bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exposure to time varying magnetic fields associated with magnetic resonance imaging reduces fentanyl‐induced analgesia in mice
Authors: Teskey G. Campbell , Ossenkopp Klaus‐Peter , Prato Frank S. , Kavaliers Martin 
Published: February 2006

AbstractThe effects of exposure to clinical magnetic resonance imaging (MRI) on analgesia induced by the mu opiate agonist, fentanyl, was examined in mice. During the dark period, adult male mice were exposed for 23.2 min to the time‐varying (0.6 T/sec) magnetic field (TVMF) component of the MRI procedure. Following this exposure, the analgesic potency of fentanyl citrate (0.1 mg/kg) was determined at 5, 10, 15, and 30 min post‐injection, using a thermal test stimulus (hot‐plate 50°C). Exposure to the magnetic‐field gradients attenuated the fentanyl‐induced analgesia in a manner comparable to that previously observed with morphine. These results indicate that the time‐varying magnetic fields associated with MRI have significant inhibitory effects on the analgesic effects of specific mu‐opiate‐directed ligands.
Influence of microwaves on the beating rate of isolated rat hearts
Authors: Yee Kuo‐Chiang , Chou Chung‐Kwang , Guy Arthur W. 
Published: February 2006

AbstractPrevious reports have shown that microwave exposure can decrease the beating rate of isolated rat hearts. These experiments were conducted at room temperature and with the hearts exposed to air. We observed arrhythmia frequently at room temperature, and the variation of heart beat was so large that it makes the results difficult to reproduce. Therefore, we employed a double‐circulating system to provide perfusion through the coronary artery and around the outside of the heart to maintain the rat hearts at 37.7°C. No arrhythmias were observed in our experiments, and the hearts were beating for at least 1 h. The effects of 16‐Hz modulated 2,450‐MHz pulsed microwaves (10 μs, 100 pps) on the beating rate of 50 isolated rat hearts were studied. Results showed no statistically significant changes of heart rate in exposed groups at SARs of 2 and 10 W/kg compared with the control group. The effect seen at 200 W/kg was shown to be similar to that resulting from heating the heart.
Chronic exposure to elf fields may induce depression
Authors: Wilson Bary W. 
Published: February 2006

AbstractExposure to extremely‐low‐frequency (ELF) electric or magnetic fields has been postulated as a potentially contributing factor in depression. Epidemiologic studies have yielded positive correlations between magnetic‐ and/or electric‐field strengths in local environments and the incidence of depression‐related suicide. Chronic exposure to ELF electric or magnetic fields can disrupt normal circadian rhythms in rat pineal serotonin‐N‐acetyltransferase activity as well as in serotonin and melatonin concentrations. Such disruptions in the circadian rhythmicity of pineal melatonin secretion have been associated with certain depressive disorders in human beings. In the rat, ELF fields may interfere with tonic aspects of neuronal input to the pineal gland, giving rise to what may be termed “functional pinealectomy.” If long‐term exposure to ELF fields causes pineal dysfunction in human beings as it does in the rat, such dysfunction may contribute to the onset of depression or may exacerbate existing depressive disorders.
Myelogenous leukemia and electric blanket use
Authors: Preston‐Martin Susan , Peters John M. , Yu Mimi C. , Garabrant David H. , Bowman Joseph D. 
Published: February 2006

AbstractIn a case‐control study of adult acute and chronic myelogenous leukemia in Los Angeles County, we tested the hypothesis that excess exposure to electromagnetic fields from electric blankets was associated with risk of leukemia. We did this by studying 116 cases of acute myelogenous leukemia (AML) and 108 cases of chronic myelogenous leukemia (CML) along with matched neighborhood controls. The cases and controls were queried as to electric blanket use and the risks computed. For AML the risk was 0.9 (95% CI 0.5–1.6) and for CML the risk was 0.8 (95% CI 0.4–1.6). Cases did not differ from controls by duration of use, year of first regular use, year since last use, or socioeconomic status. Our best estimates of exposure indicate that electric blanket use increases overall exposure to electric fields by less than 50% and magnetic fields by less than 100%. We conclude that there is no major leukemogenic risk associated with electric blanket use in Los Angeles County.
Influence of electromagnetic fields on the efflux of calcium ions from brain tissue in vitro: A three‐model analysis consistent with the frequency response up to 510 Hz
Authors: Blackman C. F. , Benane S. G. , Elliott D. J. , House D. E. , Pollock M. M. 
Published: February 2006

AbstractThe frequency dependence of electromagnetic field‐induced calcium‐ion efflux from chicken brain tissues has been examined at 15‐Hz intervals over the range 1–510 Hz. The electric field component was 15 Vrms/m and the magnetic component varied between 59 and 69 nTrms. No patterns of response as a function of frequency could be readily discerned when the differences in mean efflux values between exposed and sham samples were compared. However, the calculated P‐value, a function that combines at each frequency the difference between the means of the exposed and sham groups with the variance of each group, does provide a basis for hypothesizing the existence of three frequency‐dependent patterns in the data. One pattern includes all the highly significant (P < .01) responses which occur between 15 and 315 Hz, at 30‐Hz intervals; two independent trials at 165 Hz, giving nonsignificant responses (P > .5), break this pattern into two groups of five frequencies each, which is contrary to the expected result for a simple Lorentz‐force interaction. However, another pattern of significant results at 60, 90, and 180 Hz, but not at 300 Hz, is consistent with a Lorentz‐force model. A third pattern, composed of only one significant response at 405 Hz, is very close to the resonance predicted on a linear extrapolation from high‐frequency data for 13carbon atoms. This hypothetical ordering of the frequency‐response profile provides the basis for future experimental designs to test each possible interaction model and for their connection to the calcium‐ion efflux endpoint.
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

AbstractLevels 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

AbstractLarge 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

AbstractAn 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

AbstractSodium‐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

AbstractResults 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.
Lithium as a normal metabolite: Some implications for cyclotron resonance of ions in magnetic fields
Authors: Smith Robert F. 
Published: February 2006

AbstractCyclotron 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

AbstractA 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

AbstractThis 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

AbstractThe 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

AbstractMagnetic 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

AbstractExperiments 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

AbstractThere 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

AbstractA 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

AbstractTo 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

AbstractRats 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.