1. School of Veterinary Medicine, Azabu University, Sagamihara, Kanagawa 252-5201, Japan
2. Department of Molecular Life Science, Tokai University School of Medicine, Isehara, Kanagawa 259-1193, Japan
3. Higashi-Hiroshima Veterinary Clinical Center, Higashi-Hiroshima, Hiroshima 739-2106, Japan