RESUMO
A 25-kDa homodimeric protein was purified from demineralized bovine bone extract and identified as activin A. The bovine bone activin enhanced formation of ectopic bone in rat subcutis when implanted in combination with partially purified bovine bone morphogenetic protein (BMP-2, BMP-3) in collagen/ceramic carrier. The implants, removed at 14 days, contained markedly elevated levels of alkaline phosphatase activity. Histological examination revealed an extensive formation of woven bone with very little cartilage. In contrast, a combination of transforming growth factor-beta 2 and BMP promoted formation of bone with an abundance of cartilage. The implants with BMP alone exhibited some osteoinductive activity, while the implants with activin alone showed no activity. These results demonstrate that bone is a rich source of activin and that activin plays an important role in modulating bone formation.
Assuntos
Desenvolvimento Ósseo/efeitos dos fármacos , Osso e Ossos/fisiologia , Substâncias de Crescimento/farmacologia , Hematopoese/efeitos dos fármacos , Inibinas/farmacologia , Hipófise/metabolismo , Proteínas/farmacologia , Ativinas , Sequência de Aminoácidos , Animais , Proteínas Morfogenéticas Ósseas , Osso e Ossos/efeitos dos fármacos , Bovinos , Células Cultivadas , Cromatografia em Gel , Brometo de Cianogênio , Hormônio Foliculoestimulante/metabolismo , Técnicas In Vitro , Inibinas/isolamento & purificação , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Fragmentos de Peptídeos/isolamento & purificação , Hipófise/efeitos dos fármacos , Proteínas/isolamento & purificação , Ratos , Ratos Endogâmicos , Fator de Crescimento Transformador beta/isolamento & purificação , Fator de Crescimento Transformador beta/farmacologiaRESUMO
Acute myelofibrosis is a rare clinical entity characterized by severe marrow fibrosis and peripheral blood pancytopenia. It may be very closely related to and has been considered synonymous with megakaryocytic leukemia. Chloroma is also a rare entity composed of a localized collection of immature myeloid cells and is associated with a known or covert leukemia. A patient presenting with a rare combination of acute myelofibrosis, megakaryocytic leukemia and multiple chloromas of the mandible and skin, are described. Although presenting a diagnostic challenge, their combination in one patient aids in the understanding of the myeloproliferative process. To our knowledge, this is the 3rd case of chloroma involving the oral osseous structures.
