1. Department of General Surgery, Guizhou Provincial People's Hospital, Guiyang Medical University, Guiyang, Guizhou 550002, P.R. China
2. Graduate School of Surgery, Zunyi Medical University, Zunyi, Guizhou 563003, P.R. China
3. Department of Pharmacy, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan 611130, P.R. China