Cellular Effects Following Exposure to Wireless DECT Base Radiation and Presentation of a Device for Their Compensation

Background: Wireless telecommunication sources working with frequencies ranging from 0.9 to 2.5 GHz are still increasing rapidly. Among these are digitally enhanced cordless telecommunication (DECT) phones which have been considered to emit only a weak radiation when an active DECT base and handset are separated from each other. Aim of the Study: Prompted by this background this study investigated the cellular effects of DECT base radiation and its possible compensation by a specially designed device, named memonizerCOMBI Standard A. Materials and Methods: Connective tissue fibroblasts (L-929) were exposed to the radiation of an Original Research Article Dartsch and Dochow; JOCAMR, 3(2): 1-9, 2017; Article no.JOCAMR.33849 2 active commercially available DECT base with a frequency of 1.885 GHz for 24 hours ± memonizer COMBI beneath the incubator. Unexposed cells in another incubator placed with a distance of about 10 m in the same laboratory rooms served as corresponding controls. Cell vitality was checked by enzymatic measurement of the activity of mitochondrial dehydrogenases by XTT. Results: The results clearly demonstrate that exposure to DECT base radiation caused a significantly reduced cell vitality by 47.6 ± 7.4% (mean value ± standard deviation; P = .01; Wilcoxon-Mann-Whitney test). Reduction in cell vitality was accompanied by marked morphological changes in the cells such as intracellular vacuolization, rounding and detachment which are similar to alterations observed during oxidative stress by the presence of reactive oxygen species. Reduction in cell vitality after DECT base radiation exposure was compensated by use of memonizerCOMBI by two-thirds yielding a reduction in cell vitality by only 17.5 ± 8.1% (mean value ± standard deviation; P = .01 vs. exposed cells without memonizer; Wilcoxon-Mann-Whitney test). Conclusions: The results indicate that exposure of cultured connective tissue cells to DECT base radiation at a frequency of 1.885 GHz causes a significantly reduced cell vitality which can be extensively compensated by using a memonizerCOMBI device.


INTRODUCTION
The continuous increase of wireless telecommunication sources, such as mobile phones, digitally enhanced cordless telecommunication (DECT) phones, routers and many others have caused a dramatic increase in environmental levels of electromagnetic radiation [1][2][3][4].All these sources emit radiation in a wide spectrum of frequencies with different characteristics ranging from 0.9 to 2.5 GHz.Although the energy of this type of radiation is weak compared to ionizing radiation, recent research provides strong evidence that electromagnetic radiation is able to affect biological and biochemical processes and might lead to oxidative stress, cell death, cellular dysfunction and even carcinogenesis [see, for instance refs [5][6][7][8][9][10][11].
Due to its world-wide importance with more than 5 billion users [12], mobile phone technology has been extensively investigated for its health effects at the cellular, experimental animal and epidemiological level [see, for instance refs [6,7,[13][14][15][16].Epidemiological and experimental research on DECT base and handset radiation exposure which might be also potentially harmful to millions of people is very limited [17].
Given the limited available data, the objective of the present study was to investigate the effects of radiation emitted from an active DECT base on cultured connective tissue cells with their wide-spread distribution within the body and the use of a newly created device for the compensation of DECT base radiation.

DECT Phone
The active base of a commercially available DECT phone (Gigaset 4010 Classic; Siemens, Germany) was used for the experiments described here.Analysis of the frequency characteristics gave a sharp peak at 1.885 GHz with -46.47 dBm (Fig. 1).

Fig. 1. Analysis of frequency for the active DECT base (Siemens Gigaset 4010 Classic) ranging from 1.87 GHz to 1.90 GHz
The main peak is found at 1.885 GHz with -46.47 dBm

Device for Compensation of DECT Base Radiation
The device which was tested for its potential to compensate DECT base radiation was a memonizerCOMBI Standard A (COT-STD.A).This device is commercially available from memon® bionic instruments GmbH, D-83026 Rosenheim, Germany.

Cell Culture and Test Procedure
The main problem of studies of whole multicellular organisms such as rats, mice, drosophila and others is the complexity of the test systems.There are numerous unknown variables which are difficult to be established.In contrast to these models, cultivation of eukaryotic cells can be standardized and provides the opportunity to vary different factors depending on the experimental needs.
In this present study, cultured connective tissue fibroblasts (cell line L-929; Leibniz-Institut, Deutsche Sammlung für Mikroorganismen und Zellkulturen, Braunschweig, Germany) as a standard cell line for toxicological studies were taken at passages 22 to 50 over a total experimental period of 4 months.Cells were routinely cultivated in the moist atmosphere of an incubator at 37°C and gassed with 5% CO 2 and 95% air to yield a constant pH value.Culture medium was RPMI 1640 with 10% fetal calf serum and standard amounts of penicillin and streptomycin.All cell culture reagents were from GE Healthcare Life Sciences; Freiburg, Germany.
For the tests, cells were seeded from 80 to 90 % confluent mass cultures at a density of 20,000 cells/well into 16 wells in the middle part of a 96 well-plate (200 µL culture medium/well).After 24 hours to ensure cell attachment and metabolization, culture medium was exchanged to 250 µL/well of Leibowitz L-15 medium (Biochrom; Berlin, Germany) containing 10% fetal calf serum and standard amounts of penicillin and streptomycin.This culture medium guarantees a pH value at 7.4 even at normal atmospheric conditions.Plates were transferred to a Cultura M mini incubator and cultivated at 37 ± 1°C without CO 2 -gassing.
The active DECT base was directly placed on the lid of the culture plate and cells were exposed to the DECT base radiation at continuous operation for the next 24 hours.Approximately 10 meters distance in the same laboratory rooms, a second Cultura M mini incubator was taken for the untreated control cells in a 96-well plate at the same cultivation conditions.
After 24 hours of exposure, cell vitality was checked by morphological observation of the cell cultures and by enzymatic activity.For this purpose, cell culture medium was removed and replaced by 120 µL fresh culture medium and 12 µL XTT (Xenometrix AG, Allschwil, Switzerland) and incubated for 120 minutes in the incubator at 37°C.
XTT is the sodium salt of 2,3-bis[2-methoxy-4nitro-5-sulfo-pheny]-2H-tetrazolium-5carboxyanilide and has a yellowish color.Mitochondrial dehydrogenases of viable cells cleave the tetrazolium ring of XTT to yield orange formazan crystals which are soluble in aqueous solutions.The intensity of the resulting orange solution correlates directly with cell vitality and metabolic activity [26,27].
After 120 minutes, optical density was measured as a differential measurement ∆OD = 450 minus 690 nm after a 4 second shaking interval using an ELISA reader (BioTek Slx808).The experiments were performed in 4 independent test series on different days with 14 wells per test.Statistical analysis was done using Wilcoxon-Mann-Whitney test.
In a second series of experiments, the same experimental design as described above was used with the modification that the device for compensation was placed directly beneath the Cultura M mini incubator containing the 96-well plate and the active DECT base.The experiments were performed in 6 independent test series on different days with 14 wells per test.Statistical analysis was done using Wilcoxon-Mann-Whitney test.

RESULTS
The results of all experiments presented here were consistent and reproducible, considering they were conducted within a time period of several months with breaks between the investigation intervals.This demonstrates that this experimental setup has been established successfully and provides data which can be directly compared with each other.
As depicted in Fig. 2, the exposure of connective tissue fibroblasts to the active DECT base for 24 hours caused a reduced cell vitality in all experiments when compared to untreated control cells.When the results of the single experiments are taken together, this reduction in cell vitality was 47.6 ± 7.4% (mean value ± standard deviation) and was statistically different from untreated control cells as checked by Wilcoxon-Mann-Whitney test (P = .01;Fig. 5).The reduced cell vitality after DECT base radiation exposure also resulted in a largely altered morphology of connective tissue fibroblasts (Fig. 3) with Note the marked cell rounding, detachment and intracellular vacuolization in (B) which might be related to oxidative stress.Phase contrast microscopy at an Olympus IX50 inverted microscope equipped with an Olympus 20x Planachromate and an Olympus E-10 digital camera at 4 megapixels intracellular vacuolization and rounding of cells with long cytoplasmic protrusions or even detachment.These changes were irreversible, because cells did not achieve normal cell morphology after another 24 hours of incubation in fresh culture medium and without any further DECT base radiation exposure (not depicted).
When a memonizerCOMBI Standard A was placed beneath the incubator in which cells were exposed to DECT base radiation for 24 hours, the reduction in cell vitality was markedly different from previous experiments without the device.Vitality of connective tissue fibroblasts was reduced now only by 17.5 ± 8.1% (mean value ± standard deviation) which is equivalent to a compensation of unwanted cellular effects of approximately two-thirds (Fig. 4 and Fig. 5).The statistical significance of the summarized values between exposed cells ± memonizerCOMBI Standard A was P = .01confirming that the device was able to reduce cellular effects in a quite effective way.However, there was still a statistical difference of P = .05between untreated control cells and exposed cells with memonizerCOMBI Standard A (Fig. 5).
There is another point which should be mentioned here.It took at least 7 days after installation of the device below the Cultura M mini incubator until its information transfer field had developed and was efficient enough to compensate the unwanted cellular effects of DECT base radiation as presented above.

DISCUSSION
The fact that wireless telecommunication sources might cause unwanted health effects is still under controversial discussion.However, one should also take the different relevant frequencies under consideration which are ranging from 0.9 GHz to 2.5 GHz and might vary from country to country.Although mobile phones have become the main wireless telecommunication source worldwide, wireless DECT phones are still in use in millions of domestic homes and at workplaces.It has been considered that DECT phones emit only a weak and uncritical radiation when an active DECT base and handset are separated from each other.Indeed, this seems to be not the case under the test conditions as presented here.In the tests, the radiation of an active DECT base reduced cell vitality by approximately 50%.
One might argue that an active DECT base for a continuous period of 24 hours and a distance of only some centimeters between cells and DECT base might be not a realistic situation.This may be right, although there are numerous people who have a DECT base nearby and the handset placed on the table nearly every day.Under these circumstances, the cellular effects of an active DECT base become more prominent.However, the cellular effects in terms of morphology and vitality as observed here are in accordance with previous studies on other cell types [28,29].

Each data point given in the diagrams represents the cell vitality in one single well of the appropriate 96-well plate
Oxidative stress is a biochemical condition, which is defined by an imbalance between reactive oxygen species and the body's antioxidant protection.The presented morphological results with an active DECT base at a frequency of 1.885 GHz point to previous findings which described that the generation of reactive oxygen species and the resulting oxidative stress seems to be one of the main mechanisms causing cell death by apoptosis (see, for instance [28][29][30][31].Dasdag and Akdag [32] evaluated in their review available in vitro and in vivo studies carried out on the relation between radiofrequency radiation and oxidative stress.The results of their studies indicated that radiofrequency radiation might be a factor which causes oxidative stress.Quite surprising and unexpected were the results when a memonizerCOMBI Standard A was placed beneath the incubator in which the cells were exposed to DECT base radiation.As shown here in a number of independent experiments, this device is able to compensate the unwanted cellular effects of the radiation by approximately two-thirds.How the memonizerCOMBI Standard A really acts on the cells and reduces the unwanted effects of DECT base radiation is currently unknown and only a subject of speculation.
Further studies are currently undertaken to come to a closer understanding of the mechanisms how this device compensates DECT base radiation.However, many electro sensitive persons report an improvement of their situation when a memonizerCOMBI Standard A is used over a longer period of time.

CONCLUSION
The results indicate that exposure of cultured connective tissue cells to DECT base radiation at a frequency of 1.885 GHz causes a significantly reduced cell vitality which can be greatly compensated by using a memonizerCOMBI device.

CONSENT
It is not applicable.

Fig. 2 .Fig. 3 .
Fig. 2. Original measurements of 4 independent experiments with exposure of connective tissue fibroblasts to the active DECT base for 24 hours (gray circles) in comparison to untreated control cells (black circles)Each data point given in the diagrams represents the cell vitality in one single well of the appropriate 96-well plate

Fig. 5 .
Fig. 5. Summarized presentation of the reduced cell vitality of connective tissue fibroblasts after exposure to DECT base radiation for 24 hours and its compensation by use of a memonizerCombi Standard A device Data represent mean value ± standard deviation of 4 experiments (untreated control vs. DECT base radiation; P = .01;Wilcoxon-Mann-Whitney test) and 6 experiments (untreated control vs. DECT base radiation with memonizer compensation; P = .05;Wilcoxon-Mann-Whitney test) Lixia S, Yao K, Kaijun W, Deqiang L, Huajun H, Xiangwei G, Baohong W, Wei Z, Jianling L, Wei W. Effects of 1.8 GHz radiofrequency field on DNA damage and