1
|
Yamaguchi-Sekino S, Taki M, Ikuyo M, Esaki K, Aimoto A, Wake K, Kojimahara N. Assessment of combined exposure to intermediate-frequency electromagnetic fields and pulsed electromagnetic fields among library workers in Japan. Front Public Health 2022; 10:870784. [PMID: 35968480 PMCID: PMC9366663 DOI: 10.3389/fpubh.2022.870784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 07/05/2022] [Indexed: 11/13/2022] Open
Abstract
Objective To assess exposure levels to electromagnetic fields (EMFs) among library workers in Japan, focusing on co-exposure to intermediate-frequency EMF (IF-EMF) and pulsed EMF, to propose a new epidemiological research methodology. Methods The evaluated exposure sources were an electromagnetic type-electronic article surveillance gate (EM-EAS, IF-EMF (operating frequency 220 Hz-14 kHz)) and an activator/deactivator of anti-theft tags termed as “book check unit” (BCU, pulsed EMF). Short-term exposures were: (E1) whole-body exposure from the EAS gate when sitting within 3 m; (E2) local exposure to transient IF-EMF while passing through or beside the EAS gate; and (E3) local exposure to a pulsed magnetic field on BCU use. E1–E3 were evaluated based on exposure levels relative to magnetic flux density at the occupational reference level (RL; E1) or as per occupational basic restrictions (BR; E2 and E3) delineated by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) 2010 guidelines. Exposure indices based on mid-term exposure (D1–D3), assuming exposure according to employment on a weekly basis, were used to assess exposure in actual working conditions. D1 represents continuous exposure from an EAS gate when sitting within 3 m of the gate. D2 and D3 represent repeated transient exposures occurring during gate pass or on the operation of a BCU. A link to a web-based questionnaire was distributed to librarians working at all libraries where the authors had mailed institutional questionnaires (4,073 libraries). Four exposure patterns were defined according to various exposure scenarios. Results We obtained information on exposure parameters and working conditions from the 548 completed questionnaires. The ICNIRP guideline levels were not exceeded in any of the E1–E3 scenarios. Median of the D1 (% ICNIRP RL × hour/week) was 1, and >85% respondents had values <10. However, the maximum value was 513. Altogether, these results indicate that continuous exposure was low in most cases. The same tendency was observed regarding repeated transient exposure from EM-EAS gates (i.e., the median value for D2 (% ICNIRP BR × gate pass) was 5). However, there were several cases in which D1 and D2 values were >10 times the median. The median of D3 (% ICNIRP BR × BCU operation) was 10, and most respondents' D3 values were greater than their D2 values, although the derived results depended on the assumptions made for the estimation. Conclusion We conducted an assessment of combined exposures to IF-EMF and pulsed EMF among library workers in Japan by evaluating both short-term exposures (E1–E3) and exposure indices based on mid-term exposures (D1–D3) assuming actual working conditions per questionnaire results. These results provide useful information for future epidemiological studies.
Collapse
Affiliation(s)
- Sachiko Yamaguchi-Sekino
- Work Environment Research Group, National Institute of Occupational Safety and Health, Kawasaki, Japan
- *Correspondence: Sachiko Yamaguchi-Sekino
| | - Masao Taki
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| | - Miwa Ikuyo
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| | - Kaoru Esaki
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| | - Atsuko Aimoto
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Kanako Wake
- Strategic Planning Office, National Institute of Information and Communications Technology, Koganei, Japan
| | - Noriko Kojimahara
- Department of Epidemiology, Shizuoka Graduate University of Public Health, Shizuoka, Japan
| |
Collapse
|
2
|
Ikuyo M, Esaki K, Aimoto A, Wake K, Yamaguchi-Sekino S, Kojimahara N, Suzuki Y, Taki M. Measurement and Exposure Assessment of Intermediate Frequency Magnetic Fields From Electronic Article Surveillance (EAS) Gates in Libraries. Front Public Health 2022; 10:871134. [PMID: 35646792 PMCID: PMC9133885 DOI: 10.3389/fpubh.2022.871134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 03/28/2022] [Indexed: 11/17/2022] Open
Abstract
Exposure to magnetic fields from the electronic article surveillance (EAS) gate was evaluated in consideration of the application to epidemiological studies of library workers who are exposed continually to intermediate frequency magnetic fields from the EAS gate. Two types of exposures were investigated. One was transient exposure due to passing through or beside the gate and another was chronic exposure in the room. We measured magnetic fields from five EAS gate models which were commonly used in libraries in Japan. Detailed measurements were performed for two of them in consideration of the phase difference of vector components of magnetic flux density. The polarization of the magnetic field in the gate was investigated with the index of ellipticity. The induced electric field in a human body was numerically calculated for exposures to magnetic fields of the two gate models. The results provide a quantitative understanding of exposures during passing through or by the EAS gate. Magnetic field distribution was measured in a large room for one gate model to quantify the chronic exposure of library workers during the work at the desk. It was found that the magnetic field was distributed as a function of the horizontal distance to the nearest gatepost. The 45-point average value BIEC defined by the IEC standard was suggested to be a useful quantity to characterize the magnitude of the magnetic field from the EAS gate. Exposures to different EAS gates are expected to be compared through this quantity without detailed measurements. These results are expected to provide useful means for exposure assessment of epidemiological studies on the association between the IF-EMF exposure and possible health outcomes.
Collapse
Affiliation(s)
- Miwa Ikuyo
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| | - Kaoru Esaki
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Atsuko Aimoto
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| | - Sachiko Yamaguchi-Sekino
- Work Environment Research Group, National Institute of Occupational Safety and Health, Kawasaki, Japan
| | - Noriko Kojimahara
- Epidemiology, Shizuoka Graduate University of Public Health, Shizuoka, Japan
| | - Yukihisa Suzuki
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
| | - Masao Taki
- Department of Systems Design, Tokyo Metropolitan University, Hachioji, Japan
- Electromagnetic Compatibility Laboratory, National Institute of Information and Communications Technology, Koganei, Japan
| |
Collapse
|
3
|
Calderón C, Castaño-Vinyals G, Maslanyj M, Wiart J, Lee AK, Taki M, Wake K, Abert A, Badia F, Hadjem A, Kromhout H, de Llobet P, Varsier N, Conil E, Choi HD, Sim MR, Cardis E. Estimation of RF and ELF dose by anatomical location in the brain from wireless phones in the MOBI-Kids study. Environ Int 2022; 163:107189. [PMID: 35447435 DOI: 10.1016/j.envint.2022.107189] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 02/28/2022] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
Wireless phones (both mobile and cordless) emit not only radiofrequency (RF) electromagnetic fields (EMF) but also extremely low frequency (ELF) magnetic fields, both of which should be considered in epidemiological studies of the possible adverse health effects of use of such devices. This paper describes a unique algorithm, developed for the multinational case-control MOBI-Kids study, that estimates the cumulative specific energy (CSE) and the cumulative induced current density (CICD) in the brain from RF and ELF fields, respectively, for each subject in the study (aged 10-24 years old). Factors such as age, tumour location, self-reported phone models and usage patterns (laterality, call frequency/duration and hands-free use) were considered, as was the prevalence of different communication systems over time. Median CSE and CICD were substantially higher in GSM than 3G systems and varied considerably with location in the brain. Agreement between RF CSE and mobile phone use variables was moderate to null, depending on the communication system. Agreement between mobile phone use variables and ELF CICD was higher overall but also strongly dependent on communication system. Despite ELF dose distribution across the brain being more diffuse than that of RF, high correlation was observed between RF and ELF dose. The algorithm was used to systematically estimate the localised RF and ELF doses in the brain from wireless phones, which were found to be strongly dependent on location and communication system. Analysis of cartographies showed high correlation across phone models and across ages, however diagonal agreement between these cartographies suggest these factors do affect dose distribution to some level. Overall, duration and number of calls may not be adequate proxies of dose, particularly as communication systems available for voice calls tend to become more complex with time.
Collapse
Affiliation(s)
- Carolina Calderón
- UK Health Security Agency, Chemical, Radiation and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, United Kingdom.
| | - Gemma Castaño-Vinyals
- Barcelona Institute of Global Health (ISGlobal), 88 Doctor Aiguader, E-08003 Barcelona, Spain; University Pompeu Fabra, Barcelona, Spain; CIBER Epidemiologia y Salud Pública, Madrid, Spain; IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - Myron Maslanyj
- UK Health Security Agency, Chemical, Radiation and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, United Kingdom
| | - Joe Wiart
- WHIST Lab Common Lab of Orange Labs R&D and Institut Mines Telecom, Issy-les-Moulineaux, France; LTCI, Telecom Paris, Institut Polytechnique de Paris, 91120 Palaiseau, France
| | - Ae-Kyoung Lee
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon, Korea
| | - Masao Taki
- Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Electromagnetic Standards Research Center, Radio Research Institute, National Institute of Information and Communications Technology, Koganei, Japan
| | - Alex Abert
- Barcelona Institute of Global Health (ISGlobal), 88 Doctor Aiguader, E-08003 Barcelona, Spain; University Pompeu Fabra, Barcelona, Spain; CIBER Epidemiologia y Salud Pública, Madrid, Spain
| | - Francesc Badia
- Barcelona Institute of Global Health (ISGlobal), 88 Doctor Aiguader, E-08003 Barcelona, Spain; University Pompeu Fabra, Barcelona, Spain; CIBER Epidemiologia y Salud Pública, Madrid, Spain; University Autónoma de Barcelona, Spain
| | - Abdelhamid Hadjem
- WHIST Lab Common Lab of Orange Labs R&D and Institut Mines Telecom, Issy-les-Moulineaux, France
| | - Hans Kromhout
- Institute for Risk Assessment Sciences (IRAS), Utrecht University, Utrecht, the Netherlands
| | - Patricia de Llobet
- Barcelona Institute of Global Health (ISGlobal), 88 Doctor Aiguader, E-08003 Barcelona, Spain; University Pompeu Fabra, Barcelona, Spain; CIBER Epidemiologia y Salud Pública, Madrid, Spain
| | - Nadège Varsier
- WHIST Lab Common Lab of Orange Labs R&D and Institut Mines Telecom, Issy-les-Moulineaux, France
| | - Emmanuelle Conil
- WHIST Lab Common Lab of Orange Labs R&D and Institut Mines Telecom, Issy-les-Moulineaux, France; Agence Nationale des FRéquences (ANFR), Maisons-Alfort, France(1)
| | - Hyung-Do Choi
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon, Korea
| | - Malcolm R Sim
- School of Public Health and Preventive Medicine, Faculty of Medicine, Nursing and Health Science. Monash University, Alfred Centre, Commercial Road, Melbourne, Victoria 3004, Australia
| | - Elisabeth Cardis
- Barcelona Institute of Global Health (ISGlobal), 88 Doctor Aiguader, E-08003 Barcelona, Spain; University Pompeu Fabra, Barcelona, Spain; CIBER Epidemiologia y Salud Pública, Madrid, Spain
| |
Collapse
|
4
|
Chakarothai J, Wake K, Fujii K. Dosimetry of Various Human Bodies Exposed to Microwave Broadband Electromagnetic Pulses. Front Public Health 2021; 9:725310. [PMID: 34490200 PMCID: PMC8418063 DOI: 10.3389/fpubh.2021.725310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 07/21/2021] [Indexed: 11/13/2022] Open
Abstract
In this paper, human exposures to ultra-wideband (UWB) electromagnetic (EM) pulses in the microwave region are assessed using a frequency-dependent FDTD scheme previously proposed by the authors. Complex permittivity functions of all biological tissues used in the numerical analyses are accurately expressed by the four-term Cole–Cole model. In our method, we apply the fast inverse Laplace transform to determine the time-domain impulse response, utilize the Prony method to find the Z-domain representation, and extract residues and poles for use in the FDTD formulation. Update equations for the electric field are then derived via the Z-transformation. Firstly, we perform reflection and transmission analyses of a multilayer composed of six different biological tissues and then confirm the validity of the proposed method by comparison with analytical results. Finally, numerical dosimetry of various human bodies exposed to EM pulses from the front in the microwave frequency range is performed, and the specific energy absorption is evaluated and compared with that prescribed in international guidelines.
Collapse
Affiliation(s)
- Jerdvisanop Chakarothai
- Electromagnetic Compatibility Laboratory, Electromagnetic Standards Research Center, Radio Research Institute, National Institute of Information and Communications Technology, Koganei, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Electromagnetic Standards Research Center, Radio Research Institute, National Institute of Information and Communications Technology, Koganei, Japan
| | - Katsumi Fujii
- Electromagnetic Compatibility Laboratory, Electromagnetic Standards Research Center, Radio Research Institute, National Institute of Information and Communications Technology, Koganei, Japan
| |
Collapse
|
5
|
Imataka G, Wake K, Yoshihara S. A girl with acute encephalitis followed by acute cerebellitis/cerebellopathy. Eur Rev Med Pharmacol Sci 2021; 24:10708-10711. [PMID: 33155230 DOI: 10.26355/eurrev_202010_23430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
OBJECTIVE The purpose of this study is to bring attention to a case of acute encephalitis not concurrent with acute cerebellitis. CASE PRESENTATION Five days after onset of common cold symptoms, a 17-months-old girl suffered convulsions, vomiting and respiratory arrest. On exam, she had pharyngeal inflammation, brisk deep tendon reflexes, respiratory acidosis, leukocytosis, negative rapid antigen tests, and segmental pneumonia. Brain CT and MRI/MRA were negative, and EEG was consistent with acute encephalitis. Following hypothermic therapy, methylprednisolone pulse therapy and cefotaxime, she recovered. Four days after discharge, she sustained limb and truncal ataxia associated with normal EEG, followed by bilateral intention tremor. Blood and CSF chemistry and cell counts were normal. Brain MRI revealed high intensity signals in the dentate nuclei and enhancement in the cerebellar white matter, suggestive of acute cerebellitis/cerebellopathy. SPECT imaging showed reduced blood flow in the cerebellum, right thalamus and brain stem. Following short-term administration of g-globulin and prednisolone, she regained her ability to sit and, eventually, to walk. Four months after initial presentation, her brain MRI was normal. No relapse has occurred in 5 years. CONCLUSIONS The uncommon sequential development of acute encephalitis followed by acute cerebellitis suggests an immune-mediated cerebellar ataxia.
Collapse
Affiliation(s)
- G Imataka
- Department of Pediatrics, Dokkyo Medical University, Tochigi, Japan.
| | | | | |
Collapse
|
6
|
Mizuno M, Kitahara H, Sasaki K, Tani M, Kojima M, Suzuki Y, Tasaki T, Tatematsu Y, Fukunari M, Wake K. Dielectric property measurements of corneal tissues for computational dosimetry of the eye in terahertz band in vivo and in vitro. Biomed Opt Express 2021; 12:1295-1307. [PMID: 33796354 PMCID: PMC7984789 DOI: 10.1364/boe.412769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/16/2021] [Accepted: 01/27/2021] [Indexed: 05/08/2023]
Abstract
The dielectric constant of the normal corneal tissue of a rabbit eye was obtained in vitro in the range from approximately 0.1 to 1 THz, and the drying process on the eye surface exposed to high-power terahertz waves was investigated by in vivo reflectance measurement using terahertz time-domain spectroscopy. When the rabbit eye was exposed to terahertz waves at 162 GHz for 6 min with an irradiation power of 360 or 480 mW/cm2, the reflectance temporally increased and then decreased with a temperature increase. Based on multiple-reflection calculation using the dielectric constant and anterior segment optical coherence tomography images, those changes in reflectance were attributed to drying of the tear and epithelium of the cornea, respectively. Furthermore, the drying progressed over a temperature increase of around 5°C under our exposure conditions. These findings suggest that the possibility of eye damage increases with the progress of drying and that the setting of the eye surface conditions can be a cause of disagreement between computational and experimental data of absorbed energy under high-level irradiation because reflectance is related to terahertz wave penetration in the eye tissue. The time-domain spectroscopic measurements were useful for the acquisition of the dielectric constant as well as for the real-time monitoring of the eye conditions during exposure measurement.
Collapse
Affiliation(s)
- Maya Mizuno
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Hideaki Kitahara
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kensuke Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | - Masahiko Tani
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masami Kojima
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yukihisa Suzuki
- Graduate School of Systems Design, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| | - Takafumi Tasaki
- Medical Research Institute, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
- Department of Medical Zoology, Kanazawa Medical University, Kahoku, Ishikawa 920-0293, Japan
| | - Yoshinori Tatematsu
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Masafumi Fukunari
- Research Center for Development of Far-Infrared Region, University of Fukui, Fukui 910-8507, Japan
| | - Kanako Wake
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| |
Collapse
|
7
|
Nakatani-Enomoto S, Yamazaki M, Kamimura Y, Abe M, Asano K, Enomoto H, Wake K, Watanabe S, Ugawa Y. Frequency-dependent current perception threshold in healthy Japanese adults. Bioelectromagnetics 2019; 40:150-159. [PMID: 30920674 DOI: 10.1002/bem.22175] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 02/10/2019] [Indexed: 01/31/2023]
Abstract
The purpose of the study involves measuring the threshold for electric currents (i.e., current perception threshold or CPT) under several stimulating current frequencies. Specifically, current perception threshold (CPT) was measured in 53 healthy volunteers between the ages of 21 and 67. The stimulation currents were applied on the right index finger with stimulus frequencies in the range of 50 Hz - 300 kHz. The method of limits and method of constant stimuli were combined to measure the CPT. In a manner consistent with the findings obtained by previous studies, the results indicated that CPT was higher in men than in women and in older individuals than in young subjects. Bioelectromagnetics. 9999:XX-XX, 2019. © 2019 Bioelectromagnetics Society.
Collapse
Affiliation(s)
- Setsu Nakatani-Enomoto
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Madoka Yamazaki
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan.,Department of Health Science, Daito Bunka University, Saitama, Japan
| | - Yoshitsugu Kamimura
- Department of Information Science, Graduate School of Engineering, Utsunomiya University, Tochigi, Japan
| | - Mitsunari Abe
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Kohei Asano
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Hiroyuki Enomoto
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Yoshikazu Ugawa
- Department of Neurology, School of Medicine, Fukushima Medical University, Fukushima, Japan.,Fukushima Global Medical Science Center, Advanced Clinical Research Center, Fukushima Medical University, Fukushima, Japan
| |
Collapse
|
8
|
Lee AK, Park JS, Hong SE, Taki M, Wake K, Wiart J, Choi HD. Brain SAR of average male Korean child to adult models for mobile phone exposure assessment. Phys Med Biol 2019; 64:045004. [PMID: 30719982 DOI: 10.1088/1361-6560/aafcdc] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This paper aims to implement average head models of Korean males and investigate age-related differences in the brain for exposure from radiation from mobile phones. Four male head models composed of a total of 69 structures were developed through a statistical investigation of the anatomical morphology for the age groups of 6, 9, 15 and 20-24 years in age, which are named KR-6, KR-9, KR-15, and KR-22 herein. Three numerical bar phone models with a dual-band built-in antenna were applied to calculate the specific absorption rate (SAR) in the brain; the body lengths of models M avg and M long have the mean value and upper 5th percentile value of commercial bar phone models, respectively, with an antenna at the bottom, whereas M rev has an antenna on top of the phone body, which is the same as in M avg but rotated 180°. The cheek and tilt positions were employed for SAR simulations. As a result, a higher peak spatial-average SAR (psSAR) was observed in the brain for the child groups of KR-6 and KR-9 than for the adult groups of KR-15 and KR-22. In most configurations, the position-averaged psSAR10 g in the child brain was 62% (M long, 835 MHz), 61% (M avg, 835 MHz), 102% (M long, 1850 MHz), 108% (M avg, 1850 MHz), and 125% (M rev, 1850 MHz) higher than in the adult brain. The higher frequency of 1850 MHz showed a wider difference in the brain psSAR between the child and adult groups owing to the shorter penetration depth. When a long phone with an antenna at the bottom operates at a higher frequency, it significantly reduces the brain exposure.
Collapse
Affiliation(s)
- Ae-Kyoung Lee
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), Daejeon, 305-700, Republic of Korea. Author to whom any correspondence should be addressed
| | | | | | | | | | | | | |
Collapse
|
9
|
Kiyohara K, Wake K, Watanabe S, Arima T, Sato Y, Kojimahara N, Taki M, Cardis E, Yamaguchi N. Long-term recall accuracy for mobile phone calls in young Japanese people: A follow-up validation study using software-modified phones. J Expo Sci Environ Epidemiol 2018; 28:166-172. [PMID: 28000687 DOI: 10.1038/jes.2016.73] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/31/2016] [Accepted: 10/31/2016] [Indexed: 06/06/2023]
Abstract
This study examined changes in recall accuracy for mobile phone calls over a long period. Japanese students' actual call statuses were monitored for 1 month using software-modified phones (SMPs). Three face-to-face interviews were conducted to obtain information regarding self-reported call status during the monitoring period: first interview: immediately after the monitoring period; second interview: after 10-12 months; third interview: after 48-55 months. Using the SMP records as the "gold standard", phone call recall accuracy was assessed for each interview. Data for 94 participants were analyzed. The number of calls made was underestimated considerably and the duration of calls was overestimated slightly in all interviews. Agreement between self-report and SMP records regarding the number of calls, duration of calls and laterality (i.e., use of the dominant ear while making calls) gradually deteriorated with the increase in the interval following the monitoring period (number of calls: first interview: Pearson's r=0.641, third interview: 0.396; duration of calls: first interview: Pearson's r=0.763, third interview: 0.356; laterality: first interview: weighted-κ=0.677, third interview: 0.448). Thus, recall accuracy for mobile phone calls would be consistently imperfect over a long period, and the results of related epidemiological studies should be interpreted carefully.
Collapse
Affiliation(s)
- Kosuke Kiyohara
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo, Japan
| | - Takuji Arima
- Division of Advanced Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo Japan
| | - Yasuto Sato
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Noriko Kojimahara
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Masao Taki
- Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Elisabeth Cardis
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain
| | - Naohito Yamaguchi
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| |
Collapse
|
10
|
Abstract
In this study, we present an assessment of human-body exposure to an electromagnetic field at frequencies ranging from 10 GHz to 1 THz. The energy absorption and temperature elevation were assessed by solving boundary value problems of the one-dimensional Maxwell equations and a bioheat equation for a multilayer plane model. Dielectric properties were measured [Formula: see text] at frequencies of up to 1 THz at body temperature. A Monte Carlo simulation was conducted to assess variations of the transmittance into a skin surface and temperature elevation inside a body by considering the variation of the tissue thickness due to individual differences among human bodies. Furthermore, the impact of the dielectric properties of adipose tissue on temperature elevation, for which large discrepancies between our present measurement results and those in past works were observed, was also examined. We found that the dielectric properties of adipose tissue do not impact on temperature elevation at frequencies over 30 GHz. The potential risk of skin burn was discussed on the basis of the temperature elevation in millimeter-wave and terahertz-wave exposure. Furthermore, the consistency of the basic restrictions in the international guidelines set by ICNIRP was discussed.
Collapse
Affiliation(s)
- Kensuke Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | | | | | | |
Collapse
|
11
|
Calderón C, Ichikawa H, Taki M, Wake K, Addison D, Mee T, Maslanyj M, Kromhout H, Lee AK, Sim MR, Wiart J, Cardis E. ELF exposure from mobile and cordless phones for the epidemiological MOBI-Kids study. Environ Int 2017; 101:59-69. [PMID: 28126406 DOI: 10.1016/j.envint.2017.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/06/2017] [Accepted: 01/06/2017] [Indexed: 06/06/2023]
Abstract
This paper describes measurements and computational modelling carried out in the MOBI-Kids case-control study to assess the extremely low frequency (ELF) exposure of the brain from use of mobile and cordless phones. Four different communication systems were investigated: Global System for Mobile (GSM), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT) and Wi-Fi Voice over Internet Protocol (VoIP). The magnetic fields produced by the phones during transmission were measured under controlled laboratory conditions, and an equivalent loop was fitted to the data to produce three-dimensional extrapolations of the field. Computational modelling was then used to calculate the induced current density and electric field strength in the brain resulting from exposure to these magnetic fields. Human voxel phantoms of four different ages were used: 8, 11, 14 and adult. The results indicate that the current densities induced in the brain during DECT calls are likely to be an order of magnitude lower than those generated during GSM calls but over twice that during UMTS calls. The average current density during Wi-Fi VoIP calls was found to be lower than for UMTS by 30%, but the variability across the samples investigated was high. Spectral contributions were important to consider in relation to current density, particularly for DECT phones. This study suggests that the spatial distribution of the ELF induced current densities in brain tissues is determined by the physical characteristics of the phone (in particular battery position) while the amplitude is mainly dependent on communication system, thus providing a feasible basis for assessing ELF exposure in the epidemiological study. The number of phantoms was not large enough to provide definitive evidence of an increase of induced current density with age, but the data that are available suggest that, if present, the effect is likely to be very small.
Collapse
Affiliation(s)
- Carolina Calderón
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK.
| | - Hiroki Ichikawa
- Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Japan
| | - Masao Taki
- Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Japan
| | - Kanako Wake
- EMC Group, Applied Electromagnetic Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Darren Addison
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - Terry Mee
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - Myron Maslanyj
- Public Health England, Centre for Radiation, Chemical and Environmental Hazards, Chilton, Didcot, Oxon OX11 0RQ, UK
| | - Hans Kromhout
- Institute for Risk Assessment Science, Utrecht University, PO Box 80178, NL 3508 TD, Utrecht, The Netherlands
| | - Ae-Kyoung Lee
- Radio Technology Research Department, Electronics and Telecommunications Research Institute (ETRI), Yuseong-gu, Daejeon, Republic of Korea
| | - Malcolm R Sim
- Department of Epidemiology and Preventive Medicine, Faculty of Medicine, Nursing and Health Science, Monash University, Alfred Centre, Commercial Road, Melbourne, Victoria 3004, Australia
| | - Joe Wiart
- Télécom ParisTech, 37-39 Rue Dareau, 75013 Paris, France
| | - Elisabeth Cardis
- Barcelona Institute for Global Health (ISGlobal), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; CIBER Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| |
Collapse
|
12
|
Shirai T, Wang J, Kawabe M, Wake K, Watanabe SI, Takahashi S, Fujiwara O. No adverse effects detected for simultaneous whole-body exposure to multiple-frequency radiofrequency electromagnetic fields for rats in the intrauterine and pre- and post-weaning periods. J Radiat Res 2017; 58:48-58. [PMID: 27694283 PMCID: PMC5321190 DOI: 10.1093/jrr/rrw085] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 07/05/2016] [Accepted: 07/18/2016] [Indexed: 05/22/2023]
Abstract
In everyday life, people are exposed to radiofrequency (RF) electromagnetic fields (EMFs) with multiple frequencies. To evaluate the possible adverse effects of multifrequency RF EMFs, we performed an experiment in which pregnant rats and their delivered offspring were simultaneously exposed to eight different communication signal EMFs (two of 800 MHz band, two of 2 GHz band, one of 2.4 GHz band, two of 2.5 GHz band and one of 5.2 GHz band). Thirty six pregnant Sprague-Dawley (SD) 10-week-old rats were divided into three groups of 12 rats: one control (sham exposure) group and two experimental (low- and high-level RF EMF exposure) groups. The whole body of the mother rats was exposed to the RF EMFs for 20 h per day from Gestational Day 7 to weaning, and F1 offspring rats (46-48 F1 pups per group) were then exposed up to 6 weeks of age also for 20 h per day. The parameters evaluated included the growth, gestational condition and organ weights of the dams; the survival rates, development, growth, physical and functional development, memory function, and reproductive ability of the F1 offspring; and the embryotoxicity and teratogenicity in the F2 rats. No abnormal findings were observed in the dams or F1 offspring exposed to the RF EMFs or to the F2 offspring for any of the parameters evaluated. Thus, under the conditions of the present experiment, simultaneous whole-body exposure to eight different communication signal EMFs at frequencies between 800 MHz and 5.2 GHz did not show any adverse effects on pregnancy or on the development of rats.
Collapse
Affiliation(s)
- Tomoyuki Shirai
- Nagoya City Rehabilitation Center, Yatomi-cho, Mizuho-ku, Nagoya, 467-8622, Japan
- Graduate School of Medical Sciences, Nagoya City University, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Jianqing Wang
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan
| | - Mayumi Kawabe
- DIMS Institute of Medical Science, Inc., 64 Goura, Nishiazai, Azai-cho, Ichinomiya, 491-0113, Japan
| | - Kanako Wake
- National Institute of Information and Communications Technology, Nukui-Kitamachi 4-2-1, Koganei, Tokyo, 184-8705, Japan
| | - So-Ichi Watanabe
- National Institute of Information and Communications Technology, Nukui-Kitamachi 4-2-1, Koganei, Tokyo, 184-8705, Japan
| | - Satoru Takahashi
- Graduate School of Medical Sciences, Nagoya City University, Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, 467-8601, Japan
| | - Osamu Fujiwara
- Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan
| |
Collapse
|
13
|
Kiyohara K, Wake K, Watanabe S, Arima T, Sato Y, Kojimahara N, Taki M, Yamaguchi N. Recall accuracy of mobile phone calls among Japanese young people. J Expo Sci Environ Epidemiol 2016; 26:566-574. [PMID: 25783661 DOI: 10.1038/jes.2015.13] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 11/24/2014] [Accepted: 12/31/2014] [Indexed: 06/04/2023]
Abstract
This study aimed to elucidate the recall accuracy of mobile phone calls among young people using new software-modified phone (SMP) technology. A total of 198 Japanese students aged between 10 and 24 years were instructed to use a SMP for 1 month to record their actual call statuses. Ten to 12 months after this period, face-to-face interviews were conducted to obtain the self-reported call statuses during the monitoring period. Using the SMP record as the gold standard of validation, the recall accuracy of phone calls was evaluated. A total of 19% of the participants (34/177) misclassified their laterality (i.e., the dominant side of ear used while making calls), with the level of agreement being moderate (κ-statistics, 0.449). The level of agreement between the self-reports and SMP records was relatively good for the duration of calls (Pearson's r, 0.620), as compared with the number of calls (Pearson's r, 0.561). The recall was prone to small systematic and large random errors for both the number and duration of calls. Such a large random recall error for the amount of calls and misclassification of laterality suggest that the results of epidemiological studies of mobile phone use based on self-assessment should be interpreted cautiously.
Collapse
Affiliation(s)
- Kosuke Kiyohara
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Koganei, Tokyo, Japan
| | - Takuji Arima
- Division of Advanced Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Koganei-shi, Tokyo, Japan
| | - Yasuto Sato
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Noriko Kojimahara
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| | - Masao Taki
- Department of Electrical Engineering, Graduate School of Engineering, Tokyo Metropolitan University, Hachioji, Tokyo, Japan
| | - Naohito Yamaguchi
- Department of Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo, Japan
| |
Collapse
|
14
|
|
15
|
Yoshie S, Ogasawara Y, Ikehata M, Ishii K, Suzuki Y, Wada K, Wake K, Nakasono S, Taki M, Ohkubo C. Evaluation of biological effects of intermediate frequency magnetic field on differentiation of embryonic stem cell. Toxicol Rep 2016; 3:135-140. [PMID: 28959531 PMCID: PMC5615788 DOI: 10.1016/j.toxrep.2015.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 01/05/2023] Open
Abstract
The embryotoxic effect of intermediate frequency (IF) magnetic field (MF) was evaluated using murine embryonic stem (ES) cells and fibroblast cells based on the embryonic stem cell test (EST). The cells were exposed to 21 kHz IF-MF up to magnetic flux density of 3.9 mT during the cell proliferation process (7 days) or the cell differentiation process (10 days) during which an embryonic body differentiated into myocardial cells. As a result, there was no significant difference in the cell proliferation between sham- and IF-MF-exposed cells for both ES and fibroblast cells. Similarly, the ratio of the number of ES-derived cell aggregates differentiated to myocardial cells to total number of cell aggregates was not changed by IF-MF exposure. In addition, the expressions of a cardiomyocytes-specific gene, Myl2, and an early developmental gene, Hba-x, in the exposed cell aggregate were not altered. Since the magnetic flux density adopted in this study is much higher than that generated by an inverter of the electrical railway, an induction heating (IH) cooktop, etc. in our daily lives, these results suggested that IF-MF in which the public is exposed to in general living environment would not have embryotoxic effect.
Collapse
Key Words
- 5-FU, 5-fluorouracil
- Differentiation
- EB, embryonic body
- ELF, extremely low frequency
- EMF, electromagnetic field
- ES, embryonic stem
- EST, embryonic stem cell test
- Embryonic stem cell
- Gene expression
- ICNIRP, International Commission of Non-Ionizing Radiation Protection
- IF, intermediate frequency
- IH, induction heating
- Intermediate frequency magnetic field
- MF, magnetic field
- RF, radiofrequency
- WHO, World Health Organization
Collapse
Affiliation(s)
- Sachiko Yoshie
- Biotechnology Laboratory, Human Science Division, Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540, Japan
| | - Yuki Ogasawara
- Hygienic Chemistry, Health and Environmental Sciences, Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose-shi, Tokyo 204-8588, Japan
| | - Masateru Ikehata
- Biotechnology Laboratory, Human Science Division, Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540, Japan
| | - Kazuyuki Ishii
- Hygienic Chemistry, Health and Environmental Sciences, Meiji Pharmaceutical University, 2-522-1, Noshio, Kiyose-shi, Tokyo 204-8588, Japan
| | - Yukihisa Suzuki
- Faculty of Electrical & Electronic Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Keiji Wada
- Faculty of Electrical & Electronic Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, 4-2-1, Nukui-Kitamachi, Koganei, Tokyo 184-8795, Japan
| | - Satoshi Nakasono
- EMF Environment Sector, Environmental Science Research Laboratory, Central Research Institute of Electric Power Industry, 1646 Abiko, Abiko-shi, Chiba 270-1194, Japan
| | - Masao Taki
- Faculty of Electrical & Electronic Engineering, Tokyo Metropolitan University, 1-1 Minami-Osawa, Hachioji-shi, Tokyo 192-0397, Japan
| | - Chiyoji Ohkubo
- Japan EMF Information Center, 2-9-11 Shiba, Minato-ku, Tokyo 105-0014, Japan
| |
Collapse
|
16
|
Masuda H, Hirota S, Ushiyama A, Hirata A, Arima T, Kawai H, Wake K, Watanabe S, Taki M, Nagai A, Ohkubo C. No Dynamic Changes in Inflammation-related Microcirculatory Parameters in Developing Rats During Local Cortex Exposure to Microwaves. In Vivo 2015; 29:561-567. [PMID: 26359415] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The biological effects of exposing the developing brain to radiofrequency electromagnetic fields (RF) are still unclear. Our experiments investigated whether three inflammation-related, microcirculatory parameters in juvenile and young adult rats were modified during local cortex exposure to RF under non-thermal conditions. The cortex tissue was locally exposed to 1457 MHz RF at an averaged specific absorption rate of 2.0 W/kg in the target area for 50 min and variations of pial venule parameter were measured directly in vivo. There was no significant difference in hemodynamics, plasma velocity or vessel diameter, between exposed and sham-exposed groups for either rat development stage. No increase related to RF exposure was found in leukocyte adhesion to endothelial cells in any microvessels observed. These findings suggest that RF is unlikely to initiate inflammatory responses, at least under these exposure conditions.
Collapse
Affiliation(s)
- Hiroshi Masuda
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Shogo Hirota
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akira Ushiyama
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Aichi, Japan
| | - Takuji Arima
- Department of Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hiroki Kawai
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Masao Taki
- Department of Electrical and Electronic Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Akiko Nagai
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | | |
Collapse
|
17
|
Sasaki K, Isimura Y, Fujii K, Wake K, Watanabe S, Kojima M, Suga R, Hashimoto O. Dielectric property measurement of ocular tissues up to 110 GHz using 1 mm coaxial sensor. Phys Med Biol 2015; 60:6273-88. [PMID: 26237580 DOI: 10.1088/0031-9155/60/16/6273] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Measurement of the dielectric properties of ocular tissues up to 110 GHz was performed by the coaxial probe method. A coaxial sensor was fabricated to allow the measurement of small amounts of biological tissues. Four-standard calibration was applied in the dielectric property measurement to obtain more accurate data than that obtained with conventional three-standard calibration, especially at high frequencies. Novel data of the dielectric properties of several ocular tissues are presented and compared with data from the de facto database.
Collapse
Affiliation(s)
- K Sasaki
- National Institute of Information and Communications Technology, Koganei, Tokyo 184-8795, Japan
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Imataka G, Tsuboi Y, Kano Y, Ogino K, Tsuchioka T, Ohnishi T, Kaji Y, Wake K, Ichikawa G, Suzumura H, Arisaka O. Treatment with mild brain hypothermia for cardiopulmonary resuscitation after myoclonic seizures in infant with robertsonian type of trisomy 13. Eur Rev Med Pharmacol Sci 2015; 19:2852-2855. [PMID: 26241539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Congenital chromosomal abnormality with trisomy 13 is known to be associated with poor life prognosis and lethal. Therefore, physician advice the patients be kept in intensive treatment with resuscitation and state of the art intensive care when sudden change in the general condition with this trisomy is observed. We report herein, the treatment with mild brain hypothermia therapy for cardiopulmonary resuscitation after myoclonic seizures in infant with Robertsonian type of trisomy 13 in intensive care unit. Our study indicated that brain hypothermia therapy and steroid pulse therapy on an infant who was believed to have post-resuscitation hypoxic encephalopathy was highly effective as the patient's general condition recovered to the original state after four months.
Collapse
Affiliation(s)
- G Imataka
- Department of Pediatrics, Dokkyo Medical University School of Medicine, Tochigi, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
19
|
Imataka G, Wake K, Suzuki M, Yamanouchi H, Arisaka O. Acute encephalopathy associated with hemolytic uremic syndrome caused by Escherichia coli O157: H7 and rotavirus infection. Eur Rev Med Pharmacol Sci 2015; 19:1842-1844. [PMID: 26044229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We reported a case of a 22-months child with hemolytic uremic syndrome associated with encephalopathy. As the cause of this case, the involvements of verotoxin 1 and 2 caused by O157: the H7 strain of the enterohemorrhagic Escherichia coli and rotavirus were presumed. We administered brain hypothermic therapy and steroid pulse therapy in the intensive care unit, but we were not able to save his life and the child died on the 6th day from the onset.
Collapse
Affiliation(s)
- G Imataka
- Department of Pediatrics, Dokkyo Medical University School of Medicine, Tochigi, Japan.
| | | | | | | | | |
Collapse
|
20
|
Masuda H, Hirota S, Ushiyama A, Hirata A, Arima T, Kawai H, Wake K, Watanabe S, Taki M, Nagai A, Ohkubo C. No Dynamic Changes in Blood-brain Barrier Permeability Occur in Developing Rats During Local Cortex Exposure to Microwaves. In Vivo 2015; 29:351-357. [PMID: 25977380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Little information is available about the effects of exposure to radiofrequency electromagnetic fields (RF) on cerebral microcirculation during rat developmental stages. We investigated whether the permeability of the blood-brain barrier (BBB) in juvenile and young adult rats was modified during local cortex exposure to RF under non-thermal conditions. The cortex tissue targeted was locally exposed to 1457 MHz RF at an average specific absorption rate of 2.0 W/kg in the target area for 50 min and permeability changes in the BBB of the pia mater were measured directly, using intravital fluorescence microscopy. There was no significant difference in extravasation of intravenously-injected dye between exposed and sham-exposed groups of either category of rats. No histological evidence of albumin leakage was found in any of the brains just after exposure, indicating that no traces of BBB disruption remained. These findings suggest that no dynamic changes occurred in BBB permeability of the rats at either of these developmental stages, even during local RF exposure at non-thermal levels.
Collapse
Affiliation(s)
- Hiroshi Masuda
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Shogo Hirota
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akira Ushiyama
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Aichi, Japan
| | - Takuji Arima
- Department of Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hiroki Kawai
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Masao Taki
- Department of Electrical and Electronic Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Akiko Nagai
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | | |
Collapse
|
21
|
Masuda H, Hirota S, Ushiyama A, Hirata A, Arima T, Watanabe H, Wake K, Watanabe S, Taki M, Nagai A, Ohkubo C. No changes in cerebral microcirculatory parameters in rat during local cortex exposure to microwaves. In Vivo 2015; 29:207-215. [PMID: 25792647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The aim of this study was to determine whether cerebral microcirculatory parameters in rats were modified during local cortex exposure to a radiofrequency electromagnetic field (RF) under non-thermal conditions. The cortex tissue targeted was locally exposed to 1439 MHz RF using a figure-8 loop antenna at an averaged specific absorption rate of 2.0 W/kg in the target area for 50 min. Three microcirculatory parameters related to cerebral inflammation were measured by the cranial window method in real-time under RF exposure. No extravasation of intravenously injected fluorescent dye was observed during RF exposure. There was no significant difference either in pial venule blood flow velocity or diameter between exposed and sham-exposed rats. Histological evaluation for the brain immediately after RF exposure did not reveal any serum albumin leakage sites or degenerate neurons. These findings suggest that no dynamic changes occurred in cerebral microcirculation even during local cortex exposure under these conditions.
Collapse
Affiliation(s)
- Hiroshi Masuda
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Shogo Hirota
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akira Ushiyama
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan
| | - Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Aichi, Japan
| | - Takuji Arima
- Department of Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hiroshi Watanabe
- Department of Electrical and Electronics Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Laboratory, Applied Electromagnetic Research Institute, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Masao Taki
- Department of Electrical and Electronic Engineering, Tokyo Metropolitan University, Tokyo, Japan
| | - Akiko Nagai
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University, Tokyo, Japan
| | - Chiyoji Ohkubo
- Department of Environmental Health, National Institute of Public Health, Saitama, Japan Japan EMF Information Center, Tokyo, Japan
| |
Collapse
|
22
|
Shirai T, Imai N, Wang J, Takahashi S, Kawabe M, Wake K, Kawai H, Watanabe SI, Furukawa F, Fujiwara O. Multigenerational effects of whole body exposure to 2.14 GHz W-CDMA cellular phone signals on brain function in rats. Bioelectromagnetics 2014; 35:497-511. [DOI: 10.1002/bem.21871] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Accepted: 06/26/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Tomoyuki Shirai
- Department of Experimental Pathology and Tumor Biology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Norio Imai
- DIMS Institute of Medical Science; Ichinomiya; Aichi Japan
| | - Jianqing Wang
- Department of Computer Science and Engineering; Graduate School of Engineering; Nagoya Institute of Technology; Nagoya Japan
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology; Nagoya City University Graduate School of Medical Sciences; Nagoya Japan
| | - Mayumi Kawabe
- DIMS Institute of Medical Science; Ichinomiya; Aichi Japan
| | - Kanako Wake
- Electromagnetic Compatibility Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - Hiroki Kawai
- Electromagnetic Compatibility Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - So-Ichi Watanabe
- Electromagnetic Compatibility Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - Fumio Furukawa
- DIMS Institute of Medical Science; Ichinomiya; Aichi Japan
| | - Osamu Fujiwara
- Department of Computer Science and Engineering; Graduate School of Engineering; Nagoya Institute of Technology; Nagoya Japan
| |
Collapse
|
23
|
Sasaki K, Wake K, Watanabe S. Measurement of the dielectric properties of the epidermis and dermis at frequencies from 0.5 GHz to 110 GHz. Phys Med Biol 2014; 59:4739-47. [DOI: 10.1088/0031-9155/59/16/4739] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
24
|
Imataka G, Wake K, Yamanouchi H, Ono K, Arisaka O. Brain hypothermia therapy for status epilepticus in childhood. Eur Rev Med Pharmacol Sci 2014; 18:1883-1888. [PMID: 25010618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
OBJECTIVE At the Dokkyo Medical University Hospital, we introduced a brain hypothermia therapy protocol for treating childhood status epilepticus and acute encephalitis/encephalopathy in 2004. PATIENTS AND METHODS This protocol focuses on infants with a minimum age of six months or 7.5 kg in weight. Applicable diseases include acute encephalitis/encephalopathy occurring from status epilepticus or seizures lasting for 30 minutes or longer, in cases such as near drowning, hypoxic-ischemic encephalopathy, post-resuscitation encephalopathy, cardio-respiratory arrest, severe head injury, or other diagnoses in which the pediatric neurologist recognizes the possibility of neurological complications. Brain hypothermia therapy is managed within the intensive care unit (ICU). RESULTS The target body temperature is a bladder or rectum temperature of 34.0 to 35.0 degrees. This body temperature is reduced to the target temperature within six hours of the seizures. Hypothermia is maintained for 48 hours and concomitant steroid pulse therapy may be used at appropriate times. Sodium thiopental is used to sedate and rewarming is carried out at 0.5 degrees per 12 hours. Osmotic diuretics, muscle relaxants and circulatory antagonists may be concomitantly used at appropriate times. CONCLUSIONS This paper reviews the brain hypothermia therapy protocol.
Collapse
Affiliation(s)
- G Imataka
- Department of Pediatrics; Dokkyo Medical University School of Medicine, Tochigi, Japan.
| | | | | | | | | |
Collapse
|
25
|
Nakatani-Enomoto S, Furubayashi T, Ushiyama A, Groiss SJ, Ueshima K, Sokejima S, Simba AY, Wake K, Watanabe SI, Nishikawa M, Miyawaki K, Taki M, Ugawa Y. Effects of electromagnetic fields emitted from W-CDMA-like mobile phones on sleep in humans. Bioelectromagnetics 2013; 34:589-98. [DOI: 10.1002/bem.21809] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 07/06/2013] [Indexed: 11/08/2022]
Affiliation(s)
- Setsu Nakatani-Enomoto
- Department of Neurology; School of Medicine; Fukushima Medical University; Fukushima Japan
| | - Toshiaki Furubayashi
- Department of Neurology; School of Medicine; Fukushima Medical University; Fukushima Japan
- Department of Health and Social Services; Tohoku Bunka Gakuen University; Miyagi Japan
| | - Akira Ushiyama
- Department of Environmental Health; National Institute of Public Health; Saitama Japan
| | - Stefan Jun Groiss
- Department of Neurology; School of Medicine; Fukushima Medical University; Fukushima Japan
| | - Kazumune Ueshima
- Department of Public Health and Occupational Medicine; Mie University Graduate School of Medicine; Mie Japan
| | - Shigeru Sokejima
- Department of Public Health and Occupational Medicine; Mie University Graduate School of Medicine; Mie Japan
| | - Ally Y. Simba
- EMC Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - Kanako Wake
- EMC Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - So-ichi Watanabe
- EMC Group; Applied Electromagnetic Research Center; National Institute of Information and Communications Technology; Tokyo Japan
| | - Masami Nishikawa
- Department of Education; Kawamura Gakuen Woman's University; Chiba Japan
| | - Kaori Miyawaki
- Faculty of Letters; Arts and Sciences; Waseda University; Tokyo Japan
| | - Masao Taki
- Department of Electrical and Electronic Engineering; Graduate School of Science and Engineering; Tokyo Metropolitan University; Tokyo Japan
| | - Yoshikazu Ugawa
- Department of Neurology; School of Medicine; Fukushima Medical University; Fukushima Japan
- Japan Science and Technology Agency; Research Seeds Quest Program; Fukushima Japan
| |
Collapse
|
26
|
Sasaki K, Segawa H, Mizuno M, Wake K, Watanabe S, Hashimoto O. Development of the complex permittivity measurement system for high-loss biological samples using the free space method in quasi-millimeter and millimeter wave bands. Phys Med Biol 2013; 58:1625-33. [DOI: 10.1088/0031-9155/58/5/1625] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
27
|
Wang J, Wake K, Kawai H, Watanabe S, Fujiwara O. Statistical determination of whole-body average SARs in a 2 GHz whole-body exposure system for unrestrained pregnant and newborn rats. Phys Med Biol 2011; 57:143-54. [PMID: 22127341 DOI: 10.1088/0031-9155/57/1/143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A 2 GHz whole-body exposure to rats over a multigeneration has been conducted as part of bio-effect research in Japan. In this study, the rats moved freely in the cage inside the exposure system. From observation of the activity of rats in the cage, we found that the rats do not stay in each position with uniform possibility. In order to determine the specific absorption rate (SAR) during the entire exposure period with high accuracy, we present a new approach to statistically determine the SAR level in an exposure system. First, we divided the rat cage in the exposure system into several small areas, and derived the fraction of time the rats spent in each small area based on the classification of the documentary photos of rat activity. Then, using the fraction of time spent in each small area as a weighting factor, we calculated the statistical characteristics of the whole-body average SAR for pregnant rats and young rats during the entire exposure period. As a result, this approach gave the statistical distribution as well as the corresponding mean value, median value and mode value for the whole-body SAR so that we can reasonably clarify the relationship between the exposure level and possible biological effect.
Collapse
Affiliation(s)
- Jianqing Wang
- Department of Computer Science and Engineering, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan.
| | | | | | | | | |
Collapse
|
28
|
Deltour I, Wiart J, Taki M, Wake K, Varsier N, Mann S, Schüz J, Cardis E. Analysis of three-dimensional SAR distributions emitted by mobile phones in an epidemiological perspective. Bioelectromagnetics 2011; 32:634-43. [PMID: 21695709 DOI: 10.1002/bem.20684] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 05/20/2011] [Indexed: 11/10/2022]
Abstract
The three-dimensional distribution of the specific absorption rate of energy (SAR) in phantom models was analysed to detect clusters of mobile phones producing similar spatial deposition of energy in the head. The clusters' characteristics were described from the phones external features, frequency band and communication protocol. Compliance measurements with phones in cheek and tilt positions, and on the left and right side of a physical phantom were used. Phones used the Personal Digital Cellular (PDC), Code division multiple access One (CdmaOne), Global System for Mobile Communications (GSM) and Nordic Mobile Telephony (NMT) communication systems, in the 800, 900, 1500 and 1800 MHz bands. Each phone's measurements were summarised by the half-ellipsoid in which the SAR values were above half the maximum value. Cluster analysis used the Partitioning Around Medoids algorithm. The dissimilarity measure was based on the overlap of the ellipsoids, and the Manhattan distance was used for robustness analysis. Within the 800 MHz frequency band, and in part within the 900 MHz and the 1800 MHz frequency bands, weak clustering was obtained for the handset shape (bar phone, flip with top and flip with central antennas), but only in specific positions (tilt or cheek). On measurements of 120 phones, the three-dimensional distribution of SAR in phantom models did not appear to be related to particular external phone characteristics or measurement characteristics, which could be used for refining the assessment of exposure to radiofrequency energy within the brain in epidemiological studies such as the Interphone.
Collapse
Affiliation(s)
- Isabelle Deltour
- Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark; International Agency for Research on Cancer, Lyon, France.
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Cardis E, Varsier N, Bowman JD, Deltour I, Figuerola J, Mann S, Moissonnier M, Taki M, Vecchia P, Villegas R, Vrijheid M, Wake K, Wiart J. Estimation of RF energy absorbed in the brain from mobile phones in the Interphone Study. Occup Environ Med 2011; 68:686-93. [PMID: 21659468 PMCID: PMC3158331 DOI: 10.1136/oemed-2011-100065] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Objectives The objective of this study was to develop an estimate of a radio frequency (RF) dose as the amount of mobile phone RF energy absorbed at the location of a brain tumour, for use in the Interphone Epidemiological Study. Methods We systematically evaluated and quantified all the main parameters thought to influence the amount of specific RF energy absorbed in the brain from mobile telephone use. For this, we identified the likely important determinants of RF specific energy absorption rate during protocol and questionnaire design, we collected information from study subjects, network operators and laboratories involved in specific energy absorption rate measurements and we studied potential modifiers of phone output through the use of software-modified phones. Data collected were analysed to assess the relative importance of the different factors, leading to the development of an algorithm to evaluate the total cumulative specific RF energy (in joules per kilogram), or dose, absorbed at a particular location in the brain. This algorithm was applied to Interphone Study subjects in five countries. Results The main determinants of total cumulative specific RF energy from mobile phones were communication system and frequency band, location in the brain and amount and duration of mobile phone use. Though there was substantial agreement between categorisation of subjects by cumulative specific RF energy and cumulative call time, misclassification was non-negligible, particularly at higher frequency bands. Factors such as adaptive power control (except in Code Division Multiple Access networks), discontinuous transmission and conditions of phone use were found to have a relatively minor influence on total cumulative specific RF energy. Conclusions While amount and duration of use are important determinants of RF dose in the brain, their impact can be substantially modified by communication system, frequency band and location in the brain. It is important to take these into account in analyses of risk of brain tumours from RF exposure from mobile phones.
Collapse
Affiliation(s)
- E Cardis
- Centre for Research in Environmental Epidemiology (CREAL), Hospital del Mar Research Institute (IMIM), CIBER Epidemiologia y Salud PÃblica (CIBERESP), Doctor Aiguader 88, 08003 Barcelona, Spain.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Yamashita H, Hata K, Yamaguchi H, Tsurita G, Wake K, Watanabe S, Taki M, Ueno S, Nagawa H. Short-term exposure to a 1439-MHz TDMA signal exerts no estrogenic effect in rats. Bioelectromagnetics 2011; 31:573-5. [PMID: 20607740 DOI: 10.1002/bem.20593] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The aim of this study was to elucidate the possible effects of short-term exposure to a 1439-MHz electromagnetic field (EMF) employing time division multiple access (TDMA), which is the basis of the Japanese Personal Digital Cellular system, on estrogenic activity in rats. Sixty-four ovariectomized female Sprague-Dawley rats were divided into four groups: EMF exposure (EM), sham exposure, cage control, and 17 beta-estradiol injected (E2). The EM group was exposed, for 4 h per day on three consecutive days, to the 1439-MHz TDMA signal that produced 5.5-6.1 and 0.88-0.99 W/kg average specific absorption rates in the brain and the whole body, respectively. The uterine wet mass and serum estradiol level significantly increased in the E2 group, while there were no differences among the other three groups. Although negative effects of long-term EMF exposure must be thoroughly investigated before a final conclusion can be reached, our results do not support the assumption that the high frequency EMF used in cellular phones exerts estrogenic activity.
Collapse
Affiliation(s)
- Hiroharu Yamashita
- Department of Surgical Oncology, The University of Tokyo, Graduate School of Medicine, Tokyo, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Arima T, Watanabe H, Wake K, Masuda H, Watanabe S, Taki M, Uno T. Local exposure system for rats head using a figure-8 loop antenna in 1500-MHz band. IEEE Trans Biomed Eng 2011; 58:2740-7. [PMID: 21216701 DOI: 10.1109/tbme.2010.2103942] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cellular phones are used in the vicinity of the human head, resulting in localized exposure to this part of the body. To simulate exposure during cellular phone use, microwave energy absorption should be focused within the head region of laboratory animals. In this paper, we developed an exposure system using a figure-8 loop antenna to permit localized exposure of a rat head to 1500-MHz microwave fields, simulating human head exposure to cellular phones. We have numerically estimated the specific absorption rate (SAR) in a rat exposed to microwave fields via our new exposure system. The high ratio of SAR averaged over the target tissue (i.e., the brain) to that averaged over the whole body suggests that the figure-8 antenna can realize greater localized exposure than the previously used exposure system. We have also confirmed the effectiveness of our proposed system experimentally.
Collapse
Affiliation(s)
- Takuji Arima
- National Institute of Information and Communications Technology, Tokyo 184-8795, Japan.
| | | | | | | | | | | | | |
Collapse
|
32
|
Masuda H, Hirata A, Kawai H, Wake K, Watanabe S, Arima T, Poulletier de Gannes F, Lagroye I, Veyret B. Local exposure of the rat cortex to radiofrequency electromagnetic fields increases local cerebral blood flow along with temperature. J Appl Physiol (1985) 2011; 110:142-8. [DOI: 10.1152/japplphysiol.01035.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Few studies have shown that local exposure to radiofrequency electromagnetic fields (RF) induces intensity-dependent physiological changes, especially in the brain. The aim of the present study was to detect reproducible responses to local RF exposure in the parietal cortex of anesthetized rats and to determine their dependence on RF intensity. The target cortex tissue was locally exposed to 2-GHz RF using a figure-eight loop antenna within a range of averaged specific absorption rates (10.5, 40.3, 130, and 263 W/kg averaged over 4.04 mg) in the target area. Local cerebral blood flow (CBF) and temperatures in three regions (target area, rectum, and calf hypodermis) were measured using optical fiber blood flow meters and thermometers during RF exposure. All parameters except for the calf hypodermis temperature increased significantly in exposed animals compared with sham-exposed ones during 18-min exposures. Dependence of parameter values on exposure intensity was analyzed using linear regression models. The elevation of local CBF was correlated with temperature rise in both target and rectum at the end of RF exposure. However, the local CBF elevation seemed to be elevated by the rise in target temperature, but not by that of the rectal temperature, in the early part of RF exposure or at low-intensity RF exposure. These findings suggest that local RF exposure of the rat cortex drives a regulation of CBF accompanied by a local temperature rise, and our findings may be helpful for discussing physiological changes in the local cortex region, which is locally exposed to RF.
Collapse
Affiliation(s)
- Hiroshi Masuda
- University of Bordeaux, IMS Laboratory, Pessac cedex, France
| | - Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Aichi, Japan
| | - Hiroki Kawai
- Electromagnetic Compatibility Group, Applied Electromagnetic Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Kanako Wake
- Electromagnetic Compatibility Group, Applied Electromagnetic Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Soichi Watanabe
- Electromagnetic Compatibility Group, Applied Electromagnetic Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
| | - Takuji Arima
- Electromagnetic Compatibility Group, Applied Electromagnetic Research Center, National Institute of Information and Communications Technology, Tokyo, Japan
- Department of Electrical and Electronics Engineering of Tokyo University of Agriculture and Technology, Tokyo, Japan; and
| | | | - Isabelle Lagroye
- University of Bordeaux, IMS Laboratory, Pessac cedex, France
- Bioelectromagnetics Laboratory, École Pratique des Hautes Études, Pessac cedex, France
| | - Bernard Veyret
- University of Bordeaux, IMS Laboratory, Pessac cedex, France
- Bioelectromagnetics Laboratory, École Pratique des Hautes Études, Pessac cedex, France
| |
Collapse
|
33
|
Takahashi S, Imai N, Nabae K, Wake K, Kawai H, Wang J, Watanabe SI, Kawabe M, Fujiwara O, Ogawa K, Tamano S, Shirai T. Lack of Adverse Effects of Whole-Body Exposure to a Mobile Telecommunication Electromagnetic Field on the Rat Fetus. Radiat Res 2010; 173:362-72. [DOI: 10.1667/rr1615.1] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
34
|
Hirata A, Yamazaki K, Hamada S, Kamimura Y, Tarao H, Wake K, Suzuki Y, Hayashi N, Fujiwara O. Intercomparison of induced fields in Japanese male model for ELF magnetic field exposures: effect of different computational methods and codes. Radiat Prot Dosimetry 2010; 138:237-244. [PMID: 19933697 DOI: 10.1093/rpd/ncp251] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The present study provides an intercomparison of the induced quantities in a human model for uniform magnetic field exposures at extremely low frequency. A total of six research groups have cooperated in this joint intercomparison study. The computational conditions and numeric human phantom including the conductivity of tissue were set identically to focus on the uncertainty in computed fields. Differences in the maximal and 99th percentile value of the in situ electric field were less than 30 and 10 % except for the results of one group. Differences in the current density averaged over 1 cm(2) of the central nerve tissue are 10 % or less except for the results of one group. This comparison suggests that the computational uncertainty of the in situ electric field/current density due to different methods and coding is smaller than that caused by different human phantoms and the conductivitys of tissue, which was reported in a previous study.
Collapse
Affiliation(s)
- Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Mitsui Y, Arichi N, Hiraki M, Wake K, Hiraoka T, Sumura M, Honda S, Yasumoto H, Shiina H, Igawa M. UP-1.128: Longitudinal Alteration of Neuroendocrine Differentiation in Prostate Cancer Tissue-Application to Chemo-Sensitivity. Urology 2009. [DOI: 10.1016/j.urology.2009.07.575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
36
|
Arichi N, Mitsui Y, Sumura M, Inoue S, Wake K, Hiraoka T, Honda S, Yasumoto H, Shiina H, Igawa M. MP-21.09: Combination of Diffusion-Weighted Imaging (DWI) and Ultrasound Real-Time Tissue Elastography (RTE) can Eliminate the Necessity of Dynamic Contrast-Enhanced (DCE) MRI in the Detection of Prostate Cancer. Urology 2009. [DOI: 10.1016/j.urology.2009.07.753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
37
|
Hirata A, Wake K, Watanabe S, Taki M. In-situ electric field and current density in Japanese male and female models for uniform magnetic field exposures. Radiat Prot Dosimetry 2009; 135:272-275. [PMID: 19628703 DOI: 10.1093/rpd/ncp117] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The present study quantified the in situ electric field and induced current density in anatomically based numeric Japanese male and female models for exposure to extremely low-frequency magnetic fields. A quasi-static FDTD method was applied to analyse this problem. The computational results obtained herein reveal that the 99 th percentile value of the in situ electric field in the nerve tissue and the current density averaged over an area of 1 cm(2) of the nerve tissue (excluding non-nerve tissues in the averaging region) in the female models were less than 35 and 25 %, respectively. These induced quantities in the Japanese models were smaller than those for European models reported in a previous study, which is mainly due to the difference in cross-sectional area of the body.
Collapse
Affiliation(s)
- Akimasa Hirata
- National Institute of Information and Communications Technology, EMC group, Tokyo, Japan.
| | | | | | | |
Collapse
|
38
|
Ogawa K, Nabae K, Wang J, Wake K, Watanabe SI, Kawabe M, Fujiwara O, Takahashi S, Ichihara T, Tamano S, Shirai T. Effects of gestational exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular phones: Lack of embryotoxicity and teratogenicity in rats. Bioelectromagnetics 2009; 30:205-12. [DOI: 10.1002/bem.20456] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
39
|
Furubayashi T, Ushiyama A, Terao Y, Mizuno Y, Shirasawa K, Pongpaibool P, Simba AY, Wake K, Nishikawa M, Miyawaki K, Yasuda A, Uchiyama M, Yamashita HK, Masuda H, Hirota S, Takahashi M, Okano T, Inomata-Terada S, Sokejima S, Maruyama E, Watanabe S, Taki M, Ohkubo C, Ugawa Y. Effects of short-term W-CDMA mobile phone base station exposure on women with or without mobile phone related symptoms. Bioelectromagnetics 2009; 30:100-13. [DOI: 10.1002/bem.20446] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
40
|
Hirota S, Matsuura M, Masuda H, Ushiyama A, Wake K, Watanabe S, Taki M, Ohkubo C. Direct observation of microcirculatory parameters in rat brain after local exposure to radio-frequency electromagnetic field. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s10669-008-9199-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
41
|
Cardis E, Deltour I, Mann S, Moissonnier M, Taki M, Varsier N, Wake K, Wiart J. Distribution of RF energy emitted by mobile phones in anatomical structures of the brain. Phys Med Biol 2008; 53:2771-83. [PMID: 18451464 DOI: 10.1088/0031-9155/53/11/001] [Citation(s) in RCA: 129] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The rapid worldwide increase in mobile phone use in the last decade has generated considerable interest in possible carcinogenic effects of radio frequency (RF). Because exposure to RF from phones is localized, if a risk exists it is likely to be greatest for tumours in regions with greatest energy absorption. The objective of the current paper was to characterize the spatial distribution of RF energy in the brain, using results of measurements made in two laboratories on 110 phones used in Europe or Japan. Most (97-99% depending on frequency) appears to be absorbed in the brain hemisphere on the side where the phone is used, mainly (50-60%) in the temporal lobe. The average relative SAR is highest in the temporal lobe (6-15%, depending on frequency, of the spatial peak SAR in the most exposed region of the brain) and the cerebellum (2-10%) and decreases very rapidly with increasing depth, particularly at higher frequencies. The SAR distribution appears to be fairly similar across phone models, between older and newer phones and between phones with different antenna types and positions. Analyses of risk by location of tumour are therefore important for the interpretation of results of studies of brain tumours in relation to mobile phone use.
Collapse
Affiliation(s)
- E Cardis
- Radiation Group, International Agency for Research on Cancer, 150 cours Albert Thomas, Lyon 69372, France
| | | | | | | | | | | | | | | |
Collapse
|
42
|
Takebayashi T, Varsier N, Kikuchi Y, Wake K, Taki M, Watanabe S, Akiba S, Yamaguchi N. Mobile phone use, exposure to radiofrequency electromagnetic field, and brain tumour: a case-control study. Br J Cancer 2008; 98:652-9. [PMID: 18256587 PMCID: PMC2243154 DOI: 10.1038/sj.bjc.6604214] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
In a case–control study in Japan of brain tumours in relation to mobile phone use, we used a novel approach for estimating the specific absorption rate (SAR) inside the tumour, taking account of spatial relationships between tumour localisation and intracranial radiofrequency distribution. Personal interviews were carried out with 88 patients with glioma, 132 with meningioma, and 102 with pituitary adenoma (322 cases in total), and with 683 individually matched controls. All maximal SAR values were below 0.1 W kg−1, far lower than the level at which thermal effects may occur, the adjusted odds ratios (ORs) for regular mobile phone users being 1.22 (95% confidence interval (CI): 0.63–2.37) for glioma and 0.70 (0.42–1.16) for meningioma. When the maximal SAR value inside the tumour tissue was accounted for in the exposure indices, the overall OR was again not increased and there was no significant trend towards an increasing OR in relation to SAR-derived exposure indices. A non-significant increase in OR among glioma patients in the heavily exposed group may reflect recall bias.
Collapse
Affiliation(s)
- T Takebayashi
- Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Ushiyama A, Masuda H, Hirota S, Wake K, Kawai H, Watanabe S, Taki M, Ohkubo C. Biological effect on blood cerebrospinal fluid barrier due to radio frequency electromagnetic fields exposure of the rat brain in vivo. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s10669-007-9070-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
44
|
Masuda H, Ushiyama A, Hirota S, Wake K, Watanabe S, Yamanaka Y, Taki M, Ohkubo C. Effects of subchronic exposure to a 1439 MHz electromagnetic field on the microcirculatory parameters in rat brain. In Vivo 2007; 21:563-70. [PMID: 17708347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
UNLABELLED THE AIM of this study was to investigate whether repeated exposure to radio frequency electromagnetic field (RF-EMF) of 1439 MHz affects the cerebral microcirculation, including blood-brain barrier function, in a rat brain. MATERIALS AND METHODS The head of the rat was exposed for four weeks (60 min/day, 5 days/week) to RF-EMF at 2.4 W/kg of brain averaged specific absorption rate (BASAR). Three microcirculatory parameters: blood-brain barrier permeability, leukocyte behavior and plasma velocity were measured before and after RF-EMF exposure using a closed cranial window method. RESULTS No extravasation of intravenously injected dyes from pial venules was found at any BASAR level. No significant changes in the number of endothelial-adhering leukocytes after exposure were found. The plasma velocity remained constant within the physiological range through each exposure. CONCLUSION These findings suggest that there were no effects on the cerebral microcirculation under the given RF-EMF exposure conditions.
Collapse
Affiliation(s)
- Hiroshi Masuda
- Department of Environmental Health, National Institute of Public Health, Wako-shi, Saitama, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Masuda H, Ushiyama A, Hirota S, Wake K, Watanabe S, Yamanaka Y, Taki M, Ohkubo C. Effects of acute exposure to a 1439 MHz electromagnetic field on the microcirculatory parameters in rat brain. In Vivo 2007; 21:555-62. [PMID: 17708346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
UNLABELLED THE AIM of this study was to determine the potential of radio-frequency electromagnetic fields (RF-EMF) to affect cerebral microcirculation, including blood-brain barrier function, in rat brain. MATERIALS AND METHODS The head of the rat was exposed for 10 min to 1439 MHz RF-EMF having three intensity doses: 0.6, 2.4, 4.8 W/kg of brain averaged specific absorption rate (BASAR). Four microcirculatory parameters: blood-brain barrier permeability, leukocyte behavior, plasma velocity, and vessel diameter were measured before and after RF-EMF exposure using a closed cranial window method. RESULTS No extravasation of intravenously injected dyes from pial venules was found at any BASAR level. No significant changes in the number of endothelial-adhering leukocytes after exposure were found. The hemodynamics indicated that the plasma velocities and vessel diameters remained constant within the physiological range throughout each exposure. CONCLUSION These findings suggest that there were no effects on the cerebral microcirculation under the given RF-EMF exposure conditions.
Collapse
Affiliation(s)
- Hiroshi Masuda
- Department of Environmental Health, National Institute of Public Health, Wako-shi, Saitama, Japan.
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Shirai T, Ichihara T, Wake K, Watanabe SI, Yamanaka Y, Kawabe M, Taki M, Fujiwara O, Wang J, Takahashi S, Tamano S. Lack of promoting effects of chronic exposure to 1.95-GHz W-CDMA signals for IMT-2000 cellular system on development of N-ethylnitrosourea-induced central nervous system tumors in F344 rats. Bioelectromagnetics 2007; 28:562-72. [PMID: 17516507 DOI: 10.1002/bem.20324] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The present study was performed to evaluate effects of a 2-year exposure to an electromagnetic near-field (EMF) equivalent to that generated by cellular phones on tumor development in the central nervous system (CNS) of rats. For this purpose, pregnant F344 rats were given a single administration of N-ethylnitrosourea (ENU) on gestational day 18. A total of 500 pups were divided into five groups, each composed of 50 males and 50 females: Group 1, untreated controls; Group 2, ENU alone; Groups 3 to 5, ENU + EMF (sham exposure and two exposure levels). A 1.95-GHz wide-band code division multiple access (W-CDMA) signal, which is a feature of the International Mobile Telecommunication 2000 (IMT-2000) cellular system was employed for exposure of the rat head starting from 5 weeks of age, 90 min a day, 5 days a week, for 104 weeks. Brain average specific absorption rates (SARs) were designed to be .67 and 2.0 W/kg for low and high exposures, respectively. The incidence and numbers of brain tumors in female rats exposed to 1.95-GHz W-CDMA signals showed tendencies to increase but without statistical significance. Overall, no significant increase in incidences or numbers, either in the males or females, was detected in the EMF-exposed groups. In addition, no clear changes in tumor types in the brain were evident. Thus, under the present experimental conditions, exposure of heads of rats to 1.95-GHz W-CDMA signals for IMT-2000 for a 2-year period was not demonstrated to accelerate or otherwise affect ENU-initiated brain tumorigenesis.
Collapse
Affiliation(s)
- Tomoyuki Shirai
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Abstract
OBJECTIVES The rapid increase of mobile phone use has increased public concern about its possible health effects in Japan, where the mobile phone system is unique in the characteristics of its signal transmission. To examine the relation between mobile phone use and acoustic neuroma, a case-control study was initiated. METHODS The study followed the common, core protocol of the international collaborative study, INTERPHONE. A prospective case recruitment was done in Japan for 2000-04. One hundred and one acoustic neuroma cases, who were 30-69 years of age and resided in the Tokyo area, and 339 age, sex, and residency matched controls were interviewed using a common computer assisted personal interview system. Education and marital status adjusted odds ratio was calculated with a conditional logistic regression analysis. RESULTS Fifty one cases (52.6%) and 192 controls (58.2%) were regular mobile phone users on the reference date, which was set as one year before the diagnosis, and no significant increase of acoustic neuroma risk was observed, with the odds ratio (OR) being 0.73 (95% CI 0.43 to 1.23). No exposure related increase in the risk of acoustic neuroma was observed when the cumulative length of use (<4 years, 4-8 years, >8 years) or cumulative call time (<300 hours, 300-900 hours, >900 hours) was used as an exposure index. The OR was 1.09 (95% CI 0.58 to 2.06) when the reference date was set as five years before the diagnosis. Further, laterality of mobile phone use was not associated with tumours. CONCLUSIONS These results suggest that there is no significant increase in the risk of acoustic neuroma in association with mobile phone use in Japan.
Collapse
Affiliation(s)
- T Takebayashi
- Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan
| | | | | | | | | | | | | |
Collapse
|
48
|
Miyamoto K, Mitsui M, Katashio H, Wake K, Imataka G, Yamnouchi H, Eguchi M. [Case of theophylline-induced seizures successfully treated with mild hypothermic therapy and methylpredonisolone pulse therapy]. No To Hattatsu 2006; 38:219-20. [PMID: 16715938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
|
49
|
Hirata A, Watanabe S, Kojima M, Hata I, Wake K, Taki M, Sasaki K, Fujiwara O, Shiozawa T. Computational verification of anesthesia effect on temperature variations in rabbit eyes exposed to 2.45 GHz microwave energy. Bioelectromagnetics 2006; 27:602-12. [PMID: 16724330 DOI: 10.1002/bem.20251] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This paper computationally verifies the effect of anesthesia on temperature variations in the rabbit eye due to microwave energy. The main reason for this investigation is that our previous paper suggested a reduction in blood flow due to the administration of anesthesia, resulting in an overestimated temperature increase. However, no quantitative investigation has yet been conducted. The finite-difference time-domain (FDTD) method is used for calculating power absorption and temperature variation in rabbits. For this purpose, we used a computational rabbit phantom, which is comprised of 12 tissues (including 6 eye tissues) with a resolution of 1 mm. Thermal constants of the rabbit were derived by comparing measured and calculated temperatures. For intense microwave exposure to the rabbit eye, time courses of calculated and measured temperatures were in good agreement for cases both with and without the administration of anesthesia. The point to be stressed is that under anesthesia the thermoregulatory response was inactivated and blood flow and basal metabolism was reduced.
Collapse
Affiliation(s)
- Akimasa Hirata
- Department of Computer Science and Engineering, Nagoya Institute of Technology, Nagoya, Japan.
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Shirai T, Kawabe M, Ichihara T, Fujiwara O, Taki M, Watanabe SI, Wake K, Yamanaka Y, Imaida K, Asamoto M, Tamano S. Chronic exposure to a 1.439 GHz electromagnetic field used for cellular phones does not promote N-ethylnitrosourea induced central nervous system tumors in F344 rats. Bioelectromagnetics 2004; 26:59-68. [PMID: 15605402 DOI: 10.1002/bem.20079] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The present study was designed to evaluate whether a 2 year exposure to an electromagnetic field (EMF) equivalent to that generated by cellular phones can accelerate tumor development in the central nervous system (CNS) of rats. Brain tumorigenesis was initiated by an intrauterine exposure to N-ethylnitrosourea (ENU) on gestational day 18. A total of 500 pups were divided into five groups, each composed of 50 males and 50 females: Group 1, untreated control; Group 2, ENU alone; Groups 3-5, ENU + EMF (sham exposure and 2 exposure levels). A 1.439 GHz time division multiple access (TDMA) signal for the Personal Digital Cellular (PDC), Japanese standard cellular system was used for the exposure of the rat head starting from 5 weeks of age, 90 min a day, 5 days a week, for 104 weeks. Brain average specific absorption rate (SAR) was 0.67 and 2.0 W/kg for low and high exposures, respectively: whole body average SAR was less than 0.4 W/kg. There were no inter-group differences in body weights, food consumption, and survival rates. No increase in the incidences or numbers per group of brain and/or spinal cord tumors, either in the males or females, was detected in the EMF exposed groups. In addition, no clear changes in tumor types were evident. Thus, under the present experimental conditions, 1.439 GHz EMF exposure to the heads of rats for a 2 year period was not demonstrated to accelerate or affect ENU initiated brain tumorigenesis.
Collapse
Affiliation(s)
- Tomoyuki Shirai
- Department of Experimental Pathology and Tumor Biology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|