Viviane Carlin

Biomonitoring of oral epithelial cells in smokers and non-smokers submitted to panoramic X-ray: comparison between buccal mucosa and lateral border of the tongue

The aim of the present study was to comparatively evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated oral mucosa cells from smokers and non-smokers submitted to dental X-ray using two anatomic sites: buccal mucosa and lateral border of the tongue. A total of 15 heavy smokers and 17 non-smokers were submitted to panoramic dental radiography for orthodontic reasons. Individuals had epithelial cells from cheek and lateral border of the tongue mechanically exfoliated, placed in fixative, and dropped in clean slides which were checked for the above nuclear phenotypes. The results pointed out no significant statistically differences (p > 0.05) of micronucleated oral mucosa cells before versus after X-ray exposure for both oral sites evaluated either to smokers or to non-smokers. X-ray exposure was able to increase other nuclear alterations closely related to cytotoxicity such as karrhyorexis, pyknosis, and karyolysis for two groups evaluated. Nevertheless, the most pronunciated effects were found to lateral border of the tongue of smokers. In summary, these data indicate that panoramic X-ray is able to induce cellular death in oral mucosa cells. It seems that lateral border of the tongue is more sensitive site to cytotoxic insult induced by ionizing radiation combined with continuous cigarette smoke exposure.

Biomonitoring of mutagenicity and cytotoxicity in patients undergoing fixed orthodontic therapy

INTRODUCTION The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated buccal mucosa cells from adults after fixed orthodontic therapy. MATERIAL AND METHODS A total of 23 healthy adults (10 men and 13 women) undergoing orthodontic therapy were included in this setting. RESULTS The results pointed out no significant statistically differences (P >0.05) of micronucleated oral mucosa cells. In the same way, orthodontic therapy was not able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis (P >0.05). CONCLUSION In summary, these data indicate that orthodontic therapy may not be a factor that induces chromosomal damage, nor it is able to promote cytotoxicity. Since DNA damage and cellular death are important events during carcinogenic processes, especially in early phases, this study represents a correct evaluation with respect to real health risks induced by orthodontic devices.

Mutagenicity and cytotoxicity assessment in patients undergoing orthodontic radiographs

OBJECTIVES The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from individuals following radiography. METHODS Lateral and frontal cephalometric X-ray and panoramic dental X-rays were taken of a total of 18 healthy patients (6 male and 12 female) referred for orthodontic therapy. Exfoliated oral mucosa cells were collected immediately before X-ray exposure and after 10 days. RESULTS The results revealed no statistically significant difference (P > 0.05) in the frequency micronucleated oral mucosa cells after X-ray exposure. However, X-ray was able to increase other nuclear alterations closely related to cytotoxicity, such as karyorrhexis, pyknosis and karyolysis. CONCLUSIONS Data indicated that exposure to certain radiography may not be a factor in inducing chromosomal damage, but it does promote cytotoxicity.

Radiopacifiers do not induce genetic damage in murine fibroblasts: an in vitro study.

AIM To evaluate whether several radiopacifiers are able to induce genetic damage in a laboratory cell culture study. METHODOLOGY Murine fibroblasts were exposed to barium sulphate, bismuth oxide or zirconium oxide, at final concentrations ranging from 10 to 1000 microg mL(-1) for 1 h at 37 degrees C. The negative control group was treated with a vehicle control [phosphate buffered solution (PBS)] for 1 h at 37 degrees C and the positive control group was treated with hydrogen peroxide (at 10 microM) for 5 min on ice. Genotoxicity data were assessed by the single-cell gel (comet) assay. RESULTS All the tested compounds did not induce DNA breakage as depicted by the mean tail moment in all the concentrations analysed. CONCLUSION Exposure to the tested radiopacifiers may not be a factor that increases the level of DNA lesions in mammalian cells as detected by a single-cell gel (comet) assay.

Biomonitoring of DNA damage and cytotoxicity in individuals exposed to cone beam computed tomography

OBJECTIVES The aim of the present study was to evaluate DNA damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated buccal mucosa cells from adults following cone beam CT exposure. METHODS A total of 19 healthy adults (10 men and 9 women) submitted to cone beam CT were included. RESULTS No significant statistically differences (P > 0.05) in micronucleus frequency were seen before and after cone beam CT exposure. In contrast, the tomography was able to increase other nuclear alterations closely related to cytotoxicity such as karyorrhexis, pyknosis and karyolysis (P < 0.05). CONCLUSION In summary, these data indicate that cone beam CT may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity.

Mutagenicity and cytotoxicity in patients submitted to ionizing radiation.

OBJECTIVES To evaluate and compare mutagenicity (micronucleus) and cytotoxicity (karyorrhexis, pyknosis, and karyolysis) in exfoliated buccal mucosa cells of children following cone beam computed tomography (CBCT) or conventional radiograph exposure necessary for orthodontic planning. MATERIALS AND METHODS A total of 49 healthy children were submitted to CBCT or a conventional orthodontic radiographic protocol; they were divided into two groups based on exam: CBCT (n  =  24) and Radiographic Set (n  =  25) groups. The micronucleus test in the exfoliated buccal mucosa cells was applied. RESULTS There was not a statistically significant difference (P > .05) found between the number of micronucleated buccal mucosa cells (MNC) before and after exposure to radiation in either group, showing that neither group experienced a mutagenic effect. However, radiation did cause other nuclear alterations closely related to cytotoxicity, including karyorrhexis, pyknosis, and karyolysis, in both groups (P < .05). The CBCT group presented a greater increase in cell death than was noted in the Radiographic Set group (P < .044). CONCLUSION According to the micronucleus test, mutagenicity was not induced by the CBCT or the conventional radiographs, but cytotoxicity was verified after these exams, especially after CBCT. That might have happened once the CBCT group received a greater radiation dose than the Radiographic Set group as a result of the protocols used in orthodontic planning for this study.

Cytogenetic biomonitoring in children submitting to a complete set of radiographs for orthodontic planning.

OBJECTIVES To evaluate the DNA damage (micronucleus) and cellular death (pyknosis, karyolysis, and karyorrhexis) in exfoliated buccal mucosa cells from children undergoing orthodontic radiographs. MATERIALS AND METHODS A total of 25 healthy children undergoing orthodontic therapy partook in a complete set of orthodontic radiographs (lateral cephalographic, posteroanterior cephalographic, panoramic, full periapical exam, and bitewing). The micronucleus test in the buccal exfoliated cells was applied. The paired-samples t-test and the Wilcoxon test were used to compare the frequencies of alterations before and after X-ray exposure. RESULTS We found no statistically significant differences (P > .05) between micronucleated buccal mucosa cells before and after exposure to radiation. However, radiation did cause other nuclear alterations closely related to cytotoxicity (P  =  .007). CONCLUSION According to the micronucleus test, the complete set of radiographs requested in the orthodontic planning may not be a factor that induces chromosomal damage, but it is able to promote cytotoxicity.

The influence of sleep deprivation and obesity on DNA damage in female Zucker rats

OBJECTIVE: The aim of this study was to evaluate overall genetic damage induced by total sleep deprivation in obese, female Zucker rats of differing ages. METHOD: Lean and obese Zucker rats at 3, 6, and 15 months old were randomly distributed into two groups for each age group: home-cage control and sleep-deprived (N = 5/group). The sleep-deprived groups were deprived sleep by gentle handling for 6 hours, whereas the home-cage control group was allowed to remain undisturbed in their home-cage. At the end of the sleep deprivation period, or after an equivalent amount of time for the home-cage control groups, the rats were brought to an adjacent room and decapitated. The blood, brain, and liver tissue were collected and stored individually to evaluate DNA damage. RESULTS: Significant genetic damage was observed only in 15-month-old rats. Genetic damage was present in the liver cells from sleep-deprived obese rats compared with lean rats in the same condition. Sleep deprivation was associated with genetic damage in brain cells regardless of obesity status. DNA damage was observed in the peripheral blood cells regardless of sleep condition or obesity status. CONCLUSION: Taken together, these results suggest that obesity was associated with genetic damage in liver cells, whereas sleep deprivation was associated with DNA damage in brain cells. These results also indicate that there is no synergistic effect of these noxious conditions on the overall level of genetic damage. In addition, the level of DNA damage was significantly higher in 15-month-old rats compared to younger rats.

Chromosome breakage and cellular death are induced in oral epithelial cells of hairdressers: a preliminary study

The aim of the present study was to comparatively evaluate genomic damage (micronucleus) and cellular death (pyknosis, karyolysis and karyorrhexis) in exfoliated oral mucosa cells from hairdressers using two different anatomic buccal sites: cheek mucosa and lateral border of the tongue. A total of 28 hairdressers and 30 health controls (non-exposed individuals) were included in this setting. Individuals had epithelial cells from the cheek and lateral border of the tongue mechanically exfoliated, placed in fixative and dropped in clean slides that were checked for the previously mentioned nuclear phenotypes. The results pointed out statistically significant differences (p < 0.05) of micronucleated oral mucosa cells from hairdressers in the lateral border of the tongue. Exposure to hair dyes caused an increase of other nuclear alterations closely related to cytotoxicity, such as karrhyorexis, pyknosis and karyolysis in both the oral sites evaluated. In summary, these data indicate that hairdressers are occupationally exposed to agents that are genotoxic and cytotoxic. It seems that the lateral border of the tongue is a more sensitive site to the genotoxic and cytotoxic effects of hair dyes.

OIP5 Expression Sensitize Glioblastoma Cells to Lomustine Treatment

Glioblastoma (GBM) is an incurable disease ranked among the deadliest solid cancers worldwide. A better understanding on the molecular aspects of this malignancy could contribute to the development of new treatment strategies and help to improve survival rates. Previously, our group had shown that GBM patients expressing the cancer/testis antigen Opa Interacting Protein 5 (OIP5) present a longer survival period than the OIP5-negative group. The main goal of this study was to evaluate the OIP5 contribution to GBM tumorigenesis and assess the role of OIP5 in GBM cell response to lomustine, an alkylating agent used in the treatment of this malignancy. So, the effect of OIP5 knockdown was evaluated in A172 and T98G GBM cell lines. Our results demonstrated that downregulation of the OIP5 stimulates glioma cell viability and inhibits cell death-induced necrosis prompted by lomustine. In conclusion, our data shows that OIP5 expression in GBM cells seems to be able to enhance lomustine cytotoxic effects, reinforcing that this gene is a potential therapeutic target and putative molecular biomarker for treatment response in GBM.