Patients who suffer from severe joint destruction caused by arthritis often undergo total joint arthroplasty (TJA). A major limitation of this treatment and common long-term complication is the development of aseptic loosening of the prosthesis in as many as 20% of patients. The current paradigm to explain aseptic loosening proposes that wear debris generated from the prosthesis initiates a macrophage-mediated inflammatory response by resident macrophages, leading to osteoclast activation and bone resorption at the implant interface. This can then lead to the development of a peri-prosthetic fracture. The principal aim of fracture healing is to restore the bone to its original form and strength. However, this ultimate goal can be altered if the healing is impaired. This impairment may be due to bone disease (osteoporosis) or even the introduction of a foreign material such as PE wear debris that could have migrated from the articulating surface to the fracture site. A standard closed unilateral fracture of the right femur was performed in both normal and oestrogen deficient rats following fixation with a k-wire. Ceridust (PE wear debris) was combined with hyaluronic acid and saline and injected directly into the fracture site. Femurs were assessed using radiographs, histology and immunohistochemistry. Histological analysis revealed that complete remodelling was achieved in all control groups by 6 weeks post-fracture with mechanical strength returning to normal values. The mechanical properties of the fractures were not influenced by the presence of PE wear debris in the dose and timing examined. Histology and immunohistochemistry however, did reveal a local effect of the presence of PE wear debris. The histology adjacent to the PE particles was inferior to the controls but did not manifest itself in a reduction in the mechanical properties except in the oestrogen deficient bone at 6 weeks post-fracture. The levels of MMP-1 and TNF-?? correlated to the presence of PE particles. In this thesis, I have shown the mechanism by which bone remodelling in fracture healing could be retarded due to the presence of PE wear debris, by increased matrix degradation in both normal and oestrogen deficient animals.

Patients who suffer from severe joint destruction caused by arthritis often undergo total joint arthroplasty (TJA). A major limitation of this treatment and common long-term complication is the development of aseptic loosening of the prosthesis in as many as 20% of patients. The current paradigm to explain aseptic loosening proposes that wear debris generated from the prosthesis initiates a macrophage-mediated inflammatory response by resident macrophages, leading to osteoclast activation and bone resorption at the implant interface. This can then lead to the development of a peri-prosthetic fracture. The principal aim of fracture healing is to restore the bone to its original form and strength. However, this ultimate goal can be altered if the healing is impaired. This impairment may be due to bone disease (osteoporosis) or even the introduction of a foreign material such as PE wear debris that could have migrated from the articulating surface to the fracture site. A standard closed unilateral fracture of the right femur was performed in both normal and oestrogen deficient rats following fixation with a k-wire. Ceridust (PE wear debris) was combined with hyaluronic acid and saline and injected directly into the fracture site. Femurs were assessed using radiographs, histology and immunohistochemistry. Histological analysis revealed that complete remodelling was achieved in all control groups by 6 weeks post-fracture with mechanical strength returning to normal values. The mechanical properties of the fractures were not influenced by the presence of PE wear debris in the dose and timing examined. Histology and immunohistochemistry however, did reveal a local effect of the presence of PE wear debris. The histology adjacent to the PE particles was inferior to the controls but did not manifest itself in a reduction in the mechanical properties except in the oestrogen deficient bone at 6 weeks post-fracture. The levels of MMP-1 and TNF-?? correlated to the presence of PE particles. In this thesis, I have shown the mechanism by which bone remodelling in fracture healing could be retarded due to the presence of PE wear debris, by increased matrix degradation in both normal and oestrogen deficient animals.

Siderophores are a series of important iron chelators secreted by many bacteria that normally have high affinity of iron ions and contain hydroxamate, catecholate and carboxylate and other ligand groups. These organic ligands play significant roles in bacterial metabolism: solubilising iron (III) from environments, enabling iron uptake and acting as a cell-signalling molecule to control gene expression. Recent observations of initial stages of Pseudomonas aeriginosa biofilm formation on metal oxides surfaces indicate that siderophores may also facilitate bacterial adhesion to metals. However, details of how siderophores interact with metal surfaces and the relationship of their chemical nature with bacterial adhesion were not fully understood. To test the generality of bacteria attachment to metals via siderophores, the adsorption behaviour of siderophores and their functional ligands groups on particle films of metal oxides were investigated with in-situ ATR-IR spectroscopy. In this study, nanoparticle films of titanium oxide, boehmite, iron oxide and chromium oxyhydroxide were prepared as substrates to simulate titanium, alumnium, stainless steel surface and more detailed work were carried out on titanium dioxide. Monohydroxamic acids (acetohydroxamic acid, N-methylformohydroxamic acid, N-methyl-acetohydroxamic acid and 1-hydroxy, 2-piperidone) and catechol and catechol-like (L-dopa and esculetin) ligands were selected as modelling compounds for the most frequently occured functional groups in natural siderophores. IR spectra of these ligands in aqueous solution and adsorbed on TiO₂ were obtained with a flowing cell system fit to a horizontal accessory by in situ ATR-IR spectroscopy and interpreted based on vibrational mode analysis with density function theory. Results show that all these ligands can form surface complexes with metal surfaces and possible adsorption modes of these molecules were discussed. The pH dependence of absorbance of IR absorption of these adsorbed ligands showed that most of the ligands exhibited maximium adsorption to TiO₂ at about pH 8, only N-methylformohydroxamic acid, 1-hydroxy, 2-piperidone groups having maximum absorption at pH~3 and pH~6. Infrared spectroscopic studies of adsorbed siderophores (desferroximme B, enterobactin and pyoverdine) were also carried out in variation of concentration and pH. Possible adsorption modes of these iron scavenger ligands on TiO₂ and other metal oxides were discussed. Results showed that all these ligands adsorbed on metal oxide surfaces and form surface complex via hydroxamate or catecholate lignd groups which confirm the generality of siderphore-metal bond formation. Siderophore based-bacterial adhesion to metals of was conducted with Pesudomonas aeruginosa and E. coli strains on titanium oxide and iron oxide films. These observations support that siderophore play a significant role in bacterial adhesion to metals. Further work needs to be carried out on the wider involvement of siderophores in bacterial adhesion initiation to metals and siderophore-mediated iron transport.

Made available in DSpace on 2014-06-11T19:22:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-25Bitstream added on 2014-06-13T19:27:11Z : No. of bitstreams: 1 soranzfilho_je_me_botfm.pdf: 1652118 bytes, checksum: 7a01edbccd06925523118f49c1d42b63 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Universidade Estadual Paulista (UNESP) / Alterações oculares, em especial a perda de volume nas cavidades evisceradas, promovem uma série de modificações ao paciente tanto funcional do órgão quanto psicológica e estética. Uma grande preocupação ao longo do tempo é a procura de um material que possa preencher o volume perdido de forma a dar um maior conforto no ponto de visto psicológico e estético ao paciente. Para contribuir nessa direção, esse trabalho teve como objetivo testar experimentalmente prótese de polietileno granulado de ultra-alto peso molecular, material de baixo custo, em órbitas de coelhos submetidos à evisceração cirúrgica em vários tempos experimentais, onde foram avaliados aspectos macroscópicos e microscópicos e de toxicidade sistêmica do material. Os resultados desse trabalho mostram que o material utilizado no implante de cavidade não apresenta alteração significativa nos parâmetros analisados quando comparados ao grupo controle. Sendo resultados bastante promissores indicando que o implante de polietileno poroso desenvolvido por uma indústria nacional tem alto potencial para se realizar testes em humanos / Ocular changes especially the loss of volume in eviscerated cavities promotes several modifications to patients – organ functioning and psychological and esthetical changes. A material that could replace the lost volume in order to guarantee to patients more psychological and esthetical comfort has long been worryingly searched. Contributing in this direction this work aimed at testing experimentally a prosthesis polyethylene granulate of ultra-high molecular weight made of a low cost material to be implanted in orbit of rabbits through surgical evisceration during several experimental times to assess macroscopic and microscopic aspects of systemic toxicity of the respective material. The results show that the material used for the implant of the prosthesis in the cavity does not present significant alteration in the analysed parameters when compared to the control group. Thus, we point with this study promising results indicating that the porous polyethylene implant developed by a national enterprise presents high potential to be tested in humans

Thesis (Ph. D.)--University of Alabama at Birmingham, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 1996. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Orientador: Cláudia Helena Pellizon / Banca: Silvana Artioli Schellini / Banca: Cláudia Valeria Seullner Brandão / Resumo: Alterações oculares, em especial a perda de volume nas cavidades evisceradas, promovem uma série de modificações ao paciente tanto funcional do órgão quanto psicológica e estética. Uma grande preocupação ao longo do tempo é a procura de um material que possa preencher o volume perdido de forma a dar um maior conforto no ponto de visto psicológico e estético ao paciente. Para contribuir nessa direção, esse trabalho teve como objetivo testar experimentalmente prótese de polietileno granulado de ultra-alto peso molecular, material de baixo custo, em órbitas de coelhos submetidos à evisceração cirúrgica em vários tempos experimentais, onde foram avaliados aspectos macroscópicos e microscópicos e de toxicidade sistêmica do material. Os resultados desse trabalho mostram que o material utilizado no implante de cavidade não apresenta alteração significativa nos parâmetros analisados quando comparados ao grupo controle. Sendo resultados bastante promissores indicando que o implante de polietileno poroso desenvolvido por uma indústria nacional tem alto potencial para se realizar testes em humanos / Abstract: Ocular changes especially the loss of volume in eviscerated cavities promotes several modifications to patients - organ functioning and psychological and esthetical changes. A material that could replace the lost volume in order to guarantee to patients more psychological and esthetical comfort has long been worryingly searched. Contributing in this direction this work aimed at testing experimentally a prosthesis polyethylene granulate of ultra-high molecular weight made of a low cost material to be implanted in orbit of rabbits through surgical evisceration during several experimental times to assess macroscopic and microscopic aspects of systemic toxicity of the respective material. The results show that the material used for the implant of the prosthesis in the cavity does not present significant alteration in the analysed parameters when compared to the control group. Thus, we point with this study promising results indicating that the porous polyethylene implant developed by a national enterprise presents high potential to be tested in humans / Mestre

Thesis (Ph. D.)--University of Alabama at Birmingham, 1998. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Alabama at Birmingham, 1998. / Includes bibliographical references.

Thesis (M.S.)--Mississippi State University. Department of Agricultural and Biological Engineering. / Title from title screen. Includes bibliographical references.