Made available in DSpace on 2014-06-11T19:31:06Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T19:20:06Z : No. of bitstreams: 1 faria_pep_dr_araca.pdf: 1244848 bytes, checksum: 1c3d78205883be40533349acdfc5ffde (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A combinação de um fármaco fotossensível (FS) ativado por luz (vermelha, infravermelho ou ambas) forma uma das vertentes de aplicação da Terapia Fotodinâmica (TFD), que consiste na administração de um FS que posteriormente é ativado pela irradiação do LED ou Laser junto ao tecido, sendo que o FS ou a luz sozinhas, não apresentam citotoxicidade. O presente estudo teve por objetivos estabelecer o potencial regenerador do tecido ósseo para o reparo em calvária de coelho, utilizando três sistemas de liberação de drogas (DDS) de FS, estimulado pela combinação da fotobiomodulação de sistemas LED operando na faixa do visível e infravermelho. Foram utilizados 48 coelhos New Zealand White divididos em 3 grupos: Grupo LED 24/48 (dezoito coelhos) com aplicações de LED 24/48 horas após a cirurgia, Grupo LED 72/96 (dezoito coelhos) com aplicações de LED 72/96 horas após a cirurgia e Controle (doze coelhos) onde não houve aplicação de LED. Nos grupos experimentais foram realizadas 4 perfurações nas calvárias com preenchimento aleatoriamente de 1) Base em gel, 2) nanoemulsão carregada com FS, 3) lipossoma em gel com FS e 4) nanopartículas de albumina (BSA) carregada com FS. No grupo controle foram feitas duas perfurações, uma preenchida por osso autógeno e outra com coágulo. Dezesseis animais foram submetidos à eutanásia em cada tempo experimental: 5 dias, 10 dias e 20 dias. Lâminas histológicas foram feitas a partir dos defeitos e o osso neoformado foi mensurado. O uso de FS nos DDS não foi efetivo para abreviar o tempo de reparo ósseo em calvária de coelhos nos inervalos de tempo deste estudo / The combination between photosensitizer substances with laser or LED (light emitting diode) form the photodynamic therapy (PDT) basis that consists of photosensitivity drug activated by low frequency light. This mechanism is used in soft tissue healing process to improve the oxygen tension leading to a fast revascularization. The objective of this study was to evaluate the effects of photosensitivity drugs activated through LED on bone healing process. Fourty eight New Zealand White rabbits were underwent to four bicortical calvaria defects made by 6.0 mm trephine drill. The defects were randomly filled up with (1) Gel, (2) Nanoemulsion + photosensitizer drug, (3) Liposome + photosensitizer drug, (4) NPS (nanostructure polymeric system) + photosensitizer drug. After 24/48 hours or 72/96 hours a LED were applied on all the rabbits. Sixteen animals were sacrificed, respectively, at 5, 10 and 20 days after surgery. Histological slides were prepared from each experimental site for histomorphometry and histological analysis. Bone graft was significant higher bone level in all experimental time points.. At 10 days liposome showed higher bone level than Gel (p=0,0161). However on 20 days, no difference was detected between the materials. The use of photosensitizer drugs activated by LED demonstrated do not achieve the stimulate bone formation on later time points on thsi presente study

This is an original study to quantify and grade defect healing in a large animal cranial bone substitute model. The study of various therapies to heal cranial defects requires an appropriate ?critical? animal model. An experimental animal model should be analogous and recognizable as an appropriate challenge to human physiology. In addition, the defect must fail to heal unless treated with the tissue engineering therapy under study. Sheep as a large animal model was chosen because of its ability to tolerate creation of large skull defects analogous to clinical scenario, and its biology of healing as a high order mammal would be closer human beings. There is no agreement on the critical size limits for cranial defects. Various sizes have been termed "critical" in publications utilizing sheep. These ranged from 20-22mm. This study will investigate whether a 20mm defect is adequate. Bilateral circular cranial defects of 10, 20 and 25mm diameters were created in 12 adult sheep. Based on guided tissue engineering principles, defect protection was utilized to prevent in-growth of fibroblasts and other connective tissue cells from the surroundings. As bone tissue regeneration strategies usually involve osteoconduction element, an animal model that considered the defect protection role of osteoconduction would be more appropriate. Repopulation and regeneration of the defect was maximized as an added challenge Bioresorbable polylactic acid co-polymer mesh (MacroPoreTM) and Titanium mesh (TiMeshTM) was used as defect protection. The cranial defects were harvested at 8 and 16 weeks. The end-point analysis included Faxitron X-ray images, DEXA (Dual Energy X-ray Absorptiometry), and histology. The defects were graded to assess their ability to eventually heal. 10mm defects fully healed at 16 weeks. There was new bone formation spanning the entire defect seen on histology. 25mm defects were spanned by thin fibrous tissue only. There was variability in the healing potential of 20mm defect. Based on presence of bone islands within the defect, half of the 20mm defects demonstrated ability to heal while the other half actually had new bone spanning the defects on histology. Critical size cranial defect in sheep for the study of bone graft substitute has to be larger than 25mm diameter. The model is then utilized to study the use of Pro Osteon and AGF compared with the gold standard of autologous bone graft.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 117-191). Also available in print.

Thesis (MA)--University of Montana, 2009. / Contents viewed on January 14, 2010. Title from author supplied metadata. Includes bibliographical references.

Thesis (M.S.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains vii, 79 p. : ill. Includes abstract. Includes bibliographical references (p. 71-79).

Thesis (doctoral)--Copenhagen, 1981. / Includes bibliographical references (p. 163-171) and index.

Thesis (doctoral)--University of Göteborg, 1984. / Extra t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.A.)--Guo li Taiwan da xue. / Cover title. Bibliography: p. 256-259.

Thesis (M.S. in Mechanical Engineering)--Naval Postgraduate School, March 2003. / Thesis advisor(s): Young W. Kwon. Includes bibliographical references (p. 45). Also available online.

abstract / Biochemistry / Doctoral / Doctor of Philosophy