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Kim J, Zhang H, Seymen F, Koruyucu M, Hu Y, Kang J, Kim YJ, Ikeda A, Kasimoglu Y, Bayram M, Zhang C, Kawasaki K, Bartlett JD, Saunders TL, Simmer JP, Hu JC. Mutations in RELT cause autosomal recessive amelogenesis imperfecta. Clin Genet 2019; 95:375-383. [PMID: 30506946 PMCID: PMC6392136 DOI: 10.1111/cge.13487] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 11/26/2018] [Accepted: 11/27/2018] [Indexed: 12/16/2022]
Abstract
Amelogenesis imperfecta (AI) is a collection of isolated (non-syndromic) inherited diseases affecting dental enamel formation or a clinical phenotype in syndromic conditions. We characterized three consanguineous AI families with generalized irregular hypoplastic enamel with rapid attrition that perfectly segregated with homozygous defects in a novel gene: RELT that is a member of the tumor necrosis factor receptor superfamily (TNFRSF). RNAscope in situ hybridization of wild-type mouse molars and incisors showed specific Relt mRNA expression by secretory stage ameloblasts and by odontoblasts. Relt-/- mice generated by CRISPR/Cas9 exhibited incisor and molar enamel malformations. Relt-/- enamel had a rough surface and underwent rapid attrition. Normally unmineralized spaces in the deep enamel near the dentino-enamel junction (DEJ) were as highly mineralized as the adjacent enamel, which likely altered the mechanical properties of the DEJ. Phylogenetic analyses showed the existence of selective pressure on RELT gene outside of tooth development, indicating that the human condition may be syndromic, which possibly explains the history of small stature and severe childhood infections in two of the probands. Knowing a TNFRSF member is critical during the secretory stage of enamel formation advances our understanding of amelogenesis and improves our ability to diagnose human conditions featuring enamel malformations.
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Affiliation(s)
- Jung‐Wook Kim
- Department of Pediatric Dentistry & Dental Research Institute, School of DentistrySeoul National UniversitySeoulRepublic of Korea
- Department of Molecular Genetics & the Dental Research Institute, School of DentistrySeoul National UniversitySeoulRepublic of Korea
| | - Hong Zhang
- Department of Biologic and Materials SciencesUniversity of Michigan School of DentistryAnn ArborMichigan
| | - Figen Seymen
- Department of Pedodontics, Faculty of DentistryIstanbul UniversityIstanbulTurkey
| | - Mine Koruyucu
- Department of Pedodontics, Faculty of DentistryIstanbul UniversityIstanbulTurkey
| | - Yuanyuan Hu
- Department of Biologic and Materials SciencesUniversity of Michigan School of DentistryAnn ArborMichigan
| | - Jenny Kang
- Department of Pediatric Dentistry & Dental Research Institute, School of DentistrySeoul National UniversitySeoulRepublic of Korea
| | - Youn J. Kim
- Department of Molecular Genetics & the Dental Research Institute, School of DentistrySeoul National UniversitySeoulRepublic of Korea
| | - Atsushi Ikeda
- Division of BiosciencesThe Ohio State University, College of DentistryColumbusOhio
| | - Yelda Kasimoglu
- Department of Pedodontics, Faculty of DentistryIstanbul UniversityIstanbulTurkey
| | - Merve Bayram
- Department of Pedodontics, Faculty of DentistryIstanbul Medipol UniversityIstanbulTurkey
| | - Chuhua Zhang
- Department of Biologic and Materials SciencesUniversity of Michigan School of DentistryAnn ArborMichigan
| | - Kazuhiko Kawasaki
- Department of AnthropologyPenn State UniversityUniversity ParkPennsylvania
| | - John D. Bartlett
- Division of BiosciencesThe Ohio State University, College of DentistryColumbusOhio
| | - Thomas L. Saunders
- Department of Internal Medicine, Division of Molecular, Medicine and GeneticsUniversity of Michigan Medical SchoolAnn ArborMichigan
| | - James P. Simmer
- Department of Biologic and Materials SciencesUniversity of Michigan School of DentistryAnn ArborMichigan
| | - Jan C‐C. Hu
- Department of Biologic and Materials SciencesUniversity of Michigan School of DentistryAnn ArborMichigan
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2
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Grewe JM, Felts WJ. Influence of Occlusion on the Cellular Activity of Mouse Mandibular Incisors. J Dent Res 2016. [DOI: 10.1177/00220345680470012901] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The influence of occlusion on cellular activity of mouse mandibular incisors was evaluated by determining the age at the time of eruption and initial occlusal contact and by correlating this information with the ratio of tritiated thymidine-labeled cells of the various cell populations at different stages of eruption and occlusion.
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Affiliation(s)
- John M. Grewe
- School of Dentistry and School of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - William J.L. Felts
- School of Dentistry and School of Medicine, University of Minnesota, Minneapolis, Minnesota
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3
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Minicucci EM, Lopes LF, Crocci AJ. Dental abnormalities in children after chemotherapy treatment for acute lymphoid leukemia. Leuk Res 2003; 27:45-50. [PMID: 12479851 DOI: 10.1016/s0145-2126(02)00080-2] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The frequency of dental abnormalities, such as delayed dental development, microdontia, hypoplasia, agenesis, V-shaped root and shortened root was evaluated in 76 acute lymphoblastic leukemia (ALL) pediatric patients who had been off chemotherapy for 6 months. These children had been subjected to one of the three Brazilian Protocols or the BFM86 Protocol. The patients were divided into three groups: Group I (GI; high risk) treated with one of the three Brazilian Protocols who received high-dose chemotherapy, intensive maintenance and cranial radiotherapy; Group II (GII; low risk) who were also treated with one of the three Brazilian Protocols using low-intensive chemotherapy with no radiotherapy; and Group III (GIII) based on the BFM86 Protocol. Of 76 children, 13 showed no dental abnormalities (8 were at the age of tooth formation). The remaining 63 children (82.9%) showed at least one dental anomaly. The abnormalities were probably caused by the type, intensity, frequency of the treatment and age of the patients at ALL diagnosis and this might have important consequences for the children's dental development.
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Affiliation(s)
- Eliana Maria Minicucci
- Department of Pathology, School of Medicine of Botucatu, São Paulo State University, SP, São Paulo, Brazil.
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4
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Abstract
BACKGROUND The production of monoclonal antibodies to cell cycle-related molecules provides the basis for immunochemical studies on cell kinetics. METHODS Immunocytochemistry permits the tissue localization of replicating cells, whereas flow cytometry defines the exact position of immunoreactive cells in the cell cycle and ensures a quantitative analysis of the growth fraction. Bromo-deoxyuridine-antibody can be used to reveal S phase-traversing cells, whereas the immunoreactivity for the Proliferating Cell Nuclear Antigen defines the G1, S, and G2-M subpopulations of the cell cycle. RESULTS Odontogenic cells produce secretory products (e.g., enamel and dentine matrix proteins and growth factors) and express receptors and oncogenes during specific stages of their differentiation. CONCLUSIONS The simultaneous detection of cell cycle-related antigens and differentiation markers using double immunochemical staining may be useful to clarify the role of putative regulatory molecules in the control of cell growth during odontogenesis, thus unveiling molecular mechanisms that regulate developmental dynamics.
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Affiliation(s)
- A Casasco
- Institute of Histology & Embryology, University of Pavia, Italy
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5
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Abstract
(1) Although our knowledge on teeth and tooth nerves has increased substantially during the past 25 years, several important issues remain to be fully elucidated. As a result of the work now going on at many laboratories over the world, we can expect exciting new findings and major break-throughs in these and other areas in a near future. (2) Dentin-like and enamel-like hard tissues evolved as components of the exoskeletal bony armor of early vertebrates, 500 million years ago, long before the first appearance of teeth. It is possible that teeth developed from tubercles (odontodes) in the bony armor. The presence of a canal system in the bony plates, of tubular dentin, of external pores in the enamel layer and of a link to the lateral line system promoted hypotheses that the bony plates and tooth precursors may have had a sensory function. The evolution of an efficient brain, of a head with paired sense organs and of toothed jaws concurred with a shift from a sessile filter-feeding life to active prey hunting. (3) The wide spectrum of feeding behaviors exhibited by modern vertebrates is reflected by a variety of dentition types. While the teeth are continuously renewed in toothed non-mammalian vertebrates, tooth turnover is highly restricted in mammals. As a rule, one set of primary teeth is replaced by one set of permanent teeth. Since teeth are richly innervated, the turnover necessitates a local neural plasticity. Another factor calling for a local plasticity is the relatively frequent occurrence of age-related and pathological dental changes. (4) Tooth development is initiated through interactions between the oral epithelium and underlying neural crest-derived mesenchymal cells. The interactions are mediated by cell surface molecules, extracellular matrix molecules and soluble molecules. The possibility that the initiating events might involve a neural component has been much discussed. With respect to mammals, the experimental evidence available does not support this hypothesis. In the teleost Tilapia mariae, on the other hand, tooth germ formation is interrupted, and tooth turnover ceases after local denervation. (5) Prospective dental nerves enter the jaws well before onset of tooth development. When a dental lamina has formed, a plexus of nerve branches is seen in the subepithelial mesenchyme. Shortly thereafter, specific branches to individual tooth primordia can be distinguished. In bud stage tooth germs, axon terminals surround the condensed mesenchyme and in cap stage primordia axons grow into the dental follicle.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- C Hildebrand
- Department of Cell Biology, University of Linköping, Sweden
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6
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Casasco A, Casasco M, Cornaglia AI, Mazzini G, De Renzis R, Tateo S. Detection of bromo-deoxyuridine- and proliferating cell nuclear antigen-immunoreactivities in tooth germ. Connect Tissue Res 1995; 32:63-70. [PMID: 7554937 DOI: 10.3109/03008209509013707] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The development of antibodies to cell cycle-related antigens provides the basis for immunochemical studies on cell kinetics. Bromo-deoxyuridine (BrdU) incorporated by S-phase traversing cells is an exogenous marker of replicating cells, whereas proliferating cell nuclear antigen (PCNA) is an endogenous marker of replicating cells. We have applied monoclonal antibodies to BrdU and PCNA to study cell kinetics in tooth germ by immunohistochemistry and flow cytometry. BrdU-antibody reacted only with S phase-traversing cells in pulse-labelling experiments, whereas PCNA-antibody reacted with G1, S and G2-M phases traversing cells. Although the number of PCNA-positive cells largely exceeded the number of BrdU-labelled cells, the pattern distribution of immunoreactive cells was similar using BrdU- and PCNA-antibodies as revealed by immunohistochemistry. The use of PCNA-antibody allowed the detection of proliferating cells also in human tooth germ. It is suggested that combined identification of BrdU and PCNA on one side and growth factors, oncoproteins or differentiation markers on the other side may constitute a useful approach to understand the mechanisms of cell differentiation in tooth germ.
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Affiliation(s)
- A Casasco
- Institute of Histology and Embryology, University of Pavia, Italy
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Abstract
Dentinogenesis can be initiated secondarily as an intrinsic ability of the dental pulp to repair, or after interaction of pulp cells with specific exogenous inductive factors. In the present article the basic developmental aspects, highlighting the mechanism by which dentinogenesis is initiated during tooth development, are discussed. Furthermore, clinical and experimental observations concerning the events taking place during secondary initiation of dentine formation, as part of exposed or non-exposed pulp tissue repair, or as a result of dentine matrix or other chemical-pulp cell interactions, are reviewed. Discussion includes hypotheses relating to the crucial biological steps leading to expression of odontoblastic-like cell phenotype and secondary initiation of dentine histogenesis.
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Affiliation(s)
- D Tziafas
- Department of Dental Pathology and Therapeutics, School of Dentistry, Aristotle University of Thessaloniki, Greece
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8
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Moule AJ, Young WG, Adkins KF. Early cellular events in an actinomycin D-created dentin niche in the rat incisor. J Oral Pathol Med 1993; 22:159-67. [PMID: 8315595 DOI: 10.1111/j.1600-0714.1993.tb01050.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Administration of actinomycin D at a dose level of 0.375 microgram/g resulted in the selective disruption of developing odontoblasts at a critical stage of morphogenesis. A dentin niche was formed which was later repaired by cellular reparative dentin. The cellular changes which resulted in dentin niche formation were studied histologically and ultrastructurally in serial longitudinal and transverse sections from tissues obtained 10 h to 80 h following injection of the drug. Five stages were identified: initial destruction (10-20 h), rapid destruction (30-40 h), debris removal (50-60 h), proliferation (60-80 h) and matrix deposition (post 80 h). The cellular changes found in the dental papilla were considerably different from those found in inflammation, resolution and repair of fibrous connective tissue. These early stages were dominated by apoptosis and heterophagy, and after 80 h by disordered dentin matrix formation. The three-dimensional morphology of the defect was reconstructed from serial sections. The shape of the niche was the result of interference by actinomycin D in the patterns of proliferation and migration of the cells in the apical region of the rat incisor tooth.
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Affiliation(s)
- A J Moule
- Department of Dentistry, University of Queensland, Brisbane, Australia
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9
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Young WG, Zhang CZ, Li H, Lobie PE, Waters MJ. A bromodeoxyuridine immunocytochemical and morphometric study of the influence of growth hormone on cell proliferation in odontogenic mesenchyme of the Lewis dwarf rat. Arch Oral Biol 1993; 38:207-14. [PMID: 8489414 DOI: 10.1016/0003-9969(93)90029-l] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Cell proliferation was studied in pre-odontoblasts, and in cells of the dental papilla and lingual dental follicle using bromodeoxyuridine immunocytochemistry and morphometry in Bouin's perfused and paraffin-embedded, undemineralized maxillary incisors. Cells in DNA synthesis, as shown by this technique, or in mitosis, were counted. Significantly fewer labelled nuclei, unlabelled nuclei and total nuclei were found in the tissues of growth hormone-deficient dwarf rats than in normal tissues. However, in dwarf rats treated for 6 days with bovine growth hormone, their numbers were equivalent to, or in some instances greater than those in normal tissues. The bromodeoxyuridine labelling index, the ratio of positive to negative nuclei and the mitotic index of pre-odontoblasts in dwarf rats were consistently lower than in normal rats, and were reversible by growth hormone. Growth hormone thus plays a part in odontogenic mesenchymal proliferation.
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Affiliation(s)
- W G Young
- Division of Oral Biology and Pathology, Faculty of Dentistry, University of Queensland, Australia
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Casasco A, Calligaro A, Casasco M. Proliferative and functional stages of rat ameloblast differentiation as revealed by combined immunocytochemistry against enamel matrix proteins and bromodeoxyuridine. Cell Tissue Res 1992; 270:415-23. [PMID: 1486596 DOI: 10.1007/bf00645042] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A double-staining immunocytochemical technique was used for the simultaneous detection, at the light- and electron-microscopical level, of proliferating bromodeoxyuridine (BrdU)-labelled cells and enamel protein (EP)-producing cells in the inner enamel epithelium (IEE) of rat tooth germ. BrdU-positive cells were found in the region of the IEE close to the cervical loop and never displayed EP-like immunoreactivity. BrdU-immunoreactivity was confined to the nucleus of replicating cells. In contrast, epithelial cells displaying EP-like immunoreactivity were found in the region of the forming dental cusp and were consistently BrdU-negative. EP-like immunoreactivity was detectable in the cytoplasmic compartments involved in the exocrine secretion pathway and in the extra-cellular matrix close to EP-immunoreactive cells. These data support the view that withdrawal from the cell cycle in the IEE is a temporal prerequisite for acquiring the functional competence of secreting EP. Moreover, cycling cells and secretory cells in the IEE constitute two separate compartments that are spatially defined, and that exhibit clear-cut staining patterns with respect to BrdU- and EP-immunoreactivity, respectively. We thus propose that BrdU-incorporation and EP-production may be used as specific markers of the differentiation of the IIE cells in studies of the possible role of growth factors, their receptors and oncoproteins in this tissue.
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Affiliation(s)
- A Casasco
- Institute of Histology and Embryology, University of Pavia, Italy
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11
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Geiger G, Hild A. [Micromorphologic studies of the odontoblasts of sheep in different development and maturation stages]. Anat Histol Embryol 1991; 20:320-33. [PMID: 1796784 DOI: 10.1111/j.1439-0264.1991.tb00307.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The fine tissue structure of ovine odontoblasts was studied in various developmental and maturational stages. Odontoblasts differentiate from the peripherally-located mesenchymal cells of the dental papilla. On the basis of cytological parameters, it was possible to divide the odontoblasts into the following groups: pre-odontoblasts, juvenile (light) odontoblasts and mature (dark) odontoblasts. The three maturational stages of odontoblasts exhibit substantial differences with respect to their form and to the number and arrangement of their cytoplasmatic organelles. Structural differences in the three cell types appear to be closely correlated to the level of cellular activity.
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Affiliation(s)
- G Geiger
- Medizinischen Zentrum für Zahn-, Mund- und Kieferheilkunde, Abteilung für Oralchirurgie und Zahnärztliche Poliklinik, Giessen
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12
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Fuenzalida M, Lemus R, Romero S, Fernandez-Valencia R, Lemus D. Behavior of rabbit dental tissues in heterospecific association with embryonic quail ectoderm. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 1990; 256:264-72. [PMID: 2250161 DOI: 10.1002/jez.1402560305] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The behavior of dental tissues from the rabbit, Oryctolagus cuniculus, in association with epithelium from the quail, Coturnix coturnix japonica, has been examined. Adult and embryo rabbits were employed in this study. Dental papillae from teeth at the cap stage from rabbit embryos and dental pulp from adult rabbits were isolated surgically and recombined with skin ectoderm from 72-hour-old quail embryos. The recombined tissues were cultured for 48 hours on semi-solid medium and subsequently removed and placed on chorio-allantoic membranes of 7-day-old chick embryos. Control cultures (dental pulp, dental papillae, and quail ectoderm) showed regression, atrophy, or differentiation according to the phenotype of the tissue. After 8 days in explant culture, heterologous recombinants composed of dental papillae and flank skin ectoderm from quail embryos developed differentiated chimeric tooth structures. It was unclear whether or not enamel was being secreted. The fact that the interactions between the enamel epithelium and the dental papillae are reciprocal is well known. The differentiation of odontoblasts can only occur in the presence of an enamel organ. Thus, the quail epithelium must have been induced to become an enamel organ, the lack of enamel proteins notwithstanding. Apical pulp and root pulp from adult rabbits plus quail ectoderm showed a high degree of regression and atrophy. At around 15 days of gestation, the rabbit dental papillae at the cap stage have already acquired odontogenic potential. By contrast, under the same experimental conditions, the dental pulp from continuous-growth teeth from adult rabbits did not show odontogenic potential.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Fuenzalida
- Department of Experimental Morphology, Medical School, University of Chile, Santiago
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13
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Casasco A, Calligaro A, Marchetti C, Poggi P, Brugnatelli S, Danova M, Fiocca R. Immunocytochemical detection of proliferating cells in the rat tooth germ by monoclonal antibodies against 5-bromo-2'-deoxyuridine. Arch Oral Biol 1989; 34:65-9. [PMID: 2783041 DOI: 10.1016/0003-9969(89)90047-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
5-Bromo-2'-deoxyuridine incorporated into DNA synthesizing cells in vivo is detected by a monoclonal antibody. The results are similar to those obtained with cytoautoradiography, but show variance with data from some past autoradiographic studies. This immunocytochemical technique may be a useful tool for study of cell kinetics in the oral tissues.
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Affiliation(s)
- A Casasco
- Istituto di Istologia ed Embriologia gen., University of Pavia, Italy
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14
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Rihtniemi L, Thesleff I. An autoradiographic study on the effect of epidermal growth factor on cell proliferation in erupting mouse incisors. Arch Oral Biol 1987; 32:859-63. [PMID: 3509746 DOI: 10.1016/0003-9969(87)90098-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Epidermal growth factor (EGF) is a small polypeptide that induces precocious eyelid opening and incisor eruption in newborn mice; it stimulates cell proliferation in various cell types in vitro and in vivo. EGF was injected twice daily into newborn mice (0.4 microgram/g) and tritiated thymidine was injected subcutaneously 6 h before killing the mice. Longitudinal sections of the lower incisors showed significantly more thymidine-labelled mitoses in the pre-odontoblast and pre-ameloblast layers at the basal ends of incisors in EGF-treated mice than in control mice. Although these results indicate that the EGF-induced precocious tooth emergence is associated with a stimulation of cell proliferation in the root sheath, this tissue may not be the target for the actions of EGF. Earlier studies have shown that root growth is not a factor in the generation of the eruptive force and, as neither the pre-ameloblasts nor pre-odontoblasts express EGF-receptors, the stimulation of cell proliferation in the root-sheath region appears to be a result and not a cause of accelerated tooth eruption, i.e. the increase in root growth may meet the need to maintain the tooth positionally during the accelerated eruptive process.
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Affiliation(s)
- L Rihtniemi
- Department of Pedodontics and Orthodontics, University of Helsinki, Finland
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15
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Chiego DJ, Klein RM, Avery JK, Gruhl IM. Denervation-induced changes in cell proliferation in the rat molar after wounding. Anat Rec (Hoboken) 1986; 214:348-52. [PMID: 3706780 DOI: 10.1002/ar.1092140403] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The dental pulp has the capacity to initiate and maintain repair after trauma. The purpose of the present study was to quantitatively analyze the role of the peripheral nervous system in regulation of pulpal cell proliferation in response to wounding. Six groups of ten rats were used in these studies. There was one baseline group (wounded, but innervation intact) and five resection groups. The resection groups included rats with unilateral superior cervical ganglionectomy (SCG), unilateral inferior alveolar nerve resection (IAN), unilateral chorda tympani (CT) resection, IAN + SCG, or a complete unilateral nerve resection (IAN + SCG + CT). One millimeter of enamel and dentin was removed from the first mandibular molar on the experimental (resected) side. Therefore, each rat had an experimental and control molar. Rats were killed at various intervals from day 0 to day 15 after wounding and received 0.5 muCi/g b.wt. 3H-thymidine 1 hour before death. For the baseline (innervation intact) data a peak in 3H-thymidine incorporation occurred at 5 days after wounding. In the resected groups, there was a general increase in the number of labeled cells at the zero time point, and a suppression of the 5-day peak with a delay in the proliferative response to wounding. The SCG + IAN-resected group maintained the lowest number of labeled cells throughout the entire experimental period compared to the experimental baseline data and the two controls. At the initial and termination points the SCG + IAN-resected groups demonstrated the highest number of labeled cells.(ABSTRACT TRUNCATED AT 250 WORDS)
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16
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Dahl JE, Kjaerheim A. Evaluation of rat incisor mesenchymal cells in bleomycin injected animals fixed by immersion or perfusion. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1985; 93:498-506. [PMID: 2419960 DOI: 10.1111/j.1600-0722.1985.tb01347.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Bleomycin was administered to four groups of rats in a single intravenous injection of 25 mg/kg, 50 mg/kg, 75 mg/kg and 100 mg/kg, respectively. The animals were killed by perfusion or by decapitation followed by immersion fixation at 24 h and 5 days after injection. Sections were made of maxillary incisors and evaluated by light microscopy. Bleomycin produced a transitory arrest of dividing cells resulting in an apparent synchronization of the cell population. Necrotic cells were found within the basal pulp and the preodontoblasts at 1 day observation time. After 5 days a dentinal lesion was observed at the two highest dose levels and the necrotic areas were filled in by proliferating adjacent cells. A better quality of fixation, especially of cells surrounded by dentin, was observed in perfusion fixed animals but the fixation procedure did not influence the alterations found in experimental animals.
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17
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Kim YS, Clark SA, Stumpf WE, DeLuca HF. Nuclear uptake of 1,25-dihydroxyvitamin D3 in developing rodent teeth: an autoradiographic study. Anat Rec (Hoboken) 1985; 212:301-6. [PMID: 3840659 DOI: 10.1002/ar.1092120313] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Target cells for 1,25(OH)2 vitamin D3 metabolites are identified in developing rodent teeth by the use of thaw-mount autoradiography. Following the injection of [26, 27-3H]-1,25(OH)2 vitamin D3 into 18-day- and 20-day-old fetal rats and neonatal mice, nuclear concentration of radioactivity is found in different cell types. In incisors of both animal groups, strong nuclear labeling is present predominantly in pulp cells, while relatively weakly labeled cells are found in the layers of odontoblasts, ameloblasts, and stratum intermedium. In molars, nuclear labeling is absent in fetal rats, but is present in 2-day-old neonates in pulp cells and cells in the layers of stratum intermedium of the first molars, but not in the second molars. The absence of labeled pulp cells in the progenitor regions of incisors and in molars of 20-day-old fetal rats, and differential ontogenic appearance of labeled pulp cells in molars, indicates that there is a critical period of receptor emergence. The finding that labeled pulp cells exist in the regions of incisors and molars where secretory odontoblasts are present suggests that nuclear uptake of 1,25(OH)2 vitamin D3 is related to cell maturation and differentiation, and topographically related to the formation of dentin. The results further suggest that, in contrast to bone, the predominant effect of 1,25(OH)2 vitamin D3 is not on tooth cells which are directly involved in the formation of calcified tissue, i.e., ameloblasts and odontoblasts, but rather on supporting tissues such as pulp cells and stratum intermedium.
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18
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Dahl JE, Strømme Koppang H. Renewal and migration of rat incisor mesenchymal cells after doxorubicin administration. Acta Odontol Scand 1985; 43:97-102. [PMID: 3863451 DOI: 10.3109/00016358509046493] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Ten female rats were intravenously injected with doxorubicin (20 mg/kg) and divided into two equal groups receiving a dose of tritiated thymidine either simultaneously with doxorubicin or 1 h before being killed after 5 days. Six control animals were correspondingly injected with 3H-thymidine. The left and right maxillary incisors were prepared for histologic and microautoradiographic investigation, respectively. The distribution of labeled cells in animals injected 1 h before death showed the regions of proliferation, whereas migration from these regions was evaluated by longer observation time. A zone of reduced dentin deposition lined by irregular odontoblasts being young odontoblasts and late preodontoblasts was observed at the time of doxorubicin injection. Pulpally to the dentinal lesion, islands of irregular predentin were deposited by non-progenitive pulp cells and depolarized odontoblasts. The late preodontoblasts were renewed from progenitive pulp cells, leading to a disturbed mantle predentin deposition.
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19
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Dahl JE. Proliferation and migration of rat incisor mesenchymal cells. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1983; 91:335-40. [PMID: 6579615 DOI: 10.1111/j.1600-0722.1983.tb00826.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Sixty female Wistar rats were injected with tritiated thymidine and killed at intervals between 1 hr and 72 hr after injection. Autoradiographs of paraffin and Vestopal W embedded sagittal sections of the maxillary incisors were prepared. The distribution of labeled cells after 1 hr revealed the basal pulp cells and the preodontoblasts as proliferative cells. The growth rate of the incisor and the migration of the basal pulp cells were established from the position of labeled cells at 72 hr observation time. The number and localization of labeled and unlabeled mitoses were registered in order to determine the duration of the generation cycle of the proliferative cells. The identical cell generation time of preodontoblasts and basal pulp cells and the migration pattern of the latter indicate that the preodontoblasts are renewed by preodontoblast multiplication and not by migration of basal pulp cells.
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Steigman S, Michaeli Y, Weinreb M, Zajicek G. Three-dimensional reconstruction of the rat incisor by means of computerized histomorphometry. Anat Rec (Hoboken) 1983; 205:455-64. [PMID: 6344695 DOI: 10.1002/ar.1092050410] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Kim YS, Stumpf WE, Clark SA, Sar M, DeLuca HF. Target cells for 1,25-dihydroxyvitamin D3 in developing rat incisor teeth. J Dent Res 1983; 62:58-9. [PMID: 6571855 DOI: 10.1177/00220345830620011301] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The concentration of radioactivity is observed in the nuclei of pulpal cells of maxillary and mandibular incisors of 20-day-old fetal rats, following injection of [3H]-1,25 (OH)2 vitamin D3. Cells in the odontoblast and ameloblast layers are essentially free of nuclear labeling. The radioactively labeled pulpal cells exist throughout the length of the incisors with the exception of the progenitor areas. The results indicate the presence of receptors for 1,25 (OH)2 vitamin D3 in pulpal cells, and suggest the effects of the hormone on these cells.
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Chiego DJ, Klein RM, Avery JK. Tritiated thymidine autoradiographic study of the effects of inferior alveolar nerve resection on the proliferative compartments of the mouse incisor formative tissues. Arch Oral Biol 1981; 26:83-9. [PMID: 6944031 DOI: 10.1016/0003-9969(81)90075-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Ohshima S, Chiba M. Changes in mitotic activity in the basal proliferative tissues after experimental shortening of the rat incisor. Arch Oral Biol 1981; 26:533-5. [PMID: 6947755 DOI: 10.1016/0003-9969(81)90012-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Stene T, Koppang HS. Autoradiographic investigation of proliferative responses in rat incisor pulp after vincristine administration. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1980; 88:96-103. [PMID: 6929564 DOI: 10.1111/j.1600-0722.1980.tb01200.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
-0.7 mg/kg VCR was given to nine rats in three experimental groups. Twenty-three hours after VCR injection the animals were injected with 3H-thymidine. The animals were sacrificed 24, 48 and 72 h after the VCR injection, and by comparison with nine control animals similarly injected with sodium chloride solution and nucleotide, it was shown that VCR causes a delayed migration of pulp cells from the proliferative pool and a small but distinct inhibition of the incisal growth of the incisors. The growth inhibition corresponded to the normal growth over a 24-h period in non-VCR-injected animals.
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Moe H, Thorball N, Nielsen HW. Structural alterations in proliferating, remodeling, and regressing tooth pulp arterioles. Cell Tissue Res 1979; 203:339-54. [PMID: 519725 DOI: 10.1007/bf00233263] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In the continuously growing upper incisor of 100 g rats about 25 arterioles arise from an artery outside the tooth and pass through the apical foramen to run parallel to one another in the central part of the pulp, each supplying a well-defined sector of the migrating odontoblast layer. The arterioles pass through a cycle of proliferation, growth, remodeling, regression and decay, phase displaced in relation to each other. Proliferative and degenerative processes occur in the arteriole wall throughout the cycle, but vary considerably in intensity at different phases. Proliferation takes place by mitosis in the endothelium and the innermost smooth muscle cells. The degenerative process consists of reduction in size of smooth muscle cells by partial autodigestion and by cell death. When the odontoblasts reach the incisal extremity of the tooth, they die, and the associated regressed arteriole disappears. The system of pulpal arterioles has remarkable spatio-temporal features and each of its vessels appears to be in a state of sensitive structural equilibrium.
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Abstract
Cellular reorganization in the pulp following mechanical pulp exposure involves three steps: First, lysis and macrophage resolution of the clot form; second, there is an invasion of the clot area by fibroblasts and endothelial cells, i.e., formation of granulation tissue; third, an organization and differentiation of these cells into functional odontoblasts occurs as early as 9 days after exposure. Autoradiographic results showed an increased DNA synthesis in the fibroblast and endothelial cell populations which coincided with a histologically-observed increase in those populations. A relative increase in fibroblastic activity, as compared to endothelial cell activity, suggested that fibroblasts may be the cells that replace odontoblasts.
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Koppang HS. Histomorphologic investigations of dentinogenesis in incisors of offspring of cyclophosphamide-treated pregnant rats. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1978; 86:444-58. [PMID: 284568 DOI: 10.1111/j.1600-0722.1978.tb00651.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eight days old offspring of six rats treated with single doses of 40 mg/kg and 50 mg/kg of cyclophosphamide on the 20th day of pregnancy constituted two experimental groups. Group 1 (40 mg/kg) comprised 21 animals, Group 2 (50 mg/kg) 14 animals. Histomorphologic investigations of the maxillary and mandibular incisors revealed the following changes: (1) dental constrictions, (2) niche-like dentinal defects, (3) scalloping of the amelodentinal junction, (4) incremental line in the pre-experimental tooth segment, (5) external resorptions, and (6) diffuse edema in the pre-experimental part of pulp. Constrictions and niches qualitatively concurred with those previously observed in adult rats of the same strain, but the lesion frequency was essentially higher in the offspring. Further, the additional change of external resorptions was evinced by the offspring incisors, and changes only rarely observed in adults, such as scalloping of the dentinoenamel junction and a dentinal incremental line, constituted frequent findings in the offspring material.
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Stene T. Effect of vincristine on odontoblasts in rat incisor. SCANDINAVIAN JOURNAL OF DENTAL RESEARCH 1978; 86:346-56. [PMID: 281755 DOI: 10.1111/j.1600-0722.1978.tb00637.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vincristine in doses of 0.1, 0.3, 0.5 and 0.7 mg/kg was administered to 60 rats in four groups. Histomorphologic investigation of the odontoblast population in the maxillary incisors revealed dose-dependent reactions consisting of (1) swelling of the odontoblasts and an accumulation of abnormal mitotic cells in the germinative parts of the pulp after 5 h, (2) a supervening necrosis and destruction of some odontoblasts and of the mitotic cells after 24 h, and (3) after 3 d, a reversal to normal structure in some parts of the odontoblast population, but a further development of the vincristine-induced changes, with severe cellular derangement and irregular predentin production, in others.
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Abstract
The turnover of collagen in the dental pulp was studied using H3-proline and microchemical techniques. The incorporation of label into the whole tissue was very high, with most of the label being incorporated into the noncollagenous substances. The rate of disappearance of label from collagen approximated the disappearance of label from noncollagenous components, suggesting that the whole pulp was undergoing rapid remodeling. There seems to be more than one metabolic pool of collagen.
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Abstract
The rodent incisor tooth is the site of five cell populations proliferating in harmony: amelocytes, odontocytes, pulp cells, endothelial cells and the periodontal ligament. Their proliferating regions are located in the apex tip, where the various cells originate. Cells displaced from the tooth origin at the apex toward the periphery, mature to perform their specified function. The proliferative events in the tooth are summarized in a conceptual model of the incisor proliferon. The proliferon is an oriented structure with an origin and periphery. It consists of four basic elements: parenchyma, connective tissue, blood vessels and nerve fibres, all interacting continuously. All four are indispensable in the definition of the proliferon.
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Smith CE, Warshawsky H. Movement of entire cell populations during renewal of the rat incisor as shown by radoioautography after labeling with 3H-thymidine. The concept of a continuously differentiating cross-sectional segment. (With an appendix on the development of the periodontal ligament). THE AMERICAN JOURNAL OF ANATOMY 1976; 145:225-59. [PMID: 1258806 DOI: 10.1002/aja.1001450206] [Citation(s) in RCA: 73] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Renewal of the rat incisor was studied in three dimensions by employing a serial cross-sectioning technique to locate the boundary between labeled and unlabeled cells in the enamel organ and odontoblast layer at various times after a single injection of 3H-thymidine. This boundary, or leading edge of the front of labeling, was graphically illustrated through point-plotting reconstruction of the labial surface of the incisor. At one hour after the injection of 3H-thymidine the front of labeled ameloblasts was located within the presecretory zone related to early predentin secretion. This front formed a "C"-shaped curve stretching across the labial surface of the tooth from the lateral to the mesial cemento-enamel junction. The "C" was open anteriorly and the lateral arm extended almost twice as far incisally as the mesial arm. The edge of the front of labeled odontoblasts was positioned apical to and parallel with this "C"-shaped curve. The morphological appearance of all cells along each respective front was found to be similar. As the fronts of labeled ameloblasts and labeled odontoblasts moved forward with the erupting incisor, the cells along these fronts differentiated simultaneously and subsequently formed enamel and dentin. Throughout this movement the distance between fixed points along the leading edge of the front of labeled ameloblasts, and its positional relationship to the front of labeled odontoblasts, did not change appreciably. This indicated that cells of the tooth were being carried incisally at a uniform speed. It was concluded that renewal in the rat incisor consists of the generation by the bulbous part of the odontogenic organ of epithelial "U"-shaped cross-sectional segments which enclose a core of pulp. As this segment is transported towards the gingival margin, cellular differentiation and subsequent formation of hard tissue is seen to begin at the central labial side of the segment and to progress in a mesial and lateral direction towards the lingual side. In the process, the limits of the enamel organ at the mesial and lateral cemento-enamel junctions are established and the entire circumference of the segment is eventually enclosed by a rim of dentin.
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Smith CE, Warshawsky H. Cellular renewal in the enamel organ and the odontoblast layer of the rat incisor as followed by radioautography using 3H-thymidine. Anat Rec (Hoboken) 1975; 183:523-61. [PMID: 1200409 DOI: 10.1002/ar.1091830405] [Citation(s) in RCA: 143] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Renewal of the cell populations of the incisor was studied in 100 gm male rats injected with a single dose of 3H-thymidine and sacrificed at various times from one hour to 32 days after injection. Radioautographs showed that a cohort of labeled cells within the enamel organ, odontoblast layer, and pulp was carried passively with the erupting incisor from the apical end towards the gingival margin where the life cycle of these cells was terminated. Labeled cells in the upper and lower incisor, although traversing different absolute lengths, were found in approximately the same functional stage of their life cycle at similar times after the injection. Thus, by one and on-half days labeled ameloblasts began inner enamel secretion and, by eight days (upper) or nine days (lower), complement outer enamel secretion. By 32 days labeled ameloblasts had traversed the entire enamel maturation zone and were located at the gingival margin. Labeled odontoblasts followed closely the movement of labeled ameloblasts. The mean rate of ameloblast migration was 567 mum/day on the upper incisor and 651 mim/day on the lower. For the odontoblasts this rate was 55 mum/day (upper) and 631 mum/day (lower). Finally, it was found that as the rat age, the duration of the life cycle for epithelial and pulp cell populations of the incisor increased because of growth within the lonitudinal axis of the tooth. It was concluded that the apical end of the incisor literally "grows backward" in the bony socket, and hence, the duration of the life cycle becomes greater simply because it takes cells longer to physically reach the gingival margin.
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Abstract
Three of the 4 groups of 3 Wistar rats each were given 40 mg, 80 mg and 120 mg cyclophosphamide/kg respectively by single intraperitoneal injections. The fourth group was given 2 ml of normal saline as control. One animal from each group was killed after 1, 4 and 8 days. The incisor teeth of all experimental animals showed evidence of cytotoxic injury, which appeared to be more severe with increasing dosage, to the undifferentiated mesenchymal cells in the proliferating zone of the pulp close to the basal odontogenic epithelium, cessation of root growth and relative acellularity of the basal area of the pulp. Evidence of cytotoxicity to the odontogenic epithelium was seen only in the groups given 80 mg/kg and 120 mg/kg. Resolution of the cytotoxic injury and re-establishment of normal basal odontogenesis were seen in the 40 mg dose group by the eighth day but appeared to be slower with increasing dosage. It would seem that of the rapidly proliferating epithelial and mesenchymal odontogenic cells in the basal area of the rat incisor those in the mesenchyme may be most susceptible to the cytotoxicity of cyclophosphamide. The odontogenic epithelium may be resistant to the cytotoxicity of 40 mg cyclophosphamide/kg. The results may be of significance in the investigation of the mechanism of cytotoxicity of this cancer chemotherapeutic agent.
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Smith CE, Warshawsky H. Histological and three dimensional organization of the odontogenic organ in the lower incisor of 100 gram rats. THE AMERICAN JOURNAL OF ANATOMY 1975; 142:403-29. [PMID: 1155352 DOI: 10.1002/aja.1001420402] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A three dimensional reconstruction of the epithelial tissue at the apical end of the lower rat incisor was made from serial 1 mum thick cross sections. This tissue formed an elongated structure, called the odontogenic organ, which was composed of a bulbous and a "U"-shaped part. Both parts were joined to one another at the posterior aspect of the apical foramen. The bulbous part of the odontogenic organ was situated at the lingual side of the "U"-shaped part and protruded anteriorly over the pulp. It was formed by cells of the outer dental epithelium and stellate reticulum whose organization suggested that the bulbous part was important in the production of cells for renewal of all the epithelia of the incisor. The "U"-shaped part of the odontogenic organ was apparently derived from the bulbous part and delineated the pulp by forming the lateral, mesial and labial sidewalls around the apical foramen. It was composed of all the epithelial cell types recognizable as precursors to (a) cells of the enamel organ which form the enamel, and (b) Hertwig's epithelial root sheath, a part of the odontogenic organ which induces the formation of dentin on the lingual aspect of the incisor.
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Mantell PA. The circadian rhythm of mitotic activity in the incisor pulp and the cornea of Rattus norvegicus. Arch Oral Biol 1973; 18:403-7. [PMID: 4515968 DOI: 10.1016/0003-9969(73)90164-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Michaeli Y, Greulich RC. A three dimensional representation of the odontogenic epithelium of the rat incisor. Anat Rec (Hoboken) 1972; 174:389-97. [PMID: 5082963 DOI: 10.1002/ar.1091740310] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Berkovitz BK. The effect of demecolcine and of triethanomelamine on the unimpeded eruption rate of normal and root resected incisor teeth in rats. Arch Oral Biol 1972; 17:937-47. [PMID: 4504658 DOI: 10.1016/0003-9969(72)90117-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Moe H, Jessen H. Phagocytosis and elimination of amelocyte debris by stratum intermedium cells in the trasitional zone of the enamel organ of the rat incisor. ZEITSCHRIFT FUR ZELLFORSCHUNG UND MIKROSKOPISCHE ANATOMIE (VIENNA, AUSTRIA : 1948) 1972; 131:63-75. [PMID: 5073642 DOI: 10.1007/bf00307201] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Zajicek G, Bar-Lev M. Kinetics of the inner enamel epithelium in the adult rat incisor. I. Experimental results. CELL AND TISSUE KINETICS 1971; 4:155-62. [PMID: 5128279 DOI: 10.1111/j.1365-2184.1971.tb01525.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Review of Dental Research. J Am Dent Assoc 1968. [DOI: 10.14219/jada.archive.1968.0208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Chiba M, Nakagawa K, Mimura T. DNA synthesis and cell division cycle at the base of the maxillary incisor tooth of the young rat. Arch Oral Biol 1967; 12:865-76. [PMID: 5231458 DOI: 10.1016/0003-9969(67)90109-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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