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PubMed2004

Exposure to 900 MHz electromagnetic field induces an unbalance between pro-apoptotic and pro-survival signals in T-lymphoblastoid leukemia CCRF-CEM cells.

It has been recently established that low-frequency electromagnetic field (EMFs) exposure induces biological changes and could be associated with increased incidence of cancer, while the issue remains unresolved as to whether high-frequency EMFs can have hazardous effect on health. Epidemiological studies on association between childhood cancers, particularly leukemia and brain cancer, and exposure to low- and high-frequency EMF suggested an etiological role of EMFs in inducing adverse health effects. To investigate whether exposure to high-frequency EMFs could affect in vitro cell survival, we cultured acute T-lymphoblastoid leukemia cells (CCRF-CEM) in the presence of unmodulated 900 MHz EMF, generated by a transverse electromagnetic (TEM) cell, at various exposure times. We evaluated the effects of high-frequency EMF on cell growth rate and apoptosis induction, by cell viability (MTT) test, FACS analysis and DNA ladder, and we investigated pro-apoptotic and pro-survival signaling pathways possibly involved as a function of exposure time by Western blot analysis. At short exposure times (2-12 h), unmodulated 900 MHz EMF induced DNA breaks and early activation of both p53-dependent and -independent apoptotic pathways while longer continuous exposure (24-48 h) determined silencing of pro-apoptotic signals and activation of genes involved in both intracellular (Bcl-2) and extracellular (Ras and Akt1) pro-survival signaling. Overall our results indicate that exposure to 900 MHz continuous wave, after inducing an early self-defense response triggered by DNA damage, could confer to the survivor CCRF-CEM cells a further advantage to survive and proliferate.

Apoptosis↗

PubMed2005

Histological characteristics of cutaneous and thyroid mast cell populations in male rats exposed to power-frequency electromagnetic fields.

PURPOSE: The objective of this study was to determine whether mast cells (MC) in skin and thyroid gland, cutaneous nerve fibers and eosinophils are sensitive to the influence of electromagnetic fields (EMF). MATERIALS AND METHODS: The experiment was performed on two-month-old Wistar male rats, exposed to 50 Hz EMF (100-300 microT, 54-160 V/m) for 4 h a day, seven days a week during one month. After sacrifice, samples of skin and thyroid were processed for toluidine blue staining or indirect immunohistochemistry. The M42 grid placed in the ocular of a light microscope and a special microscopic frame placed in the ocular of a fluorescence microscope were used for stereological analysis. RESULTS: The numerical and volume density of intact type A MC in the thyroid of the exposed group was significantly higher compared to the control. A number of MC and immunoreactive nerve fibers were observed in the skin and of histamine-immunoreactive MC in the thyroid of exposed animals. The differences in stereological data were not statistically significant by the Mann-Whitney test. CONCLUSIONS: The results indicate certain alterations of cutaneous and thyroid MC in rats exposed to EMF. However, the possible outcome of changes in the MC population under EMF influence on morphophysiological properties of other structures in skin and thyroid requires further investigation.

Animals↗

PubMed1983

Effect of weak, pulsing electromagnetic fields on neural regeneration in the rat.

The short- and long-term effects of pulsed electromagnetic fields (PEMFs) on the rate and quality of peripheral nerve regeneration were studied. High bilateral transections of rat sciatic nerves were surgically approximated (a 1-mm gap was left) and shielded with a Silastic sleeve. Animals were exposed to PEMFs for two to 14 weeks after operation. Three groups of 20 rats each (control rats and rats undergoing 12- and 24-hour/day PEMF exposure) were killed at two weeks. Histologically, regenerating axons had penetrated the distal stump nearly twice as far in the PEMF-exposed animals as in the control animals. Return of motor function was judged two to 14 weeks after operation by the load cell-measured, plantar-flexion force produced by neural stimulation proximal to the transection site. Motor function returned earlier in experimental rats and to significantly higher load levels than in control rats. Nerves from animals functioning 12-14 weeks after operation had less interaxonal collagen, more fiber-containing axis cylinders, and larger fiber diameters in the PEMF-exposed group than in the control rats. Histologic and functional data indicate that PEMFs improve the rate and quality of peripheral nerve regeneration in the severed rat sciatic nerve by a factor of approximately two.

Animals↗

PubMed1990

Abnormal limb regeneration in adult newts exposed to a pulsed electromagnetic field.

This investigation examined two questions: 1) whether or not forelimb regeneration results in a faithful replacement of the distal skeletal pattern and 2) what effect exposure to a pulsed electromagnetic field (PEMF), the type reported to facilitate healing of human non-united bone fractures, would have on the process of limb regeneration. Of the native forelimbs, 98% (132 out 134) had a skeletal pattern that showed little difference with the only variation being the range of carpal bones (5-8). Following a 4-5 month postamputation period, the skeletal pattern of the normal regenerates was examined. While 72% (135 out of 188) of these forelimbs resembled the native group, 28% (53 out of 188) were abnormal. These abnormalities consisted of the loss of a digit, fused carpals, and long bone defects which occurred singly or in combination with one another. Exposure to a PEMF for the first 30 days postamputation, followed by a 3-4 month postamputation period, produced in addition to the normal (60%, 144 out of 240) and abnormal forelimbs (28%, 67 out of 240), a group of forelimbs with unique gross defects (12%, 28 out of 240). These defects, occurring singly or in combination, included the loss of two or more digits with associated loss of carpals, absence of the entire hand pattern, and abnormalities associated with the radius and ulna. We can offer no explanation for these observations.

Animals↗

PubMed2006

Nuclear translocation and DNA-binding activity of NFKB (NF-kappaB) after exposure of human monocytes to pulsed ultra-wideband electromagnetic fields (1 kV/cm) fails to transactivate kappaB-dependent gene expression.

The objective of this study was to investigate whether exposure of human monocytes to a pulsed ultra-wideband electromagnetic field (EMF) of 1 kV/cm average peak power triggers a signaling pathway responsible for the transcriptional regulation of NFKB (NF-kappaB)-dependent gene expression. Human Mono Mac 6 (MM6) cells were exposed intermittently to EMF pulses for a total of 90 min. The pulse width was 0.79+/-0.01 ns and the pulse repetition rate was 250 pps. The temperature of the medium was maintained at 37 degrees C in both sham- and EMF-exposed flasks. Total NFKB DNA-binding activity was measured in the nuclear extracts by the electrophoretic mobility shift assay. Cells exposed to the EMFs and incubated for 24 h postexposure showed a 3.5+/-0.2-fold increase in the NFKB DNA-binding activity. Since activation of NFKB was observed, the possibility of kappaB-dependent gene expression in response to exposure to the EMFs was investigated using NFKB signal-specific gene arrays. The results revealed no difference in the NFKB-dependent gene expression profiles at 8 or 24 h postexposure, indicating that activated NFKB does not lead to the differential expression of kappaB-dependent target genes. To determine whether the absence of the kappaB-dependent gene expression was due to compromised transcriptional regulation of NFKB, the functional activity of NFKB was examined in cells transiently transfected with Mercury Pathway constructs containing 4x NFKB binding sites associated either with the luciferase reporter system or a control vector. Pulsed EMF exposure did not induce NFKB-driven luciferase activity in these cells, indicating that the activation of NFKB at 24 h after the 1 kV/cm EMF exposure is functionally inactive. From these results, it is clear that the EMF-induced NFKB activation is only a transient response, with minimal or no downstream effect.

Active Transport, Cell Nucleus↗

PubMed2001

Effects of low frequency electromagnetic fields on expression of lymphocyte subsets and production of cytokines of men and women employed in a museum.

The objective of this study was to analyse the immune response to electromagnetic fields (ELMFs) in seven men and eight women employed in a museum. The workers were exposed in a room to an ELMFs (range 0.2-3.6 microT and 40-120 V/m) induced by 50 Hz electricity for 20 h a week. Control groups consisted of 47 women and 39 men with a similar percentage of atopic subjects, age (range 30-51 years) and smoking habits of the workers included in the study. Levels of blood lead (Pb) and urinary trans-trans muconic acid, a metabolite of benzene (markers of exposure to traffic and smoking) of the control and exposed groups were similar. Lymphocyte subsets were determined in men and women using conjugated antibodies. Serum interleukin (IL) 4 and interferon gamma and their 'in vitro' production by peripheral mononuclear blood cells (PMBCs) stimulated by phytohemoglutinin (PHA), as well as blastogenesis of PMBCs induced by PHA, were determined in women only. ELMF-exposed women showed a significant reduction in the percentage of B and NK CD3(-)-CD25+ lymphocytes and a slight reduction of CD16(+)-56+ NK lymphocytes. They also showed significantly lower levels of interferon gamma in serum, or produced in the supernatants by PMBCs both spontaneously and stimulated by PHA, while they did not show significant changes in serum and 'in vitro' produced IL-4, or in blastogenesis of PMBCs. Men working in the museum showed, in relation to the controls, a statistically significant reduction in both number and percentage of CD16(+)- CD56+ and CD3(-)-CD25+ lymphocyte subsets. On the whole, this investigation demonstrates a reduction of blood NK lymphocytes and of the production of interferon gamma in workers exposed to low frequency ELMFs. Recent studies have shown that stress and poor lifestyle induce the reduction of blood cytotoxic activities possibly acting on nervous functions. This may suggest that ELMFs reduces blood NK lymphocytes by combined effects on the immune and nervous systems.

Adult↗

PubMed2006

Studies on antioxidant enzymes in mice exposed to pulsed electromagnetic fields.

In this study, 56 female albino mice weighing 30-35 g were used. The animals were divided into a control and an experimental group. The animals in the experimental group were subjected to a pulsed electromagnetic field (PEMF) with a field magnitude of 50 Hz and 2 mT for 8h each day between 0900 and 1700 for 90 days. In both control and experimental groups, blood was sampled at 45, 60, and 90 days in heparinized tubes and erythrocyte malondialdehyde levels, and superoxide dismutase, glutathione peroxidase, catalase, and glucose-6-phosphate dehydrogenase activities were determined. The results revealed that the PEMF applied chronically within the given period and field magnitude does not cause oxidative damage.

Animals↗

PubMed1995

Exposure to electromagnetic fields during pregnancy with emphasis on electrically heated beds: association with birthweight and intrauterine growth retardation.

Several animal and human studies indicate that fetal growth may be retarded following exposure to electromagnetic fields (EMF). We conducted a prospective study (N = 2,967) to evaluate the relation of birthweight and fetal growth retardation with use of electrically heated beds (electric blankets and heated water beds) during pregnancy. A "nested" study design allowed monitoring of exposure at different stages of pregnancy using both direct and indirect methods. We assessed EMF exposure using personal monitors, home measurement, video display terminal use, and wire code. Exposure to EMF during pregnancy, either at conception, at < or = 16 weeks, or in the third trimester, showed no important relation to risk of low birth-weight or fetal growth retardation. This result was the same whether we used subjective measures of exposure or direct measurement. Use of video display terminals at home or work, exposure to > or = 2.0-milligauss fields as measured by home or personal monitors, and home wire code were unrelated to the reproductive outcomes studied. A time-weighted analysis of electric bed use, which accounted for strength of EMF exposure and hours of use, also showed evidence of no meaningful increase in risk. None of the exposure measures showed a dose response relation to risk. We conclude that risk of low birth-weight and intrauterine growth retardation is not increased after electrically heated bed use during pregnancy.

Adult↗

PubMed2003

[Protection against electromagnetic fields 0-300 GHz in Poland. New regulations and perspectives if their harmonization wit the European Union requirements].

A critical review of protection regulations (or their proposals) on work safety regarding electromagnetic fields as well as the general public protection against unwanted exposure to the fields are presented in this paper. The standards of the Western World are illogical in both aspects, biomedical knowledge and technical. The results (permissible exposures) are defined more precisely than the input data. In Poland, two independent acts are in force: one on occupational exposures and the other on non-occupational exposures. The former is "a world-better", but requires to be immediately changed to a standard that is applicable and friendly to its users. The latter can be accepted after introducing several amendments. The enlargement of the environmental standard to include occupational issues may create a good Polish proposal also useful at the international level.

Dose-Response Relationship, Radiation↗

PubMed2001

Assessment of the temporal trend of the exposure of people to electromagnetic fields produced by base stations for mobile telephones.

Monitoring of electric field levels produced by base stations (BSs) for mobile telephones of different typologies (TACS. GSM, DCS) has been carried out. Results show that BSs can be classified as 'business' or 'residential'. The mean value of six minutes averaged E-field value measured between 10 a.m. and 1 p.m. corresponds to the 84% of the maximum daily six minutes averaged value. Comparison between electromagnetic field levels produced by BSs and their phone traffic data, supplied by companies, is shown. Finally, on an hourly average basis, a daily curve has been constructed of the exposure trend produced by such installations.

Electromagnetic Fields↗

PubMed2006

[Regulation requirements for new investments to protect the environment against electromagnetic fields].

The date of 28 July 2005, when the amendments to the Environmental Protection Act and related acts entered into force, is crucial for the future installations of the majority of electromagnetic fields emitters. Since the amendments let the environmental protection assessment procedures be more "independent", set the decision on environmental conditions for development consent and transposed the rules of managing and protection of Natura 2000 sites, they are considered as a revolution in the environmental impact assessment system. According to new rules, the decision on environmental conditions for development consent is granted for the project that may have a significant impact on the environment listed in the regulation issued by the Council of Ministers on 9 November 2004 on the types of projects that may have significant impact on the environment and detailed criteria for screening of the projects for which the environmental impact report may be required or for other projects that may have significant impact on Natura 2000 sites.

Electromagnetic Fields↗

PubMed2001

[Immunotropic effects of electromagnetic fields in the range of radio- and microwave frequencies].

On the grounds of reviewed literature and the results of own experiments, the authors present current views on the possible immunotropic influence of low energy electromagnetic fields, in the range of radio- and microwave frequencies. They conclude, that a more systematic and multidisciplinary investigations should be undertaken, comprising the wide spectrum of immune homeostatic tasks, including defensive, immunoregulatory and pro-regenerative capabilities of immune system exposed to rapid environmental spread of different electromagnetic emitters.

Animals↗

PubMed1982

Congenital pseudoarthrosis of the tibia: treatment with pulsing electromagnetic fields.

Ninety-two patients with congenital pseudoarthrosis (infantile nonunion) were treated with pulsing electromagnetic fields (PEMF) in the United States and Europe in the past eight years. This represents the largest group of patients with infantile nonunions in which a common treatment modality has been used. Excluding the ten lesions (11%) which healed with refracture 48 lesions (59%) healed whereas 34 (41%) failed to heal. The success rate in 23 type I and 34 Type II lesions was 77% and 76%, respectively. Surgery in association with PEMF treatment did not improve the results of treatment. The most important variable was the radiographic morphology of the nonunion gap. Patients with spindled bone ends, a large gap and a grossly mobile lesion had a very poor prognosis relative to patients with a cystic or sclerotic transverse fracture line with a gap of less than 5 mm. The key to success in the treatment of infantile nonunions has been the combination of PEMF treatment with good orthopedic management, consisting of rigid immobilization, a nonweight-bearing status and rehabilitation with impact loading exercise. Infantile nonunion remains a major challenge to the orthopedic surgeon, but PEMFs appear to offer some important advantages for overcoming this pernicious condition. Dr. Harold Boyd's discussion of this paper follows. It was his final address to the AAOS.

Amputation, Surgical↗

PubMed2002

Simulation of electromagnetic fields in the human body using Finite Integration Technique (FIT).

In the last years, worldwide scientific communities working in the area of computational biology and medicine have shown an increasing interest to the problem of computation of electromagnetic fields in the human body and safety aspects of human exposure to RF radiation. In this paper we investigate the influence of the frequency of mobile phones upon the electromagnetic energy absorption in tissues and express it as specific absorption rate (SAR) calculated with an algorithm based on Finite Integration Technique for a mobile phone excited with two different frequencies: 900 MHz and 1800 MHz. A three-dimensional human model based on anatomical data, which describes the conductivity distribution in the human body, is used in these simulations.

Body Surface Area↗

PubMed2001

25 Hz electromagnetic field exposure has no effect on cell cycle distribution and apoptosis in U-937 and HCA-2/1cch cells.

It is reported that exposure to 50 Hz extremely low-frequency electromagnetic field (ELF-EMF) can produce apoptosis and small variations in cell cycle distribution on different cell lines. In order to study the effect of ELF-EMF on tumoral cells in vitro, two cell lines (U-937, from a histiocytic lymphoma, and HCA-2/1cch, from a human colon adenocarcinoma) were exposed to 25 Hz, 1.5 mT, for 2 h and 45 min. Cell cycle distribution, apoptosis (spontaneous and dexamethasone-induced) and cell growth were evaluated. Neither significant alteration in cell cycle phases nor induction of apoptosis was observed. Nevertheless, the relative cell number was found to decrease to 55.84+/-7.35% (p <0.05, Student's t-test) for HCA-2/1cch cells after exposure to EMF in the presence of dexamethasone. The presence of dexamethasone during the EMF exposure could probably produce a decrease in the cell growth of this cell line.

Apoptosis↗

PubMed1985

Pulsed electromagnetic fields promote collagen production in bone marrow fibroblasts via athermal mechanisms.

Primary and passaged cultures of fibroblasts (RBMFs) raised from the bone marrow stroma of young rabbits were treated with pulsed electromagnetic fields (PEMFs) from the start of each culture until 1 week after they became confluent. the PEMF treatment had no effect on cell proliferation, estimated by phase contrast microscopy, by 3H-thymidine incorporation into DNA, or by total DNA assay. Collagen production, estimated by conversion of 3H-proline to 3H-hydroxyproline in nondialyzable material was markedly elevated in postconfluent cultures, but not in cultures that had only just reached confluence. About 65 of 3H-hydroxyproline was in low molecular weight form, and a correlation between collagen breakdown and cyclic AMP (cAMP) levels in RBMFs was demonstrated by adding dibutyryl cAMP or prostaglandin E3 (PGE2) to the culture medium concurrently with 3H-proline. The PEMF apparatus caused an insufficient temperature rise (less than 0.1 degree C) to account for these results. We propose that the rise in collagen production is consistent with the hypothesis that PEMFs act by reducing cAMP levels in RBMFs, and that thermal effects are insignificant.

Animals↗

PubMed2005

Effect of high-frequency electromagnetic fields with a wide range of SARs on chromosomal aberrations in murine m5S cells.

To investigate the induction of chromosomal aberrations in mouse m5S cells after exposure to high-frequency electromagnetic fields (HFEMFs) at 2.45 GHz, cells were exposed for 2 h at average specific absorption rates (SARs) of 5, 10, 20, 50 and 100 W/kg with continuous wave-form (CW), or at a mean SAR of 100 W/kg (with a maximum of 900 W/kg) with pulse wave-form (PW). The effects of HFEMF exposure were compared with those in sham-exposed controls and with mitomycin C (MMC) or X-ray treatment as positive controls. We examined all structural, chromatid-type and chromosome-type changes after HFEMF exposures and treatments with MMC and X-rays. No significant differences were observed following exposure to HFEMFs at SARs from 5 to 100 W/kg CW and at a mean SAR of 100 W/kg PW (a maximum SAR of 900 W/kg) compared with sham-exposed controls, whereas treatments with MMC and X-rays increased the frequency of chromatid-type and chromosome-type aberrations. In summary, HFEMF exposures at 2.45 GHz for 2 h with up to 100 W/kg SAR CW and an average 100 W/kg PW (a maximum SAR of 900 W/kg) do not induce chromosomal aberrations in m5S cells. Furthermore, there was no difference between exposures to CW and PW HFEMFs.

Adsorption↗

PubMedDate not supplied

Healing of chronic arterial and venous leg ulcers through systemic effects of electromagnetic fields [corrected].

BACKGROUND: Mitogen-activated autologous peripheral blood mononuclear cells applied locally on the ulcer surface promote healing of chronic arterial and venous leg ulcers. In vitro, extremely low frequency electromagnetic fields (ELF) interact with peripheral blood mononuclear cells (PBMC) via Ca++ channels, activating signal transduction cascades, promoting cytokine synthesis, and changing cell proliferation patterns. METHODS: ELF frequencies were configured to interact in vitro with the proliferation patterns of PBMC obtained from normal human volunteers. These ELF were then applied peripherally as the sole treatment to 26 patients with 42 chronic leg ulcers of predominantly arterial or venous etiology unresponsive to previous medical and/or surgical treatments in a phase I before-after design. RESULTS: At admission, age of ulcers had a skewed distribution with a median of 639 days. Wound healing or deleterious effects began in all patients during the first 2 weeks after ELF exposure, permitting their previously unresponsive ulcers to function as internal controls. After ELF exposure, 69% of all lesions were cured or healed >50% in a period <4 months. Defective wound healing was observed in lesions associated with important arterial occlusion, uncontrolled arterial hypertension, severe lipodermatosclerosis, non-pitting edema, and obesity (body mass index >30). Lesions worsened in patients with autoimmune diseases. CONCLUSIONS: Systemic effects are hypothetically explained by ELF activation of PBMC and their subsequent transportation to the ulcer site via humoral route. This therapy is effective in selected patients with chronic arterial and venous leg ulcers.

Arteries↗