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

[ミオシンL鎖リン酸化変調は磁界に依存する 2 実験性] med./bio.

Myosin Light Chain Modification Depending on Magnetic Fields: II. Experimental

著者: Markov MS
掲載誌: Electromagn Biol Med 2004; 23 (2): 125-140
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この研究は、無細胞調整物のCa 2+-カルモジュリン依存性ミオシン軽鎖（L鎖）のリン酸化に対する弱い磁界の影響を調べた。この無細胞酵素系はよく研究された生化学系であり、イオン結合に依存するようである。この無細胞系の磁界に対する感受性を調べるために、パルス化無線周波（PRF）電磁界、脈動性磁界、勾配磁界（磁気治療器MAGNA BLOCからの磁界）、および一様静磁界（ヘルムホルツコイル）を用いた実験を行なった。これらの様々な磁界は、イオン-タンパク質相互作用を調節することによって、この無細胞酵素系に影響を与えるようである、と報告している。

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研究目的（著者による）

To study the possibility that ion-protein interactions can be affected by magnetic fields with various frequencies and magnetic flux densities. Specifically, Ca2+-calmodulin-dependent myosin phosphorylation, in a cell-free preparation is examined from the viewpoint of searching for mechanisms of action and studying the effectiveness of various magnetic field signals used clinically.

詳細情報

The Ca2+-calmodulin-dependent myosin light chain phosphorylation is a well-studied biochemical enzyme system, which appears to depend upon ion binding.
The reaction was initiated by adding 32P ATP to the medium.
One of the experiments (Field 1) was performed to replicate a previous study (Shuvalova, L.A., Ostrovskayam M.V., Sosunov, E.A., Lednev, V.V. (1991). Weak magnetic fields tuned to the parametric resonance condition change the rate of calcium-calmodulin dependent myosin phosphorylation. Reports of the Academy of Sciences. USSR 317:227-231).

影響評価項目

ばく露

ばく露 パラメータ
ばく露1: 8–20 Hz
ばく露時間: continuous for 5 min
Simultaneously exposed to AC and DC magnetic fields as well as exposure to AC and DC magnetic fields separately.
ばく露2:
  • DC/static
ばく露時間: continuous for 5 min
DC magnetic fields in ambient range
  • 磁束密度: 10 µT minimum (20 µT, 30 µT, 40 µT, 50 µT, 60 µT, 70 µT, 80 µT, 90 µT, 100 µT, 120 µT, 130 µT, 140 µT, 150 µT, 160 µT, 170 µT and 180 µT)
ばく露3:
  • DC/static
ばく露時間: continuous for 5 min
static magnetic field
  • 磁束密度: 5 mT minimum (10 mT, 15 mT, 20 mT, 25 mT, 30 mT, 35 mT, 40 mT, 45 mT, 50 mT and 55 mT)
ばく露4: 27 MHz
Modulation type: pulsed
ばく露時間: continuous for 5 min
pulsed radiofrequency field
ばく露5: 80–180 Hz
ばく露時間: continuous for 5 min
therapeutic electromagnetic field
  • 磁束密度: 5 mT unspecified (10 mT, 15 mT, 20 mT and 25 mT)
ばく露6:
  • DC/static
ばく露時間: continuous for 5 min
gradient magnetic field
-

ばく露1

主たる特性
周波数 8–20 Hz
タイプ
  • magnetic field
波形
  • sinusoidal
ばく露時間 continuous for 5 min
Additional information Simultaneously exposed to AC and DC magnetic fields as well as exposure to AC and DC magnetic fields separately.
Additional information Reference article: Shuvalova, L.A., Ostrovskayam M.V., Sosunov, E.A., Lednev, V.V. (1991). Weak magnetic fields tuned to the parametric resonance condition change the rate of calcium-calmodulin dependent myosin phosphorylation. Reports of the Academy of Sciences. USSR 317:227-231.
ばく露装置
ばく露の発生源／構造
チャンバの詳細 Special designed Plexiglas chamber maintained at 37°C.
ばく露装置の詳細 Two orthogonal Helmholtz pairs of square coils were used to apply vertical and horizontal DC magnetic fields and third pair of circular Helmholtz coils was mounted horizontally to apply AC field. The exposure volume was 100 µL of samples poured in Eppendorf tubes.
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 20.9 µT effective value 測定値 - -

ばく露2

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 continuous for 5 min
Additional information DC magnetic fields in ambient range
ばく露装置
ばく露の発生源／構造
  • E1と同じ装置
ばく露装置の詳細 Same set-up as described in E1 but the tube was placed in a µ-metal box
Additional information The magnetic fields were applied alternatively in the vertical and horizontal directions inside the shield.
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 10 µT minimum 測定値 - 20 µT, 30 µT, 40 µT, 50 µT, 60 µT, 70 µT, 80 µT, 90 µT, 100 µT, 120 µT, 130 µT, 140 µT, 150 µT, 160 µT, 170 µT and 180 µT

ばく露3

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 continuous for 5 min
Additional information static magnetic field
Additional information Reference article: Markov, M.S. (2000). Magnetic and electromagnetic fields- a new frontier in clinical biology and medicine. Millennium International Workshop on Biological Effects of Electromagnetic Fields. Crete, Greece, 365-372, ISBN # 960-86733-0-5.
ばく露装置
ばく露の発生源／構造
  • two 15 x 10 x 2.5 cm³ ceramic NdFeB magnets
チャンバの詳細 Same as in E1.
ばく露装置の詳細 The magnets were configured with the opposite poles facing one another. One magnet was kept stationary while the other one was moved towards the first ones direction to get different magnetic fields.
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 5 mT minimum 測定値 - 10 mT, 15 mT, 20 mT, 25 mT, 30 mT, 35 mT, 40 mT, 45 mT, 50 mT and 55 mT

ばく露4

主たる特性
周波数 27 MHz
ばく露時間 continuous for 5 min
Additional information pulsed radiofrequency field
Additional information Reference article: Markov, M.S., Muesham, D.J., Pilla, A.A. (1994 c). Modulation of cell free myosin phosphorylation with pulsed radio frequency electromagnetic fields. In: Allen, M.J., Cleary, S.F., Sowers, A.E., eds. Charge and Field effects in Biosystems 4. World Scientific, pp- 274-288.
Modulation
Modulation type pulsed
Additional information

pulsed signals consisted of 65 µs burst. The following pulses per seconds were applied: 100, 200, 300, 400, 500 and 600 pulses/sec.
ばく露装置
ばく露の発生源／構造
  • 20 cm diameter pancake coil within a 8 cm high drum applicator
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 160 µT effective value 測定値 - -
磁束密度 200 µT effective value 測定値 - -

ばく露5

主たる特性
周波数 80–180 Hz
タイプ
  • magnetic field
波形
  • pulsed
ばく露時間 continuous for 5 min
Additional information therapeutic electromagnetic field
Additional information Therapeutic electromagnetic field applied at 80 pulses/sec, 100 pulses/sec, 120 pulses/sec, 140 pulses/sec, 160 pulses/sec and 180 pulses/sec.
Modulation
Modulation type cf. additional information
Additional information

half sine wave pulsating signals were applied.
ばく露装置
ばく露の発生源／構造
  • ellipsoidal coil, 55 cm outer diameter and 36 cm lower diameter
パラメータ
測定量 値 種別 Method Mass 備考
磁束密度 5 mT unspecified 測定値 - 10 mT, 15 mT, 20 mT and 25 mT

ばく露6

主たる特性
周波数
  • DC/static
タイプ
  • magnetic field
ばく露時間 continuous for 5 min
Additional information gradient magnetic field
ばく露装置
ばく露の発生源／構造
  • MagnaBloc device
ばく露装置の詳細 Samples were positioned at a distance of 0, 5, 10 and 15 mm from the device.
Additional information MagnaBloc device consisting of 4 NdFeB permanent magnets arranged with alternative polarity in a 2 x 2 array.
パラメータ

No parameters are specified for this exposure.

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 cell-free myosin phosphorylation model system is sensitive to a wide range of magnetic fields that differ in magnetic flux density, repetition rate, and frequency. It appears that the key target is in the binding of the calcium ion to the existing binding sites in the calmodulin structure. Except for the ambient range DC signals, all other signals initiate "resonance"- or "window"-like responses. Therefore, myosin phosphorylation assay may be tool for examining the "window hypothesis".

研究の種別:

研究助成

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