Sidorenko AV · 1999
Researchers used the nonlinear dynamics method together with the spectral correlation method to process animal electrocorticograms. They found that the nonlinear dynamics method may be used to analyze electrocorticograms in different functional states, confirmed by increased correlation dimensionality in animals exposed to microwaves or given strychnine. Correlation dimensionality serves as a numerical criterion for comparing dynamic states of the system.
Preece et al. · 1999
Thirty-six participants completed a randomized three-way crossover study with two training sessions and three test sessions. The only cognitive measure that changed was choice reaction time, which became faster, while word, number, picture recall and spatial memory were unchanged.
Morrissey JJ et al. · 1999
Researchers investigated the effects of a one-hour exposure of mice to a 1.6-GHz radiofrequency signal, either continuous wave or pulse-modulated at 11 Hz (IRIDIUM), on c-fos gene expression in the brain. C-fos expression was not significantly elevated until exposure levels exceeded six times the peak dose and 30 times the whole-body average dose relative to human cellular telephone exposure limits. The pattern of c-fos elevation in limbic cortex and subcortex areas was consistent with a stress response due to thermal perception and restraint, not a direct interaction of IRIDIUM energy with brain tissue.
Khudnitskii, SS, Moshkarev, EA, Fomenko, TV, · 1999
The authors studied the influence of ultrahigh frequency radiation from cellular phones on the functional state of the central nervous and cardiovascular systems and on local temperature changes in users. The head area near the phone antenna appeared to be under the most intensive heating, and ultrahigh frequency radiation induced significant changes in local temperature and physiologic parameters of the central nervous and cardiovascular systems.
Johnson EH, Chima SC, Muirhead DE · 1999
Researchers examined an adult squirrel monkey with a history of long-term exposure to microwave radiation that had a malignant tumor in the right cerebral cortex. Microscopy showed sheets of moderate-sized cells with clear cytoplasm and central nuclei, resembling an oligodendroglioma, with malignant features including nuclear pleomorphism, mitotic figures, and necrosis. Immunohistochemical analysis supported a neuronal origin with positivity for neurofilament proteins and neuron-specific enolase, while vimentin and glial fibrillary acidic protein were negative except in reactive astrocytes. The tumor showed strong positivity for Ki-67 antigen and p53 oncoprotein, indicating aggressive malignant nature, and was diagnosed as a cerebral primitive neuroectodermal tumor.
Hardell et al. · 1999
Researchers conducted a case-control study with 209 brain tumour cases and 425 controls in Sweden. Overall cellular telephone use yielded an odds ratio of 0.98 with a 95% confidence interval. Separate analyses for the digital GSM system and the analogue NMT system gave odds ratios of 0.97 and 0.94 respectively. A non-significantly increased risk was found for tumours in the temporal or occipital lobe on the same side as phone use. The increased risk was only seen for use of the NMT system.
Dreyer NA, Loughlin JE, Rothman KJ · 1999
The initial protocol called for continuing surveillance for mortality. Access to data beyond 1 year was blocked by a class-action lawsuit challenging the legality of monitoring product safety through record linkage.
Van Leeuwen GM et al. · 1999
Researchers evaluated 3D temperature rise in a realistic head model induced by a mobile phone. The power distributions had a maximum averaged SAR over a 10 g volume of approximately 1.6 W kg(-1). Simulations showed a maximum brain temperature rise of 0.11 degrees C for a 0.25 W antenna with indefinite exposure, and the authors noted that temperature rises are far too small to have lasting effects.
Paul Raj R, Behari J, Rao AR · 1999
The effect of exposing rats to amplitude-modulated radiofrequency radiation (112 MHz modulated to 16 Hz) during development and growth was examined. Wistar rats 35 days old exposed at 1.0 mW/cm2 (SAR 0.75 W/kg) for 35 days showed enhanced ornithine decarboxylase activity and Ca2+ efflux in brain.
Kemerov, S, Marinkev, M, Getova, D · 1999
Researchers exposed 24 Wistar rats to low-intensity electromagnetic fields in the meter, decimeter, and centimeter ranges to compare behavioral effects across those ranges. The rats were irradiated on the head area at a power density of 10 mW/cm2, and conditioned and non-conditioned responses along with spontaneous motor activity were studied using a conventional shuttle box. Exposure to EMFs across all three ranges was associated with slowing of conditioned response formation, with the effect most clearly marked in rats exposed to meter EMFs, while effects of centimeter EMFs were delayed in time. The behavioral effects were mild at athermal dosages and the animals adapted easily to exposure conditions.
Borbely et al. · 1999
Researchers exposed healthy young subjects during an entire night-time sleep episode to a 900 MHz electromagnetic field at a maximum specific absorption rate of 1 W/kg. The exposure schedule consisted of alternating 15-min on-15-min off intervals. Compared with a control night with sham exposure, the amount of waking after sleep onset was reduced from 18 to 12 min, and EEG spectral power in non-rapid eye movement sleep was increased. The researchers concluded that pulsed high-frequency EMF in the range of radiotelephones may promote sleep and modify the sleep EEG.
Schonborn F, Burkhardt M, Kuster N · 1998
In order to investigate the differences in absorption between adults and children due to their differing anatomies, simulations were performed using head phantoms based on MRI scans of an adult and two children aged 3 and 7 years. Ten different tissue types were distinguished and all simulations were performed using a commercial code based on the finite integration technique. The differences in absorption were investigated for the frequencies of 900 MHz and 1,800 MHz using 0.45 lambda dipoles instead of actual mobile phones. The results revealed no significant differences in the absorption of electromagnetic radiation in the near field of sources between adults and children.
Malyapa RS et al. · 1998
Researchers exposed male Sprague-Dawley rats to 2450 MHz continuous-wave microwaves for two hours at 1.2 W/kg specific absorption rate. No significant differences in DNA damage were found between sham-exposed and irradiated rats in either the cerebral cortex or hippocampus, regardless of euthanasia method. Rats euthanized by CO2 asphyxia showed more intrinsic DNA damage and greater experiment-to-experiment variation than those euthanized by guillotine. The authors concluded that guillotine euthanasia is the most appropriate method for DNA damage studies. The study did not confirm previous reports of DNA damage from 2450 MHz microwave exposure.
Freude, G, Ullsperger, P, Eggert ,S, Ruppe, I · 1998
Researchers studied the influence of electromagnetic fields emitted by cellular phones on preparatory slow brain potentials in healthy male subjects using two experimental tasks. Both tasks were performed with and without EMF exposure in counterbalanced order. Subjects' performance did not differ between exposure conditions, but EMF exposure significantly decreased slow brain potentials at central and temporo-parieto-occipital regions during the visual monitoring task and did not affect the Bereitschaftspotential in the finger movement task.
Eulitz, C, Ullsperger, P, Freude, G, Elbert ,T · 1998
The study aimed to investigate how mobile phones modulate response patterns of human brain activity. The researchers found that pulsed high-frequency electromagnetic fields from mobile phones alter induced but not evoked brain activity in higher frequency bands during processing of task-relevant target stimuli, with no effect for irrelevant standard stimuli. The authors suggest that PEMF exposure may provide a means to systematically alter pattern fluctuations in neural mass activity.
Walters TJ et al. · 1998
Researchers measured hypothalamic, cortical, tympanic, and rectal temperatures in rats exposed to 2.06 GHz microwave radiation at two power densities. The high-power density was 1700 mW/cm² with specific absorption rates of 1224 W/kg in hypothalamus and 493 W/kg in cortex, while the low-power density was 170 mW/cm² with SARs of 122.4 W/kg and 49.3 W/kg. During high-power exposure, the hypothalamic temperature rose significantly faster than cortical or rectal temperatures, whereas low-power exposure produced more uniform heating. For comparison, warm-water immersion produced uniform heating, while warm ambient exposure and exercise maintained the pre-existing temperature gradient between hypothalamus and cortex.
Grigor'ev IuG, Stepanov VS · 1998
Researchers investigated how prior low-level electromagnetic field exposure affects memory formation (imprinting) in chicks. EMF at power densities from 0.4 to 10 mW/cm2 was found to potentially influence the forming of memory (imprinting). The study showed the possibility of EMF-modulated information being fixed in the embryonic brain during the natal period and conserved after birth.
Behari J, Kunjilwar KK, and Pyne S · 1998
Researchers studied the effect of low-level amplitude-modulated radiofrequency radiation on Na+–K+-ATPase activity in the brains of developing male Wistar rats aged 23 days. Rats were exposed to carrier wave frequencies of 147 MHz and its sub-harmonic frequencies 73.5 and 36.75 MHz, amplitude modulated at 16 and 76 Hz, for 30–35 days at 3 hours per day. Na+–K+-ATPase activity increased by around 19–20% in rats exposed with amplitude modulation at 16 Hz, and by around 15–16% in rats exposed with amplitude modulation at 76 Hz, compared to controls. The researchers concluded that the effect on Na+–K+-ATPase activity was insensitive to the carrier wave frequencies under investigation.
Salford LG, Brun A, Persson BRR · 1997
Researchers used Fischer 344 rats of both sexes with implanted glioma cells (RG2 and N32) in a matched-pair design. Starting on day 5 after inoculation, rats were exposed for 7 hours a day, 5 days a week for 2–3 weeks to 915 MHz continuous or pulse-modulated microwaves. The study found no significant difference in tumour size between exposed and control animals. Tumour size was estimated as the volume of an ellipsoid after histopathological examination of all brains.
Schilling, CJ · 1997
Persson BRR, Salford LG, Brun A · 1997
Researchers studied blood-brain barrier permeability in Fischer 344 rats of both sexes exposed to radio frequency electromagnetic fields. The exposure used 915 MHz microwaves delivered as either pulse-modulated or continuous wave signals. The rate of pathological leakage rose from 0.17 in controls to 0.39 across all exposed rats, a highly significant difference. Continuous wave exposure produced a higher rate of pathological rats (0.50 ± 0.07) than pulse-modulated exposure (0.35 ± 0.03), and that difference was also statistically significant.
Vorobyov VV, Galchenko AA, Kukushkin NI, Akoev IG · 1997
Researchers studied averaged EEG frequency spectra in eight unanesthetized adult male rats with chronically implanted electrodes in symmetrical somesthetic areas during intermittent exposure to a weak 945 MHz microwave field amplitude-modulated at 4 Hz. Hemispheric asymmetry showed power decreases in the 1.5-3 Hz range on the left and in the 10-14 and 20-30 Hz ranges on the right hemisphere. No differences between control and exposure were found in averaged spectra over 10 or 1 minute periods. However, significant elevations of EEG asymmetry in the 10-14 Hz range occurred during the first 20 seconds after most microwave field onsets when spectra were averaged every 10 seconds.
Rojavin MA, Ziskin MC · 1997
Researchers injected BALB/c mice with ketamine 80 mg/kg or chloral hydrate 450 mg/kg and exposed them to 61.22 GHz millimeter waves at 420 W/kg peak specific absorption rate for 15 minutes. Millimeter wave exposure increased anesthesia duration by about 50% compared to sham exposure, which had no effect.
Pu, JS, Chen, J, Yang, YH, Bai, YQ · 1997
Mason PA et al. · 1997
Researchers measured extracellular amino acid concentrations in the hypothalamus and caudate nucleus of rats using in vivo microdialysis before and during exposure to RFR. Rats were exposed to 5.02 GHz radiation (10 microseconds pulse width, 1000 pulses/s) for 40 minutes while brain temperatures were maintained at approximately 41.2 and 41.7 degrees C. Aspartic acid, serine, and glycine concentrations increased significantly in both regions during exposure. Glutamic acid and glutamine changes were not statistically significant.
