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Abstracts (Zusammenfassungen wichtiger Experimente) |
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Human Experimental Studies - Cognitive Function |
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Preece (1999) examined cognitive function. Of fifteen different tests on volunteers exposed to a 915 MHz signal from a phone model, one test showed results that were marginally different in the exposed compared with the controls. The authors speculated that the effect might be due to a localized heating effect. Koivisto (1999) volunteers exposed to RF fields at 902 MHz had faster response times in 3 out of a total of 12 tasks. In another study, these authors (2000) found that exposure to 902 MHz was associated with accelerated performance of memory tasks by their study subjects. However, the authors did not think that the results were of any practical significance. A slight temperature rise in brain tissue was again suggested as a possible mechanism. Another study by Kolodynski (1996) discusses cognitive function in schoolchildren living in the area of a radio location station, in which the radiofrequencies used are very different from that used in mobile phones References:
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| Quelle: http://www.wirc.org/research/experimental/cognitive.shtml | |
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Title Author French and colleagues hypothesize that exposure to mobile phones might induce or promote cancer via the heat shock response. They point out that the cellular response is characterized by the formation of heat shock proteins (HSPs), which protect cells against damage produced by stress. They cite evidence that HSPs can also play a role in cancer induction or promotion, though they state that there is debate as to whether the association with cancer is causal or correlative. The authors suggest that recurrent exposure to frequent mobile phone use could lead to chronic expression of HSPs in the brain tissue of users and that this in turn might induce or promote cancer. They state that this hypothetical mechanism should be tested experimentally. http://www.wirc.org/research/laboratory/french.shtml |
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Title Author This study, reported in Nature, suggests that prolonged exposure to low-intensity microwave fields may produce biological effects that are non-thermal. The authors found that the microwave fields induced heat-shock responses in the soil nematode Caenorhabditis elegans. The worms were exposed overnight to continuous-wave microwave radiation at 750 MHz. The calculated SAR was 0.001W/kg. The presence of heat-shock proteins (HSPs) was deduced from measurement of chemicals that act as "reporter products". The authors present evidence that these responses are non-thermal. Mechanisms for the heat-stress response "could include microwave disruption of the weak bonds that maintain the active folded forms of proteins; enhanced production of reactive oxygen species; or interference with cell-signaling pathways that affect HSP induction". They suggest that "because of the universality of the heat-shock response, a similar non-thermal induction might also occur in human tissues exposed to microwaves, a possibility that needs investigation". http://www.wirc.org/research/laboratory/depomerai.shtml |
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Title Electromagnetic fields (1.8 GHz) increase the permeability to sucrose of the blood-brain barrier in vitro. Journal Bioelectromagnetics 21:338-345. Authors This
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". http://www.wirc.org/research/laboratory/schirmacher.shtml
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http://www.wirc.org/research/laboratory/tattersal.shtml Authors This study explored the effect of 700 MHz continuous wave RF fields at low intensity on the electrical activity in slices of rat brain from the hippocampus area. The maximum field intensity was calculated to produce a SAR between 0.0016 and 0.0044 W/kg. Changes were noted in the electrical activity of the rat brain slices. At low intensities, the predominant effect was a potentiation of the amplitude of the population spike, but higher intensities could produce either increases or decreases. These results were seen in the absence of detectable temperature change. The authors state that the hippocampus is important in spatial learning and memory processes, and that the changes in electrical excitability may be consistent with reported behavioural effects of RF fields. http://www.wirc.org/research/laboratory/tattersal.shtml
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| Mobilfunkstrahlung senkt das Geburtsgewicht von Ratten | |
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Authors Twelve female rats were exposed to 890 - 915 MHz, modulation frequency 217 Hz, during pregnancy. The exposure was for 1 minute on three occasions during a two-hour period each day. The exposed rats were compared with sham-exposed animals and with male rats that were also exposed for 1 month. The number of offspring per pregnant rat and the birth weight of offspring in the sham and exposed groups were measured. Blood parameters of all male rats and six female rats from the exposed and sham groups were examined immediately after the last exposure. The offspring of the remaining female rats (six in each group) continued to be observed for weight gain. Later these same rats were impregnated to determine the birth weight and white blood counts of the second-generation offspring. None of the blood parameters was significantly altered in any of the generations of rats. The average number of offspring per pregnant rat showed no difference between exposed and sham groups. The birth weight of the offspring in the exposed group was significantly lower than the sham group This weight decrease was temporary and the animals had normal weight by 3 months. The authors felt that the weight decrease could be due either to the radiation or a nonspecific stress reaction.
http://www.wirc.org/research/laboratory/dasdag.shtml
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RF
radiation associated with chromosomal changes in mice
Sykes and colleagues from Flinders University in South Australia report on the effects on mice of exposure to 4W/kg pulsed 900 MHz radiation for 30 minutes daily. They examined the frequency of spontaneous intrachromosomal recombination events in the spleen of mice exposed to the radiation. There was no significant difference between exposed mice and controls in those exposed for 1 or 5 days, but there was a significant reduction in the recombination frequency in the 25-day group. A similar reduction can be seen with proven genotoxic agents, so that this may not be a beneficial event. The authors state that the number of animals in each treatment group was small, and replication of the experiment with a larger number is required. More details of this can be found in "Laboratory Experiments - cancer studies". Reference:
Sykes PJ, McCallum BD, Hooker AM (2001): Effect of exposure to 900 MHz
radiofrequency radiation on intrachromosomal recombination in pKZ1 mice.
Radiation Research 156:495-502.
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Authors Preece and his colleagues did a study that tested the effect of exposure to RF radiation at cell phone frequency on brain function. They tested two groups of 18 subjects each. The subjects wore a headset-mounted physical model of a phone, which was placed in the normal position with the antenna situated adjacent to the left side of the head. Three conditions were used - the phone was not activated; there was a 915 MHz signal like an analog signal; and there was a 915 MHz signal which simulated a digital signal. The subjects did 15 different tests of performance. There were four different categories - accuracy on memory tests, speed on memory tests, accuracy on reaction/attention tests, and speed on reaction/attention tests. In both groups the only test affected was the choice reaction time, which involved hitting a "yes" or "no" button as quickly as possible after the corresponding word flashed on a computer screen. The analog test had a mean time of 373.4 mseconds, compared with 384.4 mseconds for digital exposure, and 388.1 mseconds for the controls. There were no significant changes in word, number or picture recall, or in spatial memory. The results could be due to a chance finding because of multiple testing - the more tests that are analysed, the greater the statistical probability of a spurious finding. However, the results were similar in each of the 2 groups tested, making it less likely that the findings were due to chance. The authors suggested that the decreased reaction time might be due to an effect on the angular gyrus, which is an area of the brain lying directly beneath the antenna position. This gyrus connects the visual and speech centres. Preece speculated that the effect was due to mild localised heating, which could cause expansion of the blood vessels and improved oxygenation in the area. The authors point out that their findings are "near, but not at, worst case conditions" - that is, the worst situation that can arise with phone use in respect of power produced.
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