ISSN:
0197-8462
Keywords:
calcium concentration
;
pulsed RF fields
;
TEM cell
;
cardiac myocytes
;
Life and Medical Sciences
;
Occupational Health and Environmental Toxicology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Physics
Notes:
The intracellular calcium concentration ([Ca2+]i) of isolated ventricular cardiac myocytes of the guinea pig was measured during the application of pulsed high-frequency electromagnetic fields. The high-frequency fields were applied in a transverse electromagnetic cell designed to allow microscopic observation of the myocytes during the presence of the high-frequency fields. The [Ca2+]i was measured as fura-2 fluorescence by means of digital image analysis. Both the carrier frequency and the square-wave pulse-modulation pattern were varied during the experiments (carrier frequencies: 900, 1,300, and 1,800 MHz pulse modulated at 217 Hz with 14% duty cycle; pulsation pattern at 900 MHz: continuous wave, 16 Hz, and 50 Hz modulation with 50% duty cycle and 30 kHz modulation with 80% duty cycle). The mean specific absorption rate (SAR) values in the solution were within one order of magnitude of 1 mW/kg. They varied depending on the applied carrier frequency and pulse pattern. The experiments were designed in three phases: 500 s of sham exposure, followed by 500 s of field exposure, then chemical stimulation without field. The chemical stimulation (K+-depolarization) indicated the viability of the cells. The K+ depolarization yielded a significant increase in [Ca2+]i. Significant differences between sham exposure and high-frequency field exposure were not found except when a very small but statistically significant difference was detected in the case of 900 MHz/50 Hz. However, this small difference was not regarded as a relevant effect of the exposure. © 1996 Wiley-Liss, Inc.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
