Medical/biological study (experimental study)

Effects of modulated microwave radiation at cellular telephone frequency (1.95 GHz) on X-ray-induced chromosome aberrations in human lymphocytes in vitro med./bio.

By: Manti L, Braselmann H, Calabrese ML, Massa R, Pugliese M, Scampoli P, Sicignano G, Grossi G

Published in: Radiat Res 2008; 169 (5): 575-583

Aim of study (acc. to author)

This in vitro study was conducted to study the influence of 1.95 GHz UMTS modulated radio frequency exposure on X ray induced chromosome aberrations in human lymphocytes.

Background/further details

The lymphocytes were obtained from four healthy male donors aged between 23 and 30 years.

Endpoint

genotoxicity/mutation: chromosome aberrations

Exposure

- CDMA
- mobile communications
- digital mobile phone
- UMTS

Exposure	Parameters
Exposure 1: 1.95 GHz Exposure duration: continuous for 24 h	SAR: 2 W/kg mean SAR: 0.5 W/kg mean

Exposure 1

Main characteristics

Frequency	1.95 GHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 24 h

Modulation

Modulation type	cf. additional info
Additional info	UMTS signal meeting the WCDMA standard, according to the 3GPP 3.5 2001-03 specifications (five power-controlled user data channels and one control channel)

Exposure setup

Exposure source	waveguide WR 430, rectangular, 109.2 mm x 54.6 mm
Chamber	The standardized exposure device has been described in [Sannino et al., 2006 and Calabrese et al., 2006]. Two identical waveguides, one for RF and one for sham exposure, were housed in a commercial incubator at 37°C with 95% air and 5% CO₂.
Setup	A total of eight 35-mm Petri dishes were inoculated with lymphocytes from each donor. Four dishes, each filled with 3 ml of cell suspension, were held by a plastic stand in each waveguide. The distance between the samples allowed simultaneous exposure at two different SARs. The induced electric field was essentially parallel to the sample surface.
Sham exposure	A sham exposure was conducted.
Additional info	The feeding end was a coaxial waveguide adapter, the other end terminated with a fixed short circuit. The center of the samples was at a distance of 0.5 λ from the short circuit in order to achieve the best trade-off between efficiency and SAR uniformity.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2 W/kg	mean	determined by power loss	-	-
SAR	0.5 W/kg	mean	determined by power loss	-	-

Additional parameter details

Two of the dishes in each waveguide were given 4 Gy of X rays immediately before RF or sham exposure (one dish per SAR). The X rays were produced by a Thomson tube (250 kVp, 0.8 Gy/min) and filtered by 1-mm thick copper foil.

Measurement and calculation details

Incident and reflected powers were measured using a bidirectional power sensor connected to a computer continuously adjusting the power level of the signal generator to the required SAR. Measurements of local SAR and power efficiency showed good agreement with the calculated values. The ratio between the SAR standard deviation and the average SAR was 0.33 in all four samples. The measured increase in temperature during the RF exposure at 2 W/kg was 0.2 ± 0.1°C, which was considered sufficiently low to exclude damage induced by thermal processes.

Reference articles

Sannino A et al. (2006): Evaluation of Cytotoxic and Genotoxic Effects in Human Peripheral Blood Leukocytes Following Exposure to 1950-MHz Modulated Signal
Calabrese M et al. (2006): A high-efficiency waveguide applicator for in vitro exposure of mammalian cells at 1.95 GHz

Exposed system:

intact cell/cell culture

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: chromosome aberrations (e.g. symmetrical and asymmetrical chromosomal interchanges, acentric fragments; fraction of aberrrant cells, frequency of totale chromosome exchanges per cell): fluorescence in situ hybridization

Investigated system:

DNA/RNA
chromosome 1 and 2

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The UMTS exposure did not cause differences in the fraction of X-ray-induced aberrant cells. However, a small but statistically significant increase in the frequency of X-ray-induced chromosome exchanges per cell, especially at the specific absorption rate of 2 W/kg was observed.
In conclusion, although the 1.95 GHz UMTS modulated radiofrequency field does not exacerbate the yield of aberrant cells caused by ionizing radiation, the overall burden of X-ray-induced chromosomal damage per cell in first-mitosis lymphocytes may be enhanced at 2.0 W/kg SAR.

Study character:

medical/biological study
experimental study
full/main study
blind study

Study funded by

Centre of Competence on Information and Communication Technologies, Regione Campania, Italy
Project "Wireless Technology Health Risks", Italy

Zeni O et al. (2012): Radiofrequency radiation at 1950 MHz (UMTS) does not affect key cellular endpoints in neuron-like PC12 cells
Bourthoumieu S et al. (2010): Cytogenetic Studies in Human Cells Exposed In Vitro to GSM-900 MHz Radiofrequency Radiation Using R-Banded Karyotyping
Schwarz C et al. (2008): Radiofrequency electromagnetic fields (UMTS, 1,950 MHz) induce genotoxic effects in vitro in human fibroblasts but not in lymphocytes
Zeni O et al. (2008): Evaluation of genotoxic effects in human leukocytes after in vitro exposure to 1950 MHz UMTS radiofrequency field
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