1 Department of Physiology and Pathophysiology, The School of Basic Medical Sciences, Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, P.R. China.
2 Department of Urinary Surgery, General Hospital of Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, P.R. China.
3 Department of Prenatal Diagnosis, General Hospital of Ningxia Medical University, Yinchuan, Ningxia Hui Autonomous Region 750004, P.R. China.