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

[熱ショック因子は携帯電話周波数のマイクロ波にばく露された哺乳類細胞において活性化されない] med./bio.

The heat-shock factor is not activated in mammalian cells exposed to cellular phone frequency microwaves

著者: Laszlo A, Moros EG, Davidson T, Bradbury M, Straube W, Roti Roti J
掲載誌: Radiat Res 2005; 164 (2): 163-172
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この研究は、FDMAまたはCDMA変調マイクロ波の低レベルばく露（SAR = 0.6 W / kg））および高レベルばく露（SAR = 約5 W / kg）を受けたハムスター、マウス、およびヒトの細胞における熱ショック因子（HSF）のDNA結合活性の活性化を調べた。ストレス応答誘導の最初のステップは、この応答に関与する特定の転写因子であるHSFのDNA結合活性の活性化であるので、この活性を、ゲルシフトアッセイ用いて評価した。このアッセイのキャリブレーションにより、温度が1度上昇した後、HSFのDNA結合活性の活性化が約10％増加することが検出された。その結果、アッセイの感度の範囲内で、テストされたばく露の結果として、培養哺乳類細胞におけるHSFのDNA結合能力の増加は検出できなかった；この知見は、携帯電話関連のマイクロ波へのばく露の結果としてストレス応答が活性化されるという仮説は支持されなかった、と報告している。

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研究目的（著者による）

To determine whether acute and chronic exposures to FDMA- or CDMA -modulated microwaves have effects on the stress response of human and rodent cells. The activation of the DNA-binding activity of heat-shock factor (HSF) which leads to the transcription of heat shock proteins was measured.

詳細情報

The experiments were conducted in an exposure system with reliable and precise temperature control. The gel shift assay was calibrated to detect an increase of about 10 % in the activation of the DNA-binding activity of heat-shock factor after an increase of 1° C in temperature.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 835.62 MHz
ばく露時間: continuous for 5, 15, 30 and 60 min or 24 h
FDMA
  • SAR: 0.6 W/kg mean (± 0.3 W/kg)
  • SAR: 5 W/kg mean (4.4-5 W/kg)
ばく露2: 847.74 MHz
ばく露時間: continuous for 5, 15, 30 and 60 min or 24 h
CDMA
  • SAR: 0.6 W/kg mean (± 0.3 W/kg)
  • SAR: 5 W/kg mean (4.4-5 W/kg)

ばく露1

主たる特性
周波数 835.62 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 5, 15, 30 and 60 min or 24 h
Additional information FDMA
Modulation
Modulation type cf. additional information
Additional information

FDMA
ばく露装置
ばく露の発生源／構造
チャンバの詳細 The irradiator facility was set up in a temperature-controlled room. It consisted of 10 radial transmission line (RTL) irradiators formed by two parallel metal plates 4.3 cm apart with the bottom aluminium plate providing mechanical support and temperature equalization among flasks. Each RTL irradiator had a central conical antenna that emitted TEM waves radially outward through the cavity that was bounded by an annulus of RF-absorbing foam backed by a perforated aluminium lamina. The design and calibration of these irradiators used in several studies have been described in detail in the reference articles.
ばく露装置の詳細 Up to 16 T-75 sealed culture flasks each containing 40 ml of medium (to minimize edge effects) were positioned in each of the RTLs around the antenna. The high SAR values were obtained by loading each flask dielectrically with a shim of alumina (Al2O3) ceramic as described previously.
Additional information The temperature of the culture medium in the flasks was maintained at 37 ± 0.3°C with the aid of thermocouples on the bottom plate of the RTL that were calibrated periodically using intraflask fibre-optic probes. All exposures were performed after the warm-up cycle of the RTL was complete.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 0.6 W/kg mean 測定値および計算値 - ± 0.3 W/kg
SAR 5 W/kg mean 測定値および計算値 - 4.4-5 W/kg
測定および計算の詳細

Thermometric and thermographic techniques were used for mapping the SAR. The SARs for both FDMA and CDMA were based on measured values at 835.62 MHz CW and were scaled to input power. The calculated spatial SAR distribution in a T-75 flask showed some heterogeneity but results from model calculations indicated that this non-uniformity should not result in hiding of a small effect.

ばく露2

主たる特性
周波数 847.74 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 5, 15, 30 and 60 min or 24 h
Additional information CDMA
Modulation
Modulation type cf. additional information
Additional information

CDMA
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
パラメータ
測定量 値 種別 Method Mass 備考
SAR 0.6 W/kg mean 測定値および計算値 - ± 0.3 W/kg
SAR 5 W/kg mean 測定値および計算値 - 4.4-5 W/kg

Reference articles

  • Pickard WF et al. (2000): [誘電体装荷放射状送電線における培養瓶内のSAR分布の実験的および数的測定]
  • Moros EG et al. (1999): [大量の培養瓶へのマイクロ波照射用広帯域遮蔽ばく露装置としての放射状送電線]

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）

The acute and chronic exposure of human and rodents cells in culture to FDMA- and CDMA-modulated microwaves did not result in the activation of the DNA-binding activity of heat-shock factor which is a necessary condition for induction of stress response and the synthesis of heat shock proteins.

研究の種別:

研究助成

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