DNA repair capacity of the colorectal cancer patients and the correlation between the pathological parameters.

BACKGROUND: Colorectal cancers are third most common cancer in both genders. They are associated with genetic and environmental factors. Staging is important in the prognosis. Carcinoembryonic Antigen (CEA) provides preliminary information and there is a correlation between Proliferation Index (PI) and prognostic variables. Our aim is to investigate the relationship between DNA repair capacity and clinico-pathologic factors. PATIENTS AND METHODS: The blood samples taken from cancer patients were irradiated. DNA repair capacity by comet technique was calculated. The CEA values were recorded. Pathology reports were collected and PI values were calculated. s. RESULTS: Total of 30 patients; male (n: 14) and female (n: 16) with a median age of 66.37 ± 10.32 were included. Mean CEA value was 42.85 (1.46 - 422.30 µgr/ml) µgr/ml. Mean % DNA repair capacity was 44.49 ± 5.24. In the pathology; 21 (70%) were T3 tumors; 18 (60%) had lymphatic and 12 (40%) had vascular 2 invasion. Perineural invasion was present in 8 (26.7%). According to the proliferation index (PI); 16 (53.3%) were in high percentile (PI > 66%) group. CONCLUSIONS: There was a significant correlation between; perineural invasion and tumor grade (P = 0.043); lymphatic and perineural invasion (P = 0.006); lymphatic invasion and vascular invasion (P = 0.034) and the DNA repair capacity with the lymphatic invasion (P = 0.026). There was also a statistically significant (P = 0.044) relationship between PI and lymphatic invasion. As a result in colorectal cancer patients DNA repair capacity can be used as a biomarker in the staging and also in the prediction of the tumor behavior.

Comparison of genotoxic effect between smokeless tobacco (Maras powder) users and cigarette smokers by the alkaline comet assay.

Maras powder (MP) is a kind of smokeless tobacco used in the south-eastern region of Turkey and in several other countries of Middle and Far East. The present study was performed to assess the impacts of MP and cigarette smoking on the possible DNA damaging effect. Alkaline comet assay, which is a reliable and an important tool in human biomonitoring studies in the area of genetic toxicology, was used in peripheral lymphocytes of MP users, cigarette smokers, and non-smokers while their frequencies of total comet scores (TCS) were evaluated. The mean TCS (+/-SD) frequency in the peripheral lymphocytes was 14.4 (+/-10.04) for MP users and 8.26 (+/-5.38), 5.94 (+/-3.87) for cigarette smokers (P < 0.05) and non-smoking control subjects, respectively (P < 0.001). There was no significant effect of daily consumption of MP and the duration of MP usage on comet frequencies. In reply to a wrong belief among MP users ("the use of smokeless tobacco product is substantially less hazardous than cigarettes"), the present study shows that the oral use of smokeless tobacco represents a genotoxic hazard which is even higher than the DNA damage observed in cigarette smokers. Therefore, habitual use of MP should be taken into account and could be considered unsafe, equally harmful, and it should not be viewed as a safe alternative to cigarettes.

Determination of DNA damage by alkaline halo and comet assay in patients under sevoflurane anesthesia.

In this study, we report data on the possible genotoxic effect of inhalation anesthetic sevoflurane (SVF) by comparing two techniques, comet and alkaline halo assay, in peripheral blood lymphocytes (PBL) of patients before, during, and after anesthesia and in controls. DNA single strand breaks were detected in PBL of malignant breast cancer diagnosed patients (stage II-III), who were undergoing mastectomy. Blood samples were taken before the induction of anesthesia, at 120 min of SVF anesthesia, and on the postoperative fifth day. The nuclear spreading factor (NSF) for each cell was assessed by alkaline halo assay, and the total comet score (TCS) was evaluated by comet assay. A statistically significant increase (P < 0.0001) was observed in the mean NSF at 120 min of anesthesia (38.24 +/- 14.14) as compared with samples before anesthesia (12.33 +/- 6.14), and the mean NSF was significantly decreased after the postoperative fifth day (17.89 +/- 9.44). Similar results were obtained by the comet assay with significant increase (P < 0.0001) in DNA damage at 120 min of anesthesia (79.66 +/- 15.28) as compared with samples before anesthesia (36.30 +/- 11.39). The DNA damage was almost with the preoperative damage rates after the fifth day of anesthesia (43.40 +/- 12.19). In conclusion, the study points out a reversible genotoxic effect of SVF and the similar DNA damage levels obtained by comet and alkaline halo assay indicate that although halo assay has a completely different principle, it can conveniently be utilized for the assessment of DNA single strand breakage in individual mammalian cells with its experimental advantages.

Oxidative DNA damage and total antioxidant status in rats during experimental gram-negative sepsis.

Sepsis and septic shock remains as leading cause of death in adult intensive care units. It is widely accepted that gram-negative bacteria and their endotoxins cause sepsis and septic shock, predominantly. Enhanced generation of reactive oxygen species may be responsible for tissue injury in septic shock and endotoxemia. The aim of this study was to assess oxidative DNA damage and the total antioxidant status (TAS) in peripheral lymphocytes of rats during different intraperitoneal gram-negative sepsis stages. Adult male Sprague-Dawley rats were divided randomly into four groups. Control group was intraperitoneally inoculated with 2 mL of pyrogene-free saline (Group I, n = 6), and the other rats received an intraperitoneal inoculum with 2 mL of saline containing 2 x 10(8) CFU of Escherichia coli. The animals were killed at time zero (Group I, n = 6), at 6th (Group II, n = 7), 12th (Group III, n = 7), and 24th (Group IV, n = 7) hour after the E. coli inoculation. Oxidative DNA damage in peripheral lymphocytes of rats was evaluated by modified comet assay (single-cell gel electrophoresis). Formamidopyrimidine DNA glycosylase (Fpg) and Endonuclease III (Endo III) were used to detect oxidized purines and pyrimidines, respectively. Total antioxidant quantification was carried out using ABTS+ (2,2'-Azino-di-[3 ethylbenzthiazoline sulphonate]) radical formation kinetics (Randox kit) in serum samples. Significant elevations of basal levels of strand breaks (SB) in Group IV were observed as compared with Group I, II, and III. There was a significant increase in Fpg sites in Group III as compared with Group I and II. However, there was no significant difference in terms of Endo III sites in any of the groups. Although the TAS was decreased with the stages of sepsis, this moderate decrease was significant in only Group IV as compared with Group I. There was no statistically significant correlation between DNA damage and TAS for any of the groups.

The role of antioxidant supplementation in occupational exposure to waste anaesthetic gases.

OBJECTIVES: Although the genotoxicity related to waste anaesthetic gases is controversial, a consistent number of observations have provided evidence for an increased level of DNA strand breaks. The goal of the research was to investigate this hypothesis and estimate the genoprotective role of antioxidant supplementation in technical anaesthesiology staff working in operating theatres. METHODS: Heparinized venous blood samples were collected from 17 exposed technical anaesthesiology staff (mean age 34.3 +/- 3.5 years) and non-exposed control group (mean age 32.2 +/- 3.4 years) and examined in the alkaline comet assay for DNA strand breakage. Vitamin E (300 mg/day) plus vitamin C (500 mg/day) were supplemented to the technical anaesthesiology staff for 12 weeks and blood samples were retaken and evaluated by comet assay. RESULTS: The DNA breakage observed in the lymphocytes of the technical anaesthesiology staff was 21.5 +/- 5.0, as calculated by total comet score (TCS). This score was significantly higher (P<0.001) than in the controls (8.6 +/- 4.7) before antioxidant treatment. Supplementation of vitamins E plus C significantly (P<0.01) reduced the mean TCS as 14.2 +/- 6.1. CONCLUSION: The results of our study indicate that occupational exposure to anaesthetic gases induces oxidative DNA damage. Supplementation of the diet for 12 weeks with vitamin C and vitamin E resulted in a significant decrease in the DNA damage.

Diazepam and propofol used as anesthetics during open-heart surgery do not cause chromosomal aberrations in peripheral blood lymphocytes.

Diazepam is a benzodiazepine with anticonvulsant, anxiolytic, sedative and muscle-relaxing properties. Many aspects of its toxicity have been investigated, including genotoxic and carcinogenic effects in various model systems. However, it is still unclear whether diazepam is in fact a genotoxic agent. Propofol is a rapid-onset, short-acting intravenous anesthetic agent. It is used widely for the induction and maintenance of anesthesia as well as for long-term sedation in intensive care units. There is limited information in the literature on its genotoxic effects. Both drugs are commonly used as anesthetic in patients undergoing open-heart surgery. Therefore, we investigated the possible genotoxic effects of propofol and diazepam in those patients, using a chromosomal aberration (CA) assay. Peripheral blood samples were collected from 45 patients before induction of anesthesia and at the end of the anesthesia with diazepam or propofol. In Group I (n=24), anesthesia was induced with 0.2 mg kg(-1) diazepam and 10 microg kg(-1) fentanyl. In Group II (n=21), anesthesia was induced with 1 mg kg(-1) propofol and 10 microg kg(-1) fentanyl. Pancuronium bromide (0.1 mg kg(-1)) was administered for skeletal muscle relaxation in both groups. Anesthesia was maintained by diazepam administration at 5 mg kg(-1) in Group I or by continuous propofol administration at 2-4 mg (kg h)(-1) in Group II. All patients received 0.02 mg kg(-1) pancuronium and 5 microg kg(-1) fentanyl boluses at 30-40 min intervals for anesthesia maintenance. Body temperature was controlled during bypass in the two groups. We found that the mean frequency of CAs in both groups before and at the end of the anesthesia were not statistically significantly different. Our analysis also indicated that age, smoking habit and gender were not confounding factors. In conclusion, our results indicate that diazepam and propofol do not exert genotoxic effects in blood cells during open-heart surgery.

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.

The role of triple therapy, age, gender and smoking on the genotoxic effects of Helicobacter pylori infection.

The role of age, gender and smoking on both the genotoxic effects of Helicobacter pylori and the efficacy of eradication therapy in a group of patients with gastritis was investigated. Gastritis was confirmed by endoscopy and biopsy, and the presence of H. pylori by urease testing. Pre- and post-treatment peripheral blood lymphocyte cultures were prepared from 17 patients and 25 metaphases per patients were analysed for sister chromatid exchange (SCE), a well-established technique for the evaluation of human exposure to toxic agents. Treatment with omeprazole, clarithromycin and amoxycillin triple therapy eradicated H. pylori in 94% of patients and significantly reduced the SCE frequency. Pre-treatment SCE frequency was found to be positively correlated with age. Female smokers tended to have higher post-treatment SCE frequencies than male smokers, and pre- and post-treatment SCE frequencies were higher in older males than in older females. Eradication therapy decreased the genotoxicity of H. pylori, but age in males and smoking in females may decrease treatment efficacy.

Catechol-O-methyltransferase (COMT) genetic polymorphism in a Turkish population.

Catechol-O-methyltransferase (COMT) inactivates neurotransmitters, catechol hormones and drugs such as levodopa and methyldopa. A low activity allele has been demonstrated at codon 108/158 of the soluble and membrane-bound COMT, respectively, whereby a G to A transition results in a valine to methionine substitution. Ethnic and inter-individual differences in red blood cell COMT activity have been observed in the different populations studied so far. Since, no information is available on inter-individual variability of COMT genotype in Turkish population, we genotyped 217 healthy, unrelated Turkish individuals. The allelic frequencies of COMT gene in the Turkish population were found to be the same as has been observed in Caucasians, but different from Orientals.

Determination of coumarin metabolism in Turkish population.

Cytochrome P450 2A6 is an important human hepatic P450 which activates precarcinogens and oxidizes some drug constituents such as coumarin, halothane, and the major nicotine C-oxidase. Genetic polymorphism exists in the CYP2A6 gene. CYP2A6*1 (wild type) is responsible for the 7-hydroxylation of coumarin. The point mutation (T to A) in codon 160 leads to a single amino acid substitution (Leu to His) and the resulting protein, CYP2A*2 is unable to 7-hydroxylate coumarin. Gene conversion in exons 3, 6, and 8 between the CYP2A6 and the CYP2A7 genes creates another variant, CYP2A6*3. In this study, healthy male and female Turkish volunteers (n = 50) were administered 2 mg coumarin, and urine samples were analyzed for their content of the coumarin metabolite, 7-hydroxycoumarin (7OHC), by high-performance liquid chromatography (HPLC). Genetic polymorphism for CYP2A6 was detected by using two-step polymerase chain reaction (PCR) to identify CYP2A6*1, CYP2A6*2, and CYP2A6*3 in 13 of these subjects. The percentage of the dose excreted of total 7OHC in relation to CYP2A6 genotype and excretion of nicotine/cotinine was also evaluated to demonstrate the role of CYP2A6 in nicotine metabolism. The majority of Turkish subjects (68%) excreted less than 60% of the 2-mg dose as coumarin metabolite. The allelic frequencies were detected as 0.88 for CYP2A6*1 allele; 0.12 for CYP2A6*3 allele in 13 individuals. No heterozygous and homozygous individuals were identified for the CYP2A6*2 allelic variant. Phenotyping and genotyping for drug metabolizing enzymes are of great importance in studies correlating precarcinogen activation or drug metabolism to the CYP2A6 genotype in smoking behavior when populations are investigated.

Comparison of genotoxicity of sevoflurane and isoflurane in human lymphocytes studied in vivo using the comet assay.

In the present paper, we report data on the possible genotoxic properties of two inhalation anaesthetics--sevoflurane (SVF) and isoflurane (ISF) - in peripheral blood lymphocytes of patients before, during and after anaesthesia as compared to an unexposed control group. Both anaesthetics were evaluated for genotoxic activity using the comet assay. The exposed groups consisted of 24 ASA grades 1-2 unpremedicated patients (aged 20-66 years, anaesthetized 115-162 min for elective lower abdominal surgery), while the control group consisted of 12 healthy individuals. After induction of anaesthesia (thiopenthone sodium 5-7 mg/kg, fentanyl citrate 0.1mg and vecuronium bromide 0.1mg/kg), anaesthesia was maintained with inhalation of SVF 1-1.5% (n=12) or ISF 1-1.5% (n=12) in oxygen-air mixture. Venous blood samples were obtained before the induction of anaesthesia, at 60 and 120 min of anaesthesia and on the first, third and fifth days following anaesthesia. The comet assay detects DNA damage which includes strand breaks and alkaline labile sites induced directly by genotoxic agents as well as DNA degradation due to cell death. One hundred cells from each sample were examined and graded as no tailed, short and long tailed nuclei. The mean comet response was not different between controls and patients before anaesthesia. However, similar significant increases were observed in the mean comet response in blood sampled from patients at 60 (36.5+/-11.2, 37.8+/-12.1), or 120 min (53.1+/-17.1, 50.0+/-12.2) of anaesthesia and on the first day (37.8+/-15.1, 35.2+/-15.7) after anaesthesia in SVF and ISF treated groups, respectively. Removal of the DNA damage was observed after the third day of anaesthesia and the repair was completed within 5 days. The DNA damage detected in lymphocytes of patients during anaesthesia with SVF or ISF showed similar results as demonstrated by an increased mean comet migration at 120 min of anaesthesia and the cells were able to repair the induced DNA damage completely on the fifth postoperative day.

Assessment of DNA strand breakage by comet assay in diabetic patients and the role of antioxidant supplementation.

Diabetes patients often show increased production of reactive oxidative species (ROS) together with vascular complications. The presence of these ROS may lead to increased DNA damage in peripheral blood lymphocytes that may be revealed by the comet assay. To test whether DNA is damaged in diabetes, peripheral blood samples were taken from 30 control individuals and 63 diabetic patients (15 insulin dependent (IDDM) and 48 non-insulin dependent (NIDDM)) and the alkaline comet assay was used to evaluate background levels of DNA damage. Significant differences were detected between control and diabetic patients in terms of frequencies of damaged cells. The extend of DNA migration was greater in NIDDM patients by comparison with IDDM patients which might indicate that IDDM patients are handling more oxidative damage on a regular basis. Smoker individuals had higher frequencies of cells with migration by comparison with the non-smokers in both groups. Also, clear differences between patients on placebo and on Vitamin E supplementation for 12 weeks were observed on the basis of the extend of DNA migration during single cell gel electrophoresis.

Influence of GSTM1 genotype on comet assay and chromosome aberrations after induction by bleomycin in cultured human lymphocytes.

Investigators have demonstrated that the mutagen sensitivity assay, based on the quantification of bleomycin (BLM)-induced chromatid breaks in short-term cultured peripheral lymphocytes, can be a marker of cancer susceptibility. Although many factors can contribute to variability in human biomonitoring studies, genetic susceptibility (the influence of polymorphic metabolising genes on response to environmental mutagens) should be considered whenever appropriate. Glutathione-S-transferases (GSTs) encode a family of detoxifying phase II enzymes catalysing the conjugation of glutathione to electrophilic compounds. Studies on Caucasians indicate that about 45% of individuals lack the glutathione-S-transferase M1 (GSTM1, null) enzyme, and are therefore, theoretically at a higher risk to the toxic effects of chemicals. The aim of the present study was to investigate this hypothesis further by evaluating whether the GSTM1 genotype influences the background [corrected] level of DNA damage and the induction of chromosomal aberrations by BLM in peripheral-blood lymphocytes. The alkaline comet assay was used to evaluate background levels of DNA damage in unstimulated lymphocytes while standard cytogenetic techniques were used in mitogen-stimulated lymphocytes treated with BLM. Without BLM treatment, individuals with the GSTM1 null genotype had no significant difference in frequencies of damaged cells by comparison to individuals with the GSTM1 genotype. Also, no significant differences between the two groups of individuals (GSTM1 positive and GSTM1 null) were observed for BLM-induced chromosomal aberrations.

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.

Chromosomal aberrations and alkaline comet assay in families with habitual abortion.

Within the pathology of human reproduction, genetic abnormalities play an important role in spontaneous abortions. This paper describes the morphologic, karyotypic features of a consecutive series of singleton spontaneous abortions collected as part of this study and also reports the application of the alkaline comet assay to assess levels of DNA damage in 31 couples comprised of 13 control couples and a patient group of 18 couples with a history of more than one fetal loss. For the cytogenetic analyses, the conventional lymphocyte culture method was applied to all subjects. In this analysis, two women with habitual abortion were determined to carry balanced chromosomal translocation. The alkaline comet assay (single cell gel electrophoresis technique) was applied also to lymphocytes. The comparison of the results of alkaline comet assay in patient and control individuals showed a significant difference in the number of damaged cells. The cells were evaluated according to their grades of damage as: normal (undamaged-no migration), limited migration, (at low damage level) and extensive migration (comet imaged cells-with increasing numbers of breaks, DNA pieces migrate freely into the tail forming a comet image). The frequency of limited migrated and extensive migrated cells in the women in the patient group were higher than in the women in the control group (p<0.001). However, all above parameters were equal for husbands in both the control and patient group (p>0.05).

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.

Evaluation of genotoxic potential of styrene in furniture workers using unsaturated polyester resins.

Styrene is a widely used chemical, mostly in making synthetic rubber, resins, polyesters, plastics and insulators. Increasing attention has been focused on this compound since experiments using cytogenetic end-points have implicated styrene as a potential carcinogen and mutagen. In order to perform biological monitoring of genotoxic exposure to styrene monomer, we evaluated the urinary thioether (UT) excretion, and sister chromatid exchanges (SCEs) and micronuclei (MN) in peripheral lymphocytes from 53 furniture workers employed in small workplaces where polyester resin lamination processings were done and from 41 matched control subjects. The mean air concentration of styrene in the breathing zone of workers was 30.3 ppm. As a metabolic marker for styrene exposure, mandelic acid + phenylglyoxylic acid was measured in the urine and the mean value was 207 mg/g creatinine. The mean +/- SD value of UT excretions of workers was 4.43 +/- 3.42 mmol SH-/mol creatinine and also mean UT for controls was found to be a 2.75 +/- 1.78 mmol SH-/mol creatinine. The mean +/- SD/cell values of SCE frequency in peripheral lymphocytes from the workers and controls were 6.20 +/- 1.56 and 5.23 +/- 1.23, respectively. The mean +/- SD frequencies (%o) of MN in the exposed and control groups were 1.98 +/- 0.50 and 2.09 +/- 0.35, respectively. Significant effects of work-related exposure were detected in the UT excretion and SCEs analyzed in peripheral blood lymphocytes (p < 0.05 and p < 0.01, respectively). The MN frequency in lymphocytes from the styrene-exposed group did not differ from that in the controls (p > 0.05). Effect of smoking, age and duration of exposure on the genotoxicity parameters analyzed were also evaluated. In conclusion, although our data do not demonstrate a dose-response relationship, they do suggest that styrene exposure was evident and that this styrene exposure may contribute to the observed genotoxic damage in furniture workers.

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.

Trimethylamine N-oxidation in Turkish women with bacterial vaginosis.

Bacterial vaginosis (BV) is the most common cause of vaginal discharge in women of child-bearing age. A common symptom of this condition is a fishy-smelling vaginal discharge. Trimethylamine (TMA) is the substance which is primarily responsible for this distinctive odour. The ability to metabolize TMA is polymorphically distributed such that the majority of individuals metabolize a large part of the body burden of TMA to the odourless trimethylamine N-oxide (TMAO) which is excreted in urine with a small amount of TMA. However, in certain individuals, N-oxidation of TMA is impaired which results in the excretion of large amounts of TMA in the urine, breath, sweat and vaginal secretions. In the present study the metabolism of TMA to TMAO was determined in women with clinically diagnosed BV, women with fishy-smelling vaginal discharge but with no other evidence of BV and control women with no evidence of fishy-smelling vaginal discharge. An index of TMA N-oxidation was established for all subjects after analysis of a 24 h urine sample for free TMA and total TMA after reduction of TMAO. We show that, irrespective of diagnosis of BV or not, women with fishy-smelling vaginal discharge excrete significantly more free TMA and have a similarly significantly reduced capacity to N-oxidize TMA when compared to healthy control women. Thus, the results of this study suggest that a woman's ability to metabolize TMA to TMAO is an important factor which predisposes to a fishy-smelling vaginal discharge.

Assessment of smoking-induced DNA damage in lymphocytes of smoking mothers of newborn infants using the alkaline single-cell gel electrophoresis technique.

The single-cell gel electrophoretic (SCGE) technique for detecting the presence of DNA strand breaks and alkali-labile damage in individual cells was used to examine the effect on newborn infants of maternal exposure to cigarette smoke. The levels of DNA damage in the lymphocytes of 21 newborns of mothers with different smoking habits were compared to those in 10 newborn infants whose mothers had never smoked and 8 newborns whose mothers were passively exposed for at least 40 h per week in the workplace and home. DNA damage was undetected in lymphocytes of newborns of passively exposed mothers or newborns with mothers of low smoking habit by conditions allowing 40 min DNA unwinding and 40 min electrophoresis. Presumably longer times were needed for lower levels of damage to be detected by SCGE. The mean length of DNA migration in lymphocytes between the newborns of smoking mothers did not show any significance but the percentage of damaged cells increased with the frequency of smoking when assessed by non-parametric Mann-Whitney U test. The results of SCGE were compared with our results published in the same individuals of sister-chromatid exchange (SCE) frequency. The results show similar trends with mean measures of DNA damage increasing with frequency and long history of maternal smoking. These observations encourage the application of SCGE as a sensitive and useful technique for quantitating DNA damage in individual cells.