title: Damage Effects on Bacille Calmette-Guérin by Low-Frequency, Low-Intensity Ultrasound: A Pilot Study.
abstract: OBJECTIVE
  To perform an in vitro experimental study of the possible damage effects on Bacille Calmette-Guérin (BCG) by low-frequency (42-kHz) ultrasound (US) irradiation at low spatially and temporally averaged intensities and different exposure times.
  
  
  METHODS
  A 2-mL BCG suspension was added to the wells of a 24-well cell culture plate. Then the samples were randomly divided into 4 groups, each group including 3 wells, with group 1 as a control group and groups 2, 3, and 4, as US treatment groups. The samples for groups 2, 3, and 4 were irradiated with US at 0.13 W/cm(2) for 5 minutes, 0.13 W/cm(2) for 15 minutes, and 1.53 W/cm(2) for 15 minutes, respectively. After irradiation, the temperature, ratio of damage, and structure of the bacteria were examined. The cavitation effect of the device was detected by the passive cavitation detection method.
  
  
  RESULTS
  After US irradiation at the different doses (intensity and exposure time), no significant temperature change was found in all sample suspensions. The ratio of bacterial damage tested by flow cytometry and the optical density of the suspensions as assayed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric method showed that the US-irradiated groups were significantly different from the control group. The BCG damage ratio reached 28% at the intensity of 1.53 W/cm(2). Transmission electron microscopic results showed that the bacterial structure of BCG could be destroyed by low-frequency, low-intensity US.
  
  
  CONCLUSIONS
  Low-frequency, low-intensity US can cause acute injury to BCG, and the degree of injury is closely correlated with the US dose applied.
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Hang
authors.initials: H
authors.lastname: Su
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Zhe
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Yuan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: He-Xun
authors.initials: HX
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Zheng
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.). duyonghong_e@126.com.
authors.forename: Yong-Hong
authors.initials: YH
authors.lastname: Du
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Junru
authors.initials: J
authors.lastname: Wu
authors.affiliation: State Key Laboratory of Ultrasound Engineering in Medicine, Cofounded by Chongqing and the Ministry of Science and Technology, Chongqing Key Laboratory of Biomedical Engineering, College of Biomedical Engineering, Chongqing Medical University, Chongqing, China (H.S., Z.L., Y.D., H.-Z.J., H.-M.Z, Y.-H.D., Z-.B.W.); and Department of Physics, University of Vermont, Burlington, Vermont USA (J.W.).
authors.forename: Zhi-Biao
authors.initials: ZB
authors.lastname: Wang
mesh_terms: D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D009163:Mycobacterium bovis / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure*; D010865:Pilot Projects; D011829:Radiation Dosage; D016896:Treatment Outcome; D014464:Ultrasonic Therapy / Q000379:methods*; D000069453:Ultrasonic Waves
keywords: Bacille Calmette-Guérin; damage effect; low-frequency ultrasound; low-intensity ultrasound; ultrasound doses