1. Laboratory of Veterinary Internal Medicine, Department of Clinical Sciences, Faculty of Veterinary Medicine, Hokkaido University, Kita 18-jo Nishi 9-chome, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
2. Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Kita 18-jo Nishi 9-chome, Kita-ku, Sapporo, Hokkaido 060-0818, Japan
3. Veterinary Teaching Hospital, Faculty of Veterinary Medicine, Hokkaido University, Kita 19-jo Nishi 10-chome, Kita-ku, Sapporo, Hokkaido 060-0819, Japan