1. Department of Galactophore, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R.�China
2. Department of Neurology, Gansu Provincial Hospital, Lanzhou, Gansu 730000, P.R.�China
3. Department of Gastroenterology, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R.�China
4. Department of General Surgery, The First Hospital of Lanzhou University, Lanzhou, Gansu 730000, P.R.�China