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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

The effect of smoking on sister chromatid exchange rate of newborn infants born to smoking mothers

Sister chromatid exchange (SCE) frequencies in lymphocytes of 21 smoking mothers and their 21 newborns were compared to those that of 10-infants whose mothers had never smoked and to those of 8 infants whose mothers were passive smokers and reported high exposure to tobacco smoke by living or working with smokers. Mothers in the first group also smoked throughout their pregnancy. Results confirm our earlier study on smoking effects reported for adults. Additionally, we saw that neonates have consistently lower SCE frequencies than adults.

Sister-chromatid exchanges in epileptic patients on anticonvulsant therapy

Sister-chromatid exchanges (SCE) have been studied to analyze genotoxic effects in epileptic patients on anticonvulsant therapy. All patients had an increased frequency of SCE per metaphase (p < 0.001) compared to controls, indicating a genotoxic effect of anticonvulsant drugs.

Sister chromatid exchange studies for monitoring DNA damage in lymphocytes of malignant lymphoma patients under cytostatic therapy

Sister chromatid exchange (SCE) frequencies were studied in lymphocytes from 45 patients with malignant lymphoma. Fifteen patients were untreated when studied. The mean SCE frequency for these patients was 8.70 +/- 0.99 per mitosis. The mean score for 35 controls was 4.37 +/- 1.19. SCE mean scores were significantly higher in the untreated patients than in the controls (p < 0.001). Nine patients were treated with radiotherapy alone. The mean SCE frequency (6.80 +/- 0.87) they demonstrated was significantly lower (p < 0.01) than that found in untreated patients. Twelve patients received cyclophosphamide 1 month before the study was started. They demonstrated a mean SCE frequency (12.00 +/- 1.31) significantly higher (p < 0.05) than that found in patients who had received regimens that did not contain cyclophosphamide (9.72 +/- 1.32). From these findings we suggest that untreated patients with malignant lymphoma have elevated SCE frequencies, which may be further increased by chemotherapeutic agents.

Mutagenic risk in psoriatic patients before and after 8-methoxypsoralen and long-wave ultraviolet radiation

Sister-chromatid exchange (SCE) analysis was carried out in different age groups prior to and after therapy with 8-Methoxypsoralen (8-MOP) followed by exposure of the patient to long-wave UV-A (PUVA) and compared to control. The SCE frequencies were increased significantly in PUVA-treated patients as compared to their pre-treatment SCE levels and to controls. A significant increase in SCEs was found in smoking PUVA-treated patients as compared to non-smoking PUVA-treated patients. This study indicates a detectable chromosome-damaging effect of PUVA therapy on its human users.

N-acetylation phenotyping with sulfamethazine in an Iranian population

The acetylation polymorphism is one of the most common inherited variations in the biotransformation of drugs and chemicals. Its association with drug toxicity and increased risk of developing certain diseases and certain types of chemically induced cancers has made it one of the oldest and best studied examples of pharmacogenetic conditions. N-Acetylation of sulfamethazine was studied in 74 unrelated healthy Iranian volunteers. The frequency of slow acetylators, determined by using free and total plasma sulfamethazine concentrations, was 78.4%. The mean acetylation ratio was 19.48% for slow acetylators, and the frequency of the recessive allele controlling slow acetylation was found to be 0.88. This percentage is similar to that observed in various Arab countries and higher than that observed in Europeans.

Sister-chromatid exchanges in operating room personnel

Sister-chromatid exchange (SCE) analysis was carried out in 67 operating room personnel (anaesthetists M.D.; anaesthesia nurses and anaesthesia unit technicians) exposed to waste anaesthetic gases such as halothane, nitrous oxide and isoflurane and in 50 healthy unexposed controls. The SCE frequencies were increased significantly in operating room personnel as compared to controls. A significant increase in SCEs was found in non-smoking operating room personnel as compared to non-smoking controls. This study supports the existence of an association between occupational exposure to mutagens and an increase in SCEs in lymphocytes.

Sister chromatid exchanges in lymphocytes of nurses handling antineoplastic drugs

The effects of handling antineoplastic drugs were examined in a group of 23 nurses working in the hematology and oncology departments of different university hospitals in Ankara and in a group of 50 unexposed controls. The cytogenetic repercussions of exposure were assessed by examining sister chromatid exchanges (SCEs) in circulating lymphocytes which result from the breakage and rejoining of DNA at apparently homologous sites on the 2 chromatids of a single chromosome. A significant increased frequency of SCE is observed in nurses in daily contact with antineoplastics (n = 23, mean SCEs/cell +/- SE 6.5 +/- 0.2) as compared to a group of controls (n = 50, mean SCEs/cell 5.2 +/- 0.2). The nurses who smoked also had a higher SCE frequency (n = 15, mean SCEs/cell 7.0 +/- 0.3) than non-smokers, (n = 8, mean SCEs/cell 5.5 +/- 0.3). A significant increase (P less than 0.001) in the mean number of SCE was found for non-smoking nurses as compared to non-smoking controls (n = 27, mean SCEs/cell 4.1 +/- 0.2).

Sister chromatid exchanges in peripheral lymphocytes of urinary tract infection treated with nitrofurantoin

Nitrofurantoin, a widely used antibacterial agent in the therapy of urinary tract infections of bacterial origin, has been widely discussed in recent years due to its genotoxicity. Sister chromatid exchanges (SCE) were studied in lymphocyte cultures of 15 urinary tract infection patients before and after medication with daily oral doses of 10 mg/kg or 400 mg nitrofurantoin for 10 days. Both stages exhibited similar average numbers of SCE in circulating lymphocytes. The number of SCE was larger in smokers. The results of this study suggest that the short-term exposure to nitrofurantoin does not cause detectable cytogenetic abnormalities.