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Marina González

Publications and source records attributed to Marina González.

6 recordsLinked to original sources
PubMed2003

Effect of dithiocarbamate pesticide zineb and its commercial formulation, azzurro. IV. DNA damage and repair kinetics assessed by single cell gel electrophoresis (SCGE) assay on Chinese hamster ovary (CHO) cells.

Single cell gel electrophoresis (SCGE) was used to analyse dithiocarbamate zineb- and the zineb-containing technical formulation azzurro-induced DNA damage and repair in CHO cells. Cells were treated with zineb (50.0 microg/ml) or azzurro (100.0 microg/ml) for 80min, washed and reincubated in pesticide-free medium for 0-12h until SCGE. Viability of treated cells (0 h) did not differ from control remaining unchanged up to 6h of incubation. After 12h, viability decreased up to 70 and 54% in zineb- and azzurro-treated cultures, respectively. SCGE revealed at 0 h the absence of undamaged cells and an increase of slightly damaged and damaged cells in zineb-treated cultures or by an increase in damaged cells in azzurro-treated cultures. For both chemicals, a time-dependent repair of pesticide-induced DNA damage within a 0-12h post-treatment incubation period was observed. Overall, damaged cells decreased as a function of the repair time for both pesticides while the slightly damaged cells decreased as a function of the repair time of zineb-induced DNA damage. Concomitantly, a time-dependent increase of undamaged cells was observed within the 0.5-12h repair time for both pesticides. At 12h after treatment, no differences in the frequencies of undamaged, slightly damaged and damaged cells were found between both zineb- or azzurro-treated cultures and control values as well as between zineb- and azzurro-treated cells. Immediately after exposure, nuclear DNA from zineb and azzurro-treated cells were larger and wider than nuclear DNA from untreated cells. When damaged cells were allowed to repair, a time-dependent decrease of the amount of free DNA migrating fragments was observed committed only to damaged cells but not in slightly or undamaged cells. On the other hand, no time-dependent alteration on nuclear DNA width within the 0-12h repair period was observed.

Animals↗
PubMed2002

Identification of novel mutations in the RB1 gene in Mexican patients with retinoblastoma.

Retinoblastoma (RB) is a childhood tumor of the eye with an average incidence of one case in every 15,000-20,000 live births and occurs in sporadic or hereditary form. This cancer results from loss or inactivation of the RB1 gene located at 13q14.1. This gene encodes for a 110 Kd nuclear phosphoprotein (pRB) that plays a major role in cell proliferation control. Different types of mutations in the RB1 gene have been reported, but point mutations are the most common. There are no molecular studies on RB1 gene mutation in Mexican patients. In this study, 19 patients with bilateral or unilateral RB were analyzed. Genetic and cytogenetic studies were carried out. Detection of RB1 gene mutations was done using single-strand conformational polymorphism (SSCP). Five conformational polymorphisms were identified in different exons. In all cases, SSCP sequence showed new non-described mutations that produced a frameshift on the open reading frame. The identification of mutations in the RB1 gene contributes to basic knowledge of this neoplasia and permits the possibility to offer adequate genetic counseling to relatives at risk.

Base Sequence↗
PubMed2002

Effect of dithiocarbamate pesticide zineb and its commercial formulation, azzurro. III. Genotoxic evaluation on Chinese hamster ovary (CHO) cells.

The in vitro genotoxicity exerted by the dithiocarbamate fungicide zineb, and its commercial formulation azzurro, were studied in Chinese hamster ovary (CHO) cells by the analysis of the sister chromatid exchange (SCE), cell-cycle progression and single cell gel electrophoresis (SCGE) assays. Both zineb and azzurro activities were tested within the range of 0.1-100.0 microg/ml. Concentrations of 0.1-25.0 microg/ml of zineb or azzurro induced a significant dose-dependent increase in SCE frequency over control values. For both test compounds, while doses ranging from 0.1 to 1.0 microg/ml did not alter the rate of cell proliferation, a significant delay in cell-cycle progression was observed within the 5.0-25.0 microg/ml dose-range. A regression test showed that either the proliferative replication index or the mitotic activity of cultures decreased as a function of the pesticide concentration within the 1.0-25.0 microg/ml dose-range. Doses higher than 50.0 microg/ml were cytotoxic. SCGE assay revealed an increase in zineb-induced DNA damage by enhancing the proportion of slightly damaged cells in the 25.0-100.0 microg/ml dose-range and by increasing in a dose-dependent manner the proportion of damaged cells within the 1.0-100.0 microg/ml dose-range. Overall, image analysis showed statistically significant positive relationships between zineb concentration and DNA damage (expressed by image length and width) and between length and width of the damaged cells. In azzurro-treated cells, only when 100.00 microg/ml was employed a significant increase in the frequency of damaged cells over control values affecting the totality of the cells was observed only when 100.0 microg/ml was employed. When lower doses were employed, no DNA damage was revealed. Based on these results, the evaluation of zineb as a genotoxic/non-genotoxic compound for human health should be reconsidered. Even though we demonstrate that the pesticide induces large DNA alterations in vitro, does no necessarily mean that the chemical should be considered clastogenic.notoxic

Animals↗