1. Division of Neonatology, Center for Maternal Fetal and Neonatal Medicine, National Hospital Organization Nishisaitama Chuo National Hospital, Tokorozawa-shi, Saitama-ken 359-1151, Japan
2. Division of Neonatology, Musashino Red Cross Hospital, Musashino-shi 180-8610, Japan
3. Shino-Test Corporation, 2-29-14 Oonodai Minami-ku, Sagamihara-shi 252-0331, Japan
4. Division of Pediatrics, Nagoya City West Medical Center, Nagoya-shi 462-8508, Japan