1. Veterinary Teaching Hospital, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido 060–0818, Japan
2. Laboratory of Veterinary Internal Medicine, Graduate School of Veterinary Medicine, Hokkaido University, Hokkaido 060–0818, Japan
3. Department of Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, Serdang 43400, Malaysia
4. Veterinary Small Animal Internal Medicine, Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Iwate 020–8550, Japan