Comparison of methemoglobin levels in food protein-induced enterocolitis syndrome and other gastrointestinal diseases in neonates Eishi Makita; Sae Kuroda; Hiroaki Sato; Kae Itabashi; Atsuko Kawano; Misa Matsuura; Yohei Sugiyama; Daisuke Sugawara; Asami Maruyama; Ko Ichihashi;