1. Department of Internal Medicine, Kawasaki Medical School, Okayama, Japan
2. Department of Medicine, Baylor College of Medicine, Houston, TX, USA
3. GI Division, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
4. Department of Medicine, Michael E. DeBakey Veterans Affairs Medical Center and Baylor College of Medicine, Houston, TX 77030, USA