A. Bitz

No effects of GSM-modulated 900 MHz electromagnetic fields on survival rate and spontaneous development of lymphoma in female AKR/J mice.

BackgroundSeveral reports indicated that non-thermal electromagnetic radiation such as from mobile phones and base stations may promote cancer. Therefore, it was investigated experimentally, whether 900 MHz electromagnetic field exposure influences lymphoma development in a mouse strain that is genetically predisposed to this disease. The AKR/J mice genome carries the AK-virus, which leads within one year to spontaneous development of thymic lymphoblastic lymphoma.Methods320 unrestrained female mice were sham-exposed or exposed (each n = 160 animals) to GSM like 900 MHz electromagnetic fields for 24 hours per day, 7 days per week, at an average whole body specific absorption rate (SAR) value of 0.4 W/kg. Animals were visually checked daily and were weighed and palpated weekly. Starting with an age of 6 months, blood samples were taken monthly from the tail. Animals with signs of disease or with an age of about 46 weeks were sacrificed and a gross necropsy was performed.ResultsElectromagnetic field exposure had a significant effect on body weight gain, with higher values in exposed than in sham-exposed animals. However, survival rate and lymphoma incidence did not differ between exposed and sham-exposed mice.ConclusionThese data do not support the hypothesis that exposure to 900 MHz electromagnetic fields is a significant risk factor for developing lymphoma in a genetically predisposed species, even at a relatively high exposure level.

Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus)

Abstract:u2002 In three experiments, adult male Djungarian hamsters (Phodopus sungorus) were exposed 24u2003hr/day for 60u2003days to radio frequency electromagnetic fields (RF‐EMF) at 383, 900, and 1800u2003MHz, modulated according to the TETRA (383u2003MHz) and GSM standards (900 and 1800u2003MHz), respectively. A radial waveguide system ensured a well defined and uniform exposure at whole‐body averaged specific absorption rates of 80u2003mW/kg, which is equal to the upper limit of whole‐body exposure of the general population in Germany and other countries. For each experiment, using two identical waveguides, hamsters were exposed (nu2003=u2003120) and sham‐exposed (nu2003=u2003120) in a blind fashion. In all experiments, pineal and serum melatonin levels as well as the weights of testes, brain, kidneys, and liver were not affected. At 383u2003MHz, exposure resulted in a significant transient increase in body weight up to 4%, while at 900u2003MHz this body weight increase was more pronounced (up to 6%) and not transient. At 1800u2003MHz, no effect on body weight was seen. The results corroborate earlier findings which have shown no effects of RF‐EMF on melatonin levels in vivo and in vitro. The data are in accordance with the hypothesis that absorbed RF energy may result in metabolic changes which eventually cause body weight increases in exposed animals. The data support the notion that metabolic effects of RF‐EMFs need to be investigated in more detail in future studies.

Electromagnetic Field Effect or Simply Stress? Effects of UMTS Exposure on Hippocampal Longterm Plasticity in the Context of Procedure Related Hormone Release

Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded.

1800 MHz electromagnetic field effects on melatonin release from isolated pineal glands

Abstract:u2002 Isolated pineal glands of Djungarian hamsters (Phodopus sungorus) were continuously perifused by Krebs–Ringer buffer, stimulated with the beta‐adrenergic receptor agonist isoproterenol to induce melatonin synthesis, and exposed for 7u2003hr to a 1800u2003MHz continuous wave (CW) or pulsed GSM (Global System for Mobile Communications)‐modulated electromagnetic signal at specific absorption rate (SAR) rates of 8, 80, 800, and 2700u2003mW/kg. Experiments were performed in a blind fashion. Perifusate samples were collected every hour, and melatonin concentrations were measured by a specific radioimmunoassay. Both types of signal significantly enhanced melatonin release at 800u2003mW/kg SAR, while at 2700u2003mW/kg SAR, melatonin levels were elevated in the CW, but suppressed in the GSM‐exposed pineal glands. As a temperature rise of approximately 1.2°C was measured at 2700u2003mW/kg SAR, effects at this level are thermal. With regard to radiofrequency electromagnetic fields, the data do not support the ‘melatonin hypothesis,’ according to which nonthermal exposure suppresses melatonin synthesis.

New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings

The development and analysis of three waveguides for the exposure of small biological in vitro samples to mobile communication signals at 900u2009MHz (GSM, Global System for Mobile Communications), 1.8u2009GHz (GSM), and 2u2009GHz (UMTS, Universal Mobile Telecommunications System) is presented. The waveguides were based on a fin-line concept and the chamber containing the samples bathed in extracellular solution was placed onto two fins with a slot in between, where the exposure field concentrates. Measures were taken to allow for patch clamp recordings during radiofrequency (RF) exposure. The necessary power for the achievement of the maximum desired specific absorption rate (SAR) of 20u2009W/kg (average over the mass of the solution) was approximately P(in) u2009=u200950u2009mW, P(in) u2009=u200919u2009mW, and P(in) u2009=u200918u2009mW for the 900u2009MHz, 1800u2009MHz, and 2u2009GHz devices, respectively. At 20u2009W/kg, a slight RF-induced temperature elevation in the solution of no more than 0.3u2009°C was detected, while no thermal offsets due to the electromagnetic exposure could be detected at the lower SAR settings (2, 0.2, and 0.02u2009W/kg). A deviation of 10% from the intended solution volume yielded a calculated SAR deviation of 8% from the desired value. A maximum ±10% variation in the local SAR could occur when the position of the patch clamp electrode was altered within the area where the cells to be investigated were located.

RF-exposure system for the uniform exposure of a large number of biological samples

This paper gives an introduction to a completely shielded RF-exposure system designed on the basis of a radial waveguide that enables a well defined highly uniform exposure of a large number of biological samples. For easy handling of the biological samples, special openings allow the insertion and removal of the samples without any actuation of closures and without any decrease of the shielding effectiveness.

Combination of the hybrid/sup [2]/-method and the FDTD-method for solution of boundary value problems with electrically large and high-resolution bodies

For risk assessment of mobile communication systems, the determination of safety distances of base station antennas for occupational and public exposure is an application of increasing interest. The underlying problem covers the analysis of antenna parameters, computation of near and far field distributions of base station antennas including the effects of reflection and diffraction at objects close to and far away from the antenna (e.g. buildings and vehicles), and the computation of the electromagnetic field distribution inside a human body. For the latter the Finite Difference TimeDomain (FDTD) Method is commonly used in combination with high-resolution human body models. Due to the character of the FDTD as a local numerical method, however, the FDTD is not suitable for problems with large dimensions. Especially for the investigation of scattering problems involving base station antennas mounted on buildings, the use of the FDTD is not efficient or even impossible. Therefore, in this work a combination of the Hybrid(*)-Method and the FDTD-Method is performed. The Hybrid(2)-Method, introduced first in [ 11, is a very powerful method for solving complex electromagnetic problems consisting of arbitrarily shaped and inhomogeneous objects and electrically large structures. It is successfully applied to analyze, for example, base station antennas of mobile communication systems embedded in real environments, e.g. mounted on multi-layered walls near building corners and windows [2, 3,4,5].

900 MHZ Electromagnetic Fields: Exposure Parameters and Effects on Djungarian Hamsters

It is generally accepted that radio frequency (RF) electromagnetic fields (EMF) can result in adverse effects if the intensities of the fields are high enough to increase the temperature of the biological target above the level of thermal noise. The mechanisms by which non-thermic EMF may have biological effects, however, are not yet understood. In the view of increasing public concerns about electromagnetic radiation (“electro-smog”) it is important to address this point, especially because of the steadily increasing use of mobile telephones and other electronic equipment working in the MHz to GHz range and operating with signal modulations in the frequency range of biological activities.