Unknown authors · 2005
Chinese researchers exposed rat brain neurons to 900 MHz microwave radiation (the same frequency used by some cell phones) at different power levels for up to 12 hours. They found that the radiation significantly reduced a key brain protein called GluR2 while increasing calcium levels inside the neurons. The effects got stronger with higher radiation doses and longer exposure times.
Lai H, Singh NP · 2004
Researchers investigated how magnetic field exposure affected brain cell DNA in rats. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hours caused a significant increase in DNA single- and double-strand breaks, and prolonging the exposure to 48 hours caused a larger increase. Acute magnetic field exposure also increased apoptosis and necrosis of brain cells in the rat.
Ilhan A et al. · 2004
Turkish researchers exposed rats to 900 MHz mobile phone radiation for one hour daily over seven days and found significant oxidative stress damage in brain tissue. The damage included increased harmful molecules and decreased protective antioxidant enzymes. However, when rats were pre-treated with Ginkgo biloba extract, this brain damage was completely prevented, suggesting that antioxidants may protect against EMF-induced cellular harm.
Unknown authors · 2004
The authors conducted an extensive literature review and propose that ELF EMF exposure increases free radical levels. They suggest EMF might induce an activated state such as phagocytosis, enhancing free radical release and leading to genotoxic events. The proposed mechanisms include direct activation of macrophages leading to phagocytosis and free radical production, and direct stimulation of free radical production by EMF-induced macrophage activation. They also propose that EMF increases the lifetime of free radicals causing persistently elevated concentrations, and that long-term exposure leads to chronically increased free radicals that inhibit melatonin effects. Taken together, these reactions could lead to higher DNA damage incidence and increased tumor risk.
Unknown authors · 2004
This 2004 research review examined how extremely low frequency (ELF) electromagnetic fields affect cells at the molecular level. The scientists proposed that EMF exposure triggers cellular activation by increasing free radical production, which could explain the wide variety of biological effects observed in EMF studies. This mechanism could potentially lead to DNA damage and increased cancer risk through chronic exposure.
Mausset-Bonnefont AL et al. · 2004
Researchers used a head-only exposure device to expose rats to 900-MHz pulsed microwaves at 6 W/kg for 15 minutes. The exposure induced a strong glial reaction in the brain, particularly in the striatum. Significant immediate effects were observed on the Kd and Bmax values of NMDA and GABA(A) receptors and on dopamine transporters, along with a decrease in NMDA receptors at the postsynaptic membrane. General locomotor behavior was not significantly altered in the short term.
Czyz J et al. · 2004
Researchers exposed wild-type and p53-deficient embryonic stem cells to GSM-217 and GSM-Talk modulated electromagnetic fields at 1.71 GHz. GSM-217 exposure significantly increased hsp70 mRNA levels in p53-deficient cells, with a transient rise in c-jun, c-myc, and p21 levels only in those cells. GSM-Talk exposure produced no gene expression changes in either cell type, and cardiac differentiation and cell cycle were unaffected by GSM-217.
Zmyslony M, Politanski P, Rajkowska E, Szymczak W, Jajte J. · 2004
Researchers tested whether 930 MHz continuous wave electromagnetic radiation affects reactive oxygen species (ROS) levels in rat lymphocytes. Acute exposure of 5 and 15 minutes did not affect ROS levels on its own. When iron ions were added to stimulate ROS production, the ROS level was significantly greater in exposed lymphocytes after both exposure durations.
Lonn S, Forssen U, Vecchia P, Ahlbom A, Feychting M. · 2004
Researchers recorded output power for all mobile phone calls managed by the GSM operator Telia Mobile during one week in four defined areas in Sweden. In the rural area, the highest power level was used about 50% of the time, while the lowest power was used only 3% of the time. In city areas, the corresponding numbers were approximately 25% and 22%. The output power distribution in all defined urban areas was similar.
Panagopoulos DJ, Karabarbounis A, Margaritis LH · 2004
The study used GSM mobile phones with a carrier frequency at 900 MHz. Insects were exposed to the near field of the mobile phone antenna for 6 minutes per day during the first 2–5 days of adult life. Modulated radiation decreased reproductive capacity by 50–60% while nonmodulated radiation decreased it by 15–20%. The authors suggested the radiation decreases the rate of cellular processes during gonad development.
Krause CM et al. · 2004
Researchers conducted a double-blind study in which subjects performed a memory task with and without exposure to a digital 902 MHz field. All eight significant EEG changes from the earlier study were not significant in this replication. The effect of EMF on incorrect answers was inconsistent, with a significant increase in errors observed in this study but not in the earlier one.
Martinez-Burdalo M, Martin A, Anguiano M, Villar R · 2004
Peak SAR1g and SAR10g trended downwards as head size decreased. The percentage of energy absorbed in the brain increased with smaller head size. SAR distributions in eyes were very similar between full-size and scaled models.
Capri M et al. · 2004
Researchers exposed human peripheral blood mononuclear cells (PBMCs) from healthy donors in vitro to a 900 MHz GSM or continuous-wave (CW) radiofrequency field for 1 hour per day for 3 days. The researchers studied mitogen-induced proliferation, cell cycle progression, spontaneous and induced apoptosis, and mitochondrial membrane potential. GSM-exposed cells showed a slight decrease in proliferation at the lowest mitogen concentration and a slight increase in cells with altered phosphatidylserine distribution, but cell cycle phases, mitochondrial membrane potential, and susceptibility to apoptosis were unaffected. When cells were exposed to the CW radiofrequency field, no significant modifications were observed for any of the endpoints studied.
Marinelli F et al. · 2004
Nylund R, Leszczynski D · 2004
Researchers exposed the human endothelial cell line EA.hy926 to mobile phone radiation and examined protein expression using two-dimensional electrophoresis. Up to 38 proteins showed statistically significant changes in expression levels after irradiation. Four proteins were identified by mass spectrometry, including two isoforms of the cytoskeletal protein vimentin.
Haarala C et al. · 2004
Researchers studied the effects of a 902 MHz mobile phone EMF on human short term memory using a double blind, multi-centre design. Sixty-four subjects in two laboratories performed an n-back task with memory loads of 0 to 3 items under both EMF and sham exposure. The EMF had no effect on reaction times or accuracy, and performance did not differ between the two laboratories.
Capri M et al. · 2004
Researchers studied whether prolonged in vitro exposure to 1800 MHz radiofrequency could affect human peripheral blood mononuclear cells from young and elderly donors by altering apoptosis, mitochondrial membrane potential, and heat shock protein 70 levels. Three GSM signal modulations (Basic, DTX, and Talk) were applied at specific absorption rates of 1.4 and 2.0 W kg−1. Endpoints were analyzed both with and without the apoptosis-inducing agent 2-deoxy-D-ribose. No significant difference was found between RF-exposed and sham-exposed cells for any endpoint. The 1800 MHz RF did not induce apoptosis on its own, did not alter apoptosis triggered by an agent, and did not change mitochondrial function or HSP 70 expression.
Unknown authors · 2004
This comprehensive Danish study followed utility workers exposed to 50 Hz power line EMF and 420,000 mobile phone users to examine cancer and disease risks. The research found no increased cancer risks from either exposure type, but identified a significant link between utility work and ALS (Lou Gehrig's disease). The findings provide important evidence about EMF safety while raising questions about specific neurological effects.
Lupke M, Rollwitz J, Simkó M. · 2004
Researchers investigated how 50 Hz extremely low frequency magnetic fields activate human cells to release reactive oxygen intermediates. They examined free radical production in human umbilical cord blood-derived monocytes and in human Mono Mac 6 cells. Exposure to 1 mT ELF-MF for 45 minutes produced a significant increase in superoxide radical anion production of up to 1.4 fold and an increase in ROS release of up to 1.2 fold in monocytes. Mono Mac 6 cells showed superoxide radical anion and ROS production of up to 1.4 and 1.5 fold, respectively, leading the researchers to suggest these cells are more sensitive to ELF-MF than monocytes.
Unknown authors · 2004
Researchers conducted a population-based case-control study in Norway to assess residential and occupational exposure to 50-Hz magnetic fields and breast cancer risk. Cases of breast cancer diagnosed from 1980 to 1996 were identified in a cohort of women living near a high-voltage power line, and each case was matched to two controls by year of birth, municipality, and cohort entry year. Residential exposure was calculated from the magnetic fields generated by the power lines before diagnosis, while occupational exposure was based on an exposure matrix. Women with residential exposure had an odds ratio of 1.58 (95% CI: 1.30, 1.92) for breast cancer, whereas the highest occupational exposure yielded an odds ratio of 1.13 (95% CI: 0.91, 1.40).
Tahvanainen K et al. · 2004
Researchers conducted a randomized, double-blind, placebo-controlled crossover trial with 32 healthy subjects exposed to 900 MHz (2 W) and 1800 MHz (1 W) cellular phone signals and sham exposure in separate sessions. Arterial blood pressure and heart rate did not change significantly during or after the 35-minute RF exposures at either frequency compared to sham exposure. Blood pressure was measured with an arm cuff and heart rate was recorded during and after each 35-minute exposure session.
Sommer AM, Streckert J, Bitz AK, Hansen VW, Lerchl A · 2004
Survival rate and lymphoma incidence did not differ between exposed and sham-exposed mice. Exposed mice gained more weight than sham-exposed mice. The data do not support the hypothesis that 900 MHz fields are a significant risk factor for lymphoma in this genetically predisposed strain.
Cobb BL, Jauchem JR, Adair ER. · 2004
Researchers exposed rats to 2450 MHz fields at 0.6 W/kg for 45 minutes daily over 10 days in circularly polarized waveguides and gave them a pre-exposure injection of a psychoactive compound or saline. Error rate analysis showed no significant effect of microwave exposure, no drug effect, and no exposure-drug interaction, while performance improved across test days indicating learning. Time to criterion showed no significant exposure effect but a significant drug effect, a significant test day effect, and a significant drug-by-test-day interaction. The authors concluded there is no evidence that microwave radiation exposure under the tested parameters caused decrements in spatial memory learning.
Unknown authors · 2004
Researchers compared two Sprague-Dawley substrains, SD1 and SD2, for magnetic field effects on cell proliferation, susceptibility to DMBA-induced mammary cancer, and tumor development in the DMBA model. The SD1 substrain was considered MF-sensitive and was compared with SD2 from the same breeder. Magnetic field exposure significantly increased mammary tumor development and growth in SD1 rats but not in SD2 rats. No enhanced cell proliferation was determined after magnetic field exposure in SD2 rats, unlike in SD1 rats. The researchers concluded that genetic background plays a pivotal role in magnetic field exposure effects.
Unknown authors · 2004
German researchers found that 50 Hz power-line magnetic fields significantly increased breast cancer development in one substrain of laboratory rats but had no effect on another genetically similar substrain. This finding helps explain why different research teams studying the same EMF exposure have reached conflicting conclusions about cancer risks.
