Noviembre 2005

More studies examine the blood-brain barrier

Several recent studies have explored the effect of radiofrequency radiation (RFR) on the blood-brain barrier (BBB). Nylund and Leszczynski exposed human endothelial cells to 900 MHz RFR for 1 hour, and reported that this altered the amount of proteins that are used in the supporting structure of cells. They hypothesize that this could have an effect on the BBB.

Kuribayashi and colleagues, however, could not find any evidence of disruption of the blood-brain barrier in young rats after exposure to RFR at 1439 MHz frequency for 90 minute a day, six days per week, for 1 or 2 weeks.

Franke and colleagues previously reported that RFR exposure increased sucrose permeability after exposure of cell cultures to a GSM 1800 field (Schirmacher, 2000). In the present experiment they altered the cell cultures and improved tightness of the blood-brain barrier, so that "barrier properties ...come very close to the low in vivo permeability". They could not find any evidence of increased permeability of the BBB. In another report the same group of authors tested the BBB with a UTMS signal, and again could not find any evidence of increased permeability.

For more, see "Research - Toxicological Experiments - brain function".

Reference: Nylund R, Leszczynski D (2004): Proteomics analysis of human endothelial cell line EA.hy926 after exposure to GSM 900 radiation. Proteomics 4:1359-1365.

Kuribayashi M, Wang J, Fujiwara O, Doi Y, et al. (2005): Lack of effects of 1439 MHz electromagnetic near field exposure on the blood-brain barrier in immature and young rats. Bioelectromagnetics, 26:578-588.

Franke H, Ringelstein EB, Stogbauer F (2005a): Electromagnetic fields (GSM 1800) do not alter blood-brain barrier permeability to sucrose in models in vitro with high barrier tightness. Bioelectromagnetics 26:529-535.

Franke H, Streckert J, Bitz A, Goeke J, et al. (2005b): Effects of universal mobile telecommunications system (UTMS) electromagnetic fields on the blood-brain barrier in vitro. Radiation Research 164:259-269.

RFR exposure does not contribute to ear warmth during a phone call

Some cell phone users have complained warmth in the region of the ear during a call.
Straume (2005) found that the temperature increases to the external ear that occur during a cell phone call are due to the insulation effect of the phone and the electrical power dissipation. Radiofrequency exposure did not contribute significantly to the temperature increase.

For more, see "Research- Clinical - experiments - others - temperature control".

Reference: Straume A, Oftedal G, Johnsson A (2005): Skin temperature increase caused by a mobile phone: A methodological infrared camera study. Bioelectromagnetics 26:510-519.

Correspondence on the radial arm maze studies

In a recent issue of "Bioelectromagnetics", there are responses by Jauchem and by Cassel to a letter from Lai that criticized attempts to replicate his 1994 study on the effects of electromagnetic fields on rats' performance in a radial arm maze. Lai offers a further response.

References: Jauchem JR. Letter to the Editor concerning Lai's letter on "Radial arm maze performance of rats following repeated low level microwave radiation exposure" (Bioelectromagnetics 25:49-57 (2004)). Bioelectromagnetics, 2005;26:525.

Cassel J-C. Letter to the Editor concerning "Radial arm maze performance of rats following repeated low level microwave radiation exposure", by Cobb et al. (BEMS, 2004, 25:49-57) and "Letter to the Editor" by Lai (BEMS, 2005, 26:81). Bioelectromagnetics, 2005;26:526-7.
Lai H. Response to Jauchem and Cassels. Bioelectromagnetics 2005;26:528.

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