300 resultados para Experimental model


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

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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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OBJECTIVE: Investigation of standard intensities of physical exercise is important to better comprehend and develop rehabilitation programs for emphysema. We aimed to evaluate the effects of different intensities (moderate and high-intensity) of physical exercise on the development of a protease-induced (papain intratracheal instillation) emphysema in rats. METHODS: Male Wistar rats were randomly separated into five groups that received intratracheal instillation of papain solution or vehicle: (i) papain high intensity exercise, (ii) papain moderate exercise, (iii) saline high intensity exercise, (iv) saline sedentary and (v) papain sedentary. Forty days after intratracheal instillation, the exercise groups were submitted to an exercise-training protocol on a treadmill during 10 weeks, 5 days/week, at 0.9 km/h (Papain and saline high exercise), or at 0.6 km/h (papain moderate exercise).We measured respiratory system elastance and resistance, the collagen fiber lung parenchyma, and the pulmonary mean linear intercept. RESULTS: All animal groups that received papain instillation presented higher alveolar wall destruction compared to animals that received only saline solution. The papain high intensity exercise group presented higher values of mean linear intercept compared to emphysema groups that were trained at a moderate intensity or not submitted to exercise. CONCLUSION: High intensity exercise training worsened alveolar destruction in an experimental model of emphysema in rats when compared to moderate intensity exercise, or to no exercise.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Materiais estruturais utilizados no projeto de equipamentos e instalações industriais podem apresentar mudança de seu comportamento à fratura quando se varia a temperatura. Este tipo de comportamento caracteriza-se pela existência de uma curva de transição, onde 3 regiões ficam bem definidas: os patamares inferior e superior e a região de transição. Na região de transição, os resultados experimentais apresentam alto espalhamento e são bastante dependentes da geometria ensaiada. Para solucionar este problema, foi desenvolvido um modelo analítico experimental, que resultou na edição da norma ASTM E1921-97. O trabalho inclui um estudo da influência de diversas rotas de tratamentos térmicos aplicadas em um aço 4130 utilizado pela indústria aeronáutica, um aço de qualidade API utilizado pela indústria petrolífera e um aço da classe A516 atualmente utilizado pela indústria nacional de vasos de pressão, na microestrutura, propriedades mecânicas de tração e tenacidade à fratura. Os resultados mostraram que o aço 4130 A450, apresentou a melhor correlação entre resistência e tenacidade entre as microestruturas pesquisadas. Este comportamento deve estar associado a rota de tratamento térmico aplicada a esta condição. O tratamento de austêmpera possibilita a formação de bainita que, tradicionalmente é conhecida por apresentar elevados valores de tenacidade. O método proposto pela ASTM pode ser considerado viável para as diversas microestruturas pesquisadas ampliando a aplicação da metodologia que recomenda o ensaio apenas para aços ferríticos. No entanto, a metodologia da Curva Mestra em materiais tratados termicamente deve ser conduzida de forma a se estabelecer parâmetros que considerem as modificações microestruturais sofridas pelo material.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The canine species has been used as an experimental model for preservation of endangered species. Biotechnologies of reproduction, such as in vitro maturation (IVM), have been used to meet this objective. Several protocols for in vitro embryo production (IVEP) in swine and bovine species have been adapted for canids. However, the highest rate reported for in vitro maturation in canids is only 39%, which is still lower than those in other species. Therefore, current research on assisted reproduction in canids have focused on several IVM protocols, including the addition of proteins, hormones, meiosis inhibitors, growth factors and antioxidants to the maturation media and the determination of suitable timing for culture, so that variables involved in the process can be fine-tuned. This review has the main objective of describing major developments and limitations in the process of oocyte maturation in bitches.

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Pós-graduação em Cirurgia Veterinária - FCAV

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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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Pós-graduação em Medicina Veterinária - FMVZ

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The importance of this study is based on the need to obtain simple and efficient in vitro models to predict the in vivo toxicity of cosmetics, aiming not to use animals as experimental model. Here, we proposed the use of HepG2 cells, which are widely applied to simulate the hepatic function of the human organism in vitro. This cell line was chose since recent studies have shown that the liver is potentially the most frequently targeted organ by cosmetic ingredients, and beyond that, considering the widely application of in vitro assays to test the cutaneous permeation of cosmetic products, including the assays applying modified Franz cells, this technique becomes indispensable. Three different cosmetic active substances were used, and the toxicity to HepG2 cells was assessed by the MTT method. The treatment with hyaluronic acid showed no toxicity to HepG2 cells. Treating the cells with P. guajava L. extract were verified that increasing the amount of the extract in the media, the cellular viability decreased, and finally, the treatment of alpha-lipoic acid showed a cytoprotective effect in relation to the treatment with propylene glycol. The study demonstrated the suitability in using HepG2 cells to assess the safety of cosmetic active substances, helping in the prediction of if the substance could be hepatotoxic if could reach the bloodstream

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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)