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  • 1
    ISSN: 1432-198X
    Keywords: Atopy ; IgA nephropathy ; Henoch-Schönlein purpura ; IgE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The incidences of clinical and biological markers of atopy were investigated in 16 children with IgA nephropathy (IgAN) (group A) and in 22 with Henoch-Schönlein purpura nephritis (HSPN) (group B). The incidence of increased plasma IgE levels according to age-matched normal values was significantly higher in group B (17/22, 77%) than in group A (7/16, 44%) (P〈0.05). Although not significant, the incidences of positive RAST tests and of a history of typical atopic symptoms were also higher in group B [10/22 (45%) and 11/22 (50%), respectively] than in group A [4/16 (25%) and 5/16 (31%), respectively]. Moreover, IgE deposits were demonstrated by a peroxidase/anti-peroxidase method on cutaneous Langerhans and mast cells in 4 of 6 patients with HSPN. Thus immunoallergy might account, in some cases, for the cutaneous, intestinal and pulmonary signs observed in HSPN, but not in IgAN. We postulate stimulation of IgE-sensitized mast cells by specific antigens in the presence of IgA circulating immune complexes (CIC), release of vasoactive substances, increased capillary permeability and perivascular deposition of IgA CIC.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 347 (1966), S. 191-198 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Dielectric measurements on trimethylvinyl, allyl, and butenyl silane have shown that the vinyl silane has a structure being similar with that of trimethylphenyl silane. Where as in the latter compound, however, six electrons are on a seven-centric molecular term, the two π-electrons of the vinyl compound are on a three-centric one. In both cases the Si atom exhibites +I inductive and -M mesomeric action. The reactivity of allyl silane is due the strong M and E effect resulting from CH2 hyperconjugation and the +I effect of Si.
    Notes: Dielektrische Untersuchungen an Trimethyl-vinyl, Allyl- und Butenyl-silan zeigten, daß Vinyl-trimethyl-silan eine ähnliche Struktur wie Phenyl-trimethyl-silan besitzt mit dem Unterschied, daß die zwei π-Elektronen bei der Vinylverbindung auf ein trizentrisches, hingegen bei der Phenylverbindung sechs Elektronen auf ein heptazentrisches Molekülniveau gelangen. In beiden Fällen übt das Silicium eine +induktive (+I) und -mesomere (-M) Wirkung aus. Die Reaktionsfähigkeit der Allylverbindung ist dem stark erhöhten M- und E-Effekt zuzuschreiben, der durch den Hyperkonjugationseffekt der CH2-Gruppe und den +I-Effekt des Siliciums hervorgerufen wird.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 367 (1969), S. 293-302 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: For a general investigation on the Si—N bond N-substituted (silyl)-pyrrole derivatives have been prepared by means of already known, and new, methods. The dipole moments of these compounds were determined and their UV spectra recorded. From these data it is concluded that the Si—N bond has partial double bond, dπ-pπ, character. The lone electron pair on the nitrogen is however, displaced towards the silicon only to a small extent, owing to the stronger electron attracting effect of the pyrrole ring. These conclusions are by quantumchemical estimations.
    Notes: Für Untersuchungen über die Si—N-Bindung wurden N-substituierte Pyrrolderivate teilweise nach bekannten, z. T. nach neuen Methoden hergestellt. Es wurden Dipolmomente dieser Verbindungen nach HEDESTRAND ermittelt sowie ihre UV-Spektren aufgenommen.Dabei ergab sich, daß die Si—N-Bindung den Charakter einer partiellen Doppelbindung besitzt. Das einsame Elektronenpaar am Stickstoff ist aber nur geringfügig in Richtung der d-Bahn des Siliciumatoms verschoben; es tritt nur eine schwache dπ-pπ-Bindung auf, woraus folgt, daß der Pyrrolring wesentlich stärker elektronenanziehend wirkt als das Siliciumatom. Diese Folgerungen werden durch quantenchemische Berechnungen gestützt.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 377 (1970), S. 328-338 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On ground of DK and IR investigations it can be ascertained that the alkyl-alcoxy-silane - alcohol mixtures shows complex forming mainly at 2:1 molar ratio composition. In the case of monofunctional silane-alcohol mixtures this could be proved only on ground of infrared spectra. From the shifting on the v OH vibration the strength of the hydrogen bridge bond was calculated to be 4.29 kcal/mole.The ability to form complexes with acceptor character increases in direction of the tetra-function, and the disposition to form complexes with donor character in direction of the mono-function.In the associates the silicium atom is in sp3d hybridisation state. On ground of the DK and IR investigations on the mixtures of alkyl-phenoxy-silane - phenol it can be ascertained, that the complex forming is strongest at 1:1 molar ratio composition.
    Notes: Aus den Ergebnissen von DK- und IR-Messungen wird auf eine Komplexbildung von Alkyl-alkoxy-silan und Alkohol im Molverhältnis 2:1 geschlossen. Bei monofunktionellen Gemischen kann die Komplexbildung nur aus dem IR-Spektrum nachgewiesen werden. Aus der Verschiebung der v OH-Schwingung wird die Stärke der Wasserstoffbrückenbindung zu 4,29 kcal/mol errechnet. Die Neigung zur Bildung akzeptorartiger Komplexverbindungen steigt in Richtung der Monofunktion. Das Siliciumatom befindet sich in den Assoziationskomplexen im sp3d-hybridisiertem Zustande.Aus den Ergebnissen der DK- und IR-Messungen ist zu ersehen, daß die Komplexbildung im Alkyl-phenyoxy-silan und Phenol bei einem Molverhältnis 1:1 am stärksten ist.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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