Thesis (Ph.D. (Biochemistry))--Mahidol University, 1984.

Diss. (sammanfattning) Umeå : Univ., 2004. / Härtill 4 uppsatser.

Thesis (Ph.D. in Toxicology) -- University of Colorado at Denver and Health Sciences Center, 2005. / Typescript. Includes bibliographical references (leaves 128-138).

Thesis (Ph.D.) -- University of Texas Southwestern Medical Center at Dallas, 2006. / Not embargoed. Vita. Bibliography: 129-137.

Rupture of the anterior cruciate ligament (ACL) of the knee leads to chronic joint instability and reduced range of motion while the long term results are marred by a high prevalence of degenerative joint disease especially osteoarthritis. Bundles of collagen threads have been widely investigated for the repair of torn ACL, but are limited by insufficient tissue ingrowth to repopulate and completely regenerate these grafts. We have developed a novel in vitro method of characterizing fiber-based thread matrices by probing their ability to promote tissue ingrowth from a wound margin as a measure of their ability to promote repopulation and regeneration. This method is useful in the optimization of thread scaffolds, and is sensitive enough to distinguish between subtle variations in biopolymer chemistry and organization. Furthermore, this method was used to characterize the effects of crosslinking on the cell outgrowth and correlated the findings with the mechanical properties of collagen threads. The results suggest that crosslinking is required to achieve sufficient mechanical properties for high stress applications such as ACL replacement, but regardless of technique, crosslinking attenuated the cell outgrowth properties of the threads. To improve the regenerative capacity of these scaffolds, novel fibrin microthread matrices were developed with a similar morphology to collagen threads and sufficient mechanical strength to be incorporated in composite thread scaffold systems. These fibrin microthreads were loaded with FGF-2, a potent mitogen and chemotactic agent that works synergistically with fibrin in regulating cell signaling and gene expression. Increases in fibroblast migration and proliferation in FGF-2-loaded fibrin threads were successfully demonstrated with the concomitant promotion of oriented, aligned, spindle-like fibroblast morphology. These results suggest that fibrin-FGF-2 microthreads have distinct advantages as a biomaterial for the rapid regeneration of injured tissues such as the ACL.

Submitted by JULIANA ROSA LUIZ ALONSO null (ju29alonso@hotmail.com) on 2016-05-02T19:21:59Z No. of bitstreams: 1 Versão Final_Dissertação_Juliana Alonso.pdf: 3284684 bytes, checksum: 5cf89df8ddd554ca35ba036626ed5bdb (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-04T18:51:25Z (GMT) No. of bitstreams: 1 alonso_jrl_me_arafo.pdf: 3284684 bytes, checksum: 5cf89df8ddd554ca35ba036626ed5bdb (MD5) / Made available in DSpace on 2016-05-04T18:51:25Z (GMT). No. of bitstreams: 1 alonso_jrl_me_arafo.pdf: 3284684 bytes, checksum: 5cf89df8ddd554ca35ba036626ed5bdb (MD5) Previous issue date: 2016-04-06 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A estabilidade da união resina-dentina pode ser melhorada pelo uso de agentes promotores de ligações cruzadas (cross-linkers). Todavia, existe pouca informação quanto ao desempenho desses agentes em dentina radicular. Portanto, o objetivo do presente estudo foi avaliar o efeito de três cross-linkers na atividade proteolítica e na resistência da união cimento resinoso-dentina radicular. Raízes unirradiculares foram obtidas de pré-molares humanos (n=48). Após tratamento endodôntico, essas raízes foram distribuídas em 4 grupos (n=12): água deionizada (controle), carbodiimida (EDC) 0,5 mol/L, proantocianidina (PA) 5% ou glutaraldeído (GD) 5%. Decorridas 24h do tratamento com esses agentes e da cimentação de pinos de fibra de vidro com cimento resinoso, as raízes foram seccionadas transversalmente para a obtenção de espécimes com 1 mm de espessura, das regiões cervical, média e apical. Nove raízes por grupo foram utilizadas para o ensaio mecânico de extrusão e três para determinação da atividade proteolítica dentinária, por meio de zimografia in situ. Os dados de resistência de união (RU) foram submetidos aos testes de ANOVA e Tukey e a existência de associação entre o tipo de fratura e as variáveis independentes do estudo foi determinada pelo teste de qui-quadrado (2) (=0,05). Nenhum dos cross-linkers afetou a RU imediata. GD aumentou esses valores significativamente em comparação à PA, mas não ao controle. Houve redução significante da RU do terço cervical para o apical, exceto para o grupo PA. Aumento na porcentagem de fraturas adesivas entre o pino de fibra de vidro e o cimento resinoso foi observado para os grupos EDC e GD, em relação ao grupo controle, enquanto, para PA, houve aumento de fraturas adesivas entre o cimento resinoso e a dentina. Foi observada grande atividade gelatinolítica no grupo controle, a qual foi reduzida por todos os cross-linkers . Em conclusão, além de não interferirem negativamente na RU imediata, os cross-linkers reduziram a atividade proteolítica na camada híbrida da união cimento resinoso-dentina radicular. / The resin-dentin bond stability can be improved by the use of cross-linkers. However, only scarce information is available as to the performance of these agents on root dentin. Therefore, the aim of this study was to evaluate the effect of three cross-linkers on the proteolytic activity of root dentin and on the bond strength of resin-based cement-root dentin interfaces. Single canal roots were obtained from human premolars (n=48). After endodontic treatment, they were randomly divided into four groups: deionized water (control), 0.5 mol/L carbodiimide (EDC), 5% proanthocyanidin (PA) or 5% glutaraldehyde (GD). After 24h from dentin treatment with the cross-linkers and the cementation of a fiber post with a resin-based cement, the roots were transversally sectioned to obtain 1 mm-thick specimens, from the cervical, mid and apical areas. Nine roots per group were used for the push-out test and three for determining the proteolytic activity of the root dentin by in situ zymography. Bond strength data were submitted to ANOVA and Tukey tests and the existence of an association between the type of fracture and the independent variables of the study was determined by chi-square test (=0.05). None of the cross-linkers affected the bond strength. GD increased bond strength compared to PA, but both were similar to the control. Significant reduction in bond strength was observed between the cervical and the apical root thirds. Increase in the percentage of adhesive fractures between the glass fiber post and resin cement was observed for EDC and GD groups, in comparison with the control group, while for PA, an increase of adhesive fractures between the resin cement and dentin was observed. Intense gelatinolytic activity was seen in the control group which was remarkably reduced in the cross-linker-treated groups. In conclusion, besides not interfering with bond strength, the cross-linkers reduced the proteolytic activity in the hybrid layers of the resin cement-root dentin bond. / FAPESP: 2014/10183-8

Orientador: Josimeri Hebling / Resumo: A estabilidade da união resina-dentina pode ser melhorada pelo uso de agentes promotores de ligações cruzadas (cross-linkers). Todavia, existe pouca informação quanto ao desempenho desses agentes em dentina radicular. Portanto, o objetivo do presente estudo foi avaliar o efeito de três cross-linkers na atividade proteolítica e na resistência da união cimento resinoso-dentina radicular. Raízes unirradiculares foram obtidas de pré-molares humanos (n=48). Após tratamento endodôntico, essas raízes foram distribuídas em 4 grupos (n=12): água deionizada (controle), carbodiimida (EDC) 0,5 mol/L, proantocianidina (PA) 5% ou glutaraldeído (GD) 5%. Decorridas 24h do tratamento com esses agentes e da cimentação de pinos de fibra de vidro com cimento resinoso, as raízes foram seccionadas transversalmente para a obtenção de espécimes com 1 mm de espessura, das regiões cervical, média e apical. Nove raízes por grupo foram utilizadas para o ensaio mecânico de extrusão e três para determinação da atividade proteolítica dentinária, por meio de zimografia in situ. Os dados de resistência de união (RU) foram submetidos aos testes de ANOVA e Tukey e a existência de associação entre o tipo de fratura e as variáveis independentes do estudo foi determinada pelo teste de qui-quadrado (2) (=0,05). Nenhum dos cross-linkers afetou a RU imediata. GD aumentou esses valores significativamente em comparação à PA, mas não ao controle. Houve redução significante da RU do terço cervical para o apical, excet... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The resin-dentin bond stability can be improved by the use of cross-linkers. However, only scarce information is available as to the performance of these agents on root dentin. Therefore, the aim of this study was to evaluate the effect of three cross-linkers on the proteolytic activity of root dentin and on the bond strength of resin-based cement-root dentin interfaces. Single canal roots were obtained from human premolars (n=48). After endodontic treatment, they were randomly divided into four groups: deionized water (control), 0.5 mol/L carbodiimide (EDC), 5% proanthocyanidin (PA) or 5% glutaraldehyde (GD). After 24h from dentin treatment with the cross-linkers and the cementation of a fiber post with a resin-based cement, the roots were transversally sectioned to obtain 1 mm-thick specimens, from the cervical, mid and apical areas. Nine roots per group were used for the push-out test and three for determining the proteolytic activity of the root dentin by in situ zymography. Bond strength data were submitted to ANOVA and Tukey tests and the existence of an association between the type of fracture and the independent variables of the study was determined by chi-square test (=0.05). None of the cross-linkers affected the bond strength. GD increased bond strength compared to PA, but both were similar to the control. Significant reduction in bond strength was observed between the cervical and the apical root thirds. Increase in the percentage of adhesive fractures between th... (Complete abstract click electronic access below) / Mestre

Orientador: Josimeri Hebling / Resumo: Objetivo: Investigar a citotoxicidade transdentinária da acroleína (ACR) sobre células pulpares e a resistência máxima à tração (RMT) da matriz dentinária e resistência da união (RU) resina-dentina após a biomodificação do colágeno dentinário por esse agente promotor de ligações cruzadas. Métodos: Discos de dentina (0,4 mm de espessura) foram obtidos de molares humanos hígidos e adaptados em câmaras pulpares artificiais. Células MDPC-23 foram semeadas na superfície pulpar desses discos e a superfície oclusal foi condicionada com ácido fosfórico por 15s. Sobre a dentina condicionada foi aplicado (n=9): água deionizada (controle), ACR 0,02%, 0,01%, 0,005%, glutaraldeído 5% (GD) ou peróxido de hidrogênio 3%. Após 60s, a superfície foi lavada e as câmaras foram incubadas por 24h. Foi avaliada a viabilidade das MDPC-23 (alamarBlue) aderidas na parede pulpar dos discos e os extratos foram aplicados em novas MDPC-23 e HDPCs (células da polpa dental humana) cultivadas em placas de cultura. Após 24h, essas células foram avaliadas quanto a viabilidade, atividade de fosfatase alcalina (ensaio da timolftaleína), presença de nódulos de mineralização (Alizarin red) e expressão gênica de ALPL, DSPP, MMP2, MMP9 e IL1B (PCRq). Vinte cinco molares adicionais foram seccionados para obter espécimes de dentina (n=50) que foram completamente desmineralizados com ácido fosfórico por 24h. Os espécimes de matriz dentinária foram tratados por 60s com: água, ACR 0,02%, 0,01%, 0,005% ou GD 5% e submetid... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Objective: To investigate the transdentinal cytotoxicity of acrolein (ACR) on pulp cells, as well as the ultimate tensile strength (UTS) of the dentin matrix, and the strength of resin-dentin bonds after dentin collagen biomodification with this cross-linker. Methods: Dentin disks (0.4 mm thick) were cut from sound human molars and adapted in artificial pulp chambers. MDPC-23 were seeded on the pulpal side of the disks and the occlusal surface was etched with phosphoric acid for 15s. The etched dentin was treated with (n=9): deionized water (control), 0.02%, 0.01%, 0.005% ACR, 5% glutaraldehyde (GD), or 3% hydrogen peroxide. After 60s, the surface was rinsed, and the chambers were incubated for 24h. The viability of MDPC-23 cells seeded on the disk was assessed (alamarBlue) and the extracts were applied on new MDPC-23 and HDPCs (human dental pulp cells) seeded in culture plates. After 24h, the viability of the cells was investigated as well as the activity of alkaline phosphatase, presence of mineralized nodules (Alizarin red) and ALPL, DSPP, MMP2, MMP9 and IL1b gene expression (qPCR). Additional twenty-five human molars were sectioned to obtain dentin specimens (n=50) which were completely demineralized in 10% phosphoric acid for 24h. The specimens were treated for 60s with: water, 0.02%, 0.01%, 0.005% ACR or 5% GD, and then submitted to a mechanical test to determine the UBS. Finally, flat dentin surfaces prepared in 40 human molars were etched with phosphoric acid and trea... (Complete abstract click electronic access below) / Mestre

Thesis (Ph. D.)--University of South Florida, 2008. / Title from PDF of title page. Document formatted into pages; contains 133 pages. Includes vita. Includes bibliographical references.