S. Sousa

Characterization of the cellular component of polymorphous low-grade adenocarcinoma by immunohistochemistry and electron microscopy

In order to characterize the cellular component of the polymorphous low-grade adenocarcinoma (PLGA) of the salivary gland, a morphological and immunohistochemical study was carried out. Thirty cases of PLGA were studied by light microscopy and immunohistochemistry and five cases by transmission electron microscopy (TEM). The expression of cytokeratins (CKs) 7,8,10,13,14,18,19, vimentin and muscle-specific actin (MSA) was investigated through the streptavidin-biotin method. The majority of tumor cells stained for vimentin, CKs 8, 18 and 7. CK 14 was positive in most cells of the papillary and trabecular sub-types. Although the expression of CKs 8,18 and 14 varied among the tumors sub-types, a straight relationship between each histologic pattern and the CK expression could not be delineated. MSA was reactive in only three tumors while CKs 10 and 13 were not detected in any tumor studied. The absence of MSA and the expression of CKs 8,18 and 7, in most of the tumor cells, lead to the hypothesis that myoepithelial cells are not the major cellular component of the PLGA. TEM revealed cells exhibiting microvilli and variable amounts of secretory granules, some of them suggesting an excretory activity. The presence of CKs 8,18 and 7, added to the secretory granules, indicates that PLGA originates from cells located at the acinar-intercalated duct junction.

The severity of epithelial dysplasia is associated with loss of maspin expression in actinic cheilitis

Background:u2002 Prolonged exposure of the lip to sunlight may cause actinic cheilitis (AC) and squamous cell carcinoma (SCC). Maspin is a serpin with tumor suppressor functions. This work analyzed the presence and distribution of maspin in AC and lip SCC.

Immunohistochemical expression of Rho GTPases in ameloblastomas.

Rho GTPases are proteins that regulate cell cycle, shape, polarization, invasion, migration, and apoptosis, which are important characteristics of normal and neoplastic cells. Rho GTPases expression has been reported in normal tooth germ and several pathologies; however, it has not been evaluated in ameloblastomas. The aim of this study was to analyze the expression and distribution of RhoA, RhoB, Rac1, and Cdc42 Rho GTPases in solid and unicystic ameloblastomas. Three-micrometer sections from paraffin-embedded specimens were evaluated by using an avidin-biotin immunohistochemical method with antibodies against the proteins mentioned above. RhoA and RhoB staining was observed in a high number of cells (P < 0.05) and greater intensity in non-polarized ones. Rac1 was not observed, and Cdc42 did not show any statistical differences between the number of non-polarized and basal positive cells (P > 0.05). Upon comparing the studied ameloblastomas, a higher number of positive cells in the unicystic variant was observed than that in the solid one (P < 0,05). The results obtained suggest that these GTPases could play a role in the ameloblastoma neoplastic epithelial cell phenotype determination (polarized or non-polarized), as well as in variant (solid or unicystic) and subtype (follicular or plexiform) determination. Furthermore, they could participate in solid ameloblastoma invasion mechanisms.

Apurinic/apyrimidinic endonuclease 1 (APE1) is overexpressed in malignant transformation of salivary gland pleomorphic adenoma

DNA repair systems play a critical role in protecting the human genome against cumulative damage. The apurinic/apyrimidinic endonuclease 1 is a protein involved in DNA base excision repair and its expression still needs to be investigated in salivary gland tumors. The objective of this study is to analyze the immunoexpression of apurinic/apyrimidinic endonuclease 1 in pleomorphic adenomas and carcinomas ex pleomorphic adenomas of the salivary glands. A total of 33 pleomorphic adenomas and 16 carcinomas ex pleomorphic adenomas of the salivary glands underwent immunohistochemical study by the polymeric biotin-free technique. Immunopositive cells were analyzed quantitatively. For statistical analysis, Mann–Whitney test was performed and a significance level was set at pxa0≤xa00.05. All analyzed tumors (nxa0=xa049) were positive for apurinic/apyrimidinic endonuclease 1. However, there was a higher median expression in carcinomas ex pleomorphic adenomas (pxa0<xa00.001). There was no difference between this protein immunoexpression and tumors of major or minor salivary gland. Overexpression was found mainly in cases of carcinomas ex pleomorphic adenomas with lymph node metastasis (pxa0=xa00.002) and invasive growth (pxa0=xa00.003), when compared to cases without metastasis and without capsular invasion (intracapsular pattern). Our findings revealed that apurinic/apyrimidinic endonuclease 1 is downregulated in pleomorphic adenomas and overexpressed in carcinomas ex pleomorphic adenomas, suggesting that this protein is possibly deregulated in pleomorphic adenoma malignant transformation. Furthermore, the increased expression of this protein is associated with a more aggressive behavior in carcinomas ex pleomorphic adenomas, which suggests that this protein may represent a prognostic biomarker in the studied salivary gland tumors.

Evaluación del Efecto del Plasma Rico en Plaquetas en la Cicatrización de Heridas Alveolares en Ratas

Opinions about the clinical utility of platelet-rich plasma (PRP) vary, as a large number of experimental studies have questioned its efficacy. The purpose of this study was to evaluate the effects of PRP on experimental alveolar wound heali ng in rats. Fifty young adult male Wistar rats were divided in control and PRP groups and submitted to extraction of the right maxillary in cisor. In the PRP group, blood was collected by cardiac puncture, and the socket was filled with a PRP gel. Animals were euthanized after 1, 3, 7, 14 and 30 days. Histological and histomorphometric analyses were performed at each experimental time point. Semiquantitative hi stological analysis showed that the PRP group exhibited significantly more collagen-matrix deposition and less bone-matrix formation in th e socket than did the control group from 7 to 30 days. Histomorphometric analyses showed that the PRP group also exhibited lower bonetissue areas than the control group at 7 (p=0.0250) and 14 days (p<0.0001), but at 30 days, no significant difference between t he groups was observed. In the present study, PRP did not enhance alveolar wound healing, and PRP-treated rats exhibited low rates of bon e deposition during the intermediate phases of alveolar socket repair.

Oral neoplasms in domestic animals

nuclear enlargement, multinucleated epithelial cells, scattered abnormal mitoses, and dyskeratotic cells. There was no evidence of connective tissue invasion. The presence of HPV was confirmed by testing for group-specific antigen. Viral typing by polymerase chain reaction followed by restriction analysis and sequencing revealed the presence of HPV type 32. Therapy consisted of intralesional and subcutaneous interferoninjections. After approximately 21⁄2 months of treatment, the lesions had decreased in size but had not completely resolved.