Márcia Martins Marques Jaeger

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.

Verruciform xanthoma of the oral mucosa. Report of four cases and a review of the literature

We present four new cases of verruciform xanthoma (VX) in the oral mucosa and review the literature. Clinical, histological, and immunohistochemical features of four new cases of VX were analysed together with cases found in a review of the literature. Expression of CD-68 was studied by immunohistochemistry. Only 162 cases were reported in the oral mucosa. Ninety were males (55.5%) and 72 were females (44.5%). Mean age was 44.9 years. The majority of cases occurred in masticatory mucosa (69.7%). Our cases exhibited papillary or verrucous proliferation of squamous epithelium associated with hyperparakeratosis and with numerous foamy cells confined to the lamina propria papillae. Foamy cells were positive to CD-68 antibody, showing a macrophagic nature. VX is a rare benign lesion, and is probably inflammatory. However, its aetiology and pathological mechanisms remain unknown.

Effect of spatial arrangement of the basement membrane on cultured pleomorphic adenoma cells. Study by immunocytochemistry and electron and confocal microscopy

Abstractu2002In a cell line from human pleomorphic adenoma (AP2 cells) we studied the response of these cells to basement membrane proteins. The culture was characterized as myoepithelial-like by transmission electron microscopy and immunocytochemistry. AP2 cells were grown in contact with a reconstituted basement membrane (Matrigel). Cells grown on Matrigel showed conspicuous phenotypic alterations, depending on how the substrate was applied. Cells grown on the top of Matrigel developed a dendritic phenotype, exhibiting thin, long and intercommunicating cytoplasmic extensions resembling normal myoepithelial cells. Cells grown inside Matrigel formed multi-layered clusters. Light, confocal and transmission electron microscopy showed that these clusters were formed by double-layered epithelioid cells delimiting luminal spaces. The cells facing the lumen were cuboidal, showing microvilli at the apical plasmalemmal and junctional complexes. The spatial arrangement of basement membrane is a key modulator of morphogenetic changes and cytodifferentiation of tumour myoepithelial cell lineage in culture.

Effect of N-CAM on in vitro invasion of human adenoid cystic carcinoma cells

Adenoid cystic carcinoma of salivary glands is characterised by aggressive behaviour, high rate of local recurrences, neurotropism and late metastasis. In a previous work we demonstrated that adenoid cystic carcinoma cultured cells (CAC2 cells) expressed N-CAM. It was suggested that this expression, modulated by extracellular matrix, would be correlated to cell movement. The aim of our study was to verify whether CAC2 cells presented invasion capacity. Moreover, we tested whether the neural adhesion molecule (N-CAM) would participate in this process. CAC2 cells were either previously treated, or not (control), with a monoclonal antibody against N-CAM. Invasion assays were carried out using a modified Boyden chamber (Transwell chamber). CAC2 cells (10(5)) were dispensed into Transwell upper chamber on the top of Matrigel coated filter. The cells that invaded the filters in the first 8 h were counted under light microscopy, yielding data for the invasion rates (%). Control CAC2 cells presented an invasion rate of 5.28+/-0.04%. The invasion rate raised to 6.53+/-0.2% when N-CAM was blocked with monoclonal antibody. N-CAM impaired the adenoid cystic carcinoma cell invasion in vitro. Therefore, we suggest an anti-invasive role for N-CAM in adenoid cystic carcinoma.

The role of basement membrane proteins on the expression of neural cell adhesion molecule (N-CAM) in an adenoid cystic carcinoma cell line

We investigated the presence of neural cell adhesion molecule (N-CAM) in the adenoid cystic carcinoma cell line CAC2 using immunofluorescence microscopy. Additionally, we analysed the role of laminin and type IV collagen in N-CAM expression. We demonstrated that cultured adenoid cystic carcinoma cells express N-CAM. Control cells presented a scattered N-CAM expression on cell membrane, and type IV collagen had no effect in N-CAM distribution. CAC2 cells grown on laminin-coated coverslips expressed N-CAM concentrated on cell lamellipodia suggesting relationship with migratory activity. Our results showed that cultured adenoid cystic carcinoma cells express N-CAM and this expression is modulated by extracellular matrix.

Expression of smooth-muscle actin in cultured cells from human plasmacytoid myoepithelioma

OBJECTIVEnThe definition of plasmacytoid myoepithelioma, a neoplasm exhibiting myoepithelial differentiation, has been recently questioned. To better understand the histogenesis of this neoplasm, we searched for myoepithelial markers in histologic sections of plasmacytoid myoepithelioma and in a cell line (M1) derived from this same neoplasm.nnnSTUDY DESIGNnExpression of vimentin, pan-keratin (AE-3) and smooth-muscle actin was studied by immunohistochemistry in paraffin-embedded tissue and by immunofluorescence in M1 cells.nnnRESULTSnPlasmacytoid myoepithelioma tumor sections showed vimentin and AE-3 reactivity, but evidence of smooth-muscle actin was not seen. The cell line derived from this tumor also produced vimentin and cytokeratin. In addition, all cultured cells expressed smooth-muscle actin.nnnCONCLUSIONnWe demonstrated that cells derived from a case of plasmacytoid myoepithelioma appear to show full myoepithelial differentiation in vitro. Thus, they are myoepithelial-like cells in nature. The lack of myogenous differentiation in vivo could be due to an inhibitory process mediated by the extracellular matrix.

The effect of a reconstituted basement membrane (Matrigel) on a human salivary gland myoepithelioma cell line

Abstract We have already demonstrated that a reconstituted basement membrane (Matrigel) is a key modulator of morphogenetic changes and cytodifferentiation of pleomorphic adenoma cells in culture. Myoepithelioma is considered to be a neoplasm closely related to pleomorphic adenoma and should experience similar induction processes. Thus, the aim of this study was to investigate whether Matrigel would influence myoepithelioma cells. We used a cell line derived from a human salivary gland plasmacytoid myoepithelioma (M1 cells) grown in a three-dimensional preparation of Matrigel. Phenotype differences were assessed using conventional light microscopy technique (haematoxylin and eosin) and phase and differential interference contrast (Nomarski). Immunofluorescence was carried out to detect smooth-muscle actin, laminin and type-IV collagen. M1 cells exhibited all proteins studied, showing a myoepithelial differentiation. M1 cells grown inside Matrigel presented morphological changes and changes in smooth-muscle actin status. By growing M1 cells inside Matrigel, it was possible to reproduce the tumour architecture with no duct-like structures. Based on our findings, we suggest that myoepithelioma would be derived from a cell with a commitment to myoepithelial differentiation. We also suggest that the mechanical properties of the matrix environment will likely regulate smooth-muscle actin expression in myoepithelioma.

Avaliação da citotoxicidade de dois sistemas adesivos

The purpose of the present study was to evaluate the cytotoxicity of two different dentin-bonding agents on cell cultures. NIH-3T3 fibroblasts were plated in Petri dishes. After 48 hours, when the cells were in confluence, primers and adhesives of two dentin bonding systems (Scotchbond Multipurpose Plus and Clearfil Liner Bond 2) were applied on glass slides, which were placed in the dishes. Composite resin and calcium hydroxide were also used. Polymerization, when required, was performed with a XL 1500 light unit. No material was used in the control group. All materials remained in contact with the cells for 24 hours, except for phosphoric acid, which was maintained for 20 seconds. After that, cells were counted in a hemocytometer and cell viability was obtained by tripan blue dye exclusion. The data were submitted to statistical analysis (ANOVA and Tukeys test). It was possible to conclude that all materials tested presented lower cell viability than the control group, except calcium hydroxide. Composite resin and phosphoric acid application caused similar viability rates as calcium hydroxide. Primers plus adhesive application of both adhesive systems produced similar cytotoxicicity, both causing smaller cell viability than that of calcium hydroxide group. No differences were found in relation to the cytotoxic effects of the components in both adhesive systems.

Action of low-power laser irradiation on the proliferation of human gingival fibroblasts in vitro

The low level power laser has been used in dental treatments aiming to improve tissue healing. An in vitro study was performed to analyze the laser influence on gingival fibroblast. A human gingival fibroblast culture (LMF) was produced in DME medium with 10% bovine fetal serum (BFS) cells (LMF) were allocated in Petri plates and cultured in different SFB concentrations (0%, 5% e 10%). After 48 hours the plates were divided in 9 groups: 3 control: 3 irradiated by 635 nm laser; and 3 irradiated by 780 nm laser. The cultured cells received 4 applications, in 12 hours intervals, with energy dosage of 2 joules for each plate, by means of a punctual technique. The growth curves showed that the growth levels were lower in low BFS concentrations. The irradiation with laser accelerated the growth rate in all groups. Additionally, the number of cells developed in low BFS concentration (5%) and irradiated was similar to the number of control cells developed in ideal conditions (10% BFS). There was no statistically significant differences between the effects of the two types of laser studied.