José Roberto Cardoso Meireles

Genotoxic effects of vehicle traffic pollution as evaluated by micronuclei test in tradescantia (Trad-MCN)

The quality of life in large urban centers is directly affected by the air quality there. Atmospheric monitoring is therefore imperative, and bioassays using plant models to detect the effects of genotoxic agents are recognized as giving excellent results. The present study utilized Trad-MCN to evaluate the genotoxic effects of atmospheric pollutants in the city of Feira de Santana, Bahia State, Brazil, in three locations with varying traffic loads. Inflorescences were collected on a monthly basis from plants growing in these locations in both passive and active monitoring regimes. The occurrence of micronuclei (MCN) was found to be proportional to vehicular flux under both monitoring regimes; with the plants being accompanied by active monitoring demonstrating the greatest sensitivity to atmospheric contamination. The results indicated that locations with the most intense vehicular traffic demonstrated significant atmospheric contamination by pollutants able to damage DNA.

Chromosomal Damage and Apoptosis in Exfoliated Buccal Cells from Individuals with Oral Cancer

This study aimed to investigate cytological abnormalities indicative of chromosome damage (micronuclei) and apoptosis (karyorrhexis, pyknosis, and condensed chromatin) in exfoliated cells from the buccal mucosa of patients with oral cancer and control subjects. The sample included twenty individuals with oral cancer and forty individuals with normal buccal mucosa. Material was collected from the cheek epithelium in areas with lesions and areas without abnormalities. A minimum of one thousand cells was analyzed. Micronuclei were found significantly more frequently in cells collected from lesions than in cells from normal areas, independent of the presence/absence of cancer (P < 0.0001). They were also significantly more frequent in smokers and in mouthwash users (P < 0.0001). Apoptosis occurred significantly less frequently in individuals with oral cancer (P < 0.0001). These results show that oral cancer is associated with higher frequency of chromosomal damage and suggest that apoptosis is compromised in the buccal cells of individuals with this kind of neoplasia.

Genotoxic and cytotoxic effects of testosterone cypionate (deposteron(

The indiscriminate use of anabolic androgenic steroids (AAS) has motivated researchers to investigate the mutagenic action of these substances. The present study, using the mouse bone marrow micronucleus test, evaluates the genotoxic potential of testosterone cypionate (deposteron). Male Swiss mice received intramuscular injections of deposteron at three doses. The animals were sacrificed 24, 48, or 72h after treatment and bone marrow was removed immediately, followed by scoring to count the micronuclei in 2000 polychromatic erythrocytes (PCE). Two hundred erythrocytes/animal were analyzed to determine the PCE-NCE (normochromatic erythrocyte) relationship and to determine the cytotoxic effects. The animals treated with deposteron at the highest dose presented greater numbers of micronuclei. The highest dose caused a decrease in the PCE/NCE relationship, indicating a cytotoxic effect. We conclude that deposteron is genotoxic and cytotoxic in mice.

Chromosomal damage and apoptosis analysis in exfoliated oral epithelial cells from mouthwash and alcohol users

Chromosomal damage and apoptosis were analyzed in users of mouthwash and/or alcoholic beverages, using the micronucleus test on exfoliated oral mucosa cells. Samples from four groups of 20 individuals each were analyzed: three exposed groups (EG1, EG2 and EG3) and a control group (CG). EG1 comprised mouthwash users; EG2 comprised drinkers, and EG3 users of both mouthwashes and alcoholic beverages. Cell material was collected by gently scraping the insides of the cheeks. Then the cells were fixed in a methanol/acetic acid (3:1) solution and stained and counterstained, respectively, with Schiff reactive and fast green. Endpoints were computed on 2,000 cells in a blind test. Statistical analysis showed that chromosomal damage and apoptosis were significantly higher in individuals of groups EG1 and EG3 than in controls (p < 0.005 and p < 0.001, respectively). No significant difference in chromosomal damage and apoptosis was observed between the exposed groups. In EG2, only the occurrence of apoptosis was significantly higher than in the controls. These results suggest that mouthwashes alone or in association with alcoholic drinks induce genotoxic effects, manifested as chromosomal damage and apoptosis. They also suggest that alcoholic drinks are effective for stimulating the process of apoptosis. However, these data need to be confirmed in larger samples.

Assessment of nuclear abnormalities in exfoliated cells from the oral epithelium of mobile phone users.

Abstract Transmission and reception of mobile telephony signals take place through electromagnetic wave radiation, or electromagnetic radiofrequency fields, between the mobile terminal and the radio base station. Based on reports in the literature on adverse effects from exposure to this type of radiation, the objective of this study was to evaluate the genotoxic and cytotoxic potential of such exposure, by means of the micronucleus test on exfoliated cells from the oral epithelium. The sample included 45 individuals distributed in 3 groups according to the amount of time in hours per week (t) spent using mobile phones: group I, t > 5 h; group II, t > 1 h and ≤ 5 h; and group III, t ≤ 1 h. Cells from the oral mucosa were analyzed to assess the numbers of micronuclei, broken egg structures and degenerative nuclear abnormalities indicative of apoptosis (condensed chromatin, karyorrhexis and pyknosis) or necrosis (karyolysis in addition to these changes). The occurrences of micronuclei and degenerative nuclear abnormalities did not differ between the groups, but the number of broken egg (structures that may be associated with gene amplification) was significantly greater in the individuals in group I (p < 0.05).

Effects of age on the frequency of micronuclei and degenerative nuclear abnormalities

O objetivo deste estudo foi avaliar os efeitos do envelhecimento, do genero e de fatores relacionados ao estilo de vida na inducao de danos cromossomicos (micronucleo) e de alteracoes nucleares degenerativas com o uso do teste de micronucleo em celulas esfoliadas da mucosa oral. A amostra incluiu oitenta individuos saudaveis divididos em quatro grupos de acordo com a faixa etaria e o genero: homens e mulheres de 19-29 anos (H19, M19), homens e mulheres com mais de sessenta anos (H60, M60). Questionario de entrevista foi aplicado para caracterizar a amostra e para determinar um indice refletindo o estilo de vida (IVS). A frequencia de micronucleos e alteracoes nucleares degenerativas foi significativamente maior entre os idosos (p 0,05). Ocorrencia de micronucleos foi similar entre homens e mulheres idosos (p>0,10), mas cariorrexis e cariolise foram mais frequentes entre os homens (p<0,005 e p<0,025, respectivamente), que tambem apresentaram o menor IVS em relacao aos demais grupos (p<0,0004). Os resultados deste estudo permitem concluir que a idade foi o principal fator associado a inducao de danos ao material genetico.

Can periodontal infection induce genotoxic effects

Abstract Objective. This study aimed to evaluate the occurrence of chromosomal abnormalities, through micronuclei, and apoptosis by the sum of karyorrhexis, pyknosis and condensed chromatin in individuals with chronic periodontitis, gingivitis associated with biofilm and no periodontal disease. Materials and methods. This study included 72 individuals divided into three groups: gingivitis (n = 21), periodontitis (n = 24) and control (n = 27). Information on sociodemographic characteristics, health and lifestyle was obtained. Full mouth clinical examination was performed to define the periodontal condition. Exfoliated cells from gingival mucosa were collected for computation of micronuclei and nuclear changes indicative of apoptosis. The differences in the occurrence of endpoints (micronucleus, karyorrhexis, pyknosis and condensed chromatin) were evaluated using the conditional test to compare proportions in a rare events situation. Results. There was no statistically significant difference in the occurrence of micronucleus (p > 0.1) between gingivitis, periodontitis and control groups. The occurrence of apoptosis was significantly higher among individuals with periodontitis compared to individuals with gingivitis (p < 0.05) and controls (p < 0.025). Conclusions. The findings showed that the inflammatory process generated by gingivitis and periodontitis is not related to a higher occurrence of chromosomal damage. However, the higher occurrence of apoptosis in individuals with periodontitis points to genotoxic effects induced by periodontal infection.

Chromosome damage, apoptosis, and necrosis in exfoliated cells of oral mucosa from androgenic anabolic steroids users.

The aim of this study was to evaluate the potential of the androgenic anabolic steroids (AAS) for inducing chromosome damage, apoptosis, and necrosis, using the micronucleus test on exfoliated cells from the oral mucosa of AAS users. The sample consisted of 55 male individuals, practitioners of physical exercise divided into two groups: 25 individuals who were users of AAS and 30 individuals in the control group. Cytological analysis included, in addition to micronuclei, counting of broken eggs and degenerative nuclear changes indicative of apoptosis (karyorrhexis, condensed chromatin, and pyknosis) and necrosis (karyolysis in addition to these changes). The statistical analysis did not show differences in occurrences of micronuclei, karyolysis, and broken eggs between the groups. The occurrence of apoptosis was significantly higher in cells from control subjects. The results obtained showed that inhibition of apoptosis was induced by AAS, suggesting that this may be one of the mechanisms contributing toward the association that has been described between use of AAS and the carcinogenic process.

Use of the Micronucleus Test on Tradescantia (Trad-MCN) to Evaluate the Genotoxic Effects of Air Pollution

Good air quality is the fundamental condition for maintaining the equilibrium of human health and ecosystems. However, starting at the time of the industrial revolution, human action has progressively introduced into the atmosphere compounds and particles that compromise the harmony of life on our planet: a process that is known as atmospheric pollution. Thus, atmospheric pollution is defined as the result from excessive introduction of compounds and particles into the air layers that surround Earth (Marcondes, 1993). There are now many sources of atmospheric pollution, and prominent among these are industrial plant, factories and automotive vehicles powered by gasoline and diesel. Among the many pollutants that compromise air quality, particularly in large urban centers, are sulfur dioxide (SO2), carbon monoxide (CO), nitrogen oxides, particles and aromatic polycyclic hydrocarbons, which can combine to form other compounds such as ozone and peroxyacetyl nitrate, thereby giving rise to a complex mixture of pollutants in the atmosphere. The presence of these compounds in the air causes a variety of human health problems, such as abnormalities of the respiratory and cardiovascular systems, allergic reactions and development of lung and tracheal cancer (Brunekreef et al., 2002; Perera et al., 2002; Traversi et al., 2008). Cancer is a disease that results from abnormalities in genes involved in controlling cell proliferation and differentiation and/or genes involved in DNA repair mechanisms and in inducing apoptosis (Hanahan & Weinberg, 2000). The association between atmospheric pollution and cancer therefore comes from the fact that many of the contaminants are mutagens, i.e. they are agents capable of inducing both point mutations (abnormalities involving only one or very few DNA bases) and chromosome aberrations (abnormalities that compromise the structure or the number of chromosomes).