RESUMEN
Type X collagen is a transient and developmentally regulated collagen that has been postulated to be involved in controlling the later stages of endochondral bone formation. However, the role of this collagen in these events is not yet known. In order to understand the function of type X collagen, if any, in the process of biomineralization, the properties of type X collagen in eggshell membranes were further investigated. Specifically, calvaria-derived osteogenic cells were tested for their ability to mineralize eggshell membranes in vitro. Immunohistochemistry with specific monoclonal antibodies was used to correlate the presence or absence of type X collagen or its propeptide domains with the ability of shell membranes to be mineralized. The extent of mineralization was assessed by Von Kossa staining, scanning electron microscopy and energy-dispersive spectroscopy. The results indicate that the non-helical domains of type X collagen must be removed to facilitate the cell-mediated mineralization of eggshell membranes. In this tissue, intact type X collagen does not appear to stimulate or support cell-mediated mineralization. We postulate that the non-helical domains of type X collagen function in vivo to inhibit mineralization and thereby establish boundaries which are protected from mineral deposition.
Asunto(s)
Colágeno/fisiología , Cáscara de Huevo/metabolismo , Minerales/metabolismo , Secuencia de Aminoácidos , Animales , Membrana Celular/química , Membrana Celular/metabolismo , Embrión de Pollo , Colágeno/análisis , Colágeno/química , Inmunohistoquímica , Microscopía Electrónica de Rastreo , Minerales/análisis , Datos de Secuencia Molecular , Pepsina A/farmacologíaRESUMEN
Failure to procure organs, tissues, and corneas for transplantation can be attributed to a number of factors. The existing literature is largely speculative concerning why health care professionals (HCPs) fail to approach the families of medically suitable donors and why requests for donation are not successful. This study is based on the direct examination of 1,797 HCP attitudes and knowledge about donation in conjunction with how HCPs performed when faced with a donor-eligible patient. HCP attitudes, rather than knowledge, are more important to the successful procurement of organs. The HCPs with more positive attitudes about donation and their role in the procurement process were more likely to request donation. HCPs were more successful in obtaining consent to donation when they believed that the donation process would benefit the donor family and that their efforts to procure organs would be successful. These results indicate that educating HCPs about the donation process to make them more comfortable with it is crucial.