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  • 1
    Electronic Resource
    Electronic Resource
    Asymmetrically substituted calix[4]arenes; A two-dimensional ^1H NMR study of a tetraester derivative in the cone-conformation
    Amsterdam : Elsevier
    Tetrahedron 47 (1991), S. 1911-1924 
    Details
    ISSN: 0040-4020
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4020(01)96103-4
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  • 2
    Electronic Resource
    Electronic Resource
    Sensitive and selective determination of metabolically formed trans-dihydrodiols and phenols of benzo[a]pyrene in water and urine samples by HPLC with amperometric detection (1998)
    Springer
    Fresenius' journal of analytical chemistry 360 (1998), S. 95-99 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A method has been developed to separate hydroxylated metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene, i. e. trans-4,5-, 7,8-, 9,10-dihydrodiol and 1-, 3-, 7-, and 9-phenol, by HPLC with amperometric detection employing an isocratic methanol/water eluent (70:30, v/v) containing 0.5 g/L sulfuric acid and 1 g/L lithium perchlorate. Compared with the usually applied fluorescence (λex = 265 nm, λem = 460 nm) and ultraviolet (λ = 265 nm) detection, the amperometric technique is about 2–12 times more sensitive for the determination of all metabolites investigated. The method was applied to the determination of the seven metabolites of benzo[a]pyrene in different water samples and in urine after solid-phase extraction (SPE). The results obtained by HPLC with amperometric detection after SPE enrichment from an aqueous extract of a soil sample and from the urine of a rat intragastrically treated with benzo[a]pyrene agreed well with the values determined with fluorescence and/or UV detection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160050649
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  • 3
    Electronic Resource
    Electronic Resource
    Distribution and induction of aflatoxin B1-9a-hydroxylase activity in rat liver parenchymal and non-parenchymal cells (1996)
    Springer
    Archives of toxicology 70 (1996), S. 553-558 
    Details
    ISSN: 1432-0738
    Keywords: Key words Aflatoxin B1 ; Aflatoxin B1-9a-hydroxylase ; liver ; Nonparenchymal cells ; Parenchymal cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Chronic administration of aflatoxin B1 (AFB1) to rats gives rise to hepatocellular and cholangiocellular carcinomas without affecting Kupffer and endothelial cells. The enzymatic conversion of AFB1 to AFB1-8,9-epoxide is the critical step in the activation of the mycotoxin, while the conversion of AFB1 to aflatoxin M1 (AFM1), catalyzed by the AFB1-9a-hydroxylase, is considered to be a detoxication route for the toxin. In the present study the distribution and inducibility of AFB1-9a-hydroxylase were analyzed in microsomes derived from freshly isolated liver parenchymal (PC) and nonparenchymal cells (i.e. Kupffer+endothelial cells, NPC). AFB1-9a-hydroxylase activity was clearly measurable in NPC and similar to that of PC. In NPC the rate of formation of AFM1 was higher (when incubating with 16 μM AFB1) than or similar (with 128 μM AFB1) to that of AFB1-8,9-epoxide, while in PC it was significantly lower. Taken together, these results suggest that the AFB1-9a-hydroxylase activity might be particularly important in NPC to protect these cells from AFB1 by converting it to a significantly less mutagenic metabolite and by reducing the amount of AFB1 available for epoxidation. Furthermore, it is shown that AFB1-9a-hydroxylase activity is inducible by phenobarbital (only in PC), 3-methylcholanthrene, isosafrole and Aroclor 1254, thus indicating that in rat liver the conversion of AFB1 to AFM1 is catalyzed by members of the cytochrome 1A and 2B families.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002040050312
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  • 4
    Electronic Resource
    Electronic Resource
    Isolation, separation and quantification of metabolites of the carcinogenic polycyclic aromatic hydrocarbon dibenz(a,h)anthracene (1986)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 324 (1986), S. 357-357 
    Details
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00487992
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  • 5
    Electronic Resource
    Electronic Resource
    Conjugation reactions of polyaromatic quinones to mono- and bisglutathionyl adducts: Direct analysis by fast atom bombardment mass spectrometry (1988)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 15 (1988), S. 329-332 
    Details
    ISSN: 0887-6134
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The conjugation products of several reactive quinones with glutathione have been identified by fast atom bombardment mass spectrometry. Appropriate conditions have been developed which enabled the direct, dynamic mass spectral analysis of spontaneous, as well as glutathione transferase catalysed conjugation reactions. Applications to a series of quinones provided the direct detection and differentiation of the formation of mono- and bisglutathionyl adducts between regioisomeric quinone substrates in that only 1,4-quinones yielded bisglutathionyl adducts, which were not observed for the 1,2-isomers.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200150605
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  • 6
    Electronic Resource
    Electronic Resource
    Ionic membranes. II. Piezodialysis membranes from locally grafted polyethylene films (1977)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 15 (1977), S. 1541-1542 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1977.170150631
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  • 7
    Electronic Resource
    Electronic Resource
    Gelchromatographie. 2. Mitt. Des einfluß des verteilungskoeffizienten1. Mitt. vgl. Lit.-Zit.9. (1967)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 102 (1967), S. 63-72 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Gelchromatography is considered as a framework-limited partition. Equations derived from this conception are given. The dependence of the elution volume from the molecular weight was determined for oligophenylenes and oligourethans. These investigations were performed in the same solvent (tetrahydrofurane) und at the same temperature (25°C.) but with different gels:The gels used are: polystyrene crosslinked with divinylbenzene, poly(methyl methacrylate) crosslinked with ethylene glycol dimethacrylate, poly(vinyl acetate) crosslinked with butanediol divinyl ether.Relative differences in the elution volumes can be reduced to different interactions of the substances with the gel. This shows that beside the pore size distribution in the gel the partition coefficient has an important influence on the elution volume.
    Notes: Die Gelchromatographie wird als netzwerklimitierte Verteilung betrachtet; es werden die sich aus dieser Annahme ergebenden Gleichungen abgeleitet.Die Abhängigkeit des Elutionsvolumens vom Molekulargewicht wurde für Oligophenylene und Oligourethane geprüft. Die Untersuchungen wurden mit dem gleichen Lösungsmittel (Tetrahydrofuran) und bei der gleichen Temperatur (25°C), aber mit verschiedenen Gelen durchgeführt. Die verwendeten Gele sind: Polystyrol, vernetzt mit Divinylbenzol; Polymethylmetharcylat, vernetzt mit Äthylenglykol-dimethacrylat; Polyvinylacetat, vernetzt mit Butandiol-(1,4)-divinyläther; ferner ein mit Phenylisocyanat modifiziertes Dextrangel.Die mit den verschiedenen Gelen erhaltenen relativen Unterschiede im Elutionsvolumen lassen sich auf Unterschiede in der Wechselwirkung der angewandten Substanzen mit den Gelen zurückführen.Damit ist gezeigt, daß neben der Porengrößenverteilung eines Gels der Verteilungskoeffizient einen bedeutenden Einfluß auf das Elutionsvolumen hat.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1967.021020105
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  • 8
    Electronic Resource
    Electronic Resource
    Gelchromatographie. 8. Mitt.: Vernetzte copolymere des vinylacetats (1969)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 127 (1969), S. 113-140 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The properties of crosslinked copolymers of vinyl acetate were investigated in dependence of the mode of synthesis. Divinyl adipate and butanediol-(1.4)-divinylether were used as crosslinking agents.Homogeneously crosslinked gels may be prepared with excluded molecular weights up to 4000. A linear relationship exists between the specific gel bed volume and the excluded molecular weight.The heterogeneously crosslinking copolymerisation of vinyl acetate in presence of different inert diluents results in gels with excluded molecular weights 〉 106. The crosslinked copolymers were characterized by their apparent density, the uptake of solvents and non-solvents, the volume swelling, and the excluded molecular weight.
    Notes: Die Eigenschaften von vernetzten Copolymeren des Vinylacetats wurden in Abhängigkeit von den Herstellungsbedingungen geprüft. Als Vernetzungsmittel dienten Divinyladipat und Butandiol-(1.4)-divinyläther.Mit homogen-vernetzten Gelen können Ausschlußmolekulargewichte bis etwa 4000 erzielt werden: zwischen dem spezifischen Gelbettvolumen und dem Ausschlußmolekulargewicht besteht eine lineare Beziehung.Die heterogen-vernetzende Copolymerisation des Vinylacetats in Gegenwart verschiedener inerter Verdünnungsmittel führt zu Gelen mit Ausschlußmolekulargewichten über 106. Die vernetzten Copolymeren wurden durch ihre scheinbare Dichte, durch die Aufnahme von Lösungs- und Fällungsmitteln, durch die Volumquellung und durch die Bestimmung der Ausschlußmolekulargewichte charakterisiert.
    Additional Material: 27 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1969.021270107
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