BACKGROUND: The implantation of electronic devices has become the preferred treatment tor symptomatic bradyarrhythmias.However,there are many shortcomings in electronic pacemakers.The usage of molecular biology principle to develop biological pacemaker has become a topic of discussion in research.When sinoatrial node is lnhlblted,pacemaker effect runs by transfecting hyperpolarization-activated cyclic nucleotide-gated(HCN)channel gene of If current,overexprcssing HCN,and increasing inward current in diastolic phase of the heart.Construction of biological pacemakefs by gene therapy and cell therapy may become an optimal substitute of electronic pacemakers in the near future.OBJECTIVE:To sum up the research advancement in application of HCN channel gene to the development of biological pacemaker.RETRIEVAL STRATEGY:The relevant articles published between January 1979 and June 2007 were searched for in Pubmed database by researcher of this article with the key words of"hyperpolarization-activated cyclic nucleotide-gated chartnel,biological pacemaker"in English.157 articles were selected and reviewed by the inclusive cntena of:① articles closely related with the application of HCN to the development of biological pacemaker;②the late articles and articles in anthority journals in the same field.Exclusive criterion:repetitive studies.LITERATURE EVALUATION:The main sources of literatures were randomized clinical trial(RCT)on biological pacemaker by HCN.Among 36 selected articles,10 were reviews,and others were elementary expenInental studles.DATA SYNTHESIS:①Of all four HCN isoforms,HCNI,HCN2,and HCN4 are the main isoforms in the heart.HCN3 only expresses in embryonic pacemaker cells in a low level.HCN2 highly expressed in low pacing regions(Ventricular muscle),whereas HCN4 highly expressed in high pacing regions.Moreover,HCN2 are the main isoforms in the ventricle.Expression ratio of HCN2 to HCN4 is 5:1 in neonate rats and 13:1 in adult rats.②Defects in HCN channels may underlie sick-sinus syndrome.③Up to now,HCN genes of If current contribute importantly to the generataon of the regular pacemaker potential.CONCLUSION:Gene therapy and cell therapy have become an optimal approach to improve biological paccmakers.Application of HCN channel gene in development of biological pacemaker may hold great promlse In the treatment of chronic arhythmia.

Objective To investigate the protective effects of Bauhinia championii Benth flavones(BCF) on oxidative stress of neonatal rat cadiocytes induced by H2O2.Methods Cadiocytes of neonate rat was cultivated for 72 hours and divided into six groups: a normal control group, a H2O2 group, BCF(60, 120 and 240μg/ml)+H2O2 groups and aShuxueninginjection (100μg/ml)+H2O2 group (n=8). 6 hours after the drugs were given, the morphology changes was observed and the survival rate was detected; the content of AST, CPK, LDH in culture medium were detected; the activity of SOD, CAT, GSH-Px and the content of MDA in cardiomyocytes were also determinted; the apoptosis rate were detected, and the expression of caspase-3 in cardiomyocytes was detected by Western blot.Results Compared with the H2O2 group, the activity of AST(28.8 ± 6.1 U/ml, 24.5 ± 5.3 U/mlvs. 36.2 ± 6.7 U/ml), CPK(1.8 ± 0.4 U/ml, 1.5 ± 0.3 U/mlvs. 2.5 ±0.4 U/ml), LDH(805.2 ± 160.9 U/L, 671.5 ± 128.7 U/Lvs. 916.5 ± 168.4 U/L) in culture medium were significantly decreased (P<0.05,P<0.01), the activity of SOD(84.8 ± 17.4 U/mg, 95.3 ± 18.2 U/mgvs. 55.7 ± 13.1 U/mg), CAT(23.4 ± 3.1 U/mg, 26.3 ± 3.5U/mgvs. 15.2 ± 3.0 U/mg) in cardiomyocytes were significantly increased and the content of MDA(8.1 ± 1.7 nmol/mg, 6.8 ± 1.5 nmol/mgvs. 11.1 ± 2.3 nmol/mg) were significantly decreased (P<0.05,P<0.01), the expression of c caspase-3(1.64 ± 0.16, 1.30 ± 0.12vs. 2.06 ± 0.25) and the apoptosis rate (24.2% ± 5.5%, 13.4% ± 3.9%vs. 51.2% ± 9.1%) were significantly decreased (P<0.05,P<0.01); the activity of GSH-Px (3.6 ± 0.9 U/mg vs. 2.4 ± 0.7 U/mg) in cardiomyocytes of BCF 240μg/ml treatment group was increased (P<0.05).Conclusions BCF could effectively improve the morphology of neonatal rat cadiocytes induced by H2O2, increase the survival rate, improve the activity of antioxidase, down-regulate the expression of caspase-3 and decrease the apoptosis rate, suggesting that BCF had dose-dependent protective effects on oxidative stress of neonatal rat cadiocytes induced by H2O2.

Objective To compare the influence degree of laparoscopic operation and open operation on peripheral blood T lymphocyte subsets and Th1Th2 in patients with severe acute pancreatitis.Methods 54 patients who underwent surgical treatment in our hospital from February 2013 to December 2014 were selected as the subjects, 27 patients with severe acute pancreatitis who were treated with open operation as group A , 27 cases who were treated with laparoscopic operation at the same time were selected as group B , and then the peripheral blood T lymphocyte subsets and serum Th1Th2 indexes of two groups before the operation and at first,third and seventh day after the operation were respectively detected, then the detection results of two groups were compared.Results The peripheral blood T lymphocyte subsets and serum Th1Th2 indexes of group B at first, third and seventh day after the operation were all significantly better than those of group A , the difference was statistically significant ( P<0.05 ) , and the detection results of group A and group B at third day after the operation were worse than those at other time , the difference was statistically significant (P<0.05).Conclusion The influence of laparoscopic operation and open operation on T lymphocyte subsets and Th1Th2 in peripheral blood of patients with severe acute pancreatitis, the adverse effects of laparoscopic operation on the above indicators were relatively small.

Objective To measure various parameters with tissue Doppler imaging, quantitatively score left ventricular wall motion, assess longitudinal wall motion in total and regional myocardium of myocardial infarction patients. Methods Tissue tracking was adopted for assessing left ventricular regional myocardium of 30 myocardial infarction patients (MI group) and 30 normal subjects (control group). After collecting dynamic images and analyzing information off-line, maximum displacement along long axis asynchronously in annular, basal, mid and apical segments of different walls were acquired, and left ventricular wall motion score indexes(TT score indexes) were calculated. Results Maximum displacement in different segments of left ventricular regional myocardium was lower in MI group than control group, especially in infarcted segments. TT score indexes were lower in MI group than control group( 6.23? 1.93 vs 9.71? 1.08, P

Objective To observe longitudinal motion characteristics of regional myocardium in left bundle branch block(LBBB) patients. Methods Left ventricular regional myocardium of 15 LBBB patients and 15 normal subjects were assessed by tissue Doppler imaging(TDI). Peak velocities(V_S,V_E,V_A) during isovolumic contraction, ejection, isovolumic relaxation, early relaxation, atrial systole phases and maximum time velocity integral(TVI_(max)), displacement(D_(max)) in mitral(tricuspidal) annulets of different walls were measured. Furthermore, the different parameters from the beginning of electrocardiogram QRS wave to the beginning of S wave(Q-Sb),to the tip of S wave(TTP), the acceleration time of IVC wave(IVA), the acceleration time of the E wave(Eac),the durations of different phases(IVC,S,IVR,D)and IVC/S and others were acquired. Results Peak velocities(V_S,V_E)and TVI_(max) in left ventricular septal, inferior, anterior, posterior walls were lower in LBBB group than control group; those parameters in different segments of left and right ventricular lateral myocardium were not significantly lower in LBBB group than control group. What is more, D_(max) of mitral annular sites in LBBB group were lower than control group. Q-Sb, TTP and IVC in left ventricular septal, inferior, anterior, posterior walls were longer in LBBB group than in control group; IVA lengthened, Eac and Edc shortened in left ventricular septal, inferior walls; IVR lengthened, diastole shortened, IVC/S increased in left ventricular septal, inferior, and posterior walls. Conclusions Abnormal left ventricular activation sequence during LBBB caused obvious impairment in total and regional systolic and diastolic function. And delayed contraction with different degrees were resulted from different walls of left ventricle with intraventricular dyssynchrony; but contraction in right ventricle was not significantly delayed, with interventricular dyssynchrony.

Objective To evaluate the safety and efficacy of the temporary bedside cardiac pacing in controlling torsades de points (TdP) in patients with acquired long QT syndrome (LQTS). Methods Twelve patients with acquired LQTS were enrolled from April 2003 to August 2007 consecutively and their clinical data were analyzed. Bedside cardiac pacing was adopted when other methods couldn't terminate the repeated TdP. Results Twelve patients successfully experienced the temporary bedside cardiac pacing via femoral venous. The average time spent in bedside cardiac pacing was about (10.5±2.4) min. After cardiac pacing the interval of QT and QTc were shortened [ (0.42±0.03 ) svs (0.52±0.06) s, P < 0.05; (0.43± 0.04 ) s vs (0.53±0.05 ) s, P <0.05 ]. The TdP occurred (4.6±1.2 ) times per day before cardiac pacing and it didn't reoccur any more after bedside cardiac pacing. The average time for cardiac pacing was(3.8±1.4) d. When the patients were discharged, the interval of QT and QTe were (0.41±0.02) s and (0.42±0.05) s respectively, there were significant differences compared with that before cardiac pacing(P< 0.05). During 1 year follow-up, the patients didn't experience TdP any more, and the interval of QT and QTe were (0.41± 0.06) s and (0.42±0.05) s respectively. Conclusion The immediate bedside cardiac pacing is a safe and effective way to control the repeated TdP.

Objective To evaluate the diagnostic value of deep venous thrombosis(DVT)on lowerlimb venous ultrasonography combined with right ventricular dysfunction (RVD) on transthoracic echocardiography(TTE) in patients with acute pulmonary thrombo embolism(PTE). Methods This prospective multicenter control trial included 520 patients with confirmed acute PTE from 41 hospitals between June 2002 and February 2005.Results The incidence of RVD and DVT was associated with the severity of PTE.There were 57.0%(207/363)patients with RVD,49.6%(1 80/363)patients with DVT,265(73.0%)patients with RVD and/or DVT,and 121(33.3%)patients with combined sign of DVT plus RVD in the whole population.As to major PTE population,206(99.5%)patients had RVD and 121 (58.5%)patients had DVT.In addition,the rate of RVD was much greater in proximal PTE than in lobar PTE and segmental PTE(78.7%,51.4%and 21.7%,respectively,P＜0.001).DVT occurred more frequently in proximal PTE than in lobar PTE and segmental PTE(61.7%,46.8%and 37.0%,respectively,P＜O.001).The incidence of the combined sign was 51.1%,24.3%and 8.7%,respenctively (P＜0.001).Conclusions The incidence of the combined sign of RVD plus DVT was associated with the severity of PTE and the localization of emboli.The combined sign of RVD plus DVT help diagnose major PTE especially in emergency department.

BACKGROUND: Posterior lumbar interbody fusion(PLIF) has been an effective method for treating the instability of the lumbar spine.OBJECTIVE: To explore the changes in mobilization range after treatment of lumbar segmental instability with titanium-coated fusion cages (Prospace).DESIGN: A before-and-after controlled observational trial based on the patients.SETTING: Orthopedic department of a university-affiliated hospital.PARTICIPANTS: Totally 16 patients with lumbar instability(4 males and 12 females aged 37 to 68 years with the average age of 51.6 years) were treated by posterior lumbar interbody fusion(PLIF) using titanium-coated cage from December 2002 to. December 2003. There were 4 cases of disc herniation, 6 lumbar spinal stenosis, 3 degenerative spondylolisthesis and 3 isthmic spondylolisthesis, among which 5 cases were spondylolisthesis Ⅰ and one spondylolisthesis Ⅱ.METHODS: All the cases received PLIF. In each case, double cages were inserted with the postlateral bone graft and pedicle screw systems were supplemented. The radiology and clinical effects before and after operation were compared.MAIN OUTCOME MEASURES: ① The average height of disc space and foramina and mobilization range of the vertebral bodies before and after operation; ② The Oswestry Disability Index score.RESULTS: All the cases were followed up for 6 to 16 months with an average of 12 months. The total fusion rate was 100%, and the postoperative height of disc space and foramina recovered satisfactorily. The Qswestry Disability Index score was 44. 2 ± 3.9 before operation and 25.5 ± 3.6 after operation with a significant difference. The rate of excellent and good curative effects was 93.8%.CONCLUSION: The titanium-coated cage used in PLIF to treat lumbar instability can achieve good immediate stability after operation.

BACKGROUND: At present, Doppler tissue imaging can be used extensively to make a quantitative assessment of left ventricular regional myocardial function. Postsystolic shortening is a delayed relaxation in regional myocardium following acute ischemia.OBJECTIVE: To observe longitudinal wall motion characteristics in left ventricular regional myocardiun and evaluate the clinical significance of postsystolic shortening in isovolumic relaxation period.DESIGN: Case-control observation.SETTING: Heart Center of Beijing Chaoyang Hospital.PARTICIPANTS: We selected 30 myocardial infarction inpatients hospitalized in the Heart Center of Beijing Chaoyang Hospital between April 2003 and September 2003 as myocardial infarction group; another 30 patients with non-cardiac diseases were set as control group. Subjects of the two groups volunteered in the experiment.METHODS: Dynamic images were collected and information was analyzed off-line. Left ventricular myocardial velocity and time velocity integral profiles were acquired along long axis asynchronously in basal and mid- segments of different walls. Peak velocity of isovolumic contraction period (VIC), ejection period (Ye), isovolumie relaxation period (VIR), rapid filling period (VRF) and atrial systole (VAS) and maximum time velocity integral (TVIMAX) in regional myocardium were measured.Doppler in different segments at longitudinal wall of myocardium in the the two groups.RESULTS: Thirty patients were recruited in myocardial infarction group and control group separately and all of them entered the result analysis ocardium was lower in myocardial infarction group than in control group,especially in infarcted segments, suggesting that the function of cardiac contraction and relaxation in patients with myocardial infarction was demyocardial isovolumic relaxation in myocardial infarction group, indicating period and isovolumic relaxation period in TVIMAX in myocardial infarction group.mal movement at isovolumic relaxation phase suggests the presence of postsystolic shortening and abnormal wall motion in regional myocardium.chemic myocardium.

BACKGROUND:Polyester fabric as a common clinical consumable item is characterized by simple drawing, low cost, and high toughness and ductility, and can serve as a good repair material. OBJECTIVE:To investigate the clinical efficacy of polyester fabrics used for huge chest wal repair. METHODS: Totaly 46 patients with chest wal tumors, aged 39-73 years, including 29 males and 17 females. These patients were randomly and equaly divided into observation group and control group. After the removal of chest wal tumors, patients in the observation group underwent polyester fabric repair of huge chest wal defects, and those in the control group were treated with autologous pedicle flap for repair of huge chest wal defects. The clinical efficacy and patient satisfaction were recorded in the two groups. RESULTS AND CONCLUSION: After treatment, al the patients could feel up to their daily work, and there were no death and serious complications. Only two cases developed postoperative local effusion, and then recovered after wound drainage. Thoracic appearance was good in al patients, and the patients did not feel discomfort at the reconstruction site during breathing and movement. At the end of 6-24 months of folow-up, X-ray review showed good reconstruction of the thorax, and there were no loose transplants, foreign body rejection, chest wal deformity, recurrence and serious complications. Clinical efficacy and patient satisfaction were better in theobservation group than the control group (P < 0.05). These results show that polyester fabrics for the repair of huge chest wal defects are effectively, safe and reliable.