title: Stable cavitation induces increased cytoplasmic calcium in L929 fibroblasts exposed to 1-MHz pulsed ultrasound.
abstract: An increase in cytoplasmic calcium (Ca(2+) increase) is a second messenger that is often observed under ultrasound irradiation. We hypothesize that cavitation is a physical mechanism that underlies the increase in Ca(2+) in these experiments. To control the presence of cavitation, the wave type was controlled in a sonication chamber. One wave type largely contained a traveling wave (wave type A) while the other wave type largely contained a standing wave (wave type B). Fast Fourier transform (FFT) analysis of a sound field produced by the wave types ascertained that stable cavitation was present only under wave type A ultrasound irradiation. Under the two controlled wave types, the increase in Ca(2+) in L929 fibroblasts was observed with fluorescence imaging. Under wave type A ultrasound irradiation, an increase in Ca(2+) was observed; however, no increase in Ca(2+) was observed under wave type B ultrasound irradiation. We conclude that stable cavitation is involved in the increase of Ca(2+) in cells subjected to pulsed ultrasound.
authors.affiliation: Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Tsukamoto
authors.forename: Satoru
authors.initials: S
authors.lastname: Higashiyama
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshida
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Katsuko S
authors.initials: KS
authors.lastname: Furukawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Ushida
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003600:Cytosol / Q000000981:diagnostic imaging* / Q000378:metabolism*; D004867:Equipment Design; D005347:Fibroblasts / Q000000981:diagnostic imaging* / Q000378:metabolism*; D051379:Mice; D013010:Sonication / Q000379:methods*; D014159:Transducers; D014463:Ultrasonography
chemical_list: D002118:Calcium