Adair ER, Kelleher SA, Mack GW, Morocco TS, · 1998
Thermoregulatory responses of heat production and heat loss were measured in seven adult volunteers (four women and three men, aged 21–57 years) during 45-minute dorsal exposures of the whole body to 450 MHz continuous wave RF fields. Two power densities were tested at each of three ambient temperatures (24, 28, and 31 °C), plus control conditions with no RF. No changes in metabolic heat production occurred, and deep body temperature was regulated to within 0.1 °C of the normal level through vigorous increases in sweating rate on the back and chest.
Phillips et al. · 1998
Researchers exposed Molt-4 T-lymphoblastoid cells in vitro to pulsed radiofrequency signals at cellular telephone frequencies of 813.5625 MHz (iDEN® signal) and 836.55 MHz (TDMA signal) to detect DNA damage. The alkaline comet assay was used to measure DNA single-strand breaks in exposed cell cultures compared to sham-exposed cultures. At an SAR of 24 μW g−1, exposure to the iDEN® signal for 2 h and 21 h significantly increased DNA damage, while at 2.4 μW g−1 the same signal significantly decreased DNA damage. The researchers concluded that the data indicate a need to study the effects of exposure to RF signals on direct DNA damage and on the rate at which DNA damage is repaired.
Ivaschuk OI et al. · 1997
Researchers exposed nerve growth factor-treated PC12 rat pheochromocytoma cells to a packet-modulated 836.55 MHz radiofrequency field at power densities of 0.09, 0.9, and 9 mW/cm2 for 20, 40, or 60 minutes, with an intermittent 20-minute on/off regimen. Sham-exposed cells served as controls, and c-fos and c-jun expression was measured by Northern blot analysis of total RNA. C-fos transcript levels did not change after 20 minutes at any intensity, while c-jun transcripts decreased by 38% only after 20 minutes at 9 mW/cm2.
Cain CD, Thomas DL, Adey WR · 1997
The study tested whether a TDMA-modulated RF field and the tumor promoter TPA together increase focus formation of transformed cells cocultured with parental C3H/10T1/2 murine fibroblasts. Cell cultures were exposed to an 836.55 MHz TDMA-modulated field at specific absorption rates of 0.15, 1.5, and 15 μW/g in a repeating cycle of 20 minutes on and 20 minutes off continuously for 28 days. RF exposure did not significantly alter TPA-induced focus formation at any of the tested exposure levels across multiple independent experiments.
Schilling, CJ · 1997
Donnellan M, McKenzie DR, French PW · 1997
Researchers exposed a mast cell line, RBL-2H3, to 835 MHz radiation for 20 minutes, three times per day for 7 days at a power density of 8.1 +/- 3 mW/cm2. From day 4 onward, DNA synthesis and cell replication increased, cell morphology changed, and beta-hexosaminidase release was significantly enhanced compared to unexposed cultures. No effects were seen on cytoskeletal protein synthesis or beta-actin mRNA levels. Morphological changes persisted following subculture for at least 7 days in the absence of further exposure.
Neshev NN, Kirilova EI · 1996
The authors present a theoretical model describing how pulse-modulated microwaves might influence enzyme conformational oscillations in living organisms. The model predicts that specific pulse-repetition times matching enzyme oscillation periods can produce effects at extremely low power levels. The model indicates possible environmental-health risks from long-term exposure to ambient fields from radar, navigation, and communication systems.
Maes A, Collier M, Slaets D, Verschaeve L. · 1996
Researchers exposed whole blood samples to a 954 MHz GSM base station antenna and then cultured lymphocytes with mitomycin C. They measured sister chromatid exchange frequencies in metaphase figures.
Gapeev AB, Safronova VG, Chemeris NK, Fesenko EE · 1996
Researchers compared horn, dielectric, and channel antennas for matching with biological loads. Electromagnetic radiation at 41.8-42.05 GHz inhibited luminol-dependent chemiluminescence of neutrophils activated by opsonized zymosan. No frequency dependence was found in the far field zone, but a quasi-resonance dependence appeared in the near field zone. The channel antenna provided uniform specific absorption rate distribution and wide-band matching in both near and far field zones.
Kolosova LI, Akoev GN, Avelev VD, Riabchikova OV, Babu KS · 1996
Researchers examined the effect of low-intensity millimeter wave electromagnetic radiation on regeneration of the rat sciatic nerve after transection and microsurgical reapproximation. At the twentieth postoperative day, treated animals showed a 32% increase in regeneration distance and a 26% increase in conduction velocity compared to controls.
Yoshida Y et al. · 1995
Researchers exposed pregnant rats to whole-body microwaves at 10 mW/cm2 and 2,450 MHz and measured placental blood flow and five endocrine indicators. Placental blood flow at 45-90 minutes after exposure was significantly decreased in exposed rats. Microwave exposure increased corticosterone and decreased estradiol regardless of angiotensin II pretreatment, increased progesterone and prostaglandin F2 alpha without pretreatment, and did not change prostaglandin E2. Pretreatment with angiotensin II increased placental blood flow at 15 and 30 minutes, but this effect was absent in microwave-exposed rats.
Semin IuA, Shvartsburg LK, Dubovik BV · 1995
Researchers studied the effect of weak radiofrequency radiation on DNA secondary structure stability in vitro. Exposure at 3 or 4 Hz and 0.6 mW/cm2 peak power significantly increased accumulated DNA damage, while other pulse rates or power levels eliminated the effect. DNA was incubated with glycine and formaldehyde, and damage was assessed via thermal denaturation dynamics.
Phelan AM, Neubauer CF, Timm R, Neirenberg J, Lange DG · 1994
Researchers exposed Sprague-Dawley rats to microwave radiation at 2.45 GHz and 80 mW/cm² for 30 minutes daily over four days, raising rectal temperature by 2.2°C. A separate group received radiant heat producing the same temperature rise. Microwave exposure reduced Mg(++)-ATPase activity by 48.5% and increased Na+/K(+)-ATPase activity by 170%, while radiant heat caused no significant changes in either enzyme. Microwave exposure also decreased the ratio of saturated to unsaturated fatty acids, whereas radiant heat increased it. Membrane fluidity measured by EPR differed among sham, microwave, and radiant heat groups, reflecting the fatty acid changes.
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.
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.
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.
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.
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.
Koveshnikova IV, Antipenko EN · 1991
Researchers studied whether thyroid hormones play a role in modifying the mutagenic effect of microwaves in rats. The mutagenic effect of microwaves at 2,450 or 2,750 MHz, 500 microW/cm2, for 30 days at 7 hours a day increased when rats had either low or high thyroid hormone levels. The researchers concluded that normal thyroid gland functioning appears to be an important condition for maintaining chromosome integrity under microwave exposure.
Balcer-Kubiczek EK, Harrison GH. · 1991
Researchers exposed actively growing cultures of C3H/10T1/2 cells for 24 hours to 2.45-GHz microwaves pulse-modulated at 120 Hz. The electromagnetic fields alone had no effect on cell survival or induction of neoplastic transformation. When combined with the tumor promoter TPA, the enhancement of transformation was highly significant and ranged up to a level equivalent to that produced by 1.5 Gy of X rays. The frequency of neoplastic transformation was dependent on the level of electromagnetic exposure and was additive with doses of X rays given as a cocarcinogen.
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.
D'Andrea JA, DeWitt JR, Portuguez LM, Gandhi OP. · 1988
Two experiments tested whether frequency-specific hotspot formation in the body and tail of rats would have behavioral consequences. Rats were placed in a cage where occupying one side triggered microwave exposure and occupying the other side ended it. Reduced exposure to 360-MHz and 2450-MHz microwaves at 1, 2, 6 and 10 W/kg were significantly different from 700-MHz microwaves. A second experiment found the threshold for reduced exposure to 2450-MHz microwaves fell between whole-body SARs of 2.1 and 2.8 W/kg.
