Study type: Medical/biological study (experimental study)

Apoptosis induced by ultraviolet radiation is enhanced by amplitude modulated radiofrequency radiation in mutant yeast cells med./bio.

By: Markkanen A, Penttinen P, Naarala J, Pelkonen J, Sihvonen AP, Juutilainen J
Published in: Bioelectromagnetics 2004; 25 (2): 127-133
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Aim of study (acc. to author)

To investigate whether radiofrequency (RF) electromagnetic fields (EMF) as cofactor are capable of altering the response of the yeast Saccharomyces cerevisiae to UV radiation.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 1 hour
  • SAR: 0.4 W/kg average over time (0.1-0.5 W/kg)
Exposure 2: 900 MHz
Modulation type: CW
Exposure duration: continuous for 1 hour
  • SAR: 0.4 W/kg average over time (0.1-0.5 W/kg)
Exposure 3: 872 MHz
Modulation type: pulsed
Exposure duration: continuous for 1 hour
  • SAR: 3 W/kg average over time (± 35%)
Exposure 4: 872 MHz
Modulation type: CW
Exposure duration: continuous for 1 hour
  • SAR: 3 W/kg average over time (± 35%)

General information

Cells were irradiated with or without previous exposure to ultraviolet radiation (UVB 250 J/m² for 20 min).

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 1 hour
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Chamber aluminium chamber
Additional info The temperature of the cell cultures was controlled by a bed of water under the Petri dishes. Control cell cultures exposed to UV and elevated temperature (37°C) were simultaneously sham exposed in an identical aluminium chamber sited outside the incubator.
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.4 W/kg average over time measured and calculated - 0.1-0.5 W/kg
Measurement and calculation details

The RF power was measured by a Directional Power Meter. Dosimetry for the exposure apparatus was determined by FDTD calculations using commercial code XFDTA and by measuring the electric field profile inside the exposure chamber. The correlation between the measured electric field and the calculated field was excellent.

Exposure 2

Main characteristics
Frequency 900 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 1 hour
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.4 W/kg average over time measured and calculated - 0.1-0.5 W/kg

Exposure 3

Main characteristics
Frequency 872 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 1 hour
Modulation
Modulation type pulsed
Pulse width 0.577 ms
Repetition frequency 217 Hz
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 3 W/kg average over time measured and calculated - ± 35%

Exposure 4

Main characteristics
Frequency 872 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for 1 hour
Modulation
Modulation type CW
Exposure setup
Exposure source
Parameters
Measurand Value Type Method Mass Remarks
SAR 3 W/kg average over time measured and calculated - ± 35%

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

UV exposure increased apoptosis of both yeast strains and reduced the number of viable yeast cells, compared to sham-exposed and temperature control. None of the RF field exposures alone had significant effects on apoptosis, cell number, or colony forming ability.
Pulsed RF exposure significantly enhanced UV-induced apoptosis in cdc48-mutant cells, but no effect was observed in cells exposed to unmodulated fileds. The data indicate that amplitude modulated RF fields, together with known damaging agents, can affect the cell death process in mutated yeast cells.

Study character:

Study funded by

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