Medical/biological study (experimental study)

Measurement of DNA damage and apoptosis in Molt-4 cells after in vitro exposure to radiofrequency radiation med./bio.

By: Hook GJ, Zhang P, Lagroye I, Li L, Higashikubo R, Moros EG, Straube WL, Pickard WF, Baty JD, Roti Roti JL

Published in: Radiat Res 2004; 161 (2): 193-200

Aim of study (acc. to author)

To study whether exposure to radiofrequency irradiation can induce DNA damage or apoptosis, Lymphoblastoid cells were exposed to radiofrequency fields at frequencies and modulations of the type used by wireless communication devices.
The study was conducted to determine if the effects of iDEN- and TDMA-modulated radiofrequency signals that were observed previously (publication 2112) could be replicated using the RTL (Radial Transmission Line) exposure system.

Endpoint

genotoxicity/mutation: DNA damage/DNA single-strand breaks
cell viability/cell division/proliferation: apoptosis

Exposure

- CDMA
- FDMA
- TDMA
- mobile communications
- iDEN

Exposure	Parameters
Exposure 1: 813.56 MHz Modulation type: pulsed Exposure duration: continuous for 2, 3 or 21 h	SAR: 2.4 mW/kg mean SAR: 24 mW/kg mean
Exposure 2: 836.55 MHz Modulation type: pulsed Exposure duration: continuous for 2, 3 or 21 h	SAR: 2.6 mW/kg mean SAR: 26 mW/kg mean
Exposure 3: 847.74 MHz Exposure duration: continuous for 2 or 24 h	SAR: 3.2 W/kg mean
Exposure 4: 835.62 MHz Exposure duration: continuous for 2 or 24 h	SAR: 3.2 W/kg mean

General information

Each experiment included a radiation control exposed to ¹³⁷Cs γ rays at 0.18 Gy/min for a total dose of 1 Gy, and a hyperthermia control exposed to 44°C for 20 min.

Exposure 1

Main characteristics

Frequency	813.56 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2, 3 or 21 h

Modulation

Modulation type	pulsed
Additional info	iDEN

Exposure setup

Exposure source	radial waveguide
Chamber	The exposure facility consisted of a number of Radial Transmission Lines (RTL) located in a temperature controlled room. A description and comprehensive characterisation has been published previously [Moros et al., 1999; Pickard et al., 1999 and 2000].
Setup	T-75 flasks containing 40 ml of complete medium were gassed with 5% CO₂ and 95% air and capped tightly. Temperature controllers of the RTLs were calibrated to maintain the culture medium in the flasks at 37.0 ± 0.3°C.
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2.4 mW/kg	mean	measured	-	-
SAR	24 mW/kg	mean	measured	-	-

Measurement and calculation details

Dosimetry was based on relating the weighted mean SAR measured in a designated flask to the SAR of the treatment flasks by comparing the response of a diode at these locations [Moros et al., 1999].

Exposure 2

Main characteristics

Frequency	836.55 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2, 3 or 21 h

Modulation

Modulation type	pulsed
Additional info	TDMA

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2.6 mW/kg	mean	measured	-	-
SAR	26 mW/kg	mean	measured	-	-

Exposure 3

Main characteristics

Frequency	847.74 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 or 24 h

Modulation

Modulation type	cf. additional info
Additional info	CDMA

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	3.2 W/kg	mean	measured	-	-

Exposure 4

Main characteristics

Frequency	835.62 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 or 24 h

Modulation

Modulation type	cf. additional info
Additional info	FDMA

Exposure setup

Exposure source	same setup as exposure 1
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	3.2 W/kg	mean	measured	-	-

Reference articles

Pickard WF et al. (2000): Experimental and numerical determination of SAR distributions within culture flasks in a dielectric loaded radial transmission line
Moros EG et al. (1999): The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks
Pickard WF et al. (1999): Simplified model and measurement of specific absorption rate distribution in a culture flask within a transverse electromagnetic mode exposure system

Exposed system:

intact cell/cell culture
Molt-4 T (lymphoblastoid cells)

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA damage/DNA single-strand breaks (comet assay; comet length; comet moment ((amount of DNA at distance x) x (distance x))/total DNA))
cell viability/cell division/proliferation: apoptosis (annexin V affinity assay; flow cytometry)

Investigated system:

DNA/RNA
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No statistically significant difference in the level of DNA damage or apoptosis was revealed between sham-treated cells and cells exposed to radiofrequency electromagnetic fields for any frequency, modulation or exposure time.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Motorola

Palumbo R et al. (2008): Exposure to 900 MHz radiofrequency radiation induces caspase 3 activation in proliferating human lymphocytes
Joubert V et al. (2008): Apoptosis is Induced by Radiofrequency Fields through the Caspase-Independent Mitochondrial Pathway in Cortical Neurons
Huang TQ et al. (2008): Molecular responses of Jurkat T-cells to 1763 MHz radiofrequency radiation
Joubert V et al. (2007): No apoptosis is induced in rat cortical neurons exposed to GSM phone fields
Chauhan V et al. (2007): Evaluating the biological effects of intermittent 1.9 GHz pulse-modulated radiofrequency fields in a series of human-derived cell lines
Joubert V et al. (2006): Microwave exposure of neuronal cells in vitro: Study of apoptosis
Hirose H et al. (2006): Phosphorylation and gene expression of p53 are not affected in human cells exposed to 2.1425 GHz band CW or W-CDMA modulated radiation allocated to mobile radio base stations
Phillips JL et al. (1998): DNA damage in Molt-4 T-lymphoblastoid cells exposed to cellular telephone radiofrequency fields in vitro

Measurement of DNA damage and apoptosis in Molt-4 cells after in vitro exposure to radiofrequency radiation med./bio.

Aim of study (acc. to author)

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Measurement and calculation details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 3

Main characteristics

Modulation

Exposure setup

Parameters

Exposure 4

Main characteristics

Modulation

Exposure setup

Parameters

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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