Study type: Medical/biological study (experimental study)

Biological and technical variables in myc expression in HL60 cells exposed to 60 Hz electromagnetic fields. med./bio.

Published in: Bioelectrochem Bioenerg 1997; 44 (1): 111-120

Aim of study (acc. to author)

To explore biological and technical variables which could influence the effects of electromagnetic fields on c-myc gene expression in two HL60 cell populations.

Background/further details

The authors tried to find an explanation for the inability of two groups of investigators (see publication 919, publication 2068) to replicate their results (see publication 895, publication 920). The following criteria were further investigated: different HL60 cell populations (specific growth characteristics, response to the positive control TPA treatment, c-myc transcript level), mRNA extraction procedure (SDS/phenol versus guanidine/phenol), the stability/variability of internal standards, sham exposure set-up (double-wound coils versus single-wound coils), shielding effectiveness.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 60 Hz
Exposure duration: 20 min
field of one coil
Exposure 2: 60 Hz
Exposure duration: 20 min
field of two coils

Exposure 1

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration 20 min
Additional info field of one coil
Exposure setup
Exposure source
Chamber shielding of the coils by cylindrical mu-metal box (30 cm high x 15 cm in radius, 0.040" thick) with a shielding factor of 39 dB
Setup a single pair of Helmholtz coils ( 13 cm x 14 cm ) with 164 turns of copper wire, separated by 8 cm, T-25 flasks including the cells kept on a Plexiglass platform inside the coils
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 8 µT peak value measured - -

Exposure 2

Main characteristics
Frequency 60 Hz
Type
Waveform
Exposure duration 20 min
Additional info field of two coils
Exposure setup
Exposure source
Setup double wound Helmholtz coils ( 13 cm x 14 cm ) with 164 turns of copper wire, separated by 8 cm
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
magnetic flux density 8 µT peak value measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Different c-myc level and cell growth after exposure between the two investigated cell populations were observed.
The response to the positive control TPA differed as well.
The two compared RNA extraction procedures showed different c-myc RNA levels.
There were no differences in the stability of both internal standards and the examined sham exposure set-ups.

Study character:

Study funded by

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