ABSTRACT
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.
ABSTRACT
Objective To establish an ion-pair reverse-phased high-performance liquid chromatography (RP-HPLC) method for simultaneous determination of ATP, ADP and AMP in the hippocampus of mice. Methods The protein of mouse hippocampus was precipitated with perchloric acid, and neutralized with potassium carbonate-methanol mixture. Mobile phase was as follows: 50 mmol/L phosphate buffer (buffer for K2HPO4-KH2PO4, pH 6.60, containing 22% methanol, and 4 mmol/L tetrabutylammonium bisulfate). Shimadzu HPLC system and Agilent C18 column (4.6 mm×250 mm, 5 μm) filled with the same material pre-column (12.5 mm×4.6 mm, 5 μm) were used. The contents of ATP, ADP and AMP in mouse hippocampus were analyzed at a wavelength of 254 nm, the flow rate of 0.6 ml/min and room column temperature. Results Stability tests showed that intra-day and inter-day precision of the method were 1.27%-3.42% and 0.88%-3.52%, respectively, and recovery rates were 95.67%-104.05%. Conclusion The HPLC method established in this study is simple, accurate and efficient in detecting the levels of ATP, ADP, and AMP in mice hippocampus.
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<p><b>OBJECTIVE</b>To investigate the mechanisms underlying the incorporation of microparticles(MP) derived from human bone marrow mesenchymal stem cells (MSCs) into human umbilical cord endothelial cells (HUVECs).</p><p><b>METHODS</b>MPs were isolated from the supernatants of MSCs which had exposed to a hypoxia/serum-deprivation condition. Electron microscope was used to identify the MPs. The surface molecule profile was evaluated with the bead-based flow cytometry technique. The expression level of the phosphatidylserine receptor (PSR) was detected by immunofluorescence cytochemistry. MPs were co-cultured with HUVECs in the presence or absence PSR-antibody, and the internalization of MPs was observed with laser scanning microscopy.</p><p><b>RESULTS</b>The MPs derived from MSCs expressed highly PS, while PSR expressed on the surface of HUVECs. The confocal result revealed that MPs could quickly be uptaken by the endothelial cells, and mainly distributed in the cytoplasm surrounding of the nuclei. The internalization of MPs reduced significantly after PSR specific blockage.</p><p><b>CONCLUSION</b>The reaction between PS on the MP and the PSR of HUVECs plays an important role in the internalization of MSC-MPs.</p>
Subject(s)
Humans , Cells, Cultured , Coculture Techniques , Endothelial Cells , Flow Cytometry , Mesenchymal Stem Cells , Umbilical CordABSTRACT
<p><b>OBJECTIVE</b>To investigate the protection of silymarin against the human mesenchymal stem cell (MSC) apoptosis induced by serum deprivation and its underlying mechanism.</p><p><b>METHODS</b>Human umbilical cord MSCs were cultured in the absence of serum, and the silymain of different concentration (1-10 µg/ml) was added into the medium. MTT test was performed to observe the cell proliferation status. After being cultured for 72 hours, the cells were collected, and flow cytometry with Annexin-V-PI double-staining was used to detect the apoptotic cells from the control and silymarin-treated groups. Furthermore, the intracellular contents of BAX and BCL-2 were detected by Western blot for exploring the potential mechanism.</p><p><b>RESULTS</b>The silymarin promoted the proliferation of human UC-MSCs in a dose-dependent manner, reaching its maximal at a dose of 5 µg/ml. Moreover, silymarin could inhibit the serum deprivation-induced apoptosis of MSCs and, the inhibitory rate reached up to 30% when it was added at a concentration of 5 µg/ml. The content of intracellular BAX was obviously elevated after serum-deprivation treatment, and this increase could be blunted by the addition of silymarin. Meanwhile, the content of BCL-2 was not obviously changed.</p><p><b>CONCLUSION</b>The silymarin can stimulate MSC growth and inhibit the apoptosis of MSCs probably by the mitochondria pathway.</p>