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  • The Lack of Toxic Effect of High‐Power Short‐Pulse 101 GHz Millimeter Waves on Healthy Mice
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-17
    Olga Furman; Konstantin Komoshvili; Jakob Levitan; Asher Yahalom; Harry Marks; Dmitri Borodin; Stella Liberman‐Aronov

    Irradiation of cancer cells by non‐ionizing millimeter waves (MMW) causes increased cell mortality. We examined if MMW have toxic effects on healthy mice. To that end, the skin of healthy C57BL/6 mice was irradiated locally at the right flank with 101 GHz MMW in a pulsed (5–10 µs) regime using a free electron laser. Irradiation was performed in a dose‐dependent manner, with 20–50 pulses and a power range of 0.5–1.5 kW. Physical, physiological, and pathological parameters as well as behavior were examined before and after irradiation. Our results showed that all parameters were within normal range for all experimental mice groups and for the control group. No significant changes were noted in the physical, physiological, or behavioral status of the mice following irradiation as compared with the control group. In addition, no significant changes were found in locomotor, exploratory behavior, or anxiety of the irradiated mice and no pathological changes were noted following the hematological and biochemical blood analysis. Our results indicate that irradiation of healthy mice with MMW does not cause any general toxic effects. Bioelectromagnetics. © 2020 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • The Relative Permittivity Changes of EGF by 50 Hz MF Exposure Neither Affect the Interaction of EGF With EGFR Nor Its Biological Effects
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-17
    Yue Fei; Yumin Jin; Xinyuan Zhao; Yiqin Wang; Jun Qian; Liling Su; Guangdi Chen

    The biophysical mechanism of magnetic fields (MFs) acting on living systems is not clear. Previous research showed that, similar to epidermal growth factor (EGF), MF exposure induced EGF receptor (EGFR) clustering and activated EGFR signaling. In this study, we investigated whether MF exposure induced the changes in physical characteristics of EGF and downstream effects of EGF and EGFR interaction. The phase‐interrogation surface plasmon resonance (SPR) sensing analyses showed that 50 Hz MF exposure at 4.0 mT for 1 h induced reversible relative permittivity changes of EGF solution. However, compared with sham‐exposed EGF solution, the MF‐exposed EGF solution did not affect the binding of EGF to EGFR, nor the cell viability and EGFR clustering in human amniotic epithelial cells (FL cells). Our data suggest that cellular EGFR clustering response to MF exposure might not be a result of changes in relative permittivity of EGF in cell culture solution. Bioelectromagnetics. © 2020 Bioelectromagnetics Society

    更新日期:2020-01-17
  • Effect of Pulsed Electromagnetic Fields on Human Mesenchymal Stem Cells Using 3D Magnetic Scaffolds
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-15
    Alyaa I. Aldebs; Fatema T. Zohora; Nasim Nosoudi; Surinder P. Singh; Jaime E. Ramirez‐Vick

    Alternative bone regeneration strategies that do not rely on harvested tissue or exogenous growth factors are needed. One of the major challenges in tissue reconstruction is recreating the bone tissue microenvironment using the appropriate combination of cells, scaffold, and stimulation to direct differentiation. This study presents a bone regeneration formulation that involves the use of human adipose‐derived mesenchymal stem cells (hASCs) and a three‐dimensional (3D) hydrogel scaffold based on self‐assembled RADA16 peptides containing superparamagnetic iron oxide nanoparticles (NPs). Although superparamagnetic NPs could be used as stimulus to manipulate the cell proliferation and differentiation, in this paper their use is explored for assisting osteogenic differentiation of hASCs in conjunction with direct stimulation by extremely low‐frequency pulsed electromagnetic fields (pEMFs). Cellular morphology, proliferation, and viability, as well as alkaline phosphatase activity, calcium deposition, and osteogenic capacity were monitored for cells cultured up to 21 days in the 3D construct. The results show that the pEMFs and NPs do not have any negative effect on cell viability, but instead distinctly induced early differentiation of hASCs to an osteoblastic phenotype, when compared with cells without biophysical stimulation. This effect is attributed to synergy between the pEMFs and NPs, which may have stimulated mechanotransduction pathways, which, in turn activated biochemical signals between cells to differentiate or proliferate. This approach may offer a safe and effective option for the treatment of non‐union bone fractures. Bioelectromagnetics. © 2020 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc.

    更新日期:2020-01-17
  • An Extremely Low Frequency Magnetic Field and Global Cerebral Ischemia Affect Pituitary ACTH and TSH Cells in Gerbils
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-11
    Snežana Rauš Balind; Milica Manojlović‐Stojanoski; Branka Šošić‐Jurjević; Vesna Selaković; Verica Milošević; Branka Petković

    The neuroendocrine system can be modulated by a magnetic field and cerebral ischemia as external and internal stressors, respectively. This study deals with the separate or combined effects of an extremely low frequency (ELF) magnetic field (50 Hz, average magnetic field of 0.5 mT) for 7 days and global cerebral ischemia for 10 min on the morpho‐functional features of pituitary adrenocorticotrophic (ACTH) and thyrotrophic (TSH) cells in 3‐month‐old gerbils. To determine the immediate and delayed effects of the applied stressors, measurements were made on the 7th and 14th days after the onset of the experiment. The ELF magnetic field and 10‐min global cerebral ischemia, separately and particularly in combination, decreased (P < 0.05) the volume density of ACTH cells, while only in combination were intracellular ACTH content and plasma ACTH concentration increased (P < 0.05) on day 7. The ELF magnetic field elevated serum TSH concentration on day 7 and intracellular TSHβ content on day 14 (P < 0.05). Also, 10‐min global cerebral ischemia alone increased serum TSH concentration (P < 0.05), while in combination with the ELF magnetic field it elevated (P < 0.05) intracellular TSHβ content on day 14. In conclusion, an ELF magnetic field and/or 10‐min global cerebral ischemia can induce immediate and delayed stimulation of ACTH and TSH synthesis and secretion. Bioelectromagnetics. 2020;41:91–103. © 2019 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Effect of Exposure to a Radiofrequency Electromagnetic Field on Body Temperature in Anesthetized and Non‐Anesthetized Rats
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-11
    Hye Sun Kim; Yu Hee Lee; Hyung‐Do Choi; Ae‐Kyoung Lee; Sang Bong Jeon; Jeong‐Ki Pack; Nam Kim; Young Hwan Ahn

    Exposure to a radiofrequency (RF) signal at a specific absorption rate (SAR) of 4 W/kg can increase the body temperature by more than 1 °C. In this study, we investigated the effect of anesthesia on the body temperature of rats after exposure to an RF electromagnetic field at 4 W/kg SAR. We also evaluated the influence of body mass on rats’ body temperature. Rats weighing 225 and 339 g were divided into sham‐ and RF‐exposure groups. Each of the resulting four groups was subdivided into anesthetized and non‐anesthetized groups. The free‐moving rats in the four RF‐exposure groups were subjected to a 915 MHz RF identification signal at 4 W/kg whole‐body SAR for 8 h. The rectal temperature was measured at 1‐h intervals during RF exposure using a small‐animal temperature probe. The body temperatures of non‐anesthetized, mobile 225 and 339 g rats were not significantly affected by exposure to an RF signal. However, the body temperatures of anesthetized 225 and 339 g rats increased by 1.9 °C and 3.3 °C from baseline at 5 and 6 h of RF exposure, respectively. Three of the five 339 g anesthetized and exposed rats died after 6 h of RF exposure. Thus, anesthesia and body mass influenced RF exposure‐induced changes in the body temperature of rats. Bioelectromagnetics. 2020;41:104–112. © 2019 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Ultrasound‐Assisted Enzyme‐Catalyzed Hydrolysis of Collagen to Produce Peptides With Biomedical Potential: Collagenase From Aspergillus terreus UCP1276
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-24
    Romualdo B. Costa‐Junior; Romero M. P. Brandão‐Costa; Wendell W. C. Albuquerque; Juanize M. S. Batista; Raquel B. Pedrosa; Ana L. F. Porto

    Ultrasound has been applied for varied purposes as it provides additional mechanical energy to a system, and is still profitable and straightforward, which are advantages for industrial applications. In this work, ultrasonic treatments were applied to purified collagenase fractions from a fermented extract by Aspergillus terreus UCP 1276 aiming to evaluate the potential effect on collagen hydrolysis. The physical agent was evaluated as an inductor of collagen degradation and consequently as a producer of peptides with anticoagulant activity. The sodium dodecyl sulphate‐polyacrylamide gel electrophoresis analyses were also carried out to compare the hydrolysis techniques. The ultrasound (40 kHz, 47.4 W/L) processing was conducted under the same conditions of pH and temperature at different times. The ultrasound‐assisted reaction was accelerated in relation to conventional processing. Collagenolytic activity was enhanced and tested in the presence of phenylmethanesulfonyl fluoride inhibitor. Underexposure, the activity was enhanced, reaching more than 72.0% of improvement in relation to the non‐exposed enzyme. A period of 30 min of incubation under ultrasound exposure was enough to efficiently produce peptides with biological activity, including anticoagulation and effect on prothrombin time at about 60%. The results indicate that low‐frequency ultrasound is an enzymatic inducer with likely commercial applicability accelerating the enzymatic reaction. Bioelectromagnetics. 2020;41:113–120. © 2019 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Exposure Assessment in Millimeter‐Wave Reverberation Chamber Using Murine Phantoms
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-13
    Abdou Khadir Fall; Christophe Lemoine; Philippe Besnier; Ronan Sauleau; Yves Le Dréan; Maxim Zhadobov

    This study deals with the design and calibration of the first mode‐stirred reverberation chamber (RC) in the 60‐GHz‐band adapted for in vivo bioelectromagnetic studies. In addition to the interface for electromagnetic and thermal dosimetry, the interfaces for lighting and ventilation were integrated into the RC walls while preserving acceptable shielding. The RC with mechanical and electronic steering capabilities is characterized in the 55–65 GHz range. To this end, murine skin‐equivalent phantoms of realistic shape were designed and fabricated. Their complex permittivity is within ±12% of the target value of murine skin (6.19–j5.81 at 60 GHz). The quality factor of the RC loaded with an animal cage, bedding litter, and five murine phantoms was found to be 1.2 × 104. The losses inside the RC were analyzed, and it was demonstrated that the main sources of the power dissipation were the phantoms and mice cage. The input power required to reach the average incident power density of 1 and 5 mW/cm2 was found to be 0.23 and 1.14 W, respectively. Surface heating of the mice models was measured in the infrared (IR) range using a specifically designed interface, transparent at IR and opaque at millimeter waves (mmW). Experimental results were compared with an analytical solution of the heat transfer equation and to full‐wave computations. Analytical and numerical results were in very good agreement with measurements (the relative deviation after 90 min of exposure was within 4.2%). Finally, a parametric study was performed to assess the impact of the thermophysical parameters on the resulting heating. Bioelectromagnetics. 2020;41:121–135. © 2020 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Phantom Model Testing of Active Implantable Cardiac Devices at 50/60 Hz Electric Field
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-05
    Cihan Gerçek; Djilali Kourtiche; Mustapha Nadi; Isabelle Magne; Pierre Schmitt; Patrice Roth; Martine Souques

    Exposure to external extremely low‐frequency (ELF) electric and magnetic fields induces the development of electric fields inside the human body, with their nature depending on multiple factors including the human body characteristics and frequency, amplitude, and wave shape of the field. The objective of this study was to determine whether active implanted cardiac devices may be perturbed by a 50 or 60 Hz electric field and at which level. A numerical method was used to design the experimental setup. Several configurations including disadvantageous scenarios, 11 implantable cardioverter‐defibrillators, and 43 cardiac pacemakers were tested in vitro by an experimental bench test up to 100 kV/m at 50 Hz and 83 kV/m at 60 Hz. No failure was observed for ICNIRP public exposure levels for most configurations (in more than 99% of the clinical cases), except for six pacemakers tested in unipolar mode with maximum sensitivity and atrial sensing. The implants configured with a nominal sensitivity in the bipolar mode were found to be resistant to electric fields exceeding the low action levels, even for the highest action levels, as defined by the Directive 2013/35/EU. Bioelectromagnetics. 2020;41:136–147. © 2020 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Dielectric Properties of Normal and Metastatic Lymph Nodes Ex Vivo From Lung Cancer Surgeries
    Bioelectromagnetics (IF 1.945) Pub Date : 2020-01-08
    Xuefei Yu; Ying Sun; Kaican Cai; Hongfeng Yu; Difu Zhou; Di Lu; Sherman Xuegang Xin

    The dielectric properties of normal and tumor human tissues have been widely reported in recent years. However, the dielectric properties of intrathoracic lymph nodes (LNs) have not been reported. In this communication, we measured the dielectric properties (i.e., permittivity and conductivity) of ex vivo intrathoracic LNs obtained from lung cancer surgeries. Results show that the permittivity and conductivity of metastatic LNs are higher than those of normal LNs over the frequency range of 1 MHz–4 GHz. Statistically significant differences are observed at single specific frequencies (64, 128, 298, 433, and 915 MHz and 2.45 GHz). Our study provides the basic data to support future‐related research and fills the research gap on the dielectric properties of LNs in the lungs. Bioelectromagnetics. 2020;41:148–155. © 2020 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Gender and Age Differences in the Suppressive Effect of a 50 Hz Electric Field on the Immobilization‐Induced Increase of Plasma Glucocorticoid in Mice
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-12
    Shinji Harakawa; Takuya Hori; Takaki Nedachi; Hiroshi Suzuki

    We developed an experimental system to characterize the suppressive effect of extremely low‐frequency (ELF) electric fields (EFs) on the stress response. We assessed differences in the EF effects by age and gender. Control, EF‐alone, immobilization‐alone, and co‐treated groups were subjected to an EF (50 Hz, 10 kV/m). Co‐treated mice were exposed to the EF for 60 min, with immobilization during the latter half. Our results indicate that the suppressive effects of ELF EFs on the stress response in immobilized mice occur regardless of gender or age. As stress plays an important role in the onset and progression of various diseases, these findings may have broad implications for understanding the efficacy of EFs in animal, and perhaps human, health. Bioelectromagnetics. 2020;41:156–163. © 2019 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Discussion on Spatial and Time Averaging Restrictions Within the Electromagnetic Exposure Safety Framework in the Frequency Range Above 6 GHz for Pulsed and Localized Exposures
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-30
    Esra Neufeld; Theodoros Samaras; Niels Kuster

    Both the current and newly proposed safety guidelines for local human exposure to millimeter‐wave frequencies aim at restricting the maximum local temperature increase in the skin to prevent tissue damage. In this study, we show that the application of the current and proposed limits for pulsed fields can lead to a temperature increase of 10°C for short pulses and frequencies between 6 and 30 GHz. We also show that the proposed averaging area of 4 cm2, that is greatly reduced compared with the current limits, does not prevent high‐temperature increases in the case of narrow beams. A realistic Gaussian beam profile with a 1 mm radius can result in a temperature increase about 10 times higher than the 0.4°C increase the same averaged power density would produce for a plane wave. In the case of pulsed narrow beams, the values for the time and spatial‐averaged power density allowed by the proposed new guidelines could result in extreme temperature increases. Bioelectromagnetics. 2020;41:164–168. © 2019 Bioelectromagnetics Society.

    更新日期:2020-01-17
  • Wireless Wearables and Implants: A Dosimetry Review
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-18
    Katrina Guido; Asimina Kiourti

    Wireless wearable and implantable devices are continuing to grow in popularity, and as this growth occurs, so too does the need to consider the safety of such devices. Wearable and implantable devices require the transmitting and receiving of electromagnetic waves near and through the body, which at high enough exposure levels may damage proximate tissues. The specific absorption rate (SAR) is the quantity commonly used to enumerate exposure levels, and various national and international organizations have defined regulations limiting exposure to ensure safe operation. In this paper, we comprehensively review dosimetric studies reported in the literature up to the year 2019 for wearables and implants. We discuss antenna designs for wearables and implants as they relate to SAR values and field and thermal distributions in tissue, present designs that have made steps to reduce SAR, and then review SAR considerations as they relate to applied devices. As compared with previous review papers, this paper is the first review to focus on dosimetry aspects relative to wearable and implantable devices. Bioelectromagnetics. 2020;41:3–20 © 2019 The Authors. Bioelectromagnetics published by Wiley Periodicals, Inc.

    更新日期:2019-12-20
  • Multifrequency Analysis of Single Inductive Coil Measurements Across a Gel Phantom Simulation of Internal Bleeding in the Brain
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-11-21
    Moshe Oziel; Mohammad Hjouj; Boris Rubinsky; Rafi Korenstein

    The present study is part of an ongoing effort to develop a simple diagnostic technology for detecting internal bleeding in the brain, which can be used in lieu or in support of medical imaging and thereby reduce the cost of diagnostics in general, and in particular, would make diagnostics accessible to economically disadvantaged populations. The study deals with a single coil inductive device to be used for detecting cerebral hemorrhage. It presents a first‐order experimental study that examines the predictions of our recently published theoretical study. The experimental model employs a homogeneous cylindrical phantom in which internal head bleeding was simulated by way of a fluid inclusion. We measured the changes in amplitude and phase across the coil with a network vector analyzer as a function of frequency (100–1,000 MHz), volume of blood simulating fluid, and the site of the fluid injection. We have developed a new mathematical model to statistically analyze the complex data produced in this experiment. We determined that the resolution for the fluid volume increase following fluid injection is strongly dependent on frequency as well as the location of liquid accumulation. The experimental data obtained in this study supports the predictions of our previous theoretical study, and the statistical analysis shows that the simple single coil device is sensitive enough to detect changes due to fluid volume alteration of two milliliters. Bioelectromagnetics. 2020;41:21–33 © 2019 Bioelectromagnetics Society

    更新日期:2019-12-20
  • Registry of Buildings With Transformer Stations as a Basis for Epidemiological Studies on Health Effects of Extremely Low‐Frequency Magnetic Fields
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-11-19
    Muhammad Waseem Khan; Jukka Juutilainen; Päivi Roivainen

    Buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the health effects of extremely low‐frequency magnetic fields (ELF MFs). Previous studies have shown that ELF MF exposure can be adequately assessed based on the fact that MF levels are high in apartments directly above transformers. In this paper, we describe the creation of a registry of Finnish residential buildings with built‐in transformer stations and discuss its usability in epidemiological studies. Information obtained from electric utilities and building blueprints were used to identify 677 buildings in which an apartment was located above or adjacent to a transformer station. All apartments in these buildings were classified into exposure categories based on their location in relation to the transformer. Residential histories of these buildings were obtained from the Population Register Centre. Out of the 287,668 individuals who have resided in the buildings, 9,126 of them have resided in an apartment located directly above a transformer station. All information was collected without contacting residents, thus avoiding selection bias. The registry can be linked with data from high‐quality nationwide registries to confirm or challenge the reported associations of ELF MF exposure and diseases such as cancer, miscarriage, and Alzheimer's disease. Bioelectromagnetics. 2020;41:34–40 © 2019 Bioelectromagnetics Society.

    更新日期:2019-12-20
  • In Vitro Evaluation of the Effect of Stimulation with Magnetic Fields on Chondrocytes
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-11-17
    Juan Felipe Escobar; Juan Jairo Vaca‐González; Johana Maria Guevara; Jose Félix Vega; Yoshie Adriana Hata; Diego Alexander Garzón‐Alvarado

    Magnetic fields (MFs) have been used as an external stimulus to increase cell proliferation in chondrocytes and extracellular matrix (ECM) synthesis of articular cartilage. However, previously published studies have not shown that MFs are homogeneous through cell culture systems. In addition, variables such as stimulation times and MF intensities have not been standardized to obtain the best cellular proliferative rate or an increase in molecular synthesis of ECM. In this work, a stimulation device, which produces homogeneous MFs to stimulate cell culture surfaces was designed and manufactured using a computational model. Furthermore, an in vitro culture of primary rat chondrocytes was established and stimulated with two MF schemes to measure both proliferation and ECM synthesis. The best proliferation rate was obtained with an MF of 2 mT applied for 3 h, every 6 h for 8 days. In addition, the increase in the synthesis of glycosaminoglycans was statistically significant when cells were stimulated with an MF of 2 mT applied for 5 h, every 6 h for 8 days. These findings suggest that a stimulation with MFs is a promising tool that could be used to improve in vitro treatments such as autologous chondrocyte implantation, either to increase cell proliferation or stimulate molecular synthesis. Bioelectromagnetics. 2020;41:41–51 © 2019 Bioelectromagnetics Society

    更新日期:2019-12-20
  • Moderate Intensity Static Magnetic Fields Prevent Thrombus Formation in Rats and Mice
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-04
    Qin Li; Zhongcai Liao; Lili Gu; Lei Zhang; Lingxi Zhang; Xiaofei Tian; Jun Li; Zhicai Fang; Xinyue Zhang

    We established three types of thrombosis models to explore the effects of the static magnetic field (SMF) on thrombosis in rats and mice with three different MF intensities. In the carrageenan‐induced thrombosis model in rats, the SMF treatments reduced the black tail length of rats, extracorporeal thrombus, and the mass of wet and dry thrombus, and improved the coagulation index value. In FeCl3‐induced arterial thrombosis model in rats, the SMF treatment showed some anti‐thrombotic effects. More specifically, the SMF treatment affected rodent blood pressure, plasma plasminogen activator inhibitor, tissue‐type plasminogen activator, thrombus mass, and thrombus protein content. In the adrenaline‐induced thrombosis model in mice, the SMF treatment had certain effects on the diameter and blood flow velocity of mouse auricle microcirculation in fine veins and arteries. Overall, the highest MF intensities we tested, 20–150 mT, showed a trend of anti‐thrombotic effect, indicating that the moderate‐intensity SMF might serve as a potential treatment for clot‐related diseases in the future. Bioelectromagnetics. 2020;41:52–62 © 2019 Bioelectromagnetics Society.

    更新日期:2019-12-20
  • Perturbing Circadian Oscillations in an In Vitro Suprachiasmatic Nucleus With Magnetic Stimulation
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-12-19
    Binyam T. Kassahun; Martin Bier; Jian Ding

    Many neurological disorders are associated with abnormal oscillatory dynamics. The suprachiasmatic nucleus (SCN) is responsible for the timing and synchronization of physiological processes. We performed experiments on PERIOD2::LUCIFERASE transgenic “knock‐in” mice. In these mice, a gene that is expressed in a circadian pattern is fused to an inserted gene that codes for luciferase, which is a bioluminescent enzyme. A one‐time 3 min magnetic stimulation (MS) was applied to excised slices of the SCN. The MS consisted of a 50‐mT field that was turned on and off 4,500 times. The rise time and fall time of the field were 75 μs. A photon count that extended over the full 5 days that the slice remained viable, subsequently revealed how the MS affected the circadian cycle. The MS was applied at points in the circadian cycle that correspond to either maximal or minimal bioluminescence. It was found that both the amplitude and period of the endogenous circadian oscillation are affected by MS and that the effects strongly depend on where in the circadian cycle the stimulation was applied. Our MS dose is in the same range as clinically applied doses, and our findings imply that transcranial MS may be instrumental in remedying disorders that originate in circadian rhythm abnormalities. Bioelectromagnetics. 2020;41:63–72 © 2019 Wiley Periodicals, Inc.

    更新日期:2019-12-20
  • RF Energy Absorption in Human Bodies Due to Wearable Antennas in the 2.4 GHz Frequency Band
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-11-19
    Marta Fernandez; Hugo G. Espinosa; David Guerra; Iván Peña; David V. Thiel; Amaia Arrinda

    Human exposure to electromagnetic fields produced by two wearable antennas operating in the 2.4 GHz frequency band was assessed by computational tools. Both antennas were designed to be attached to the skin, but they were intended for different applications. The first antenna was designed for off‐body applications, i.e. to communicate with a device placed outside the body, while the second antenna model was optimized to communicate with a device located inside the body. The power absorption in human tissues was determined at several locations of adult male and female body models. The maximum specific absorption rate (SAR) value obtained with the off‐body antenna was found on the torso of the woman model and was equal to 0.037 W/kg at 2.45 GHz. SAR levels increased significantly for the antenna transmitting inside the body. In this case, SAR values ranged between 0.23 and 0.45 W/kg at the same body location. The power absorbed in different body tissues and total power absorbed in the body were also calculated; the maximum total power absorbed was equal to 5.2 mW for an antenna input power equal to 10 mW. Bioelectromagnetics. 2020;41:73–79 © 2019 Wiley Periodicals, Inc.

    更新日期:2019-12-20
  • Melatonin Levels and Low‐Frequency Magnetic Fields in Humans and Rats: New Insights From a Bayesian Logistic Regression
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-09-29
    Nicolas F. Bouché, Kevin McConway

    The present analysis revisits the impact of extremely low‐frequency magnetic fields (ELF‐MF) on melatonin (MLT) levels in human and rat subjects using both a parametric and non‐parametric approach. In this analysis, we use 62 studies from review articles. The parametric approach consists of a Bayesian logistic regression (LR) analysis and the non‐parametric approach consists of a Support Vector analysis, both of which are robust against spurious/false results. Both approaches reveal a unique well‐ordered pattern, and show that human and rat studies are consistent with each other once the MF strength is restricted to cover the same range (with B ≲ 50 μT). In addition, the data reveal that chronic exposure (longer than ∼22 days) to ELF‐MF appears to decrease MLT levels only when the MF strength is below a threshold of ~30 μT (), i.e., when the man‐made ELF‐MF intensity is below that of the static geomagnetic field. Studies reporting an association between ELF‐MF and changes to MLT levels and the opposite (no association with ELF‐MF) can be reconciled under a single framework. Bioelectromagnetics. 2019;40:539–552. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • Millimeter‐Wave Heating in In Vitro Studies: Effect of Convection in Continuous and Pulse‐Modulated Regimes
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-10-03
    Rosa Orlacchio, Maxim Zhadobov, Stanislav I. Alekseev, Denys Nikolayev, Ronan Sauleau, Yann Le Page, Yves Le Dréan

    Shallow penetration of millimeter waves (MMW) and non‐uniform illumination in in vitro experiments result in a non‐uniform distribution of the specific absorption rate (SAR). These SAR gradients trigger convective currents in liquids affecting transient and steady‐state temperature distributions. We analyzed the effect of convection on temperature dynamics during MMW exposure in continuous‐wave (CW) and pulsed‐wave (PW) amplitude‐modulated regimes using micro‐thermocouples. Temperature rise kinetics are characterized by the occurrence of a temperature peak that shifts to shorter times as the SAR of the MMW exposure increases and precedes initiation of convection in bulk. Furthermore, we demonstrate that the liquid volume impacts convection. Increasing the volume results in earlier triggering of convection and in a greater cooling rate after the end of the exposure. In PW regimes, convection strongly depends on the pulse duration that affects the heat pulse amplitude and cooling rate. The latter results in a change of the average temperature in PW regime. Bioelectromagnetics. 2019;40:553–568. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • Characterization of Levels of Extremely Low Frequency Magnetic Fields Emitted From Portable Hand‐Held Fans
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-08-02
    Sangjun Choi, Soyeon Kim, Seoyoun Bae, Won Kim, Ju‐Hyun Park, Eunkyo Chung, Jihoon Park, Dong‐Uk Park

    This study aims to assess the levels of extremely low frequency magnetic fields (ELF‐MF) emitted from portable hand‐held fans (HHFs) and their principal frequency and to identify factors influencing these levels. We collected a total of eleven models of HHF and monitored the ELF‐MF as a function of fan speed and distance from the fan. EMDEX II was used to monitor the ELF‐MF. An SMP2 EMF‐meter equipped with a P400 field probe was used to determine the levels of ELF‐MF and the frequency spectrum. Ten of the fans, excluding only one bladeless‐fan model, emitted a high level of ELF‐MF near the source of the HHF direct‐current motor. The maximum measured level of ELF‐MF ranged from 14.07 to 218.7 µT. All measurements of the ELF‐MF taken within 10 cm from the HHFs showed values higher than 1.0 µT. ELF‐MF levels were found to decrease markedly with distance, regardless of the HHF product. The level of ELF‐MF rose noticeably with increased fan speed. The speed of and distance from the HHF significantly influenced the level of ELF‐MF. All principal frequencies ranged from 1 to 300 Hz, which falls in the typical range of ELF. Bioelectromagnetics. 2019;40:569–577. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • Effects of 171 MHz Low‐Intensity Electromagnetic Field on Glucocorticoid and Mineral Corticoid Activity of the Adrenal Glands of Rats
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-10-22
    Sergey Perov, Nina Rubtsova, Quirino Balzano

    A sub‐acute electromagnetic field (EMF) biological effect study was carried out on rats exposed in the Transverse ElectroMagnetic exposure chamber at 171 MHz Continuous Wave (CW). The experiments involved three exposure levels (15, 25, and 35 V/m) for 15 days with triplicate parallel sham‐exposed controls in each series. All exposure conditions were simulated for the evaluation of the electromagnetic energy distribution and specific absorption rate (SAR) in the rat phantoms. Studies have shown a biphasic biological response depending on time and absorbed electromagnetic energy. Under low SAR, approximately 0.006 W/kg, EMF exposure leads to the stimulation of adrenal gland activity. This process is accompanied by an initial increase of daily excretion of corticosterone and Na+, which is seen as a higher Na+/K+ ratio, followed by a decrease of these parameters over time. It is possible that EMF exposure causes a stress response in animals, which is seen as an increased adrenal activity. Bioelectromagnetics. 2019;40:578–587. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • T‐Cell Differentiation to T Helper 9 Phenotype is Elevated by Extremely Low‐Frequency Electromagnetic Fields Via Induction of IL‐2 Signaling
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-10-29
    Ye Won Jang, Ki Cheol Gil, Ji Soo Lee, WonKu Kang, So‐Young Park, Kwang Woo Hwang

    Owing to the development of information technology and the electronics industry, and the increase in the use of electronic products, an increasing number of people are exposed to electromagnetic fields (EMFs) in daily life. There has been concern about the effects of EMFs on the human body. Th9 cells, which are characterized by the generation of interleukin‐(IL‐9), are a recently defined subset of T helper (Th) cells. In this study, we investigated the effect of extremely low‐frequency (60 Hz) EMFs, such as those generated by household power sources, at 0.8 mT intensity on CD4+ T cells. The exposure of CD4+ T cells to such EMFs under Th9‐polarizing conditions increased IL‐9 secretion and gene expression of transcription factors that are important for Th9 development. The expression of GATA3 increased in the early stage, and the phosphorylation of STAT5 and STAT6, which regulate the expression of GATA3, increased. In addition, EMFs increased the expression of IL‐2 by the T cells. In conclusion, the differentiation of CD4+ T cells to the Th9 phenotype was increased by exposure to extremely low‐frequency EMFs, and this appeared to be dependent on the IL‐2 signaling pathway. Furthermore, co‐cultures of EMF‐exposed Th9 cells and mast cells showed an increased expression of mast cell proteases, FcεR1α, and mast cell‐derived inflammatory cytokines compared with co‐cultures of non‐EMF‐exposed Th9 cells and mast cells. Our results suggest that EMFs enhance the differentiation of CD4+ T cells to the Th9 phenotype, resulting in mast cell activation and inflammation. Bioelectromagnetics. 2019;40:588–601. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • Evaluation of Radiofrequency and Extremely Low‐Frequency Field Levels at Children's Playground Sites in Greece From 2013 to 2018
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-09-20
    Maria Christopoulou, Efthymios Karabetsos

    From 2013 to 2018, in‐situ measurements of radiofrequency (RF) electromagnetic fields (EMF) and extremely low‐frequency (ELF) electric and magnetic fields in 317 existing and under‐construction children's playground facilities, in 16 municipalities all over Greece, were carried out by the Greek Atomic Energy Commission (EEAE). These measurements were conducted following legislative framework established in 2009, which requires that compliance with the established exposure limits for EMFs should be verified in playground areas. The results are presented by the value of the electric field (E) and exposure ratio (Λ) for the RF EMF, as well as the value of the electric field (E) and magnetic flux density (B) for the ELF electric and magnetic fields. Statistical analysis tools were applied on measurement data and conclusions have been made, taking into consideration: (i) environment type (urban/suburban), and (ii) vicinity to any transmitting installations. Measurement results correspond to the typical EMF background levels for each environment type. Concerning the environment type, RF EMF, and ELF electric/magnetic field measurements reveal no differentiation between urban and suburban environments. Bioelectromagnetics. 2019;40:602–605. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-20
  • Proposal of 28 GHz In Vitro Exposure System Based on Field Uniformity for Three‐Dimensional Cell Culture Experiments
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-08-20
    Young Seung Lee, Jae‐Young Chung, Sang Bong Jeon, Ae‐Kyoung Lee, Hyung‐Do Choi

    This paper proposes a novel in vitro exposure system operating at millimeter‐wave (mmWave) 28 GHz, one of the frequency bands under consideration for fifth generation (5G) communication. We employed the field uniformity concept along cross‐sectional observation planes at shorter distances from the radiation antenna for better efficiency and a small‐size system. A choke‐ring antenna was designed for this purpose in consideration of a wider beamwidth (BW) and a symmetric far‐field pattern across three principal planes. The permittivity of Dulbecco's modified Eagle's medium solution was measured to examine the specific absorption rate (SAR) of the skin cell layer inside a Petri dish model for a three‐dimensional (3D) cell culture in vitro experiment. The best deployment of Petri dishes, taking into account a geometrical field symmetry, was proposed. Local SAR values within the cell layer among the Petri dishes were determined with different polarization angles. It was determined that this polarization effect should be considered when the actual exposure and deployment were conducted. We finally proposed an in vitro exposure system based on the field uniformity including downward exposure from an antenna for 3D cell culture experiments. A small‐size chamber system was obtained, and the size was estimated using the planar near‐field chamber design rule. Bioelectromagnetics. 2019;40:445–457. © 2019 Bioelectromagnetics Society

    更新日期:2019-11-04
  • Anatomical Model Uncertainty for RF Safety Evaluation of Metallic Implants Under MRI Exposure
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-08-08
    Aiping Yao, Earl Zastrow, Eugenia Cabot, Bryn Lloyd, Beatrice Schneider, Wolfgang Kainz, Niels Kuster

    The Virtual Population (ViP) phantoms have been used in many dosimetry studies, yet, to date, anatomical phantom uncertainty in radiofrequency (RF) research has largely been neglected. The objective of this study is to gain insight, for the first time, regarding the uncertainty in RF‐induced fields during magnetic resonance imaging associated with tissue assignment and segmentation quality and consistency in anatomical phantoms by evaluating the differences between two generations of ViP phantoms, ViP1.x and ViP3.0. The RF‐induced 10g‐average electric (E‐) fields, tangential E‐fields distribution along active implantable medical devices (AIMD) routings, and estimated AIMD heating were compared for five phantoms that are part of both ViP1.x and ViP3.0. The results demonstrated that differences exceeded 3 dB (−29%, +41%) for local quantities and 1 dB (±12% for field, ±25% for power) for integrated and volume‐averaged quantities (e.g., estimated AIMD‐heating and 10 g‐average E‐fields), while the variation across different ViP phantoms of the same generation can exceed 10 dB (−68% and +217% for field, −90% and +900% for power). In conclusion, the anatomical phantom uncertainty associated with tissue assignment and segmentation quality/consistency is larger than previously assumed, i.e., 0.6 dB or ±15% (k = 1) for AIMD heating. Further, multiple phantoms based on different volunteers covering the target population are required for quantitative analysis of dosimetric endpoints, e.g., AIMD heating, which depend on patient anatomy. Phantoms with the highest fidelity in tissue assignment and segmentation should be used, as these ensure the lowest uncertainty and possible underestimation of exposure. To verify that the uncertainty decreases monotonically with improved phantom quality, the evaluation of differences between phantom generations should be repeated for any improvement in segmentation. Bioelectromagnetics. 2019;40:458–471. © 2019 Bioelectromagnetics Society

    更新日期:2019-11-04
  • 3D Magnetopneumography Magnetic Dipole Model and Its Application Using Fluxgate Gradiometers
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-09-08
    Yunlong Fang

    Magnetopneumography (MPG) as a non‐invasive method for pneumoconiosis diagnosis has been developed to evaluate the load and spatial distribution of particles within the human lungs through scanning of remanent magnetic fields after magnetization of the subject in a strong direct current field. The measurement of particle spatial distribution is very important for pneumoconiosis diagnosis because localized deposits may be associated with some pathological changes such as pulmonary fibrosis. Previous research found that loads of magnetite particles were proportional to their magnetic dipole moments. The three‐dimensional (3D) MPG magnetic dipole model (MDM) proposed in this paper and based on Biot–Savart Law and matrix manipulation provides a means of precise measurement of the particle distribution and load amount. A styrofoam + magnetite powder phantom with magnetization was laid on a nonmagnetic board. Two first‐order fluxgate gradiometers with 10–12 T sensitivity were coaxially applied over and under the phantom and used for scanning remanent magnetic fields. This paper provides validation results using 3D MPG MDM through two experiments. The overall error of the simulation results is 0.2–2.7% in the center and 7.28–9.42% in the corners of the subject. Finally, this paper gives clinical experiments with a welder suffering stage‐II pneumoconiosis and states that the 3D MPG MDM shows similar results to X‐ray chest films in pneumoconiosis diagnosis. The results suggest that the 3D MPG MDM is potentially a reasonable and accurate algorithmic model to inversely track the load amount and distribution of magnetite particles within the lungs. Bioelectromagnetics. 2019;40:472–487. © 2019 Wiley Periodicals, Inc

    更新日期:2019-11-04
  • Application of Bio‐Impedance Analysis to Estimate the Condition of Yellowtail (Seriola quinqueradiata) Muscle at Different Storage Temperatures
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-08-07
    Pengxiang Yuan, Tong Jiang, Katsuya Hirasaka, Yao Wang, Kazuki Matsuo, Riho Miyazaki, Katsuyasu Tachibana, Shigeto Taniyama

    Changes in impedance at 2 kHz, adenosine triphosphate (ATP) content, and muscle contraction were evaluated in yellowtail during 0 (ice), 5, 10, 15, and 20°C storage. Histological changes during ice storage were also measured. At any temperature, although impedance increased with both rigor mortis and ATP consumption during early storage, it began to decrease rapidly when ATP was almost depleted. Moreover, temporarily increasing impedance had a strong relationship with ATP content; decreasing impedance had a significant correlation with storage temperature after ATP depletion. Furthermore, impedance increased with narrowing of intercellular spaces when sarcolemma was intact and decreased with expansion of intercellular spaces when sarcolemma was leaky. Meanwhile, changes of sarcolemma and intercellular spaces were accompanied by ATP change. Thus, ATP is one significant physiological factor for impedance change, and temperature greatly influenced impedance after depletion of ATP. Results suggest that impedance analysis can be used as a convenient and nondestructive method to diagnose condition of tissue at different storage temperatures. Bioelectromagnetics. 2019;40:488–497. © 2019 Bioelectromagnetics Society

    更新日期:2019-11-04
  • Early‐Life Exposure to Pulsed LTE Radiofrequency Fields Causes Persistent Changes in Activity and Behavior in C57BL/6 J Mice
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-09-15
    Kerry A. Broom, Richard Findlay, Darren S. Addison, Cristian Goiceanu, Zenon Sienkiewicz

    Despite much research, gaps remain in knowledge about the potential health effects of exposure to radiofrequency (RF) fields. This study investigated the effects of early‐life exposure to pulsed long term evolution (LTE) 1,846 MHz downlink signals on innate mouse behavior. Animals were exposed for 30 min/day, 5 days/week at a whole‐body average specific energy absorption rate (SAR) of 0.5 or 1 W/kg from late pregnancy (gestation day 13.5) to weaning (postnatal day 21). A behavioral tracking system measured locomotor, drinking, and feeding behavior in the home cage from 12 to 28 weeks of age. The exposure caused significant effects on both appetitive behaviors and activity of offspring that depended on the SAR. Compared with sham‐exposed controls, exposure at 0.5 W/kg significantly decreased drinking frequency (P ≤ 0.000) and significantly decreased distance moved (P ≤ 0.001). In contrast, exposure at 1 W/kg significantly increased drinking frequency (P ≤ 0.001) and significantly increased moving duration (P ≤ 0.005). In the absence of other plausible explanations, it is concluded that repeated exposure to low‐level RF fields in early life may have a persistent and long‐term effect on adult behavior. Bioelectromagnetics. 2019;40:498–511. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

    更新日期:2019-11-04
  • Magnetic Resonance Examinations of Patients With Implanted Active Devices. A Low‐Cost Approach in Slew Rate Evaluation
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-28
    Diego Trevisan, Claudio Nichelatti, Marta Maieron, Aldo Valentini

    Time‐varying magnetic field gradients involved in magnetic resonance examinations can damage implanted electronic systems. The quantity related to this side effect is the gradient slew rate, which is usually not directly available on magnetic resonance console. The present study proposes a low‐cost approach in slew rate assessment, which is useful in risks versus benefits evaluation as well as in sequences optimization. The experimental method is based on an analog circuit, which senses the output voltage of the scanner waveform generator. This allows taking easy and reliable slew rate measurements, even during clinical examinations on patients. Whereas previous studies required managing a considerable amount of data, the present work addresses only the maximal slew rate of any clinical sequence. Experimental results show that the smooth gradient mode, selectable on the two scanners examined, is very effective in patient safety improvement. In particular, it reduces slew rate values in the range from 52.4 up to 132.4 T m‐1 s‐1, i.e. far below the interval 216–346 T m‐1 s‐1, indicated as slew rate tolerance limit of modern implanted electronic devices. Bioelectromagnetics. 2019;40:512–521. © 2019 Bioelectromagnetics Society

    更新日期:2019-11-04
  • 更新日期:2019-11-01
  • 更新日期:2019-11-01
  • The Effect of Extremely Low-Frequency Electromagnetic Fields on the Prevalence of Musculoskeletal Disorders and the Role of Oxidative Stress.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-20
    Majid Bagheri Hosseinabadi,Narges Khanjani

    Extremely low-frequency electromagnetic fields (ELF-EMFs) may cause negative health effects. This study aimed to investigate the direct and indirect effects of chronic exposure to extremely low-frequency electric and magnetic fields on the prevalence of musculoskeletal disorders (MSDs). In this cross-sectional study, 152 power plant workers were enrolled. The exposure level of employees was measured based on the IEEE Std C95.3.1 standard. Superoxide dismutase (SOD), catalase (Cat), glutathione peroxidase (GPx), total antioxidant capacity (TAC), and malondialdehyde (MDA) (independent variables) were measured in the serum of subjects. The Nordic musculoskeletal questionnaire was used to assess MSDs (dependent variable). The mean exposure of electric and magnetic fields were 4.09 V/m (standard deviation [SD] = 4.08) and 16.27 µT (SD = 22.99), respectively. Increased levels of SOD, Cat, GPx, and MDA had a direct significant relation with MSDs. In the logistic regression model, SOD (odds ratio [OR] = 0.952, P = 0.026), GPx (OR = 0.991, P = 0.048), and MDA (OR = 0.741, P = 0.021) were significant predictors of MSDs. ELF-EMFs were not related to MSDs directly; however, increased levels of oxidative stress may cause MSDs. Bioelectromagnetics. 2019;40:354-360. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Effects of RF-EMF on the Human Resting-State EEG-the Inconsistencies in the Consistency. Part 1: Non-Exposure-Related Limitations of Comparability Between Studies.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-20
    Heidi Danker-Hopfe,Torsten Eggert,Hans Dorn,Cornelia Sauter

    The results of studies on possible effects of radiofrequency electromagnetic fields (RF-EMFs) on human waking electroencephalography (EEG) have been quite heterogeneous. In the majority of studies, changes in the alpha-frequency range in subjects who were exposed to different signals of mobile phone-related EMF sources were observed, whereas other studies did not report any effects. In this review, possible reasons for these inconsistencies are presented and recommendations for future waking EEG studies are made. The physiological basis of underlying brain activity, and the technical requirements and framework conditions for conducting and analyzing the human resting-state EEG are discussed. Peer-reviewed articles on possible effects of EMF on waking EEG were evaluated with regard to non-exposure-related confounding factors. Recommendations derived from international guidelines on the analysis and reporting of findings are proposed to achieve comparability in future studies. In total, 22 peer-reviewed studies on possible RF-EMF effects on human resting-state EEG were analyzed. EEG power in the alpha frequency range was reported to be increased in 10, decreased in four, and not affected in eight studies. All reviewed studies differ in several ways in terms of the methodologies applied, which might contribute to different results and conclusions about the impact of EMF on human resting-state EEG. A discussion of various study protocols and different outcome parameters prevents a scientifically sound statement on the impact of RF-EMF on human brain activity in resting-state EEG. Further studies which apply comparable, standardized study protocols are recommended. Bioelectromagnetics. 2019;40:291-318. © 2019 The Authors. Bioelectromagnetics Published by Wiley Periodicals, Inc.

    更新日期:2019-11-01
  • Nonlinear Dispersive Model of Electroporation for Irregular Nucleated Cells.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-11
    Michele Alessandro Chiapperino,Pietro Bia,Diego Caratelli,Johan Gielis,Luciano Mescia,Janja Dermol-Černe,Damijan Miklavčič

    In this work, the electroporation phenomenon induced by pulsed electric field on different nucleated biological cells is studied. A nonlinear, non-local, dispersive, and space-time multiphysics model based on Maxwell's and asymptotic Smoluchowski's equations has been developed to calculate the transmembrane voltage and pore density on both plasma and nuclear membrane perimeters. The irregular cell shape has been modeled by incorporating in the numerical algorithm the analytical functions pertaining to Gielis curves. The dielectric dispersion of the cell media has been modeled considering the multi-relaxation Debye-based relationship. Two different irregular nucleated cells have been investigated and their response has been studied applying both the dispersive and non-dispersive models. By a comparison of the obtained results, differences can be highlighted confirming the need to make use of the dispersive model to effectively investigate the cell response in terms of transmembrane voltages, pore densities, and electroporation opening angle, especially when irregular cell shapes and short electric pulses are considered. Bioelectromagnetics. 2019;40:331-342. © 2019 Wiley Periodicals, Inc.

    更新日期:2019-11-01
  • Novel ETV6-RUNX1 Mouse Model to Study the Role of ELF-MF in Childhood B-Acute Lymphoblastic Leukemia: a Pilot Study.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-04
    Elena Campos-Sanchez,Carolina Vicente-Dueñas,Guillermo Rodríguez-Hernández,Myles Capstick,Niels Kuster,Clemens Dasenbrock,Isidro Sánchez-García,César Cobaleda

    Exposure to extremely low-frequency magnetic fields (ELF-MFs) has been classified by the International Agency for Research on Cancer (IARC) as "possibly carcinogenic to humans," based on limited scientific evidence concerning childhood leukemia. This assessment emphasized the lack of appropriate animal models recapitulating the natural history of this disease. Childhood B-cell acute lymphoblastic leukemia (B-ALL) is the result of complex interactions between genetic susceptibility and exposure to exogenous agents. The most common chromosomal alteration is the ETV6-RUNX1 fusion gene, which confers a low risk of developing the malignancy by originating a preleukemic clone requiring secondary hits for full-blown disease to appear. To develop potential prophylactic interventions, we need to identify the environmental triggers of the second hit. Recently, we generated a B-ALL mouse model of the human ETV6-RUNX1+ preleukemic state. Here, we present the results from the ARIMMORA pilot study, obtained by exposing 34 Sca1-ETV6-RUNX1 mice (vs. 27 unexposed) to a 50 Hz magnetic field of 1.5 mT with both fundamental and harmonic content, with an on/off cycle of 10 min/5 min, for 20 h/day, from conception until 3 months of age. Mice were monitored until 2 years of age and peripheral blood was periodically analyzed by flow cytometry. One of the exposed mice developed B-ALL while none of the non-exposed did. Although the results are statistically non-significant due to the limited number of mice used in this pilot experiment, overall, the results show that the newly developed Sca1-ETV6-RUNX1 mouse can be successfully used for ELF-MF exposure studies about the etiology of childhood B-ALL. Bioelectromagnetics. 2019;40:343-353. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Effects of 5-HT1 and 5-HT 2 Receptor Agonists on Electromagnetic Field-Induced Analgesia in Rats.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-06-04
    Ercan Ozdemir,Ayse Demirkazik,Ahmet Sevki Taskıran,Gokhan Arslan

    Much evidence demonstrates the antinociceptive effect of magnetic fields (MFs). However, the analgesic action mechanism of the electromagnetic field (EMF) is not exactly understood. The aim of the present study was to investigate the effects of 5-HT1 and 5-HT2 receptor agonists (serotonin HCl and 2,5-dimethoxy-4-iodoamphetamine [DOI] hydrochloride) on EMF-induced analgesia. In total, 66 adult male Wistar albino rats with an average body mass of 225 ± 13 g were used in this study. The animals were subjected to repeated exposures of alternating 50 Hz and 5 mT EMF for 2 h a day for 15 days. Prior to analgesia tests, serotonin HCl (5-HT1 agonist) 4 mg/kg, WAY 100635 (5-HT1 antagonist) 0.04 mg/kg, DOI hydrochloride (5-HT2 receptor agonist) 4 mg/kg, and SB 204741 (5-HT2 antagonist) 0.5 mg/kg doses were injected into rats. For statistical analysis of the data, analysis of variance was used and multiple comparisons were determined by Tukey's test. Administration of serotonin HCl MF (5 mT)-exposed rats produced a significant increase in percent maximal possible effect (% MPE) as compared with EMF group (P < 0.05). On the contrary, injection of WAY 100635 to MF-exposed rats produced a significant decrease in analgesic activity (P < 0.05). Similarly, the administration of DOI hydrochloride significantly increased % MPE values as compared with the EMF group while SB 204741 reduced it (P < 0.05). In conclusion, our results suggested that serotonin 5-HT1 and 5-HT2 receptors play an important role in EMF-induced analgesia; however, further research studies are necessary to understand the mechanism. Bioelectromagnetics. 2019;40:319-330. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Optimal currents for electrical stimulation of bone fracture repair: A computational analysis including variations in frequency, tissue properties, and fracture morphology.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-03-05
    Amin Zeighami,Farhad Alizadeh,Mehrdad Saviz

    Fracture healing happens naturally in most bone break cases. Occasionally prolongation of restoration period or non-union of the fracture may occur, where electrical stimulation has been shown to facilitate bone restoration by stimulating osteoblasts. Despite clinical use, a comprehensive computational model linking the applied currents to the stimulating field in the fracture has been missing. In this paper, we investigate the input current needed to stimulate osteoblasts in a fracture in the human forearm. Optimal current is computed for various fracture configurations, and sensitivity to frequency and inter/intrapersonal variance in dielectric properties are analyzed. Stimulation thresholds at the fracture site are based on detailed review of experimental studies. Our results show that for a 1 mm thick 30° fracture with a 15 Hz sinusoidal field, the input current amounts to a maximum of 3.77 µA. Minimum and maximum required current levels are plotted versus fracture parameters, all of which comply with the ICNIRP standard. Simulation results are supported by several experimental reports. Our model is useful for understanding the effects of various geometrical and electrical factors on clinical outcome, and serves as a theoretical aid in the design of more efficient systems. Bioelectromagnetics. 40:128-135, 2019. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Myrciaria dubia "camu camu" flour as a magnetoprotector in male mouse infertility.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-03-05
    Lizeth Torres,Bladimir Guevara,Víctor Cruz,Martha Valdivia

    Possible adverse effects of extremely low frequency magnetic fields (ELF-MF) are linked to a decrease of antioxidant defenses and the production of free radicals. The increase of free radicals affects the mitochondrial functionality inducing apoptosis, which affects the phosphorylation and generation of key ATP in fertilization. Myrciaria dubia, known as "camu camu," is a fruit with high levels of ascorbic acid, which exerts an important antioxidant function in the prevention of premature cell damage. In this study, the effect of Myrciaria dubia flour on oxidative damage produced by ELF-MF (610 μT) was evaluated by detecting the activity of endogenous mitochondrial oxidoreductase enzymes in a complete sperm cycle of mice. We found that the MF caused a significant (P < 0.05) decrease in sperm quality, whereas the groups supplied with Myrciaria dubia flour (50 and 75 mg/kg of body mass) in ELF-MF exposure showed a significant recovery (P < 0.05) in parameters of viability, percentage of plasma membrane integrity and mitochondrial activity, and index of epidymal sperm. This suggests that Myrciaria dubia flour would have an antioxidant activity that counteracts the damaging effects of ELF-MF in spermatogenesis and could be used as a natural ELF-MF protector. Bioelectromagnetics. 40:91-103, 2019. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Global gene expression changes reflecting pleiotropic effects of Irpex lacteus induced by low--intensity electromagnetic field.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-02-21
    Ling Sun,Xinyi Li,Haile Ma,Ronghai He,Prince O Donkor

    A polysaccharide of Irpex lacteus, a white-rot fungus with lignocellulose-degrading activities, has been used as a commercial medicine for nephritis treatment. Previously, a low-intensity electromagnetic field (LI-EMF) was found to increase the biomass and polysaccharide content of Irpex lacteus and induce twists on the cell surface. In this study, RNA-sequencing (RNA-seq) technology was used to analyze the underlying mechanism of LI-EMF's influence on Irpex lacteus. We identified 3268, 1377, and 941 differentially expressed genes (DEGs) in the LI-EMF-treated samples at recovery times of 0 h, 3 h, and 6 h, respectively, indicating a significant decline in the influence of the LI-EMF treatment on Irpex lacteus with the passage of recovery time. Moreover, 30 upregulated and 14 downregulated DEGs overlapped in the LI-EMF-treated samples at the recovery times of 0 h, 3 h, and 6 h, implying the important lasting effects of LI-EMF. The reliability of the RNA-seq data were validated by quantitative real-time PCR (qRT-PCR). The DEGs related to transcription factors, cell proliferation, cell wall, membrane components, amino acid biosynthesis and metabolism, and polysaccharide biosynthesis and metabolism were significantly enriched in the LI-EMF-treated samples. The experiments confirmed that the LI-EMF treatment significantly increased the content of amino acids with a considerable increase in the content of essential amino acids. Therefore, the global gene expression changes explained the pleiotropic effects of Irpex lacteus induced by the LI-EMF treatment. These findings provide the requisite data for the appropriate design and application of LI-EMF in the fermentation of microorganisms to increase production. Bioelectromagnetics. 40:104-117, 2019. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Clinical results of pulsed signal therapy on patellofemoral syndrome with patellar chondropathy.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-02-15
    Riccardo Gomes Gobbi,Adriana Lúcia Pastore E Silva,Marco Kawamura Demange,José Ricardo Pécora,João Espregueira-Mendes,Gilberto Luis Camanho

    This study was designed to evaluate the effect of pulsed signal therapy (PST) on patellofemoral pain syndrome associated with patellar chondropathy. A prospective randomized double-blind placebo controlled trial included 25 patients (41 knees) between 20 and 50 years with pain due to isolated patellofemoral syndrome with chondropathy. PST group received nine 60-min daily sessions of PST treatment. Control group received the same protocol of blinded placebo treatment. The main outcome was change from baseline Kujala score at 3 months. After 3 months, patients in the control group received effective treatment (placebo post-treatment). All patients were then followed, for up to 12 months. Seventeen knees (5 males and 12 females, mean age 36.7 ± 7.9) received placebo and 24 knees (8 males and 16 females, mean age 35.5 ± 8.9) received PST. By the third month, PST group exhibited a mean change from baseline of 9.63 ± 7.5 Kujala points, compared to 0.53 ± 1.8 in the placebo group (P < 0.001). A significant progressive improvement was seen in the PST group between the 3rd and 6th and between the 6th and 12th month (P < 0.016). Patients initially allocated in the control group also improved at 3 months (P < 0.001) and 6 months (P = 0.005) post-effective treatment. In conclusion, PST in patellofemoral pain syndrome with chondropathy was effective compared to placebo at 3 months, showing an important improvement of Kujala score. The improvement was progressive and maintained up to 12 months. PST is safe and should be considered as a non-invasive option for management of this condition. Bioelectromagnetics. 40:83-90, 2019. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • Computational phantom study of frozen melanoma imaging at 0.45 terahertz.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-01-31
    Zoltan Vilagosh,Alireza Lajevardipour,Andrew W Wood

    Terahertz radiation (THz) is highly absorbed by liquid water. This creates the possibility of medical imaging on the basis of the water content difference between normal and diseased tissue. The effective penetration of THz is limited, however, to a tissue depth of 0.2-0.3 mm at body temperature. A unique feature of the 0.1-2.0 THz frequency is that there is a high disparity between liquid water absorption and ice absorption, with ice being 100 times more permeable to the radiation than liquid water. This results in 90% of the radiation surviving to 1.0 mm in ice, permitting the imaging of frozen tissues to a depth of 5.0 mm. This method is practical as an in vivo procedure before or during surgical excision. Finite difference time domain (FDTD) computational modeling of frozen normal skin and frozen melanoma was undertaken using tissue phantoms. The study suggests that sufficient contrast exists to differentiate normal frozen skin and melanoma on the basis of the difference of water content alone. When the melanin pigment in melanomas is modeled as a significant absorber of THz, the contrast changes. Based on the modeling, further exploration of the "THz-skin freeze" imaging technique is justified. In the modeling, the boundary between the frozen tissue and non-frozen tissue is shown to be strongly reflective. If the reflective properties of the boundary are substantiated, the "THz-skin freeze" technique will have applications in other areas of skin diagnostics and therapeutics. Bioelectromagnetics. 40:118-127, 2019. © 2019 Bioelectromagnetics Society.

    更新日期:2019-11-01
  • 更新日期:2019-11-01
  • Editorial.
    Bioelectromagnetics (IF 1.945) Pub Date : 2019-10-28
    James Lin

    更新日期:2019-11-01
  • Pulsed electromagnetic field therapy in the treatment of pain and other symptoms in fibromyalgia: A randomized controlled study.
    Bioelectromagnetics (IF 1.945) Pub Date : 2018-05-01
    Juhani Multanen,Arja Häkkinen,Pauli Heikkinen,Hannu Kautiainen,Sirpa Mustalampi,Jari Ylinen

    Low-energy pulsed electromagnetic field (PEMF) therapy has been suggested as a promising therapy to increase microcirculation, which is of great concern in patients with fibromyalgia. This study evaluated the effectiveness of PEMF therapy on the treatment of fibromyalgia. A group of 108 women with fibromyalgia were allocated to a 12-week treatment period with an active Bio-Electro-Magnetic-Energy-Regulation (BEMER) device and a similar treatment period with an inactive device. Each patient received active and sham treatments in a random order. Pain and stiffness were assessed on a visual analog scale (VAS, scale 0-100 mm), and functional status was assessed by the Fibromyalgia Impact Questionnaire (FIQ). Mean VAS pain scores before the active and sham treatment periods were 66 (SD 22) and 63 (SD 22), respectively. After treatment periods, mean VAS pain scores had decreased significantly in active treatment, -12, 95% CI [-18, -6], and in sham treatment, -11, 95% CI [-17, -5]. Similarly, the decrease in stiffness and FIQ index after both treatments was statistically significant. However, per-protocol analysis showed no differences between active and sham treatments at any of the outcomes. This study demonstrated that low-energy PEMF therapy was not efficient in reducing pain and stiffness or in improving functioning in women with fibromyalgia. Bioelectromagnetics. 39:405-413, 2018. © 2018 Wiley Periodicals, Inc.

    更新日期:2019-11-01
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  • Reply: comment by S. milham
    Bioelectromagnetics (IF 1.945) Pub Date : 2000-07-19
    Savitz

    更新日期:2019-11-01
  • Maternal exposure to magnetic fields from high-voltage power lines and the risk of birth defects.
    Bioelectromagnetics (IF 1.945) Pub Date : 2012-07-25
    Carlotta Malagoli,Catherine M Crespi,Rossella Rodolfi,Carlo Signorelli,Maurizio Poli,Paolo Zanichelli,Sara Fabbi,Sergio Teggi,Livia Garavelli,Gianni Astolfi,Elisa Calzolari,Carlo Lucenti,Marco Vinceti

    The issue of adverse human health effects due to exposure to electromagnetic fields is still unclear, and congenital anomalies are among the outcomes that have been inconsistently associated with such exposure. We conducted a population-based, case-control study to examine the risk of congenital anomalies associated with maternal exposure to magnetic fields (MF) from high-voltage power lines during pregnancy in a community in northern Italy. We identified 228 cases of congenital malformations diagnosed in live births, stillbirths, and induced abortions among women living in the municipality of Reggio Emilia during the period 1998-2006, and a reference group of healthy newborns was matched for year of birth, maternal age, and hospital of birth. We identified maternal residence during early pregnancy and used Geographic Information System to determine whether the residences were within geocoded corridors with MF ≥0.1 μT near high-voltage power lines, then calculated the relative risk (RR) of congenital anomalies associated with maternal exposure. One case and 5 control mothers were classified as exposed, and the RR associated with MF ≥0.1 μT was 0.2 (95% CI: 0.0-2.0) after adjusting for maternal education. While small or moderate effects may have gone undetected due to low statistical power, the results of this study overall do not provide support for major effects of a teratogenic risk due to exposure to MF during early pregnancy.

    更新日期:2019-11-01
  • Factors confounding cytosolic calcium measurements in Jurkat E6.1 cells during exposure to ELF magnetic fields.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Cheryl R McCreary,Alex W Thomas,Frank S Prato

    Reported changes in the cytosolic calcium concentration ([Ca2+](c)) as a result of exposure to extremely low frequency (ELF) magnetic fields (MF) have been equivocal. In this study, we examine the possibility that some of these differences are attributable to variability associated with the cell cycle, pH of the suspension medium, and response to a calcium agonist. We used a custom designed spectrofluorimeter to measure [Ca2+](c) in Indo 1-AM loaded Jurkat E6.1 cells suspended in conditioned RPMI 1640 medium containing 10% fetal bovine serum. Four exposures were examined: zero static MF (Null), 60 Hz 100 microT(peak) sinusoidal MF (AC), 78 microT static MF (DC), and the combination of the 60 Hz and the 78 microT static MF (AD + DC). A significant decrease in normalized [Ca2+](c) values between 375-495 s for the DC and AC + DC groups was found in comparison to the Null group. However, statistical analysis indicated that cell cycle and quality of the alpha-CD3 monoclonal antibody response were significant covariates, while pH was not a significant covariate. When the effect of these covariates was taken into account, all exposure groups were significantly different from the control. Our results suggest that ELF MF effects may not be seen unless correction is made for biological variability of each cell preparation with respect to cell cycle and [Ca2+](c) response to antigen stimulation.

    更新日期:2019-11-01
  • Effect of magnetic field exposure on calcium channel currents using patch clamp technique.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Mayumi Obo,Shiro Konishi,Yoshihisa Otaka,Satoshi Kitamura

    Calcium influxes through the membrane of PC-12D cells were measured under exposure to DC biased AC magnetic fields in resonant conditions of the ion cyclotron and the ion parametric resonance hypotheses and compared with influxes in cells without exposure to the magnetic field. After cancellation of the geomagnetic field, the cells were exposed to the horizontal fields generated by a current sheet, a planar sheet of conductor which generated a satisfactorily homogeneous horizontal magnetic field on the stage of a microscope without hindering treatment of a cell under observation. At or near any resonant conditions, no change in calcium influx could be detected under standard patch clamp conditions.

    更新日期:2019-11-01
  • Effects of extremely low frequency (50 Hz) magnetic field on morphological and biochemical properties of human keratinocytes.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Vanessa Manni,Antonella Lisi,Deleana Pozzi,Sabrina Rieti,Annalucia Serafino,Livio Giuliani,Settimio Grimaldi

    We investigated the effects on human keratinocytes (HaCaT) of exposure to a sinusoidal magnetic field of 2 mT (50 Hz). These cells are a good model for studying interaction of nonionising radiation, because they are not shielded from fields in vivo and also because they are resistant to both mechanical and thermal stimuli. We performed scanning microscopy which showed modification in shape and morphology in exposed cells. This modification is related to differential actin distribution as revealed by phalloidin fluorescence analysis. Moreover, the exposed cells show increased clonogenic capacity, as well as increased cellular growth as showed by clonogenicity assays and growth curves. Indirect immunofluorescence analysis using a fluorescent antibody against involucrin and beta4 integrin, which are respectively differentiation and adhesion markers, revealed an increase of involucrin expression and segregation of beta4 integrin in the cell membrane in cells exposed to 50 Hz; a higher percentage of the exposed cells shows a modified pattern of adhesion and differentiation markers. We also present evidence that exposure of HaCaT cells can interfere with protein kinase activity. Our observations confirm the hypothesis that electromagnetic fields at 50 Hz may modify cell membrane morphology and interfere with initiation of the signal cascade pathway and cellular adhesion.

    更新日期:2019-11-01
  • 50 Hz magnetic fields of varying flux intensity affect cell shape changes in invertebrate immunocytes: the role of potassium ion channels.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Enzo Ottaviani,Davide Malagoli,Alex Ferrari,Davide Tagliazucchi,Angela Conte,Fabriziomaria Gobba

    The effect induced by exposure to 50 Hz magnetic fields (MFs) in immunocytes from the mussel Mytilus galloprovincialis is evaluated. The whole animal was exposed for 15 and 30 min to MF intensities ranging from 200 to 1,000 microT. The changes in the cellular shape of immunocytes, expressed as shape factor (SF), were studied at different times after addition of the chemotacting substance N-formyl-Meth-Leu-Phe (fMLP). Results show that MFs provoke differing delays in fMLP-induced cellular shape changes: 200 microT are ineffective, while levels from 300 microT upwards cause a significant increase in immunocyte SF values compared to controls. Reactivation of the cells is possible up to an intensity of 600 microT. The use of PCO 400, an opener of ATP-sensitive K+ channels, shows that potassium channels are involved in the effect of MFs on M. galloprovincialis immunocytes.

    更新日期:2019-11-01
  • Comparison of three different ways of measuring distances between residences and high voltage power lines.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Karl Gerhard Blaasaas,Tore Tynes

    The aim of this study was to evaluate whether distance data based on calculations by use of digitalized geographical information systems (GIS) and distance data based on measurements on 1:5000 maps agree sufficiently with on site distance measurements to be used as input to magnetic field calculations in epidemiological studies. The analysis were performed by use of weighted kappa (kappa(w)) statistical method described by Bland and Altman for comparison of measures of agreement. Map measurements showed better agreement with on site measurements than GIS calculations did. However, we consider both methods appropriate for use in larger epidemiological studies if the results are interpreted with caution. GIS calculations have the advantage of being both time and cost saving.

    更新日期:2019-11-01
  • Proposed test for detection of nonlinear responses in biological preparations exposed to RF energy.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Quirino Balzano

    Demodulation of amplitude modulated radio frequency (RF) energy has been proposed as a mechanism for the biological responses to these fields. The experiment proposed here tests whether the electric and magnetic structures of biological cells exhibit the nonlinear responses necessary for demodulation. A high Q cavity and very low noise amplification can be used to detect ultraweak nonlinear responses that appear as a second harmonic of a RF field incident on the sample. Nonlinear fields scattered from metabolically active biological cells grown in monolayer or suspended in medium can be distinguished from nonlinearities of the apparatus. Estimates for the theoretical signal sensitivity and analysis of system noise indicate the possibility of detecting a microwave signal at 1.8 GHz (2nd harmonic of 900 MHz) as weak as one microwave photon per cell per second. The practical limit, set by degradation of the cavity Q, is extremely low compared to the much brighter thermal background, which has its peak in the infrared at a wavelength of about 17 microm and radiates 10(10) infrared photons per second per cell in the narrow frequency band within 0.5% of the peak. The system can be calibrated by introduction of known quantities of nonlinear material, e.g., a Schottky diode. For an input power of 160 microW at 900 MHz incident on such biological material, the apparatus is estimated to produce a robust output signal of 0.10 mV at 1.8 GHz if detected with a spectrum analyzer and a 30-dB gain low noise amplifier. The experimental threshold for detection of nonlinear interaction phenomena is 10(10) below the signal produced by a Schottky diode, giving an unprecedented sensitivity to the measurement of nonlinear energy conversion processes in living tissue.

    更新日期:2019-11-01
  • NF-kappaB DNA-binding activity after high peak power pulsed microwave (8.2 GHz) exposure of normal human monocytes.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Mohan Natarajan,Vijayalaxmi,Maria Szilagyi,Francis N Roldan,Martin L Meltz

    The hypothesis investigated is that exposure of a mammalian cell to high peak power pulsed RF, at the frequency of 8.2 GHz, can result in the activation of an important eukaryotic transcriptional regulator, nuclear factor kappa B (NF-kappaB). This DNA-binding protein controls genes involved in long term cellular regulation. The selection of 8.2 GHz was based on the availability of a high peak power pulsed RF transmitter. In these studies, triplicate cultures of human monocytes (Mono Mac-6) were exposed to the pulsed wave radiation. The peak to average power ratio was 455:1 (2.2 micros pulse width and pulse repetition rate of 1000 pulses/s). The average power density at the position of exposure was 50 W/m(2), and the mean SAR at the bottom of the culture flask was 10.8 +/- 7.1 W/kg. The FDTD analysis indicated that 10% of the cells had an SAR of 22-29 W/kg. The cells were exposed continuously for 90 min at 37 degrees C, reincubated at this temperature, and harvested 4 h postexposure. The nuclear extracts were analyzed by electrophoretic mobility shift assay. The results showed a profound increase (3.6-fold) in the DNA binding activity of NF-kappaB in monocytes at 4 h after the pulsed RF exposure compared to sham irradiated controls. Competition experiments with cold NF-kappaB- specific oligonucleotides confirmed the specificity of the DNA binding activity. These results provide evidence that high peak power pulsed radiofrequency radiation can perturb the cell and initiate cell signaling pathways. However, at this point, we are not prepared to advocate that the cause is a nonthermal mechanism. Because of the broad distribution of SAR's in the flask, experiments need to be performed to determine if the changes observed are associated with cells exposed to high or low SARs.

    更新日期:2019-11-01
  • Hypersensitivity symptoms associated with exposure to cellular telephones: no causal link.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Maila Hietanen,Anna-Maija Hämäläinen,Tuula Husman

    The hypothesis that there exist hypersensitive persons who perceive subjective symptoms from radiofrequency (RF) fields emitted by hand held mobile phones (cellular phones) was tested using double blind provocation experiments. We also tested whether sensitive subjects are able to determine whether the phone is on or off by sensing RF fields. The study group consisted of 20 volunteers (13 women and 7 men) who reported themselves as being sensitive to cellular phones. The RF exposure sources were one analogue NMT phone (900 MHz) and two digital GSM phones (900 and 1800 MHz). The duration of a test session was 30 min, and three or four sessions were performed in random order for each subject during 1 day. The subjects were asked to report symptoms or sensations as soon as they perceived any abnormal feelings. In addition, the subjects' blood pressure, heart rate, and breathing frequency were monitored every 5 min. The results of the study indicated that various symptoms were reported, and most of them appeared in the head region. However, the number of reported symptoms was higher during sham exposure than during real exposure conditions. In addition, none of the test persons could distinguish real RF exposure from sham exposure. Hence, we conclude that adverse subjective symptoms or sensations, though unquestionably perceived by the test subjects, were not produced by cellular phones.

    更新日期:2019-11-01
  • Study of thermal effects of ultrasound stimulation on fracture healing.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    Walter Hong-Shong Chang,Jui-Sheng Sun,Su-Pei Chang,James C Lin

    Low intensity ultrasound stimulation has been used as a strategy to promote fracture healing. This study investigated the mechanism of ultrasound stimulation in enhancing fracture healing. Forty-five adult New Zealand White rabbits were divided into control, microwave treated, and ultrasound stimulation groups. After anesthesia, transverse osteotomy was created at midportion of the fibula bone. Intravital staining followed by fluorescence microscopic examination of new bone formation in the osteotomy site and biomechanical tests on torsional stiffness of the osteotomy site were performed. The difference between each examination was evaluated and analyzed. After ultrasound stimulation, new bone formation in the osteotomy site of the stimulated limb was 23.1-35.8% faster than that of the sham treated limb; the torsional stiffness of the stimulated limb was 44.4-80.0% higher than that of the sham treated limb. In the group of microwave hyperthermia treatment, the new bone formation was higher than that of the sham treated limb, but the difference was not statistically significant. The difference in torsional stiffness between the microwave hyperthermia treated limbs and the sham treated limb was not quite statistically significant. We demonstrated that low intensity ultrasound stimulation could increase the new bone formation and torsional stiffness. These effects probably are not mediated via hyperthermia.

    更新日期:2019-11-01
  • Effects of exposure to low level radiofrequency fields on acetylcholine release in hippocampus of freely moving rats.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-04-12
    G Testylier,L Tonduli,R Malabiau,J C Debouzy

    Some central cholinergic effects have been reported in animals after acute exposure to radiofrequency electromagnetic field at low intensity. We studied acetylcholine (ACh) release in the brain of freely moving rats exposed for 1 h during the day to a 2.45 GHz continuous wave radiofrequency field (RF) (2 or 4 mW/cm(2)) or exposed for 1 or 14 h during the night to a 800 MHz field modulated at 32 Hz (AM 200 mW/cm(2)). Measurements were performed by microdialysis using a membrane implanted through the upper CA1 region of the hippocampus. After irradiation with the 2.45 GHz RF, rats exposed at 2 mW/cm(2) did not show a significant modification of Ach release, whereas those exposed at 4 mW/cm(2) showed a significant 40% decrease in mean ACh release from hippocampus. This decrease was maximal at 5 h post exposure. Exposure to the 800 MHz RF for 1 h did not cause any significant effect, but exposure for 14 hrs induced a significant 43% decrease in ACh release during the period 11 p.m.-4 a.m. compared to control rats. In the control group we observed an increase of ACh release at the beginning of the night, which was linked to the waking period of rats. This normal increase was disturbed in rats exposed overnight to the 800 MHz RF. This work indicates that neurochemical modification of the hippocampal cholinergic system can be observed during and after an exposure to low intensity RF.

    更新日期:2019-11-01
  • One week of exposure to 50 Hz, vertical magnetic field does not reduce urinary 6-sulphatoxymelatonin excretion of male wistar rats.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-03-14
    József Bakos,Noémi Nagy,György Thuróczy,László D Szabó

    The effect of exposure to 100 or 50 microT, 50 Hz, vertical magnetic field on the excretion of 6-sulphatoxymelatonin (6SM) in the nocturnal urine of rats was studied. Twelve male Wistar rats were kept under 12:12 hr light:dark conditions. The nocturnal urine of animals was collected in metabolic cages over 4 consecutive weeks. The concentration of 6SM in the rat urine was measured by 125I radioimmunoassay and normalized to creatinine concentration. After the first week of urine collection, 6 rats were exposed to 100 microT or 50 microT flux density magnetic fields (MF) for 8 hr daily for 1 week. It was found that the excretion of the primary metabolite of melatonin in the urine, 6SM, did not show statistically significant changes during and after magnetic field exposure.

    更新日期:2019-11-01
  • Increased mouse survival, tumor growth inhibition and decreased immunoreactive p53 after exposure to magnetic fields.
    Bioelectromagnetics (IF 1.945) Pub Date : 2002-03-14
    Santi Tofani,Marcella Cintorino,Domenico Barone,Michele Berardelli,Maria Margherita De Santi,Adriana Ferrara,Renzo Orlassino,Piero Ossola,Katia Rolfo,Flavio Ronchetto,Sergio Antonio Tripodi,Piero Tosi

    The possibility that magnetic fields (MF) cause antitumor activity in vivo has been investigated. Two different experiments have been carried out on nude mice bearing a subcutaneous human colon adenocarcinoma (WiDr). In the first experiment, significant increase in survival time (31%) was obtained in mice exposed daily to 70 min modulated MF (static with a superimposition of 50 Hz) having a time average total intensity of 5.5 mT. In the second independent experiment, when mice bearing tumors were exposed to the same treatment for four consecutive weeks, significant inhibition of tumor growth (40%) was reported, together with a decrement in tumor cell mitotic index and proliferative activity. A significant increase in apoptosis was found in tumors of treated animals, together with a reduction in immunoreactive p53 expression. Gross pathology at necroscopy, hematoclinical/hematological and histological examination did not show any adverse or abnormal effects. Since pharmacological rescue of mutant p53 conformation has been recently demonstrated, the authors suggest that MF exposure may obtain a similar effect by acting on redox chemistry connected to metal ions which control p53 folding and its DNA-binding activity. These findings support further investigation aimed at the potential use of magnetic fields as anti-cancer agents.

    更新日期:2019-11-01
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