Thompson CJ, Anderson V, Rowley JT. · 2002
The broad objective was to assess radiofrequency exposure limits, hazard thresholds, and safety factors using probabilistic risk analysis. Analysis of SAR variables including conductivity and permittivity of grey brain matter and radiated field strengths supported the hypothesis that SAR values are lognormally distributed. The probability that SAR exceeds a threshold was derived and shown to be very low for handset SARs relative to allowable standard limits. The analysis focused on peak radiofrequency SAR values in the brain from digital mobile telephones operating at approximately 900 MHz.
Trosic I, Busljeta I, Kasuba V, Rozgaj R. · 2002
Researchers exposed adult male Wistar rats to continuous 2450 MHz radiofrequency microwave radiation for 2 hours a day, 7 days a week, for up to 30 days, at a power density of 5–10 mW/cm2. Peripheral blood smears were examined for micronuclei in polychromatic erythrocytes as an indicator of genotoxicity. Micronuclei per 1000 PCEs were significantly increased after eight irradiation treatments compared with sham-exposed controls. The researchers noted that an adaptive mechanism in both erythrocytopoiesis and genotoxicity likely appeared during the subchronic irradiation treatment.
Bartsch H et al. · 2002
Researchers tested a GSM-like RF signal on mammary tumors induced by DMBA in female Sprague-Dawley rats as a model for human breast cancer. Three experiments were carried out under strictly standardized conditions using a GSM-like signal at 900 MHz pulsed at 217 Hz. The overall results showed no statistically significant effect of RF-field exposure on tumor latency, and cumulative tumor incidence was unaffected as well. The researchers concluded that low-level RF radiation does not appear to possess carcinogenic or cancer-promoting effects on DMBA-induced mammary tumors.
Bisht KS, Moros EG, Straube WL, Baty JD, Roti Roti JL · 2002
Researchers exposed C3H 10T½ cells to 835.62 MHz FDMA or 847.74 MHz CDMA modulated radiofrequency radiation to determine whether it caused micronuclei to form. Cells were exposed at power levels of 3.2 or 4.8 W/kg for CDMA and 3.2 or 5.1 W/kg for FDMA, for durations of 3, 8, 16, or 24 hours. In three repeat experiments, no exposure condition produced a significant increase in micronuclei compared to sham-exposed cells.
Braune S, Riedel A, Schulte-Monting J, Raczek J. · 2002
The study investigated the hypothesis that exposure to EMFs can increase sympathetic vasoconstrictor activity. Forty healthy young males and females underwent a single-blind, placebo-controlled protocol on two different days with randomized EMF and placebo periods. The EMF exposure was a GSM-like signal at 900 MHz, pulsed with 217 Hz, 2 W, delivered by a mobile phone on the right side of the head. Blood pressure, heart rate, cutaneous capillary perfusion, and serum levels of norepinephrine, epinephrine, cortisol, and endothelin were measured. Systolic and diastolic blood pressure increased about 5 mmHg during the protocol, but the changes were independent of EMF exposure.
de Pomerai DI, Dawe A, DjerbibL, Allan, Brunt G, Daniells C. · 2002
Researchers investigated growth rate and maturation proportion in C. elegans exposed to prolonged microwave fields at 25°C in synchronized cultures of wild-type larvae. Microwave exposure significantly increased growth rate by 8–11% and maturation proportion by 28–40%. Mild heat treatment at 28°C decreased growth rate by 10% and almost abolished maturation proportion, showing effects opposite to microwave exposure.
McNamee JP et al. · 2002
Human blood cultures were exposed to a 1.9 GHz continuous-wave radiofrequency field for 2 hours at SARs of 0.0, 0.1, 0.26, 0.92, 2.4, and 10 W/kg while temperature was maintained at 37.0 ± 0.5°C. DNA damage was measured immediately after exposure using the alkaline comet assay with four parameters, and micronucleus formation was assessed using the cytokinesis-block micronucleus assay. No evidence of increased primary DNA damage was detected at any SAR tested. There was no significant difference in micronucleus incidence between exposed cultures and sham controls at any SAR.
McNamee JP et al. · 2002
Blood cultures from human volunteers were exposed to an acute 1.9 GHz pulse-modulated radiofrequency (RF) field for 2 h using a series of six circularly polarized, cylindrical waveguides. Mean specific absorption rates (SARs) ranged from 0 to 10 W/kg and the temperature within the cultures during the exposure was maintained at 37.0 ± 0.5°C. DNA damage was quantified in leukocytes by the alkaline comet assay and the cytokinesis-block micronucleus assay. No evidence of increased primary DNA damage was detected by the comet assay and no significant differences in micronucleus frequency were found at any SAR tested.
McNamee JP et al. · 2002
Canadian researchers exposed human white blood cells to 1.9 GHz radiofrequency radiation (similar to cell phone frequencies) for 2 hours at various power levels up to 10 W/kg. They found no DNA damage in the cells compared to unexposed controls, using two different laboratory tests to detect genetic harm. This study suggests that short-term RF exposure at these levels does not cause immediate DNA breaks in immune cells.
Unknown authors · 2002
Female Sprague Dawley rats were MF or sham exposed for 2 weeks at a flux density of 100 microTesla. Proliferation of epithelial cells in the mammary tissue and adjacent skin was examined by in vivo labeling with bromodeoxyuridine (BrdUrd) and in situ labeling of Ki-67 protein by the antibody MIB-5. MF exposure significantly enhanced BrdUrd and Ki-67 labeling in the mammary epithelium, indicating a marked increase in cell proliferation. Melatonin levels in pineal or mammary glands were not affected by MF exposure. Topical application of 12-O-tetradecanoylphorbol-13-acetate increased BrdUrd and Ki-67 labeling in skin epithelial cells, particularly hair follicles, but not in mammary tissue.
Unknown authors · 2002
German researchers exposed female rats to 50 Hz magnetic fields at 100 microTesla (similar to power lines) for two weeks and found significantly increased cell division in mammary gland tissue. The study challenges the popular "melatonin hypothesis" by showing breast tissue effects occurred without changes in melatonin levels. This provides direct evidence that magnetic field exposure can stimulate breast cell proliferation, potentially explaining increased cancer risk.
Peyman A, Rezazadeh AA, Gabriel C · 2001
Researchers measured dielectric properties of ten rat tissues at six ages from 130 MHz to 10 GHz. Results showed a general decrease in dielectric properties with age. The decrease was more apparent in brain, skull, and skin tissues than in abdominal tissues. The variation was attributed to changes in water content and organic composition.
Unknown authors · 2001
Researchers conducted a population-based case-control study across former West Germany. They measured 24-hour residential magnetic fields for 514 children with acute leukemia and 1,301 control children. Childhood leukemia and 24-hour median magnetic fields showed only a weak relationship. However, a significant association emerged for magnetic field exposure during the night.
Unknown authors · 2001
Each woman provided data over a 72-hour period in two different seasons, including bedroom magnetic field and ambient light measured every 30 seconds, personal magnetic field measured at 30-second intervals, and complete nighttime urine samples on three consecutive nights. Lower nocturnal urinary 6-sulfatoxymelatonin levels were associated with more hours of daylight, older age, higher body mass index, current alcohol consumption, and current use of beta blockers, calcium channel blockers, or psychotropics. After adjusting for these factors, higher bedroom magnetic field levels were associated with significantly lower urinary 6-sulfatoxymelatonin concentration during the same night, primarily in women using those medications and during times of year with the fewest hours of darkness.
Unknown authors · 2001
Researchers measured magnetic fields and melatonin levels in 203 women's bedrooms over 72-hour periods across different seasons. They found that higher bedroom magnetic field levels were associated with significantly lower nighttime melatonin production, particularly in women taking certain medications. This suggests that common household magnetic fields can disrupt the body's natural sleep hormone production.
Koivisto M et al. · 2001
Researchers studied the influence of pulsed radiofrequency electromagnetic fields from digital GSM mobile phones (902 MHz, 217 Hz pulse modulation) on subjective symptoms in healthy subjects using two single-blind experiments. The results did not reveal any differences between exposure and non-exposure conditions. Exposure durations were about 60 minutes in Experiment 1 and 30 minutes in Experiment 2. Subjects rated symptoms including headache, dizziness, fatigue, itching or tingling of the skin, redness on the skin, and sensations of warmth on the skin.
S. Kwee, P. Raskmark & S. Velizarov · 2001
Researchers exposed transformed human epithelial amnion (AMA) cells to a microwave field simulating the GSM signal at 960 MHz for 20 minutes. The field generated a specific absorption rate (SAR) of 2.1 mW.kg−1 in the cells, and exposures were carried out at temperatures of 35, 37, and 40 ± 0.1°C. Higher amounts of Hsp-70 were found in exposed cells at 35 and 37°C compared with sham-exposed cells, while Hsp-27 showed no significant response. The researchers considered these effects athermal because the field strength was much lower than the safety standard for absence of heat generation by microwave fields.
Tattersall JE et al. · 2001
Vijayalaxmi et al. · 2001
Researchers exposed diluted peripheral blood from four healthy volunteers to 835.62 MHz RF radiation at SARs of 4.4 or 5.0 W/kg for 24 hours. Sham-exposed and gamma-irradiated (1.50 Gy) samples served as negative and positive controls, and lymphocytes were cultured for 48 or 72 hours to assess chromosomal aberrations, micronuclei, mitotic indices, and binucleate cells. No significant differences were found between RF-exposed and sham-exposed lymphocytes for any of the measured endpoints, while gamma radiation produced significantly different responses. The authors concluded there is no evidence for induction of chromosomal aberrations and micronuclei under these exposure conditions.
Vijayalaxmi et al. · 2001
Researchers exposed peripheral blood samples from four healthy nonsmoking volunteers to 847.74 MHz CDMA radiation at SARs of 4.9 or 5.5 W/kg for 24 hours. Sham-exposed and gamma-irradiated (1.5 Gy) samples served as controls. No significant differences were found between RF-exposed and sham-exposed lymphocytes in mitotic indices, frequencies of exchange aberrations, excess fragments, binucleate cells, or micronuclei. Gamma-irradiated lymphocytes showed significantly different responses for all indices compared to both RF-exposed and sham-exposed cells. The authors concluded there was no evidence for induction of chromosome aberrations and micronuclei under these exposure conditions.
Mausset A, de Seze R, Montpeyroux F, Privat A · 2001
Researchers injected rats with gamma-vinyl-GABA to increase GABA levels and then used immunohistochemistry and image analysis to measure cerebellar GABA content. They exposed rats to 900 MHz pulsed radiofrequency at 4 W/kg SAR and continuous waves at 32 W/kg SAR. Pulsed exposure selectively reduced the stained processes area in the Purkinje cell layer, while continuous exposure decreased optical density in all three cell layers. The authors noted that it is unknown whether these effects are partly due to local tissue heating.
Maes A, Collier M, Verschaeve L · 2001
Researchers investigated cytogenetic effects of 900 MHz radiofrequency fields using chromosome aberration and sister chromatid exchange frequency methods. They studied three exposure modes (continuous, pseudo-random, dummy burst) at power outputs from 0 to 50 W. Specific absorption rates ranged from 0 to 10 W/kg. The study examined effects of radiation alone and combined with mitomycin C and X-rays. Overall, no mutagenic or co-mutagenic effect was found.
Unknown authors · 2001
Researchers independently replicated a study testing whether a 1.2 microT, 60 Hz magnetic field alters the effects of melatonin and tamoxifen on MCF-7 human breast cancer cells. In the melatonin experiment, repeated three times, melatonin reduced cell numbers by 16.7% after seven days, but this reduction disappeared when cells were exposed to the magnetic field. In the tamoxifen experiment, repeated nine times, tamoxifen reduced cell growth by 18.6% and 25% on days six and seven without the field, but only by 8.7% and 13.1% with the field. The results were consistent with the original findings of Harland and Liburdy.
Unknown authors · 2001
EPA researchers tested whether 60 Hz magnetic fields at 1.2 microT could interfere with melatonin and tamoxifen's ability to inhibit breast cancer cell growth. They found that magnetic field exposure completely blocked melatonin's cancer-fighting effects and significantly reduced tamoxifen's effectiveness. This suggests power line frequency EMF may interfere with the body's natural cancer protection mechanisms.
Lyskov E, Sandström M, Mild KH · 2001
Researchers investigated possible neurophysiological effects of an intermittent 15 sec on/off cycle, 60 Hz, 10 μT magnetic field on patients with perceived electromagnetic hypersensitivity (EHS) and control subjects during rest and a mental arithmetic task. Magnetic field exposure did not affect autonomic system or electroencephalographic variables in either group. EHS patients and controls showed significant differences in heart rate, heart rate spectrum ratio, and electrodermal activity, while EEG characteristics did not differ between groups.
