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  • 1
    Electronic Resource
    Electronic Resource
    Variation in collagen expression by cloned periodontal ligament cells (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 18 (1983), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Isolation in vitro of clonal populations of fibroblasts from enzyme digested porcine periodontal ligament (PL) has made possible the comparison of collagen synthesis between single colonies of cells. Despite low cloning efficiencies, two independent PL isolations yielded enough clones for detailed analysis. In the first group of clones, the amount of 14C-labelled collagen synthesized compared to the total protein synthesis varied from 32% to 47%, whereas the values from the second group, with one exception, ranged from 55% to 70%. Each clone synthesized types I, III, and V collagens. However, the relative amounts of these collagens varied from one clone to another in both groups: i. e. the type III collagen synthesis ranged from 10% to 32% of the total collagen in most clones. A single clonal population produced type I collagen almost exclusively and in another collagen synthesis was barely detectable. These results indicate that primary cultures of PL cells contain a heterogenous mixture of cells that not only synthesize different levels of collagen but produce distinctly different ratios of collagen types. These findings further suggest that the PL contains distinct populations of fibroblast-like cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1983.tb00358.x
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  • 2
    Electronic Resource
    Electronic Resource
    Synthesis of collagenolytic enzymes and their inhibitors by gingival tissue in vitro (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 16 (1981), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Porcine gingival explants maintained in culture produced collagenase and non-specific gelatinase. These enzymes were detected in both latent and active forms in explant culture medium. The latent enzymes could be activated by limited proteolysis with trypsin or by treatment with organomercurials (4-hydroxy mercuribenzoate, PCMB and 4-aminophenylmercuric acetate, APMA). The explants also produced protein capable of inhibiting the collagenase and non-specific gelatinase activities. Treatment of inhibitor with trypsin or organomercurials under latent enzyme activation conditions blocked the inhibitory activity against both enzymes suggesting that the latent enzymes are enzyme-inhibitor complexes. A specific gelatinase was also detected in the culture medium in an active form which was not inhibited by other macromolecules in the medium. The addition of endotoxin (30 μg/ml) to the gingival explant medium increased the synthesis of the collagenase and non-specific gelatinase activities but had no apparent effect on the production of the inhibitor activity nor the specific gelatinase activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1981.tb01002.x
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  • 3
    Electronic Resource
    Electronic Resource
    A highly sensitive and specific assay for vertebrate collagenase (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 16 (1981), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: A highly sensitive and specific assay for vertebrate collagenase has been developed using a [14C]-labeled collagen substrate and a combination of SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) and fluorography to identify and quantitate the digestion products. The assay was sufficiently sensitive to permit the detection and quantitation of collagenase activity in 0.1 μl of gingival sulcal fluid, and in samples of cell culture medium without prior concentration. The assay has also been used to detect the presence of inhibitors of collagenolytic enzymes in various cell culture fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1981.tb00993.x
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  • 4
    Electronic Resource
    Electronic Resource
    Evidence of a direct relationship between neutrophil collagenase activity and periodontal tissue destruction in vivo: role of active enzyme in human periodontitis (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 30 (1995), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To assess the temporal relationship between periodontal tissue destruction and the activity of collagenase, exudate from inflamed periodontal tissues was collected and latent and active collagenase activities were measured by a functional assay in a longitudinal cohort study. Comparisons were made between human subjects with either: 1) inflammation with a previous history of progressive loss of connective tissue and bone support (n=14); 2) inflammation and previous history of bone loss but now clinically stable (n=27); or 3) inflammation and no loss of bone support (n=17). Experiments using specific enzyme inhibitors, blocking antibodies and SDS-PAGE fluorograph to identify the pattern of collagen substrate degradation demonstrated that the collagenase activity was derived from neutrophils and not from bacteria or other host cells. Active collagenase activity pooled from 6 sites per subject was respectively 5 and 6-fold higher in the group with progressive loss of connective tissue compared to the groups with either inflamed tissues alone or with inflammation and previous bone loss. In contrast, latent collagenase was increased up to 2 fold higher in the group with inflammation but no bone loss compared to the group with progressive lesions. Moreover, the ratio of active to total collagenase activity was 50% higher in the group with progressive lesions. Although in all subjects successive measurements of site-specific active collagenase 1 month apart demonstrated wide variation (r〈0.50), only in sites with progressive periodontal destruction was there significant increase of active collagenase with time (1.28×l0−4 collagenase units per day). There were also sharp elevations in active enzyme level at the time of detection of loss of connective tissue attachment in specific sites of 8 subjects. At the time of detection of connective tissue attachment loss, there was an overall 40% increase of pooled active collagenase activity in all subjects with progressive loss of connective tissue compared to pre-breakdown sampling times. These data provide strong in vivo evidence for a direct role of active neutrophil collagenase in the pathological destruction of periodontal connective tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1995.tb01249.x
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  • 5
    Electronic Resource
    Electronic Resource
    Con A stimulation of collagenase synthesis by human gingival fibroblasts (1983)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 18 (1983), S. 0 
    Details
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Presence of 10–1000 μg/ml of Con A in cultures of human gingival fibroblasts promoted the synthesis and secretion of collagenase. Incubation with Con A for a minimum of 6 hours was required for the effect which could be inhibited over this time period by the addition of α-methyl mannoside. In the continuous presence of Con A, a latent period of at least 8 hours was required before the stimulating effect was observed. Con A also stimulated the synthesis of a number of other unidentified proteins secreted into the medium. Of other lectins tested, phytohemagglutinin produced a moderate stimulation of collagenase production, but only a small effect was observed with pokeweed mitogen and wheat germ agglutinin. The enzyme, which was detected almost entirely in a latent form, was shown to be a true collagenase through the production of typical 3/4- and 1/4- fragments from a collagen substrate at neutral pH and the inhibition of activity by sulfhydryl compounds and metal chelators.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0765.1983.tb00347.x
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  • 6
    Electronic Resource
    Electronic Resource
    Collagenase synthesis by osteoblast-like cells (1984)
    Springer
    Calcified tissue international 36 (1984), S. 722-724 
    Details
    ISSN: 1432-0827
    Keywords: Bone resorption ; Osteoblasts ; Collagenase ; Collagenase inhibitor ; Concanavalin A
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Cultures of osteoblast-like cells from a rat sarcoma and osteoblast-enriched populations of rat calvarial cells synthesize and secrete a true collagenase and collagenase inhibitor. The enzyme, which is produced in a latent form, appears to be similar to the enzyme produced by fibroblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02405395
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of ascorbic acid on protein synthesis and collagen hydroxylation in continuous flow organ cultures of adult mouse periodontal tissues (1982)
    Springer
    Calcified tissue international 34 (1982), S. 408-415 
    Details
    ISSN: 1432-0827
    Keywords: Alveolar bone ; Periodontal ligament ; Hydroxyproline ; Collagen, types I, III, and V
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary A continuous flow organ culture system (CFCS) was used to determine the effect of ascorbic acid on the synthesis of collagen and noncollagenous protein by bone of the alveolar process and periodontal ligament in organ cultures of adult mouse periodontium. For the last 24 h of 2 day cultures, 5 µCi/ml3H-proline was added to the medium. Highly purified collagenase was used to separate the collagenous and noncollagenous proteins and the incorporation of isotope into each fraction measured. Collagen synthesized in the presence of less than 10 µg/ml ascorbic acid was found to be highly under-hydroxylated (pro:hypro sp. acts. 2.3–3.1) in both tissues. When the ascorbic acid levels were between 25 and 100 µg/ml, the synthesis of collagenous proteins was selectively stimulated and hydroxylation significantly improved (pro:hypro sp. acts 1.72–1.89). The effect of ascorbic acid was not related to tissue viability since tissues cultured initially in the absence of ascorbic acid were able to recover completely when compared to controls given ascorbic acid continuously. The proportion of radioactivity in collagen and noncollagenous protein, collagen hydroxylation, and percentage of collagen synthesized as type III (av. 23%) in bone of the alveolar process was similar to that found in vivo. However, in the periodontal ligament in vitro the proportion of noncollagenous protein synthesized was increased from 70% to 87% and the percentage of type III collagen increased from 14% to 26% compared to in vivo results.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02411276
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  • 8
    Electronic Resource
    Electronic Resource
    Synthesis of noncollagenous extracellular matrix proteins during development of mineralized nodules by rat periodontal ligament cells In vitro (1995)
    Springer
    Calcified tissue international 57 (1995), S. 52-59 
    Details
    ISSN: 1432-0827
    Keywords: Periodontal ligament ; Mineralized nodule ; ECM proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract To characterize the mineralized nodules produced by rat periodontal ligament (PDL) cells in vitro, we have studied the synthesis and distribution of mineralized tissue proteins at various stages of nodule formation. PDL cells were obtained from coagulum in the socket at 2 days after tooth extraction and cultured in Dulbecco's Modified Eagles Medium (DMEM) containing 10% fetal bovine serum and antibiotics. Confluent cells were grown in the presence of ascorbic acid (50 μg/ml), dexamethasone (5 μM), and β-glycerophosphate (10 mM) for 3 weeks. Four stages showing distinct morphological characteristics during development of mineralized nodules were identified. Protein synthesis and deposition of proteins into the matrix were studied during these stages by metabolic labeling with [35S]methionine for 24 hours. Large quantities of SPARC (secreted protein, acidic and rich in cysteine) were synthesized by confluent cells but decreased during the progress of mineralized nodule formation. Two forms of osteopontin (OPN) (67 kDa and 61 kDa) were synthesized in comparable quantities by confluent cells; OPN and bone sialoprotein (BSP) were induced by dexamethasone and represented the major proteins in the mineralized matrix. The 67 kDa form of OPN was the predominant species in the mineralized matrix. Both OPN and BSP were localized by immunogold electron microscopy on globular as well as fused electron-dense structures at sites of tissue mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298997
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