1. Department of Pathobiology; Nihon University School of Veterinary Medicine 1866; Kameino Fujisawa Kanagawa 252-8510 Japan
2. Research Laboratories, Animal Science Division; Dainippon Pharmaceutical; 103, Fushio Ikeda Osaka 563-001 1 Japan
3. Iburi Nosai Hokubu Veterinary Clinical Center; 423-133, Azatouasa, Hayakita Yafutsu Hokkaido 059-1433 Japan
4. Clinical Laboratory Center; University of Tokyo Hospital; 7-3-1, Hongo Bunkyo Tokyo 113-0033 Japan