Joachim Streckert

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 Radiofrequency Electromagnetic Fields (UMTS) on Reproduction and Development of Mice: A Multi-generation Study

Abstract Sommer, A. M., Grote, K., Reinhardt, T., Streckert, J., Hansen, V. and Lerchl, A. Effects of Radiofrequency Electromagnetic Fields (UMTS) on Reproduction and Development of Mice: A Multi-generation Study. Radiat. Res. 171, 89–95 (2009). Male and female mice (C57BL) were chronically exposed (life-long, 24 h/day) to mobile phone communication electromagnetic fields at approximately 1966 MHz (UMTS). Their development and fertility were monitored over four generations by investigating histological, physiological, reproductive and behavioral functions. The mean whole-body SARs, calculated for adult animals at the time of mating, were 0 (sham), 0.08, 0.4 and 1.3 W/kg. Power densities were kept constant for each group (0, 1.35, 6.8 and 22 W/m2), resulting in varying SARs due to the different numbers of adults and pups over the course of the experiment. The experiment was done in a blind fashion. The results show no harmful effects of exposure on the fertility and development of the animals. The number and the development of pups were not affected by exposure. Some data, albeit without a clear dose–response relationship, indicate effects of exposure on food consumption that is in accordance with some data published previously. In summary, the results of this study do not indicate harmful effects of long-term exposure of mice to UMTS over several generations.

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

Abstract:  In three experiments, adult male Djungarian hamsters (Phodopus sungorus) were exposed 24 hr/day for 60 days to radio frequency electromagnetic fields (RF‐EMF) at 383, 900, and 1800 MHz, modulated according to the TETRA (383 MHz) and GSM standards (900 and 1800 MHz), respectively. A radial waveguide system ensured a well defined and uniform exposure at whole‐body averaged specific absorption rates of 80 mW/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 (n = 120) and sham‐exposed (n = 120) 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 383 MHz, exposure resulted in a significant transient increase in body weight up to 4%, while at 900 MHz this body weight increase was more pronounced (up to 6%) and not transient. At 1800 MHz, 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.

Lymphoma development in mice chronically exposed to UMTS-modulated radiofrequency electromagnetic fields.

Abstract Sommer, A. M., Bitz, A. K., Streckert, J., Hansen, V. W. and Lerchl, A. Lymphoma Development in Mice Chronically Exposed to UMTS-Modulated Radiofrequency Electromagnetic Fields. Radiat. Res. 168, 72–80 (2007). There are public concerns regarding possible carcinogenic or cancer-promoting effects of electromagnetic fields (EMFs) from mobile phones and base stations. The objective of the present study was to investigate whether chronic exposure to EMFs of the UMTS (Universal Mobile Telecommunication System) influences the development of lymphoma in a lymphoma animal model, the AKR/J mouse. Unrestrained mice were chronically sham-exposed (n = 160) or exposed (n = 160) in identical exposure systems (radial waveguides) to a generic UMTS test signal (24 h per day, 7 days per week, 0.4 W/kg SAR). Additionally, 30 animals were kept as cage controls. Animals were checked visually each day and were weighed and palpated weekly to detect swollen lymph nodes. Starting at the age of 6 months, blood samples were taken from the tail every 2 weeks to perform differential leukocyte counts and to measure the hematocrit. Visibly diseased animals or those older than 43 weeks were killed humanely, and tissue slices were examined for metastatic infiltrations and lymphoma type. The study was performed in a blinded way. Cage control animals had a significantly lower growth rate than those kept in the radial waveguides. The number of ill animals, the mean survival time, and the severity code of the disease did not differ between the experimental groups. Therefore, the data show no negative effects from exposure and corroborate earlier findings in AKR/J mice exposed to GSM EMF (Sommer et al., BMC Cancer 4, 77–90, 2004).

Effects of universal mobile telecommunications system (UMTS) electromagnetic fields on the blood-brain barrier in vitro

Abstract Franke, H., Streckert, J., Bitz, A., Goeke, J., Hansen, V., Ringelstein, E. B., Nattkämper, H., Galla, H-J. and Stögbauer, F. Effects of Universal Mobile Telecommunications System (UMTS) Electromagnetic Fields on the Blood-Brain Barrier In Vitro. Radiat. Res. 164, 258–269 (2005). The extensive use of mobile phone communication has raised public concerns about adverse health effects of radiofrequency (RF) electromagnetic fields (EMFs) in recent years. A central issue in this discussion is the question whether EMFs enhance the permeability of the blood-brain barrier (BBB). Here we report an investigation on the influence of a generic UMTS (Universal Mobile Telecommunications System) signal on barrier tightness, transport processes and the morphology of porcine brain microvascular endothelial cell cultures (PBEC) serving as an in vitro model of the BBB. An exposure device with integrated online monitoring system was developed for simultaneous exposure and measuring of transendothelial electrical resistance (TEER) to determine the tightness of the BBB. PBEC were exposed continuously for up to 84 h at an average electric-field strength of 3.4–34 V/m (maximum 1.8 W/kg) ensuring athermal conditions. We did not find any evidence of RF-field-induced disturbance of the function of the BBB. After and during exposure, the tightness of the BBB quantified by 14C-sucrose and serum albumin permeation as well as by TEER remained unchanged compared to sham-exposed cultures. Permeation of transporter substrates at the BBB as well as the localization and integrity of the tight-junction proteins occludin and ZO1 were not affected either.

Indication of cocarcinogenic potential of chronic UMTS-modulated radiofrequency exposure in an ethylnitrosourea mouse model

Purpose: To evaluate putative effects on tumour susceptibility in mice exposed to a UMTS (universal mobile telecommunications system) test signal for up to 24 months, commencing with embryo-fetal exposure. Material and methods: Animals were exposed to UMTS fields with intensities of 0, 4.8, and 48 W/m2, the low-dose group (4.8 W/m2) was subjected to additional prenatal ethylnitrosourea treatment (40 mg ENU/kg body weight). Results: The high-level UMTS exposure (48 W/m2), the sham exposure, and the cage control groups showed comparable tumour incidences in the protocol organs. In contrast, the ENU-treated group UMTS-exposed at 4.8 W/m2 displayed an enhanced lung tumour rate and an increased incidence of lung carcinomas as compared to the controls treated with ENU only. Furthermore, tumour multiplicity of the lung carcinomas was increased and the number of metastasising lung tumours was doubled in the ENU/UMTS group as compared to the ENU control group. Conclusion: This pilot study indicates a cocarcinogenic effect of lifelong UMTS exposure (4.8 W/m2) in female B6C3F1 descendants subjected to pretreatment with ethylnitrosourea.

RF exposure of biological systems in radial waveguides

Two radial waveguide exposure systems for multiple biological targets are described that were conceived, dimensioned, implemented, measured and dosimetrically analyzed. In the first case, a number of 120 hamsters was exposed with mobile communication signals at 383 and 900 MHz. The variation of the dissipated energy within the animals could be reduced to less than 30% though the objects were not restrained. Whole body specific absorption rates of 80 mW/kg were applied. The other system was used for exposing hamsters pineal glands in culture. The small size of the samples yields an even smaller variation of the exposure of 2.4%. This is a consequence of the excellent uniformity of the electromagnetic field distribution across the exposure region, which was achieved by a good rotational symmetry of the waveguide and a careful design of the feed antenna and the absorber/shortcut combination. The paper reports on the technical aspects of the RF exposure.

Membrane potential and currents of isolated heart muscle cells exposed to pulsed radio frequency fields

The influence of radio frequency (RF) fields of 180, 900, and 1800 MHz on the membrane potential, action potential, L-type Ca(2+) current and potassium currents of isolated ventricular myocytes was tested. The study is based on 90 guinea-pig myocytes and 20 rat myocytes. The fields were applied in rectangular waveguides (1800 MHz at 80, 480, 600, 720, or 880 mW/kg and 900 MHz, 250 mW/kg) or in a TEM-cell (180 MHz, 80 mW/kg and 900 MHz, 15 mW/kg). Fields of 1800 and 900 MHz were pulsed according to the GSM-standard of cellular phones. The specific absorption rates were determined from computer simulations of the electromagnetic fields inside the exposure devices by considering the structure of the physiological test arrangement. The electrical membrane parameters were measured by whole cell patch-clamp. None of the tested electrophysiological parameters was changed significantly by exposure to RF fields. Another physical stimulus, lowering the temperature from 36 degrees C to 24 degrees C, decreased the current amplitude almost 50% and shifted the voltage dependence of the steady state activation parameter d(infinity) and inactivation parameter f(infinity) of L-type Ca(2+) current by about 5 mV. However, at this lower temperature RF effects (900 MHz, 250 mW/kg; 1800 MHz, 480 mW/kg) on L-type Ca(2+) current were also not detected.

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:  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 7 hr to a 1800 MHz 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 2700 mW/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 800 mW/kg SAR, while at 2700 mW/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 2700 mW/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.