Correction of lipid metabolism in rats with limited mobility by an alternating magnetic field of infra-low frequency

The effect of changing magnetic field at the frequency of 8 Hz and intensity at 4.1 A/M on rats lipid metabolism state in the exposition of continuous hypokinesia was investigated. It was found that changing magnetic field of such parameters greatly restricted the development of hyperlipidemia of rats with a low level of mobile activity.     

Effect of alternating magnetic field on the composition and level of lipids in radish seedlings

The effects of alternating magnetic field (AMF) with the frequency of 50 Hz on the dynamics of unfolding of cotyledon leaves, the composition and level of polar and neutral lipids and their component fatty acids (FA) were studied in 5-day-old radish seedlings (Raphanus sativus L. var. radicula D.L., cv. Rozovo-krasnyi s belym konchikom) grown in the light and in the dark. AMF weakened the inhibitory effect of light on unfolding of cotyledon leaves. In the light, the total content of lipids, as well as the level of polar and neutral lipids, in the seedlings in AMF was greater than in control material. In polar lipids, the total amount of glyco-and phospholipids increased; in neutral lipids, the level of triacylglycerols rose. The ratio between phospholipids and sterols (PhL/S) increased. In the dark, the total content of lipids and the level of neutral lipids in the seedlings in AMF were lower than in control material, and the ratio PhL/S decreased. In control material, there were no differences in the relative total content of unsaturated FA in the light and in the dark, whereas the level of linolenic acid was higher in the light than in the dark. AMF induced a decrease in the content of linolenic acid in the light and a rise in the dark; the level of erucic acid in the light decreased. The ratio between unsaturated and saturated FA decreased both in the light and in the dark. It was concluded that AMF with the frequency of 50 Hz was an adjusting agent considerably changing the content of lipids in the radish seedlings in the light and in the dark.     

Effect of lipid composition on rat liver nuclear membrane fluidity

Nuclear membrane fluidity is measured in rat liver by use of the fluorescence anisotropy of two probes: diphenylhexatriene and its cationic derivative trimethylammonium-diphenylhexatriene. It has been shown that, in 2-month-old rat liver cells, the bilayer surface is less fluid than the hydrophobic core. The fluidity was higher in 6-day-old rat liver nuclei, in which both the amount of cholesterol and the cholesterol/phospholipid ratio decreased. The influence of the single phospholipids, and in particular of phosphatidylcholine, has been studied by increasing the phosphatidylcholine with a choline base exchange reaction in isolated nuclear membranes. After this reaction, the fluorescence anisotropy of the bilayer surface increased, whereas at the hydrophobic core it decreased. Analysis of fatty acid composition shows an increase of phosphatidylcholine unsaturated fatty acids. The results show that the fluidity of nuclear membranes changes in relation to the lipid content and to the fatty acid composition. The role of nuclear membrane fluidity in cell function is discussed. © 1997 John Wiley & Sons, Ltd.     

Effect of an alternating magnetic field on the development of spontaneous hypertension in rats

The effect of varying magnetic field on the development of spontaneous hypertension was studied in experiments on Okamoto rats. The influence of magnetic field during antenatal development caused persistent changes in lymphocyte and organ metabolism and accelerated the appearance of spontaneous hypertension in rats. Based on enzymatic activity of lymphocytes it is possible to predict the development of spontaneous arterial hypertension.     

Effect of a low-frequency alternating magnetic field on the formation of avoidance reflexes in the rat

Alternating magnetic field with induction of 3 mTl, frequency of 10 Hz, homogenous, with impulses of sinusoidal form and a vector with horizontal direction, produces an inhibitory effect on the formation of avoidance reflexes in white rats. The after-effect of the field lasts less than 1 hour.     

Conditioned reflex activity of pigeons as affected by an infra-low frequency alternating magnetic field

In experiments on 35 pigeons formation and realization was studied of alimentary motor conditioned reflexes under the influence of alternating magnetic field (AMF) with a frequency of 5 and 8 Hz and induction 5100 nTl. It has been found that under the action of such AMF, the percent of adequate responses lowers and the time of motor reaction during execution of motor alimentary conditioned reflexes and of delayed reactions increases. Realization of delayed reactions is disturbed more significantly than that of the present conditioned reflexes. AMF with a frequency of 8 Hz influences more expressively the pigeons conditioned activity in comparison with 5 Hz frequency.     

The effect of alternating electric field of industrial frequency on testicles of white mice]

Under the chronic influence of the alternating electric field (intensity 40 kV/m, frequency 50 Hz) the oppression of spermatogenesis was observed in the ontogenesis process of testicles of white mice. It was a result of disturbances in spermatogonia and spermatids. Investigation of the stability of mice testicles in different age groups (juvenile, puberal and old) has shown that the 1st and the 3d groups are the most sensitive ones.     

Effect of N-stearoylethanolamine on the lipid peroxidation process and lipid composition of the rat liver in acute morphine intoxication

The effect of N-stearoylethanolamine (NSE) on the lipid peroxidation process, antioxidant enzymes activity, phospholipid and fatty acid content in the rat liver tissues under acute morphine administration was studied. It was shown that morphine administration (30 mg/kg of body weight) caused an increase of the amount of thiobarbituric acid reactive substances (TBARS), alteration of antioxidant enzymes activity, decrease the protein level, quantity of total lipids and phospholipids, phosphatidylcholine, cholesterol esters; altered the content of some individual fatty acids. NSE administration (50 mg/kg of body weight) promoted normalization of the antioxidant enzymes activity and prevented the TBARS accumulation and decreased the total lipid and phospholipid quantity, increased the content of free and total cholesterol, corrected the level of free and individual fatty acids. It was assumed that NSE possessed antioxidative, membranoprotective and adaptive properties.     

Influence of an alternating magnetic field on the bactericidal effect of ionizing radiation

A study was made of the effect of alternating magnetic field (AMF) and ionizing radiation delivered separately or in a combination on the microorganisms differing in radio-resistance. AMF (240 and 750 E) had no pronounced bactericidal action. A synergistic increase in the sterilizing effect of ionizing radiation was demonstrated after incubation of irradiated bacteria in AMF. The radiation-magnetic technique is proposed for sterilization of preparations and articles made of non-thermoresistant materials which permits to decrease by 1.5 times the bactericidal dose of ionizing radiation.     

Effect of power frequency harmonics on magnetic field measurements

This paper presents a study of the effect of harmonic frequencies on magnetic field measurements. We introduced magnetic field meters in a known magnetic field of different frequencies: power frequency (50 Hz) as well as 3rd (150 Hz) and 5th (250 Hz) harmonic frequencies. Two magnetic field levels (0.25 A and 2.5 A) were used. A Helmholtz coil was applied to generate an exact magnetic field. The difference between the measurement results at harmonic frequencies and at power frequency was analyzed using the t-test for matched pairs. The test results show significant differences (P≤0.01) for 13 out of 28 tests carried out, which is probably due to a curved frequency response near the power frequency. It is, therefore, essential to consider harmonic frequencies in magnetic field measurements in practice. Received: 12 January 1998 / Accepted in revised form: 1 October 1999     

Effect of aging on the activity of the phosphate carrier and on the lipid composition in rat liver mitochondria

The effect of aging on the activity of the phosphate carrier and on the lipid composition in rat liver mitochondria has been investigated. It was found that the rate of phosphate transport in mitochondria from aged rats (28 months old) is significantly reduced (around 40%) compared to that obtained in mitochondria from young control rats (5 months old). Kinetic analysis of the phosphate transport indicates that only the Vmax of this process is affected, while there is no change in the Km values. The lower activity of the phosphate carrier in mitochondria from aged rats is also documented by swelling experiments. The age-related decrement in the activity of the phosphate carrier was found not to be due neither to a change in the endogenous content of phosphate nor to a change in the transmembrane delta pH value. Inhibitor titrations with mersalyl provide no evidence for a lower content of functional phosphate translocase in mitochondria from aged rats. There is no difference either in the respiratory control ratios or in the ADP/O ratios between mitochondria from young and aged animals. The hepatic mitochondrial lipid composition is altered significantly in aged rats: the total cholesterol increases (31%), the phospholipids decrease (12%), and the cholesterol/phospholipid molar ratio increases (44%). Among the phospholipids cardiolipin shows the greatest alteration (30% decrease with age). Alterations were also found in the pattern of fatty acids. The age-related decrement in the activity of the phosphate carrier appears to be dependent on changes in the lipid domain surrounding the carrier protein molecule in the mitochondrial membrane.     

Effect of diet on the lipid composition of cell nuclei and liver mitochondria during ontogenesis of the rat

The possible influence of the type of dietary fat on quantitative changes of different lipids in microsomes, nuclei and chromatin in hepatic cells of albino rats in ontogenesis was studied. While the type of diet had no significant influence on the levels of different phospholipids and fatty acids of nuclei, the type of dietary fat exerted definite effect on the levels of whole phospholipids, cholesterol of microsomes, nuclei and fatty acids of chromatin. The age specificity was observed in nuclear structures.     

Effect of a permanent magnetic field on the formation of lipid bilayers

Effect of the constant magnetic field (MF) by the induction of 1.1 T on formation kinetics of bilayer lipid membranes (BLM) from egg lecithin in decane was discovered. Under the effect of MF oriented in parallel to the lipid film place the rate of BLM formation decreases, while at its perpendicular orientation it is accelerated. The stationary value of BLM capacity decreases under MF effect at both orientations. The discovered changes in the rate of BLM formation under MF effect seem to be related to the effect of MF on liquid crystalline structure of colour lipid film.     

Effect of copper deficiency and Sodium intake upon liver lipid and mineral composition in the rat

The effect of copper and sodium intake upon liver cholesterol concentrations, fatty acid profile, and mineral concentrations were studied in the Long-Evans rat. Forty-eight male weaning rats were divided into three groups of 16 each and fed a semipurified diet containing either 0, 3, or 8 mg of added copper/kg of diet. At 100 d of age, half of the animals in each group were given 1% NaCl as drinking water and the other half was given deionized-distilled water for 12 wk. Copper deficiency in rats produced elevations in liver palmitate and oleate concentrations, but decreases in linoleate concentrations. The ratio of oleate:stearate was higher in copper deficient rats. Liver copper levels were decreased, but liver iron concentrations were elevated in copper deficient rats. Sodium intake did not have an effect on any of the parameters studied. These results suggested that dietary copper deficiency alters both liver mineral and fatty acid composition.     

Enzymac characterization and lipid composition of rat liver subcellular membranes

1.

1. Mitochondria, inner and outer mitochondrial membranes, microsomes, smooth and rough endoplasmic reticulum membranes and plasma membranes were isolated from rat liver.     

Effect of changes in the membrane lipid composition on the activity of respiratory chain enzymes in rat liver mitochondria

The lipid composition and fatty acid spectrum of individual phospholipid fractions of internal and external membranes of mitochondria was studied in alloxan diabetes. It was found that the phosphatidylserine content is reduced under these conditions, while those of lysophosphatidylcholines, diphosphatidylglycerols and cholesterol are increased, and the fatty acids are saturated with phospholipids. The observed changes in the lipid composition of membranes cause a decrease in the rate of oxygen consumption in various metabolic states as well as in the activity of NAD X H+-, succinate and cytochrome oxidases in rat liver mitochondria.     

Effect of alternating the magnetic field on phosphate metabolism in the nervous system of Helix pomatia

The effect of extremely low frequency magnetic fields (50 Hz, 0.5 mT) - ELF-MF, on phosphate metabolism has been studied in the isolated ganglions of the garden snail Helix pomatia, after 7 and 16 days of snail exposure to ELF-MF. The influence of ELF-MF on the level of phosphate compounds and intracellular pH was monitored by 31P NMR spectroscopy. Furthermore, the activity of enzymes involved in phosphate turnover, total ATPases, Na+/K+-ATPase and acid phosphatase has been measured. The exposure of snails to the ELF-MF for the period of 7 days shifted intracellular pH toward more alkaline conditions, and increased the activity of investigated enzymes. Prolonged exposure to the ELF-MF for the period of 16 days caused a decrease of PCr and ATP levels and decreased enzyme activity, compared to the 7-day treatment group. Our results can be explained in terms of: 1. increase in phosphate turnover by exposure to the ELF-MF for the period of 7 days, and 2. adaptation of phosphate metabolism in the nervous system of snails to prolonged ELF-MF exposure.