[1] Otsuka Pharmaceut Co Ltd, Otsuka GEN Res Inst, Tokushima 7710192, Japan
[2] Univ Tokyo, Fac Med, Dept Gastroenterol, Bunkyo Ku, Tokyo 1138655, Japan
[3] Japan Sci & Technol Corp, CREST, Bunkyo Ku, Tokyo 1138341, Japan
[4] Tokyo Metropolitan Inst Med Sci, Tokyo 113, Japan