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Medical magnetic nanoparticles are nano-medical materials with superparamagnetism, which can be collected in the tumor tissue through blood circulation, and magnetic particle imaging technology can be used to visualize the concentration of magnetic nanoparticles in the living body to achieve the purpose of tumor imaging. Based on the nonlinear magnetization characteristics of magnetic particles and the frequency characteristics of their magnetization, a differential detection method for the third harmonic of magnetic particle detection signals is proposed. It was modeled and analyzed, to study the nonlinear magnetization response characteristics of magnetic particles under alternating field, and the spectral characteristics of magnetic particle signals. At the same time, the relationship between each harmonic and the amount of medical magnetic nanoparticle samples was studied. On this basis, a signal detection experimental system was built to analyze the spectral characteristics and power spectral density of the detected signal, and to study the relationship between the signal and the excitation frequency. The signal detection experiment was carried out by the above method. The experimental results showed that under the alternating excitation field, the medical magnetic nanoparticles would generate a spike signal higher than the background sensing signal, and the magnetic particle signal existed in the odd harmonics of the detected signal spectrum. And the spectral energy was concentrated at the third harmonic, that is, the third harmonic magnetic particle signal detection that meets the medical detection requirement could be realized. In addition, the relationship between each harmonic and the particle sample volume had a positive growth relationship, and the detected medical magnetic nanoparticle sample volume could be determined according to the relationship. At the same time, the selection of the excitation frequency was limited by the sensitivity of the system, and the detection peak of the third harmonic of the detection signal was reached at the excitation frequency of 1 kHz. It provides theoretical and technical support for the detection of medical magnetic nanoparticle imaging signals in magnetic particle imaging research.
Assuntos
Magnetismo , Nanopartículas de MagnetitaRESUMO
Aim Toconstructthreeplasmidsincluding Smad3 WT,Smad3 EPSM and Smad3 3S-A stable transfection in HepG2 cell lines to investigate phospho-domains of Snad3(pSmad3C or pSmad3L),their pro-tein expression and roles in HepG2 cell proliferation, apoptosisandcellcycle.Methods Threeplasmidsin-cluding Smad3 WT (Carry the wild Smad3 gene ), Smad3 EPSM(Carry the mutated phosphorylation site in linker region of Smad3 gene)and Smad3 3S-A(Car-ry the mutated phosphorylation site in C-terminal of Smad3 gene)were respectively transfected into HepG2 cells by using a liposome transfection reagent.Verifi-cation of positive cells was done by screening with G418 via co-culture.Transfection efficiency was deter-mined by Western blot.Cell proliferation was induced by exogenous TGF-β1 in the respective stably transfect-ed HepG2 cell lines.Cell proliferation was monitored by MTT.Cell cycle and apoptosis were determined by flowcytometry(FCM).Results Therewaselevated protein expression of the respective phospho-domain sites in the stably transfected HepG2 cells for Smad3 WT(C-terminus and Linker),Smad3 EPSM(C-termi-nus)and Smad3 3S-A(Linker),which indicated suc-cessful stable transfection of HepG2 cell lines.The re-sults from MTT experiment showed that TGF-β1 could induce proliferation of HepG2 cells with or without the transfection of Smad3 WT,Smad3 EPSM and Smad3 3S-A plasmids,meanwhile transfected Smad3 EPSM plasmids could significantly inhibit proliferation of HepG2 cells induced by TGF-β1 , and transfected Smad3 3S-A plasmids accelerate proliferation of HepG2 cells induced by TGF-β1 .Cell cycle analysis showed that the G0/G1 phase of HepG2 cells with stable trans-fection of Smad3 EPSM plasmid increased compared with HepG2 cells with or without stable transfection of Smad3 WT plasmid,meanwhile the G2/M phase of HepG2 cells with stable transfection of Smad3 3 S-A plasmid increased.Compared with Smad3 WT trans-fected cells, apoptosis in Smad3 EPSM transfected cells was markedly increased,while that of Smad3 3S-Atransfectedcellsdecreased.Conclusions Thethree plasmids of Smad3 WT,Smad3 EPSM and Smad3 3S-A stably transfected HepG2 cell lines have been suc-cessively constructed.The construction of three plas-mids transfected HepG2 cell lines provides the research foundation for studying medical as well as possible reg-ulatory mechanism of pSmad3 C/pSmad3 L.
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Objective:To investigate the differentially expressed genes of gastric mucosa of precancerous lesion of chronic atrophic gastritis (CAG) in rats intervented by promoting blood flow therapy of TCM,and to analyze its mechanism at genetic level. Methods:The model of precancerous lesion of CAG rats was induced by spring insertion and intragastric administration of NaCl solution and hot paste. To detect the differentially expressed genes of precancerous lesion of CAG rats by gene chip technology,and the main differentially expressed genes were indentified by real-time PCR. Results:Compared with blank group,HSP70 and ptk2 significantly reduced in natural recovery group,the HSP70 expression increased signifi cantly after being treated with supplementing qi for promoting blood flow,and ptk2 expression increased obviously after being treated with regulating qi and promoting blood flow. The results of real-time PCR in expression level of HSP70mRNA and ptk2mRNA were the same as that of the gene chip technology. Conclusion:Supplementing qi for promoting blood flow can upregulate HSP70,thus inhibit precancerous lesion of CAG in rat gastric mucosal cell apoptosis and promote mucosal repair; Regulating qi and promoting blood flow can up-regulate ptk2,sequentially regular remodeling of actin cytoskeleton and promote repairing and healing of injury gastric mucosal. These may be one of mechanism that supplementing qi for promoting blood flow and regulating qi and promoting blood flow treat precancerous lesion of CAG.