Physiological responses of Plantago media to electromagnetic field of power-line frequency (50 Hz)

Experimental evidence is presented that continuous exposure of hoary plantain (Plantago media L.) seedlings to the electromagnetic field (EMF) of power-line frequency may disturb physiological, biochemical, and cytological characteristics of these plants. The increase in EMF strength in the range from 230 to 1800 V/m (350–2000 nT) was found to reduce the percentage of seed germination, the rate of cell division, and the rates of DNA and protein biosyntheses in tissues of 8-day-old seedlings. The action of EMF with the strength of 500–1000 V/m (800–1150 nT) stimulated root growth, elevated the content of malondialdehyde and low-molecular antioxidants, and enhanced the activity of superoxide dismutase. Direct correlation was revealed between lipid peroxidation rates and the activity of cellular antioxidant defense system. The wavelike changes in the content of photosynthetic pigments were observed in plantain seedlings exposed to EMF of various strengths.     

Spindle disturbances in human-hamster hybrid (A(L) ) cells induced by the electrical component of the mobile communication frequency range signal

The production of spindle disturbances in a human–hamster hybrid (A_L) cell line by an electromagnetic field (EMF) with field strength of 90 V/m at a frequency of 900 MHz was studied in greater detail. The experimental setup presented allows investigating whether either the electrical (E) and/or the magnetic (H) field component of EMF can be associated with the effectiveness of the spindle‐disturbing potential. Therefore, both field components of a transversal electromagnetic field (TEM) wave have been separated during exposure of the biological system. This procedure should give more insight on understanding the underlying mechanisms of non‐thermal effects of EMF. A statistical comparison of the proportions of the fractions of ana‐ and telophases with spindle disturbances, obtained for five different exposure conditions with respect to unexposed controls (sham condition), showed that only cells exposed to the H‐field component of the EMF were not different from the control. Therefore, the results of the present study indicate that an exposure of cells to EMF at E‐field strengths of 45 and 90 V/m, as well as to the separated E component of the EMF, induces significant spindle disturbances in ana‐ and telophases of the cell cycle. Bioelectromagnetics 32:291–301, 2011. © 2010 Wiley‐Liss, Inc.     

Long-term effects of 60-Hz electric vs. magnetic fields on IL-1 and IL-2 activity in sheep

This study was designed to assess the effect of exposure to long-term extremely low-frequency electric and magnetic fields (ELF-EMF) from a 500 kV transmission line on IL-1 and IL-2 activity in sheep. The primary hypothesis was that the reduction in IL-1 activity observed in our two previous short-term studies (10 months) was due to EMF exposure from this transmission line. To repeat and expand these studies and to characterize the components of EMF responsible for the previously observed reduction in IL-1 activity, the current experiment examined not only the effect of exposure to electric and magnetic fields, but also the magnetic field component alone. In the current study, IL-2 was examined to characterize the effects of EMF exposure on an indicator of T cell responses. 45 Suffolk ewe lambs were randomized into three groups of 15 animals each. One group of animals was placed in the EMF pen, located directly beneath the transmission line. A second group was placed in the shielded MF (magnetic field only) pen, also directly beneath the transmission line. The third group of animals was placed in the control pen located several hundred meters away from the transmission line. During the 27 month exposure period, blood samples were taken from all animals monthly. When the data were analyzed collectively over time, no significant differences between the groups were found for IL-1 or IL-2 activity. In previous studies ewe lambs of 8-10 weeks of age were used as the study animals and significant differences in IL-1 activity were observed after exposure of these animals to EMF at mean magnetic fields of 3.5-3.8 microT (35-38 mG) and mean electric fields of 5.2-5.8 kV/m. At the start of the current study EMF levels were reduced as compared to previous studies. One interpretation of the current data is that magnetic field strength and age of the animals may be important variables in determining whether EMF exposure will affect IL-1 activity.     

Survey of electromagnetic field exposure in bedrooms of residences in lower Austria

Previous investigations of exposure to electric, magnetic, or electromagnetic fields (EMF) in households were either about electricity supply EMFs or radio frequency EMFs (RF‐EMFs). We report results from spot measurements at the bedside that comprise electrostatic fields, extremely low‐frequency electric fields (ELF‐EFs), extremely low‐frequency magnetic fields (ELF‐MFs), and RF‐EMFs. Measurements were taken in 226 households throughout Lower Austria. In addition, effects of simple reduction measures (e.g., removal of clock radios or increasing their distance from the bed, turning off Digital Enhanced Cordless Telecommunication (DECT) telephone base stations) were assessed. All measurements were well below International Commission on Non‐Ionizing Radiation Protection (ICNIRP) guideline levels. Average night‐time ELF‐MFs (long‐term measurement from 10 pm to 6 am, geometric mean over households) above 100 nT were obtained in 2.3%, and RF‐EMFs above 1000 µW/m² in 7.1% of households. Highest ELF‐EFs were primarily due to lamps beside the bed (max = 166 V/m), and highest ELF‐MFs because of transformers of devices (max = 1030 nT) or high current of power lines (max = 380 nT). The highest values of RF‐EMFs were caused by DECT telephone base stations (max = 28979 µW/m²) and mobile phone base stations (max = 4872 µW/m²). Simple reduction measures resulted in an average decrease of 23 nT for ELF‐MFs, 23 V/m for ELF‐EFs, and 246 µW/m² for RF‐EMFs. A small but statistically significant correlation between ELF‐MF exposure and overall RF‐EMF levels of R = 0.16 (P = 0.008) was computed that was independent of type (flat, single family) and location (urban, rural) of houses. Bioelectromagnetics 31:200–208, 2010. © 2009 Wiley‐Liss, Inc.     

The effect of pulsed electromagnetic fields on the physiologic behaviour of a human astrocytoma cell line

We evaluated the effects of 50 Hz pulsed electromagnetic fields (EMFs) with a peak magnetic field of 3 mT on human astrocytoma cells. Our results clearly demonstrate that, after the cells were exposed to EMFs for 24 h, the basal [Ca(2+)](i) levels increased significantly from 124+/-51 nM to 200+/-79 nM. Pretreatment of the cells with 1.2 microM substance P increased the [Ca(2+)](i) to 555+/-278 nM, while EMF exposure caused a significant drop in [Ca(2+)](i) to 327+/-146 nM. The overall effect of EMFs probably depends on the prevailing Ca(2+) conditions of the cells. After exposure, the proliferative responses of both normal and substance P-pretreated cells increased slightly from 1.03 to 1.07 and 1.04 to 1.06, respectively. U-373 MG cells spontaneously released about 10 pg/ml of interleukin-6 which was significantly increased after the addition of substance P. Moreover, immediately after EMF exposure and 24 h thereafter, the interleukin-6 levels were more elevated (about 40%) than in controls. On the whole, our data suggest that, by changing the properties of cell membranes, EMFs can influence Ca(2+) transport processes and hence Ca(2+) homeostasis. The increased levels of interleukin-6 after 24 h of EMF exposure may confirm the complex connection between Ca(2+) levels, substance P and the cytokine network.     

Ets1 oncogene induction by ELF-modulated 50 MHz radiofrequency electromagnetic field

We have analyzed gene expression in hemopoietic and testicular cell types after their exposure to 50 MHz radiofrequency (RF) non-ionizing radiation modulated (80%) with a 16 Hz frequency. The exposure system generates a 0.2 microT magnetic field parallel to the ground and a 60 V/m electric field orthogonal to the earth's magnetic field. Exposure conditions were selected so as to interfere with the calcium ion flow. Under these electromagnetic field (EMF) conditions, we observed an overexpression of the ets1 mRNA in Jurkat T-lymphoblastoid and Leydig TM3 cell lines. This effect was observed only in the presence of the 16 Hz modulation, corresponding to the resonance frequency for calcium ion with a DC magnetic field of 45.7 microT. We have also identified a putative candidate gene repressed after EMF exposure. The experimental model described in this paper may contribute to the understanding of the biological mechanisms involved in EMF effects.     

Effects of low-level combined static and weak low-frequency alternating magnetic fields on cytokine production and tumor development in mice

We investigated the effects of weak combined magnetic fields (MFs) produced by superimposing a constant MF (in the range 30 - 150 µT) and an alternating MF (100 or 200 nT) on cytokine production in healthy Balb/C male mice exposed 2 h daily for 14 days. The alternating magnetic field was a sum of several frequencies (ranging from 2.5 - 17.5 Hz). The frequencies of the alternating magnetic field were calculated formally based on the cyclotron resonance of ions of free amino acids (glutamic and aspartic acids, arginine, lysine, histidine, and tyrosine). The selection of different intensity and frequency combinations of constant and alternating magnetic fields was performed to find the optimal characteristics for cytokine production stimulation in immune cells. MF with a constant component of 60 μT and an alternating component of 100 nT, which was a sum of six frequencies (from 5 to 7 Hz), was found to stimulate the production of tumor necrosis factor-α, interferon-gamma, interleukin-2, and interleukin-3 in healthy mouse cells and induce cytokine accumulation in blood plasma. Then, we studied the effect of this MF on tumor-bearing mice with solid tumors induced by Ehrlich ascite carcinoma cells by observing tumor development processes, including tumor size, mouse survival rate, and average lifespan. Tumor-bearing mice exposed to a combined constant magnetic field of 60 μT and an alternating magnetic field of 100 nT containing six frequencies showed a strong suppression of tumor growth with an increase in survival rate and enhancement of average lifespan.     

Effect of weak and superweak magnetic fields on intensity and asexual reproduction of the planarian Dugesia tigrina

It was shown that the exposure to combined weak and extraweak magnetic fields (permanent component 42 microT; variable component of an amplitude of 100 nT, frequency 1-60 Hz) increases the intensity of asexual propagation of planarians Dugesia tigrina. The effect of combined magnetic fields is most pronounced at frequencies of 1, 3.7, and 32 Hz. The presence of concomitant technogeneous fields (50 Hz, 30 nT) does not markedly influence the effects of weak magnetic fields with a small variable component. Upon realization of effects of weak magnetic fields, their both components are of great importance; the absence of one (permanent) component changes the sing of the effect to the opposite. The transfer of the effect to planarians through water pretreated with magnetic fields probably indicates that aqueous medium is involved in the realization of biological effects of weak magnetic fields.     

Project NEMESIS: perception of a 50 Hz electric and magnetic field at low intensities (laboratory experiment).

The Electrical Hypersensitivity Syndrome (EHS) is a condition where people suffer from various nonspecific health symptoms attributed to an assumed adverse effect of electric and magnetic fields (EMF). Many EHS patients report the ability to consciously perceive EMF at very low intensities. The existence of a direct EMF perception could be the key to explain at least partially the aetiology of EHS through stress mechanisms and allow the comparison with well known environmental stressors such as noise or odor. The double blind laboratory experiment tested the hypothesis that there are subjects with the ability to perceive 50 Hz EMF at 100 V/m and 6 microT (EMF sensitive) and to investigate the prevalence of EMF sensitivity in a group consisting of subjects with or without self-reported EHS. A total of 63 volunteers, 49 with EHS and 14 controls, took part in the EMF perception experiment, where 10 sham and 10 exposed 2 min blocks had to be judged in randomized sequence (field on/field off). Seven out of 63 subjects reached a statistically significant result which points to the existence of a small EMF sensitive subgroup within the study group. There was no relevant difference between the subjects with self reported EHS and those without in terms of the success rate in the field perception experiment, as well as the number and types of symptoms encountered during the test. The results of the EMF perception experiment suggest that EHS is not a prerequisite for the ability to consciously perceive weak EMF and vice versa.     

Preliminary background indoor EMF measurements in Greece

The main purpose of this work was to investigate the fluctuation of Greek indoor electromagnetic field (EMF) intensity values and identify peaks that might occur. The scientific interest is mainly focused on the bands of extremely low-frequency (ELF) magnetic fields and radiofrequency (RF) electric fields which have been suggested to be possibly carcinogenic to humans by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR).Electromagnetic radiation (EMR) measurements were performed in a variety of indoor dwellings, in Attica and in the islands of Zakynthos and Lesvos.A total number of 4540 measurements were taken in a wide frequency range (50 Hz–2100 MHz) of which 3301 in Attica, 963 in Lesvos and 276 in Zakynthos.Statistical analysis of the data revealed specific statistically significant differences between the mean values of the electric (ELF and RF) but not the magnetic (ELF) field strengths measured at different distances from the EMF source, as well as between some of the mean values of the RF electric field at different bands. Some statistically significant differences between mean electric field values at different geographic locations were also identified.As far as the RF electric field is concerned, the maximum values, in most cases, were below 0.5 V/m, however increased values above 1 V/m and up to 5.6 V/m were occasionally observed. The ELF magnetic field values were lower than 1 μT. It may be concluded that overall, the observed indoor EMF intensity values remained well below domestic and European established limits.     

Inflammation-driven reprogramming of CD4+ Foxp3+ regulatory T cells into pathogenic Th1/Th17 T effectors is abrogated by mTOR inhibition in vivo

While natural CD4(+)Foxp3(+) regulatory T (nT(REG)) cells have long been viewed as a stable and distinct lineage that is committed to suppressive functions in vivo, recent evidence supporting this notion remains highly controversial. We sought to determine whether Foxp3 expression and the nT(REG) cell phenotype are stable in vivo and modulated by the inflammatory microenvironment. Here, we show that Foxp3(+) nT(REG) cells from thymic or peripheral lymphoid organs reveal extensive functional plasticity in vivo. We show that nT(REG) cells readily lose Foxp3 expression, destabilizing their phenotype, in turn, enabling them to reprogram into Th1 and Th17 effector cells. nT(REG) cell reprogramming is a characteristic of the entire Foxp3(+) nT(REG) population and the stable Foxp3(NEG) T(REG) cell phenotype is associated with a methylated foxp3 promoter. The extent of nT(REG) cell reprogramming is modulated by the presence of effector T cell-mediated signals, and occurs independently of variation in IL-2 production in vivo. Moreover, the gut microenvironment or parasitic infection favours the reprogramming of Foxp3(+) T(REG) cells into effector T cells and promotes host immunity. IL-17 is predominantly produced by reprogrammed Foxp3(+) nT(REG) cells, and precedes Foxp3 down-regulation, a process accentuated in mesenteric sites. Lastly, mTOR inhibition with the immunosuppressive drug, rapamycin, stabilizes Foxp3 expression in T(REG) cells and strongly inhibits IL-17 but not RORγt expression in reprogrammed Foxp3(-) T(REG) cells. Overall, inflammatory signals modulate mTOR signalling and influence the stability of the Foxp3(+) nT(REG) cell phenotype.     

Effects of electromagnetic field on the batch cultivation and nutritional composition of Spirulina platensis in an air-lift photobioreactor

Spirulina platensis was batch cultivated in a novel 3.5l magnetic air-lift photobioreactor with external-loop on which 0-0.55 T electromagnetic field (EMF) was imposed to investigate the EMF effects on the algal growth and nutrition composition. At the same time, the correlative mechanism was discussed mainly based on C, N, P uptake. It was found that, EMF has double-side effects on S. platensis cultivation depend on EMF intensity. 0.25 T EMF stress was found to be suitable for the algal cultivation enhancement increasing the maximum cell dry weight by 22% in a time period two days less than that of the control at 35 degrees C and 252 micromol photonsm(-2)S(-1). In addition, the nutritional composition of S. platensis was improved in both essential amino acids such as histidine and trace elements Ni, Sr, Cu, Mg, Fe, Mn, Ca, Co and V. It was suggested it was possible to optimize the cultivation process of S. platensis by imposing suitable weak EMF which may enhance the nutrition assimilation e.g. C, N, P and minerals by S. platensis.     

The effect of combined magnetic fields, adjusted to ion-cyclotron resonance for Ca ions, on intensity of division in planaria

The combination of a constant (42 mkT1) and parallel to it a changing magnetic field on a frequency of 32 Hz (it corresponds to cyclotron frequency for Ca2+ ions) is shown to have a changing magnetic field amplitude-dependent effect on intensity of division in planaria. A stimulating effect has been observed at the magnitude of a changing component equal to 100 nT, but the amount of division significantly decreased at 250 nT and no impact of the magnetic field was registered at 500 nT1.     

IL-12 inhibits thymic involution by enhancing IL-7- and IL-2-induced thymocyte proliferation

IL-12 has been reported to affect thymic T cell selection, but the role of IL-12 in thymic involution has not been studied. We found that in vivo, IL-12b knockout (IL-12b(-/-)) mice exhibited accelerated thymic involution compared with wild-type (WT) B6 mice. This is characterized by an increase in thymocytes with the early development stage phenotype of CD25(-)CD44(+)CD4(-)CD8(-) in aged IL-12b(-/-) mice. Histologically, there were accelerated degeneration of thymic extracellular matrix and blood vessels, a significantly decreased thymic cortex/medulla ratio, and increased apoptotic cells in aged IL-12b(-/-) mice compared with WT mice. There was, however, no apparent defect in thymic structure and thymocyte development in young IL-12(-/-) mice. These results suggest the importance of IL-12 in maintaining thymic integrity and function during the aging process. Surprisingly, in WT B6 mice, there was no age-related decrease in the levels of IL-12 produced from thymic dendritic cells. Stimulation of thymocytes with IL-12 alone also did not enhance the thymocyte proliferative response in vitro. IL-12, however, provided a strong synergistic effect to augment the IL-7 or IL-2 induced thymocyte proliferative response, especially in aged WT and IL-12b(-/-) mice. Our data strongly support the role of IL-12 as an enhancement cytokine, which acts through its interactions with other cytokines to maintain thymic T cell function and development during aging.     

The effect of a peat-based preparation on mitogen-induced proliferation of thymocytes in non-treated and hydrocortisone-suppressed mice.

The studies were carried out on Balb/c mice (5-6 weeks of age) treated with a peat-based preparation (PBP), administered i.p. once or four times at 24 h intervals at doses of 0.01; 0.1 or 1 mg/kg. Additionally, hydrocortisone was injected i.p. to selected mice at a single dose of 125 mg/kg. The results show that PBP temporarily enhances the proliferative capability of murine thymocytes stimulated in vitro with concanavalin A (Con A) and phytohemagglutinin (PHA). The effect of PBP depends on the number of subsequent doses, but does not depend on the dose applied. A single PBP administration does not affect the proliferative response of thymocytes to Con A and PHA. A single injection of PBP (doses from 0.01 to 1 mg/kg) does not change the number of thymic cells and weight ratio of this organ. Increased doses of subsequent PBP injections (0.01 and 0.1 mg/kg) do not affect the number of thymocytes, but temporarily increase the weight ratio of the thymus two days after the last injection. Administration of PBP prior to hydrocortisone prevents the suppressive effect of the drug on proliferative response of thymocytes stimulated in vitro with Con A and PHA, at the same time increasing the proliferative response of thymic cells to the two mitogens in relation to the control group (hydrocortisone-free). The effect of a single dose of PBP depends on the dose applied--the weakest preventive effect was observed at a dose of 0.01 mg/kg. An increase in the number of subsequent PBP doses, irrespective of a dose applied, prolongs the protective action of the drug on proliferative activity of thymocytes stimulated in vitro with these mitogenes. Moreover, the results obtained in the studies show that PBP partially prevents the suppressive effect of hydrocortisone, as the number of thymic cells and weight ratio of this organ drastically decreased. PBP accelerates regeneration of the thymus, but this depends on a dose applied and the number of subsequent doses. The result was the strongest and the fastest when PBP was injected four times at a dose of 1 mg/kg. It seems quite likely that the thymic regeneration due to PBP is connected with the effect of this drug on maturation and differentiation of thymic cells.     

Thymic epithelial cells responsible for impaired generation of NK-T thymocytes in Alymphoplasia mutant mice

We have previously shown that the generation of an NK1.1+TCRalphabeta+ (NK-T) cell population is severely impaired in an alymphoplasia mutant (aly/aly) mouse strain and the defect resides in the thymic environment. In the present study, to elucidate the thymic stromal component(s) that affects the development of NK-T cells, radiation bone marrow chimeras were established with the aly/aly mouse as a donor and either the beta2 microglobulin knockout (beta2m-/-) or the CD1d1-/- mouse that also lacks the NK-T cell population as a recipient. A normal population of NK-T cells with a typical NK-T phenotype and functions was detected in both the thymus and the spleen of these chimeras. These findings indicated that a radiation-resistant CD1(-) component of the thymus supported generation of functional NK-T cells from aly/aly precursors. Furthermore, transfer of an intact medullary thymic epithelial cell line into aly/aly thymus significantly induced the generation of NK-T cells in the thymus. These findings suggest that CD1 molecules of bone marrow-derived cells and the medullary epithelial cells acted in concert in the generation of the NK-T cell population and that a function(s) of the medullary thymic epithelial cells other than direct presentation of CD1 molecules to the NK-T precursors is indispensable for the development of NK-T cells.     

Alterations of thymic morphology and antioxidant biomarkers in 60-day-old male rats following exposure to a continuous 900 MHz electromagnetic field during adolescence

We investigated changes in thymic tissue of male rats exposed to a 900 megahertz (MHz) electromagnetic field (EMF) on postnatal days 22–59. Three groups of six 21-day-old male Sprague-Dawley rats were allocated as: control (CG), sham (SG) and EMF (EMFG) groups. No procedure was performed on the CG rats. SG rats were placed in a Plexiglas cage for 1 h every day between postnatal days 22 and 59 without exposure to EMF. EMFG rats were placed in the same cage for the same periods as the SG rats and were exposed to 900 MHz EMF. Rats were sacrificed on postnatal day 60. Sections of thymus were stained for histological assessment. Oxidant/antioxidant parameters were investigated biochemically. Malondialdehyde (MDA) levels in EMFG increased compared to the other groups. Extravascular erythrocytes were observed in the medullary/corticomedullary regions in EMFG sections. We found that 900 MHz EMF applied for 1 h/day on postnatal days 22–59 can increase tissue MDA and histopathological changes in male rat thymic tissue.     

Differences in the pattern of proliferative response with age in thymocytes undergoing spontaneous and induced proliferation

The proliferative capacity of thymocytes from C3H/HeJ mice decrease as the animals attain maturity. The proliferative response of thymocytes from 24- to 28-week-old mice to stimulation with concanavalin A (Con A) is only 20% of that observed at 4 weeks of age. The decreased proliferative capacity of thymocytes in response to Con A stimulation observed between 4 and 24 weeks of age closely correlates to the drop in thymic weight and cellularity observed during this period. In contrast, the spontaneous proliferative capacity of thymocytes, as well as proliferation of thymocytes in response to stimulation with phorbol myristate acetate (PMA) and ionomycin, drops only slightly during this period, as proliferation under these condition in thymocytes from 24- to 28-week-old mice is approximately 65-70% of that observed in 4-week-old animals. We have previously shown that cytoplasmic extracts from proliferating lymphoid cells contain a factor, termed the activator of DNA replication (ADR), which is capable of inducing DNA synthesis in isolated, quiescent nuclei. We show in this study that the decreased proliferative capacity of thymocytes during whole organism maturation and thymic involution is associated with decreased endogenous levels of ADR, while nuclear sensitivity of thymocyte to ADR was retained during these process. The diminution of ADR activity during thymic involution was quantitatively greater than the loss in proliferative capacity.     

Suppression of natural killer cell activity on Candida stellatoidea by a 50 Hz magnetic field

Exposure to electromagnetic fields (EMF) is ubiquitous for almost all individuals living in industrialized countries. Epidemiological and laboratory studies suggest that exposure to Extremely Low Frequency (ELF) EMF increase cancer risk. The immune system functions as one of the body's main protective mechanisms, and Natural Killer (NK) cells are a subset of lymphocytes that can destroy several types of tumor cells. In this study, we investigated, NK cell activity after exposure to a 50 Hertz (Hz), 2 mT magnetic field generated by a Helmholtz Coil. Nineteen male, 10-12 week old guinea pigs were used, and NK cytotoxic activity of splenocytes was measured in vitro by natural anticandidial colorimetric index. The Mann-Whitney U test was applied for statistical analysis. NK cell cytotoxic activity was decreased in exposed compared to controls. Our data suggests that part of the immune system, the NK cell, can be suppressed by a 50 Hz magnetic field.     

In vitro increase of the fluid-phase endocytosis induced by pulsed radiofrequency electromagnetic fields: importance of the electric field component

Nowadays, due to the wide use of mobile phones, the possible biological effects of electromagnetic fields (EMF) become a public health general concern. Despite intensive research, there are no widely accepted theories about the interactions between EMFs and living cells, and the experimental data are often controversial. We examined the effects of mobile phones EMF (envelope frequency of 217 Hz, carrier frequency of 900 MHz and pulse duration of 580 micros) or its pure, low-frequency pulsed electric field component on fluid-phase endocytosis. In both cases, with exposures exceeding 10 min, an increase of the fluid-phase endocytosis rate was observed ( approximately 1.5-fold), on three different cell types. This increase is an all-or-nothing type of response that is occurring for threshold values comprised between 1.3 and 2.6 W/kg for the delivered EMF powers and between 1.1 and 1.5 V/cm for the electric fields intensities depending upon the cell type. The electric component of these EMFs is shown to be responsible for the observed increase. Variations of frequency or pulse duration of the electric pulses are shown to be without effect. Thus, EMF, via their electrical component, can perturb one of the most fundamental physiological functions of the cells-endocytosis.