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[Electromagnetic fields in hospitals: wireless-LAN as a risk factor?].

The actual level of exposure to non-ionizing radiation in Swiss hospitals is not well known. Therefore, the electromagnetic field of wireless LAN (WLAN) and other non-ionizing radiation sources in the publicly funded Hospital Thun (Switzerland), where WLAN supports bedside access to the computerized patient record for more than three years, has been measured. The results are compared to the international and national exposure limits for the general public. Nurse workplaces as well as patient rooms show exposure levels well below the legal (national and international) exposure limits. In the investigated patients' room the electromagnetic field of GSM and broadband cellular phone networks are dominant, whereas at the nurse workplace WLAN exposure is the most important source of exposure. The results of a questionnaire survey emphasize, that the hospital staff does not worry much about electromagnetic fields of new ICT technologies.

Attitude of Health Personnel↗

[Hygienic regulation of electromagnetic fields for the preservation of workers' health].

The article covered results of studied hygienic regulation of occupational exposure to electromagnetic fields for preservation of workers' health. Examples of examined professionals who run radar, navigation and communication means in civil airports proved adequacy of the approaches applied. The authors formulated prospective directions to further improve hygienic regulation of occupational exposure to electromagnetic fields.

Adult↗

Mechanisms of biological effects of radiofrequency electromagnetic fields: an overview.

Manmade sources of electromagnetic (EM) fields, and therefore human exposures to them, continue to increase. Public concerns stem from the effects reported in the literature, the visibility of the sources, and somewhat from confusion between EM fields and ionizing radiation. Protecting humans from the real hazards and allaying groundless fears requires a self-consistent body of scientific data concerning effects of the fields, levels of exposures which cause those effects, and which effects are deleterious (or beneficial or neutral). With that knowledge, appropriate guidelines for safety can be devised, while preserving the beneficial uses of radiofrequency radiation (RFR) energy for military or civilian purposes. The task is monumental because of the large and growing number of biological endpoints and the infinite array of RFR exposure conditions under which those endpoints might be examined. The only way to reach this goal is to understand the mechanisms by which EM fields interact with tissues. As in other fields of science, a mechanistic understanding of RFR effects will enable scientists to generalize from a selected few experiments to derive the "laws" of RFR bioeffects. This article gives an overview of present knowledge of those mechanisms and the part that the USAF School of Aerospace Medicine has played in expanding that knowledge.

Aerospace Medicine↗

Efficacy and safety of a musically modulated electromagnetic field (TAMMEF) in patients affected by knee osteoarthritis.

OBJECTIVE: Numerous studies have demonstrated the utility of extremely low frequencies (ELF) electromagnetic fields in clinical practice. Moreover, the effects of these fields seems to depend on their respective codes (frequency, intensity, waveform). In our study we want to value the effects of the TAMMEF (Therapeutic Application of a Musically Modulated Electromagnetic Field) system, which field is piloted by a musical signal. METHODS: Ninety subjects, affected by primary osteoarthritis of the knee, were enrolled in the study and randomly divided into three groups of 30 patients each: A exposed to TAMMEF, B exposed to ELF, C exposed to a simulated field. All subjects underwent a cycle of 15 daily sessions of 30 minutes each and a clinical examination upon enrolment, after 7 days of therapy, at the end of the cycle and at a follow-up 30 days later: RESULTS: All the patients of groups A and B completed the therapy without the appearance of side effects: they presented a significant improvement of the subjective pain and the functional limitation, which remained stable at the follow-up examination. In group C, there was no improvement of the pain symptoms or articular functionality. CONCLUSIONS: This study suggests that the TAMMEF system is efficacious in the control of pain symptoms and in the reduction of functional limitation in patients with knee osteoarthritis. Moreover, the effects of the TAMMEF system cover those produced by the ELF field.

Aged↗

Molecular change signal-to-noise criteria for interpreting experiments involving exposure of biological systems to weakly interacting electromagnetic fields.

We describe an approach to aiding the design and interpretation of experiments involving biological effects of weakly interacting electromagnetic fields that range from steady (dc) to microwave frequencies. We propose that if known biophysical mechanisms cannot account for an inferred, underlying molecular change signal-to-noise ratio, (S/N)gen, of a observed result, then there are two interpretation choices: (1) there is an unknown biophysical mechanism with stronger coupling between the field exposure and the ongoing biochemical process, or (2) the experiment is responding to something other than the field exposure. Our approach is based on classical detection theory, the recognition that weakly interacting fields cannot break chemical bonds, and the consequence that such fields can only alter rates of ongoing, metabolically driven biochemical reactions, and transport processes. The approach includes both fundamental chemical noise (molecular shot noise) and other sources of competing chemical change, to be compared quantitatively to the field induced change for the basic case that the field alters a single step in a biochemical network. Consistent with pharmacology and toxicology, we estimate the molecular dose (mass associated with field induced molecular change per mass tissue) resulting from illustrative low frequency field exposures for the biophysical mechanism of voltage gated channels. For perspective, we then consider electric field-mediated delivery of small molecules across human skin and into individual cells. Specifically, we consider the examples of iontophoretic and electroporative delivery of fentanyl through skin and electroporative delivery of bleomycin into individual cells. The total delivered amount corresponds to a molecular change signal and the delivery variability corresponds to generalized chemical noise. Viewed broadly, biological effects due to nonionizing fields may include animal navigation, medical applications, and environmental hazards. Understanding necessary conditions for such effects can be based on a unified approach: quantitative comparison of the estimated chemical change due to a particular electromagnetic field exposure to that due to competing influences, with both estimates based on a biophysical mechanism model within the context of a model of a biological system.

Animals↗

Electromagnetic field cancer scares.

The internal electric current or power levels that a human is likely to encounter in a typical electromagnetic field environment are calculated. At 60 Hz, a reasonable value for maximum permissible exposure is an internal current density of 1 microA cm(-2). At this frequency, a 600 V m(-1) electric field results in a current density of 0.0002 microA cm(-2), while a 200 microT magnetic field results in 0.6 microA cm(-2). This should be compared with an action potential, which is associated with a current density of 800 microA cm(-2). The ANSI/IEEE C95.1-1991 standards, whose frequency range is 3 kHz to 300 GHz, are examined. Epidemiological studies are briefly considered. The conclusion is that it is highly unlikely that there is a link between electromagnetic fields and cancer.

Animals↗

Effect of electromagnetic fields on patients undergoing massive bone graft following bone tumor resection. A double blind study.

Massive bone allograft after tumor resection has been used for over 20 years. Many factors negatively influence the healing of the junction between the allograft and the host bone, resulting in a low healing rate and lengthy time to union. This study evaluated whether pulsing electromagnetic field stimulation could be advantageously used in these patients. A double blind prospective randomized study was designed. Eighty three host graft junctions in 47 patients were considered. The overall host graft junction healing rate was the same (67%) in both control and active stimulated patients. Although not statistically significant, a positive effect of pulsing electromagnetic fields was observed for those host graft junctions with a cortico-cortical contact between allograft and host bone. When adjuvant postoperative chemotherapy was not employed, a definite effect of pulsing electromagnetic field stimulation was observed: the healing time decreased from 9.4 months in the control group to 6.7 months in the active stimulated group (p < 0.001). This effect would have been lost if chemotherapy was employed. There was also no advantage in supplement with iliac crest autografts at the host graft junction site if chemotherapy was used. Factors that significantly influenced the host graft junction healing rate were: chemotherapy; type of allograft host bone contact; quality of host graft junction; and, in intercalary allografts, use of the osteosynthesis device. No difference was observed between control and active groups for patient survival or number of local or distal tumor recurrences.

Adolescent↗

A hypothetical mathematical construct explaining the mechanism of biological amplification in an experimental model utilizing picoTesla (PT) electromagnetic fields.

We seek to answer the conundrum: What is the fundamental mechanism by which very weak, low frequency Electromagnetic fields influence biosystems? In considering the hydrophobicity of intramembranous protein (IMP) H-bonds which cross the phospholipid bilayer of plasma membranes, and the necessity for photonic recycling in cell surface interactions after dissipation of energetic states, present models lack structure and thermodynamic properties to maintain (DeltaE) sufficient energy sources necessary for amplifications by factors of 10(12). Even though one accepts that the ligand-receptor association alters the conformation of extracellular, extruding portions of IMP's at the cell surface, and that this change can be transmitted to the cytoplasm by the transmembranous helical segments by nonlinear vibrations of proteins with generation of soliton waves, one is still unable to account for repair and balanced function. Indeed, responses of critical molecules to certain magnetic field signals may include enhanced vibrational amplitudes, increased quanta of thermal energies and order inducing interactions. We may accept that microtrabecular reticulum-receptor is associated with actin filaments and ATP molecules which contribute to the activation of the cyclase enzyme system through piezoelectricity. Magnetic fields will pass through the membrane which sharply attenuates the electric field component of an EM field, due to its high impedance. Furthermore, EM oscillations are converted to mechanical vibrations; i.e., photon-phonon transduction, to induce molecular vibrations of frequencies specifically responsible for bioamplifications of weak triggers at the membrane surface, as well as GAP junctions. The hydrogen bonds of considerable importance are those in proteins (10(12)Hz) and DNA (10(11)Hz) and may be viewed as centers of EM radiation emission in the range from the mm microwaves to the far IR. However, classical electrodynamical theory does not yield a model for biomolecular resonant responses which are integrated over time and account for the connection between the phonon field and photons. Jacobson Resonance does supply an initial physical mechanism, as equivalencies in energy to that of Zeeman Resonance (i.e., zero-order magnetic resonance) and cyclotron resonance may be derived from the DeBroglie wave particle equation. For the first time, we view the introduction of Relativity Theory to biology in the expression, mc(2)=BvLq, where m is the mass of a particle in the 'box' or 'string' (molecule in a biosystem), c is the velocity of electromagnetic field in space, independent of its inertial frame of reference, B is the magnetic flux density,v is the velocity of the carrier or 'string' (a one or two dimensional 'box') in which the particle exists, L is its dimension (length) and q represents a unit charge q=1C, by defining electromotive force as energy per unit charge. Equivalencies suggest that qvBL is one of the fundamental expressions of energy of a charged wave-particle in magnetic fields, just as Zeeman and cyclotron resonance energy expressions, gbetaB and qhB/2pim, and is applicable to all charged particles (molecules in biological systems). There may exist spontaneous, independent and incessant interactions of magnetic vector B and particles in biosystems which exert Lorentz forces. Lorentz forces may be transmitted from EM field to gravitational field as a gravity wave which return to the phonon field as microgravitational fluctuations to therein produce quantum vibrational states that increase quanta of thermal energies integrated over time. This may account for the differential of 10(12) between photonic energy of ELF waves and the Boltzman energy kT. Recent data from in vivo controlled studies are included as empirical support for the various hypotheses presented.

Animals↗

[Mechanism of action of electromagnetic fields biologically adequate to man].

The paper analyzes 10-year experience in making experimental observations and clinically using electromagnetic fields (EMF) biologically adequate to man. Basic investigations of the electromechanical process that lead to the occurrence of currents in the bone tissue and blood vascular walls in their functional deformation were conducted. They showed that the piezoelectric effect is the most marked in the intact bone tissue. Experimental studies determined the amplitude and shape of impulses of currents emerging in the intact bone tissue of the extremities and in the walls of blood vessels during pulse blood filling. The bioelectric tissue metabolism changes in various human locomotor abnormalities. The lost part in the diseased area can be restored by means of external EMF. On this basis, devices for human biologically adequate electromagnetic therapy were designed. The efficiency of each session of electromagnetic therapy was evaluated from the normalization of blood circulation in the diseased area. The efficiency of this therapy in vascular disease was noted to depend on the synchronization of the generated electromagnetic pulse with the pulse wave of a patient and its phases. An experiment on 13 intact mongrel dogs was made to reveal the impact of EMF biologically adequate to man on bone marrow hemopoiesis. EMF 2 was found to have a stimulating effect on granulocytopoiesis. Platelet counts were elevated in the peripheral blood of animals. Analysing 2000 clinical cases and canine experimental findings provided evidence for the following mechanism of action of the electromagnetic fields biologically adequate to man. The fields exert a primary initial and virtually rapid action on the active areas of nerve structures and smooth muscle of blood vascular walls. They show a primary, but slower action on blood cells and on the vascular endothelial structure. There may be a secondary impact of EMF on some endocrine glands, which causes changes in the protein metabolism of a biological object and appears as stimulation of granulocytopoiesis and depot platelet release into the peripheral blood stream.

Adult↗

Effect of electromagnetic field emitted by cellular phones on fetal heart rate patterns.

The study was planned to determine the effects of electromagnetic fields produced by cellular phones on baseline fetal heart rate, acceleration and deceleration. Forty pregnant women undergoing non-stress test were admitted to the study. Non-stress test was obtained while the subjects were holding the CP on stand by mode and on dialing mode, each for 5 min. Similar recordings were taken while there were no phones around for 10 min. Electromagnetic fields produced by cellular phones do not cause any demonstrable affect in fetal heart rate, acceleration and deceleration.

Adult↗

[Effects of extremely low frequency electromagnetic fields on DNA of testicular cells and sperm chromatin structure in mice].

OBJECTIVE: To study the effects of 50 Hz electromagnetic fields (EMFs) on DNA of testicular cells and sperm chromatin structure in mice. METHODS: Mice were exposed to 50 Hz, 0.2 mT or 6.4 mT electromagnetic fields for 4 weeks. DNA strand breakage in testicular cells was detected by single-cell gel electrophoresis assay. Sperm chromatin structure was analyzed by sperm chromatin structure assay with flow cytometry. RESULTS: After 50 Hz, 0.2 mT or 6.4 mT EMFs exposure, the percentage of cells with DNA migration in total testicular cells increased from the control level of 25.64% to 37.83% and 39.38% respectively. The relative length of comet tail and the percentage of DNA in comet tail respectively increased from the control levels of 13.06% +/- 12.38% and 1.52% +/- 3.25% to 17.86% +/- 14.60% and 2.32% +/- 4.26% after 0.2 mT exposure and to 17.88% +/- 13.71% and 2.35% +/- 3.87% after 6.4 mT exposure (P < 0.05). Exposure to EMFs had not induced significant changes in S.D.alphaT and XalphaT, but COMPalphaT (cells outside the main population of alpha t), the percentage of sperms with abnormal chromatin structure, increased in the two exposed groups. CONCLUSION: 50 Hz EMFs may have the potential to induce DNA strand breakage in testicular cells and sperm chromatin condensation in mice.

Animals↗

Developmental changes in Drosophila melanogaster following exposure to alternating electromagnetic fields.

This study investigated the biological effects of alternating electromagnetic fields (EMFs) on developmental stages of Drosophila melanogaster eggs and the first, second and third instar larvae stages. D. melanogaster eggs and larval stages were exposed to a 11 mT 50 Hz field produced by a pair of Helmholtz coils. Each stage was exposed to aEMFs for 2, 4, 6 and 8 h. Features of adult flies such as head, thorax, abdomen and other morphological changes were studied and compared. The frequency of abnormal flies was calculated using statistical methods at P <.05. The results obtained from exposing larvae in different stages of development showed a significant increase in the number of abnormal adult flies, whereas no significant increase was observed in the group arising from eggs exposed to aEMFs. Also, it appeared that duration of exposure correlates with the increase in the number of abnormal flies. There was no significant difference in mortality rate and sex distribution of the abnormal flies between field exposed and the control groups.

Animals↗

[Effect of ATP and glutaminic acid on carbohydrate-energy and nitrogen metabolism in the rat brain and liver under the effect of pulsed electromagnetic field].

Oxidative phosphorylation, content of lactate, creatine phosphate, ammonia and glutamine were studied as affected by ATP and glutaminic acid in the brain and liver of rat subjected to the action of the pulsed electromagnetic field of 7 kHz frequency (72 kA/m, 15 seances). ATP (1 mg per 100 g of weight) was found to have a normalizing effect on the processes of nitrogen metabolism in the rat brain, ATP increasing the intenstiy of the oxidative phosphorylation in the tissues of intact rats, has no analogous influence on the irradiated animals. With administration of glutaminic acid (5 mg per 100 g of weight) the processes of oxidative phosphorylation and nitrogen metabolism, disturbed under the effect of the pulsed electromagnetic field are normalized.

Adenosine Triphosphate↗

Measurement of radiofrequency electromagnetic fields in and around ambulances.

Electromagnetic interference (EMI) with medical devices can threaten patient safety. More information is needed regarding circumstances in health care environments in which electromagnetic (EM) field strengths are expected to be high, such as emergency/transport. In ambulances medical devices and communications equipment must function properly in close proximity. This study characterized EM fields in and around ambulances under realistic conditions. Two types of ambulances were surveyed: the advanced life support (ALS) unit and the basic life support (BLS) unit. The surveys were conducted on-site using the ambulance mobile radio as the primary source of EM energy. Broadband field-strength measurements were collected at various locations in and around the ambulance to map interior and exterior EM field distributions. Nine ambulances were surveyed. In addition to the transmitter power and frequency, the field strengths measured were shown to be dependent upon the shielding provided by the ambulance roof and proximity of the measurement probe to the antenna. Field-strength measurements frequently exceeded the 3 V/m standard immunity level for devices set by the IEC Standard 601-1-2. The results indicate that the ambulance environment presents a considerable challenge to medical devices specifically used for emergency medical care. In order to assure their proper operation, medical devices used for transport emergency care must be able to withstand exposure to EM field strengths comparable to those reported in this study.

Ambulances↗

Effects of extremely low-frequency electromagnetic fields on three plasma membrane-associated enzymes in early chicken embryos.

Exposure to a 60 Hz, 4 uT electromagnetic field caused significant changes in levels of 5'nucleotidase (5'NT), acetylcholinesterase (AChE) and alkaline phosphatase (ALP) during early embryonic development in the chicken. Enzyme levels were significantly higher in embryos with various forms of anatomic malformations (abnormal) than in those with no visible abnormal characteristics (normal). The presence of the electromagnetic field was associated with a marked reduction in enzyme activities in abnormal embryos. Overall mean specific activities for 5'NT, AChE and ALP were 12, 57, 67 and 38, 196, 111 nmol/min/mg protein in abnormal-exposed versus abnormal-control embryos, respectively. In normal-exposed versus normal-control embryos, the values were 5, 28, 57 and 10, 29, 58, respectively.

5'-Nucleotidase↗

[Effects of exposure to extremely low frequency electromagnetic fields on reproduction of female mice and development of offsprings].

OBJECTIVE: To observe the effects of exposure to extremely low frequency electromagnetic fields (ELF EMFs) on pregnant mice and development of offsprings. METHODS: Female mice were exposed to 50 Hz, 1.2 mT electromagnetic fields during the whole pregnant period (8 h/d). The body weight of dams, delivery and development of offsprings were observed and measured. RESULTS: The increase of body weight of exposed dams (29.0%) was significantly slower than that of the control group (47.8%) during late pregnancy period (P < 0.05). The producing rate of exposed group was 60% of that of control group. Miscarriage, fetal loss and externally malformed fetus appeared in exposed group. The average number of offsprings of each exposed mouse was significantly decreased (11 +/- 1.6 vs 7 +/- 2.0, P < 0.05) and 11 for control group. Regarding the development of offspring, the body weight of prenatally exposed offsprings was increased more slowly than that of the control in the first two weeks after birth (P < 0.05). Developmental manifestations including eye opening [(252 +/- 24) h] and tooth eruption [(336 +/- 19) h] presented later in exposed offspring [(226 +/- 12), (319 +/- 15) h, respectively] (P < 0.05). CONCLUSION: Exposure to ELF EMFs during pregnancy period can cause adverse effects on pregnancy of female mice and development of offsprings.

Abnormalities, Radiation-Induced↗

[Possibility of using high-frequency electromagnetic fields for modeling local controlled hyperthermia].

The possibility to use high-frequency electromagnetic fields (13.56 MHz) as a means of controlled local heating of deep and massive tissue areas was shown in 196 experiments on tissue equivalent phantoms and 20 healthy dogs. The advantages of each type of high-frequency emitters were determined. The thermometric evaluation of heat distribution in local high-frequency heating used in complex treatment of 12 patients with sarcomas of the locomotor system confirmed the experimental results.

Animals↗

[Evaluation of the levels of radiofrequency electromagnetic fields in the territory of the city of Bari in outside and inside environments].

In this study we measured the levels of the high frequency field in the proximity of non-ionizing radiation sources (wireless transmitting stations for mobile telephones and radio and television transmitters) in nine districts of the city of Bari. The measurements were taken both inside and outside closed environments. For the indoor measurements we took into account electromagnetic field generating equipment (VDT, electric domestic appliances, mobile telephones) in working and non-working order and with the windows open and shut respectively. We carried out these measurements according to the methods laid down in the Italian regulation CEI ENV 50166-2 of May 1995, as shown in the enclosure to the Ministerial Decree of 10.9.98 n.381. The electromagnetic field levels near wireless transmitting stations for mobile telephones are certainly modest when we consider that they never exceeded the limits established by the aforesaid Ministerial Decree. On the contrary radio and television equipment creates a much greater source of exposure. The electromagnetic field levels are certainly superior to those of the wireless transmitting stations although they never exceed, except in one isolated case, the values established by the Ministerial Decree 381/98.

Cell Phone↗