1. The United Graduate School of Veterinary Science, Yamaguchi University, 1677-1, Yoshida, Yamaguchi 753-8511, Japan
2. Joint Department of Veterinary Medicine, Tottori University, Minami 4-101, Koyama-Cho, Tottori 680-8553, Japan
3. Global Application Development Center Analytical & Measuring Instruments Division, Shimadzu Corporation, 1 Nishinokyo, Kuwahara-cho, Nakagyo-ku, Kyoto 604-8511, Japan