title: Free radical formation induced by ultrasound and its effects on strand breaks in DNA of cultured FM3A cells.
abstract: Recent sonochemical studies have revealed that active oxygen species are formed by pyrolysis of water molecules due to high temperature cavitation bubbles. When aqueous solutions of DNA were sonicated, single-strand breaks and double-strand breaks of DNA were observed. Formation of double-strand breaks due to mechanical effects of cavitation and formation of single-strand breaks mostly due to free radicals were indicated. The sonochemically generated radicals from DNA constituents due to H atom and OH radical reactions, and pyrolysis processes, were identified by spin trapping with 3,5-dibromo-2,6-dideuterio-4-nitrosobenzene sulfonate. When suspensions of mouse mammary carcinoma FM3A cells and aqueous solutions of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were exposed to 1 MHz ultrasound in the presence of Ar, a good correlation between DMPO-OH formation and the cell killing induced by ultrasound were observed. Although single-strand breaks of DNA in the cells were observed at the maximum intensity of DMPO-OH formation and cell killing, double-strand breaks were not. Free radical formation by ultrasound in aqueous solutions and its relation to DNA strand breaks in vitro and in vivo are discussed.
authors.affiliation: Department of Experimental Radiology and Health Physics, Fukui Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kondo
authors.forename: T
authors.initials: T
authors.lastname: Kodaira
authors.forename: E
authors.initials: E
authors.lastname: Kano
mesh_terms: D000818:Animals; D004247:DNA / Q000737:chemistry*; D004249:DNA Damage; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D005609:Free Radicals; D066298:In Vitro Techniques; D051379:Mice; D013113:Spin Labels; D014407:Tumor Cells, Cultured; D014465:Ultrasonics
chemical_list: D005609:Free Radicals; D013113:Spin Labels; D004247:DNA