Study type: Medical/biological study (experimental study)

NF-kappaB DNA-binding activity after high peak power pulsed microwave (8.2 GHz) exposure of normal human monocytes med./bio.

By: Natarajan M, Vijayalaxmi, Szzliagyl M, Roldan FN, Meltz ML
Published in: Bioelectromagnetics 2002; 23 (4): 271-277
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Aim of study (acc. to author)

To determine whether exposure of human cells to high peak power pulsed microwave radiation can potentiate the activation of the important nuclear transcription factor NF-kB.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 8.2 GHz
Modulation type: pulsed
Exposure duration: continuous for 90 min

Exposure 1

Main characteristics
Frequency 8.2 GHz
Type
Exposure duration continuous for 90 min
Modulation
Modulation type pulsed
Pulse width 2.2 µs
Duty cycle 0.22 %
Repetition frequency 1,000 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 146 cm
Chamber The anechoic chamber was 6.1 m x 4.3 m x 3.1 m. The radiation from the horizontal antenna was directed vertically downward toward the exposure flasks using a reflector.
Setup Four flasks were placed into the water bath (24.5 cm x 21 cm), parallel and equidistant (1.3 cm) from each other and the center of the bath (a 2 x 2 parallel array, with the caps pointed outward).
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power density 50 W/m² average over time measured - ±10%
SAR 10.8 W/kg mean calculated - ± 7.1 W/kg
Measurement and calculation details

Power density measurements were made using a power meter with a probe. The distribution was ±10% of the average at the positions of the four T-25 flasks. The average SAR at the bottom of the flask, calculated by FDTD analysis, was 10.8 ± 7.1 W/kg. In an area of approximately 2 cm x 4 cm in the central part of the flask, the SAR values were within 20% of this average SAR. The range of SARs was from 0.0002 to 29.43 W/kg, with 90, 75, 50, 25, and 10% of cells being exposed to SARs greater than 1.85, 5.55, 10.0, 14.45, and 22.05 W/kg, respectively. The center point of the flask was not the location of the highest SAR.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

The results showed a profound increase (3.6 fold) in the DNA binding activity of NF-kB in monocytes at 4 h after the pulsed radiofrequency radiation compared to sham irradiated controls. The results provide evidence that high peak power pulsed radiofrequency exposure can perturb the cell and inititate cell signaling pathways. It is not said that the cause is a nonthermal mechanisms.

Study character:

Study funded by

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