Kallikrein 4 and matrix metalloproteinase-20 immunoexpression in malignant, benign and infiltrative odontogenic tumors.

CONTEXT: Matrix metalloproteinase-20 (MMP20) (enamelysin) and kallikrein 4 (KLK4) are enzymes secreted by ameloblasts that play an important role in enamel matrix degradation during amelogenesis. However, studies have shown that neoplastic cells can produce such enzymes, which may affect the tumor infiltrative and metastatic behaviors. AIMS: The aim of this study is to assess the biological role of MMP20 and KLK4 in odontogenic tumors. MATERIALS AND METHODS: The enzymes were analyzed immunohistochemically in ameloblastoma, adenomatoid odontogenic tumor (AOT), calcifying epithelial odontogenic tumor, keratocystic odontogenic tumor with or without recurrence and odontogenic carcinoma. STATISTICAL ANALYSIS USED: Clinicopathological parameters were statistically correlated with protein expression using the Fisher's exact test. Kruskal-Wallis and Wilcoxon-independent methods were used to evaluate the differences in median values. RESULTS: Positive Immunoexpression was detected in all benign lesions, with a prevalence of 75-100% immunolabeled cells. Patients were predominantly young, Caucasian, female, with slow-growing tumors located in the mandible causing asymptomatic swelling. No KLK4 expression was seen in carcinomas, and the amount of MMP20-positive cells varied between 20% and 80%. Rapid evolution, recurrence and age >60 years characterized the malignant nature of these lesions. CONCLUSIONS: Data showed that KLK4 and MMP20 enzymes may not be crucial to tumoral infiltrative capacity, especially in malignant tumors, considering the diversity and peculiarity of these lesions. The significant immunoexpression in benign lesions, remarkably in AOT, is likely associated with differentiated tumor cells that can produce and degrade enamel matrix-like substances. This would be expected since the histogenesis of odontogenic tumors commonly comes from epithelium that recently performed a secretory activity in tooth formation.

Histological analysis of the biocompatibility of calcium hydroxide associated with a new vehicle.

BACKGROUND: Several substances have been researched to act as vehicles associated with calcium hydroxide. The specific type of vehicle is directly related to the effectiveness of the ionic dissociation, antimicrobial action, and biocompatibility of this medication. AIM: To make a histological evaluation of the biocompatibility of calcium hydroxide associated with a new vehicle (triethanolamine), compared with polyethylene glycol, saline solution, and olive oil. MATERIALS AND METHODS: Fifty mice of guinea pig species were randomly divided into five groups (n = 10) according to each vehicle used--Group 1: calcium hydroxide, Group 2: triethanolamine, Group 3: polyethylene glycol, Group 4: saline solution, and Group 5: olive oil--and further divided into subgroups according to the two analysis periods--(a) 30 and (b) 90 days. Teflon carriers filled with the evaluated substances were placed in standardized bone cavities in the anterior mandible region. The animals were euthanized to perform a histological analysis after the time periods analyzed. RESULTS: In 30 days, specimens from Groups 1, 3, and 5 showed a very pronounced inflammatory response. Specimens from Group 2 showed an inflammatory reaction ranging from mild to severe, with rapid resorption of the material and progressive advancement of osteoid tissue into the teflon carriers. Specimens from Group 4 showed a moderate inflammatory reaction. In 90 days, specimens from Group 1 showed a very pronounced fibrous replacement. In regard to Group 2 specimens, the tested material was solubilized and replaced by newly formed bone tissue. For Groups 3 and 5 specimens, the inflammatory reaction went from acute to moderate. In relation to Group 4 specimens, an organized bone formation process was observed. CONCLUSIONS: Specimens from Group 2 showed higher biocompatibility, especially as compared with the specimens from Groups 3 and 5.

Distinct Th1, Th2 and Treg cytokines balance in chronic periapical granulomas and radicular cysts.

BACKGROUND: Periapical lesions are a host response that involves immune reaction to prevent dissemination of bacteria from an infected root canal. The purpose of this study was to evaluate the levels of nitric oxide (NO), IL-4, TGF-beta, tumor necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) in chronic periapical lesions and to determine their possible association with clinical and radiographic parameters. METHODS: Seventeen human radicular cysts and 30 periapical granulomas were used in this study. Cytokines and NO were assessed by enzyme-linked immunosorbent assay and by the Griess reaction respectively confirmed by immunohistochemical. RESULTS: TNF-alpha and IFN-gamma were detected in 10% of granulomas and in 41.2% and 70% of radicular cysts. IL-4 was reactive in 24% of cysts, and TGF-beta was positive in all samples. Patients with tenderness showed significantly higher levels of IFN-gamma and IL-4 (P < 0.05). Swelling was associated with high levels of TNF-alpha, IFN-gamma, and IL-4 (P < 0.05). Lesions presenting bone resorption were associated with high levels of NO (P < 0.05). CONCLUSIONS: Periapical granulomas display a regulatory environment characterized by high TGF-beta and low inflammatory cytokine levels, while radicular cysts has mist Th1 and Th2 inflammatory reaction with the presence of IFN-gamma, TNF-alpha, and IL-4.

Toxoplasma gondii infection reveals a novel regulatory role for galectin-3 in the interface of innate and adaptive immunity.

In attempts to investigate the role of galectin-3 in innate immunity, we studied galectin-3-deficient (gal3-/-) mice with regard to their response to Toxoplasma gondii infection, which is characterized by inflammation in affected organs, Th-1-polarized immune response, and accumulation of cysts in the central nervous system. In wild-type (gal3+/+) mice, infected orally, galectin-3 was highly expressed in the leukocytes infiltrating the intestines, liver, lungs, and brain. Compared with gal3+/+, infected gal3-/- mice developed reduced inflammatory response in all of these organs but the lungs. Brain of gal3-/- mice displayed a significantly reduced number of infiltrating monocytes/macrophages and CD8+ cells and a higher parasite burden. Furthermore, gal3-/- mice mounted a higher Th1-polarized response and had comparable survival rates on peroral T. gondii infection, even though they were more susceptible to intraperitoneal infection. Interestingly, splenic cells and purified CD11c+ dendritic cells from gal3-/- mice produced higher amounts of interleukin-12 than cells from gal3+/+ mice, possibly explaining the higher Th1 response verified in the gal3-/- mice. We conclude that galectin-3 exerts an important role in innate immunity, including not only a pro-inflammatory effect but also a regulatory role on dendritic cells, capable of interfering in the adaptive immune response.

Miíases em humanos na região de Uberlândia, Minas Gerais, Brasil / Human been myiasis in the Uberlandia region, state of Minas Gerais, Brazil

A partir de uma análise retrospectiva, são descritos aspectos epidemiológicos de miíases humanas diagnosticadas no período de janeiro 1986 a fevereiro de 1997 em um hospital escola de Uberlândia, Estado de Minas Gerais. Foram analisados 431 prontuários médicos e incluídos no estudo 222 casos de miíases (51,5 por cento), cujos atendimentos foram feitos no ambulatório (51,5 por cento) e no pronto socorro (40,1 por cento). As miíases ocorreram mais frequentemente em pacientes do sexo masculino (64 por cento). As miíases em crianças e adultos jovens até um, cinco e vinte anos representaram respectivamente 11,7 por cento, 30,1 por cento e 53,1 por cento dos casos. Em 66 (29,7 por cento) prontuários, os diagnósticos indicaram miíase remanescentes. O número de casos de miíases aumentou no período de outubro a abril (período mais quente e úmido do ano em Uberlândia). São discutidos aspectos físicos, econômicos, sociais e culturais que parecem estar associados a miíases humanas em Uberlândia.