Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ODONTOBLASTS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed1996

Calbindin-D9k and calbindin-D28k expression in rat mineralized tissues in vivo.

Following their terminal differentiation, highly specialized cells, ameloblasts, odontoblasts, and osteoblasts sequentially elaborate mineralized tissues. While the developmental expression pattern of matrix proteins has been studied extensively, less attention has been paid to the molecules involved in calcium handling, such as calcium-binding proteins. This shortcoming, as well as previous conflicting data, led us to conduct studies on calbindin-D9k and calbindin-D28k in rat mandibular bone and incisor based on several methods established on rat ameloblasts in vivo. Radioimmunoassays showed that calbindin-D28k accounts for approximately 0.1% of cytosolic proteins in the ectomesenchymal fraction and 1% in the epithelial fraction of the rat incisor and is 100-fold more concentrated than calbindin-D9k in both tissue types. Western blot analysis confirmed that the anticalbindin-D28k reactive species corresponded to the well characterized renal calbindin-D28k in the ectomesenchyme. In this tissue, calbindin-D28k was ultrastructurally immunolocalized in the odontoblasts. Quantitative immunocytochemistry showed that labeling was distributed throughout their nucleus and cytoplasm. The similar cytoplasmic distribution of both calbindin-D proteins and mRNAs suggests that their expression is regulated at the subcellular level. In particular, immunoreactive calbindin-D28k appeared to be associated with rough endoplasmic reticulum. Calbindin-D9k antisense probe showed negligible labeling in odontoblasts, in parallel with the protein quantities measured (approximately 10 ng/mg of total protein). Finally, in situ hybridization showed transcripts for both calbindins-D in ameloblasts and also in osteoblasts. In summary, the present results support the concept that an elevated expression of these vitamin D-dependent calcium-binding proteins may characterize the phenotype of cells directly involved in the elaboration of mineralized tissues, enamel, dentine, and bone.

Age Factors↗
PubMed2003

Ultrastructural changes in feline dental pulp with periodontal disease.

A light and transmission electron microscopic study was conducted on dental pulp on cats suffering periodontal disease. After extraction, pulp tissues were fixed and embedded in Epon-Araldite. Thick layers of predentin (50 microm) and odontoblasts (30 microm) were observed. In thin sections, odontoblasts showed many mitochondria and secretary vesicles. Some capillaries with several fenestrations were located within the odontoblastic layer. All the sections of pulp examined displayed a generalized infiltration of chronic inflammatory cells. Fibroblasts displayed lytic changes in some areas. These findings imply that the pulp is significantly affected by periodontal disease and furcation-involved teeth should be a carefully considered factor when dental treatment is planned.

Animals↗
PubMed2000

Dental cells express factors that regulate bone resorption.

Odontoblasts and osteoblasts produce similar highly mineralized extracellular matrices. In bone, osteoblasts/stromal cells regulate osteoclast (ocl) formation and bone resorption by producing factors like osteoprotegerin (OPG), osteoclast differentiating factor (ODF/RANKL), and macrophage colony-stimulating factor (M-CSF) that interact with hematopoietic ocl precursor cells. Using odontoblast and pulp cell lines, we detected a constitutive expression of OPG, RANKL, and M-CSF mRNA in both cell types. OPG and RANKL proteins were also detectable. In vivo, RANKL and OPG were localized to odontoblasts, ameloblasts, and pulp cells in developing mouse teeth by immunohistochemistry. In a coculture system, we found the dental cells to be inhibitory to ocl formation from spleen and bone marrow precursors, despite their production of osteoclast stimulatory factors. Our data indicate for the first time that dental cells express factors important in regulation of osteoclastogenesis and bone resorption. Since both stimulatory (RANKL, M-CSF) and inhibitory (OPG) factors are expressed, a balance between positive and negative factors may contribute to regulation of bone resorption.

Animals↗
PubMed1975

Scanning electron microscopic studies of the rat incisor odontoblastema.

A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at minus 70 degrees C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron miscroscopic levels.

Animals↗
PubMed1981

Microprobe analysis of calcifying matrices and formative cells in developing mouse molars.

The distribution of Calcium and Phosphorus and of Na, K, S and Cl was studied in the mineralizing matrices and strata of ameloblasts and odontoblasts in developing mouse molars (5-14 days). Sections cut in a cryostat were prepared by freeze-drying and examined in an SEM by the method of energy dispersive x-ray analysis. In enamel a gradient of mineralization was observed with respect to age and topography. Progesssive loss of sulfur was also demonstrated. Less striking mineralization gradients were found in dentin. Predentin accumulated Ca at a concentration about 2% that of dentin and the Ca/P ratio was lower than that for apatite. Significant concentrations of calcium were localized in ameloblast and odontoblast strata. The concentration increased five-fold in ameloblasts as the cells matured and enamel mineralization entered the final phases, levels in odontoblasts remained stable. With age in both cellular strata, potassium counts decreased. In maturing ameloblasts the concentrations of sodium and chloride rose.

Ameloblasts↗
PubMed1989

Ultrastructural localization of dentine phosphoprotein in rat tooth germs by immunogold staining.

Dentine phosphoprotein (DPP) was localized on thin frozen sections of fixed rat tooth germs by indirect immunogold staining. Antisera were directed against DPP and against glutaraldehyde-treated DPP and were characterized by immuno-electroblotting. In odontoblasts, DPP was found to be localized in the cisternae of the rough endoplasmic reticulum (RER) and the Golgi apparatus and in Golgi-associated vesicles. Odontoblastic processes were moderately positive for DPP and dentine was intensely labeled on frozen sections of unfixed tissue. Predentine showed a slight immunoreactivity. These results indicate the synthesis of DPP in the RER, its accumulation in the Golgi apparatus and its vesicular transport and secretion via the odontoblastic processes into dentine. The close association of the gold particles with the dentinal collagen fibres makes a role of DPP in linking mineral to collagen conceivable. Matrix vesicles were negative for DPP, suggesting that the protein is not present at the sites of matrix vesicle-associated nucleation.

Animals↗
PubMed1979

Cathepsin D: ultra-immunohistochemical localization in dentinogenesis.

Cathepsin D was purified from rat liver using a new affinity chromatographic method, based on the coupling to the specific inhibitor pepstatin. This preparation was used for the production of specific antibodies from rabbit. The purified IgG fraction was conjugated to horseradish peroxidase in a two-step coupling procedure and used for electron microscopic immunohistochemistry of the odontoblast-predentine region of the rat incisor. Precipitates, indicating the presence of cathepsin D, were seen in the odontoblast, odontoblast process, and in the extracellular unmineralized matrix, the predentine. The observations are discussed in relation to proteoglycan degradation at the mineralization front simultaneous with crystal formation, and in relation to the function of lysosomal enzymes in the turnover of connective tissue.

Animals↗
PubMed1975

Effect of colchicine on the secretion of matrices of dentine and enamel in the rat incisor: an autoradiographic study using [3H]-proline.

Effects of colchicine on the incorporation of [3H]-proline into odontoblasts and ameloblasts at various development stages and on the secretion of the radioactive materials from these cells into dentinal and enamel matrices were studied autoradiographically, at 2,4,8 and 24 h after the injection of colchicine. In young functional and functional odontoblasts and ameloblasts, the number of autoradiographic silver grains over the cells increased while those over the matrices decreased 2,4, and 8 h after the injection of colchicine. However, the total number of grains over the cells and matrices were fairly uniform in all stages of cell development at all times after the injection of the drug. It is suggested that the drug does not appreciably affect the incorporation of [3H]-proline or the successive synthesis of the dentinal and enamel matrices but affects the secretion of the matrices in both functional odontoblasts and ameloblasts by interfering with the structure and function of microtubules in these cells.

Ameloblasts↗
PubMed1987

Effects of parathyroid hormone on odontogenesis of the mouse embryonic molar tooth in vitro.

Mandibular first molars of 17-day-old mouse embryos were cultured in vitro to examine the histological effects of various concentrations of parathyroid hormone (PTH) on odontogenesis of the molars. PTH did not affect the cytodifferentiation of mesenchymal cells into preodontoblasts but inhibited that of preodontoblasts into odontoblasts. Consequently, the odontoblasts failed to undergo dentinogenesis. On the other hand, inner enamel epithelium achieved terminal cytodifferentiation into secretory ameloblasts and these cells partially formed enamel in spite of the absence of dentin. All treated molars showed the same histological disturbances and these effects were independent of PTH dose. The present study indicated that PTH had an influence on mesenchyme-derived cells, inhibiting both the differentiation of odontoblasts and the formation of predentin and dentin.

Ameloblasts↗
PubMed1987

Hormone-responsive cells derived from human dental papilla: characterization in vitro and in vivo in diffusion chambers.

Cells of the dental papilla are capable of odontoblastic, fibroblastic, and endothelial differentiation and formation of dentin and the dental pulp. In the present study dental papilla cells, obtained from human tooth buds (HDP cells), were cultured in vitro through 3 to 7 passages. After exposure to prostaglandin E2 there was a marked decrease in intracellular cyclic AMP (cAMP) levels as compared to hormone-free controls. Parathyroid hormone and calcitonin had stimulatory effects with 1 and 2 log increases in cAMP, respectively. The HDP cells showed moderate activity of alkaline phosphatase, 1 log higher than that of hamster kidney fibroblasts (BHK 13) and 1 log lower than that of osteoblastic osteosarcoma cells (ROS 17/2). When cultured for 4 or 8 wk in diffusion chambers (DC) implanted in athymic mice, many of the HDP cells underwent odontoblastic morphodifferentiation with very long, single processes extending into the matrix. This matrix contained banded and unbanded collagen fibers. Neither light nor electron microscopy of the DC content revealed mineral deposits. These results suggest that HDP cells have an intrinsic potential for partial odontoblastic differentiation; inductive signals like those originating from odontogenic epithelium are probably essential for the completion of hard tissue formation.

Alkaline Phosphatase↗
PubMed1998

Expression of the mRNA for types I and II interleukin-1 receptors in dental tissues of mice during tooth development.

Interleukin-1 (IL-1) can exert its pleiotropic effects on nearly every tissue by binding to its cognate receptor. Two types of IL-1 receptors have been identified. A large number of cell types have been shown to possess IL-1 receptors in vitro and in vivo, but few studies have addressed the question of expression in dental tissues in vivo. Using in situ hybridization in normal newborn, young and adult mice, we have examined the cellular distribution of both types of IL-1 receptors in dental tissues. In the ameloblast layer of incisors and molars, the mRNA for the type I IL-1 receptor (IL-1RI) and the type II IL-1 receptor (IL-1RII) was detected at the presecretory stage. The expression level markedly increased and remained during amelogenesis at the secretory stage. At the maturation stage, however, the transcripts for both IL-1RI and -II mRNA disappeared. Expression of IL-1RI and -II mRNA was also observed in odontoblasts after crown morphogenesis had been completed, and continued in these cells during dentinogenesis. No transcripts were detected in stratum intermedium cells and other cells in dental follicle, stellate reticulum, dental papilla, or pulp. Additionally, both types of IL-1R mRNA were also detected in osteoclasts on surfaces of alveolar bone. These results demonstrated for the first time that enamel-secreting ameloblasts and dentine-secreting odontoblasts express IL-1RI and -II mRNA, suggesting that IL-1 plays a regulatory role in the function of ameloblasts and odontoblasts during tooth development of mice.

Age Factors↗
PubMed1983

Electron microscopy of dentinal tubule sclerosis in the enamel-free region of the rat molar.

Ultrastructural changes in dentinal tubule contents were followed for periods up to 6 weeks following tooth eruption into the mouth. Characteristic odontoblast processes were observed in some tubules throughout the enamel-free dentine. Many dentinal tubules contained shrunken odontoblast processes, large collagen fibres and/or accumulations of mineral in various forms. The mineralization patterns suggest mechanisms of tubule occlusion other than simple formation of peritubular dentine. Both the degenerating odontoblast processes and collagen fibres appear to provide an organic framework for deposition of mineral. This region of rat molar dentine is recommended as useful for study of naturally-occurring tubular sclerosis.

Animals↗
PubMed1985

An ultrastructural study of cytodifferentiation in the developing human root-tip.

Transmission electron microscopy showed that in growing human teeth, the root sheath consisted of inner and outer epithelial cells. The inner epithelial cells formed a basal lamina associated filamentous layer which increased in density in coronal direction. Extensions of developing odontoblasts were in contact with the basal lamina. Direct contact with the epithelial plasmalemma was not observed. The odontoblasts obtained their fully-developed cylindrical appearance after making contact with the basal lamina of the inner epithelial cells. But, they possessed already abundant RER before these contacts were present, indicating that the differentiation of dental papillary cells into collagen-producing cells did not require heterotypic epithelio-mesenchymal contacts. After deposition of dentine, the odontoblast processes were withdrawn from the epithelium and the outer layer of root dentine. Differentiation of cementoblasts was observed in the dental follicle in which mesenchymal cells develop into RER-containing cells, migrating through apical root-sheath fenestrations to their final position between the continuous root sheath and outer dentinal layer. The findings suggest that all differentiation steps of odontogenic epithelium and odontogenic papillary and follicular mesenchyme proceed without actual contact between epithelium and mesenchyme.

Bicuspid↗
PubMed1987

A radioautographic study of the effects of vinblastine on the fate of injected 45calcium and [125I]-insulin in the rat incisor.

To examine the effect of vinblastine on the movement of calcium and macromolecules through the enamel organ in the secretion zone and through the odontoblast layer, 45CaCl2 and [125I]-insulin were used as radioautographic tracers. Vinblastine did not alter the localization of either labelled Ca or insulin in the enamel organ and underlying enamel, but eliminated both labels in the pulp, odontoblasts and dentine. It is concluded that vinblastine has no effect on the passage of Ca and macromolecules in the enamel organ and secretory ameloblast layers, whereas its effect on the pulp and odontoblasts prevents passage of these tracers into the predentine and dentine.

Animals↗
PubMed1992

Immunocytochemical localization of growth hormone receptor in rat maxillary teeth.

To address the question of what role growth hormone may have in stimulating tooth formation, the distribution of its receptor/binding protein in developing rat incisors and molars was studied immunocytochemically using well-characterized monoclonal antibodies. Ten female 45-day-old Wistar rats were perfused with 4% paraformaldehyde. Five-microns paraffin sections of the growing end of maxillary incisors and molars were cut, deparaffinized and incubated with mouse anti-growth hormone receptor antibodies or control antibodies. A three-layer streptavidin peroxidase technique was used to detect bound antibody. Immunoreaction product was associated primarily with the cytoplasm of cells at certain stages of differentiation. Dividing cells, differentiating preameloblasts and preodontoblasts, secretory ameloblasts and odontoblasts showed immunoreactivity. Undifferentiated dental epithelium cells, stellate reticulum, external dental epithelial cells, mature odontoblasts, and most of cells in the dental papilla were non-reactive. However, at certain stages of tooth development, the stratum intermedium and the external dental epithelium also stained positively. The presence of growth hormone receptor/binding protein in tooth cells at different stages of their development indicates that growth hormone may influence cell proliferation, differentiation and differentiated functions of ameloblasts, odontoblasts and cementoblasts independent of a systemic mediator, and thus may be involved in stimulating odontogenesis directly.

Ameloblasts↗
PubMed1992

Transforming growth factor-beta 1 mRNA in neonatal ovine molars visualized by in situ hybridization: potential role for the stratum intermedium.

Human dentine contains relatively large amounts of transforming growth factor-beta (TGF-beta), which might originate from odontoblasts. The expression of the TGF-beta 1 message in developing teeth was examined by in situ hybridization. The analysis was made on 5-microns serial sections of mandibular third molars of neonatal sheep cut from tissues that had been fixed in glutaraldehyde and paraffin-embedded. A 35S-labelled cRNA probe, complementary to TGF-beta 1 mRNA, was constructed from human TGF-beta 1 cDNA. Northern analysis of total RNA from sheep placenta and neonatal third molars demonstrated hybridization to a single 2.4 kb TGF-beta 1 transcript from both tissues, indicating cross-reactivity of the human probe in the sheep. In the neonatal molars, in situ hybridization was observed in cells of the inner enamel epithelium, mature ameloblasts and mature odontoblasts, but not within preodontoblasts before dentine matrix formation. TGF-beta 1 mRNA expression was also evident in the cells of the dental papilla but scarcely so in the stellate reticulum. The most striking feature was the appearance of hybridization signal in the cells of the stratum intermedium before hybridization was evident in the inner enamel epithelium. Control sections incubated with RNAase before incubation with probe did not show evidence of hybridization. These findings suggest that TGF-beta 1 may have an important regulatory role in the differentiation of ameloblasts and odontoblasts, perhaps by modulating matrix formation during amelogenesis or odontogenesis. They also suggest a potential novel regulatory role for the cells of the stratum intermedium.

Ameloblasts↗
PubMed1992

A histochemical study by light and electron microscopy of the distribution of dipeptidyl peptidase-IV activity in the human dental pulp.

This activity was demonstrated in blood vessels, fibroblast-like cells, odontoblasts and Schwann cells surrounding non-myelinated axons. It was present on both the luminal and abluminal plasma membrane of endothelial cells. The plasma membrane of fibroblast-like cells and their processes had patches of fine electron-dense end-product corresponding to DPP-IV activity, while the plasma membrane of odontoblasts was loaded with a consistent reaction product. DPP-IV activity in the non-myelin-forming Schwann cells was in the plasma membrane of the free surface in contact with the extracellular matrix as well as in the plasma membrane in close contact with the axolemma. The plasma membrane of Schwann cells producing myelin sheath had no positive reaction for DPP-IV. The DPP-IV activity in the plasma membrane of fibroblast-like cells and odontoblasts may be associated with fibronectin-mediated adhesion to collagen, whereas the membrane-bound DPP-IV activity in endothelium and non-myelin-forming Schwann cells may be involved in cleavage of neuropeptides of other biologically active peptides.

Blood Vessels↗
PubMed1994

Immunocytochemical localization of choline-phospholipids in postnatal mouse molars.

This localization was studied using anti-choline phospholipid monoclonal IgM antibody (MC22-33F). By immunofluorescence, the apical portions of enamel-secreting ameloblasts and dentine-secreting odontoblasts were positively stained with MC22-33F. By immunoelectron microscopy, lysosomes in preodontoblasts, odontoblasts, preameloblasts and ameloblasts as well as matrix vesicles in dentine were strongly stained with MC22-33F. On the other hand, plasma membrane of these cells did not stain with MC22-33F. The frequency of positively reacting lysosomes in ameloblasts and odontoblasts and of matrix vesicles increased with cell maturation and mineral deposition.

Ameloblasts↗