1. Laboratory of Basic Veterinary Science, the United Graduate School of Veterinary Science, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753–8515, Japan
2. Laboratory of Veterinary Anatomy, Joint Faculty of Veterinary Medicine, Yamaguchi University, Yamaguchi 753–8515, Japan
3. Laboratory of Veterinary Biochemistry and Molecular Biology, Department of Veterinary Sciences, Faculty of Agriculture, University of Miyazaki, Miyazaki, 889–2192, Japan
4. Laboratory of Laboratory Animal Science, Division of Veterinary Science, Graduate School of Life and Environmental Science, Osaka Prefecture University, Osaka 598–8531, Japan