共查询到20条相似文献,搜索用时 31 毫秒
1.
L. R. Yeganyan R. E. Muradyan F. H. Arsenyan G. K. Bazikyan S. N. Ayrapetyan 《The Environmentalist》2012,32(2):236-241
There are many data about the extremely low-frequency electromagnetic fields (ELF-EMF) therapeutic use, especially in the
field of oncology. Recent data suggest that 4 Hz EMF having dehydration effect on tissues has a pronounced antitumor activity
on sarcoma-180 in mice. It was shown that 4 Hz EMF have pronounced effects on physicochemical properties of water and water
solution. Therefore, the aim of the present work was the comparative study of the modulation effect of ELF-EMF on cisplatin-induced
changes cell hydration and number of ouabain receptors in membrane of sarcoma-180 tumor tissues. Tissue hydration was measured
as wet weight/dry weight and expressed as a water content of g/g in dry weight. The number of 3H-ouabain receptors in membrane was counted by isotope scintillation counter. In conclusion, ELF-EMF can be a possible tool
for stimulation of cisPt antitumor effect. 相似文献
2.
Summary Biological effects of extremely low-frequency electromagnetic fields (ELF-EMF) on microcirculation were investigated in vivo by monitoring arteriole diameters in conscious mice. Measurements of blood vessel diameter were monitored 33 min non-stop
before during and after exposure with ELF-EMF and every 389 ms blood vessel diameter were calculated.
Using a dorsal skinfold chamber (DSC), and following caudal vein injection of FITC-dextran 250 kDa, the microvasculature (initial
arteriole diameter of 45–80 μm), was examined by intravital microscopy and video images were recorded for a total time of
33 min. Arteriole diameter was continuously measured by on-line analysis using a High-speed Digital Machine Vision System
CV-2100, using an edge-gap detection algorithm. Since vessel diameters exhibit rhythmic variation expressed by vasomotion,
for estimation of microcirculatory activity we used both raw data for frequency analysis of vasomotion (measured frequencies
of vasomotion were in the range 0.008÷0.1 Hz) and evaluate mean blood vessel diameter for each 1 min period of time, and make
a comparison between Pre, Exposure/Sham exposure and Post exposure periods, with the aim to evaluate possible changes in mean
blood vessel diameter as a result of ELF-EMF action.
During EMF exposure and post-exposure periods, arteriole diameters increased significantly compared with the pre-exposure
period, and the changes were larger during post-exposure. In contrast to sham exposure, vasodilatation of the microvasculature
was significantly greater during exposure and post-exposure to 16 Hz EMF. These findings suggest that ELF-EMF may have potential
therapeutic use benefit for treating vascular disorders. 相似文献
3.
Y. R. Mikayelyan N. S. Baghdasaryan A. K. Nikoghosyan S. V. Barseghyan S. N. Ayrapetyan 《The Environmentalist》2012,32(2):179-187
The effects of extremely low-frequency electromagnetic field (ELF EMF) and ELF-modulated millimeter waves (MMW) on physicochemical
properties of physiological solution (PS) at different environmental medium were studied. The existence of frequency “windows”
at 4 Hz and 8 Hz frequencies of ELF EMF and ELF-modulated MMW which have different effects on heat fusion period (HFP), hydrogen
peroxide (H2O2) formation and oxygen (O2) content of water solution and different dependency on temperature, background radiation (BGR) and illumination was shown.
The obtained data allow us to suggest that cell bathing medium serving as a target through which the biological effects of
ELF EMF and ELF-modulated MMW on cells are realized is extra sensitive to environmental factors. Therefore, the variability
of experimental data on EMF biological effects, obtained in different laboratories can be explained by different environmental
conditions of experiments, which very often are not considered adequately. 相似文献
4.
Regulation of microcirculation and other physiological processes have strong non-linear character and involves complex of
different processes, every process with own hierarchy in time and different frequencies. Traditional Fourier analysis does
not provide sufficient power and resolution to elucidate characteristic of low vasomotor frequencies. Therefore, we apply
a Time–frequency (wavelet) analysis on the signal obtained by Laser Doppler flow meter (LDF) at 25 healthy volunteers, exposed
at the same time to low frequency electromagnetic fields, used for physiotherapy. Signal processing include Matlab based algorithms
for digital signal processing (DSP) and Matlab Spectral analysis toolbox of simultaneous registered variations in Blood Pressure
(BP), Laser Doppler Flow (LDF), and Intravital microscopy (IVM). It provides useful information about regulatory mechanisms
and vegetative nervous system regulation of peripheral blood flow. Continuous changes in blood pressure variations and perfusion
of extremities were measured prior and after 10, 20, and 30 min ELF-EMF (10, 16, 20, and 30 mT), exposure. After wavelet analysis
of the blood flow signals and vasomotion changes signals, several frequency bands were distinguished: 0.0095–0.02 Hz; (α),
0.02–0.06 Hz; (β), 0.06–0.15 Hz; (γ), 0.15–0.4 Hz; (δ), and 0.4–1 Hz; (θ) for LDF data and 0.0095–0.4 Hz; (α), 0.4–0.75 Hz;
(β), 0.75–0.9 Hz; (γ), 0.9–1.2 Hz; (δ), and 1.2–2 Hz; (θ) for IVM data. In this study, overlapping of some frequency bands
between IVM and LDF data were found. Overlapping of the frequency bands has two ways of interpretation, one related with similarity
of the structures and tissues and other related with output of ELF-EMF stimulation. We used also correlation and cross-correlation
analysis to compare non-invasive (BP measurements and LDF) data, with invasive intravital microscopy (IVM) data (obtained
on animals in vivo), during ELF-EMF stimulation. IVM data were used as a reference value, for certain information of possible
mechanisms of biological response at the tissue and blood vessel level after ELF-EMF exposure with frequency in the range
from 10 to 50 Hz and magnetic flux density of 20 mT. Comparative analysis of IVM and LDF, frequency bands show that they have
statistical significant changes after ELF-EMF stimulation. Five subintervals were confirmed (α-, β-, γ-, δ-, and θ). The findings
indicate that local ELF-EMF exposure at the constant temperature of the media increases skin blood flow at the upper extremities
which have a contribution to the α-frequency band at IVM. 相似文献
5.
The present study investigated the influence of electromagnetic fields (EMF), similar to that emitted by mobile phones, on
brain activity. Ten women and ten men, matched for age and educational level, performed a short memory task (Wechsler test),
with simultaneous Electroencephalogram (EEG) recordings at 15 scalp electrodes, both without (baseline) and with exposure
to an 1,800 MHz signal. The EEG energy was found concentrated at the four basic EEG bands [α (8–13 Hz), β (14–30 Hz), δ (0–4 Hz), and θ (5–7 Hz)]. The analysis revealed that in the presence of EMF, the energy of the β band was significantly greater for females than for males at the majority of the electrodes. Since beta oscillation is associated
with the shift of attention during the perception, these findings may indicate that the particular EMF (1,800 MHz signal)
exerts an influence on this brain activity, which appears to be gender-related. 相似文献
6.
Gayane Ayrapetyan Anahit Grigoryan Erna Dadasyan Sinerik Ayrapetyan 《The Environmentalist》2007,27(4):483-488
The effects of 4 Hz extremely low frequency Electromagnetic Fields (ELF EMF), Infrasound (IS) and hydrogen peroxide (H2O2) on Na+–K+ pump-induced transient inhibition of heart muscle contractility was studied. It was documented that EMF-treated and H2O2-containing physiological solution had synergic depressing effect on Na+–K+ pump-induced inhibition of muscle contractility, while the IS had elevation effect on it. On the basis of the obtained data
the H2O2 could be suggested as the messenger through which the stimulation effect of EMF on heart muscle is realised, while the relaxing
effect of IS on heart contractility is due to the decrease of CO2 solubility of muscle bathing aqueous medium. 相似文献
7.
Eleni Nanou Vassilis Tsiafakis E. Kapareliotis Charalabos Papageorgiou Andreas Rabavilas Christos Capsalis 《The Environmentalist》2005,25(2-4):173-179
Summary The effects of electromagnetic fields (EMF) emitted by cellular phones on human electroencephalogram (EEG) were studied during
an auditory memory task. The experimental method and the experimental setup are introduced as a credible measurement method
of EEG. 19 normal subjects (10 women and 9 men) performed the memory task both with and without exposure to a 900 MHz signal,
emitted by a dipole antenna placed near the subjects' head. The energy of the EEG signals was calculated at the time domain.
A Fourier transform of the EEG signals was done and the EEG energy was also calculated at the frequency domain. As the Parseval's
theorem anticipates the energies were identical. The EEG energy was found concentrated at the four basic bands (α (8–13 Hz),
β(14–30 Hz), δ (0–4 Hz) and θ(5–7 Hz)). The primary concern of the present study was the gender related influence of EMF on
the spectral energy of EEG. The results show evidence of a strong gender—radiation interaction effect on the EEG energy and
on the peak amplitudes within each of the four rhythms. Without radiation the spectral power of males is greater than of females,
while under exposure the situation is reversed. Under the influence of EMF the spectral power of the males EEG is decreased
while that of the females is increased. In conclusion both the baseline EEG and the changes effected to the EEG power spectrum
under the influence of EMF seem to be gender dependent. 相似文献
8.
Erna Dadasyan Gayane Ayrapetyan Naira Baghdasaryan Yerazik Mikayelyan Sinerik Ayrapetyan 《The Environmentalist》2012,32(2):166-174
It was shown that the 4 Hz 30 dB mechanical vibration (MV) of physiological solution (PS) had modulation effect on snail heart
contractility. However, the nature of metabolic pathway of MV-treated PS-induced effect is not clear yet. It was suggested
that the MV-induced modulation of water molecules dissociation leads to the variation of reactive oxygen species’ level in
cell bathing medium, which could serve as a messenger for switching on the metabolic pathway(s) responsible for modulation
of muscle contractility. The aim of present work was to check this hypothesis and to elucidate the metabolic pathway through
which the effect of MV-treated PS on heart contractility was realized. For this purpose, the effect of MV on heat fusion periods
(HFP) and H2O2 content in PS, as well as on heart contractility, 45Ca2+ efflux, intracellular levels of cGMP and cAMP, muscle hydration, and ouabain binding were studied. It was shown that MV treatment
of PS increased the HFP-(21.33 ± 4%) and decreased the H2O2 content-(5 ± 0.9%). The intracardiac perfusion by MV-treated PS increased the amplitudes of heart contractility, which was
accompanied by the increasing of 45Ca2+ efflux (252.4 ± 16%), elevation of cGMP’s level (42.05 ± 7%), decreasing of cAMP’s level (82.67 ± 7%), increasing of the
tissue hydration (18.64 ± 3%), and increasing of the number of ouabain binding sides (25 ± 4%). It was suggested that MV-induced
increasing of heart muscle contraction amplitudes is due to the decreases of H2O2 content in the medium, which leads to the elevation of heart muscle contractility in result of activation of cGMP-dependent
Na+/Ca2+ exchange in forward regime. 相似文献
9.
This study is aimed to clarify whether effect of low-level microwave radiation on human brain differs at different modulation
frequencies. Resting EEG recordings were done on different groups of healthy volunteers. The 450 MHz microwave radiation modulated
at 40 and 70 Hz (15 subjects) and 217 and 1,000 Hz (19 subjects) frequencies was applied. The results of our previous study
at 7, 14 and 21 Hz modulation were included into analysis. Ten cycles of the exposure (1 min off and 1 min on) at each fixed
modulation frequencies were applied. The field power density at the scalp was always 0.16 mW/cm2. Our results showed that microwave exposure increased the EEG energy at EEG frequencies lower or close to the modulation
frequency. No effect was detected at EEG frequencies higher than the modulation frequency. Statistically significant changes
were caused by exposure in the EEG alpha and beta frequency bands; no significant effect was detected in the theta band. Our
results suggest that telecommunication devices with complex spectrum of modulation frequencies like mobile phone can affect
all human EEG frequency bands. 相似文献
10.
J. J. M. Cuppen G. F. Wiegertjes H. W. J. Lobee H. F. J. Savelkoul M. A. Elmusharaf A. C. Beynen H. N. A. Grooten W. Smink 《The Environmentalist》2007,27(4):577-583
A hypothesis is proposed how Low Frequency Electromagnetic Field (LF EMF) exposure can stimulate an immune response, based
on recent insights in immunology. We hypothesize that the Immunent EMF treatment induces mild stress to cells, which then
produce cytokines that function as alarms or so called danger signals for the immune system. In this way EMF treatment takes
the place of multiplying pathogens, and the damage these cause, in the triggering of an immune response. In a first series
of experiments in␣vitro common carp head kidney-derived phagocytes were used to determine ROS production as a measure for
immune activation. Exposure to LF EMF signals (200–5,000 Hz) at 5 μT or 1.5 mT led to 42 or 33% increase in immune activity,
respectively, compared to negative control values. EMF could also additionally stimulate chemically pre-stimulated samples
up to 18% (5 μT) or 22% (1.5 mT). Significance of increase in ROS production in the total series was: p < 0.0001. In a second series of experiments in␣vitro commercial goldfish were used. Groups of fish were housed under equal
conditions in at least four control tanks and 8–16 EMF-exposed tanks. Exposure was done with a predominantly vertical field
at field strengths (rms) between 0.15 and 50 μT. Without treatment mortality was about 50% after 18 days, while the treatment
at 5 μT reduced it to 20% on average. At field strengths 0.15, 0.5, 1.5, 5, 15 and 50 μT an equally strong effect was found.
Reducing the field strength to 0.05, 0.06, 0.01 and 0.003 μT showed a gradually decreasing effect, which only at 0.003 μT
is no longer statistically significant. Finally, in␣vitro experiments were done with 560 commercial broiler chickens exposed
to infection pressure from coccidiosis. EMF exposure at 6.5 μT reduced intestinal lesions by 40% and improved feed conversion
by 8%. 相似文献
11.
Lyubina Vesselinova 《The Environmentalist》2012,32(2):249-255
The importance of the assessment of the electromagnetic fields /EMF/ background as a health risk factor for the physiotherapy
personnel is discussed in this paper. Wide frequency and amplitude ranges as well as large variety of design prescribed in
the rehabilitation program form complicated work conditions. In this paper, we attempt to present and classify this specific
work environment, i.e., low intensive EMF background with non homogenous frequency and modulation characteristics, stochastic
changes running during day, ground or even underground units’ placement and professional specifics, i.e., chronic EMF expositions,
personnel’s trunk and hands exposure, dose-measurement absence, lack of program for prevention and prophylaxis for the assessment
of the relatively insufficiently elucidated potential of EMF as a harmful factor for medical staff. Our “Study of the biological
effects of the EMF among medical staff from PRM wards—potential of risk reduction”/initialized in 1999/and the original survey
card structure are presented in general here first. It has been shown the importance to extend the “native” studies among
homogenous professional groups, two of them presented there, as well as the study of the biological effects of EMF in their
different aspects, especially taking into account the elevated levels of ionizing and non-ionizing radiation in the environment.
This includes the special attention on the exposure of medical staff from PRM units and creation of adequate methods for prevention
of unnecessary exposure to these physical factors. 相似文献
12.
The new recommendations of WHO and EC for legislation in Europe and other countries concerning non-ionizing radiation (NIR)
health and safety include exposure limits that are very debatable. ICNIRP Guidelines propose exposure limits for electromagnetic
fields in the frequency range up to 300 GHz based on short-term exposures and on thermal effects. The new EC proposal for
optical and laser safety legislation includes classification of sources of radiation—both lasers and other optical sources,
but not requirements for the methodology of classification. On the other hand, many new requirements have been set by the
WHO publication “Model Legislation for EMF Protection” concerning the responsibilities in the field of EMF health and safety.
Many specialists in the field of developing exposure limits have positions very far away from the proposed of the ICNIRP Guidelines
philosophy. The results are different approaches in developing standards and exposure limits, and differences more than 100
times in maximal permissible levels. We, the Bulgarian Program Committee on NIR, try to organize working groups and discuss
different philosophy for developing exposure limits for more than 10 years. This paper exposes our position in this area. 相似文献
13.
Anna Suhhova Maie Bachmann Jaanus Lass Deniss Karai Hiie Hinrikus 《The Environmentalist》2009,29(2):210-214
This study is aimed to investigation of the effect of modulated 450 MHz microwave radiation on the EEG inter-hemispheric asymmetry.
Ten cycles of the microwave exposure (1 min off and 1 min on) at fixed modulation frequency were applied on two groups of
healthy volunteers. The first group of 13 subjects was exposed to microwave radiation modulated at 14 Hz and the second group
of 15 subjects at 40 Hz frequency. The peak specific absorption rate (SAR) average over 1 g was 0.303 W/kg. Differences in
SAR between hemispheres were up to 20 dB. Rod antenna was located from the left side of the head. Differences of relative
changes in EEG energy between symmetric channels FP1–FP2, T3–T4, P3–P4 and O1–O2 in exposed and sham conditions were analysed.
The results showed increase in EEG energy from the left side caused by microwave exposure. Statistical analysis done for the
whole group of subjects didn’t reveal significant differences in inter-hemispheres asymmetry between exposed and sham conditions.
However, statistical analysis performed for individual subjects detected significant differences in asymmetry caused by exposure
for 15–35% of individuals. 相似文献
14.
Summary In an effort to explain the benefit of therapeutic use of electromagnetic fields (EMF) a systemic effect has been proposed
by us. To assess the efficacy of this approach, an objective biochemical approach was developed. Ten patients with Reflex
Sympathetic Dystrophy (RSD) were clinically evaluated, and lymphocytes were isolated from their blood samples obtained before
and after exposure of the uninvolved limb to an EMF. Utilizing a SpectraCell method that includes radio labeled molecules
and protein-free media for culturing the lymphocytes, an elevation of the content of fructose, serine, glycine, and calcium
cellular metabolic uptake were found following in the culture to EMF in comparison with non-exposed lymphocytes (p < 0.01). In addition, the pain level was determined by a conventional visual analogue scale (VAS) before and after EMF exposure,
evidencing a significant pain relief. Specifically, after exposure to 120 pps semi sinewave, 1500Gauss EMF, generated by a
THERAMAG∘ledR device, an improvement in the flexibility of the limb and a reduction in swelling of the affected extremity were detected
clinically. These findings are in concert with the new hypothesis that, with relief of pain, lymphocytes are predominately
altered in their cell cycle from M phase to S phases associated with increased structuring of intracellular water. A consideration
of the basic understanding of the role lymphocytes may be inferred from this preliminary study. An extensive review of the
literature on the basic science and therapeutic use of magnetic fields in humans is provided in an attempt to understand the
relevance of magnetic therapy of specific pain syndromes. 相似文献
15.
This article highlights recent research on the beneficial use of selected low frequency electromagnetic fields (EMF) as a
safe alternative therapy for treatment of cancer and other health problems. It is shown that EMF therapy provides a safe alternative
and adjunct modality for the treatment of cancer and other health problems, and therefore, research in this field deserves
more support. The paper also discusses some reports and hypothesis of potential risk of human exposure to low frequency EMF,
mainly to the power line frequency of 60 Hz. 相似文献
16.
Mehri Kaviani Moghadam Saied Mohammad Firoozabadi Mahyar Janahmadi 《The Environmentalist》2008,28(4):341-347
In spite of growing concern about the influence of magnetic fields on biological systems, the interaction between extremely
low frequency magnetic field (ELF magnetic fields) and biological structures at the cellular level remains obscure. The aim
of this study was to investigate if 50 Hz magnetic fields could have an effect on the neuronal excitability and firing responses.
Under Current-Clamp condition, exposure to 50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities resulted in an increase
in the peak amplitude of action potential and after hyperpolaization potential in a time dependent manner. Both magnetic field
intensities decreased also the firing frequency and the duration of action potential. Taken together, these data suggest that
50 Hz ELF magnetic fields at 2 mT or 0.8 mT intensities may change the electrophysiological behavior of neuronal cells and
underlying ion channel currents. 相似文献
17.
Although the biological effect of non-ionizing (NIR) and ionizing radiation (IR) on plant seed potential is well documented,
the mechanism of this impact is not clear yet. Since cell hydration, a fundamental parameter for determining cell function,
is magneto-sensitive, in present work, a comparative study of extremely low frequencies (ELF) electromagnetic field (EMF),
ELF EMF-modulated millimeter waves, and radiation exposure effects on winter wheat seeds water absorption and dry mass changes
was performed. The seeds were incubated in physiological solutions (PS) for 2 and 72 h. In case of 2-h incubation, the water
absorption determined by osmotic gradients between seeds and bathing medium, PS treated by all these factors leads to changes
of water absorption. While in case of 72-h incubation (when germination processes are in active state) these impact had reversed
character. The obtained data strongly suggest seeds bathing medium as a target through which the biological effects of NIR
and IR are realized. 相似文献
18.
Changes of Surface Properties of Yeast Cell Wall Under Exposure of Electromagnetic Field (40.68 MHz) and Action of Nystatin 总被引:1,自引:0,他引:1
S. I. Voychuk E. N. Gromozova P. M. Lytvyn V. S. Podgorsky 《The Environmentalist》2005,25(2-4):139-144
Summary Changes of the surface properties were studied in the cell wall of the yeast Saccharomyces cerevisiae Y-517 under influence of the electromagnetic field (EMF) (40.68 MHz) and lethal doses of the fungicidal antibiotic nystatin
(10 μg/106 cells). Atomic force microscopy was used to study surface topography and visco-elastic properties of the cell walls. Surface
carbohydrates were detected by lectins marked with gold with the help of the scanning electron microscope. Additional polysaccharide
layer appeared over cell surface after EMF exposure. We suggest that electromagnetic fields resulted in the change of the
cell surface, and, accordingly, the sensitivity of organisms to the antifungal antibiotics. 相似文献
19.
Maie Bachmann Ruth Tomson Jaan Kalda Maksim Säkki Jaanus Lass Viiu Tuulik Hiie Hinrikus 《The Environmentalist》2007,27(4):511-517
This study was aimed to investigate the changes in the human electroencephalographic (EEG) signal caused by modulated low-level
microwaves. The 450 MHz microwave exposure modulated at 40 Hz and 70 Hz frequencies was applied to a group of 15 volunteers.
The field power density at the scalp was 0.16 mW/cm2. Ten cycles of the exposure (1 min on and 1 min off) at both modulation frequencies were applied. Analysis of the EEG signal
was performed using three different methods: nonlinear method of scaling analysis for length distribution of low variability
periods (LDLVP), relative changes in EEG energy (S-parameter) and beta ratio (H-parameter). The analysis revealed significant changes caused by microwave for the whole group (H-parameter method). The exposure caused increase of the EEG beta power (S-parameter method). Statistically significant changes in EEG were detected for four subjects (26.7%) at 40 Hz modulation frequency
(LDLVP method). 相似文献
20.
Chiyoji Ohkubo Hideyuki Okano Akira Ushiyama Hiroshi Masuda 《The Environmentalist》2007,27(4):395-402
Authors review the importance of studying the effects of electromagnetic fields (EMF) on microcirculatory system, especially
in respect of possibility that vasculature may have direct and indirect role in interaction of static magnetic fields (SMF).
We outline the physiological importance of microcirculation and relatively new methods of evaluation technique in vivo and
explain in details the local and/or whole body exposure effects of SMF with␣range of 0.3–180 mT, power frequency EMF with
range of 0.1–30 mT and microwaves at 1.5 GHz with range 0.08–8 W/kg brain average specific absorption rate (SAR) on microcirculatory
systems in different tissues in experimental animals. 相似文献