[1] Cincinnati Childrens Hosp, Div Neonatol, Med Ctr, Perinatal Inst, Cincinnati, OH 45229 USA
[2] Cincinnati Childrens Hosp, Med Ctr, Div Clin Pharmacol, Cincinnati, OH USA
[3] Univ Cincinnati, Coll Med, Dept Pediat, Cincinnati, OH USA
[4] Sichuan Univ, W China Univ Hosp 2, Div Neonatol, Chengdu 610064, Peoples R China
[5] Univ Arkansas Med Sci, Div Neurol, Little Rock, AR 72205 USA