Unknown authors · 1993
Researchers conducted a telephone interview survey in November 1987 to assess depressive symptoms and headaches in relation to proximity to an alternating-current transmission line. Proximity was defined as residing on a property abutting the right-of-way or being able to see the towers from one's house or yard. Proximity was positively associated with depressive symptoms with an odds ratio of 2.8 (95% CI 1.6-5.1). The association was not explained by demographic variables associated with depression or by attitudes about power lines or other environmental issues. Nonmigraine headaches had a weaker association with proximity (odds ratio = 1.5, 95% CI 0.76-2.8) and self-reported migraine headaches exhibited no association (odds ratio = 0.99, 95% CI 0.29-3.4).
Ulashchik VS · 1993
The study aimed to investigate changes in drug pharmacokinetics and pharmacodynamics under the influence of microwaves of different ranges. Human and animal experiments were conducted to compare the effect of microwaves of different ranges on drug pharmacodynamics and pharmacokinetics. The results suggested that microwaves could potentiate and prolong the action of some drugs.
Kunjilwar KK, Behari J · 1993
Researchers exposed developing rats to amplitude-modulated radio frequency radiation at 147 MHz and its sub-harmonics for 30 to 35 days, three hours per day. A significant decrease in acetylcholine esterase activity was found in exposed rats compared to controls. The decrease in enzyme activity was independent of the carrier wave frequencies used. Short-term exposure did not significantly affect acetylcholine esterase activity.
Goldoni J, Durek M, Koren Z · 1993
Researchers examined two groups of workers occupationally exposed to microwaves and radiofrequency radiation and compared them with a control group. One group consisted of 49 radar operators from Zagreb Air Traffic Control who were examined twice over 18 months, and the other group comprised 46 workers at radio relay stations. A follow-up study found significant changes in haematological and biochemical parameters, electrical brain activity, and capillaroscopic and ophthalmological findings in the radar operators, and a cross-sectional analysis showed the highest rate of changes in general health status for that group.
Verma M, Dutta SK. · 1993
The study aimed to investigate microwave induced alteration in neuron specific enolase gene expression. Researchers exposed pNGE7 cells containing the neuron specific enolase gene to 915 MHz, 16 Hz AM radiation at SAR 0.05 mW/kg. Exposure resulted in elevation of neuron specific enolase, a diagnostic marker for neuron and lung cancer. Ion-exchange chromatography separated neuron specific enolase activity from non-neuronal enolase activity and showed altered expression of both.
Raslear TG, Akyel Y, Bates F, Belt M, Lu ST · 1993
Researchers studied the effects of high-peak-power pulsed microwaves on a time perception and discrimination task in rats. Time perception, response bias, and total trials did not change with power level. Dose-response effects were observed for discriminability, session time, and trial completions (null responses). Exposures used the TEMPO system with 80 nanosecond pulses exceeding 700 megawatts peak power, whole-body SAR of 0.072 W/kg, well below the 0.4 W/kg limit.
Pakhomov AG · 1993
Researchers investigated effects of 915 MHz pulsed microwave radiation with peak SAR 20-30 W/g on isolated frog nerve cords. Nerve heating did not exceed 2.2°C due to intense Ringer's solution perfusion. Irradiation during stimulation significantly decreased action potential amplitude and peak latency, while conventional heating increased amplitude, supporting a non-thermal mechanism.
Krylov IN, Iasnetsov VV, Dukhanin AS, Pal'tsev IuP · 1993
Researchers exposed rats to microwaves at 2375 MHz with a power density of 1 mW/cm2 and found that this induced retrograde amnesia. The study found roles for opioidergic, benzodiazepine, GABAergic, and cholinergic components in the memory-impairing effects of microwaves. Piracetam and oxiracetam each prevented the negative effects of microwaves on memory processes in the rats.
Field AS, Ginsburg K, Lin JC · 1993
Researchers studied the effects of pulsed microwaves on membrane input resistance and action potential interval statistics in spontaneously active ganglion neurons of land snails (Helix aspersa). Experiments were conducted at strictly constant temperature, so macroscopic heating was not responsible for any observed effects. Exposure significantly increased mean input resistance, while mean firing rate and mean input current were not affected. The net input current was found to be more variable in exposed neurons, though changes in interspike interval standard deviation and input current autocorrelation were not consistent across neurons.
Rusovan A, Kanje M, Mild KH · 1992
Researchers studied the effects of sinusoidal magnetic fields on regeneration of the rat sciatic nerve. The rats were exposed to a 0.1-mT magnetic field of various frequencies (50-2000 Hz) inside a pair of Helmholtz coils for various periods of time. Regeneration was measured by the pinch test or by immunocytochemical staining for neurofilaments 3, 4, or 6 days after the lesioning. Frequencies of 250, 500, and 1000 Hz significantly increased the regeneration distance, while higher (2000 Hz) and lower (50 Hz) frequencies had no effect. Maximal stimulation was obtained at 1000 Hz, and at this frequency the rate of regeneration was increased by 24%.
Unknown authors · 1992
The study used an ultrasensitive superconducting magnetometer to detect ferromagnetic material in various human brain tissues. High-resolution electron microscopy identified the minerals as belonging to the magnetite-maghemite family, with crystal morphologies resembling those produced by magnetotactic bacteria and fish. The measurements imply at least 5 million single-domain crystals per gram in most brain tissues and over 100 million per gram in the pia and dura.
Seaman RL, Beblo DA · 1992
Researchers presented single 1.25-GHz microwave pulses of 0.8- to 1.0-microseconds duration to four rats 100 ms before a startle-inducing acoustic stimulus. At a lower energy dose of 22-43 mJ/kg per pulse, the mean startle latency was longer and the mean amplitude was smaller compared to control responses to acoustic stimuli alone. At a higher energy dose of 59-107 mJ/kg per pulse, the mean latency and amplitude were not statistically different from controls.
Bolshakov MA, Alekseev SI · 1992
Researchers recorded spontaneous electrical activity and ionic currents of Lymnea stagnalis neurons during exposure to a 900-MHz field using modified microelectrode and voltage-clamp techniques. When subjected to pulsed waves, rapid burst-like changes in the firing rate of neurons occurred at SARs of a few W/kg. The effect was dependent on modulation but not on modulation frequency, with a threshold SAR near 0.5 W/kg. Continuous-wave radiation had no effect on the firing rate pattern at the same SAR. Mediator-induced activation of acetylcholine, dopamine, serotonin, or GABA receptors was not altered during either exposure, indicating these receptors were not responsible for the bursting effect.
Fukui Y, Hoshino K, Inouye M, Kameyama Y · 1992
Researchers exposed pregnant mice to 2.45 GHz microwave radiation for 15 or 20 minutes on day 13 of gestation. Pyknotic cell incidence in the ventricular zone was 1.83% after 15 minutes and 3.06% after 20 minutes of microwave exposure. Microwave radiation for 20 minutes produced effects comparable to immersion in 42°C hot water for 15 minutes. Brain weight was significantly lower and neuron density higher in the 20-minute exposure group compared to controls. The researchers concluded that microwave radiation at the tested dose mainly has a thermal effect.
Enin LD, Akoev GN, Potekhina IL, Oleiner VD · 1992
The study aimed to investigate the effect of extremely high-frequency electromagnetic radiation on skin sensory endings in albino rats. Researchers recorded impulse activity from solitary fibers of the tibial nerve and found that receptor units responded to mechanical stimulation of the skin. Irradiation with low-intensity millimeter-band fields at 55.61 and 73 GHz reduced receptor unit sensitivity to mechanical stimulation. Half of the receptor units stopped responding 25 minutes after irradiation, while the other half continued responding after 35 minutes but with a significantly changed response character.
Dutta SK, Das K, Ghosh B, Blackman CF · 1992
Researchers examined the impact of radiofrequency radiation exposure on acetylcholinesterase activity. Neuroblastoma cells (NG108) exposed for 30 minutes to 147-MHz radiation amplitude-modulated at 16 Hz demonstrated enhanced acetylcholinesterase activity. The authors concluded that radiofrequency radiation affects both calcium-ion release and acetylcholinesterase activity in nervous system-derived cells in culture in a common dose-dependent manner.
Maillefer RH, Quock RM · 1992
Male Swiss Webster mice were exposed to 10, 15, and 20 mW/cm2 RFR at 2450 MHz for 10 minutes at SARs of 23.7, 34.6, and 45.5 W/kg, then tested in the abdominal constriction paradigm. Confinement alone did not appreciably alter body temperature but appeared to induce stress-associated analgesia that was not blocked by naltrexone. RFR exposure raised body temperature and further increased analgesia in an SAR-dependent manner. The high SAR-induced analgesia was blocked by naltrexone, but the hyperthermia was not.
Lai H, Carino MA, Horita A, Guy AW · 1992
Researchers exposed rats to single 45-minute and repeated daily 45-minute microwave sessions at 2450 MHz, 1 mW/cm², with a whole-body SAR of 0.6 W/kg. After a single exposure, receptor concentration increased in the cerebral cortex but not in the hippocampus or cerebellum. No significant change in binding affinity of the receptors was observed in any of the brain regions studied. After repeated exposures, no significant change in receptor concentration was found in the cerebral cortex. Handling and exposure procedures did not significantly affect benzodiazepine receptors.
Lai H, Carino MA, Horita A, Guy AW, · 1992
Researchers investigated which opioid receptor subtypes mediate a microwave-induced decrease in central cholinergic activity in rats. Rats were pretreated with specific antagonists of mu, delta, and kappa opioid receptors before exposure to microwaves. All three receptor subtypes were involved in the decrease in cholinergic activity in the hippocampus.
Inaba R, Shishido K, Okada A, Moroji T. · 1992
Khramov RN, Sosunov EA, Koltun SV, Ilyasova EN, Lednev VV · 1991
Researchers studied the effects of super high frequency microwaves (34-78 GHz) on spontaneous firing rates of slowly adapting stretch-receptor neurons in crayfish. Irradiation at power densities up to 250 mW/cm2 caused a transient decrease in firing rate, and after the field was turned off the rate increased and stabilized at pre-exposure levels. Firing rates also increased when the receptor muscle was stretched and were inversely correlated with small temperature increases of about 1.5°C. The response did not depend on frequency when temperature was held constant, and no resonant peaks were found across the millimeter-wave range.
Lange DG, Sedmak J · 1991
Microwave exposure produced a dose-dependent increase in JEV-induced lethality. Hypercarbia at 5, 10, and 20% CO2 also produced a dose-dependent increase in JEV-induced lethality.
Lai H, Carino MA, Wen YF, Horita A, Guy AW · 1991
Rats were repeatedly exposed to pulsed, circularly polarized microwaves at 2,450 MHz with 2-microsecond pulses at 500 pps, a power density of 1 mW/cm², and a whole-body SAR of 0.6 W/kg. Ten 45-minute sessions increased muscarinic cholinergic receptor concentration in the hippocampus, while ten 20-minute sessions decreased concentration in the frontal cortex and hippocampus. Pretreatment with naltrexone at 1 mg/kg IP before each exposure session blocked these microwave-induced changes in cholinergic receptors.
Akyel Y, Hunt EL, Gambrill C, Vargas C Jr, · 1991
Researchers studied the behavioral effects of high-peak-power microwave pulses on Wistar rats trained to press a lever for food pellets. Each animal was exposed for 10 min to 1.25-GHz microwave radiation at 1-MW peak-power, with total doses set to 0.50, 1.5, 4.5, and 14 kJ/kg. At the highest dose, rats showed an average colonic temperature rise of 2.5 °C and failed to respond for about 13 minutes after exposure. No behavioral effects were found at the lower dose levels, and researchers concluded the effects were thermal in nature.
Ray S, Behari J · 1990
Researchers studied the effects of exposure to sublethal levels of microwaves. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves at 0.6 mW/cm2 for 3 hours daily. The exposed animals tended to eat and drink less and showed a smaller gain in body weight. Some hematological parameters and organ weights were significantly different in exposed rats. The authors proposed that a nonspecific stress response mediated through the central nervous system caused the changes.
