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

[GMSK相変調マイクロ波ばく露後のヒトリンパ球での遺伝毒性ダメージ] med./bio.

Cytogenetic damage in human lymphocytes following GMSK phase modulated microwave exposure

著者: d'Ambrosio G, Massa R, Scarfi MR, Zeni O
掲載誌: Bioelectromagnetics 2002; 23 (1): 7-13
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この研究は、ヒトリンパ球を用いたインビトロ実験で、無変調または位相変調マイクロ波へのばく露が、細胞増殖動態の変化および／または遺伝毒性影響を引き起こすか否かを、細胞質分裂阻害増殖指数および小核頻度で評価した。ヒト末梢血培養物に、1.748 GHzの連続波（CW）または位相変調波（GMSK）のいずれかのばく露を15分間与えた。SARの最大値は約5 W / kgとなった。このレベルは、携帯電話ユーザの頭部内レベルより高くなる。その結果、CWまたはGMSK電磁界へのばく露のどちらにおいても、細胞増殖動態の変化は見られなかった；小核頻度に、CWばく露の影響は見られなかったが、GMSKへのばく露では、有意な小核頻度の変化が見られた、と報告している。

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研究目的（著者による）

To study whether exposure to a microwave frequency used for mobile communication (unmodulated or in presence of phase only modulation) can cause modification of cell proliferation kinetics and/or genotoxic effects.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1.748 GHz
ばく露時間: continuous for 15 min
  • SAR: 2.25 W/kg mean (± 0.87 W/kg)
  • SAR: 4.99 W/kg (± 0.24 W/kg)
ばく露2: 1.748 GHz
Modulation type: CW
ばく露時間: continuous for 15 min
  • SAR: 2.25 W/kg mean (± 0.87 W/kg)
  • SAR: 5.02 W/kg (± 0.22 W/kg)

ばく露1

主たる特性
周波数 1.748 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 15 min
Additional information GMSK
Modulation
Modulation type cf. additional information
Additional information

Only the GMSK (Gaussian minimum shift keying) phase modulation was applied to the signal at a modulating bit rate of 1/T = 270.833 kbit/s, and the 3 dB bandwidth was such that BT = 0.3. Voice modulation was simulated by a 9 bit pseudorandom sequence.
ばく露装置
ばく露の発生源／構造
チャンバの詳細 The amplified microwave signal was fed through a coaxial isolator and a coaxial double bridge into the sample holder, a rectangular cavity (110 x 55 x 184 mm) made of two coax to rectangular waveguide adapters.
ばく露装置の詳細 The narrow side of the waveguide and the E field were horizontal, parallel to the culture liquid layer (10 ml contained in a 25 cm² rectangular Falcon plastic flask). Due to small differences in the volume and positioning of the samples, the incident power was adjusted at the beginning of each exposure to obtain nearly the same power loss in all 18 experiments (nine CW and nine GMSK).
Additional information A thermostated (35 ± 0.1 °C) water jacket surrounded the sample holder cavity. The sample temperature, on its own, was allowed to rise from 35 ± 0.1 °C to no more than 35.7 ± 0.1 °C at the end of the exposure. No sham exposure was performed. Unexposed control cultures were left in the incubator at 37 ± 0.2 °C.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 2.25 W/kg mean 測定値および計算値 - ± 0.87 W/kg
SAR 4.99 W/kg - 電力損失による決定値 10 g ± 0.24 W/kg
測定および計算の詳細

The incident, reflected, and transmitted RF powers were measured during the actual exposure using power sensors and power meters, and the power lost in the sample holder unit (sample included) was evaluated. From this, the power lost per unit mass of the sample (m = 10.4 g) was 5.02 ± 0.22 W/kg for the CW exposures and 4.99 ± 0.24 W/kg for the GMSK exposures. These evaluations were checked by means of calorimetric measurements, performed following the technique suggested by Allis et al. [1977]. Heating and cooling curves were recorded at nine different points of a dummy sample (culture medium alone) using point like thermocouples and temperature monitors. From the nine temperature curves, nine local SARs were calculated: the mean value was 2.25 W/kg, with an SD of 0.87 W/kg (minimum value 1.17 W/kg and maximum value 3.93 W/kg). These SAR values were considerably less than the total power lost per unit mass of the sample (see above), that included the losses of the sample holder structure. Due to the large uncertainties of SAR evaluations based on temperature measurements [Burkhardt et al., 1996], the mean value of power lost (~5 W/kg) can be assumed as an upper bound, actually never exceeded by the power absorbed by the sample.

ばく露2

主たる特性
周波数 1.748 GHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 15 min
Modulation
Modulation type CW
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 2.25 W/kg mean 測定値および計算値 - ± 0.87 W/kg
SAR 5.02 W/kg - 電力損失による決定値 10 g ± 0.22 W/kg

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）

A first set of experiments was performed by exposing the cultures to unmodulated (continuous wave) radiation and no significant difference was found (either in micronuclei or in cell proliferation kinetics). Other experiments were carried out by exposing the samples to phase modulated radiation, and a significant difference in micronuclei was found. This result would indicate a genotoxic effect of phase modulation.

研究の種別:

研究助成

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