Abstract:
:Experiments were conducted to see whether the cellular response to electromagnetic (EM) fields occurs through a detection process involving temporal sensing. L929 cells were exposed to 60 Hz magnetic fields and the enhancement of ornithine decarboxylase (ODC) activity was measured to determine cellular response to the field. In one set of experiments, the field was turned alternately off and on at intervals of 0.1 to 50 s. For these experiments, field coherence was maintained by eliminating the insertion of random time intervals upon switching. Intervals < or = 1 s produced no enhancement of ODC activity, but fields switched at intervals > or 10 s showed ODC activities that were enhanced by a factor of approximately 1.7. These data indicate that it is the interval over which field parameters (e.g., amplitude or frequency) remain constant, rather than the interval over which the field is coherent, that is critical to cellular response to an EMF. In a second set of experiments, designed to determine how long it would take for cells to detect a change in field parameters, the field was interrupted for brief intervals (25-200 ms) once each second throughout exposure. In this situation, the extent of EMF-induced ODC activity depended upon the duration of the interruption. Interruptions > or = 100 ms were detected by the cell as shown by elimination of field-induced enhancement of ODC. That two time constants (0.1 and 10 s) are involved in cellular EMF detection is consistent with the temporal sensing process associated with bacterial chemotaxis. By analogy with bacterial temporal sensing, cells would continuously sample and average an EM field over intervals of about 0.1 s (the "averaging" time), storing the averaged value in memory. The cell would compare the stored value with the current average, and respond to the EM field only when field parameters remain constant over intervals of approximately 10 s (the "memory" time).
journal_name
Bioelectromagneticsjournal_title
Bioelectromagneticsauthors
Litovitz TA,Penafiel M,Krause D,Zhang D,Mullins JMdoi
10.1002/(sici)1521-186x(1997)18:5<388::aid-bem6>3.subject
Has Abstractpub_date
1997-01-01 00:00:00pages
388-95issue
5eissn
0197-8462issn
1521-186Xpii
10.1002/(SICI)1521-186X(1997)18:5<388::AID-BEM6>3.journal_volume
18pub_type
杂志文章abstract::The aim of the present study was to determine millimeter wave (MMW) absorption by blood vessels traversing the subcutaneous fat layer of murine skin. Most calculations were performed using the finite-difference time-domain (FDTD) technique. We used two types of models: (1) a rectangular block of multilayer tissue with...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20658
更新日期:2011-09-01 00:00:00
abstract::There is growing public concern that radio frequency electromagnetic fields may have adverse biological effects. In the present study eight healthy male students were tested to see whether or not radio frequency electromagnetic fields as used in modern digital wireless telecommunication (GSM standard) have noticeable ...
journal_title:Bioelectromagnetics
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1002/bem.51
更新日期:2001-05-01 00:00:00
abstract::Several investigators have reported robust, statistically significant results that indicate that weak (approximately 1 microT) magnetic fields (MFs) increase the rate of morphological abnormalities in chick embryos. However, other investigators have reported that weak MFs do not appear to affect embryo morphology at a...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/(sici)1521-186x(1997)18:6<431::aid-bem5>3.
更新日期:1997-01-01 00:00:00
abstract::The effects of hyperthermia, alone and in conjunction with microwave exposure, on brain energetics were studied in anesthetized male Sprague-Dawley rats. The effect of temperature on adenosine triphosphate concentration [ATP] and creatine phosphate concentration [CP] was determined in the brains of rats that were main...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250050107
更新日期:1984-01-01 00:00:00
abstract::We summarize the results of several of our recent studies on the dielectric properties of protein solutions, tissues, and nonionic microemulsions at microwave frequencies extending to 18 GHz. The data in all cases are analyzed using the Maxwell mixture theory to determine the dielectric properties of the suspending wa...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250030108
更新日期:1982-01-01 00:00:00
abstract::An experimental arrangement is described that maximized the dosimetric information that can be obtained during in vitro studies with ELF magnetic fields. The arrangement enables researchers to distinguish between a purely magnetic-field effect and one that also involves the electric fields and currents induced by the ...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250110306
更新日期:1990-01-01 00:00:00
abstract::This study reports the continuous 8-h monitoring of data on extremely low-frequency magnetic fields (ELF-MF) relating to 14 children and 35 teachers in 11 elementary schools in Northern Taiwan. It was anticipated that the subjects in two of these campuses would have elevated exposure to ELF-MF as a result of their clo...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20431
更新日期:2008-10-01 00:00:00
abstract::Findings from prior studies of possible health and physiological effects from mobile phone use have been inconsistent. Exposure periods in provocation studies have been rather short and personal characteristics of the participants poorly defined. We studied the effect of radiofrequency field (RF) on self-reported symp...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20379
更新日期:2008-04-01 00:00:00
abstract::The influence of a pulsed magnetic field (PMF; sawtooth with 45-microseconds linear rise time and 5-microseconds decay time, peak strength of 15 microT, and frequency 20000 pps) [corrected] on the embryogenesis of CBA/S mice was investigated in five experiments based on a total of 707 exposed and 543 unexposed primigr...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250140303
更新日期:1993-01-01 00:00:00
abstract::It has been suggested that exposure to electromagnetic fields may be a risk factor for cardiovascular disease in humans. Low density lipoprotein (LDL) modifications such as peroxidation and aggregation have been implicated in the pathogenesis of atherosclerosis. The present study investigated the effects of weak (0.12...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.21779
更新日期:2013-07-01 00:00:00
abstract::To characterize the inhibitory effect of a static magnetic field, action potentials (AP) were elicited by intracellular application of 1 ms depolarizing current pulses of constant amplitude to the somata of adult mouse dorsal root ganglion neurons in monolayer dissociated cell culture. During the control period, < 5% ...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250160108
更新日期:1995-01-01 00:00:00
abstract::Cell-based or magnetic field therapies as alternative approaches to pain management have been tested in several experimental pain models. The aim of this study therefore was to investigate the actions of the cell-based therapy (adipose tissue derived mesenchymal stem cells; ADMSC) or pulsed magnetic field (PMF) therap...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.22038
更新日期:2017-05-01 00:00:00
abstract::We developed a new computer wire coding method and then applied it to investigate the suggestion that control selection bias might explain the observed association between wire codes and childhood cancer made in the study conducted by Savitz et al. in the Denver area. The computer wire coding method used a geographic ...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:
更新日期:2000-07-01 00:00:00
abstract::Conductive nanoparticles may enhance tissue heating during radiofrequency (RF) irradiation. Specific absorption rate (SAR) is known to rise with the electrical conductivity of tissue. However, no studies to date have measured the relationship between complex permittivity and nanoparticle concentration in tissue-like s...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20595
更新日期:2010-12-01 00:00:00
abstract::Calcium (45Ca2+) efflux from preloaded synaptosomes was studied with a continuous perfusion technique and the rate constants of a two-phase efflux process calculated. When 16-Hz sinusoidally amplitude modulated 450-MHz microwave field (maximal incident intensity 0.5 mW/cm2, modulation depth 75%) was applied during the...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250030303
更新日期:1982-01-01 00:00:00
abstract::This study was designed to determine the changes that occur in the thermoregulatory ability of the immature rat repeatedly exposed to low-level microwave radiation. Beginning at 6-7 days of age, previously untreated rats were exposed to 2,450-MHz continuous-wave microwaves at a power density of 5 mW/cm2 for 10 days (4...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250080307
更新日期:1987-01-01 00:00:00
abstract::The effects of an extremely low frequency (ELF) magnetic field on the sex hormones and other fertility parameters of adult male Sprague-Dawley rats were investigated. Adult male rats were exposed to a 50 Hz sinusoidal magnetic field at approximately 25 microT (rms) for 18 consecutive weeks. There were no significant e...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20186
更新日期:2006-02-01 00:00:00
abstract::The hypogeomagnetic field (HGMF; magnetic fields <200 nT) is one of the fundamental environmental factors of space. However, the effect of HGMF exposure on living systems remains unclear. In this article, we examine the biological effects of HGMF on the embryonic development of Xenopus laevis (African clawed frog). A ...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20699
更新日期:2012-04-01 00:00:00
abstract::In order to demonstrate possible specific effects of microwaves at the cellular level V-79 Chinese hamster cells were exposed to 2.45-GHz radiation at power levels of 20-200 mW/cm2 and at specific absorption rates of 10-100 mW/g. Intracellular cytoplasmic changes were observed by fluorescence polarization using a meth...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250050212
更新日期:1984-01-01 00:00:00
abstract::In this work we tested viability, proliferation, and vulnerability of neural cells, after continuous radiofrequency (RF) electromagnetic fields exposure (global system for mobile telecommunications (GSM) modulated 900 MHz signal at a specific absorption rate (SAR) of 1 W/kg and maximum duration 144 h) generated by tra...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20507
更新日期:2009-10-01 00:00:00
abstract::Both eyes of anesthetized cynomolgus monkeys (Macaca fascicularis) were irradiated with 2.45-GHz microwaves, either pulsed or continuous wave. In vivo corneal endothelial abnormalities were observed by specular microscopy and confirmed through histologic techniques after a 16- to 48-hour postexposure period. Pulsed mi...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.2250060209
更新日期:1985-01-01 00:00:00
abstract::We exposed normal human epidermal keratinocytes to short duration, high frequency, and low amplitude electromagnetic fields, similar to that used by mobile phone technologies. We paid particular attention to the control of the characteristics of the electromagnetic environment generated within a mode stirred reverbera...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20641
更新日期:2011-05-01 00:00:00
abstract::The goal of the research reported here is to narrow the range of uncertainty about peripheral nerve stimulation (PNS) thresholds associated with whole body magnetic field exposures at 50/60 Hz. This involved combining PNS thresholds measured in human subjects exposed to pulsed magnetic gradient fields with calculation...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20106
更新日期:2005-09-01 00:00:00
abstract::Effects of short, extremely high power microwave pulses (EHPP) on neuronal network function were explored by electrophysiological techniques in the isolated rat hippocampal slice model. Population spikes (PS) in the CA1 area were evoked by repeated stimulation (1 per 30 s) of the Schaffer collateral pathway. A brief t...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.10079
更新日期:2003-04-01 00:00:00
abstract::Extremely low-frequency (ELF) magnetic field exposure systems are usually subject to field disturbances induced by external sources. Here, a method for designing a feedback control system for cancelling the effect of external ELF magnetic field disturbances on the magnetic field over the exposure area is presented. Th...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/(sici)1521-186x(1997)18:4<299::aid-bem2>3.
更新日期:1997-01-01 00:00:00
abstract::Since 1994, our research has demonstrated how thermophysiological responses are mobilized in human volunteers exposed to three radio frequencies, 100, 450, and 2450 MHz. A significant gap in this frequency range is now filled by the present study, conducted at 220 MHz. Thermoregulatory responses of heat loss and heat ...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20105
更新日期:2005-09-01 00:00:00
abstract::The impedance spectroscopy technique (IST) was used for studying the effect of a 0.5 T magnetic field on the electrical properties of whole human blood. A Solartron SI 1260 spectrometer was used to measure the impedance spectra of magnetic field exposed blood samples compared to non-exposed samples. An equivalent elec...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/bem.20132
更新日期:2005-10-01 00:00:00
abstract::Blackman et al. [1994] describe an experiment that purports to show that weak 45 Hz magnetic fields inhibit the growth of neurites from PC-12 cells treated with a growth stimulation factor. I present a statistical analysis of the data in that paper that shows that the data were corrupted in some way; hence, the result...
journal_title:Bioelectromagnetics
pub_type: 评论,杂志文章
doi:10.1002/(SICI)1521-186X(1996)17:6<510::AID-BEM12>3
更新日期:1996-01-01 00:00:00
abstract::In epidemiological studies of electromagnetic fields and health effects, exposure classification is crucial. There is no generally accepted biophysical interaction mechanism, but many studies are based on the hypothesis of a causal relationship with the strength of magnetic field. Some definition of the magnitude of e...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:10.1002/(SICI)1521-186X(1996)17:3<209::AID-BEM6>3.
更新日期:1996-01-01 00:00:00
abstract::The accurate and valid measurement of personal exposure to magnetic fields poses a major challenge for epidemiologic studies. When considering the various methods to assess exposure, it is unclear which measures are most relevant for studies of human disease, if any. Given these uncertainties, the Electromagnetic Fiel...
journal_title:Bioelectromagnetics
pub_type: 杂志文章
doi:
更新日期:1999-12-01 00:00:00