1 Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
2 Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. Electronic address: yamamura@pediatr.med.kyushu-u.ac.jp.
3 Department of Pediatric Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.