1. Animal Engineering Research Institute, Midorigahara, Tsukuba, Ibaraki, Japan.
2. Laboratory of Developmental Engineering, Meiji University School of Agriculture, Higashimita, Tama, Kawasaki, Kanagawa, Japan.
3. Division of Organ Transplantation, Department of Regenerative Medicine, Osaka University Graduate School of Medicine, Yamadaoka, Suita, Osaka, Japan.
4. STAFF Institute, Kamiyokoba, Tsukuba, Ibaraki, Japan.