Silvio R. De Luka

Hematological parameters' changes in mice subchronically exposed to static magnetic fields of different orientations.

Static magnetic fields (SMFs) are time independent fields whose intensity can be spatially dependent. This study investigates influence of subchronic continuous exposure to upward and downward directed SMF on hematological parameters and spleen cellularity in mice. The experiment is performed on the Northern hemisphere; consequently, the vertical component of geomagnetic field is directed downward. Male, Swiss-Webster, 6 weeks old mice were exposed to the vertically declining SMF. Mice were divided in three groups and continuously exposed or not exposed for 28 days to the SMF characterized by the averaged field of 16 mT and averaged field gradient of 10 mT/cm. Differently oriented SMF did not alter hemoglobin and hematocrit content among the groups. However, the groups exposed to the upward and downward fields had statistically significant higher levels of serum transferrin compared to the control. Moreover, spleen cellularity in animals in the downward group was significantly higher compared to the upward and control group. In addition, spleen lymphocytes in both of the exposed groups were significantly higher than in the control group. In contrast, spleen granulocytes in the exposed groups were significantly lower than in the control group. Significant decrease was also observed in brain and liver iron content with concomitant increase of iron in serum and spleen in exposed animals. Subchronic continuous exposure to 16 mT SMF caused lymphocyte and granulocyte redistribution between spleen and blood. This distribution is typical for stress induced hematological changes. These results suggest that observed changes were not due to an unspecific stress response, but that they were rather caused by specific adaptation to subchronic SMF exposure.

Subchronic exposure to static magnetic field differently affects zinc and copper content in murine organs

Abstract Purpose Static magnetic fields (SMF) have been widely used in research, medicine and industry. Since zinc and copper play an important role in biological systems, we studied the effects of the subchronic continuous SMF exposure on their distribution in murine tissues. Materials and methods For 30 days, mice were exposed to inhomogeneous, vertical, downward or upward oriented SMF of 1 mT averaged intensity with spatial gradient in vertical direction. Results SMF decreased the amount of copper and zinc in liver. In brain, zinc levels were increased and copper levels were decreased. In spleen, zinc content was reduced, while copper amount remained unchanged. Conclusions Subchronic exposure to SMF differently affected copper and zinc content in examined organs, and the changes were more pronounced for the downward oriented field. The outcome could be attributed to the protective, rather than the harmful effect of SMF.

Quantification of structural changes in acute inflammation by fractal dimension, angular second moment and correlation.

The aim of the study was to examine alteration and possible application of fractal dimension, angular second moment, and correlation for quantification of structural changes in acutely inflamed tissue.

Alpha-lipoic acid affects the oxidative stress in various brain structures in mice with methionine and choline deficiency.

Deficiency in methionine or choline can induce oxidative stress in various organs such as liver, kidney, heart, and brain. This study was to examine the effects of alpha-lipoic acid (LA) on oxidative stress induced by methionine and choline deficiency (MCD) in several brain structures. Male mice C57BL/6 (n = 28) were divided into four groups: (1) control – continuously fed with standard chow; (2) LA – fed with standard chow and receiving LA; (3) MCD2 – fed with MCD diet for two weeks, and (4) MCD2+LA – fed with MCD diet for two weeks and receiving LA (100 mg/kg/day intraperitonealy [i.p.]). Brain tissue (cortex, hypothalamus, striatum and hippocampus) was taken for determination of oxidative stress parameters. MCD diet induced a significant increase in malondialdehyde and NOx concentration in all brain regions, while LA restored their content to normal values. Similar to this, in MCD2 group, activity of total SOD, MnSOD, and Cu/ZnSOD was reduced by MCD diet, while LA treatment improved their activities in all brain structures. Besides, in MCD2 group a decrease in catalase activity in cortex and GSH content in hypothalamus was evident, while LA treatment induced an increase in catalase activity in cortex and striatum and GSH content in hypothalamus. LA treatment can significantly reduce lipid peroxidation and nitrosative stress, caused by MCD diet, in all brain regions by restoring antioxidant enzymes activities, predominantly total SOD, MnSOD, and Cu/ZnSOD, and to a lesser extent by modulating catalase activity and GSH content. LA supplementation may be used in order to prevent brain oxidative injury induced by methionine and choline deficiency.

Analytical Description of Two-Dimensional Magnetic Arrays Suitable for Biomedical Applications

Two-dimensional magnetic arrays are used to generate a magnetic field that pervades a layer of volume above the arrays surface, often creating regions of high magnetic flux density gradients. We have recently employed an array with equally oriented magnetic moments of individual elements in several biomedical experiments. We have chosen this type of array because of the slowly decreasing magnetic field it produces, which extends far from the arrays surface and permeates the experimental volume. In order to fully define experimental conditions related to the applied magnetic field, we derive exact closed-form expressions for the magnetic flux density. Based on these analytical expressions and exploiting the array periodicity, a method is proposed for the approximate assessment of the main magnetic field parameters of interest-mean magnetic flux density and mean gradient of its component perpendicular to the arrays surface. The obtained approximate assessment can further serve as a tool for the design of arrays with the desired mean field parameters. All the results are verified and validated by comparison with the finite element modeling as well as measurements.

Static magnetic field reduces blood pressure short-term variability and enhances baro-receptor reflex sensitivity in spontaneously hypertensive rats

Abstract Purpose: It has been shown that chronic exposure of young spontaneously hypertensive rats (SHR) to static magnetic field (SMF) delays the development of overt hypertension. Therefore the aim of the present work was to investigate the effects of SMF on autonomic cardiovascular control in adult spontaneously hypertensive rats. Materials and methods: Experiments were performed in freely moving spontaneously hypertensive rats equipped with femoral arterial catheter for blood pressure recording. Spontaneously hypertensive rats were exposed for 30 days to upward-oriented SMF (n = 17) or downward-oriented SMF (n = 17) of 16 mT intensity. A control group of spontaneously hypertensive rats (n = 17) was not exposed to SMF. Neurogenic cardiovascular control was evaluated by spectral analysis of arterial blood pressure and heart rate short-term variability and baro-receptor reflex sensitivity using the sequence method. Results: Exposure of spontaneously hypertensive rats to both upward- and downward-oriented SMF significantly reduced arterial blood pressure and enhanced baro-receptor reflex sensitivity. Downward-oriented SMF reduced heart rate, too. SMF of either orientation reduced systolic blood pressure variability in very low frequency domain while downward-oriented SMF also reduced low-frequency and increased high frequency domains. Conclusion: It follows that prolonged exposure to SMF is beneficial for neurogenic cardiovascular control in hypertension.

Effects of IL-33/ST2 pathway in acute inflammation on tissue damage, antioxidative parameters, magnesium concentration and cytokines profile

AIM The aim of this study was to examine the role of IL-33/ST2 pathway in a pathogenesis of acute inflammation and its effects on tissue damage, antioxidative capacity, magnesium concentration and cytokine profile in acutely inflamed tissue. MATERIAL AND METHODS Male mice were randomly divided in four groups: wild-type control group (WT-C), ST2 knockout control group (KO-C), wild-type inflammatory group (WT-I), and ST2 knockout inflammatory group (KO-I). Acute inflammation was induced in WT-I and KO-I by intramuscular injection of turpentine oil, while mice in WT-C and KO-C were treated with saline. After 12h, animals were euthanized, and blood was collected for determination of creatine kinase (CK) and aspartate transaminase (AST) activity. The treated tissue was used for histopathological analysis, determination of volume density of inflammatory infiltrate (Vdii) and necrotic fiber (Vdnf), gene expression of interleukin (IL)-33, ST2, tumor necrosis factor alpha (TNF-alpha), IL-6, IL-12p35, and transforming growth factor beta (TGF-beta), concentration of magnesium (Mg), copper (Cu), selenium (Se), manganese (Mn) and reduced glutathione (GSH), and superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity. RESULTS Presence of inflammatory infiltration and necrosis in the treated tissue was histopathologically confirmed in WT-I and KO-I. Vdii was significantly higher in WT-I when compared to KO-I, whereas Vdnf did not significantly differ between WT-I and KO-I. CK and AST significantly increased in both inflammatory groups when compared to corresponding control groups. However, the values of CK and AST were significantly higher in WT-I than in KO-I. Mg in the treated tissue was significantly lower in WT-I in comparison to WT-C and KO-I, while there was no significant difference between KO-C and KO-I. There was no significant difference in Cu, Se, and Mn in the treated tissue between WT-C, KO-C, WT-I and KO-I. Gene expression of IL-33 in the treated tissue increased in both inflammatory groups when compared to the corresponding control groups, but it was significantly higher in KO-I than in WT-I. Gene expression of ST2 in the treated tissue was significantly higher in WT-I than in WT-C. Gene expression of TNF-alpha, IL-6, and IL-12p35 in the treated tissue was significantly higher in WT-I and KO-I than in the corresponding control groups, and IL-6 was significantly higher in KO-C than in WT-C. TGF-beta gene expression in the treated tissue was significantly higher in KO-I when compared to WT-I, while there was no difference between WT-C and KO-C. SOD activity decreased at the site of acute inflammation in both inflammatory groups, while the GPx activity increased. GSH in the treated tissue was significantly higher in KO-I than in KO-C or WT-I. CONCLUSION The results of our study have indicated, to our knowledge for the first time, that IL-33/ST2 pathway plays a role in enhancing inflammation and tissue damage at the site of acute inflammation by affecting the concentration of magnesium and GSH, important for antioxidative capacity, as well as gene expression of anti-inflammatory cytokine TGF-beta.

Effects of Il-33/St2 pathway on alteration of iron and hematological parameters in acute inflammation.

AIM The aim of this study was to examine the role of the IL-33/ST2 pathway in pathogenesis of acute inflammation by investigating its possible role in alteration of iron and hematological parameters in experimental model of acute inflammation. MATERIAL AND METHODS Wild-type and ST2 knockout BALB/c mice were divided into four groups: wild-type control group, ST2-/- control group, wild-type inflammatory group, and ST2-/- inflammatory group. Acute inflammation was induced by intramuscular injection of turpentine oil, while control groups were injected with saline. After 12h animals were anesthetized, and the treated tissue, blood and spleen were collected. Iron concentration in the treated tissue, hemoglobin blood concentration, mean corpuscular hemoglobin (MCH), hematocrit, erythrocyte, neutrophil and lymphocyte blood count, and erythrocytes percentage in spleen were determined. RESULTS Iron concentration in the treated tissue was significantly higher in wild-type inflammatory group (WT-I) when compared to both, the wild-type control group (WT-C) and ST2-/- inflammatory group (KO-I). There was no significant difference in iron concentration between ST2-/- control group (KO-C) and the KO-I. MCH had significantly decreased in WT-I when compared to WT-C, while there was no significant difference between KO-C and KO-I. Hemoglobin blood concentration significantly increased in KO-I in comparison to KO-C, while it did not significantly differ between WT-I and KO-I. Erythrocyte count and hematocrit had significantly increased, while the percentage of erythrocytes in spleen decreased in both inflammatory groups when compared to their controls. Neutrophil count significantly decreased in WT-I, when compared to WT-C. Lymphocyte count decreased in both inflammatory groups when compared to their controls. CONCLUSION Results of this study indicate that the IL-33/ST2 axis could have a role in the alteration of iron in acute inflammation, namely in an increase of iron concentration at the site of acute inflammation and a decrease of blood mean corpuscular hemoglobin.

Modulation of rat synaptosomal ATPases and acetylcholinesterase activities induced by chronic exposure to the static magnetic field

Abstract Purpose: It is considered that exposure to static magnetic fields (SMF) may have both detrimental and therapeutic effect, but the mechanism of SMF influence on the living organisms is not well understood. Since the adenosine triphosphatases (ATPases) and acetylcholinesterase (AChE) are involved in both physiological and pathological processes, the modulation of Na+/K+-ATPase, ecto-ATPases and AChE activities, as well as oxidative stress responses were followed in synaptosomes isolated from rats after chronic exposure toward differently oriented SMF. Material and methods: Wistar albino rats were randomly divided into three experimental groups (six animals per group): Up and Down group - exposed to upward and downward oriented SMF, respectively, and Control group. After 50 days, the rats were sacrificed, and synaptosomes were isolated from the whole rat brain and used for testing the enzyme activities and oxidative stress parameters. Results: Chronic exposure to 1 mT SMF significantly increased ATPases, AChE activities, and malondialdehyde (MDA) level in both exposed groups, compared to control values. The significant decrease in synaptosomal catalase activity (1.48 ± 0.17 U/mg protein) induced by exposure to the downward oriented field, compared to those obtained for Control group (2.60 ± 0.29 U/mg protein), and Up group (2.72 ± 0.21 U/mg protein). Conclusions: It could be concluded that chronic exposure to differently oriented SMF increases ATPases and AChE activities in rat synaptosomes. Since brain ATPases and AChE have important roles in the pathogenesis of several neurological diseases, SMF influence on the activity of these enzymes may have potential therapeutic importance

Design and Optimization of Electromagnets for Biomedical Experiments With Static Magnetic and ELF Electromagnetic Fields

With the expanding usage of various devices, which emit static and extremely low-frequency magnetic fields, increases the number of biomedical reports on their influence as well as demand for suitable experimental exposure systems. Experimental setups range from permanent magnets through Helmholtz coils to solenoids; however, almost all of them provide relatively weak magnetic fields of up to 10 mT. Widespread use of devices such as MR scanners imposes intentional as well as unintentional exposure to stronger fields. A typical solenoid produces stronger although less homogeneous field than the most commonly used experimental equipment composed of sets of coaxial coils. In order to provide scalable, relatively strong, low-varying field within experimental volume that is large enough for in vivo as well as in vitro experiments modified solenoids are considered. Variation of the field was reduced by modifying the shape and size of solenoids cross section. Modified solenoids were modeled analytically, numerically, and as a prototype. Solenoid geometries were optimized for maximal field performance and minimal power consumption. The optimal modified solenoids scalable to desired sizes of the experimental volume and values of maximal magnetic induction intensities are offered. The suggested solenoid modification method can decrease field variation as much as 10.6 times.