A mathematical model is described that predicts the effect of altered nuclear/cell division kinetics and cytotoxicity on micronucleus expression in vitro when the micronucleus assay is performed without discriminating between cells that have divided once and cells that have not divided after genotoxic insult. The model is based on the probabilities of: (i) a viable cell completing nuclear divis...

The Scientific Committee reviewed the current state-of-the-science on genotoxicity testing and provided a commentary and recommendations on genotoxicity testing strategies. A step-wise approach is recommended for the generation and evaluation of data on genotoxic potential, beginning with a basic battery of in vitro tests, comprising a bacterial reverse mutation assay and an in vitro micronucle...

The compounds 6-dimethylaminopurine and cycloheximide promote the successful production of cloned mammals and have been used in the development of embryos produced by somatic cell nuclear transfer. This study investigated the effects of 6-dimethylaminopurine and cycloheximide in vitro, using the thiazolyl blue tetrazolium bromide colorimetric assay to assess cytotoxicity, the trypan blue exclus...

background: in recent years, the widespread use of microwave producing instruments specially mobile phones; result in growing concern regarding the possible effects associated with these waves on human health. in the present study investigated the genotoxic effects of mobile phone radiation in adult mice (balb/c) and their embryos. methods: in this experimental research pregnant mice were irrad...

Inhabitants of the Hohhot Region in Inner Mongolia who drink highfluoride (4-15 mg/L) water were compared for their micronucleus (MN) rate and sister chromatid exchange (SCE) frequency in their peripheral blood lymphocytes. In persons with fluorosis as well as those considered "healthy", the MN rate and SCE frequency were significantly higher (t test) than in a neighbouring control group drinki...

A cytogenetic study was performed in lymphocytes of hospital workers occupationally exposed to X- and gamma-rays using the micronucleus centromere assay. A comparison of the data for the exposed group and an age-matched group of non-exposed hospital workers showed a significant (P < 0.05) increase in centromere-positive micronuclei for the radiation workers, while no effect on centromere-negati...

The micronucleus of Paramecium plays an essential role in the development of the oral apparatus in both asexual and sexual cycles. The present study analyses this somatic function of the micronucleus by interspecific transplantation of the micronucleus between two species, P. jenningsi and P. tetraurelia. The two species are similar in nucleogenesis in the sexual cycle, in the dependence of sto...

The development of the macronucleus from the zygotic micronucleus in the ciliated protozoan Tetrahymena spp. involves the elimination of specific DNA sequences (M. C. Yao and M. Gorovsky, Chromosoma 48:1-18 1974). The present study demonstrates that micronucleus-specific DNA is present on all five of the micronuclear chromosomes. Fragments of micronuclear DNA from Tetrahymena thermophila were c...

X-ray induced formation of micronuclei is generally thought to result from DNA double-strand breaks (DSBs). However, DNA DSBs inhibit the cell cycle progression that is required for micronucleus formation. In order to reconcile this apparent discrepancy, we investigated whether DNA DSBs induced during the G1 phase could lead to micronucleus formation. We irradiated human embryonic (HE17) cells ...