1. Department of Theriogenology and Biotechnology, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Korea.
2. School of Chemical and Biological Engineering, College of Engineering, Seoul National University, Seoul 151-742, Korea.
3. Transplantation Research Institute, Seoul National University, Seoul 110-744, Korea.
4. Department of Medicine, College of Medicine, Seoul National University, Seoul 110-744, Korea.
5. Transplantation Center, Seoul National University Hospital, Seoul 110-744, Korea.