Lucas Novaes Teixeira

Establishment of a primary culture of polymorphous low grade adenocarcinoma cells

OBJECTIVEnThe aim of the present study was to establish a primary cell culture derived from polymorphous low grade adenocarcinoma (PLGA).nnnDESIGNnThe neoplastic cells were derived from a 57-year-old female patient diagnosed with PLGA. A fragment of the tumor was collected and submitted to enzymatic digestion followed by centrifugation on a Percoll gradient. The cell population was characterized by means of immunofluorescence and detection of PRKD1 gene mutations.nnnRESULTSnEpifluorescence analysis of the primary culture revealed that the malignant epithelial cells were predominantly polygonal in shape and positive for cytokeratin 7, vimentin, and S100. The doubling time of the cell culture was 86.73h. The restriction digestion assay showed that the neoplastic cells possess PRKD1 gene mutations.nnnCONCLUSIONnThe establishment of primary cell culture derived from PLGA should be considered a useful tool for molecular analysis of this salivary gland tumor.

Simvastatin modulates gingival cytokine and MMP production in a rat model of ligature-induced periodontitis

Purpose The aim of this study was to evaluate the effect of simvastatin on the synthesis of cytokines TNF-α and IL-10 and metalloproteinase (MMPs) 2 and 9 in a rat model of ligature-induced periodontitis. Materials and methods Twenty Wistar rats were used, and a cotton ligature was place in a subgingival position encircling the entire cervix of the first molar of the left (ipsilateral) side of the mandible. The right (contralateral) side of the mandible had no ligature placed and was used as control. After the ligature placement, animals were randomly assigned to two experimental groups (n=10): 1) rats with ligature + vehicle (saline; 10 mL/kg; orally) and 2) rats with ligature + simvastatin (25 mg/kg; orally). After 14 days of treatment, the animals were euthanized by anesthetic overdose and the gingival tissue was removed and homogenized in appropriate buffer. MMP-2 and -9 release as well as the IL-10 and TNF-α levels were detected by enzyme-linked immunosorbent assay. Statistical comparison was performed by unpaired Student’s t-test, with p<0.05 representing significance. Results No differences were observed for TNF-α production between the groups (p>0.05). However, IL-10 was upregulated in simvastatin-treated animals (1.8-fold increase) in comparison with the vehicle-treated group (p<0.05). Simvastatin reduced the gingival levels of MMP-9 (64.3%) in comparison with vehicle-treated samples (p<0.05). Conclusion Oral treatment with simvastatin increased the release of IL-10 and reduced the MMP-9 in ligature-induced periodontitis model in rats.

Leveraging Optimization Methods for Dynamically Assisted Control-Flow Integrity Mechanisms

Dynamic Binary Modification (DBM) tools are useful for cross-platform execution of binaries and are powerful run time environments that allow execution optimizations, instrumentation and profiling. These tools have also been used as enablers for control-flow integrity verification, a process that consists in the observation and analysis of a programs execution path focusing on the detection of anomalies, such as those arising from flow corruption based software attacks. Even though this class of tools helps us in identifying a myriad of attacks, it is typically expensive at run time and introduce significant overhead to the program execution. Considering their inherent high cost, further expanding the capabilities of such tools for detection of program flow anomalies can slow down the analysis to the point that it is unfeasible to run it in real world workflows. In this paper we present a mechanism for including program flow verification in DBMs that uses asynchronous analysis and applies different parallel-programming techniques that leverage current multi-core systems to control the overhead of our analysis. Our mechanism was tested against synthetic program flow corruption use cases and correctly detected all detours. With our new optimizations, we show that our system achieves an slowdown of only 1.46x, while a naively implemented verification system face 4.22x of overhead.

Effects of caffeic acid phenethyl ester application on dentin MMP-2, stability of bond strength and failure mode of total-etch and self-etch adhesive systems

OBJECTIVEnInvestigate the long-term effect of dentin pretreatment with 0.05 or 0.1% caffeic acid phenethyl ester (CAPE) on (1) bond strength of resin composite to dentin by a three-step etch-and-rinse (Adper Scotchbond Multipurpose/ ASB) or a two-step self-etch adhesive system (Clearfil SE Bond/ CSE), (2) their fracture mode, (3) the micromorphological features of the hybrid layer formed; and (4) the level of MMP-2 in dentin (after application, using a correlative immunoexpression/quantification approach).nnnDESIGNnComposite resin blocks were fabricated on 48 third molars (nu202f=u202f6), according to the type of adhesive and treatment (control, CAPE 0.05% and CAPE 0.1%). Slices were obtained for scanning electron microscopy (SEM) evaluation, and sticks were fabricated for microtensile tests (24u202fh and 1u202fyear). Aliquots of dentin powder were distributed (nu202f=u202f12) according to the treatment and the MMP-2 concentration was determined by ELISA.nnnRESULTSnTukey test showed that ASB groups presented higher BS in 24u202fh than CSE groups. ASB presented a reduction in BS values after 1-year. ASB and CSE presented no significant differences in BS after 1-year. CAPE had no effect on BS for both adhesive systems. The predominant failure mode for the ASB groups were adhesive; when 0.1% CAPE was applied there was a predominance of mixed fractures. Regarding the CSE group, 0.05% CAPE led to more adhesive failures, and the 0.1% concentration resulted in a higher number of cohesive failures in dentin. Higher MMP-2 concentrations were detected for the groups that did not undergo demineralization treatment, and the lowest values for the ASB groups treated with CAPE. SEM analysis showed no influence of pretreatment with CAPE.nnnCONCLUSIONSnCAPE did not influence the BS of the adhesives tested, or the micromorphology of the hybrid layer, irrespective of concentration or storage time. CAPE affected the fracture pattern at 24u202fh, depending on the concentration and the adhesive system used. Immunoassay analysis showed that CAPE 0.1% reduced the MMP-2 concentration in the ASB adhesive without affecting bond strength to dentin.

Effect of epithelial growth factor on matrix metalloproteinase‑2 and E‑cadherin/β‑catenin expression in an in situ model of tumorigenesis

The aim of the present study was to analyze the in vitro effect of various doses of epidermal growth factor (EGF; 5 and 10 ng/ml) on matrix metalloproteinase-2 (MMP-2) secretion and E-cadherin/β-catenin expression by co-cultured cells that mimic an in situ carcinoma ex-pleomorphic adenoma, where benign myoepithelial cells from a pleomorphic adenoma surround malignant epithelial cells. EGF was supplemented in various doses and the effects were evaluated following four days of cell culture. ELISA was performed to determine MMP-2 secretion levels. Gene expression for E-cadherin and β-catenin was analyzed using quantitative polymerase chain reaction. The results revealed that E-cadherin expression decreased when the cells were supplemented with 5 ng/ml EGF. ELISA results indicated that MMP-2 secretion increased when EGF was supplemented at concentrations of 5 and 10 ng/ml. The present findings demonstrated that EGF may be involved in the epithelial-mesenchymal transition process via altering the E-cadherin/β-catenin complex and increasing MMP-2 secretion, which may then favor the dissolution of the basement membrane to the benefit of malignant cell clusters, contributing to the development of an invasive phenotype in this in vitro model of tumorigenesis.

Mucoepidermoid Carcinoma of the Palatine Tonsil.

Mucoepidermoid carcinoma (MEC) is the most common primary salivary gland malignancy in both adults and children. It has a slight female predilection and usually presents as a painless, rubber-like or soft mass, which may be fixed or mobile. Histologically, MEC is comprised of a mixture of cell types including mucous, epidermoid, and intermediate cells that can be arranged in solid nests or cystic structures. In the oral cavity, it most frequently occurs at the palate or buccal mucosa. The present paper aimed to describe an unusual case of MEC arising in the palatine tonsil.