Pakhomov AG, Dubovick BV, Degtyariov IG, Pronkevich AN · 1995
Researchers studied the combined effects of microwave radiation and drugs on an isolated frog auricle preparation. Exposure to pulse-modulated 915 MHz microwaves for up to 40 minutes had no effect on the rate or amplitude of spontaneous auricle twitches unless the absorbed power caused heating. Caffeine (1 mM) strongly increased the average heart power, and this effect was significantly augmented by about 15% under burst-type pulsed microwaves with an average SAR of 8-10 W/kg, while heating was only approximately 0.1°C.
Kakita Y et al. · 1995
Researchers studied the effect of microwave irradiation on the survival of bacteriophage PL-1 specific for Lactobacillus casei using a commercial 2,450 MHz microwave oven. Phage inactivation followed almost first-order reaction kinetics and was unaffected by continuous versus intermittent irradiation or phage concentration but was affected by suspension volume which prevented heat loss. Phage genome DNA breakage was primarily caused by heat generated by microwave irradiation, while the same temperature from external heat did not affect phage DNA.
Fesenko EE, Geletyuk VI, Kazachenko VN, Chemeris NK · 1995
Researchers observed that preliminary microwave irradiation of water solutions changes their channel-modifying activity. The irradiated solution acquires new properties important for channel activity and retains this state for at least 10-20 minutes after irradiation ends. The data suggest the field's effects on channels are mediated at least partially by changes in solution properties. Similar changes in open probability occurred when a control bath solution was replaced with a microwave-irradiated solution of the same composition (100 mmol/l KCl with Ca2+ added) after 20-30 minutes of irradiation.
Belokhvostov AS et al. · 1995
The study aimed to investigate DNA analysis of retroposon-like genetic LINE elements in blood plasma of rats exposed to radio-diapason electromagnetic waves. The elevation of LINE-elements' DNA level was revealed in blood plasma of rats exposed to electromagnetic waves. The amount of full-size 5'-containing LINE-elements copies was increased especially. The researchers supposed a connection of this effect with retrotransposon activation and genetic instability condition of organism development.
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.
Li C et al. · 1995
The study aimed to investigate biochemical indexes in white rabbit blood affected by acute high-intensity microwave. The researchers stated these changes can be used as indexes for evaluating acute high-intensity microwave exposure effects.
Geletyuk VI, Kazachenko VN, Chemeris NK, Fesenko EE · 1995
Researchers used the patch voltage-clamp method to investigate effects of millimetre microwaves at 42.25 GHz on single calcium-activated potassium channels in cultured kidney cells (Vero). Exposure to the field at non-thermal power of about 100 microW/cm2 for 20-30 min greatly modified both the Hill coefficient and an apparent affinity of the channels for Ca2+. The data suggest that the field alters both cooperativity and binding characteristics of channel activation by internal Ca2+, with effects depending on initial sensitivity of the channels to Ca2+ and the Ca2+ concentration applied.
Cao G, Liu LM, Cleary SF · 1995
Researchers exposed synchronized Chinese hamster ovary (CHO) cells to 27 MHz continuous-wave radio-frequency radiation for 2 hours at specific absorption rates of 5 or 25 W kg−1 under isothermal conditions, meaning no heating occurred. The exposure produced time- and dose-rate-dependent cell cycle alterations, with maximum responses occurring 3 days after exposure at a SAR of 25 W kg−1. Cells in G0/G1- or S-phase showed more pronounced alterations, while G2/M-phase cells showed minimal effects at either SAR.
Roy S et al. · 1995
Researchers investigated whether a low-frequency, low-intensity magnetic field could affect the oxidative burst triggered by PMA in rat peritoneal neutrophils. In the presence of the magnetic field, a 12.4% increase in the fluorescence signal was observed in PMA-stimulated neutrophils (n = 5, P < 0.02, 18 pairs of measurements). The researchers described this as what they believed to be the first experimental observation of a magnetic field influencing free radical species generated during signal transduction in living cells.
Lai H, Singh NP · 1995
Researchers measured DNA single-strand breaks in brain cells of rats acutely exposed to low-intensity 2450 MHz microwaves, using an alkaline microgel electrophoresis method. After 2 hours of exposure to pulsed microwaves, no significant effect was observed immediately after exposure, but a dose rate-dependent increase in DNA single-strand breaks was found in brain cells at 4 hours postexposure. In rats exposed for 2 hours to continuous-wave 2450 MHz microwaves at 1.2 W/kg SAR, increases in brain cell DNA single-strand breaks were observed both immediately and at 4 hours postexposure.
Unknown authors · 1994
Researchers conducted an open-field provocation in front of an ordinary TV set with two patients who regarded themselves as suffering from skin problems due to work at video display terminals. Before the provocation, skin biopsies from the anterior neck showed a high-to-very high number of somatostatin-immunoreactive dendritic cells and histamine-positive mast cells. At the end of the provocation, the number of mast cells was unchanged, but the somatostatin-positive cells had seemingly disappeared. The researchers noted that the high number of mast cells may explain the clinical symptoms of itch, pain, edema and erythema.
Unknown authors · 1994
Two pulse waveforms were tested, with rise and fall times of 85 microseconds (PMF-A) or 2.1 microseconds (PMF-B). After exposure, the eggs incubated for nine more days without fields, then embryos were examined blind. Both exposed groups had more developmental anomalies than controls, but only the PMF-B group showed a statistically significant increase (P=0.007) and a high rate of early embryonic death, while the PMF-A group's increase was not significant (P=0.173).
Philippova TM, Novoselov VI, Alekseev SI · 1994
Researchers studied the effects of continuous wave and pulse-modulated 900 MHz microwave fields on rat chemoreceptors using in vitro assays. Binding of H3-glutamic acid to hippocampal cells was unchanged after 15 minutes of continuous wave exposure at 1 W/kg, while binding of H3-dihydroalprenolol to neonatal liver-cell membranes decreased fivefold under the same conditions. The decrease was due to shedding of receptor elements into solution and correlated with oxygen concentration in the suspension.
Nelson BK et al. · 1994
Researchers exposed rats to RF radiation that maintained colonic temperature at 42.0 degrees C for 0, 10, 20, or 30 min and to 2ME at doses of 0, 75, 100, 125, or 150 mg/kg on gestation days 9 or 13. Fetuses were examined on gestation day 20 for external, skeletal, and visceral malformations. Synergistic effects were observed for some treatment combinations but not others, with highly significant effects on gestation day 13 but little effect on day 9. Statistical analyses showed no global synergistic effect but evidence of synergism at intermediate dose levels.
Libertin CR et al. · 1994
Researchers used HeLa cells with a CAT reporter driven by the HIV LTR to test the effects of various radiations. Ultraviolet light increased HIV-LTR-driven transcription. Gamma rays, limited sunlight, and electromagnetic fields did not significantly affect transcription. Microwaves did not alter expression unless heating occurred, in which case transcription was induced.
Bergqvist B et al. · 1994
Researchers studied the effect of 2.45 GHz microwave radiation on the permeability of unilamellar phosphatidylcholine liposomes. Leakage of 5(6)-carboxyfluorescein was measured using spectrofluorimetry after exposure to microwaves or thermal heating for 5-20 min intervals. The microwave exposure did not result in any non-thermal increase in permeability above that produced by thermal heating. The study refutes earlier results that reported increased liposome permeability due to microwave exposure.
Rosaspina S, Salvatorelli G, Anzanel D, Bovolenta R · 1994
Microwave exposure for 90 seconds provided effective, rapid sterilization of surgical scalpel blades contaminated with Candida albicans. Scanning electron microscopy showed that microwave irradiation induced a morphological modification of the cells. Longer exposure times caused greater alterations, with the microorganism fracturing after 9 minutes. Boiling water for the same duration killed the fungus but did not cause morphological alterations.
Lu Y, Yu J, Ren Y · 1994
Researchers measured dielectric properties of human red blood cells in suspension at 25 degrees C across 1-500 MHz using a coaxial transmission line reflection method. The study included 243 healthy persons with a hematocrit of 50%. The data revealed a statistically significant age dependence with a critical age of about 49 years, above which permittivity and conductivity decreased significantly.
Ikeda N, Hayashida O, Kameda H, Ito H, Matsuda T · 1994
Researchers investigated thermal damage to normal dog brain using 8 MHz radiofrequency interstitial hyperthermia. The heating limits were 42 degrees C for 45 min or 43 degrees C for 15 min. Breakdown of the BBB was observed at 43 degrees C for 60 min.
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.
Singh N, Rudra N, Bansal P, Mathur R, Behari J, Nayar U · 1994
Researchers exposed Twenty-three days old rats to 2.45 GHz microwaves at 1.0 mW/cm2 for sixty days and measured poly ADPR polymerase activity in various organs. The enzyme activity increased by 20% in liver and 35% in testis, while it decreased by 53% in brain diencephalon and 20% in cortex. No change was observed in spleen and kidney, and the changes were accompanied by alterations in NAD+ levels.
Salford LG, Brun A, Sturesson K, Eberhardt JL, Persson BRq · 1994
Researchers exposed male and female Fischer 344 rats to 915 MHz microwaves as continuous wave and pulse-modulated at 8, 16, 50, and 200 Hz in a transverse electromagnetic transmission line chamber. Albumin leakage occurred in 56 of 184 exposed rats versus 5 of 62 controls, and continuous wave exposure yielded 14 positive findings out of 35 that were significantly different from controls (P = 0.002). The specific energy absorption rate varied between 0.016 and 5 W/kg, and rats were exposed for 2 hours without anesthesia.
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.
Mickley GA, Cobb BL, Mason PA, Farrell S · 1994
Researchers exposed rats to various doses of microwave radiation between training and testing to study effects on working memory. Memory was assessed by measuring relative exploration time of a familiar versus a new object, with extensive re-exploration of the familiar object indicating memory loss. Rats exposed to more than 5 W/kg developed hyperthermia, and microwave-exposed rats at doses of 1, 5, 8.5, 9.3, and 10 W/kg did not show a preference for the new object, unlike normothermic controls. Microwave hyperthermia evoked prominent c-fos expression in periventricular strata, hypothalamic nuclei, amygdala, and several cortical areas.
