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1.
Novikov VV  Fesenko EE 《Biofizika》2001,46(2):235-241
It was shown that weak combined magnetic fields (constant field 25-130 microT; variable field 0.01-0.2 microT; the range of effective frequencies of the alternating component 1-10 Hz) substantially increase the rate of hydrolysis of some proteins and peptides (eight various sequences). The concentration dependence of the dynamics of the process and the dependence of the magnitude of the effect on the parameters of the magnetic field. It was found that: (1) the effect is transmitted through a solvent preliminarily treated by magnetic fields and (2) the effect occurs in the presence of inhibitors of proteases and enzymes inactivating peroxides (catalase and horse radish peroxidase with substrate).  相似文献   

2.
Interaction between weak low frequency magnetic fields and cell membranes   总被引:12,自引:0,他引:12  
The question of whether very weak low frequency magnetic fields can affect biological systems, has attracted attention by many research groups for quite some time. Still, today, the theoretical possibility of such an interaction is often questioned and the site of interaction in the cell is unknown. In the present study, the influence of extremely low frequency (ELF) magnetic fields on the transport of Ca(2+) was studied in a biological system consisting of highly purified plasma membrane vesicles. We tested two quantum mechanical theoretical models that assume that biologically active ions can be bound to a channel protein and influence the opening state of the channel. Vesicles were exposed for 30 min at 32 degrees C and the calcium efflux was studied using radioactive (45)Ca as a tracer. Static magnetic fields ranging from 27 to 37 micro T and time varying magnetic fields with frequencies between 7 and 72 Hz and amplitudes between 13 and 114 micro T (peak) were used. We show that suitable combinations of static and time varying magnetic fields directly interact with the Ca(2+) channel protein in the cell membrane, and we could quantitatively confirm the model proposed by Blanchard.  相似文献   

3.
It has been shown that exposure to weak combined permanent (42 mT) and low-frequency (3-60 Hz) alternating (0.001-0.06 mT) magnetic fields changes the intensity of fluorescence of water and water-salt solutions. The gel filtration of solutions of inorganic salts treated with magnetic fields gives rise to intensively fluorescing fractions. Control solutions not exposed to electromagnetic waves do not exhibit these effects. The results obtained suggest that treatment with weak electromagnetic fields induces structural changes of water solutions, and the manifestations of these changes depend on the conditions of chromatography and chemical composition of solutions under study.  相似文献   

4.
The effects of low intensity, low frequency magnetic fields (MFs) on catalytic activity of the calcium dependent protease calpain was determined following the enzyme activation both in "in vitro" and "in vivo" conditions. We have observed that a 0.3 mT MF induces a significant increase in the requirement of the protease for this metal ion. This change is detectable at low [Ca(2+)] and disappears when the level of Ca(2+) is raised to saturating amounts. The observed effects are not due to transient MF(-) induced conformational changes occurring in calpain, but to direct effects of the MF on Ca(2+) ions, which become less available for the binding sites present in calpain. Altogether, these results indicate that exposure to low intensity, low frequency MFs alters the intracellular Ca(2+) "availability," thereby modifying the related cell response.  相似文献   

5.
It was shown that water with additions of Ca2+, Na+, K+ and Cl- ions preliminarily treated with weak combined constant (42 microT) and low-frequency alternating (0.06 microT) magnetic fields affects the intrinsic fluorescence of bovine serum albumin, the magnitude of the effect being dependent on the frequency of the alternating field and ionic composition of the aqueous salt solution. A practically complete transfer of the effect through a small portion of the solution treated with magnetic fields was revealed. It was also found that after magnetic treatment, the solution contains a rather large (molecular mass 700-900 D) and stable molecular associate, which possesses, at least partially, the properties and characteristics inherent in the whole solution that were as acquired as a result of magnetic treatment.  相似文献   

6.
Mechanisms by which weak electromagnetic fields may affect biological systems are of current interest because of their potential health effects. Lednev has proposed an ion parametric resonance hypothesis (Lednev, 1991, Bioelectromagnetics, 12:71-75), which predicts that when the ac, frequency of a combined dc-ac magnetic field equals the cyclotron frequency of calcium, the affinity of calcium for calcium-binding proteins such as calmodulin will be markedly affected. The present study evaluated Lednev's theory using two independent systems, each sensitive to changes in the affinity of calcium for calmodulin. One of the systems used was the calcium/calmodulin-dependent activation of myosin light chain kinase, a system similar to that previously used by Lednev. The other system monitored optical changes in the binding of a fluorescent peptide to the calcium/calmodulin complex. Each system was exposed to a 20.9 microT static field superimposed on a 20.9 microT sinusoidal field over a narrow frequency range centered at 16 Hz, the cyclotron frequency of the unhydrated calcium ion. In contrast to Lednev's predictions, no significant effect of combined dc-ac magnetic fields on calcium/calmodulin interactions was indicated in either experimental system.  相似文献   

7.
It was found in open test that changing magnetic fields with 8 Hz frequency and 5 mcTl induction in daily 3 hours exposition on rats with a middle level of the mobile activity move the phase of diuresis daily rhythms and epinephrine and norepinephrine yield as well. In rats with desinchronosis provoked by hypokinesia the changing magnetic fields restore the synchronism of the studied processes.  相似文献   

8.
9.
The influence of 8 Hz frequency and 5 mcTl induction changing magnetic fields on the functional state of blood neutrophils, sympathoadrenal system and brain integrative activity in rats with low, middle and high level of mobility was investigated in open test. It was found out that changing magnetic fields provoke the stress-reaction development in rats with low mobile activity. The adaptation which develops in rats with high and middle mobile activity comes later by 5-7 days in high mobility rats.  相似文献   

10.
Effect of the constant magnetic field with up to 3.2 X 10(-4) A/m intensity on the fluorescence of papain aqueous solutions was investigated. It has been shown that depending on the magnetic field direction a reversible decrease or increase of fluorescence intensity takes place. The variation of fluorescence intensity under the influence of magnetic field is maximal under excitation at long wave ultra-violet light. The effect increases with the increase of temperature, increases linearly with the increase of magnetic field intensity but doesn't depend on protein concentration in diluted solutions. The examination of the data leads to the conclusion on the existence of two possible mechanisms: the variation of properties of surface tryptophan residues environment and paramagnetic orientation of protein globule under the influence of a magnetic field.  相似文献   

11.
12.
Ermakov  A. M.  Lednev  V. V. 《Biophysics》2010,55(4):633-636
The effects of weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+ and extremely weak alternating magnetic field on the metamorphosis of the mealworm beetle Tenebrio molitor have been studied. It was shown that the exposure of pupas of insects to all above-indicated types of fields stimulates the metamorphosis. However, after the exposure to weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+, the number of insects with anomalies increases, which is not observed by the action of the weak alternating magnetic field.  相似文献   

13.
Ermakov AM  Lednev VV 《Biofizika》2010,55(4):715-719
The effects of weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+ and extremely weak alternating magnetic field on the metamorphosis of the meal-worm beetle Tenebrio molitor have been studied. It was shown that the exposure of pupas of insects to all above-indicated types of fields stimulates the metamorphosis. However, after the exposure to weak combined magnetic fields adjusted to the parametric resonance for Ca2+ and K+, the number of insects with anomalies increases, which is not observed by the action of the weak alternating magnetic field.  相似文献   

14.
The parameters of the low-frequency (1, 4.4, 16.5 Hz or the sum of these frequencies) extremely weak (300, 100, 150–300 nT, according to frequencies) alternating component of combined magnetic fields have been found, which in combination with a weak collinear static field of 42 μT (the induction corresponds to the range of the geomagnetic field) has a marked antitumor activity. The exposure to these magnetic fields inhibits the tumor growth in mice with an intraperitoneally transplanted Ehrlich ascites carcinoma. The effect manifests itself as an increase in the life of tumor-bearing animals and in the content of damaged tumor cells. It was found that the death of tumor cells by the action of weak fields occurs predominantly by the mechanism of necrosis.  相似文献   

15.
16.
The experimental results are given concerning the effect of variable magnetic field (VMF) with the frequency of 8 Hz and intensity 4 A/m on some parameters of rat haemocoagulation system under standard mobile regime as well as under prolonged hypokinesia. It is stated that repeated daily exposition of VMF causes hypocoagulational blood shift in intact animals. Under the effect of simultaneous VMF and hypokinesia the correction of hypercoagulational shift induced by animal hypokinesia was detected. The highest VMF effect was observed in prolonged experiments. A conclusion is drawn concerning the ability of VMF with the given parameters to limit the development of rat blood hypercoagulation under hypokinesia.  相似文献   

17.
It has been shown that the ultralow‐frequency extremely weak alternating component of combined magnetic fields (MFs) exhibits a marked antitumor activity. The parameters of this component have been found (frequency 1, 4.4, 16.5 Hz or the sum of these frequencies; intensity 300, 100, 150–300 nT, respectively) at which this MF in combination with a collinear static MF of 42 µT inhibits or suppresses the growth of Ehrlich ascites carcinoma (EAC) in mice. It was shown that the exposure of mice with EAC to combined MFs causes structural changes in some organs (liver, adrenal glands), which are probably due to the total degradation of the tumor tissue. In mice with transplanted EAC, the tumor tissue after exposure to weak MFs was practically absent, as distinct from control animals in which the invasion of the tumor into the adipose tissue surrounding the kidneys, mesenteric lymph nodes, and spermatic appendages was observed. In animals without tumors, no pathological deviations from the norm in the structure of organs and tissues occurred after exposure to weak MF, indicating that this factor per se is not toxic to the organism. Bioelectromagnetics 30:343–351, 2009. © 2009 Wiley‐Liss, Inc.  相似文献   

18.
Ischemia-reperfusion injuries, such as those suffered from various types of cardiovascular disease, are major causes of death and disability. For relatively short periods of ischemia, much of the damage is potentially reversible and in fact, does not occur until the influx of oxygen during the reperfusion stage. Because of this, there is a window of opportunity to protect the ischemic tissue. Here, we review several mechanisms of protection, such as heat shock proteins, opioids, collateral blood flow, and nitric oxide induction, and the evidence indicating that magnetic fields may be used as a means of providing protection via each of these mechanisms. While there are few studies demonstrating direct protection with magnetic field therapies, there are a number of published reports indicating that electromagnetic fields may be able to influence some of the biochemical systems with protective applications.  相似文献   

19.
The effects of some components of the blood on times of spin-grade and spin-spin relaxation of water protons using the method of proton magnetic relaxation. Equations of correlation for the content of hemoglobin and proteins in saline was obtained. A model for the relaxation measurements of the whole blood was constructed.  相似文献   

20.
It was shown that permanent (B = 50 μT, horizontal plane, direction to the north) and alternating magnetic fields (North–South direction) exerted influences on seed germination as well as on cytological and biochemical features of seedlings characteristic of investigated species (Lepidium apetalum, Artemisia vulgaris, A. jacutica, and A. dracunculus) of wild plants growing in Central Yakutia. Under the effect of permanent magnetic field (MF), germinating capacity of seeds decreased (except for A. vulgaris), whereas alternating MF of different frequencies improved their germinating capacity, except for L. apetalum and A. jacutica at frequencies of 200 and 300 Hz, respectively. Under permanent MF, the rate of lipid peroxidation in the tissues of the seedlings decreased, whereas the content of low molecular weight antioxidants rose; when the plants were exposed to an alternating magnetic field, the content of MDA and peroxidase activity increased, and the content of low molecular weight antioxidants followed an ambiguous pattern.  相似文献   

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