1. Department of Pediatrics, Yidu Central Hospital of Weifang, Weifang, Shandong 262500, P.R. China
2. Department of Neurosurgery Ward II, Yidu Central Hospital of Weifang, Weifang, Shandong 262500, P.R. China
3. Department of Hematology, Shengli Oilfield Central Hospital, Dongying, Shandong 257034, P.R. China