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The Porphyromonas gingivalis ATCC 53977 prtC gene, which codes for collagenase, was isolated and its purified product was characterized. The results showed that prtC collagenase hydrolyzes type I collagen, but does not exhibit structural similarity to homologous eukaryotic collagenases. The prtC gene contained two open reading frames differing by only three amino acids. Sequence analysis predicted a dimeric protein of 70-kDa. These results demonstrate that the P. gingivalis collagenase is a novel enzyme. In addition, the results also indicate the presence of two distinct collagenases in this strain.

Purpose: Titanium (Ti) is frequently used in dental implants because of its excellent corrosion resistance, mechanical properties, and biocompatibility. However, Ti ions may be slowly released as a result of corrosion, contributing to peri-implantitis, a major cause of dental implant failure. This study examined the influence of Ti ions on cytokine levels in murine splenocytes, an immunocompetent cell type, stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS) and the influence of Ti ions on splenocyte viability. Materials and Methods: Splenocytes were prepared from 5- to 10-week-old male C57BL/6 mice and BALB/c mice. Cytokine levels in culture supernatants from murine splenocytes stimulated with A actinomycetemcomitans LPS were determined with enzyme-linked immunosorbent assay. A tetrazolium salt assay was carried out to evaluate the cytotoxicity of Ti ions against murine splenocytes. Results: The present study demonstrated that Ti ions influence cytokine levels in LPS-stimulated splenocytes. Significantly higher values (P < .05) were observed for interleukins 1β, 6, and 10; interferon-γ; tumor necrosis factor alpha; and granulocyte macrophage colony-stimulating factor in the culture supernatants of LPS-stimulated splenocytes of both mouse strains in the presence of Ti ions, as compared to the absence of Ti ions. Tetrazolium salt assay confirmed that the Ti ions used in this study did not affect the viability of murine splenocytes. Conclusion: This study suggests that Ti ions enhanced cytokine production induced by periodontopathic bacterial LPS. [ABSTRACT FROM AUTHOR]

Indoxyl sulfate (IS) is related to the development of cardiovascular disease and total mortality in dialysis patients. High‐performance liquid chromatography (HPLC) is the conventional measurement approach. However, the HPLC method is difficult to perform in real time. Recently, the IS Assay Kit "NIPRO", which enables the measuring of total IS by the enzyme method, was developed. This new reagent allows the easy and quick measurement of many samples using the automatic biochemical analyzer. Moreover, it was reported that it demonstrated satisfactory analytical performance. If this enzyme method is useful for measuring IS in hemodialysis, we can expect that the mechanism in which the IS effects adversely on a body as uremic toxins will be clarified. However, the enzyme method is more easily influenced by other coexisting substances. In this study, we have assessed on how the uremic toxins and anticoagulation effect on this new reagent and evaluate whether it can be put into practice effectively for hemodialysis patients. For the enzyme method, accuracy, simultaneous repeatability, linearity, limit of detection, influence of coexisting materials, and correlation with the HPLC method were examined. Accuracy and simultaneous repeatability were satisfactory, and linearity was good. The limit of detection was acceptable, and there was no influence of coexisting materials. With regard to the correlation, the regression equation was y = 0.947X + 7.987 and the correlation coefficient (r) was 0.972. This new reagent showed sufficient fundamental performance and had a good correlation with the conventional HPLC method for assessing the plasma of dialysis patients. [ABSTRACT FROM AUTHOR]