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Comparative effects of extremely high power microwave pulses and a brief CW irradiation on pacemaker function in isolated frog heart slices
Author(s) -
Pakhomov Andrei G.,
Mathur Satnam P.,
Doyle Joanne,
Stuck Bruce E.,
Kiel Jonathan L.,
Murphy Michael R.
Publication year - 2000
Publication title -
bioelectromagnetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.435
H-Index - 81
eISSN - 1521-186X
pISSN - 0197-8462
DOI - 10.1002/(sici)1521-186x(200005)21:4<245::aid-bem1>3.0.co;2-8
Subject(s) - microwave , irradiation , microwave irradiation , materials science , biophysics , chemistry , biomedical engineering , medicine , biology , physics , quantum mechanics , nuclear physics
The existence of specific bioeffects due to high peak power microwaves and their potential health hazards are among the most debated but least explored problems in microwave biology. The present study attempted to reveal such effects by comparing the bioeffects of short trains of extremely high power microwave pulses (EHPP, 1 μs width, 250–350 kW/g, 9.2 GHz) with those of relatively low power pulses (LPP, 0.5–10 s width, 3–30 W/g, 9.2 GHz). EHPP train duration and average power were made equal to those of an LPP; therefore both exposure modalities produced the same temperature rise. Bioeffects were studied in isolated, spontaneously beating slices of the frog heart. In most cases, a single EHPP train or LPP immediately decreased the inter‐beat interval (IBI). The effect was proportional to microwave heating, fully reversible, and easily reproducible. The magnitude and time course of EHPP‐ and LPP‐induced changes always were the same. No delayed or irreversible effects of irradiation were observed. The same effect could be repeated in a single preparation numerous times with no signs of adaptation, sensitization, lasting functional alteration, or damage. A qualitatively different effect, namely, a temporary arrest of preparation beats, could be observed when microwave heating exceeded physiologically tolerable limits. This effect also did not depend on whether the critical temperature rise was produced by LPP or EHPP exposure. Within the studied limits, we found no indications of EHPP‐specific bioeffects. EHPP‐ and LPP‐induced changes in the pacemaker rhythm of isolated frog heart preparation were identical and could be entirely attributed to microwave heating. Bioelectromagnetics 21:245–254, 2000. © 2000 Wiley‐Liss, Inc.