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

[適度の温度上昇はL929細胞のODC活性に影響する:低レベルのラジオ周波数では影響は見られない] med./bio.

Modest increase in temperature affects ODC activity in L929 cells: Low-level radiofrequency radiation does not.

掲載誌: Radiat Environ Biophys 2006; 45 (3): 231-235

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研究目的(著者による)

To study the effects of low-level radiofrequency irradiation and elevated temperature (< 1°C) on ornithine decarboxylase activity in murine fibroblasts.

詳細情報

Changing of culture medium and 50 Hz sine wave magnetic field (10 µT) were used as positive controls.

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 2, 8 or 24 h
  • SAR: 0.2 W/kg (0.1-0.3 W/kg)
  • SAR: 0.4 W/kg (0.3-0.5 W/kg)
ばく露2: 900 MHz
Modulation type: CW
ばく露時間: continuous for 2, 8 or 24 h
  • SAR: 0.2 W/kg (0.1-0.3 W/kg)
  • SAR: 0.4 W/kg (0.3-0.5 W/kg)

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 2, 8 or 24 h
Modulation
Modulation type pulsed
Repetition frequency 217 Hz
Additional information

GSM modulation

ばく露装置
ばく露の発生源/構造
  • モノポール
  • 導波管
  • see setup and chamber details
チャンバの詳細 The waveguide exposure chamber was an aluminium RF resonator with a plastic cultivation chamber and a water circulation heat exchanger for keeping the temperature of the cell culture medium constant (± 0.3°C). The water circulated under a glass surface on which the cell-culture dishes were placed. Glass Petri dishes were used instead of plastic dishes for better thermal contact. There were two identical chambers, one for exposure and one for sham-exposure. However, the temperature of the water circulation heat exchanger in the exposure chamber (37.5 ± 0.3°C) was found to be, on average, 0.8°C higher than in the sham exposure chamber (36.7 ± 0.3°C), despite the temperature control. Warm air (approx. 37°C) and CO2 (5%) were fed into the cultivation chambers from a cell culture incubator.
ばく露装置の詳細 The RF power source consisted of a signal generator, a 217 Hz GSM modulator, and power amplifier. RF power was fed into the exposure chamber with a monopole post, and the electric field inside the chamber, below the heat exchanger, was monitored from another monopole post with an RF power meter.
Additional information Two Petri dishes were exposed simultaneously, and two dishes were sham-exposed. This was repeated 3-5 times at each exposure level and duration. In separate additional experiments, cells were incubated in ordinary cell culture incubators for 2 h at 37.6°C and 36.5°C measured with a Fluke thermometer and thermocouple in the medium. Magnetic fields were measured in both incubators to be 1.1 µT at 50 Hz at the position of the cell dishes. Cells were handled exactly in the same way as in the exposures in the waveguide system.
パラメータ
測定量 種別 Method Mass 備考
SAR 0.2 W/kg - 測定値および計算値 - 0.1-0.3 W/kg
SAR 0.4 W/kg - 測定値および計算値 - 0.3-0.5 W/kg

ばく露2

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 2, 8 or 24 h
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 種別 Method Mass 備考
SAR 0.2 W/kg - 測定値および計算値 - 0.1-0.3 W/kg
SAR 0.4 W/kg - 測定値および計算値 - 0.3-0.5 W/kg

Reference articles

  • Penafiel LM et al. (1997): [L929細胞でのオルニチン脱炭酸酵素活性に対するマイクロ波の影響における変調の果たす役割]

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)

Radiofrequency irradiation did not affect cellular ornithine decarboxylase activity. However, a slight increase in temperature (0.8-0.9°C) in the exposure system resulted in decreased ornithine decarboxylase activity in cell cultures. This was verified by tests in which cells were exposed to different temperatures in incubators (37.6°C and 36.5°C).
The data showed that ornithine decarboxylase activity is sensitive to small temperature differences in cell cultures.

研究の種別:

研究助成

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