Bioacoustics Research Lab
University of Illinois at Urbana-Champaign | Department of Electrical and Computer Engineering | Department of Bioengineering
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William D. O'Brien, Jr. publications:

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Title In-vivo fetal ultrasound exposimetry.
Author Daft CMW, Siddiqi TA, Fitting DW, Meyer RA, O'Brien WD Jr.
Journal IEEE Trans UFFC
Volume
Year 1990
Abstract An instrument has been developed to measure the acoustic pressure field in vivo during an obstetric ultrasound examination. This provides for improved intensity values for exposure calculations, to assist in assessment of bioeffects. The ultrasonic field is sampled using a calibrated seven-element linear array hydrophone of poly(vinylidene difluoride) transducers, which is placed as close as possible to the ovary, embryo, or fetus using a vaginal approach. The RF signals from the hydrophone are digitized at 50 MHz, and the maximum amplitude waveform received in the examination is recorded. The output of the clinical B-scanner is calibrated by a measurement with the hydrophone in a water bath. From the hydrophone measurements, the in vivo ISPTA, ISPTP, and ISPPA are computed. Further analysis allows the frequency-dependent tissue attenuation to be assessed.


Title In-vivo measurements of ultrasound attenuation in normal or diseased liver.
Author Parker KJ, Asztely MS, Lerner RM, Schenk EA, Waag RC.
Journal Ultrasound Med Biol
Volume
Year 1988
Abstract Ultrasonic attenuation coefficients of liver have been derived from echoes received by a modified commercial B-scan imaging instrument. Values have been measured from selected regions within liver scans of 59 individuals, of which 15 cases were presumed normal (based on medical histories), and the remainder were involved with diffuse liver disease such as alcoholic cirrhosis, chemotherapy toxicity, chronic hepatitis, and liver metastases. Medical histories on most individuals include the results of serum liver function enzymes, conventional B-scan examinations, and exposure to drugs and alcohol. The results of CT abdominal scans (N = 13) and/or liver biopsy (N = 12) were also available. The results show that normal attenuation values for human liver are 0.054 +/- 0.009 Np/cm-MHz (0.47 dB/cm-MHz) with a frequency dependence of fn, where n = 1.05 +/- 0.25, in agreement with in vitro studies of mammalian liver. In diffuse liver disease, no relationship was found between the attenuation coefficient and the results of CT or conventional ultrasonic examination. A trend towards higher attenuation with increased fibrosis and fat, as graded from liver biopsies, was noted, but the results were generally not statistically significant. However, a significant correlation was found between high values of attenuation and abnormal liver function tests. High attenuation is also found with ingestion of alcohol, chemotherapeutic agents, and steroids, all of which may affect liver composition.


Title Inability of genetic systems of Bacillus subtilis to detect a mutagenic effect of low frequency ultrasound.
Author Combes RD.
Journal J Appl Bacteriol
Volume
Year 1975
Abstract Possible mutagenic effects of low frequency (20 kHz) ultrasound have been assessed with genetic systems of Bacillus Subtilis. Ultrasound was unable to cause a detectable increase in the spontaneous frequency of back-mutation irrespective of the degree of killing. Similar treatments were incapable of producing mutagenic lesions that could be detected by the system of transformation after in vitro treatment of DNA. Transforming activity and molecular weight could be reduced without a corresponding decline in linkage between two contiguous markers. It is concluded that mutagenic effects of ultrasound could not be detected using these genetic systems.


Title Inactivation of firefly luciferase and rat erythrocyte ATPase by ultrasound.
Author Matthews JC, Harder WL, Richardson WK, Fisher RJ, Al-Karmi AM, Crum LA, Dinno MA.
Journal Membr Biochem
Volume
Year 1993
Abstract Previous work in our laboratories has shown that, amongst other effects, irradiation of frog skin with low intensity ultrasound causes reductions in the chemical driving force of the short-circuit current. This indicated that either the Na/K dependent ATPase or ATP availability were being reduced. We measured the effect of ultrasound irradiation on ATP and NA/K-dependent ATPase from inverted erythrocyte ghosts and on firefly luciferin and luciferase activity. Our findings demonstrate that ultrasonic cavitation-induced sonochemical reactions were responsible for irreversible inactivation of luciferase and ATPase but had little or no effect on ATP and luciferin. We measured the levels of hydrogen peroxide generated by ultrasound under the conditions of our experiments and found that it could account for only part of the enzyme inactivation observed. Free radical scavengers/antioxidants were capable of fully protecting the enzymes from ultrasound-induced inactivation. These findings demonstrate that, in addition to hydrogen peroxide, free radicals generated by ultrasound are responsible for the effects.


Title Incidence of cardiac arrhythmias with therapeutic versus diagnostic ultrasound and intravenous microbubbles.
Author Chapman S, Windle J, Xie F, McGrain A, Porter TR.
Journal Ultrasound Med
Volume
Year 2005
Abstract Objective. The purpose of this study was to determine the type of arrhythmias induced with therapeutic versus diagnostic transthoracic low-frequency ultrasound (TLFUS) transducers in the presence of intravenous microbubbles. Methods. Intravenous perfluorocarbon-exposed sonicated dextrose albumim 9PESDA) microbubbles were infused or given as bolus injection while TLFUS was applied in the standard parasternal and apical views with either a 1-MHz therapeutic ultrasound transducer or high-mechanical-index diagnostic ultrasound (1.7 MHz). Results. Significantly more ectopy was produced by the therapeutic transducer, especially at higher-intensity settings in the continuous wave mode after bolus injections of PESDA (P< .001 compared with lower intensities and lower continuous infusion rates). Six patients (15%) had either clinical supraventricular tachycardia or nonsustained ventricular tachycardia after intravenous PESDA with therapeutic TLFUS. IN comparison, diagnostic high-mechanical-index ultrasound produced only isolated ventricular ectopy and no sustained ventricular arrhythmias. Conclusions. Intravenously injected microbubbles and low-frequency therapeutic transducers operating at longer duty cycles and wide beam widths have the capability of eliciting clinically important arrhythmias in patients at high risk for such events.


Title Increase in dehydrogenases in mouse liver exposed to low intensity ultrasound.
Author Kumar RPS, Sebastian GR.
Journal Acoust Lett
Volume
Year 1989
Abstract Mouse liver was exposed 'in vivo' to continuous wave ultrasound of 875 kHz frequency at peak intensities 1 and 1.5 W/cm2 for 1 minutes. The lactate dehydrogenase (LDH) malate dehyrogenase (MDH) and succinic dehydrogenase (SDH) activity was estimated in the liver of exposed and control mice, which were sacrificed on day one, day two, day three, day four and day five following the last irradiation. The three dehydrogenases showed significant increases [P>0.001].


Title Increase in glucose-6-phosphatase and glycogen phosphorylase in liver following insonation of mouse pancreas.
Author Varma BM, Kumar RPS.
Journal Acoust Lett
Volume
Year 1991
Abstract Mouse pancreas was exposed in vivo to a continuous and unfocussed wave ultrasound beam of 875 kHz at a spatial peak intensity of 1 W/cm2 for 300 seconds spread over five days with a gap of exactly 24 hours between each exposure. Measured glucose-6-phosphatase levels showed significant increases while changes in glycogen phosphorylase were minimal in specimens of day zero. The blood glucose level showed a significant decrease. These changes were observed in all the animals sacrificed on day one, day five and day ten. Ultrasound seems to enhance the metabolic pathways in liver associated with cellular energy.


Title Increased G2 duration in sonicated root meristem cells of Pisum sativum.
Author Miller MW.
Journal Environ Exp Bot
Volume
Year 1979
Abstract Roots were exposed to 2.3 MHz ultrasound at intensity levels of 7 and 11 W/cm2. The meristematic cells yielded an intensity dependent delay in their transit through G2 + 1/2 M.


Title Increased heating by diagnostic ultrasound due to nonlinear propagation.
Author Bacon DR, Carstensen EL.
Journal J Acoust Soc Am
Volume
Year 1990
Abstract The heating of tissues by the absorption of ultrasound is an important safety consideration in the use of diagnostic ultrasound. This paper shows that models of ultrasonic heating for this situation need to take account of nonlinear propagation. Measurements were made of the temperature rise in a sample of tissue-mimicking gel, caused by the application of 3.6-MHz focused ultrasonic beams for 3 min. The propagation path to the focus was in water, to mimic the situation where the fetus is scanned through the full bladder. The effect of nonlinear propagation was seen by changing the pressure amplitude of the pulse, while altering the pulsing regime to preserve a constant spatial-peak temporal-average intensity of 1 W cm-2. When nonlinear distortion was present, an enhancement in the temperature rise was observed, which correlated with the value of the shock parameter. The enhancement ratio was typically up to a factor of 3, and the maximum temperature rise observed was 2 degrees C. This enhanced heating was seen both at the surface of the tissue-mimicking gel and after propagation through 23 mm of the material. Under conditions of nonlinear propagation, the maximum heating usually occurs in the prefocal region, rather than at the focus.


Title Increased sister chromatid exchanges in Chinese hamster ovary cells exposed to high intensity pulsed ultrasound.
Author Barnett SB, Miller MW, Cox C, Carstensen EL.
Journal Ultrasound Med Biol
Volume
Year 1988
Abstract This study comprised two repeat experiments in which Chinese hamster ovary (CHO) cells were exposed to nominal peak intensity Im = 2500 W/cm2, 2.5 MHz, pulsed ultrasound. Cells contained in a 0.53 cm diameter chamber in 0.48 cm thick Plexiglas.were exposed to 10 microseconds pulses at 200 Hz prf in 9 sites for 3 min per site for a total duration of 27 min. The -3 dB focal beamwidth was 0.115 cm at an axial distance of 4.8 cm. Analysis of the pooled data from each series of experiments.showed a statistically significant increase in the mean frequency of sister chromatid exchanges (SCE) in exposed compared to control cells. The results show a high degree of variability in the controls and insonated samples, which suggests that large numbers of insonations may be required in studies with SCE to reduce the high.probability of missing an effect. The results of this series of experiments provide the first confirmation of an increase in SCEs following exposure to pulsed ultrasound.


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