Difference In Micronucleus Frequency Research Articles

Mutagenicity in oral cells of individuals exposed to radiofrequency generated by different smartphones

Aim: This study aimed to investigate whether non-ionizing radiation emitted by smartphones is likely to cause genotoxic effects on oral epithelial cells. Methods: Thirty adults were distributed into two groups according to the mobile phone brand used, namely Samsung (Samsung, Seoul, South Korea) and Apple (Apple, California, USA). The material was collected with gentle swabbing of the right and left buccal mucosa using a cervical brush, then the micronucleus test was performed. Results: The Mann-Whitney test with a 5% significance level did not reveal statistically significant differences in micronuclei frequency between the exposed and non-exposed sides (p=0.251). The different brands do not seem to cause risks of inducing genetic damage because there were no statistically significant differences between them (p=0.47). Conclusion: Therefore, our results suggest no correlations of micronuclei frequency in the exposed buccal cells of mobile phone users at the exposure standard levels observed.

Characterization of acute toxicity, genotoxicity, and oxidative stress of dimethoate in Rhinella arenarum larvae.

There is a great concern worldwide about the global decline of amphibians, particularly by agrochemical pollution. The aim of this study was to assess oxidative stress and genotoxicity of a commercial formulation of the insecticide dimethoate in Rhinella arenarum larvae, using sublethal biomarkers. The 24- and 96-h LC50 values of dimethoate to R. arenarum were 48.81 and 38.86 mg L-1, while the 96-h no observed effect concentration (NOEC) value was 20 mg L-1. For sublethal biomarker assays, R. arenarum larvae were exposed to 1.25, 2.5, and 5% of the 96-h NOEC (0.25, 0.5, and 1 mg L-1 dimethoate, respectively). After 96 h of exposure, inhibition of catalase (CAT) and glutathione S-transferase (GST) activities were registered. Also, an increased superoxide dismutase (SOD) activity was observed in larvae exposed to the highest concentration (1 mg L-1). Lipid peroxidation by increased thiobarbituric acid reactive substance levels in larvae exposed to 0.5 and 1 mg L-1 was detected. No differences in micronuclei frequency between treatments and negative control were observed. These results demonstrate the oxidative toxicity of dimethoate at sublethal concentrations in Rhinella arenarum larvae. The disruption of defense mechanisms may contribute to a deleterious impact on amphibian populations from habitats exposed to this organophosphorus insecticide.

Adaptation of the in vitro micronucleus assay for genotoxicity testing using 3D liver models supporting longer-term exposure durations.

Following advancements in the field of genotoxicology, it has become widely accepted that 3D models are not only more physiologically relevant but also have the capacity to elucidate more complex biological processes that standard 2D monocultures are unable to. Whilst 3D liver models have been developed to evaluate the short-term genotoxicity of chemicals, the aim of this study was to develop a 3D model that could be used with the regulatory accepted in vitro micronucleus (MN) following low-dose, longer-term (5 days) exposure to engineered nanomaterials (ENMs). A comparison study was carried out between advanced models generated from two commonly used liver cell lines, namely HepaRG and HepG2, in spheroid format. While both spheroid systems displayed good liver functionality and viability over 14 days, the HepaRG spheroids lacked the capacity to actively proliferate and, therefore, were considered unsuitable for use with the MN assay. This study further demonstrated the efficacy of the in vitro 3D HepG2 model to be used for short-term (24 h) exposures to genotoxic chemicals, aflatoxin B1 (AFB1) and methyl-methanesulfonate (MMS). The 3D HepG2 liver spheroids were shown to be more sensitive to DNA damage induced by AFB1 and MMS when compared to the HepG2 2D monoculture. This 3D model was further developed to allow for longer-term (5 day) ENM exposure. Four days after seeding, HepG2 spheroids were exposed to Zinc Oxide ENM (0–2 µg/ml) for 5 days and assessed using both the cytokinesis-block MN (CBMN) version of the MN assay and the mononuclear MN assay. Following a 5-day exposure, differences in MN frequency were observed between the CBMN and mononuclear MN assay, demonstrating that DNA damage induced within the first few cell cycles is distributed across the mononucleated cell population. Together, this study demonstrates the necessity to adapt the MN assay accordingly, to allow for the accurate assessment of genotoxicity following longer-term, low-dose ENM exposure.

The Impact of Mother's Living Environment Exposure on Genome Damage, Immunological Status, and Sex Hormone Levels in Newborns.

Background: The aim of this study was to compare for the first time IL-6 (Interleukin 6), testosterone (T) and estradiol (E) levels, their ratio (E/T), micronucleus (MN), and nuclear bridge (NB) frequency between newborns with regard to their mother’s residency and diet. Our results should enable an assessment of the possible environmental endocrine effects and interaction between biomarkers, pointing to possible associated health risks. Methods: Fifty full-term newborns of both sexes, whose mothers were healthy and not occupationally exposed to any known carcinogen, were analyzed. All of the mothers filled in a detailed questionnaire. Results: The results showed significantly higher levels of E in newborns of mothers with agricultural residency than those born by mothers with urban residency. Significantly, lower levels of E were measured in newborns of mothers who drank milk and carbonated beverages more frequently. Testosterone was significantly higher in boys of mothers with agricultural residency than from mothers with urban residency. Residence and other parameters had no impact on the difference in MN frequency. IL-6 levels were higher in newborns of mothers with agricultural residency. NB levels were significantly associated with E. A significant association between E levels and IL-6 was found. Conclusion: Our results were the first to show a significant impact of the mother’s agricultural residency and diet on their newborns’ sex hormone and IL-6 levels and their association.

GENOTOXICITY AND CYTOTOXICITY OF CBCT X-RAYS IN ORAL EXFOLIATED CELLS OF ADULTS

Background Cone beam computed tomography (CBCT) has become an important diagnostic tool in dentistry but has the disadvantage of exposing the patient to ionizing radiation, which may induce base damage, single- and double-strand breaks, and DNA protein crosslinks. Objective The aim of this study was to assess cytologic evidence of genotoxicity and cytotoxicity of x-rays in the oral exfoliated cells of adults subjected to partial and total (stitching module) CBCT by determining micronuclei frequency, associated with counting of degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis, buds, and broken eggs), and comparing partial and total (stitching module) CBCT in search of possible differences in the nature and/or intensity of the effects. Methods Thirty adults who were referred for total or partial CBCT were selected. Material collection was performed immediately before scanning and 10 days later, by scraping the vestibular mucosa with a plastic spatula. Statistical analysis was performed by using the paired t test for intragroup analysis and Student's t test for the intergroup data, with a significance level of 5%. Results No statistically significant difference was noted in the mean frequency of micronucleated cells before and after partial CBCT (P = .403). However, there was a significant difference in micronucleus frequency before and after total CBCT (P = .003). With regard to cytotoxicity, there was a statistically significant difference between partial and total acquisitions (P = .007 and P Discussion/Conclusions Only total CBCT seems to have a risk of inducing genetic damage, although both forms of CT scanning have promoted the induction of cytotoxic nuclear alterations.

The Response of Neotropical Fish Species (Brazil) on the Water Pollution: Metal Bioaccumulation and Genotoxicity.

The streams and rivers of the Upper Paraná River Basin have been seriously affected by impacts of high population density around the basin area. Fishes are widely used as models to assess the health of aquatic ecosystems, being considered as bioindicators of environmental pollution. In this context, our objective was to assess the potential genotoxic and mutageniceffects of the polluted water in three native fish species (Astyanax lacustris, Hypostomus ancistroides, and Rhamdia quelen) from Tarumã Microbasin, Upper Paraná River, Brazil. We also investigated the concentration of metals in water and in fish muscle to verify bioavailability and bioaccumulation of metals. For both less impacted sites (LI) and impacted sites (IMP) of the microbasin, the concentrations of metals were above the maximum limit allowed by Brazilian legislation (Resolution CONAMA 357/2005), except for Pb, total Cr, and Cu at LI sites and total Cr at IMP sites. A. lacustris showed a higher frequency of micronuclei (MN) at IMP sites compared with LI sites (p < 0.0001). We found no significant differences in MN frequency between site classes for H. ancistroides and R. quelen (p > 0.05). There were no significant differences between site classes regarding to nuclear abnormalities in erythrocytes frequencies (p > 0.05). A. lacustris from IMP sites had higher concentrations of Pb, Cu, Fe, Zn, and Ni in muscle tissue (p < 0.05), whereas H. ancistroides from IMP sites had higher concentration of Cr, Cu, and Ni (p < 0.0001) and R. quelen showed higher concentration of Cd, Fe, and Ni at these sites (p < 0.0001). So, the chosen biomarkers are able to identify the environmental risk of the water pollution.

Genotoxic effects on fish species and water quality parameters of two tributaries of the Sinos River, Southern Brazil

The integrated use of water quality parameters and the micronucleus test in fish represent a reliable tool in environmental assessment. Thus, this study aimed to evaluate water physicochemical and microbiological parameters and micronuclei (MN) and nuclear abnormalities (NA) frequencies in peripheral erythrocytes of three native fish species (Bryconamericus iheringii, Diapoma alburnus and Hyphessobrycon luetkenii) captured in the mouth of two tributaries (Ilha River and Paranhana River) of the Sinos River, Southern Brazil. Aluminium, iron and thermotolerant coliforms levels exceeded the limits established by the Brazilian legislation at both sampling sites. There were no differences in MN frequencies between sites and species; however, H. luetkenii presented higher rates of NA in comparison to D. alburnus captured in the Ilha River. Thus, this study provides the first in situ database of DNA damage for these fish species. Furthermore, water quality parameters indicate both sampling sites are under anthropic impacts.

Acute toxicity of commercial atrazine in Piaractus mesopotamicus: Histopathological, ultrastructural, molecular, and genotoxic evaluation.

Aim:The aim of this work was to evaluate the sensitivity of Pacu fingerlings (Piaractus mesopotamicus) by measuring the effects of median lethal concentration (LC50) of atrazine (ATZ - 28.58 mg/L) after acute exposure (up to 96 h).Materials and Methods:The fish were exposed to the LC50 of ATZ for 96 h (28.58 mg/L) in a static system. During the experiment, the fingerlings were randomly distributed in four glass tanks (50 L) containing dechlorinated water. Four glass tanks were for the control group, and four were for the ATZ-exposed group (n=4 per glass tank), given a total number of 16 animals tested per group. The genotoxicity was evaluated by micronucleus (MN) test in erythrocytes from peripheral blood. Qualitative and semi-quantitative histopathological analyses, and also ultrastructural study, were applied in liver and kidney samples. Finally, the content of heat shock protein (Hsp70) in the liver was evaluated by the western blotting method.Results:The morphological alterations in the liver, which was associated with increased expression of Hsp70, included nuclear and cytoplasmic vacuolization, cytoplasmic hyaline inclusions, and necrosis. The kidney presented edema and tubular cell degeneration with cytoplasmic hyaline inclusion. The semi-quantitative histopathological analyses indicated that the liver was more sensitive than kidney to ATZ-induced damage. Ultrastructural analysis showed that ATZ caused membrane alterations in several organelles and increased the number of lysosomes in hepatocytes and kidney proximal tubular cells. Nevertheless, no significant difference was observed in MN frequency in erythrocytes comparing treated and control groups.,Conclusion:These results indicated that ATZ-induced damage to the kidney and liver function, ATZ at the concentration tested did not induce a significant difference in MN frequency in Pacu erythrocytes comparing treated and control groups, and also that Pacu fingerlings may be a good bioindicator for testing freshwater contamination.

Evaluation of health effect among occupational population exposed to nano-titanium dioxide: a cross-sectional study

Objective: To characterize the health effects of nano-titanium dioxide exposure in an occupational cohort. Methods: Eighty-five male employees of a nano-titanium dioxide manufacturing enterprise in Shandong Province were evaluated in September 2014. Forty-four were exposed to nano-titanium dioxide (exposure group), and 41 were not exposed to nano-titanium dioxide (control group). We collected employees' basic information, smoking and drinking history, previous medical history, family history, and occupational history. Differences in blood pressure, hematological parameters, and blood biochemistry between the two groups were analyzed and compared. Multiple linear regression analysis was used to investigate the effect of nano-titanium dioxide exposure on blood pressure, hematological parameters, and blood biochemistry indices after controlling for age, smoking, drinking, and body mass index (BMI). Twenty-five employees from the exposure group and 25 employees from the control group were selected at random for measurement of genetic damage by cytokinesis-block micronucleus assay. Poisson regression analysis was used to investigate the effect of nano-titanium dioxide exposure on micronucleus frequency or micronucleus cell frequency after controlling for age, smoking, drinking, and BMI. Results: The median (P25-P75) surface area concentration of particles deposited in the tracheobronchial region, the surface area concentration of particles deposited in the alveolar region, and particle number concentration in the exposure group were 35.35(24.31-57.42) μ m2/cm3, 173.09(116.27-270.72) μ m2/cm3, and 40 244.00 (17 803.50-78 679.00) /cm3, respectively. These values were significantly higher than those in the control group 33.90 (27.44-43.29) μm2/cm3, 150.50(125.82-192.87)μm2/cm3, and 18 721.00 (12 721.00-51 898.50)/cm3, respectively. Z values were 15.47, 15.96, and 14.54, respectively (P<0.001 for all three values). Multiple linear regression analysis showed that exposure to nano-titanium dioxide contributed most to the alteration of mean corpuscular hemoglobin concentration, creatinine, and LDL-C, with standardized regression coefficients of 0.23, -0.51, and 0.30, respectively (P<0.05 for all three values), after adjusting for age, smoking, drinking, and BMI. There were no significant differences in micronucleus frequency and micronucleus cell frequency between the exposure group (3.00‰ (1.50‰-5.00‰) and 3.00‰ (2.00‰-4.00‰), respectively) and control group (2.00‰ (1.00‰-4.50‰) and 2.00‰ (1.00‰-4.00‰), respectively); P>0.05 for all comparisons. Poisson regression analysis showed that after adjusting for age, smoking, drinking, and BMI, there was still no statistically significant correlation between nano-titanium dioxide exposure and micronucleus frequency (OR=1.11, 95% CI: 0.81-1.54) or micronucleus cell frequency (OR=1.07, 95% CI: 0.75-1.51); P>0.05 for all comparisons. Conclusion: Nano-titanium dioxide particles exerted some health effects on the occupationally-exposed cohort, whose hematological parameters and blood biochemistry were influenced to some degree. However, a potential link between occupational exposure to nano-titanium dioxide and blood pressure or induction of genetic damage or was not found.

Delayed Numerical Chromosome Aberrations in Human Fibroblasts by Low Dose of Radiation.

Radiation-induced genomic instability refers to a type of damage transmitted over many generations following irradiation. This delayed impact of radiation exposure may pose a high risk to human health and increases concern over the dose limit of radiation exposure for both the public and radiation workers. Therefore, the development of additional biomarkers is still needed for the detection of delayed responses following low doses of radiation exposure. In this study, we examined the effect of X-irradiation on delayed induction of numerical chromosomal aberrations in normal human fibroblasts irradiated with 20, 50 and 100 cGy of X-rays using the micronucleus-centromere assay. Frequencies of centromere negative- and positive-micronuclei, and aneuploidy of chromosome 1 and 4 were analyzed in the surviving cells at 28, 88 and 240 h after X-irradiation. X-irradiation increased the frequency of micronuclei (MN) in a dose-dependent manner in the cells at all measured time-points, but no significant differences in MN frequency among cell passages were observed. Aneuploid frequency of chromosomes 1 and 4 increased with radiation doses, and a significantly higher frequency of aneuploidy was observed in the surviving cells analyzed at 240 h compared to 28 h. These results indicate that low-dose of X-irradiation can induce delayed aneuploidy of chromosomes 1 and 4 in normal fibroblasts.

Micronucleus frequency in exfoliated buccal cells from hairdresser who expose to hair products

Background: Hairdresser is one of the fastest growing occupations in today’s society. Hairdresser help styling, cutting, colouring, perming, curling, straightening hair and various treatment to customer. Somehow, hairdresser are constantly exposed to chemical substances such as aromatic amines, hydrogen peroxide, thioglycolic acid, formaldehyde in hair products which can cause damage to human’s genome. Micronucleus is one of the effective biomarker for processes associated with the induction of DNA damage. Purpose: The aim of this study was to determine the micronucleus frequencies in buccal mucosa epithelial cells of hairdresser who were exposed to chemical of hair products. Method: This study was conducted on twenty female subjects, who were divided into 2 groups: exposed and non-exposed (control) group. All subjects recruited were working in the same beauty salon. Buccal cells were obtained from each individual by using cytobrush. The cells were stained with modified Feulgen-Ronssenback method and counting of micronucleus per 1000 cell was done under light microscope. The data were analyzed using independent t-test and one-way Anova (p<0.05). Result: The result showed a significant difference in micronucleus frequency between 2 groups. There were a significantly increase of micronucleus frequency in hairdressers and increase of micronucleus frequency with the longer duration of exposure. Conclusion: It concluded that the chemical substances of hair products had affected the micronucleus frequency ofthe epithelial cells in buccal mucosa of hairdressers.

Cytogenetic Analysis among Train Depot Workers Exposed to Total Volatile Organic Compounds

Occupational exposure to toxic chemicals such as Total Volatile Organic Compounds (TVOC) from diesel engine exhaust implicates genotoxic risk. The objective of this study was to determine the DNA damage among KL Sentral depot workers exposed to TVOC by means of cytogenetic analysis. Data were obtained partially from disseminated questionnaires and buccal cells samples were collected from a total of 27 depot workers and 10 office workers by using wooden tongue depressor. TVOC measurement was carried out by using Photoionisation Detector (PID). 4 sampling points were selected, namely Locomotive (LOCO), Power Generating Car (PGC), refuelling of diesel and coach. Cytogenetic analysis was done by using Acridine Orange (AO) staining. Micronucleus (MN) frequency as a biomarker for DNA damage was scored from 1,000 cells per sample observed under fluorescence microscope. The results showed that the overall means of concentrations for TVOC were 0.1±0.1, 0.0±0.0, 0.1±0.0 and 0.1±0.0 in LOCO, PGC, refuelling of diesel and coach, respectively. TVOC concentration measured did not exceed the permissible level based on DOSH 2010. For the cytogenetic analysis, depot workers showed significantly higher MN (p<0.001) than the office workers. Besides that, the sociodemographic factors (e.g., age, smoking status) and the MN frequency of the depot workers were also significantly higher than the office workers. However, there was no significant difference in MN frequency between workers wearing Personal Protective Equipment (PPE) and without wearing PPE [MN (p=0.491)]. In addition, there was a positive correlation between the working period (year) and the frequency of MN with r2=0.54, p<0.01. The result also showed that exposure to TVOC was a significant predictor of the MN frequency (p<0.001). On the other hand, smoking status did not show any significant association with the frequency of MN. These findings showed that depot workers exposed to TVOC were prone to DNA damage. Therefore, biomonitoring of DNA damage among depot workers is recommended in order to improve occupational health and safety condition in their workplace.

Differences in micronucleus frequency and acrylamide adduct levels with hemoglobin between vegetarians and non-vegetarians.

Nutrients and food constituents can prevent or contribute to genotoxicity. In this study, the possible influence of a vegetarian/non-vegetarian diet on genotoxic effects was investigated in 58 non-smoking healthy vegetarians (V) and non-vegetarians (NV), age 21-37 years from the Stockholm area in Sweden. Physical activity and dietary habits were similar in both groups, with the exception of the intake of meat and fish. Using flow cytometry, we determined the formation of micronuclei (MN) in transferrin-positive immature peripheral blood reticulocytes (Trf-Ret) (Total: n = 53; V: n = 27; NV: n = 26). Dietary exposure to acrylamide was measured through hemoglobin (Hb) adducts in peripheral erythrocytes (Total: n = 53; V: n = 29; NV: n = 24). Hb adducts of both acrylamide and its genotoxic metabolite glycidamide were monitored as a measure of the corresponding in vivo doses. Our data demonstrated that compared with the non-vegetarians, the vegetarians exhibited lower frequencies of MN (fMN) in the Trf-Ret (p < 0.01, Student's t test). A multivariate analysis demonstrated that there was no association between the fMN and factors such as age, sex, intake of vitamins/minerals, serum folic acid and vitamin B12 levels, physical activity, and body mass index. The mean Hb adduct levels of acrylamide and glycidamide showed no significant differences between vegetarians and non-vegetarians. Furthermore, there were no significant relationships between the adduct levels and fMN in the individuals. The ratio of the Hb adduct levels from glycidamide and acrylamide, however, showed a significant difference (p < 0.04) between the two groups. These data suggest that the vegetarian diet might be beneficial in lowering genomic instability in healthy individuals. The measured Hb adduct levels indicate that the total intake of acrylamide does not differ between the two studied groups and does not contribute to the observed difference in fMN, although an influence of the diet on the metabolic rates of acrylamide was indicated. In addition, the observed significant difference in the background fMN in the two groups demonstrated that the MN analysis method has a sensitivity applicable to the biomonitoring of human lifestyle factors.

Increased frequency of micronuclei in binucleated lymphocytes among occupationally pesticide-exposed populations: a meta- analysis.

The cytokinesis-block micronucleus (CBMN) assay is a standard cytogenetic tool employed to evaluate chromosomal damage subsequent to pesticide exposure. To evaluate the pooled levels of total micronuclei (MN) and binucleated cells with micronuclei (MNC) in 1000 binucleated lymphocytes among population occupationally exposed to pesticides and further determine the more sensitive biomarker of CBMN. A meta-analysis on the pooled levels of MN and MNC in binucleated lymphocytes among occupationally pesticide-exposed populations was conducted using STATA 10.0 software and Review Manager 5.0.24 in this study. We found significant differences in frequencies of MN and MNC in 1000 binucleated lymphocytes between pesticide-exposed groups and controls, and the summary estimates of weighted mean difference were 6.82 [95% confidence interval (95% CI): 4.86-8.78] and 5.08 (95% CI: 2.93-7.23), respectively. However, when we conducted sensitivity analyses further, only the MN remained statistically different, but not the MNC, the summary estimates of weight mean difference were 2.86 (95% CI: 2.51-3.21) and 0.50 (95% CI: -0.16-1.17), respectively. We also observed pesticide-exposed subjects had significantly higher MN frequencies than controls among smokers and nonsmokers, male and female populations, and American, Asian and European countries in stratified analyses. The frequency of MN in peripheral blood lymphocytes might be a more sensitive indicator of early genetic effects than MNC using the CBMN assay for occupationally pesticide- exposed populations.

Role of the CYP1A2 Gene Polymorphism on Early Ageing from Occupational Exposure.

The ageing process is influenced by many internal and external factors. The toxic substances in the environment can cause genomic damages to cells, which increase the risk of early ageing. Furthermore, the cytochrome P450 1A2 (CYP1A2) gene polymorphism is a susceptibility factor and may enhance the risk of DNA damage in cells. The current study was carried out to show whether occupational exposure could cause genotoxicity in cells carrying the CYP1A2 gene polymorphism, thus enhancing the likelihood of early ageing. This study was conducted on mechanical workshop workers and a control group by collecting buccal cells from their mouths. Restriction fragment length polymorphism-polymerase chain reaction (RFLP-PCR) was used to identify the CYP1A2 gene polymorphism in the cells. In addition, three extra methods including micronuclei (MN) test, comet assay and real-time PCR (RT-PCR) were applied to determine the effects of gene polymorphisms on DNA damage and ageing from occupational exposure. The results showed that DNA damage in the cells carrying the mutated genotype was higher than the wild genotype. In addition, the difference in MN frequency (p = 0.001) and relative telomere length (p = 0.002) between workers and controls was significant (p <0.05) in the mutated genotype. The findings indicated a possible protective effect of gene polymorphism against early ageing, which was characterized by lack of a significant influence of CYP1A2 gene polymorphism on genetic material in the subjects (p >0.05). It was concluded that the CYP1A2 gene could be a contributing factor to prevent early ageing from occupational exposure.

Nuclear abnormalities in erythrocytes and morphometric indexes in the catfish Cathorops spixii (Ariidae) from different sites on the southeastern Brazilian coast

Nuclear abnormalities in erythrocytes (NAE) were taken as biomarkers in the catfish Cathorops spixii (Ariidae) sampled in an estuary little affected by human activity (Cananéia) and in three regions (Santos Channel: SC, Santos Bay: SB and São Vicente Channel: SVC) of the Santos-São Vicente estuary impacted by various anthropogenic activities. Increases in NAE were observed in fish from SC and SVC sampled in the summer period as compared with specimens from the Cananéia estuary. These results suggest the presence of genotoxic compounds in these regions. However, the absence of significant differences in micronuclei frequency reflects slight mutagenic effects in these individuals. It is possible that the lower NAE frequency in specimens from SB might be associated with the greater remobilization and dilution of chemicals in this region. The low frequency of NAE in C. spixii from the Cananéia estuary is in accordance with the slight anthropogenic influence in this system, and may be suggestive of the absence of genotoxic and mutagenic effects in these organisms.

Role of micronucleus test in predicting breast cancer susceptibility: a systematic review and meta-analysis

Background:The cytokinesis-block micronucleus test (MNT), as a marker of chromosomal mutagen sensitivity, was applied in a number of studies enrolling breast cancer (BC) patients and subjects with known or putative genetic predisposition to BC. The large majority of them involve the evaluation of induced micronuclei (MN) frequency in peripheral lymphocytes, after the in vitro challenge with ionising radiations.Methods:The aim of the present systematic review and meta-analysis is to investigate the role of MN assay in the identification of individuals at increased risk of BC and its potential use as prescreening test in women with a family history (FH) of BC.Results:Twelve studies were included in the meta-analysis, covering a time interval 1998–2007, and including 752 cases and 593 controls. Among the cases, 629 are cancer patients and 123 are cancer-free subjects, including 32 first-degree relatives of the susceptible subjects and 91 BRCA1/2 mutation carriers. Our meta-analysis reveals a significant increase of baseline MN frequency related to cancer status, but the association with FH of BC and specifically with BRCA mutations is not clear. A larger difference in MN frequency between cases and controls was observed after in vitro challenge, but response to radiation exposure doesn't appear to better discriminate cancer-susceptible subjects.Conclusion:Our study suggests the presence of some bias affecting many of these studies, reinforcing the suggestion that a more rigorous study design is needed in this area.

Evaluation of genotoxicity induced by exposure to antineoplastic drugs in lymphocytes of oncology nurses and pharmacists

The hazards of handling antineoplastic drugs have been raised and discussed in several studies. Introduction of new antineoplastics together with abuse of safety standards have contributed to the exposure risk for personnel who handle these substances. Interactions of antineoplastic drugs with biological structures vary according to the drug(s) and the individual's genetic susceptibility. This study was carried out to evaluate the genome damage induced by exposure to antineoplastic drugs in nurses (n = 20) and pharmacists (n = 18) working in the Oncology Department of Tanta Cancer Center. Thirty subjects matched in age, gender and smoking habit were selected as controls. Both chromosomal aberration analysis and micronucleus assay were used to evaluate genome damage in peripheral blood lymphocytes of the study subjects. The numbers of aberrant lymphocytes, as well as chromosomal aberration and micronuclei frequencies, were significantly increased in exposed personnel in comparison to matched controls. Compared with pharmacists, nurses showed notably higher level of chromosome damage. On the other hand, no significant difference in micronuclei frequency was observed between nurses and pharmacists. Correlation analyses pointed to the influence of age and duration of occupational exposure on the level of chromosome damage among exposed subjects. The results of this study confirmed that handling antineoplastic drugs without appropriate precautions imposed a genotoxic risk for exposed healthcare workers. These results address the need for regular biomonitoring of exposed personnel. In addition, they call attention to the need for proper implementation of intervention measures aiming to eliminate or significantly reduce worker exposure and prevent untoward biological effects.

Micronuclei assay: A potential biomonitoring protocol in occupational exposure studies

As micronuclei (MN) derive from chromosomal fragments and whole chromosomes lagging behind in anaphase, the MN assay can be used to show both clastogenic and aneugenic effects. This particularly concerns the use of MN as a biomarker ofgenotoxic exposure and effects, where differences in MN frequencies between exposed subjects and referents are expected to be small. The present paper reviews the use of the MN assay in biomonitoring of occupational exposure studies.

Cervical precancerous lesions – chromosomal instability in peripheral blood lymphocytes in relation to lesion stage, age and smoking habits

To evaluate chromosomal damage in peripheral blood lymphocytes (PBL) of patients newly diagnosed with cervical precancerous lesions with respect to age, smoking habits, miscarriages, abortions and lesion stage. Clinical study. Clinic of Gynecology and Obstetrics in Kragujevac, Serbia, during 2009-2010. The analyzed samples included 41 untreated patients aged 24-65 years with a diagnosed low-grade squamous intraepithelial lesion (LSIL; 19 patients) or a high-grade squamous intraepithelial lesion (HSIL; 22 patients). Control samples were obtained from 40 healthy women aged 24-53 years. The frequency of micronuclei (MN) was estimated in circulating lymphocytes by using the cytokinesis-block micronucleus assay. The frequency of MN in PBL. The mean MN frequencies of both LSIL and HSIL patients were significantly higher than the MN frequency of healthy control women. There was no significant difference in MN frequency between LSIL and HSIL patients, between smokers and nonsmokers in both patient and control samples, or between miscarriage groups and abortion groups of patients. Considering confounder factors, age and health status influenced MN frequency. The results suggest that MN frequency in PBL of patients with cervical precancerous lesions corresponds to an increase of chromosomal damage, irrespective of smoking habits, miscarriages, abortions and lesion stages.