Thesis (Ph. D.)--University of Virginia, 1999. / Spine title: X-ray structure of PAF acetylhydrolase. Includes bibliographical references (p. 161-175). Also available online through Digital Dissertations.

Thesis (M.Med.Sc.)--University of Hong Kong, 1999. / Includes bibliographical references (leaves 53-63). Also available in print.

Zugl.: Berlin ; Freie Universiẗat, Diss., 2008.

Thesis (M. Phil.)--University of Hong Kong, 2005. / Title proper from title frame. Also available in printed format.

Universiẗat, Diss., 2003--Jena.

Universiẗat, Diss., 2002--Essen.

Resumo: Lesões na cartilagem articular representam um desafio para a Medicina Veterinária devido ao limitado potencial intrínseco de reparação. As células tronco mesenquimais (CTM) e o plasma rico em plaquetas (PRP) vêm sendo utilizados na reparação condral pela capacidade de imunomodulação, quimiotaxia, por diminuir a degradação da cartilagem articular e exercer efeito anti-inflamatório. Esse trabalho estudou a eficácia das CTM e do PRP no tratamento de lesões condrais articulares, experimentalmente induzidas em equinos, apresentando os benefícios e os principais obstáculos encontrados na aplicação clínica e cirúrgica de equinos. Para isso, foi induzida uma lesão condral, na tróclea medial femoral dos dois membros pélvicos de oito animais. Após 30 dias da indução dessa lesão os animais, divididos em quatro grupos, receberam os tratamentos propostos: com CTM (Grupo 1); PRP (Grupo 2); CTM e PRP (Grupo 3) e um controle sem tratamento (Grupo 4). As avaliações dos parâmetros clínico-laboratoriais foram realizadas antes da indução da lesão (T-0), quinzenalmente até 120 dias e aos 150 dias (T-150). Avaliações macroscópicas, histopatológicas e histoquímicas foram realizadas em T-0 e T- 150. Pôde-se observar discreta melhora clínico-laboratorial dos grupos tratados quando comparados ao grupo controle. Os exames macroscópicos, histopatológicos e histoquímicos revelaram um melhor tecido de reparação nos grupos tratados, principalmente nos grupos 2 e 3. Sendo assim, o implante autólogo de CTM e do PRP apresentou efeitos benéficos no tratamento de lesões condrais, experimentalmente induzidas em equinos / Abstract: Articular cartilage defects represent a challenge for Veterinary Medicine due to the limited intrinsic potential of repair. Mesenchymal Stem Cells (MSC) and Platelet-Rich Plasma (PRP) have been used in cartilage repair to promote immunomodulation, chemotaxis, to decrease the degradation of articular cartilage and to take antiinflammatory effect. This work aims to study the use of intralesional MSC and the PRP in the treatment of articular cartilage defects induced experimentally in horses, noting the benefits and challenges encountered in implementing clinical-surgical in horses. For this purpose, both patellofemoral joints of eight animals were approached by arthroscopic surgery to perform a cartilage defect, on the medial femoral trochlea. After 30 days of induction the animals, who were divided into four groups, received treatment with: MSC (Group 1), PRP (Group 2), MSC and PRP (Group 3) and a control without treatment (Group 4). The clinical and laboratory assessments were performed every 15 days in 120 days, with last analysis in day 150. The macroscopic and morphologic analyses were performed at 0 and 150 day. There were clinical and laboratory improvement in the treated groups compared with control group. The macroscopic and morphological analysis showed a better tissue repair in the treated groups, mainly in groups 2 and 3. Thus, the implantation of autologous MSC and PRP showed beneficial effects in the treatment of chondral lesions, experimentally induced in horses / Orientador: Ana Liz Garcia Alves / Coorientador: Marcos Jun Watanabe / Banca: Ligia Souza Lima Silveira da Mota / Banca: Raquel Yvone Arantes Baccarin / Mestre

Human adult mesenchymal stem cells (MSCs) derived from bone marrow have the capacity to self-renew and to differentiate into a variety of cells and tissues. They can leave their niche to migrate to remote tissues where they play a critical role in angiogenesis, wound repair and tissue regeneration. A major goal in adult stem cell research is to define how MSC fate is controlled by the pericellular extracellular matrix (ECM) and soluble factors that largely constitute their tissue-specific niches. Defining crucial regulatory signals that control the fate and function of MSCs in vitro will contribute to the development of therapeutic strategies to improve tissue regeneration. The objective of this study was to investigate the molecular relationships between cell-ECM integrin receptors and platelet-derived growth factor receptor (PDGFR) tyrosine kinases, which are crucial in modulating MSC expansion, recruitment, and differentiation towards a number of different cell lineages. This study reports that ECM-directed cross-talk between PDGFR-β and alpha5β1 integrin controls the migration of MSCs. Cell adhesion to fibronectin induced integrin alpha5β1-dependent phosphorylation of PDGFR-β in the absence of growth factor stimulation. Phosphorylated PDGFR-β co-immunoprecipitated with integrin alpha5 and co-localised with alpha5β1 in a transient tidemark of focal adhesions. Adhesion to fibronectin also strongly potentiated platelet-derived growth factor (PDGF)-BB-stimulated PDGFR-β phosphorylation, in an alpha5β1-dependent manner. PDGFR-β-activated phosphatidylinositol 3 ́-kinase (PI3-kinase) and Akt activity, actin reorganisation and cell migration were all regulated by fibronectin engagement of alpha5β1 integrin. This synergistic relationship between integrin alpha5β1 and PDGFR-β is a fundamental determinant of mesenchymal cell migration. Thus, fibronectin-rich matrices can prime PDGFR-β to recruit mesenchymal cells at sites of tissue remodelling.

Magister Chirurgiae Dentium (MChD) / Wound healing is a complex process characterised by the repair and reconstitution of lost or damaged tissue. By the mid 1990s, several methods were proposed to enhance wound healing of surgical sites by introducing high concentrations of human platelets to these areas. In the early 21st century, Choukroun et al (2006b) introduced a new type of platelet concentrate that was devoid of any additives, and required no specialised equipment for its production. This concentrate was termed Platelet-rich fibrin (PRF) and although various aspects of this biomaterial had been studied, very little is currently known about its storage properties. Aim: To determine whether storage time had a significant effect on the platelet concentration of Choukroun’s PRF Method: A total of 30 patients were enrolled into the study. Three blood samples of 10ml each were drawn from each patient. Two of the blood samples (Group A and Group B) were centrifuged to form PRF. The third sample was used to measure the baseline blood platelet concentration and was therefore not centrifuged. After PRF had formed in both test groups, it was removed from the test tubes at 2 different times i.e. immediately after centrifuge (Group A) or after 60 min of storage in the blood collecting tube (Group B). The remaining blood was then tested for platelet concentration and compared to each other and the baseline reading. Results: 14 males and 16 females participated in the study (average age 41.7 years). A mean blood platelet concentration of 282.8 ± 58.3 × 109/L was recorded for the baseline reading. Group A had a mean blood platelet concentration 7.9 ± 3.03 × 109/L. Group B had a mean blood platelet concentration of 4.0 ± 1.93 × 109/L. A statistically significant difference was seen between Groups A and B (p < 0.0001). Conclusions: Storage time has a significant effect of the platelet concentration of PRF. If stored over a period of 60 min, the platelet concentration of PRF increases. Further research is required to determine whether this finding is clinically significant.

Made available in DSpace on 2014-06-11T19:33:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2005-02-23Bitstream added on 2014-06-13T19:04:24Z : No. of bitstreams: 1 garcia_rv_dr_arafo.pdf: 835717 bytes, checksum: a0b9b5864c4b43379791c577605859ae (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo deste estudo foi investigar através de análise histológica a influência do plasma rico em plaquetas (PRP) na neoformação óssea dos espaços peri-implantares de implantes osseointegráveis instalados em mandíbula de cães. Foram utilizados 9 cães sem raça definida. Inicialmente foram realizados exodontias dos segundos e terceiros pré-molares, bilateralmente. Após 60 dias, as áreas foram preparadas para instalação de implantes osseointegráveis, sendo que os implantes instalados do lado direito da mandíbula não receberam tratamento com PRP, servindo como controle. Para o lado esquerdo, os implantes foram instalados em associação ao PRP, caracterizando o grupo experimental. Biópsias ósseas foram obtidas nos períodos de 15, 30, 55 dias após instalação dos implantes. Pelos resultados histológicos, de modo geral, pode-se concluir que o tratamento com PRP, conforme a metodologia empregada, não favoreceu a neoformação óssea e em alguns espécimes promoveu a formação de tecido fibroso. / This study was designed to evaluate, by means of histological analysis, the effect of platelet-rich plasma (PRP) on bone formation in the interface with osseointegrated implants placed in the dog mandible. Nine dogs of mixed race were used. Initially, the second and third inferior premolars were extracted bilaterally. After 60 days, osseointegrated implants were placed. On the right side of the mandible no treatment was done and those implants served as controls. On the left side, the implants were placed in association with PRP. Bone biopsies were taken after 15, 30 and 55 days. Results showed that PRP did not enhance bone formation and favored fibrosis in some specimens.