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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of molecular medicine 40 (1962), S. 264-266 
    ISSN: 1432-1440
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0738
    Keywords: 1,1-dichloroethylene (Vinylidene chloride) ; Metabolization rate ; Liver glutathione ; Hepatotoxicity ; Isolated perfused rat liver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Der Leberglutathiongehalt wird nach oraler Gabe von 1,1-Dichloräthylen (Vinylidenchlorid = VDC; in Olivenöl gelöst) gemessen und seine Bedeutung für Metabolismus und Hepatotoxizität von VDC untersucht. Nach oraler Applikation von 1000 mg/kg VDC sinkt Glutathion in 4 Std auf 33% der Kontrollwerte ab. Nach 24 Std sind die Kontrollwerte wieder erreicht. Der Abfall ist bei 18 Std-Nüchterntieren, die um 21% erniedrigte Ausgangswerte aufweisen, gleich. Die Glutathiondepletion ist dosisabhängig. Die Metabolisierungsrate von VDC in der isoliert perfundierten Leber beträgt nach 3 Std Perfusion, mit 5000 ppm VDC in der Gasphase, 7,64 μmol/g Leber. Die Rate ist um 18% erniedrigt, wenn der Glutathiongehalt mit Diäthylmaleat (25 μmol direkt ins Perfusat) auf 15% der Kontrollwerte gesenkt wird. Unter diesen Perfusionsbedingungen wird nach Diäthylmaleatzugabe die Funktionsfähigkeit (als Parameter hierfür dient der Lactat/Pyruvatquotient) der Leber eingeschränkt. Die Funktionsfähigkeit der Leber und die Metabolisierungsrate von VDC wird durch 18stündiges Fasten der Tiere nicht beeinflußt. Die Konzentration von Serumglutamatoxalacetattransaminase (SGOT) und Serumglutamatpyruvattransaminase (SGPT) im Perfusat ist nicht erhöht. Diese Befunde deuten darauf hin, daß keine Beziehung zwischen dem Leberglutathiongehalt und der erhöhten Letalität von VDC mit Nüchterntieren besteht.
    Notes: Abstract The liver glutathione content was measured after oral administration of 1,1-dichloroethylene (vinylidene chloride = VDC; dissolved in olive oil) and its significance for the metabolism and hepatotoxicity of VDC was investigated. After treatment with 1000 mg/kg VDC p.o., glutathione decreased to 33% of the control values within 4 h but returned to the control level after 24 h. An identical fall in glutathione after VDC administration was found to occur in animals which had been fasted for 18 h. In these animals the baseline values of glutathione were lowered by 21%. The depletion of glutathione was dependent on the dosage of VDC. The conversion rate of VDC by the isolated perfused livers was 7.64 μmoles/g liver after 3 h-perfusion, if 5000 ppm of VDC were supplied in the gas phase. Lowering the glutathione content to 15% of the normal value (by diethylmaleate, 25 μmoles added directly to the perfusate) resulted in a reduction of VDC conversion by 18%. Furthermore the viability (with the lactate/pyruvate ratio serving as the parameter) of the liver was distinctly depressed. No effect on viability nor on metabolization rate was noted when perfusing the livers of 18-h fasted animals. The concentrations of the glutamate-oxaloacetate transaminase (SGOT) and glutamate-pyruvate transaminase (SGPT) in the perfusate failed to show an increase. These findings indicate that there is no correlation between the liver glutathione level and the increased lethality of VDC in fasted rats.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 51 (1982), S. 183-186 
    ISSN: 1432-0738
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Conclusions Based on today's extensive experience on acute toxicity testing of chemical substances, and on the outcome of specific studies (Schütz and Fuchs 1982; Müller and Kley 1982; Lorke in preparation; Günzel et al. in preparation), it is now possible to conduct acute toxicity studies with the sacrifice of fewer animals and even to increase at the same time, the quality of the data obtained. Whereas for drugs, data on acute toxicity usually represents only part of the information available, for other chemical substances, acute toxicity may be the only data available, thus asking for more extensive examination of the animals used 'for this kind of study.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0738
    Keywords: Key words Trichloroethene ; Renal cell cancer ; Occupational exposure ; Epidemiological study
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  A retrospective cohort study was carried out in a cardboard factory in Germany to investigate the association between exposure to trichloroethene (TRI) and renal cell cancer. The study group consisted of 169 men who had been exposed to TRI for at least 1 year between 1956 and 1975. The average observation period was 34 years. By the closing day of the study (December 31, 1992) 50 members of the cohort had died, 16 from malignant neoplasms. In 2 out of these 16 cases, kidney cancer was the cause of death, which leads to a standard mortality ratio of 3.28 compared with the local population. Five workers had been diagnosed with kidney cancer: four with renal cell cancers and one with a urothelial cancer of the renal pelvis. The standardized incidence ratio compared with the data of the Danish cancer registry was 7.97 (95% Cl: 2.59 – 18.59). After the end of the observation period, two additional kidney tumors (one renal cell and one urothelial cancer) were diagnosed in the study group. The control group consisted of 190 unexposed workers in the same plant. By the closing day of the study 52 members of this cohort had died, 16 from malignant neoplasms, but none from kidney cancer. No case of kidney cancer was diagnosed in the control group. The direct comparison of the incidence on renal cell cancer shows a statistically significant increased risk in the cohort of exposed workers. Hence, in all types of analysis the incidence of kidney cancer is statistically elevated among workers exposed to TRI. Our data suggest that exposure to high concentrations of TRI over prolonged periods of time may cause renal tumors in humans. A causal relationship is supported by the identity of tumors produced in rats and a valid mechanistic explanation on the molecular level.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0738
    Keywords: Trenbolone ; Anabolic agent ; Cell transformation ; Syrian hamster embryo cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Trenbolone (TBOH), a synthetic androgen used as an anabolic agent in livestock, has been tested for mutagenicity in the Salmonella assay, for covalent DNA-binding in vitro, for induction of unscheduled DNA synthesis in HeLa cells and Syrian hamster embryo (SHE) fibroblasts and for morphological transformation of SHE cells. While TBOH gave negative results in the assays for mutagenicity and DNA damage, it was clearly capable of transforming SHE cells in culture. The natural androgen testosterone did not transform these cells. Thus, TBOH appears to be a substance which can transform cells independent of its hormonal action and without grossly damaging DNA.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 57 (1985), S. 214-215 
    ISSN: 1432-0738
    Keywords: Tartrazine ; Azo dyes ; Metabolic conversion ; Mutagenicity ; Salmonella typhimurium TA 98 ; FD & C Yellow No. 5 (5-oxo-1-(p-sulphophenyl)-4-(sul-phophenylazo)-2-pyrazoline-3-carboxylic acid, trisodium salt)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The azo dye tartrazine, after dosing by gavage, is transformed by rats into urinary metabolites which exert dose-dependent mutagenic activities in the Ames test with Salmonella typhimurium TA 98 after addition of rat liver metabolizing enzymes (S9 mix). The strain TA 100 showed no mutagenic response.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 59 (1986), S. 69-70 
    ISSN: 1432-0738
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 63 (1989), S. 250-251 
    ISSN: 1432-0738
    Keywords: Non-genotoxicity ; Acrylic acid ; n-Butyl acrylate ; SHE cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Acrylic acid (AA), ethyl acrylate (EA) and n-butyl acrylate (BA) are widely used in the production of plastics, coatings and acrylic fibres. Occupational exposure occurs primarily via inhalation and/or skin contact. In chronic inhalation experiments EA and BA did not induce neoplastic changes in rats and mice (Klimisch and Reininghaus 1984; Miller et al. 1985). Additional investigations showed that AA and BA were not carcinogenic in mice after chronic dermal application (De Pass et al. 1984). However, recently other authors reported a weak carcinogenic potential of AA and BA after chronic dermal administration to mice (Cote et al. 1986). The conditions of the latter study lead to the suggestion that the observed tumours had developed secondarily due to the local irritating and corrosive properties of AA and BA. This view is supported by the negative results of AA, EA and BA in the conventional Ames test (Waegemaekers and Bensink 1984). Mutagenicity data in mammalian cell systems of EA were equivocal (Henschler 1986) and were lacking for AA and BA. For this reason the mutagenic potential of AA and BA was investigated in Syrian hamster embryo fibroblasts (SHE cells). DNA repair (UDS assay), chromosomal changes (micronucleus assay) and morphological transformation were chosen as biological endpoints.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0738
    Keywords: 1,1-Dichloroethylene (Vinylidene chloride) ; Pharmacokinetics ; Biotransformation ; Mercapturic acid ; Molecular toxicity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The excretion and biotransformation of [14C] 1,1-dichloroethylene (vinylidene chloride, VDC) after administration of a single oral dose has been investigated in female rats. Seventy-two hours after a dose of 0.5, 5.0, and 50.0 mg/kg, 1.26, 9.70, 16.47%, respectively, are exhaled as unchanged VDC, and 13.64, 11.35, 6.13% as 14CO2. The main pathway of elimination is through renal excretion with 43.55, 53.88, 42.11% of the administered radioactivity. Through the biliary system, 15.74, 14.54, 7.65% of the activity are eliminated. The isolation of the main metabolites of VDC from 24 h urine is accomplished through the combined application of solvent extraction, ion exchange chromatography and thin layer chromatography. Then gas chromatography and mass spectrometry are used for their identification. Three metabolites have been identified: thiodiglycolic acid, N-acetyl-S-(2-carboxymethyl)cysteine and methylthio-acetylaminoethanol. In addition, three smaller unidentified radioactive peaks have been found. Thiodiglycolic acid is the main metabolite in VDC metabolism. The simultaneous formation of an ethanolamine- and a cysteine-conjugation product points to different reaction pathways of the postulated intermediate reactive epoxide; ethanolamine probably originates from membrane lipids, which react with VDC-epoxide and/or its derivatives. This pathway could explain, in part, the parenchyma damaging effect of VDC.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of toxicology 58 (1986), S. 207-213 
    ISSN: 1432-0738
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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