprennent, a chaque generation, une migration qui les conduit infailliblement aux epitheliums germinatifs.
Abstract: Chez les Vertebres, la segregation de la lignee germinate s9effectue des les stades les plus precoces du developpement. Les cellules germinales primordiales (CGP) apparaissent toujours hors des gonades et se trouvent souvent localisees dans des territoires bien delimites, plus ou moins eloignes des ebauches gonadiques presomptives. La destinee des gonocytes etant liee de facon irreductible a leur installation dans les ebauches genitales, ces cellules entreprennent, a chaque generation, une migration qui les conduit infailliblement aux epitheliums germinatifs. Les nombreux travaux consacres a ce sujet ont permis de distinguer deux modes de migration: — la migration interstitielle qui intervient lorsque les CGP sont situees posterieurement, a proximite des ebauches gonadiques; — la migration vasculaire qui entre en jeu des que les CGP se trouvent eloignees des epitheliums germinatifs. La migration interstitielle s9effectue par des deplacements actifs des CGP qui progressent grâce a leurs mouvements amœboides.
TL;DR: A simplified method of purification of sheep pituitary luteinizing hormone (LH) is proposed, using as starting material a fraction obtained in the course of purifying of follicle-stimulating hormone (FSH).
TL;DR: The structure and stereochemistry of tamaulipin-A (Ia), a new germacranolide isolated from Ambrosia confertiflora, was determined in part by conversion to a product also derived from saussurea lactone, a sesquiterpene lactone of known absolute structure as mentioned in this paper.
TL;DR: In this article, a study of the annihilations at rest was conducted and the authors found that the average rate (1.51 −0.13)×10−2 and the rate (2.8±0.9) × 10−3 from the analysis of events pp → 2π+2π−π0 and (3.3± 0.6) × 9−3.
TL;DR: L'arginine vasotocine est capable d'inhiber la réponse de la souris impubère à la stimulation gonadotrope, mais ne semble pas agir directement in vitro sur l'excrétion hypophysaire, comme le fait le facteur inhibiteur épiphysaire présent dans the poudre totale.
Abstract: L'arginine vasotocine est capable d'inhiber la reponse de la souris impubere a la stimulation gonadotrope, mais ne semble pas agir directement in vitro sur l'excretion hypophysaire, comme le fait le facteur inhibiteur epiphysaire present dans la poudre totale et dans la fraction F 3, obtenu apres filtration d'un extrait epiphysaire sur gel Sephadex G-25 (Fine).
TL;DR: In this paper, experimental results for the five-and six-body annihilations were presented for the D-meson, in terms of production of K∗(890), ϱ, ω, η and D(1280).
TL;DR: Although these results do not permit formal conclusions as to the importance of nonretinal photosensitive structures for gonado-stimulating mechanisms in the rat, they indicate that the problem deserves additional consideration.
TL;DR: The enzyme contains a flavin cofactor identified as FAD as mentioned in this paper, which can be used to detect reversible dissociation of the protein when analyzed in ultracentrifugation.
TL;DR: In this article, it was shown that an enzyme-protein complex can be formed; when horse radish peroxidase is incubated in the presence of both thyroglobulin and an H2O2 generating system, the reaction is linked to tyrosine molecules.
Abstract: In the preceding publication we have shown that horse radish peroxidase forms an enzymehalogen complex with iodide; first the halogen is oxidised by the enzyme forming the complex; secondly the oxidised halogen is transfered directly from the complex to acceptor proteins. Therefore we have assumed that an interaction may occur between the enzyme-halogen complex and the tyrosine residues of the protein acceptor.
In the present work we will show that an enzyme-protein complex can be formed; when horse radish peroxidase is incubated in the presence of both thyroglobulin and an H2O2 generating system, thyroglobulin isolated after the reaction is linked to peroxidase molecules. This complex is not formed when the H2O2 generating system is omitted. This result suggests that the tyrosine groups of thyroglobulin are oxidised by the peroxidase. Free tyrosine is indeed oxidised by the enzyme through a free-radical mechanism; the fact that 50% of the radioactivity, present in the 3,5 positions is freed as tritiated water indicates that [3,5-3H2]tyrosine forms a dimer during peroxidase oxidation. If free tyrosine is oxidised by such a mechanism we might assume that the residues of the same amino acid linked to a protein may be used as a substrate by the peroxidase. Such an assumption is supported by the fact that proteins are competitive inhibitors of the gaiacol peroxidative oxidation. If the tyrosine residues of the protein are oxidised as free radicals we might assume that the oxidised form of iodine linked to the enzyme is I. Therefore the mechanism of enzymatic iodination of proteins should proceed by an addition of free radicals.
We can conclude from kinetic studies that the presence of an increasing amount of protein, up to a certain limit, inhibits the iodination reaction. Iodide inhibits only when it is present in excess, where I2 is formed. From these results we might propose the following mechanism for the iodination reaction: the enzyme contains two sites almost identical; each of them should be able to form the complex with one of the two substrates, sequentially; when iodide is linked first, the velocity of the reaction attains maximum; when the protein is linked prior to the first site, iodide linkage to the second site is slowed and the velocity of the reaction reduced.
TL;DR: Four normal lactating glands of Mice and nine mammary cancers have been studied by quantitative electron microscopy and a relationship between the number of virus particles in the section area and the degree of organelle development does not exist.
Abstract: Four normal lactating glands of Mice and nine mammary cancers have been studied by quantitative electron microscopy.
TL;DR: La differenciation de l9epithelium bronchique s9effectue-t-elle seulement sous l9influence du mesenchyme pulmonaire est-elle suffisante pour permettre l9evolution normale de the bronche?
Abstract: On sait que l9organogenese pulmonaire (Dameron, 1961 a , b ) s9effectue seulement lorsque les deux constituants de l9ebauche, epithelium bronchique et mesenchyme pulmonaire, sont associes. Les interactions qui s9exercent entreles deux tissus sont indispensables pour la croissance et la differenciation de l9epithelium. Nous avons cherche a preciser la nature de ces interactions. Le mesenchyme maintient l9integrite de l9epithelium auquel il sert de tissu de soutien. Son role est-il simplement physique? ou bien son action est-elle veritablement inductrice et s9exerce-t-elle grâce a l9elaboration de substances morphogenes comme il en existe dans de nombreux types d9induction? Nous nous sommes egalement demandee quelle etait la specificite de ces interactions. La differenciation de l9epithelium bronchique s9effectue-t-elle seulement sous l9influence du mesenchyme pulmonaire? Ou bien la presence d9un tissu mesenchymateux quelconque est-elle suffisante pour permettre l9evolution normale de la bronche?