1. Renal Division, Department of Medicine, Peking University First Hospital, Peking University Institute of Nephrology, Beijing, China
2. Renal Pathology Center, Institute of Nephrology, Beijing, China
3. Renal Division, Department of Medicine, Kailuan General Hospital, Tangshan, China
4. Laboratory of Electron Microscopy, Pathological Center, Peking University First Hospital, Beijing, China