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Biomedical subjects

Shunsei Hirohata

Publications and source records attributed to Shunsei Hirohata.

23 records · Page 2Linked to original sources

Efficacy of rebamipide as adjunctive therapy in the treatment of recurrent oral aphthous ulcers in patients with Behçet's disease: a randomised, double-blind, placebo-controlled study.

BACKGROUND: Behçet's disease (BD) is a recurrent inflammatory disease involving chronic recurrent oral aphthous ulcers (aphthae), uveitis, skin lesions and genital ulcers. We prospectively investigated the efficacy of rebamipide, a gastroprotective drug, against oral aphthous ulcers in BD patients. METHODS: In a multicentre, double-blind, placebo-controlled study, 35 patients with BD, having as the main symptom oral aphthosis, were randomised to receive rebamipide 300 mg/day or placebo for 12 to 24 weeks between August 1994 and December 1996. Oral aphthosis must have occurred within 4 weeks prior to enrolment and must have been visible for at least 7 days during that time. Oral aphthae count and pain scores were recorded daily in a diary by the patients themselves. Monthly aphthae count and pain scores were defined as the sum of aphthae count and pain scores for a month, respectively. Investigators rated the global improvement in aphthae count and pain using a 6-point scale. The rate of change in monthly aphthae count and pain scores in the first 3 and last 3 months of treatment were assessed in patients with more severe symptoms whose aphthae count and pain score were >28 at baseline (trial entry). RESULTS: The rate of moderate or marked improvement in aphthae count and pain was 36% (5 of 14 subjects) in the placebo group and 65% (11 of 17 subjects) in the rebamipide group. During months 2 to 6 of treatment, aphthae count tended to increase and reached a peak at month 4 in the placebo group but decreased in the rebamipide group. Pain score decreased to the same extent in both groups for the first 3 months of treatment; however, in the fourth to sixth months of treatment, the pain score tended to increase in the placebo group but decreased in the rebamipide group. In patients with a monthly aphthae pain score >28 at baseline, pain and count scores decreased throughout the 6 months of rebamipide treatment but increased during the last 3 months of treatment in the placebo group (p < 0.01 for the between-group comparisons). CONCLUSIONS: Rebamipide is well tolerated and improves the aphthae count and pain score in BD patients. It may therefore be useful in the treatment and prevention of frequently recurrent oral aphthous ulcers (not restricted to BD). Administration of rebamipide is not cumbersome, and it does not cause any discomfort, which corticosteroid ointments for example may do; furthermore, there are no specific adverse drug reactions. Rebamipide is therefore recommended as a long-term treatment for recurrent oral aphthous ulcers.

Adult↗

Regulation of human B cell function by sulfasalazine and its metabolites.

Although sulfasalazine is a well-known disease-modifying antirheumatic drug (DMARD), the mechanisms of its action remain unclear. Indeed, it remains uncertain whether sulfasalazine itself or one of its metabolites is responsible for the antirheumatic effects of sulfasalazine. Since one of the characteristic features of rheumatoid arthritis (RA) is chronic stimulation of B cells, we compared the effects of sulfasalazine and its metabolites on the in vitro function of human B cells. Ig production was induced from highly purified B cells from healthy donors by stimulation with Staphylococcus aureus Cowan I (SA) plus IL-2. Sulfasalazine suppressed the production of IgM and IgG at its pharmacologically attainable concentrations (1-10 microg/ml). Of the metabolites of sulfasalazine, sulfapyridine (SP) and 5-aminosalicylic acid (5-ASA), but not 4-acethyl SP, also significantly suppressed the production of IgM and IgG at their pharmacologically relevant concentrations. By contrast, any of sulfasalazine, SP, 5-ASA and 4-acethyl SP did not suppress the IFN-gamma production of immobilized anti-CD3 stimulated CD4+ T cells. These results indicate that sulfasalazine and its metabolites preferentially suppress the function of B cells, but not that of T cells, at their pharmacologically attainable concentrations. The data therefore suggest that not only sulfasalazine, but its metabolites, might contribute to the beneficial effects of sulfasalazine.

Animals↗

Bone marrow CD34+ progenitor cells stimulated with stem cell factor and GM-CSF have the capacity to activate IgD- B cells through direct cellular interaction.

Recent studies have suggested the involvement of bone marrow in the pathogenesis of rheumatoid arthritis (RA), in which proliferation of monocyte-lineage cells (MLC) as well as local B cell activation in the synovium play an important role. Here, we show that bone marrow-derived MLC have the capacity to activate human peripheral blood IgD- B cells. Bone marrow CD34+ cells from RA patients that had been stimulated with stem cell factor and GM-CSF for 3-4 weeks (>90% CD14+ HLA-DR+ cells, <0.5% CD19+ B cells, and <0.5% CD3+ T cells; MLC) induced the production of IgG much more effectively than that of IgM by highly purified B cells from healthy donors in the presence of IL-2 and IL-10. CD34+ cells from cord blood or from bone marrow of osteoarthritis patients also displayed the capacity to induce IgG production. The induction of IgG production by the bone marrow-derived MLC was markedly decreased when they were separated from B cells by a membrane filter. The bone marrow-derived MLC interacted preferentially with IgD- B cells to induce IgG production. These results indicate that upon stimulation with stem cell factor and GM-CSF, CD34+ progenitor cells differentiate into MLC that activate preferentially IgD- B cells through direct cellular interactions to produce IgG. Therefore, the data suggest that the accelerated recruitment of MLC from the bone marrow to the synovium might play a role in the local B cell activation in RA.

Adult↗

[Efficacy of leflunomide].

Leflunomide(Arava) is a novel immunomodulatory drug, the primary action of which is inhibition of de-novo pyrimidine synthesis by selective inhibition of dihydro-orotate dehydrogenase. It has been shown that leflunomide is effective in treating active rheumatoid arthritis(RA) in a placebo-controlled phase II study. Subsequent multinational, randomized, controlled phase III clinical trials demonstrated that leflunomide is as effective and safe as methotrexate and sulfasalazine in treatment of RA. Frequently reported adverse effects included diarrhea, nausea and vomiting, skin rash, reversible alopecia, and transient lever enzyme elevations. However, accumulating concerns about its toxic effects, especially hepatotoxicity, have been raised recently. In addition, rheumatologists should be aware that leflunomide has a much longer half life than any other disease modifying antirheumatic drug.

Animals↗