934 resultados para Vascular smooth muscle.
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Vinte perdizes Rhynchotus rufescens adultas foram utilizadas para estudo morfológico do proventrículo e ventrículo gástricos da perdiz Rhynchotus rufescens. Os materiais foram coletados e os comprimentos do proventrículo e do ventrículo gástricos foram avaliados. Para o estudo histológico, fragmentos dos estômagos foram corados pelas técnicas de ácido periódico de Schiff (PAS) e tricromo de Masson. O proventrículo gástrico é alongado, com formato fusiforme direcionado no sentido craniocaudalmente e para a esquerda, e apresenta um comprimento médio 3,20cm nas fêmeas e 3,65cm nos machos. Histologicamente, o proventrículo gástrico é composto por vários lobos e glândulas. A mucosa é formada por epitélio cúbico, sendo bastante pregueada. O ventrículo gástrico tem o formato de uma lente biconvexa, com comprimento médio de 4,30cm nas fêmeas e 4,35cm nos machos. A mucosa é formada por pregas revestidas por células cilíndricas e pelo muco formador da cutícula. Há criptas na base das pregas. em seguida, há uma lâmina própria e uma espessa camada muscular lisa, que se encontra direcionada de acordo com o formato do ventrículo gástrico. A serosa é constituída por uma densa porção de tecido conjuntivo, entremeado por algumas células musculares lisas.
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The effects of adrenergic stimulation on mean circulatory filling pressure (MCFP), central venous pressure (P-CV) and stroke volume (Vs), as well as the effects of altered MCFP through changes of blood volume were investigated in rattlesnakes (Crotalus durissus). MCFP is an estimate of the upstream pressure driving blood towards the heart and is determined by blood volume and the activity of the smooth muscle cells in the veins (venous tone). MCFP can be determined as the plateau in P-CV during a total occlusion of blood flow from the heart.Vs decreased significantly when MCFP was lowered by reducing blood volume in anaesthetised snakes, whereas increased MCFP through infusion of blood (up to 3 ml kg(-1)) only led to a small rise in Vs. Thus, it seems that end-diastolic volume is not affected by an elevated MCFP in rattlesnakes. To investigate adrenergic regulation on venous tone, adrenaline as well as phenylephrine and isoproterenol (alpha- and beta-adrenergic agonists, respectively) were infused as bolus injections (2 and 10 mu g kg(-1)). Adrenaline and phenylephrine caused large increases in MCFP and P-CV, whereas isoproterenol decreased both parameters. This was also the case in fully recovered snakes. Therefore, adrenaline affects venous tone through both alpha- and beta-adrenergic receptors, but the alpha-adrenergic receptor dominates at the dosages used in the present study. Injection of the nitric oxide donor SNP caused a significant decrease in P-CV and MCFP. Thus, nitric oxide seems to affect venous tone.
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The odontogenic keratocysts are distinguished from other odontogenic cystic lesions by their potentially aggressive clinical behavior and association, in some cases, with Gorlin syndrome. Studies have suggested that syndrome keratocysts, in comparison with sporadic lesions, have higher growth and infiltration capacity and higher recurrence tendency. The aim of this study was to analyze, by means of immunohistochemistry, the expressions of receptor activator of nuclear factor κB ligand (RANKL) and osteoprotegerin (OPG), the angiogenic index (CD34) and the presence of myofibroblasts (α-SMA) in primary and recurrent sporadic keratocysts and in keratocysts associated with Gorlin syndrome. The sample was composed by 30 sporadic keratocysts (22 primary and 8 recurrent) and 22 syndrome keratocysts. In the epithelium and in the fibrous capsule of the lesions, the immunoexpression of RANKL and OPG was evaluated by determination of the percentage of positive cells, according to the following scores: 0 (less than 10% of positive cells), 1 (11% - 50% of positive cells), 2 (51% - 75% of positive cells) and 3 (more than 76% of positive cells). In addition, cases were classified according to the RANKL score/ OPG score ratio, as follows: RANKL > OPG, RANKL < OPG, and RANKL = OPG. The angiogenic index was analyzed by counting the microvessels immunoreactive to anti-CD34 antibody in 5 fields (200). The analysis of myofibroblasts was performed by counting the cells immunoreactive to anti-α-SMA antibody in 10 fields (400). The analysis of the expressions of RANKL and OPG in the epithelial lining and in the fibrous capsule did not reveal significant differences between groups (p > 0.05). Regarding the RANKL/ OPG ratio in the epithelial lining, most sporadic primary (54.5%) and syndrome lesions (59.1%) showed RANKL < OPG ratio and RANKL = OPG ratio, respectively (p > 0.05). With respect to the RANKL/ OPG ratio in the fibrous capsule, the majority of sporadic primary (81.8%) and sporadic recurrent lesions (75.0%) and most syndrome lesions (45.5%) showed RANKL = OPG ratio (p > 0.05). The mean number of microvessels was 69.2 in sporadic primary lesions, 67.6 in recurrent lesions, and 71.6 in syndrome lesions, with no significant differences between groups (p > 0.05). The mean number of myofibroblasts was 34.4 in sporadic primary lesions, 29.3 in recurrent lesions, and 33.7 in syndrome lesions, with no significant differences between groups (p > 0.05). In conclusion, the results of the present study suggest that the differences in the biological behavior between sporadic keratocysts and keratocysts associated with Gorlin syndrome may not be related to the expressions of RANKL and OPG, the RANKL/ OPG ratio, the angiogenic index or the number of myofibroblasts in these lesions
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The rat tapeworm, Hymenolepis diminuta, induces mastocytosis, hypertrophy of enteric smooth muscle, alteration of enteric myoelectric activity, and slowed enteric transit of the rat host's intestine. This report examines the resolution of both tapeworm-induced mastocytosis and tissue changes during the period following removal of the tapeworm with Praziquantel (PZQ). The dynamics of the mucosal mast cell (MMC) population following removal of the tapeworms was assessed by histochemical identification of MMC and morphometric techniques. As a possible mechanism of MMC population regulation, MMC apoptosis was examined over the same experimental period using the in situ nick end labeling of fragmented DNA (TUNEL). Shifts in MMC numbers were correlated with functional and morphological changes of the intestine following removal of the adult-stage tapeworm. Ileal tissues from rats infected 32 days with H. diminuta (the beginning of plateau phase of tapeworm-induced chronic mastocytosis) were harvested 1, 2, 3, and 4 weeks after the PZQ treatment. Control ilea were obtained either from rats which were never infected and never treated with PZQ or from rats infected with H, diminuta for 32 days but not treated with PZQ. In order to detect MMC and apoptosis, tissue sections of ileum were doubled stained sequentially with Astra blue for MMC granules followed by a modification of the TUNEL technique. No alteration in MMC numbers were observed in PZQ-treated animals until 3 weeks after the removal of the tapeworms. The decline of MMC occurred in the mucosa and submucosa. MMC numbers first approached uninfected control levels at 4 weeks posttreatment. Coincident with the decline in mucosal MMC numbers, the rate of MMC entering apoptosis also declined. Simultaneously, ileal smooth muscle layers, hypertrophied by infection, and mucosal structures began the process of involution and atrophy. Apoptosis of MMC in the submucosa and muscularis mucosa was not detected. In conclusion, H. diminuta elicited mastocytosis and increased thickness of both mucosa and muscularis externa do not begin a decline toward control Values until 3 weeks after the parasites are gone and normal intestinal motility is restored. These data are consistent with the lack of MMC mediation of altered motility, and the decline in the rate of MMC apoptosis at 3 weeks post-PZQ suggests that apoptosis may play an important role in the involution of tapeworm-induced mastocytosis. (C) 1999 Academic Press.
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The activation of hepatic stellate cells (HSC) is considered the most important event in hepatic fibrogenesis. The precise mechanism of this process is unknown in autoimmune hepatitis (AIH), and more evidence is needed on the evolution of fibrosis. The aim of this study was to assess these aspects in children with type 1 AIH. We analyzed 16 liver biopsy samples from eight patients, paired before treatment and after clinical remission, performed an immunohistochemical study with anti-actin smooth muscle antibody and graded fibrosisand inflammation on a scale of 0:4 (Batts and Ludwig scoring system). We observedthere was no significant reduction in fibrosis scores after 24± 18 months (2.5 ± 0.93 vs. 2.0± 0.53, P = 0.2012). There was an important decrease in inflammation: portal (2.6 ±0.74 vs. 1.3± 0.89, P = 0.0277), periportal/periseptal (3.0 ±0.76 vs. 1.4 ± 1.06, P = 0.0277), and lobular (2.8 ± 1.04 vs. 0.9± 0.99, P =0.0179). Anti-actin smooth muscle antibodies were expressed in the HSC of the initial biopsies (3491.93 ±2051.48 lm2), showing a significant reduction after remission (377.91 ±439.47 lm2) (P = 0.0117). HSC activation was demonstrated in the AIH of children. The reduction of this activation after clinical remission, which may precede a decrease in fibrosis, opens important perspectives in the follow-up of AIH.
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Myofibroblasts are cells that exhibit a hybrid phenotype, sharing the morphological characteristics of fibroblasts and smooth muscle cells, which is acquired during a process called differentiation. These cells then start to express -SMA, a marker that can be used for their identification. Studies suggest that myofibroblasts are related to the aggressiveness of different tumors and that TGF-1 and IFN- play a role in myofibroblast differentiation, stimulating or inhibiting this differentiation, respectively. The objective of this study was to investigate the role of myofibroblasts in epithelial odontogenic tumors, correlating the presence of these cells with the aggressiveness of the tumor. Immunohistochemistry was used to evaluate the expression of TGF-1 and IFN- in myofibroblast differentiation, as well as the expression of MMP-13, which is activated by myofibroblasts, and of EMMPRIN (extracellular matrix metalloproteinase inducer) as a precursor of this MMP. The sample consisted of 20 solid ameloblastomas, 10 unicystic ameloblastomas, 20 odontogenic keratocysts, and 20 adenomatoid odontogenic tumors. For evaluation of myofibroblasts, anti- -SMA-immunoreactive cells were quantified in connective tissue close to the epithelium. Immunoexpression of TGF-1, IFN-, MMP-13 and EMMPRIN was evaluated in the epithelial and connective tissue components, attributing scores of 0 to 4. The results showed a higher concentration of myofibroblasts in solid ameloblastomas (mean of 30.55), followed by odontogenic keratocysts (22.50), unicystic ameloblastomas (20.80), and adenomatoid odontogenic tumors (19.15) (p=0.001). No significant correlation between TGF-1 and IFN- was observed during the process of myofibroblast differentiation. There was also no correlation between the quantity of myofibroblasts and MMP-13 expression. Significant correlations were found between MMP-13 and TGF-1 (r=0.087; p=0.011), between MMP- 13 and IFN- (r=0.348; p=0.003), as well as between EMMPRIN and MMP-13 (r=0.474; p<0.001) and between EMMPRIN and IFN- (r=0.393; p=0.001). The higher quantity of myofibroblasts observed in solid ameloblastomas, odontogenic keratocysts and unicystic ameloblastomas suggests that these cells are one of the factors responsible for the more aggressive biological behavior of these tumors, although the myofibroblast population was not correlated with TGF-1, IFN-, MMP-13 or EMMPRIN. The correlation between MMP- 13 and TGF-1 suggests that the latter induces the expression of this metalloproteinase. The present results also support the well-established role of EMMPRIN as an inducer of MMP-13. Furthermore, the relationship between EMMPRIN and IFN- and between MMP-13 and IFN- suggests synergism in the antifibrotic effect of these markers
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Uterine leiomyomas are extremely common, benign, smooth muscle tumors that represent a significant public health problem. Although there have been few molecular studies of uterine leiomyomas, most of them have reported a very low frequency of loss of heterozygosity (LOH) in different regions of the genome. The detection of LOH has been used to identify genomic regions that harbor tumor suppressor genes and to characterize different tumor types. We have used a set of 15 microsatellite polymorphism markers to examine the frequency of allele loss in a panel of 64 human uterine leiomyomas matched to normal DNAs. The markers were chosen from regions involved in losses identified by comparative genomic hybridization in a subset of uterine leiomyomas described in a previous report. DNA from tumors and normal tissue was amplified by the polymerase chain reaction and subsequently analyzed using an ABI Prism 377 DNA automated sequencer. The frequency of LOH observed was low, except for the markers D15S87 (15q26.3), D7S493 (7p15.3), and D7S517 (7p22.2). No changes in microsatellite size were detected in our samples. These results provide useful clues for identifying putative tumor suppressor genes associated with a subset of uterine leiomyomas. (C) 2004 Wiley-Liss, Inc.
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The perivascular epithelioid cell has been proposed to be the unifying proliferating cell type in a number of lesions such as angiomyolipoma, lymphangiomyomatosis, clear cell sugar tumor and renal capsuloma. With the exception of rare examples of angiomyolipoma, they are non-metastasizing. We report four examples of a new member of this family of perivascular epithelioid cell neoplasms that occur in abdominopelvic location and show metastatic properties. The patients, all women, were aged 19 to 41 years (mean, 32), and presented with a tumor mass involving the serosa of the ileum, uterus or pelvic cavity. Morphologically, the tumors were composed of sheets of large polygonal cells with glycogen-rich clear or eosinophilic cytoplasm and moderately pleomorphic nuclei, traversed by a delicate vasculature, mimicking clear cell carcinoma. There were areas of coagulative necrosis and occasional mitotic figures. Intracytoplasmic brown pigment was present in two cases. Spindly cells, smooth muscle and fat were absent. Lymphovascular invasion was present in all, lymph node metastasis was documented in two and metastasis to the ovary was present in one case. Two patients developed widespread metastatic disease after 10 and 28 months from diagnosis. One patient showed the clinical signs of tuberous sclerosis. In spite of the epithelial-like appearance, the tumor cells were negative for epithelial markers but were strongly positive with the melanogenesis-related marker HMB45. Another melanogenesis marker (MART-1) was positive in two cases. Other markers including S-100 protein, vimentin, muscle-specific actin, desmin and chromogranin A were negative. Thus, these tumors are not readily classifiable in the existing schema of known entities, and show over-lapping morpho-phenotypic features of clear cell sugar tumor of the lung and epithelioid angiomyolipoma. We consider them as sarcomas composed of a pure population of uncommitted perivascular epithelioid cell, that lack modulation toward smooth muscle or adipose cells.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Background: Spontaneous gastrointestinal neoplasms in non-human primates are commonly seen in aged individuals. Due to genetic similarities between human and non-human primates, scientists have shown increasing interest in terms of comparative oncology studies.Case presentation: The present study is related to a case of an intestinal leiomyoma in a black crested macaque (Macaca nigra), kept on captivity by Mateca a Zoo, Pereira City, Colombia. The animal had abdominal distension, anorexia, vomiting, diarrhea and behavioral changes. Clinical examination showed an increased volume in the upper right abdominal quadrant caused by a neoplastic mass. The patient died during the surgical procedure. Necropsy revealed several small nodules in the peritoneum with adhesion to different portions of the small and large intestines, liver, stomach and diaphragm. Tissue samples were collected, routinely processed and stained by H&E. Microscopic examination revealed a mesenchymal tumor limited to tunica muscularis, resembling normal smooth muscle cells. Neoplastic cells were positive for alpha-smooth muscle actin and vimentin, and negative for cytokeratin AE1/AE3 by immunohistochemistry. Those morphological and immunohistochemical findings allowed to diagnose the intestinal leiomyoma referred above.Conclusion: Neoplastic diseases in primates have multifaceted causes. Their manifestations are understudied, leading to a greater difficulty in detection and measurement of the real impact provides by this disease.
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Background: Uterine leiomyomas are common, benign, smooth muscle tumors representing a significant public health problem. The aim of this study was to investigate CYP17A1, CYP19, and androgen (AR) polymorphisms, their relative risks for uterine leiomyomas and possible associations with clinical parameters.Methods: Uterine leiomyoma tissues and blood samples were obtained from 87 patients, as were peripheral blood samples from 68 control women. Clinical data were recorded in both groups. The CYP17A1 (rs743572) polymorphism was analyzed by PCR-RFLP, and the CYP19 [TTTA](n) repeat and AR [CAG](n) repeat were analyzed using PCR-based GeneScan analysis. AR loss of heterozygosity (LOH) and microsatellite instability were also evaluated, while samples exhibiting LOH were analyzed for X inactivation.Results: Clinical parameters related to disease development did not differ between cases and controls. CYP17A1 *A2/*A2 genotype was prevalent in non-white women. CYP17A1, CYP19, and AR genotypes and alleles did not differ between groups. However, alleles presenting [TTTA](7) repeats in intron 4 of CYP19 were more frequent in the control group (p=0.0550). Shorter and longer [CAG]n repeat alleles of AR were exclusive to the leiomyoma group. The LOH assay showed allele losses at AR locus in four informative tumors and X chromosome inactivation analysis revealed that these tumors retained the active allele.Conclusions: The overall lack of association between uterine leiomyomas with polymorphisms involved in steroidogenesis or steroid metabolism is consistent with the hypothesis that these polymorphisms do not substantially contribute to the development of these tumors.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. on the other hand, weak staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues.Samples of tongue, submandibular and sublingual glands, cartilage, portions of respiratory tract and nervous ganglion were fixed in 4% formaldehyde and embedded in glycol methacrylate. The sections of tongue and nervous ganglion were stained by H&E. Picrosirius, Toluidine Blue and Sudan Black B methods were applied, respectively, for identification of collagen fibers in submandibular gland, sulfated glycosaminoglycans in cartilage (metachromasia) and myelin lipids in nervous ganglion. Periodic Acid-Schiff (PAS) method was used for detection of glycoconjugates in submandibular gland and cartilage while AB/PAS combined methods were applied for detection of mucins in the respiratory tract. In addition, a combination of Alcian Blue (AB) and Picrosirius methods was also assayed in the sublingual gland sections.The GMA-embedded tissue sections showed an optimal morphological integrity and were favorable to the staining methods employed in the present study. In the sections of tongue and nervous ganglion, a good contrast of basophilic and acidophilic structures was obtained by H&E. An intense eosinophilia was observed either in the striated muscle fibers or in the myelin sheaths in which the lipids were preserved and revealed by Sudan Black B. In the cartilage matrix, a strong metachromasia was revealed by Toluidine Blue in the negatively-charged glycosaminoglycans. In the chondrocytes, glycogen granules were intensely positive to PAS method. Extracellular glycoproteins were also PAS positive in the basal membrane and in the region occupied by the lamina externa and reticular fibers surrounding each smooth muscle cells of the blood vessels. In the epithelial cells of the respiratory tract, acid and neutral mucins were histochemically detected by AB and PAS methods, respectively. Moreover, granules containing acid and neutral mucins were revealed in purple by AB and PAS concomitantly. In the sublingual gland sections, a distinct affinity of acid mucins by AB (in turquoise-blue) and collagen fibers by Picrosirius (in red) was obtained when these methods were combined. Although some routine dyes used in paraffin sections have showed a weak stain in historesin sections, our results showed that different dyes could be applied in GMA sections if modified staining procedures were assayed. Therefore, appropriate staining contrast and, thus, detection of one or different substances in a same section can be acquired in association to the good morphological resolution provided by GMA. (C) 2003 Elsevier Ltd. All rights reserved.
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Androgen deprivation causes the rat ventral prostate to reduce to 10% of its original size by 21 days after castration. The regressive changes result from the loss of epithelial cells by apoptosis and marked reorganization of the stroma. We have investigated whether these changes are accompanied by variations in heparanase expression. The ventral prostate of castrated rats was collected and processed for the quantification of heparan sulfate (HS), for the measurement of heparanase expression and its localization by reverse transcription/polymerase chain reaction, Western blotting, and immunohistochemistry, and for transmission electron microscopy (TEM). Absolute HS content decreased significantly as early as day 7 after surgery. Heparanase mRNA peaked 7 days after castration. The heparanase proenzyme (65 kDa) and the active form (50 kDa) were identified and peaked on day 7 after castration; this coincided with maximum HS-degrading activity. Heparanase was located to the basolateral surface of epithelial cells and in the adjacent stroma. After castration, staining for heparanase was reduced in the epithelium and increased in the stroma. TEM revealed that the peak of heparanase expression at day 7 after castration was associated with extensive changes in the basement membrane of the epithelium, endothelium and smooth muscle cells involving cell shrinkage and/or deletion by apoptosis. These results suggest that heparanase expression increases after castration and correlates with a decreased amount of HS. This variation in heparanase expression is involved in tissue remodeling and in the control of the regressive pattern after 1 week of androgen deprivation.