1. Division of Biliopancreas, Department of Internal Medicine, Wonkwang University Hospital, Wonkwang University Medical School, Iksan, Korea
2. Institute of Wonkwang Medical Science, Iksan, Korea
3. Department of Internal Medicine, Jeonbuk National University Hospital, Jeonju, Korea
4. Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju, Korea