COMPARATIVE ULTRASTRUCTURE OF MAMMALIAN AMELOGENESIS

我们研究的目标是确定其功能意义。 种间釉质发生的结构特征差异 更好地了解如何促进健全的牙釉质形成和消除 人类的病理学。哺乳动物的成釉是一个统一的过程 该过程某些组成部分事件的时间和空间位移 在不同的物种中。也就是说，观察到的物种间异质性 成釉作用代表了一个共同主题的变种。 成釉过程分为三个主要阶段：成釉前， 分泌性和成熟性(或再吸收)，每一种都很容易 在所有哺乳动物的牙蕾中都能辨别出来。这些阶段仅指 釉质基质蛋白，但不一定具有独有的功能 成釉细胞或成釉器官中任何特定阶段的其他细胞。我们 建议检验假设，在三个阶段中的每一个阶段 分泌和吸收就会发生。与啮齿动物不同的是， 牙齿形成很快，猫的釉质发生中的特定事件非常 在时间和空间上有明确的定义。因此，这就是所提出的模型 这里。对这项研究特别重要的是假定的分泌物 和成釉细胞在记忆前期的吸收功能， 药物改变的分泌物和推测的吸收 分泌期成釉细胞的功能。我们还将研究 骨吸收中的血管系统及其可能的分泌功能 成釉细胞和乳头细胞处于成熟期。 我们将使用适当的技术，在我们的专业知识范围内，识别细胞 釉质器官在分泌中起作用，而那些在 再吸收。超微结构细胞化学与短期放射自显影 将用于定位分泌细胞，而较长期的脉冲追逐 这些方法将对吸收部位进行定位。辣根过氧化物酶和 肌红蛋白示踪研究，结合扫描显微镜 侧方细胞膜，也将指示吸收部位。两者都有 将使用秋水仙素进一步确定分泌和吸收部位， 四环素和氟化物可以改变正常的细胞形态和功能。我们会 检查成熟期的血管铸型以确定血管是否 图案与搪瓷的逆流机构兼容 矿化和基质蛋白去除。

The goal of our research is to determine the functional significance of interspecies differences in structural features of amelogenesis in order to better understand how to enhance sound enamel formation and eliminate pathology in humans. Mammalian amelogenesis is a unified process with temporal and spatial displacement of some component events of that process among various species. That is, interspecies heterogeneity observed in amelogenesis represents variations on a common theme. Amelogenesis has been segmented into three major stages; presecretory, secretory, and maturation (or resorptive), each of which is readily discernible in all mammalian tooth buds. These stages refer solely to enamel matrix proteins, but not necessarily to exclusive functions of ameloblasts or other cells of the enamel organ at any specific stage. We propose to test the hypothesis that within each of the three stages secretion and resorption occurs. In contrast to rodents, animals whose teeth form rapidly, specific events in amelogenesis of cats are very clearly defined in time and space. Consequently this is the model proposed here. Of particular importance to this study are the putative secretory and resorptive functions of ameloblasts in the presecretory stage, pharmacologically altered secretion, and the speculated resorptive functions of secretory stage ameloblasts. We will also study the role of the vasculature in resorption and the possible secretory function of ameloblasts and papillary cells in the maturation stage. We will use appropriate techniques, within our expertise, to identify cells of the enamel organ functioning in secretion and those functioning in resorption. Ultrastructural cytochemistry and short term autoradiography will be used to localize secretory cells, whereas longer term pulse chase methods will localize sites of resorption. Horseradish peroxidase and myoglobin tracer studies, in conjunction with scanning microscopy of lateral cell membranes, will also indicate sites of resorption. Both secretion and resorption sites will be further identified using colchicine, tetracycline, and fluoride to alter normal cell form and function. We will examine vascular casts of the maturation stage to determine if the vascular pattern is compatible with a counter-current mechanism for enamel mineralization and matrix protein removal.