The Effects of Low-level Radiofrequency and Microwave Radiation on Brain Tissue and Animal Behaviour

Blackwell, R. P.; Saunders, Richard D. E.

doi:10.1080/09553008614551211

Cited by 26 publications

(11 citation statements)

References 63 publications

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“…Since the windows often are very narrow, the experimental search for unique combinations of different exposure parameters among the innumerable possibilities is problematic, and it is no wonder that many attempts to reveal the effectiveness windows by probing various combinations of exposure parameters resulted in negative ®ndings [Chou and Guy, 1978;Bush et al, 1981;Liu et al, 1982;Pakhomov et al, 1992Pakhomov et al, , 1995. More information and discussion of window phenomena can be found in specialized reviews on pulsed microwave bioeffects [Blackwell and Saunders, 1986;Postow and Swicord, 1986;Pakhomov and Murphy, 2000].…”

Section: Introductionmentioning

confidence: 98%

Comparison of dose dependences for bioeffects of continuous‐wave and high‐peak power microwave emissions using gel‐suspended cell cultures†

Pakhomov¹,

Gajšek²,

Allen³

et al. 2002

Bioelectromagnetics

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The study compared bioeffects of continuous wave (CW) microwaves and short, extremely high power pulses (EHPP) at the same carrier frequency (9.3 GHz) and average power (1.25 W). The peak transmitted power for EHPP was 250 kW (0.5-micro s pulse width, 10 p.p.s.), producing the E field of 1.57 MV/m in the waveguide. A biological endpoint was the density of yeast cells, achieved after a 6 h growth period in a solid nutrient medium (agarose gel) during EHPP or CW exposure. Owing to power losses in the medium, the specific absorption rate (SAR) ranged from 3.2 kW/kg at the exposed surface of the sample to 0.6 mW/kg at 24 mm depth. Absorption and penetration of EHPP was identical to CW, producing peak SAR values 200 000 times higher than the average SAR, as high as 650 MW/kg at the surface. CW and EHPP exposures produced highly nonuniform but identical heating patterns in exposed samples. Following the exposure, the samples were sliced in a plane perpendicular to the wave propagation, in order to separate cell masses exposed at different SAR levels. Cell density in the slices was determined by nephelometry and compared to unexposed parallel control samples. Cell density was strongly affected by irradiation, and the changes correlated well with the local temperature rise. However, the data revealed no statistically significant difference between CW and EHPP samples across the entire studied range of SAR levels (over six orders of magnitude). A trend (P<0.1) for such a difference was observed in slices that were exposed at a time average SAR of 100 W/kg and higher, which corresponded to peak SAR above 20 MW/kg for the EHPP condition. These numbers could be indicative of a threshold for a specific (not merely thermal) exposure effect if the trend is confirmed by future studies.

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Section: Introductionmentioning

confidence: 98%

Comparison of dose dependences for bioeffects of continuous‐wave and high‐peak power microwave emissions using gel‐suspended cell cultures†

Pakhomov¹,

Gajšek²,

Allen³

et al. 2002

Bioelectromagnetics

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“…A number of published studies have reported enhanced effects of RF fields subjected to modulation in the extremely low frequency (ELF) range on the efflux of radioactively labelled calcium ions from brain tissue (for reviews, see Myers & Ross 1981, Liddle & Blackman 1984, Blackwell & Saunders 1986, Advisory Group on Non-ionizing Radiation 2001). In particular, a modulation frequency-dependent ''window'' (i.e., a narrow range of modulation frequencies over which an effect is observed) has been suggested with a peak around 16 Hz (Bawin & Adey 1976, Blackman et al 1979.…”

Section: Introductionmentioning

confidence: 98%

An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes

Green

Scott

Gwyther

et al. 2005

International Journal of Radiation Biology

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“…Microwave irradiation without hyperthermia did not open the BBB. For a review on the effects of low-level radiofrequency and microwave irradiation on brain tissue refer to Blackwell and Saunders (1986). The data of Sminia et d. (1992) show that an injurious heat dose was required to increase the uptake of cisplatin in the spinal cord.…”

Section: Effects Of Combination Of Hyperthermia Und Chemotherapy On Tmentioning

confidence: 97%

Effect of hyperthermia on the central nervous system: A review

Sminia

Zee

Wondergem

et al. 1994

International Journal of Hyperthermia

113

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Experimental data show that nervous tissue is sensitive to heat. Animal data indicate that the maximum tolerated heat dose after local hyperthermia of the central nervous system (CNS) lies in the range of 40-60 min at 42-42 x 5 degrees C or 10-30 min at 43 degrees C. No conclusions concerning the heat sensitivity of nervous tissue can be derived from clinical studies using localized hyperthermia. The choice whether or not to exceed the critical heat dose, as derived from laboratory studies, in clinical practice is very much dependent on the clinical situation such as the anatomical site and volume of the tissue involved, and prior therapy. Data on clinical application of whole body hyperthermia (WBH) show that nervous tissue can withstand a slightly higher heat dose than after localized heating, which might be the result of developing thermal resistance during treatment. Expression of thermotolerance was observed in the spinal cord of laboratory animals. After WBH in man at a maximum between 40 and 43 degrees C for 6 h-30 min CNS complications were reported, but other complications seemed to be more life-threatening. Most studies indicate that impairment of the CNS after WBH was not due to direct heat injury to the brain or spinal cord, but was secondary as a result of physiological changes. Heat, at least if applied shortly after X-rays, enhances the response of nervous tissue to radiation. Neurotoxicity of chemotherapeutic drugs does not seem to be a limiting complication in hyperthermia if combined with chemotherapy, but only few data are available. The limited clinical experience shows that safe hyperthermic treatment of CNS malignancies or tumours located close to the CNS seems feasible under appropriate technical conditions with adequate thermometry and taking the sensitivity of the surrounding normal nervous tissue into account.

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The Effects of Low-level Radiofrequency and Microwave Radiation on Brain Tissue and Animal Behaviour

Cited by 26 publications

References 63 publications

Comparison of dose dependences for bioeffects of continuous‐wave and high‐peak power microwave emissions using gel‐suspended cell cultures†

Comparison of dose dependences for bioeffects of continuous‐wave and high‐peak power microwave emissions using gel‐suspended cell cultures†

An investigation of the effects of TETRA RF fields on intracellular calcium in neurones and cardiac myocytes

Effect of hyperthermia on the central nervous system: A review

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