I. D. Mitchell

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Three purine nucleoside analogues, penciclovir (PCV), acyclovir (ACV) and ganciclovir (GCV), were assessed for in-vivo genotoxicity in the mouse bone marrow micronucleus assay, together with the xanthine (purine) analogue, caffeine (CAF). All these compounds exhibit anti-viral properties and the first three are marketed anti-viral drugs. All have been shown(More)
The importance of polyploidy as a genotoxic lesion is uncertain and there have been few publications and no reviews which have included data on spontaneous or induced polyploidy in routine genotoxicity screening. We have attempted to clarify some of the issues by reviewing the published literature and by reference to our historical data base for metaphase(More)
Data from a series of mouse micronucleus assays have been reanalysed to illustrate various statistical issues raised by Ashby and co-workers during the development of the assay. Most of the statistical points discussed in these earlier papers can be explained by the stochastic nature of the data. Reanalysis shows that the type of data collected in mammalian(More)
Data from micronucleus assays of 6 compounds were analysed by 3 non-parametric and 3 parametric methods. Two of the latter involved transformation of the data so several transformation strategies were investigated. It was concluded that the non-parametric Kolmogorov-Smirnov two-sample test was the most reliable method of analysis. None of the parametric(More)
The optimum concentrations of Aroclor-induced rat liver S9 microsomal fraction for the mutagenic activity of the four standard mutagens 2-aminofluorene (2-AF), acriflavine (ACR), benzo[a]pyrene (BP) and cyclophosphamide (CP) were determined in four mutation assays. The four assays were the Ames test using Salmonella typhimurium strain TA100, cycloheximide(More)
The definition of a negative result is a problem in genetic toxicology. Here we suggest that a result may be considered biologically unimportant (negative) if it falls within the limits of variation usually found in the negative controls of the particular test. To determine 'usual' variation, we have set 95% confidence limits on three indices of variation,(More)
The conditions under which noscapine causes high levels of polyploidy in vitro in human lymphocytes were investigated to try to determine its mode of action and to assess whether it was likely to be a genotoxic hazard when used as an antitussive agent. Irrespective of duration of treatment or type of medium, there seemed to be a threshold for polyploidy(More)