bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo studies of the effect of magnetic field exposure on ontogeny of choline acetyltransferase in the rat brain
Authors: Sakamoto Shuichi , Hagino Nobuyoshi , Winters Wendell D. 
Published: February 2006

AbstractDevelopmental increases of the activity of choline acetyltransferase (ChAT) were examined in the brains of fetuses and offspring from parent rats continuously exposed to a 500 mG, 60 Hz circularly polarized (CP) magnetic field (MF) prior to pregnancy, and further, during pregnancy and lactation. In developing rats between 12 days and 20 days of embryogenesis that were housed in a control unit, i.e., nonexposed to MF, the specific activity of ChAT in whole brain specimens increased from 2.4% to 6.9% of adult activity, while specific activity of ChAT in rat brain specimens between 12 days of embryogenesis and 10 days of postpartum increased from 2.4% to 21.6% of adult activity. On the other hand, the specific activity of ChAT in whole brain specimens from rats under housed MF exposure conditions was found to increase from 2.6% to 6.7% of adult activity between 12 days and 20 days of embryogenesis and from 2.6% to 21.6% of adult activity between 12 days of embryogenesis and 10 days postpartum. Furthermore, the effect of the same test magnetic environment on the specific activity of ChAT in the brains of parental rats was examined in order to determine whether magnetic field exposure of parental rats might reflect onto the development of fetal brain. It was observed that continuous exposure of parental rats to a 500 mG, 60 Hz CP MF did not show any significant changes in the specific activity of ChAT in the septodiagonal band complex, dorsal and ventral hippocampus, striatum, and frontoparietal cerebral cortex, as compared with the same brain regions of control subjects. As far as the development of cholinergic neural circuits was concerned, these test magnetic environments did not interfere in their development and it suggested that parental‐fetal intercommunication might provide relatively stable states for neural development, even under these test magnetic environments. © 1993 Wiley‐Liss. Inc.
Studies on the possible biological effects of 50 Hz electric and/or magnetic fields: Evaluation of some glycolytic enzymes, glycolytic flux, energy and oxido‐reductive potentials in human erythrocytes exposed in vitro to power frequency fields
Authors: Dachà M. , Accorsi A. , Pierotti C. , Vetrano F. , Mantovani R. , Guidi G. , Conti R. , Nicolini P. 
Published: February 2006

AbstractAn attempt has been made to understand whether 50 Hz electric and magnetic fields (EMFs) are involved in producing bioeffects by exposing human erythrocytes in vitro. The study evaluated some key glycolytic enzymes, glucose consumption, lactate production, energy charge, 2,3‐diphosphoglycerate, and reduced glutathione levels. all of which are biochemical parameters significant to erythrocyte function. Cells exposed to individual or superimposed EMFs have not shown any significant difference compared with the controls. © 1993 Wiley‐Liss. Inc.
The role of coherence time in the effect of microwaves on ornithine decarboxylase activity
Authors: Litovitz T. A. , Krause D. , Penafiel Miguel , Elson Edward C. , Mullins J. M. 
Published: February 2006

AbstractPreviously, we demonstrated the requirement for a minimum coherence time of an applied, small amplitude (10 μT) ELF magnetic field if the field were to produce an enhancement of ornithine decarboxylase activity in L929 fibroblasts. Further investigation has revealed a remarkably similar coherence time phenomenon for enhancement of ornithine decarboxylase activity by amplitude‐modulated 915 MHz microwaves of large amplitude (SAR 2.5 W/kg). Microwave fields modulated at 55, 60, or 65 Hz approximately doubled ornithine decarboxylase activity after 8 h. Switching modulation frequencies from 55 to 65 Hz at coherence times of 1.0 s or less abolished enhancement, while times of 10 s or longer provided full enhancement. Our results show that the microwave coherence effects are remarkably similar to those observed with ELF fields. © 1993 Wiley‐Liss. Inc.
Effects of time‐varying uniform magnetic fields on Natural Killer cell activity and antibody response in mice
Authors: de Seze R. , Bouthet C. , Tuffet S. , Deschaux P. , Caristan A. , Moreau J. M. , Veyret B. 
Published: February 2006

AbstractNatural Killer cell activity and antibody response were studied in Balb/c mice which were exposed in vivo to uniform pulsed magnetic fields (square‐wave, 0.8 Hz, 120 mT maximum field strength, 0.1 s rise‐time) for 5 days, 10 h/day. No effects were found in antibody response to sheep red blood cell (SRBC) immunization as assayed by counting the plaque‐forming cells (PFC) in the spleens of animals on the sixth day. Following 5‐day exposures, the activity of Natural Killer (NK) cells was measured in vitro by challenge with YAC‐1 cells, in experiments in which mice were not immunized. An increase of NK cytotoxic activity due to exposure was found which depended on the age of the mice (effect observed above 12 weeks) and on the strength of the applied field (effect observed above 30 mT). © 1993 Wiley‐Liss. Inc.
A scheme for incorporating DC magnetic fields into epidemiological studies of EMF exposure
Authors: Blackman Carl F. , Most Bernard 
Published: February 2006

AbstractExperimental data on calcium‐ion release in chicken brain tissue suggest that biological effects of electric and magnetic fields (EMFs) are concentrated near certain “active combinations” of DC magnetic field strength and “effective” AC magnetic field frequencies. We hypothesize that active AC/DC combinations may exist and suggest that epidemiologic data, coupled with DC magnetic field measurements, may be used to identify critical exposure conditions. An empirical model is used to calculate these multiple active combinations at any given DC magnetic field strength and to define a rating system that incorporates the proximity of AC magnetic field frequencies generated by electric power lines to the new, computed effective frequencies. Such an exposure score may be useful in investigating correlations of EMF exposure with disease incidence. For 60 Hz and 50 Hz, the highest EMF exposure scores occurred at DC field strengths of 506 mG and 422 mG, respectively. The exposure score contains a factor which may be adjusted to reflect the importance of harmonics of the AC magnetic field as well as of the fundamental frequency. Using this factor, we consider two important special cases consistent with chick brain data: 1) we consider active pairs associated with all detectable harmonics (up to 660 Hz) without regard to relative intensity of the harmonics, and 2) we use the relative intensities of the AC field frequencies to adjust their contribution to the exposure score. © 1993 Wiley‐Liss. Inc.
Calcium‐ion movement and contractility in atrial strips of frog heart are not affected by low‐frequency‐modulated, 1 GHz electromagnetic radiation
Authors: Schwartz Jean‐Louis , Mealing Geoffrey A. R. 
Published: February 2006

AbstractCalcium efflux from electrically stimulated, 45Ca2+‐preloaded atrial strips of the frog heart was measured from samples of the rinsing perfusate collected at 2‐min intervals for 32 min in a continuous perfusion chamber. Contractile force was simultaneously monitored. The specimen chamber was located in a stripline apparatus in which the atrial strips were exposed for 32 min to constant (CW) or amplitude‐modulated (AM), 1 GHz electromagnetic (EM) fields at specific absorption rates (SAR) ranging from 3.2 μW/kg to 1.6 W/kg. Amplitude modulation was either at 0.5 Hz, in synchrony with the electrical stimulus applied to the preparation, or at 16 Hz. Neither unmodulated nor 0.5 Hz or 16 Hz modulated 1 GHz waves affected the movement of calcium ions or the contractile force in isolated atrial strips of the frog heart. © 1993 Wiley‐Liss, Inc.
Facility for chronic exposure of rats to ELF magnetic fields
Authors: Yasui Mitsuru , Otaka Yoshihisa 
Published: February 2006

AbstractThe facility consists of a 12 × 11.5 × 2.4 m high room containing six sets of exposure apparatus and the other equipment necessary to maintain a pathogen‐free system. The apparatus sets produced 5 mT (rms), 0.5 mT, or a sham exposure. The apparatus was arranged in the room to minimize the fringing field of the 5 mT set at the sham position. Each set was 3.85 × 1.80 × 0.66 m in outside dimension, containing 24 cages in the magnetically homogeneous region. The apparatus was designed using Harvey's figure‐eight‐configuration and generated a horizontal sinusoidal alternating field. In order to save electric power, the coil of the apparatus constituted a 50 Hz LC resonance circuit with a condensor bank to which electric power was supplied to compensate losses. Magnetic flux density was kept constant by controlling the coil current. Although mild steel was used in the skeleton of the building, the fringing flux at the sham was as low as 0.1 to 1 μT. Stainless steel was used for ventilating ducts, racks for the cages, cage covers, feeder baskets, and watering nozzles. The homogeneity of the field was measured to be ± 10% in the animal residence area, and food and water consumption was found to be unaffected by the field. At 5 mT, the coil current was 370 A, and the hollow coil was cooled by a stream of 20°C water to prevent both heat and dew on the coil surface. Vibration and acoustic noise was prevented by fiber reinforced plastic framework of the coil. High harmonic distortion was not observed at the output terminal of the coil driver. The facility has operated without trouble for 2 years. © 1993 Wiley‐Liss, Inc.
Exposure to 60 Hz magnetic fields in the electric utility work environment
Authors: Sahl Jack D. , Kelsh Michael A. , Smith Robert W. , Aseltine Deborah A. 
Published: February 2006

AbstractResearch that has attempted to examine the relationship between work exposures to magnetic fields and health effects has suffered from limited exposure information. Power‐frequency electric and magnetic (EM) field exposures vary substantially between industries, occupations, and individuals. In this study magnetic field data were collected for a variety of occupational categories within an electric utility. The sampling procedures emphasized craft occupations that were presumed to have higher exposures to magnetic fields. The objectives were to provide better exposure information for an ongoing cancer mortality study, examine the relationship between different summary measures of magnetic field exposure, and make available descriptive information useful for exposure reduction and worker education. Principal components analysis (PCA) and Varimax rotation were used to explore the relationships between the different summary measures among all utility workers and among the subset of electrical craft occupations. Discriminant analysis was used to assess summary measures of exposure that differentiated occupational groups. Measurements for 770 days generated a total of 42378 hours of magnetic field data. Eleven summary indices of exposure were calculated for specific occupational groups. These include arithmetic mean, geometric mean, median, 95th and 99th percentiles, and fraction of measurements exceeding .5, 1, 5, 10, and 100 μT. Electrical craft occupations had higher work exposures than non‐craft occupations. Electricians and substation operators had the highest exposures among craft occupations.We identified subsets of summary measures that were intercorrelated. The first PCA axis included the geometric mean, median, and the fractions exceeding 0.5 and 1.0 μT. This set of measures also were best at discriminating occupational groups. The relevance of these findings may become more important if consistent associations are found between particular occupations and disease and particular occupations and magnetic field summary measures. Further research is needed to evaluate these exposure assessment findings. © 1994 Wiley‐Liss, Inc.
Development of a protocol for assessing time‐weighted‐average exposures of young children to power‐frequency magnetic fields
Authors: Kaune W. T. , Darby S. D. , Gardner S. N. , Hrubec Z. , Iriye R. N. , Linet M. S. 
Published: February 2006

AbstractA study was carried out in 1990 to guide the development of a protocol for assessing residential exposures of children to time‐weighted‐average (TWA) power‐frequency magnetic fields. The principal goal of this dosimetry study was to determine whether area (i.e., spot and/or 24 h) measurements of power‐frequency magnetic fields in the residences and in the schools and daycare centers of 29 children (4 months through 8 years of age) could be used to predict their measured personal 24‐h exposures. TWA personal exposures, measured with AMEX‐3D meters worn by subjects, were approximately log‐normally distributed with both residential and nonresidential geometric means of 0.10 μT (1.0 mG). Between‐subjects variability in residential personal exposure levels (geometric standard deviation of 2.4) was substantially greater than that observed for nonresidential personal exposure levels (1.4). The correlation between log‐transformed residential and total personal exposure levels was 0.97. Time‐weighted averages of the magnetic fields measured in children's bedrooms, family rooms, living rooms, and kitchens were highly correlated with residential personal exposure levels (r = 0.90). In general, magnetic field levels measured in schools and daycare centers attended by subjects were smaller and less variable than measured residential fields and were only weakly correlated with measured nonresidential personal exposures. The final measurement protocol, which will be used in a large US study examining the relationship between childhood leukemia and exposure to magnetic fields, contains the following elements: normal‐ and low‐power spot magnetic field measurements in bedrooms occupied by subjects during the 5 years prior to the date of diagnosis for cases or the corresponding date for controls; spot measurements under normal and low power‐usage conditions at the centers of the kitchen and the family room; 24‐h magnetic‐field recordings near subjects' beds; and wire coding using the Wertheimer‐Leeper method. © 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.
Magnetic fields after translation in Escherichia coli
Authors: Goodman Eugene M. , Greenebaum Ben , Marron Michael T. 
Published: February 2006

AbstractQuantitative two‐dimensional gel electrophoresis of proteins in E. coli exposed for 60 min to weak, pulsed magnetic fields (1.5 mT peak) show that numerous proteins are both increased and decreased by a factor of 2 or more. An increase in the levels of two proteins, the a subunit of DNA‐dependent RNA polymerase and NusA, was confirmed by Western blot analysis. © 1994 Wiley‐Liss, Inc.
Enhanced mutagenic effect of a 60 Hz time‐varying magnetic field on numbers of azide‐induced TA100 revertant colonies
Authors: Tabrah Frank L. , Mower Howard F. , Batkin Stanley , Greenwood Peter Bryant 
Published: February 2006

AbstractForty‐eight hours exposure to a two Gauss (0.2 mT) rms 60 Hz time varying sinusoidal electromagnetic field increased the number of azide induced TA100 revertant colonies of Salmonella typhimurium 14% as compared with controls in the ambient < 2 milli‐Gauss 60 Hz field. In the absence of the electromagnetic field, the numbers of mutant colonies grown within and outside the non‐energized coil were nearly identical. Without azide, the number of “spontaneous” mutant colonies forming in the experimental field was not statistically significant from numbers of colonies not exposed to field effects. Experimental temperature variation of 2 °C had little effect on colony formation, and the enhanced production of revertant colonies in the presence of the magnetic field was maintained during continued culture for 5 additional days. © 1994 Wiley‐Liss, Inc.
Microwave irradiation affects radial‐arm maze performance in the rat
Authors: Lai Henry , Horita Akira , Guy Arthur W. 
Published: February 2006

AbstractAfter 45 min of exposure to pulsed 2450 MHz microwaves (2 μsec pulses, 500 pps, 1 mW/cm2, average whole body SAR 0.6 W/kg), rats showed retarded learning while performing in the radial‐arm maze to obtain food rewards, indicating a deficit in spatial “working memory” function. This behavioral deficit was reversed by pretreatment before exposure with the cholinergic agonist physostigmine or the opiate antagonist naltrexone, whereas pretreatment with the peripheral opiate antagonist naloxone methiodide showed no reversal of effect. These data indicate that both cholinergic and endogenous opioid neurotransmitter systems in the brain are involved in the microwave‐induced spatial memory deficit. © 1994 Wiley‐Liss, Inc.
Magnetic fields alter electrical properties of solutions and their physiological effects
Authors: Ayrapetyan Sinerik N. , Grigorian Khachik V. , Avanesian Arpat S. , Stamboltsian Khachik V. 
Published: February 2006

AbstractCalcium chloride and snail physiological salt solutions were exposed to static magnetic fields (2.3–350 mT), and the physical properties of the solutions as well as their biologic effects were studied. Our preliminary observations show that these fields alter physicochemical properties of CaCl2 solutions and the functional effects of physiological solutions. Experiments on CaCl2 solutions demonstrated field‐dependent changes of electrical conductivity, with the magnitude and the direction of conductivity change being a function of both concentration and field intensity. The changes in conductivity were maintained for periods in excess of 1 h after exposure. Conductivity changes were not found after exposure of physiological solutions to static magnetic fields, but changes of biological consequence did occur. Other experiments showed that there were several changes in cellular function observed in ganglia and isolated neurons of Helix pomatia when the perfusing medium was changed from the normal physiologic solution to the same solution after exposure to magnetic fields. These changes include membrane depolarization and increased action potential discharge, reduced uptake of Ca into cells, altered content of cyclic nucleotides in ganglia, and increased volume of isolated cell bodies. A change in hydration of calcium ions may be one of the consequences of magnetic‐field exposure, and in physiological solutions this change may have functional consequences. © 1994 Wiley‐Liss, Inc.
Influence of microwaves on different types of receptors and the role of peroxidation of lipids on receptor‐protein shedding
Authors: Philippova T. M. , Novoselov V. I. , Alekseev S. I. 
Published: February 2006

AbstractThe effects of a continuous wave or pulse‐modulated, 900 MHz microwave field were studied by in vitro assays of rat chemoreceptors. The pulsed field was modulated as rectangular waves at rates of 1, 6, 16, 32, 75, or 100 pps. The pulse‐period to pulse‐duration ratio was 5 in all cases, and specific absorption rates (SARs) ranged from 0.5 to 18 W/kg. Binding of ligands to cell membranes was differentially affected by exposure to microwaves. For example, binding of H3‐glutamic acid to hippocampal cells was not altered by a 15 min exposure to a continuous wave field at 1 W/kg, but binding of H3‐dihydroalprenolol to liver‐cell membranes of neonates underwent a fivefold decrease under the same field conditions. This effect was not dependent on modulation or on a change in the constant of stimulus‐receptor binding but depended on a shedding of the membrane's receptor elements into solution. The magnitude of inhibition correlated with the oxygen concentration in the exposed suspension. Antioxidants (dithiothreitol and ionol) inhibited the shedding of receptor elements. The microwave exposure did not cause an accumulation of products from the peroxidation of lipids (POL). Ascorbate‐dependent or non‐enzymatic POL was not responsible for the inhibition, and POL was not found in other model systems. However, enzymatic POL mechanisms in localized areas of receptor binding remain a possibility. © 1994 Wiley‐Liss, Inc.
Protection against focal cerebral ischemia following exposure to a pulsed electromagnetic field
Authors: Grant Gerald , Cadossi Ruggero , Steinberg Gary 
Published: February 2006

AbstractThere is evidence that electromagnetic stimulation may accelerate the healing of tissue damage following ischemia. We undertook this study to investigate the effects of low frequency pulsed electromagnetic field (PEMF) exposure on cerebral injury in a rabbit model of transient focal ischemia (2 h occlusion followed by 4 h of reperfusion). PEMF exposure (280 V, 75 Hz, IGEA Stimulator) was initiated 10 min after the onset of ischemia and continued throughout reperfusion (six exposed, six controls). Magnetic resonance imaging (MRI) and histology were used to measure the degree of ischemic injury. Exposure to pulsed electromagnetic field attenuated cortical ischemic edema on MRI at the most anterior coronal level by 65% (P < 0.001). On histologic examination, PEMF exposure reduced ischemic neuronal damage in this same cortical area by 69% (P < 0.01) and by 43% (P < 0.05) in the striatum. Preliminary data suggest that exposure to a PEMF of short duration may have implications for the treatment of acute stroke. © 1994 Wiley‐Liss, Inc.
Simplification of the Wertheimer‐Leeper wire code
Authors: Kaune William T. , Savitz David A. 
Published: February 2006

AbstractWire codes, introduced by Wertheimer and Leeper as a surrogate for residential magnetic fields, divide imputed exposure into several categories based on the configurations of electrical wiring within 40 m of homes. Using the data set gathered by Savitz et al. in the Denver, Colorado, area of the United States, we determined which of the wiring attributes that contribute to Wertheimer‐Leeper coding are actually associated with lowpower magnetic fields measured in bedrooms of subjects. The results led us to propose a considerably simplified three‐category form of the Wertheimer‐Leeper code that 1) drops the distinctions between thick and thin primary wires and between first‐span and other secondary lines, 2) adds a new distinction between open (i.e., conductors not in physical contact) and spun secondaries, and 3) explains as much of the between‐home variability in log‐transformed bedroom fields as does the five categories of the original Wertheimer‐Leeper code. The data necessary to classify residences using the modified code are considerably simpler to obtain and should lead to more reliable results. A separate reanalysis of the Denver data set of Savitz et al. shows that the modified code yields risk estimates that are both precise and markedly elevated for the highest exposure category, suggesting that this code may be useful in other studies. © 1994 Wiley‐Liss, Inc.