@article{oai:repo.qst.go.jp:00079152,
 author = {Yogo, Katsunori and Murayama, Chieko and Fujisawa, Yoshiki and Maeyama, Takuya and Hirayama, Ryoichi and Ogawa, Yukihiro and Ken-ichiro, Matsumoto and Nakanishi, Ikuo and Yasuda, Hiroshi and Ishiyama, Hiromichi and Hayakawa, Kazushige and Yogo, Katsunori and Murayama, Chieko and Fujisawa, Yoshiki and Maeyama, Takuya and Hirayama, Ryoichi and Ogawa, Yukihiro and Matsumoto, Kenichiro and Nakanishi, Ikuo and Yasuda, Hiroshi and Hayakawa, Kazushige},
 issue = {6},
 journal = {Radiation Research},
 month = {Mar},
 note = {D-methionine (D-Met), a dextrorotatory isoform of the amino acid L-methionine (L-Met), can prevent oral mucositis and salivary hypofunction in mice exposed to radiation. However, the mechanism of its radioprotection is unclear, especially with regard to the stereospecific functions of D-Met. Radiation is known to cause injury to normal tissue by triggering DNA damage in cells. Thus, this study investigated whether the chirality of D-/L-Met affects radiation-induced events at the DNA level. We selected plasmid DNA assays to examine this effect in vitro, as these assays are highly sensitive and allow easy detection of DNA damage. Samples of supercoiled pBR322 plasmid DNA mixed with D-Met, L-Met, or dimethylsulfoxide (DMSO) were prepared and irradiated with a Bragg peak beam of carbon ions (~290 MeV/u) with a 6 cm spread. DNA strand breaks were detected by the change in the form of the plasmid and were subsequently quantified by agarose gel electrophoresis. We found that D-Met yielded approximately equivalent protection from carbon-ion-induced DNA damage as DMSO. Thus, we propose that the protective functions of Met against plasmid DNA damage could be explained by the same mechanism as that for DMSO, namely, hydroxyl radical scavenging. This stereospecific radioprotective mechanism occurred at a level other than DNA level. There was no significant difference between the radioprotective effect of D-Met and L-Met on DNA.},
 pages = {513--519},
 title = {Potential mechanisms for Protective Effect of D-Methionine on Plasmid DNA Damage Induced by Therapeutic Carbon Ions},
 volume = {193},
 year = {2020}
}