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

[種々の1.8GHzの携帯電話信号にばく露されたヒト栄養膜細胞におけるHSP70発現。] med./bio.

HSP70 expression in human trophoblast cells exposed to different 1.8 Ghz mobile phone signals

著者: Franzellitti S, Valbonesi P, Contin A, Biondi C, Fabbri E
掲載誌: Radiat Res 2008; 170 (4): 488-497
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この研究は、1.8 GHzの連続波（CW）および２種類のGSM信号（GSM-217Hz and GSM-Talk）の長期ばく露（4〜24時間）をヒト栄養膜由来細胞株HTR-8 / SVneoに与え、細胞応答に対する時間および変調方式の考えられる影響を評価するために熱ショックタンパク質HSP70の遺伝子とタンパク質発現を測定した。その結果、誘導的発現性のHSP70タンパク質の発現は、実験された任意の条件下において高周波EMFにより変化しなかった；同じく、誘導的発現性のHSP70A、HSP70B、および恒常的発現性のHSC70の転写産物も、連続波、変調波、かつ変調方式にかかわらず、EMFにより変化しなかった；その代わりに、誘導的発現性のHSP70C転写産物のレベルは、GSM-217Hz信号への24時間のばく露後に有意に増加し、GSM-Talk信号への4時間および16時間のばく露後に有意に減少した、と報告している。

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研究目的（著者による）

To study HSP70 gene expression and protein expression in human trophoblast cells after exposure to 1.8 GHz (continuous wave and different GSM signals) to assess the possible effects of time and modulation schemes on cell responses.

詳細情報

Experiments for each modulation scheme were carried out with three different exposure periods (4, 16 and 24 hours). For each condition, six independent experiments were performed for gene expression and protein expression. Positive controls were performed with 43 °C heat (1 h) and negative controls were performed in the incubator.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1.8 GHz
Modulation type: CW
ばく露時間: intermittent, 5 min on/10 min off, for 4, 16, and 24 h
  • SAR: 2 W/kg average over time
ばく露2: 1.8 GHz
Modulation type: pulsed
ばく露時間: intermittent, 5 min on/10 min off, for 4, 16, and 24 h
  • SAR: 2 W/kg average over time
  • SAR: 16 W/kg peak
ばく露3: 1.8 GHz
Modulation type: pulsed
ばく露時間: intermittent, 5 min on/10 min off, for 4, 16, and 24 h
  • SAR: 2 W/kg average over time
  • SAR: 22.77 W/kg peak

ばく露1

主たる特性
周波数 1.8 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 intermittent, 5 min on/10 min off, for 4, 16, and 24 h
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
チャンバの詳細 The exposure system was developed and built following the specifications in [Schonborn et al., 2000]. Two 128.5 x 65 x 424 mm³ brass single-mode waveguide resonators equipped with ventilators and air temperature probes were placed inside one of the two incubators.
ばく露装置の詳細 Six 35-mm Petri dishes per resonator, each containing 3 ml of medium, were arranged in two stacks using a plastic holder and were placed in the H-field maximum of the standing wave (E-polarization).
Sham exposure A sham exposure was conducted.
Additional information Within each experiment, six dishes each were RF and sham exposed. Signal characteristics and the exposure/sham condition were assigned to the two waveguides by a computer-controlled signal unit ensuring blinded conditions.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 2 W/kg average over time 測定値および計算値 - -
Additional parameter details

The absolute uncertainty on SAR was 20%, and the variation due to the non-uniformity of the field distribution was 29%. The temperature of the monolayer cells was uniformly distributed without localized hot spots. The increase in temperature due to the RF field was well below 0.1°C per unit SAR with a thermal time constant of 280 s. The temperature differences between RF and sham exposed cells were below 0.1°C.

測定および計算の詳細

The system was characterized numerically by FDTD simulation, and results were verified extensively using a near-field scanner DASY3 equipped with dosimetric field and temperature probes [Schuderer et al., 2004]. Direct temperature measurements were performed in preliminary experiments using a temperature probe inserted in the medium which confirmed the results of the simulation.

ばく露2

主たる特性
周波数 1.8 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 intermittent, 5 min on/10 min off, for 4, 16, and 24 h
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Additional information

GSM-217 Hz signal (speaking only) with every 26th frame being idle, adding an 8 Hz modulation component [Pedersen, 1997]
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
SAR 2 W/kg average over time 測定値および計算値 - -
SAR 16 W/kg peak 測定値および計算値 - -

ばく露3

主たる特性
周波数 1.8 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 intermittent, 5 min on/10 min off, for 4, 16, and 24 h
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Pulse type rectangular
Additional information

GSM-Talk signal (33% speaking and 67% hearing) with temporal changes between GSM-217 Hz and GSM-DTX (transmission reduced to 12 active frames per 104 frames) resulting in 2, 8, and 217 Hz modulation components
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
SAR 2 W/kg average over time 測定値および計算値 - -
SAR 22.77 W/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:
  • ばく露後

研究の主なアウトカム（著者による）

There were no significant differences in cell viability between all groups. No significant differences in either HSC70 or HSP70 protein expression were observed between radiofrequency electromagnetic field exposed and sham exposed samples. After exposure to heat shock the trophoblast cells showed a significant overexpression of the HSP70 protein, while HSC70 was unaffected. The HSP70-A, HSP70-B and HSC70 transcripts did not change in cells exposed to radiofrequency electromagnetic fields. Levels of the HSP70-C transcript were significantly enhanced after 24 hours exposure to GSM-217 Hz and reduced after 4 hours and 16 hours exposure to GSM-talk signals.
The results suggest that the expression analysis for multiple transcripts, though encoding the same or similar protein products, can identify subtle changes that would not be detected at the protein level.

研究の種別:

研究助成

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