RESUMO
Background: The platelet-derived growth factor (PDGF) is expressed in a wide variety of cell types, exerts a potent mitogenic role and acts on the growth, differentiation and cell chemotaxis. Studies have shown that during folliculogenesis, PDGF and their receptors are expressed in oocytes, granulosa cells and thecal cells of ovarian follicles at different developmental stages in several species. Although exist many information about its expression sites, as well as about its action in different cells types, the role of PDGF on ovarian folliculogenesis remains understudied. Thus, this article aims to review issues related to PDGF, suggesting the involvement of this mitogenic factor during follicular development. Review: Along this work, it was shown aspects related to structural characterization of PDGF and its receptors, as well as PDGF expression in different cells types, emphasizing its importance to follicular development. PDGF family is composed by four polypeptide chains (each encoded by a different gene), which are synthesized in the form of inactive pro-proteins. After a proteolytic processing, these chains undergo homo or heterodimerization, resulting in five isoforms (PDGF-AA, -BB, -AB, -CC e -DD). The cellular effects of these different PDGF isoforms are mediated by binding, with different specificities, to three transmembrane receptors isoforms of type tyrosine kinase generated by the association of subunits alpha e beta (PDGFR- alphaalpha, - alphabeta, - betabeta)...(AU)
Assuntos
Fator de Crescimento Derivado de Plaquetas/química , Estrutura Molecular , Ovário , Fator de Crescimento Derivado de Plaquetas/genéticaRESUMO
Background: The platelet-derived growth factor (PDGF) is expressed in a wide variety of cell types, exerts a potent mitogenic role and acts on the growth, differentiation and cell chemotaxis. Studies have shown that during folliculogenesis, PDGF and their receptors are expressed in oocytes, granulosa cells and thecal cells of ovarian follicles at different developmental stages in several species. Although exist many information about its expression sites, as well as about its action in different cells types, the role of PDGF on ovarian folliculogenesis remains understudied. Thus, this article aims to review issues related to PDGF, suggesting the involvement of this mitogenic factor during follicular development. Review: Along this work, it was shown aspects related to structural characterization of PDGF and its receptors, as well as PDGF expression in different cells types, emphasizing its importance to follicular development. PDGF family is composed by four polypeptide chains (each encoded by a different gene), which are synthesized in the form of inactive pro-proteins. After a proteolytic processing, these chains undergo homo or heterodimerization, resulting in five isoforms (PDGF-AA, -BB, -AB, -CC e -DD). The cellular effects of these different PDGF isoforms are mediated by binding, with different specificities, to three transmembrane receptors isoforms of type tyrosine kinase generated by the association of subunits alpha e beta (PDGFR- alphaalpha, - alphabeta, - betabeta)...
Assuntos
Estrutura Molecular , Fator de Crescimento Derivado de Plaquetas/química , Fator de Crescimento Derivado de Plaquetas/genética , OvárioRESUMO
Por medio de esta revisión bibliográfica se pretende mostrar lo que existe en la actualidad sobre la biocompatibilidad, las características del titanio y su uso para implantes dentales y los eventos celulares y moleculares que se desencadenan con la colocación de un implante intraóseo en los maxilares. Se discute la terminología de: biotolerante, bioinerte, bioactivo, biointegración, bioaceptabilidad. Se establecen las características que hacen del titanio el material de eleción para su uso en los implantes dentales y los factores que permiten que se logre con ellos la oseointegración. En cuanto a los fenómenos celulares, se destaca el papel del osteoblasto como el blanco perfecto que permite desencadenar el proceso biológico que lleva a la oseointegración. A la vez se discute a nivel molecular todo el proceso de fenomenologías que ocurre desde el momento de la colocación del implante para permitir por parte del organismo una cicatrización normal alrededor de un cuerpo extraño. Esta información nos lleva a pensar que el entendimiento y manejo de todos estos eventos celulares y moleculares serían de gran utilidad para mejorar el éxito de los implantes dentales y extender su uso a sitios anatómicos que presentan dificultad a la terapéutica actual