摘要:

AbstractIn a case‐control study of adult acute and chronic myelogenous leukemia in Los Angeles County, we tested the hypothesis that excess exposure to electromagnetic fields from electric blankets was associated with risk of leukemia. We did this by studying 116 cases of acute myelogenous leukemia (AML) and 108 cases of chronic myelogenous leukemia (CML) along with matched neighborhood controls. The cases and controls were queried as to electric blanket use and the risks computed. For AML the risk was 0.9 (95% CI 0.5–1.6) and for CML the risk was 0.8 (95% CI 0.4–1.6). Cases did not differ from controls by duration of use, year of first regular use, year since last use, or socioeconomic status. Our best estimates of exposure indicate that electric blanket use increases overall exposure to electric fields by less than 50% and magnetic fields by less than 100%. We conclude that there is no major leukemogenic risk associated with electric blanket use in Los Angeles C

ISSN:0197-8462    

DOI:10.1002/bem.2250090302

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThe frequency dependence of electromagnetic field‐induced calcium‐ion efflux from chicken brain tissues has been examined at 15‐Hz intervals over the range 1–510 Hz. The electric field component was 15 Vrms/m and the magnetic component varied between 59 and 69 nTrms. No patterns of response as a function of frequency could be readily discerned when the differences in mean efflux values between exposed and sham samples were compared. However, the calculated P‐value, a function that combines at each frequency the difference between the means of the exposed and sham groups with the variance of each group, does provide a basis for hypothesizing the existence of three frequency‐dependent patterns in the data. One pattern includes all the highly significant (P.5), break this pattern into two groups of five frequencies each, which is contrary to the expected result for a simple Lorentz‐force interaction. However, another pattern of significant results at 60, 90, and 180 Hz, but not at 300 Hz, is consistent with a Lorentz‐force model. A third pattern, composed of only one significant response at 405 Hz, is very close to the resonance predicted on a linear extrapolation from high‐frequency data for13carbon atoms. This hypothetical ordering of the frequency‐response profile provides the basis for future experimental designs to test each possible interaction model and for their connection to the calciu

ISSN:0197-8462    

DOI:10.1002/bem.2250090303

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractLevels of brain neurotransmitters and their metabolites, as well as concentrations of enzymes associated with their synthesis and metabolism, fluctuate during the day in patterns defined as circadian. The present study examined these rhythms in albino rats exposed to 60‐Hz electric fields. Thirty‐six animals were exposed to a 39 kV/m field for 4 weeks, 20 h/day, in a parallel‐plate electrode system. A group of 36 sham animals was similarly handled and housed in a nonenergized exposure system. On the sampling day, animals were sacrificed at 4‐h intervals throughout the 24‐h day. Brains were removed, dissected, and kept frozen until chemically analyzed. The levels of biogenic amines and their acidic metabolites in the striatum, hypothalamus, and hippocampus were determined by high‐performance liquid chromatography with electrochemical detection (HPLC‐ECD) methods. Repeated exposure to 60‐Hz electric fields produced significant alterations in the diurnal rhythms of several biogenic amines: dihydroxyphenylacetic acid (DOPAC, the primary metabolite of dopamine in the rat) in the striatum, and norepinephrine, dopamine, and 5‐hydroxyindoleacetic acid (5‐HIAA; serotonin metabolite) in the hypothalamus. Levels of serotonin in the striatum and hypothalamus showed clear circadian patterns that was not affected by the field. No diurnal or field‐related changes were observed in t

ISSN:0197-8462    

DOI:10.1002/bem.2250090304

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractChinese hamster ovary (CHO) cells were exposed for 1 h to 60‐Hz magnetic fields (0.1 or 2 mT), electric fields (1 or 38 V/m), or to combined magnetic and electric fields (2 mT and 38 V/m, respectively). Following exposure, the cells were lysed, and the DNA was analyzed for the presence of single‐strand breaks (SSB), using the alkaline elution technique. No significant differences in numbers of DNA SSB were detected between exposed and sham‐exposed cells. A positive control exposed to X‐irradiation sustained SSB with a dose‐related frequency. Cells exposed to nitrogen mustard (a known cross‐linking agent) and X‐irradiation demonstrated that the assay could detect cross‐linked DNA under our conditions of electric and magnetic

ISSN:0197-8462    

DOI:10.1002/bem.2250090305

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractLarge unilamellar dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphos‐phatidylglycerol (DPPG) liposomes loaded with an aqueous chemotherapeutic drug, cytosine arabinofuranoside (ARA‐C), were exposed for 30 min to 60 W/kg continuous‐wave (CW) 100‐MHz or 2.45‐GHz radiation in vitro at temperatures between 37 °C and 43 °C. Liposomes were exposed in HEPES buffer or in HEPES buffer supplemented with 44% by volume fetal calf serum (FCS). Characteristic phase transition responses were detected in the range of 39 °C to 40 °C with the presence of FCS, increasing maximum % release of3H‐ARA‐C by 20% relative to HEPES suspension. Neither frequency of electromagnetic radiation had any detectable effect on liposome permeability or the location of the phase transition in the presence

ISSN:0197-8462    

DOI:10.1002/bem.2250090306

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractRats were tested for neurobehavioral alterations immediately after exposure to 2.45‐GHz (CW) microwave radiation at 10 mW/cm2for 7 h. Behavioral tests used were locomotor activity, startle to an acoustic stimulus and acquisition and retention of a shock‐motivated passive avoidance task. Both horizontal and vertical components of locomotor activity were assessed in 5‐min epochs for a period of 30 min using photoelectric detectors. Microwave‐exposed animals exhibited less activity than sham‐exposed animals. This was most evident during the last 10–15 min of the 30‐min test session. Twenty identical acoustical stimuli (8 KHz, 110 dB) were delivered to each rat at 40‐s intervals. The microwave‐exposed animals were less responsive to the stimuli than sham‐exposed animals. Microwave exposure had no effect on the retention of a passive avoidance procedure when tested at 1 week after training. Both the locomotor activity and acoustic startle data demonstrate that, under the conditions of this experiment, microwave exposure may alter responsiveness of rats to novel environmental co

ISSN:0197-8462    

DOI:10.1002/bem.2250090307

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractInfant albino rats were exposed to a static electromagnetic field of 0.0 Tesla (control) or 0.5 Tesla (experimental) for 14 postnatal days. Following a 1‐month rest period, the experimental (13 males and 10 females) and control (11 males and 14 females) rats were trained on four successive reversals of a position habit in a single‐unit enclosed T‐maze that was adapted for the use of escape‐avoidance of mild foot shock as a motive. There was no significant difference in learning ability between the experimental and control groups in terms of total (initial combined with repetitive) errors committed over the four reversal problems. While the females tended to make more errors than the males, this difference was likewise insign

ISSN:0197-8462    

DOI:10.1002/bem.2250090308

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractMechanisms to explain disturbance of honey bee colonies under a 765‐kV, 60‐Hz transmission line [electric (E) field = 7 kV/m] fall into two categories: direct bee perception of enhanced in‐hive E fields, and perception of shock from induced currents. The same adverse biological effects previously observed in honey bee colonies exposed under a 765‐kV transmission line can be reproduced by exposing worker bees to shock or E field within elongated hive entranceways (=tunnels). Exposure to intense E field caused disturbance only if bees were in contact with a conductive substrate. E‐field and shock exposure can be separated and precisely defined within tunnels, eliminating dosimetric vagaries that occur when entire hives are exposed t

ISSN:0197-8462    

DOI:10.1002/bem.2250090309

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractThis work explores mechanisms for disturbance of honey bee colonies under a 765 kV, 60‐Hz transmission line [electric (E) field = 7 kV/m] observed in previous studies. Proposed mechanisms fell into two categories: direct bee perception of enhanced in‐hive E fields and perception of shock from induced currents. The adverse biological effects could be reproduced in simulations where only the worker bees were exposed to shock or to E field in elongated hive entranceways (=tunnels). We now report the results of full‐scale experiments using the tunnel exposure scheme, which assesses the contribution of shock and intense E field to colony disturbance.Exposure of worker bees (1,400 h) to 60‐Hz E fields including 100 kV/m under moisture‐free conditions within a nonconductive tunnel causes no deleterious affect on colony behavior. Exposure of bees in conductive (e.g., wet) tunnels produces bee disturbance, increased mortality, abnormal propolization, and possible impairment of colony growth. We propose that this substrate dependence of bee disturbance is the result of perception of shock from coupled body currents and enhanced current densities postulated to exist in the legs and thorax of bees on conductors. Similarly, disturbance occurs when bees are exposed to step‐potential‐induced currents. At 275–350 nA single bees are disturbed; at 600 nA bees begin abnormal propolization behavior; and stinging occurs at 900 nA.We conclude that biological effects seen in bee colonies under a transmission line are primarily the result of electric shock from induced hive currents. This evaluation is based on the limited effects of E‐field exposure in tunnels, the observed disturbance thresholds caused by shocks in tunnels, and the ability of hives exposed under a transmission line to source currents 100–1,000 times t

ISSN:0197-8462    

DOI:10.1002/bem.2250090310

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY

摘要:

AbstractA significant 25% inhibition (P<.005) of allogeneic cytotoxicity of the target cell MPC‐11 by the murine cytotoxic T‐lymphocyte line CTLL‐1 was observed when the 4‐h cytotoxicity assay was conducted immediately following a 48‐h pre‐exposure of the effector lymphocytes to a 10‐mV/cm (rms) 60‐Hz sinusoidal electric field. At 1.0 mV/cm a significant 19% inhibition (P<.0005) was seen. At 0.1 mV/cm a nonsignificant 7% inhibition of cytotoxicity was noted. When the 4‐h cytotoxicity assay was conducted in the presence of the field using previously unexposed effector lymphocytes, cytotoxicity was not significantly reduced. Cell proliferation in the presence of interleukin‐2 was unaffected by the field. These data suggest a dose response and threshold (between 0.1 and 1.0 mV/cm) for inhibition of cytotoxicity in clonal T‐lymphocytes by exposure to a 60‐Hz sinusoidal electric field. These results suggest mechanisms by which 60‐Hz electric fields could affect the function of c

ISSN:0197-8462    

DOI:10.1002/bem.2250090311

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1988

数据来源: WILEY