It was nearly a century ago that the viral etiology of sarcomas and leukemia (leukosis) in the domestic fowl was first described by Ellerman and Bang, working in Copenhagen, and Rous in New York. Through the following decades, in an attempt to control these oncogenic diseases which were becoming the main cause of mortality in commercial poultry, extensive investigation in many veterinary laboratories was undertaken. Throughout this period and continuing today, advancements in our understanding of the mechanisms of these viruses are ever expanding. This knowledge has exponentially expanded since the discovery and in turn the development of molecular, nucleic acid-based tools to analyze and interpret these viral genomes. This burgeoning field of research has shed light on countless topics including the elucidation of specific viral mechanisms of neoplastic induction. It has allowed for the creation of diagnostics which are vastly superior in sensitivity and specificity than to their non-molecular-based counterparts, and in the future will lead to the generation of disease resistance in the host. These topics, in specific regard to molecular studies of avian leukosis virus, will be further developed in this thesis.

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Made available in DSpace on 2015-04-14T13:29:34Z (GMT). No. of bitstreams: 1 385857.pdf: 1169830 bytes, checksum: c9ad7d18b6192a2a5654a59083bfbfc3 (MD5) Previous issue date: 2006-12-08 / Traumatismos dentoalveolares em crian?as e adolescentes s?o freq?entes e afetam diretamente os dentes, as estruturas de suporte e os tecidos moles adjacentes, contribuindo para o aparecimento de problemas psicossociais e econ?micos importantes. A avuls?o dent?ria ? considerada a les?o dentoalveolar que maior dano provoca no paciente e constitui-se em uma urg?ncia odontol?gica. O progn?stico de dentes avulsionados depende de forma significativa de condutas r?pidas e eficientes ainda no local do acidente, exigindo, portanto, que pais ou respons?veis tenham conhecimentos sobre maneiras de atuar frente a tais les?es. O objetivo desta pesquisa ? avaliar o n?vel de conhecimento de pais ou respons?veis sobre as condutas adotadas frente ?s avuls?es dent?rias e associar esse n?vel de conhecimento ?s vari?veis grau de escolaridade, faixa de renda familiar mensal e idade. Neste estudo, um total de 107 pais ou respons?veis foram entrevistados por meio de um question?rio composto de 12 perguntas objetivas, diretas e com respostas graduadas entre 0 e 3 pontos. Os resultados demonstraram que, apesar de 90% dos entrevistados responderem que procurariam de imediato, um servi?o profissional, 71% desconheciam o que era avuls?o, apenas 3% utilizariam o leite como meio de conserva??o e 5% promoveriam o reimplante do dente avulsionado. As m?dias finais seguiram uma distribui??o de 44,63% para o grau 3, 15,88% para o grau 2, 17,99% para o grau 1 e 21,47% para o grau 0. Concluiu-se que o n?vel de conhecimento dos pais ou respons?veis sobre avuls?o dent?ria ? baixo e que as vari?veis n?o tiveram associa??o significativa com a pontua??o obtida ao longo do question?rio.

Les m?canismes de l?emphys?me pulmonaire, caract?ris? par la destruction des alv?oles pulmonaire, sont incompl?tement connus. L?hypoth?se d?fendue par cette th?se est qu?une alt?ration des syst?mes d?alv?olog?n?se et de r?paration alv?olaire port?s par les fibroblastes pulmonaires contribue au d?veloppement des l?sions au cours de cette maladie. Les travaux pr?sent?s ici ont permis d??tablir que les fibroblastes pulmonaires cultiv?s in vitro ? partir de poumon emphys?mateux pr?sentaient un ph?notype alt?r? dans le sens d?une perte de leur capacit? ? participer ? la r?g?n?ration et ? la r?paration des alv?oles : Ces cellules s?cr?taient ? un niveau faible ou non stimulable le Hepatocyte Growth Factor et le Keratinocyte Growth Factor (KGF), qui ciblent les cellules ?pith?liales et endoth?liales de l?alv?ole. De plus, l?expression par ces cellules de l??lastine, le composant majeur de la matrice extracellulaire pulmonaire, n??tait pas induite par l?acide tout-trans r?tino?que, stimulus central de l?alv?olog?n?se, du fait d?une faible expression de Cellular Retinoic Acid Binding Protein 2 (CRABP2). Le r?le du KGF dans l?hom?ostasie de l?alv?ole a ?t? d?montr? dans le mod?le d?emphys?me induit par l??lastase in vivo : Les souris trait?es par le KGF avant l?instillation d??lastase ?taient prot?g?es de l?emphys?me. Les souris dont le g?ne de CRABP2 ?tait inactiv? de fa?on globale n??taient pas sensibilis?es vis-?-vis de l?emphys?me dans ce mod?le. Les donn?es physiopathologiques pr?sent?es dans ce m?moire pourraient contribuer ? l?identification de nouvelles cibles th?rapeutiques pour l?emphys?me. / The mechanisms of pulmonary emphysema, characterized by the destruction of alveolar walls, remain incompletely understood. Our hypothesis is that a deficiency in fibroblast-borne alveolar repair systems accounts partly for the constitution of lesions in this disease. In our experiments, we show that fibroblasts isolated in vitro from human emphysematous lung express the Hepatocyte Growth Factor and the Keratinocyte Growth Factor (KGF), which target alveolar epithelial and endothelial cells, at low or unstimulable levels. Additionally, emphysema fibroblasts did not increase their expression of elastin, the main component of the pulmonary extracellular matrix, in response to retinoic acid, due to a low expression of Cellular Retinoic Acid Binding Protein 2 (CRABP2). The role of KGF In alveolar homeostasis was demonstrated in vivo in the elastase-induced emphysema model: Mice treated with KGF before elastase instillation were protected against emphysema. CRABP2- knockout mice were not protected against emphysema in this model. Our pathophysiological data may help in the identification of novel therapeutic targets for emphysema.

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