1. Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
2. Biomedical Research Institute, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
3. Department of Internal Medicine, Digestive Disease Center, Konkuk University Medical Center, Konkuk University School of Medicine, Seoul, Korea
4. Department of Physiology, University of Nevada School of Medicine, Reno, Nevada, USA
5. Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea