1 Department of Gastroenterology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, People's Republic of China.
2 Department of Gastroenterology, Xiangya Hospital Central South University, Changsha, Hunan, People's Republic of China.
3 Department of Gastroenterology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, People's Republic of China. fanggenlu@csu.edu.cn.