Preliminary study on the suitability of a pharmacological bio-assay based on cardiac myocytes cultured over microfabricated microelectrode arrays

There are a range of techniques that can be used to assay bioactive compound. One potentially promising technique is a system consisting of microfabricated extracellular recording devices over which electrogenic cells can be grown. To date, research in this area has concentrated on the use of neurons as an electrogenic cell type. However, these cells have limitations. Only small extracellular potentials have been recorded from mammalian neurons cultured over microfabricated electrode arrays. Although such potentials may be of use in assays examining the effects of bio-active compound analogues on firing frequency, they are of little use for more detailed pharmacological studies involving analyses of signal shape. What is required is a system from which much larger extracellular potentials can be recorded. This preliminary study reports on a system based on cardiac myocytes cultured over microfabricated metal microelectrode arrays, from which potentials with a mean amplitude of 16.9 μV can be reliably recorded, which can be reversibly blocked with μmoll⁻¹ concentrations of the sodium ion channel blocker lidocaine. Less common potentials with amplitudes of up to 3.5 mV were also recorded. It is demonstrated that cardiac myocytes cultured over microfabricated micro-electrode arrays can be used in assays of cardioactive compound analogues.     

芬太尼对离体大鼠心脏收缩力及心肌细胞钙离子移动的影响

目的　观察芬太尼对离体灌流心脏收缩力及心肌细胞钙离子移动的影响,研究其对心肌收缩力的作用。方法　（１） 以含不同浓度芬太尼的克汉二氏重碳酸盐缓冲液（ＫＨＢ） 灌流大鼠心脏,测定心率（ＨＲ） 、左室收缩压（ＬＶＳＰ） 、左室舒张压（ＬＶＤＰ）、左室收缩压上升最大速率（ ＋ ｄｐ／ｄｔｍａｘ）、左室舒张压下降最大速率（ － ｄｐ／ｄｔｍａｘ） ;（２） 用Ｆｌｕｏ３ＡＭ 钙荧光指示剂染色急性分离的大鼠心肌细胞,在激光共聚焦显微镜下动态观察用药前和用不同浓度芬太尼后,ＫＣｌ 诱发的细胞内钙离子浓度的变化。结果　１ ｎｇ／ｍｌ 和２０ ｎｇ／ｍｌ 的芬太尼对心肌收缩力和心肌细胞钙离子移动的影响较小,心肌收缩力的各项指标和钙荧光强度与对照组相比,差异无显著性（ Ｐ＞ ０．０５） 。而２００ ｎｇ／ｍｌ 芬太尼使心率减慢及＋ ｄｐ／ｄｔｍａｘ 、－ ｄｐ／ｄｔｍａｘ下降,且差异有显著性（ Ｐ＜０ ．０５） 。结论　芬太尼对心肌细胞钙离子的跨膜内流影响较小,而使心肌收缩力保持稳定。超临床使用浓度的芬太尼仍有抑制心肌的趋势。     

The Wolff-Parkinson-White syndrome: the cellular substrate for conduction in the accessory atrioventricular pathway

The longstanding quest for the anatomical basis of the Wolff-Parkinson-White syndrome has left many unanswered questions. The ultrastructuralmorphology of the myocytes comprising accessory atrioventricularpathways, which are capable of rapid and variable conduction,is central to understanding the development and behaviour ofthis congenital anomaly, but remains unknown. Examination ofthree surgically resected pathways was performed to determinetheir underlying cellular morphology and the pattern of intercellularcoupling, by correlative light microscopy, electron microscopyand confocal scanning laser microscopy combined with immunohistochemicallocalization of the cardiac gap-junctional protein, connexin43. Two left-sided pathways were composed of myocardium of ‘normalworking ventricular’ type. The right-sided pathway wascomposed almost entirely of highly abnormal myocytes characterizedby aberrant myofibril organisation, with a lack of A-band materialand abnormal mitochondria, but normal intact intercalated disksno different from those seen in left-sided pathways. The gapjunctions of all pathways were composed of connexin43 distributedas in ventricular myocardium, and not as found in atrial oratrioventricular nodal tissues. While myocytes of abnormal structure were present in one ofthe accessory atrioventricular pathways examined, all pathwayshad morphologically normal gap junctions, the structures responsiblefor efficient intercellular coupling, with a pattern of distributionsuggestive of working ventricular myocardium.     

参麦注射液对缺血大鼠心肌内钙超载的影响

目的：观察参麦注射液对大鼠缺血心肌细胞内钙超载的影响及其心肌保护作用。方法：用异丙肾上腺素制备大鼠心肌缺血模型,Ｆｕｒａ－２ 法测定大鼠红细胞胞浆游离钙浓度（ＥｒｙＣａｉ）;生化法测定红细胞膜钙泵（Ｃａ－ｐｕｍ ｐ）、钠泵（Ｎａ－ｐｕｍ ｐ）活性,同步观察大鼠心肌组织病理变化。结果：参麦注射液治疗后ＥｒｙＣａｉ较缺血组显著降低（１．６８±０．１０ Ｆ３３５／Ｆ３８５ ｖｓ１．５６±０．１５ Ｆ３３５／Ｆ３８５ Ｐ＜ ０．０５）,但仍高于对照组（１．５６±０．１５ Ｆ３３５／Ｆ３８５ ｖｓ１．３６±０．１０Ｆ３３５／Ｆ３８５ Ｐ＜ ０．００１）;钙泵（１０５．１±２９．４ μｍ ｏｌＰｉ·ｇＨｂ－ １ ·２ｈ－ １ｖｓ １２６．８±３０．７ μｍ ｏｌＰｉ·ｇＨｂ－ １ ·２ｈ－ １ Ｐ＞ ０．０５）及钠泵（３５．１±１８．２ μｍ ｏｌＰｉ·ｇＨｂ－ １·２ｈ－ １ ｖｓ ４３．３±１０．２ μｍ ｏｌＰｉ·ｇＨｂ－ １·２ｈ－ １ Ｐ＞ ０．０５）活性较缺血组有所增高,但无统计学意义,且钙泵（１２６．８±３０．７ μｍ ｏｌＰｉ·ｇＨｂ－ １ ·２ｈ－ １ ｖｓ １６８．６±３９．６ μｍ ｏｌＰｉ·ｇＨｂ－ １ ·２ｈ－ １ Ｐ＜ ０．０１）及钠泵（４３     

西红花酸对去甲肾上腺素所致原代培养心肌细胞能量代谢和凋亡的影响

目的研究西红花酸对去甲肾上腺素(NE)诱导原代培养心肌细胞能量代谢障碍和细胞凋亡的保护作用。方法1 μmol·L^-1 NE损伤原代培养的心肌细胞,检测细胞培养上清液的LDH、心肌细胞ATPase、线粒体琥珀酸脱氢酶(MSDH)的活力,线粒体膜电位的变化,流式细胞仪检测细胞凋亡,观察西红花酸保护作用。结果模型组细胞培养上清液LDH增加,心肌细胞MSDH和ATPase的活力降低,线粒体膜电位降低,心肌细胞凋亡率增加。西红花酸明显降低培养上清液LDH增加,提高MSDH和ATPase的活力、线粒体膜电位的水平,对心肌细胞的凋亡具有明显的保护作用。结论西红花酸对NE所致的心肌细胞能量代谢障碍和凋亡具有明显的保护作用。     

中药预处理对家兔缺血再灌注损伤心肌细胞凋亡的影响

目的观察中药复方温心汤对家兔心肌缺血再灌注损伤心肌细胞凋亡以及病理组织学改变的影响.方法采用实验性家兔缺血再灌注及缺血预适应模型,随机分成7组,每组8只.观察各组家兔血清心肌酶学变化,并通过电镜形态学及原位末端标记法检测心肌细胞凋亡情况.结果缺血预适应和温心汤预处理组心肌酶水平与缺血再灌注组、复方丹参和消心痛组相比差异显著(P<0.01);缺血预适应和温心汤预处理组心肌细胞凋亡率与缺血再灌注组、复方丹参和消心痛组相比差异显著(P<0.05).结论缺血预适应和中药复方温心汤预处理可减轻心肌细胞损伤,很大程度上是通过减轻心肌细胞凋亡而起作用的,提示温心汤对实验性家兔心肌缺血再灌注损伤的保护作用可能是通过预处理的途径产生的.     

大蒜素对大鼠心室肌细胞L-型钙通道的影响

目的:探讨大蒜素对大鼠心室肌细胞L-型钙通道的作用.方法:用急性酶解法获得大鼠的单个心肌细胞,用标准的全细胞膜片钳技术记录钙通道电流.结果:5、50、250和500μmol/L大蒜素分别抑制钙电流4.4%、26.91%、38.06%、72.90%.250μmol/L大蒜素能使心肌细胞钙电流-电压曲线明显上移,峰电流密度从(7.17±0.65)pA/pF减少至(4.44±0.52)pA/pF(n=15,P<0.05),但激活电位、峰电位和翻转电位无明显改变(P>0.05).大蒜素能使钙电流失活曲线明显左移(P<0.05).大蒜素对钙电流激活曲线、失活再复活曲线和频率依赖性无明显影响(P>0.05).结论:大蒜素呈浓度依赖性地抑制心肌细胞L-型钙通道.     

碘化N-正丁基氟哌啶醇对豚鼠心房肌细胞乙酰胆碱敏感性钾通道的影响

目的研究碘化N正丁基氟哌啶醇(F2)对豚鼠心房肌细胞乙酰胆碱敏感性钾通道(KACh)的影响,探讨其对KACh的作用机制。方法采用膜片钳全细胞记录方法,测定F2对原代培养的豚鼠心房肌细胞乙酰胆碱敏感性钾电流IK(ACh)的影响。结果细胞外给予F2对豚鼠心房肌细胞IK(ACh)呈可逆性、浓度依赖性的阻断作用。细胞内添入抗水解的GTP类似物GTPγS后,结果同前。细胞内给予50μmol·L-1F2对IK(ACh)无作用。结论F2是豚鼠心房肌细胞KACh的一种快速通道阻断剂,发挥作用部位在细胞膜外侧,作用位点在钾通道本身,与乙酰胆碱受体无关。     

髓母细胞瘤组织MEF2C表达与预后相关性分析

目的：探讨肌细胞增强因子2C（myoeyte enhancer factor2C，MEF2C）表达情况与髓母细胞瘤患者预后的关系。方法：选取3家三级甲等医院2001-01—01—2007—12-31病理确诊的髓母细胞瘤患者56例，其中泰安市中心医院12例．齐鲁医院26例，山东省立医院18例；对照组脑组织取自泰安市中心医院2010-01-01-2010—12—3112例非肿瘤脑外伤患者。免疫组织化学法检测56例髓母细胞瘤患者肿瘤组织和12例非肿瘤患者脑组织中MEF2C的表达；收集髓母细胞瘤患者临床资料，应用统计学方法对髓母细胞瘤患者进行生存分析。结果：髓母细胞瘤患者肿瘤组织MEF2C相对高表达率为53．6％（30／56），非肿瘤患者脑组织MEF2C相对高表达率为0（0／12），两组比较差异有统计学意义，χ2=11．50，P=0．001；肿瘤患者肿瘤组织MEF2C相对高表达组与相对低表达组间生存时间的差异有统计学意义，χ2=4．34，P=0．037。MEF2C相对高表达（p=0．023）、肿瘤转移（P=0．042）与患者3年生存率降低显著有关，而患者性别、年龄、肿瘤大小、肿瘤部位与患者3年生存率无关，P值均〉0．05。结论：MEF2C在患者肿瘤组织中的高表达可降低患者3年生存率，是患者预后不良的危险因素之一。     

Ultrasonic Cavitation-Enabled Treatment for Therapy of Hypertrophic Cardiomyopathy: Proof of Principle

Ultrasound myocardial cavitation-enabled treatment was applied to the SS-16^BN rat model of hypertrophic cardiomyopathy for proof of the principle underlying myocardial reduction therapy. A focused ultrasound transducer was targeted using 10-MHz imaging (10 S, GE Vivid 7) to the left ventricular wall of anesthetized rats in a warmed water bath. Pulse bursts of 4-MPa peak rarefactional pressure amplitude were intermittently triggered 1:8 heartbeats during a 10-min infusion of a microbubble suspension. Methylprednisolone was given to reduce initial inflammation, and Losartan was given to reduce fibrosis in the healing tissue. At 28 d post therapy, myocardial cavitation-enabled treatment significantly reduced the targeted wall thickness by 16.2% (p?<0.01) relative to shams, with myocardial strain rate and endocardial displacement reduced by 34% and 29%, respectively, which are sufficient for therapeutic treatment. Premature electrocardiogram complexes and plasma troponin measurements were found to identify optimal and suboptimal treatment cohorts and would aid in achieving the desired impact. With clinical translation, myocardial cavitation-enabled treatment should fill the need for a new non-invasive hypertrophic cardiomyopathy therapy option.