Chris Krebs Danilevicz

Influence of different energy densities of laser phototherapy on oral wound healing

Abstract. The aim of the present prospective study was to evaluate the impact of laser phototherapy (LPT) on the healing of oral ulcers. Different power densities were used on oral wounds in Wistar rats (n=72) randomly divided into three groups: control (0  J/cm2), 4  J/cm2 laser, and 20  J/cm2 laser. Ulcers (3 mm in diameter) were made on the dorsum of the tongue with a punch. Irradiation with an indium-gallium-aluminum-phosphide laser (660 nm; output power: 40 mW; spot size: 0.04  cm2) was performed once a day in close contact with the ulcer for 14 consecutive days. A statistically significant acceleration in healing time was found with wounds treated with 4  J/cm2 LPT. Moreover, striking differences were found in the ulcer area, healing percentage, degree of reepithelialization, and collagen deposition. The most significant changes occurred after 5 days of irradiation. Based on the conditions employed in the present study, LPT is capable of accelerating the oral mucosa wound-healing process. Moreover, faster and more organized reepithelialization and tissue healing of the oral mucosa were achieved with an energy density of 4  J/cm2 in comparison to 20  J/cm2.

Topical Aloe Vera (Aloe barbadensis Miller) Extract Does Not Accelerate the Oral Wound Healing in Rats

The effect of topical application of Aloe Vera (Aloe barbadensis Miller) extract was assessed on the healing of rat oral wounds in an in vivo model using 72 male Wistar rats divided into three groups (n = 24): control, placebo and Aloe Vera (0.5% extract hydroalcoholic). Traumatic ulcers were caused in the dorsum of the tongue using a 3‐mm punch tool. The Aloe Vera and placebo group received two daily applications. The animals were sacrificed after 1, 5, 10 and 14 days. Clinical analysis (ulcer area and percentage of repair) and histopathological analysis (degree of re‐epithelialization and inflammation) were performed. The comparison of the differences between scores based on group and experimental period, both in quantitative and semi‐quantitative analyses, was performed using the Kruskal–Wallis test. The significance level was 5%. On day 1, all groups showed predominantly acute inflammatory infiltrate. On day 5, there was partial epithelialization and chronic inflammatory infiltrate. On the days 10 and 14 total repair of ulcers was observed. There was no significant difference between groups in the repair of mouth ulcers. It is concluded that treatment using Aloe Vera as an herbal formulation did not accelerate oral wound healing in rats. Copyright

Nuclear changes in oral mucosa of alcoholics and crack cocaine users

The effects of drugs of abuse on oral mucosa are only partly understood. The aims of the present study were to: (1) evaluate the frequency of nuclear changes in normal-appearing oral mucosa of alcoholics and crack cocaine users and (2) assess their association with cell proliferation rate. Oral smears were obtained from the border of the tongue and floor of the mouth of 26 crack cocaine users (24 males and 2 females), 29 alcoholics (17 males and 12 females), and 35 controls (17 males and 18 females). Histological slides were submitted to Feulgen staining to assess the frequency of micronuclei (MN), binucleated cells (BN), broken eggs (BE), and karyorrhexis (KR). A significant increase in the frequency of MN was observed in cells exfoliated from the tongue of crack cocaine users (p = 0.01), and alcoholics showed a higher frequency of KR in cells obtained from the floor of the mouth (p = 0.01). Our findings suggest that the use of crack cocaine induces clastogenic effects, whereas alcoholism is associated with higher degrees of keratinization in the floor of the mouth.

Ameloblastic neoplasia spectrum: a cross-sectional study of MMPS expression and proliferative activity.

OBJECTIVE To compare the proliferation and the expression of matrix metalloproteinases (MMPs; MMP-2 and MMP-9) in solid and unicystic ameloblastomas with ameloblastic carcinomas. STUDY DESIGN Five cases of ameloblastic carcinoma (AC), 18 cases of solid ameloblastoma (SA), and seven of unicystic ameloblastoma (UA) were selected. The immunohistochemical expression of MMPs was assessed by the percentage of positive tumor cells and stained stroma. The mean argyrophilic nucleolar organizer region (AgNOR) and the percentage of cells with more than one AgNOR per nucleus were evaluated. RESULTS Statistically significant higher mean AgNOR was observed in AC than in SA and UA. MMP-2 was expressed similarly in tumor and stroma among groups. MMP-9 was higher in the stroma of SA than that of UA (P = .0484). CONCLUSIONS The cell proliferation was related to the greater aggressiveness of AC. High expression of MMP-2 and MMP-9 in all lesions highlighted the importance of these enzymes in the biology of ameloblastic tumors.

Drosophila melanogaster as a model for the study of Malassezia pachydermatis infections

Malassezia pachydermatis is a yeast that is commonly found in the skin of most animals. Changes in the physical, chemical or immunological processes of the skin may render the host more susceptible to the yeast, which then may cause otitis, dermatitis or, less often, systemic infection. We tested the pathogenicity of M. pachydermatis in wild-type (WT) and Toll-deficient Drosophila melanogaster. Flies were inoculated in the thorax with a needle previously dipped in inoculum concentrations ranging from 103 and 107 yeast cells/mL. After infection, flies were housed at 29 °C and mortality was evaluated daily until day seven. WT flies were resistant to the infection, whereas Toll-deficient flies showed inoculum-dependent mortality rates. Fungal burden, assessed by histopathological analysis and by counting the number of colony-forming units of dead flies, corroborated the results. The D. melanogaster model is a promising minihost model for future large-scale studies of virulence mechanisms and antifungal drug activity in malasseziosis.

Epithelial oral mucosal cells: Do they behave differently when exposed to oral carcinogens?

To assess the level of maturation and proliferation of epithelial cells and the correlation with immunocytochemical expression of adhesion (E‐cadherin) and cell differentiation (involucrin) markers.

Cell proliferation markers at the invasive tumor front of oral squamous cell carcinoma: comparative analysis in relation to clinicopathological parameters of patients

Abstract Objectives To evaluate the number of AgNORs per nucleus and the expression of Ki-67 at the tumor invasion front (TIF) in relation to clinical parameters (TNM), TIF classification and the prognosis of oral squamous cell carcinomas in an Uruguayan population. Material and Methods This study was conducted through a retrospective survey from 2000 to 2010 at the National Institute of Cancer Montevideo, Uruguay and included 40 patients. The samples were obtained from the resection of the tumor and the TIF was defined according with Bryne, et al.5 (1992). Expression of Ki-67 was assessed by the percentage of positive tumor cells and the AgNOR was recorded as the mean AgNOR (mAgNOR) and the percentage of AgNOR per nucleus (pAgNOR). All analyzes were performed by a blinded and calibrated observer. Results No statistically significant association was observed between immunostaining of Ki-67 and AgNOR with the different types of TIF, regional metastasis and patients prognosis, however it was observed an increase in Ki-67 expression associated with worse patient’s clinical staging, although not statistically significant. Conclusions Our results suggest that proliferation markers as AgNOR and Ki-67 are not prognostic markers at the tumor invasive front of carcinoma of oral squamous cell.

Location of injected polymethylmethacrylate microspheres influences the onset of late adverse effects : an experimental and histopathologic study

Polymethylmethacrylate (PMMA) has been widely used in the correction of wrinkles because of its long-lasting cosmetic improvements. However, side effects and complications may occur, and its clinical appearance on the oral mucosa can be similar to that of inflammatory or neoplastic disease. The aim of this research was to compare the clinical and histopathologic responses to PMMA injected by two different methods. Twenty-two rats received an injection of PMMA using the tunneling technique (gold standard), with subcutaneous deposition of the filler in the face, or a variation of the technique with transcutaneous submucosal deposition of the filler in the cheek. The tissue reaction was analyzed clinically every 24 hours during the first week, then once a week for the following 3 months. Histologic evaluation was based on the local inflammatory response to the filler. No clinical changes were observed during the initial evaluation period (0–14 days). After 14 days, only the submucosal group showed extra-oral enlargement (n=4, 18.2%). Histopathologic analysis revealed nodule formation in four animals (18.2%) in the submucosal group, with no nodules observed in the subcutaneous group. The data obtained in this study demonstrate that the technique used to deliver the filler may influence the risk of adverse reactions.