CJCP     2011 13 (10):  776-779    ISSN: 1008-8830  CN: 43-1301/R Measurement of umbilical activin A level in preterm infants ZHONG Ying, LI Juan, WEI Ke-Lun Department of Neonatology, Shengjing Hospital of China Medical University, Shenyang 110004, China. lijuan8@yahoo.com.cn Received: null  Revised: null  Online: null Supporting info