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

[オルニチン脱炭酸酵素活性へのマイクロ波の影響におけるコヒーレンス時間の役割] med./bio.

The role of coherence time in the effect of microwaves on ornithine decarboxylase activity.

掲載誌: Bioelectromagnetics 1993; 14 (5): 395-403

この研究は、ELF磁界によるL929線維芽細胞でのオルニチンデカルボキシラーゼ活性増強に必要な最小コヒーレンス時間などを報告している著者が、振幅変調915MHzマイクロ波でも、オルニチンデカルボキシラーゼ活性増強において非常に類似したコヒーレンス時間現象を見出し、そのコヒーレンス効果について、マイクロ波振幅変調周波数を変えて、さらに探求した実験結果を報告している。

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研究目的(acc. to author and editor)

To investigate the effects of extremely low frequency amplitude modulated microwaves on the activity of the ornithine decarboxylase enzyme (catalyses the reaction of ornithine into putrescine and CO2) in dependence of so-called coherence time. Coherence time here is used in the meaning of a defined time interval over which frequency, phase, and amplitude of the field can be reasonably predicted.

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 915 MHz
Modulation type: AM
ばく露時間: continuous for 8 h
ばく露2: 915 MHz
Modulation type: AM
ばく露時間: continuous for 8 h
ばく露3: 915 MHz
Modulation type: AM
ばく露時間: continuous for 2-24 h
ばく露4: 915 MHz
Modulation type: CW
ばく露時間: continuous for 8 h

ばく露1

主たる特性
周波数 915 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 8 h
Modulation
Modulation type AM
Modulation frequency 55–65 Hz
Modulation depth 23 %
Additional information

The modulation signal was periodically switched between 55 and 65 Hz. The operating time for each frequency was selected as a fixed period τ (between 0.1 and 50 s) and a random period Δτ (between 0 and 50 ms).

ばく露装置
ばく露の発生源/構造
チャンバの詳細 A Crawford cell was placed in an incubator chamber maintained at 37°C. The Crawford cell was mounted vertically on a rotary table and provided with an access door to facilitate sample insertion.
ばく露装置の詳細 Two tissue culture flasks (25 cm², 50 ml) were placed end to end on each side of the center conductor parallel to the EF and perpendicular to the direction of propagation. Four control flasks were placed in the same incubator at the same height as the exposed cultures.
Additional information A double stub tuner was used to match the impedance of the loaded Crawford cell. Due to the size of the flasks, the ideal uniform exposure configuration could not be achieved. From 5 to 12 separate experiments were performed for each exposure condition (frequency, and coherence time in random order).
パラメータ
測定量 種別 Method Mass 備考
電力 0.96 W - - - -
電界強度 0.7 V/cm - 計算値 - -
SAR 2.5 W/kg spatial average 測定値 - -

ばく露2

主たる特性
周波数 915 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 8 h
Modulation
Modulation type AM
Modulation frequency 55–65 Hz
Modulation depth 23 %
Additional information

AM at 55, 60, or 65 Hz

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
電力 0.96 W - - - -
電界強度 0.7 V/cm - 計算値 - -
SAR 2.5 W/kg spatial average 測定値 - -

ばく露3

主たる特性
周波数 915 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 2-24 h
Modulation
Modulation type AM
Modulation frequency 60 Hz
Modulation depth 23 %
ばく露装置
ばく露の発生源/構造
  • E1と同じ装置
Additional information SARs of 0.5 W/kg or a modulation index of 60% were also tested.
パラメータ
測定量 種別 Method Mass 備考
電力 0.96 W - - - -
電界強度 0.7 V/cm - 計算値 - -
SAR 2.5 W/kg spatial average 測定値 - -

ばく露4

主たる特性
周波数 915 MHz
タイプ
  • electromagnetic field
特性
  • guided field
ばく露時間 continuous for 8 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
電力 0.96 W - - - -
電界強度 0.7 V/cm - 計算値 - -
SAR 2.5 W/kg spatial average 測定値 - -

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)

The activity of ornithine decarboxylase in cells exposed to unmodulated microwaves was found not to be altered. The enzyme activity was enhanced approximately two-fold in cells exposed to modulated microwaves at all frequencies used but only for coherence times greater than 10 seconds. Up to now the way how amplitude modulated microwaves affect cells still remains unknown.

研究の種別:

研究助成

Replication studies

関連論文