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  • 1
    Electronic Resource
    Electronic Resource
    Effects of 2.45-GHz microwave radiation and phorbol ester 12-O-tetradecanoylphorbol-13-acetate on dimethylhydrazine-induced colon cancer in mice (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 15 (1994), S. 531-538 
    Details
    ISSN: 0197-8462
    Keywords: cancer promotion ; initiation ; tumor incidence ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The purpose of this study was to investigate the effects of 2.45 GHz microwave (MW) radiation on dimethylhydrazine (DMH)-induced colon cancer in mice. The subjects were 115 Balb/c mice 4 weeks of age. The animals were divided into group A (control), group B (DMH), group C (DMH + MW), and group D [DMH + 12-O-tetradecanoylphorbol-13-acetate (TPA)]. Radiation (10 mW/cm2) was delivered dorsally with the E field parallel to the mouse's long body axis in an anechoic chamber. Radiations were administered 3 hr daily, 6 days per week, over a period of 5 months. The average SAR was estimated to be 10-12 W/kg. During the course of radiation treatments, DMH was injected once per week. The tumor promoter TPA was administered once per week for 10 weeks, from the third week on, after the initial treatment. The incidence of tumors did not significantly differ between the three test groups (groups B, C, and D; P 〉 0.25). However, the number of tumors, the size of the tumors, and the incidence of protuberant and infiltrative types in tumor-bearing animals were higher in group D compared to groups B and C (P 〈 0.05). No difference was found between groups B and C (P 〉 0.25). The study indicates that 2.45 GHz microwave radiation at 10 mW/cm2 power density did not promote DMH-induced colon cancers in young mice. The study also showed that TPA could accelerate colon tumor production if a tumor was initiated. © 1994 Wiley-Liss, Inc.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250150606
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  • 2
    Electronic Resource
    Electronic Resource
    Design of a magnetic field generator for experiments on magnetic effects in cell cultures (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 5 (1984), S. 399-410 
    Details
    ISSN: 0197-8462
    Keywords: magnet ; magnetic field ; tissue culture ; exposure system ; biological effects ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A magnetic field generator constructed of rare earth-cobalt magnets is proposed for examining the biological effects of static magnetic fields (less than 1 T) on tissue cultures. Important quantities of a magnetic field from a biological-effects viewpoint, ie, its strength and the product of strength and gradient, are analysed. A practical procedure for designing the generator with optimum parameters is given. Also, parameters are determined which will yield a sinusoidal spatial field distribution.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250050405
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  • 3
    Electronic Resource
    Electronic Resource
    Pulsed magnetic field from video display terminals enhances teratogenic effects of cytosine arabinoside in mice (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 70-74 
    Details
    ISSN: 0197-8462
    Keywords: video display terminals ; embryogenesis ; teratology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Eighty-nine Swiss Webster mice were randomly divided into four groups: a control group, a pulsed magnetic field (PMF) group, a cytosine arabinoside (ara-C, a teratogen) group, and, a combined PMF + ara-C group. Mice in the PMF and PMF + ara-C groups were irradiated with a PMF (a sawtooth waveform with 52 μs rise time, 12 μs decay time, and 15.6 kHz frequency) at a peak magnetic flux density of 40 μT for 4 hours daily on days 6-17 of gestation. The mice in the ara-C and the PMF + ara-C groups were injected intraperitoneally on day 9 of gestation with 10 mg/kg of ara-C. The incidence of resorption and dead fetuses was not affected by PMF but was increased by ara-C injection. The malformation incidence of cleft palate (CP) and/or cleft lip (CL) was significantly higher in all three of the treated groups than in the control group (P 〈 0.05). If, however, statistical analyses had been done on litters rather than on individual fetuses, they would show that the incidence of CP and/or CL in the PMF group is not significantly greater than that in the control group. A significantly higher incidence of CP and/or CL was found in the PMF + ara-C group (49%) than the ara-C alone group (26.1%). These data suggest that PMF might enhance the development of ara-C-induced CP and/or CL. The incidence of minor variations in skeletal development, including reduction of skeletal calcification and loss of skeleton, was not statistically significant in the PMF group. However, it was higher in the two ara-C-treated groups, and there was no significant difference between the ara-C alone group and the ara-C + PMF group. From these results it is concluded that the very weak embryotoxic effects of PMF exposure may be revealed and enhanced in combination with a teratogenic agent. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160113
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  • 4
    Electronic Resource
    Electronic Resource
    Circularly polarized, sinusoidal, 50 Hz magnetic field exposure does not influence plasma testosterone levels of rats (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 15 (1994), S. 513-518 
    Details
    ISSN: 0197-8462
    Keywords: subchronic exposure ; rotating magnetic fields ; neuroendocrine hormone ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We exposed rats to circularly polarized 50 Hz magnetic fields to determine if plasma testosterone concentration was affected. Previous experiments indicate that magnetic fields suppress the nighttime rise in melatonin, suggesting that other neuroendocrine changes might occur as well. Male Wistar-King rats were exposed almost continuously for 6 weeks to magnetic flux densities of 1,5, or 50 μT. Blood samples were obtained by decapitation at 12:00 h and 24:00 h. Plasma testosterone concentration showed a significant day-night difference, with a higher level at 12:00 h when studied in July and December, but the day-night difference disappeared when concentrations were studied in April. In three experiments, magnetic field exposure had no statistically significant effect on plasma testosterone levels compared with the sham-exposed groups. These findings indicate that 6 weeks of nearly continuous exposure to circularly polarized, 50 Hz magnetic fields did not change plasma testosterone concentration in rats. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250150604
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  • 5
    Electronic Resource
    Electronic Resource
    Theoretical analysis of magnetic field interactions with aortic blood flow (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 17 (1996), S. 21-32 
    Details
    ISSN: 0197-8462
    Keywords: blood flow ; static magnetic field ; magnetohydrodynamic interactions ; finite element analysis ; sinuatrial node ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: The flow of blood in the presence of a magnetic field gives rise to induced voltages in the major arteries of the central circulatory system. Under certain simplifying conditions, such as the assumption that the length of major arteries (e.g., the aorta) is infinite and that the vessel walls are not electrically conductive, the distribution of induced voltages and currents within these blood vessels can be calculated with reasonable precision. However, the propagation of magnetically induced voltages and currents from the aorta into neighboring tissue structures such as the sinuatrial node of the heart has not been previously determined by any experimental or theoretical technique. In the analysis presented in this paper, a solution of the complete Navier-Stokes equation was obtained by the finite element technique for blood flow through the ascending and descending aortic vessels in the presence of a uniform static magnetic field. Spatial distributions of the magnetically induced voltage and current were obtained for the aortic vessel and surrounding tissues under the assumption that the wall of the aorta is electrically conductive. Results are presented for the calculated values of magnetically induced voltages and current densities in the aorta and surrounding tissue structures, including the sinuatrial node, and for their field-strength dependence. In addition, an analysis is presented of magnetohydrodynamic interactions that lead to a small reduction of blood volume flow at high field levels above approximately 10 tesla (T). Quantitative results are presented on the offsetting effects of oppositely directed blood flows in the ascending and descending aortic segments, and a quantitative estimate is made of the effects of assuming an infinite vs. a finite length of the aortic vessel in calculating the magnetically induced voltage and current density distribution in tissue. © 1996 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Behavioral studies with mice exposed to DC and 60-Hz magnetic fields (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 5 (1984), S. 147-164 
    Details
    ISSN: 0197-8462
    Keywords: DC and 60-Hz magnetic fields ; animal behavior ; memory retention ; locomotor activity ; pentylenetetrazole sezure threshold ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Behavioral measures were evaluated in adult CD-1 and LAF-1 mice continuously exposed for 72 h to a 1.5-Tesla (1 T = 104 Gauss) homogeneous DC magnetic field, and in LAF-1 mice continuously exposed for 72 h to a sinusoidal 60-Hz, 1.65-mT (rms) homogeneous AC field. Three types of behavioral tests were employed: (1) Memory of an electroshock-motivated passive avoidance task was assessed in animals that had been trained immediately prior to the field exposure. The strength of memory was varied either by altering the strength of the electric footshock during training, or by administering a cerebral protein synthesis inhibitor, anisomycin, at the time of training. (2) General locomotor activity was measured using a quadrant-crossing test immediately after termination of the magnetic field exposure. (3) Sensitivity of the experimental subjects to the seizure-inducing neuro-pharmacological agent, pentylenetetrazole, was assessed immediately after the field exposure on the basis of three criteria: (a) the percentage of subjects exhibiting a generalized seizure, (b) the mean time to seizure, and (c) the mean seizure level. The results of these studies revealed no behavioral alterations in exposed mice relative to controls in any of the experimental tests with the 1.5-T DC field or the 60-Hz, 1.65-mT (rms) AC field.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250050204
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  • 7
    Electronic Resource
    Electronic Resource
    Simple method to measure power density entering a plane biological sample at millimeter wavelengths (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 8 (1987), S. 91-102 
    Details
    ISSN: 0197-8462
    Keywords: millimeter waves ; near-field measurement ; microwave power density ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A simple method for measuring microwave power density is described. It is applicable to situations where exposure of samples in the near field of a horn is necessary. A transmitted power method is used to calibrate the power density entering the surface of the sample. Once the calibration is available, the power density is known in terms of the incident and reflected powers within the waveguide. The calibration has been carried out for liquid samples in a quartz cell. Formulas for calculating specific absorption rate (SAR) are derived in terms of the power density and the complex dielectric constant of the sample. An error analysis is also given.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250080110
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  • 8
    Electronic Resource
    Electronic Resource
    ELF electromagnetic environment in power substations (1989)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 10 (1989), S. 51-64 
    Details
    ISSN: 0197-8462
    Keywords: power substation ; harmonic distortion ; ELF magnetic field ; calculation ; measurement ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: This paper presents a theoretical analysis of electromagnetic environments in power substations in service. A new analytical method is developed and applied to magnetic field calculations in 187-kV and 66-kV substations. Experimental results verify that the method offers a good prediction of the magnetic field profiles in the substations except for the areas where localized field sources exist. The analytical results show that the magnetic field strength depends to a great extent on how the load powers distribute on individual lines and buses, that the magnetic fields in substations have a three-dimensional characteristic, and that the predominant field component depends on the position of interest. Moreover, it is suggested that objects placed in substations are exposed not only to magnetic fields of high strength in comparison to those in houses or near the distribution networks but also to fields with several percent of harmonic distortion.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250100106
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  • 9
    Electronic Resource
    Electronic Resource
    Absorption of microwave radiation by the anesthetized rat: Electromagnetic and thermal hotspots in body and tail (1987)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 8 (1987), S. 385-396 
    Details
    ISSN: 0197-8462
    Keywords: SAR ; blood flow ; temperature ; frequency ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Anatomic variability in the deposition of radiofrequency electromagnetic energy in mammals has been well documented. A recent study [D'Andrea et al., 1985] reported specific absorption rate (SAR) hotspots in the brain, rectum and tail of rat carcasses exposed to 360- and to 2,450-MHz microwave radiation. Regions of intense energy absorption are generally thought to be of little consequence when predicting thermal effects of microwave irradiation because it is presumed that heat transfer via the circulatory system promptly redistributes localized heat to equilibrate tissue temperature within the body. Experiments on anesthetized, male Long-Evans rats (200-260 g) irradiated for 10 or 16 min with 2,450, 700, or 360 MHz radiation at SARs of 2 W/kg, 6 W/kg, or 10 W/ kg indicated that postirradiation localized temperatures in regions previously shown to exhibit high SARs were appreciably above temperatures at body sites with lower SARs. The postirradiation temperatures in the rectum and tail were significantly higher in rats irradiated at 360 MHz and higher in the tail at 2,450 MHz than temperatures resulting from exposure to 700 MHz. This effect was found for whole-body-averaged SARs as low as 6 W/kg at 360 MHz and 10 W/kg at 2,450 MHz. In contrast, brain temperatures in the anesthetized rats were not different from those measured in the rest of the body following microwave exposure.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250080407
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  • 10
    Electronic Resource
    Electronic Resource
    Microwave radiation absorption in the rat: Frequency-dependent SAR distribution in body and tail (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 6 (1985), S. 199-206 
    Details
    ISSN: 0197-8462
    Keywords: microwave ; SAR ; hotspots ; dose distribution ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Experiments were conducted using twin-well calorimetry to determine the averaged whole-body specific absorption rate (SAR) for rat carcasses exposed to 360, 700, 915, and 2,450 MHz CW radiation in an anechoic chamber. All exposures were done with the long axis of the rat in an E-polarization. Additional experiments were conducted using a fiber optical temperature probe to determine local SAR in the brain, esophagus, colon, rectum, and tail during microwave exposure. The whole-body averaged SAR for the radiation frequencies examined follows a nonmonotonic function with 700 MHz as the resonant frequency. This result agrees with previous analytical estimates. Local SARs within the body and tail are nonuniform with significant frequency-specific hotspots in the colon, rectum, and tail.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250060211
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