Research on sinusoidal alternating magnetic field therapy system based on inverter technology / 医疗卫生装备

Objective To develop a sinusoidal alternating magnetic field therapy system in order to overcome the disadvantages of the single output frequency and the low effective value of the output magnetic field strength of the alternating magnetic field therapy system in the market,of which the frequency and magnetic density both were continuously adjustable. Methods Multi winding Helmholtz coil was used as the magnetic field generator.On the basis of inverter technology,bipolar equivalent area method considering dead zone and variable speed integral incremental PID control algorithm were used to achieve the accuracy control of magnetic frequency and density in the coil.The accuracy of the resulting waveform and the accuracy of the magnetic field strength was verified by simulation calculation and system current and magnetic field strength test.Results The magnetic field treatment system gained high performance,total harmonic distortion (THD)of sine wave met the requirements of international standards.The obtained magnetic density was as expected of the simulation and calculation. Conclusion The device provides continuously adjustable magnetic field,which has a positive effect on the research for the medical staff, and technical references are provided to the research of magnetic field therapy system.

Effect of high-intensity alternating magnetic field on viscosity of sheep blood / 中南大学学报(医学版)

Objective:To explore the changes of blood viscosity in high-intensity alternating magnetic field and the mechanisms.Methods:Five adult sheep were randomly selected and the blood samples were placed in highintensity alternating magnetic field.Before and after exposure,the blood samples were taken and divided into 2 groups:a control group and a magnetic field group.The blood rheology and transmission electron microscopy (TEM) were performed.Results:Compared to the control group,the high shear viscosity of whole blood was decreased in the magnetic field group (P＜0.05);the whole blood low shear viscosity and plasma viscosity were also decreased (both P＜0.01).TEM showed the changes in red blood cell morphology and the double concave disc curvature.The radian of double concave disc and cell volume in the magnetic field group was larger than those in the control group.Conclusion:The high intensity alternating magnetic field may affect the distribution of surface charge and molecular current in blood cells,which in turn decrease the aggregation of cells and the blood viscosity.

Systhesis of magnetic thermosensitive hydrogel and its heat effect under alternating magnetic field / 中国药学杂志

OBJECTIVE: To synthesize magnetic thermosensitive hydrogel and study its heat effect under alternating magnetic field in vitro. METHODS: PLGA-PEG-PLGA triblock copolymer was synthesized by ring-opening polymerization of D, L-lactide and glycolide with PEG1500 in the presence of stannous iso caprylate. Magnetic thermosensitive hydrogel of different concentrations were prepared using different currents. The influences of the concentration of magnetic fluid and current of magnetic field on the heat effect were separately observed. RESULTS: The synthetized PLGA-PEG-PLGA triblock copolymer was excellently temperature sensitive. It retained the thermo-sensitivity of original hydrogel when the magnetic fluid was loaded. The 5, 10 and 20 min heating ability of magnetic fluid was positively linearly correlated with its concentration (r=0.9985, 0.9893 and 0.9711, respectively, n=3) and current of magnetic field (r=0.9948, 0.9977 and 0.9994, respectively, n=4). CONCLUSION: The magnetic thermosensitive hydrogel has excellent temperature sensitivity. When alternating magnetic field is applied, the temperature of the system can rise and reach above LCST of hydrogel. The temperature can be controlled by changing the concentration of magnetic fluid and the current of magnetic field. Copyright 2012 by the Chinese Pharmaceutical Association.

The effect of Fe3O4 nanometer magnetic fluid induced hyperthermia on implanted liver cancer in nude mice / 中华普通外科杂志

Objective To study the therapeutic effect of Fe3O4 nanometer magnetic fluid-induced hyperthermia on implanted liver cancer in nude mice under alternating magnetic field. Methods Nude mice model bearing implanted HepG2 was established. Mice were then randomly divided into 3 groups: the blank control group; the magnetic field group; nanometer magnetic fluid group. The magnetic field group were just put under the magnetic field; Nanometer magnetic fluid group received injection of PEG-PEI/Fe3O4 nanometer magnetic fluid under the alternating magnetic field. At the frequency of 40 kHz, and magnetic field of 5 kA/m, 15 minutes one day in the next 14 days. On the 7th day and the 15th day, the changes of tumor volume and weight were recorded, cell apoptosis were observed and recorded and pathological examination was done. Results On the 7th and the 15th day, in the nanometer magnetic fluid group, tumors' volume was smaller and the weight was lighter than other groups, and the tumor inhibitory rate of 54. 20% (t = 14. 506,P ＜0. 01 ) was significantly higher than the control group and the magnetic field group 22. 66% ( t = 7.497, P ＜ 0. 05 ). In the control group, tumor cells grew well, high density, the nucleus engrained, the shape irregular, the nuclear fission clear; compared with the control group, in the magnetic field group, tumor cells scatter thinly, intercellular substance increases, and necrosis area formed;in the nanometer magnetic fluid group, many of tumor cells died, their cell nucleus broke up and vanished,the blood vessel reduced obviously, and the tumor cell spread thinly. Conclusions Under the alternating magnetic field, PEG-PEI/Fe3O4 nanometer magnetic fluid inhibits liver cancer growth in nude mice model of HepG2.

Effects of Electromagnetic Fields of Different Intensity on Human Squamous Tongue Cancer Cells / 医学研究杂志

Objective To study the effects of alternating magnetic field with different intensities on the proliferation of human squa-mous tongue cancer cells in vitro. Methods Viable cells with the OD value cell and flow cytometry were revealed through MTT assay to evaluate the proliferation and apeptosis and cell cycle respectively after the cells were exposed to electromagnetic fields of different intensity (5mT,8mT,11mT) once per day lasting 1 hour for 3 days. The sham -exposure controls were correspondingly established. Results We compared the electromagnetic field groups with the normal groups by MTT assay after 24,48,72 hours. By analyzing the data in SPSS sta-tistical software , we found that the OD value of electromagnetic field groups was significantly less than that of the control groups (P <0.01) . The rates of apoptosis cells by flow cytometry revealed that EMF groups had no change as compared with control groups. But the cell cycle displayed significant chang at 0.5rot. Conclusion The cells displayed significant changes with obvious Tca8113 cell prolifera-tion inhibition and hold - up cell cycle after being exposed to alternating magnetic field of different intensity. But human squamous tongue cancer ceils could not be induced to apeptosis.

Effects of alternating magnetic field on the metabolism of the healthy and diabetic organisms

The aim of this study was to determine the effects of alternating magnetic field on the metabolism of the healthy and diabetic rats. The rats were divided into two experimental groups. Magnetic fields of 5 and 8mT intensity was applied to the first group of rats for 3 weeks (C5mT, CMF5mT, C8mT and CMF8mT). The second group was identified as diabetics group and 5mT was applied (D5mT and DMF5mT). The control groups (C5mT, C8mT, D5mT) of applied magnetic fields were placed in the same cage of the rats in experimental groups that have the same conditions but no pass current. The weights of rats exposed to magnetic fields in experimental groups were increased to initial weight; the plasma glucose levels were decreased in the blood parameters of the healthy and diabetic rats that they were exposed to 5mT and 8mT intensity magnetic fields. The decrease of the level of the total cholesterol and triglyceride in the blood plasma of the rats, showed that magnetic fields affected the hormonal systems, directly or indirectly, and slowed down the metabolism or hidratation.

Magneto-heating Effect and Cytotoxicity of Carbonyl Iron Powder in Arterial Embolization Hyperthermia / 中国微创外科杂志

Objective To evaluate the magneto-heating effect and cytotoxicity of the carbonyl iron powder as a feasibility for arterial embolization hyperthermia. Methods Different doses of carbonyl iron powder suspensions were prepared in vitro(10 mg/ml,100%;10 mg/ml,50%;or 64 g/L phenol solutions),and heated for 20 minutes in an alternating magnetic field(49.9,79.9,and 110.2 Oe).The influences of the doses of suspensions and currency of magnetic field on the heating effect were observed.Meanwhile,mouse fibroblast L-929 cells were cultured with the suspensions for 2,4,or 7 days.The morphology and relative growth rate(RGR) of the cells were determined by microscopy and MTT assay.The cytotoxicity of the suspensions was then classified. Results The heating ability of the carbonyl iron powder increased with the suspension concentration and the strength of the magnetic field.A optimal therapeutic temperature was achieved at 110.2 Oe with 60 mg/ml carbonyl iron powder suspension.The L-929 cells showed normal morphology after been treated by the carbonyl iron powder(10 mg/ml 100% solution and 50% solution) for 2,4 and 7 days with the 0-1 degree cytotoxicity.Conclusion The carbonyl iron powder has good heating effect under the alternating magnetic field,and is compatible with the tested cells.

Thermoseed Inductive Heating in vivo and in vitro and Its Impact on Immune Function of Tumor Bearing Rats / 中国微创外科杂志

Objective To evaluate the heating ability of thermoseeds in alternating magnetic field and its therapeutic effects on tumor bearing rats with simultaneously detected immune function. Methods To monitor the temperature increase of thermoseeds in vitro,of which the Curie point was 57 ℃ or 70 ℃.Forty Wistar rats implanted with Walker-256 cells were randomly divided into five groups: C group(control group,10 rats),M group(magnetic control group,5 rats),T group(thermoseeds control group,5 rats) and two heating treatment groups(H1 group,10 rats and H2 group,10 rats).In the H1 group,two thermoseeds with a Curie point at 57 ℃ were implanted into the tumor tissues in each rat with a heating time of 30 minutes,while in the H2 group,two thermoseeds with a Curie point at 70 ℃ were used with a heating time of 6 minutes.Five rats from each group were killed 9 days after the heating therapy to evaluate the volume and weight of the tumor tissues.The peripheral blood T-cells were counted in the rest rats in the H1,H2,and C groups. Results Magnetic inductive heating of the thermoseeds in vitro can reach the Curie point.The median tumor volume in the H2 group was 0.50 cm3(0.00-26.54),which was significantly lower than that in the M group(36.18 cm3,0.96-39.90,Z=2.21,P=0.032).And the weight of the tumors in the H1 and H2 groups was significantly lower than that in the M group [0.96 g(0.00-21.18) in H1 and 0.41 g(0.00-23.40) in H2 vs 31.45 g(1.09-36.09) in M group,Z=2.21 and P=0.032 for both].In the peripheral blood,the percentage of CD4+ T-cells was(22.39?5.27)% in H1 group,and(24.76?5.19)% in H2 group,which were significantly higher than that in C group [(12.07?4.45)%,P=0.01 and 0.003 respectively];and the percentage of CD8+ T-cells in the H2 group was significantly higher than that in the C group [(19.58?4.63)% vs(12.72?3.96)%,P=0.04].Conclusions Thermoseed had a good heating ability in alternating magnetic field and its inductive heating can inhibit tumor growth in Wistar rats and improve the immune function of the rats.

Effects of Intermediate Frequency Alternating Magnetic Field on Blood Analysis and Histopathological Analysis for Important Organs in Mice / 中国微创外科杂志

0.05).Histopathological examination showed no pathological change in the brain,liver,kidneys,and spleen of the mice,but reduced spermatogenic cells spermatozoa.The sperm motility was(40.58?7.75)% in the control,(7.40?1.06)% in the experiment group 1(q=16.909,P0.05).No significant difference in the sperm densities was found among the groups.Conclusions Intermediated alternating magnetic field has adverse effects on the reproduction of mice.Testosterone is one of the target organs of electromagnetic radiation.It is sensitive to IF magnetic field(40 kHz,28 mT).Blood,brain,liver,kidney and spleen of mice are not effected by IF alternating magnetic field.