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  • Occupational Health and Environmental Toxicology  (48)
  • Wiley-Blackwell  (48)
  • Wiley
  • 1995-1999
  • 1985-1989  (48)
  • 1980-1984
  • 1925-1929
  • 1986  (48)
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  • Wiley-Blackwell  (48)
  • Wiley
Years
  • 1995-1999
  • 1985-1989  (48)
  • 1980-1984
  • 1925-1929
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  • 1
    Electronic Resource
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    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 7 (1986), S. 387-394 
    ISSN: 0197-8462
    Keywords: mitogenic response ; peripheral blood mononuclear cells ; extremely-low-frequency magnetic fields ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effect of extremely-low-frequency pulsed magnetic fields (PMF) on the response of human peripheral blood mononuclear cells to mitogenic stimulation is reported. We investigated 25 healthy control subjects. Mitogen-stimulated mononuclear cells were exposed to PMF for 72 h and an inhibition of 3H-thymidine uptake was observed in all but one subject. The degree of inhibition of 3H-thymidine uptake was as much as 60%. There was no significant difference between the blastogenic responses of mononuclear cells exposed to PMF for 12 h and control cultures. This study establishes an inhibitory effect of PMF on an in vitro measure of immune function.
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  • 2
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    Bioelectromagnetics 7 (1986), S. 425-434 
    ISSN: 0197-8462
    Keywords: extremely low frequency electric field ; central nervous system ; electrophysiology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of 50-, 30-, and 15-Hz electric field exposure on the activity of spontaneously firing neurons in the brain of anaesthetized rats were studied. Exposure to fields of 100 V/m (peak-to-peak, in air) produced no effect on the overall rate of neuronal firing, but some synchronicity with the period of the exposure waveform was seen with 15- and 30-Hz electric fields.
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  • 3
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    Bioelectromagnetics 7 (1986), S. 1-11 
    ISSN: 0197-8462
    Keywords: ion exposure chamber ; ion concentration ; current density ; electric field ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Ion exposure chambers that have been designed and tested for use in biological and behavioral research with small animals are described in this report. The chambers exhibit an acceptable degree of uniformity in ion concentration, current density, and electric field within the exposure area. Gaseous by-products of corona discharge (O3 and NO2) have been measured and found to be 〈 .01 ppm and 〈 .1 ppm, respectively. Filtered air is fed to the individual exposure chambers, and temperature and humidity are well controlled. Noise due to corona and the air delivery system has been measured.
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  • 4
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    Bioelectromagnetics 7 (1986), S. 31-43 
    ISSN: 0197-8462
    Keywords: dielectric properties ; brain tissues ; changes ; radiofrequencies ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The dielectric properties of the bovine brain grey and white matter in the frequency range from 20 kHz to 100 MHz were measured at different times following animal death. Changes in the dielectric parameters versus time are interpreted in terms of the reduction of the cell volume fraction that results from either cell disintegration or cell size reduction. Good agreement between the computer fitted parameters and the values calculated from the Maxwell-Wagner model of the static dielectric constants was found. At frequencies above 1 MHz the changes of the dielectric properties are less pronounced, confirming earlier observations made by other investigators for different species.
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  • 5
    ISSN: 0197-8462
    Keywords: swimming endurance ; microwaves ; development ; behavior ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rats exposed to microwaves prenatally (2,450 MHz, 10 mW/cm2, 3 h/day, days 5-20 of gestation) or perinatally (same as above plus days 2-20 postnatally) were examined by a neurobehavioral test battery on postnatal days 30 and 100. Body mass, locomotor activity, startle to acoustic and air-puff stimuli, fore- and hindlimb grip strength, negative geotaxis, reaction to thermal stimulation, and swimming endurance were assessed. The prenatally and the perinatally exposed rats (male and female) weighed more than sham-exposed rats at 30, but not at 100, days of age. In addition, the perinatally exposed animals had less swimming endurance at 30, but not at 100, days of age relative to sham-exposed rats. For the other measures, only the air-puff startle response was altered and was limited to the prenatally exposed female pups; ie, at postnatal day 30, the startle response was increased in magnitude, and at postnatal day 100, the response was decreased. No other reliable effects were observed. In a second experiment, rats treated as described above were examined for alterations in body mass, locomotor activity, reaction to air-puff stimuli, reaction to thermal stimulation, and swimming endurance at postnatal days 30-36. Again, perinatally exposed rats were larger in body mass and had less swimming endurance compared with sham-exposed rats. The latency to the air-puff startle response was longer in female pups exposed prenatally. These data indicate that altered endurance and gross motor activity result from perinatal exposure to microwave irradiation.
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  • 6
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    Bioelectromagnetics 7 (1986), S. 163-176 
    ISSN: 0197-8462
    Keywords: dipole coupling ; electrical images ; low frequency ; SAR ; internal field ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The specific absorption rate (SAR) in a biological sample irradiated by electromagnetic fields between the metal plates of a transmission line can be altered significantly by the spacing of the metal plates and the distance between neighboring samples. The SAR in spherical biological samples is calculated for a number of neighboring sample arrangements and metal-plate spacings by using the method of images and induced dipole coupling. For a decrease in metal-plate spacing, the derived equations predict an increase in SAR within a sample and a decrease in SAR with a decrease in neighboring-sample spacing. The calculations are compared with measurements made with the aid of an array of 1-in radius metal hemispheres on the lower plate of two parallel plates (thus forming an image system). The hemisphere on which measurements are taken is insulated from the metal plate and is connected via a coaxial center conductor to an HP 3582A spectrum analyzer that measures the voltage and hence the electric field intensity at the hemisphere. Measurements made at a frequency where wavelength is large compared with sample size (48 Hz) are in good agreement with calculations.
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  • 7
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    Bioelectromagnetics 7 (1986), S. 235-237 
    ISSN: 0197-8462
    Keywords: microwaves ; hyperthermia ; chromosome aberration ; sister chromatid exchanges ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Specimens of human blood were exposed to 0, 4, 40, 100, and 200 Wkg-1 of 2.45 GHz microwave radiation for 20 minutes. The blood temperature was carefully controlled so that it rose from 37 to 40°C. Cultured lymphocytes were examined for induced chromosomal damage but no effect in excess of background was observed.
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  • 8
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    Bioelectromagnetics 7 (1986) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 9
    ISSN: 0197-8462
    Keywords: microwave ; 2450 MHz ; brain temperature ; rat ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In an effort to understand microwave heating better, regional brain and core temperatures of rats exposed to microwave radiation (2450 MHz) or elevated air temperatures were measured in two studies. In general, we have found no substantial evidence for temperature differentials, or “hot spots,” in the brain of these animals. In the first study, after a 30-min exposure, no temperature differences between brain regions either after microwave or ambient air exposure were found. However, a highly significant correlation between brain and core temperatures was found and this correlation was the same for both microwave and ambient air heating. In the second study, time-temperature profiles were measured in rats exposed to either 30 mW/cm2 or 36.2°C. In this study, the 30-min exposure period was divided into seven intervals and the change in temperature during each period was analyzed. Only the cortex showed significantly different heating rates between the air heating and microwave heating; however, this difference disappeared after the initial 5 min of exposure.
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  • 10
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    Bioelectromagnetics 7 (1986), S. 307-314 
    ISSN: 0197-8462
    Keywords: ATP ; respiration rate ; electromagnetic fields ; electric fields ; magnetic fields ; Physarum ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We have previously reported that exposing the vegetative plasmodia stage of Physarum polycephalum to either individual or simultaneously applied electric and magnetic fields (45-75 Hz, 0.14-2.0 G, and 0.035-0.7 V/m) lengthens their mitotic cycle, depresses their rate of reversible shuttle streaming, and lowers their respiration rate. In this article we report the effects of simultaneously applied electromagnetic fields (60 Hz, 1.0 G, 1.0 V/m), electric fields only (60 Hz, 1.0 V/m), magnetic fields only (60 Hz, 1.0 G) on the haploid amoeba of Physarum exposed for 120-180 days. Statistically significant depressions (about 8-11%) in ATP levels were observed with all field conditions; however, respiration was significantly decreased only when amoebae were subjected to either combined fields or electric fields alone. Magnetic fields alone failed to induce a significant decrease in respiration.
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  • 11
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    Bioelectromagnetics 7 (1986) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 12
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    Bioelectromagnetics 7 (1986), S. 369-379 
    ISSN: 0197-8462
    Keywords: DC transmission ; space charge ; static electric field ; potential gradient ; small air ions ; charged aerosols ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The Minnesota Environmental Quality Board completed a 3-year study of the space charge plume outside the right of way of a bipolar ( +/- 400 kV) direct current transmission line in rural west central Minnesota. The purpose of the study was to determine the levels of DC potential gradient and small air ions in the downwind plume to which humans and animals may be exposed. Potential gradient measurements show that a space charge plume is detectable downwind at least 1600 m from the transmission line. Plume relaxation rates indicate that under certain conditions one could detect the plume at twice that distance or more. Net charge in the plume assumes the polarity of the downwind energized transmission line conductor. The bipolar DC line thus electrically bisects the land through which it passes; on one side of the line there is a net positive space charge, on the other side a net negative space charge. Electric charge in the plume resides on aerosols and small air ions. Polar conductivity data substantiate the fact that small air ions of one polarity in the plume are elevated while those of opposite polarity are suppressed compared to background concentrations found in the rural environment. The resulting charge imbalance persists downwind at least 1600 m, though the median small air ion concentrations of plume polarity have adjusted to within the background range by that time with perpendicular wind speed components between 1 and 6 m/sec.
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  • 13
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    Bioelectromagnetics 7 (1986), S. 405-414 
    ISSN: 0197-8462
    Keywords: temperature ; hyperthermia ; Evans-blue ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The combined effects of ethanol and microwaves on the permeation of Evans blue dye through the mammalian blood-brain barrier was studied in male Wistar rats. Anesthetized rats were infused through a cannula in the left femoral vein with 0.1, 0.3, 0.5 or 0.7 grams of absolute ethanol per kilogram of body mass. A control group was given 0.7 g/kg of isotonic saline. The left hemisphere of the brain was irradiated by 3.15-GHz microwave energy at 3.0 W/cm2 rms for 15 min. The rat's rectal temperature was maintained at 37.0°C. Immediately after irradiation, 2% Evans blue dye in saline (2.0 ml/kg body mass) was injected through the cannula. The results show that as the quantity of alcohol was increased, the degree of staining was decreased or eliminated. The temperature of the irradiated area of the brain increased for the first 4 to 5 minutes of irradiation and then stabilized for the remainder of the irradiation period. The steady-state temperature was highest in animals receiving saline or the smallest dose of alcohol. As the quantity of alcohol was increased, the steady-state temperature was reduced. These results indicate that ethanol inhibits microwave-induced permeation of the blood-brain barrier through reduced heating of the brain.
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  • 14
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    Bioelectromagnetics 7 (1986), S. 349-357 
    ISSN: 0197-8462
    Keywords: 60 Hz ; cyclotron resonance ; timing discrimination ; multiple schedule ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The present study demonstrates that operant behavior is affected by a combination of a 60-Hz magnetic field and a magnetostatic field 2.6 × 10-5T (about half the geomagnetic field). Rats exposed to this combination for 30 min consistently exhibited changes in the rate and pattern of responding during the differential reinforcement of low rate (DRL) component of a multiple fixed ratio (FR) DRL reinforcement schedule. By contrast, there were no measurable changes following exposure to the static field alone or to the oscillating field alone, even with a 10-fold increase in intensity (5 × 10-5 to 5 × 10-4 Trms). A cyclotron resonance mechanism has been suggested as a possible explanation for the observation that weak static magnetic fields modify the response of in vitro brain tissue to low-frequency magnetic fields. The choice of static field intensity Bo and frequency v in the present study follows from the cyclotron resonance condition v = (1/2π)(q/m)Bo, for singly charged lithium, an element in extensive use in the clinical treatment of affective disorders in humans. The present research is consistent with a cellular cyclotron resonance mechanism and tends to imply a functional dependence of behavior on the geomagnetic field.
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  • 15
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    Bioelectromagnetics 7 (1986), S. 107-107 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
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  • 16
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    Bioelectromagnetics 7 (1986), S. 129-140 
    ISSN: 0197-8462
    Keywords: dosimetry ; closed waveguide system ; microwave cataractogenesis ; rabbits ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A closed waveguide method has been used to induce opacities in the rabbit eye. A 30-min exposure to 2.45-GHz radiation such that 8.7 W is incident on the head (5.75 W being absorbed) produces a cataract in half of the exposed eyes of New Zealand white rabbits.
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  • 17
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    Bioelectromagnetics 7 (1986) 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 18
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
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  • 19
    ISSN: 0197-8462
    Keywords: dielectric methods ; water ; water of hydration ; myoglobin ; polyvinylpyrrolidone (PVP) ; human low-density lipoprotein (LDL) ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The dielectric behavior of the aqueous solutions of three widely differing macromolecules has been investigated: myoglobin, polyvinylpyrrolidone (PVP), and human serum low-density lipoprotein (LDL). It was not possible to interpret unambiguously the dielectric properties of the PVP solution in terms of water structure. The best interpretation of the dielectric data on the myoglobin and LDL solutions was that, in both cases, the macromolecule attracts a layer of water of hydration one or two water molecules in width. For LDL, this corresponds to a hydration factor of only 0.05 g/g, whereas for myoglobin the figure is nearer 0.6 g/g. With myoglobin, part of the water of hydration exhibits its dispersion at frequencies of a few GHz, and the rest disperses at lower frequencies, perhaps as low as 10-12 MHz. The approximate constancy of the width of the hydration shell for two molecules as dissimilar in size as LDL and myoglobin confirms that the proportion of water existing as water of hydration in a biological solution depends critically on the size of the macromolecules as well as on their concentration.
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  • 20
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    Bioelectromagnetics 7 (1986), S. 191-207 
    ISSN: 0197-8462
    Keywords: electric current ; electrical wires ; magnetic fields ; cancer ; children ; epidemiology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The magnetic fields from overhead power lines and other electromagnetic sources were determined at the birth and diagnosis dwellings of all tumor cases reported in the county of Stockholm during the years 1958-73 for individuals 0-18 years of age. The study was limited to 716 cases having a permanent address in the county both at time of birth and diagnosis. An equivalent number of controls was matched to the cases according to church district of birth, age, and sex. Outside each dwelling, the occurrence of visible electrical constructions (6-200-kV high-voltage wires, substations, transformers, electric railroads, and subways) within 150 m of the dwelling was noted. Also, the 50-Hz magnetic field was measured outside the main entrance of the dwelling. Visible 200-kv wires were noted at 45 of 2,098 dwellings and were found twice as frequently among cases as among controls (P 〈 .05). The magnetic field measured at the dwelling varied between 0.0004 to 1.9 μT (mean value 0.069 μT). The magnetic field was higher (0.22 μT) at dwellings with visible 200-kV wires than at those without such wires. Magnetic fields of 0.3 μT or more were measured at 48 dwellings, and were found twice as frequently among cases as among controls (P 〈 .05). The difference was most pronounced for dwellings of nervous system tumors and was less for leukemias.
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  • 21
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    Bioelectromagnetics 7 (1986), S. 223-233 
    ISSN: 0197-8462
    Keywords: heart rate ; body temperature ; hematology ; rats ; microwaves ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In this study the influence of acute (6 hr) exposure to 2450 MHz (CW) microwave radiation on certain cardiovascular, biochemical, and hematologic indices was examined in unanesthetized rats. Under methoxyflurane anesthesia, a catheter was inserted into the right femoral artery, which was used for monitoring blood pressure, heart rate, and blood sampling. Colonic temperature was monitored via a VITEK thermistor probe inserted rectally to a depth of 5 cm. The rat was subsequently placed into a ventilated restraining cage which was located inside an anechoic chamber. The temperature and humidity in the chamber were maintained at 22 ± 0.5°C and 60 ± 5% (means ± S.E.), respectively, during the experimental period. Rats (60) were exposed to either 0 (sham) or 10 mW/cm2 (exposed) for 6 hr. During exposure rats were oriented perpendicular to the E-field, and the measured specific absorption rate (SAR) was 3.7 mW/g. In the sham and exposed rats, the preexposure (time 0) mean ± S.E. arterial blood pressure (MABP), heart rate, and colonic temperature were approximately 120 ± 5 mmHg, 450 ± 10 beats/min, and 37.0 ± 0.2 °C, respectively. In the sham-exposed rats these values remained stable throughout the 6-hr exposure period. In the exposed rats, no effects were noted on MABP or colonic temperature; however after 1 hr of exposure, a significant reduction in heart rate was noted (450 versus 400 beats/min). This decrease in heart rate persisted throughout the remainder of the exposure period. None of the hematologic or biochemical parameters examined were affected by the microwave exposure. Although other mechanisms may be responsible, this decrease in heart rate may have been due to subtle cardiovascular adjustments because of microwave-induced heating with a resultant reduction in resting metabolic rate.
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  • 22
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    Bioelectromagnetics 7 (1986), S. 239-242 
    ISSN: 0197-8462
    Keywords: 60 Hz ; electric fields ; pineal gland ; circadian rhythm ; melatonin ; serotonin N-acetyl transferase (SNAT) ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rats exposed for 3 weeks to uniform 60-Hz electric fields of 39 kV/m (effective field strength) failed to show normal pineal gland circadian rhythms in serotonin N-acetyl transferase activity and melatonin concentrations. The time required for recovery of the melatonin rhythm after cessation of field exposure was determined to be less than 3 days. The rapid recovery suggests that the overall metabolic competence of the pineal is not permanently compromised by electric-field exposure, and that the circadian rhythm effect may be neuronally mediated.
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  • 23
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    Bioelectromagnetics 7 (1986), S. 283-293 
    ISSN: 0197-8462
    Keywords: ultrasound immunosuppression ; natural killer (NK) cells ; hamster immune system ; hyperthermia ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The effects of in vivo ultrasound irradiation of the spleen on immunological functions were assessed with an in vitro natural killer (NK) cell cytotoxic assay. Anesthetized hamsters were exposed to 1 MHz ultrasound at intensity levels currently being used clinically for therapeutic diathermy and hyperthermia (1-5 W/cm2, for 500 sec with constant beam scanning). Hyperthermic levels in the spleen ranged from 38-43°C. Significant depression of natural killer (NK) cell activity was seen 4 h after spleen irradiation as compared to sham irradited and normal animals. A return towards normal levels was observed in experimental groups at 24 h after exposure. Sham and normal animals were not significantly different in NK activity, indicating no significant stress-related immunosuppressive effects due to handling. Differential leukocyte counts taken for each exposure condition showed significant lymphopenia at 4, 8, and 16 h after exposure, near normal levels at 24 h, and complete recovery by 48 h. The number of circulating mononuclear cells at 4 h showed a dose-related suppression as the exposure intensities were increased.
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  • 24
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    Bioelectromagnetics 7 (1986), S. 347-347 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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  • 25
    ISSN: 0197-8462
    Keywords: microwave exposure ; behavior ; physiology ; pathology ; blood chemistry ; neurobehavioral toxicology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Long-Evans male adult rats were intermittently exposed for 14 weeks to continuous wave (CW) 2450-MHz microwaves at an average power density of 2.5 mW/cm2. The mean specific absorption rate was 0.70 W/kg (± 0.02 SEM). The rats were exposed 7 h/day, 7 days/week in a radiation chamber with a monopole above ground, while housed in Plexiglas cages. Weekly measures of body mass and food intake did not indicate statistically significant effects of microwave irradiation. Assessments of threshold for electric-footshock detection revealed a significant difference between microwave and sham-exposed animals. Assessments of cholinesterase and sulfhydryl groups in blood and 17-ketosteriods in urine did not distinguish the two groups of rats. Behavioral measures made at the end of the 14-week exposure included an open-field test, shuttlebox avoidance performance, and schedule-controlled lever-pressing for food pellets. Statistically significant differences between microwave- and sham-exposed rats were observed for these measures. Examination of adrenal tissue, plasma electrolytes, and organ masses after 14 weeks of exposure revealed no difference between the two groups of rats.
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    Bioelectromagnetics 7 (1986), S. 341-346 
    ISSN: 0197-8462
    Keywords: stationary magnetic fields ; homogeneous and gradient fields ; superconducting magnet ; mice ; rats ; thermoregulation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Rectal temperatures were recorded in mice and rats during exposure to a stationary 7.55 Tesla (1 T = 104 Gauss) homogeneous magnetic field, and to magnetic field gradients ranging from 58.1-58.6 T/m. Contrary to observations reported recently by other investigators, no evidence was found for a change in the body temperature of rodents exposed to strong homogeneous or gradient magnetic fields.
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  • 27
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    Bioelectromagnetics 7 (1986) 
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    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
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    Bioelectromagnetics 7 (1986), S. 23-29 
    ISSN: 0197-8462
    Keywords: electromagnetic fields ; transcriptional increases ; polytene chromosomes ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We previously showed that quasirectangular, asymmetrical, pulsed electromagnetic (EM) fields of low frequency can induce increased transcription in Sciara salivary gland cells. A symmetrical sine wave with the same frequency as known biologically effective asymmetric signals was studied in the present investigations. The results demonstrated that signal shape was not a major factor in causing augmented transcription. The pattern of grain density in transcription autoradiograms, as well as the size classes of RNA responsive to EM fields, was the same irrespective of asymmetry or symmetry of the signal. Following short-term exposure of the cells to either type of EM field, S values of new transcripts were consistent with those expected for processed and unprocessed messenger RNA.
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  • 29
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    Bioelectromagnetics 7 (1986), S. 83-90 
    ISSN: 0197-8462
    Keywords: RF induction heaters ; magnetic field strength monitor ; occupational RF exposures ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We discuss initial magnetic field strength measurements made around radiofrequency (RF) induction heaters. These measurements were made with a monitor developed for the National Institute for Occupational Safety and Health (NIOSH) by the National Bureau of Standards (NBS). The monitor has a dynamic range of .01 to 10,000 A2/m2, a frequency range of 300 kHz to 100 MHz, an isotropic response (± .3 dB) with three mutally orthogonal loop antennas that have the ability to measure and display each of three orthogonal magnetic field components, a high probe burnout protection level of 20,000 A2/m2, and an accuracy of ± 1.0 dB at 13 calibration frequencies. The portable survey monitor was used to measure the magnetic field strengths in the vicinity of 16 RF induction heaters. Typically these induction heaters are operated continuously for several hours. The maximum field strengths (without duty factor correction) ranged from 15 to 4,500 A2/m2 and were measured 5 to 51 cm from the loop applicators of the induction heaters. At locations commonly occupied by workers (ie, approximately 30 to 76 cm from heaters), the fields ranged from .01 to 300 A2/m2 (without duty factor correction).
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  • 30
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    Bioelectromagnetics 7 (1986), S. 91-94 
    ISSN: 0197-8462
    Keywords: microwaves ; immunology ; antibody response ; mice ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Female CD-1 mice immunized against the bacterium Streptococcus pneumoniae type III were exposed to 9-GHz pulsed microwaves (pulse repetition rate 970-1,000, pulse width 1.0 μs, peak power 1 W/cm2) at an average incident power density of 1 mW/cm2 (calculated SAR = 0.47 W/kg) for 2 h per day for 5 days. Circulating antibody titers for the microwave-exposed animals were not significantly different from those of the shamirradiated animals, and there were no differences in any of the hematological parameters analyzed, indicating that 9-GHz pulsed microwaves at 1 mW/cm2 do not alter the immune response of mice immunized against S pneumoniae.
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  • 31
    ISSN: 0197-8462
    Keywords: microwaves ; spider webs ; behavior ; 9.6-GHz pulsed radiation ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Eight cross spiders (Araneus diadematus) were exposed overnight (16 h) during web-building activity to pulsed 9.6-GHz microwaves at average power densities of 10, 1, and 0.1 mW/cm2 (estimated SARs 40, 4, and 0.4 mW/g). Under these conditions, 9.6-GHz pulsed microwaves did not affect the web-spinning ability of the cross spider.
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  • 32
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    Bioelectromagnetics 7 (1986), S. 109-112 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 33
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    Bioelectromagnetics 7 (1986), S. 141-149 
    ISSN: 0197-8462
    Keywords: radiofrequency radiation ; 27.12 MHz ; hyperthermia ; birth defects ; teratology ; embryo ; rat ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Five groups of pregnant Sprague-Dawley rats were irradiated for 10-40 min on gestation day 9 in a 27.12-MHz radiofrequency field at a magnetic field strength of 55 A/m and an electric field strength of 300 V/m. The specific absorption rate was 10.8 ± 0.3 W/kg. Exposures were terminated after the rat's colonic temperature reached 41.0°C, 41.5°C, 42.0°C, 42.5°C, or 43.0°C. A control group was sham irradiated at 0 A/m and 0 V/m on gestation day 9, whereas a second control group was untreated. The incidence of both birth defects and prenatal death was directly related to maternal body temperature once a temperature threshold was exceeded. The temperature threshold for both types of effects was approximately 41.5°C. A few pregnant rats died after exposure to 43.0°C, and higher temperatures were nearly always lethal.
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  • 34
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    Bioelectromagnetics 7 (1986), S. 177-189 
    ISSN: 0197-8462
    Keywords: cyclotron resonance ; ion channels ; weak electromagnetic field effects ; ELF bioeffects ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We seek to extend the recent suggestion that classical cyclotron resonance of biologically important ions is implicated in weak electromagnetic field-cell interactions. The motion of charged particles in a constant magnetic field and periodic electric field is examined under the simplifying assumption of no damping. Each of the nine terms of the relative dielectric tensor is found to have a dependence on functions that include the factor (ω2 - ω)-1, where ωB is the gyrofrequency. We also find a plasmalike decomposition of the electric field into oppositely rotating components that could conceivably act to drive oppositely charged ions in the same direction through helical membrane channels. For weak low-frequency magnetic fields, an additional feature arises, namely, periodic reinforcement of the resonance condition with intervals of the order of tens of msec for biological ions such as Li+, Na+, and K+.
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  • 35
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    Bioelectromagnetics 7 (1986), S. 209-221 
    ISSN: 0197-8462
    Keywords: brain tissue ; radiofrequency ; radiation ; dosimetry ; calcium ions ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This paper presents calculations for the electric field and absorbed power density distribution in chick brain tissue inside a test tube, using an off-center spherical model. It is shown that the off-center spherical model overcomes many of the limitations of the concentric spherical model, and permits a more realistic modeling of the brain tissue as it sits in the bottom of the test tube surrounded by buffer solution. The effect of the unequal amount of buffer solution above the upper and below the lower surfaces of the brain is analyzed. The field distribution is obtained in terms of a rapidly converging series of zonal harmonics. A method that permits the expansion of spherical harmonics about an off-center origin in terms of spherical harmonics at the origin is developed to calculate in closed form the electric field distribution. Numerical results are presented for the absorbed power density distribution at a carrier frequency of 147 MHz. It is shown that the absorbed power density increases toward the bottom of the brain surface. Scaling relations are developed by keeping the electric field intensity in the brain tissue the same at two different frequencies. Scaling relations inside, as well as outside, the brain surface are given. The scaling relation distribution is calculated as a function of position, and compared to the scaling relations obtained in the concentric spherical model. It is shown that the off-center spherical model yields scaling ratios in the brain tissue that lie between the extreme values predicted by the concentric and isolated spherical models.
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  • 36
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    Bioelectromagnetics 7 (1986), S. 259-269 
    ISSN: 0197-8462
    Keywords: dielectric spectroscopy ; parameters determination ; cell suspensions ; tissues ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A new method for finding the dielectric parameters of biological substances is presented. The method makes use of the loss-tangent as a function of frequency to identify the dominating relaxation process. The method was tested for a few cell suspensions (blood and lymphocytes) and two tissues (liver and spleen). The obtained parameters agree well with those calculated from Maxwell-Wagner theory (β dispersion).
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  • 37
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    Bioelectromagnetics 7 (1986), S. 13-22 
    ISSN: 0197-8462
    Keywords: seasonal patterns ; heat ; electromagnetic fields ; abortion ; fetal growth ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Seasonal patterns were seen in fetal growth and in abortion rate for families using electrically heated beds. These patterns could be attributed to the seasonal use of heated beds. The fact that such seasonal patterns were seen only in users, and not in nonusers, of electrically heated beds suggests that electrical bed heating may have a direct effect on fetal development. The effect could be due to excessive heat or to electromagnetic field exposure.
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  • 38
    ISSN: 0197-8462
    Keywords: microwaves ; rats ; behavior ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Adult male Long-Evans rats were intermittently exposed to 2450 MHz CW microwaves at an average power density of 0.5 mW/cm2 for 90 days. The resulting SAR was 0.14 W/kg (range 0.11 to 0.18 W/kg). The animals were exposed 7 h/day, 7 days/wk, for a total of 630 h in a monopole-above-ground radiation chamber while housed in Plexiglas holding cages. Daily measures of body mass and food and water intake indicated no statistically significant effects of microwave exposure. Monthly assessment of reactivity to electric footshock, levels of cholinesterase and sulfhydryl groups in blood, and 17-ketosteroids in urine revealed no reliable differences between 14 sham-exposed and 14 microwave-exposed rats. After the 90 days of exposure, seven rats, randomly chosen from each group, were assessed for open-field behavior, shuttlebox performance, and schedule-controlled (IRT schedule) lever pressing for food pellets. Statistically significant differences between microwave-exposed and sham-exposed rats were observed in shuttlebox performances and lever pressing. Post mortem measures of mass of several organs and microscopic examination of adrenal tissue revealed no differences between the two groups of animals.
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  • 39
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    Bioelectromagnetics 7 (1986), S. 73-81 
    ISSN: 0197-8462
    Keywords: permittivity measurement ; dielectric properties ; eye lens ; bound water ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The relative permittivity and conductivity of rabbit eye lens were measured in the frequency domain between 2 and 18 GHz at temperatures of 37 and 20°C. An analysis of the data suggested that a significant proportion of the bulk water in nuclear and cortical lens tissue may behave differently to pure water. In addition, the Maxwell-Fricke mixture theory was used to estimate the amount of hydrated water that relaxes far below 1 GHz.
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  • 40
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    Bioelectromagnetics 7 (1986), S. 95-99 
    ISSN: 0197-8462
    Keywords: conductivity ; culture medium ; electric fields ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Few studies are available that relate conductivity and temperature in solutions commonly used in tissue culture media. The purpose of this paper is to provide equations relating conductivity and temperature (in the range 20°C-40°C) for five solutions: 0.9% saline, MEM (Minimum Essential Media), horse serum, MEM with 1% horse serum, and MEM with 10% horse serum.
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  • 41
    ISSN: 0197-8462
    Keywords: 60-Hz electromagnetic fields ; chromosome damage ; mitotic rate ; in vitro ; human peripheral lymphocytes ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Dividing human peripheral lymphocytes from 10 normal adults (5 males and 5 females) were exposed in vitro to low level 60-Hz electromagnetic fields for 69 hours. The current density of the electrical field was 30 μA/cm2, while the magnetic field was either 1 or 2 gauss. The cytological endpoints measured were mitotic rate and chromosome breakage. No statistically significant differences, indicative of a field effect, were observed between treated and control cells whether exposed to an electric field, a magnetic field, or to various combinations of the two.
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  • 42
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    Bioelectromagnetics 7 (1986), S. 395-404 
    ISSN: 0197-8462
    Keywords: hair receptors ; afferent impulses ; neurophysiology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: There are two possible mechanisms of effects of large electric fields on animals, one caused by the electric field at the body surface and the other caused by the electric current induced inside the body. The purpose of the present experiments was to investigate the former possibility by recording action potentials from afferent fibers innervating various sensory receptors in the cat's hindlimb. Cat hairs were attracted to the upper electrode when exposed to DC electric fields of 180 kV/m or greater, and action potentials were evoked in the afferent fibers innervating G1, G2, and down hair receptors. No action potentials were evoked in afferent fibers innervating type I, type II, field receptors, muscle spindles, or joint receptors. These results indicate that a strong DC electric field induced movement of the hairs, eventually evoked excitation of the hair receptors, but that other receptors located under the skin were not influenced by electric field exposure.
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  • 43
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    Bioelectromagnetics 7 (1986), S. 295-306 
    ISSN: 0197-8462
    Keywords: mechanical vibration ; electrostrictive force ; flectric field ; brain tissue ; extremely low frequencies ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Electromagnetic fields can interact with biological tissue both electrically and mechanically. This study investigated the mechanical interaction between brain tissue and an extremely-low-frequency (ELF) electric field by measuring the resultant vibrational amplitude. The exposure cell is a section of X-band waveguide that was modified by the addition of a center conductor to form a small TEM cell within the waveguide structure. The ELF signal is applied to the center conductor of the TEM cell. The applied ELF electric field generates an electrostrictive force on the surface of the brain tissue. This force causes the tissue to vibrate at a frequency equal to twice the frequency of the applied sinusoidal signal. An X-band signal is fed through the waveguide, scattered by the vibrating sample, and detected by a phase-sensitive receiver. Using a time-averaging spectrum analyzer, a vibration sensitivity of approximately 0.2 nmp-p can be achieved. The amplitude of the brain tissue vibrational response is constant for vibrational frequencies below 50 Hz; between 50 and 200 Hz resonant phenomena were observed; and above 200 Hz the amplitude fall-off is rapid.
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    Bioelectromagnetics 7 (1986), S. 381-386 
    ISSN: 0197-8462
    Keywords: magnetic fields ; brain ; calcium ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: 45Ca2+ efflux from neonatal isolated chick brains was measured. The brains were exposed to uniform or nonuniform static magnetic fields. The field intensity ranged from 200-900 mT. The exposure took place during incubation and/or when efflux was being measured. No difference appeared in the 45Ca2+ efflux between controls and exposed brains.
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    Bioelectromagnetics 7 (1986), S. 435-439 
    ISSN: 0197-8462
    Keywords: Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 46
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    Bioelectromagnetics 7 (1986), S. 271-281 
    ISSN: 0197-8462
    Keywords: magnetic fields ; extremely low frequency (ELF) magnetic fields ; neurotransmitter release ; motor end plate ; electrophysiology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A method for simultaneous magnetic field application and intracellular recording is presented. A little used method for magnetic field application was exploited; the field generator consisted of a flat copper sheet through which current was passed to generate a magnetic field. The resultant magnetic field was relatively homogeneous, exhibiting a variation of ± 5%. This compact, current-sheet field generator was mounted on the condensor of a microscope. The current induced in the intracellular electrode was reduced by injecting current equal and opposite to the induced current into the microelectrode. This step reduces the possibility of cellular effects and voltage artifacts due to the induced electrode current. The technique was used to conduct preliminary studies on the effects of extremely low frequency (ELF) linearly and circularly polarized magnetic fields (1.0 Gauss, 60 and 70 Hz) on miniature end plate potential (mepp) frequency (frequency of neurotransmitter release events) of rat flexor digitorum brevis muscle. The same synapse was utilized for both the sham-exposed control and the exposed experimental halves of an experiment. After 10 min of exposure to a 60-Hz linear field, mepp frequency was significantly increased by 12%, but exposure to a 60-Hz circular field did not significantly alter mepp frequency. Exposure to a 70-Hz linear field did not significantly change mepp frequency, but application of a 70-Hz circular field appears to decrease mepp frequency by 4%. These results indicate that both types of magnetic fields can alter mepp frequency, depending upon the frequency and configuration of the field.
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    Bioelectromagnetics 7 (1986), S. 329-339 
    ISSN: 0197-8462
    Keywords: air ions ; DC electric fields ; locomotor activity ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Air ions and direct current (DC) electric fields have been reported to exert subtle behavioral and biological effects on rodents and humans. These effects often appear inconsistent, yet there have been few attempts to resolve these inconsistencies by experimental replication. Rats exposed to negatively or positively charged air ions over a wide range of concentrations and exposure periods have been reported to show alterations in their level of locomotor activity. In this study, locomotor activity of Sprague-Dawley rats was quantified during exposure to either (1) unipolar air ions and DC fields of the same polarity or (2) DC fields alone. Both polarities were studied. Air ion concentrations were 5.0 × 103, DC fields were 3 kV/m, and exposures lasted 2, 18, or 66 h. In one experiment rats were exposed to DC fields of 12 kV/m. No exposure condition exerted any effect on locomotor activity or rearing behavior. In addition, no behavioral perturbations were observed after the onset of any of the exposure conditions, suggesting that the rats may have failed to detect the altered environment.
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    Bioelectromagnetics 7 (1986), S. 359-367 
    ISSN: 0197-8462
    Keywords: microwaves ; heartbeat ; chick embryo hearts ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiations with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37°C permitted heart survival. Samples were irradiatd at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the heart.
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