Victor Ciaravino

Pulsed enhancement of acoustic cavitation: A postulated model

Abstract Iodine-131 labeled sodium iodide was used to demonstrate an iodine release reaction indicative of cavitation activity. Exposure of Na131I at varying pulsed regimes (1:1 duty cycle, 60 sec-60 μsec pulse duration) and intensities (10–30W/cm2) resulted in an increased efficiency of pulsed ultrasound to produce iodine release compared to continous wave exposures. A model based on the concurrent operation of two mechanisms has been proposed to explain this phenomenon.

Lysis and viability of cultured mammalian cells exposed to 1 MHz ultrasound

Abstract HeLa and CHO cells were exposed for 1 to 15 min to 1 MHz ultrasound at intensities up to 30 W/cm 2 . The threshold for cell lysis was approximately 1 W/cm 2 with the maximum effect at 10 W/cm 2 . Among the intact cells there was a decreased viability as determined both by trypan blue exclusion and by colony-forming ability; the intensity vs. response curve was similar to that fur cell lysis. Preliminary evidence also suggests that a decrease in proliferation rate and an increased incidence of giant cells occur for the remaining intact and viable cells.

Effect of 2 MHz Ultrasound on DNA, RNA and Protein Synthesis in Pisum Sativum Root Meristem Cells

The amounts of DNA, RNA and protein synthesis were determined in Pisum sativum root meristem cells at various times after a 1 min exposure to 1 MHz ultrasound at a power density of 30 W/cm2. Immediate depressions in all three macromolecular syntheses occurred after sonication, followed by an apparent recovery several hours later. These events appear to correlate in time with the subsequent reduction and recovery in mitotic index in Pisum sativum root meristem cells exposed to 2 MHz ultrasound.

Lack of ultrasound effect on in vitro human lymphocyte sister chromatid exchange

The frequency of sister chromatid exchanges (SCEs) in human lymphocytes cultured in vitro was not affected by a 30 min exposure to a 2.25 MHz focused ultrasound beam (from a clinical diagnostic unit with a pulse repetition rate of 1000 Hz, a 1 mu sec burst duration, and a 2-200 W/cm2 maximum intensity). A 30 sec exposure to continuous wave 1 MHz 2 W/cm2 (SP) ultrasound from an experimental device lysed 10-15% of the lymphocytes; there was no increase in SCEs in the survivors relative to unexposed controls. Treatment of lymphocytes with 0.033 micrograms/ml mitomycin-C, a known SCE inducer, increased the frequency of SCEs about 4 times above control levels.

THE EFFECT OF 1 MHz ULTRASOUND ON THE PROLIFERATION OF SYNCHRONIZED CHINESE HAMSTER V-79 CELLS

Abstract Mitotically synchronized Chinese hamster V-79 cells were exposed to continous wave 1 MHz ultrasound at a spatial peak intensity of 3 W/cm 2 at 37°C. A fraction of the cells was lysed immediately, and a second fraction was rendered nonviable. Many of these intact but nonviable cells appeared to be morphologically damaged. The remaining viable cells formed smaller colonies than did unexposed controls, apparently because of the death of one daughter cell at or shortly after the first division. There were no apparent effects on cells surviving beyond that period, and progression through the cell cycle was unperturbed.

Diagnostic insonation of extra utero human placentas: No effect of lymphocytic sister chromatid exchange

SummaryFreshly delivered human placentas were exposed to ultrasound for 30 min using a diagnostic linear array unit. Blood was then drawn and cultured in the presence of bromodeoxyuridine, and the frequencies of sister chromatid exchanges (SCE) in the lymphocytes determined. There was no statistically significant difference in SCE frequencies between control and exposed cells; the frequencies of SCEs per cell ranged from 4.50 to 6.02 for control and from 4.66 to 6.10 for exposed cells in five separate experiments. Positive control mitomycin C treated cells were significantly affected, with more than 50 SCEs per cell.

Lack of effect of high-intensity pulsed ultrasound on sister chromatid exchange and in vitro chinese hamster ovary cell viability

The frequency of sister chromatid exchanges (SCEs) in in vitro Chinese hamster ovary cells and their viability were not affected by 3-min exposures to 2-4 MHz, focused, pulsed ultrasound with a pulse repetition rate of 200 Hz, pulse duration of 10 mu sec and intensities (SPTP) of 500 W/cm2 and 2500 W/cm2. The viability results are consistent with those reported elsewhere; the SCE response does not verify a specific previously reported positive response.

Ceramic Electrodes for ELF Bioeffects Studies

Whenever metal electrodes are used for chronic exposure of biological material to ELF electric fields in a liquid medium, there is a possibility that observed effects are caused directly by ions from the electrodes rather than by the electric field. The problem can be avoided by using insulated electrodes, but ordinarily this severely limnits the fields which can be obtained in the medium. We show here that by using high dielectric constant ceramic electrodes, current densities greater than 10 A/M2 are achievable at frequencies above 50 Hz.

Lack of Effect of High Intensity Pulsed Ultrasound on Sister Chromatid Exchange

The frequency of sister-chromatid exchanges (SCEs) in in vitro Chinese hamster ovary cells and their viamity were not affected by 3 min exposures to 2-4 MHz, focused, pulsed ultrasound with a pulse repetition r ate of 200 Hz, pulse duration of 10 psec and intensities (SPTP) of 500 and 2500 W/cm2. The viability results are consistent with those reported elsewhere; the SCE response does not verify a specific previously r eported positive response.

Absence of an Ultrasound Effect on In Vitro Lymphocyte Sister Chromatid Exchange

The frequency of sister chromatid exchanges (SCEs) in human lymphocytes cultured in vitro was not affected by a 30 min exposure to 2.25 MHz focused ultrasound beam (from a clinical diagnostic unit with a pulse repetition rate of 1000 Hz, a 1 ..mu.. sec burst duration, and a 2-200 W/cm/sup 2/ maximum intensity. A 30 sec exposure to CW 1 MHz 2 W/cm/sup 2/ (SP) ultrasound from an experimental device lysed 10-15% of the lymphocytes; there was no increase in SCEs in the survivors relative to unexposed controls. Treatment of lymphocytes with 0.033 ..mu..g/ml mitomycin-C, a known SCE inducer, increased the frequency of SCEs about 4 times above control levels.