COMPARATIVE ULTRASTRUCTURE OF MAMMALIAN AMELOGENESIS

哺乳动物釉质形成的比较超微结构

• 批准号: 3218997
• 负责人: Ziedonis Skobe
• 金额: $ 11.92万
• 依托单位: ADA FORSYTH INSTITUTE, INC.
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-05-01 至 1988-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3218997
• 关键词: ameloblasts; colchicine; scanning electron microscopy; secretion; tetracyclines; tooth enamel

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.

我们研究的目的是确定 种间差异的结构特征的釉质，以 更好地了解如何提高健全的牙釉质形成和消除 人类的病理学 哺乳动物的釉质发生是一个统一的过程， 该过程某些组成事件的时间和空间位移 在不同的物种之间。 也就是说，观察到的物种间异质性， 釉质发生代表了一个共同主题的变化。 釉质发生分为三个主要阶段：分泌前， 分泌，成熟（或吸收），其中每一个都很容易 在所有哺乳动物的牙芽中都能辨别出来。 这些阶段仅指 釉基质蛋白，但不一定是排他性的功能， 成釉细胞或成釉器官的其他细胞在任何特定阶段。 我们 我提议检验一个假设，即在这三个阶段中的每一个阶段， 发生分泌和再吸收。 与啮齿动物相比， 牙齿形成迅速，猫的牙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，这是提出的模型 这里. 对这项研究特别重要的是， 和分泌前期成釉细胞的吸收功能， 药理学改变的分泌，以及推测的再吸收 分泌期成釉细胞的功能。 我们亦会研究 再吸收中的脉管系统和可能的分泌功能 成熟期的成釉细胞和乳头状细胞。 我们将使用适当的技术，在我们的专业知识，以确定细胞 分泌功能的釉质器官和 再吸收 超微结构细胞化学和短期放射自显影 将用于定位分泌细胞，而长期脉冲追踪 方法将定位再吸收的位点。 辣根过氧化物酶和 肌红蛋白示踪研究，结合扫描显微镜， 侧细胞膜也将指示吸收位点。 两 分泌和再吸收位点将使用秋水仙碱进一步鉴定， 四环素和氟化物来改变正常细胞的形态和功能。 我们将 检查成熟期的血管铸型，以确定血管 图案与釉质的逆流机制兼容 矿化和基质蛋白去除。