Effects of twenty-minute 3G mobile phone irradiation on event related potential components and early gamma synchronization in auditory oddball paradigm.

We investigated the potential effects of 20 min irradiation from a new generation Universal Mobile Telecommunication System (UMTS) 3G mobile phone on human event related potentials (ERPs) in an auditory oddball paradigm. In a double-blind task design, subjects were exposed to either genuine or sham irradiation in two separate sessions. Before and after irradiation subjects were presented with a random series of 50 ms tone burst (frequent standards: 1 kHz, P=0.8, rare deviants: 1.5 kHz, P=0.2) at a mean repetition rate of 1500 ms while electroencephalogram (EEG) was recorded. The subjects' task was to silently count the appearance of targets. The amplitude and latency of the N100, N200, P200 and P300 components for targets and standards were analyzed in 29 subjects. We found no significant effects of electromagnetic field (EMF) irradiation on the amplitude and latency of the above ERP components. In order to study possible effects of EMF on attentional processes, we applied a wavelet-based time-frequency method to analyze the early gamma component of brain responses to auditory stimuli. We found that the early evoked gamma activity was insensitive to UMTS RF exposition. Our results support the notion, that a single 20 min irradiation from new generation 3G mobile phones does not induce measurable changes in latency or amplitude of ERP components or in oscillatory gamma-band activity in an auditory oddball paradigm.

Occupational 50 Hz magnetic field exposure measurements among female sewing machine operators in Hungary.

Occupational magnetic field (MF) exposure is less thoroughly characterized in occupations typically held by women. Our objective was to characterize occupational 50 Hz MF personal exposure (PE) among female sewing machine operators. We measured the full shift PE of 51 seamstresses, who worked in two shifts (6-14 and 14-22 h) according to their normal work routine. Measurements were conducted using EMDEX PAL meters at chest level. The average duration of the measurement periods was 449 min (range 420-470). The average arithmetic mean exposure for all women was 0.76 microT (range 0.06-4.27). The average of maximum values was 4.30 microT (range 0.55-14.80). Women working with older sewing machines experienced higher exposure than women working on newer sewing machines. For women (n = 10) who operated sewing machines produced in 1990 or earlier, the average arithmetic mean exposure was 2.09 microT, and for women (n = 41) who operated sewing machines produced after 1990, the average arithmetic mean was 0.43 microT. We conclude that women working as sewing machine operators experience higher than average occupational MF exposure compared to other working women. Most important determinant of the women's personal MF exposure was the age of the sewing machine the women operated.

Influence on the mechanisms of generation of distortion product otoacoustic emissions of mobile phone exposure.

Mobile phones have become very commonly used throughout the world within a short period of time. Although there is no clear evidence to show harmful physiological effects of electromagnetic fields (EMF) at the levels used by mobile phones, there is widespread public concern that there may be potential for harm. Because mobile phones are usually held close to the ear, it is appropriate to study effects on hearing. In this study, the outer hair cell function of 15 subjects was assessed by DPOAE recording before and after a controlled EMF exposure. To increase the sensitivity of DPOAE recording to identify even small changes in hearing function, an inverse fast Fourier transform (IFFT) analysis and time-domain windowing was applied to separate the two generation mechanisms of DPOAE, the so-called place-fixed and wave-fixed mechanisms, in order to verify if EMF can affects the two DPOAE emission mechanisms. Statistical analysis of the data showed that 10 min of EMF exposure at the maximum power (2 W at 900 MHz or 1 W at 1800 MHz) does not induce any changes in either DPOAE generation mechanism.

Biological responses of tight junction to ionizing radiation and electromagnetic field expostion.

The tight junctions form and regulate the paracellular barrier in the intercellular spaces between epithelial and endothelial cells. They play important roles in the cellular and pathological processes, which follow exposure to radiation. Therefore, analysis of their changes upon different kind of irradiation may help to understand the basic events governing their function and give important information for the radiobiological research and clinical practice as well. The immunohistochemical data on the distribution of occludin presented here demonstrate the breakdown of tight junctions in Madin Darby kidney cells exposed to ionizing irradiation and show, on the other hand that magnetic field exposures upon 100 microT leave the occludin staining pattern intact.

[In vitro and in vivo study of electromagnetic compatibility of cellular phones and pacemakers]. / Rádiótelefonok és pacemakerek elektromágneses kompatibilitásának vizsgálata.

Electromagnetic compatibility (EMC) of cellular phones and pacemakers (PM) was examined in four different cellular phone system (NMT, GSM, RLL, DCS 1800 MHz) and in fifteen different PM type in-vitro and in-vivo in humans. After more than 1100 in-vitro and 130 in-vivo tests we concluded, that the electromagnetic immunity of the PMs which are implanted in Hungary is suitable with only few exceptions. The highest rate of EMC problems was observed with NMT 450 MHz cellular phones (10.5%-63%). There was no EMC disturbance observed with GSM and DCS 1800 MHz cellular phones. There was only one case when clinically significant symptom was noticed with only one PM type and with NMT system cellular phone when the distance of cellular phone was 3-4 cms, and the power was maximal. There was not any EMC disturbance observed with none of the cellular phone systems during normal talking and when the distance of the PM and cellular phone was more than 20 cms. Our study supports guidelines which suggest that PM patients should contact their physicians when using cellular phones and cellular phones and PMs should not get closer than 20 cms.

Effect of sinusoidal 50 Hz magnetic field on the testosterone production of mouse primary Leydig cell culture.

This study evaluated the effect of sinusoidal 50 Hz magnetic field on the basal and human chorionic gonadotropin (hCG)-stimulated testosterone (T) production of 48-h mouse Leydig cell culture. The luteinizing hormone (LH) analog hCG was used to check the T response of the controls and to evaluate the possible effect of the applied magnetic field on the steroidogenic capacity of the exposed cells. Leydig cells were obtained from the testes of 35- to 45-g CFLP mice and isolated by mechanical dissociation without enzyme treatment. The cell cultures were exposed to sinusoidal 50 Hz 100 microT (root mean square) AC magnetic field during the entire time of a 48-h incubation. Testosterone content of the culture media was measured by radioimmunoassay. In cultures exposed to the magnetic field, a marked increase of basal T production was found (P < .05), compared with the unexposed controls, whereas no significant difference was seen between the exposed or unexposed cultures in the presence of maximally stimulating concentration of hCG. These findings demonstrate that sinusoidal 50 Hz 100 microT magnetic fields are able to stimulate the basal T production of primary mouse Leydig cell culture, leaving the steroidogenic responsiveness to hCG unaltered.

Urinary 6-sulphatoxymelatonin excretion is increased in rats after 24 hours of exposure to vertical 50 Hz, 100 microT magnetic field.

The effect of exposure to a 50 Hz, vertical magnetic field on the excretion of urinary 6-sulphatoxymelatonin (aMT6s) of rats was studied in a self-controlled experiment. Ten male Wistar rats were kept under 9:15 h light: dark conditions in metabolic cages. The rats were exposed to 1.0 or 100 microT flux density for 24 h. The excretion of aMT6s, which is the primary metabolite of melatonin in the urine, did not show a statistically significant decrease, as measured by 125I radioimmunoassay, during or after magnetic field exposure of rats to either flux density. At 100 microT flux density, the increase of aMT6s excretion on the day after exposure was statistically significant (P < .02), compared with the value under exposure, but was not significant compared with the baseline values before exposure.

Qualitative enzyme histochemistry and microanalysis reveals changes in ultrastructural distribution of calcium and calcium-activated ATPases after microwave irradiation of the medial habenula.

The localization of calcium and calcium-activated ATPases was investigated electron microscopically in the medial habenula of mice after whole body irradiation with modulated microwaves. In non-irradiated animals calcium-containing precipitates were seen in different subcellular compartments and were often localized on the luminal side of membranes of synaptic vesicles in nerve terminals. At 1 h after 16-Hz modulated microwave irradiation, the number of synaptic vesicles containing calcium precipitates decreased, and reaction products appeared at new locations: in the synaptic clefts and on non-synaptic surfaces of the neuronal plasma membrane. This modified calcium distribution remained unchanged for 24 h following irradiation. Calcium-activated "ecto"-localized ATPase was detected as a punctuated-linear distribution of the reaction product outlining whole areas of glial and neuronal plasma membrane in the habenula of control animals. This pattern did not change on microwave irradiation. However, a quercetin-sensitive "endo"-localized Ca(2+)-ATPase activity appeared in some nerve terminals 24 h after irradiation. Thus, microwave irradiation can influence neuronal calcium homeostasis by inducing Ca2+ redistribution across the plasma membrane and by modifying Ca(2+)-ATPase activity. However, no direct correlation between these effects could be demonstrated by the present study.

Effect on the immune system of mice exposed chronically to 50 Hz amplitude-modulated 2.45 GHz microwaves.

The effect of continuous (CW; 2.45 GHz carrier frequency) or amplitude-modulated (AM; 50 Hz square wave) microwave radiation on the immune response was tested. CW exposures (6 days, 3 h/day) induced elevations of the number of antibody-producing cells in the spleen of male Balb/c mice (+37%). AM microwave exposure induced elevation of the spleen index (+15%) and antibody-producing cell number (+55%) in the spleen of male mice. No changes were observed in female mice. It is concluded that both types of exposure conditions induced moderate elevation of antibody production only in male mice.

Effect of continuous-wave and amplitude-modulated 2.45 GHz microwave radiation on the liver and brain aminoacyl-transfer RNA synthetases of in utero exposed mice.

Investigations have been carried out concerning the effects of microwave (MW) exposure on the aminoacyl-transfer ribonucleic acid (tRNA) synthetase of the progeny of females that were exposed during their entire period of gestation (19 days). The changes caused by continuous-wave (CW) and amplitude-modulated (AM) MW radiation have been compared. CFLP mice were exposed to MW radiation for 100 min each day in an anechoic room. The MW frequency was 2.45 GHz, and the amplitude modulation had a 50 Hz rectangular waveform (on/off ratio, 50/50%). The average power density exposure was 3 mW/cm2, and the whole body specific absorption rate (SAR) was 4.23 +/- 0.63 W/kg. The weight and mortality of the progeny were followed until postnatal day 24. Aminoacyl-tRNA synthetase enzymes and tRNA from the brains and livers of the offspring (461 exposed, 487 control) were isolated. The aminoacyl-tRNA synthetase activities were determined. The postnatal increase of body weight and organ weight was not influenced by the prenatal MW radiation. The activity of enzyme isolated from the brain showed a significant decrease after CW MW exposure, but the changes were not significant after 50 Hz AM MW exposure. The activity of the enzyme isolated from liver increased under CW and 50 Hz modulated MW.

A complex cerebrovascular screening system (CERBERUS).

Stroke is unique among neurological diseases since it has a high incidence rate, severe burden of illness, high economic cost, and it may be preventable [1]. Described here is a system for screening the cerebral and vascular status of individuals to detect the initial stages of vascular disorders. The computer based polygraphic system (CERBERUS) questions subjects about risk factors, stresses, neurologic symptoms and monitors impedance pulse waves of the head and extremities, EEG, and ECG. The system has been tested in 691 cases. Doppler control studies were carried out on approximately 300 of these cases. Additional somatic measures and psychological tests related to stroke risk factors were carried out for wide biological basis of possible correlation of CERBERUS data base. The high incidence of cerebrovascular disturbance was established by CERBERUS data, further confirmed by additional data gathered, and moreover was compared by traditional medical records. The polygraphic system is more sensitive at detecting physiological asymmetries of blood flow than even a Doppler measurements. This suggests that it may be a significantly improved means for the differential diagnosis of neurological disease and the screening of subjects for arteriosclerosis, transient ischemic attack and stroke prevention to be offered at the lowest level of medical service.

Sinusoidal 50 Hz, 500 microT magnetic field has no acute effect on urinary 6-sulphatoxymelatonin in Wistar rats.

The effect of a 50 Hz, vertical magnetic field on the excretion of urinary 6-sulphatoxymelatonin (aMT6s) of male and female Wistar rats was studied in a self-controlled experiment. Twenty rats were kept in metabolic cages under 9:15 h light:dark conditions. The urine of the animals was collected twice per day for 5 consecutive days. The concentration of aMT6s in the rat urine was measured by 125I radioimmunoassay. The rats were exposed to 5 and 500 microT flux density for 24 h. The excretion of urinary aMT6s did not show significant changes during or after magnetic field exposure.

Simultaneous response of brain electrical activity (EEG) and cerebral circulation (REG) to microwave exposure in rats.

The correlations between physiological modalities in microwave field-activated systemic or localized regulatory mechanisms with changes in the central nervous system (CNS) seem not to be identical. These problems are important because of the increased number of radiating appliances, e.g. portable radios and mobile telephones. In two series of experiments on anaesthetized rats (N = 40) (i) before and after 10 min, whole body exposures to 2.45 GHz CW microwaves, and (ii) during 30 min exposures to 4 GHz amplitude modulated (AM, 16 Hz) microwaves, the effects on the CNS were observed simultaneously with those on the cardiovascular system by quantitative polygraphic measurement. In acute experiments on rats, electroencephalograms (EEG), rheoencephalograms (REG) as an index of cerebral blood flow (CBF), brain tissue DC impedance and temperature and ECG were recorded simultaneously. The total power of EEG spectra increased after whole body 30 mW/cm2 2.45 GHz CW exposure for 10 min. No changes occurred at 10 mW/cm2. The CBF increased after 10 mW/cm2 exposure. The power of EEG delta (0.5-4 Hz) waves was increased by thermal level of brain localized 4 GHz CW exposure at 42 mW/g specific absorption rate (SAR) simultaneously with the REG amplitude as an index of cerebral blood flow. Amplitude modulation at 16 Hz and 8.4 mW/g SAR was associated with increased power of EEG beta (14.5-30 Hz) waves but changes in the CBF were not observed. CW radiation at 8.4 mW/g increased the cerebral blood flow, but did not change EEG spectra.

Effects of modulated microwave and X-ray irradiation on the activity and distribution of Ca(2+)-ATPase in small intestine epithelial cells.

The distribution and activity of Ca(2+)-ATPase were investigated by histochemical methods in small intestine epithelial cells of mice following total body 2450 MHz low frequency (16 Hz) microwave and X-ray irradiation. In the control animals, enzyme activities were found in the brush border and on lateral membranes, including junctional areas of the cells. The enzyme activity of lateral membranes was inhibited by quercetin, a specific inhibitor of Ca(2+)-ATPase. Immediately after square modulated (16 Hz) 2450 MHz microwave irradiation at 1 mW/cm2 power densities, we observed a decreased activity of Ca(2+)-ATPase on the lateral membrane regions. The X-ray irradiation (1 Gy) induced a similar decrease of Ca(2+)-ATPase activity which was reversible within 24 hours. "5 Gy" doses resulted in a decrease of enzyme activities on both apical and lateral membrane areas persisting up to 24 hours following irradiation.

Effects of modulated and continuous microwave irradiation on pyroantimonate precipitable calcium content in junctional complex of mouse small intestine.

The pyroantimonate precipitable calcium content of intestinal epithelial cells was investigated in mice following total body irradiation with 2450 MHz continuous and low frequency (16 Hz) square modulated waves. In the control animals the reaction products appeared in the intercellular space of adjacent cells including intermediate junctions and desmosomes and were absent in the area of tight junctions. Immediately after low frequency modulated microwave irradiation at 0.5 and 1mW/cm2 power densities, a rapid distribution of pyroantimonate precipitable calcium content was observed. The pyroantimonate deposits were located on the cytoplasmic side of lateral membrane, in the area of junctional complex, including tight junction, and in other parts of lateral plasma membrane. These changes were reversible and 24 hours after the irradiation the distribution of pyroantimonate deposits was similar to the control. Continuous waves with same energy not altered the distribution of precipitable calcium. We conclude the low frequency modulated microwave irradiation can modify the calcium distribution without heat effects.

Effects of modulated and continuous microwave irradiation on the morphology and cell surface negative charge of 3T3 fibroblasts.

Mouse embryo 3T3 cells were irradiated with 2450 MHz continuous and low frequency (16 Hz) square modulated waves of absorbed energy ranging from 0.0024 to 2.4 mW/g. The low frequency modulated microwave irradiation yielded more morphological cell changes than did the continuous microwave fields of the same intensity. The amount of free negative charges (cationized ferritin binding) on cell surfaces decreased following irradiation by modulated waves but remained unchanged under the effect of a continuous field of the same dose. Modulated waves of 0.024 mW/g dose increased the ruffling activity of the cells, and caused ultrastructural alteration in the cytoplasm. Similar effects were experienced by continuous waves at higher (0.24 and 2.4 mW/g) doses.