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Byline: K. Noguchi (1), K. Iwasaki (1), I. Ishikawa (1) Abstract: In the present study, the effect of prostaglandin E.sub.2 (PGE.sub.2) on intercellular adhesion molecule-1 (ICAM-1) expression in interferon-I3 (IFN-I3)-stimulated human gingival fibroblasts (HGF) was investigated. Addition of PGE.sub.2 to HGF inhibited ICAM-1 expression elicited by IFN-I3. As PGE.sub.2 elevated intercellular cyclic AMP (cAMP) levels in HGF in a dose-dependent fashion, the effect of dibutyryl cAMP and 8-bromo-cAMP, cAMP analogues, on IFN-I3-elicited ICAM-1 expression was examined. Both the agents downregulated ICAM-1 expression in IFN-I3-stimulated HGF. Next, we examined which subtype(s) of the four PGE.sub.2 receptor subtypes (EP.sub.1, EP.sub.2, EP.sub.3 and EP.sub.4) modulated the ICAM-1 expression elicited by IFN-I3, using subtype-specific agonists or antagonists. An EP.sub.2/EP.sub.4 agonist, 11-deoxy-PGE.sub.1, attenuated IFN-I3-elicited ICAM-1 expression in a concentration-dependent manner. A specific EP.sub.4 antagonist, AH-23848B, showed no effect on inhibition of IFN-I3-elicited ICAM-1 expression by PGE.sub.2 and 11-deoxy-PGE.sub.1. Butaprost, an EP.sub.2-selective agonist, mimicked inhibition of IFN-I3-elicited ICAM-1 expression by 11-deoxy-PGE.sub.1. An EP.sub.3 agonist, ONO-AP-324, was inert with respect to IFN-I3-elicited ICAM-1 expression. Sulprostone, an EP.sub.1/EP.sub.3 agonist, showed stimulatory effect on ICAM-1 expression elicited by IFN-I3. From these results, we suggest that PGE.sub.2 downregulates IFN-I3-induced ICAM-1 expression in HGF, primarily via EP.sub.2 receptors by cAMP-dependent signaling pathways. Author Affiliation: (1) Department of Periodontology, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University, 1--5--45, Yushima, Bunkyo-ku, Tokyo, 113--8549, Japan Article History: Registration Date: 30/09/2004

Byline: K. Noguchi (1), M. Shitashige (2), H. Watanabe (1), S. Murota (2), I. Ishikawa (1) Abstract: The purpose of the present study was to investigate the involvement of cyclooxygease-1 (COX-1) and cyclooxygenase-2 (COX-2) in prostaglandin (PG) production by human periodontal ligament (PDL) fibroblasts stimulated with a proinflammatory cytokine, inerleukin-1[beta] (IL-1[beta]), and to examine the effect of interleukin-4 (IL-4), a Th2 cytokine, and interferon-I3 (IFN-I3), a Th1 cytokine, on PG production by the cells. IL-1[beta]-stimulated PDL fibroblasts produced prostaglandin E.sub.2 (PGE.sub.2) in a time-dependent manner. Indomethacin, a non-selective COX-1/COX-2 inhibitor, and NS-398, a selective COX-2 inhibitor, completely inhibited PGE.sub.2 production by IL-1[beta]-stimulated cells. Northern blot analysis showed that COX-2 mRNA was detected in IL-1[beta]-stimulated PDL cells, although not detected in unstimulated cells, while expression of COX-1 mRNA was in the same extent in both the cells. Dexamethasone inhibited COX-2 mRNA expression, COX activity and PGE.sub.2 production in IL-1[beta]-stimulated cells. IL-4 and IFN-I3 suppressed PGE.sub.2 production by IL-1[beta]-stimulated PDL fibroblasts, but COX activity enhanced by IL-1[beta] treatment was significantly inhibited by IL-4, not by IFN-I3. Northern blot analysis showed that IL-4 depressed COX-2 mRNA expression with no effect on COX-1 mRNA expression. On the other hand, IFN-I3 had no effect on expression of COX-1 and -2 mRNA. These data suggest that COX-2 is primarily responsible for PGE.sub.2 production by IL-1[beta]-stimulated human PDL fibroblasts and that IL-4 inhibited PGE.sub.2 production by IL-1[beta]-stimulated PDL fibroblasts through down-regulation of COX-2 expression, while IFN-I3 suppressed the PGE.sub.2 production with no effect on COX-2 expression. Author Affiliation: (1) Department of Periodontology, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University, 1--5--45, Yushima, Bunkyo-ku, Tokyo, 113--8549, Japan (2) Department of Physiological Chemistry, Graduate School, Faculty of Dentistry, Tokyo Medical and Dental University, 1--5--45, Yushima, Bunkyo-ku, Tokyo, 113--8549, Japan Article History: Registration Date: 14/10/2004

Current-voltage curve measurements were conducted for a dip-coated Bi-2212 tape wire at several temperatures under a magnetic field parallel to the c-axis. Results show that normalizing causes the current voltage curves to be approximately scaled on two master curves. Furthermore, the measured dynamic critical index of 3 was found to be too small. Results were validated through comparisons with a theoretical analysis using the flux creep-flow model.