bluuebunny/crossref_metadata_2025 huggingface dataset:
Magnetic‐field flux density and spectral characteristics of motor‐driven personal appliances
Authors: Wilson Bary W. , Hansen Norman H. , Davis Karl C.
Published: February 2006

Flux density and spectral measurements were carried out on magnetic fields generated by several types of motor‐driven personal appliances used near the body. Among the units tested were several for which the average flux densities, as determined at the surfaces of the appliance, exceeded 0.4 mT. Time‐rates‐of‐change (dB/dt) for several units exceeded 1000 T/s, and several units exhibited high‐frequency components in the low‐MHz range. Use of such appliances, although normally of short duration, can represent exposure to magnetic fields of relatively high flux density, which may also have high‐frequency components. Compared to other household and commercial sources of magnetic fields, those generated by certain motor‐driven personal appliances may represent a significant contribution to time‐weighted average exposure and may represent an important source of local induced currents in the body. Furthermore, high‐frequency transients that represent only a minor contribution to time‐weighted average exposure may generate significant instantaneous induced currents. © 1994 Wiley‐Liss, Inc.

This article is a US Government work and, as such, is in the public domain in the United States of America.
Dose response study of human exposure to 60 Hz electric and magnetic fields
Authors: Graham Charles , Cook Mary R. , Cohen Harvey D. , Gerkovich Mary M.
Published: February 2006

This human exposure study examined the relationship between field strength and biological response and tested whether the exposure levels at which the greatest effects occur differ for different endpoints. Three matched groups of 18 men each participated in two 6 h exposure test sessions. All subjects were sham exposed in one session. In the other session, each group of subjects was exposed at a different level of combined electric and magnetic field strength (low group: 6 kV/m, 10 μT; medium group: 9 kV/m, 20 μT; and high group: 12 kV/m, 30 μT). The study was performed double blind, with exposure order counterbalanced. Significant slowing of heart rate, as well as alterations in the latency and amplitude of event‐related brain potential measures derived from the electro encephalogram (EEG), occurred in the group exposed to the 9 kV/m, 20 μT combined field (medium group). Exposure at the other field strength levels had no influence on cardiac measures and differential effects on EEG activity. Significant decrements in reaction time and in performance accuracy on a time estimation task were observed only in the low group. These results provide support for the hypothesis that humans may be more responsive to some combinations or levels of field strength than to others and that such differences in responsivity may depend, in part, on the endpoint of interest. © 1994 Wiley‐Liss, Inc.
Recovery of nocturnal melatonin concentration takes place within one week following cessation of 50 Hz circularly polarized magnetic field exposure for six weeks
Authors: Kato Masamichi , Honma Ken‐Ichi , Shigemitsu Tsukasa , Shiga Yoichi
Published: February 2006

In our earlier paper [Kato et al. (1993): Bioelectromagnetics 14:97–106], melatonin concentration in pineal gland and blood was reported to be suppressed after exposure to a circularly polarized 50 Hz magnetic field for 6 weeks. In the present series of experiments, we investigated the time course of recovery after cessation of the exposure. Rats were exposed to a circularly polarized 50 Hz magnetic field at 1 μT for 6 weeks, and the melatonin concentration of blood of separate groups was determined at the end of the exposure and at 1 week and 4 weeks following cessation of exposure. Nocturnal melatonin concentration was reduced (P < 0.05) after 6 weeks of exposure. Melatonin concentration at 1 week following cessation of exposure was normal, and no further change was observed 4 weeks later. © 1994 Wiley‐Liss, Inc.
Search for influence of 1.5 Tesla magnetic field on growth of yeast cells
Authors: Malko J. A. , Constantinidis I. , Dillehay D. , Fajman W. A.
Published: February 2006

We have used a clinical magnetic resonance imager to search for the possible effects of a 1.5 T magnetic fields on the growth of the yeast Saccharomyces cerevisiae. Yeast samples were grown in nutrient broth contained in constant‐temperature boxes, both in and out of the magnetic field of the imager. Growth was measured by using a hemocytometer and light microscope to calculate cell densities. Over the time span corresponding to approximately seven cell divisions, we find no convincing statistical evidence for an effect of magnetic field on cell density. © 1994 Wiley‐Liss, Inc.
Circularly polarized, sinusoidal, 50 Hz magnetic field exposure does not influence plasma testosterone levels of rats
Authors: Kato M. , Honma K. , Shigemitsu T. , Shiga Y.
Published: February 2006

We exposed rats to circularly polarized 50 Hz magnetic fields to determine if plasma testosterone concentration was affected. Previous experiments indicate that magnetic fields suppress the nighttime rise in melatonin, suggesting that other neuroendocrine changes might occur as well. Male Wistar‐King rats were exposed almost continuously for 6 weeks to magnetic flux densities of 1,5, or 50 μT. Blood samples were obtained by decapitation at 12:00 h and 24:00 h. Plasma testosterone concentration showed a significant day‐night difference, with a higher level at 12:00 h when studied in July and December, but the day‐night difference disappeared when concentrations were studied in April. In three experiments, magnetic field exposure had no statistically significant effect on plasma testosterone levels compared with the sham‐exposed groups. These findings indicate that 6 weeks of nearly continuous exposure to circularly polarized, 50 Hz magnetic fields did not change plasma testosterone concentration in rats. © 1994 Wiley‐Liss, Inc.
Power frequency magnetic field exposures among nurses in a neonatal intensive care unit and a normal newborn nursery
Authors: Paul Maureen , Hammond S. Katharine , Abdollahzadeh Sassan
Published: February 2006

Given the current interest in potential carcinogenic and developmental effects of exposure to extremely‐low‐frequency electromagnetic fields, there is a need to identify cohorts of exposed female workers for future epidemiologic investigations. This study was designed to test the hypothesis that nurses working in neonatal intensive care units (NICU) may be significantly exposed to power‐frequency magnetic fields. An electromagnetic field monitor was used to measure magnetic fields at distances of 5, 15, 30, and 60 cm from the surfaces of each device used in the NICU. Six female nurses assigned to the NICU (the “exposed” group) and six female nurses working in the normal newborn nursery (the “referent” group) wore EMDEX dosimeters for the entire duration of their 12 h shifts. An investigator kept a detailed log of each NICU subject's whereabouts for the first one‐third of her shift. Magnetic fields at 5 cm from the front (defined by the nurses' usual work area) of the NICU devices ranged from less than 0.1 to 114 μT and in all cases decreased considerably with increasing distance. The geometric mean of the shift‐time‐weighted average exposure of the NICU nurses was 0.17 μT compared with 0.11 μT for the normal newborn nurses. The percentage of time when subjects were exposed to magnetic fields of 0.4 μT or greater ranged from 5.8% to 15.6% for the NICU nurses, 0.4% to 2.9% for five of the comparison group nurses, and was 9.4% for one of the normal newborn nurses with unidentified aberrantly high exposures. Log data revealed that the vast majority of observed peaks among NICU nurses occurred while subjects were in close proximity to infant bed units. We conclude that NICU nurses represent one female‐intensive job sector with intermittent high exposures to ELF magnetic fields and encourage larger exposure studies of nurses in a variety of medical settings. © 1994 Wiley‐Liss, Inc.
Effects of 2.45‐GHz microwave radiation and phorbol ester 12‐O‐tetradecanoylphorbol‐13‐acetate on dimethylhydrazine‐induced colon cancer in mice
Authors: Wu R. Y. , Chiang H. , Shao B. J. , Li N. G. , Fu Y. D.
Published: February 2006

The purpose of this study was to investigate the effects of 2.45 GHz microwave (MW) radiation on dimethylhydrazine (DMH)‐induced colon cancer in mice. The subjects were 115 Balb/c mice 4 weeks of age. The animals were divided into group A (control), group B (DMH), group C (DMH + MW), and group D [DMH + 12‐O‐tetradecanoylphorbol‐13‐acetate (TPA)]. Radiation (10 mW/cm2) was delivered dorsally with the E field parallel to the mouse's long body axis in an anechoic chamber. Radiations were administered 3 hr daily, 6 days per week, over a period of 5 months. The average SAR was estimated to be 10–12 W/kg. During the course of radiation treatments, DMH was injected once per week. The tumor promoter TPA was administered once per week for 10 weeks, from the third week on, after the initial treatment. The incidence of tumors did not significantly differ between the three test groups (groups B, C, and D; P > 0.25). However, the number of tumors, the size of the tumors, and the incidence of protuberant and infiltrative types in tumor‐bearing animals were higher in group D compared to groups B and C (P < 0.05). No difference was found between groups B and C (P > 0.25). The study indicates that 2.45 GHz microwave radiation at 10 mW/cm2 power density did not promote DMH‐induced colon cancers in young mice. The study also showed that TPA could accelerate colon tumor production if a tumor was initiated. © 1994 Wiley‐Liss, Inc.
Character of the effect of microwave on conduction velocity of frog ventricular muscle
Authors: Yee Kuo Chiang , Chou Chung‐Kwang , Guy Arthur W.
Published: February 2006

Thirty‐two frog hearts were divided into four groups and placed individually in temperature‐controlled waveguides filled with Ringer's solution. The pacemaker was removed, and stimulation was provided at 0.3 Hz by three carbon‐loaded Teflon electrodes located on the aorta and the ventricular muscle. Conduction velocity was measured from the difference between two action potentials. One group served as control; the three other groups were exposed for 2 h to pulsed 2,450 MHz microwave fields (10 μs, 0.001 duty cycle, 16 Hz modulation) at specific absorption rates (SARs) of 0.003, 2, and 6 W/kg, respectively. No significant difference in conduction velocity was found between the control and the exposed groups. © 1994 Wiley‐Liss, Inc.
Dielectric properties of human red blood cells in suspension at radio frequencies
Authors: Lu Yongjun , Yu Jue , Ren Yanhua
Published: February 2006

Dielectric properties of human red blood cells (RBCs) in suspension (hematocrit 50%) from 243 healthy persons (120 males, 123 females) were measured at 25 °C in a frequency range of 1–500 MHz, with a coaxial transmission line reflection method (one‐side measurement). The measuring system, controlled by an IBM‐PC computer, was composed of a network analyzer (HP4195A), an impedance test adapter (HP41951‐61001), a coaxial line sensor, and a temperature‐controlling set. The data measured revealed a statistically significant age dependence, with a critical age of about 49 years, above which permittivity and conductivity of human RBCs in suspension decreased significantly. © 1994 Wiley‐Liss, Inc.
Human exposure to magnetic fields: A comparative assessment of two dosimeters
Authors: Dlugosz Larry , Belanger Kathleen , Johnson Pamela , Bracken Michael B.
Published: February 2006

Two types of dosimeters for measuring human exposure to 60 Hz magnetic fields were compared. Fifty adults wore the single‐axis, wrist model AMEX (average magnetic field exposure system) and the triple axis, hip‐pocket or pouch model AMEX‐3D meters for 2 days. Ninety‐six percent of the tests were accomplished without apparent dosimeter failure. The average root mean square magnetic flux density measurements with the AMEX3D (mean = 0.10 μT, S.D. = 0.07, range = 0.03 − 0.31) were significantly higher than with the AMEX meter (mean = 0.07 μT, S.D. 0.05, range = 0.02 − 0.27 μT) (t test, P < 0.01). There was substantial correlation between the AMEX and the AMEX‐3D measurements (Pearson's correlation coefficient = 0.65, P < 0.01) but poor concordance (Intraclass correlation coefficient = − 0.25). These results suggest that there is a wide variation in exposure to extremely low frequency magnetic fields in the population. Magnetic field measurements with the AMEX‐3D are nearly always higher than with the AMEX dosimeters. Caution is advised when comparing magnetic field measurements made with different types of dosimeters. © 1994 Wiley‐Liss, Inc.
Comments on “trivial influences: A doubly stochastic poisson process model permits the detection of arbitrarily small electromagnetic signals”
Authors: Adair Robert K.
Published: February 2006

I show that Pickard's mathematics cannot properly describe the effects of time‐correlated signals in the presence of incoherent noise and cannot, therefore, properly address most signal‐to‐noise questions. Aside from this objection, I show that Pickard's conclusions follow from an ingenuous definition of “small signals” and do not hold for realistic models of biological processes and more conventional descriptions of “small signals.” © 1995 Wiley‐Liss, Inc.
Ca2+ion transport through patch‐clamped cells exposed to magnetic fields
Authors: Höjevik Per , Sandblom John , Galt Sheila , Hamnerius Yngve
Published: February 2006

The total current of Ca2+ions through patch‐clamped cell membranes was measured while exposing clonal insulin‐producing β‐cells (RINm5F) to a combination of DC and AC magnetic fields at so‐called cyclotron resonance conditions. Previous experimental evidence supports the theory that a resonant interaction between magnetic fields and organisms can exist. This experiment was designed to test one possible site of interaction: channels in the cell membrane. The transport of Ca2+ions through the protein channels of the plasma membrane did not show any resonant behavior in the frequency range studied. © 1995 Wiley‐Liss, Inc.
Hypothesis: The risk of childhood leukemia is related to combinations of power‐frequency and static magnetic fields
Authors: Bowman J. D. , Thomas D. C. , London S. J. , Peters J. M.
Published: February 2006

We present a hypothesis that the risk of childhood leukemia is related to exposure to specific combinations of static and extremely‐low‐frequency (ELF) magnetic fields. Laboratory data from calcium efflux and diatom mobility experiments were used with the gyromagnetic equation to predict combinations of 60 Hz and static magnetic fields hypothesized to enhance leukemia risk. The laboratory data predicted 19 bands of the static field magnitude with a bandwidth of 9.1 μT that, together with 60 Hz magnetic fields, are expected to have biological activity. We then assessed the association between this exposure metric and childhood leukemia using data from a case‐control study in Los Angeles County. ELF and static magnetic fields were measured in the bedrooms of 124 cases determined from a tumor registry and 99 controls drawn from friends and random digit dialing. Among these subjects, 26 cases and 20 controls were exposed to static magnetic fields lying in the predicted bands of biological activity centered at 38.0 μT and 50.6 μT. Although no association was found for childhood leukemia in relation to measured ELF or static magnetic fields alone, an increasing trend of leukemia risk with measured ELF fields was found for subjects within these static field bands (P for trend = 0.041). The odds ratio (OR) was 3.3 [95% confidence interval (CI) = 0.4–30.5] for subjects exposed to static fields within the derived bands and to ELF magnetic field above 0.30 μT (compared to subjects exposed to static fields outside the bands and ELF magnetic fields below 0.07 μT). When the 60 Hz magnetic fields were assessed according to the Wertheimer‐Leeper code for wiring configurations, leukemia risks were again greater with the hypothesized exposure conditions (OR = 9.2 for very high current configurations within the static field bands: 95% CI = 1.3–64.6). Although the risk estimates are based on limited magnetic field measurements for a small number of subjects, these findings suggest that the risk of childhood leukemia may be related to the combined effects of the static and ELF magnetic fields. Further tests of the hypothesis are proposed. © 1995 Wiley‐Liss, Inc.
Specific absorption rate levels measured in a phantom head exposed to radio frequency transmissions from analog hand‐held mobile phones
Authors: Anderson V. , Joyner K. H.
Published: February 2006

Electric fields (E‐fields) induced within a phantom head from exposure to three different advanced mobile phone system (AMPS) hand‐held telephones were measured using an implantable E‐field probe. Measurements were taken in the eye nearest the phone and along a lateral scan through the brain from its centre to the side nearest the phone. During measurement, the phones were positioned alongside the phantom head as in typical use and were configured to transmit at maximum power (600 mW nominal). The specific absorption rate (SAR) was calculated from the in situ E‐field measurements, which varied significantly between phone models and antenna configuration. The SARs induced in the eye ranged from 0.007 to 0.21 W/kg. Metal‐framed spectacles enhanced SAR levels in the eye by 9–29%. In the brain, maximum levels were recorded at the measurement point closest to the phone and ranged from 0.12 to 0.83 W/kg. These SARs are below peak spatial limits recommended in the U.S. and Australian national standards [IEEE Standards Coordinating Committee 28 (1991): C95.1‐1991 and Standards Australia (1990): AS2772.1‐1990] and the IRPA guidelines for safe exposure to radio frequency (RF) electromagnetic fields [IRPA (1988): Health Phys 54:115–123]. Furthermore, a detailed thermal analysis of the eye indicated only a 0.022°C maximum steady‐state temperature rise in the eye from a uniform SAR loading of 0.21 W/kg. A more approximate thermal analysis in the brain also indicated only a small maximum temperature rise of 0.034°C for a local SAR loading of 0.83 W/kg. © 1995 Wiley‐Liss, Inc.
Pulsed magnetic field from video display terminals enhances teratogenic effects of cytosine arabinoside in mice
Authors: Chiang H. , Wu R. Y. , Shao B. J. , Fu Y. D. , Yao G. D. , Lu D. J.
Published: February 2006

Eighty‐nine Swiss Webster mice were randomly divided into four groups: a control group, a pulsed magnetic field (PMF) group, a cytosine arabinoside (ara‐C, a teratogen) group, and, a combined PMF + ara‐C group. Mice in the PMF and PMF + ara‐C groups were irradiated with a PMF (a sawtooth waveform with 52 μs rise time, 12 μs decay time, and 15.6 kHz frequency) at a peak magnetic flux density of 40 μT for 4 hours daily on days 6–17 of gestation. The mice in the ara‐C and the PMF + ara‐C groups were injected intraperitoneally on day 9 of gestation with 10 mg/kg of ara‐C. The incidence of resorption and dead fetuses was not affected by PMF but was increased by ara‐C injection. The malformation incidence of cleft palate (CP) and/or cleft lip (CL) was significantly higher in all three of the treated groups than in the control group (P < 0.05). If, however, statistical analyses had been done on litters rather than on individual fetuses, they would show that the incidence of CP and/or CL in the PMF group is not significantly greater than that in the control group. A significantly higher incidence of CP and/or CL was found in the PMF + ara‐C group (49%) than the ara‐C alone group (26.1%). These data suggest that PMF might enhance the development of ara‐C‐induced CP and/or CL. The incidence of minor variations in skeletal development, including reduction of skeletal calcification and loss of skeleton, was not statistically significant in the PMF group. However, it was higher in the two ara‐C‐treated groups, and there was no significant difference between the ara‐C alone group and the ara‐C + PMF group. From these results it is concluded that the very weak embryotoxic effects of PMF exposure may be revealed and enhanced in combination with a teratogenic agent. © 1995 Wiley‐Liss, Inc.
Childhood cancer in relation to indicators of magnetic fields from ground current sources
Authors: Wertheimer Nancy , Savitz David A. , Leeper Ed
Published: February 2006

This study examines childhood cancer risk in relation to certain factors likely to indicate magnetic field exposure from ground currents in the home. Substantial ground currents are most often found in homes having conductive plumbing, in which an uninterrupted metallic path in the water pipes and water main connects the grounding systems of neighboring houses. Information on plumbing conductivity was obtained from water suppliers for the homes of 347 cases and 277 controls identified in an earlier study of magnetic field exposure and childhood cancer in the Denver area. An increased cancer risk was observed for children in homes with conductive plumbing: The matched odds ratio was 1.72 (1.03–2.88) and increased to 3.00 (1.33–6.76) when analysis was limited to cases and controls who were residentially stable from the reference date to the study date. A measurement metric likely to indicate active ground currents (measurements having above‐median intensity and a nonvertical orientation of <55° from the horizontal) was identified. In contrast to measured field intensity alone, for which only modest associations with cancer have been reported, this metric shows a high and significant cancer risk [matched O.R. = 4.0 (1.6–10.0)] consistent over a range of intensity and angle cutpoints. Such elevated nonvertical fields were also associated with cancer in an independent data set, which was gathered to study adult nonlymphocytic leukemia in the Seattle area. The associations of cancer with conductive plumbing and with this exposure metric both suggest that cancer risk is increased among persons with elevated magnetic field exposure from residential ground currents. © 1995 Wiley‐Liss, Inc.
Recovery characteristics of a rigid, nonmetallic microdialysis probe for use in an electromagnetic field
Authors: Mason P. A. , Romano W. F.
Published: February 2006

It is well known that metal objects perturb electromagnetic fields. Therefore, a conventional metal microdialysis probe cannot be used to determine the bioeffects of electromagnetic radiation. Using fused‐silica tubing, we developed an inexpensive nonmetallic, rigid microdialysis probe for use in electromagnetic radiation research or during magnetic resonance imaging. This probe has a concentric tube design, with the membrane length adjustable to the size of the area to be dialyzed. The probes tested had regenerated‐cellulose membranes that were 3 mm in length. This report describes how to make this probe. Average relative recovery rates at flow rates of 2.0, 1.0, and 0.5 μl/min were 21%, 27%, and 42%, respectively. These rates were slightly lower than the 30%, 42%, and 68% obtained with the commercially available metallic CMA10 microdialysis probe with a 3 mm membrane. This may be due to the fused‐silica probe and CMA10 probe being made with different types of dialysis membranes. © 1995 Wiley‐Liss, Inc.
Melatonin and puberty in female lambs exposed to EMF: A replicate study
Authors: Lee J. M. , Stormshak F. , Thompson J. M. , Hess D. L. , Foster D. L.
Published: February 2006

In an earlier study, we found no effects of 60 Hz electric and magnetic fields (EMF) from a 500 kV transmission line on serum melatonin patterns or on puberty in ten female Suffolk lambs (Ovis aries). We conducted a larger replicate study of 15 lambs exposed to a mean electric field of 6.3 kV/m and a mean magnetic field of 3.77 μT and 15 controls exposed to EMF two orders of magnitude weaker than in the line area. The replicate produced essentially the same results as our previous study. © 1995 Wiley‐Liss, Inc.
Millimeter microwave effect on ion transport across lipid bilayer membranes
Authors: Alekseev S. I. , Ziskin M. C.
Published: February 2006

The effects of millimeter microwaves in the frequency range of 54–76 GHz on capacitance and conductance of lipid bilayer membranes (BLM) were studied. Some of the membranes were modified by gramicidin A and amphotericin B or by tetraphenylboron anions (TPhB−). The millimeter microwaves were pulse‐modulated (PW) at repetition rates ranging from 1 to 100 pps, PW at 1000 pps, or unmodulated continuous waves (CW). The maximum output power at the waveguide outlet was 20 mW. It was found that CW irradiation decreased the unmodified BLM capacitance by 1.2% ± 0.5%. At the same time, membrane current induced by TPhB transport increased by 5% ± 1%. The changes in conductance of ionic channels formed by gramicidin A and amphotericin B were small (0.6% ± 0.4%). No “resonance‐like” effects of mm‐wave irradiation on membrane capacitance, ionic channel currents, or TPhB transport were detected. All changes in membrane capacitance and currents were independent of the modulation employed and were equivalent to heating by approximately 1.1 °C. © 1995 Wiley‐Liss, Inc.
Measurement and analysis of static magnetic fields that block action potentials in cultured neurons
Authors: Cavopol A. V. , Wamil A. W. , Holcomb R. R. , McLean M. J.
Published: February 2006

To characterize the properties of static magnetic fields on firing of action potentials (AP) by sensory neurons in cell culture, we developed a mathematical formalism based on the expression for the magnetic field of a single circular current loop. The calculated fields fit closely the field measurements taken with a Hall effect gaussmeter. The biological effect induced by different arrays of permanent magnets depended principally on the spatial variation of the fields, quantified by the value of the gradient of the field magnitude. Magnetic arrays of different sizes (macroarray: four center‐charged neodymium magnets of ˜14 mm diameter; microarray: four micromagnets of the same material but of ˜0.4 mm diameter) allowed comparison of fields with similar gradients but different intensities at the cell position. These two arrays had a common gradient value of ˜1 mT/mm and blocked >70% of AP. Alternatively, cells placed in a field strength of ˜0.2 mT and a gradient of ˜0.02 mT/mm produced by the macroarray resulted in no significant reduction of firing; a microarray field of the same strength but with a higher gradient of ˜1.5 mT/mm caused ˜80% AP blockade. The experimental threshold gradient and the calculated threshold field intensity for blockade of action potentials by these arrays were estimated to be ˜0.02 mT/mm and −0.02 mT, respectively. In conclusion, these findings suggest that spatial variation of the magnetic field is the principal cause of AP blockade in dorsal root ganglia in vitro. © 1995 Wiley‐Liss, Inc.
Magnetic field exposure among utility workers
Authors: Bracken T. Dan , Rankin Richard F. , Senior Russell S. , Alldredge J. Richard , Sussman Stanley S.
Published: February 2006

The Electric and Magnetic Field Measurement Project for Utilities—the Electric Power Research Institute (EPRI) Electric and Magnetic Field Digital Exposure (EMDEX) Project (the EPRI EMDEX Project)—was a multifaceted project that entailed technology transfer, measurement protocol design, data management, and exposure assessment analyses. This paper addresses one specific objective of the project: the collection, analysis, and documentation of power‐frequency magnetic field exposures for a diverse population of utility workers. Field exposure data measured by an EMDEX system were collected by volunteer utility employees at 59 sites in four countries between September, 1988, and September, 1989. Specially designed sampling procedures and data collection protocols were used to ensure uniform implementation across sites. Volunteers within 13 job classifications recorded which of eight work or three nonwork environments they occupied while wearing an EMDEX meter. Approximately 50,000 hours of magnetic field exposure records taken at 10 s intervals were obtained, about 70% of which were from work environments. Exposures and time spent in environments were analyzed by primary work environment, by occupied environment, and by job classification. Generally, for utility‐specific job classifications related to the generation, transmission, and distribution of electricity, the field and exposure measurements in terms of workday mean field were higher than in more general occupations. The job classifications with the highest (median workday mean) exposure were substation operators (0.7 μT) and electricians (0.5μT). Total variance also tended to be largest for utility‐specific job classifications. For these workers, the contributions of between‐worker and within‐worker variances to total variance were about the same. Measurements in utility‐specific environments were higher than in more general environments. Estimates of time‐integrated exposure indicated that utility‐specific job classifications received about one‐half or more of their total exposure on the job. The nonwork field and exposure distributions for workers in all job categories were comparable with median nonworkday means of about 0.09 μT. © 1995 Wiley‐Liss, Inc.
Microwave influence on the isolated heart function: I. Effect of modulation
Authors: Pakhomov Andrei G. , Dubovick Boris V. , Degtyariov Igor G. , Pronkevich Anatoly N.
Published: February 2006

Dependence of the microwave effect on modulation parameters (pulse width, duty ratio, and peak intensity) was studied in an isolated frog auricle preparation. The rate and amplitude of spontaneous auricle twitches were measured during and after a 2 min exposure to 915 or 885 MHz microwaves and were compared to preexposure values. The studied ranges of modulation parameters were: pulse width, 10−6–10−2 s; duty ratio, 7:100000, and peak specific absorption rate, 100‐3000 W/kg. Combinations of the parameters were chosen by chance, and about 400 various exposure regimes were tested. The experiments established that no regime was effective unless the average microwave power was high enough to induce preparation heating (0.1–0.4°C). The twitch rate instantly increased, and the amplitude decreased, as the temperature rose; similar changes could be induced by equivalent conventional heating. The data provide evidence that the effect of short‐term microwave exposure on the isolated heart pacemaker and contractile functions depends on pulse modulation just as much as modulation determines the average absorbed power. These functions demonstrated no specific dependence on exposure parameters such as frequency or power windows. © 1995 Wiley‐Liss, Inc.
Membrane potential perturbations induced in tissue cells by pulsed electric fields
Authors: Cooper Mark S.
Published: February 2006

Pulsed electric fields directly influence the electrophysiology of tissue cells by transiently perturbing their transmembrane potential. To determine the magnitude and time course of this interaction, electrotonic cable theory was used to calculate the membrane potential perturbations induced in tissue cells by a spatially uniform, pulsed electric field. Analytic solutions were obtained that predict shifts in membrane potential along the length of cells as a function of time in response to an electrical pulse. For elongated tissue cells, or groups of tissue cells that are coupled electrotonically by gap junctions, significant hyperpolarizations and depolarizations can result from millisecond applications of electric fields with strengths on the order of 10–100 mV/cm. The results illustrate the importance of considering cellular cable parameters in assessing the effects of transient electric fields on biological systems, as well as in predicting the efficacy of pulsed electric fields in medical treatments. © 1995 Wiley‐Liss, Inc.
Neurochemical effects of a 20 kHz magnetic field on the central nervous system in prenatally exposed mice
Authors: Dimberg Yvonne
Published: February 2006

C57/B1 mice were exposed during pregnancy (gestation days 0–19) to a 20 kHz magnetic field (MF). The asymmetric sawtooth‐wave form magnetic field in the exposed racks had a flux density of 15 μT (peak to peak). After 19 days, the exposure was terminated, and the mice were housed individually under normal laboratory conditions. On postnatal day (PD) 1, PD21, and PD308, various neurochemical markers in the brains of the offspring were investigated and the brains weighed. No significant difference was found in the whole brain weight at PD1 or PD21 between exposed offspring and control animals. However, on PD308, a significant decrease in weight of the whole brain was detected in exposed animals. No significant differences were found in the weight of cortex, hippocampus, septum, or cerebellum on any of the sampling occasions, nor were any significant differences detected in protein‐, DNA‐level, nerve growth factor (NGF), acetylcholine esterase‐ (AChE), or 2′,3′‐cyclic nucle‐otide 3′‐phosphodiesterase‐ (CNP; marker for oligodendrocytes) activities on PD21 in cerebellum. Cortex showed a more complex pattern of response to MF: MF treatment resulted in a decrease in DNA level and increases in the activities of CNP, AChE, and NGF protein. On PD308, the amount of DNA was significantly reduced in MF‐treated cerebellum and CNP activity was still enhanced in MF‐treated cortex compared to controls. Most of the effects of MF treatment during the embryonic period were similar to those induced by ionizing radiation but much weaker. However, the duration of the exposure required to elucidate the response of different markers to MF seems to be greater and effects appear later during development compared to responses to ionizing radiation. © 1995 Wiley‐Liss, Inc.
Effects of 50 Hz magnetic fields on C‐myc transcript levels in nonsynchronized and synchronized human cells
Authors: Desjobert Hélène , Hillion Josette , Adolphe Monique , Averlant Geneviève , Nafziger Joëlle
Published: February 2006

The effects of 50 Hz electromagnetic fields (EMFs) on the expression of the c‐myc oncogene, known to be involved in normal cell proliferation and possibly also in tumor processes, were investigated in nonsynchronized human lymphoid cells immortalized by Epstein‐Barr virus. Viral injury to such cells makes them a good model for exploring the possible cancer‐promoting effects of 50 Hz magnetic fields. Parallel experiments were conducted on human HL60 leukemic cells. Cells were exposed to sinusoidal 50 Hz EMFs at 10 μT or 1 mT for 20 min, 1 h, 24 h, or 72 h. Exposure was performed either immediately after refeeding or 1.5 h after refeeding. C‐myc transcript values were assessed by Northern blot analysis and normalized to those of the noninducible gene GaPDH. No statistically significant difference between the c‐myc transcript levels of control and exposed cells was found in lymphoid or leukemic cells under our experimental conditions, either after short exposures of 20 min and 1 h or after longer exposures of 24 and 72 h. Other experiments were carried out with pseudosynchronized cells in an attempt to establish whether cells were especially sensitive to 50 Hz magnetic field exposure in any particular phase of the cell cycle. Accordingly, cells were pseudosynchronized in G0/G1 by serum deprivation and exposed for 20 min to a 50 Hz magnetic field, at 10 μT for lymphoid cells and 1 mT for HL60 cells. No significant difference was observed between the c‐myc transcript levels of control and exposed cells for either of the synchronized cell types. These results for synchronized cells correlated with those for nonsynchronized cells. © 1995 Wiley‐Liss, Inc.
Exposure to oscillating magnetic fields influences sensitivity to electrical stimuli. I. experiments on pigeons
Authors: Seppia Cristina Del , Ghione Sergio , Luschi Paolo , Papi Floriano
Published: February 2006

The comparison of two measurements of the pigeon threshold for electrical stimuli, performed 2 h apart, reveals stress‐induced analgesia as a result of stressful manipulations between the two tests. When pigeons are exposed to a weak, oscillating magnetic field between the two measurements, the analgesic response is inhibited and a hyperalgesic effect is recorded. The present findings are in agreement with previous studies showing that magnetic treatments may alter pigeons' emotional state and some of their behavioral patterns. © 1995 Wiley‐Liss, Inc.
Exposure to oscillating magnetic fields influences sensitivity to electrical stimuli. II. experiments on humans
Authors: Papi Floriano , Ghione Sergio , Rosa Caterina , Seppia Cristina Del , Luschi Paolo
Published: February 2006

To assess the effect of a magnetic treatment on pain perception, we compared the sensory threshold in 18 healthy volunteers. We determined the threshold by noninvasive electrical stimulation of the tooth pulp and skin before and after exposure to an altered magnetic field of low intensity and to a sham treatment. Five different parameters were recorded: the sensory and pain thresholds for the tooth and the sensory, pain, and tolerance thresholds for the skin. Two hours of exposure to a weak, oscillating magnetic field induced a significant decrease in three parameters (dental sensory and cutaneous pain and tolerance thresholds), whereas the other two parameters showed a similar tendency. When the same subjects were exposed to a sham treatment, only marginal, nonsignificant variations in all parameters were observed. These results represent the first piece of evidence that weak alterations of the magnetic field may induce hyperalgesia in humans. © 1995 Wiley‐Liss, Inc.
Failure to produce taste‐aversion learning in rats exposed to static electric fields and air ions
Authors: Creim J. A. , Lovely R. H. , Weigel R. J. , Forsythe W. C. , Anderson L. E.
Published: February 2006

Taste‐aversion (TA) learning was measured to determine whether exposure to high‐voltage direct current (HVdc) static electric fields can produce TA learning in male Long Evans rats. Fifty‐six rats were randomly distributed into four groups of 14 rats each. All rats were placed on a 20 min/day drinking schedule for 12 consecutive days prior to receiving five conditioning trials. During the conditioning trials, access to 0.1 % sodium saccharin‐flavored water was given for 20 min, followed 30 min later by one of four treatments. Two groups of 14 rats each were individually exposed to static electric fields and air ions, one group to +75 kV/m (+2 × 105 air ions/cm3) and the other group to −75 kV/m (‐2 × 105 air ions/cm3). Two other groups of 14 rats each served as sham‐exposed controls, with the following variation in one of the sham‐exposed groups: This group was subdivided into two subsets of seven rats each, so that a positive control group could be included to validate the experimental design. The positive control group (n = 7) was injected with cyclophosphamide 25 mg/kg, i.p., 30 min after access to saccharin‐flavored water on conditioning days, whereas the other subset of seven rats was similarly injected with an equivalent volume of saline. Access to saccharin‐flavored water on conditioning days was followed by the treatments described above and was alternated daily with water “recovery” sessions in which the rats received access to water for 20 min in the home cage without further treatment. Following the last water‐recovery session, a 20 min, two‐bottle preference test (between water and saccharin‐flavored water) was administered to each group. The positive control group did show TA learning, thus validating the experimental protocol. No saccharin‐flavored water was consumed in the two‐bottle preference test by the cyclophosphamide‐injected, sham‐exposed group compared to 74% consumed by the saline‐injected sham‐exposed controls (P <.0001). Saccharin‐preference data for the static field‐exposed groups showed no TA learning compared to data for sham‐exposed controls. In summary, exposure to intense static electric fields and air ions did not produce TA learning as assessed by this particular design. © 1995 Wiley‐Liss, Inc.
Do ELF magnetic fields affect human reaction time?
Authors: Podd John V. , Whittington Craig J. , Barnes Geoffrey R. G. , Page Wyatt H. , Rapley Bruce I.
Published: February 2006

Two double‐blind studies were run in an attempt to confirm the finding that a 0.2 Hz magnetic field affects simple reaction time (RT) in humans, whereas a 0.1 Hz field does not. In the first experiment, 12 volunteer subjects were exposed to a continuous 0.2 Hz, 0.1 Hz, or sham field in a fully counter‐balanced, within‐subjects design. Subjects were run singly for one condition each day over 3 consecutive days with a field strength of 1.1 mT and a daily exposure duration of 5 min. Neither magnetic field had any effect on RT at any time during the exposure. One condition of a second study, using a new group of 24 volunteer subjects, also failed to find any field effects at 0.2 Hz. Additionally, the second study failed to show any effects when the frequency, flux density, and field orientation were set according to parametric resonance theory. It is suggested that, although ELF magnetic field effects on human behaviour may be elusive, future research can improve detection rates by paying greater attention to reducing error variance and increasing statistical power. © 1995 Wiley‐Liss, Inc.
Effect of magnetic fields on rodent monooxygenase enzymes
Authors: Carratore R. Del , Morichetti E. , Della Croce C. , Bronzetti G.
Published: February 2006

The effects of 50 Hz, 1.2 mT magnetic fields (MFs) were tested on hepatic monooxygenase enzymes of basal and β‐naphthoflavone‐phenobarbital‐preinduced rats and mice. An inductive effect on cytochrome P‐450 level and on some enzymatic cytochrome P‐450‐dependent activities was observed in basal mice after MF exposure. Enzymatic activities in preinduced mice and rats were reduced by MFs, the degree of reduction depending on the enzyme. A specific inhibitory effect was determined in some of the assayed activities and in the relative peculiar P‐450 isoforms detected by Western blot analysis. © 1995 Wiley‐Liss, Inc.
Effects of 50 Hz magnetic fields on mouse spermatogenesis monitored by flow cytometric analysis
Authors: De Vita Raffaele , Cavallo Delia , Raganella Luigi , Eleuteri Patrizia , Grollino Maria G. , Calugi Alberto
Published: February 2006

Flow cytometry (FCM) was performed to monitor the cellular effects of extremely‐low‐frequency magnetic field on mouse spermatogenesis. Groups of five male hybrid F1 mice aged 8–10 weeks were exposed to 50 Hz magnetic field. The strength of the magnetic field was 1.7 mT. Exposure times of 2 and 4 h were chosen. FCM measurements were performed 7, 14, 21, 28, 35, and 42 days after treatment. For each experimental point, a sham‐treated group was used as a control. The possible effects were studied by analyzing the DNA content distribution of the different cell types involved in spermatogenesis and using the elongated spermatids as the reference population. The relative frequencies of the various testicular cell types were calculated using specific software. In groups exposed for 2 h, no effects were observed. In groups exposed for 4 h, a statistically significant (P < 0.001) decrease in elongated spermatids was observed at 28 days after treatment. This change suggests a possible cytotoxic and/or cytostatic effect on differentiating spermatogonia. However, further studies are being carried out to investigate the effects of longer exposure times. © 1995 Wiley‐Liss, Inc.
Biologic effects of prolonged exposure to ELF electromagnetic fields in rats: II. 50 Hz magnetic fields
Authors: Margonato V. , Nicolini P. , Conti R. , Zecca L. , Veicsteinas A. , Cerretelli P.
Published: February 2006

To provide possible laboratory support to health risk evaluation associated with long‐term, low‐intensity magnetic field exposure, 256 male albino rats and an equal number of control animals (initial age 12 weeks) were exposed 22 h/day to a 50 Hz magnetic flux density of 5 μmT for 32 weeks (a total of about 5000 h). Hematology was studied from blood samples before exposure to the field and at 12 week intervals. Morphology and histology of liver, heart, mesenteric lymph nodes, and testes as well as brain neurotransmitters were assessed at the end of the exposure period. In two identical sets of experiments, no significant differences in the investigated variables were found between exposed and sham‐exposed animals. It is concluded that continuous exposure to a 50 Hz magnetic field of 5 μT from week 12 to week 44, which makes up ˜70% of the life span of the rat before sacrifice, does not cause changes in growth rate, in the morphology and histology of liver, heart, mesenteric lymph nodes, testes, and bone marrow, in hematology and hematochemistry, or in the neurotransmitters dopamine and serotonin. © 1995 Wiley‐Liss, Inc.
Sinusoidal 50 Hz 500 μT magnetic field has no acute effect on urinary 6‐sulphatoxymelatonin in wistar rats
Authors: Bakos József , Nagy Noémi , Thuróczy György , Szabó László D.
Published: February 2006

The effect of a 50 Hz, vertical magnetic field on the excretion of urinary 6‐sulphatoxymelatonin (aMT6s) of male and female Wistar rats was studied in a self‐controlled experiment. Twenty rats were kept in metabolic cages under 9:15 h light:dark conditions. The urine of the animals was collected twice per day for 5 consecutive days. The concentration of aMT6s in the rat urine was measured by 125I radioimmunoassay. The rats were exposed to 5 and 500 μT flux density for 24 h. The excretion of urinary aMT6s did not show significant changes during or after magnetic field exposure. © 1995 Wiley‐Liss, Inc.
Action of 50 Hz magnetic fields on cyclic AMP and intercellular communication in monolayers and spheroids of mammalian cells
Authors: Schimmelpfeng Jutta , Stein Johannes‐Christoph , Dertinger Hermann
Published: February 2006

To investigate the influence of physiological parameters such as cell density and three‐dimensional cell contact on the biological action of a 2 mT/50 Hz magnetic field, mouse fibroblasts were exposed as monolayers and as multicellular spheroids. Changes in cyclic AMP content of cells and alterations in gap junction‐mediated intercellular communication were measured immediately after 5 min of exposure to the field. In monolayers of intermediate cell density (1 × 105 cells/cm2), the field treatment caused an increase in cAMP to 121% of the control level, whereas, at 3 × 105 cells/cm2 (near confluence), a decrease to 88% of the unexposed cells was observed. Furthermore, field exposure stimulated gap‐junction communication to 160% of the control level as determined by Lucifer yellow dye exchange. In spheroids, alterations in the radial profile of cellular cAMP were observed that were due both to field‐induced local cAMP changes and to increased gap‐junction permeability for this second messenger, the latter causing radial cAMP gradients to be flattened. The results indicate a strong dependence of field action on physiological parameters of the system exposed. © 1995 Wiley‐Liss, Inc.