Developmental aspects of secondary palate formation.
Developmental aspects of secondary palate formation.
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发表时间：
1976-10
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通讯作者：
R. Greene;R. Pratt
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作者：
R. Greene;R. Pratt
在过去，对次级腭发育的研究主要涉及陆架隆起和融合的形态学方面。许多因素被认为是参与腭部抬高，如胎儿神经肌肉活动和颅底和下颌骨的生长，以及生产的细胞外基质和收缩元素的腭，主要是基于肉眼，光镜，形态测量或组织化学观察。最近，更多的生化程序已被用来描述腭架隆起。虽然这些研究强烈表明，腭细胞外基质在货架运动中起着重要作用，这些数据的解释仍然很困难，由于颅面发育中所涉及的组织相互作用的复杂性。货架升降似乎并不涉及一个单一的动力因素，而是一个协调的相互作用的所有上述发展事件。进一步分析货架升降的机制，需要开发新的，并完善现有的体外程序。一个系统，使人们能够检查货架海拔在体外将允许更有意义的分析的相对重要性的各种组件在货架运动。关于腭架的融合，人们知道得更多，这在很大程度上是由于体外研究。无论在体内还是体外，并置支架的融合都依赖于中线上皮细胞的粘附和细胞死亡。上皮细胞表面大分子参与了上皮细胞表面的粘附。对腭上皮粘附的进一步分析应针对负责这种粘附相互作用的细胞表面成分的表征。中线上皮细胞在搁板升高和接触前24-36 h停止DNA合成，在细胞表面糖蛋白的合成中变得活跃，随后表现出坏死的形态学迹象。中线上皮细胞的死亡被认为涉及程序性的、溶酶体介导的自溶。
Research on development of the secondary palate has, in the past, dealt primarily with morphological aspects of shelf elevation and fusion. The many factors thought to be involved in palatal elevation, such as fetal neuromuscular activity and growth of the cranial base and mandible, as well as production of extracellular matrix and contractile elements in the palate, are mostly based on gross, light microscopic, morphometric or histochemical observations. Recently, more biochemical procedures have been utilized to described palatal shelf elevation. Although these studies strongly suggest that palatal extracellular matrix plays a major role in shelf movement, interpretation of these data remains difficult owing to the complexity of tissue interactions involved in craniofacial development. Shelf elevation does not appear to involve a single motive factor, but rather a coordinated interaction of all of the abovementioned developmental events. Further analysis of mechanisms of shelf elevation requires development of new, and refinement of existing, in vitro procedures. A system that enables one to examine shelf elevation in vitro would allow more meaningful analysis of the relative importance of the various components in shelf movement. Much more is known about fusion of the palatal shelves, owing in large part to in vitro studies. Fusion of the apposing shelves, both in vivo and in vitro, is dependent upon adhesion and cell dealth of the midline epithelial cells. Adhesion betweeen apposing epithelial surfaces appears to involve epithelial cell surface macromolecules. Further analysis of palatal epithelial adhesion should be directed towards characterization of those cell surface components responsible for this adhesive interaction. Midline epithelial cells cease DNA synthesis 24-36 h before shelf elevation and contact, become active in the synthesis of cell surface glycoproteins, and subsequently manifest morphological signs of necrosis. Death of the midline epithelial cells is thought to involve a programmed, lysosomal-mediated autolysis...