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Naho Yamamoto,1 Saki Kasuga,1 Daijiro Kabata,2 Myu Ono,1 Sakura Ando,1 Taisuke Hashimoto,1 Shiori Fujikawa,1 Hiroko Fujitani,3 Ayumi Shintani,2 Takashi Hamazaki1 1Department of Pediatrics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan; 2Department of Medical Statistics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan; 3Fujitani Clinic, Osaka, JapanCorrespondence: Naho Yamamoto, Department of Pediatrics, Osaka Metropolitan University Graduate School of Medicine, Osaka, Japan, Tel +81-6-6645-3816, Fax +81-6-6636-8737, Email naho_yama@omu.ac.jpPurpose: Pteridines are metabolites of tetrahydrobiopterin (BH4), being coenzymes for nitric oxide synthase (NOS). No study has clarified the relationship among pteridines and NOS, fractional exhaled nitric oxide (FeNO) generated by pteridines, and reactive oxygen species. In this study, we administered arginine, a precursor of NO, and confirmed changes in the levels of pteridines, FeNO, and reactive oxygen species and their relationship to clarify the pathogenesis of airway inflammation in which oxidative stress is involved, such as bronchial asthma.Patients and Methods: This is a prospective, randomized open-label study. Children, aged 2 to 15 years, who were scheduled for growth hormone stimulation tests and were able to undergo a respiratory function test were recruited. They were randomly divided into two groups: arginine-administered and control groups. In the former, L-arginine hydrochloride was intravenously administered. After administration, the levels of diacron-reactive oxygen metabolites (d-ROMs), serum pteridines, serum amino acids, and fractional exhaled NO (FeNO) were measured.Results: We analyzed 15 children aged 4 to 14 years. In the arginine-administered group, there was an increase in the FeNO level and a decrease in the d-ROMs level, reaching a peak 30 min after administration, compared with the control group. In addition, there was a decrease in the serum biopterin level and an increase in the d-ROMs level, reaching peak 60 min after administration.Conclusion: The administration of L-arginine increased the NO level and decreased the d-ROMs level. Due to this, biopterin may be consumed and decreased, leading to an increase in the d-ROMs level. As a reduction in reactive oxygen species leads to the relief of inflammation, arginine and biopterin may be useful for inhibiting inflammation.Keywords: asthma, biomarker, biopterin, child, FeNO, d-ROMs

Abstract Background: It was shown that a traditional Chinese medicine, Hochu - ekki - to (HET), had adjuvant effects in influenze vaccination in an animal experiment. This, however, could not [...]