Study type: Medical/biological study (experimental study)

Effects of 900-MHz Radio Frequencies on the Chemotaxis of Human Neutrophils in Vitro med./bio.

By: Aly AA, Cheema MI, Tambawala M, Laterza R, Zhou E, Rathnabharathi K, Barnes FS
Published in: IEEE Trans Biomed Eng 2008; 55 (2): 795-797
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Aim of study (acc. to author)

To study the effects of radiofrequency fields on the ability of human neutrophils to follow concentration gradients of cyclic AMP (chemotaxis).

Background/further details

Cell's ability to move depends on the type of leukocyte and its age, the amount of anti-coagulant used, and other unknown variables in the condition of the donors. Blood was drawn of 8 students. The effect of different temperatures (22°C - 43°C) was also studied.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Exposure duration: continuous for about 15 min

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Charakteristic
  • guided field
Exposure duration continuous for about 15 min
Exposure setup
Exposure source
Chamber A drop of fluid containing neutrophils was covered with a cover slip to create a layer about 15 µm thick. The cover slip was sealed with Vaseline around the edges to reduce the effects of pressure, temperature, and vibration on the movement of the leukocyte cells and to prevent the sample from drying out.
Setup The slide was placed for about 15 min on the microscope stage heated to the desired temperature, thus allowing it to reach steady state.
Additional info The temperature was increased in a series of experiments by one degree from 22 °C to 43 °C both with and without RF exposure. The motion of the exposed cells was observed for about 15 min before and for about 15 min after applying the RF radiation.
Parameters
Measurand Value Type Method Mass Remarks
power 88.4 µW - calculated - -
electric field strength 0.392 V/m - calculated - -
Additional parameter details

The heater had no measurable effect on the RF field pattern, and the 60-Hz fields were much less than 1 µT.

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Time of investigation:
  • before exposure
  • during exposure
  • after exposure

Main outcome of study (acc. to author)

The speed of the neutrophils increased with increasing temperatures from 35°C to 40°C where it peaked and then decreased above 40°C without radiofrequency exposure.
Under 900 MHz radiofrequency field exposure, the speed increased above the value observed at the same temperature, and the maximum speed exceeded the measured value at any temperature by approximately 50%. The calculated temperature change resulting from the radiofrequency exposure was less than one microdegree.
Upon radiofrequency exposure the neutrophils moved perpendicular to the direction along the cAMP gradient and to the applied electrical fields. Without radiofrequency these cells moved toward the cAMP stripe.
The authors conclude that the effects of radiofrequency exposure on neutrophil chemotaxis should be considered for further exploration in larger and more controlled studies.

Study character:

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