研究のタイプ: 医学／生物学の研究 (experimental study)

[ヒトTリンパ球（Jurkat）の無線周波電磁界に対する反応] med./bio.

[The reaction of human T-lymphocytes (Jurkat) to high-frequency electromagnetic fields]

著者: Meyer R, Gollnick F, Wolke S, Conrad G, Bock H
掲載誌: Edition Wissenschaft 1996; 10: 3-22
Journal not peer-reviewed
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この論文は、社団法人die Forschungsgemeinschaft Funk （1992年から活動している研究資金提供団体）へのドイツ語の研究報告書である。研究課題は、リンパ球の免疫刺激のシグナル伝達カスケードと電磁界との相互作用を調べることであった。Tリンパ球の免疫刺激は、細胞膜の外表面にあるT細胞受容体複合体への抗原分子の結合から始まる。この結合がシグナル伝達カスケードを誘発し、最終的にインターロイキン分子の分泌と細胞分裂を引き起こす。この連鎖の初期段階で、細胞内カルシウム濃度[Ca2 +] iの上昇が注目される。そこで、Jurkat細胞の[Ca2 +] iに対するパルス高周波電磁界の影響に焦点を当てた。パルス高周波電磁界の搬送周波数およびパルス化パターンは、モバイル通信のGSM標準をシミュレートし、非熱的レベルでのばく露にはTEMセルを用いた。TEMセル内は、細胞懸濁液で満たされ、200 μlの容量を持ち、TEMセル内の電界を乱すことなく、細胞を顕微鏡で観察できるように設計されている。SARの時間的および空間的平均は、900 MHzで15.4 mW / kg、1800 MHzで13.5 mW / kgであった。培養ヒトT細胞の[Ca2 +] iは、蛍光指示薬色素fura-2によって測定され、デジタル画像分析を適用して定量化された。その結果、すべての実験で合計1272個の細胞が調査されたが、TEM細胞の内側と外側の細胞の挙動に違いはなかった、と報告している。

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研究目的（著者による）

To investigate the effects of pulsed high-frequency fields on the [Ca2+]i in a T-cell line, Jurkat cells.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 900 MHz
Modulation type: pulsed
ばく露時間: continuous for 500 s
  • 電力: 5 W peak
  • SAR: 15.4 mW/kg mean (averaged over time and space)
  • SAR: 123.2 mW/kg peak
ばく露2: 1,800 MHz
Modulation type: pulsed
ばく露時間: continuous for 500 s
  • 電力: 2.8 W peak
  • SAR: 13.5 mW/kg mean (averaged over time and space)
  • SAR: 96.3 mW/kg peak

ばく露1

主たる特性
周波数 900 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 500 s
Modulation
Modulation type pulsed
Duty cycle 14 %
Repetition frequency 217 Hz
Pulse type rectangular
ばく露装置
ばく露の発生源／構造
  • TEMセル
  • 7 cm x 7 cm x 7 cm, signal generator
チャンバの詳細 The TEM cell was designed to fit on top of the inverted microscope and consisted of two separate parts, i.e. the upper part with the septum (the TEM cell itself), and the rectangular bottom plate containing the 1-cm test chamber for holding the biological material. The bottom of this chamber consisted of a glass coverslip and a 1-mm metal mesh made of 0.05-mm wire and provided shielding while allowing optical observation. A detailed description can be found in the partial report on "Expositionseinrichtungen" [Neibig, 1996].
ばく露装置の詳細 The sample volume (200 µl perfusion fluid with cells) in a Plexiglas container was maintained at a constant temperature by an exchange of the fluid preheated to 37 °C and an additional heating fluid running through a circular channel around the sample volume.
Sham exposure A sham exposure was conducted.
Additional information An experimental run consisted of three phases each lasting 500 s. The first phase without any exposure was followed by field or sham exposure. During the third phase a chemical stimulation was performed in order to provoke a response of the cells which served as positive control.
パラメータ
測定量 値 種別 Method Mass 備考
電力 5 W peak 測定値 - -
SAR 15.4 mW/kg mean 測定値および計算値 - averaged over time and space
SAR 123.2 mW/kg peak 測定値および計算値 - -
測定および計算の詳細

The SAR value achieved was determined by combined measurements and calculations. Additional information can be found in the partial report on "Expositionseinrichtungen" [Neibig, 1996]. Field distribution and SAR for 1 W CW were calculated using the "MAFIA" program. The power transmitted into the TEM cell was measured separately for all applied signals using a bolometer. Additionally, control measurements were performed with a spectrum analyzer and a millivoltmeter. Finally, the actual SAR values were calculated for both carrier frequencies with their pulse patterns. The SAR values calculated on this basis were only spatial mean values. The metal mesh, however, created local field inhomogeneities at the level of the cells since the field lines converged towards the wires of the mesh. Calculations on this showed that the field strength varied by a factor of 3 and SAR values thus by a factor of 9.

ばく露2

主たる特性
周波数 1,800 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 500 s
Modulation
Modulation type pulsed
Duty cycle 14 %
Repetition frequency 217 Hz
Pulse type rectangular
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
Sham exposure A sham exposure was conducted.
パラメータ
測定量 値 種別 Method Mass 備考
電力 2.8 W peak 測定値 - -
SAR 13.5 mW/kg mean 測定値および計算値 - averaged over time and space
SAR 96.3 mW/kg peak 測定値および計算値 - -

Reference articles

ばく露を受けた生物:

方法 影響評価項目／測定パラメータ／方法

研究対象とした生物試料:
調査の時期:
  • ばく露中

研究の主なアウトカム（著者による）

The number of cells with calcium oscillations during exposure to the 900 MHz field was not different from that during sham exposure. In the case of 1800 MHz fields 17.7% of cells started calcium oscillations during exposure, whereas only 10.9% of cells started calcium oszillations during sham exposure. This might indicate an increase in calcium oscillations due to the field exposure. Evaluation of the averaged [Ca2+]i showed small increase in [Ca2+]i soon after the field had been switched on. This increase was present in both exposed groups, 900 and 1800 MHz, but it was visible in any of the sham exposed groups.

研究の種別:

研究助成

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