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  • 1
    ISSN: 1432-0878
    Schlagwort(e): Endorphins ; ACTH ; MSH ; LPH ; Infundibular neurons ; Human hypothalamus ; Immunocytology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Chez l'homme, une population de neurones du noyau infundibulaire renferme des composés révélables par des I.S. dirigés contre les endorphines (α et β), l'ACTH, les MSH (α et β), et la β-LPH. Chez le foetus, ces neurones révélés par des I.S. anti-β-endorphine et anti-ACTH(17–39) sont identifiables dès la 11ème semaine. Ils renferment des grains de sécrétion immunoréactifs à l'anti-β-endorphine visibles en microscopie électronique. Chez l'adulte, de tels neurones sont situés dans le noyau infundibulaire. Leurs fibres se terminent autour des vaisseaux dans la zone de Green et la tige infundibulaire, ou au contact de péricaryons non immunoréactifs dans le noyau infundibulaire. Ces neurones sont indifféremment révélés par des I.S. anti-ACTH(17–39) ou anti-β-endorphine. Parmi cette population, les plus immunoréactifs sont marqués par des I.S. anti-α-MSH ou anti-β-MSH, anti-β-LPH, anti-α-endorphine ou anti-ACTH (1–24). Ces résultats suggèrent que des substances identiques ou apparentées aux endorphines, à la LPH, à l'ACTH et aux MSH sont élaborées par ces neurones probablement à partir d'une molécule mère similaire à la pro-opiocortine. Les fibres immunoréactives se terminant au contact des capillaires de l'éminence médiane pourraient intervenir dans le contrôle neuro-humoral de l'adénohypophyse, ou dans la modulation d'autres terminaisons peptidergiques ou aminergiques. Les fibres au contact de péricaryons non immunoréactifs peuvent correspondre à des relations avec d'autres neurones infundibulaires, peut-être dopaminergiques. This work was supported by grants from the D.G.R.S.T. (contract n∘ 78.7.2749, Director Prof. C. Bugnon)
    Notizen: Summary In man, discrete neurons of the infundibular (arcuate) nucleus contain compounds that can be stained with anti-endorphin (α and β), anti-ACTH, anti-MSH (α and β) and anti-β-LPH immune sera (I.S.) In the fetus, certain neurons stain with anti-β-endorphin or anti (17–39)ACTH starting from the 11th week of fetal life. At the ultrastructural level, these neurons contain elementary granules that are immunoreactive with anti-βendorphin. In the adult, neurons immunoreactive with anti-β-endorphin are found in the infundibular nucleus. Their axonal fibers terminate around blood vessels in the neurovascular zone and in the pituitary stalk, or establish contacts with nonimmunoreactive perikarya of the infundibular nucleus. These neurons can be stained with anti(17–39)ACTH and anti-β-endorphin I.S. The most reactive are also stained moderately with anti-α-MSH, anti-β-MSH, anti-β-LPH, anti-α-endorphin, or anti(1–24)ACTH I.S. These results indicate that, in man, compound(s) identical with or immunologically related to endorphins, β-LPH, ACTH and MSH are secreted by certain hypothalamic neurons. These agents probably originate from a common precursor molecule similar to the so-called pro-opiocortin. Immunoreactive fibers terminating around capillaries of the median eminence constitute a tubero-infundibular system that may be involved in the neurohumoral control of the adenohypophysis or in the regulation of other peptidergic or monoaminergic endings. Fibers also terminate close to nonimmunoreactive perikarya that might possibly be dopaminergic.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 1661-1679 
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reactivity of model compounds representative of the structures resulting from the first steps of curing in uncatalyzed (or LiClO4-catalyzed) N,N-diglycidylaniline/aromatic amine systems was studied. The results indicate that the intermolecular etherification either does not occur or is very slow under these conditions. Moreover, the latter situation is observed only in the very specific configuration when two hydroxyl groups are very close to each other. From these experiments, it can be inferred that the most likely reactions occurring after the epoxy-primary amine addition in uncatalyzed N,N-diglycidylaniline/aromatic amine systems are the are the epoxy-secondary-amine addition and the cyclization reactions discussed in a previous paper.
    Zusätzliches Material: 11 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 28 (1990), S. 3445-3466 
    ISSN: 0887-624X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Cured N,N,N′,N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDDM) based epoxy resins were investigated by high-resolution solid-state 13C-NMR spectroscopy. Associated hardeners were the most commonly used low reactivity 4,4--diaminodiphenylsulphone (DDS), as well as, for comparisons reasons, the higher reactivity 4,4′-diaminodiphenylmethane (DDM) with, in each case, a1 to 1 or 1 to 0.6 epoxy/NH ratio. In order to interpret the spectra, the poorly resolved aliphatic region was decomposed into elementary lines, the structural assignments of which were made using solution 13C-NMR data resulting from a previous model compound study. The main structural feature of all investigated systems is the predominance of small cyclic units resulting from intramolecular reactions of N,N-diglycidylaniline groups. The resins are therefore far less crosslinked that it could be anticipated from the functionality of the reactants. Using the low reactivity DDS still increases this effect, due to a higher proportion of residual non reacted secondary amines. Reducing the initial ratio of hardener could on the contrary lead to a higher proportion of reacted amine function, and thus to a higher crosslinking degree. A qualitative picture of such networks is given at the end.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 204 (1979), S. 1-15 
    ISSN: 1432-0878
    Schlagwort(e): Endorphins ; ACTH ; MSH ; LPH ; Peptidergic neurons ; Hypothalamus (rat) ; Immunocytology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Dans les cerveaux de rats ayant reçu une injection intra-ventriculaire de colchicine, une même population de neurones du noyau arqué et du noyau ventro-médian est indifféremment immunoréactive à divers I.S. dirigés contre les endorphines (α et β), l'ACTH(1-24), l'ACTH(17-39), les MSH (α et β) et la β-LPH, comme le démontrent des études comparatives sur coupes sériées. Ces neurones sont intensément marqués par l'anti-ACTH(17-39), l'anti-β-endorphine, l'anti-α-MSH et l'anti-β-MSH et plus faiblement immunoréactifs à l'anti-α-endorphine, l'anti-β-LPH et l'anti-ACTH(1-24). Exceptionnellement, certains neurones immunoréactifs avec l'anti-ACTH(17-39) et l'anti-β-endorphine sont faiblement ou non reconnus par l'anti-α-MSH et l'anti-β-MSH. Les fibres immunoréactives se terminent dans l'éminence médiane latérale et dans le noyau arqué lui-même, ou forment des voies ascendantes le long du III∘ Ventricule. Des études comparatives avec d'autres I.S. ou avec la technique de Falck et Hillarp, montrent que ces neurones sont différents de ceux producteurs de LH-RH, de somatostatine, de neurophysine, d'ocytocine, de vasopressine et de dopamine. Ces résultats suggèrent que certains neurones de l'hypothalamus du rat synthétisent plusieurs neuropeptides identiques aux ou immunologiquement très voisins des peptides du groupe endorphine, ACTH, α-MSH et β-LPH, vraisemblablement à partir d'un précurseur commun similaire à celui des cellules corticotropes adénohypophysaires. Ces neuropeptides ayant une origine cellulaire et moléculaire commune pourraient être impliqués comme neurotransmetteurs ou neuromodulateurs dans le fonctionnement du système nerveux central. This work was supported by grants from the D.G.R.S.T. (contract n∘ 78.7.2749) and from the I.N.S.E.R.M. (contract n∘ 81.79.113)
    Notizen: Summary In rat brains intraventricularly injected with colchicine, the same discrete neurons of the arcuate and ventromedial nuclei can be stained with antisera against α- and β-endorphins, (1-24)ACTH, (17-39)ACTH, α- and β-MSH, and β-LPH, as demonstrated by comparative studies in consecutive serial sections. These neurons are strongly reactive with anti-(17-39)ACTH, anti-β-endorphin, anti-α-MSH and anti-β-MSH, and more faintly stained with anti-α-endorphin, anti-β-LPH and anti-(1-24)ACTH. Exceptionally, neurons reactive with anti-(17-39)ACTH and anti-β-endorphin are poorly stained or completely negative with anti-α-MSH and anti-β-MSH. Immunoreactive fibers end in the lateral median eminence and in the arcuate nucleus proper, or form ascending pathways along the third ventricle. Comparative studies with other antisera or with the Falck and Hillarp technique show that these neurons differ from the elements producing LH-RH, somatostatin, neurophysin, oxytocin, vasopressin and dopamine. These results suggest that the same neurons of the rat hypothalamus synthesize several neuropeptides identical with or immunologically related to endorphins, ACTH, α-MSH and β-LPH, probably arising from a common precursor molecule similar to that found in the corticotropic cells of the pituitary. These neuropeptides of a common cellular and molecular origin might be involved in basic processes of the central nervous system as neurotransmitters or neuromodulators.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 38 (1989), S. 1065-1076 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Interesting crosslinked materials possessing good mechanical and thermal properties are obtained by condensation of 2,4,6-trimethylpyridine (collidine) with terephthalic aldehyde in the presence of an acidic catalyst. Fourier transform infrared spectroscopy has been used to follow the kinetics of the chemical reactions involved in the formation of the tridimensional network using aldehyde and ethylene absorption bands. The first steps of the reaction consist in the addition of aldehyde groups on the methyl groups of collidine followed by a dehydration reaction which leads to the formation of ethylenic functions. Crosslinking is obtained by an addition reaction of the methyl groups of collidine on the double bonds created in the first processes. These reactions are strongly dependent on the reaction temperature. Cured resins prepared with different acidic catalysts have been studied by carbon-13 NMR. p-Toluene sulfonic acid leads to residual aldehyde groups in the cured resins whereas no residual aldehyde groups are observed after a relatively short curing time when sulfuric acid is used as the catalyst. The networks created in the two cases are not equivalent and present different mechanical properties.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 16 (1972), S. 1585-1602 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: The chromatographic analysis of resol solutions in tetrahydrofuran solvent, by means of a set of columns packed with crosslinked polystyrene gels, has been carried out with adequate resolving power for a clear-cut qualitative or semiquantitative differentiation between various types of resols to be practicable. The resulting chromatograms, which show the distribution of different constituents by molecular size, could be interpreted by the use of reference substance and by calibrating the system with a number of compounds of known structures. The method has been used to investigate the way in which various reaction parameters (nature of catalysts, proportion of starting material, treatments undergone by the resols) affect the composition of resols. Different commercial products have been thus characterized. It has also afforded an insight into the progress of the polycondensation reaction as a function of time and helped to state the reactivity of different groups and unblocked ring positions. Thus, an hydroxymethyl group appears to be more reactive in the para than in the ortho position. Otherwise the reactivity of unblocked ring positions would be enhanced by an hydroxymethyl group in the ortho rather than para position.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Acta Polymerica 46 (1995), S. 241-246 
    ISSN: 0323-7648
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Chemical as well as structural modifications of highly branched polycyanurates can be achieved by using the reaction of dicyanates with monofunctional phenols. The key products of this reaction are iminocarbonic esters formed by addition of cyanato and phenolic groups. Two mechanisms are discussed for the second reaction step: an addition of two cyanato groups and an iminocarbonic ester (Route A) and a stepwise addition of iminocarbonic esters (Route B). The crucial difference between the two reactions is the number of abstracted phenolic groups per formation of one triazine ring: one for Route A and three for Route B. The effects of these reaction mechanisms on the gelation behavior and network buildup are studied theoretically with the help of cascade theory as well as experimentally by the reaction of dicyanate of bisphenol A with five different monophenols. The results clearly show that only with a model which is based on Route B can both the critical conversions at the gelation threshold and the gel fractions be modeled quantitatively. Furthermore, phenols with low pKa values were found to have an increased tendency of incorporation into the network.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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