1 Division of Pediatrics, Department of Homeostatic Regulation and Development, Faculty of Medicine, Graduate School of Medical and Dental Science, Niigata University, Niigata City, Niigata, Japan.
2 Division of Pediatrics, Department of Homeostatic Regulation and Development, Faculty of Medicine, Graduate School of Medical and Dental Science, Niigata University, Niigata City, Niigata, Japan nagasaki@med.niigata-u.ac.jp.