Evaluation of genotoxic effects of lead in pottery-glaze workers using micronucleus assay, alkaline comet assay and DNA diffusion assay.

PURPOSE: We investigated genotoxic effects of occupational exposure to lead acetate in pottery-glaze ceramic workers. METHODS: The study was carried out in 30 exposed workers and 30 matched controls, to whom several biochemical parameters-the blood lead (B-Pb; range: exposed, 41.68-404.77; controls, 12-52) and cadmium (B-Cd) level, the activity of delta-aminolevulinic acid dehydratase (ALAD), erythrocyte protoporphyrin (EP), the level of vitamin B(12) and folate in serum-were measured. The genotoxic effects were evaluated by the alkaline comet assay, the DNA diffusion assay and micronucleus test in peripheral blood lymphocytes. RESULTS: Subjects exposed to lead had significantly higher B-Pb level and, consequently, increased values of tail intensity (TI), frequency of apoptotic and necrotic cells, and frequency of micronuclei (MN). In contrast, their activity of ALAD, the level of vitamin B(12) and folate in serum were significantly lower compared to controls. Poisson regression analysis showed a significant correlation of profession, duration of exposure, smoking, level of cadmium in blood, ALAD and EP with primary DNA damage. A majority of primary damage repairs in a short period after exposure to a genotoxic agent. In addition, the influence of gender and level of vitamin B(12) and folate in serum MN frequency in exposed group was observed. CONCLUSIONS: In this study, DNA diffusion and micronucleus test showed higher influence of tested parameters to DNA damage. The results indicate a need for concomitant use of at least two different biomarkers of exposure when estimating a genetic risk of lead exposure.

DNA damage and repair after exposure to sevoflurane in vivo, evaluated in Swiss albino mice by the alkaline comet assay and micronucleus test.

The relationship between DNA damage and repair of peripheral blood leukocytes, liver, kidney and brain cells was investigated in Swiss albino mice (Mus musculus L.) after exposure to sevoflurane (2.4 vol% for 2 h daily, for 3 days). Genetic damage of mouse cells was investigated by the comet assay and micronucleus test. To perform the comet assay, mice were divided into a control group and 4 groups of exposed mice sacrificed on day 3 of the experiment, at 0, 2, 6 or 24 h after the last exposure to sevoflurane. Mean tail length (TL), tail moment (TM), and tail intensity (TI) values were significantly higher in exposed mice (all examined organs) than in the control group. Significant DNA damage immediately after exposure to sevoflurane was observed in leukocytes. Damage induction in the liver, kidney, and brain occurred 6 h later than in leukocytes, as expected according to the toxicokinetics of the drug, where blood is the first compartment to absorb sevoflurane. However, none of the tested tissues revealed signs of repair until 24 h after the exposure. To distinguish the unrepaired genome damage in vivo, the micronucleus test was applied. Number of micronuclei in reticulocytes showed a statistically significant increase, as compared with the control group at all observed times after the treatment.

Preliminary study of cytogenetic damage in personnel exposed to anesthetic gases.

Occupational exposure to anesthetic gases is associated with various adverse health effects. Genetic material has been shown to be a sensitive target of numerous harmful agents. The aim of this study was to examine whether chromosomal damage could serve to indicate exposure to anesthetics. A group of 43 hospital workers of three professions (anesthesiologists, technicians and operating room nurses) and 26 control subjects were examined for chromosome aberrations, sister chromatid exchanges and micronucleus frequency. The exposed groups matched in duration of exposure to anesthetics, but not in age. An equal ratio between women and men was possible in all groups except nurses. Likewise, the ratio between smokers and non-smokers was also not comparable. An increase in chromosome damage was found in all exposed groups. While the increase in sister chromatid exchange frequency was not significant, chromosome aberrations and micronucleus frequency increased significantly, showing higher rates in women. The results suggest that the micronucleus test is the most sensitive indicator of changes caused by anesthetic gases. The observed difference between sexes with respect to exposure risk call for further, targeted investigations.

Cytogenetic changes in subjects occupationally exposed to benzene.

Humans are exposed to benzene from various occupational and environmental sources. The genotoxic effects of benzene were assessed in peripheral blood lymphocytes of 36 workers employed in the shoe industry for a period extending from seven months to over 30 years. Chromosomal aberrations and sister chromatide exchanges were used as indicators of genotoxic effects. The incidence of dicentric chromosomes in the exposed group was significantly higher than in the control group (P < 0.05). No significant increase was detected between the working period in the exposed group and chromosomal aberrations. Sister chromatide exchange (SCE) frequency was not significantly increased in the exposed group.

Chromosome aberrations and micronucleus frequency in anaesthesiology personnel.

Occupational exposure to anaesthetic gases is associated with various adverse health effects. Genetic material is a sensitive target of numerous harmful agents. The aim of this study was to examine whether chromosomal damage could serve to indicate exposure to anaesthetics. Twenty-eight anaesthesiologists, 16 technicians, and 32 control subjects were examined for chromosome aberrations and micronucleus frequency. An increase in chromosome damage was found in both exposed groups. Micronucleus frequency increased significantly, showing higher rates in women. The observed differences between the sexes in respect to the exposure risk call for further, targeted investigation.

Analysis of sister chromatid exchange and micronuclei in peripheral blood lymphocytes of nurses handling cytostatic drugs.

The genotoxic effect of occupational exposure of 20 nurses who handled cytostatic drugs in medical oncology and haematology units was evaluated by micronucleus and sister chromatid exchange test. The duration of employment in the units and of exposure to cytostatics ranged from 1 to 31 years. The exposed nurses manifested an increase in cells with micronuclei as compared to the control group (P < 0.05). Nurses exposed to cytostatic drugs for 20-31 years showed a higher frequency of micronuclei (P < 0.05), whereas there was no difference in frequencies between the control group and the group exposed for 1-14 years (P > 0.05). The influence of the exposure period proved to be a significant parameter for the micronucleus test. No statistically significant differences were observed in sister chromatid exchange (P > 0.05).

Chromosome aberrations in operating room personnel.

BACKGROUND: Long-term occupational exposure to volatile anesthetic agents may result in various adverse health effects. Additionally, certain surgical procedures involve exposure to the other agents such as X rays. Identification of chromosome damages in peripheral blood lymphocytes serves as a useful indicator of exposure to mutagenic agents. METHODS: The frequency of chromosomal aberrations was assayed in peripheral lymphocytes obtained from 129 subjects working in operating theatres and 41 control subjects. RESULTS: The results show an increased rate of chromosome aberrations in the exposed subjects. The differences in frequency of chromosome aberrations between particular job tasks were not distinct. Acentric fragments in anesthesiologists and dicentrics in surgeons seem to stand out. CONCLUSIONS: As the findings do not differ significantly between the exposed groups, one can hardly distinguish radiation and anesthetics effects from one another.

Radiation-induced chromosomal aberrations and haematological alterations in hospital workers.

Long-term exposure to low doses of ionizing radiation may affect cells and tissues and result in various adverse health effects. The purpose of this study was to investigate whether chromosome aberrations and haematological alterations could be used as biomarkers of possible radiation injury in workers exposed to ionizing radiation. Groups totalling 323 medical professionals handling X-ray equipment and 160 control subjects were examined for incidence of chromosome aberrations and changes in leukocyte, lymphocyte and thrombocyte counts. The incidence of all types of chromosome aberrations was higher in the exposed groups than in controls, yet no significant difference was found between the exposed groups. A many-fold increase in chromosome aberration frequency in all exposed groups was not followed by a corresponding haematological depression. This suggests that chromosome aberrations are a significantly more sensitive indicator of changes caused by low doses of ionizing radiation than haematological alterations.

Chromosomal aberrations in medical staff occupationally exposed to X-rays: a follow-up study.

The decrease of unstable chromosomal damages (dicentrics, rings and acentric fragments) was observed in circulating peripheral blood lymphocytes after exposure to ionizing radiation. The study comprised 100 subjects, all medical staff occupationally exposed to X-rays, who were re-examined for unstable chromosomal aberrations after 3 months (12 subjects), 6 months (31 subjects), 9 months (13 subjects), 12 months (21 subjects), over 24 months (14 subjects), and over 36 months (9 subjects) controls were 60 subjects who were not exposed to ionizing radiation or chemical mutagens at their workplaces. The results did not show time-dependent recovery from chromosomal aberrations in all cases.

[Microbial degradation of xenobiotics in the environment]. / Mikrobna razgradnja ksenobiotika u okolisu.

Biodegradation of naturally occurring organic compounds follows their synthesis. In contrast, man-made compounds, also known as xenobiotics, are often refractory to degradation. The main reason is that they cannot be recognized by naturally present organisms and therefore do not enter common metabolic pathways. The physical and chemical characteristics of the compounds, as well as environmental factors, may influence their biodegradability. Some compounds may be transformed only in the presence of another compound which appears as a carbon and energy source. Very often compounds are degraded sequentially through the activity of a series of different organisms. The main degraders in nature are microorganisms, mostly bacteria and some fungi. These organisms, due to their rapid rates of multiplication and great metabolic potential, are able to adapt to new substrates. Selection of degradative potent microorganisms and their successive adaptation to a naturally persistent compound might be a powerful means for environmental detoxification. Although numerous laboratory experiments have given positive results, very few are applicable on a large scale. It is necessary to select microorganisms or microbial communities capable of controlled degradation of persistent organic chemicals without their transformation to other, more hazardous compounds. Better understanding of metabolic pathways for the biodegradation of specific organic compounds as well as more thorough knowledge of degrading microorganisms will make purposeful application of biodegradation possible.

[Levels of calmodulin and changes in cell physiology]. / Razina kalmodulina i promjene fizioloskog statusa stanice.

Calmodulin is a calcium-dependent regulator protein which activates about thirty enzymatic systems. Its intracellular levels, as well as the distribution between cytosolic and membrane fractions, are dependent on chemical (metal ions) and biological agents (hormones, viruses). The changes in levels are particularly pronounced after the cell transformation. The influence of transformation and the effect of chemical/biological agents are discussed separately as are the analytical methods for calmodulin determination. A detailed mechanism of action of chemical and biological agents on calmodulin levels is not yet known.