Intensity- and frequency-dependent effects of microwaves on cell growth rates

Grundler, W.

doi:10.1016/0022-0728(92)85129-q

Cited by 11 publications

(19 citation statements)

References 5 publications

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“…7). As mentioned earlier, data about effects of radiofrequency fields on plants are rare, but our results are in agreement with results of animal and cell studies that suggest the effects of radiofrequency fields are frequency dependent and are not linear over the whole field intensity spectrum [Grundler, 1992]. The exposure to 9.575 GHz modulated with square waves of different pulse repetition frequencies induced frequency dependent biological effects in Anabaena dolilum while different microwave frequencies in continuous waves and modulated modes produced significantly different physiological effects on the alga Nostoc muscorum [Banik et al, 2003].…”

Section: Discussionsupporting

confidence: 95%

Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity

Tkalec

Malarić

Pevalek-Kozlina

2005

Bioelectromagnetics

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Increased use of radio and microwave frequencies requires investigations of their effects on living organisms. Duckweed (Lemna minor L.) has been commonly used as a model plant for environmental monitoring. In the present study, duckweed growth and peroxidase activity was evaluated after exposure in a Gigahertz Transversal Electromagnetic (GTEM) cell to electric fields of frequencies 400, 900, and 1900 MHz. The growth of plants exposed for 2 h to the 23 V/m electric field of 900 MHz significantly decreased in comparison with the control, while an electric field of the same strength but at 400 MHz did not have such effect. A modulated field at 900 MHz strongly inhibited the growth, while at 400 MHz modulation did not influence the growth significantly. At both frequencies a longer exposure mostly decreased the growth and the highest electric field (390 V/m) strongly inhibited the growth. Exposure of plants to lower field strength (10 V/m) for 14 h caused significant decrease at 400 and 1900 MHz while 900 MHz did not influence the growth. Peroxidase activity in exposed plants varied, depending on the exposure characteristics. Observed changes were mostly small, except in plants exposed for 2 h to 41 V/m at 900 MHz where a significant increase (41%) was found. Our results suggest that investigated electromagnetic fields (EMFs) might influence plant growth and, to some extent, peroxidase activity. However, the effects of EMFs strongly depended on the characteristics of the field exposure.

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Section: Discussionsupporting

confidence: 95%

Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity

Tkalec

Malarić

Pevalek-Kozlina

2005

Bioelectromagnetics

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“…Each cell line appears to have specific field strengths, modulations, frequencies and exposure durations that will result in a biophysical interaction with that RF field (Ivaschuk et al, 1997;Mashevich et al, 2003). This observation is particularly supported by the earlier work of Grundler (1992) upon yeast cells. At higher field intensities (10 mW/cm 2 ), yeast cell growth rates were markedly decreased when exposed to a microwave field only within a narrow frequency window, between 41,690 and 41,705 MHz.…”

Section: The Impact Of Rf-emfs On Cell Viability and Apoptosismentioning

confidence: 66%

An in vitro study of the effects of exposure to a GSM signal in two human cell lines: Monocytic U937 and neuroblastoma SK-N-SH

Gurisik

Warton

Martin

et al. 2006

Cell Biology International

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The use of mobile phones is increasing, which also increases the population's exposure to global system of mobile communications (GSM) signals. Questions of safety and possible biological effects are of concern and to date, remain largely unanswered. In order to examine possible biological effects of a GSM-like signal at a cellular level, we exposed two human cell lines (one of neuronal (SK-N-SH) and the other of monocytoid (U937) origin) to a 900 MHz RF signal, pulsed at 217 Hz, producing a specific absorption rate (SAR) of 0.2 W/kg. Putative effects were assessed by comparing radiofrequency-exposed cells to sham-exposed cells using a variety of assay techniques. For the cell line SK-N-SH, effects were specifically assessed by gene microarray, followed by real-time PCR of the genes of interest, Western blot analysis was used to measure heat shock protein levels, and flow cytometry to measure cell cycle distributions and apoptosis. Effects of radiofrequency on the cell line U937 were assessed by cell viability and cell cycle analysis. From our study of these two cell lines, we found no significant difference between sham-exposed versus radiofrequency-exposed cells in any of the assays or conditions examined.

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“…As a matter of fact, there is not even a sustainable hypothesis for biological effects and the involvement of demodulation as a consequence of weak narrow band phase or frequency shift keying signals in the body. In some publications the authors observed biological effects like an increased efflux of calcium in the neurons, change in electroencephalogram (EEG), or alteration in the growth characteristics of the cells at a particular frequency and a certain individual modulation (e.g., Adey 1980;Bawin et al 1975;Grundler 1992;Keilmann and Kell 1983). These effects were explained by so-called frequency windows and other theories.…”

Section: Introductionmentioning

confidence: 97%

Demodulation in Tissue, the Relevant Parameters and the Implications for Limiting Exposure

Silny

2007

Health Physics

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In the biomedical literature there are a number of reports that speculate about possible effects in the body due to the demodulation of electromagnetic fields. However, only few interactions in amplitude-modulated or even pulse-modulated electromagnetic waves are fundamentally plausible and have been demonstrated to occur in humans. The following observations fall into this specific category: thermal effects of amplitude- or pulse-modulated microwaves; demodulation of amplitude- or pulse-modulated electromagnetic waves in cell membranes; and demodulation of amplitude- or pulse-modulated electromagnetic fields in the electronics of implants such as cardiac pacemakers or cardioverter defibrillators. The possible consequences of these effects for the organism, their probability of occurrence in everyday life field conditions, and, consequently, the implications for limiting exposure are very different. Microwave hearing is a harmless effect which is perceived by humans only in strong fields with high peak power densities of more than 100 mW cm(-2). In normal residential or occupational environments the peak power density of even the strongest microwave sources is only around 1 mW cm(-2). Demodulation of pulse-modulated electromagnetic fields in the cell membranes decreases the stimulation threshold of nerves and muscles and can introduce numerous adverse effects ranging from perception of pain to dangerous cardiac fibrillations. The stimulation and demodulation effects are restricted to carrier frequencies up to several MHz. In experiments with 900 and 1,800 MHz packets with lengths of up to 100 ms and applied powers of up to 100 W, neither a direct stimulation of superficial nerves and muscles nor the conditioning of an electrical current stimulus could be confirmed. Pulse-modulated electromagnetic waves are demodulated in the electronic circuits of implants and can inhibit cardiac pacemakers and introduce cardiac arrest in this way. The highest sensitivity results from repetition rates of pulses below 100 Hz. The preceding two implications should be considered in the elaboration of new general guidelines limiting the exposure for healthy as well as for sick persons in the future.

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Intensity- and frequency-dependent effects of microwaves on cell growth rates

Cited by 11 publications

References 5 publications

Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity

Influence of 400, 900, and 1900 MHz electromagnetic fields on Lemna minor growth and peroxidase activity

An in vitro study of the effects of exposure to a GSM signal in two human cell lines: Monocytic U937 and neuroblastoma SK-N-SH

Demodulation in Tissue, the Relevant Parameters and the Implications for Limiting Exposure

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