Lai H, Horita A, Guy AW, · 1994
After 45 minutes of exposure to pulsed 2450 MHz microwaves at 1 mW/cm², rats showed retarded learning in a radial-arm maze task, indicating a spatial working memory deficit. The memory deficit was reversed by pretreatment with the cholinergic agonist physostigmine or the opiate antagonist naltrexone, but not by the peripheral opiate antagonist naloxone methiodide. The researchers concluded that both cholinergic and endogenous opioid neurotransmitter systems in the brain are involved in the microwave-induced spatial memory deficit.
Krylova IN et al. · 1994
The study aimed to investigate the effect of ultrahigh-frequency electromagnetic radiation on learning and memory processes. Low-intensity electromagnetic field (12.6 cm, 2375 MHz, power density 1 mW/cm2) produced retrograde amnesia in the rat passive avoidance test. No effect was registered of microwave irradiation on the open field behavior and the pain sensitivity.
Dutta SK, Verma M, Blackman CF · 1994
Researchers exposed Escherichia coli cultures to electric and magnetic fields and measured the activity of enolase, an enzyme being tested clinically for detection of neoplasia. Exposure to a 147 MHz carrier wave amplitude-modulated at 16 Hz enhanced enolase activity by 62%, while modulation at 60 Hz reduced it by 28%. Exposure to 16 Hz fields alone enhanced enolase activity by 59%, while 60 Hz fields alone reduced activity by 24%. Sham exposures and continuous-wave 147 MHz radiation showed no change in enolase activity.
Dimbylow PJ, Mann SM. · 1994
Researchers built a mathematical model of the human head from MRI slices and used finite-difference time-domain (FDTD) calculations to estimate the specific energy absorption rate (SAR) at 900 MHz and 1.8 GHz. The generic transceiver was represented by a quarter-wavelength monopole on a metal box, and three placement geometries were examined: vertical in front of the eye, and vertical and horizontal at the side of the ear. For the most typical position at the side of the head, the maximum SAR averaged over 10 g of tissue was 2.1 and 3.0 W kg(-1) per W of radiated power at 900 MHz and 1.8 GHz. Placement in front of the eye gave values of 3.1 and 4.6 W kg(-1) per W averaged over 10 g of tissue at 900 MHz and 1.8 GHz.
D'Andrea JA, Thomas A, Hatcher DJ · 1994
Researchers exposed four male rhesus monkeys to high-peak-power 5.62-GHz microwave pulses while the monkeys performed an operant task for food pellet rewards. Compared to sham exposures, significant alterations of lever responding, reaction time, and earned food pellets occurred at 4 and 6 W/kg but not at 2 W/kg. There were no differences between radar pulses and SLED pulses in producing behavioral effects.
Brown DO, Lu ST, Elson EC · 1994
Researchers studied microwave evoked body movements in mice using head and neck exposure to pulsed and gated continuous wave 1.25 GHz microwaves delivered via a resonant cavity. The incidence of body movements increased proportionally with specific absorption dose when the whole-body average specific absorption rate was held constant at 7300 W/kg, reaching a plateau at 0.9 kJ/kg. For doses higher than 0.9 kJ/kg, response incidence was proportional to the specific absorption rate and reached a plateau at 900 W/kg.
Akoev IG, Mel'nikov VM, Usachev AV, Kozhokaru AF, · 1994
Researchers studied whether exposure to low-intensity radiofrequency radiation after a lethal dose of gamma-radiation could modify the resulting injury in mice. The radiofrequency exposure lasted up to 23 hours at an intensity of 5 plus or minus 1.5 microwatts per square centimeter, covering frequency ranges of 2-8, 8-18, and 19-27 GHz with a swing frequency of 12-14 Hz. A clearly pronounced modification of acute radiation injury was obtained when the radiofrequency exposure was applied immediately after the gamma-radiation.
R. Goodman et al. · 1994
The study examined how low-frequency electromagnetic fields affect levels of hsp70 transcripts in cells. In yeast cells, the SSA1 gene, which is homologous to hsp70, was found to be elevated when cells were exposed to electromagnetic fields at 0.8 to 80 μT. The researchers noted that the pattern of gene induction appeared to be related to the stress response model for heat shock.
Haider T, Knasmueller S, Kundi M, Haider M · 1994
Researchers used the Tradescantia-micronucleus bioassay to test whether short-wave electromagnetic fields used for broadcasting (10–21 MHz) may show genotoxic effects. Plant cuttings bearing young flower buds were exposed for 30 hours at various distances from broadcasting antennas, and micronucleus frequencies were compared to laboratory controls. Higher micronucleus frequencies were found at all exposure sites near the antennas where IRPA electric field strength standards were exceeded, and results at all but one site were statistically significant.
Unknown authors · 1993
Unknown authors · 1993
Researchers exposed growing Escherichia coli strain AB1157 to a 1 Hz field at 1 or 3 kV/m and found no effect on spontaneous or UV-induced mutation frequencies to rifampicin resistance. Growth in the presence of charge did not alter the UV sensitivity of strains AB1157, TK702 umuC, or TK501 umuC uvrB. Although plasmid pKM101 increased UV resistance in repair-deficient strains, pre-growth in electric fields did not further increase UV resistance, and low frequency fields did not affect mitomycin C-induced mutation frequencies.
Unknown authors · 1993
Researchers measured intracellular calcium concentration in mouse lymphocytes using a fluorescent probe during a 60-minute exposure to cyclotron resonance conditions for calcium ions. They tested resonance conditions at 16 Hz and 50 Hz with DC field amplitudes shifting the frequency up to 25 percent either side of the calculated optimum. Concanavalin A treatment increased intracellular calcium significantly, but no change was detected under any magnetic field combination tested.
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).
Unknown authors · 1993
The review discusses evidence of direct and indirect genetic toxicity effects for electric and magnetic fields at 50- and 60-Hz and miscellaneous pulsed exposures. Epidemiologic studies have reported a modestly increased risk of childhood leukemia associated with certain electric power wire configurations. Exposure conditions vary greatly among different end points measured, making comparisons and conclusions among experiments difficult. Most available evidence does not suggest that electric and/or magnetic fields cause DNA damage. Some positive findings and limitations in the studies suggest a need for additional work.
Unknown authors · 1993
Researchers examined synthesis, degradation, processing, and steady-state levels of specific RNAs in human leukemia HL-60 cells exposed to ELF fields. Overall steady-state RNA levels measured by continuous and equilibrium 3H-uridine labeling were unchanged by ELF exposure. Northern blots showed ELF did not alter steady-state levels of c-myc, beta-actin, or 45S ribosomal RNA. A nuclease protection assay found ELF increased 45S ribosomal RNA transcription by 40-50% without substantially changing c-myc or beta-actin transcription, and pulse-chase labeling showed ELF accelerated processing and degradation of the 45S transcript, reducing its half-life from 115 to 85 minutes.
Unknown authors · 1993
Researchers reviewed 55 published articles testing ELF or static electric and magnetic fields for genotoxic effects across microbial systems, plants, Drosophila, and mammalian and human cells. The preponderance of evidence indicated no clearly demonstrated genotoxic potential for either ELF or static electric or magnetic fields. However, genotoxic activity may occur under conditions producing spark discharges, electrical shocks, or corona, and two unconfirmed reports suggested co-exposure could affect the genotoxicity of chemical mutagens or ionizing radiation. The review noted gaps in test coverage for some exposure categories and suggested additional genotoxicity testing may be warranted.
Unknown authors · 1993
DMBA was given orally at 5 mg/kg on the first day and weekly thereafter up to a total dose of 20 mg per rat. Eight weeks after DMBA application, the magnetic-field-exposed rats exhibited significantly more tumors than sham-exposed animals. At the end of the three-month exposure, tumor incidence in the exposed group was 50% higher than in the sham group, a statistically significant difference. Tumor size as estimated by palpation was also significantly larger in the magnetic-field-exposed rats compared with sham-exposed rats.
Unknown authors · 1993
Unknown authors · 1993
A case-control study examined cancer incidence in children who lived within 300 meters of 220 and 400 kV power lines in Sweden from 1960 to 1985. Researchers identified 142 cancer cases, including 39 leukemia and 33 central nervous system tumor cases, and selected 558 controls from the study base. For childhood leukemia, the relative risk was 2.7 (95% CI 1.0-6.3) at 0.2 microtesla and 3.8 (95% CI 1.4-9.3) at 0.3 microtesla, with significant trends. No association was found for central nervous system tumors, lymphoma, or all childhood cancers combined.
Unknown authors · 1993
Researchers simulated cohort and case-control samples using ELF-MF exposure prevalence, childhood leukemia incidence, and confounder data from literature and existing datasets. They combined the simulated data using three methods: two-stage meta-analysis, one-stage pooling, and two-stage meta-analysis with pooling. All three methods produced estimates close to the causal estimate with no obvious overestimation or underestimation. One-stage pooling showed the widest confidence intervals but the difference was not statistically significant.
Unknown authors · 1993
Researchers simulated cohort and case-control samples using parameters from literature and existing datasets to test pooling methods for different study designs. They combined the simulated data using two-stage meta-analysis, one-stage pooling, and two-stage meta-analysis with pooling. All three methods yielded estimates close to the causal estimate with no obvious overestimation or underestimation. One-stage pooling showed the widest 95% confidence interval but the difference was not significant. The authors concluded that the performance of the three methods was not certain and further simulations are needed.
Unknown authors · 1993
Researchers observed six incident cases of testicular cancer among 340 police officers between 1979 and 1991. The observed-to-expected ratio was 6.9 with p<0.001. All six officers routinely held hand-held radar guns close to their testicles.
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.
Schwartz JL, Mealing GA · 1993
Researchers investigated the effects of AM or CW modulated 1 GHz exposure on calcium efflux and contractile force of isolated atrial muscle stripes of frog heart in vitro. Calcium efflux from electrically stimulated, 45Ca(2+)-preloaded atrial strips of the frog heart was measured from perfusate samples collected at 2-min intervals for 32 min while contractile force was simultaneously monitored. The atrial strips were exposed for 32 min to constant or amplitude-modulated 1 GHz fields at SAR ranging from 3.2 microW/kg to 1.6 W/kg with modulation at 0.5 Hz or 16 Hz. Neither unmodulated nor 0.5 Hz or 16 Hz modulated 1 GHz waves affected the movement of calcium ions or the contractile force in isolated atrial strips of the frog heart.
Rotkovska D, Bartonickova A, Kautska J · 1993
