942 resultados para Undifferentiated mesenchymal cells


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Nesta pesquisa foram obtidos dados histológicos e morfométricos comparativos sobre os testículos de gatos, pós-orquiectomia, divididos em dois grupos: Grupo 1, gatos com até 1 ano de idade e Grupo 2, animais acima de 1 ano. Verificou-se que: (1) aos 4 meses de idade os túbulos seminíferos apresentaram-se pouco desenvolvidos e com ausência de luz, epitélio seminífero baixo, células de Sertoli indiferenciadas e tecido intersticial escasso; (2) aos 5 meses os túbulos seminíferos começaram a se diferenciar com aumento do diâmetro e luz tubulares e as demais estruturas permaneceram semelhantes à observação anterior; (3) aos 6-7 meses ocorreu o início da espermatogênese e espermiogênese; as células de Leydig apareceram maiores, poliédricas com citoplasma vacuolizado e núcleo claro, e tecido intersticial esparso com poucos vasos sangüíneos; (4) os animais com 1 ano de idade apresentaram morfologia testicular igual à do animal adulto, com túbulos seminíferos de maior diâmetro, epitélio germinativo alto e luz tubular pequena, as células de Leydig aparecendo poliédricas, com dimensões variadas, citoplasma vacuolizado, núcleo claro e nucléolo evidente, e espaço intertubular seminífero variado com vasos sanguíneos, predominantemente evidentes; (5) no Grupo 1 o diâmetro médio dos túbulos seminíferos foi de 160,58µm e no Grupo 2 foi de 185,94µm, sendo os valores médios significantes entre si; (6) a altura média do epitélio seminífero foi de 49,51µm para o Grupo 1 e de 63,29µm para o Grupo 2, estaticamente significantes; (7) os maiores valores mensurados foram obtidos para os gatos do Grupo 2, por serem gatos adultos e portanto com os órgãos reprodutores funcionais.

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The failure of facial prostheses is caused by limitations in the properties of existing materials, especially the biocompatibility. This study aimed to evaluate the biocompatibility of maxillofacial silicones in subcutaneous tissue of rats. Thirty Wistar rats received subcutaneous implants of 3 maxillofacial silicone elastomers (LIM 6050, MDX 4-4210, and industrial Silastic 732 RTV). A histomorphometric evaluation was conducted to analyze the biocompatibility of the implants. Eight areas of 60.11 mm(2) from the surgical pieces were analyzed. Mesenchymal cells, eosinophils, and foreign-body giant cells were counted. Data were submitted to analysis of variance and Tukey test. Initially, all implanted materials exhibited an acceptable tissue inflammatory response, with tissue reactions varying from light to moderate. Afterward, a fibrous capsule around the silicone was observed. The silicones used in the current study presented biocompatibility and can be used for implantation in both medical and dental areas. Their prosthetic indication is conditioned to their physical properties. Solid silicone is easier to adapt and does not suffer apparent modifications inside the tissues.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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We report a rare heterotopic gastrointestinal cyst located in the right submandibular/submental area with histopathologic features that included portions resembling a dermoid cyst. Some theories of pathogenesis are discussed, and an origin of this lesion in entrapped undifferentiated endodermal cells is suggested.

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We have developed a biodegradable composite scaffold for bone tissue engineering applications with a pore size and interconnecting macroporosity similar to those of human trabecular bone. The scaffold is fabricated by a process of particle leaching and phase inversion from poly(lactide-co-glycolide) (PLGA) and two calcium phosphate (CaP) phases both of which are resorbable by osteoclasts; the first a particulate within the polymer structure and the second a thin ubiquitous coating. The 3-5 mu m thick osteoconductive surface CaP abrogates the putative foreign body giant cell response to the underlying polymer, while the internal CaP phase provides dimensional stability in an otherwise highly compliant structure. The scaffold may be used as a biomaterial alone, as a carrier for cells or a three-phase drug delivery device. Due to the highly interconnected macroporosity ranging from 81% to 91%, with macropores of 0.8 similar to 1.8 mm, and an ability to wick up blood, the scaffold acts as both a clot-retention device and an osteoconductive support for host bone growth. As a cell delivery vehicle, the scaffold can be first seeded with human mesenchymal cells which can then contribute to bone formation in orthotopic implantation sites, as we show in immune-compromised animal hosts. We have also employed this scaffold in both lithomorph and particulate forms in human patients to maintain alveolar bone height following tooth extraction, and augment alveolar bone height through standard sinus lift approaches. We provide a clinical case report of both of these applications; and we show that the scaffold served to regenerate sufficient bone tissue in the wound site to provide a sound foundation for dental implant placement. At the time of writing, such implants have been in occlusal function for periods of up to 3 years in sites regenerated through the use of the scaffold.

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To study the histogenesis of spindle and epithelioid cell tumors of gastrointestinal tract we evaluated ten cases of gastrointestinal stromal tumors (GIST) previously classified as leiomyomas (6 cases) and leiomyosarcomas (4 cases). The cases were studied by morphological and immunohistochemistry procedures with search of three markers: muscle specific actin (HHF-35), vimentin and S-100 protein. All tumors showed vimentin positivity. Muscle differentiation was demonstrated in three cases (33.3%), all of them benign. One tumor, in small intestine, displayed S-100 protein positivity. The results showed that the GIST represent a heterogeneous group of tumors, most of which consist of primitive mesenchymal cells.

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Tissue repair is an integration of dynamic interactive processes that involves soluble mediators, blood components, production of extra-cellular matrix and mesenchymal cells. Many studies involving the use of LLLT shows that the healing process is favored by such therapy. The aim of this work was to evaluate, through histological analysis, the tissue effects of cutaneous wounds submitted to different intensities and a same irradiation dose with lasers in λ670 or λ685nm. Eighteen animals were divided in two experimental groups according to wavelength used (λ670 or λ685nm). Each one of these groups was divided still in three subgroups of three animals each, related to the intensity of applied irradiation (2, 15 or 25mW). Twelve animals acted as untreated controls and were not irradiated. The irradiation was carried out during seven days. The animals were sacrificed eight days after surgery. The specimens were removed, kept in 4% formaldehyde for 24 hours, routinely prepared to wax, stained with H&E and analyzed under light microscopy. The histological characteristics observed, so much in the irradiated animals, as in the control, they are indicative of a substitution repair process, however, the LLLT modulatory positive effect was observed, in the healing process, mainly associate to the use of the shorter wavelength and low power. The results of the present study indicate that LLLT improves cutaneous wound repair and best results are achieved when higher potencies associated to short wavelengths or lower potencies associated to higher wavelengths are used.

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The morphological evolution of the epididymal duct of guinea pigs (Cavia porcellus, L.) was studied on 10, 20, 30, 45, 60, 70, 90 and 100 days of age, being complex, which is due to the proper differentiation postnatal in the epididymal epithelium. Thus, it was observed that the initial segment of the epididymis reveals an increase of epithelial height corresponding to the average height of the main tubular epithelium cells, generally progressive after 45 days of age. The epithelial height in the middle segment were higher in younger stages (10 to 45 days) than in the prepubertal age (60 days), and have a decrease among 70 to 100 days of age. The ductular terminal segment starts a gradual decrease of the epithelial heights from puberal age (70 days), until adult age (90 to 100 days). In addition, this segment showed epithelial waviness that disappeared after 70 days of age, when the lumen fills it with sperm and cellular exfoliation. The cell types of the epididymal tubular epithelium, principal cells, basal cells and apical cells, were observed in all ages. In the epididymis of very young animals, there was a predominance of undifferentiated columnar cells. After 20 days of age, there was natural prevalence of the principal cells on other cell types, what is a feature similar to other mammals.

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Objective: To study the early sequential stages of osseointegration at implants installed in alveolar bony. Materials and methods: In 12 Labrador dogs, all mandibular premolars and first molars were extracted bilaterally. After 3 months of healing, full-thickness flaps were elevated in the edentulous region of the right side of the mandible. Implants were installed, and the flaps were sutured to allow a fully submerged healing. The timing of the installations in the left side of the mandible and of sacrifices were performed with a schedule that various observation periods to sacrifice from 5, 10, 20, and 30 days were available so that n = 6 was obtained per each healing period. Ground sections were prepared and analyzed. Results: Newly formed bone in contact with the implant surface was found after 10 days of healing and the percentage increased up to 50% after 1 month of healing. A higher percentage was found in the trabecular compared with the cortical bony compartment. Old bone decreased by about 50% during healing, being still present after 1 month (16%). The proportions of bone debris and bone particles were at 27% after 5 days and decreased during healing to 6% after 1 month. Conclusion: Osseointegration (new bone-to-implant contact) developed at various rates for cortical and trabecular compartments, respectively. In the trabecular region, mesenchymal cells were identified, subsequently developing into new bone in contact with the implant surface. In the cortical compartment, however, resorptive processes were observed throughout all periods of healing. The proportion of newly formed bone percentage was lower compared with that of the trabecular area. Old bone was still present after 1 month of healing in both compartments. Bone debris and small bone particles appeared to be involved in initial bone formation. © 2013 John Wiley & Sons A/S.

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Breast implants are medical devices that are used to augment breast size or to reconstruct the breast following mastectomy or to correct a congenital abnormality. Breast implants consist of a silicone outer shell and a filler (most commonly silicone gel or saline). Approximately 5 to 10 million women worldwide have breast implants. Histomorphometric study to evaluate the biological tissue compatibility of silicone implants suitable for plastic surgery and the adverse effects and risks of this material. Thirty Wistar white rats received subcutaneous implants and the revestiment of silicone gel Silimed ®®, and randomized into six groups of five animals each, according to the type of implanted material and the time of sacrifice. Eight areas of 60.11mm2 corresponding to the obtained surgical pieces were analyzed, counting mesenchymal cells, eosinophils, and foreign body giant cells, observing an acceptable biocompatibility in all implants, for subsequent statistical analysis by Tukey test. Silicone gel showed inflammation slightly greater than for other groups, with tissue reactions varying from light to moderate, whose result was the formation of a fibrous capsule around the material, recognized by the organism as a foreign body. Despite frequent local complications and adverse outcomes, this research showed that the silicone and top layer presented an acceptable chronic inflammatory reaction, which did not significantly differ from the control group. In general, it is possible to affirm that silicone gel had acceptable levels of biocompatibility, confirmed the rare presence of foreign body giant cells, and when of the rupture, formed a fibrous capsule around the material, separating the material of the organism. © AVICENA 2013.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)