1. Department of Surgery, Pusan National University Yangsan Hospital, Gyeongnam 50612, Korea
2. Biomedical Research Institute, Pusan Nat. Univ. Hospital, Pusan 602-739, Korea
3. Research Institute for Convergence of Biomedical Science and Technology, Pusan Nat. Univ. Yangsan Hospital, Gyeongnam 50612, Korea
4. Department of Biological Sciences, Andong National University, Andong 760-749, Republic of Korea