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

[携帯電話用1.439 GHz電磁界への慢性ばく露はF344ラットのENU誘発中枢神経系腫瘍をプロモートしない] med./bio.

Chronic exposure to a 1.439 GHz electromagnetic field used for cellular phones does not promote N-ethylnitrosourea induced central nervous system tumors in F344 rats.

掲載誌: Bioelectromagnetics 2005; 26 (1): 59-68

この研究は、携帯電話が発生する電磁界と同等の電磁界EMF)への2年間のばく露ラット中枢神経系(CNS)の腫瘍発生を加速するか否かを調べた。妊娠18日目に、N-エチルニトロソウレア(ENU)の子宮ばく露により脳腫瘍形成をイニシェートした。その後出生した合計500匹の仔ラットを5群に分けた(各群はオス50匹、メス50匹で構成された)。第1群は無処置対照群、第2群はENU単独処置群、第3-4群はENU + EMF擬似ばく露および2つのばく露レベル)である。パーソナルデジタルセルラー(PDC)の1.439 GHz時分割多元接続(TDMA)信号の頭部へのばく露を5週齢から開始した。ばく露時間は1日90分、1週5日で104週間継続した。脳の平均比吸収率SAR)は、低および高ばく露でそれぞれ0.67および2.0 W / kgであり、一方、全身平均SARは0.4 W / kg未満であった。結果として、5つの群の間に、体重、摂食量、生存率に差はなかった;EMFばく露群において、雌雄どちらでも、脳腫瘍および/または脊髄腫瘍発生率または発生数に増加はなかった;さらに、腫瘍タイプの明確な変化は明らかでなかった、と報告している。

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研究目的(著者による)

To evaluate whether a 2 year exposure to an electromagnetic field equivalent to that generated by cellular phones can accelerate tumor development in the central nervous system of rats (brain tumorigenesis was initiated by an intrauterine exposure to N-ethylnitrosourea on gestational day 18).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1.439 GHz
Modulation type: pulsed
ばく露時間: repeated daily exposure, 90 min/day, 5 days/week for 104 weeks
  • SAR: 2 W/kg average over mass (brain)
  • SAR: 6 W/kg peak (brain) (time peak)
  • SAR: 0.67 W/kg average over mass (brain)
  • SAR: 2 W/kg peak (brain) (time peak)
  • SAR: 0.4 W/kg average over mass (whole body)

General information

A total of 500 pups were divided into five groups: untreated control, ENU alone, ENU + EMF (two exposure levels + sham). N.B.: ENU treatment was done to their mothers on gestational day 18!

ばく露1

主たる特性
周波数 1.439 GHz
タイプ
  • electromagnetic field
ばく露時間 repeated daily exposure, 90 min/day, 5 days/week for 104 weeks
Modulation
Modulation type pulsed
Additional information

TDMA signal for the Japanese PDC (Personal Digital Cellular) system

ばく露装置
ばく露の発生源/構造
  • モノポール
Distance between exposed object and exposure source 30 mm
チャンバの詳細 The exposure box was 90 x 90 x 60 cm, the inside walls except for the ceiling being covered with electromagnetic absorber. Ten boxes were used simultaneously.
ばく露装置の詳細 Ten rats, fixed individually in plastic tubes (four different sizes), were set on a disk-shaped plate (65 cm in diameter) with their nose towards the center. A quarter-wavelength monopole antenna on the ceiling of the exposure box fitted in the center of the disk-shaped plate. The distance between the antenna and each rat nose was 30 mm and the distance between the ceiling and the rat back was 5 mm.
Additional information Plastic holders used were of four different sizes (inner diameter 4.0 cm, 4.7 cm, 5.5 cm, and 6.2 cm). If rats deceased, dummy rats were used to maintain symmetry and scheduled SAR in the exposure box.
パラメータ
測定量 種別 Method Mass 備考
SAR 2 W/kg average over mass 測定値および計算値 brain -
SAR 6 W/kg peak 測定値および計算値 brain time peak
SAR 0.67 W/kg average over mass 測定値および計算値 brain -
SAR 2 W/kg peak 測定値および計算値 brain time peak
SAR 0.4 W/kg average over mass 推定値 whole body -

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:
研究対象とした臓器系:
  • CNS, heart, liver, kidney, spleen, pituitary gland, adrenal glands, testes, ovary
調査の時期:
  • ばく露中
  • ばく露後

研究の主なアウトカム(著者による)

There were no differences between the groups in body weights, food consumption, and survival rates. No increase in the incidences per group of brain and/or spinal cord tumors, either in the males or females, was revealed in the exposed rats. Additionally, no clear changes in tumor types were evident.
In conclusion, under the present experimental conditions, 1.439 GHz electromagnetic field exposure to the heads of rats for a 2 year period was not demonstrated to accelerate or affect N-ethylnitrosourea initiated brain tumorigenesis

研究の種別:

研究助成

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