Study type: Medical/biological study (experimental study)

Effect of isothermal radiofrequency radiation on cytolytic T lymphocytes med./bio.

By: Cleary SF, Du Z, Cao G, Liu LM, McCrady C
Published in: FASEB J 1996; 10 (8): 913-919
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Aim of study (acc. to author)

To study the effects of radiofrequency irradiation on interleukin-2-dependent proliferation of cytolytic T lymphocytes (CTLL-2).

Background/further details

After antigenic activation CTLL-2 express high-affinity receptors for the hormone interleukin-2. Binding of interleukin-2 is necessary and sufficient for T cell proliferation. After exposure to radiofrequency cells were cultured at various physiological concentrations of interleukin-2 (0, 0.62, 1.25, 2.5, 5, 10, 20, or 40 U/ml).
CTLL-2 cells were also incubated for 2 h at 37, 38, 39, 40, or 41°C without electromagnetic field exposure (temperature control).

Endpoint

Exposure

Exposure Parameters
Exposure 1: 2.45 GHz
Modulation type: CW
Exposure duration: continuous for 2 h
Exposure 2: 2.45 GHz
Modulation type: pulsed
Exposure duration: continuous for 2 h

Exposure 1

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration continuous for 2 h
Modulation
Modulation type CW
Exposure setup
Exposure source
Setup Cells were simultaneously RF and sham exposed in identical waveguide exposure chambers maintaining isothermal conditions at 37 ± 0.1°C as described previously [Liu et al., 1988].
Sham exposure A sham exposure was conducted.
Additional info Thermal control cultures were incubated for 2 h at 37, 38, 39, 40, or 41°C in the chambers used for MW exposure.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 139 V/m - measured - -
SAR 50 W/kg - measured - -
electric field strength 98.4 V/m - measured - -
SAR 25 W/kg - measured - -
electric field strength 44 V/m - measured - -
SAR 5 W/kg - measured - -
Measurement and calculation details

SAR measurements, intrasample temperature and SAR distributions, and temperature control procedures were previously described [Liu et al., 1988].

Exposure 2

Main characteristics
Frequency 2.45 GHz
Type
Exposure duration continuous for 2 h
Modulation
Modulation type pulsed
Pulse width 6.67 ms
Repetition frequency 50 Hz
Additional info

simulating PCS modulation
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
electric field strength 76.2 V/m peak value measured - -
SAR 15 W/kg peak value measured - -
electric field strength 44 V/m average over time measured - -
SAR 5 W/kg average over time measured - -

Reference articles

  • Liu LM et al. (1988): Effects of 2.45-GHz microwave and 100-MHz radiofrequency radiation on liposome permeability at the phase transition temperature

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Exposure to 2450 MHz radiofrequency irradiation at specific absorption rates of greater than 25 W/kg induced a consistent, statistically significant reduction in CTLL-2 proliferation, especially at low interleukin-2 concentrations. At lower specific absorption rates, exposure increased CTLL-2 proliferation immediately after exposure but reduced 24 h postexposure proliferation.
Radiofrequency irradiation effects depended on the mitotic state of the cells at the time of exposure. Comparison of the effects of temperature elevation (temperature control) and radiofrequency irradiation indicated significant qualitative and quantitative differences.

Study character:

Study funded by

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