Medical/biological study (experimental study)

Evaluation of genotoxic effects in human leukocytes after in vitro exposure to 1950 MHz UMTS radiofrequency field med./bio.

By: Zeni O, Schiavoni A, Perrotta A, Forigo D, Deplano M, Scarfi MR

Published in: Bioelectromagnetics 2008; 29 (3): 177-184

Aim of study (acc. to author)

To study whether intermittent exposures at the frequency of 1950 MHz and UMTS signal are able to induce genotoxic effects in human blood cells.

Background/further details

For each donor (n=6) several experimental conditions were considered to check for a possible different sensitivity through the cell cycle (via micronucleus assay): (1) intermittent exposures of un-stimulated lymphocytes (resting cells) for 24 h, followed by 44 h exposure after phytohemagglutinin stimulation, to test radiofrequency exposure in G0 phase-G1 phase-S phase-G2 phase stages; (2) intermittent exposures for 44 h after phytohemagglutinin stimulation, to test radiofrequency exposure in G1 phase-S phase-G2 phase stages; (3) intermittent exposures of un-stimulated lymphocytes (resting cells) for 24 h before phytohemagglutinin stimulation. For comet assay un-stimulated lymphocytes (resting cells) were exposed for 24 h.
Positive controls were performed by treating cells with mitomycin C and methyl methanesulfonate for micronucleus and comet assays, respectively.

Endpoint

genotoxicity/mutation: formation of micronucleus during different cell cycle stages

Exposure

- mobile communications
- digital mobile phone
- UMTS

Exposure	Parameters
Exposure 1: 1,950 MHz Exposure duration: intermittent, 6 min on/2 h off, for 24, 44, or 24 + 44 h	SAR: 2.2 W/kg

Exposure 1

Main characteristics

Frequency	1,950 MHz
Type	electromagnetic field
Charakteristic	guided field
Exposure duration	intermittent, 6 min on/2 h off, for 24, 44, or 24 + 44 h

Modulation

Modulation type	cf. additional info
Additional info	UMTS 3GPP standard (FDD mode)

Exposure setup

Exposure source	TEM cell [Zeni et al., 2003]
Chamber	The TEM cell was placed vertically inside an incubator equipped with air circulation systems.
Setup	Two 25-ml Pyrex flasks filled with 10 ml of whole blood culture were placed 1 cm from each other on each side of the septum over a 1.5-mm thick Plexiglas shelf and radiated from the bottom.
Sham exposure	A sham exposure was conducted.
Additional info	Several independent temperature measurements were carried out in dummy cultures (flasks filled with culture medium) applying constant input power of 6 W for 6 min. A temperature increase of 0.67 ± 0.35 °C was measured, but the "off" period (2 h) was long enough to restore the initial conditions.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2.2 W/kg	-	calculated	-	-

Measurement and calculation details

Power was checked at different points of the feeding line throughout the exposure. The electric field and SAR distributions were determined using FDTD computational dosimetry considering four different materials. The electromagnetic characteristics for glass, plastic material, and blood were obtained from literature, while culture permittivity and conductivity were measured.

Reference articles

Zeni O et al. (2003): Lack of genotoxic effects (micronucleus induction) in human lymphocytes exposed in vitro to 900 MHz electromagnetic fields

Exposed system:

intact cell/cell culture

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: genotoxic effects during different cell cycle stages (cytokinesis block micronucleus assay; alkaline comet assay to detect primary DNA damage)
cell viability/cell division/proliferation: cell proliferation (cytokinesis block proliferation index; binucleate cell index); cell cycle kinetics

Investigated system:

DNA/RNA
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The data showed that intermittent exposures in different stages of the cell cycle to the UMTS signal at SAR value of the current European safety limit do not induce genotoxic or cytotoxic effects in human lymphocytes.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Sannino A et al. (2014): Adaptive response in human blood lymphocytes exposed to non-ionizing radiofrequency fields: resistance to ionizing radiation-induced damage
Waldmann P et al. (2013): Influence of GSM Signals on Human Peripheral Lymphocytes: Study of Genotoxicity
Zeni O et al. (2012): Radiofrequency radiation at 1950 MHz (UMTS) does not affect key cellular endpoints in neuron-like PC12 cells
Zeni O et al. (2012): Induction of an adaptive response in human blood lymphocytes exposed to radiofrequency fields: Influence of the universal mobile telecommunication system (UMTS) signal and the specific absorption rate
Sannino A et al. (2011): Induction of adaptive response in human blood lymphocytes exposed to 900 MHz radiofrequency fields: Influence of cell cycle
Esmekaya MA et al. (2011): Mutagenic and morphologic impacts of 1.8 GHz radiofrequency radiation on human peripheral blood lymphocytes (hPBLs) and possible protective role of pre-treatment with Ginkgo biloba (EGb 761)
Hintzsche H et al. (2010): Micronucleus frequency in buccal mucosa cells of mobile phone users
Sannino A et al. (2009): Induction of adaptive response in human blood lymphocytes exposed to radiofrequency radiation
Schwarz C et al. (2008): Radiofrequency electromagnetic fields (UMTS, 1,950 MHz) induce genotoxic effects in vitro in human fibroblasts but not in lymphocytes
Manti L et al. (2008): Effects of modulated microwave radiation at cellular telephone frequency (1.95 GHz) on X-ray-induced chromosome aberrations in human lymphocytes in vitro
Ferreira AR et al. (2006): Ultra high frequency-electromagnetic field irradiation during pregnancy leads to an increase in erythrocytes micronuclei incidence in rat offspring
Sannino A et al. (2006): Evaluation of Cytotoxic and Genotoxic Effects in Human Peripheral Blood Leukocytes Following Exposure to 1950-MHz Modulated Signal