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

[1.25 GHzの連続ラジオ周波数電磁界にばく露されたニワトリの胚の温度変化] med./bio.

Temperature changes in chicken embryos exposed to a continuous-wave 1.25 GHz radiofrequency electromagnetic field

著者: Thalau HP, Raczek J, Marx B, Hombach V, Cooper J
掲載誌: Radiat Res 2003; 159 (5): 685-692
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この研究は、ニワトリ（ホワイトレグホン）の有精卵（n = 550）に高周波電磁界ばく露を与えた時の組織の温度変化に的を絞った研究である。ここでは、直接的には生体影響の検討は行っていないが、得られる知見は、奇形または胚致死への非熱的な影響の研究にとって重要であると著者は述べている。ばく露条件は、周波数1.25 GHzの連続波、電力密度は9.0〜0.75 mW / cm2の範囲の6つの異なるレベル、ばく露期間は、長期ばく露（21日間の全孵卵期間）と短期ばく露（1〜2時間/日）とした。胚組織と羊水それぞれの温度は、挿入された温度プローブで測定された。結果として、胚発生の21日間を通じて、ばく露中の卵の平均温度上昇は、電力密度1.25 mW / cm2のばく露では最大0.25 ℃、9.0 mW / cm2では最大2.3 ℃であった；それぞれの全身SAR最大値は1.45および10.44 W / kgであった；0.75 mW / cm2（全身SAR= 0.87 W / kg）では、温度上昇は温度プローブの測定精度（±0.1 ℃）の範囲内であった；電磁界ばく露による温度上昇は、孵卵の最初の１週間で最大であり、第3週（孵化前の最後の週）には、温度上昇が小さくなった；短期および長期のどちらのばく露においても、組織および羊水の温度は、それぞれ、RF照射をオンにした約40〜50分後にその最大に達した（漸近的に）；スイッチをオフすると、40〜50分以内に、卵内部の温度は初期値に戻った、と報告している。

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研究目的（著者による）

To investigate the relationship between exposure and temperature changes in exposed tissues, without considering biological and medical effects. The extent of the thermic effects of a 1.25 GHz field on chicken embryos at several stages of embryonic development was evaluated.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 1.25 GHz
Modulation type: CW
ばく露時間: 1 to 2 h per day for 21 days
  • 電力密度: 25 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively)
  • 電力密度: 7.5 W/m² minimum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively)
  • 電力密度: 90 W/m² maximum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 10.26 W/kg and 5.67 W/kg respectively)
  • 電力密度: 53 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively)
  • 電力密度: 70 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 7.98 W/kg and 4.41 W/kg respectively)
  • 電力密度: 12.5 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively)
ばく露2: 1.25 GHz
Modulation type: CW
ばく露時間: continuous for 21 days
  • 電力密度: 53 W/m² maximum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively)
  • 電力密度: 12.5 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively)
  • 電力密度: 25 W/m² unspecified (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively)
  • 電力密度: 7.5 W/m² minimum (whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively)

ばく露1

主たる特性
周波数 1.25 GHz
タイプ
  • electromagnetic field
ばく露時間 1 to 2 h per day for 21 days
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
チャンバの詳細 BBS breeding/hatching incubator/ 80 cm high x 60 cm long x 56 cm wide
ばく露装置の詳細 Eggs were placed on a movable plastic rack 10 cm under the aperture of the horn antenna
Additional information Eggs turned automatically around their longitudinal axis once per hour Electric polarization was along the longest egg axis
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 25 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively
電力密度 7.5 W/m² minimum 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively
電力密度 90 W/m² maximum 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 10.26 W/kg and 5.67 W/kg respectively
電力密度 53 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively
電力密度 70 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 7.98 W/kg and 4.41 W/kg respectively
電力密度 12.5 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively

ばく露2

主たる特性
周波数 1.25 GHz
タイプ
  • electromagnetic field
ばく露時間 continuous for 21 days
Modulation
Modulation type CW
ばく露装置
ばく露の発生源／構造
チャンバの詳細 BBS breeding/hatching incubator/ 80 cm high x 60 cm long x 56 cm wide
ばく露装置の詳細 Eggs were placed on a movable plastic rack 10 cm under the apreture of the horn antenna
Additional information Eggs turned automatically around their longitudinal axis once per hour
パラメータ
測定量 値 種別 Method Mass 備考
電力密度 53 W/m² maximum 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 6.04 W/kg and 3.34 W/kg respectively
電力密度 12.5 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 1.43 W/kg and 0.79 W/kg respectively
電力密度 25 W/m² unspecified 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 2.85 W/kg and 1.57 W/kg respectively
電力密度 7.5 W/m² minimum 測定値 - whole body SAR in embryo during day 1-7 and 14-21 of exposure were calculated to be 0.86 W/kg and 0.47 W/kg respectively

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:
  • ばく露中

研究の主なアウトカム（著者による）

Throughout the entire 21 days of embryonic development, the mean temperature increases in the eggs during the exposure were found to be up to 0.25°C for a power flux density of 1.25 mW/cm² and increased to 2.3°C for 9 mW/cm². The field-induced temperature increase was greatest in the first week of incubation and was less pronounced in the last week before hatching. In both the short- and long-term exposures, the temperature of the exposed tissue and the amniotic fluid reached its maximum approximately 40-50 min after the radiofrequency field was switched on.

研究の種別:

研究助成

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