A morphological and functional investigation of the enamel organ and enamel was carried out on the incisor of the rat. Using transmission electron microscopy and other electron optical techniques, the ultrastructure of enamel hydroxyapatite crystallites and the morphology of the cells of the enamel organ related to these crystallites were examined. In the enamel secretion zone, putative cell communication via matched approaches of rough endoplasmic reticulum to the ameloblast cell membrane was not confirmed. Throughout the enamel organ, extracellular permeability was assessed using radiolabeled proteins as tracers. Regional differences were found, especially related to the two types of maturation ameloblasts. Several modified histochemical techniques were successfully applied to the enamel such that the functional contribution of each type of ameloblast was ascertained. In this way it was demonstrated that several functional cell subpopulations exist and that they can be correlated with different calcium and protein distributions within the enamel. In vivo injection of vinblastine, and in vitro treatments with other drugs, all severely modified the enamel maturation staining pattern and $ sp{45}$Ca uptake. In addition, it was found that ruffle-ended maturation zone ameloblasts possess higher levels of specific transferrin receptor sites relative to smooth-ended ameloblasts, a finding that may be directly related to the deposition of iron within the enamel.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75424 |
| Date | January 1987 |
| Creators | McKee, Marc Douglas. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Anatomy.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000550580, proquestno: AAINL44267, Theses scanned by UMI/ProQuest. |
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