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  • 1
    Electronic Resource
    Electronic Resource
    Relationship between the melanin content of a human melanoma cell line and its radiosensitivity and uptake of pimonidazole (1993)
    Springer
    Cancer chemotherapy and pharmacology 31 (1993), S. 277-282 
    Details
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The intra-cellular uptake of the weakly basic radiosensitiser pimonidazole (PIMO) was determined as a function of the pigmentation of Na11+human melanotic melanoma cells in vitro. Two experimental conditions were considered: exponentially growing cells (Exp.) and plateau-phase cells (PI). The melanin content of Na11+cells ranged from 500 μg/g cell weight in exponentially growing cells to 6000 μg/g in heavily pigmented plateauphase cells. Cells were exposed to PIMO (medium dose, 0.2 mmol/dm3; 58.2 μg/ml). The intra-cellular concentration ranged from 163 μg/g in Exp. to 900 μg/g in pigmented Pl.; the latter being equivalent to an intra-to extracellular concentration ratio (Ci/Ce) of 17. However, this increase in the cellular uptake of PIMO was not accompanied by an increase in radiosensitising efficiency. In comparison, the Ci/Ce for etanidazole (ETA), a radiosensitiser that is uncharged at physiological pH, remained approximately constant at 1 for all values of melanin contents. Treatment of Na11+tumours in vivo with [3H]-PIMO resulted in a tumour: blood ratio of about 3 at 30–60 min after administration. However, at 24 h a grain count of label derived from [3H]-PIMO showed that picnotic areas of tumours contained levels that were some 40 times greater than the background value. This high level of label was coincident with areas of highest apparent melanin content. In conclusion, PIMO accumulates in very heavily pigmented melanoma cells present in necrotic zones with picnosis. As these cells are probably non-clonogenic, PIMO is not suitable for use in melanoma radiotherapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685671
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  • 2
    Electronic Resource
    Electronic Resource
    Metabolism of the anticancer agent 1-(4-acetylphenyl)-3,3-dimethyltriazene (1983)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 10 (1983), S. 485-488 
    Details
    ISSN: 0306-042X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: High pressure liquid chromatography was used in combination with mass spectrometry to confirm that the main products of in vitro metabolism of 1-(4-acetylphenyl)-3,3-dimethyltriazene are 1-(4-acetylphenyl-3-methyltriazene and 4-aminoacetophenone. In addition a novel metabolite, 1-[4-(1-hydroxyethyl)-phenyl]-3,3-dimethyltriazene, possessing antitumour activity similar to the parent drug, was identified.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bms.1200100808
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  • 3
    Electronic Resource
    Electronic Resource
    1H and 13C NMR spectra of the rotational isomers of N-hydroxymethylamides and derivativesPart V in the series ‘The Formation and Metabolism of N-Hydroxymethyl Compounds.’ For Part IV, see Ret. 7. (1985)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 23 (1985), S. 78-82 
    Details
    ISSN: 0749-1581
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A series of N-hydroxymethylamides, RCONR′CH2OH, and their O-methyl and O-acetyl derivatives, have been studied by 13C and 1H magnetic resonance spectroscopy. Signals have been assigned to the E- and Z-isomers on the basis of the analysis of the fully coupled spectra, and by comparison of the chemical shifts with those of model compounds. The introduction of the hydroxy, alkoxy or acetoxy groups at the α-position of the N-alkyl moiety causes a significant shift in the equilibrium towards the E-rotamer compared with the unsubstituted N-alkylamide. The predominant effect in determining the E: Z ratio appears to be the steric interaction between the carbonyl oxygen and the α-oxygen in the alkyl moiety; intramolecular hydrogen bonding does not play a significant role in determining the rotamer populations of these molecules.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260230205
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    Paper (German National Licenses)
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