Combined millimeter wave and cyclophosphamide therapy of an experimental murine melanoma

The objective of the present studies was to investigate whether millimeter wave (MMW) therapy can increase the efficacy of cyclophosphamide (CPA), a commonly used anti-cancer drug. The effect of combined MMW-CPA treatment on melanoma growth was compared to CPA treatment alone in a murine model. MMWs were produced with a Russian made YAV-1 generator. The device produced 42.2 +/- 0.2 GHz modulated wave radiation through a 10 x 20 mm rectangular output horn. The animals, SKH-1 hairless female mice, were irradiated on the nasal area. Peak SAR and incident power density were measured as 730 +/- 100 W/kg and 36.5 +/- 5 mW/cm2, respectively. The maximum skin surface temperature elevation measured at the end of 30 min irradiation was 1.5 degrees C. B16F10 melanoma cells (0.2 x 10(6)) were implanted subcutaneously into the left flank of mice on day 1 of the experiment. On days 4-8, CPA was administered intraperitoneally (30 mg/kg/day). MMW irradiation was applied concurrently with, prior to or following CPA administration. A significant reduction (P < .05) in tumor growth was observed with CPA treatment, but MMW irradiation did not provide additional therapeutic benefit as compared to CPA alone. Similar results were obtained when MMW irradiation was applied both prior to and following CPA treatment.     

Millimeter wave effects on electrical responses of the sural nerve in vivo

Millimeter wave (MMW, 42.25 GHz)‐induced changes in electrical activity of the murine sural nerve were studied in vivo using external electrode recordings. MMW were applied to the receptive field of the sural nerve in the hind paw. We found two types of responses of the sural nerve to MMW exposure. First, MMW exposure at the incident power density ≥45 mW/cm² inhibited the spontaneous electrical activity. Exposure with lower intensities (10–30 mW/cm²) produced no detectable changes in the firing rate. Second, the nerve responded to the cessation of MMW exposure with a transient increase in the firing rate. The effect lasted 20–40 s. The threshold intensity for this effect was 160 mW/cm². Radiant heat exposure reproduced only the inhibitory effect of MMW but not the transient excitatory response. Depletion of mast cells by compound 48/80 eliminated the transient response of the nerve. It was suggested that the cold sensitive fibers were responsible for the inhibitory effect of MMW and radiant heat exposures. However, the receptors and mechanisms involved in inducing the transient response to MMW exposure are not clear. The hypothesis of mast cell involvement was discussed. Bioelectromagnetics 31:180–190, 2010. © 2009 Wiley‐Liss, Inc.     

Cell-to-cell communication in response of E. coli cells at different phases of growth to low-intensity microwaves

Effects of millimeter waves (MMW) at the frequency of 51.755 GHz were studied in logarithmic and stationary E. coli cells at various cell densities. The changes in the genome conformational state (GCS) were analyzed by the method of anomalous viscosity time dependence (AVTD). Before lysis, the cells were adjusted to the cell density of 4x10(7) cells/ml and all AVTD measurements were run at this cell density. Stationary cells responded to MMW by increase in AVTD, while the same MMW exposure decreased AVTD in logarithmic cells. MMW effects depended on cell density during exposure and were stronger for stationary cells. The observed dependence on cell density suggested a cell-to-cell communication between cells during exposure to microwaves. Decrease in power density (PD) resulted in more striking differences between responses at different cell densities. The data provided evidence that intercellular communication in response to MMW depended on cell status and PD of microwaves. The MMW effects were studied in more detail at low intensity of 10(-17) W/cm(2) in the range of cell densities 4x10(7) to 8x10(8) cells/ml. The obtained sigmoid-like dependence of MMW effect on cell density saturated at approximately 5x10(8) cells/ml. The dependence of MMW effect on cell density was very similar in this study and in previous studies with weak extremely low frequency (ELF) electromagnetic fields (EMF). The data suggested that cell-to-cell communication might be involved in response of cells to weak EMF of various frequency ranges.     

Millimeter wave-induced suppression of B16 F10 melanoma growth in mice: involvement of endogenous opioids

Millimeter wave treatment (MMWT) is widely used in Eastern European countries, but is virtually unknown in Western medicine. Among reported MMWT effects is suppression of tumor growth. The main aim of the present "blind" and dosimetrically controlled experiments was to evaluate quantitatively the ability of MMWT to influence tumor growth and to assess whether endogenous opioids are involved. The murine experimental model of B16 F10 melanoma subcutaneous growth was used. MMWT characteristics were: frequency, 61.22 GHz; average incident power density, 13.3 x 10(-3) W/cm2; single exposure duration, 15 min; and exposure area, nose. Naloxone (1 mg/kg, intraperitoneally, 30 min prior to MMWT) was used as a nonspecific blocker of opioid receptors. Five daily MMW exposures, if applied starting at the fifth day following B16 melanoma cell injection, suppressed subcutaneous tumor growth. Pretreatment with naloxone completely abolished the MMWT-induced suppression of melanoma growth. The same course of 5 MMW treatments, if started on day 1 or day 10 following tumor inoculations, was ineffective. We concluded that MMWT has an anticancer therapeutic potential and that endogenous opioids are involved in MMWT-induced suppression of melanoma growth in mice. However, appropriate indications and contraindications have to be developed experimentally before recommending MMWT for clinical usage.     

Cooperative Response of Escherichia Coli Cells to the Resonance Effect of Millimeter Waves at Super Low Intensity

Cells of Escherichia coli K12 AB1157 were irradiated with millimeter waves (MMW) within the power density (PD) range of 10^?20 to 10 ⁴ W/cm². MMW were applied for 0.5–70 min at 51.76 GHz or 41.32 GHz at which, as had been shown earlier, MMW resonantly changes the genome conformational state (GCS) of E. coli K12 AB1157 cells. The changes in the GCS were tested with the method of anomalous viscosity time dependence (AVTD). It was demonstrated that the resonance effect of MMW manifests itself at PD up to 10^?19 W/cm². Dependences of MMW effect on power density and time of exposure proved to have distinct characteristics when cells are irradiated during the logarithmic or stationary phases of the culture's growth. It was found that the resonance effect of MMW on the GCS of E. coli cells at the early stationary phase changes the developmental dynamics of the irradiated culture. It was established for the first time that the magnitude of the resonance MMW effect depends on the concentration of irradiated cells. An analysis of the results indicates an electromagnetic rather than diffusion nature of the cells' cooperative responses to millimeter waves.     

Effect of cyclophosphamide and 61.22 GHz millimeter waves on T-cell, B-cell, and macrophage functions

The present study was undertaken to investigate whether millimeter waves (MMWs) at 61.22 GHz can modulate the effect of cyclophosphamide (CPA), an anti-cancer drug, on the immune functions of mice. During the exposure each mouse's nose was placed in front of the center of the antenna aperture (1.5 x 1.5 cm) of MMW generator. The device produced 61.22 +/- 0.2 GHz wave radiation. Spatial peak Specific Absorption Rate (SAR) at the skin surface and spatial peak incident power density were measured as 885 +/- 100 W/kg and 31 +/- 5 mW/cm(2), respectively. Duration of the exposure was 30 min each day for 3 consecutive days. The maximum temperature elevation at the tip of the nose, measured at the end of 30 min, was 1 degrees C. CPA injection (100 mg/kg) was given intraperitoneally on the second day of exposure to MMWs. The animals were sacrificed 2, 5, and 7 days after CPA administration. MMW exposure caused upregulation in tumor necrosis factor-alpha (TNF-alpha) production in peritoneal macrophages suppressed by CPA administration. MMWs also caused a significant increase in interferon-gamma (IFN-gamma) production by splenocytes and enhanced proliferative activity of T-cells. Conversely, no changes were observed in interleukin-10 (IL-10) level and B-cell proliferation. These results suggest that MMWs accelerate the recovery process selectively through a T-cell-mediated immune response.     

Electromagnetic millimeter wave induced hypoalgesia: frequency dependence and involvement of endogenous opioids

Millimeter wave treatment (MMWT) is based on the systemic biological effects that develop following local skin exposure to low power electromagnetic waves in the millimeter range. In the present set of experiments, the hypoalgesic effect of this treatment was analyzed in mice. The murine nose area was exposed to MMW of "therapeutic" frequencies: 42.25, 53.57, and 61.22 GHz. MMWT-induced hypoalgesia was shown to be frequency dependent in two experimental models: (1) the cold water tail-flick test (chronic non-neuropathic pain), and (2) the wire surface test (chronic neuropathic pain following unilateral constriction injury to the sciatic nerve). Maximum hypoalgesic effect was obtained when the frequency was 61.22 GHz. Other exposure parameters were: incident power density = 13.3 mW/cm(2), duration of each exposure = 15 min. Involvement of delta and kappa endogenous opioids in the MMWT-induced hypoalgesia was demonstrated using selective blockers of delta- and kappa-opioid receptors and the direct ELISA measurement of endogenous opioids in CNS tissue. Possible mechanisms of the effect and the perspectives of the clinical application of MMWT are discussed.     

Numerical modeling and dosimetry of the 35 mm Petri dish under 46 GHz millimeter wave exposure

Experimental studies on effects of millimeter wave (MMW) exposure on cells cultured in Petri dishes have attracted interest in recent decades. To improve the quantification of the biological responses toward the MMW energy, an accurate and precise MMW dosimetry is to be provided. By using the finite difference time domain (FDTD) method, the numerical dosimetry is performed for a typical 35 mm Petri dish under 46 GHz continuous MMW exposure from an irradiator of a specified power pattern. With the aim of building a precise model, the meniscus at the interface between the culture solution and the Petri dish sidewall is taken into account, followed by the modeling of smooth edges of the Petri dish. The trilinear interpolation is introduced to assist the FDTD method to obtain a more precise dosimetric assessment. The specific absorption rate (SAR) distributions in the cornea cells covered by culture solution in the Petri dish are calculated and compared to display the effects of using Petri dish models of various precision and the trilinear interpolation on dosimetry results. In addition, the SAR distribution in the cells is analyzed to study its homogeneity. The results indicate that the precise Petri dish model and the application of the trilinear interpolation are helpful in improving the precision of numerical dosimetry. It is also revealed that the inhomogeneity of the SAR distribution is well beyond neglect, which deserves cautious consideration in experiments investigating MMW effects on cells in vitro.     

Millimeter wave induced reversible externalization of phosphatidylserine molecules in cells exposed in vitro

In vitro exposure of refrigerated samples (4 degrees C) of anti-coagulated blood with millimeter waves (MMWs) at incident power densities (IPDs) between 0.55 and 1.23 W/cm2 has been found to induce clot formation. We found a small but statistically significant change in clot size with increasing IPD value. MMW exposure of blood samples starting at room temperature (22 degrees C) did not induce blood coagulation; neither did conventional heating at temperatures up to 40 degrees C. Since cell-free plasma did not clot upon MMW exposure, the role of blood cells was particularly analyzed. Experiments on various mixtures of blood cells with plasma revealed an important role of red blood cells (RBC) in the coagulation process. Plasma coagulation also developed within the MMW beam above dense keratinocyte (HaCaT) monolayers suggesting it lacked cell-type specificity. We hypothesized that alteration of the membrane surface in exposed cells might be responsible for the circumscribed coagulation. The thrombogenic role of externalized phosphatidylserine (PS) molecules is well known. Therefore, we carried out experiments for immunolabeling PS molecules with fluorescein isothiocyanate (FITC)-conjugated Annexin V on exposed cells. Fluorescence microscopy of the adherent human keratinocytes (HaCaT) and murine melanoma cells (B16F10) showed that MMW exposure at an IPD of 1.23 W/cm2 is capable of inducing reversible externalization of PS molecules in cells within the beam area without detectable membrane damage. Nonadherent Jurkat cells exposed to MMW at an IPD of 34.5 mW/cm2 also showed reversible PS externalization with flow cytometry, whether the cell temperature was held constant or permitted to rise. These results suggest that certain biological effects induced by MMWs could be initiated by membrane changes in exposed cells.     

Effect of millimeter waves on natural killer cell activation

Millimeter wave therapy (MMWT) is being widely used for the treatment of many diseases in Russia and other East European countries. MMWT has been reported to reduce the toxic effects of chemotherapy on the immune system. The present study was undertaken to investigate whether millimeter waves (MMWs) can modulate the effect of cyclophosphamide (CPA), an anticancer drug, on natural killer (NK) cell activity. NK cells play an important role in the antitumor response. MMWs were produced with a Russian-made YAV-1 generator. The device produced modulated 42.2 +/- 0.2 GHz radiation through a 10 x 20 mm rectangular output horn. Mice, restrained in plastic tubes, were irradiated on the nasal area. Peak SAR at the skin surface and peak incident power density were measured as 622 +/- 100 W/kg and 31 +/- 5 mW/cm2, respectively. The maximum temperature elevation, measured at the end of 30 min, was 1 degrees C. The animals, restrained in plastic tubes, were irradiated on the nasal area. CPA injection (100 mg/kg) was given intraperitoneally on the second day of 3-days exposure to MMWs. All the irradiation procedures were performed in a blinded manner. NK cell activation and cytotoxicity were measured after 2, 5, and 7 days following CPA injection. Flow cytometry of NK cells showed that CPA treatment caused a marked enhancement in NK cell activation. The level of CD69 expression, which represents a functional triggering molecule on activated NK cells, was increased in the CPA group at all the time points tested as compared to untreated mice. However, the most enhancement in CD69 expression was observed on day 7. A significant increase in TNF-alpha level was also observed on day 7 following CPA administration. On the other hand, CPA caused a suppression of the cytolytic activity of NK cells. MMW irradiation of the CPA treated groups resulted in further enhancement of CD69 expression on NK cells, as well as in production of TNF-alpha. Furthermore, MMW irradiation restored CPA induced suppression of the cytolytic activity of NK cells. Our results show that MMW irradiation at 42.2 GHz can up-regulate NK cell functions.     

Laser power dependence of mechanoluminescence in metals

Mechanoluminescence (ML) glow is produced on the back side when the front of a metal sample is irradiated with infrared Nd:YAG laser pulses. An incident laser beam with a power density below the plasma‐flare onset threshold causes a rise in temperature in the studied metal. As the incident laser power density increases, the intensity of the ML glow signal also increases. On the basis of the laser power density‐induced temperature, an expression is derived for the temperature‐induced thermal stress. An expression is derived for the correlation between thermal stress and laser power density, which indicates that the temperature‐induced thermal stress is directly related to the incident laser power density. In the region of plastic deformation, temperature‐induced thermal stress is related to the strain and, consequently, to the emitted ML intensity. Finally, an expression is derived for the laser power dependence of the ML intensity, and good agreement is found between the theoretical and experimental results. Copyright © 2016 John Wiley & Sons, Ltd.     

Thermal Mechanisms of Millimeter Wave Stimulation of Excitable Cells

Interactions between millimeter waves (MMWs) and biological systems have received increasing attention due to the growing use of MMW radiation in technologies ranging from experimental medical devices to telecommunications and airport security. Studies have shown that MMW exposure alters cellular function, especially in neurons and muscles. However, the biophysical mechanisms underlying such effects are still poorly understood. Due to the high aqueous absorbance of MMW, thermal mechanisms are likely. However, nonthermal mechanisms based on resonance effects have also been postulated. We studied MMW stimulation in a simplified preparation comprising Xenopus laevis oocytes expressing proteins that underlie membrane excitability. Using electrophysiological recordings simultaneously with 60 GHz stimulation, we observed changes in the kinetics and activity levels of voltage-gated potassium and sodium channels and a sodium-potassium pump that are consistent with a thermal mechanism. Furthermore, we showed that MMW stimulation significantly increased the action potential firing rate in oocytes coexpressing voltage-gated sodium and potassium channels, as predicted by thermal terms in the Hodgkin-Huxley model of neurons. Our results suggest that MMW stimulation produces significant thermally mediated effects on excitable cells via basic thermodynamic mechanisms that must be taken into account in the study and use of MMW radiation in biological systems.     

Thermal Mechanisms of Millimeter Wave Stimulation of Excitable Cells

Interactions between millimeter waves (MMWs) and biological systems have received increasing attention due to the growing use of MMW radiation in technologies ranging from experimental medical devices to telecommunications and airport security. Studies have shown that MMW exposure alters cellular function, especially in neurons and muscles. However, the biophysical mechanisms underlying such effects are still poorly understood. Due to the high aqueous absorbance of MMW, thermal mechanisms are likely. However, nonthermal mechanisms based on resonance effects have also been postulated. We studied MMW stimulation in a simplified preparation comprising Xenopus laevis oocytes expressing proteins that underlie membrane excitability. Using electrophysiological recordings simultaneously with 60 GHz stimulation, we observed changes in the kinetics and activity levels of voltage-gated potassium and sodium channels and a sodium-potassium pump that are consistent with a thermal mechanism. Furthermore, we showed that MMW stimulation significantly increased the action potential firing rate in oocytes coexpressing voltage-gated sodium and potassium channels, as predicted by thermal terms in the Hodgkin-Huxley model of neurons. Our results suggest that MMW stimulation produces significant thermally mediated effects on excitable cells via basic thermodynamic mechanisms that must be taken into account in the study and use of MMW radiation in biological systems.     

Resonance effect of millimeter waves in the power range from 10-19 to 3 × 10-3 W/cm2 on Escherichia coli cells at different concentrations

The effect of millimeter waves (MMWs) on the genome conformational state (GCS) of E. coli AB1157 cells was studied by the method of anomalous viscosity time dependencies (AVTD) in the frequency range of 51.64-51.85 GHz. The 51.755 GHz resonance frequency of the cell reaction to MMWs did not depend on power density (PD) in the range from 10^-19 to 3 × 10^-3 W/cm². The half-width of the resonant reaction of cells showed a sigmoid dependence on PD, changing from 3 MHz to 100 MHz. The PD dependence of the half-width had the same shape for different concentrations of exposed cells (4 × 10⁷ and 4 × 10⁸ cells/ml), whereas the magnitude of the 51.755 GHz resonance effect differed significantly and depended on the PD of MMW exposure. Sharp narrowing of the 51.755 GHz resonance in the PD range from 10^-4 to 10^-7 W/cm² was followed by an emergence of new resonance frequencies. The PD dependence of the MMW effect at one of these resonance frequencies (51.674 GHz) differed markedly from the corresponding dependence at the 51.755 GHz resonance, the power window occurring in the range from 10^-16 to 10^-8 W/cm². The results obtained were explained in the framework of a model of electron-conformational interactions. The frequency-time parameters of this model appeared to be in good agreement with experimental data. © 1996 Wiley-Liss, Inc.     

Simple method to measure power density entering a plane biological sample at millimeter wavelengths

A simple method for measuring microwave power density is described. It is applicable to situations where exposure of samples in the near field of a horn is necessary. A transmitted power method is used to calibrate the power density entering the surface of the sample. Once the calibration is available, the power density is known in terms of the incident and reflected powers within the waveguide. The calibration has been carried out for liquid samples in a quartz cell. Formulas for calculating specific absorption rate (SAR) are derived in terms of the power density and the complex dielectric constant of the sample. An error analysis is also given.     

Dependence of anti-inflammatory effects of high peak-power pulsed electromagnetic radiation of extremely high frequency on exposure parameters

A pronounced anti-inflammatory effect of high peak-power pulsed electromagnetic radiation of extremely high frequency was shown for the first time in a model of zymosan-induced footpad edema in mice. Exposure to radiation of specific parameters (35, 27 GHz, peak power 20 kW, pulse widths 400-600 ns, pulse repetition frequency 5-500 Hz) decreased the exudative edema and local hyperthermia by 20% compared to the control. The kinetics and the magnitude of the anti-inflammatory effect were comparable with those induced by sodium diclofenac at a dose of 3 mg/kg. It was found that the anti-inflammatory effect linearly increased with increasing pulse width at a fixed pulse repetition frequency and had threshold dependence on the average incident power density of the radiation at a fixed pulse width. When animals were whole-body exposed in the far-field zone of radiator, the optimal exposure duration was 20 min. Increasing the average incident power density upon local exposure of the inflamed paw accelerated both the development of the anti-inflammatory effect and the reactivation time. The results obtained will undoubtedly be of great importance in the hygienic standardization of pulsed electromagnetic radiation and in further studies of the mechanisms of its biological action.