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  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 18 (1983), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Fibroblasts of the rat periodontal ligament were studied in situ by the freeze-fracture technique. Large surfaces of the protoplasmic and extracellular faces of the cell membrane as well as, the membranes of the RER, Golgi apparatus, and other cytoplasmic organelles were viewed at the ultrastructural level. Intramembrane particles representing membrane proteins were visualized, and their concentration in various membranes measured.Features of the fibroblast cell surface appearing as rough patches were interpreted to represent areas of possible cell-to-matrix interaction. The use of the freeze-fracture technique in further studies of PDL fibroblast-matrix contact is discussed.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 17 (1982), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The effects of colchicine administration on the ultrastructure aad function of periodontal ligament fibroblasts was studied in young mice as a further attempt to document the microtubule-dependent nature of collagen secretory granule translocation.Disruption of the normal appearance of the Golgi complex was an early response to colchicine administration. This change was visible at the light microscopic level. At the electron microscopic level it was observed that Golgi saccules were dispersed and that Golgi cisternae were shorter and reduced in number. Microtubules were absent. Dense granules accumulated in a juxtanuclear region of cytoplasm previously occupied by the normal Golgi complex. Lipid droplets and autophagosomes were increased in number. Intermediate filaments (10 nm diameter) formed perinuclear fascicles several hours after colchicine treatment.These results as well as the recently published report (Cho & Garant 1981d) support the concept that microtubules play an important role in the normal organization of the Golgi complex and in the translocation of secretory granules to the fibroblast cell surface.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 17 (1982), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Fibroblasts of the transseptal fiber region of the periodontal ligament contain well developed bundles of microfilaments or stress fibers. The stress fibers are made up of numerous parallel and closely packed cytoplasmic filaments approximately 6 nm wide. These intra-cellular stress fibers appear to be connected to and colinear with extracellular non-striated microfibrils. The junction occurs at a juxta-membrane dense patch called the fibronexus (Singer 1979).Similar associations of cytoplasmic microfilament bundles and the attachment protein fibronectin have been shown by other investigators to be necessary for cell attachment to substrata and oriented cell migration in fibroblasts cultured in vitro.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 14 (1979), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Multiple injections of 3H-proline over a period of ten days produced a series of radiolabelled appositional bands at sites of new bone formation. Appositional surfaces of periodontal alveolar bone not only contained parallel appositional bands but also a second series of bands oriented perpendicular to the appositional bands. The perpendicular bands were continuous with Sharpey's fibers of the adjacent periodontal ligament (PDL). Labelling over Sharpey's fibers frequently extended beyond the osteoblasts and into the PDL. This pattern of 3H-Proline labelling suggests that new Sharpey's fiber are secreted simultaneouly with new bone deposition. The shape and polarity of adjacent PDL fibroblasts suggests that they may migrate away from the bone surface as they engage in Sharpey's fiber formation.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 20 (1985), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: A dramatic increase in proliferation of endothelial, paravascular cells, and PDL fibroblasts occurs during orthodontic tooth movement. The development of mirror symmetry in newly divided fibroblast daughter cell pairs in the rat periodontal ligament was studied.Periodontal ligament fibroblasts loose their polarity and the normal organization of their organelles during cell division. Daughter cells, however, regain polarity and organization of their organelles to form mirror images of each other within 10 hours after cell division starts. Cellular polarity begins to appear with projection of a distal cell process at late telophase. Polarization is completed between late telophase and cytokinesis by shifting the RER and Golgi complex from the cleavage plane area to a juxtanuclear position facing the distal cell process. The majority of the newly divided fibroblasts formed mirror images in orientation and organization of organelles prior to cell migration. The distal cell process is the leading edge; i.e., the nuclear-Golgi axis points toward the direction of movement.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Copenhagen : Munksgaard International Publishers
    Periodontology 2000 24 (2000), S. 0 
    ISSN: 1600-0757
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 19 (1984), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Administration of Beta-aminoproprionitrile (B-APN) to young mice produced a characteristic lesion, the lathyritic body, in the middle region of the PDL. Within these lesions the fibroblasts aggregated to form cell clusters of 10 to 20 cells. The aggregated fibroblasts bordered cell-free regions of collagenous matrix. Individual fibroblasts maintained cytoplasmic polarity and provided a good model for studying collagen secretion from immobilized fibroblasts.Collagenous matrix appeared to be resorbed in the immediate vicinity of the clustered fibroblasts. 3H-proline radioautography indicated that labelled collagenous matrix was preferentially lost from the middle region of the PDL of both control and experimental mice. However, the decrease in collagen in the middle region was accentuated by B-APN treatment and the aggregation of fibroblasts in that zone.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 14 (1979), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The fibroblasts of the periodontal ligament and especially those of the transseptal ligament are characteristically elongated with their long axes parallel to the principal fiber bundles. Their cytoplasmic orgamelles are polarized suggesting that secretory products are released from one end of the cell. The nucleus occupies the anterior pole of the cell. Cytoplasmic processes or lobopodia, containing numerous cytoplasmic filaments, extend from the anterior pole of the cell. The Golgi complex is situated in a large area of the cell between the nucleus and the distal end of the cell. Granular endoplasmic reticulum, mitochondria and numerous small vesicles are dispersed throughout most part of the cell. Intracellular collagen, akthough present in many areas of the cell, appears to be most abundant in the distal parts of the cell. Administration of colchicine in vivo, blocked collagen secretion and dereased cell elongation and polartity.Results of and analysis of the orientation and polarization of the fibroblasts in the periodontal tissues appear to support the concept that these cells undergo active migration in vivo along existing substrata and that migration may be coupled to collagen secretion.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 21 (1986), S. 0 
    ISSN: 1600-0765
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The secretion of 3labeld glycoproteins from periodontal ligament fibroblasts was, studied by light and electron microseopic radioautography. At 5, 10. and 20 minutes after intravenous injection, 3H-fucose was concentrated in Golgi cisternae and saccules. By 35 minutes, the label was dispersed to the cell periphery and extracellular matrix. At 8 hours after injection, almost all of the radioactive label was associated with the cell surface or the adjacent extracellular matrix. Labeled glycoprotein was contained in collagen secretion granules and appeared to be relesasd simultaneousley with the collagen precursors The distribution of 3H-fucose labeled material was uniform across the periodontal ligament.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Calcified tissue international 50 (1992), S. 459-467 
    ISSN: 1432-0827
    Schlagwort(e): Periodontal ligament fibroblast ; Mineralized nodule ; Ultrastructure
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin , Physik
    Notizen: Summary The purposes of this study were to determine whether periodontal ligament (PDL) cells are capable of producing mineralized nodules in vitro and to analyze ultrastructural features of the nodules. Rat PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured at confluence in standard medium containing Dulbecco's Modified Eagle's Medium supplemented with 10% FBS and antibiotics. To test mineralized nodule formation, cells were further cultured for an additional 3 weeks in the standard medium containing (1) ascorbic acid (50 μg/ml) and sodium β-glycerophosphate (10 mM), (2) ascorbic acid, sodium β-glycerophosphate, and dexamethasone (5 μM), or (3) ascorbic acid alone. Cells were then fixed in 2.5% glutaraldehyde, postfixed in 1% OsO4, and prepared for light and electron microscopy. Threedimensional nodules containing mineralized matrices were formed only when the cells were cultured in the presence of ascorbic acid and dexamethasone. They were composed of multilayered fibroblasts (up to 13 layers), and highly organized collagen fibrils with 64 nm cross-banding patterns between the cell layers. The fibroblasts in the nodules exhibited an elongated shape with a high degree of cytoplasmic polarity throughout the nodule, and have the morphological features of PDL fibroblasts as seen in vivo. Mineral deposition with needle-like crystals was initiated on collagen fibrils located in intercellular spaces of the upper cell layers and became increasingly heavier towards the bottom half of the nodules. X-ray microanalysis and electron diffraction analysis confirmed that mineral deposition contained calcium and phosphate in the form of immature hydroxyapatite. These nodules contained neither osteoblasts nor osteocytes, and have their own morphological organization and characteristics which differ from those formed by bone cells in culture. Therefore, these data suggest that PDL cells are capable of forming mineralized tissue in vitro with the morphological characteristics different from bone mineralized nodules.
    Materialart: Digitale Medien
    Standort Signatur Einschränkungen Verfügbarkeit
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