Schirmacher A, Winters S, Fischer S, Goeke J, et al. (2000)
study used an in vitro model of the blood-brain barrier (BBB).
This model, which consisted of rat brain cells growing in a culture
with pig blood vessel cells, was tested using electron microscopy
and immunocytochemistry, and found to reflect vital properties
of the BBB. The cultures were exposed to 1800 MHz microwave radiation
pulsed at a repetition rate of 217 Hz. The overall average SAR
was 0.3 W/kg, with a maximum value of 0.46 W/kg at any point.
No significant rise in temperature could be detected within the
measurement resolution of about 0.1° C.
The authors conclude that their experiment showed "a definite and reproducible effect of microwave exposure on the physiological properties of the BBB in vitro".