Study type: Medical/biological study (experimental study)

[The reaction of human T-lymphocytes (Jurkat) to high-frequency electromagnetic fields] med./bio.

Die Wirkung von hochfrequenten elektromagnetischen Feldern auf menschliche kultivierte T-Lymphozyten (Jurkat)

By: Meyer R, Gollnick F, Wolke S, Conrad G, Bock H
Published in: Edition Wissenschaft 1996; 10: 3-22
Journal not peer-reviewed
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Aim of study (acc. to author)

To investigate the effects of pulsed high-frequency fields on the [Ca2+]i in a T-cell line, Jurkat cells.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 500 s
  • power: 5 W peak value
  • SAR: 15.4 mW/kg mean (averaged over time and space)
  • SAR: 123.2 mW/kg peak value
Exposure 2: 1,800 MHz
Modulation type: pulsed
Exposure duration: continuous for 500 s
  • power: 2.8 W peak value
  • SAR: 13.5 mW/kg mean (averaged over time and space)
  • SAR: 96.3 mW/kg peak value

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 500 s
Modulation
Modulation type pulsed
Duty cycle 14 %
Repetition frequency 217 Hz
Pulse type rectangular
Exposure setup
Exposure source
Chamber The TEM cell was designed to fit on top of the inverted microscope and consisted of two separate parts, i.e. the upper part with the septum (the TEM cell itself), and the rectangular bottom plate containing the 1-cm test chamber for holding the biological material. The bottom of this chamber consisted of a glass coverslip and a 1-mm metal mesh made of 0.05-mm wire and provided shielding while allowing optical observation. A detailed description can be found in the partial report on "Expositionseinrichtungen" [Neibig, 1996].
Setup The sample volume (200 µl perfusion fluid with cells) in a Plexiglas container was maintained at a constant temperature by an exchange of the fluid preheated to 37 °C and an additional heating fluid running through a circular channel around the sample volume.
Sham exposure A sham exposure was conducted.
Additional info An experimental run consisted of three phases each lasting 500 s. The first phase without any exposure was followed by field or sham exposure. During the third phase a chemical stimulation was performed in order to provoke a response of the cells which served as positive control.
Parameters
Measurand Value Type Method Mass Remarks
power 5 W peak value measured - -
SAR 15.4 mW/kg mean measured and calculated - averaged over time and space
SAR 123.2 mW/kg peak value measured and calculated - -
Measurement and calculation details

The SAR value achieved was determined by combined measurements and calculations. Additional information can be found in the partial report on "Expositionseinrichtungen" [Neibig, 1996]. Field distribution and SAR for 1 W CW were calculated using the "MAFIA" program. The power transmitted into the TEM cell was measured separately for all applied signals using a bolometer. Additionally, control measurements were performed with a spectrum analyzer and a millivoltmeter. Finally, the actual SAR values were calculated for both carrier frequencies with their pulse patterns. The SAR values calculated on this basis were only spatial mean values. The metal mesh, however, created local field inhomogeneities at the level of the cells since the field lines converged towards the wires of the mesh. Calculations on this showed that the field strength varied by a factor of 3 and SAR values thus by a factor of 9.

Exposure 2

Main characteristics
Frequency 1,800 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 500 s
Modulation
Modulation type pulsed
Duty cycle 14 %
Repetition frequency 217 Hz
Pulse type rectangular
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
power 2.8 W peak value measured - -
SAR 13.5 mW/kg mean measured and calculated - averaged over time and space
SAR 96.3 mW/kg peak value measured and calculated - -

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • during exposure

Main outcome of study (acc. to author)

The number of cells with calcium oscillations during exposure to the 900 MHz field was not different from that during sham exposure. In the case of 1800 MHz fields 17.7% of cells started calcium oscillations during exposure, whereas only 10.9% of cells started calcium oszillations during sham exposure. This might indicate an increase in calcium oscillations due to the field exposure. Evaluation of the averaged [Ca2+]i showed small increase in [Ca2+]i soon after the field had been switched on. This increase was present in both exposed groups, 900 and 1800 MHz, but it was visible in any of the sham exposed groups.

Study character:

Study funded by

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