Medical/biological study (experimental study)

Cytogenetic studies in human blood lymphocytes exposed in vitro to 2.45 GHz or 8.2 GHz radiofrequency radiation med./bio.

By: Vijayalaxmi

Published in: Radiat Res 2006; 166 (3): 532-538

Aim of study (acc. to author)

To determine whether radiofrequency causes cytogenetic damage in human blood lymphocytes exposed in vitro.

Background/further details

Aliquots of the same blood samples from three male donors were used as positive controls (PHA-stimuated or to 1.5 Gy gamma radiation exposed cells).

Endpoint

genotoxicity/mutation: genotoxic effect (chromosome aberrations, micronuclei formation)
cell viability/cell division/proliferation: mitotic index

Exposure

- 2.45–8.2 GHz
- 2.45 GHz
- microwaves
- microwave pulses

Exposure	Parameters
Exposure 1: 2.45 GHz Modulation type: pulsed Exposure duration: continuous for 2 h	power density: 5 mW/cm² mean SAR: 2.135 W/kg mean (± 0.005 W/kg)
Exposure 2: 8.2 GHz Modulation type: pulsed Exposure duration: continuous for 2 h	power density: 10 mW/cm² mean SAR: 20.71 W/kg mean (± 0.08 W/kg)

General information

For positive control, samples were exposed to 1.5 Gy gamma radiation (¹³⁷Cs source) at a dose rate of 1.008 Gy/min.

Exposure 1

Main characteristics

Frequency	2.45 GHz
Type	electromagnetic field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	10 µs
Duty cycle	10 %
Repetition frequency	10 kHz

Exposure setup

Exposure source	horn antenna anechoic chamber rectangular, [Vijayalaxmi et al., 1997]
Distance between exposed object and exposure source	1.75 m
Chamber	The temperature in the anechoic room (18 x 9 x 9 ft) was maintained at 37 ± 1°C. The temperature in the incubator box was maintained at 36.9 ± 0.1°C by a flow of warm air through tubing immersed in a water bath and was monitored continuously using a Vitek probe.
Setup	T-25 tissue culture flasks containing 6 ml of whole blood were placed in an incubator box at a distance of 1.75 m from the opening of the antenna.
Sham exposure	A sham exposure was conducted.
Additional info	The cells were allowed to settle at the bottom of the culture flasks for 2 h before exposure.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	5 mW/cm²	mean	measured	-	-
SAR	2.135 W/kg	mean	calculated	-	± 0.005 W/kg

Additional parameter details

An FDTD analysis revealed that 90, 75, 50, 25, and 10% of the cells were exposed to SARs greater than 0.950, 1.395, 2.080, 2.730, and 3.520 W/kg, respectively.

Exposure 2

Main characteristics

Frequency	8.2 GHz
Type	electromagnetic field
Exposure duration	continuous for 2 h

Modulation

Modulation type	pulsed
Pulse width	8 ns
Duty cycle	0.04 %
Repetition frequency	50 kHz

Exposure setup

Exposure source	horn antenna anechoic chamber rectangular, [Natarajan et al., 2002]
Distance between exposed object and exposure source	1.46 m
Chamber	The anechoic room was 20 x 14 x 10 ft. The temperature in the incubator box was maintained at 37.4 ± 0.4°C by a flow of warm water from a compartment underneath and was monitored continuously using a Vitek probe.
Setup	T-25 tissue culture flasks containing 6 ml of diluted blood were placed in an incubator box at a distance of 1.46 m from the opening of the antenna.
Sham exposure	A sham exposure was conducted.
Additional info	In a second group, PHA (1%) was added to the diluted blood, and cultures were incubated at 37 ± 1°C for 24 h to stimulate the lymphocytes before exposure.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
power density	10 mW/cm²	mean	measured	-	-
SAR	20.71 W/kg	mean	calculated	-	± 0.08 W/kg

Additional parameter details

An FDTD analysis revealed that 90, 75, 50, 25, and 10% of the cells were exposed to SARs greater than 3.97, 9.56, 17.23, 25.93, and 38.81 W/kg, respectively.

Reference articles

Natarajan M et al. (2002): NF-kappaB DNA-binding activity after high peak power pulsed microwave (8.2 GHz) exposure of normal human monocytes
Vijayalaxmi et al. (1997): Proliferation and cytogenetic studies in human blood lymphocytes exposed in vitro to 2450 MHz radiofrequency radiation

Exposed system:

intact cell/cell culture

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: chromosome aberrations (examination of 200 lymphocytes); micronuclei formation
cell viability/cell division/proliferation: mitotic index (percentage of binucleate lymphocytes)

Investigated system:

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The levels of cytogenetic damage in radiofrequency irradiation exposed and sham-exposed lymphocytes were not significantly different. Also in the response of unstimulated lymphocytes and lymphocytes stimulated with PHA were no signficant differences when exposed to 8.2 GHz radiofrequency irradiation. In contrast, the positive control cells that had been subjected to 1.5 Gy gamma radiation exhibited significantly more cytogenetic damage than radiofrequency irradiation- and sham-exposed lymphocytes.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Air Force Office of Scientific Research (AFOSR), USA

Waldmann P et al. (2013): Influence of GSM Signals on Human Peripheral Lymphocytes: Study of Genotoxicity
Hintzsche H et al. (2012): 900 MHz radiation does not induce micronucleus formation in different cell types
Bourthoumieu S et al. (2010): Cytogenetic Studies in Human Cells Exposed In Vitro to GSM-900 MHz Radiofrequency Radiation Using R-Banded Karyotyping
Hintzsche H et al. (2010): Micronucleus frequency in buccal mucosa cells of mobile phone users
Tiwari R et al. (2008): Combinative Exposure Effect of Radio Frequency Signals from CDMA Mobile Phones and Aphidicolin on DNA Integrity
Hoyto A et al. (2008): Radiofrequency radiation does not significantly affect ornithine decarboxylase activity, proliferation, or caspase-3 activity of fibroblasts in different physiological conditions
Yadav AS et al. (2008): Increased frequency of micronucleated exfoliated cells among humans exposed in vivo to mobile telephone radiations
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Ferreira AR et al. (2006): Ultra high frequency-electromagnetic field irradiation during pregnancy leads to an increase in erythrocytes micronuclei incidence in rat offspring
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Vijayalaxmi et al. (2001): Micronuclei in the peripheral blood and bone marrow cells of rats exposed to 2450 MHz radiofrequency radiation
Vijayalaxmi et al. (2000): Primary DNA damage in human blood lymphocytes exposed in vitro to 2450 MHz radiofrequency radiation
Malyapa RS et al. (1998): DNA damage in rat brain cells after in vivo exposure to 2450 MHz electromagnetic radiation and various methods of euthanasia
Vijayalaxmi et al. (1997): Proliferation and cytogenetic studies in human blood lymphocytes exposed in vitro to 2450 MHz radiofrequency radiation
Lai H et al. (1995): Acute low-intensity microwave exposure increases DNA single-strand breaks in rat brain cells

Cytogenetic studies in human blood lymphocytes exposed in vitro to 2.45 GHz or 8.2 GHz radiofrequency radiation med./bio.

Aim of study (acc. to author)

Background/further details

Endpoint

Exposure

General information

Exposure 1

Main characteristics

Modulation

Exposure setup

Parameters

Additional parameter details

Exposure 2

Main characteristics

Modulation

Exposure setup

Parameters

Additional parameter details

Reference articles

Methods Endpoint/measurement parameters/methodology

Main outcome of study (acc. to author)

Study funded by

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