1. Laboratory of Veterinary Internal Medicine, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
2. Veterinary Teaching Hospital, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido 060-0818, Japan
3. Organization for Promotion of Tenure Track, University of Miyazaki, Miyazaki 889-2192, Japan
4. Department of Veterinary Medicine, Azabu University, Kanagawa 252-5201, Japan