In a previous study (publication 862) a statistically significant enhancement of transformation response by TPA in cells exposed to 2.45 GHz microwaves was shown.
This study was intended to show that the enhancement of neoplastic transformation due to electromagnetic fields plus TPA is dependent on the level of electromagnetic radiation and is additive with doses of X-rays given as a cocarcinogen.
Actively growing cells were exposed for 24 h to 2.45-GHz microwaves with or without subsequent incubation in TPA (0.1 µg/ml). In separate experiments, a 24-h electromagnetic field exposure at 4.4 W/kg was preceded or followed by X-radiation at 0.5, 1, or 1.5 Gy (with or without subsequent incubation in TPA).
Modulation type: pulsed
Exposure duration: continuous for 24 h
|Repetition frequency||120 Hz|
|Setup||Culture flasks immersed in water-bath. The cellular attachment plane was located more than 20 wavelengths away from the source and was positioned perpendicularly to the direction of EM wave propagation, parallel to EM field polarization plane. Shielded sham control flasks were located at the bottom of the water bath at a depth of 11 cm.|
|Additional info||In a separate experiment, samples were exposed to 4.4 W/kg and were irradiated to x-ray prior or after the exposure at 0.5, 1 or 1.5 Gy.|
|electric field strength||18 V/m||peak value||estimated||-||56 V/m and 120 V/m|
|magnetic flux density||90 nT||peak value||estimated||-||0.27 µT and 0.56 µT|
|SAR||0.1 W/kg||unspecified||unspecified||-||cellular monolayers were placed 8.7 cm below water level|
|SAR||1 W/kg||unspecified||unspecified||-||cellular monolayers were placed 4.8 cm below water level|
|SAR||4.4 W/kg||unspecified||unspecified||-||cellular monolayers were placed 2.3 cm below water level|
There were no significant effects of TPA or electromagnetic fields on plating efficiency, or on survival in combination with X-radiation.
The electromagnetic field or TPA exposure alone had no effect on induction of neoplastic transformation. However enhancement of transformation due to electromagnetic fields plus TPA was highly significant (synergistic dose-dependent effect). It ranged up to a level equivalent to that produced by 1.5 Gy of X-rays. The frequency of neoplastic transformation was dependent on the level of electromagnetic radiation and was additive with doses of X-rays given as a cocarcinogen.