Marco Antônio Dias da Silva

Matrix metalloproteinase gene polymorphisms and oral cancer.

Since oral squamous cell carcinoma (OSCC) is the most prevalent malignant cancer in the oral cavity, several researches have been performed to study the role of important enzymes in this disease. Among them, the matrix metalloproteinases (MMPs) are highlighted, due to the fact that they are proteinases responsible to degrade many extra-cellular matrix components, making possible the invasion of neoplasic cells. Important tools in cancer prognosis have been utilized aiming to correlate high levels of MMPs and OSCC, such as immunohistochemical, zymographic and mRNA detection methods. However, these techniques are usually applied after cancer detection, characterizing a curative but not a preventive medicine. Trying to make interventions before the development of the disease and making possible the identification of people at high risk and, analysis of modifications in MMP genes has been a chance for modern medicine. Recently, polymorphisms in MMP genes have been related to different neoplasias, including OSCC. Despite investigation is beginning, MMP gene polymorphisms seems to have a promising future in oral cancer research and some of the present results have shown that there are MMP polymorphisms related to an increased risk for developing oral cancer. Key words:Oral cancer, polymorphism, matrix metalloproteinase.

Effects of simultaneous nicotine and alcohol use in periodontitis progression in rats: A histomorphometric study.

Objective: The aim of this study was to evaluate the effects of alcohol and nicotine, when used alone or simultaneously, on the alveolar bone loss area resulting from ligature-induced periodontitis in rats. Study design: Forty adult male rats received a cotton ligature in the first lower molar sulcular area, and the animals were randomly assigned to different treatments (n = 10, each group) including daily peritoneal injections of saline solution (group A), submitted to self-administration of alcohol 25% (group B), nicotine solution in concentration 0.19 μl/ml (group C), and nicotine solution in concentration 0.19 μl/ml plus self-administration of alcohol 25% (group D). Five weeks later, the animals were sacrificed, and the samples were routinely processed for semi-serial decalcified sections. Results: Ligated teeth showed more alveolar bone loss than unligated ones (p < 0.05). Unligated teeth showed no significant differences between each other (p > 0.05). Analyses between the ligated teeth showed that the group C (nicotine) or group B (alcohol 25%) each had increasing alveolar bone loss in the furcation area, and the simultaneous combination alcohol and nicotine (group D) intensified these effects (p < 0.05). Conclusion: The results suggest that the simultaneous combination of alcohol and nicotine have a synergistic effect in the progression of periodontitis, evidenced by increased furcation region bone destruction in periodontal disease in rats. Key words:Alveolar bone loss, periodontitis, nicotine, alcohol, rats.

Intermittent administration of parathyroid hormone improves the repairing process of rat calvaria defects: A histomorphometric and radiodensitometric study

Background The aim of this study was to evaluate the effects of intermittent treatment of parathyroid hormone (PTH (1-34)) on the bone regeneration of critically-sized rat calvarial bone defects. Material and Methods Thirty-two male rats were trephined (4mm fullthickness diameter), in the central part of the parietal bones and divided into 2 groups of 16. The PTH group received subcutaneous injections of PTH (1-34) at 40µg/kg, 3 times a week and the control (CTL) group received the vehicle in the same regimen. The rats were sacrificed at 4 weeks post-treatment regimen, the parietal bones were extracted and samples were evaluated through histomorphometry and radiodensitometry. Results The histological observations showed that the PTH group presented more “island-like” new bone between the defect margins with fibrous tissues than did the CTL group. The PTH group significantly exhibited greater histologic bone formation than did the CTL group (1.5mm ±0.7; 1.9 mm ± 0.6, p<0.05/ for residual bone defect). The radiodensitometry analysis revealed significant differences among the PTH and CTL groups (2.1 Al eq. ±0.04; 1.8Al eq. ±0.06, p<0.05), demonstrating an increase in bone mineral density. The PTH treatment contributed to the bone formation with a higher amount of mineral and/or fibrous tissue when compared with the CTL group. Conclusions The results suggest that it was possible to increase the process of bone regeneration by accelerating the healing process in rat calvarial defects through intermittent administration of the PTH treatment. Key words: Bone, skull, rats, bone regeneration, bone density.

O uso das TIC no ensino da morfologia nos cursos de saúde do Rio Grande do Norte

Forms of acquiring knowledge have been changed by the increased use of Information and Communications Technology. Easy access to online content, which is not always reliable, allied to the profile of new students has led to a belief that the education system may require changes. The aim of this study was therefore to evaluate the profile of ICT use in morphology studies in Rio Grande do Norte health courses. The National Institute of Educational Studies and Research (INEP) database of higher education courses was used as the source for reviewing the existence of internet pages for the courses and subjects and the form of ICT use. It was found that, in April 2012, 69% of the courses had a website, which percentage had fallen to 59% by October of the same year. In terms of the institutions, 50% of the public universities had a page for their courses, against 75% of the private universities. Furthermore, none of the universities had any internet pages offering morphology content linked to the course website. In conclusion, ICT is being underused by health courses in Rio Grande do Norte state.

Parathyroid hormone intermittent administration promotes delay on rat incisor eruption

OBJECTIVE This study evaluated the influence of parathyroid hormone (PTH) (1-34) intermittent administration on rat eruption rates of lower incisors under normo, hyper and hypofunctional conditions, Sharpey fibers insertion, and alveolar bone formation. MATERIALS AND METHODS Wistar male rats received PTH (1-34) three times a week during the entire experimental period, 31days. Control animals received the same concentration of the vehicle solution during the same period. Three injections of alizarin were also performed. The experiment evaluated the eruptive rate, the alveolar bone formation and also the morphology, and the area density of Sharpey fibers. After the sacrifice, the mandibles were dissected and samples were prepared for fluorescence and scanning electron microscopy observations. RESULTS PTH-treated animals showed significantly reduced eruption rates in all different functional conditions. Analysis evidenced that PTH-treated rats present an increase in bone formation and area density of the Sharpey fibers. CONCLUSION We concluded that the PTH (1-34) intermittent administration reduced the eruptive process rates, through bone formation enhancement and increase in the area density of Sharpey fibers.