bluuebunny/crossref_metadata_2025 huggingface dataset:
Diurnal patterns in brain biogenic amines of rats exposed to 60‐Hz electric fields
Authors: Vasquez Beatriz J. , Anderson Larry E. , Lowery Carolyn I. , Adey W. Ross
Published: February 2006

Levels of brain neurotransmitters and their metabolites, as well as concentrations of enzymes associated with their synthesis and metabolism, fluctuate during the day in patterns defined as circadian. The present study examined these rhythms in albino rats exposed to 60‐Hz electric fields. Thirty‐six animals were exposed to a 39 kV/m field for 4 weeks, 20 h/day, in a parallel‐plate electrode system. A group of 36 sham animals was similarly handled and housed in a nonenergized exposure system. On the sampling day, animals were sacrificed at 4‐h intervals throughout the 24‐h day. Brains were removed, dissected, and kept frozen until chemically analyzed. The levels of biogenic amines and their acidic metabolites in the striatum, hypothalamus, and hippocampus were determined by high‐performance liquid chromatography with electrochemical detection (HPLC‐ECD) methods. Repeated exposure to 60‐Hz electric fields produced significant alterations in the diurnal rhythms of several biogenic amines: dihydroxyphenylacetic acid (DOPAC, the primary metabolite of dopamine in the rat) in the striatum, and norepinephrine, dopamine, and 5‐hydroxyindoleacetic acid (5‐HIAA; serotonin metabolite) in the hypothalamus. Levels of serotonin in the striatum and hypothalamus showed clear circadian patterns that was not affected by the field. No diurnal or field‐related changes were observed in the hippocampal amines.
Effects of 2.45‐GHz microwave and 100‐MHz radiofrequency radiation on liposome permeability at the phase transition temperature
Authors: Liu Li‐Ming , Cleary Stephen F.
Published: February 2006

Large unilamellar dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphos‐phatidylglycerol (DPPG) liposomes loaded with an aqueous chemotherapeutic drug, cytosine arabinofuranoside (ARA‐C), were exposed for 30 min to 60 W/kg continuous‐wave (CW) 100‐MHz or 2.45‐GHz radiation in vitro at temperatures between 37 °C and 43 °C. Liposomes were exposed in HEPES buffer or in HEPES buffer supplemented with 44% by volume fetal calf serum (FCS). Characteristic phase transition responses were detected in the range of 39 °C to 40 °C with the presence of FCS, increasing maximum % release of 3H‐ARA‐C by 20% relative to HEPES suspension. Neither frequency of electromagnetic radiation had any detectable effect on liposome permeability or the location of the phase transition in the presence or absence of FCS.
Resonant AC‐DC magnetic fields: Calculated response
Authors: Durney Carl H. , Rushforth Craig K. , Anderson Allen A.
Published: February 2006

An elementary model consisting of one charged particle in a viscous medium exposed to weak ac‐dc low‐frequency magnetic fields is analyzed to identify and explain the fundamental characteristics of the physical mechanisms that result in a resonance response, which is similar to the familiar cyclotron resonance. The model predicts both frequency and amplitude windows, which are explained in terms of synchronization of the particle with electric fields. Although extrapolation of model results to biological systems is limited by the elementary nature of the model, the model results indicate that observed resonant responses by others of biological systems to ac‐dc magnetic fields are probably not due to resonant response of ions in solution, since the model predicts that no resonant response is possible unless the viscous damping is very low, many orders of magnitude lower than the viscous damping of ions in solution.
Acute low‐level microwave exposure and central cholinergic activity: Studies on irradiation parameters
Authors: Lai Henry , Horita Akira , Guy Arthur W.
Published: February 2006

Sodium‐dependent high‐affinity choline uptake was measured in the striatum, frontal cortex, hippocampus, and hypothalamus of rats after acute exposure (45 min) to pulsed (2 μs, 500 pps) or continuous‐wave 2, 450‐MHz microwaves in cylindrical waveguides (Guy et al.: Radio Science 14:63–74, 1979) or miniature anechoic chambers (Guy: Journal of Microwave Power 14:327–338, 1979). In all exposure conditions, the average whole‐body specific absorption rate was at 0.6 W/kg. Decrease in choline uptake was observed in the frontal cortex after microwave exposure in all of the above irradiation conditions. Regardless of the exposure system used, hippocampal choline uptake was decreased after exposure to pulsed but not continuous‐wave microwaves. Striatal choline uptake was decreased after exposure to either pulsed or continuous‐wave microwaves in the miniature anechoic chamber. No significant change in hypothalamic choline uptake was observed under any of the exposure conditions studied. We conclude that depending on the parameters of the radiation, microwaves can elicit specific and generalized biological effects.
Analysis of electric and magnetic fields leaking from induction heaters
Authors: Andreuccetti D. , Bini M. , Ignesti A. , Olmi R. , Rubino N. , Vanni R.
Published: February 2006

Results are presented of an investigation on electric and magnetic fields leaking from inductive (magnetic) heaters that are used for thermal processing of high‐power electron tubes and lasers in an industrial plant. Measurements of electric and magnetic fields were done using both commercially available and laboratory‐developed instrumentation. Isotropic H‐field sensors were developed to allow quantitative evaluation of high‐intensity magnetic fields. Ten induction heaters with nominal A.C. power ranging from 2.5 kW to 15 kW and operating at frequencies between 300 kHz and 790 kHz were surveyed. Electric field strengths up to 8 kV/m and magnetic field strengths up to 20 A/m were measured.
On the cyclotron resonance mechanism for magnetic field effects on transmembrane ion conductivity
Authors: Halle Bertil
Published: February 2006

The cyclotron resonance model, recently proposed to account for physiological response to weak environmental magnetic fields, is shown to violate the laws of classical mechanics. Further, it is argued that the ubiquitous presence of dynamic friction in fluid media precludes significant magnetic effects on membrane ion transport.
Lithium as a normal metabolite: Some implications for cyclotron resonance of ions in magnetic fields
Authors: Smith Robert F.
Published: February 2006

Cyclotron resonance of ions has been proposed as a mechanism by which weak, extremely‐low‐frequency (ELF) electromagnetic fields can act on biological systems. Critics of a mechanism predicated on resonance of lithium have argued that this element is virtually absent from the internal milieu of mammals and otherwise plays no role in the normal physiological functioning of the organism. Sophisticated techniques of trace‐element analysis have recently revealed that lithium is a normal constituent of tissues of assayed mammals, including those of rats and human beings. There is evidence, too, that lithium is an important, biologically‐active element. Cyclotron resonance may or may not be a mechanism by which ELF‐ and static‐magnetic fields at low strengths combine to affect the organism, but rejection of this mechanism on the grounds that lithium is absent or is physiologically inadequate is unwarranted. Lithium is normally present and is metabolically active in many tissues, especially those of the of the neuroendocrine system.
Statistical approach to combining the results of similar experiments, with application to the hematologic effects of extremely‐low‐frequency electric field exposures
Authors: Morris M. D. , Kimball K. T. , Aldrich T. E. , Easterly C. E.
Published: February 2006

A large proportion of scientific effort in investigating the possible biological effects of exposure to extremely‐low‐frequency (ELF) fields consists of laboratory studies on experimental animals. Most experiments in which hematologic properties are measured show no statistically significant effect due to exposure. However, some studies show significant effects which, in general, are not clearly reproducible. A difficult question must then be addressed: Are these relatively few indications of ELF effects statistical artifacts due to the increased risk of a type I error in multiple studies, or is there a real biological effect that is undetected in most studies due to the relatively small sample sizes commonly used? A statistical approach for examining the accumulated results of multiple experiments which results in a single test for treatment effect is presented. The technique requires very mild assumptions, and is valid for experiments that vary widely in specific characteristics such as exposure level, duration, and laboratory. The method is applied to the results of a collection of hematologic and serum chemistry experiments, and the combined results indicate the existence of experimental effects on some end points.
ELF electromagnetic environment in power substations
Authors: Hayashi N. , Isaka K. , Yokoi Y.
Published: February 2006

This paper presents a theoretical analysis of electromagnetic environments in power substations in service. A new analytical method is developed and applied to magnetic field calculations in 187‐kV and 66‐kV substations. Experimental results verify that the method offers a good prediction of the magnetic field profiles in the substations except for the areas where localized field sources exist. The analytical results show that the magnetic field strength depends to a great extent on how the load powers distribute on individual lines and buses, that the magnetic fields in substations have a three‐dimensional characteristic, and that the predominant field component depends on the position of interest. Moreover, it is suggested that objects placed in substations are exposed not only to magnetic fields of high strength in comparison to those in houses or near the distribution networks but also to fields with several percent of harmonic distortion.
Lack of behavioral effects in the rhesus monkey: High peak microwave pulses at 1.3 GHz
Authors: D'Andrea John A. , Cobb Brenda L. , de Lorge John O.
Published: February 2006

The current safety standards for radiofrequency and microwave exposure do not limit the peak power of microwave pulses for general or occupational exposures. While some biological effects, primarily the auditory effect, depend on pulsed microwaves, hazards associated with very high peak‐power microwave pulses in the absence of whole‐body heating are unknown. Five rhesus monkeys, Macaca mulatta, were exposed to peak‐power densities of 131.8 W/cm2 (RMS) while performing a time‐related behavioral task. The task was composed of a multiple schedule of reinforcement consisting of three distinct behavioral components: inter‐response time, time discrimination, and fixed interval. Trained monkeys performed the multiple schedule during exposure to 1.3‐GHz pulses at low pulse‐repetition rates (2–32 Hz). No significant change was observed in any behavior during irradiation as compared to sham‐irradiation sessions. Generalization of these findings to experimental results with higher peak‐power densities, other pulse rates, different carrier frequencies, or other behaviors is limited.
Addition of magnetic field capability to existing extremely‐low‐frequency electric field exposure systems
Authors: Miller D. L. , Miller M. C. , Kaune W. T.
Published: February 2006

Magnetic field systems were added to existing electric field exposure apparatuses for exposing cell suspensions in vitro and small animals in vivo. Two horizontally oriented, rectangular coils, stacked one directly above the other, have opposite electric currents. This configuration minimizes leakage fields and allows sham‐ and field‐exposure systems to be placed in the same room or incubator. For the in vitro system, copper plates formed the loop‐pair, with up to 900 A supplied by a 180:1 transformer. Electric fields were supplied via electrodes at the ends of cell‐culture tubes, eight of which can be accommodated by each exposure system. Two complete systems are situated in an incubator to allow simultaneous sham and field exposure up to 1 mT. For the in vivo system, four pairs of 0.8 × 2.7‐m coils made of copper bus bar are employed. This arrangement is energized from the power grid via a 30:1 transformer; horizontal magnetic flux densities up to 1 mT can be generated. Pairs of electrode plates spaced 30.5 cm apart provide electric field exposure of up to 130 kV/m. Four systems with a capacity of 48 rats each are located in one room. For both the in vitro and in vivo systems, magnetic exposure fields are uniform to within ± 2.5%, and sham levels are at least 2,500‐fold lower than exposure levels. Potential confounding factors, such as heating and vibration, were examined and found to be minimal.
Intensity threshold for 60‐hz magnetically induced behavioral changes in rats
Authors: Liboff Abraham R. , Thomas John R. , Schrot John
Published: February 2006

Experiments were conducted to further investigate the effect of 60‐Hz cyclotron‐resonance exposures on rats performing on a multiple FR‐DRL schedule. The previously reported temporary loss of DRL baseline response, when measured as a function of A.C. magnetic intensity, was found to have a threshold. Utilizing the component of A.C. magnetic intensity parallel to the D.C. field, we report this threshold as (0.27 ± 0.10) × 10−4 Trms.
Search for cyclotron resonance in cells in vitro
Authors: Parkinson W. C. , Hanks C. T.
Published: February 2006

There are a number of reports of the plasma membrane transport of Ca2+ in biological systems being enhanced by low frequency electromagnetic fields (EMF), including reports that the enhancement involves a resonance‐type response at the cyclotron frequency for Ca2+ ions for geomagnetic values of the magnetic field. Using the fluorescent probe fura2, we find no evidence for changes in cytosolic calcium concentration in BALB/c3T3, L929, V‐79, and ROS, a rat osteosarcoma cell line, at the application of both resonant and nonresonant EMF.
Ambient 60‐Hz magnetic flux density in an urban neighborhood
Authors: Dlugosz Lawrence J. , Byers Tim , Vena John , Zielezny Maria
Published: February 2006

A residential neighborhood in Buffalo, NY, was surveyed with a magnetic field meter to evaluate whether or not spot measurements are reliable predictors of the 60‐Hz fields at street corners and residences. The results of repeated measurements over 7 days at 33 street corners in this neighborhood indicate that day‐to‐day variation in power line magnetic fields is negligible (intraclass correlation coefficient = 0.94). Multivariate linear regression analysis of the data indicates that transmission lines and thick, three‐phase primary wires near the field measurement site are strong predictors and account for the majority of the ambient magnetic field variance between locations (multiple correlation coefficient squared = 0.60; F ratio = 22.2, P < .001). Magnetic fields measured at the front sidewalk were highly correlated with fields at the front doorsteps of 45 homes in this neighborhood (γ = 0.81). These results suggest that ambient power line magnetic field levels at urban residences can be reliably characterized on a one‐time site inspection using a hand‐held magnetic field meter and a simple wiring classification system.
Radiofrequency radiation‐induced calcium ion efflux enhancement from human and other neuroblastoma cells in culture
Authors: Dutta S. K. , Ghosh B. , Blackman C. F.
Published: February 2006

To test the generality of radiofrequency radiation‐induced changes in 45Ca2+ efflux from avian and feline brain tissues, human neuroblastoma cells were exposed to electromagnetic radiation at 147 MHz, amplitude‐modulated (AM) at 16 Hz, at specific absorption rates (SAR) of 0.1, 0.05, 0.01, 0.005, 0.001, and 0.0005 W/kg. Significant 45Ca2+ efflux was obtained at SAR values of 0.05 and 0.005 W/kg. Enhanced efflux at 0.05 W/kg peaked at the 13–16 Hz and at the 57.5–60 Hz modulation ranges. A Chinese hamster‐mouse hybrid neuroblastoma was also shown to exhibit enhanced radiation‐induced 45Ca2+ efflux at an SAR of 0.05 W/kg, using 147 MHz, AM at 16 Hz. These results confirm that amplitude‐modulated radiofrequency radiation can induce responses in cells of nervous tissue origin from widely different animal species, including humans. The results are also consistent with the reports of similar findings in avian and feline brain tissues and indicate the general nature of the phenomenon.
Low‐level microwave irradiation and central cholinergic activity: A dose‐response study
Authors: Lai H. , Carino M. A. , Horita A. , Guy A. W.
Published: February 2006

Rats were irradiated with circularly polarized, 2,450‐MHz pulsed microwaves (2‐μs pulses, 500 pulses per second [pps]) for 45 min in the cylindrical waveguide system of Guy et al:(Radio Sci 14:63–74, 1979). Immediately after exposure, sodium‐dependent high‐affinity choline uptake, an indicator of cholinergic activity in neural tissue, was measured in the striatum, frontal cortex, hippocampus, and hypothalamus. The power density was set to give average whole‐body specific absorption rates (SAR) of 0.3, 0.45, 0.6, 0.75, 0.9, or 1.2 W/kg to study the dose‐response relationship between the rate of microwave energy absorption and cholinergic activity in the different areas of the brain. Decrease in choline uptake was observed in the striatum at a SAR of 0.75 W/kg and above, whereas for the frontal cortex and hippocampus, decreases in choline uptake were observed at a SAR of 0.45 W/kg and above. No significant effect was observed in the hypothalamus at the irradiation power densities studied. The probit analysis was used to determine the SAR50 in each brain area, i.e., the SAR at which 50% of maximum response was elicited. SAR50 values for the striatum, frontal cortex, and hippocampus were 0.65, 0.38, and 0.44 W/kg, respectively.
Simple nonperturbing temperature probe for microwave/radio frequency dosimetry
Authors: Olsen R. G. , Bowman R. R.
Published: February 2006

We present a simple readout device that fills the void produced by the gradual disappearance of the Vitek model 101 Electrothermia Monitor. The new device uses commercially available probes that are similar to Bowman's (IEEE Trans Microwave Theory Tech MTT‐24:43–45, 1976) original design. As described, the device covers the range of 7 ° to 45 °C with an accuracy and resolution of better than 0.1 °C throughout. The digital readout (3½ digits) is proportional to the thermistor resistance in the tip of the probe; it is converted to temperature through a formula or printed table. Outdoor dosimetric comparisons between the new and Vitek devices were conducted. Results showed no significant difference in the calculated specific absorption rates (SARs); moreover, variance was lower in the data collected from the new device.
Magnetite and magnetotaxis in microorganisms
Authors: Frankel Richard B. , Blakemore Richard P.
Published: February 2006

Magnetotactic bacteria from freshwater and marine sediments orient and navigate along geomagnetic field lines. Their magnetotactic response is based on intracellular, single magnetic domains of ferrimagnetic magnetite, which impart a permanent magnetic dipole moment to the cell.
Conditioning analysis of magnetoreception in honeybees
Authors: Walker Michael M. , Bitterman M. E.
Published: February 2006

A central problem in the study of magnetic sensitivity in animals has been the lack of behavioral techniques sufficiently powerful for the systematic psychophysical work required for an understanding of magnetosensory capacity and of the transduction mechanism. In recent experiments, free‐flying honeybees have been conditioned to discriminate the presence and absence of localized magnetic dipole anomalies superimposed on the uniform background field of the earth. The results obtained thus far suggest that movement is necessary for conditioned responding to magnetic field stimuli and support the hypothesis that magnetic field transduction is based on single‐domain particles of magnetite found in the anterodorsal abdomen of honeybees.
Mechanical and electrical effects of high‐frequency and high‐intensity stimulation of muscle
Authors: Koniarek Jan P.
Published: February 2006

A unique tension response can be obtained by stimulating an isometrically held skeletal muscle or a single muscle fiber by a train of high‐frequency pulses (2,000 pps) at higher‐than‐normal intensity, or by a long DC pulse. It is called the tetanoid response, and it is composed of three well‐defined stages. Initially, tension develops rapidly, and mechanical output (P0) reaches about 0.35. Subsequently, this tension is maintained at a nearly steady level for the remainder of stimulation. After stimulation, a final increase of tension takes place.

Intracellular electrical recordings show that the initial development of tension is elicited by two or three action potentials generated at the beginning of the stimulation, and that no additional action potentials are generated for the remainder of stimulation. During stimulation, part of the fiber membrane (regarded in cross‐section) is depolarized, which generates tension, and part of the membrane is hyperpolarized. With termination of stimulation, a single action potential is elicited via anode‐break excitation (ABE) on the hyperpolarized portion of the membrane, which gives rise to the final increase of tension.
EMP simulators and public safety: An analysis
Authors: Agouridis D. C. , Easterly C. E.
Published: February 2006

Effects produced by electromagnetic fields from exoatmospheric nuclear detonations, known as electromagnetic pulses (EMPs) and devices, which simulate these EMPs are analyzed for their potential danger to human beings in contact with large energy collectors. Comparison is made with ANSI guidelines established for radio‐frequency electromagnetic fields.
In vitro fertilization of mouse ova by spermatozoa exposed isothermally to radio‐frequency radiation
Authors: Cleary S. F. , Liu L. M. , Graham R. , East J.
Published: February 2006

Mouse spermatozoa were exposed in vitro for 1 h to 27‐ or 2,450‐MHz CW RF radiation at SARs of 0 to 90 W/kg under isothermal (37 ± 0.2 °C) conditions. Exposure at either frequency to RF radiation at SARs of 50 W/kg or greater resulted in a statistically significant reduction in the ability of irradiated sperm to fertilize mouse ova in vitro (P < .05). Over the range of SARs there was no apparent difference in the effects of 27‐ vs. 2,450‐MHz RF radiation. There were no readily detectable exposure effects on spermatozoan morphology, ultrastructure, or capacitation. The reduction of in vitro fertilization is attributed to a direct effect of RF radiation on spermatozoa rather than to heating.
Influence of a stationary magnetic field on bioelectric properties of snail neurons
Authors: Balaban P. M. , Bravarenko N. I. , Kuznetzov A. N.
Published: February 2006

Identified cells of Helix lucorum L. received 20 min exposures to 23, 120, or 200 mT stationary magnetic field (MFs). Resting potentials and input resistances were measured. Controls were instituted for temperature changes and for mechanical and other sources of artifact. Resting potentials did not change with MF exposure. Input resistances decreased significantly in normally silent cells during MF exposure, but increased significantly in spontaneously active cells. The magnitudes of changes were monotonically related to strength of the MF. Changes in excitatory postsynaptic potentials were observed during MF exposure. Elimination of perineuronal glia by proteolytic enzymes eliminated the MF effects.
Combined DC and ELF magnetic fields can alter cell proliferation
Authors: Ross Stephen M.
Published: February 2006

Effects of extremely‐low‐frequency (ELF) electromagnetic fields on proliferation of rabbit‐ligament fibroblasts were examined. Markedly different effects, ranging from inhibition to stimulation of proliferation, were obtained, depending on the signal parameters of amplitude, frequency, and DC magnetic field. These results demonstrate that simple, single‐frequency signals can have dramatic effects on ligament cells, which may be useful for bioelectrical stimulation of growth and repair. Also, the range of frequencies examined in this study covered those commonly used in transmission of electrical energy (50 or 60 Hz), which indicates that further study of possible effects of exposure to fields generated by power transmission equipment is warranted.
Influence of 60‐Hz magnetic fields on sea urchin development
Authors: Zimmerman Selma , Zimmerman Arthur M. , Winters Wendell D. , Cameron Ivan L.
Published: February 2006

Continuous exposure of sea urchin (Strongylocentrotus purpuratus) embryos at 18°C to a cyclic 60‐Hz magnetic field at 0.1 mT rms beginning 4 min after insemination caused a significant developmental delay during the subsequent 23 hours. No delay in development was recorded for periods up to 18 hours after fertilization. At 18 h, most embryos were in the mesenchyme blastula stage. At 23 h, most control embryos were in mid‐gastrula whereas most magnetic‐field‐exposed embryos were in the early gastrula stage. Thus an estimated 1‐h delay occurred between these developmental stages. The results are discussed in terms of possible magnetic‐field modification of transcription as well as interference with cell migration during gastrulation. The present study extends and supports the growing body of information about potential effects of exposures to extremely‐low‐frequency (ELF) magnetic fields on developing organisms.
A three‐dimensional method for calculating currents induced in bodies by extremely low‐frequency electric fields
Authors: Takuma T. , Kawamoto T. , Isaka K. , Yokoi Y.
Published: February 2006

A user‐friendly, numerical program has been developed to permit the calculation of induced currents in modeled bodies of human and infrahuman subjects. The program is based on a charge‐simulation method (CSM), and it takes into account the three‐dimensional (3‐D) character of the extremely‐low‐frequency (ELF) electric field and of the models to be exposed. The principle of the method is to simulate a 3‐D object, for example, an animal model, by a combination of several parts (blocks) having simple geometric forms such as a sphere, a cylinder, or a cone. This approach permits easy preparation of input data on the dimensions of the blocks and their positions in a 3‐D arrangement. Other input data, such as the coordinates of the contour points and the imaginary values of charges inside objects, which are necessary in the calculations by CSM, are produced automatically by selecting an appropriate “level” for each block, according to its importance. To simulate parts having irregular shapes, special blocks may be added. In one series of experiments, induced currents were calculated for a baboon model in various postures: standing upright, positioned on four legs, and sitting on the floor. Calculated currents. the total induced current in particular, agreed very well with experimental values. Local currents in parts of the baboon models were more variable, ranging from 5% to 17% of measured values in the case of induced currents in the head. Some problems with this method, such as the effect of the dimensions of blocks or the choice of block levels, are discussed.
Extremely low‐frequency electric and magnetic fields and risk of human cancer
Authors: Coleman Michel P.
Published: February 2006

The reported association between the risk of human cancer and exposure to 50‐ or 60‐Hz electric and magnetic fields is difficult to evaluate from studies published to date. The association is now being reexamined in several large epidemiologic studies. In most of the studies, exposure will be assessed with newly designed, portable meters that allow direct and precise measurements of exposure to be performed easily for large numbers of individuals. The main features of the studies are summarized. At a meeting of principal investigators held in 1988 at the International Agency for Research on Cancer, broad guidelines were agreed for the design of this new generation of studies. These guidelines should improve the comparability of results and eventually provide a clearer assessment of human‐cancer risk from exposure to extremely low‐frequency electric and magnetic fields.
Altered operant behavior of adult rats after perinatal exposure to a 60‐Hz electromagnetic field
Authors: Salzinger Kurt , Freimark Steven , McCullough Malcolm , Phillips Donald , Birenbaum Leo
Published: February 2006

Rats were sham exposed or exposed perinatally to a 60‐Hz electromagnetic field, 22 days in utero and the first 8 days post partum. Each of the 30 once‐daily exposures was 20 h in duration. The electric component of the field was vertical 30 kV/m rms, and the magnetic field component was 100 μTG rms. Later, as adults, male rats were trained to emit an operant response when reinforced with food on a multiple, random‐interval schedule. Exposed rats (N = 21) gradually came to respond at significantly lower rates than did sham‐exposed controls (N = 20). This finding was confirmed and extended in a second, independently performed experiment. After a sequence including operant conditioning followed by experimental extinction of responding and then by a suspension of conditioning and finally by more than a month of reconditioning, slower rates of responding were found to persist in the adult animals. The evidence of altered behavior several months after combined, fetal‐neonatal exposure to an electromagnetic field presents an interesting contrast with other findings: Field‐exposed rats did not differ from sham‐exposed rats in terms of body mass, physical appearance, grossly observed activity level, or incidence of disease.
Dominant lethal studies in male mice after exposure to a 50‐Hz electric field
Authors: Kowalczuk C. I. , Saunders R. D.
Published: February 2006

Male C3H/He mice were sham‐exposed or exposed continuously for 2 weeks to a vertical, 50‐Hz, electric field at 20 kV/m rms. Densities of currents induced in the testes are estimated to be near 100 μA/m2. After the exposure, each male was mated with two different female mice each week during a period of 8 weeks. By this schedule, female mice were impregnated with sperm that had been exposed to the electric field at different stages of the spermatogenic cycle. No significant differences as a function of exposure condition were observed in pregnancy rates or in survival of embryos before or after implantation. The absence of effects was not due to insensitivity of assays; other mice that were exposed to X‐rays (dose to testes = 1.5 Gy) presented reliable evidence of mutagenesis.
Development of chicken embryos in a pulsed magnetic field
Authors: Berman E. , Chacon L. , House D. , Koch B. A. , Koch W. E. , Leal J. , Løvtrup S. , Mantiply E. , Martin A. H. , Martucci G. I. , Mild K. H. , Monahan J. C. , Sandström M. , Shamsaifar K. , Tell R. , Trillo M. A. , Ubeda A. , Wagner P.
Published: February 2006

Six independent experiments of common design were performed in laboratories in Canada, Spain, Sweden, and the United States of America. Fertilized eggs of domestic chickens were incubated as controls or in a pulsed magnetic field (PMF); embryos were then examined for developmental anomalies. Identical equipment in each laboratory consisted of two incubators, each containing a Helmholtz coil and electronic devices to develop, control, and monitor the pulsed field and to monitor temperature, relative humidity, and vibrations. A unipolar, pulsed, magnetic field (500‐μs pulse duration, 100 pulses per s, 1‐μT peak density, and 2‐μs rise and fall time) was applied to experimental eggs during 48 h of incubation. In each laboratory, ten eggs were simultaneously sham exposed in a control incubator (pulse generator not activated) while the PMF was applied to ten eggs in the other incubator. The procedure was repeated ten times in each laboratory, and incubators were alternately used as a control device or as an active source of the PMF. After a 48‐h exposure, the eggs were evaluated for fertility. All embryos were then assayed in the blind for development, morphology, and stage of maturity. In five of six laboratories, more exposed embryos exhibited structural anomalies than did controls, although putatively significant differences were observed in only two laboratories (two‐tailed Ps of .03 and <.001), and the significance of the difference in a third laboratory was only marginal (two‐tailed P = .08). When the data from all six laboratories are pooled, the difference in incidence of abnormalities in PMF‐exposed embryos (∼25 percent) and that of controls ( ∼ 19 percent) although small, is highly significant, as is the interaction between incidence of abnormalities and laboratory site (both Ps < .001). The factor or factors responsible for the marked variability of inter‐laboratory differences are unknown.
Exposure of mammalian cells to 60‐Hz magnetic or electric fields: Analysis of DNA repair of induced, single‐strand breaks
Authors: Frazier M. E. , Reese J. A. , Morris J. E. , Jostes R. F. , Miller D. L.
Published: February 2006

DNA damage was induced in isolated human peripheral lymphocytes by exposure at 5 Gy to 60Co radiation. Cells were permitted to repair the DNA damage while exposed to 60‐Hz fields or while sham‐exposed. Exposed cells were subjected to magnetic (B) or electric (E) fields, alone or in combination, throughout their allotted repair time. Repair was stopped at specific times, and the cells were immediately lysed and then analyzed for the presence of DNA single‐strand breaks (SSB) by the alkaline‐elution technique. Fifty to 75 percent of the induced SSB were repaired 20 min after exposure, and most of the remaining damage was repaired after 180 min. Cells were exposed to a 60‐Hz ac B field of 1 mT; an E field of 1 or 20 V/m; or combined E and B fields of 0.2 V/m and 0.05 mT, 6 V/m and 0.6 mT, or 20 V/m and 1 mT. None of the exposures was observed to affect significantly the repair of DNA SSB.
Changes in levels of c‐myc and histone H2B following exposure of cells to low‐frequency sinusoidal electromagnetic fields: Evidence for a window effect
Authors: Wei Lin‐Xiang , Goodman Reba , Henderson Ann
Published: February 2006

Human HL‐60 cells were exposed for 20 min to an electromagnetic field at frequencies ranging from 15 to 150 Hz and at densities from 0.2 to 2.3 mT (2 to 23 gauss). Following each exposure, quantitative levels of c‐myc and histone H2B transcripts were determined by dot‐blot hybridization analyses and compared with unexposed control samples. The most pronounced increase in each transcript occurred after exposure at 45 Hz, with levels more than four times that found in unexposed controls.
A simple model for calculating residential 60‐Hz magnetic fields
Authors: Mader D. L. , Barrow D. A. , Donnelly K. E. , Scheer R. R. , Sherar M. D.
Published: February 2006

A model is presented that permits the calculation of densities of 60‐Hz magnetic fields throughout a residence from only a few measurements. We assume that residential magnetic fields are produced by sources external to the house and by the residential grounding circuit. The field from external sources is measured with a single probe. The field produced by the grounding circuit is calculated from the current flowing in the circuit and its geometry. The two fields are combined to give a prediction of the total field at any point in the house. A data‐acquisition system was built to record the magnitude and phase of the grounding current and the field from external sources. The model's predictions were compared with measurements of the total magnetic field at a single location in 23 houses; a correlation coefficient of .87 was obtained, indicating that the model has good predictive capability. A more detailed study that was carried out in one house permitted comparisons of measurements with the model's predictions at locations throughout the house. Again, quite reasonable agreement was found. We also investigated the temporal variability of field readings in this house. Daily magnetic field averages were found to be considerably more stable than hourly averages. Finally, we demonstrate the use of the model in creating a profile of the magnetic fields in a home.
Amplitude windows and transiently augmented transcription from exposure to electromagnetic fields
Authors: Litovitz T. A. , Montrose C. J. , Goodman Reba , Elson Edward C.
Published: February 2006

The exposure of cells to relatively low‐intensity, pulsed, low‐frequency electromagnetic fields can result in a transient augmentation of mRNA synthesis. Under certain conditions of irradiation, the augmentation is a function of the strength of the electromagnetic field. A linear, multi‐step, chemical‐reaction model accounts for many of the principal features that are observed in both the time‐ and intensity‐dependent variations of transcriptional effects. The crucial assumption in the model is that the direct effect of electromagnetic fields on exposed cells is an increase in the rate constant that characterizes one of the intermediate sequential reactions in the synthesis of mRNA.
Lay understanding of low‐frequency electric and magnetic fields
Authors: Morgan M. Granger , Florig H. Keith , Nair Indira , Cortés Concepcion , Marsh Kevin , Pavlosky Karen
Published: February 2006

People do not start with a blank slate when they hear risk‐communication messages. All such messages are processed through existing knowledge structures and understanding. Hence, to design effective and reliable risk‐communication materials one must understand the state of people's knowledge—correct and incorrect—about an issue. We developed a simple “mental model” of what people minimally need to know to make informed decisions about field‐related issues. Then we performed studies to explore how and to what extent respondents of various groups understood physical properties of 60‐Hz electric and magnetic fields. Actual knowledge of respondents was then compared with the predicates of the model. Electrical engineering juniors and semi‐technical employees of utilities displayed a good command of most of the concepts in the simple model, but little awareness of the limits to their knowledge. Lay respondents correctly knew only a few of the simplest elements of the model, but they displayed a much greater awareness of the limits to their knowledge. Both lay and semi‐technical respondents were found to share several misconceptions. On average, they correctly rank‐ordered some common field‐exposure conditions by field strength, but they could not differentiate between electric and magnetic fields and could not differentiate among field strengths associated with different appliances. Most respondents dramatically underestimated the range of actual field strengths. Many respondents understood that field strength decreases with distance from a source, but they underestimated the rate of decrease. In contrast to X‐rays and microwaves, which respondents appeared to think about in rather similar terms, 60‐Hz fields were not thought of as being highly similar to any other agent, although the closest parallels were found with ultrasound. Changes in mood, thought, and behavior, and the existence of an “electrical aura,” were all seen as plausible results of exposure to a 60‐Hz field. Although lay respondents displayed a variety of incomplete and confusing ideas, most of these ideas probably do not pose significant obstacles to the learning of a correct, simple, mental model.
Dielectric properties of mouse MCA1 fibrosarcoma at different stages of development
Authors: Swarup A. , Stuchly S. S. , Surowiec A.
Published: February 2006

The in vitro bulk electrical properties of MCA1 fibrosarcoma induced in C57BI/6 male mice were measured at frequencies of 10 kHz to 100 MHz, with some tissues measured to 2 GHz. The properties of normal surrounding tissue also were measured. A comparison of the dielectric properties between three different stages of tumor development as well as that between various locations within the tumor is reported.

Statistical analysis of the experimental results revealed statistically significant differences in the dielectric constant and conductivity of the tumor tissues at various stages of development as measured at frequencies below 10 MHz. Conductivity values at different stages also differ at a frequency of 100 MHz. At other frequencies these differences were found to be statistically insignificant.
Naltrexone pretreatment blocks microwave‐induced changes in central cholinergic receptors
Authors: Lai H. , Carino M. A. , Wen Y. F. , Horita A. , Guy A. W.
Published: February 2006

Repeated exposure of rats to pulsed, circularly polarized microwaves (2,450‐MHz, 2‐μs pulses at 500 pps, power density 1 mW/cm2, at an averaged, whole‐body SAR of 0.6 W/kg) induced biphasic changes in the concentration of muscarinic cholinergic receptors in the central nervous system. An increase in receptor concentration occurred in the hippocampus of rats subjected to ten 45‐min sessions of microwave exposure, whereas a decrease in concentration was observed in the frontal cortex and hippocampus of rats exposed to ten 20‐min sessions. These findings, which confirm earlier work in the authors' laboratory, were extended to include pretreatment of rats with the narcotic antagonist naltrexone (1 mg/kg, IP) before each session of exposure. The drug treatment blocked the microwave‐induced changes in cholinergic receptors in the brain. These data further support the authors' hypothesis that endogenous opioids play a role in the effects of microwaves on central cholinergic systems.
The solar wind and hallucinations—A possible relation due to magnetic disturbances
Authors: Randall Walter , Randall Steffani
Published: February 2006

Data from the 19th century on hallucinations and magnetic disturbances were found to exhibit a direct and statistically significant correlation. The aa magnetic index over the period 1868–89 and concurrent visual hallucinatory activity were found to co‐vary (Spearman coefficient = .64; P < .05). Magnetic influences on the pineal hormone, melatonin, are suggested as a possible source of variation.
Effect of localized pulsed electromagnetic fields on tail‐suspension osteopenia in growing mice
Authors: Simske S. J. , Wachtel H. , Luttges M. W.
Published: February 2006

Pulsed magnetic fields (PEMFs) have been used effectively to treat bone fractures and sciatic‐nerve‐section‐induced osteopenias. Properly applied PEMFs are presumed to stimulate osteogenesis. Mouse‐tail suspension has been implemented as a means of inducing an osteopenic response in the long bones of the hind limbs. To evaluate localized PEMF effects, the mouse‐suspension model was modified to accommodate the use of miniature wire coils affixed directly to the rear legs. Laterally and axially orientated PEMF effects were compared. Three test groups of mice included (C) control mice, (S) tail‐suspended mice with treatment apparatus attached, and (SF) tail‐suspended mice with apparatus attached and PEMFs delivered. The SF group was divided into mice receiving axial or lateral PEMFs. Significant bone changes occurred in suspended as compared with control mice after a 2‐week test period. The PEMF mice showed significantly fewer osteopenic effects than did untreated, suspended mice. These findings are based on biomechanical measures of stiffness, strength, ductility, and energy as well as whole‐bone mass and porosity. The effects of PEMFs on these properties differ for axial and lateral exposures. The results are discussed in terms of mechanisms underlying PEMF effects.
Miniature‐probe measurements of electric fields and currents induced by a 60‐Hz magnetic field in rat and human models
Authors: Miller Douglas L.
Published: February 2006

A miniaturized probe was designed and built to provide detailed data on fields induced by a uniform 60‐Hz magnetic field in homogeneous models of rat and human. The probe employed three silver wires twisted and potted in an 8‐cm hypodermic needle. The exposed tips of the wires formed three sensing electrodes with a centered ground; highly sensitive voltage measurements were enabled by a lock‐in amplifier. Tests were conducted in a 1‐mT rms field that was uniform within ± 5%. The models were made by casting 1.5% agar at 1‐S/m conductivity into plastic‐foam molds. The rat model was scaled 1:1 as an adult (22 cm length; mass about 640 g). The human model was scaled 1:4 as an adult (height = 46.5 cm; mass 1.4 kg). The probe was inserted into each model in several regions, and readings of induced fields were made under different exposure geometries. Maximal strengths of fields induced near the surface of the torso were as high as 120 μV/cm in the laterally exposed rat model. Data extrapolated from the quarter‐scale human model revealed that an induced field as high as 700 μV/cm could occur at the torso of a frontally exposed human adult. An overall size‐scale factor of about 5 appears to be appropriate for experimental exposures of rats that are intended to simulate currents induced in human beings by magnetic fields. The average strength of electric fields induced in the torso by a 1‐mT magnetic field is comparable to that by a vertical electric‐field at 60 kV/m and 28 kV/m, respectively, for the rat and human.
An increase in the negative surface charge of U937 cells exposed to a pulsed magnetic field
Authors: Smith Orla M. , Goodman Eugene M. , Greenebaum Ben , Tipnis Pratima
Published: February 2006

Pulsed magnetic fields have been used to enhance healing of bone fractures and purportedly of lesions in soft tissue. However, their mechanism of action is poorly understood. We report changes in the plasma membrane of a nonadherent mammalian cell line, U937, which was exposed to a 25‐pps magnetic field for 48 hours. Aqueous polymer two‐phase partition studies showed that magnetic‐field‐exposed cells exhibited an increased negative surface charge but membrane hydrophobicity was not significantly altered. The observed increase in membrane electronegativity of exposed cells did not reflect a significant change in growth rate.
Thermal and metabolic responsiveness of Japanese quail embryos following periodic exposure to 2,450 MHz microwaves
Authors: Spiers Donald E. , Baummer Sheila C.
Published: February 2006

Two studies were performed to determine if repeated exposure of the avian egg to microwaves can alter metabolism, temperature, and growth rate of embryos. Another aim was to supplement conventional heating with microwave heating and provide an optimal temperature for growth. Japanese quail (Coturnix coturnix japonica) eggs were exposed from day 1 through 15 of incubation (8 h/day) to sham or microwave (2,450 MHz) irradiation. Microwave exposures were at two power densities, 5 or 20 mW/cm2, and at three ambient temperatures (Tas), 30.0, 33.1, or 35.4 °C. Specific absorption rates for unincubated and 15‐day‐old incubated eggs were, respectively, 0.76 and 0.66 W kg−1 mW−1 cm−2 (i.e., 3.8 and 3.3 W/kg at 5 mW/cm2 and 15.2 and 13.2 W/kg at 20 mW/cm2). Eggs were concurrently sham exposed at each of five Tas, ranging from 27.9 to 37.5 °C. Tests were conducted during the 16th day of incubation (i.e., I day post‐treatment), in the absence of microwaves, to determine metabolic rate of embryos and internal and external egg temperatures at different Tas. Repeated exposures to microwaves at 5 and 20 mW/cm2 at the same Ta (30 °C) increased wet‐embryo mass on the 16th day by an average, respectively, of 9% and 61% when compared with predicted masses for embryos exposed at the same Ta in the absence of microwave radiation. There was no reliable indication, from post‐treatment tests and comparisons with control embryos of similar mass, that repeated exposure to microwave radiation resulted in abnormal physiological development. Microwave radiation can be used to increase egg temperature and embryonic growth rate at Tas below normal incubation level without altering basic metabolic and thermal characteristics of the developing bird.