Demetrios P. Matthopoulos

Evaluating Side Effects of Human Exposure to Noxious Agents

Selenium is known to possess both genotoxic and antigenotoxic properties. In the present study, we have evaluated the genotoxicity and antigenotoxicity of three selenium compounds (sodium selenate, sodium selenite and selenous acid) by measuring in vitro micronucleus induction. Assays were conducted in whole blood lymphocytes and in the TK6 lymphoblastoid cell line, with and without co-treatment with potassium dichromate, a known genotoxic compound. In general, the compounds were more active in TK6 cells than they were in blood lymphocytes. Only 1 μM selenous acid increased the frequency of binucleated cells containing micronuclei (BNMN) in blood lymphocytes, while all three selenium compounds increased BNMN in TK6 cells. In addition, combinations of selenous acid and potassium dichromate resulted in lower frequencies of BNMN than potassium dichromate alone in blood lymphocytes, while combinations of sodium selenate and potassium dichromate produced lower frequencies of BNMN than potassium dichromate alone in TK6 cells.  The concentrations of selenium compounds that were used, in combination with the medium components and the biological physiology of the whole blood lymphocytes and TK6 cells, could have affected the redox potential of the compounds, switching the chemicals from a pro-oxidant to antioxidant status and vice-versa. The lower activities of the compounds in blood lymphocytes may be due to the protective effects of blood components. The results indicate that the genotoxic and antigenotoxic properties of selenium compounds are highly dependent upon the conditions under which they are evaluated.

Eduard Cemeli

Ricard Marcos

Diana Anderson

Genotoxic and antigenotoxic properties of selenium compounds in the in vitro micronucleus assay with human whole blood lymphocytes and tk6 lymphoblastoid cells

Nowadays, there is a constantly increasing concern regarding the mutagenic and carcinogenic potential of a variety of harmful environmental factors to which humans are exposed in their natural and anthropogenic environment. These factors exert their hazardous potential in humans' personal (diet, smoking, pharmaceuticals, cosmetics) and occupational environment that constitute part of the anthropogenic environment. It is well known that genetic damage due to these factors has dramatic implications for human health. Since most of the environmental genotoxic factors induce arrest or delay in cell cycle progression, the conventional analysis of chromosomes at metaphase may underestimate their genotoxic potential. Premature Chromosome Condensation (PCC) induced either by means of cell fusion or specific chemicals, enables the microscopic visualization of interphase chromosomes whose morphology depends on the cell cycle stage, as well as the analysis of structural and numerical aberrations at the G1 and G2 phases of the cell cycle. The PCC has been successfully used in problems involving cell cycle analysis, diagnosis and prognosis of human leukaemia, assessment of interphase chromosome malformations resulting from exposure to radiation or chemicals, as well as elucidation of the mechanisms underlying the conversion of DNA damage into chromosomal damage. In this report, particular emphasis is given to the advantages of the PCC methodology used as an alternative to conventional metaphase analysis in answering questions in the fields of radiobiology, biological dosimetry, toxicogenetics, clinical cytogenetics and experimental therapeutics.

Vasiliki I. Hatzi

Georgia I. Terzoudi

Christina Paraskevopoulou

Vasilios Makropoulos

Gabriel E. Pantelias

The use of premature chromosome condensation to study in interphase cells the influence of environmental factors on human genetic material

Pesticides are known to contain numerous genotoxic compounds; however, genotoxicity biomonitoring studies of workers occupationally exposed to pesticides have produced variable results. In this study, we employed the Comet assay to examine DNA damage in peripheral blood lymphocytes (PBLs) from 64 greenhouse workers from Almer&#xED;a in south-eastern Spain in comparison to PBLs from 50 men from the same area but not engaged in any agricultural work. The results indicated that there were no differences in the basal levels of DNA damage in the two study groups. In addition, exposure of PBL from the workers and controls to hydrogen peroxide or &#x3B3;-irradiation led to similar levels of DNA damage; the subsequent repair of the induced DNA damage was also similar for both study populations. Smoking had no impact on any of the responses. The results of this study indicate that the greenhouse workers had no detectable increase in DNA damage or alteration in the cellular response to DNA damage compared to our control population.

Stylianos M. Piperakis

Konstantina Kontogianni

Michael M. Piperakis

Ricardo Marcos

Smaragdi Tsilimigaki

Effects of Pesticides on Occupationally Exposed Humans

The alkaline single-cell gel electrophoresis (or Comet) assay was applied to evaluate the eventual DNA damage induced by the triphenolic metabolite of benzene, 1,2,4-benzenetriol (BT), in isolated human lymphocytes. Prior to BT treatment, ranging from 5 to 50 &#x3BC;M, a supplementation with glutathione (GSH, 350 &#x3BC;g/ml) was carried out to assess whether GSH may have a modulating effect on the Comet response. The effect of a fixed dose of BT was also evaluated in the presence of the exogenous antioxidant vitamin C (40 and 200 &#x3BC;M). Additionally, we investigated whether the polymorphism of glutathione S-transferase T1 (GSTT1) gene may affect the individual level of BT-induced DNA damage in vitro. For all donors included in the present study, BT produced a significant dose-response relationship. No clear effect of GSH preincubation was seen on the BT-induced response. On the contrary, a significant reduction of DNA damage was observed in the presence of vitamin C (at least at 200 &#x3BC;M). Although our data suggest some individual differences according to the GSTT1 genotype in the outcome of the Comet assay, a large number of individuals should be studied in further investigations to obtain reliable conclusions.

M. Pitarque

A. Creus

R. Marcos

Analysis of glutathione and vitamin C effects

Petroleum is one of the main energy sources worldwide. Its transport is performed by big tankers following some established marine routes. In the last 50 years a total amount of 37 oil tankers have given rise to great spills in different parts of the world, Prestige being the last one. After the accident, a big human mobilisation took place in order to clean beaches, rocks and fauna, trying to reduce the environmental consequences of this serious catastrophe. These people were exposed to the complex mixture of compounds contained in the oil. This study aimed at determine the level of environmental exposure to volatile organic compounds (VOC), and the possible damage induced on the population involved in the different cleaning tasks by applying the genotoxicity tests sister chromatid exchanges (SCE), micronucleus (MN) test, and comet assay. Four groups of individuals were included: volunteers (V), hired manual workers (MW), hired high-pressure cleaner workers (HPW) and controls. The higher VOC levels were associated with V environment, followed by MW and lastly by HPW, probably due to the use of high-pressure cleaners. Oil exposure during the cleaning tasks has caused an increase in the genotoxic damage in individuals, the comet assay being the most sensitive biomarker to detect it. Sex, age and tobacco consumption have shown to influence the level of genetic damage, while the effect of using protective devices was less noticeable than expected, perhaps because the kind used was not the most adequate.

Beatriz Pérez-Cadahía

Blanca Laffon

Eduardo Pásaro

Josefina Méndez

Genetic Damage Induced by Accidental Environmental Pollutants

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