この論文は、超低周波電磁界（ELF-EMF）へのばく露が遺伝子発現に影響するか否かを調べるために、ボランティアにELF-EMFばく露を行い、その間に採血した白血球での遺伝子発現の変化をDNAマイクロアッセイ法で調べた。17組の男性ボランティア（20-30歳）は、1辺1mの正方形コイル（50巻きコイル2つから成る）が1mの間隔で対向する立方体のばく露フレーム中央に座り、EMDEX IIを首からぶら下げた。ばく露時間は2時間とし、50Hz磁界強度は、ばく露時62.0±7.1 μT（2つの50巻きコイルに同方向の電流を流す）、擬似ばく露時0.21±0.05 μT（2つの50巻きコイルに逆方向の電流を流す）、無ばく露時0.085±0.05 μT（電流を流さない）であった。第1組は、実験1日目にばく露、その翌日に擬似ばく露、その6日後にばく露、その翌日に無ばく露の順で実験し、第2組は、ばく露と擬似ばく露（無ばく露）を逆順で行った。各実験では、2時間の実験中の5回を含め、全部で10回採血（各10ml）を行った。各組毎に、17人分のRNAサンプルをばく露条件と採血時間を合わせてプールし、分析した。前初期遺伝子やストレス反応・細胞増殖・アポトーシスの関連遺伝子を含め、これまでにELF-EMFの影響が報告されている16の哺乳類遺伝子の経時変化を調べた結果、ELF-EMFばく露に反応したプロファイルを一貫して示した遺伝子および遺伝子セットはなかったと報告している。
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To determine if gene expression changes occur in white blood cells of volunteers exposed to an extremely low frequency magnetic field, each of 17 male volunteer pairs was subjected either to a 50 Hz magnetic field for 2 h or to a sham exposure at the same time (11-13 h).
The alternative regime for each volunteer was repeated on the following day and the two-day sequence was repeated 6 days later, with the exception that a null exposure replaced the sham exposure.
Five blood samples were collected at 2 h intervals (from 9-17 h) with five additional samples during the exposure and sham exposure or null exposure (at 5, 10, 20, 40 and 80 min). RNA samples were pooled for the same time on each study day for the group of 17 volunteers.
ばく露時間: continuous for 120 min
Each the 17 volunteer pairs underwent a sequence of exposure followed by a sham exposure on consecutive days in the first week, which was repeated the following week with the exception that the sham exposure was replaced by a null exposure. The other volunteer in each pair simultaneously underwent the reverse exposure sequences.
|ばく露時間||continuous for 120 min|
|ばく露装置の詳細||two exposure frames (1 m³) consisted of an acrylic former upon which the field-generating coils were wound on each of the vertical sides; coils were wound with 100 turns with two interleaved sets of 50 turns, which permitted current flow to be in the same or opposite directions; if the current is unidirectional through the two sets of windings, a field is generated; when the currents passing through the two coils are in opposing directions, a sham exposure is produced in which the field strength is cancelled, but other conditions, such as total current remain the same; the two frames were 5.4 m apart in the study room; volunteer sat within exposure frame|
|Sham exposure||A sham exposure was conducted.|
|磁束密度||62 µT||-||測定値||-||± 7.1 µT (at the center of the frame)|
No genes or gene sets showed consistent response profiles to extremely low frequency magnetic field exposures. A stress response was detected as a transient increase in plasma cortisol at the onset of either exposure or sham exposure on the first study day. The cortisol response diminished progressively on subsequent exposures or sham exposures, and was attributable to mild stress associated with the experimental protocol.