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Topic: Ameloblasts

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	Ameloblastoma (Site not responding. Last check: 2007-11-06)
		Willis (1948) guarantees that the term "ameloblastoma" as well as its predecessor "adamantinoma" are misnomers, as the tumor does not develop from the ameloblasts, nor does it form enamel, and assures that "it would be better to call them carcinomas of the tooth-germ residues", reaffirming his opinion of the malignancy of the neoplasm.
		Ameloblastic differentiation: Once the odontoblastic layer is complete, the formation of the dentin matrix begins with a thickening of the basal membrane which separates the two tissues.
		With the formation of the dentin matrix there is an interruption of the source of nourishment for the cells of the inner epithelium of the enamel organ which obliges these cells to acquire their nutrients at another source, I.e., from the stellate reticulum.
	www.forp.usp.br /bdj/t0111.html (3140 words)

	Enamel Developement
		Ameloblasts are organized into a layer of highly prismatic cells that secrete enamel proteins such as amelogenin.
		The process by which enamel proteins such as amelogenin mediate the formation of hydroxyapatite crystals from calcium and phosphate is called enamel biomineralization.
		This figure illustrates the localization of the amelogenin protein in the ameloblast cells and their secretory vesicles as well as in the newly formed enamel layer of developing teeth.
	dentistry.uic.edu /CraniofacialGenetics/ResearchTED.htm (1297 words)

	Tooth enamel - Wikipedia, the free encyclopedia
		Both ameloblasts (the cells which initiate enamel formation) and Tomes' processes affect the crystals' pattern.
		In the secretory stage, ameloblasts are polarized columnar cells.
		When this first layer is formed, the ameloblasts move away from the dentin, allowing for the development of Tomesâ processes at the apical pole of the cell.
	en.wikipedia.org /wiki/Tooth_enamel (3698 words)

	[No title]
		In mammalian enamel formation, the closely apposed columnar ameloblasts are arranged hexagonally, in a “closest packing pattern”.
		The ideal hexagon in the lower left corner represents the cross sectional area of one ameloblast producing a prism and interprismatic enamel along its peripheral rim.
		Areas of hexagon and tetragon are equal, both expressing the size of the secretory area of one ameloblast.
	www.toyen.uio.no /palmus/forskning/g_fosse.html (1125 words)

	Brazilian Dental Journal - Are there structural alterations in the enamel organ of offspring of rats with ... *(Site not responding. Last check: 2007-11-06)*
		In the rats born to treated and untreated diabetic mothers, there was thinning of the enamel matrix and of the ameloblasts and the nuclear area of the latter was smaller.
		The following parameters were evaluated: thickness of the enamel matrix, ameloblast height, area of the ameloblast nucleus, ratio of the largest and smallest diameters of the ameloblast nucleus, thickening of the intermediate layer, thickness of the stellate reticulum, and area corresponding to the interstitium of the stellate reticulum.
		Considering that increased permeability of the basement membrane of different tissues occurs in diabetic patients, we may assume that the increase in the area corresponding to the interstitium of the stellate reticulum is due to an increase in fluid promoted by the greater permeability of blood vessels present in the region.
	www.scielo.br /scielo.php?script=sci_arttext&pid=S0103-64402003000300004 (2739 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		The ameloblasts are attached to each other via desmosomes at both the proximal and distal ends.
		Tomes' processes develop at the apical end of the ameloblasts during the secretory stage Terminal bar apparatus- junctional complexus appear at the junction of the cell bodies and Tomes's processes The enamel matrix is formed in rods that are continuous from the DEJ to the surface of the tooth.
		Following the final stage of mineralization, the shorten ameloblasts secrete the developmental or primary cuticle development of the tooth root Root sheath cervical loop- where the IEE and OEE come together When the crown is complete the cells continue to length forming a double layer of cells-epithelial root sheath (Hertwig's sheath).
	www.dds2001.com /mnemonic/2HIST6.txt (442 words)

	Localization of Transcriptional Co-activator CBP in the Ameloblasts and the Other Enamel Organ-derived Cells of the Rat ...
		Ameloblasts in the late maturation zone from two neighboring sections of the same incisor were labeled with the antibodies against CBP(C-1) ( a,b) and c-Jun ( c,d).
		Ameloblasts in the secretion zone ( a), in the transition zone ( b), in the early maturation zone just after the transition ( c), in the second RA region of the maturation zone ( d), and in the second SA region of the maturation zone ( e).
		Josephsen K, Fejerskov O (1977) Ameloblast modulation in the maturation zone of the rat incisor enamel organ.
	www.jhc.org /cgi/content/full/50/11/1455 (2694 words)

	Development -- Gritli-Linde et al. 129 (23): 5323 Figure IG2
		At this time, ZO-1 is absent from the apical and basal aspect of Smo mutant ameloblasts (a) in molars (arrowhead in D) and incisors (F), whereas it accumulates in the ode (arrow in D), which remains as a continuous layer (B,D).
		Note that by this stage mutant ameloblasts are severely shrunken, and the strong staining visible is associated with cells of the stratum intermedium and ode (H).
		In mutant incisors, E-cadherin is barely detectable in ameloblasts, and the papillary layer (arrow in P) is unrecognizable.
	dev.biologists.org /cgi/content-nw/full/129/23/5323/FIG2 (416 words)

	[No title]
		Although ameloblasts differentiate terminally and start the deposition of enamel matrix only after the completion of crown morphogenesis, there is increasing evidence suggesting that the segregation of the ameloblast cell lineage may start much earlier.
		Secretory ameloblasts contain lysosomal enzymes in the Golgi lysosome endoplasmic reticulum system and also exhibit absorptive capacity, which might be associated with an early decrease in extracellularly degraded enamel proteins.
		These results suggest that the secretory ameloblast is a highly specialized multifunctional cell in the production, resorption and degradation of enamel matrix and in the active calcium transport essential for matrix mineralization during enamel formation.
	www.novartisfound.org.uk /catalog/205abs.htm (3608 words)

	Effects of Fluoride on the Cytoskeleton of Ameloblasts (Site not responding. Last check: 2007-11-06)
		OBJECTIVE: The goal of this project was to develop a model system for demonstration of the effects of fluoride on the cytoskeleton of ameloblasts in developing teeth.
		Preliminary quantitation indicated that phalloidin intensity was greater in ameloblasts of NaF-treated compared to NaCl-treated tooth germs, using both fluorescent and confocal microscopy.
		Treatment with Y-27632, an inhibitor of ROCK kinase, led to rounded ameloblasts and abrogation of phalloidin stain, due to reduction in F-actin.
	iadr.confex.com /iadr/2004Hawaii/techprogram/abstract_41694.htm (346 words)

	Figure - Nature Genetics (Site not responding. Last check: 2007-11-06)
		In the apposition phase, one of the final stages of odontogenesis and the development gone awry in DGI, enamel and dentin are secreted in successive layers by ameloblasts and odontoblasts, respectively.
		In the preceeding "bell stage," the tooth germ consists of the enamel organ (of ectodermal origin) with an outer and inner enamel epithelium, the dental papilla (of mesenchymal origin) with an inner and outer layer of cells, and the dental sac.
		Contact of pre-ameloblasts with predentin induces their differentiation into ameloblasts, which begin amelogenesis or apposition of enamel matrix.
	www.nature.com /ng/journal/v27/n2/fig_tab/ng0201_129_F1.html (177 words)

	WSAVA 2001 - Odontogenic Tumours
		The classic histological appearance of an ameloblastoma is a follicular arrangement of ameloblasts and stellate reticulum cells, resembling the basic structure of the enamel organ.
		The term ameloblastic odontoma is occasionally encountered in the veterinary literature.
		An ameloblastic odontoma is an ameloblastoma with focal differentiation into an odontoma.
	www.vin.com /VINDBPub/SearchPB/Proceedings/PR05000/PR00072.htm (1202 words)

	Amelogenin Gene Expression in Porcine Odontoblasts -- Oida et al. 81 (2): 103 -- Journal of Dental Research
		The secretory ameloblast layer was dissected from the inner surface of the removed enamel organ epithelia (EOE), and the maturation ameloblast layer was prepared from the labial surface of the incisor.
		Lane 1, oral epithelium; lane 2, muscle; lane 3, connective tissue; lane 4, dental pulp cells; lane 5, secretory ameloblasts from the incisor; lane 6, secretary ameloblasts from the molar; lane 7, maturation ameloblasts from the incisor; lane 8, odontoblasts from the incisor; and lane 9, odontoblasts from the molar.
		Lane 1, secretory ameloblasts in the molar; lane 2, secretory ameloblasts in the incisor; lane 3, maturation ameloblast in the incisor; lane 4, odontoblasts in the molar; and lane 5, odontoblasts in the incisor.
	jdr.iadrjournals.org /cgi/content/full/81/2/103 (3218 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		This suggests that the ameloblasts are programmed to secrete a defined amount of enamel matrix before entering the maturation stage and that a feedback from the enamel extra-cellular matrix to the ameloblast cells is present during enamel secretion.
		These observations suggest that enamel biomineralization is controlled at three hierarchical levels; first the timing of developmental processes and tooth eruption, secondly the ameloblast function and migration that produces the thickness and shape of the enamel, and lastly the matrix composition that modulates enamel crystal mineralisation.
		This means that the secretory ameloblasts must, in addition to matrix secretion, have a rapid turnover of certain structural components of the cell wall like cell surface antigens, receptors, adhesion molecules and junctional elements.
	www.leeds.ac.uk /dental/enamel/petter.html (434 words)

	Full-length Sequence, Localization, and Chromosomal Mapping of Ameloblastin -- Krebsbach et al. 271 (8): 4431 -- ...
		The enamel matrix, secreted by the ameloblast, is composed of two classes of proteins termed the amelogenins and the enamelins ( 12).
		Diffuse staining was seen in the superficial enamel layer near the mature ameloblasts, a region that is mainly composed of homogenous enamel matrix.
		The persistent expression of ameloblastin in the cytoplasm of mature ameloblasts and the dispersed positive reaction of ameloblastin in the superficial enamel layer near post-secretory ameloblasts support the notion that ameloblastin could play a role in enamel mineralization.
	www.jbc.org /cgi/content/full/271/8/4431 (3869 words)

	A correlated scanning and transmission electron microscopic study of maturation ameloblasts in developing molar teeth ... (Site not responding. Last check: 2007-11-06)
		Maturation ameloblasts of developing molar teeth of the rate were studied by both scanning and transmission electron microscopy.
		Elsewhere the proximal junctions of ameloblasts are not present and free communication between the extracellular spaces is evident.
		The lateral surface of ameloblasts exhibits a variety of surface configurations similar to but not as pronounced as those reported previously in rat incisor maturation ameloblasts.
	www.arclab.org /medlineupdates/abstract_455407.html (234 words)

	Ameloblastin is a cell adhesion molecule required for maintaining the differentiation state of ameloblasts -- Fukumoto ...
		was down-regulated in secretory stage ameloblasts ( Maas and Bei, 1997).
		sr, stellate reticulum; si, stratum intermedium; ab, ameloblast.
		Because ameloblasts detach from the matrix in the absence of
	www.jcb.org /cgi/content/full/167/5/973 (5346 words)

	The Cadherin-Catenin Complex Is Expressed Alternately with the Adenomatous Polyposis Coli Protein During Rat Incisor ...
		The observed E-cadherin expression was localized at the basal junctional complexes of smooth-ended ameloblasts and the apical borders of ruffle-ended ameloblasts.
		Staining was particularly intense at the periphery of the cells and at the apical and basal junctional complexes of the ameloblasts.
		Karim A, Warshawsky H (1979) The effect of colcemid on the structure and secretory activity of ameloblasts in the rat incisor as shown by radioautography after injection of 3H-proline.
	www.jhc.org /cgi/content/full/48/3/397 (4295 words)

	ccmb_BITES
		The ameloblasts have different vectors of movement that help give rise to a 3-dimensional continuum of protein deposition and subsequent crystal growth.
		Oldak and Fincham’s approach is not to let ameloblasts carry on the business of making their own enamel but rather to control the individual steps of biomineralization at the biochemical level.
		begin to form, ameloblasts and odontoblasts produce proteins that were originally thought to be specific to one cell type and not the other.
	www.usc.edu /hsc/dental/ccmb/pages/Bits/2000fw/Achievement.htm (4638 words)

	Gene expression in tooth: references
		Adenomatous polyposis coli protein is expressed in alternate stages of the ameloblast life cycle.
		Using a monoclonal antibody to study APC expression in the forming rat incisor, we found no APC staining in differentiating ameloblasts, then strong staining in secreting ameloblasts and stratum intermedium cells, followed by cells in the transition stage which did not stain.
		We report a unique system in which APC expression is upregulated and downregulated twice during the normal life cycle of ameloblasts.
	bite-it.helsinki.fi /REF250.HTM (242 words)

	Scientists uncover secret to sharp teeth
		While it is well established that cells called ameloblasts secrete enamel, the molecular signals regulating asymmetric ameloblast differentiation from the underlying dental epithelium are not well understood.
		The researchers found that follistatin was expressed at low levels in active ameloblasts and at much higher levels in the dental epithelial cells lining the enamel-free surface of the incisors.
		While the mechanism that dampens follistatin expression in unknown, it is clear that the lack of follistatin allows BMP signals to stimulate ameloblast differentiation on the labial side of the incisor.
	www.eurekalert.org /pub_releases/2004-11/cp-sus110204.php (303 words)

	Shh signaling within the dental epithelium is necessary for cell proliferation, growth and polarization -- Gritli-Linde ...
		a, ameloblasts; ode, outer dental epithelium; si, stratum intermedium; sr, stellate reticulum.
		In control molars, cyclin D1 expression is lost in post-mitotic ameloblasts facing the first layer of predentin matrix in the most advanced cusp (red arrow in C), whereas preameloblasts and the overlying stratum intermedium (fl arrowhead in C) facing post-mitotic odontoblasts (fl arrow in C) continue to express cyclin D1.
		for induction of ameloblast cytodifferentiation by the mesenchymal
	dev.biologists.org /cgi/content/full/129/23/5323 (8817 words)

	Transcription factor Sp3 is essential for post-natal survival and late tooth development (Site not responding. Last check: 2007-11-06)
		At low power magnification, the developing tooth of wild-type mice shows a continuous row of ameloblasts ('Am', arrow) and odontoblasts ('Od', arrow) interrupted by small vessels interspersed between the odontoblasts (fl arrowheads in C).
		Between the ameloblasts and odontoblasts, a sheet of pink and purple stained material that contains dentin and enamel is visible (marked in A and C by two white arrowheads).
		This layer of secretory products has been disrupted from the ameloblasts, leaving an artificial space (asterisks in A and C) that is regularly observed in wild-type mice of this age, but not in Sp3 null mice.
	www.nature.com /emboj/journal/v19/n4/fig_tab/7592176f6.html (279 words)

	British Journal of Biomedical Science: Apoptosis in developing rat teeth: A preliminary report
		TUNELpositive cells were found not only in ameloblasts and odontoblasts, but also in the stellate reticulum, the outer enamel epithelium, on the surface of the developing bony alveolar ridge, and in the pulpal and periodontal tissues.
		Traditionally, it is considered that ameloblasts remain vital until the full thickness of enamel has been laid down and virtually calcified.
		In contrast to ameloblasts, odontoblasts retain the ability to lay down fresh matrix, and may be stimulated to produce secondary, albeit atubular, dentine.
	www.findarticles.com /p/articles/mi_qa3874/is_199809/ai_n8825723 (1324 words)

	Tramadol, buy tramadol, antibiotics, Weight Loss drugs, weight loss herbs, weight loss herbal formula, weight loss, ... (Site not responding. Last check: 2007-11-06)
		No evident changes were observed at the stage of division and proliferation of ameloblasts after parathyroidectomy.
		In the ameloblasts at the stage of matrix formation and maturation, vacuoles of various sizes were observed, and increases in number and growth in size were seen chronologically.
		Calcium value at the site of enamel tubules was one fiftieth as much as that of normal rats on the ameloblastic side after 5 weeks of parathyroidectomy and was reduced to one-half at intermediate site.
	hair-loss-alopecia.com /ref-hair-growth/hair-growth-research-abs3.369.html (888 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		Morphological and cytochemical studies have suggested that maturation ameloblasts participate in protein loss by absorbing and degrading enamel proteins as the enamel matures.
		The amount of labelled enamel protein was higher in maturation ameloblasts than transitional ameloblasts.
		These findings support the hypothesis that maturation ameloblasts actively resorb and degrade enamel matrix proteins during enamel formation in the mandibular incisor of the rat.
	www.elsevier.com /cdweb/journals/00039969/articles/43/10/S000399699800055.abstract.en (161 words)

	[No title] (Site not responding. Last check: 2007-11-06)
		Abstract : The terminal differentiation of ameloblasts is preceded by a complex histogenesis of the enamel organ leading to the appearance of the stellate reticulum, stratum intermedium (SI), the inner dental epithelium (IDE) and outer dental epithelium (ODE).
		The maturation of the SI parallels the differentiation of ameloblasts.
		The SI could play a role in the modulation of IDE cell phenotype and in stabilizing the relative position of ameloblasts through the numerous desmosomes that interconnect all SI cells and SI cells with ameloblasts (1).
	www.leeds.ac.uk /dental/enamel/herve.html (428 words)

	Enamelysin (Matrix Metalloproteinase 20)-deficient Mice Display an Amelogenesis Imperfecta Phenotype -- Caterina et al. ...
		ameloblasts of the enamel organ and the odontoblasts of the dental
		Conversely, enamel matrix in null mice persisted, an abnormally thick layer of protein separated the ameloblasts from the enamel surface ( I), and nodule-like formations surrounded by ameloblasts were observed ( I, arrows).
		Interestingly, during the late maturation stage, the ameloblasts of the null mouse sometimes surrounded abnormal nodule structures.
	www.jbc.org /cgi/content/full/277/51/49598 (4719 words)

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