Semra Sardas

Mitochondrial DNA and Y-chromosome variation in the caucasus.

We have analyzed mtDNA HVI sequences and Y chromosome haplogroups based on 11 binary markers in 371 individuals, from 11 populations in the Caucasus and the neighbouring countries of Turkey and Iran. Y chromosome haplogroup diversity in the Caucasus was almost as high as in Central Asia and the Near East, and significantly higher than in Europe. More than 27% of the variance in Y‐haplogroups can be attributed to differences between populations, whereas mtDNA showed much lower heterogeneity between populations (less then 5%), suggesting a strong influence of patrilocal social structure. Several groups from the highland region of the Caucasus exhibited low diversity and high differentiation for either or both genetic systems, reflecting enhanced genetic drift in these small, isolated populations. Overall, the Caucasus groups showed greater similarity with West Asian than with European groups for both genetic systems, although this similarity was much more pronounced for the Y chromosome than for mtDNA, suggesting that male‐mediated migrations from West Asia have influenced the genetic structure of Caucasus populations.

Detection of oxidative DNA damage in lymphocytes of patients with Alzheimer's disease

Oxidative damage to DNA may play an important role in both normal ageing and in neurodegenerative diseases. The deleterious consequences of excessive oxidations and the pathophysiological role of reactive oxygen species have been intensively studied in Alzheimers disease. Although the role of oxidative stress in the aetiology of Alzheimers disease is still not clear, the detection of an increased damage status in the cells of patients could have important therapeutic implications. The levels of oxidative damage in peripheral lymphocytes of 24 Alzheimers disease patients and of 21 age-matched controls were determined by comet assay applied to freshly isolated blood samples with oxidative lesion-specific DNA repair endonucleases (endonuclease III for oxidized pyrimidines, formamidopyrimidine glycosylase for oxidized purines). It was demonstrated that Alzheimers disease is associated with elevated levels of oxidized pyrimidines and purines (p<0.0001) as compared with age-matched control subjects. It was also demonstrated that the comet assay is useful as a biomarker of oxidative DNA damage when used with oxidative lesion-specific enzymes.

Use of alkaline Comet assay (single cell gel electrophoresis technique) to detect DNA damages in lymphocytes of operating room personnel occupationally exposed to anaesthetic gases

Here, we report the possible in vivo induction DNA damage by exposure to various waste anaesthetic gases such as halothane, nitrous oxide and isoflurane. The alkaline comet assay (single cell gel electrophoresis technique) was carried out on 66 operating room personnel (anaesthetists [doctors]; anaesthesia nurses and anaesthesia unit technicians) currently employed at the Ankara Hospital in Turkey. A significant increase in the number of lymphocytes with DNA migration was observed in operating room personnel as compared to controls. Also, the extent of damage in exposed smokers were significantly higher than exposed nonsmokers. This study supports the existence of an association between DNA damage and occupational exposure to inhalation anaesthetics.

DNA damage evaluated by the alkaline comet assay in lymphocytes of humans anaesthetized with isoflurane.

In the present paper, we report data on the possible DNA damage, induced in vivo by isoflurane using the alkaline single cell gel electrophoresis technique (SCGE-comet assay) in patients before/after anaesthesia and in control group. Twelve patients, aged 22-66 years old, were anaesthetized for elective abdominal surgery with isoflurane in oxygen for 120-162 min (mean: 133.2 min). Venous blood samples were obtained from the patients before the induction of anaesthesia, at 60 and 120 min of anaesthesia and on the first, third and fifth following days of anaesthesia. SCGE was examined in 100 cells from each specimen graded as undamaged, intermediate and tailed nuclei. The number of undamaged nucleus was almost same in control and in patients before anaesthesia. However, significant differences were observed in proportion of undamaged, intermediate and tailed nucleus of patients at 60 and 120 min of anaesthesia and on the first day. DNA damage started to return to normal rates after the third day of anaesthesia and were almost identical with the rates of control group five days later.

Assessment of DNA damage in women using oral contraceptives

The effect of the use of an oral contraceptive (OC) on the frequency of sister chromatid exchanges (SCEs) and on the response in the alkaline comet assay (single-cell gel electrophoresis (SCGE)) was investigated in 18 women taking contraceptive pills daily for 24 months. As controls, fertile women were included with regular menstrual cycles who received no OC drugs. A significant increase in the number of lymphocytes with DNA migration and an increased frequency of SCE per metaphase were observed in OC users as compared with their age-matched untreated controls (P<0.005). As higher incidences of spontaneous SCEs in peripheral blood lymphocytes have been reported to occur in females during pregnancy due to profound changes in the levels of certain sex hormones such as progesterone and estrogen, particularly during the last trimester, 17 pregnant women served as positive controls in this study in order to test the rate of genetic damage due to those changes. Higher frequencies of SCEs and comet responses were observed in pregnant women than in their matched controls. However, no statistically significant difference in DNA damage was observed between OC users and pregnant women (P>0.05). This study underscores the fact that prolonged and extensive use of these drugs in our daily life may be hazardous and also, that OC users should be aware of multifactorial risk factors (environmental, genetic and life style patterns) that may be responsible for additional DNA damage.

Genotoxicity studies on professional hair colorists exposed to oxidation hair dyes

The cytogenic repercussions of occupational exposure to oxidation hair dyes were assessed by using three assays in professional hair colorists. The assays were sister chromatid exchanges (SCE) in circulating lymphocytes to evaluate the interchange of DNA replication products at apparently homologous chromosomal loci, single cell gel electrophoretic (SCGE) assay to detect the presence of DNA strand breaks/alkali-labile damage, and the Ames assay using Salmonella typhimurium strain TA98 to detect the urine mutagenicity. The ability of these assays to detect genetic damage caused by oxidation hair dyes in man compared with closely matched controls produced the following findings. (i) The SCE assay could not detect the mutagenic effect in lymphocytes of exposed subjects from whom complete data were obtained. However, subjects (controls and exposed) with a history of smoking had slightly increased SCEs than the non-smokers in both groups. (ii) The extent of DNA migration (SCGE assay) did not distinguish between the samples in either the exposed or control subjects. Like the SCE results, the exposed and control smoker subjects showed a greater proportion of damaged lymphocytes with apparent migration of DNA. (iii) No clear differences in the mutagenic activity of the urine samples were observed between the exposed and control subjects. But, pooling exposed and controls together, a positive and significant variation in the urinary mutagenic effect was observed with the number of cigarettes smoked per day.

N-Acetyltransferase Phenotype of Patients with Bladder Cancer

1 N-Acetyltransferase phenotype has been determined in 109 control subjects and in 23 patients with bladder cancer. 2 Sixty-two per cent of control, and 39% of patients with bladder cancer were phenotypically slow acetylators. This difference was not significant. 3 N-Acetyltransferase phenotype is unlikely to be a major determinant in the development of bladder cancer in the Turkish population.

Mercury Exposure in Dental Practice

Since elemental mercury is absorbed by dental professionals through direct skin contact or inhalation, the use of mercury in dental amalgam continues to be a controversial issue. In this study, the authors address the possible health risk of occupational exposure to mercury vapor in the dental office. The cytogenetic examination of leukocytes with alkaline comet assay and blood mercury levels with Atomic Absorption Spectrometer of dentists exposed to mercury vapor below 0.1mg/m(3) concentrations failed to find cytogenetic damage and related correlation. However, higher cytogenetic damage and blood mercury levels evaluated in controls from mercury intake by seafood consumption justifies additional study.

Sister chromatid exchanges in workers employed in car-painting workshops.

SummaryCar painting workers are exposed to a number of potentially genotoxic agents. The frequencies of sister chromatid exchanges (SCEs) were determined in a group of 22 workers involved in painting repaired cars in small workshops. An occupationally non-exposed age-matched group served as controls. There was a significant difference (P < 0.001) in the mean SCE levels in exposed (7.81 ± 1.50) and non-exposed (4.92 ± 0.10) groups. Smoking habit was the other factor most influencing SCE levels. Among both the exposed workers and the controls, smokers had a higher SCE frequency than non-smokers.

Genoprotective role of vitamin E and selenium in rabbits anaesthetized with sevoflurane

In this study, genotoxic effects of repeated sevoflurane anaesthesia were investigated in rabbits with or without antioxidant supplementation. Twenty-one New Zealand male rabbits were included in the study and randomized into three groups as: placebo treated (Group I), vitamin E supplemented (Group II) and selenium supplemented (Group III). Vitamin E and selenium were given intraperitoneally for 15 days before anaesthesia treatment. Anaesthesia was administered using 3% sevoflurane in 4 L/min oxygen for a 3-hour period and continued for 3 days. Blood samples were collected before anaesthesia (Sample 1), after the first, second and third days of sevoflurane administration (Sample 2, Sample 3 and Sample 4 respectively) and the last samples were taken 5 days after the last sevoflurane administration (Sample 5). Genotoxic damage was examined using the comet assay. The degree of damage is assessed by grading the cells into three categories of no migration (NM), low migration (LM) and high migration (HM) depending on the fraction of DNA pulled out into the tail under the influence of the electric field. The number of comets in each sample was calculated (1 × number of comets in category NM + 2 × number of comets in category LM + 3 ×number of comets in category HM) and expressed as the total comet score (TCS), which summarizes the damage frequencies. In Group I, a significant increase in the mean TCSs was observed for Samples 3 and 4 as compared with Sample 1. However, there were no significant differences between Samples 1, 2 and 5. The mean TCS of Sample 4 was significantly higher than Sample 1, 2 and 3 in Group II. Group III demonstrated no significant mean TCSs for any experimental conditions. Statistical differences were also observed between the groups with significant P values. This experimental study points out the presence of DNA damage with repeated sevoflurane anaesthesia and the genoprotective role of antioxidant supplementation on DNA damage in mononuclear leukocytes of rabbits by highly sensitive comet assay.