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PubMed2004

[ Effects of electromagnetic fields generated by mobile phones on the nervous system].

The authors present some data on the effects of electromagnetic fields (EMF) generated by mobile phones on the nervous system. The main attention was paid to the usefulness of some neurophysiological methods, such as electroencephalography (EEG), multimodality evoked potentials (MEP), and event related potentials (ERP) in the evaluation of the bioelectrical activity of the brain. The majority of the cited articles underline the difficulties in the evaluation of adverse effects of EMF generated by mobile phones, which can result from their nonspecific influence on biological structures.

Cell Phone↗
PubMed1994

Localizing the spatial and temporal electromagnetic fields on the axis of a lossy cylinder.

Given a specified form, both in time and space, for the electromagnetic fields on the axis of a lossy cylinder, we determine, analytically, the required azimuthally symmetric source distribution on the surface of the cylinder that generates such internal fields. We then show that this source is equivalent to an array with finite number of cylindrical slots in a metal encasing that are impulsed by specified voltages at a finite sequence of discrete times. A confirming forward calculation exhibits excellent agreement between the specified field form and that generated by the array of cylindrical slots. Potential applications are to hyperthermic cancer therapy, bioelectromagnetics and nondestructive testing.

Electromagnetic Fields↗
PubMedDate not supplied

Melatonin suppression by static and extremely low frequency electromagnetic fields: relationship to the reported increased incidence of cancer.

An increased cancer incidence has been reported in individuals living and/or working in an environment in which they are exposed to higher than normal artificial electromagnetic fields. One of the most uniform changes associated with the exposure of animals to either pulsed static geomagnetic fields or to sinusoidal extremely low frequency magnetic fields has been a reduction in high night-time levels of melatonin. Melatonin is a hormone produced especially at night in the pineal gland, a pea-sized organ near the center of the human brain. The high nocturnal production of melatonin leads to elevated blood melatonin levels at night as well. The exposure of humans or animals to light (visible electromagnetic radiation) at night rapidly depresses pineal melatonin production and blood melatonin levels. Likewise, the exposure of animals to various pulsed static and extremely low frequency magnetic fields also reduces melatonin levels. Melatonin is a potent oncostatic agent and it prevents both the initiation and promotion of cancer. Reduction of melatonin, at night, by any means, increases cells' vulnerability to alteration by carcinogenic agents. Thus, if in fact artificial electromagnetic field exposure increases the incidence of cancer in humans, a plausible mechanism could involve a reduction in melatonin which is the consequence of such exposures.

Animals↗
PubMed2004

Time-course of electromagnetic field effects on human performance and tympanic temperature.

The study aimed to investigate the time-course of electromagnetic field (EMF)-induced effects on human cognitive and behavioral performance and on tympanic temperature. Subjects were randomly assigned to two groups, exposed to a 902.40 MHz EMF before the testing session, or to the same signal during the data collecting session. Following a double-blind paradigm, subjects were tested on four performance tasks: an acoustic simple-reaction time task, a visual search task, an arithmetic descending subtraction task and an acoustic choice-reaction time task. Moreover, tympanic temperature was collected five times during each session. Results indicated an improvement of both simple- and choice-reaction times and an increase of local temperature on the exposed region under the active exposure. There was a clear time-course of the reaction time and temperature data, indicating that performance and physiological measures need a minimum of 25 min of EMF exposure to show appreciable changes.

Adult↗
PubMed1999

Diatom motility: the search for independent replication of biological effects of extremely low-frequency electromagnetic fields.

PURPOSE: To investigate the hypothesis that exposure to a certain combination of static and time-varying electromagnetic fields (EMF) results in an increase in motility of the marine diatom Amphora coffeaeformis. MATERIALS AND METHODS: Diatom motility on agar was positively correlated with calcium ion (Ca2+) concentration. In previous experiments extremely low frequency EMF (16 Hz) had the greatest effect on diatoms at suboptimal for movement Ca2+ concentrations. To ensure that the required suboptimal Ca2+ concentration and resultant cell motility were found, a number of low concentrations of Ca2+ were experimentally tested. The EMF exposure conditions were those at the calculated calcium resonances (B(V)=0 microT; B(H)=20.9 microT; B(AC)=41.8 microT peak-peak 16 Hz) previously found to cause enhanced motility. Diatom movement on agar plates under EMF and control exposures was recorded. RESULTS: There was no significant difference in cell motility between control and EMF-exposed diatoms at each Ca2+ concentration tested. CONCLUSIONS: The study indicates that low-frequency EMF set at resonance conditions did not cause an increase in motility of the diatoms.

Calcium↗
PubMed2003

Effects of chronic exposure of electromagnetic fields from mobile phones on hearing in rats.

OBJECTIVE: Little attention has been paid to the effects of electromagnetic field (EMF) of mobile phones on hearing. The aim of this study is to investigate the effects of chronic exposure to EMF emitting from mobile phones on the inner ear of adult and developing rats using distortion product otoacoustic emissions (DPOAEs). METHODS: EMF of mobile phones exposure was scheduled according to a sham-exposure controlled experimental design. Every day seven of 14 adult and four newborn rats were exposed to 1-h mobile phone EMF for 30 days, while the other seven adult rats were assigned to control group. DPOAEs were measured in both groups before and after the chronic exposure to EMF. The newborn rats were tested following similar exposure beginning on the 2nd day after birth. RESULTS: No measurable EMF associated changes in DPOAEs either in adult or developing rat inner ears were determined (P>0.05). CONCLUSION: It was concluded that chronic exposure of EMF, as long as 30 days 1 h per day, emitting from a mobile phone did not cause any hearing deterioration in adult and developing rats, at least at outer and middle ear and cochlear levels.

Animals↗
PubMed2003

Association between occupational exposure to power frequency electromagnetic fields and amyotrophic lateral sclerosis: a review.

BACKGROUND: For the past two decades, there has been concern over electromagnetic exposure and human health. While most research has focused on cancer and reproductive outcomes, there is interest in the relationship between electromagnetic fields (EMF) and neurodegenerative diseases. METHODS: We review epidemiological findings and evidence regarding the association between occupational exposure to power frequency EMFs and amyotrophic lateral sclerosis (ALS). Medline was searched for citations related to occupational hazards and ALS, literature reviews and epidemiological evaluations. RESULTS: Nine out of the ten epidemiological studies that have been conducted on the risk of ALS in relation to occupational exposure to EMF show moderate to strong relative risk estimates that supported a link between them. Although data from these studies was consistent, the causal inference to a link between EMF exposure and ALS is restricted mainly due to the lack of direct information on EMF exposure and incomplete consideration of the other potential risk factors for ALS at workplaces. For instance, electric shock, in particular, is more common in electrical occupations than in any other occupations. CONCLUSIONS: This review concludes that further studies should consider investigating the separate effect of EMF exposure and electrical shocks to make more specific interpretations. On-site measurements of EMF should be conducted to include information on EMF exposure from residences as well as workplaces to improve exposure assessment.

Amyotrophic Lateral Sclerosis↗
PubMed2006

Effect of pulsed electromagnetic fields on proteoglycan biosynthesis of articular cartilage is age dependent.

OBJECTIVE: To investigate the effects of a pulsed electromagnetic field (EMF) on articular cartilage matrix biosynthesis with regard to age and cartilage damage using a matrix depleted cartilage explant model. METHODS: Cartilage explants were obtained from metacarpophalangeal joints of calves and adult cows. After depletion of the extracellular matrix by trypsin digestion, samples were maintained in serum-free basal medium with and without the addition of interleukin 1beta (IL1beta). Half the samples were subjected to an EMF for 24 minutes daily; the other half were left untreated. Undigested and untreated explants served as negative controls. After 7 days, biosynthesis of matrix macromolecules was assessed by [35S]sulphate incorporation and values were normalised to hydroxyproline content. RESULTS: The EMF increased matrix macromolecule synthesis in undigested, untreated explants (p<0.009). In matrix depleted samples the EMF had no stimulatory effect on proteoglycan biosynthesis. IL1beta significantly decreased the de novo synthesis of matrix macromolecules (p<0.00004) in young and adult samples, but an EMF partly counteracted this inhibitory effect in cartilage samples from young, but not old animals. CONCLUSION: EMF promoted matrix macromolecule biosynthesis in intact tissue explants but had no stimulatory effect on damaged articular cartilage. The supressive effects of IL1beta were partially counteracted by EMF exposure, exclusively in cartilage derived from young animals. An EMF has age dependent chondroprotective but not structure modifying properties when cartilage integrity is compromised.

Aging↗
PubMed2000

Effect of electromagnetic field exposure on chemically induced differentiation of friend erythroleukemia cells.

Whether exposure of humans to extremely low frequency electromagnetic fields (ELF-EMF) can cause cancer is controversial and therefore needs further research. We used a Friend erythroleukemia cell line that can be chemically induced to differentiate to determine whether ELF-EMF could alter proliferation and differentiation in these cells in a manner similar to that of a chemical tumor promoter. Exposure of this cell line to 60 Hz ELF-EMF resulted in a dose dependent inhibition of differentiation, with maximal inhibition peaking at 40% and 40 mG (4 microT). ELF-EMF at 10 mG (1.0 microT) and 25 mG (2.5 microT) inhibited differentiation at 0 and 20%, respectively. ELF-EMF at 1.0 (100) and 10.0 G (1,000 microT) stimulated cell proliferation 50% above the sham-treated cells. The activity of telomerase, a marker of undifferentiated cells, decreased 100[times] when the cells were induced to differentiate under sham conditions, but when the cells were exposed to 0.5 G (50 microT) there was only a 10[times] decrease. In summary, ELF-EMF can partially block the differentiation of Friend erythroleukemia cells, and this results in a larger population of cells remaining in the undifferentiated, proliferative state, which is similar to the published results of Friend erythroleukemia cells treated with chemical-tumor promoters.

Cell Differentiation↗
PubMedDate not supplied

The effect of low force chiropractic adjustments for 4 weeks on body surface electromagnetic field.

OBJECTIVE: To study the effects of 4 weeks of low-force chiropractic adjustments on body surface electromagnetic fields (EMFs). METHOD: Thirty-five chiropractic students randomly assigned into control (17 subjects) and experimental groups (28 subjects). A triaxial fluxgate magnetometer was used for EMF detection. The subjects' body surface EMF was determined in the prone position before and after the chiropractic adjustment. A Toftness low-force chiropractic adjustment was applied to the cervical, thoracic, lumbar, and sacral areas as determined by the practitioner. Heart rate variability analysis was recorded once a week to determine autonomic nervous system activity in both the control and experimental groups. RESULTS: The EMF on the subjects' body surface decreased after chiropractic adjustment at the cervical, thoracic, lumbar, and sacral regions in all 6 visits during the 4-week treatment period. The EMF showed a downtrend over the 4-week period after the low-force adjustment. The same changes were not observed in the control group. The chiropractic adjustment group had a slight decrease in heart rate over the 4-week treatment period, and no significant change was observed in the control group. Heart rate variability analysis did not show consistent changes before and after the low-force adjustments during the treatment period. CONCLUSION: Low-force chiropractic adjustment in the cervical and thoracic areas resulted in a consistent reduction of the body surface EMF after 4 weeks of active treatment. No statistically significant differences were found in the heart rate and heart rate variability in the 4-week study.

Adult↗
PubMed1997

Testing electromagnetic fields for potential carcinogenic activity: a critical review of animal models.

In order to assess the potential of electromagnetic fields (EMF) to influence the process of carcinogenesis, it will be necessary to supplement epidemiological studies with controlled laboratory studies in animals. There are now a number of suitable assays available that focus on different histopathological forms of cancer and on different stages of carcinogenesis--induction, promotion, progression. In this review we discuss eight major systems in the context of this generalized carcinogenesis paradigm. Our aim is to bring together what is currently known about the biology of carcinogenesis in these systems in order to provide a context for evaluating EMF results as they become available. We also critically discuss EMF test results that have so far been obtained in the animal models reviewed. Most of the 19 completed studies identified were negative. However, suggestive positive results were reported in three promotion assays (in rat mammary gland, in rat liver, and in mouse skin), and in one multigeneration study in mice. Results in the rat liver assay and in the multigeneration study have only been reported in abstract form and cannot be adequately evaluated. Positive results reported in both the rat mammary gland and the mouse skin systems are of weak statistical significance and have not been independently replicated. However, it may be of interest that effects in both systems appear primarily to involve the progression stage of carcinogenesis. We suggest that more definitive conclusions as to the carcinogenic potential of EMF may require expanded test protocols that reinforce traditional carcinogenesis end points with biochemical or other parameters reflective of biological processes known to be associated with carcinogenesis in the different systems.

Animals↗
PubMed1999

Impact of extremely low frequency electromagnetic fields on CD4 expression in peripheral blood mononuclear cells.

There is increasing evidence suggesting that extremely low frequency electromagnetic fields (ELF-EMF) may influence several cell functions. Here the effects of ELF-EMF were studied on the expression of CD4+ cell surface receptors of human peripheral blood mononuclear cells (PBMC) using fluorescence-activated cell sorter (FACScan). The expression of CD4+ in ELF-EMF exposed (24, 48 and 72 h) and not exposed PBMC were not statistically significant. In addition, a flow cytometric analysis was determined by using a fluorescent labeled antibody, at 24 and 72 h incubations. The amount of bound antibody was distributed with a slight difference in the ELF-EMF-exposed PBMC compared to the not exposed cells. Moreover, DNA CD4+ expression in PBMC strongly increased in exposed cells, resting and activated with Phytohaemaglutinin (PHA). When polymerase chain reaction was performed on CD4+ mRNA of PBMC an increase of CD4+ mRNA expression was found after the resting cells were exposed to ELF-EMF at 24 h compared to not exposed cells, while at 48 and 72 h no difference was found. In the cell cycle progression analysis, the PBMC exposed to ELF-EMF presented a significant increase of percentage expression of cell cycle progression in the S phase compared to not exposed cells; while in G1 and G2 phases, there were no differences. Our results provide new evidence that ELF-EMF can affect CD4+ expression in PBMC and describe an additional biological activity for ELF-EMF affecting CD4+ transcription and translation protein and the increase of the percentage expression of the cell cycle progression of the S phase.

Blotting, Western↗
PubMed2004

High frequency electromagnetic fields (GSM signals) affect gene expression levels in tumor suppressor p53-deficient embryonic stem cells.

Effects of electromagnetic fields (EMF) simulating exposure to the Global System for Mobile Communications (GSM) signals were studied using pluripotent embryonic stem (ES) cells in vitro. Wild-type ES cells and ES cells deficient for the tumor suppressor p53 were exposed to pulse modulated EMF at 1.71 GHz, lower end of the uplink band of GSM 1800, under standardized and controlled conditions, and transcripts of regulatory genes were analyzed during in vitro differentiation. Two dominant GSM modulation schemes (GSM-217 and GSM-Talk), which generate temporal changes between GSM-Basic (active during talking phases) and GSM-DTX (active during listening phases thus simulating a typical conversation), were applied to the cells at and below the basic safety limits for local exposures as defined for the general public by the International Commission on Nonionizing Radiation Protection (ICNIRP). GSM-217 EMF induced a significant upregulation of mRNA levels of the heat shock protein, hsp70 of p53-deficient ES cells differentiating in vitro, paralleled by a low and transient increase of c-jun, c-myc, and p21 levels in p53-deficient, but not in wild-type cells. No responses were observed in either cell type after EMF exposure to GSM-Talk applied at similar slot-averaged specific absorption rates (SAR), but at lower time-averaged SAR values. Cardiac differentiation and cell cycle characteristics were not affected in embryonic stem and embryonic carcinoma cells after exposure to GSM-217 EMF signals. Our data indicate that the genetic background determines cellular responses to GSM modulated EMF. Bioelectromagnetics 25:296-307, 2004.

Animals↗
PubMed2003

Teratogenic effect of broad-band electromagnetic field on neonatal mice (Mus musculus).

Pregnant mice (Mus musculus), strain Swiss Webster, were exposed to a continuous electromagnetic field (12.8V/m) beginning in the third week of pregnancy. Histological and hematological analysis showed gender specific responses in 21 day-old mice after in-utero and post-natal continuous exposure. Automated lymphocyte percentage and total white blood cell counts were significantly elevated in exposed 21 day-old female mice compared to control mice. Lymphoma-like cells were seen in higher numbers in exposed 21 day-old male mice. Megaloblastic changes, such as hypersegmented neutrophils, were observed in exposed mice. The blood from control neonatal mice was more viscous than that of exposed mice, enough to interfere with making a blood smear. The adult female mice showed no significant differences in the above hematologic parameters between exposed and control groups. Histological study showed the following pathological changes in the adrenal cortex: degeneration/necrosis in the zona glomerulosa; hypertrophy in zona reticularis; degeneration/necrosis, intracytoplasmic inclusions and inflammation in the zona fasciculata/reticularis, more prominent in exposed female neonates; and lipidosis in the zona fasciculata. In the adrenal medulla: atrophy was more common in exposed female neonates; and intracytoplasmic inclusions and vacuolation were more common in exposed male neonates. Cystic proliferations were found in the cortical area of the thymus. In the medulla of the thymus, there was vacuolation, inflammation, or eosinophilic intracytoplasmic inclusions in exposed adults. Behavioral differences occurred in both neonates and adult females. Control neonates were able to manipulate through a maze more quickly than exposed neonates; and control adult females displayed more thorough grooming behavior than exposed mothers, and maintained more distance between the nest and dropping location than did the exposed group.

Adrenal Glands↗
PubMed2000

Prenatal exposure to 900 MHz, cell-phone electromagnetic fields had no effect on operant-behavior performances of adult rats.

To clarify potential health risks of radio-frequency electromagnetic fields (EMFs) used in cellular telephone technology to the developing brain, Wistar rats were continuously exposed during pregnancy to a low-level (0.1 mW/cm(2)) 900 MHz, 217 Hz pulse modulated EMF that approximated the highest legal exposure of normal populations to the radiation of base antennas of the GSM digital cell-phone technology. Whole body average specific absorption rate (SAR) values for the freely roaming, pregnant animals were measured in models; they ranged between 17.5 and 75 mW/kg. The offspring of exposed and of sham-exposed dams were coded and tested later as adults in a battery of ten simultaneously operated test chambers (Skinner boxes) during night time. Eight groups of ten coded animals in each group were tested for learning deficits in a sequence of nine, computer-controlled, 15 h sessions of the food-reinforced contingency Differential Reinforcement of Rate with increasing performance requirements. Two different sets of events were recorded: The food-reinforced lever-pressing activity of the animals and the inter-response intervals (IRIs) between consecutive lever presses. IRI-occurence patterns discriminated consistently between "learners" and "non-learners". Analyses of performance scores and of IRI-patterns both showed that exposure in-utero to the GSM field did not induce any measurable cognitive deficits.

Animals↗
PubMed1990

Evidence for an effect of ELF electromagnetic fields on human pineal gland function.

A study was carried out to determine possible effects of 60-Hz electromagnetic-field exposure on pineal gland function in humans. Overnight excretion of urinary 6-hydroxymelatonin sulfate (6-OHMS), a stable urinary metabolite of the pineal hormone melatonin, was used to assess pineal gland function in 42 volunteers who used standard (conventional) or modified continuous polymer wire (CPW) electric blankets for approximately 8 weeks. Volunteers using conventional electric blankets showed no variations in 6-OHMS excretion as either a group or individuals during the study period. Serving as their own controls, 7 of 28 volunteers using the CPW blankets showed statistically significant changes in their mean nighttime 6-OHMS excretion. The CPW blankets switched on and off approximately twice as often when in service and produced magnetic fields that were 50% stronger than those from the conventional electric blankets. On the basis of these findings, we hypothesize that periodic exposure to pulsed DC or extremely low frequency electric or magnetic fields of sufficient intensity and duration can affect pineal gland function in certain individuals.

Adult↗
PubMed1990

A double-blind trial of pulsed electromagnetic fields for delayed union of tibial fractures.

A total of 45 tibial shaft fractures, all conservatively treated and with union delayed for more than 16 but less than 32 weeks were entered in a double-blind multi-centre trial. The fractures were selected for their liability to delayed union by the presence of moderate or severe displacement, angulation or comminution or a compound lesion with moderate or severe injury to skin and soft tissues. Treatment was by plaster immobilisation in all, with active electromagnetic stimulation units in 20 patients and dummy control units in 25 patients for 12 weeks. Radiographs were assessed blindly and independently by a radiologist and an orthopaedic surgeon. Statistical analysis showed the treatment groups to be comparable except in their age distribution, but age was not found to affect the outcome and the effect of treatment was consistent for each age group. The radiologist's assessment of the active group showed radiological union in five fractures, progress to union in five but no progress to union in 10. In the control group there was union in one fracture and progress towards union in one but no progress in 23. Using Fisher's exact test, the results were very significantly in favour of the active group (p = 0.002). The orthopaedic surgeon's assessment showed union in nine fractures and absence of union in 11 fractures in the active group. There was union in three fractures and absence of union in 22 fractures in the control group. These results were also significantly in favour of the active group (p = 0.02). It was concluded that pulsed electromagnetic fields significantly influence healing in tibial fractures with delayed union.

Adolescent↗
PubMed2002

[A 3D FEM model for calculation of electromagnetic fields in transmagnetic stimulation].

We developed a realistic finite elements method (FEM) model of the brain for the calculation of electromagnetic fields in transcranial magnetic stimulation (TMS). A focal butterfly stimulation coil was X-rayed, parameterized, and modeled. The magnetic field components of the TMS coil were calculated and compared for validation to pointwise measurements of the magnetic fields with a Hall sensor. We found a mean deviation of 7.4% at an axial distance of 20 mm to the coil. A 3D brain model with the biological tissues of white and gray matter, bone, and cerebrospinal fluid was developed. At a current sweep of 1000 A in 120 microseconds, the maximum induced current density in gray matter was 177 mA/m2 and the strongest electric field gradient covered an area of 40 mm x 53 mm.

Brain↗