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

[835.62、847.74 MHz携帯電話周波数照射によるC3H 10T1/2胚線維芽細胞での腫瘍形成遺伝子mRNAレベルと転写因子活性] med./bio.

Proto-oncogene mRNA levels and activities of multiple transcription factors in C3H 10T 1/2 murine embryonic fibroblasts exposed to 835.62 and 847.74 MHz cellular phone communication frequency radiation

著者: Goswami PC, Albee LD, Parsian AJ, Baty JD, Moros EG, Pickard WF, Roti Roti JL, Hunt CR
掲載誌: Radiat Res 1999; 151 (3): 300-309
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＜目的＞携帯電話から発生する変調されたラジオ波が、様々なストレス応答を引き起こすかどうかを調べる。 ＜方法＞増殖期、定常期の初期、定常期のマウスの細胞に4日間ラジオ波を照射した。それらの細胞からRNA抽出し、RT-PCRを行い、fos、jun、mycのmRNAの発現レベルを調べた。また、タンパクを抽出し、Gel MobilityShift Assayを行ってAP-1、AP-2、NF-kapperBのDNA結合活性を調べた。さらに血清刺激の影響も調べた。 ＜結果＞jun、mycのmRNAの発現レベルは、曝露開始時の細胞増殖の段階に関係無く変化しなかった。また、DNA結合活性はいずれも変化しなかった。しかし、fosだけはほとんどの条件で増加した。

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研究目的（著者による）

To determine whether two different modulated radiofrequencies of the type generally used in cellular phones (835.62 MHz (FMCW) and 835.62 MHz (CDMA)) could elicit a general stress response in a biological system.

詳細情報

Changes in proto-oncogene expression, determined by measuring Fos, Jun, and Myc mRNA levels as well as by the DNA-binding activity of the AP1, AP2 and NFkB transcription factors, were used as indicators of a general stress response.

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 24 h or 4 days
FMCW
  • SAR: 0.6 W/kg mean (± 0.3 W/kg)
ばく露2: 847.74 MHz
ばく露時間: continuous for 24 h or 4 days
CDMA
  • SAR: 0.6 W/kg mean (± 0.3 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 24 h or 4 days
Additional information FMCW
Modulation
Modulation type cf. additional information
Additional information

FMCW
ばく露装置
ばく露の発生源／構造
チャンバの詳細 A detailed description of the radial transmission line (RTL) and a temperature-controlled facility containing nine RTLs has been given in the reference articles. The RTL is a shielded irradiator consisting of a parallel-plate region (43 mm spacing, total radius of 533 mm) with the bottom aluminium plate acting as a thermal homogenizer for the flasks. A central conical antenna (203 mm in diameter) emitted TEM waves radially outward that were terminated by RF-absorbing material backed by a lamina of perforated aluminium.
ばく露装置の詳細 A total of 16 T-75 culture flasks each containing 40 ml of medium could be distributed angularly around the antenna. The cell layer in the flasks was subjected to a perpendicular EF and a circumferential MF perpendicular to the EF and the direction of propagation inducing a radial component to the EF.
Sham exposure A sham exposure was conducted.
Additional information Sham exposures were performed in an identical RTL without the RF field. The temperature of the culture medium was maintained at 37.0 ± 0.25°C by feedback controllers for each RTL.
パラメータ
測定量 値 種別 Method Mass 備考
SAR 0.6 W/kg mean 推定値 - ± 0.3 W/kg
測定および計算の詳細

An extensive analytical, numerical and experimental evaluation was carried out using both thermometric and thermographic techniques to map power deposition distributions (see reference article on dosimetry). The larger than usual amount of culture medium (40 instead of 15 ml) was needed to reduce SAR non-uniformities. Results from a fast temperature differential thermometry measurement on a fully loaded RTL at 835.62 MHz were used for estimating the SAR for the input power applied to the RTL during the experiments. The high-SAR region at the centre of the flask was 1.5 dB higher and the low-SAR regions were approx. 3 dB lower than the average SAR for a typical flask.

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 24 h or 4 days
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 推定値 - ± 0.3 W/kg

Reference articles

  • 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]
  • Moros EG et al. (1999): [40匹の小型哺乳類に対する長期UHF同時照射に用いる小型遮蔽ばく露装置。第2部。ドシメトリ]

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）

Exposure of cells to a FMCW or CDMA field did not result in any significant variation in Jun and Myc mRNA levels or the DNA-binding activities of AP1, AP2, and NFkB.
Thus it is concluded that it is unlikely that the radiofrequency field is capable of eliciting a general stress response in cells of this cell line. However, the statistically significant increase in Fos expression suggests that the radiation could affect expression of specific genes.

研究の種別:

研究助成

Replication studies

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