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  • 1975-1979  (4)
  • 1965-1969  (1)
  • Chemistry  (4)
  • Diastolic potential  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 293 (1976), S. 81-87 
    ISSN: 1432-1912
    Schlagwort(e): Supersensitivity ; Diastolic potential ; Perfused hearts ; Isolated right atria ; Norepinephrine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary It has previously been suggested that the reserpine-induced nonspecific increase in sensitivity of the guinea-pig heart to the chronotropic effect of drugs occurs as a result of an alteration in the electrophysiological properties of the cell membrane. The results obtained in the present study provide support for this suggestion. The diastolic potential of atrial cells of perfused hearts obtained from guinea pigs treated with reserpine (0.1 mg/kg/day) for 7 days was significantly less than control. This treatment schedule of reserpine results in a significant increase in the sensitivity of perfused hearts to the chronotropic effects of drugs. Treatment of animals with reserpine (0.1 mg/kg/day) for only 3 days does not increase the sensitivity of the perfused hearts and does not produce a significant change in the diastolic potential. Under appropriate experimental conditions, isolated spontaneously-beating right atria from chronically reserpine-treated guinea-pigs exhibit supersensitivity. Under the same conditions, there is a significant reduction in the membrane potential of atrial cells. Under conditions in which supersensitivity cannot be demonstrated in isolated right atria, there is no significant change in diastolic potential. These findings suggest that the reserpine-induced enhanced sensitivity of the myocardium to the rate-increasing effects of drugs may be a function of an altered membrane potential.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 1253-1259 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Studies have been made of the oxidation of styrene popcorn polymer that was grown on butadiene popcorn seed. It was found that the solubility of the polymer increased after oxidation. This solubility was studied as a function of both temperature and butadiene content of the polymer. Oxidation of the styrene-on-butadiene popcorn occurs at the carbon atoms alpha to a double bond in the butadiene portion of the polymer. This is followed by scission of the structure and the separation of linear atactic soluble polystyrene chains.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 23 (1979), S. 419-427 
    ISSN: 0021-8995
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Maschinenbau , Physik
    Notizen: Porous glass packing materials have been used for gel permeation chromatography using an aqueous phosphate buffer. Elution volumes were determined for polystyrene sulfonates, dextrans, and small neutral and charged molecules at three different ionic strengths, viz., 0.01M, 0.1M, and 1.0M phosphate, pH 7.0. The pore diameters of the glasses studied were 75, 240, 700, and 2000 Å. Elution volumes of nonionic species were unaffected by changing the solvent ionic strength. Elution volumes of charged species were markedly affected by the ionic strength of the solvent. This was attributed to a combination of decreased polymer dimensions and decreased ionic exclusion with increasing buffer concentration. The use of low ionic strength solvents may be exploited to tailor the separating range for polyelectrolytes with porous glass packings. This is particularly useful in the low molecular weight range where the lowest pore size available is 75 Å.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    ISSN: 0025-116X
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie , Physik
    Beschreibung / Inhaltsverzeichnis: Messungen der Linienbreite in den 1H NMR-Spektren von D2O Lösungen von Polymethacrylsäure (PMA) und von hydrolysiertem Butylvinyläther/Maleinsäureanhydrid Copolymer zeigen eine scharfe Abnahme der Linienbreite der Seitenkettenresonanzsignale bei einem Neutralisationsgrad α ≈ 0,2. Dies ist der Bereich, in dem schon früher potentiometrische Titrationen einen Konformationsübergang aufzeigten. Ein solcher Wechsel tritt weder bei der Polyacrylsäure noch beim Methylvinyläther/Maleinsäureanhydrid Copolymer auf. Die Art des Konformationsübergangs wird auf der Grundlage der Rotationsfreiheit der Seitenketten um die Hauptkette diskutiert.
    Notizen: Linewidth measurements on the 1H NMR spectra of D2O solutions of poly(methacrylic acid), (PMA), and the hydrolyzed form of butyl vinyl ether/maleic anhydride copolymer show a sharp decrease in the linewidths of side chain resonances at a degree of neutralization α ≈ 0,2. This is the region in which potentiometric titrations previously have shown a conformational transition to occur. Such a change does not occur in poly(acrylic acid) on the one hand and methyl vinyl ether/maleic anhydride copolymer on the other. The nature of the transition is discussed in terms of the freedom of rotation of the side chains about the main chain.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1978 (1978), S. 54-56 
    ISSN: 0075-4617
    Schlagwort(e): Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Mannich-Reaktion von 2,5-Xylenol, Morpholin und FormaldehydDie Reaktion von 2,5-Xylenol mit Morpholin und Formaldehyd in Isopropylalkohol ergibt in 65 proz. Ausbeute eine Mischung der p- und o-substituierten Mannich-Derivate 1 und 3 zusammen mit einer kleinen Menge der o,p-disubstituierten Mannich-Verbindung 2.
    Notizen: Reaction of 2,5-xylenol with morpholine and formaldehyde in 2-propanol affords in 65% yield a mixture of the p- and o-substituted Mannich derivatives 1 and 3 together with a minor amount of the o,p-disubstituted Mannich compound 2.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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