Micronucleus Count Research Articles

Micronuclei in the exfoliated oral epithelial cell: a cross-sectional study in Peruvian artisanal miners

Introduction: Artisanal mining in Peru is an activity that generates a risk of exposure to different compounds, among which mercury and particulate matter stand out. The use of laboratory indicators to assess genotoxicity induced by work activity is a priority need. Our objective was to determine the micronucleus count in buccal cells of artisanal miners in Peru during 2020. Methods: We designed a cross-sectional study where 80 artisanal miners were evaluated who underwent scraping in the inner area of the cheek to obtain epithelial cells that were stained with Feulgen's staining, and micronuclei and nuclear alterations were identified on a count of 2000 cells. Results: We found that the mean micronucleus count was 27.5±8.0 (CI95: 25.7 – 29.3, min. 15, max. 48). For the other nuclear alterations such as nucleoplasmic bridges, budding, and binucleation, only up to one alteration was evidenced for each total count. The number of years of work (p=0.004) and age (p<0.001) were the only variables associated with the micronucleus count. Conclusion: The nuclear alterations in buccal cells of artisanal miners exposed to particulate material were micronuclei, nucleoplasmic bridges, budding, and binucleations, the most frequent being the presence of micronuclei, with a mean value of 27.5 micronuclei per 2000 cells counted.

The adverse effects of mining pollutants on oral mucosa in Bellary district: A clinical and genotoxicity study.

The Bellary district in Karnataka, rich in mineral resources, is a major mining industry, but prolonged exposure to mining can lead to health hazards. The study aims to assess the genotoxic impact of mining pollutants on mine workers using the micro-nucleus (MN) assay. Cross-sectional study. A total of 250 individuals (198 males and 52 females) working in mining areas were examined, and their oral findings were recorded in a proforma. For the micro-nucleus assay, buccal smears from 30 individuals working in mining areas with habits, 30 individuals working in mining areas without habits, and 30 individuals residing in non-mining areas (control group) were selected. Smears were stained with Giemsa stain to identity and quantify the MNs. The frequency of oral mucosal problems among 250 persons working in mining regions was 170 (68.0%) with no oral mucosal conditions, 79 (32.6%) with oral mucosal conditions, 25 (10%) with leukoplakia, 1 (0.4%) with lichen planus, and 8 (3.2%) with ulcerations. Acute necrotising gingivitis was reported in one person (0.4%), candidiasis in two (0.8%), abscess in two (0.8%), OSMF in 39 (15.6%), and oral cancer in two (0.8%). The mean MN count was 2.40 + 1.57 in mine employees with habits, 2.18 + 1.25 in mine workers without habits, and 1.40 + 0.55 in normal healthy controls. Reduced occupational health risks brought on by exposure to mining contaminants require protective measures. After being exposed to mining pollutants, exfoliated buccal mucosal cells can be examined for genotoxicity.

POST-SIEGE GENOTOXIC HAZARDS IN LAKE LANAO, PHILIPPINES BY MICRONUCLEUS ASSAY

Massive war pollutants brought by Marawi Siege in the Philippines have contaminated the city environs and the surrounding ancient Lake Lanao. Munition residues including heavy metals are reportedly genotoxic hence this study was conducted to determine the post-siege genotoxic hazards posed by the munition pollutants through micronucleus (MN) assay on the slow-moving edible gastropod snails Vivipara angularis Muller (locally known as “suso”) thriving in the lake. MN, a biomarker of genotoxicity was examined and counted in the hemocytes of exposed juvenile and adult snails. Results revealed that MN frequencies (no. of MN/1000 hemocytes) were significantly higher in snails sampled in Lake Lanao lakeshores than in the reference site Lake Dapao. Among adult samples, there was a decreasing trend of MN frequencies with increasing distance from lakeshore fronting warzone ‘ground zero’ where the battle was heaviest (site A) to sampling sites away from it: sites B, C, and D (Lake Dapao) which are 8.15 km, 24.41 km, and 34.45 km, respectively. Moreover, varied patterns of micronucleation were observed between age groups and sites, i.e., in all sites except C, adults had greater MN counts than juveniles which were significant in site A only. Unexpectedly juveniles displayed significantly high MN counts than adults in site C. The elevated MN frequencies in the snail hemocytes exposed to war pollution could be attributed to genotoxic munition residues eroded and washed into the lake water. Moreover, heavy metals which are common components of weaponries were also detected in the snail muscles, although at concentrations within safe levels but continued consumption may be cautioned to avoid biomagnification. Other genotoxins must be present in site C other than munition residues predisposing the juvenile snails. The results are baseline data on the MN frequencies in V. angularis exposed to war pollutants in Lake Lanao which need further investigation. Post-siege genotoxic hazards in the lake by MN assay cannot be ignored, thus local leaders must be informed of the results for possible intervention to protect the health and well-being of the community. 
 

L-glutamic acid-g-poly hydroxyethyl methacrylate nanoparticles: acute and sub-acute toxicity and biodistribution potential in mice.

The aim of this safety study in mice was to determine in vivo toxicity and biodistribution potential of a single and multiple doses of L-glutamic acid-g-p(HEMA) polymeric nanoparticles as a drug delivery system. The single dose did not cause any lethal effect, and its acute oral LD50 was >2.000 mg/kg body weight (bw). Multiple doses (25, 50, or 100 mg/kg bw) given over 28 days resulted in no significant differences in body and relative organ weights compared to control. These results are supported by biochemical and histological findings. Moreover, nanoparticle exposure did not result in statistically significant differences in micronucleus counts in bone marrow cells compared to control. Nanoparticle distribution was time-dependent, and they reached the organs and even bone marrow by hour 6, as established by ex vivo imaging with the IVIS® spectrum imaging system. In conclusion, L-glutamic acid-g-p(HEMA) polymeric nanoparticles appear biocompatible and have a potential use as a drug delivery system.

Study of liver toxicity and DNA damage due to exposure to the pesticide Mancozeb in an experimental animal model - A pilot model.

Mancozeb is one of the most widely used Ethylenebisdithiocarbamates fungicides in Brazil. A pilot experimental model was created to evaluate its potential hepatotoxic effect. An experimental study was performed with 27 male Wistar rats (3 groups). The Control Group received a saline solution, while Intervention Groups I and II received 250 mg/kg and 500 mg/kg of Mancozeb respectively, once a week, for 12 weeks. Anthropometric measurements were carried out, and the marker of biological exposure in urine was dosed. Biochemical tests, evaluation micronucleus count, comet and oxidative stress markers assay, and histological assessment of the liver were also performed. The hepatotoxic effect of Mancozeb was confirmed by anthropometric measurements, genotoxicity, and oxidative stress. Statistically significant results were found when the exposed groups were compared to the control group. These results were supported by inflammatory infiltration and balloonization in the treated groups. The experimental model effectively demonstrated the deleterious effect of Mancozeb on the liver.

EVALUATION OF CYTOGENIC DAMAGE IN ORAL EXFOLIATED BUCCAL CELLS OF TOBACCO USERS AND PATIENTS WITH POTENTIALLY MALIGNANT DISORDERS USING MICRONUCLEUS ASSAY - A PROSPECTIVE STUDY

Background: Cytogenic methods acts with complex type mutations, known as structural mutations (aberrations)and a special type of chromosomal damage, known as micronucleus. So, micronucleus (MN) assay has been used as a biomarker of genetic damage in buccal mucosa cells. Aim and Objectives: To evaluate micronucleus in the exfoliated cells of buccal mucosa of individuals with potentially malignant disorders and different tobacco related habits and in control group. To observe the incidence of micronucleus count based on duration, frequency and type of tobacco usage and also auto immune condition of Lichen planus. Materials and Method: The study population is divided into 3 groups. Group I : 15 healthy subjects (control), Group II : 15 smokers or chewers with habits andno evidence of lesion Group III : 30 Patients clinically diagnosed as having PMD of the oral cavity. Smears stained with DNA specific Feulgen stain. Association of micronucleus between all groups and its mean and standard deviation was assessed with ANOVA with p<0.05 was considered as significant level. Results: The mean MN revealed that individuals with potentially malignant disorders had 26.8±5.1, individuals with tobacco habit (smokers/chewers) had 11.0±5.5 and controls had 0.2±0.5. The ANOVA test for association and mean frequency of micronucleus between all groups revealed significant value of <0.001. Conclusion: Hence, MN assay in oral exfoliated buccal cells can be conveniently used as a biomarker for screening of potentially malignant disorders of oral cavity. And also provides an insight into the importance of early detection and prevention of OPMDs.

Liver toxicity and DNA damage from exposure to the pesticide Mancozeb

Introduction: Brazilian agriculture has developed to such an extent in the last 40 years that the country will become one of the world’s largest food suppliers in the future. Indeed, to keep up this production, agriculture makes intensive use of fertilizers and agricultural pesticides, helping Brazil become one of the main pesticide consumers worldwide. Ethylenebisdithiocarbamates are a group of fungicides that have been widely utilized around the world, and Mancozeb is one of their main representatives. Therefore, a pilot experimental model was created to evaluate the potential hepatotoxic effect of Mancozeb. Materials and Methods: An experimental study was performed with 27 male Wistar rats, divided into 3 groups of 9 rats. Control Group received saline solution, Intervention Group I received 250 mg/kg once a week and Intervention Group II received 500 mg/kg also once a week. The treatment was performed for 12 weeks. Anthropometric measurements were performed and the marker of biological exposure in urine was dosed, biochemical tests, evaluation micronucleus count and comet assay, oxidative stress markers and histological assessment of the liver were done. Results: The hepatotoxic effect of exposure to Mancozeb was confirmed by different tests: anthropometric measures, genotoxicity, and oxidative stress. Statistical significance was found when exposed groups were compared to the control. These results were supported by microscopic evaluation of the liver tissue, where histological changes were found such as inflammatory infiltrate and balloonization in the treated groups. Conclusion: Experimental model was effective to demonstrate the deleterious effect on the liver due to exposure to Mancozeb.

Genotoxicity of PM2.5 and PM1.0 Particulates on Human Peripheral Blood Lymphocytes in Manila, Philippines

Urban air quality is increasingly being studied as a fraction of the world’s population is living in megacities. In this study, particulate matter (PM) along Taft Avenue, Manila, the Philippines, is investigated in terms of its ability to induce genetic damage in human peripheral blood lymphocytes (PBLs). Size-segregated roadside air samples were obtained from 2015–2017 near a university gate and analyzed using in vitro micronucleus (MN) and cytokinesis-block proliferation tests. While cellular proliferation was unaffected by 0–0.1 kg/m3 of PM1.0 and PM2.5, PBL cells treated with PM2.5 displayed a significantly higher micronucleus count (p = 0.03) compared to the cells treated with PM1.0. Atomic absorption spectroscopy revealed greater amounts of Cd, Ca, Pb, K, Na, and Zn in PM2.5 compared to PM1.0. The results indicate that the differences in composition of the two size fractions of air particulates are associated with their genotoxicities.

Influence of smoking on oral cells genotoxicity after at-home bleaching using 22% carbamide peroxide: a cohort study.

ObjectiveThis study evaluated the influence of smoking on the oral cells genotoxicity before and after at-home bleaching using 22% carbamide peroxide (CP).Materials and methodsThis is a prospective observational analytics cohort study which evaluated nonsmokers (NS; n = 24) and smokers (S; n = 16) patients. At-home bleaching was performed using 22% CP gel in individual trays for 1 h per day for 14 days in both groups. Scrapped cells from marginal gums were collected before the bleaching treatment (D0-baseline) and 1 day (D1), 15 days (D15), and 1 month (D30) after its finishing. Cells were stained with Giemsa 10%, and the micronucleus (MN) and metanuclear alterations (MA) were counted by a trained operator in 1000 cells per patient. The collections and data analysis occurred blindly. Data was analyzed by Kruskal–Wallis, Dunn, and Mann–Whitney test (α = 0.05).ResultsMN frequency was not influenced by smoking or bleaching. An increase of MA was observed between D0 and D30 for both groups (p < 0.001); however, no statistical difference was found between NS and S (p > 0.05) in the evaluation times.ConclusionSmoking associated with 22% carbamide peroxide gel for at-home bleaching does not show genotoxic potential analyzed by the MN counts. However, a significant increase of MA was found for smokers and nonsmokers.Clinical relevanceDespite of the increase in MA, smoking associated with 22% CP peroxide at-home bleaching showed no important genotoxic potential (MN) for oral cells. Therefore, at-home bleaching treatment is safe for nonsmokers and smokers even with a high carbamide peroxide concentration of 22%.

A Study on Micronuclei in Tobacco and Related Habits

Introduction: Oral cancer is one of the ten most common causes of mortality in developing countries like India. A micronucleus (MN) is a small extra nucleus separated from the main one, generated during cellular division by late chromosomes or by chromosome fragments. Micronucleus is a potential biomarker for malignancy. Aim and Objectives: The study attempts to analyze micronuclei in buccal smear from patients with tobacco and related habits; and to determine its reliability as a biomarker for carcinogenesis. Study Design: A total of 400 consisting of normal subjects, patients with potentially malignant lesions and patients with malignant lesions were included in the study. Oral exfoliated cells were collected by scrapings of buccal mucosa of both control and study groups with a tooth brush. The scrapings collected from right and left buccal mucosa of each subject were studied under two separate slides. A total of 500 cells were examined from each slide. All the micronucleus cells located on each slide were examined again under the 100X magnification. Results: The P value for intergroup difference in average number of micronuclei in cells of buccal mucosa among all groups was &lt;0.001 which was highly significant. The P value for micronucleated cells of buccal mucosa among all groups was &lt;0.001 which was highly significant. Conclusion: A stepwise increase in MN counts from normal to potentially malignant to carcinoma suggested a link of this biomarker with neoplastic progression. Micronuclei can be used as a biomarker for early detection of premalignant and malignant lesions of the oral cavity.

The biocompatibility of Achyrocline satureioides plant extract over human gingival fibroblasts

Objective: Achyrocline satureioides “A.satureioides” is a subshrub, widely distributed in South America because of its medicinal properties. Although it is widely used in folk medicine, there is still no approval for its therapeutic use, and its biocompatibility is little explored. This study aimed to evaluate its cytotoxicity and genotoxicity over human gingival fibroblasts (FMM-1). Methodology: Ten different concentration of the glycolic extract of A.satureioides were tested for 5min and 24h of contact with the cells to evaluate its cytotoxicity using the MTT colorimetric assay and to evaluate its genotoxicity using the micronucleus assay. Data were analyzed with one-way ANOVA and Tukey test with a significance level (α=0.05). Results: All tested concentrations of the extract presented cell viability more than 70% and has no significant difference of the control group after 5min and 24h. However, for 5min the 100 mg/mL was cytotoxic and for 24h the 1.56 mg/mL stimulated cell proliferation. For genotoxicity analysis, only the concentration 6.25 mg/mL showed results similar to the control of cell culture in the micronucleus count after 5min and 24h. Conclusions: The glycolic extract of A.satureioides doesn’t have cytotoxic and genotoxic effects in concentrations up to 6.25 mg/mL, but in high concentrations it is considered genotoxic.

Micronucleus assay in formalin exposed individuals

Introduction: The aim of the study was to find out the nuclear abnormalities like Micronuclei in the oral mucosa of the formalin exposed individuals in the department of anatomy. This MN Aaasy is an inexpensive method. Materials and Methods: Faculties and staffs working in the department of anatomy and the first-year students were included in this study. Study sample consists of 50 subjects and was divided into 5 groups according the years of exposure. By scraping with the wooden spatula in the buccal mucosa Oral squamous cells were collected and smeared on the slides. The smeared slides were fixed with methanol glutaraldehyde fixative and stained with giemsa, maygrunwald stain. After airdrying 1000 cells were screened for Micronucleus (MN). Results: Micronuclei frequency was more in the group who had more than 15 years of formalin exposure. The mean MN count was 9.60 and it was statistically significant when compared to other groups. Conclusion: Micronucleus Assay is the most simple, feasible, inexpensive method to find out the nuclear abnormalities at an early stage in the formalin exposed individuals. Keywords: Formalin, Buccal Mucosa, Micronucleus.

English

Stress, excessive consumption of processed foods, pollutants and many other factors of today&#39;s life have caused oxidative stress in our body and damage to genetic material in our cells, leading to diseases such as diabetes, hypertension, cancer, metabolic syndrome, among others. Medicine has returned to take up traditional remedies mainly in plants. Chaya (Cnidoscolus aconitifolius) has been studied in this regard, mainly for its antidiabetic effects; however, there is little information about its antioxidant and protective properties against genotoxic damage. The present study focuses on the evaluation of the antioxidant and protective properties to genotoxic damage of aqueous and methanolic extracts of chaya leaves (C. chayamansa) in a model in mice which were induced to oxidative stress and genotoxic damage by exposure to arsenic and low doses of streptozotocin. Genotoxic damage was assessed by micronucleus count and antioxidant properties were assessed in the extracts and plasmas of the mice by the ABTS radical and using Trolox as standard. Additionally, the extracts were analyzed by HPLC-MS/MS. Mice treated with aqueous extract showed better recovery than those treated with methanolic extract; however, no significant statistical differences were found between both groups. HPLC analysis suggests the presence of some compounds of interest such as ferulic acid, protocatechonic acid, riboflavin, kaempferol and beta carotene. These could be associated with the effects of protection against genotoxic damage and as antioxidants found in the study. The aqueous extract seems have the best performance against genotoxic damage and have better oxidative properties, so the consumption of chaya can be recommended. Key words: Cnidoscolus aconitifolius, Chaya, genotoxic damage, oxidative stress, micronucleus, High Performance Liquid Chromatography (HPLC). &nbsp

In vivo study on the toxic, cytotoxic, and genotoxic potentials of stem bark ethanolic extract of Cenostigma gardnerianum Tul. (Caneleiro)

Many species of medicinal plants have been used as a therapeutic alternative in the treatment of diseases around the world, as well as promoting advances in the production of herbal medicines. However, this use is often done indiscriminately and leads to serious consequences in the body of those who use them. Therefore, studies on the toxic, cytotoxic, and genotoxic potentials of medicinal plant species are necessary for their safe use. Cenostigma gardnerianum Tul, popularly known as Caneleiro or Canela-de-velho, is widely used by the population for its anti-inflammatory, antispassmolytic, antitussive, antifungal properties, among others. The aim of this research was to study and analyze a possible toxicity, cytotoxicity, and genotoxicity of the ethanolic extract from the bark of the stem of Cenostigma gardnerianum Tul. by means of the Allium cepa in vivo bioassay. The extract was divided into four concentrations, divided into groups A, B, C and D, respectively: 0.5mg/ml, 1.0mg/ml, 2.0mg/ml and 5.0mg/ml, in addition to the Negative Control (dechlorinated water), Positive Control (dimethyl sulfoxide) and Blank control (distilled water). The roots were measured for toxicity evaluation, the Mitotic Index (MI) was calculated for cytotoxicity research, and finally micronuclei count was performed to study the genotoxicity of each extract concentration. The low growth of the meristems indicated the presence of toxicity; the mitotic indices found were statistically lower than in the negative control, revealing cytotoxicity; and the high micronucleus count showed the presence of genotoxicity. From the results obtained, it was concluded that the ethanolic extract of the Caneleiro bark presents toxic, cytotoxic, and genotoxic activity, with statistically significant values for concentrations starting from 2mg/ml.

Quantitative analysis of the efficacy of Papanicolaou, acridine orange, and AgNOR in oral exfoliative smears smokers for detecting micronuclei – A cross-sectional comparative study

Context: Dentistry and its associated specialties play a crucial role in diagnosing and treating oral diseases due to deleterious oral habits. Oral health-care providers also conduct researches to identify the association between oral diseases resulting from these bad oral habits, such as oral squamous cell carcinoma. Aim: The purpose of this quantitative cross-sectional study was to compare the efficacy of exfoliative Papanicolaou staining (PAP) stains, acridine orange (AO), and AgNOR for detecting micronucleus (MN) count in smokers' (individuals with the habit of smoking) oral mucosa. Materials and Methods: Exfoliative cytology smears obtained from thirty smokers' oral mucosa were divided into three equal groups to evaluate the frequency of MN count after staining with PAP, AO, and AgNOR. Smears were collected from smokers' oral mucosa ranging in age from 30 to 70 years who visited the Department of Oral Medicine and Radiology and from the Department of Oral Pathology and Microbiology. Results and Stats: This research revealed the slightly different and higher MN count in PAP stain in the mean count among all the three stains after analysis and evaluation along with considerably higher in AO stain compare to AgNOR stain. Data were analyzed using Statistical Package for the Social Sciences SPSS software (windows Version 22.0 Chicago, IL, USA). Conclusion: In this quantitative, cross-sectional study, with limitations and pitfalls, the results showed higher proliferative activity in smokers' oral mucosa without any oral lesions and higher mean MN count in PAP stain followed by a mean range of AO stains.

Evidence of genotoxicity and cytotoxicity of X-rays in the oral mucosa epithelium of adults subjected to cone beam computed tomography.

Evidence of genotoxicity and cytotoxicity of X-rays in the oral mucosa epithelium of adults subjected to cone beam computed tomography.

Micronucleus count in nasal epithelial cells from patients with chronic rhinosinusitis and polyps

IntroductionChronic rhinosinusitis with nasal polyps, a prevalent disease affecting around 2% of the world population, is characterized by symptomatic inflammation of the nasal mucosa and impairment of quality of life. Chronic rhinosinusitis with nasal polyps has a multifactorial etiology, involving a dysfunctional host response to environmental factors. Thus, inflammatory models may be useful to shed light on the pathophysiology of this disease. Micronucleus count has been used to screen DNA damage in various tissues. ObjectiveTo investigate the association between frequency of micronucleus in exfoliated cells from the nasal cavity of patients with chronic rhinosinusitis with nasal polyps and disease severity. MethodsThis cross-sectional study included 21 patients with chronic rhinosinusitis with nasal polyps and 19 controls without disease. None of the participants were smokers. ResultsMean micronucleus count was 3.690 per 1000 cells (±2.165) in individuals with vs. 1.237 per 1000 cells (±0.806) in controls; (Student's t test = 4.653, p < 0.001). Nasal surgery in the past 5 years and aspirin-exacerbated respiratory disease were not associated with nicronucleus count (p = 0.251). ConclusionMicronucleus count seems to be linked to chronic rhinosinusitis with nasal polyps, providing a new perspective for the evaluation of this disorder.

A Comparative Study for Selectivity of Micronuclei in Cervical Exfoliated Cells on Chronic Boron Effects.

Background:Cervical cancer is one of the most frequent malignancies in women. Micronucleus (MN) testing has gained popularity as a biomarker in early diagnosis of many types of cancer.Aims:This study aims to investigate the role of MN testing on early detection of cervical cancer and the effect of boron exposure on cervical cells.Settings and Design:The study population comprised women who were diagnosed to be human papillomavirus (HPV)-positive and had atypical squamous cells of undetermined significance (ASCUS) as cervical cytology in a cervical screening project. A total of 15 HPV-positive and 36 ASCUS patients were identified. Randomly selected 20 women were selected from boron-rich region (n = 10) and nonboron region (n = 10).Materials and Methods:Cervical swab specimens were dyed using Papanicolaou (PAP) and May–Grünwalds–Giemsa (MGG) techniques, and MN count in 1000 cells was performed. The results were statistically evaluated.Statistical Analysis Used:Data were analyzed using Statistical Package for the Social Sciences (SPSS) version 13. Quantitative data were presented as mean ± standard deviation. MN test scoring was compared using Mann–Whitney U-test.Results:Boron content of urine was measured to be 3.02 ± 1.45 and 0.98 ± 0.42 mg/day in boron-rich and nonboron regions, respectively. When MN counts were compared according to PAP and MGG staining in HPV- and ASCUS-positive women, there was statistically no significant difference (P > 0.05). Disregarding regions, HPV/control and HPV/ASCUS cases stained with PAP and MGG had statistically significant difference in MN count (P < 0.05).Conclusion:These findings suggest that MGG and PAP staining gives similar results with regard to MN count. On the other hand, it has been shown again that HPV induces MN and causes genomic instability.

Evaluation of the genotoxic potential of different delivery methods of at-home bleaching gels: a single-blind, randomized clinical trial.

This single-blind, parallel, randomized clinical trial evaluated the genotoxic potential and effectiveness of 10% hydrogen peroxide (HP) in patients submitted to at-home bleaching. Sixty young volunteers with maxillary incisors equal to or darker than M1.5 were included in the study. Patients were submitted to bleaching for 14days (30min/day) with one of the three 10% HP treatments: the bleaching agent was delivered in a bleaching tray (White Class, FGM), whitening strips (White Strips, Oral-b), or in prefilled disposable trays (Opalescence Go, Ultradent). The color change was evaluated with the Vita Bleachedguide, and the micronucleus test of exfoliative oral mucosa was carried out, starting from a count of 1000 cells, at the baseline, immediately after and 30days after the end of the treatment. The micronucleus data were evaluated with the Kruskal-Wallis and Wilcoxon tests and color change with the two-way ANOVA test and the Tukey test (α = 0.05). Significant whitening was observed for all groups after 14days (p = 0.001) and was maintained after 30days, with no difference between groups (p = 0.42). The micronucleus count did not indicate genotoxic potential in any of the groups studied (p = 0.32), irrespective of the time intervals (p = 0.62). No genotoxic effects of 10% HP were observed in patients submitted to at-home bleaching systems (30min/day for 14days), even 30days after the end of treatment. It is safe to use different systems to deliver 10% HP during at-home bleaching according to the manufacturers' recommendations, with no risk of genotoxic effects applied.

Increased micronucleus count predicts malignant behavior in pleural effusion fluid

Background/aim: Micronucleus (MN) frequency is used as a biomarker of chromosomal damage, genome instability, and cancer risk. The aim of this study was to evaluate the diagnostic usefulness of MN frequency to differentiate between malignant and benign pleural effusion samples. Materials and methods: Retrospectively, 78 pleural fluid cytology samples (including 20 cases of benign reactive mesothelial cells, 22 cases of suspicious cytology, and 36 cases of malignant cytology) were examined. The number of micronucleated cells in 1000 well- preserved cells was counted. Statistical tests were performed to compare the study groups. Recover operating characteristics (ROC) curve analysis was performed to suggest a cut-off value for predicting malignant behavior. Results: We evaluated a total of 78 cases of pleural effusion cytology. The number of micronucleated cells was significantly higher in cases with malignant outcome compared to cases with benign outcome. We observed that malignant samples had more micronucleated cells than suspicious ones, and suspicious cases had more micronucleated cells than reactive ones. There was a significant difference among all study groups. In addition, the frequency of MN-containing cells in suspicious cases correlates well with their outcomes. Conclusion: The results of this study reveal that there is an absolute, consistent, and proportional relationship between MN counts and malignancy in cytological samples of pleural effusions. MN scoring may be a helpful diagnostic tool for distinguishing malignant effusions from benign ones, and may be used as an adjunct tool to predict malignant behavior in challenging cases.