共查询到20条相似文献,搜索用时 31 毫秒
1.
Kreshchenko N. D. Sheiman I. M. Fesenko E. E. 《Russian Journal of Developmental Biology》2001,32(2):119-123
We have studied the effect of a weak electromagnetic field on the morphogenesis of the planarian Dugesia tigrina. The regeneration of the pharynx was examined after its amputation. We have determined the rate of the appearance of the food response of a new pharynx. Experimental conditions were varied, such as dose and duration of irradiation, season, and time of irradiation after surgery. The results of experiments conducted with 2966 planarians have shown that weak electromagnetic field has various effects, which appear either as stimulation of regeneration or as its inhibition. In some experiments, there was no effect at all. These differences depend on numerous factors and may be modulated. 相似文献
2.
Electron microscopic examinations of the cerebral cortex in rabbits and rats after exposure to weak extra-low electromagnetic fields has detected ultrastructural changes whose degree in different nerve tissue elements was dependent on the duration of irradiation. Single exposure to weak extra-low electromagnetic field resulted only in the glial response of the neocortex, while multiple exposure resulted alternately in the response of glial cells or neuronal bodies. Three days after a single exposure and within 15 days after multiple exposure to electromagnetic field a complete repair of the nervous tissue was observed. No destructive or pathological alterations have been found which suggests the functional character of the reactions induced. Neuro-morphological alterations are of a similar character when induced by weak extra-low electromagnetic fields or other biophysical effects which points to common subcellular mechanisms of nonspecific adaptive reactions. 相似文献
3.
Weak electromagnetic radiation (36 GHz, 100 MicroW/cm2) was used to study its effect on learning and memory of larvae and imago of the grain beetle Tenebrio molitor. The insects were learned to choose the direction in a T-maze. The retention was tested a month later. They were exposed to weak electromagnetic radiation before or after the learning experiments. Previous exposure to weak electromagnetic radiation stimulated learning of both larvae and imago. The effect depended on the developmental stage of the larvae. It was considerably stronger in larvae exposed to weak electromagnetic radiation immediately after their molting. It was better in the first half of the instar than in the second half. It is suggested that the effect of weak electromagnetic radiation can correlate with the function of hormones of metamorphosis. 相似文献
4.
R S Budagov 《Radiobiologiia》1984,24(5):657-659
In experiments on mice it was shown that cystamine exerts its protective action not only against the concurrent effect of ionizing radiation and weak thermal injury but also against the effect of heat (burn) 48 h after irradiation with a midlethal dose (30-day-death decreased from 95 to 20%). 相似文献
5.
The effect of weak electromagnetic radiation (36 GHz, 100 mu W/cm2) on the development of the grain beetle Tenebrio molitor was studied. Insects were irradiated in different larval instars and at the pupal stage. It was found that weak electromagnetic radiation stimulated the molting and pupation of larvae and the metamorphosis of pupae. The stimulating effect of radiation was weak when animals were exposed in the initial period of the instar and the pupal stage and was more pronounced if the irradiation was carried out in the second half of the current instar and the pupil stage. The effect of weak electromagnetic radiation on the development of beetle can be related to the function of the hormones of metamorphosis. 相似文献
6.
Tumor-treating fields (TTFields) are low-intensity and intermediate-frequency alternating electric fields that have been found to inhibit tumor cell growth. While effective, the mechanism by which TTFields affect cell growth is not yet clearly understood. Although numerous mathematical studies on the effects of electromagnetic fields on single cells exist, the effect of TTFields on single cells have been analyzed less frequently. The goal of this study is to explore through a mathematical analysis the effects of TTFields on single cells, with particular emphasis on the thermal effect. We examine herein two single-cell models, a simplified spheroidal model and a simulation of a U-87 MG glioblastoma cell model obtained from microscopic images. A finite element method is used to analyze the electric field distribution, electromagnetic loss, and thermal field distribution. The results further prove that the electric field in the cytoplasm is too weak and its thermal damage can be excluded as a mechanism for cell death in TTFields. Bioelectromagnetics. 2020;41:438–446. © 2020 Bioelectromagnetics Society. 相似文献
7.
Konovalov VF Serikov IS 《Radiatsionnaia biologiia, radioecologiia / Rossi?skaia akademiia nauk》2001,41(2):207-209
The modifying influence of the weak electromagnetic field on the development of the audiogenic spasmodic activity in rats was shown. The decrease of lifetime of experimental rats exposed to electromagnetic fields with different parameters and development of tumours (in one set of experiments) was found. 相似文献
8.
The role of nonsteady phenomena determined by a low velocity of ion movements in a weak external field is considered in relation to their possible nonlinear effects on processes occurring in boundary layers near the membrane, particularly, on the release of membrane-bound proteins and pH value. It is shown that a short-term treatment of wheat seeds with low-frequency magnetic field at the stage of esterase activation during seed swelling enhances the activation of esterases; the effect observed at final stages of activation depends on the time after the treatment with electromagnetic field. Treatment of seeds with electromagnetic field at this stage changed qualitatively the time course of the release of reaction products into the medium: the reaction rate increased initially and then decreased below the control level. At earlier stages of swelling in treated seeds and at all stages in control seeds, the time course of the product release was linear. The retardation of the release of the reaction products at terminal stages of esterase activation is presumably related to the release of proteins and their complexes under the action of electromagnetic field and the resulting restoration of the barrier properties of membranes. Treatment with electromagnetic field also caused a noticeable acceleration of proton flow form the medium, which was judged from pH changes in the bulk medium and in the vicinity of germ surface. The difference between the treated and control samples after 23-24 h of imbibition became statistically significant and was as high as 0.4 pH units. By taking into account the nonsteady phenomena occurring upon action of low-frequency electromagnetic field, it is possible to explain unusual dependences of biological effects on the amplitude of the electromagnetic field, including the atypical enhancement of these effects by the action of weak low-frequency fields. 相似文献
9.
K. L. Kovács 《Origins of life and evolution of the biosphere》1981,11(1-2):37-52
A novel approach has been introduced to detect the manifestation of symmetry breaking weak interactions at molecular level. In the racemic conglomerate crystallization of D, L-sodium-ammonium tartrate the effect of32P irradiation was studied by measuring the weight and optical purity of the crystalline phase as well as the size distribution of the crystallites. The high number of independent experiments (over 1000) permitted statistical analysis of the results. The following observations have been made:
- Beta irradiation influences the crystallization process, irradiated samples yield more crystalline material.
- The effect involves presumably crystal seed formation because from the irradiated solutions more and smaller crystallites are formed.
- The presence of beta particles induces stereoselective crystallization, the crystalline phase shows optical activity characteristic of the “unnatural” L-isomer.
- The above changes are attributed to the beta irradiation as the magnitude of the effects depends on the amount of added radioactivity. Optically active contaminants are highly unlikely sources of the differences between irradiated and control series.
- In the absence of32P the tartrate enantiomers have equal probability to form crystals, i.e., the contribution of mixing of weak interaction into the electromagnetic one is not measurable in this system.
10.
研究了微波和电场对蒙古裸腹溞存活、生长和生殖的影响.结果表明: 35 s以上的2 450 MHz的微波辐照对蒙古裸腹溞的致死效应明显.短时间(<25 s)微波处理显著提高了蒙古裸腹溞的每窝产幼量及一生产幼量,其中10 s微波处理组一生产幼量最高.微波处理使蒙古裸腹溞的寿命显著延长(总寿命15.8~18 d).短时间的微波处理对幼溞的发育无显著影响,但对成溞的生长具有一定的抑制作用.脉冲电场可大幅提高蒙古裸腹溞的一生产幼量, 其中29 kV·cm-1的脉冲电场效果最佳; 高压静电场对蒙古裸腹溞的繁殖无显著影响.高压静电场和脉冲电场对幼溞的发育均无显著影响,高压静电场对成溞的生长影响不明显,而脉冲电场则对成溞的生长具有一定的抑制作用,且电压越高,抑制作用越明显. 相似文献
11.
The effect of pulsed electromagnetic fields on the electrical potential and two-way flux of Na+ across the epithelium of the rabbit colon in vitro was investigated. In control experiments the transepithelial mucosal-to-serosal and serosal-to-mucosal fluxes (Jm----s and Js----m) were constant over the experimental period. When the epithelium was at right angles to the applied electromagnetic field, the Jm----s flux of Na+ was reduced, whereas Js----m was enhanced. When the epithelium was rotated 180 degrees, Jm----s was enhanced, whereas Js----m was reduced. When the epithelium was mounted parallel to the magnetic field, both Jm----s and Js----m of Na+ were increased, the latter continuing to increase after the field was turned off. When the tissue was rotated 180 degrees, the same enhanced flux was observed, but now the Jm----s flux showed the greatest increase, which again occurred in the period after the field was turned off. The rate of decrease of transepithelial potential difference in all orientations was less than the control. Also, the conductance increased in orientations 2-4 and decreased in orientation 1 after the field had been applied. This suggests that pulsed electromagnetic fields can have a direct effect on the movement of Na+ across tissue and transepithelial potentials. The mechanism may depend on several factors, such as induced changes in certain ion pumps, the membrane potential, and the surface charge of cell wall proteins. 相似文献
12.
Sunkari VG Aranovitch B Portwood N Nikoshkov A 《Electromagnetic biology and medicine》2011,30(2):80-85
The aim of this study was to test if an extremely weak 1?GHz electromagnetic field (EMF), known to be in resonance with clusters of water molecules, has biological effects on human fibroblasts. We demonstrated that in an in vitro model of wound healing, this EMF can activate fibroblast migration. [(3)H]thymidine incorporation experiments demonstrated that the EMF could also activate fibroblast proliferation. Activation of the expression of human fibroblast growth factor 1 (HFGF1) after EMF exposure showed that molecular wound healing pathways are activated in response to this water-resonant EMF. 相似文献
13.
《人体电磁兼容系统与电磁场处理水》一文分三篇写。第一篇“Ⅰ.人体电磁兼容系统”,讨论了人体体内电磁场;第二篇“Ⅱ·电磁水的特性”,讨论了电磁水的电磁场。二文均已发表于《生物磁学》。本文是第三篇,讨论电磁水电磁场对人体电磁场的作用,重点阐明饮用电磁水后,主要是电磁水的电磁场作为入射场与体内场发生迭加作用,产生耦合电磁场,从而实现其对体内场的调节作用,达到维系身体健康的目的。由于有关水的问题非常复杂,动态性强,故大多数关于耦合场的研究均服从于“统计学规律”。 相似文献
14.
A theoretical model of the mechanism of action of weak electromagnetic fields on water solutions has been constructed. The model predicts the redistribution of protons on spatial inhomogeneities in water medium. It is shown that an external field leads to the phasing of ions on the standing wave, which is considered as an inhomogeneity. As a result of an inhomogeneous distribution of hydrogen ions, local regions with a higher and lower acidity arise. The acidity of medium substantially affects the rate of chemical reactions; therefore, the exposure to a weak external field can change this parameter. The effect of local changes in acidity on the rate of hydrogen peroxide production was considered. It was predicted that the exposure to a weak electromagnetic field with particular parameters can increase the rate and, as a consequence, the concentration of hydrogen peroxide in solution. 相似文献
15.
The effect of heterosis was studied in several quantitative traits of clone breed and interbreed silkworm hybrids exposed to electromagnetic irradiation (lambda = 1.6 cm, power density 700 microW/cm2) during postdiapause embryonic development. The influence of the type of reproduction on the manifestation of irradiation effects in the next generation was also examined. In hybrids, the resistance to low-intensity high-frequency irradiation was higher than in the parental forms. Unlike the latter, the hybrids showed no significant modification of the traits after the exposure to electromagnetic irradiation. In the second generation, the modifying effect of irradiation is retained in the case of parthenogenetic silkworm development but not after mating. 相似文献
16.
The effect of ultrahigh-frequency electromagnetic radiation on learning and memory processes] 总被引:2,自引:0,他引:2
I N Krylova A S Dukhanin A B Il'in E Iu Kuznetsova N V Balaeva N L Shimanovski? Iu P Pal'tsev V V Iasnetsov 《Biulleten' eksperimental'no? biologii i meditsiny》1992,114(11):483-484
Low-intensity electromagnetic field (12.6 cm, 2375 MHz, power density 1 mW/cm2) produced retrograde amnesia in the rat passive avoidance test. No effect was registered of microwave irradiation on the open field behavior and the pain sensitivity. Functional activity of the m-cholinergic receptors decreased, but their number increased in the brain cortex. It is suggested that cholinergic system plays an important role in the effects of electromagnetic field on memory processes. 相似文献
17.
It was shown that biologically active substances formed in the liver tissue under the effect of hypoxia and SHF electromagnetic radiation produce a radioprotective effect when administered 15 min before exposure and have no protective effect when administered after irradiation. 相似文献
18.
《Electromagnetic biology and medicine》2013,32(2):80-85
The aim of this study was to test if an extremely weak 1 GHz electromagnetic field (EMF), known to be in resonance with clusters of water molecules, has biological effects on human fibroblasts. We demonstrated that in an in vitro model of wound healing, this EMF can activate fibroblast migration. [3H]thymidine incorporation experiments demonstrated that the EMF could also activate fibroblast proliferation. Activation of the expression of human fibroblast growth factor 1 (HFGF1) after EMF exposure showed that molecular wound healing pathways are activated in response to this water-resonant EMF. 相似文献
19.
Effect of modified SHF and acoustic stimulation on spectral characteristics of the electroencephalograms of the cat brain 总被引:1,自引:0,他引:1
The effect of modulated electromagnetic fields on the spectral parameters of bioelectric brain activity in awake cats was studied by registering the electroencephalogram from the skin surface in the vertex area using carbon electrodes. In the normal electroencephalogram, spectral components in the range above 20 Hz predominated. It was shown that, upon irradiation with electromagnetic field (basic frequency 980 MHz, power density 30-50 microW/cm2), spectral components in the range of 12-18 Hz begin to prevail. A similarity in the redistribution of the power of spectral components upon both acoustic and modulated electromagnetic influences was revealed. The results suggest that there is a a common neurophysiological mechanism by which modulated electromagnetic radiation and acoustic stimulation affect the electrical activity of the brain. This ia consistent with the assumption that the effect of the electromagnetic field on the central nervous system is mediated through the acoustic sensory system. 相似文献
20.
Y Hiraki N Endo M Takigawa A Asada H Takahashi F Suzuki 《Biochimica et biophysica acta》1987,931(1):94-100
Pulsed electromagnetic fields promote healing of delayed united and ununited fractures by triggering a series of events in fibrocartilage. We examined the effects of a pulsed electromagnetic field (recurrent bursts, 15.4 Hz, of shorter pulses of an average of 2 gauss) on rabbit costal chondrocytes in culture. A pulsed electromagnetic field slightly reduced the intracellular cyclic adenosine 3',5'-monophosphate (cAMP) level in the culture. However, it significantly enhanced cAMP accumulation in response to parathyroid hormone (PTH) to 140% of that induced by PTH in its absence, while it did not affect cAMP accumulation in response to prostaglandin E1 or prostaglandin I2. The effect on cAMP accumulation in response to PTH became evident after exposure of the cultures to the pulsed electromagnetic field for 48 h, and was dependent upon the field strength. cAMP accumulation in response to PTH is followed by induction of ornithine decarboxylase, a good marker of differentiated chondrocytes, after PTH treatment for 4 h. Consistent with the enhanced cAMP accumulation, ornithine decarboxylase activity induced by PTH was also increased by the pulsed electromagnetic field to 170% of that in cells not exposed to a pulsed electromagnetic field. Furthermore, stimulation of glycosaminoglycan synthesis, a differentiated phenotype, in response to PTH was significantly enhanced by a pulsed electromagnetic field. Thus, a pulsed electromagnetic field enhanced a series of events in rabbit costal chondrocytes in response to PTH. These findings show that exposure of chondrocytes to a pulsed electromagnetic field resulted in functional differentiation of the cells. 相似文献