Yee KC, Chou CK, Guy AW · 1994
Researchers investigated the effect of microwave exposure on conduction velocity of frog ventricular muscle. Thirty-two frog hearts were divided into four groups and placed in temperature-controlled waveguides with Ringer's solution. One group served as control while three groups were exposed for 2 hours to pulsed 2,450 MHz microwave fields at SARs of 0.003, 2, and 6 W/kg. No significant difference in conduction velocity was found between control and exposed groups.
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.
Zhao Z, Zhang S, Wang S, Yao Z, Zho H, Tao S, Tao L · 1994
The study aimed to investigate exposure limits for ultra-short wave radiation in work environments. Eighteen male rabbits were divided into four groups; three groups were irradiated with ultra-short waves at 100 MHz at power densities of 35, 1.5-3.5, and 0.07 mW/cm2 for 3 hours per day, 5 days per week for 24 weeks. Thermal effects occurred at 35 mW/cm2 and the thermal threshold limit value was set at 1.5 mW/cm2. An epidemiological survey of 136 factory workers and TV operators exposed to 0.2 mW/cm2 for over one year was compared with 108 controls. The exposure limit value for short wave radiation was set at 0.2 mW/cm2 using 15- and 20-fold safety factors.
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.
Quock RM, Klauenberg BJ, Hurt WD, Merritt JH · 1994
Researchers tested male mice in the staircase test after pretreatment with chlordiazepoxide at 8, 16, and 32 mg/kg and a 5-min exposure to microwave radiation at 4, 12, and 36 W/kg (1.8 or 4.7 GHz). In sham-irradiated mice, increasing CDP doses first increased steps ascended without affecting rears, then increased steps ascended and decreased rears, and finally decreased both measures. Microwave exposure did not alter steps ascended or rears at lower CDP doses, but at 32 mg/kg CDP, 36 W/kg microwave at 4.7 GHz significantly reversed the reductions in both measures.
Somosy Z, Thuroczy G, Koteles GJ, Kovacs J · 1994
Researchers investigated the distribution and activity of Ca(2+)-ATPase in small intestine epithelial cells of mice after total body exposure to 2450 MHz microwave irradiation modulated at 16 Hz and X-ray irradiation. In control animals, enzyme activity was present in the brush border and lateral membranes, and lateral membrane activity was inhibited by quercetin. Microwave irradiation immediately decreased Ca(2+)-ATPase activity on lateral membranes, 1 Gy X-ray caused a similar reversible decrease within 24 hours, and 5 Gy X-ray reduced activity on both apical and lateral membranes persisting up to 24 hours.
Unknown authors · 1993
Unknown authors · 1993
Maes A, Verschaeve L, Arroyo A, De Wagter C, Vercruyssen L · 1993
Researchers exposed human peripheral blood lymphocytes to 2450 MHz microwaves for 30 and 120 minutes at constant body temperature. Exposure caused a marked increase in chromosome aberrations, including dicentric chromosomes and acentric fragments, and micronuclei. Microwave exposure did not influence cell kinetics or sister chromatid exchange frequency.
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.
Litovitz TA, Krause D, Penafiel M, Elson EC, Mullins JM, · 1993
The study investigated the role of coherence time in the effect of microwaves on ornithine decarboxylase activity. Amplitude-modulated 915 MHz microwaves at SAR 2.5 W/kg modulated at 55, 60, or 65 Hz approximately doubled ornithine decarboxylase activity after 8 h, and switching modulation frequencies at coherence times of 1.0 s or less abolished the enhancement while times of 10 s or longer provided full enhancement.
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).
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.
Ellingsrud S, Johnsson A · 1993
Researchers studied the up-and-down rhythmic movements of the lateral leaflets of Desmodium gyrans when exposed to electromagnetic radiation in the radio-frequency range. The RF radiation was applied as homogeneous 27.12 MHz fields in specially-designed exposure cells, and in some cases as non-homogeneous radiation of 27 MHz amplitude modulated by 50 Hz in front of commercial diathermy equipment. The radiation caused temporary changes in amplitude, period, and phase, and could also cause temporary or complete cessations of the rhythms.
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.
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.
Seaman RL, DeHaan RL · 1993
Researchers studied inter-beat intervals of aggregated cardiac cells from chicken embryos during 190-second exposures to 2.45 GHz microwaves. The inter-beat interval decreased during exposures at 42.0 W/kg and higher with continuous-wave or square-wave modulation, consistent with thermal effects. Increases occurred during continuous-wave exposures at 1.2-12.2 W/kg and decreases after pulse-modulated exposures at 8.4-12.2 W/kg, which were not consistent with simple thermal effects.
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.
Somosy Z, Thuroczy G, Kovacs J · 1993
Researchers investigated pyroantimonate-precipitable calcium in mouse intestinal epithelial cells after whole-body exposure to 2450 MHz continuous and 16 Hz square-modulated microwaves. Immediately after modulated irradiation at 0.5 and 1 mW/cm², calcium deposits rapidly appeared on the cytoplasmic side of lateral membranes and in the junctional complex including tight junctions. These changes were reversible, with calcium distribution returning to control-like patterns after 24 hours. Continuous-wave exposure at the same energy did not alter calcium distribution.
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.
Rotkovska D, Bartonickova A, Kautska J · 1993
Lange DG, D'Antuono ME, Timm RR, Ishii TK, Fujimoto JM. · 1993
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.
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
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.
