To study the influence of high-frequency electromagnetic fields on the intracellular calcium concentration of excitable (isolated heart muscle cells of the guinea pig) and non-excitable cells (T lymphocytes of the Jurkat cell line).
An experiment was divided into three parts: During the first phase the cells were monitored without any field present, during the second phase the cells were usually exposed to the field, and during the third phase a chemical stimulation was carried out, in order to raise the calcium concentration in the cytoplasm of the cells.
| Exposure | Parameters |
|---|---|
|
Exposure 1:
900 MHz
Modulation type:
CW
Exposure duration:
continuous for 500 s
|
|
|
Exposure 2:
900 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 3:
900 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 4:
900 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 5:
900 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 6:
1,300 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 7:
1,800 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 8:
900 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 120 min
|
|
|
Exposure 9:
1,100 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 10:
1,300 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 11:
1,500 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 12:
1,700 MHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
|
Exposure 13:
1,900 GHz
Modulation type:
pulsed
Exposure duration:
continuous for 500 s
|
|
Heart muscle cells and T-Jurkat cells were subjected to an extensive measurement programme with various carrier frequencies (between 900 and 1900 MHz) and pulsation patterns (0, 16, 50, 217 Hz, and 30 kHz). With the heart muscle cells, additional experiments were performed, i.e., long term exposures (120 min) and exposures of depolarized cells (depolarization from -80 mV to -50, -30, and 0 mV).
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | CW |
|---|
| Exposure source | |
|---|---|
| Chamber | The TEM cell was designed to fit on top of the inverted microscope and consisted of two separate parts, i.e. the upper part with the septum (the TEM cell itself), and the rectangular bottom plate containing the 1-cm test chamber for holding the biological material. The bottom of this chamber consisted of a glass coverslip and a 1-mm metal mesh made of 0.05-mm wire and provided shielding while allowing optical observation. A detailed description can be found in the partial report on "Expositionseinrichtungen" [Neibig, 1996]. |
| Setup | The sample volume (200 µl perfusion fluid with cells) in a Plexiglas container was maintained at a constant temperature by an exchange of the fluid preheated to 37 °C and an additional heating fluid running through a circular channel around the sample volume. |
| Sham exposure | A sham exposure was conducted. |
| Additional info | An experimental run consisted of three phases each lasting 500 s. The first phase without any exposure was followed by field or sham exposure. During the third phase a chemical stimulation was performed in order to provoke a response of the cells which served as positive control. |
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 50 % |
| Repetition frequency | 16 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 50 % |
| Repetition frequency | 50 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 14 % |
| Repetition frequency | 217 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Additional info | In one set of experiments, the membrane potential of the heart muscle cells was adjusted to different values (-80 mV, -50, -30, and 0 mV). In the third phase, the membrane potential of the depolarized cells was repolarized to -80 mV. |
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Frequency | 1,300 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 14 % |
| Repetition frequency | 217 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
| Frequency | 1,800 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 14 % |
| Repetition frequency | 217 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Frequency | 900 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 120 min |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 14 % |
| Repetition frequency | 217 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Additional info | In a third set of experiments with heart muscle cells, long-term exposures were tested. The first phase (without field) lasted 5 min and was followed by 120 min of exposure and 25 min of chemical stimulation (positive control). |
| Frequency | 1,100 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
| Frequency | 1,300 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
| Frequency | 1,500 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
| Frequency | 1,700 MHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
| Frequency | 1,900 GHz |
|---|---|
| Type | |
| Charakteristic |
|
| Exposure duration | continuous for 500 s |
| Modulation type | pulsed |
|---|---|
| Duty cycle | 80 % |
| Repetition frequency | 30,000 Hz |
| Pulse type | rectangular |
| Exposure source |
|
|---|---|
| Sham exposure | A sham exposure was conducted. |
| Measurand | Value | Type | Method | Mass | Remarks |
|---|---|---|---|---|---|
| power | 2 W | peak value | measured | - | - |
The data did not give any sign for an influence of weak (athermal) high-frequency electromagnetic fields on the intracellular calcium concentration of cells independently of the carrier frequency and the pulsation pattern.
Experiments with heart cells: The chemical stimulation lead always to an increase in the cytoplasmic calcium concentration indicating that the calcium transport mechansims were working properly. In contrast, the electromagnetic field exposure did not influence the calcium concentration in any case. There was no difference between the sham-exposed and the exposed cells.
Jurkat-cells: The cytoplasmic calcium concentration could not be influenced by the high-frequency field. However, in these cells the cytoplasmic calcium concentration did neither change during chemical stimulation.
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