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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Cell and tissue engineering of articular cartilage via regulation and alignment of primary chondrocyte using manipulated transforming growth factors and ECM proteins : effect of transforming growth factor-beta (TGF-β1, 2 and 3) on the biological regulation and wound repair of chondrocyte monolayers with and without presence of ECM proteins

Khaghani, Seyed Ali January 2010 (has links)
Articular cartilage is an avascular and flexible connective tissue found in joints. It produces a cushioning effect at the joints and provides low friction to protect the ends of the bones from wear and tear/damage. It has poor repair capacity and any injury can result pain and loss of mobility. One of the common forms of articular cartilage disease which has a huge impact on patient's life is arthritis. Research on cartilage cell/tissue engineering will help patients to improve their physical activity by replacing or treating the diseased/damaged cartilage tissue. Cartilage cell, called chondrocyte is embedded in the matrix (Lacunae) and has round shape in vivo. The in vitro monolayer culture of primary chondrocyte causes morphological change characterized as dedifferentiation. Transforming growth factor-beta (TGF-β), a cytokine superfamily, regulates cell function, including differentiation and proliferation. The effect of TGF-β1, 2, 3, and their manipulated forms in biological regulation of primary chondrocyte was investigated in this work. A novel method was developed to isolate and purify the primary chondrocytes from knee joint of neonate Sprague-Dawley rat, and the effect of some supplementations such as hyaluronic acid and antibiotics were also investigated to provide the most appropriate condition for in vitro culture of chondrocyte cells. Addition of 0.1mg/ml hyaluronic acid in chondrocyte culture media resulted an increase in primary chondrocyte proliferation and helped the cells to maintain chondrocytic morphology. TGF-β1, 2 and 3 caused chondrocytes to obtain fibroblastic phenotype, alongside an increase in apoptosis. The healing process of the wound closure assay of chondrocyte monolayers were slowed down by all three isoforms of TGF-β. All three types of TGF-β negatively affected the strength of chondrocyte adhesion. TGF-β1, 2 and 3 up regulated the expression of collagen type-II, but decreased synthesis of collagen type-I, Chondroitin sulfate glycoprotein, and laminin. They did not show any significant change in production of S-100 protein and fibronectin. TGF-β2, and 3 did not change expression of integrin-β1 (CD29), but TGF-β1 decreased the secretion of this adhesion protein. Manipulated TGF-β showed huge impact on formation of fibroblast like morphology of chondrocytes with chondrocytic phenotype. These isoforms also decreased the expression of laminin, chondroitin sulfate glycoprotein, and collagen type-I, but they increased production of collagen type-II and did not induce synthesis of fibronectin and S-100 protein. In addition, the strength of cell adhesion on solid surface was reduced by manipulated TGF-β. Only manipulated form of TGF-β1 and 2 could increase the proliferation rate. Manipulation of TGF-β did not up regulate the expression of integrin-β1 in planar culture system. The implications of this R&D work are that the manipulation of TGF-β by combination of TGF-β1, 2, and 3 can be utilized in production of superficial zone of cartilage and perichondrium. The collagen, fibronectin and hyaluronic acid could be recruited for the fabrication of a biodegradable scaffold that promotes chondrocyte growth for autologous chondrocyte implantation or for formation of cartilage.
12

Pressão exercida por sistema de pressão subatmosférica usado para fixação de enxerto de pele no tratamento de ferida cutânea. Estudo comparativo entre a tela de poliamida revestida de silicone e a tela de rayon como material de interposição / Pressure exerted by subatmospheric pressure system used for fixation of skin graft in the treatment of cutaneous wound. Comparative study between the silicon coated polyamide mesh and the rayon mesh as interposition material

Nogueira, Flávio Marques 10 August 2017 (has links)
Introdução: O tratamento de feridas cutâneas é difícil e está em contínua mudança. Entre as múltiplas terapias empregadas uma bastante usada é a enxertia de pele autógena. Sabe-se que o sucesso desta técnica depende, em parte, de haver condições adequadas no leito receptor e da qualidade do enxerto de pele retirado. Ainda, tão importante quanto a técnica cirúrgica, é o método para fixação do enxerto de pele ao leito e respectivo cuidado pós-operatório. Tem sido frequente o uso da terapia de feridas por pressão subatmosférica para fixação e integração de enxertos de pele no tratamento de feridas e habitualmente se coloca uma tela entre a esponja e o enxerto. Não há padronização na literatura médica sobre o que utilizar na tela. Objetivo: Comparar duas telas utilizadas e aferir o quanto cada uma interferia na pressão subatmosférica gerada pela unidade de aspiração contínua da terapia de feridas por pressão subatmosférica, por sua vez configurada para gerar um gradiente de pressão de 125 mmHg em relação à pressão atmosférica ambiente. Métodos: Foram realizados inicialmente dois estudos em voluntários normais para aferir a pressão subatmosférica sob a tela de rayon e sob a tela de poliamida, sobre a pele íntegra. Em um grupo de 30 indivíduos, as medidas foram feitas em tempos diferentes, montando-se e desmontando-se todo conjunto da esponja e de determinada tela sucessivas vezes. Em outro grupo de 15 indivíduos, as medidas foram feitas sequencialmente e com as sondas colocadas em conjunto, sendo metade da esponja sobre a tela de rayon e a outra metade sobre a tela de poliamida. A seguir, foi realizado estudo prospectivo com 30 pacientes portadores de feridas complexas, nos quais a terapia de feridas por pressão subatmosférica foi aplicada. Foram utilizadas tela de rayon e tela de poliamida em cada metade da área enxertada sobre a ferida. A pressão subatmosférica foi aferida sob cada tela e sob a esponja. Resultados: Os resultados mostraram diferença estatisticamente significativa entre as pressões sob as duas telas estudadas e em relação à pressão sob a esponja. Houve apenas uma perda completa de enxerto de pele. Conclusão: Concluiu-se que as diferentes telas estudadas reduziram a pressão subatmosférica gerada pelo dispositivo de aspiração contínua da Terapia de Feridas por Pressão Subatmosférica (TFPS) em comparação com a pressão medida como controle. / Introduction: Wound care is a difficult and ever changing field. Among many therapies employed, autogenous skin grafting is often used. The quality of the skin graft and appropriate conditions of the recipient bed are paramount for the success of this surgical procedure. Moreover, the method of skin graft fixation and postoperative care are as important as the surgical technique itself. Hence, subatmospheric pressure wound therapy has been used in the process of fixation and integration of skin grafts in the treatment of wounds when there is frequently a layer between the sponge and the graft. Thus far there has been no standardization in the medical literature as to which layer to use. Objective: Compare two layers and measure how much each one alone interfered in the subatmospheric pressure generated by the pump used in subatmospheric pressure wound therapy, when set to generate a pressure gradient of 125 mmHg in relation to the atmospheric pressure of the surroundings. Methods: Two pilot studies were, therefore, undertaken of normal volunteers to ascertain the subatmospheric pressure under the rayon layer, under the polyamide layer and under the sponge. In one pilot study, of a total of 30 individuals, their measurements were taken in different moments and the setting was mounted and unmounted three times. In another, of 15 individuals, the measurements were collected within just one setting, as half of the sponge had rayon underlying it and the other half had polyamide beneath it. Therefore another prospective study was undertaken of 30 patients bearers of complex wounds in which both the rayon and the polyamide layer was used for each half of the skin grafted area The subatmospheric pressure measured under each layer and directly under the sponge (control measure) was assessed. Results: The results showed statistically significant differences between the pressure measured on the two layers studied and the pressure measured under the sponge. There was only one total skin graft loss. Conclusion: In conclusion, it was found that the different layers studied did reduce the subatmospheric pressure generated by the pump used in subatmospheric pressure wound therapy as compared with the respective control measure.
13

Pressão exercida por sistema de pressão subatmosférica usado para fixação de enxerto de pele no tratamento de ferida cutânea. Estudo comparativo entre a tela de poliamida revestida de silicone e a tela de rayon como material de interposição / Pressure exerted by subatmospheric pressure system used for fixation of skin graft in the treatment of cutaneous wound. Comparative study between the silicon coated polyamide mesh and the rayon mesh as interposition material

Flávio Marques Nogueira 10 August 2017 (has links)
Introdução: O tratamento de feridas cutâneas é difícil e está em contínua mudança. Entre as múltiplas terapias empregadas uma bastante usada é a enxertia de pele autógena. Sabe-se que o sucesso desta técnica depende, em parte, de haver condições adequadas no leito receptor e da qualidade do enxerto de pele retirado. Ainda, tão importante quanto a técnica cirúrgica, é o método para fixação do enxerto de pele ao leito e respectivo cuidado pós-operatório. Tem sido frequente o uso da terapia de feridas por pressão subatmosférica para fixação e integração de enxertos de pele no tratamento de feridas e habitualmente se coloca uma tela entre a esponja e o enxerto. Não há padronização na literatura médica sobre o que utilizar na tela. Objetivo: Comparar duas telas utilizadas e aferir o quanto cada uma interferia na pressão subatmosférica gerada pela unidade de aspiração contínua da terapia de feridas por pressão subatmosférica, por sua vez configurada para gerar um gradiente de pressão de 125 mmHg em relação à pressão atmosférica ambiente. Métodos: Foram realizados inicialmente dois estudos em voluntários normais para aferir a pressão subatmosférica sob a tela de rayon e sob a tela de poliamida, sobre a pele íntegra. Em um grupo de 30 indivíduos, as medidas foram feitas em tempos diferentes, montando-se e desmontando-se todo conjunto da esponja e de determinada tela sucessivas vezes. Em outro grupo de 15 indivíduos, as medidas foram feitas sequencialmente e com as sondas colocadas em conjunto, sendo metade da esponja sobre a tela de rayon e a outra metade sobre a tela de poliamida. A seguir, foi realizado estudo prospectivo com 30 pacientes portadores de feridas complexas, nos quais a terapia de feridas por pressão subatmosférica foi aplicada. Foram utilizadas tela de rayon e tela de poliamida em cada metade da área enxertada sobre a ferida. A pressão subatmosférica foi aferida sob cada tela e sob a esponja. Resultados: Os resultados mostraram diferença estatisticamente significativa entre as pressões sob as duas telas estudadas e em relação à pressão sob a esponja. Houve apenas uma perda completa de enxerto de pele. Conclusão: Concluiu-se que as diferentes telas estudadas reduziram a pressão subatmosférica gerada pelo dispositivo de aspiração contínua da Terapia de Feridas por Pressão Subatmosférica (TFPS) em comparação com a pressão medida como controle. / Introduction: Wound care is a difficult and ever changing field. Among many therapies employed, autogenous skin grafting is often used. The quality of the skin graft and appropriate conditions of the recipient bed are paramount for the success of this surgical procedure. Moreover, the method of skin graft fixation and postoperative care are as important as the surgical technique itself. Hence, subatmospheric pressure wound therapy has been used in the process of fixation and integration of skin grafts in the treatment of wounds when there is frequently a layer between the sponge and the graft. Thus far there has been no standardization in the medical literature as to which layer to use. Objective: Compare two layers and measure how much each one alone interfered in the subatmospheric pressure generated by the pump used in subatmospheric pressure wound therapy, when set to generate a pressure gradient of 125 mmHg in relation to the atmospheric pressure of the surroundings. Methods: Two pilot studies were, therefore, undertaken of normal volunteers to ascertain the subatmospheric pressure under the rayon layer, under the polyamide layer and under the sponge. In one pilot study, of a total of 30 individuals, their measurements were taken in different moments and the setting was mounted and unmounted three times. In another, of 15 individuals, the measurements were collected within just one setting, as half of the sponge had rayon underlying it and the other half had polyamide beneath it. Therefore another prospective study was undertaken of 30 patients bearers of complex wounds in which both the rayon and the polyamide layer was used for each half of the skin grafted area The subatmospheric pressure measured under each layer and directly under the sponge (control measure) was assessed. Results: The results showed statistically significant differences between the pressure measured on the two layers studied and the pressure measured under the sponge. There was only one total skin graft loss. Conclusion: In conclusion, it was found that the different layers studied did reduce the subatmospheric pressure generated by the pump used in subatmospheric pressure wound therapy as compared with the respective control measure.
14

Cell and tissue engineering of articular cartilage via regulation and alignment of primary chondrocyte using manipulated transforming growth factors and ECM proteins. Effect of transforming growth factor-beta (TGF-¿1, 2 and 3) on the biological regulation and wound repair of chondrocyte monolayers with and without presence of ECM proteins.

Khaghani, Seyed A. January 2010 (has links)
Articular cartilage is an avascular and flexible connective tissue found in joints. It produces a cushioning effect at the joints and provides low friction to protect the ends of the bones from wear and tear/damage. It has poor repair capacity and any injury can result pain and loss of mobility. One of the common forms of articular cartilage disease which has a huge impact on patient¿s life is arthritis. Research on cartilage cell/tissue engineering will help patients to improve their physical activity by replacing or treating the diseased/damaged cartilage tissue. Cartilage cell, called chondrocyte is embedded in the matrix (Lacunae) and has round shape in vivo. The in vitro monolayer culture of primary chondrocyte causes morphological change characterized as dedifferentiation. Transforming growth factor-beta (TGF-¿), a cytokine superfamily, regulates cell function, including differentiation and proliferation. The effect of TGF-¿1, 2, 3, and their manipulated forms in biological regulation of primary chondrocyte was investigated in this work. A novel method was developed to isolate and purify the primary chondrocytes from knee joint of neonate Sprague-Dawley rat, and the effect of some supplementations such as hyaluronic acid and antibiotics were also investigated to provide the most appropriate condition for in vitro culture of chondrocyte cells. Addition of 0.1mg/ml hyaluronic acid in chondrocyte culture media resulted an increase in primary chondrocyte proliferation and helped the cells to maintain chondrocytic morphology. TGF-¿1, 2 and 3 caused chondrocytes to obtain fibroblastic phenotype, alongside an increase in apoptosis. The healing process of the wound closure assay of chondrocyte monolayers were slowed down by all three isoforms of TGF-¿. All three types of TGF-¿ negatively affected the strength of chondrocyte adhesion. TGF-¿1, 2 and 3 up regulated the expression of collagen type-II, but decreased synthesis of collagen type-I, Chondroitin sulfate glycoprotein, and laminin. They did not show any significant change in production of S-100 protein and fibronectin. TGF-¿2, and 3 did not change expression of integrin-¿1 (CD29), but TGF-¿1 decreased the secretion of this adhesion protein. Manipulated TGF-¿ showed huge impact on formation of fibroblast like morphology of chondrocytes with chondrocytic phenotype. These isoforms also decreased the expression of laminin, chondroitin sulfate glycoprotein, and collagen type-I, but they increased production of collagen type-II and did not induce synthesis of fibronectin and S-100 protein. In addition, the strength of cell adhesion on solid surface was reduced by manipulated TGF-¿. Only manipulated form of TGF-¿1 and 2 could increase the proliferation rate. Manipulation of TGF-¿ did not up regulate the expression of integrin-¿1in planar culture system. The implications of this R&D work are that the manipulation of TGF-¿ by combination of TGF-¿1, 2, and 3 can be utilized in production of superficial zone of cartilage and perichondrium. The collagen, fibronectin and hyaluronic acid could be recruited for the fabrication of a biodegradable scaffold that promotes chondrocyte growth for autologous chondrocyte implantation or for formation of cartilage.

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