Gauging the strength of power frequency fields against membrane electrical noise

Bier, Martin

doi:10.1002/bem.20148

Cited by 8 publications

(5 citation statements)

References 19 publications

(49 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Avogadro constant N A = 6 × 10 23 molecules/mol (9) Faraday constant F = N A × q e = 9.65 × 10 4 C/mol (10) Dielectric field constant (free space) ε 0 = 8.85 × 10 −12 C/V/m (11) Figure 3. Left: Typical tumor environment characterized by isolated tumor cells surrounded by extracellular water.…”

Section: Application Of Hyperthermiamentioning

confidence: 99%

Non-thermal effects of radiofrequency electromagnetic fields

Wust

Kortüm

Strauß

et al. 2020

Sci Rep

View full text Add to dashboard Cite

We explored the non-thermal effects of radiofrequency (RF) electromagnetic fields and established a theoretical framework to elucidate their electrophysiological mechanisms. In experiments, we used a preclinical treatment device to treat the human colon cancer cell lines HT-29 and SW480 with either water bath heating (WB-HT) or 13.56 MHz RF hyperthermia (RF-HT) at 42 °C for 60 min and analyzed the proliferation and clonogenicity. We elaborated an electrical model for cell membranes and ion channels and estimated the resulting ion fluxes. The results showed that, for both cell lines, using RF-HT significantly reduced proliferation and clonogenicity compared to WB-HT. According to our model, the RF electric field component was rectified and smoothed in the direction of the channel, which resulted in a DC voltage of ~ 1 µV. This may induce ion fluxes that can potentially cause relevant disequilibrium of most ions. Therefore, RF-HT creates additional non-thermal effects in association with significant ion fluxes. Increasing the understanding of these effects can help improve cancer therapy. Electromagnetic fields (EMF) are generally believed to have no relevant non-thermal effects on cells, tissues, and living organisms 1,2. Only EMF with an excessive strength of > 1.000 kV/m exhibits non-thermal membrane effects such as electroporation 3 or bactericidal microwave exposure 4. Recently, non-thermal effects have been clinically exploited with the tumor-treating field method 5,6 , which applies an EMF at radio frequencies (RF) of 100-300 kHz with a moderate strength of 100-150 V/m. The scientific community considers the risk of such moderate-strength RF-EMF to be negligible, at least with respect to potential hazards caused by powerlines or mobile phones 7-11. Nevertheless, some unresolved observations remain 12,13 , and further research is still recommended 14. However, further specific investigations are only rarely performed because the mechanisms of non-thermal effects remain unknown 15. Oncologists have applied RF technology with similar EMF levels of 200 V/m to cancer treatment using either capacitive (8-30 MHz) or radiative (70-120 MHz) techniques 16. The temperature increase is regarded as the major working mechanism 17. Preclinical data for water bath hyperthermia (WB-HT) have indicated that a temperature of greater than 42 °C is required 18. However, this is rarely achieved in clinical practice, and a temperature achieved in 90% of the target (T 90) of only 39.5-40.5 °C has been correlated with effectiveness 19. Meanwhile, a series of positive randomized trials has shown that RF hyperthermia (RF-HT) improves the effectiveness of radiotherapy or radio-chemotherapy for cervical cancer 20-22. In contrast, extreme whole-body hyperthermia, as the clinical counterpart of WB-HT, using temperatures of ≥ 42 °C has proved to be less effective leading to disappointing results in cancer therapy 23. This indicates that non-thermal effects of RF-EMF do exist. Preclinical studies with animal tumors and cell suspensions 24-26...

show abstract

Section: Application Of Hyperthermiamentioning

confidence: 99%

Non-thermal effects of radiofrequency electromagnetic fields

Wust

Kortüm

Strauß

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…50 or 60 Hz) may be insuffi cient to mask the effect of external applied fi elds thus allowing the small internal fi elds that result from the relatively high conductivity of human tissue to be suffi cient just across membranes. There have been both supporters (Vincze et al, 2005 ;Bier, 2005) of this observation albeit with a different interpretation of the data, and critics such as Adair (2003) , who felt the case was still a speculation and an oversimplifi cation. The importance of these arguments is that when extended to radiofrequency and microwaves, since the higher frequencies (above a few kilohertz) are not 'biologically' active, an additional mechanism becomes essential.…”

Section: Power Frequencymentioning

confidence: 83%

Cognitive Effects of Electromagnetic Fields in Humans

Preece

2009

Advances in Electromagnetic Fields in Living Systems

View full text Add to dashboard Cite

Electromagnetic fi elds interact with human tissue in a number of ways, depending on power level and frequency, and have been long suspected by some to give rise to harmful effects. In particular, the use of a mobile phone against the head has aroused suspicions of various cognitive effects. Accordingly, there have been a large number of studies of behavioural effects from ELF, RF and microwave exposure, mostly as provocation experiments. This chapter discusses the ways and means of doing this, the confusion of physiological effects variously observed and the problem of inconsistency of results. In animal studies, exposure levels have been suffi cient to elicit responses, which largely appear to be related to heating effects, whereas similar studies are not ethically easy in humans. Accordingly, many of the studies have sought to explore non-thermal responses, mediated either through induced currents in neurological tissue or biochemical responses directly in cells. Effects reported for ELF tend to be dissimilar to those for RF and this may be more to do with the physical interaction with tissue than anything more fundamental. It is the possible existence of non-thermal effects that has largely been considered here and also the problem of studies in children who have been urged to restrain mobile phone use. Some important consequences have been observed such as the effect of phone use on driving, but largely the conclusion of detailed provocation studies is that short term or acute exposure to ELF or RF within the established guidelines may not be a hazard to humans, which suggests that the increasing use of RF technology may not itself be harmful.

show abstract

“…Vincze et al [2005] suggested that heating of the extracellular matrix by external fields might conceivably lead to diffusion gradients having biological significance, and Bier [2005] pointed out that the nonequilibrium nature of membrane proteins such as ion pumps may enable them to ''capture'' electromagnetic energy to perform work that is metabolically significant.…”

Section: Discussionmentioning

confidence: 99%

New theoretical treatment of ion resonance phenomena

Vincze

Szász

Liboff

2008

Bioelectromagnetics

View full text Add to dashboard Cite

Despite experimental evidence supporting ICR-like interactions in biological systems, to date there is no reasonable theoretical explanation for this phenomenon. The parametric resonance approach introduced by Lednev has enjoyed limited success in predicting the response as a function of the ratio of AC magnetic intensity to that of the DC field, explaining the results in terms of magnetically induced changes in the transition probability of calcium binding states. In the present work, we derive an expression for the velocity of a damped ion with arbitrary q/m under the influence of the Lorentz force. Series solutions to the differential equations reveal transient responses as well as resonance-like terms. One fascinating result is that the expressions for ionic drift velocity include a somewhat similar Bessel function dependence as was previously obtained for the transition probability in parametric resonance. However, in the present work, not only is there an explicit effect due to damping, but the previous Bessel dependence now occurs as a subset of a more general solution, including not only the magnetic field AC/DC ratio as an independent variable, but also the ratio of the cyclotronic frequency Omega to the applied AC frequency omega. In effect, this removes the necessity to explain the ICR interaction as stemming from ion-protein binding sites. We hypothesize that the selectively enhanced drift velocity predicted in this model can explain ICR-like phenomena as resulting from increased interaction probabilities in the vicinity of ion channel gates.

show abstract

Gauging the strength of power frequency fields against membrane electrical noise

Cited by 8 publications

References 19 publications

Non-thermal effects of radiofrequency electromagnetic fields

Non-thermal effects of radiofrequency electromagnetic fields

Cognitive Effects of Electromagnetic Fields in Humans

New theoretical treatment of ion resonance phenomena

Contact Info

Product

Resources

About