Activation of latent human fibroblast-type and neutrophil interstitial procollagenases as well as degradation of native type I collagen by supraand subgingival dental plaque extracts, an 80-kDa trypsinlike protease from Porphyromas gingivalis (ATCC 33277), a 95-kDa chymotrypsinlike protease from Treponema denticola (ATCC 29522), and selected bacterial species commonly isolated in periodontitis was studied. The bacteria included were PrevotelUa intermedia (ATCC 25261), PrevoteUla buccae (ES 57), PrevoteUa oris (ATCC 33573), Porphyromonas endodontalis (ES 54b), Actinobacillus actinomycetemcomitans (ATCC 295222), Fusobacterium nukeatum (ATCC 10953), Mitsuokela dentalis (DSM 3688), and Streptococcus mitis (ATCC 15909). None of the bacteria activated latent procollagenases; however, both sub-and supragingival dental plaque extracts (neutral salt extraction) and proteases isolated from cell extracts from potentially periodontopathogenic bacteria P. gingivalis and T. denticola were found to activate latent human fibroblast-type and neutrophil interstitial procollagenases. The fibroblast-type interstitial collagenase was more efficiently activated by bacterial proteases than the neutrophil counterpart, which instead preferred nonproteolytic activation by the oxidative agent hypochlorous acid. The proteases were not able to convert collagenase tissue inhibitor of metalloproteinase (TIMP-1) complexes into active form or to change the ability of TIMP-1 to inhibit interstitial collagenase. None of the studied bacteria, proteases from P. gingivalis and T. denticola, or extracts of supraand subgingival dental plaque showed any significant collagenolytic activity. However, the proteases degraded native and denatured collagen fragments after cleavage by interstitial collagenase and gelatinase. Our results indicate that proteases from periodontopathogenic bacteria can act as direct proteolytic activators of human procollagenases and degrade collagen fragments. Thus, in concert with host enzymes the bacterial proteases may participate in periodontal tissue destruction.

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The concentrations of doxycycline and 4-de-dimethylaminotetracycline required to inhibit 50% of collagenase activity were found to be 15 to 30 ,uM for human neutrophil and gingival crevicular fluid collagenases. Fibroblast collagenase was relatively resistant to inhibition by tetracyclines; the 50% inhibitory concentrations of doxycycline and 4-de-dimethylaminotetracycline were 280 and 510 ,uM, respectively.Interstitial collagenases (EC 3.4.24.7) are considered to be key initiators of collagen degradation during the progression of inflammatory diseases such as rheumatoid arthritis, corneal ulceration, and periodontal diseases. Elevated tissue levels of collagenase have been detected in these inflammatory diseases characterized by excessive collagen degradation. Both the amount of the enzyme and its conversion to an active form, possibly mediated by the action of proteinases and/or reactive oxygen metabolites, are increased during inflammation. Although the cellular origin(s) of collagenases in these diseases remains unclear, resident fibroblasts and epithelial cells as well as infiltrating leukocytes (neutrophils and macrophages) are considered potential sources of the enzymes (1,4,14,(23)(24)(25). Fibroblast-type interstitial collagenase (matrix metalloproteinase 1 or MMP-1), which is also produced by epithelial cells and monocyte/macrophages, and neutrophil interstitial collagenase (MMP-8) are distinct gene products and differ in their immunologic characteristics and substrate specificities (7,12,24). In addition, the physiological inhibitors a2-macroglobulin and tissue inhibitor of metalloproteinases have been found to inhibit the fibroblast collagenase more efficiently than the neutrophil collagenase (3, 27).Recently, Golub et al. (9) discovered a new, nonantimicrobial property of tetracyclines-an ability to inhibit the activity of interstitial collagenases from a variety of cellular and tissue sources. This effect has been confirmed by other investigators (4, 15), Moreover, a chemical modification of the tetracycline molecule that eliminates its antimicrobial efficiency does not result in a loss of its ability to inhibit collagenase (10). The specificity of the effect was partially addressed in a study showing that the tumor cell-derived type IV collagenase/gelatinase (MMP-2) can also be inhibited by tetracyclines (29). However, the ability of these drugs to inhibit different types of interstitial collagenases ' has not yet been investigated. We report here the differential susceptibility of human neutrophil and fibroblast interstitial collagenases to inhibition by a commercial antimicrobial tetracycline, doxycycline (DOXY) and by a chemically modified nonantimicrobial tetracycline (4-de-dimethylaminotetracycline or CMT-1) (10). Furthermore, we addressed * Corresponding author. the cellular source of collagenase in the inflammatory exudate of the human periodontal pocket (also called the gingival crevicular fluid) by using tetracycline inhibition as a probe.4-Aminophenylmercuric acetate and phenylmethylsul...

The membranes surrounding seven loose cementless acetabular implants were shown to contain polyethylene particles, birefringent in polarised light. Three of these implants were made of titanium alloy and the membranes around these contained titanium particles as well. There was no metallosis around the four implants made of chromium-cobalt-steel alloy. Both titanium and polyethylene particles caused migration, adherence and phagocytosis of CD11b-positive, peroxidase-negative macrophages. There were no histological signs of activation of the specific immune response; neither interleukin-2 receptor-positive activated T cells nor PCA-1 plasmablasts/plasma cells were present in the tissues. In cases of simple loosening, resident mesenchymal fibroblast-like cells were active. In aggressive granulomatosis, there were many macrophages and multinucleated giant cells but little fibroblast reaction. The clinical relevance of the findings is that the use of cementless prostheses is not a guarantee against adverse tissue reactions.

The co-occurrence of CD and SS should be recognized because of its effects on dental and oral mucosal health. A lower salivary gland inflammatory focus score and higher salivary flow rate in CD + SS than in SS suggests that a gluten-free diet treatment may alleviate autoimmune inflammation.