1. Department of Veterinary Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
2. Department of Neurology, Japan Animal Referral Medical Center, 2–5–8 Kuji, Takatsu-ku, Kawasaki-shi, Kanagawa 213–0032, Japan
3. Tamura Animal Clinic, 7–16 Saeki-ku, Hiroshima-shi, Hiroshima 731-5100, Japan
4. Department of Surgery II, School of Veterinary Medicine, Azabu University, 1–17–71 Fuchinobe, Chuo-ku, Sagamihara-shi, Kanagawa 229–8501, Japan