Minocycline reduces gingival collagenolytic activity during diabetes. Preliminary observations and a proposed new mechanism of action

Extracellular matrices and polypeptide growth factors as mediators of functions of cells of the periodontium. A review

This is a review of the interactions between cells and their extracellular matrices and polypeptide growth factors. The review not only attempts to provide a basic understanding of the functions of extracellular matrices and polypeptide growth factors but, in addition, suggests the role these biological molecules may play in periodontal regeneration. It is conceivable that future periodontal therapy will include the treatment of a scaled root with biological response modifiers to predictably attain a true new connective tissue attachment.

Molecular cloning of human synovial cell collagenase and selection of a single gene from genomic DNA

We used a subclone of a rabbit genomic clone for collagenase that cross-hybridizes with human synovial cell messenger RNA (mRNA) to identify a human collagenase complementary DNA (cDNA) clone. The human cDNA clone is 2.1 kilobases (kb) and selects a mRNA transcript of approximately the same size from primary cultures of rheumatoid synovial cells that produce collagenase, but no mRNA is selected from control (nonproducing) synovial fibroblasts. Restriction enzyme analysis and DNA sequence data indicate that our cDNA clone is full length and that it is identical to that recently described for human skin fibroblast collagenase. The cDNA clone identified a single collagenase gene of approximately 17 kb from blots of human genomic DNA. The identity of human skin and synovial cell collagenase and the ubiquity of this enzyme and of its substrates, the interstitial collagens types I, II, and III, imply that common mechanisms controlling collagenolysis throughout the human body may be operative in both normal and disease states.

Systemic tetracycline hydrochloride as adjunctive therapy in the treatment of persistent epithelial defects

Recent evidence shows tetracyclines have anticollagenolytic activity that may be clinically effective in disease treatment. This led us to use systemic tetracycline (oral tetracycline hydrochloride 1 g daily divided into 4 doses) as adjunctive therapy in treating 18 patients with persistent corneal epithelial defects. Fourteen of 18 patients healed their defects; within 48 hours (9 patients) and within two weeks (the other 5 responding patients). Two patients showed no effect and two showed disease progression.

Advances in understanding cell interactions in tissue resorption. Relevance to the pathogenesis of periodontal diseases and a new hypothesis

Much of the connective tissue degradation that takes place in periodontal diseases is mediated by proteolytic enzymes. Previous studies have focused on the action of proteinases released by invading polymorphonuclear neutrophils and macrophages, and bacterial enzymes. In view of recent work establishing that resident connective tissue cells can be induced by cytokines to bring about the destruction of their own matrix, we propose a new hypothesis. In this we envisage that a critical step is the interaction of bacterial antigens with inflammatory cells, resulting in the production of a cytokine, interleukin-1. Our interpretation of in vitro evidence is that the loss of connective tissue attachment and bone matrix resorption in periodontal diseases is mediated by metalloproteinases such as collagenase and stromelysin released by cells of the periodontium. Such proteolytic destruction can be induced by interleukin-1, whose production may not be dependent on a specific microbial flora but may be triggered by a number of organisms. It is now clear that interleukin-1 has multiple actions on both immune and non-immune cells; these include the induction of lymphocyte differentiation and proliferation and the stimulation of bone and cartilage resorption, and prostaglandin and metalloproteinase synthesis by connective tissues. It seems likely that further knowledge about the production and function of this cytokine will have an increasing impact in many diseases that involve resorption, particularly since interleukin-1-like molecules can be produced by cell types other than monocytes/macrophages, including keratinocytes and fibroblasts.

Development of a biochemical profile for gingival crevicular fluid. Methodological considerations and evaluation of collagen-degrading and ground substance-degrading enzyme activity during experimental gingivitis

The potential application of gingival crevicular fluid (GCF) analysis to periodontal diagnosis has been examined for more than 25 years. Unfortunately, the information available has not provided the clinician with a more sensitive means of diagnosing periodontal disease or an effective means of monitoring periodontal therapy. A careful review of the literature on GCF, however, suggests that discrepancies occur in the method of GCF collection, the use of GCF for analysis from pooled or isolated crevicular locations, the method of analyzing the samples and the way in which the data is reported. Studies in our laboratory have suggested a technique for GCF analysis that collects GCF from individual crevices with a filter paper strip inserted for a standard time, determines the volume of GCF collected with a calibrated electronic meter and elutes the material into a larger volume of diluent. This approach allows for detection of site-to-site and patient-to-patient differences in GCF volume while providing sufficient samples to analyze GCF for multiple constituents. We have used this approach to evaluate GCF for vertebrate forms of the enzymes collagenase (latent and active forms), beta-glucuronidase and arylsulfatase during the development of experimental gingivitis in man. Interproximal and midradicular areas were studied. Our results indicate that during the 4 weeks of the gingivitis, the absolute amount of active collagenase in GCF increased 550% at the interproximal sites and 190% in the midradicular sites, and the per cent of active collagenase increased from 15 to 71% at the interproximal sites, and from 16 to 36% at the midradicular sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibiotic susceptibility of anaerobic bacteria from the human oral cavity

Anaerobic, agar-dilution, minimal inhibitory concentrations (MICs) of 18 antibiotics are given for the numerically important bacterial groups from the human oral cavity. Strains are divided into susceptibility categories using the guidelines for interpretation of MICs suggested by the National Committee for Clinical Laboratory Standards. These guidelines are based on data on antibiotic concentrations attainable in serum following various dosage regimens. MICs are also compared with attainable gingival fluid levels where these are known. The highest percentages of strains were susceptible to tetracycline, with 89% of the 139 strains tested susceptible to serum levels and 97% conditionally susceptible to attainable gingival fluid levels. Ninety-eight percent of strains were conditionally susceptible to attainable gingival fluid levels of minocycline, but many strains, including Actinobacillus actinomycetemcomitans, were only moderately susceptible to attainable serum levels of this tetracycline analogue. Carbenicillin was effective against most groups of organisms, with the important exception of A. actinomycetemcomitans, at serum levels attainable with oral formulations of carbenicillin. Only 2% of the total strains tested were resistant to penicillin, while 33% of strains were categorized as moderately susceptible. Clindamycin was active against many strains of Gram-negative bacteria but was not active against A. actinomycetemcomitans, some Bacteroides, Eikenella corrodens, or the anaerobic vibrios. Metronidazole was active against A. actinomycetemcomitans, all five groups of oral Bacteroides tested, and against Capnocytophaga species. Chloramphenicol was active against A. actinomycetemcomitans, but not against most of the other groups of oral organisms. Nearly all groups contained strains non-susceptible to serum levels attainable with the usual doses of erythromycin, spiramycin, vancomycin, kanamycin, neomycin, streptomycin, doxycycline, oxytetracycline, or chlortetracycline; several strains were resistant to maximum attainable serum levels of each of these antibiotics except doxycycline.

The application of a collagen stabilizer to the gingiva of the beagle dog. Effect on ligature-induced periodontal disease

The objective of this study was to determine the effect of crevicular application of a collagen stabilizer on ligature-induced periodontal disease in beagle dogs. Fourteen male and female dogs, 15 months of age, were studied. The mandibular first molars and third and fourth premolars were ligated for 6 months and moderate periodontitis resulted. Ligatures were removed for 2 months and then replaced for an additional 3 months to experimentally mimic the episodic changes seen in human periodontal disease. Following this phase, ligatures were removed and the animals were assigned to a placebo or treatment group. Medications were then applied intracrevicularly, three times a week over 5 months using an IMAX irrigator. Clinical indices measured were plaque index (PI), gingival index (GI), gingival crevicular fluid flow (GCF), attachment level (AL), pocket depth (PD) and standardized radiographic analysis of alveolar bone height. While overall changes in PI, GI and GCF were not significant, the results showed that alveolar bone regeneration was increased approximately twice as much in the treatment group as compared to the placebo group, PD improved by 20% vs. 12.5% (P less than 0.001) and AL improved by 8.8% vs. 4.5% (P less than 0.001). The data were also evaluated in terms of the response in more severe sites as compared to those less severe. The results of these evaluations showed the more severe sites to be significantly more responsive to treatment than the less severe sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Tetracyclines inhibit parathyroid hormone-induced bone resorption in organ culture

Several tetracyclines (minocycline, doxycycline, tetracycline), in levels approximating physiologic concentrations, were found to inhibit parathyroid hormone-induced bone resorption in organ culture; the specificity of this effect was demonstrated by comparison with other (non-tetracycline) types of antibiotics. The ability of tetracyclines to inhibit bone resorption is consistent with the recent proposal by Golub et al. that these antibiotics can inhibit mammalian collagenolytic enzymes by a mechanism unrelated to the drug's antibacterial efficacy, a property which could be therapeutically useful in diseases characterized by excessive collagen breakdown.