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Atrial fibrillation, also known as atrial fibrillation, is a common cardiac arrhythmia, and its incidence increases with age. Catheter ablation is considered to be an effective means to treat atrial fibrillation and maintain sinus rhythm. The common ablation technologies are radiofrequency ablation and cryoablation. However, the existing catheter ablation technology has a "zero-sum effect", and it is difficult to control the optimal dose clinically. In this study, a new method of pulsed electric field ablation for atrial fibrillation was proposed, which effectively solved the "zero-sum effect" problem of temperature ablation. The clinical application results show that the proposed technology effectively overcomes the shortcomings of existing temperature ablation, and can form durable pulmonary vein isolation.
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Objective To explore the effects of 3-mercaptopropionic acid (3-MPA) coated CdSe-CdS/ZnS quantum dots (3-MPA-QDs) on the uptake , proliferation and migration of human umbilical vein endothelial cells (HUVEC), and to study the biotoxicity of 3-MPA-QDs, so as to provide the theoretical basis for the development of quantum dot photosensitizers . Methods The short-term ( 6 h ) uptakes of 3-MPA-QDs and the small molecule photosensitizer protoporphyrin IX (PpIX) in HUVEC cells were real-time observed and compared by a laser confocal scanning microscope. Besides, the uptakes within 48 h as well as the effects of the uptake on morphology and proliferation of HUVEC were also observed. The effect of 3-MPA-QDs on the migration of HUVEC cells within 24 h was observed using a grid dish. LysoTrackerTM Deep Red was used to label lysosomes, and the endocytosis mechanism of 3-MPA-QDs was observed by fluorescence co-localization. Results The fluorescence of 3-MPA-QDs in the HUVEC showed a continuous rising trend within 6 h, weakened after 24 h, and then turned weaker after 48h of the uptake, which is different from the"up-saturation"absorption pattern of PpIX. However, the fluorescence signal was still clear and bright which indicate 3-MPA-QDs were passaged into newborn cells. Migration experiments showed that the target cells carrying 3-MPA-QDs migrated 50 μm grids within 24 h, indicating the cell migration ability was not significantly affected. Co-localization results showed that 3-MPA-QDs localized in lysosomes. Conclusions The 3-MPA-QDs localized in lysosome, and they were easy to be absorbed and hard to be excreted by HUVEC. However, no obvious effects of 3-MPA-QDs were observed on cell proliferation and migration.
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Objective To investigate the photochemotherapeutic effect and the main affecting factors of PSD-007 on human cervical cancer Hela in vitro.Methods Hela cells were treated with different concentrations of PSD-007 (0,3.125,6.25,12.5,25,50,100 μg/ml) for 2 h under the influence of low-level laser (635 nm) therapy at different doses (0,0.6,1.2,2.4,4.8,9.6 J/cm2).Then the OD values and survival rates of Hela cells were measured by MTT assay compared with breast cancer cells MCF-7 in same treatment.Hela cells were treated with 12.5 μg/ml of PSD-007 for 2 h and were treated with different intensities of laser (1.2,2.4,4.8 J/cm2).The cellular apoptosis rate and cell cycle phase distribution of Hela were measured by a flow cytometry (FCM).Results Survival rates of Hela cells declined with more than 25 μg/ml of PSD-007 only,and significant difference in the inhibitory between the PDT group and control group was observed (P＜0.05).The survival rates of Hela after PDT was decreased by the concentration of sensitizer and dose of laser.There were no significant differences of cell survival rates among the groups with concentrations more than 12.5 μg/ml and laser energy density more than 4.8 J/cm2.The FCM assay showed a G0/G1 cell cycle arrest in a time-dependent manner.Conclusions PSD-007 has a photodynamic effect on Hela in vitro.Photodynamic effect of PSD-007 was more significant in Hela than MCF-7.Less photosensitizer and laser energy density were needed.
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Objective To investigate the influence of hypoxia-reoxygenation on the myocardin gene expression of cultured rats' vascular smooth muscle cells(SMC).Methods The SMC were isolated from the media of the thoracic aorta vessel of Sprague-Dawley rats,and cultured with attachment-block manner.The morphology and cell counting of the cultured cells under hypoxia conditions were observed and comparedto that under normal culture condition.Total RNA extracted from the cultured cells,the expression of myocardin mRNA in SMC were measured at hypoxia status and at various time after reoxygenation through RT-PCR.Results The rats' vessel SMC was successfully cultured and showed a "peak-valley" shape.Self-made hypoxia equipment can produce a lower oxygen partial pressure without significant variation of pH value which met the experiment requirements in 2 4 hours .However,in the hypoxia conditions,the expression level of myocardin was lowest at the 12th hours,then increased.After 24 hours of hypoxia,the expression levels of myocardin began to increase at the 6th hour of reoxygenation and reached a normal level at the 12th hour of reoxygenation.Conclusions Hypoxia-reoxygenation has an effect on the expression of myodardin gene.