Ultrastructural studies and immunolocalization of enamel proteins in rodent secretory stage ameloblasts processed by various cryofixation methods

Nanci, Antonio; Kawaguchi, H.; Kogaya, Yasutoku

doi:10.1002/ar.1092380402

Cited by 22 publications

(12 citation statements)

References 40 publications

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“…Proteins which play a role in the nucleation of calcium phosphates in enamel and dentine include amelogenin and collagen I, respectively. Collagen I, from dentine, was observed to penetrate across the DEJ into enamel (Lin et al, 1993) and amelogenins were also found in the mantle dentine (Nanci et al, 1994). As the specimens in the present investigation were prepared from mature permanent teeth, it would be logical to infer that the crystals observed at the DEJ are reflective of both enamel and dentine since the relevant proteins from both tissues are present at the DEJ during the developmental stage.…”

Section: Microstructural Features At the Dejmentioning

confidence: 79%

Nano-scale structure and mechanical properties of the human dentine–enamel junction

Chan

Ngan

King

2011

Journal of the Mechanical Behavior of Biomedical Materials

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Section: Microstructural Features At the Dejmentioning

confidence: 79%

Nano-scale structure and mechanical properties of the human dentine–enamel junction

Chan

Ngan

King

2011

Journal of the Mechanical Behavior of Biomedical Materials

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“…Such preorganization can result from different mechanisms. It is well documented that amelogenins are secreted by ameloblasts and are present during DEJ mineralization in both tissues (Nanci et al 1994). The mineralization of the outer dentin layer could induce an immobilization of amelogenins.…”

Section: Discussionmentioning

confidence: 99%

“…These two characteristics were also considered as their only common property for a long time. Recent cellular biology data on the extracellular matrix (ECM) components and their expression in odontoblast and ameloblast cells showed complex relationships between both tissues (Nanci et al 1994). The development of individual enamel and dentin crystals appeared, however, to be roughly comparable and was described in a four-step process (Houllé et al 1997).…”

Section: Introductionmentioning

confidence: 99%

High-resolution electron-microscopic study of the relationship between human enamel and dentin crystals at the dentinoenamel junction

Bodier-Houllé

Steuer

Meyer

et al. 2000

Cell and Tissue Research

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The development of dentin and of enamel share a common starting locus: the dentinoenamel junction (DEJ). In this study the relationship between enamel and dentin crystals has been investigated in order to highlight the guiding or modulating role of the previously mineralized dentin layer during enamel formation. Observations were made with a high-resolution electron microscope and, after digitalization, image-analysis software was used to obtain digital diffractograms of individual crystals. In general no direct epitaxial growth of enamel crystals onto dentin crystals could be demonstrated. The absence of direct contact between the two kinds of crystals and the presence of amorphous areas within enamel particles at the junction with dentin crystals were always noted. Only in a few cases was the relationship between enamel and dentin crystals observed, which suggested a preorganization of the enamel matrix influenced by the dentin surface structure. This could be explained either by the existence of a proteinaceous continuum between enamel and dentin or by the orientation of enamel proteins by dentin crystals.

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“…Samples fixed with 1% glutaraldehyde or with the aldehyde mixture were post-fixed with potassiumferrocyanide-reduced osmium tetroxide (Neiss, 1984), dehydrated in acetone, and routinely processed for embedding in Epon. Some segments of glutaraldehyde-fixed material were cryoprotected with 30% glycerol and dehydrated by freeze-substitution in 1% osmium tetroxide in pure acetone, as previously described (Nanci et al, 1994). Ultrathin sections of tissues were stained with uranyl acetate and lead citrate and examined with a Philips 400 or a JEOL JEM 2000FX-II electron microscope operated at 80 kV.…”

Section: Morphological Characterization Of Enamel Growth Sitesmentioning

confidence: 99%

Transient Accumulation of Proteins At Interrod and Rod Enamel Growth Sites

et al. 1996

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Conceptually, there should be a brief interval in time when newly secreted proteins "pile up" at secretory sites just outside the membrane of ameloblasts. Indeed, previous cytochemical studies have suggested that glycosylated and/or sulfated glycoproteins accumulate at enamel growth sites. Colloidal gold lectin cytochemistry and immunocytochemistry with antibodies to enamel proteins and phosphoserine, combined with cycloheximide and brefeldin A to inhibit protein synthesis and secretion, were applied to characterize the distribution of newly formed proteins at enamel interrod and rod growth sites. Although enamel growth sites show a "rarefied" appearance, the results indicate that one or more subclasses of enamel proteins accumulate near the cell surface at sites where elongation of enamel crystallites contributes to thickening of the enamel layer. These proteins are glycosylated and/or phosphorylated and, at least in the case of the glycosylated ones, are rapidly processed after they are released extracellularly. In contrast, immunolabeling for amelogenins is generally weaker near the cell surface and more intense at a short distance away from the site where crystallites elongate. The data suggest that the enamel proteins accumulating at growth sites likely belong to the non-amelogenin category and play a transient role in promoting the lengthening of crystallites. It is concluded that areas near the ameloblast membrane where certain enamel proteins accumulate in fact constitute the equivalent of a mineralization front.

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Ultrastructural studies and immunolocalization of enamel proteins in rodent secretory stage ameloblasts processed by various cryofixation methods

Cited by 22 publications

References 40 publications

Nano-scale structure and mechanical properties of the human dentine–enamel junction

Nano-scale structure and mechanical properties of the human dentine–enamel junction

High-resolution electron-microscopic study of the relationship between human enamel and dentin crystals at the dentinoenamel junction

Transient Accumulation of Proteins At Interrod and Rod Enamel Growth Sites

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