1. Department of Veterinary Internal Medicine, Graduate School of Agricultural and Life Sciences, the University of Tokyo, 1–1–1 Yayoi, Bunkyo-ku, Tokyo 113–8657, Japan
2. Japan Small Animal Medical Center, 2–27–4 Nakatomi-minami, Tokorozawa, Saitama 359–0003, Japan
3. Kariya Animal Hospital, 3–12–7 Kitasuna, Koto-ku, Tokyo 136–0073, Japan
4. 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