Micronucleus Frequency In Lymphocytes Research Articles

Assessment of micronucleus frequencies in lymphocytes of workers exposed to fumes of bitumen—Results of the human bitumen study

Fumes of bitumen contain small amounts of polycyclic aromatic hydrocarbons (PAH). Some of them are known to be carcinogenic. Therefore a possible genotoxic risk from exposure of workers during hot application of bitumen in mastic asphalt laying is under discussion. In order to address this question we investigated the micronucleus (MN) frequencies in lymphocytes of mastic asphalt workers and reference persons not exposed to bitumen.

Is the genotoxic effect of magnetic resonance negligible? Low persistence of micronucleus frequency in lymphocytes of individuals after cardiac scan

Magnetic resonance imaging is a diagnostic technique widely used in medicine and showing a growing impact in cardiology. Biological effects associated to magnetic resonance electromagnetic fields have received far little attention, but it cannot be ruled out that these fields can alter DNA structure. The present study aimed at to identify possible DNA damage induced by magnetic resonance scan in humans. Lymphocyte cultures from healthy subjects had been exposed into magnetic resonance device for different times and under different variable magnetic exposure in order to build dose-effect curves, using micronuclei induction as biological marker. Replicate cultures were also left for 24 h at room temperature before stimulation, to verify possible damage recovery. Furthermore, micronuclei induction and recovery up to 120 h have been also evaluated in circulating lymphocytes of individuals after cardiac scan. A dose-dependent increase of micronuclei frequency was observed in vitro. However after 24 h, the frequency returns to control value when the exposure is within diagnostic dosage. After in vivo scan, a significant increase in micronuclei is found till 24 h, after the frequencies slowly return to control value.

Enhanced level of micronuclei in peripheral blood lymphocytes of patients treated for restenosis with 32P endovascular brachytherapy

Restenosis is the complete occlusion of the blood vessel leading to such complications as ischemia/angina, myocardial infarction, and death. It can be managed by endovascular brachytherapy with both gamma and beta sources. Endovascular brachytherapy is performed worldwide on several thousands of cases per year. The gamma-emitter 192Ir as well as the beta-emitters 32P and 90Sr are mainly used. The dose to the occluded endothelial wall is 20 Gy. Interestingly, no information with respect to the dose absorbed by the blood during the course of the treatment exists. The aim of the present investigation was to verify if the micronucleus test is suitable to detect the dose absorbed by lymphocytes in the course of endovascular brachytherapy with 32P. Blood was drawn from 16 patients immediately before and 1 day after the treatment. Frequencies of micronuclei were assessed. In order to ensure that the micronuclei did not arise due to fluoroscopy or reperfusion, we analyzed lymphocytes of 16 control patients who underwent interventional cardiology with balloon angioplasty only. Enhanced frequencies of micronuclei were observed in lymphocytes of some donors following brachytherapy. No correlation could be detected between the level of induced micronuclei and the absorbed dose. Also, no effect of fluoroscopy or reperfusion was seen. Thus, although brachytherapy of restenosis with 32P leads to weak enhancement of the micronucleus frequency in lymphocytes, the effect was not seen in all patients; the reason for this heterogeneous response remains to be elucidated.

BIOLOGICAL ESTIMATION OF DOSE IN HEMI-BODY IRRADIATION OF CANCER PATIENTS BY CYTOGENETIC ANALYSIS

The objective of this study was to estimate equivalent whole body dose and dose to the irradiated region in hemi-body irradiation of cancer patients using chromosome aberrations and micronuclei techniques. The frequency of unstable chromosome aberrations and micronuclei was studied in peripheral blood lymphocytes of cancer patients before and after hemi-body irradiation. The mean estimated equivalent whole body dose was 3.74 +/- 0.16 Gy and 4.07 +/- 0.15 Gy from dicentrics and micronuclei frequency in lymphocytes after hemi-body irradiation. The mean dose to the irradiated region from unstable chromosome aberrations was estimated to be 6.85 +/- 0.2 Gy and 6.79 +/- 0.26 Gy using Dolphin's contaminated Poisson dispersion analysis and the Qdr method, respectively. The mean dose to the irradiated region from micronuclei frequency was 7.04 +/- 0.25 Gy by Dolphin's method. There was a slight underestimation of mean dose to the irradiated part in vivo. The percentage of irradiated blood and fraction of the cells exposed could be estimated using the contaminated Poisson method.

Evaluation of micronucleus frequencies in blood lymphocytes from smelting plant workers exposed to arsenic

Arsenic is a world health problem due to the seriousness of its effects, mainly related with the increase of cancer. In Chile, the geological characteristics of the northern region, associated with the development of the copper mining and smelting activities, have contributed to increase the environmental levels of arsenic. This study has been conducted to investigate the relationship between arsenic occupational exposure and genotoxic effects in smelting plant workers. To determine the genotoxic risk related to the increase of cancer among the chronically exposed population, the frequency of micronuclei in blood (BNMN) has been evaluated. The study was carried out in a total of 207 men, divided into three groups: an exposed group of 105 individuals working in a smelting plant, an internal reference group with 52 employees at the same mine but in the administrative area, and an external reference group of 50 workers from another copper mine where no significant levels of arsenic were detected. As expected, differences between arsenic levels in urine have been detected between groups, with the exposed group being the one with a higher level of total arsenic in urine, followed by the internal reference group. Despite that, no significant differences in micronuclei frequencies in lymphocytes were detected among these groups.

Basal level micronucleus frequency in stimulated lymphocytes of untreated patients with leukemia

Structural chromosomal aberrations have been described in various types of human leukemia. The micronucleus technique provides a measure of both chromosome breakage and chromosome loss. The present study investigated micronucleus (MN) frequency in mitogen-stimulated peripheral blood lymphocytes from 20 newly diagnosed and untreated leukemia patients: 4 with acute lymphoblastic leukemia (ALL), 10 with acute myeloid leukemia (AML), and 6 with chronic lymphocytic leukemia (CLL).The mean MN frequency for untreated patients was 3.65 ± 1.47 in ALL, 3.55 ± 1.24 in AML, 3.03 ± 1.05 in CLL. No differences in MN frequency were seen between leukemia types ALL, AML, and CLL ( P = 0.503). The mean basal MN frequency for all patients, regardless of leukemia type, was 3.41 ± 1.19, which was significantly higher ( P = 0.001) than that of 20 age-matched control subjects, 1.87 ± 0.75. Although no significant relationship was found between age and MN frequency in patients with leukemia ( r = 0.050; P = 0.835), the MN frequency in the lymphocytes of healthy control increased regularly and significantly with age ( r = 0.531; P = 0.016). These data indicate that the increased baseline MN frequency in lymphocytes of untreated patients with leukemia may reflect genomic instability or deficiency of DNA repair capacity. MN enhancement in this disease may thus be a consequence of the disease process.

The cytokinesis-block micronucleus assay as a biological dosimeter for targeted alpha therapy

Ionizing radiation causes structural chromosomal aberrations, a proportion of which give rise to chromosome fragments without spindle attachment organelles. When a cell divides, some of these fragments are excluded from the main daughter nuclei and form small nuclei within the cytoplasm. The cytokinesis-block micronucleus assay allows these micronuclei (MN) to be counted, providing an in situ biological dosimeter. In this study, we evaluated the micronucleus frequency in peripheral blood lymphocytes after in vitro incubation with the alpha conjugates 213BiI3 and 213Bi-9.2.27 (AIC). Lymphocytes were inoculated in vitro AIC for 3 h. Further, we report the first MN measurements in melanoma patients after targeted alpha therapy (TAT) with 213Bi-9.2.27. Patients were injected with 260–360 MBq of AIC, and blood samples taken at 3 h, 2 weeks and 4 weeks post-treatment. Absorbed dose (MIRD) and effective total body dose (PED) were calculated. The MN frequency in lymphocytes was similar for equal in vitro incubation activities of 213BiI3 and 213Bi-9.2.27 (P = 0.5), indicating that there is no selective targeting of lymphocytes by the alpha conjugates. After inoculation with 10–1200 kBq mL − 1 of AIC, there was a substantial activity-related increase in MN. The number of MN in the blood of treated patients peaked at 3 h post-TAT, slowly returning to baseline levels by 4 weeks. The mean photon equivalent dose (PED) is 0.43 Gy (SD 0.15) and the mean MIRD calculated absorbed dose is 0.11 Gy (SD 0.03), giving an RBE = 4 ± 0.4 for this study.

Exposición a Solventes Orgánicos y Efectos Genotóxicos en Trabajadores de Fábricas de Pinturas en Bogotá

Investigating the degree of exposure to organic solvents and related genotoxic consequences in paint-factory workers by using cytogenetic monitoring and determining micronuclei frequency in lymphocytes and DNA damage as assessed by comet assays. Excretion of phenol and hippuric and methylhippuric acids in urine was investigated as biomarkers for benzene, toluene and xylene exposure. Urine samples were taken in two paint-factories in Bogotá and in a non-exposed control group. Benzene, toluene and xylene concentrations in air were measured in the work setting. Micronuclei and simple DNA chain breakage frequency were evaluated in peripheral blood sample mononuclear cells to assess early genetic effects. Hippuric acid concentration was found to be within normal values; by contrast, phenol and methylhippuric acid sample concentrations were above normal values by 3,3 % and 50,8 %, respectively. Benzene concentration in air was above permissible limits in one of the factories. There were no statistical differences regarding genetic biomarkers between exposed and non-exposed workers. Organic solvent levels in the samples were apparently low, which is consistent with the absence of genotoxicity in cells. This study represents a step forward in research in occupational health surveillance.

Analysis of telomere damage by fluorescence in situ hybridisation on micronuclei in lymphocytes of breast carcinoma patients after radiotherapy

Radiotherapy has become an indispensable tool in the effective management of most of the cancers. There have been efforts earlier to study the differential radio-sensitivity patterns in patients undergoing radiation treatment to correlate with treatment induced complications such as tissue injury, cell death, and chromosomal aberration frequencies etc. The present study is an attempt to correlate the radiation-induced damage in the peripheral blood lymphocytes (PBLs) of breast cancer patients with the frequency of telomere mediated chromosomal damage. Blood samples from 55 patients with (Gr-II and Gr-III) CA-breast were obtained pre- and post-radiotherapy. The patients were treated with external beam radiotherapy of 50.4 Gy over a period of 6 weeks. Chromosome damage was measured by analysing micronucleus (MN) frequency in PBLs. The MN-frequency of the irradiated patients increased significantly compared to the patients being self-controls. The micronuclei were hybridized with telomere probes to study the extent of telomere damage. The fluorescence signals of the telomere regions in the first generation of the binucleated cells were significantly higher in the post-radiotherapy patients. There was also significant correlation observed in the patients with higher-grade tumours. Inter-individual variability was observed in the radiation-induced MN frequency in lymphocytes of patients after six weeks of radiotherapy. There was a significant correlation between functionally intact telomeres and the cellular response to ionising radiation. Our findings suggest that fluorescence in situ hybridisation on micronuclei could be effectively used as routine clinical application to determine the individual sensitivity to ionising radiation with respect to telomere damage.

Investigation of micronucleus frequencies in lymphocytes of inhabitants environmentally exposed to chrysotile asbestos

Exposure to asbestos minerals has been associated with a wide variety of adverse health effects including lung cancer, pleural mesothelioma, and cancer of other organs. Many of the regions of Turkey have asbestos deposits. People in Doğanlı village – one of these regions – have been environmentally exposed to chrysotile asbestos since they were born. In this study the effects of asbestos on micronucleus (MN) frequencies of inhabitants exposed to chrysotile asbestos have been examined. Thirty subjects who had been environmentally exposed to chrysotile asbestos and living in Doğanlı village, and 25 controls were studied to assess the MN frequency. The control group was selected from healthy individuals with no exposure to asbestos and living in similar geographic conditions to Doğanlı village. Peripheral blood samples were collected from each subject and cultured for MN assay. Cytochalasin-B was added to lymphocyte cultures for evaluation of MN in binucleated (BN) cells. The differences between those exposed to chrysotile asbestos and controls were not statistically significant in terms of BN cells with MN (p > 0.05). There was not a significant relationship between MN frequencies and age, sex, smoking, both in chrysotile asbestos-exposed subjects and in controls (p > 0.05). Although the detection of calcified pleural plaques found in the inhabitants has indicated environmental exposure to chrysotile asbestos, our results show that chrysotile asbestos was not an inducer of MN in subjects exposed to chrysotile asbestos.

Micronuclei in Cord Blood Lymphocytes as a Biomarker of Transplacental Exposure to Environmental Pollutants

Exposure to environmental pollutants can result in chromosomal instability, which can produce a wide variety of effects on human health. In the spring of 1999, extensive environmental pollution happened in Kragujevac (the city in the central Serbia) with damages of soil, water and air, caused by the air strikes on "Zastava" complex. Because we found significant increase of micronuclei in newborns born 12 months after this environmental pollution (in the beginning of 2000), the purpose of the present study was to follow the frequency of micronuclei in lymphocytes of newborns born seven years after pollution (in 2006). The frequencies of micronuclei were estimated in cord blood lymphocytes of 41 newborns (20 males and 21 females) by application of cytokinesis-block (CB) micronucleus test. The obtained results showed that the mean value of micronuclei was significantly decreased in newborns born in 2006 in comparison to the mean value of micronuclei in newborns born 12 months after contamination (4.73 +/- 3.38 micronuclei/1,000 CB cells vs 9.36 +/- 5.60 micronuclei/1,000 CB cells), with probability p < 0.001. Newborn's gender, mother's age (19-40 years) and maternal cigarette smoking (< 20 cigarettes per day) did not show any noticeable effects on micronuclei frequencies in the analyzed newborns. There was relationship between the micronuclei frequencies and the level of environmental pollution (F = 6.95, p = 0.000). Our results suggest that the environment profoundly influences genetic constitution of newborns, and that micronucleus assay in cord blood lymphocytes is an important method for evaluation of transplacental mutagens.

The relationship between micronuclei in human lymphocytes and selected micronutrients in vegetarians and non-vegetarians

A vegetarian diet results in higher intake of vitamins and micronutrients, which – although providing antioxidant defence – may lead to deficiency in other micronutrients involved in DNA metabolism and stability (such as vitamins belonging to the B group). The principal difference among various vegetarian diets is the extent to which animal products are avoided. We have performed a pilot study to determine the relationship between the micronucleus frequency in lymphocytes and diet, and we compared the levels of Vitamins C and E, β-carotene, B 12, folic acid, homocysteine and total antioxidant capacity in healthy vegetarians and non-vegetarians. The vegetarian group, consisting of 24 volunteers (13 women and 11 men), were matched for age and sex with 24 volunteers (12 women and 12 men) with a traditional dietary habit. Among the vegetarians were 13 lacto-ovo-vegetarians with average duration of vegetarian diet 10.8 years (ranging from 5 to 26 years) and 11 lacto-vegetarians with average duration of vegetarian diet 8.2 years (ranging from 3 to 15 years). Homocysteine, Vitamins C and E and β-carotene levels in plasma were assayed by HPLC, and serum folate and Vitamin B 12 were determined with Elecsys Immunoassay tests. The total antioxidant capacity of plasma was estimated by measuring the ferric-reducing activity in a spectrophotometric assay. Micronuclei were measured in cytokinesis-blocked lymphocytes. Vegetarians had significantly higher levels of Vitamin C and β-carotene (but not Vitamin E) in plasma compared with non-vegetarians ( P < 0.001). There were no significant differences in serum levels of folic acid and Vitamin B 12 between the monitored groups. Levels of folic acid in vegetarians correlated with length of vegetarianism ( r = 0.62, P = 0.001, N = 24). Vegetarians had elevated levels of homocysteine compared with non-vegetarians ( P = 0.007), as did vegetarian women compared with non-vegetarian women ( P = 0.031). We did not find any differences in total antioxidant capacity or in micronucleus frequency between the groups. Micronuclei correlated with age ( r = 0.62, P < 0.001, N = 48), women having higher frequencies than men. Multifactorial regression analysis showed significant effects of age, sex and total antioxidant capacity on micronucleus frequency ( N = 48, P < 0.001).

Micronuclei Frequency in Lymphocytes and Antioxidants in the Blood of Traditional Limited-Resource Farm Workers Exposed to Pesticides

Chronic low-level exposure to synthetic pesticides is implicated in many health conditions that result from the induction of oxidative stress, including cytogenetic damage. The objective of this study was to assess the risk of genotoxicity using micronuclei (MN) formation in lymphocytes and to determine changes in blood antioxidants superoxide dismutase (SOD) in erythrocytes (E) and glutathione (GSH) in E and plasma (PL) in farm workers for six months during a growing season. Blood and urine samples were collected once a month for six months (June to November 2003) from farm workers (n = 15) and urban unexposed controls (n = 10). Lymphocytes from blood were separated by density gradient centrifugation using Histopaque and cultured using the standard technique. There was no significant difference in the cytokinesis blocked proliferation index (CBPI) of lymphocytes between the farm workers and the control group, but there was a 76% increase in average MN frequency in lymphocytes of the farm worker group (P ≤ 0.05). In addition, MN frequency peaked during August as compared to the other months and the controls (P ≤ 0.05). An 18% decline was observed in the activity of E-SOD in the farm worker group (P ≤ 0.05). GSH in E and PL were similar in both groups. These data suggest that the farm workers may be at a greater risk of developing genotoxicity due to continued exposure to pesticides, especially during the intensive growing season.

Micronucleus frequency in women with genital Chlamydia Trachomatis infection before and after therapy

The main aim of the present study was to investigate the influence of infection with the intracellular bacterium Chlamydia trachomatis, and subsequent treatments with oral doxycycline or azithromycin on the frequency of micronuclei (MN) in peripheral blood lymphocytes of adult female patients receiving standard doses of these drugs. The frequency of micronuclei was measured in the lymphocytes of 38 newly diagnosed adult women with genital C. trachomatis infection. Samples were taken before and after the therapy, and from 50 healthy control females. The therapy was taken orally during 10 days at 2 × 100 mg per day, and then for another 10 days at 1 × 100 mg per day for doxycycline, and as a single dose of 1 g for azithromycin. Isolated lymphocytes from all subjects were cultured by use of the whole-blood method and blocked in metaphase with cytochalasin B (Cyt B). One thousand binucleate cells per subject were scored according to published criteria. The frequency of micronuclei was not significantly higher in samples of infected females before therapy, compared with the baseline frequency in healthy control females ( p > 0.05). In patients who received doxycycline, the micronucleus frequency after the end of therapy was significantly higher than before treatment ( p < 0.001). The mean frequency of micronuclei in females after the end of the therapy with azithromycin did not show an increase ( p > 0.05). The application of linear regression analysis showed that the difference in micronucleus frequency before and after therapy (effect of the antibiotics) was affected by the therapy type. Age and smoking did not affect micronucleus frequency in analyzed samples of patients ( p = 0.078, 0.579). We conclude that C. trachomatis infection does not induce micronuclei in peripheral blood lymphocytes of infected adult female patients. Therapy with doxycycline significantly increases the micronucleus frequency in lymphocytes of treated patients, but treatment with azithromycin does not induce micronuclei.

Application of a geographic information system to explore associations between air pollution and micronucleus frequencies in African American children and adults

Exposure to air pollution has been associated with adverse respiratory and cardiovascular health outcomes in both children and adults. In this study, we used geographic information systems (GISs) to explore possible associations between chromosomal damage in 65 African American children and their mothers from Oakland, California, and both proximity to traffic and regional ozone levels. Study participants were interviewed at the Healthy Child Clinic of Children's Hospital, Oakland, and their blood and buccal cells were collected for assessment of chromosomal damage by the micronucleus (MN) assay. Regional ozone levels, which decreased from April to November with a secondary peak in late summer, were highly correlated with season by month (r=-0.84, P=0.02) and strongly associated with MN frequency (frequency ratio (FR): 3.37, 95% confidence interval (CI): 1.30-8.72) in both cell types of children and adults. Additionally, MN frequencies were modestly associated with individual measures of traffic density in children (FR=2.45, 95% CI=0.86-7.10), but not in adults; this suggests a greater vulnerability to traffic-related air pollution in children. Smoking in the household also increased MN frequency in the lymphocytes of children (FR: 1.13, 95%CI: 1.01-1.24) and adults (FR: 1.06, 95%CI: 0.99-1.13), whereas vitamin use in adults decreased MN frequency in both lymphocytes and buccal cells (FR: 0.17, 95%CI: 0.02-1.31; FR: 0.18, 95%CI: 0.03-1.18, respectively). Our data indicate that GIS-generated measures of traffic density for individual households augment regional ozone monitoring data used to assess effects of air pollution. This approach helped to demonstrate elevated cytogenetic damage in exposed minority children.

Association of ALDH2 polymorphism with sensitivity to acetaldehyde-induced micronuclei and facial flushing after alcohol intake

To investigate whether sensitivity to the induction of micronuclei by acetaldehyde is associated with genetic polymorphisms of the aldehyde dehydrogenase-2 ( ALDH2) gene, cytokinesis-block micronucleus (CBMN) assays were performed on peripheral lymphocytes from 47 healthy human subjects exposed to acetaldehyde in vitro. Facial flushing following alcohol intake was analyzed to determine if it was correlated with ALDH2 gene polymorphisms. The frequencies of the ALDH2 genotypes ALDH2 1/ALDH2 1, ALDH2 1/ALDH2 2, and ALDH2 2/ALDH2 2 were 66.0, 27.7, and 6.4%, respectively, in the 47 subjects. Therefore, 34% of the studied subjects carried the mutant allele ALDH2 2, which is associated with the lack of enzyme activity. The frequency of micronuclei induced by acetaldehyde increased in a dose-dependent manner with the largest increase seen in subjects that were homozygous for the ALDH2 2 allele. A significant association was observed between the ALDH2 genotype and alcohol-induced facial flushing. Average alcohol consumption of the study subjects was also associated with the ALDH2 genotype. The frequency of heavy drinking was significantly higher among subjects with the ALDH2 1/ALDH2 1 genotype than among subjects with the ALDH2 2 allele (ALDH2 1/ALDH2 2 and ALDH2 2/ALDH2 2 genotypes). Alcohol-induced facial flushing was also associated with an increased frequency of micronuclei in lymphocytes treated with acetaldehyde. The results suggest that the ALDH2 genotype is significantly associated with acetaldehyde-induced micronuclei and alcohol-induced facial flushing.

Increased incidence of micronuclei assessed with the micronucleus assay and the fluorescence in situ hybridization (FISH) technique in peripheral blood lymphocytes of nurses exposed to nitrous oxide

It has been postulated that exposure to nitrous oxide and halogenated anaesthetics is associated with various adverse health effects such as neurological and reproductive abnormalities or impairment of hepatic functions. In spite of the quite well known genotoxic effects of exposure to nitrous oxide in vivo, the mechanisms of these effects are still not clear. The aim of this study was to assess the frequency of micronuclei and to identify the type of chromosomal damage (clastogenic or aneugenic) in peripheral blood lymphocytes of operating-room nurses exposed to nitrous oxide. The study group comprised 46 women working at departments where the concentration of nitrous oxide ranged from 14 to 2308 mg/m 3. The control population was composed of 28 women employed in the same hospitals but in non-surgical departments. The clastogenic/aneugenic effect of nitrous oxide was evaluated in lymphocytes using the standard micronucleus (MN) assay in combination with the fluorescence in situ hybridization (FISH) technique with pancentromeric probes. The results show a significant increase of the MN frequency in lymphocytes of exposed nurses compared with the control group (4.36 ± 2.23 versus 9.02 ± 4.67). The multiple regression analysis revealed a statistically significant relationship ( p = 0.0009) between MN frequency and exposure status, indicating that the level of exposure was the main factor affecting chromosomal damage. As assessed by FISH analysis, the overall frequencies of centromere-positive MN in the control and exposed groups were 43 and 49%, respectively. The increase observed in the exposed group may suggest a slight, statistically insignificant pro-aneugenic effect of exposure to nitrous oxide.

Micronuclei in peripheral blood lymphocytes of workers exposed to lead

Lead plays an important role in many industrial processes. Although highly useful to man, lead has various types of toxic effects. There is constantly growing evidence of a relationship between the induction of chromosome breaks and an increased risk of onset of cancer. However, available data about the possible genotoxic and carcinogenic action of lead are conflicting. In this report we present the results of studies on lead concentrations in blood and the respective micronucleus frequencies in peripheral blood lymphocytes from workers employed in the recycling of automotive batteries in the surroundings of Porto Alegre, Brazil. We observed that in the occupationally exposed group, both lead concentration in peripheral blood and micronucleus frequency in lymphocytes were significantly higher compared to control ( Z = 6.35, P < 0.0001 and Z = 4.47, P < 0.0001). The nuclear division index (NDI) values were significantly higher in the control group than in the exposed group ( Z = 2.13, P = 0.0330), indicating a possible effect of Pb on nuclear proliferation. We also detected a negative correlation between micronuclei and progression of nuclear division ( τ = −0.312, P = 0.0129). There were no changes in micronucleus frequency between smoking and non-smoking workers exposed to lead ( Z = 0.03, P = 0.9790). The only difference found between the groups of smokers and non-smokers was with respect to NDI, whose values were significantly higher among non-smokers ( Z = 1.98, P = 0.0481).

The Frequency of Micronuclei among Newborns from Kragujevac, Central Serbia, after NATO Bombing in the Spring of 1999

Kragujevac, as an important industrial and economic center of the region, is now placed on the top of the list of environmentally endangered cities in our country. The aim of this biomonitoring study was to evaluate cytogenetic damage in a sample of newborns from Kragujevac after contamination of the environment entailed by the intensive bombing of the industrial zone of this city in the spring of 1999. The frequency of micronuclei (MN) in peripheral blood lymphocytes in a total of 61 phenotypically healthy newborns was analyzed before and after the NATO bombing. Analysis of micronuclei has been performed using the cytokinesis-block technique (CB MN test). Average MN frequency in lymphocytes of newborns before the bombing (N = 25) was 5.77 ± 0.85/1000 analyzed cells. After the bombing (N = 36), the average frequency of MN increased by a factor of 1.4 (8.11 ± 0.85), compared to the control frequency before the bombing. Statistical difference (p < 0.05) was established by Student's t-test. Our data suggest that such changes in genetic material were a direct consequence of contamination of the living environment.

Radiation-induced micronucleus frequency in peripheral blood lymphocytes is correlated with normal tissue damage in patients with cervical carcinoma undergoing radiotherapy.

In an effort to find a test to predict the response of normal tissue to radiotherapy, the lymphocyte micronucleus assay was used on blood samples from patients with cervical carcinoma. Peripheral blood samples from 55 patients with advanced-stage (II B-IV B) cervical carcinoma were obtained before radiotherapy. The patients were treated with external-beam radiotherapy followed by high-dose-rate brachytherapy. Acute and late normal tissue reactions were scored and correlated with the micronucleus frequency in lymphocytes after irradiation with 4 Gy in vitro. Great interindividual variability was observed in the radiation-induced lymphocyte micronucleus frequency, especially at 4 Gy. The mean number of micronuclei per 100 binucleated cells in cells irradiated with 4 Gy in vitro was significantly higher in samples from patients who suffered from acute and/or late normal tissue reactions than in those from patients with no reactions (51.0 +/- 17.7 and 29.6 +/- 10.1, respectively). A significant correlation was also found between the micronucleus frequency at 4 Gy and the severity of acute reactions and late reactions. However, the overlap between the micronucleus frequencies of patients with high-grade late normal tissue reactions and low-grade reactions is too great to recommend the micronucleus assay in its present form for routine clinical application.