RESUMO
Signalling cascades first described in Drosophila have been found to regulate patterning and outgrowth in a number of structures in higher vertebrates. We sought to determine whether the evolutionarily conserved genes were important during the development of the tongue. In situ hybridisation was used to determine the temporo-spatial expression of a panel of conserved genes. Histological examination and incorporation of BrdU were used to determine the mechanism by which the tongue develops. We show that evolutionarily conserved genes were expressed in distinct dynamic patterns during tongue development. Sonic Hedgehog (Shh) and Patched (Ptc) were found only in the dorsal tongue epithelium. Shh expression was only observed in the suprabasal layers, whereas Ptc was observed in both basal and suprabasal layers. Cell division in the epithelium was concentrated in regions devoid of Shh. Expression of bone morphogenetic protein-7 (BMP) was identical to that of Shh. Shh and Ptc expression were never detected in the mesenchyme. Ectopic expression of Noggin (a potent antagonist of the BMPs) caused severe abnormalities in tongue morphology, including swelling of the mesenchymal component and a thickening of the epithelial layer. Data from this study suggests that the epithelium and mesenchyme express quite different genes during development. However BMP activity acts to inhibit growth in both tissues.
Assuntos
Língua/embriologia , Fator de Crescimento Transformador beta , Ativinas/genética , Animais , Proteína Morfogenética Óssea 7 , Proteínas Morfogenéticas Ósseas/genética , Proteínas Morfogenéticas Ósseas/fisiologia , Proteínas de Transporte , Divisão Celular , Embrião de Galinha , Epitélio/química , Epitélio/metabolismo , Proteínas Fetais/genética , Folistatina , Expressão Gênica , Proteínas Hedgehog , Proteínas de Membrana/genética , Mesoderma/química , Mesoderma/metabolismo , Receptores Patched , Proteínas/genética , RNA Mensageiro/análise , Receptores Proteína Tirosina Quinases/genética , Receptor EphA4 , Receptores de Superfície Celular , Língua/química , Língua/citologia , Transativadores/genéticaRESUMO
The interaction of blood with new artificial surfaces is an area of continual medical interest. In this study, a series of polyether/polysiloxane networks were synthesized, characterized in terms of both bulk and surface compositions, and evaluated for blood compatibility. The crosslinked networks were produced by reacting the epoxy groups of polyglycidoxy propyl methyl siloxane (PGPMS) with the hydroxyl end groups of polypropylene glycol (PPG). Blood compatibility was evaluated using an in vitro platelet retention test and fibrinogen adsorption experiments from human plasma and buffered saline. The PPG/PGPMS networks exhibit low fibrinogen adsorption and low platelet activation. Such properties make the networks potentially attractive as materials for blood-interfacing applications.
Assuntos
Materiais Biocompatíveis , Sangue , Polímeros , Propilenoglicóis , Silicones , Siloxanas , Adsorção , Plaquetas/fisiologia , Fibrinogênio , Humanos , Técnicas In Vitro , Propriedades de SuperfícieRESUMO
Percutaneous transluminal angioplasty was performed successfully in three patients with total occlusions involving the iliac artery. Two patients had occlusion of the external iliac artery and the third patient had occlusion of the common iliac artery. The vessels were still patent at 3-12 months after the procedure. One complication occurred involving a thrombus in the common femoral artery of the diseased leg. The thrombus was surgically removed under local anesthesia. In high-risk patients, percutaneous transluminal angioplasty of total iliac artery occlusions may represent a viable alternative to surgery.
