Biomedical subjects

Tarcília Aparecida Silva

Publications and source records attributed to Tarcília Aparecida Silva.

5 recordsLinked to original sources

PubMed2006

Decrease in mast cells in oral squamous cell carcinoma: possible failure in the migration of these cells.

It is becoming accepted that multiple cell types in stromal microenvironment are involved in tumorigenesis. In this setting, mast cells (MC) display a diversity of roles that may contribute to the defense against tumors or tumor progression. Thus, the aim of this study was to evaluate density and migration of MCs in OSCC (oral squamous cell carcinoma) and pre-malignant oral hyperkeratosis (leukoplakia) as well as their relationship with clinical and microscopic parameters. The tryptase and c-kit expression was analyzed in 38 cases of OSCC, 26 cases of leukoplakia, and 12 cases of clinically healthy oral mucosa (control) by means of immunohistochemistry. The tryptase(+) cell numbers were decreased in OSCC (P=0.0003) and leukoplakia (P=0.03) compared with control. Similar numbers of tryptase(+) cells were observed in leukoplakia and OSCC (P=0.31). The density of c-kit(+) MCs was also significantly lower in OSCC and leukoplakia in relation to control resulting in a reduced c-kit(+)/tryptase(+) relationship in OSCC (19%) in comparison with leukoplakia (59%) and control (63%). No correlation was observed between MC populations with clinical and microscopic characteristics of OSCC. Our findings suggest that the decrease in MC numbers in pre-malignant and malignant oral lesions may be related to the migration failure of these cells, possibly reflecting an important modification in the microenvironment during tumor initiation and progression.

Adult↗

PubMed2003

Green teeth associated with cholestasis caused by sepsis: a case report and review of the literature.

Green stain is an uncommon condition associated with deposition of bilirubin in dental hard tissues. Prolonged hyperbilirubinemia has long been recognized as a frequent clinical manifestation of infection in the newborn, although the green staining of teeth caused by cholestasis associated with sepsis has not yet been reported. The purpose of this report is to present a case of green teeth of the primary dentition in a 3-year-old Brazilian girl. In addition, previously reported cases and their associated medical histories are analyzed.

Candidiasis↗

PubMed2003

Paradental cyst mimicking a radicular cyst on the adjacent tooth: case report and review of terminology.

A distinctive form of paradental cyst can occur on the buccal and apical aspects of erupted mandibular molars. This cyst has peculiar clinical and radiographic features, although the microscopic findings are the same as those of odontogenic inflammatory cysts. Diagnostic and therapeutic problems can occur when this lesion is misinterpreted as a radicular cyst. The purpose of this paper is to present an additional case of a paradental cyst in the buccal and mesial aspects of a mandibular second molar involving the apical area of a mandibular first molar. The difficulty of diagnosis, treatment, and controversies regarding terminology are also discussed.

Adolescent↗

PubMedDate not supplied

In vitro activation of the hemolysin in Prevotella nigrescens ATCC 33563 and Prevotella intermedia ATCC 25611.

Hemolytic activity was evaluated in the putative periodontopathogens Prevotella intermedia and Prevotella nigrescens. Whole cells of both species present weak hemolytic activity evidenced only by solid media assays after 48 h of bacterial growth or after 5 h of interaction with erythrocytes at 37 degrees C in liquid assays. In this work we show that the use of crude extract allowed the detection of a higher hemolytic activity for P. intermedia, but surprisingly not for P. nigrescens. Incubation at 37 degrees C for 9 h, or treatment with trypsin or proteinase K, increased or exposed the hemolytic activity of P. intermedia and P. nigrescens crude extract, respectively. The activation process was inhibited by TLCK and PMSF but not by EDTA, E-64 or pepstatin A, indicating the serino-protease nature of the factor involved in activation of P. intermedia and P. nigrescens hemolysins. Both the buffer and the pH employed for cell fractionation influenced the activation of hemolysin, and the best results were obtained with Universal buffer at pH 8.0. The activated hemolysins acted optimally at pH 6.5 at 37 degrees C and the maximum hemolytic activity was detected at the early log phase of growth. The results of this study show for the first time a strong hemolytic activity for P. nigrescens and evidence of proteolytic activation of hemolysins produced by periodontopathogens.

Animals↗

PubMedDate not supplied

Hemolytic activity of Prevotella intermedia and Prevotella nigrescens strains: influence of abiotic factors in solid and liquid assays.

The influence of growth medium, hemin and menadione, blood source and atmosphere of incubation on the expression of hemolytic activity of 25 strains of Prevotella intermedia and Prevotella nigrescens was evaluated. The best hemolytic activity was observed for samples of both species growing in brain heart infusion agar and incubated in Brewer-like anaerobic jars for 48 h. Hemolysis was less intense and occurred later in the presence of hemin and menadione in solid media. beta-Hemolysis was detected for medium supplemented with horse or human blood and alpha-hemolysis was observed when sheep blood was used. These results suggesting some specificity for the hemolytic activity were also observed in liquid assays in which sheep erythrocytes were found to be resistant to hemolysis while horse and human cells where lysed. In liquid assays, the hemolytic activity of all studied strains remained stable in the pH range of 6.0 to 8.5 and was not altered by iron-scavenging compounds or atmosphere of incubation. The phenomenon of hot/cold hemolysis was ruled out as the mechanism of action of P. intermedia and P. nigrescens hemolysin.

Animals↗