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1.
The possibility of rats mesenchymal stem cells (MSCs) modified with murine hyperpolarization-activated cyclic nucleotide-gated 2 (mHCN2) gene as biological pacemakers in vitro was studied. The cultured MSCs were transfected with pIRES2-EGFP plasmid carrying enhanced green fluorescent protein (EGFP) gene and mHCN2 gene. The identification using restriction enzyme and sequencing indicated that the mHCN2 gene was inserted to the pIRES2-EGFP. Green fluorescence could be seen in MSCs after transfection for 24-48...  相似文献   

2.
摘要:目的探讨血管活性肽内皮素-1(ET-1)对新生鼠心室肌细胞起搏通道If表达的影响及其细胞内信号机制。方法采用酶消
化法急性分离1~3 d龄新生大鼠心室肌细胞,用全细胞膜片钳技术记录If电流,定量RT-PCR技术检测介导If电流的、超极化激活
的环核苷酸门控通道亚型HCN2 和HCN4 的表达。结果ET-1 呈剂量和时间依赖性增强了HCN2 和HCN4 通道亚型的表达,
ET-1的这一作用可被其ETA受体阻断剂BQ-123阻断,而非ETB受体阻断剂BQ-788,而且特异性p38 MAPK抑制剂SB-203580
也不影响ET-1的作用。结论ET-1通过一种ETA受体介导的、不依赖于p38 MAPK的信号转导机制刺激了心肌细胞起搏通道If
的表达。这一作用与ET-1致心律失常机制有关。
  相似文献   

3.
目的:通过分析风湿性心脏病二尖瓣狭窄(风心二狭)患者心房肌组织HCN4基因表达及动作电位与心房颤动发生的关系,为风心二狭房颤发生机制的研究提供理论依据。方法:取手术患者心耳组织100mg,提取RNA后应用半定量逆转录-PCR方法检测mRNA含量,并对PCR产物测序分析;以HCN4基因mRNA和内参β-actin含量的比值作为评价HCN4基因mRNA表达水平指标;采用急性分离心肌细胞的方法将其分为MS房颤(atrial fibrillation,AF)组和窦律(Sinus rhythm,SR)组,记录两组的动作电位(AP),观察两组心肌细胞动作电位时程(APD)的改变。结果:风心二狭房颤组及对照组HCN4基因mRNA与β-actin含量的相对表达值比值分别为0.696±0.257和0.125±0.010,两组比较,差异有统计学意义(P<0.01)。房颤病人心房肌APD、APD复极至50%的时程(APD50)及APD复极至90%的时程(APD90)较窦性心律组明显缩短,差异有统计学意义(P<0.05)。结论:房颤心肌细胞HCN4基因的过度转录表达及APD缩短可能共同参与了调控风心二狭房颤的发生过程,揭示了风心二狭房颤发生的分子机制及电流学机制。  相似文献   

4.
Sun G  Li M  Li GY  Ding J  Li SH 《中华医学杂志》2011,91(1):5-10
目的 探讨320排容积CT(DVCT)冠状动脉血管成像患者心率,重组时相与图像质量的关系.方法 对2008年12月至2009年7月在济南军区总医院接受DVCT 80例患者行回顾性分析,其中男43例、女37例,年龄34~79(64±8)岁.以10%为间期,重建10%~100%R-R间期各时相图像.2位阅片者以图像质量1级(无运动伪影)至4级(严重伪影)对3支主要冠状动脉(右冠状动脉、前降支及左旋支)进行评价.分析心率对图像质量及收缩期/舒张期比例的影响;评价最佳重建时相与心率的关系.结果 平均扫描心率为47~128(71±15)次/min.随着心率的增加,3支冠状动脉平均图像质量评分呈线性增加(y=-0.154+0.022x,t=11.0,P<0.01).在心率<98次/min时,即可得到1、2级图像.收缩期/舒张期比例随心率的增加而增加(t=10.8,P<0.01),同时随着心率的增加,收缩期及舒张期最佳重建期相均向后推移.当心率>93次/min时最佳图像重建时相由舒张期转为收缩期.结论 DVCT可在更宽心率范围内获得优良冠状动脉图像;对DVCT不同心率最佳重建时相的研究,有助于获得优良图像质量,减少患者吸收剂量.
Abstract:
Objective To investigate the impact of hart rate (HR) and reconstruction timing on image quality by a 320-detector row dynamic volume CT system (DVCT). Methods A total of 80 patients were examined by DVCT angiography. There were 43 males and 37 females with a mean age of 64 ± 8 years old. The heart rate (HR) was 47 - 128 beats per minute. The data were reconstructed by 10% steps throughout the R-R interval. And the data sets were evaluated by 2 independent readers for each major coronary vessel, namely right coronary artery, left anterior descending artery and left circumflex artery. The motion score for each vessel was graded from 1 ( no motion artifacts) to 4 ( severe motion artifacts over an entire vessel). The HR dependency of image quality was determined by an analysis of linear regression. The linear regression between HR and the optimal image quality in diastole or systole was also calculated.Results The average HR was 71 ± 15 beats per minute. And the image quality was significantly affected by HR (y = -0.154 +0. 022x, t = 11.0, P <0.01 ). According to this equation, images of grades 1 and 2 could be achieved at HR <98 beats per minute. The proportion of systole was influenced by HR statistically (t = 10.84, P<0.01 ). With the increase of HR, the optimal systolic and diastolic reconstruction intervals all shifted to the later phases. The cut-off heart rate at which optimal reconstruction interval turned from diastole to systole was 93 bpm. Conclusion Coronary DVCT angiography provides quality diagnostic images within a wide range of heart rates. And the study of optimal reconstruction interval will help to reduce the imaging artifacts and lower the patient absorption dose.  相似文献   

5.
Background Shen song Yang xin (SSYX) is a compound of Chinese medicine with the effect of increasing heart rate (HR). This study aimed to evaluate its electrophysiological properties at heart and cellular levels. Methods The Chinese miniature swines were randomly assigned to two groups, administered with SSYX or placebo for 4 weeks (n=8 per group). Cardiac electrophysiological study (EPS) was performed before and after drug administration. The guinea pig ventricular myocytes were enzymatically isolated and whole cell voltage-clamp technique was used to evaluate the effect of SSYX on cardiac action potential (AP). Results SSYX treatment accelerated the HR from (141.8±36.0) beats per minute to (163.0±38.0) beats per minute (P=0.013) without changing the other parameters in surface electrocardiogram. After blockage of the autonomic nervous system with metoprolol and atropin, SSYX had no effect on intrinsic HR (IHR), but decreased corrected sinus node recovery time (CSNRT) and sinus atrium conducting time (SACT). Intra cardiac EPS showed that SSYX significantly decreased the A-H and A-V intervals as well as shortened the atrial (A), atrioventricular node (AVN) and ventricular (V) effective refractory period (ERP). In isolated guinea pig ventricular myocytes, the most obvious effect of SSYX on action potential was a shortening of the action potential duration (APD) without change in shape of action potential. The shortening rates of APD30, APD50 and APD9o were 19.5%, 17.8% and 15.3%, respectively. The resting potential (Em) and the interval between the end of APD30 and APD90 did not significantly change. Conclusions The present study demonstrates that SSYX increases the HR and enhances the conducting capacity of the heart in the condition of the intact autonomic nervous system. SSYX homogenously decreases the ERP of the heart and shortens the APD of the myocytes, suggesting its antiarrhythmic effect without proarrhythmia.  相似文献   

6.
目的 通过检测新生大鼠心室肌细胞在给予药物决奈达隆前后超极化激活环核苷酸门控阳离子通道(HCN通道)mRNA和蛋白水平的变化,探讨决奈达隆对HCN通道表达的影响.方法 分离新生SD大鼠心室肌,Ⅱ型胶原酶消化,通过差速贴壁分离法收集获得单一的心室肌细胞.并根据浓度(0.1、0.5、1.0、5.0、10.0、20.0μmol/L的决奈达隆对细胞进行处理48h)和时间(浓度为10 μmol/L的决奈达隆对细胞进行1、6、12、24、48 h的处理)梯度分组.采用实时荧光定量PCR法和Western blot检测HCN2、HCN4通道mRNA水平和蛋白水平.结果 浓度梯度组和时间梯度组的HCN2 mRNA和HCN4 mRNA表达水平均低于对照组(P<0.05);与对照组比较,10 μmol/L决奈达隆处理后12 h组的蛋白水平明显下调(P<0.01).结论 决奈达隆可抑制HCN2、HCN4通道mRNA和蛋白的表达,且作用呈浓度依赖性,在给药后12 h达到最大作用.  相似文献   

7.
目的探讨不同心率在640层螺旋CT冠状动脉CTCA中对血管图像质量的影响以及辐射剂量变化。方法选取91例患者,男性51例,女性40例,平均年龄58岁。分成三组,A组30例,心率≤65次/分;B组30例,65次/分心率≤80次/分;C组31例,心率80次/分。扫描完成后选取最佳时相进行容积再现(VR)、最大密度投影(MIP)、多平面重建(MPR)及曲面重建(CPR)进行血管重建,根据4分法对血管图像质量分级并进行统计学分析,记录各组的辐射剂量程度乘积(DLP)。结果三组的血管图像质量在可评价比例及优良率无统计学意义,心率与血管图像质量等级呈负相关。A组DLP为(3.37±2.12)m Gy.cm,B组为(4.78±1.92)m Gy.cm,C组为(6.11±2.79)m Gy.cm,三组的辐射剂量有差异,经检验,有统计学意义,心率与辐射剂量呈正相关。结论 640层螺旋CT冠状动脉CTCA在高心率患者能较好的显示图像,同时辐射剂量也增加,应该在情况允许的条件下尽可能降低心率至65次/分以下,在获得优良血管图像质量的同时降低辐射剂量,有利于冠状动脉CTCA的可持续发展,以便让更多患者从中获益。  相似文献   

8.
Li JW  Guo JH  Zhang P  Li C  Liu YW  Zhou CY 《中华医学杂志》2006,86(19):1332-1336
目的观察过度表达超极化激活环核苷酸门控阳离子通道基因亚型(HCN)4对乳鼠心肌细胞电生理特性的影响。方法酶解法分离20只乳鼠的原代心肌细胞并进行培养,用含HCN4基因的重组腺病毒AdHCN4感染心肌细胞,以未感染细胞作为对照组,通过RT-PCR及细胞免疫荧光方法检测心肌细胞中HCN4基因在mRNA和蛋白质水平的表达,用全细胞膜片钳方法测定转染HCN4基因的心肌细胞的动作电位和起搏电流If。结果AdHCN4感染组心肌细胞中HCN4mRNA和蛋白质的表达水平明显高于对照组细胞;感染组心肌细胞自发搏动的频率为(92·5±7·4)次/分,明显高于对照组心肌细胞的(68·9±6·2)次/分(P<0·05);动作电位出现明显的4相自动除极化,其最大舒张电位(-52·8±4·2)mV明显高于对照组细胞(-62·1±2·6)mV(P<0·05);动作电位复极50%和90%的时间两者比较差异无统计学意义;在感染组细胞中,起搏电流If的电流密度为(115·7±7·8)pA/pF,也明显高于对照组细胞的(7·2±0·6)pA/pF(P<0·05)。结论过度表达起搏通道基因HCN4能够明显增强乳鼠心肌细胞的自律性,从而增加心肌细胞自发搏动的频率,这提示HCN4基因有可能成为治疗缓慢性心律失常疾病的目的基因。  相似文献   

9.
目的:研究重组腺病毒(Ad)对骨髓基质干细胞(MSCs)的转染,以及绿色荧光蛋白(GFP)和成肌调节因子MyoD和Myogenin在MSCs中的表达. 方法:用差速贴壁法体外培养大鼠MSCs,并用流式细胞仪(FCM)检测其表面标志;对构建有绿色荧光蛋白的重组腺病毒(Ad-GFP)进行扩增和鉴定,并转染MSCs;用RT-PCR检测MyoD和Myogenin在转染后MSCs中的表达;将MSCs与C2C12成肌细胞共培养,诱导前者的分化,并用免疫荧光检测MyoD的表达. 结果:FCM检测证实,在MSCs的表面标志中CD11b和CD45阴性,而CD29和CD44阳性;随着Ad-GFP感染复数(MOI)的增加,转染效率也相应提高,但在MOI大于100后,MSCs开始出现病变;RT-PCR结果提示MyoD和Myogenin在转染后的MSCs中有表达;免疫荧光检测证实诱导后的MSCs可以表达MyoD蛋白. 结论:MSCs可以被Ad-GFP有效转染而表达GFP;同时内源性成肌调节因子的激活,可以促进MSCs的成肌分化.  相似文献   

10.
目的: 研究锌指转录因子(GATA4)基因修饰骨髓间充质干细胞(MSCs)对心肌梗死大鼠心功能的影响,为进一步探讨其机制提供依据。方法: 构建GATA4-pEGFP基因质粒,体外分离培养大鼠MSCs,利用脂质体将质粒转染入MSCs。40只SD大鼠制备大鼠心肌梗死模型,于术后10 d测定心功能指标。将模型鼠随机分为MSCs 组和DMEM组,每组各20只。MSCs 组将GATA4-pEGFP基因修饰的MSCs植入心肌梗死后10 d大鼠心肌梗死区,DMEM组同时注射等体积无血清DMEM于心肌梗死区。移植注射后4周,检测左心室射血分数(LEVF)和左室缩短分数(FS)。结果: 体外分离培养的MSCs呈梭形或条形,贴壁生长 。 GATA4-pEGFP重组基因质粒转染MSCs 2周后,可见细胞中有绿色荧光蛋白表达。移植4周后,MSCs组大鼠LEVF(85%±7%)明显高于DMEM组(47%±4%)(P<0.01); MSCs组大鼠FS(52%±6%)明显高于DMEM组(35%±8%)(P<0.01)。结论: GATA4基因修饰的MSCs移植能够改善心肌梗死大鼠心功能。  相似文献   

11.
目的:构建携带间隙连接蛋白connexin43(Cx43)cDNA的真核表达载体,转染骨髓基质干细胞,观察间隙连接蛋白Cx43在骨髓基质干细胞中的过量表达.方法:目的基因Cx43 cDNA在大肠杆菌中扩增后连入真核表达载体pcDNA3.0,转染大鼠骨髓基质干细胞,用G418筛选得到Cx43基因高表达的细胞;对照组为pcDNA3.0直接转染骨髓基质干细胞.结果:酶切电泳结果显示按设计构建的载体pcDNA3.0-Cx43,经G418筛选得到不同抗性的骨髓基质干细胞,免疫细胞化学显示有Cx43蛋白的表达.结论:Cx43可以在骨髓基质干细胞中表达.  相似文献   

12.
窦房结细胞自律性与超极化激活起搏电流关系的研究进展   总被引:1,自引:0,他引:1  
汪艳丽 《医学综述》2011,17(12):1778-1780
窦房结是正常心脏活动的起搏点,在心脏传导系统中自律性最高,窦房结细胞的自动除极是其自律性产生的基础,多种离子通道及相应电流参与窦房结细胞自律性活动,其中超极化激活环核苷酸门控通道(HCN)及其电流(If)在窦房结细胞自律性产生过程中起着重要作用,HCN通道共有HCN1~4四个亚型,在心脏窦房结细胞中HCN4是主要的亚型,负责形成If,HCN4及相关If对窦房结自律性有着重要的影响。  相似文献   

13.
目的 :探讨体外“心肌样”环境对骨髓基质细胞 (marrowstromalcells ,MSCs)分化的诱导作用。方法 :体外将MSCs与心肌细胞共培养至 16d ,用数码显微摄像及免疫荧光技术分别记录和检测被标记MSCs的生长行为和心肌特异性肌节肌球蛋白重链 (cardiacmyosinheavychainα/ β ,MHCα/ β)、肌钙蛋白I(troponinI,TnI)的表达 ;并在同等条件下 ,与用心肌条件培养基及正常培养基培养的MSCs进行比较。结果 :正常培养基组与条件培养基组均未发现MSCs分化为心肌细胞的可靠证据。但在共培养组 ,观察到了搏动的MSCs;MHCα/ β与ThI蛋白分别于第 1,4d开始表达 ,随时间延长 ,表达阳性MSCs增多。结论 :体外MSCs与心肌细胞接触生长可向心肌细胞分化。  相似文献   

14.
Background Mutations in the lamin A/C gene (LMNA) may cause familial dilated cardiomyopathy (dilated cardiomyopathy) characterized by early onset atrio-ventricular block (A-V block) before the manifestation of dilated cardiomyopathy and high risk of sudden death due to ventricular arrhythmia, which is very similar to the phenotype of gap junction related heart disease. This study aimed to determine the expression and localization of connexins in neonatal myocytes transfected with wild-type (WT) or mutant LMNA to elucidate how these mutations cause heart diseases. Methods We studied the connexin 43 (Cx43) and connexin 40 (Cx40) expression in cultured neonatal myocytes transfected with wild-type (WT) or mutant LMNA (Glu82Lys (E82K) and Arg644Cys (R644C)) using confocal imaging and Western blotting analysis. Results Cx43 protein expression was reduced by 40% in cells transfected with LMNA E82K than that in cells transfected with WT LMNA cDNA. Confocal imaging showed that the Cx43 located inside the cells by LMNA E82K. By contrast, LMNA E82K mutation had no effect on expression and localization of Cx40. LMNA R644C transfection did not show any significant effects on gap junctions at all. Conclusions Our findings suggest that LMNA E82K significantly reduced the Cx43 expression and altered its localization which may be one of the pathological mechanisms underlying LMNA-related heart disease.  相似文献   

15.
目的:观察17β-雌二醇(17β-E2)对大鼠骨髓间充质干细胞(MSCs)成骨分化过程中钙离子(Ca2+)通道的影响,阐明17β-E2对MSCs促成骨分化的作用机制。方法:采用密度梯度离心法和贴壁筛选法分离出MSCs,连续传代3次,进行成骨细胞的诱导分化。将MSCs分为对照组[单纯成骨细胞培养基(OBM)培养]和不同剂量17β-E2组(在OBM中分别添加0.1、1.0、10.0和100.0 pmol·L-1 17β-E2)。成骨诱导14 d,各组细胞经Fluo-3/AM染色后,利用激光扫描共聚焦显微镜测定平均荧光强度(MFI),以MFI代表Ca2+水平。应用全细胞膜片钳技术记录不同条件下的全细胞Ca2+电流。结果:采用密度梯度离心法和贴壁筛选法成功分离MSCs。MSCs细胞呈成纤维细胞样,核呈椭圆形,细胞核内可见核仁。传代培养的MSCs生长旺盛,保持原代细胞的形态特征。随着17β-E2浓度的增加,各组细胞的Ca2+水平也逐渐增强,以100.0 pmol·L-1 17β-E2组最为明显。与对照组比较,10.0和100.0 pmol·L-1 17β-E2组的MSCs成骨分化过程中Ca2+水平和Ca2+电流峰值明显升高(P<0.05或P<0.01),0.1和1.0 pmol·L-1 17β-E2组Ca2+水平和Ca2+电流峰值差异无统计学意义(P>0.05)。结论:密度梯度离心法和贴壁筛选法分离所得细胞为大鼠MSCs。17β-E2通过增强MSCs Ca2+通道的开放,增强Ca2+内向电流发挥促进成骨形成作用,并呈剂量依赖性。  相似文献   

16.
移植的间充质干细胞与宿主心肌匹配整合实验研究   总被引:2,自引:1,他引:1  
目的 探索间充质干细胞(MSCs)分化的心肌样细胞与宿主心肌匹配的解剖结构基础.方法 采用成年近交系Wistar大鼠,经左冠状动脉前降支结扎1 h建立心肌缺血再灌模型.术后1周,将来自同种供体、经体外扩增和Rt-GFP转染MSCs后植入梗死区.移植后4周测定心脏功能.随后取材、连续冰冻切片,观察心肌组织形态学的变化及MSCs分化的心肌样细胞缝隙连接(Connexin-43)的表达.结果 植入梗死区中的MSCs表达Connexin-43.移植组梗死区面积缩小,左心室壁厚度增加,心脏功能改善.结论 移植的MSCs通过分化为心肌样细胞,并与宿主心肌细胞形成电机械匹配结构即缝隙连接(Connexin-43),使新增加的心肌细胞能够与宿主心肌同步收缩,从而更有效改善心脏功能.  相似文献   

17.
目的比较起搏器置入患者行640层容积CT与64层螺旋CT冠状动脉造影的图像质量和伪影,探讨CT冠状动脉造影的成功率和适用性。方法 24例拟行CT冠状动脉造影的起搏器置入病例根据使用设备的不同分为A组(640层CT组)与B组(64层CT组)两组,请两位有经验的评价者双盲评价冠脉15个节段的图像质量以及各种伪影对冠脉节段的影响,同时记录辐射剂量和患者一般资料,并进行统计分析。结果两组之间的身高、体重等一般影响因素均无统计学差异。尽管A组的心率显著高于B组(A组的心率:71±16次/分;B组的心率:61±4次/分;P<0.001),但A组的辐射剂量显著低于B组(A组的ED:13.8±1.53 mSv;B组的ED:9.14±5.65 mSv;P<0.001)。在起搏器置入患者冠状动脉图像可诊断率(1级+2级)的比较上,A组与B组间有统计差异(A组:99.06%,B组:93.27%,连续校正χ2=6.572,P<0.05)。影响两组冠状动脉图像质量的伪影有运动伪影、阶梯伪影、金属伪影、数据缺失等,各种伪影对冠状动脉图像质量的影响程度两组间有统计学差异(连续校正χ2=5.009,P<0.05)。其中,A组的冠状动脉图像伪影以不影响诊断的轻度伪影为主,占94.3%,中重度伪影节段仅占伪影节段总数的5.78%,而B组的冠状动脉中重度伪影节段占伪影总数的31.8%。结论起搏器置入患者行CT冠状动脉造影时,640层容积CT与64层螺旋CT均能提供优秀的图像质量,但640层容积CT以较高的图像可诊断率和较轻的伪影干扰而比64层螺旋CT具有更高的成功率和适用性。  相似文献   

18.
Background Unstable bladder is one of the common clinical dysfunctions of the lower urinary tract. Gap junctions (GJs) are the plaques of aqueous channels that facilitate electrical and metabolic communication between the intracellular compartments of adjacent cells, exchange of nutrients and ions between connected cells and transfer of electrical signals In the present study we investigated the quantitative alterations of the GJ in the rat detrusor muscle and its functional changes related to the developing of unstable bladder (USB). Methods Thirteen female Wistar rats (study group) with obstructive unstable bladder as determined by urodynamic study and 10 sham-operated rats (control group) were sacrificed at 6 weeks after surgery. Cystometric investigation, and the content and distribution of the GJ protein connexin 43 (Cx43) in the detrusors which were taken from the bladder of the rats were studied by Western blot and laser confocal microscopy with a double label immunohistochemistry technique. Results The expression of Cx43 was found adjacent to the detrusor with the laser confocal microscopy. The Cx43 expression increased markedly in the study group (pixel density 29.5±13.9, staining size (17.9±8.8) μm2) compared with the control group (pixel density 14.2±2.2, staining size (5.7±3.1) pm2, P 〈0.05). Western blot analysis demonstrated that Cx43 in the study group (the average gray level was 31.066) was significantly higher than in the control group (the average gray level was 11.701, P 〈0.01 ). Conclusion The increase of GJ leading to a intercellular excitatory communication is one of the important mechanisms related to developing unstable bladder.  相似文献   

19.
超极化激活环核苷酸门控阳离子通道(HCN)在心脏起搏细胞中呈高表达,并参与心脏起搏的产生及心率调控。而调控该通道蛋白的基因突变、错义均可导致心律失常的发生。目前已发现5种HCN基因突变所致的心律失常,且存在家族遗传性。不仅如此,该基因在心肌不同的微环境中可能呈现出不同的表达,进一步影响心律的变化。现对HCN通道生物生理特点及HCN通道相关性疾病的研究进展进行综述。  相似文献   

20.
超极化激活环核苷酸门控通道(HCN)是目前基因治疗心律失常的研究热点。心脏生物起搏即利用生物学及其相关技术,修复或替代受损的自律性节律点和(或)特殊传导系统,使心脏的起搏和传导功能得以恢复。心脏生物起搏器应用于临床仍面临许多问题,但是随着分子生物学和基因工程技术的发展,心脏生物起搏器必将造福于人类。  相似文献   

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