Potential uses, limitations, and basic procedures of micronuclei and nuclear abnormalities in buccal cells

Evaluation of micronuclei, cytomorphometric and cytologic changes of the oral mucosa in hookah and cigarette smokers

OBJECTIVE

To analyze the effect of hookah and cigarettes on the oral mucosa of smokers through the use of exfoliative cytology.

STUDY DESIGN

Smear samples were collected by exfoliative cytology from the tongue of 33 hookah smokers, 22 cigarette smokers, and 30 non-smokers. The selected analyses include micronuclei (MN), metanuclear anomalies, epithelial maturation, and cytomorphology (nuclear area [NA], cytoplasmic area [CA], and NA/CA ratio).

RESULTS

The largest differences observed for MN and metanuclear anomalies were between cigarette smokers and the control group (notably 1 MN P = .04; total cells with MN P = .039; total MN P = .042; karyorrhexis and binucleation, P = .0001). The hookah group, compared with the control group, showed the greatest differences for karyolysis (P = .0023), binucleation (P = .0003), and broken egg (P = .008). Significant differences were found between the smokers and the control groups regarding changes in the superficial cell without nucleus, perinuclear halo, vacuolization, color change, mucus, and keratohyalin granules. There was a significant increase in the NA and NA/CA ratio in the smoker groups.

CONCLUSION

This study showed that a combined analysis of exfoliative cytology associated with other diagnostic methods is a useful tool for studying oral carcinogenesis. Hookah and cigarettes showed similar effects in terms of displaying substantial cytogenetic and cytotoxic damage.

Comparative evaluation of mutagenic effects of two cone-beam computed tomography in oral mucosa cells

BACKGROUND

This pilot study aimed to evaluate the mutagenic effects in cells of the oral mucosa after exposure to two different cone beam computed tomography (CBCT).

METHODS

Eighteen adults were submitted to the different CBCT (Carestream CS8100 3D and I-CAT). The cells were collected immediately before the CBCT exposure and 10 days later, when the material was placed on a slide and stained using the Feulgen/Fast Green technique. Microscopic analysis counted micronuclei and other nuclear alterations, which are indicative of cytotoxicity such as pyknosis, karyolysis, karyorrhexis, and binucletion. 2000 cells were analyzed. The statistical analysis was performed with the Wilcoxon Signed-Rank test to compare the frequency of cellular alterations, and the Mann-Whitney U test to compare different CBCTs, both with a significance level of 5%.

RESULTS

There was no statistically significant difference in the micronucleated cell count before and after the exposition to the ionizing radiation from I-CAT (p = .298) and CS8100 3D (p = .203) A significate increase of pyknosis (p < .001), karyolysis (p < .001), karyorrhexis (p < .001), and binucletion (p < .001) were noted on I-CAT CBCT. There was no statistically significant difference in cellular alterations in CS8100 3D CBCT.

CONCLUSION

Despite the increase in micronuclei after exposure, this study indicates that there is no evidence of genotoxicity. On the other hand, the I-CAT CBCT produced cytotoxic effects.

Genotoxic and Cytotoxic Effects of Cone Beam Computed Tomography and Multidetector Computed Tomography on Exfoliated Buccal Epithelial Cells

Background

Cone beam computed tomography (CBCT) and multidetector computed tomography (MDCT) are frequently used in dental and maxillofacial problems. This study aimed to assess the genotoxicity and cytotoxicity effects of CBCT and MDCT radiographies on exfoliated buccal epithelial cells during dental examinations.

Methods

This prospective experimental study was conducted at Babol University of Medical Sciences (Babol, Iran) from March 2021 to April 2021. Buccal mucosa smears were collected bilaterally pre-exposure and 12 days after CBCT or MDCT examinations. To compare the frequency of micronuclei and other cytotoxic cellular changes such as pyknosis, karyolysis, and karyorrhexis, the paired sample t test and Wilcoxon test were used. In addition, independent sample t test, Mann-Whitney, and Chi square tests were used to investigate the differences between the imaging methods and between men and women. All statistical analyses were performed using the SPSS software, and P≤0.05 was considered statistically significant.

Results

The current study included 60 adult patients (30 patients in each group), ranging in age from 21 to 50 years. The micronuclei and the other cytotoxic cellular changes increased significantly after CBCT and MDCT radiographic examinations on the 12th day compared to the pre-exposure results (P<0.001). MDCT had statistically higher cytotoxic and genotoxic effects than CBCT (9.4%, 23.1%, and 40% higher values in micronucleus frequency, the mean frequency of micronuclei, and other cytotoxic changes, respectively). There were no significant differences between men and women in the two examination methods (P=0.46 and P=0.49, respectively).

Conclusion

Dental examinations with CBCT and MDCT can increase cytotoxicity and chromosomal damage in both men and women. Due to its lower radiation toxicities, CBCT can be recommended as an alternative to MDCT for dental examinations.

Artisanal Gem Mining in Brazil: A Source of Genotoxicity and Exposure to Toxic Elements

Environmental and occupational exposure to toxic metals has led many people around the world to have serious health problems. Mining activities contribute to an increased risk of exposure to these elements. In this work, a study of environmental biomonitoring and routes of exposure to toxic metals in a region of artisanal mining was performed. This study was carried out in the district of Taquaral de Minas, located in the Jequitinhonha Valley in the state of Minas Gerais. The valley is one of the wealthiest and highest gem-producing areas in Brazil. Five artisanal mines were sampled (Bode, Pirineu, Pinheira, Lajedo, and Marmita). Several potentially toxic metals (Be, Zn, Mn, Ba Cd, Hg, and U) were investigated in the soils and dust over the rocks and the soils. Samples from 22 individuals occupationally exposed and 17 unexposed persons, who formed the reference group, were analyzed for trace elements by an inductively coupled plasma mass spectrometer. The genotoxicity was evaluated by the micronucleus test in buccal mucosa epithelial cells, where the following changes were scored: micronuclei (MN) binucleate (BN) cells and kariolytic (KL) cells. The MN test showed significantly increased frequencies in all alterations of exposed individuals compared to the controls (p < 0.05, Student's t-test). The urine analysis showed levels of Cr, Ni Ba, Pb, and As in the blood, which were higher than the ATSDR recommended levels. The association between the MN test and the trace element concentrations found in the blood and urine was significant (p < 0.05). The higher the number of years of working, the higher the concentrations in the blood were, due to chronic exposure. The results of the present study indicate environmental contamination and a potential risk to the health of miners, suggesting an intervention.

Use of liquid-based cytology samples reveals genomic instability and cell death in patients undergoing orthodontic treatment

PURPOSE

To examine the use of liquid-based exfoliative cytology to determine the presence of genomic instability and cell death in the oral mucosa of patients with orthodontic appliances.

METHODS

Fifty-four oral mucosa samples were collected from 18 patients and divided into three stages: T0, before fixation of orthodontic appliances; T1, 25 days after appliance fixation; T2, 90 days after appliance fixation. All samples were Papanicolaou-stained and observed by microscopy (1,000 cells/sample) to ascertain the frequency of micronucleated cells (MN) and nuclear abnormalities (nuclear buds (NB), binucleated (BN), condensed chromatin (CC), karyorrhexis (KR), and karyolysis (KL)). Differences were analyzed statistically using the Mann-Whitney, Wilcoxon, Kruskal-Wallis and chi-squared tests.

RESULTS

After placement of orthodontic appliances, significant differences were observed for genomic instability biomarkers (MN and NB) and cell death (CC, KR and KL) (P < 0.05). Female patients and older patients exhibited a higher frequency of MN.

CONCLUSION

Liquid-based cytology has revealed that orthodontic appliances induce genomic instability and cell death in epithelial tissue of the oral mucosa, facilitating sample preservation and yielding more than one preparation per sample. Future studies should investigate whether such cell damage can be reversed through cell repair or whether cell alterations evolve and lead to disease.

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.

Age features of buccal epithelium in practically healthy people

Recently, buccal epithelium has been used to study age-dependent processes. This approach is of particular relevance due to its non-invasiveness. The purpose of this study is to establish the normal values of the buccal cytogram in different age groups, including athletes. 200 practically healthy volunteers of different ages were examined, who were divided into 5 groups in accordance with the WHO age classification. In addition, 125 professional athletes took part in the study. All patients underwent a comprehensive dental examination and a standard cytological examination of buccal smears. It has been established that the cytological characteristics of buccal epitheliocytes, indirectly reflecting disorders of the nuclear apparatus of the cell, did not change significantly with age, but there was a certain upward trend in the number of cells with such anomalies (micronucleus, protrusions).The number of binuclear cells and the apoptotic index also slightly increase with age. At the same time, a high positive correlation was found between the apoptosis index and senile age. In young athletes, an increase in the number of buccal epitheliocytes with a perinuclear vacuole (an early sign of cell damage) was foundAnalysis of the cytological examination results of the buccal epithelium in people a slight increase in the level of cytological abnormalities in old age, in particular, signs of apoptosis. In addition, in healthy young athletes (18 years old - 44 years old), an increase in the number of cells with signs of nuclear degradation, which most likely reflects increased mechanical stress on the maxillofacial apparatus during sports activities.

Current Scientific Research Trends on Salivary Biomarkers: A Bibliometric Analysis

Salivary biomarkers are indicators of many biological and pathological conditions and provide further information regarding the early detection of diseases. This bibliometric analysis aims to identify and evaluate the scientific literature addressing salivary biomarkers from a dental perspective, to identify the most prolific organizations, authors, journals, countries, and keywords used within this research domain. An electronic search was performed using Elsevier’s Scopus database. From a total of 587 retrieved papers (published between 1997 and 2021), 399 were selected. For the data analysis and its visualization, the title of the articles, year of publication, countries, authors, journals, articles, and keywords were analyzed using Microsoft Excel and VOSviewer (a bibliometric software program). An increase in the number of publications was identified from 1997 to 2021. The United States (U.S.) published the most papers (84) and received the highest citations (3778), followed by India and Brazil. The Journal of Periodontology published the highest number of articles (39) that received the highest citations. The University of Kentucky from the U.S. published most of the papers related to salivary biomarkers that received the highest citations. Timo Sorsa published the most papers (14 papers), while Craig Miller was the highest cited author (754 citations). Concerning the highly cited papers, a paper by Micheal et al., published in 2010, received the highest citations (487 citations). “Saliva”, followed by “human”, were the most common keywords used by the authors in the papers related to salivary biomarkers. The findings of this analysis revealed an increase in salivary biomarker-related publications that positively influenced the number of citations each paper received. The U.S. produced the most publications that received the highest citations, and the University of Kentucky, U.S., was the most prominent. The articles were mostly published in the Journal of Periodontology and received the highest number of citations.

Biomonitoring of workers employed in a titanium dioxide production plant: Use of buccal micronucleus cytome assay as noninvasive biomarker to evaluate genotoxic and cytotoxic effects

We aimed to evaluate whether TiO₂ production process induces genotoxic and cytotoxic effects on the first target organ of inhalable particles by a sensitive and noninvasive biomarker of effect. Final aim was to find a useful and suitable tool to assess and manage the risk of TiO₂ occupational exposure. We enrolled 40 workers employed in TiO₂ production, 5 office workers, and 18 external controls. Buccal micronucleus cytome assay (BMCyt assay) was applied because it allows to evaluate micronucleus (MN), nuclear buds (NB), and broken eggs (BE) indicating the presence of chromosomal instability and gene amplification and binucleated cells (BIN), karyolytic cells (KL), and condensed chromatin (CC) indicating cytokinesis defect or arrest, cell death and apoptosis respectively. We characterized the exposure measuring inhalable and respirable particles by personal monitoring. BMCyt-assay showed in exposed workers compared with external controls a higher value of MN frequency (2.57 vs. 0.05‰, p < .001) and MN positivity, evaluated as percentage of subjects with MN frequency higher than a 1.5‰ cut-off value (52.5 vs. 0%). We also found in exposed workers higher frequency of BE + NB (2.41 vs. 0.22‰, p = .002), BIN (9.45 vs. 8.44‰, p = .047) and CC (1.80 vs. 0.21, p = .001) than in controls. Moreover, we found a relationship between personal monitoring results and presence of MN and other cellular anomalies. This study demonstrates induction of genotoxic and cytotoxic effects on buccal cells of workers involved in TiO₂ production, suggesting the suitability of BMCyt assay as tool for risk assessment and management of TiO₂ exposure.

E-cig might cause cell damage of oral mucosa

OBJECTIVE

The aim of this study was to investigate cytogenetic and cytotoxic damage through the evaluation of micronuclei (MN) and metanuclear anomalies in the oral mucosa of electronic cigarette (e-cig) users.

STUDY DESIGN

The patients were recruited into 4 groups: e-cig users, smokers, former smokers, and nonsmokers (control). The samples were collected by means of exfoliative cytology of the lateral region of the tongue and the floor of the mouth. The smears obtained were fixed and stained by the Feulgen method for investigation of MN and metanuclear anomalies.

RESULTS

A significant difference was observed for MN frequency only between the smoker and control groups. As for metanuclear anomalies, significant differences were observed: karyolysis between: smokers and control, e-cig and control, as well as former smokers; karyorrhexis: between smoker and control; binucleation: between e-cig and former smoker, as well as control; broken eggs: between e-cig and all other groups; nuclear bud: between e-cig and former smokers, as well as control.

CONCLUSIONS

E-cig and alcohol users presented genotoxicity and cytotoxicity in the oral mucosa cells. The use of e-cigs and alcohol by former smokers can cause more damage to the cells of the oral mucosa compared to those who have not used e-cigs.

Cytogenotoxicity Evaluation of Young Adults Exposed to High Levels of Air Pollution in a Mexican Metropolitan Zone Using Buccal Micronucleus Cytome Assay

Air pollution has become a serious public health problem globally. Recent studies support the harmful effect of air pollution on human health, in addition to scientific evidence that recognizes it as a human carcinogen. The buccal micronucleus cytome (BMC) assay is employed extensively to measure cytotoxic and genotoxic damage in a population exposed to environmental contamination. The objective of this study was to evaluate the cytotoxic and genotoxic effects in healthy young adults exposed to different levels of air pollution and to identify areas with air pollution rates above the regulatory limits. This study was performed through the BMC assay in oral mucosa samples from 80 healthy young adults from the Guadalajara metropolitan zone. Three highly contaminated areas were taken into account: Tlaquepaque, Miravalle, and Las Pintas. Las Aguilas, a less contaminated area, was used as a reference. The frequencies of nuclear abnormalities in the areas with the highest and lowest levels of air pollution were compared with the Mann–Whitney U test. In addition, an analysis of the concentration of environmental pollutants, particulate matter ≤ 10 μm (PM10), ozone (O₃), nitrogen dioxide (NO₂), sulfur dioxide (SO₂), and carbon monoxide (CO), were carried out in the mentioned areas, in order to identify the events above the regulatory limits in a year period. The results showed that young adults exposed to a higher concentration of pollutants showed higher frequencies of nuclear abnormalities. The individuals from the areas of Tlaquepaque, Miravalle, and Las Pintas showed cytotoxic damage since statistically significant differences were found in the abnormalities of pyknotic nuclei (PNs), condensed chromatin (CC), karyorrhexis (KX), and karyolysis (KL). The individuals who showed the most cytotoxic damage were from the Las Pintas area with higher frequencies in nuclear abnormalities (PNs, CC, KX, and KL) (p < 0.0001). Genotoxic damage was found in individuals from two zones, Miravalle and Las Pintas, with statistically significant differences in the abnormality of nuclear buds (NBUDs) (p < 0.0001). Our results suggest that exposure to high levels of air pollution in healthy young adults has an effect on cellular and nuclear integrity and thus in human health, since areas with higher air pollution showed an increase in cytotoxicity, specifically in early and late markers of cell death (CC, KX, PN, and KL) and genotoxic damage (BUDs).

Micronucleus Test Reveals Genotoxic Effects in Bats Associated with Agricultural Activity

Bats play a vital role in our ecosystems and economies as natural pest-control agents, seed dispersers, and pollinators. Agricultural intensification, however, can impact bats foraging near crops, affecting the ecosystem services they provide. Exposure to pesticides, for example, may induce chromosome breakage or missegregation that can result in micronucleus formation. Detection of micronuclei is a simple, inexpensive, and relatively minimally invasive technique commonly used to evaluate chemical genotoxicity but rarely applied to assess wildlife genotoxic effects. We evaluated the suitability of the micronucleus test as a biomarker of genotoxicity for biomonitoring field studies in bats. We collected blood samples from insectivorous bats roosting in caves surrounded by different levels of disturbance (agriculture, human settlements) in Colima and Jalisco, west central Mexico. Then, we examined the frequency of micronucleus inclusions in erythrocytes using differentially stained blood smears. Bats from caves surrounded by proportionately more (53%) land used for agriculture and irrigated year-round had higher micronucleus frequency than bats from a less disturbed site (15% agriculture). We conclude that the micronucleus test is a sensitive method to evaluate genotoxic effects in free-ranging bats and could provide a useful biomarker for evaluating risk of exposure in wild populations. Environ Toxicol Chem 2021;40:202-207. © 2020 SETAC.

Retinol palmitate against toxicogenic damages of antineoplastic drugs on normal and tumor cells

The lack of tissue selectivity of anticancer drugs generates intense collateral and adverse effects of cancer patients, making the incorporation of vitamins or micronutrients into the diet of individuals to reduce side or adverse effects of antineoplastics. The study aimed to evaluate the effects of retinol palmitate (RP) on the toxicogenic damages induced by cyclophosphamide (CPA), doxorubicin (DOX) and its association with the AC protocol (CPA + DOX), in Sarcoma 180 (S-180) tumor cell line, using the micronuclei test with a block of cytokinesis (CBMN); and in non-tumor cells derived from Mus musculus using the comet assay. The results suggest that CPA, DOX and AC protocol induced significant toxicogenic damages (P < 0.05) on the S-180 cells by induction of micronuclei, cytoplasmic bridges, nuclear buds, apoptosis, and cell necrosis, proving their antitumor effects, and significant damage (P < 0.001) to the genetic material of peripheral blood cells of healthy mice, proving the genotoxic potential of these drugs. However, RP modulated the toxicogenic effects of antineoplastic tested both in the CBMN test (P < 0.05), at the concentrations of 1, 10 and 100 IU/mL; as in the comet assay (P < 0.001) at the concentration of 100 IU/kg for the index and frequency of genotoxic damage. The accumulated results suggest that RP reduced the action of antineoplastics in non-tumor cells as well as the cytotoxic, mutagenic, and cell death in neoplastic cells.

Genotoxicity and mutagenicity research in Quilombola communities

The Quilombola communities are mostly isolated and deprived of sources of treated water, garbage collection and sewage, consuming fresh water from wells, streams, lakes, among others. This lack of basic infrastructure can be a relevant factor in exposing residents to substances and factors that are harmful to the integrity of their genetic material that can lead to carcinogenesis. Based on this, the objective of this study was to evaluate the genomic and mutagenic/cytotoxic damage in the adult population of two Quilombola communities (one urban and another rural region), in the state of Goiás, Brazil. For this purpose, the leukocyte of peripheral blood Comet Assay in 68 individuals and Micronucleus Test from exfoliated buccal cells of oral mucosa in 21 volunteers were performed. The results evidenced genomic damage, especially for the community of Aparecida de Goiânia city, which detected significant values (p < 0.05), for the length of the comet's tail and for of the Olive Tail Moment. In the micronucleus test, significant differences were only detected (p < 0.05), when it came to the distribution of nuclear changes among the groups. Therefore, it is essential to perform constant population biomonitoring studies to help guarantee health and, consequently, the quality of life.

Genetic Instability of a Polydactyl Hypopigmented Cat With Squamous Cell Carcinoma-A Case Report

Polydactyly, hypopigmentation, and squamous cell carcinoma are common in cats. However, a cat exhibiting all of these conditions has not yet been reported. This study presents the case of a 14- year-old male Mexican cat, hypopigmented, with supernumerary fingers, two preaxial and one on each posterior limb, admitted to the clinic with a lesion in the left periocular region. The cat was subjected to a general physical examination, blood, and urine chemistry, as well as a biopsy and genomic instability assessment with an analysis of the red blood cells (RBC) micronucleated erythrocytes (RBC-MNE) in the peripheral blood. The biopsy was positive for squamous cell carcinoma, and the RBC-MNE count (8.6 MNE/1000 erythrocytes) was high compared to that previously described in other domestic cats or wild cats. Thus, the genomic instability of the RBC-MNE could be used as an indicator to identify clinical conditions of felines, particularly those with one of the characteristics exhibited by this Mexican cat. The RBC-MNE test is the most widely used in the world for the evaluation of DNA damage, but to our knowledge, it has not been used to identify vulnerable non-human specimens.

Evaluation of Anti-Cytotoxic and Anti-Genotoxic Effects of Nigella sativa through a Micronucleus Test in BALB/c Mice

Nigella sativa (N. sativa) is a medicinal plant used for its therapeutic pharmacological effects such as anti-inflammatory, antioxidant, anticancer, antidiabetic, and immunomodulation. This study explored the anti-cytotoxic and anti-genotoxic effect of N. sativa through a micronucleus test (MNT) of BALB/c mice peripheral blood. Using 6-to-8-week-old healthy male BALB/c mice, four groups were formed: (1) Control (sterile water), single-dose 2 mg/kg/intraperitoneal (i.p); (2) N. sativa oil, 500 mg/kg/24 h/7 days/i.p; (3) Cisplatin (CP), single-dose 2 mg/kg/subcutaneous (s.c); (4) N. sativa + CP with their respective dosage. When evaluating polychromatic erythrocytes (PCE), a biomarker of cytotoxicity, the group treated with N. sativa + CP experienced an increase in the frequency of PCE, which demonstrated the recovery of bone marrow and modulation of cell proliferation. The analysis of micronucleated polychromatic erythrocytes (MNPCE), an acute genotoxicity biomarker, showed similar frequency of MNPCE within the groups except in CP, but, in the N. sativa + CP group, the frequency of MNPCE decreased and then regulated. Finally, the frequency of micronucleated erythrocytes (MNE), a biomarker of genotoxicity, the supplementation of N. sativa oil did not induce genotoxic damage in this model. Thus, we conclude that N. sativa has both cytoprotective, genoprotective effects and modulates cell proliferation in BALB/c mice.

Indicators of Genotoxicity in Farmers and Laborers of Ecological and Conventional Banana Plantations in Ecuador

Banana farming represents an important segment of agricultural production in Ecuador. The health of farmworkers might be compromised by the extensive use of pesticides in plantations applied under poorly regulated conditions. Due to an increased awareness of pesticide-related problems for nature, as well as for worker and consumer health, ecological farming has been established in some plantations of Ecuador. We set out to investigate the occupational health of workers in both conventional and ecological farming. Nuclear anomalies in buccal epithelial cells were used as short-term indicators for genotoxicity and a potentially increased cancer risk in the two groups of farmworkers. By application of the Buccal Micronucleus Cytome Assay (BMCA), we found the frequency of micronuclei in conventional pesticide using farmworkers significantly increased by 2.6-fold, and other nuclear anomalies significantly increased by 24% to 80% (except pyknosis with a non-significant increase of 11%) compared to the farmworkers on ecological plantations. These results demonstrate that ecological farming may provide an alternative to extensive pesticide use with significantly reduced indicators of cancer risk. In conventional farming, improvements in education and instruction regarding the safe handling of pesticides and protective equipment, as well as regulatory measures, are urgently needed.

In vivo assessment of genotoxicity in buccal cells of children undergoing tooth restoration

OBJECTIVES

Whereas dental materials came in direct or close contact with oral tissue, it is a great concern about the biocompatibility of those materials. This study was performed to evaluate possible DNA damage to buccal cells exposed to dental materials.

METHODS

This prospective, longitudinal clinical study was conducted over a three months period. Class II restorations were placed in 60 young patients with no previous filling using one of three tested dental materials (two glass ionomers; Ketac Molar and Ionofil Molar and one compomer material; Twinky Star). DNA damage was analysed by micronucleus assays, in buccal exfoliated epithelial cells.

RESULTS

In patients treated with Ketac Molar, a significant frequency of micronuclei (p = 0.027) and binucleated cells in samples taken 30 days following restoration (p = 0.029) was confirmed. In patients treated with Twinky Star, a statistically significant increase in the number of binucleated cells in samples taken after 7 and 30 days following restoration (p = 0.001 and p < 0.001, respectively) was observed. In all samples collected 90 days after treatment, there was no statistical difference in the number of any cell changes.

CONCLUSION

In this study long-term biocompatibility of tested materials was confirmed. Glass ionomers and compomers are widely used materials in paediatric dentistry, and this study has proved their safety for usage in children.

Assessment of genotoxic effects on elderly populations exposed to high traffic areas: Results for supporting public health surveillance

In urban areas with intense vehicular traffic, particulate matter in suspension, especially the fraction of particles with ultra-fine diameter, has been regarded as the main problem of chronic diseases in susceptible populations, such as the elderly. This study aimed to determine the genotoxic effects of exposure to air pollution evaluating the association between the frequencies of micronuclei (MN) and binucleated (BN) cells in exfoliated oral mucosa cells of elderly population and exposure conditions, considering the influence of traffic and concentration of PM in different aerodynamic diameters. Traffic of passenger vehicles, heavy duty trucks and environmental concentrations of Particulate Matter were measured twice a day during 28 days before biological sampling of oral mucosa from 154 participants living in areas of distinct levels of urban traffic. Data from this study showed that the group of participants living near road traffic exhibited higher MN cell frequency, when compared to the other groups of subjects. In addition, a canonical correlation analysis between environmental and genotoxicity variables analysis revealed that high concentrations of the particulate matter were correlated with intense traffic and the genotoxicity in exfoliated oral cells.

Method validation to assess in vivo cellular and subcellular changes in buccal mucosa cells and saliva following CBCT examinations

OBJECTIVES

Cone-beam CT (CBCT) is a medical imaging technique used in dental medicine. However, there are no conclusive data available indicating that exposure to X-ray doses used by CBCT are harmless. We aim, for the first time, to characterize the potential age-dependent cellular and subcellular effects related to exposure to CBCT imaging. Current objective is to describe and validate the protocol for characterization of cellular and subcellular changes after diagnostic CBCT.

METHODS

Development and validation of a dedicated two-part protocol: 1) assessing DNA double strand breaks (DSBs) in buccal mucosal (BM) cells and 2) oxidative stress measurements in saliva samples. BM cells and saliva samples are collected prior to and 0.5 h after CBCT examination. BM cells are also collected 24 h after CBCT examination. DNA DSBs are monitored in BM cells via immunocytochemical staining for γH2AX and 53BP1. 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) and total antioxidant capacity are measured in saliva to assess oxidative damage.

RESULTS

Validation experiments show that sufficient BM cells are collected (97.1 ± 1.4 %) and that γH2AX/53BP1 foci can be detected before and after CBCT examination. Collection and analysis of saliva samples, either sham exposed or exposed to IR, show that changes in 8-oxo-dG and total antioxidant capacity can be detected in saliva samples after CBCT examination.

CONCLUSION

The DIMITRA Research Group presents a two-part protocol to analyze potential age-related biological differences following CBCT examinations. This protocol was validated for collecting BM cells and saliva and for analyzing these samples for DNA DSBs and oxidative stress markers, respectively.

Evaluation of Genotoxicity by Micronucleus Assay in vitro and by Allium cepa Test in vivo

The in vitro and in vivo genotoxicity of new metallodrugs either as Small Bioactive Molecules (SBAMs) or Conjugates of Metals with Drugs (CoMeDs) is evaluated by the micronucleus test and the Allium cepa assay, respectively. Fetal lung fibroblast cells (MRC-5), normal human corneal epithelial cells (HCEC) and immortalized human keratinocytes cells (HaCaT) were incubated with solutions of SBAMs or CoMeDs at their IC₅₀ values for 48 h (the concentration of a compound which is required to inhibit the cells growth by 50% in relation to the non-treated cells). The micronucleus abundance percentage towards the corresponding one, of the non-treated cells indicates the in vitro genotoxicity of the formulations. The in vivo Allium cepa test comprises the exposing of the plant Allium cepa roots to an SBAMs or a CoMeDs solution for 48 h. The percentages of the mitotic index, the chromosome aberrations, the nuclear abnormalities and the presence of the micronucleus are calculated indicating the in vivo genotoxicity of the agent.

Diclofenac conjugates with biocides through silver(I) ions (CoMeD's); Development of a reliable model for the prediction of anti-proliferation of NSAID's-silver formulations

The conjugation of diclofenac (DICLH), a Non-Steroidal Anti-inflammatory Drug (NSAID), with biocides such as dimethyl sulfoxide (DMSO) and triphenylphosphine (TPP), through silver(I) ions, results into the chemical [Ag_n(DICL)_n(L)_m]_k (L = DMSO and n = 2, m = 2, k = infinite (1); L = TPP and n = 1, m = 2, k = 1 (2)). The compounds were characterized by m.p., FT-IR, UV-vis and ¹H NMR spectroscopic techniques. The crystal and molecular structures of 1-2 were determined by X-ray crystallography. The in vitro cytotoxic activity of 1-2 against the human breast adenocarcinoma cancer cells MCF-7 (hormone dependent) and MDA-MB-231 (hormone independent) reveals that the 1 inhibits the MCF-7 rather than the MDA-MB-231 cells, suggesting hormone mimetic behaviour. Compound 2 inhibits both cancerous cell lines, stronger than cisplatin. Both compounds inhibit MCF-7 cells migration. Compounds 1-2, exhibit, lower toxicity against fetal lung fibroblast (MRC-5) cells than cisplatin. Their genotoxicity was evaluated on MRC-5 cells. The molecular mechanism of 1-2 against MCF-7 cells was clarified by (i) their cell cycle arrest study (ii) their mitochondrial membrane permeability (iii) their binding affinity towards Calf Thymus (CT)-DNA and (iv) their inhibitory activity against the enzyme lipoxygenase (LOX). Regression analysis of the data obtained for [Ag(NSAID)(Ar₃P)_m] (NSAID = p‑hydroxy‑benzoic acid (p-HO-BZAH), salicylic acid (SALH₂), aspirin (ASPH), naproxen (NAPRH), nimesulide (NIMH); L = TPP, Tri(p‑tolyl)phosphine (TPTP), Tri(o‑tolyl)phosphine (TOTP), Tri(m‑tolyl)phosphine (TMTP); m = 2 or 3) and [Ag(DICL)₂(DMSO)₂]_k (k = infinite) was performed. Considering the biological results (IC₅₀) as dependent variable a theoretical equation is obtained for these compounds. The calculated IC₅₀ values are compared satisfactorily with the corresponding experimental inhibitory activity of the complexes.

Comparative Study using Papanicolaou Stain and Silver-stained Nucleolar Organizer Region Counts in Exfoliative Smear of Oral Mucosa in Bidi Smokers and Nonsmokers

Aim:

The aim of this study is to compare the proliferative activity of exfoliated cells in bidi smoker's and nonsmoker's oral mucosa.

Materials and Methods:

The oral mucosal exfoliate smears were prepared from 40 individuals (20 nonsmokers and 20 smokers) with the age group ranging from 25 to 70 years, in and around Akola (Maharashtra). The Papanicolaou (PAP) stain and silver-stained nucleolar organizer region (AgNOR) were used to prepare cytogenic smear to evaluate the presence of cytological alterations, suggestive of inflammation, dysplasia, keratinization, and proliferative activity of epithelial cells. The present study involves PAP Class I and Class II smears. The obtained data were tabulated and statistically analyzed using statistical software IBM SPSS IBM Corp., Statistics for Windows, Version 20.0. Armonk, NY, USA: IBM Corp., and using t-test.

Results:

There was a significant difference in mean number of AgNORs/nucleus between nonsmokers (0.947 ± 0.2533) and smokers (3.021 ± 0.2256). There were 90% inflammatory changes observed in smokers whereas nonsmokers showed only 75% changes. PAP Class II changes, i.e., significant proliferative activity, were found between smokers and nonsmokers mucosa.

Conclusion:

A significant difference of AgNORs/nucleus was found between nonsmokers and smokers.

Silver ciprofloxacin (CIPAG): a successful combination of chemically modified antibiotic in inorganic-organic hybrid

The new silver(I) ionic, water soluble, compound {[Ag(CIPH)₂]NO₃∙0.75MeOH∙1.2H₂O} (CIPAG) was obtained by reacting silver(I) nitrate with the antibiotic ciprofloxacin (CIPH). The complex was characterized by m.p., mid-FT-IR, ¹H-NMR, UV-Vis spectroscopic techniques. The crystal structures of both CIPAG and the hexahydrated neutral free drug {[CIPH]∙6(H₂O)} (2) were characterized by X-ray crystallography. Two neutral ligands are datively bonded to the metal ion through the piperidinic nitrogen atoms forming a cationic {[Ag(CIPH)₂]⁺} counter part which is neutralized by a nitrate group. The antibacterial effect of CIPAG and the commercially available hydrochloric salt of the antibiotic ({[CIPH ₂⁺ ]∙Cl ^- } (3)) were tested against the bacterial species Pseudomonas aeruginosa (PAO1), Staphylococcus epidermidis (St. epidermidis) and Staphylococcus aureus (St. aureus) by the mean of minimum inhibitory concentration, minimum bactericidal concentration and their inhibitory zone (IZ). The influence of CIPAG and 3 against the formation of biofilm of PAO1 or St. aureus was also evaluated by mean of biofilm elimination concentration. The IZ caused by CIPAG which has been loaded in poly-hydroxyethylmethacrylate, is determined. The genotoxicity of CIPAG and 3 is tested in vitro against normal human corneal epithelial cells (HCET cells), by the presence of micronucleus in HCET cells and in vivo by mean of Allium cepa test.

Protective effect of Uncaria tomentosa extract against oxidative stress and genotoxicity induced by glyphosate-Roundup® using zebrafish (Danio rerio) as a model

Oxidative stress and DNA damage are involved in the glyphosate-based herbicide toxicity. Uncaria tomentosa (UT; Rubiaceae) is a plant species from South America containing bioactive compounds with known beneficial properties. The objective of this work was to evaluate the antioxidant and antigenotoxic potential of UT extract in a model of acute exposure to glyphosate-Roundup® (GR) in zebrafish (Danio rerio). We showed that UT (1.0 mg/mL) prevented the decrease of brain total thiols, the increase of lipid peroxidation in both brain and liver, and the decrease of liver GPx activity caused after 96 h of GR (5.0 mg/L) exposure. In addition, UT partially protected against the increase of micronucleus frequency induced by GR exposure in fish brain. Overall, our results indicate that UT protects against damage induced by a glyphosate-based herbicide by providing antioxidant and antigenotoxic effects, which may be related to the phenolic compounds identified in the extract.

Analysis of various effects of abamectin on erythrocyte morphology in Japanese quails (Coturnix japonica)

Although previous studies have already confirmed the toxicological potential of abamectin (ABA) in different experimental models (from invertebrates to vertebrates), almost nothing is known about the impacts the exposure to this pesticide can cause on birds. Thus, the aim of our study is to investigate the cytotoxic effects on the erythrocytes of female Japanese quails (Coturnix japonica) exposed to low abamectin concentrations. In order to do so, three experimental groups were proposed: "control," composed of quails exposed to abamectin-free drinking water; "ABA 1% median lethal dose (LD₅₀)," comprising birds exposed to water containing 15.5 mg a.i./L of abamectin (via commercial formulation Kraft® 36EC), and "ABA 10% LD₅₀," composed by birds exposed to water containing 155.0 mg a.i./L of abamectin. The micronucleus test and the tests applied to other nuclear abnormalities in the peripheral blood of birds were conducted 40 days after exposure. Our study revealed significant physical abnormalities in nuclear shapes (erythrocytes with asymmetric constriction nuclei, notched nuclei, indented and moved nucleus) of those birds exposed to higher abamectin levels. When all nuclear abnormalities were tallied, a significant dose-dependent trend was noted. Therefore, our study presents initial imprints on determination of abamectin-mediated cellular toxicity in avifauna which can be instrumental in checking polluted ecosystems.

Effects of triclosan on acute toxicity, genetic toxicity and oxidative stress in goldfish (Carassius auratus)

Triclosan (TCS) is used as an antimicrobial agent and has been widely dispersed and detected in the aquatic environment. However, it remains uncertain whether TCS is genotoxic or not. In this study, the acute toxicity of TCS in goldfish (Carassius auratus) was studied. Then, based on the results for acute toxicity, other goldfish were exposed to various concentrations of TCS (control, DMSO control, and 1/4, 1/2, and 1/8 LC₅₀) for 14 days, and the effects on genetic toxicity were evaluated using micronucleus (MN) and nuclear abnormalities (NA) frequencies in peripheral blood and the comet assay in the liver of the goldfish. In addition, malondialdehyde (MDA), reduced glutathione (GSH), catalase (CAT), and total antioxidant capacity (T-AOC) in the liver were assayed to evaluate oxidative stress and the possible mechanism of genotoxicity. The 96 h median lethal concentration of TCS was 1111.9 µg/l. After 14 days of exposure, the MN and NA frequencies were significantly increased in peripheral blood of the TCS-treated groups compared with the solvent control, and the comet tail moment and MDA in the liver in the highest dose of TCS groups were also significantly high. Meanwhile, an evident change in GSH, CAT, and T-AOC of the liver was found as the TCS exposure concentration increased. The results showed that TCS caused oxidative stress and a genotoxic response in goldfish, suggesting that it presents a potential ecotoxicological risk to aquatic ecosystems.

Genotoxicity of non-alcoholic mouth rinses: A micronucleus and nuclear abnormalities study with fluorescent microscopy

AIM

The aim of the present study was to evaluate the genotoxicity of non-alcoholic mouth rinses on buccal epithelial cells using a micronucleus test.

METHODS

A total of 105 patients were selected and randomly divided into five groups. Four different mouth rinses and normal saline were given for 2 weeks' duration, and cytological smears were collected before and after exposure. These smears were subjected to micronucleus (MN) and other nuclear abnormalities (ONA) tests using acridine orange stain, and their frequencies were obtained in 500 buccal epithelial cells. The statistical analysis included mean, χ² -test, analysis of variance, and post-hoc analysis by Bonferroni test.

RESULTS

Micronucleated cells (P < .00) and MN (P < .00) were higher in individuals exposed to chlorhexidine (CHX), followed by chlorine dioxide (ClO₂ ), potassium nitrate (KNO₃ ), and sodium fluoride (NaF), amine fluoride (AmF), and normal saline. ONA were greater (P < .00) in individuals exposed to CHX, followed by ClO₂ , AmF, KNO₃ , and NaF and normal saline. Overall, the results showed that genotoxic damage was greater in the case of CHX, followed by ClO₂ , KNO₃ , and NaF, AmF, and normal saline.

CONCLUSION

Chronic exposure to mouth rinses can cause genotoxic damage to buccal epithelial cells. Long-term injudicious and inadvertent use of mouth rinses should be discouraged.

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

OBJECTIVES

To assess cytological evidence of genotoxicity and cytotoxicity of X-rays in oral exfoliated cells of adults subjected to partial and total cone beam CT (CBCT) (stitching module) by means of micronuclei frequency, associated with counting of degenerative nuclear alterations (pyknosis, karyolysis, karyorrhexis, buds and broken eggs), besides comparing the partial and total CBCT (stitching module) in search of possible differences in the nature and/or intensity of the effects.

METHODS

29 adults who were referred to total or partial CBCT were selected. All CBCT were performed with a Carestream CS 9000 3D scanner (Carestream Health Inc., Rochester, NY). Material collection was done immediately before CBCT and 10 days later, by scraping the left and right cheek mucosa with a plastic spatula. Statistical analysis was performed using the Wilcoxon test (paired data), at a significance level of 5%.

RESULTS

The statistically significant difference was noted in the frequency of micronucleated cells for both partial and total acquisition (p = 0.008 and p < 0.001, respectively). Regarding to cytotoxicity, there was a statistically significant difference for both partial and total acquisition (p < 0.001 and p < 0.001, respectively).

CONCLUSIONS

The partial and total CBCT seems to offer risks of inducing genetic damage. In addition both forms of CBCT acquisition have promoted the induction of cytotoxic nuclear alterations.

Buccal micronucleus cytome assay of populations under chronic heavy metal and other metal exposure along the Santiago River, Mexico

The Santiago River is one of the most contaminated rivers in Mexico, with heavy metal levels above the allowed limits. Scientific evidence indicates that chronic heavy metal exposure leads to cytogenotoxic effects. The aims of this study were to evaluate the genotoxic and cytotoxic effects of such exposure in buccal mucosa cells by micronucleus (MN) assay and to identify other nuclear abnormalities (NAs), such as nuclear buds (NBUDs), binucleated cells (BNs), pyknotic nuclei (PNs), karyorrhexis (KX), karyolysis (KL), and abnormally condensed chromatin (CC). Assays were performed on samples from four populations located alongside the Santiago River that are under chronic exposure to heavy metals and other metals (HMMs), and the results were compared with those of a population without exposure to HMMs. The exposed group showed increased frequencies of NAs (KX, CC, and KL), which are associated with cytotoxic damage, and NBUDs, which are associated with genotoxic damage. Increased frequencies of NBUDs and CC were observed in subjects from El Salto/Juanacatlán, Ocotlán, and Paso de Guadalupe, and an increase in KX frequency was observed in subjects from El Salto/Juanacatlán. Significant differences in KL frequency were observed in subjects from La Barca, El Salto/Juanacatlán, Paso de Guadalupe, and Ocotlán. Predictors for increased development of MNs and NBUDs were high concentrations of Al, Zn, and Cu. In conclusion, chronic exposure to HMMs, especially Al, Cu, and Zn, in the studied population could be related to increased frequencies of NAs, such as NBUDs, KX, CC, and KL, in the buccal mucosa cells.

Inter-laboratory consistency and variability in the buccal micronucleus cytome assay depends on biomarker scored and laboratory experience: results from the HUMNxl international inter-laboratory scoring exercise

The buccal micronucleus cytome (BMNcyt) assay in uncultured exfoliated epithelial cells from oral mucosa is widely applied in biomonitoring human exposures to genotoxic agents and is also proposed as a suitable test for prescreening and follow-up of precancerous oral lesions. The main limitation of the assay is the large variability observed in the baseline values of micronuclei (MNi) and other nuclear anomalies mainly related to different scoring criteria. The aim of this international collaborative study, involving laboratories with different level of experience, was to evaluate the inter- and intra-laboratory variations in the BMNcyt parameters, using recently implemented guidelines, in scoring cells from the same pooled samples obtained from healthy subjects (control group) and from cancer patients undergoing radiotherapy (treated group). The results indicate that all laboratories correctly discriminated samples from the two groups by a significant increase of micronucleus (MN) and nuclear bud (NBUD) frequencies and differentiated binucleated (BN) cells, associated with the exposure to ionizing radiation. The experience of the laboratories was shown to play an important role in the identification of the different cell types and nuclear anomalies. MN frequency in differentiated mononucleated (MONO) and BN cells showed the greatest consistency among the laboratories and low variability was also detected in the frequencies of MONO and BN cells. A larger variability was observed in classifying the different cell types, indicating the subjectivity in the interpretation of some of the scoring criteria while reproducibility of the results between scoring sessions was very good. An inter-laboratory calibration exercise is strongly recommended before starting studies with BMNcyt assay involving multiple research centers.

Genotoxic and Cytotoxic Effects in Exfoliated Buccal and Nasal Cells of Chromium and Cobalt Exposed Electroplaters

Results of a number of studies indicate that electroplaters have increased cancer risks as a consequence of exposure to genotoxic metals such as chromium (VI) and nickel. These effects may be due to induction of damage of the genetic material which plays a key role in the etiology of cancer, and it was found that workers in galvanization factories exhibited increased levels of DNA damage. The aim of the present study was to investigate genetic stability in workers of a bright plating factory who are exposed to chromium (Cr) and cobalt (Co). Exfoliated cells were collected from the buccal and nasal mucosa of workers (n = 42) and matched controls (n = 43) and analyzed for induction of micronuclei (MN) which are formed as a consequence of chromosomal aberrations. In addition, other nuclear anomalies namely nuclear buds (Nbuds) which are formed as a consequence of gene amplification and markers indicating different stages of cell death (condensed chromatin, karyorrhexis, karyolysis, and pyknosis) were also assessed. No evidence was noted for induction of MN, but significantly increased rates of Nbuds in cells from both, buccal and nasal mucosa, were found. Parameters which are indicative for cytotoxic effects were more pronounced in nasal cells and rose with duration of employment period. Overall, our findings indicated that no apparent chromosomal damage occurred in bright electroplaters. However, data demonstrated that acute cytotoxic effects may lead to inflammations and/or lesions in epithelia of the respiratory tract of the workers.

Hydropower reservoirs: cytotoxic and genotoxic assessment using the Allium cepa root model

Hydropower offers a reliable source of electricity in several countries, and Brazil supplies its energy needs almost entirely through hydropower plants. Nevertheless, hydropower plants comprise large buildings and water reservoirs and dams, resulting in huge ecological disruptions. Here, we analyzed the impact of four hydropower reservoirs construction in metals and pesticides incidence and the cytotoxic and genotoxic potential of sediment elutriate of rivers from southern Brazil. Our analyses have evidenced the elevated incidence of different metals (lead, iron, cadmium, and chrome) and pesticides (methyl parathion, atrazine, and 2,4-dichlorophenoxyacetic acid). We showed that Allium cepa exposed to sediment elutriates did not change the seed germination rate and mitotic index. However, roots from Allium cepa exposed to reservoirs sediment elutriates showed increased occurrence of chromosomal aberrations and nuclear abnormalities. Therefore, the results obtained in our study indicate that sediment from reservoirs present elevated concentration of metals and pesticides and a significant genotoxic potential. Taken together, our data support that hydropower reservoirs represent an environmental scenario that could impact surrounding wildlife and population.

Effect of HIV infection in the micronuclei frequency on the oral mucosa

BACKGROUND

The genotoxic impact of HIV infection on the oral cavity malignancies is unknown. The aim of this study was to evaluate the effect of HIV infection in micronucleus (MN) frequency on the oral mucosa of HIV+ patients and establish a relationship with early cytogenetic changes in oral carcinogenesis.

METHODS

Thirty HIV+ individuals who are under highly active antiretroviral therapy (HAART) and 30 non-HIV patients were evaluated. Two smears were taken from the lateral border of the tongue and mouth floor and stained by Feulgen. The frequency of MN was examined in 3000 cells per subject under common microscopy.

RESULTS

MN analysis showed no significant difference between groups by Mann-Whitney U-test for total MNs (P = 0.178). The presence of single MN was greater in control group with statistical significance (P = 0.009), while in HIV group, multiple MNs were exhibited in higher mean.

CONCLUSIONS

HIV patients under HAART therapy and low viral load values showed higher frequency of multiple MNs, which, although not statistically significant, may be caused by the action of the Vpr gene, an accessory gene of HIV. These results corroborate the theory of HIV infection cytogenetic damage.