Ruy G. Jaeger

Evidence for superoxide radical-dependent coronary vasospasm after angioplasty in intact dogs.

BackgroundActive oxygen species can influence vascular tone and platelet activation through a variety of mechanisms. This study assessed the role of the superoxide anion, the hydroxyl radical, and hydrogen peroxide in vasoconstriction and mural thrombosis after coronary artery angioplasty in intact dogs. Methods and ResultsInjury was induced by inflation of a balloon catheter 50±6% above baseline arterial diameter; dogs were followed for 2 hours before death. Epicardial coronary diameters at arteriography and extent of thrombus deposition at serial histological sections were analyzed in controls (n =20) and in dogs pretreated with superoxide dismutase (SOD, a superoxide radical scavenger, n = 10); other dogs were pretreated with the hydrogen peroxide scavenger catalase (n =8), the iron chelator deferoxamine (n =6), or the hydroxyl radical scavenger 1,3-dimethyl-2-thiourea (n =9). Angioplasty-induced injury was similar among groups. After angioplasty, control dogs exhibited localized and persistent vessel constriction, which was maximal at the initial 5 minutes (28.9 + 6.3% diameter decrease versus baseline). Corresponding arterial diameters of SOD-treated dogs were 24–69% larger (95% confidence interval, p < 0.001) than controls at 5 minutes and, on average, 32% larger than controls thereafter (p < 0.01). Vasoconstriction was not prevented by the other treatments. The SOD dose used accounted for inhibition of zymosan-stimulated blood cytochrome c reduction versus baseline (7 + 3 versus 30±6 nmol/min/106 cells, respectively, p = 0.003); such inhibition occurred in no other group. Prevalence of mural thrombosis was similar among all groups, but large thrombi (>15% of lumen area) were absent in SOD-treated dogs, contrary to control group (p = 0.028); other groups were similar to control. In the absence of injury, SOD alone induced no change in coronary diameter, coronary blood flow, or platelet aggregation. ConclusionsThese data provide evidence implicating the superoxide radical in the genesis of vasoconstriction after coronary angioplasty in vivo. Such effects seem to be independent of its conversion to hydroxyl radicals and availability of hydrogen peroxide or catalytic iron complexes.

Local invasiveness of ameloblastoma. Role played by matrix metalloproteinases and proliferative activity

Aims:  Ameloblastoma is an odontogenic neoplasm characterized by local invasiveness and recurrence. In this study we analysed the role played by matrix metalloproteinases (MMPs) in the local invasiveness of ameloblastoma. We also attempted to establish a relationship between the presence of MMPs and the proliferative activity of ameloblastoma cells.

Collagen Hydrolysate Intake Increases Skin Collagen Expression and Suppresses Matrix Metalloproteinase 2 Activity

The effect of daily ingestion of collagen hydrolysate (CH) on skin extracellular matrix proteins was investigated. Four-week-old male Wistar rats were fed a modified AIN-93 diet containing 12% casein as the reference group or CH as the treatment group. A control group was established in which animals were fed a non-protein-modified AIN-93 diet. The diets were administered continuously for 4 weeks when six fresh skin samples from each group were assembled and subjected to extraction of protein. Type I and IV collagens were studied by immunoblot, and activities of matrix metalloproteinase (MMP) 2 and 9 were assessed by zymography. The relative amount of type I and IV collagens was significantly (P < .05) increased after CH intake compared with the reference diet group (casein). Moreover, CH uptake significantly decreased both proenzyme and active forms of MMP2 compared with casein and control groups (P < .05). In contrast, CH ingestion did not influence on MMP9 activity. These results suggest that CH may reduce aging-related changes of the extracellular matrix by stimulating anabolic processes in skin tissue.

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 geodiamolide H, derived from brazilian sponge Geodia corticostylifera, regulates actin cytoskeleton, migration and invasion of breast cancer cells cultured in three-dimensional environment

We are investigating effects of the depsipeptide geodiamolide H, isolated from the Brazilian sponge Geodia corticostylifera, on cancer cell lines grown in 3D environment. As shown previously geodiamolide H disrupts actin cytoskeleton in both sea urchin eggs and breast cancer cell monolayers. We used a normal mammary epithelial cell line MCF 10A that in 3D assay results formation of polarized spheroids. We also used cell lines derived from breast tumors with different degrees of differentiation: MCF7 positive for estrogen receptor and the Hs578T, negative for hormone receptors. Cells were placed on top of Matrigel. Spheroids obtained from these cultures were treated with geodiamolide H. Control and treated samples were analyzed by light and confocal microscopy. Geodiamolide H dramatically affected the poorly differentiated and aggressive Hs578T cell line. The peptide reverted Hs578T malignant phenotype to polarized spheroid‐like structures. MCF7 cells treated by geodiamolide H exhibited polarization compared to controls. Geodiamolide H induced striking phenotypic modifications in Hs578T cell line and disruption of actin cytoskeleton. We investigated effects of geodiamolide H on migration and invasion of Hs578T cells. Time‐lapse microscopy showed that the peptide inhibited migration of these cells in a dose‐dependent manner. Furthermore invasion assays revealed that geodiamolide H induced a 30% decrease on invasive behavior of Hs578T cells. Our results suggest that geodiamolide H inhibits migration and invasion of Hs578T cells probably through modifications in actin cytoskeleton. The fact that normal cell lines were not affected by treatment with geodiamolide H stimulates new studies towards therapeutic use for this peptide. J. Cell. Physiol. 216: 583–594, 2008,

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.

Decreased expression of ADAMTS-1 in human breast tumors stimulates migration and invasion

BackgroundADAMTS-1 (a disintegrin and metalloprotease with thrombospondin motifs) is a member of the ADAMTS family of metalloproteases. Here, we investigated mRNA and protein levels of ADAMTS-1 in normal and neoplastic tissues using qPCR, immunohistochemistry and immunoblot analyses, and we addressed the role of ADAMTS-1 in regulating migration, invasion and invadopodia formation in breast tumor cell lines.ResultsIn a series of primary breast tumors, we observed variable levels of ADAMTS-1 mRNA expression but lower levels of ADAMTS-1 protein expression in human breast cancers as compared to normal tissue, with a striking decrease observed in high-malignancy cases (triple-negative for estrogen, progesterone and Her-2). This result prompted us to analyze the effect of ADAMTS-1 knockdown in breast cancer cells in vitro. MDA-MB-231 cells with depleted ADAMTS-1 expression demonstrated increased migration, invasion and invadopodia formation. The regulatory mechanisms underlying the effects of ADAMTS-1 may be related to VEGF, a growth factor involved in migration and invasion. MDA-MB-231 cells with depleted ADAMTS-1 showed increased VEGF concentrations in conditioned medium capable of inducing human endothelial cells (HUVEC) tubulogenesis. Furthermore, expression of the VEGF receptor (VEGFR2) was increased in MDA-MB-231 cells as compared to MCF7 cells. To further determine the relationship between ADAMTS-1 and VEGF regulating breast cancer cells, MDA-MB-231 cells with reduced expression of ADAMTS-1 were pretreated with a function-blocking antibody against VEGF and then tested in migration and invasion assays; both were partially rescued to control levels.ConclusionsADAMTS-1 expression was decreased in human breast tumors, and ADAMTS-1 knockdown stimulated migration, invasion and invadopodia formation in breast cancer cells in vitro. Therefore, this series of experiments suggests that VEGF is involved in the effects mediated by ADAMTS-1 in breast cancer cells.

Matrix metalloproteinases, TIMPs and growth factors regulating ameloblastoma behaviour

Siqueira A S, Carvalho M R D, Monteiro A C D, Freitas V M, Jaeger R G & Pinheiro J J V.
(2010) Histopathology 57, 128–137
Matrix metalloproteinases, TIMPs and growth factors regulating ameloblastoma behaviour

Er:YAG Laser Effects on Enamel Occlusal Fissures: An in Vitro Study

This study evaluated by scanning electron microscopy (SEM) the morphological changes in occlusal fissure enamel, of permanent models, irradiated by Er:YAG laser using contact and noncontact fiberoptics in vitro. Previous studies have demonstrated the efficacy of Er:YAG laser for dental hard tissue removal and cavity preparation. The treatment of occlusal fissures in noncarious permanent human molars (n = 9) was carried out with Er:YAG laser (KEY Laser II) using handpiece no. 2051, noncontact, focused (12 mm), water spray-cooled, pulse energy 200 mJ, and frequency 2 Hz (group 1), and handpiece no. 2055 with a quartz fiberoptic 50/10, in contact, air cooled, pulse energy setting of 350 mJ and frequency 2 Hz (group 2) and 400 mJ/2 Hz (group 3). The specimens were sectioned, dehydrated in a graded series of aqueous ethanol, dried, and sputtering with gold. Morphological change analysis on occlusal fissures was performed by SEM. Group 1 showed removal of fissure debris and predominantly enamel etching-like patterns, and groups 2 and 3 showed irregular edges, melting, and recrystallization of fissure enamel, with a lava-like structure and bubble-like voids. The results of this in vitro study suggest that the irradiation of fissures by Er:YAG laser using a fiberoptics (contact and air cooled) produced melting and recrystallization of fissures enamel. Further studies are required with different energy parameters and water cooling to evaluate the thermal effects on teeth.

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

Abstract In 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.