Medical/biological study (experimental study)

Evaluation of genotoxic effects in human peripheral blood leukocytes following an acute in vitro exposure to 900 MHz radiofrequency fields med./bio.

By: Zeni O, Romano M, Perrotta A, Lioi MB, Barbieri R, d'Ambrosio G, Massa R, Scarfi MR

Published in: Bioelectromagnetics 2005; 26 (4): 258-265

Aim of study (acc. to author)

To investigate the induction of genotoxic effects on human peripheral blood leukocytes following 2 h exposure to 900 MHz (GSM signal) radiofrequency irradiation.

Background/further details

Positive controls were also provided by using methyl methanesulfonate (for comet assay) and mitomycin C (for chromosome aberration or sister chromatid exchange tests).

Endpoint

genotoxicity/mutation: occurence of DNA damages

Exposure

- microwaves
- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 2 h	SAR: 0.3 W/kg mean (unspecified) SAR: 1 W/kg mean (unspecified)

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz
Pulse type	rectangular
Additional info	The signal was both phase modulated by Gaussian minimum shift keying (GMSK) and amplitude modulated (rectangular pulses, 217 Hz) according to the TDMA technique. The modulating bit rate was 1/T = 270.833 kbit/s and the 3 dB bandwidth, B, was such that BT = 0.3. Voice modulation was simulated by sending a 9 bit pseudorandom sequence.

Exposure setup

Exposure source	waveguide microwave signal generator
Chamber	The exposure chamber was made of a rectangular waveguide (124 x 248 x 500 mm), surrounded by a thermostated (37.0 ± 0.1 °C) water jacket, and two coax-to-waveguide adapters. The 8-ml samples were located in four T25 culture flasks inserted into the waveguide. The narrow side of the waveguide and the E field were horizontal, thus parallel to the culture liquid layer, which was 3 mm thick.
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.3 W/kg	mean	measured and calculated	unspecified	-
SAR	1 W/kg	mean	measured and calculated	unspecified	-

Measurement and calculation details

Both power sensors were connected to a computer; thus the incident, the reflected and the transmitted powers were measured during the actual exposure of the biological samples. From these, the power absorbed by the sample and the applicator efficiency could be evaluated.

Reference articles

Kuster N et al. (2000): Recommended minimal requirements and development guidelines for exposure setups of bio-experiments addressing the health risk concern of wireless communications

Exposed system:

intact cell/cell culture
human peripheral blood leukocytes

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA damages (alkaline single-cell gel electrophoresis (Comet assay); chromosome aberration; sister chromatid exchange (after phytohemagglutinin stimulation))
cell viability/cell division/proliferation: cell proliferation (mitotic index)

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No statistically significant differences were found in exposed samples in comparison with sham-exposed ones for all the parameters investigated. On the contrary, the positive controls gave a statistically significant increase in DNA damage in all cases.
The data do not support the hypothesis that 900 MHz radiofrequency field exposure induces DNA damage in human peripheral blood leukocytes.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministero dell' Università e della Ricerca (MIUR (formerly MURST (Ministero dell' Università e della Ricerca Scientifica e Tecnologica); Ministry of University and Research), Italy

Speit G et al. (2013): Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in HL-60 cells are not reproducible
Bourthoumieu S et al. (2010): Cytogenetic Studies in Human Cells Exposed In Vitro to GSM-900 MHz Radiofrequency Radiation Using R-Banded Karyotyping
Franzellitti S et al. (2010): Transient DNA damage induced by high-frequency electromagnetic fields (GSM 1.8GHz) in the human trophoblast HTR-8/SVneo cell line evaluated with the alkaline comet assay
Sannino A et al. (2009): Induction of adaptive response in human blood lymphocytes exposed to radiofrequency radiation
Hansteen IL et al. (2009): Cytogenetic effects of exposure to 2.3 GHz radiofrequency radiation on human lymphocytes in vitro
Huang TQ et al. (2008): Molecular responses of Jurkat T-cells to 1763 MHz radiofrequency radiation
Kim JY et al. (2008): In vitro assessment of clastogenicity of mobile-phone radiation (835 MHz) using the alkaline comet assay and chromosomal aberration test
Speit G et al. (2007): Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in cultured mammalian cells are not independently reproducible
Baohong W et al. (2007): Evaluating the combinative effects on human lymphocyte DNA damage induced by ultraviolet ray C plus 1.8 GHz microwaves using comet assay in vitro
Juutilainen J et al. (2007): Micronucleus frequency in erythrocytes of mice after long-term exposure to radiofrequency radiation
Maes A et al. (2006): Cytogenetic investigation of subjects professionally exposed to radiofrequency radiation
Scarfi MR et al. (2006): Exposure to radiofrequency radiation (900 MHz, GSM signal) does not affect micronucleus frequency and cell proliferation in human peripheral blood lymphocytes: an interlaboratory study
Vijayalaxmi (2006): Cytogenetic studies in human blood lymphocytes exposed in vitro to 2.45 GHz or 8.2 GHz radiofrequency radiation
Sannino A et al. (2006): Evaluation of Cytotoxic and Genotoxic Effects in Human Peripheral Blood Leukocytes Following Exposure to 1950-MHz Modulated Signal