1. Division of Organ Transplantation, Department of Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
2. Meiji University International Institute for Bio-Resource Research, Kawasaki 214-8571, Japan
3. Laboratory of Developmental Engineering, Department of Life Sciences, School of Agriculture, Meiji University, Kawasaki 214-8571, Japan
4. Present address: Division of Organ Transplantation, Department of Surgery, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan