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  • 1
    Electronic Resource
    Electronic Resource
    Detection thresholds for 60 Hz electric fields by nonhuman primates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 23-34 
    Details
    ISSN: 0197-8462
    Keywords: baboon (Papio cynocephalus) ; method of constant stimuli ; psychophysics ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Because responses of animals to detection of the presence of an electric field (EF) are a possible mechanism for production of biological effects, it is important to know what EF intensities are detectable. Operant methods were used to train six baboons (Papio cyncocephalus) to perform a psychophysical task involving detection of EF presence. During the response phase of a trial, a subject responded on one push button to report the presence of the EF and on a different push button to report the absence of the EF. Correct reports of EF presence or absence produced delivery of food rewards. The subjects became proficient at performing this psychophysical detection task; during 35 days of testing, false alarm rates averaged 9%. The average EF detection threshold was 12 kV/m; the range of means among subjects was 5-15 kV/m. Two special test procedures confirmed that the subjects were responding directly to EF presence or absence and not to artifacts that might be associated with EF generation. The EF detection threshold of nonhuman primates is similar to thresholds reported for rats and humans. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160704
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  • 2
    Electronic Resource
    Electronic Resource
    A 60 Hz electric and magnetic field exposure facility for nonhuman primates: Design and operational data during experiments (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 2-22 
    Details
    ISSN: 0197-8462
    Keywords: baboon (Papio cynocephalus) ; electric field ; exposure ; homogeneity ; magnetic field ; stability ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: A unique exposure facility was designed and constructed to generate large-scale vertical electric fields (EF) of up to 65 kV/m and horizontal magnetic fields (MF) of up to 100μT (1G), so that the behavioral and neuroendocrine effects of 60 Hz EF or combined electric and magnetic field (E/MF) exposure could be examined using nonhuman primates as subjects. Facility design and operational problems and their solutions are presented, and representative operational data from four sets of experiments are provided. A specially designed, optically isolated, 4 cm spherical-dipole EF probe and a commercially available MF probe were used to map the EF and MF within the fiberglass animal cages. In addition, amplifiers, signal conditioners, and A/D converters provided EF, MF, and transformer signals to a microcomputer at 15 min intervals. The apparatus produced homogeneous, stable E/MF at the desired intensities, and the fiberglass cages did not produce appreciable distortion or attenuation. Levels of recognized EF artifacts such as corona and ozone were negligible. The facility worked as intended, providing a well-characterized and artifact-controlled environment for experiments with baboons (Papio cynocephalus). © 1995 Wiley-Liss, Inc.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160703
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  • 3
    Electronic Resource
    Electronic Resource
    Initial exposure to 30 kV/m or 60 kV/m 60 Hz electric fields produces temporary cessation of operant behavior of nonhuman primates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 35-47 
    Details
    ISSN: 0197-8462
    Keywords: baboon ; Papio cynocephalus ; multiple schedule ; FR30 ; DRL20 ; work stoppage ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In two separate experiments, we examined the effects of a 60 Hz electric field (EF) on performance of an operant schedule consisting of two signaled components: fixed-ratio (FR30) and differential reinforcement of low-rate (DRL20). In each experiment, 12 naive baboons (Papio cynocephalus) were assigned randomly to either an EF-exposed experimental group or a sham-exposed control group. A homogeneous vertical EF of 30 kV/m was used in one experiment; 60 kV/m was used in the other. The experimental design for both experiments included 6 week preexposure, exposure, and postexposure periods. The planned analyses indicated no evidence of statistically significant (P 〈.05) effects of EF exposure. However, exploratory analyses comparing performance during the last week of preexposure and the first week of exposure revealed statistically significant acute effects (work stoppage): The mean response rates of the EF-exposed groups were greatly reduced on day 1 of exposure but were normal by the end of day 2 of EF exposure. We hypothesize that introduction of a highly unusual stimulus, the EF, temporarily interfered with normal operant behavior to produce a primary work stoppage. Supplementary cross-over experiments added at the end of each main experiment indicated that work stoppage occurred again when formerly EF-exposed subjects served as sham-exposed controls, while other subjects received their first EF exposure. Presumably, reoccurrence of other stimuli correlated with initial exposure to the EF became sufficient to subsequently cause secondary work stoppage in the absence of direct EF exposure. The primary and secondary work-stoppage effects were reproducible. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160705
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  • 4
    Electronic Resource
    Electronic Resource
    Nonhuman primates will not respond to turn off strong 60 Hz electric fields (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 48-60 
    Details
    ISSN: 0197-8462
    Keywords: aversion ; baboon (Papio cynocephalus) ; operant responding ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Using a set of six baboons (Papio cynocephalus), we conducted a series of seven experiments designed to evaluate the potentially aversive character of a 60 Hz electric field (EF). Initially, the subjects were trained, using food rewards as the reinforcer, to respond only when a cue light was illuminated. Next, an EF was presented along with the cue light; responses produced delivery of a food pellet and turned off both the cue light and the EF. Then, stimulus and reward conditions were varied. We determined that (1) presence of a strong EF does not affect operant responding for food rewards, (2) subjects will not respond at normal rates when the only reinforcer is termination of a strong EF, (3) presence of a strong EF can serve as a discriminative stimulus, (4) presence of a strong EF does not affect extinction of an appetite-motivated task, and (5) presentation of an EF can become a secondary reinforcer. The pattern of results was consistent across all experiments, suggesting that an EF of as much 65 kV/m is not aversive to nonhuman primates. Separately, we demonstrated that the average EF detection threshold for baboons is 12 kV/m. Thus, EF exposure at intensities well above the detection threshold and at species-scaled EF strengths greater than those found environmentally does not appear to be aversive. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160706
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  • 5
    Electronic Resource
    Electronic Resource
    Exposure of baboons to combined 60 Hz electric and magnetic fields does not produce work stoppage or affect operant performance on a match-to-sample task (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 61-70 
    Details
    ISSN: 0197-8462
    Keywords: Papio cynocephalus ; short-term memory ; operant behavior ; learning ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: We examined the effects of combined 60 Hz electric and magnetic field (EMF) exposure on performance of delayed match-to-sample (MTS) procedure involving the flash rate of a light as the stimulus. Six baboons (Papio cynocephalus) fully acquired the task; four others functioned accurately only when cued. All ten subjects were assigned to EMF-exposed or sham-exposed groups of five and were used to test for a work-stoppage effect that was previously observed with initial exposure to electric fields (EF) of 30 or 60 kV/m. Here, we report the results of two experiments, each consisting of 6 week preexposure, exposure, and postexposure periods. We found no evidence of work stoppage with fields of 6 kV/m and 50 μT (0.5 G) or with 30 kV/m and 100 μT (1.0 G). In neither experiment was there evidence of an adverse effect of 60 Hz EMF exposure on MTS performance. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160707
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  • 6
    Electronic Resource
    Electronic Resource
    Initial studies on the effects of combined 60 Hz electric and magnetic field exposure on the immune system of nonhuman primates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 93-102 
    Details
    ISSN: 0197-8462
    Keywords: baboon (Papio cynocephalus) ; interleukin 2 ; mitogen response ; peripheral blood lymphocytes ; T helper/suppressor cell ratio ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In a pilot immunology experiment, peripheral blood samples from six baboons (Papio cynocephalus) housed as a social group were collected during week 5 of preexposure, exposure, and postexposure periods that were each 6 weeks in duration. The subjects were exposed to vertical 6 kV/m and horizontal 50 μT (0.5 G) fields for 12 h per day. Lymphocytes collected during the exposure period displayed statistically significant (P 〈.05) reductions in CD3+ and CD4+ counts, interleukin 2 receptor expression, and proliferative response to pokeweed mitogen. A second experiment was conducted using samples from seven subjects exposed to 30 kV/m and 100 μT (1.0 G) and eight sham-exposed subjects. Statistically significant Period × Group interactions occurred for total white blood cell count and CD4+ to CD8+ ratio, but the pattern of results was not suggestive of an exposure-related effect. Although components of the nonhuman primate immune system appear to be affected by 60 Hz electric and magnetic field exposure in one of two experiments, additional experiments are required to evaluate this possibility. © 1995 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160709
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  • 7
    Electronic Resource
    Electronic Resource
    Rapid-onset/offset, variably scheduled 60 Hz electric and magnetic field exposure reduces nocturnal serum melatonin concentration in nonhuman primates (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 119-122 
    Details
    ISSN: 0197-8462
    Keywords: baboon (Papio cynocephalus) ; intermittent ; irregular ; pineal gland ; transient ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Experiments with rodents indicate that power-frequency electric field (EF) or magnetic field (MF) exposure can suppress the normal nocturnal increase in melatonin concentration in pineal gland and blood. In a separate set of three experiments conducted with nonhuman primates, we did not observe melatonin suppression as a result of 6 weeks of day-time exposure to combined 60 Hz electric and magnetic fields (E/MF) with regularly scheduled “slow” E/MF onsets/offsets. The study described here used a different exposure paradigm in which two baboons were exposed to E/MF with “rapid” E/MF onsets/offsets accompanied by EF transients not found with slowly ramped E/MF onset/offset; profound reductions in nocturnal serum melatonin concentration were observed in this experiment. If replicated in a more extensive experiment, the observation of melatonin suppression only in the presence of E/MF transients would suggest that very specific exposure parameters determine the effects of 60 Hz E/MF on melatonin. © 1995 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160712
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