899 resultados para ELASTIC FIBERS
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The intimal layer of the thoracic and abdominal aortic segments of Cebus apella monkey presented an evident inner elastic lamina. The medial layer of the thoracic aorta segment showed a basic lamellar elastic pattern having a medium average of 23.12 lamellae per analyzed cut sections, which appeared disposed circular and oblique relatively to the aortic lumen. The aortic adventitial layer, at this level, was formed mainly by collagen fibers, irregularly disposed between elastic fibers and smooth muscle cells. The aortic abdominal portion, in this monkey, at the suprarenal level presented a medium number of 19.12 elastic lamellae which showed a relatively disorganized and broken up pattern. At the infrarenal level the aortic medium layer showed a medium average of 11.75 elastic lamellae and next to the emission of the internal iliac arteries it was found only a middle average of 8.37 elastic lamellae intermingled with smooth muscle cells and collagen fibers whose concentration seemed to be increased next to the adventitial layer. The external elastic lamina was only present in the more distal aortic segment near to the emission of the internal iliac arteries.
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Background: Smoking is the most relevant environmental factor that affects the development of aortic aneurysm. Smokers have elevated levels of elastase activity in the arterial wall, which leads to weakening of the aorta. The aim of this study was to verify whether cigarette smoke exposure itself is capable of altering the aortic wall. Methods: Forty-eight Wistar rats were divided into 2-, 4-, and 6-month experimental periods and into 2 groups: smokers (submitted to smoke exposure at a rate of 40 cigarettes/day) and nonsmokers. At the end of the experimental periods, the aortas were removed and cross-sectioned to obtain histologic specimens for light microscopic and morphometric analyses. The remaining longitudinal segments were stretched to rupture and mechanical parameters were determined. Results: A degenerative process (i.e., a reduction in elastic fibers, the loss of lamellar arrangement, and a reduction of smooth muscle cells) was observed, and this effect was proportional in intensity to the period of tobacco exposure. We observed a progressive reduction in the yield point of the thoracic aorta over time (P < 0.05). There was a decrease in stiffness (P < 0.05) and in failure load (P < 0.05) at 6 months in the abdominal aorta of rats in the smoking group. Conclusions: Chronic exposure to tobacco smoke can affect the mechanical properties of the aorta and can also provoke substantial structural changes of the arterial wall. © 2013 Elsevier Inc. All rights reserved.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Medicina Veterinária - FMVZ
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Cancer is a multistep process that begins with the transformation of normal epithelial cells and continues with tumor growth, stromal invasion and metastasis. The remodeling of the peritumoral environment is decisive for the onset of tumor invasiveness. This event is dependent on epithelial–stromal interactions, degradation of extracellular matrix components and reorganization of fibrillar components. Our research group has studied in a new proposed rodent model the participation of cellular and molecular components in the prostate microenvironment that contributes to cancer progression. Our group adopted the gerbil Meriones unguiculatus as an alternative experimental model for prostate cancer study. This model has presented significant responses to hormonal treatments and to development of spontaneous and induced neoplasias. The data obtained indicate reorganization of type I collagen fibers and reticular fibers, synthesis of new components such as tenascin and proteoglycans, degradation of basement membrane components and elastic fibers and increased expression of metalloproteinases. Fibroblasts that border the region, apparently participate in the stromal reaction. The roles of each of these events, as well as some signaling molecules, participants of neoplastic progression and factors that promote genetic reprogramming during epithelial–stromal transition are also discussed.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Ayahuasca is a hallucinogenic brew traditionally used by Northwestern Amazonian indigenous groups for therapeutic purposes. It is prepared by the decoction of Banisteriopsis caapi with the leaves of Psychotria viridis. Banisteriopsis caapi contains β-carbolines that are inhibitors of monoamine oxidase and P. viris is rich in dimethyltryptamine, a 5-HT(1A/2A/2C) agonist. Acute ayahuasca administration produces moderate cardiovascular effects in healthy volunteers, but information regarding long-term use is lacking. This study investigated the effects of ayahuasca (2-4 mL/kg) in the rat aorta after acute and chronic (14 days) administration. Ayahuasca caused flattening and stretching of vascular smooth muscle cells and changes in the arrangement and distribution of collagen and elastic fibers. Chronic treatment with the higher dose significantly increased media thickness and the ratio of media thickness to lumen diameter. More research is needed on the cardiovascular function of long-term ayahuasca consumers.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Bases Gerais da Cirurgia - FMB
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Pós-graduação em Bases Gerais da Cirurgia - FMB
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The aim of this study was to analyze the presence and distribution of total collagen, type I and type III collagen, elastic fibers, fibronectin, and versican in the endomysium of cricopharyngeus muscles from adults of various ages. The study was a cross-sectional analysis of human cricopharyngeus muscles. Twenty-seven muscles obtained from autopsies of men and women ranging in age from 28 to 92 years were analyzed with the Picrosirius method, oxidized Weigert resorcin-fuchsin, immunohistochemistry, and image analysis. Collagen had the highest density among the analyzed components. Elastic fibers surrounded each muscle cell; they were aligned longitudinally by their long axis and associated with traversing fibers, thereby forming a fiber network with embedded muscle cells. The fibronectin and versican contents varied widely among the specimens. We found no statistically significant differences between the proportion of extracellular matrix (ECM) components and factors such as gender and race. We conclude that the higher proportion of type I and type III collagen is compatible with the cricopharyngeus muscle's sphincteric behavior, and the arrangement of the elastic fibers may also contribute to the muscle's elasticity. We found no statistically significant correlation between the ECM components and age.
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Sarmento C. A. P., Ferreira A. O., Rodrigues E. A. F., Lesnau G. G., Rici R. E. G., Abreu D. K., Biasi C. & Miglino M. A. 2012. [Kidney of Minke Whale (Baleanoptera acutorostrata): Architecture and structure.] Rins de Baleia Minke (Baleanoptera acutorostrata): arquitetura e estrutura. Pesquisa Veterinaria Brasileira 32(8): 807-811. Departamento de Cirurgia, Setor de Anatomia dos Animais Domesticos e Silvestres, Universidade de Sao Paulo, Av. Prof. Dr. Orlando Marques de Paiva 87, Sao Paulo, SP 05508-270, Brazil. E-mail: sarmento@usp.br Among marine mammals, whale is one of the most attention-arousing animals, especially concerning its urinary tract. This system follows the pattern of mammals with regard to its constitution, however, it differs in renal morphology and number of lobes, which, in turn, form complete reniculi, agglutinated in hundreds. This structure is supported by fibrous connective tissue, but highly capable of maintaining electrolyte balance. Six pairs of kidneys of Minke whale (Balaenoptera acutorostrata), collected in 1982, in Cabedelo, Paraiba, Brazil, in the last fishing allowed, were dissected. These kidneys were preserved in 10% formaldehyde and they presented a very large histologic layer of collagen surrounding the medullary wall. The urinary collecting duct form papillary glasses, that reach a single collecting center which discharges in the ureter. It was found that the kidney of Minke whale has a lobe characteristic, with, on average, 700 reniculi; each reniculus has anatomical and functional characteristics of a unipyramidal kidney, with an inner layer (medulla), and an outer layer (cortex), and independent irrigation, with formation of individually arcuate arteries, as observed in unipyramidal terrestrial mammals. However, the set gathering all these reniculi constitutes, in the end, a multilobular and polipyramidal kidney, contrary to the morphology of most terrestrial mammals. It was not possible to distinguish the renicular cortex structures of the Minke whale in the level of light microscopy. Through scanning electron microscopy, it was possible to visualize a cortical layer located between two fibrous capsules. This joint, in turn, consists of connective tissue, which, along with a layer of collagen and elastic fibers, separates the cortex from the medulla; the kidney glomeruli were visualized, completely taken by the glomerular vessels and arranged into several layers. One notices that the glomerular cavity is almost a virtual space into which the glomerular filtrate is drained, and it does not present a globular shape. Vascularization is increased in the medullary region. The difference between the kidneys of terrestrial and marine mammals consists in the arrangement of morphological components, favoring the organ's physiology.