1. Laboratory of Veterinary Surgery, Department of Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1–58 Rinku-Oraikita, Izumisano, Osaka 598–8531, Japan
2. Veterinary Medical Center, Department of Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1–58 Rinku-Oraikita, Izumisano, Osaka 598–8531, Japan
3. Laboratory of Veterinary Pathology, Department of Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1–58 Rinku-Oraikita, Izumisano, Osaka 598–8531, Japan
4. Department of Small Animal Internal Medicine, School of Veterinary Medicine, Kitasato University, 23–35–1 Higashi, Towada, Aomori 034–8628, Japan