RESUMO
The chicken eggshell is a composite bioceramic containing organic and inorganic phases. The organic phase contains, among other constituents, type X collagen and proteoglycans (mammillan, a keratan sulfate proteoglycan, and ovoglycan, a dermatan sulfate proteoglycan), whose localization depends on a topographically defined and temporally regulated deposition. Although the distribution of these macromolecules in the eggshell has been well established, little is known about their precise localization within eggshell substructures and oviduct cells or their pattern of production and function during eggshell formation. By using immunofluorescent and immuno-ultrastructural analyses, we examined the distribution of these macromolecules in oviduct cells at different post-oviposition times. To understand the role of proteoglycan sulfation on eggshell formation, we studied the effects of inhibition of proteoglycan sulfation by treatment with sodium chlorate. We showed that these macromolecules are produced by particular oviduct cell populations and at precise post-oviposition times. Based on the precise ultrastructural localization of these macromolecules in eggshell substructures, the timing of the secretion of these macromolecules by oviduct cells and the effects on eggshell formation caused by the inhibition of proteoglycan sulfation, the putative role of mammillan is in the nucleation of the first calcite crystals, while that of ovoglycan is to regulate the growth and orientation of the later forming crystals of the chicken eggshell.
Assuntos
Casca de Ovo/metabolismo , Matriz Extracelular/metabolismo , Animais , Galinhas , Cloratos/metabolismo , Casca de Ovo/fisiologia , Casca de Ovo/ultraestrutura , Feminino , Substâncias Macromoleculares , Oviductos/metabolismo , Oviductos/ultraestrutura , Coloração e Rotulagem/métodosRESUMO
Pulmonary thromboendarterectomy under circulatory arrest and deep hypothermia is presently a curative treatment for pulmonary hypertension secondary to chronic pulmonary artery thromboembolic occlusion, but is still not frequently performed around the world. We report here the first successful pulmonary thromboendarterectomy under circulatory arrest performed in Chile. The patient was a 37 year old white man, high school teacher, with a 5 months history of effort dyspnea and cough. Pulmonary hypertension secondary to chronic pulmonary thromboembolism was confirmed by angiography and echocardiography. The patient was operated on April 27, 1995. After the operation the patient had an immediate and maintained normalization of his pulmonary hemodynamics. He presented periods of delirium that postponed mechanical ventilation disconnection until the 7th postoperative day, after which he had an uneventful neurological recovery. Before hospital discharge a control angiography showed complete patency of the pulmonary artery system with no evidence of residual thrombi. Presently he is enjoying a normal life and back to his teaching activities.