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  • 1
    Electronic Resource
    Electronic Resource
    Thioether concentration and mutagenicity of urine from cigarette smokers (1979)
    Springer
    International archives of occupational and environmental health 43 (1979), S. 159-166 
    Details
    ISSN: 1432-1246
    Keywords: Urinary thioethers ; Mercapturic acids ; Mutagenicity of urine ; Cigarette smoking ; Potentially alkylating agents ; Exposure test
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Urinary thioether compounds, such as mercapturic acids, can be considered as nontoxic end products of potentially alkylating agents. On the other hand, urinary mutagenicity may represent the excretion of potential mutagens that have not definitively been detoxified by the organism. It is suggested that a combined urinary thioether and mutagenicity test may be useful in monitoring people occupationally exposed to potentially alkylating compounds, in particular to mixtures of these chemicals. Exposure to cigarette smoke, containing several known mutagens and carcinogens, is expected to interfere with the test results. The excretion of mutagens and thioethers was determined in urine of smokers and nonsmokers. Smokers excrete more mutagens and thioether compounds than nonsmokers. Further, it was found that the urinary mutagenicity and thioether level are significantly related to the amount of cigarettes smoked.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381187
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  • 2
    Electronic Resource
    Electronic Resource
    Influence of ethanol induction on the metabolic activation of genotoxic agents by isolated rat hepatocytes (1985)
    Springer
    Archives of toxicology 57 (1985), S. 217-221 
    Details
    ISSN: 1432-0738
    Keywords: Benzidine ; 2-Aminofluorene ; 2-Acetylaminofluorene ; Dimethylnitrosamine ; Diethylnitrosamine ; Isoniazid ; Cyclophosphamide ; Ethanol-induction ; Cytochrome P-450 ; N-acetylation ; Isolated rat hepatocytes ; Mutagenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of ethanol-feeding to rats, over a 6-week period, on the activation of genotoxic compounds of different chemical classes, requiring metabolic conversion to exert their mutagenic activity, were studied in isolated rat hepatocytes. The influence of such treatment on cytochrome P-450 content and N-acetylation in isolated hepatocytes was also investigated. Benzidine (BZ), dimethylnitrosamine (DMN), diethylnitrosamine (DEN), isoniazid (INH) and cyclophosphamide (CP) were more effectively activated to products mutagenic towards Salmonella typhimurium by hepatocytes from ethanol-pretreated rats than by hepatocytes from controls. The mutagenic potency of 2-aminofluorene (2-AF) and 2-acetylaminofluorene (2-AAF) was not influenced by ethanol pretreatment. Ethanol consumption was found to be associated with increased cytochrome P-450 content and enhanced N-acetylation in the isolated hepatocytes. Our results support the hypothesis that an alteration of the hepatic drug-metabolizing system may be responsible for the ethanol-induced increase in susceptibility to certain genotoxic compounds.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00324780
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of toluene and xylenes on liver glutathione and their urinary excretion as mercapturic acids in the rat (1980)
    Springer
    Archives of toxicology 43 (1980), S. 293-304 
    Details
    ISSN: 1432-0738
    Keywords: Toluene and Xylenes metabolism ; Glutathione ; Mercapturic acids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Administration of toluene and xylenes to rats caused a decrease in liver glutathione concentration. The effect was most pronounced after the administration of o-xylene. 26% of the initial glutathione level was found three hours after treatment with o-xylene (4.0 mmoles/kg). No in vitro conjugation of o-xylene with glutathione was observed, neither spontaneously nor in the presence of 105,000 g supernatant from rat liver homogenate, containing glutathione S-transferases. Thus, a metabolite of o-xylene, which is not formed during incubation with 105,000 g supernatant, reacts with glutathione. A thioether was isolated from urine of rats given o-xylene; the compound was identified as o-methylbenzyl mercapturic acid by GC-MS and NMR. Chromatographic evidence was found for the presence of benzyl mercapturic acid in the urine of toluene-treated rats. The amounts of mercapturic acids excreted in the urine after administration of toluene, p-xylene, m-xylene, and o-xylene were 0.4–0.7, 0.6, 1.3, and 10–21% of the dose, respectively. These results demonstrate the involvement of a thusfar unknown pathway in the biotransformation of toluene and xylenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00366185
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    On the patterns of biomass transfer in the benthic fauna of an amazonian black-water river, as evidenced by 32P label experiment (1991)
    Springer
    Hydrobiologia 215 (1991), S. 153-162 
    Details
    ISSN: 1573-5117
    Keywords: Amazon Basin ; aquatic ecology ; leaf litter ; blackwaters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Leaf litter colonised by aquatic decomposition fungi was labelled with Na2H32PO4 and placed in a submerged litter bank in the Central Amazonian river Tarumã-Mirim. Of a total of 540 animals subsequently collected and analysed, 17% were definitely labelled. The phase-spatial pattern of label indicated that most species, notably fish and shrimps, were territorial with a radius of movement rarely exceeding 1 m; while chironomids and other microfauna are virtually stationary. From the distribution of labelled individuals within the litter bank and the gradual buildup of label it seems the fish feed within the same small area over periods of several weeks. The appearance of label in the shrimps was more erratic. The 32P appeared to be firmly retained within the living cells throughout the experiment and passed via the foodchains previously established by analysis of gut contents. The observed predator/prey density and foraging pattern have important implications for competition theory and the maintainance of species richness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00014718
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    Paper (German National Licenses)
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