Distribution of erythrocyte in a model vessel exposed to inhomogeneous magnetic fields

In order to investigate magnetic field effects on blood flow, changes in the flow of erythrocytes in a model branched vessel were observed in an inhomogeneous magnetic field. The magnetic field was applied perpendicular to the straight vessel before branching. When the suspension containing paramagnetic erythrocytes with high spin methemoglobin or deoxygenated hemoglobin flowed in the model vessel, the erythrocytes were attracted towards the stronger magnetic field (i.e. to the side branch) and an excess flow of erythrocytes to the side branch was detected. This excess flow of erythrocytes to the side branch was the highest at a hematocrit of about 5% for the suspension containing erythrocytes with high spin methemoglobin. In the case of mixed suspensions containing erythrocytes with high spin methemoglobin and oxygenated erythrocytes, the excess flow of erythrocytes to the side branch reached its maximum at the "partial hematocrit" for the paramagnetic erythrocyte of around 5% and remained nearly constant with a further increase of the "partial hematocrit." The effect of magnetic field decreased as the flow velocity increased. These results are explained with the paramagnetism of erythrocytes and with the assumption of a hydrodynamic interaction among erythrocytes which are pulled in the direction of the magnetic field. It is suggested that a strong inhomogeneous magnetic field is not totally negligible to the blood circulation.     

Modulation of the intensity of fluorescence of aqueous solutions of proteins by magnetic field

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.     

The effect of weak magnetic fields on the production of reactive oxygen species in neutrophils

It was shown that a 1-h-long exposure of mouse peritoneal neutrophils to a combination of a weak constant magnetic field (42 μT) and low-frequency alternating magnetic fields collinear to the weak constant magnetic field (the sum of the frequencies 1.0, 4.4, and 16.5 Hz; amplitude, 0.86 μT) at physiological temperatures caused an increase in the intracellular production of reactive oxygen species, as measured by the changes in fluorescence of the products of 2,7-dichlorodihydrofluorescein and dihydrorhodamine 123 oxidation. The effect of weak magnetic fields was significantly more pronounced in the presence of low concentrations of respiratory burst activators (N-formyl-Met–Leu–Phe or phorbol 12-meristate-13-acetate).

     

Functional brain mapping by blood oxygenation level-dependent contrast magnetic resonance imaging. A comparison of signal characteristics with a biophysical model.

It recently has been demonstrated that magnetic resonance imaging can be used to map changes in brain hemodynamics produced by human mental operations. One method under development relies on blood oxygenation level-dependent (BOLD) contrast: a change in the signal strength of brain water protons produced by the paramagnetic effects of venous blood deoxyhemoglobin. Here we discuss the basic quantitative features of the observed BOLD-based signal changes, including the signal amplitude and its magnetic field dependence and dynamic effects such as a pronounced oscillatory pattern that is induced in the signal from primary visual cortex during photic stimulation experiments. The observed features are compared with the results of Monte Carlo simulations of water proton intravoxel phase dispersion produced by local field gradients generated by paramagnetic deoxyhemoglobin in nearby venous blood vessels. The simulations suggest that the effect of water molecule diffusion is strong for the case of blood capillaries, but, for larger venous blood vessels, water diffusion is not an important determinant of deoxyhemoglobin-induced signal dephasing. We provide an expression for the apparent in-plane relaxation rate constant (R2*) in terms of the main magnetic field strength, the degree of the oxygenation of the venous blood, the venous blood volume fraction in the tissue, and the size of the blood vessel.     

The influence of ultrasound and constant magnetic field on gametes, zygotes, and embryos of the sea urchin

The influence of constant magnetic field, power 7 T, and ultrasound, frequency 2, 4 and 8 MHz, on gametes, fertization, embryos and larvae of the sea urchin was studied. It was shown that magnetic field breaks the process of the gamete fusion but does not influence gametes, embryos, and larvae. Ultrasound impairs the motility of spermatozoa and larvae, prevents the fertilization, and breaks the embryonic development. It is assumed that the effect of the magnetic field is connected with the response of the cortical cytoskeleton, which consists of bundles of actin microfilaments. The rearrangement of the cortical cytoskeleton occurs during the first 20 minutes after the contact of sperm with the egg. Also there is effect of magnetic fields on calcium ions, which are liberated during the first seconds after gamete contact. The effect of the ultrasound is explained by a small increase in water temperature and cavitation process, which break celluar structures.     

A study of specific electrical conductivity of water by the action of constant magnetic field, electromagnetic field, and low-frequency mechanical vibrations

The effect of a constant magnetic field, an electromagnetic field, and low-frequency mechanical vibrations on specific electrical conductivity of distilled water was studied. Newly formed (fresh), three-day- and six-day-old distilled water was used. The exposure of distilled water to a constant magnetic field (2.5 mT), electromagnetic field (2.5 mT and 1-100 Hz), low-intensity mechanical vibrations (1-100 Hz) with an intensity of 30 Db led to a reduction of its specific electrical conductivity. It was found that, as water aged, the effect of these factors on the specific electrical conductivity decreased.     

Fibrinolytical processes in rabbits activated by the magnetic field

Rabbits were exposed to a constant magnetic field of 0.005 T, 0.1 T and 0.3 T induction for one hour per day each day for a period of four weeks. It was found that the magnetic field increases the rate of fibrinolytical processes. A decrease in fibrinogen concentration, an increase in the level of fibrinogen degradation products and a considerably shorter time of fibrinolysis in plasma were all noted. The magnitude of these processes was proportional to duration of exposure to the magnetic field in action. These date confirms the similar effect observed in other mammalians (guinea pigs, rats). Thus, the application of a static magnetic field of intensity as low as 0.005 T to increase a fibrinolytical processes in the thrombotic therapy seems to be justified.     

Assessment of hemapoietic system reaction of mice when exposed to pulsed magnetic field

The focus of the study was on the reaction of by the haemopoietic system of mice subjected to impulse magnetic field. The source of the impulse magnetic field was the Shakhparonov's generator. The animals used in the experiments were mice of two strains--CBA, C57B1/6 and white non-inbred mice. These animals were exposed to impulse magnetic field during 1, 3 and 7 days. Animals were examined twice: immediately after the termination of exposure and 24 h later. The following effects were observed in the course of the experiments: an increase in the number of bone marrow cells right after the exposure termination; an increase in the number of proliferation pool cells with the increase in their mitotic activity; 1 day after the exposure termination the number of bone marrow cells was restored to the initial values, or even it decreased; the above listed bone marrow changes led to the increase in the number of peripheral blood leucocytes in 1 day after the termination of exposure. The increase of leukocyte counts was not accompanied with changes in peripheral blood cell composition. It was suggested that exposure to impulse magnetic field increases the rates of cell cycle, the cell differentiation and the maturation.     

The in vitro Effect of a Magnetic Field on the Oxygen-Transport Function and the Gaseous Transmitter System in Blood

The effect of an alternating magnetic field with a magnetic flux density of 150 mT on the blood oxygen-transport function was studied. In vitro exposure of blood cells was performed following a 10-day series of in vivo exposure of the rat tail artery in combination with administration of chemical compounds that affect the formation of gaseous transmitters. In vitro exposure to a magnetic field changed the oxygen-transport function of the blood, as observed by a greater decrease in the affinity of hemoglobin for oxygen and an increase in the concentration of gaseous transmitters (nitric oxide and hydrogen sulfide). In animals to which nitroglycerin and sodium hydrosulfide were administered exposure to a magnetic field caused a shift in the oxyhemoglobin dissociation curve to the right; this effect was absent when a nonselective inhibitor of the NO synthase enzyme or an irreversible inhibitor of the cystathionine γ-lyase enzyme was added. These results suggest that the magnetic field affects the oxygen-binding properties of the blood by modifying intra-erythrocyte mechanisms that involve gaseous transmitters.     

外磁场对小麦萌发期过氧化物酶合成的影响及其激活效应

外磁场处理小麦种子可以提高萌发期过氧化物酶(POD)的活性;电泳图谱中,磁场透发出两条(POD)同工酶新带。在萌发初期(12h),亚胺环己酮(CHM)对外磁场提高POD活性的作用影响很小,外磁场可使POD酶蛋白的比活力增长,表明在萌发初期,磁场对种胚内的POD可能具有活化作用。萌发1d后,CHM逐渐削弱外磁场对POD活性的提高作用,而放线菌素D(AMD)则无影响。     

Hydrolysis of various peptides and proteins in weak permanent and low frequency fluctuating magnetic fields

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).     

Alterations in the rat electrocardiogram induced by stationary magnetic fields

A field strength dependent increase in the amplitude of the T-wave signal in the rat electrocardiogram (ECG) was observed during exposure to homogeneous, stationary magnetic fields. For 24 adult Sprague-Dawley and Buffalo rats of both sexes, the T-wave amplitude was found to increase by an average of 408% in a 2.0 Tesla (1 Tesla = 10⁴ Gauss) field. No significant magnetically induced changes were observed in other components of the ECG record, including the P wave and the QRS complex. The minimum field level at which augmentation of the T wave could be detected was 0.3 Tesla. The magnetically induced increase in T-wave amplitude occurred instantaneously, and was immediately reversible after exposure to fields as high as 2.0 Tesla. No abnormalities in any component of the ECG record, including the T wave, were noted during a period of 3 weeks following cessation of a continuous 5-h exposure of rats to a 1.5-Tesla field. The heart rate and breathing rate of adult rats were not altered during, or subsequent to, application of fields up to 2.0 Tesla. The effect of animal orientation within the field was tested using juvenile rats 3–14 days old. The maximum increase in T-wave amplitude was observed when subjects were placed with the long axis of the body perpendicular to the lines of magnetic induction. These experimental observations, as well as theoretical considerations, suggest that augmentation of the signal amplitude in the T-wave segment of the ECG may result from a superimposed electrical potential generated by aortic blood flow in the presence of a stationary magnetic field.     

Effect of weak combined low frequency constant and alternative magnetic fields on intrinsic fluorescence of proteins in aqueous solutions]

It was shown that weak combined static (42 microT) and low-frequency variable (40 nT; 3-5 Hz) magnetic fields change the intensity of intrinsic fluorescence of some proteins (cytochrome c, bovine serum albumin, horseradish peroxidase, alkaline phosphatase). The effect can be interpreted as a change in the conformational state of the protein in water environment by the action of weak magnetic fields. The dynamics of the process, the concentration dependence, the binding of proteins to the fluorescence probe 1,8-ANS after treatment with magnetic fields, the frequency dependence of these reactions, and the dependence of the effect on the presence of the static constituent of the magnetic field were studied. It was shown that the changes in the intrinsic fluorescence of some enzymes (horseradish peroxidase, alkaline phosphatase) are related to changes in their functional activity. It was found that the effect is partially transferred via a solvent (water, 0.01 M NaCl) preliminarily treated with magnetic field. In the solvent, changes in its intrinsic fluorescence by the action of weak magnetic fields were also registered.     

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.     

Oxidative Damage to DNA under the Action of an Alternating Magnetic Field

The content of damaged 8-hydroxy-2-deoxyguanosine nitrogenous bases in the blood DNA of healthy donors and patients with epidermolysis bullosa after exposure to an alternating magnetic field of 550 ± 30 A/m in the frequency range from 3 to 60 Hz in vitro was determined using an enzyme immunoassay. The degree of oxidative DNA damage in epidermolysis bullosa was almost twice as high as in healthy donors. It was shown that there was a significant increase in the level of 8-oxoguanine in the DNA of both groups after the magnetic field treatment, which depended in a complex way on the frequency. The resulting effect is explained by the generation of reactive oxygen species under the influence of a magnetic field and the disruption of DNA repair processes.

     

Effect of various physical factors on oscillations of light-dispersion in water and aqueous biopolymer solutions

Study of the dependence of light scattering fluctuation on temperature, mechanic perturbation and magnetic field in water and water hemoglobin and DNA solution has shown that an increase in temperature results in the decline of long-term fluctuation amplitude and in the increase of short-term fluctuation amplitude. Mechanical mixing removes long-term fluctuations and over 10 hours are spent for their recovery. Regular fluctuations appear when the constant magnetic field above 240 A/m is applied; the fluctuations are retained for many hours after the removal of the field (when the field is off). It was supposed that maintenance of long-range correlation of molecular rotation-translation fluctuation by the effect of long-range forces and external fields underlies the mechanism of long-term light scattering fluctuations.     

The hemathological reactions in rats after partial screening from natural electromagnetic fields

The influence of partial screening of EMF on the composition of white blood cells was studied in the experiments on rats. Two kinds of copper rings were used in these experiments: individual for each rat and common for the cage. It was shown that inside the ring the composition of blood cells was changed--in 3-5 hours the number of granulocytes increased and in 24 hours it restored to the initial level. The effect was more expressive in the experiments using individual rings. In control groups the experiment with plastic rings didn't reveal this effect. It was presumed that EMF prevented the decay of granulocytes. It leads to the increase of their guantity. It was revealed that there was a positive correlation between Ki-indexes of geomagnetic field (GMF) in 1-2 days before the experiments and the number of granulocytes in rats during 1995-2002. Ki-indexes reflect the degree of GMF disturbance. During magnetic storms the spreading of EMF in radio-frequency range changes. It was presumed that the effect of partial screening of EMF of rats and the activity of magnetic storms are similar in their influence on the composition of white blood cells of rats.     

Thermodynamic properties of bulk knitted structures

The mechanism of interaction of an external magnetic field with liquid was proposed. The statistical integral and configurational contributions for a free energy, entropy and specific heat for the soliton model of bulk knitted structures in a magnetic field were calculated. It was shown that the concentration of solitons depends on the effect of external fields. In the specific case of bulk knitted structures (liquid water without magnetic field), the theoretical data are consistent with experimental. The memory effects in systems with hydrogen bonds in magnetic field was explained in the framework of the continuum soliton concept.     

The process of myelopoiesis in guinea pigs under conditions of a static magnetic field

Myelopoiesis and distribution of white blood cells in peripheral blood in 210 guinea pigs related to the duration and induction of an applied magnetic field were studied. Exposure to a static magnetic field of induction 0.05 T and 0.3 T each day for 7 weeks at 1 h per day led to a decrease of basophilic and polychromatophilic erythroblasts, an increase in the percentage of cells of the granulopoietic (neutrophilic myelocytes, eosinophilic metamyelocytes, band neutrophils, band basophils, segmented eosinophils) and lymphopoietic system, a slight increase in plasma cells and decrease in the percentage of megakaryocytes in bone-marrow. In the peripheral blood the percentage of lymphocytes was increased. The observed changes were independent on the duration of magnetic field action within the magnetic induction value.     

Magnetic field influence on electrical properties of human blood measured by impedance spectroscopy

The impedance spectroscopy technique (IST) was used for studying the effect of a 0.5 T magnetic field on the electrical properties of whole human blood. A Solartron SI 1260 spectrometer was used to measure the impedance spectra of magnetic field exposed blood samples compared to non-exposed samples. An equivalent electrical circuit model, consisting in a resistance Rs in series with a parallel circuit formed by a constant phase element (CPE) and another resistance Rp, is proposed to fit the data in both cases. The experiment used 3 ml human blood samples from 160 healthy donors. A Wilcoxon matched pairs statistical test was applied to the data. The data analysis seems to show a statistically significant increase of the values of resistance Rp (Z = 5.06, P < 0.001) and capacitance CT (Z = 3.32, P < 0.001) of the blood exposed to magnetic field, by approximately 10.4% and 1.9%, respectively.