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Objective To evaluate left atrial function dynamic changes before and after radiofrequency catheter ablation (CA)with persistent atrial fibrillation (AF)and predict the maintain sinus rhythm of postoperative atrial fibrillation by speckle tracking imaging.Methods The study was including 45 cases underwent CA with persistent AF(preoperative 1 week,postoperative 24 hours,3 months,6 months)and 25 normal cases.Left atrial function and strain rate were analysed.These index were measured and calculated:the left atrial diameter index (LADI),left atrial area index (LAAI),left atrial maximum volume index (LAVImax)and left atrial ejection fraction(LAEF),left atrial wall strain rate of left ventricular systolie (SRs),left atrial wall strain rate of left ventricular early diastolie (SRe),left atrial systolic strain rate(SRa) and the average of left atrial wall each phase strain rate.Results ① LADI,LAAI,LAVImax were significantly increased;LAEF,SRs,SRe were decreased significantly;SRa were disappeared with AF compared with the control group.②LADI,LAAI,LAVImax decreased gradually,LAEF,SRs,SRe,SRa were gradually increased with the extension of the follow-up time.③Left atrial average SRs predicted maintenance of sinus rhythm with atrial fibrillation after operation of CA(odds ratio=0.607,95% CI=0.417-0.819,correction of P =0.017)was an independent predictor.Conclusions Speckle tracking imaging can quantitative evaluate left atrial function with persistent AF after CA.Left atrial global reservoir function predicts the efficacy of CA.
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Objective To detect biofilm formation and biofilm-associated genes of methicillin-resistant Staphylococcus aureus (MRSA) in clinical isolates. Methods The biofilm were determined by microtiter plate assay (MPA) and congo red agar (CRA) and the biofilm-associated genes icaA,sarA,fnbA,fnbB were detected by PCR in 33 strains of MRSA in clinical isolates. Results Of the 33 MRSA isolates, 29(87.9%) were MPA positive, 16(48.5%) were CRA positive; The icaA gene was present in 39.4% of isolated strains. Furthermore, 69.7% of strains harboured the sarA gene, 39.4% were fnbA positive and 75.8% were fnbB positive. As many as 87.9% strains had the ability to form biofilm in vitro. 44.8% of MRSA formed biofilm in ica-dependent mechanism and 55.2% of MRSA isolates formed biofilm in ica-independent mechanism. Of the biofilm positive MRSA, 75.9% were sarA positive, 37.9% were fnbA positive and 79.3% were fnbB positive. Conclusion Most of the MRSA strains formed biofilm in ica-independent mechanism. fnbB and sarA gene shows higher frequency among the biofilm-associated genes of MRSA, it may infer that most of the MRSA strains biofilm formation are fnbB-mediated. Meanwhile, sarA may be a positive regulator of fnbB, and thus drives the biofilm formation.
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Objective To investigate the role and mechanism of signal transducer and activator of transcription 4 (STAT4) in homocysteine (Hcy)-induced proliferation,migration and senescence of human aorta smooth muscle cells (VSMCs).Methods After VSMCs were incubated with Hcy (0-0.50 mmol/L) for various time periods,a CCK-8 assay was performed to determine proliferation activity.Modified Boyden chamber system (Transwell apparatus) was used to examine migration ability.A SA-β-gal staining kit was used to determine senescence status.Western blotting was performed to examine the expressions of STAT4 and phosphorylated STAT4 (p-STAT4) proteins,and ELISA was performed to examine MCP-1 expression.Results Hcy (from 0.05 mmol/L) significantly increased the proliferation of VSMCs (P ＜ 0.05).Hcy (from 0.10 mmol/L) significantly increased the migration of VSMCs (P ＜ 0.05).Hcy promoted the senescence of VSMC in a concentration-dependent manner,and significantly increased VSMC senescence when the concentration of Hcy reached 0.10 mmol/L (P ＜ 0.05).Hcy (from 0.10 mmol/L) treatment significantly increased the expression of p-STAT4 (P ＜ 0.05) and MCP-1 (P ＜ 0.05).Conclusions Hcy increases the proliferation,migration and senescence of VSMCs,probably by the activation of STAT4 pathway.
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Objective To investigate the efficacy and safety of catheter radiofrequency ablation of paroxysmal supraventricular tachycardia.Methods From Jul 2003 to Jan 2011,1106 cases with narrow QRS complex tachycardia who were treated by catheter radiofrequency ablation were recruited from our center and followed up for the rates of successful treatment,rcurrence and complications.Results There were in total 1106 patients (atrioventricular reentrant tachycardia:588 ; atrioventricular nodal reentrant tachycardia:477; atrial tachycardia:41 ),with a sex proportion of 1∶1.Successful ablation rate was 98.3 ％ (1087/1106).Of the 1087 successful ablation cases,43 (3.9％ )were warranted repeated ablation.The recurrent rates for trioventricular nodal reentrant tachycardia,atrioventricular reentrant tachycardia,left accessory pathway and right accessory pathway were 1.5％,5.6％,3.9％,and 9.1％ respectively.Complication rate was 1.5％.The major complications included pheumothorax ( 6 cases ),pulmonary embolism ( 1 case ),transient third-degree atrioventricular block ( 2 cases ),first-degree atrioventricular block ( 3 cases ),and persistent third-degree atrioventricular block(2 cases)with pacemaker implantation.There was one case of cardiogenic sudden death 5 days after the treatment procedure.The cause of his death was chronic stroke-related but not related to the operation procedure.Conclusion Catheter ablation has high efficacy and low complication rate in long-term follow-up,and is a promising treatment for paroxysmal supraventricular tachycardia.
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Objective To investigate the influence of erythropoietin in the metabolism of extracellular matrix after myocardial ischemia-reperfusion injury.Methods The langendroff reperfusion system was applied to investigate the protective function of EPO in ischemia-reperfusion condition in rats.The effects of EPO on extracellular matrix were observed by Western blot and signal pathway blocker.The LVEDP and infarction area were observed at the same time.Results EPO significantly improved LVEDP [(19.8±0.2) mmHg vs (35.9±0.2) mmHg,IR group vs EPO +IR group,P＜0.05]and decreased infarction area (35.26%±7.13% vs 62.70%±7.23%,IR group vs EPO+IR group,P＜0.05).The expression of MMPs was significantly decreased and the expression of collagenase Ⅰ/Ⅲ was significantly enhanced by EPO (MMP2 53.2+2.6 vs 21.2+2.5;MMP9 57.6±3.1 vs 19.2±2.6;IR group vs IR+EPO group (P＜0.05);collagen Ⅰ 43.2±2.2 vs 11.4±2.3;collagen Ⅲ 55.3±3.2 vs 18.1 vs 2.3;IR+EPO group vs IR group (P＜0.05).This function can be inhibited by Mek-Erk inhibitor.Conclusion EPO plays a role in the metabolism of extracellular matrix by Mek-Erk signal pathway,which can protect the heart tissue from ischemia-reperfusion injury.
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Objective Accelerated junctional rhythm (AJR) always occur during slow pathway catheter ablation for atrioventricular nodal reentrant tachycardia (AVNRT), the clinical significance of it has not been gotten in agreement. The aim of this study is to search for an association between AJR and ablation target site or tachycardia recurrence.Methods The data of 247 patients with AVNRT who received radiofrequency ablation procedure during April 1995 to October 1999 was analyzed. All these people were divided into two groups (212 patients in the successful ablation group or group 1, 35 patients in the recurrence group or group 2). The AJR was divided into two distinct pattern:type Ⅰ(continuous AJR that persisted until the end of energy delivery) and type Ⅱ (intermit AJR alternated with sinus rhythm during slow pathway ablation, which was eliminated immediately when stopping energy delivery ). Results\ The results showed that patients in group 1 exhibited better AJR response, most of them were seen with type Ⅱ AJR. However most of the people in group 2 had no AJR response throughout energy delivery , few of them had type Ⅰ AJR response. The AJR response of group 1 started relatively earlier than that of group 2(3 2?1 8 vs 5 7?2 5 ,P