Unknown authors · 1992
Researchers used a nuclear run-off assay to measure specific gene transcription in CEM-CM3 T-lymphoblastoid cells exposed to a 1 gauss, 60 Hz sinusoidal magnetic field for 15 to 120 minutes. They observed time-dependent and cell density-dependent changes in the transcription of c-fos, c-jun, c-myc, and protein kinase C beta-form. Slot-blot analysis showed that changes in transcript levels paralleled the changes in gene transcription.
Unknown authors · 1992
Researchers exposed human immune cells to 60 Hz magnetic fields at 1 gauss (similar to power line levels) for 15-120 minutes and found significant changes in gene activity. Four important genes involved in cell growth and signaling showed altered transcription patterns that varied with exposure time and cell density. This demonstrates that even brief exposure to common power line frequencies can directly affect how genes function in human cells.
Chou CK, Guy AW, Kunz LL, Johnson RB, Crowley JJ, Krupp JH · 1992
Two hundred male Sprague-Dawley rats were assigned in equal numbers to radiation-exposure and sham-exposure conditions, with exposure beginning at 8 weeks of age and continuing daily for 25 months. The experimental rats were exposed to 2,450-MHz pulsed microwaves at 800 pps with a 10-microseconds pulse width, square-wave modulated at 8-Hz. Blood samples were analyzed at regular intervals for serum chemistries, hematological values, protein electrophoretic patterns, thyroxine, and plasma corticosterone levels.
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.
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.
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.
Kues HA et al. · 1992
Researchers exposed anesthetized monkeys to pulsed 2.45 GHz microwaves after topical treatment with timolol maleate or pilocarpine. Drug pretreatment lowered the power-density threshold for corneal endothelial lesions and increased iris vascular permeability from 10 to 1 mW/cm². Effects occurred at an average SAR of 0.26 W/kg and were confirmed with specular microscopy, fluorescein angiography, and horseradish peroxidase tracer techniques.
Czerska EM, Elson EC, Davis CC, Swicord ML, Czerski P · 1992
Researchers exposed human lymphocytes in vitro for 5 days to continuous-wave (CW) or pulsed-wave (PW) 2450-MHz radiation at non-heating and heating levels, with actual average SARs ranging to 12.3 W/kg. At non-heating levels, CW exposure did not affect spontaneous lymphoblastoid transformation, but PW exposure enhanced it significantly (P less than .002). At heating levels, PW exposure enhanced transformation to a greater extent than either conventional heating or CW heating, a finding significant at the .02 level.
Phelan AM, Lange DG, Kues HA, Lutty GA · 1992
Researchers exposed B16 melanoma cells to 2.45-GHz pulsed microwaves at 10 mW/cm² for 1 hour and measured membrane ordering using electron paramagnetic resonance. The exposure shifted the cell membrane from a more fluid-like phase to a more solid, ordered state. Similar membrane ordering occurred in melanin-reconstituted liposomes, but not in amelanotic cells or liposomes without melanin. Superoxide dismutase inhibited the microwave-induced ordering, implicating oxygen radicals as a cause.
Inaba R, Shishido K, Okada A, Moroji T. · 1992
Adair ER, Adams BW, Hartman SK · 1992
Researchers exposed adult male squirrel monkeys to 450-MHz or 2,450-MHz continuous-wave fields in cool environments to study how the body responds to radio-frequency heating. During brief exposures in the cold, the reduction of metabolic heat production was directly proportional to the SAR, and 2,450-MHz energy was a more efficient stimulus than the resonant frequency. In the steady state, exposure at the resonant frequency produced a regulated increase in deep body temperature, described as not unlike that which occurs during exercise. Researchers concluded that skin temperature changes are the primary source of the neural signal for a change in physiological interaction processes during radio-frequency exposure in the cold.
Conover DL et al. · 1992
Researchers measured foot currents in workers who stood at their normal operating positions near industrial dielectric heaters generating fields at frequencies from 6.5 to 65 MHz. Nearly 27 percent of the heaters induced foot currents exceeding the proposed 200-mA ANSI C95.1 limit, and 20 percent exceeded 350 mA. Specific absorption rates in ankles were calculated from foot currents and approximated 5 W/kg at 100 mA, 29 W/kg at 250 mA, and 57 W/kg at 350 mA, with a maximum of approximately 176 W/kg at 617 mA.
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.
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.
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.
Unknown authors · 1991
Veyret B et al. · 1991
French researchers exposed mice to low-power pulsed microwaves (similar to radar frequencies) for 10 hours daily over five days to test effects on immune system function. They found that simple pulsed signals had little effect, but when the signals included additional amplitude modulation, the mice showed significant changes in antibody production - some frequencies strengthened immune responses while others weakened them.
Ciaravino V, Meltz ML, Erwin DN · 1991
Researchers exposed Chinese hamster ovary cells to adriamycin and pulsed RFR at 2,450 MHz and 33.8 W/Kg for 2 h. The maximal temperature in the tissue-culture medium was 39.7 +/- 0.2 degrees C. The experiments were controlled for chemical and RFR exposures as well as for temperature. Verified statistically, the data indicate that the RFR did not affect changes in cell progression caused by adriamycin and did not change the number of sister chromatid exchanges induced by adriamycin.
Garson OM, McRobert TL, Campbell LJ, Hocking BA, Gordon I. · 1991
Researchers studied chromosome damage in 38 radio-linemen exposed to radio-frequency radiation and 38 matched controls. They analyzed Two hundred metaphases per person, scored blind, and found the rate of aberrant cells was the same in both groups. There were no statistically significant differences in the types of chromosome aberrations.
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.
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.
Somosy Z, Thuroczy G, Kubasova T, Kovacs J, Szabo LD · 1991
Researchers exposed mouse embryo 3T3 cells to 2450 MHz continuous and 16 Hz square-modulated microwaves at absorbed energies from 0.0024 to 2.4 mW/g. Modulated waves caused more morphological changes than continuous waves at the same intensity. Cell surface negative charge decreased after modulated-wave exposure but was unchanged after continuous-wave exposure at the same dose. Modulated waves at 0.024 mW/g increased cell ruffling and caused cytoplasmic ultrastructural alterations, while continuous waves required higher doses of 0.24 and 2.4 mW/g for similar effects.
Nageswari KS et al. · 1991
Researchers exposed fourteen male Belgian white rabbits to microwave radiation at 5 mW/cm2, 2.1 GHz, three hours daily, six days a week for three months, while seven rabbits received sham exposure for the same duration. Significant suppression of T lymphocyte numbers was found in the microwave group at two months and during follow-up. Despite lower T lymphocyte counts in the blood, no significant variation was observed in tissue T lymphocyte counts, and a functional immune response test showed no impairment.
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.
Saalman E et al. · 1991
Researchers studied how 2.45 GHz microwave radiation affects the permeability of unilamellar liposomes containing a fluorescent marker. After 10 minutes of exposure, microwave-treated liposomes showed significantly greater marker release than those heated conventionally. The experiments were conducted above the lipid membrane's phase transition temperature, unlike earlier studies.
