急性心肌梗死晚期再灌注后心肌细胞凋亡与Bcl-2、Bax 蛋白表达的研究

目的:探讨犬急性心肌梗死后晚期再灌注对梗死周边缺血区心肌细胞凋亡及凋亡相关蛋白Bcl-2、Bax表达的影响。方法:健康成年杂交犬28只,全麻下常规开胸暴露冠状动脉后随机分为3组:假手术组(n=8),急性心肌梗死组(n=10)、晚期再灌注组(n=10)。假手术组仅行左冠状动脉前降支下穿过丝线而不结扎冠状动脉,急性心肌梗死组行左冠状动脉前降支高位永久结扎,晚期再灌注组在高位结扎左冠状动脉前降支6 h后松解结扎线予以再灌注6 h。共有23只犬模型制作成功。各组犬均于术后12 h处死,采集心肌标本。使用TUNEL法检测心肌细胞凋亡,免疫组化染色和Western blotting蛋白印迹分析Bcl-2、Bax在心肌细胞中表达情况。结果:晚期再灌注组心肌细胞凋亡数较急性心肌梗死组明显减少(P<0.05),但两组心肌细胞凋亡数均高于假手术组(P<0.01)。与假手术组相比,急性心肌梗死组和晚期再灌注组Bcl-2蛋白的表达均升高(P<0.01),其中在晚期再灌注组的表达略多于急性心肌梗死组,但无显著差异(P>0.05)。Bax蛋白在晚期再灌注组的表达高于假手术组(P<0.01),但低于急性心肌梗死组(P<0.05)。结论:急性心肌梗死后晚期再灌注可以减少梗死周边缺血区心肌细胞凋亡,其机制可能与心肌细胞表达Bax蛋白减少有关。     

粒细胞集落刺激因子促进大鼠梗死心肌修复

目的观察粒细胞集落刺激因子G(-CSF)对急性心肌梗死大鼠梗死区的修复和心功能的改善作用。方法29只大鼠随机分为细胞因子组(GAMI,n=9)、心肌梗死对照组(AMI,n=10)和假手术组(SO,n=10)。GAMI组和AMI组结扎左冠状动脉造成心肌梗死,SO组行相似的手术操作但不结扎冠状动脉。GAMI组给予rhG-CSF(50μg.kg-1.d-1),腹腔内注射,共7d。AMI组及SO组则每日腹腔内注射同等体积的生理盐水,共7d。心肌梗死后4周,通过心脏插管测量血流动力学参数,并在显微镜下观察梗死范围和梗死区、梗死周边区小血管数量的变化。结果AMI组大鼠有3只分别于术后第3、7、8天死亡,GAMI组与SO组大鼠至观察结束无一只死亡。与SO组相比较,AMI组LVSP(P<0.01)、dpd/tmax(P<0.01)、dpd/tmin(P<0.05)降低,LVEDP明显升高(P<0.01);GAMI组dpd/tmax(P<0.05)、LVEDP升高(P<0.01),LVSP、dpd/tmin无明显变化(P>0.05)。与AMI组相比较,GAMI组LVSP(P<0.01)、dpd/tmax(P<0.01)、dpd/tmin(P<0.05)升高,LVEDP降低(P<0.05)。与AMI组相比较,GAMI组梗死范围明显缩小(P<0.01),梗死区及梗死周边区小血管密度增加(P<0.05)。结论应用G-CSF可缩小心肌梗死大鼠梗死范围,提高梗死区及梗死周边区小血管密度并改善心功能。     

急性心肌梗塞心肌微血管的改变

以结扎家兔左冠状动脉左室枝的方法制作了急性心肌梗塞的动物模型,以双色素灌注制作透明标本和双色素微血管铸型的方法研究了急性心肌梗塞后心肌微血管的改变。正常心肌内的冠状动脉分枝为终末动脉;心肌的微循环单位是形态相同、大小相似的终末毛细血管管袢。急性心肌梗塞发生后24小时,梗塞部位心肌出现大面     

曲尼司特对大鼠心肌梗塞后心肌纤维化及TGF-β1表达的影响

目的观察曲尼司特对大鼠心肌梗塞(MI)后左室心肌纤维化(MF)和转化生长因子-β1(TGF-B1)表达的影响.方法结扎左冠状动脉前降支建立大鼠心肌梗塞模型,随机分成3组假手术组、MI模型组和曲尼司特治疗组(400 mg·kg1·d1).4周后测定血流动力学指标评价心功能,测量左心室重与体重之比、梗死面积、非梗死区心肌羟脯氨酸(HYP)含量和TGF-B1的表达.结果与MI模型组比较,曲尼司特治疗后心肌梗死面积无明显改变(P＞0.05),但左室功能显著改善(P＜0.05),左心室肥大减轻(P＜0.01),非梗死区心肌HYP含量和TGF-B1表达降低(P＜0.05).结论曲尼司特可下调大鼠非梗死区心肌TOF-β1表达及降低HYP含量,减轻MI后左室非梗死区心肌纤维化,改善心功能.     

犬急性心肌梗死模型的多层螺旋CT心肌灌注和冠状动脉造影

目的 :研究急性心肌缺血和梗死的多层螺旋CT(MSCT)心肌灌注特点 ,探索MSCT冠状动脉造影对冠状动脉阻断的显示情况。方法 :犬左冠状动脉前降支结扎前、后不同时期分别进行MSCT心肌灌注扫描 ,分析其特点 ,并与病理检查相对照 ;同时做MSCT冠状动脉造影观察冠状动脉阻断的情况。结果 :犬心肌正常灌注量为 ( 69.3±1 3 .9)ml·1 0 0g- 1·min- 1、达峰值时间 ( 1 2 .8± 2 .1 )sec。左冠状动脉前降支结扎 3 0min后MSCT心肌灌注表现为灌注量减低 ,时间密度曲线低平 ,延迟 1 0min扫描局部心肌密度无显著改变。结扎 4h后 ,局部心肌呈明显延迟增强。MSCT冠状动脉造影显示冠状动脉前降支中断。结论 :MSCT心肌灌注结合冠状动脉造影可以判断心肌缺血和梗死 ,同时显示冠状动脉的阻塞状况     

经冠脉移植骨髓单个核细胞对猪梗死心肌的修复作用

目的观察经冠脉移植骨髓单个核细胞的定植、分化和对心功能的影响。方法小型猪冠状动脉前降支结扎90min后再灌注制备心肌梗死模型,分为骨髓细胞移植组(BM-MNCs组,n=6)和对照组(n=5),分别经冠脉移植PKH26标记的骨髓单个核细胞和培养基,术后6周进行病理学检查并行血流动力学和超声心动图检查心功能变化。结果在BM-MNCs组,心肌梗死后6周在缺血心肌内可找到移植细胞,其Ⅷ因子和desmin免疫组化染色均为阳性;血流动力学指标显示左室等容舒张期压力最大变化率和心排量与心肌梗死后90min比较明显改善(P<0.05);超声心动图显示每搏输出量和心排量比对照组明显改善(P<0.05);心肌梗死边缘区的小血管数目明显多于对照组(P<0.05)。结论经冠脉移植骨髓单个核细胞可定植于梗死区心肌,并可分化为肌源性细胞和血管内皮细胞,可促进小血管再生,有改善心功能的潜能。     

输入不同液体对犬缺血心肌的影响

以8只犬形成自身对照的心肌缺血模型:自左前降冠脉和左旋冠脉随机选出两个基本一致的分支并同时结扎30分钟,以同样灌注压力和速度分别输入辅酶Q_(10)及生理盐水,共2小时。每只犬心肌分成三个区域:1):给药区;2) 盐水对照区;3) 正常区。实验结束时分别从三个区域取材测定MDA含量、NAG酶活性,线粒体横截面积、密度及此表面、局部心肌收缩力、心肌缺血和坏死区面积。结果:给药区MAD含量、NAG酶活性、线粒体横截面积和心肌坏死量、心肌细胞损伤程度明显低于盐水对照区,(MDA含量:nmol/100mg·pro 278.37±51.07,203.08±36.67和633.06±93.47,P<0.01;NAG酶;U/g0.19±0.02,0.17±0.04和0.38±0.06,P<0.05;心肌坏死量:18±2%和30±1%)而局部心肌收缩力和线粒体密度等明显高于盐水对照区,提示辅酶Q_(10)对缺血心肌具有保护作用。     

别嘌呤醇降低大鼠心肌非梗死区胶原重塑

目的探讨黄嘌呤氧化酶抑制剂别嘌呤醇对大鼠非梗死区心肌胶原重塑的影响。方法结扎冠脉前降支制作大鼠心肌梗死模型,随机分为假手术组,心肌梗死组和别嘌呤醇组,每组分别于7、14、21和28d时测定心肌组织胶原含量,Ⅰ、Ⅲ型胶原容积分数(CVF)、mRNA的改变及Ⅰ/Ⅲ型胶原比值,黄嘌呤氧化酶(XO)和清除活性氧活力。28d时另检测XO蛋白表达及左心室病理改变。结果心肌梗死组心肌胶原含量,Ⅰ、Ⅲ型CVF及mRNA升高,Ⅰ/Ⅲ型胶原比值先下降后升高,XO活力增加,清除活性氧活力降低(P<0.05或P<0.01)。别嘌呤醇组明显缓解了上述指标的变化。结论别嘌呤醇能够降低非梗死区胶原沉积和Ⅰ/Ⅲ型胶原比值,改善心肌梗死后心肌胶原重塑。     

高血压患者冠状动脉储备功能的临床研究

目的探讨老年高血压患者冠状动脉储备功能 (CFR)。方法冠状动脉造影正常的高血压患者76例 ,无左心室肥厚 (LVH)32例 (Ⅰ组 ) ,合并LVH44例 (Ⅱ组 ) ,正常对照组26例 (Ⅲ组 )。检查前停服所有血管活性药物至少5个半衰期 ,3d内未服用茶碱类药物。三组受检者隔日分别静脉注入99mTc -MIBI30mci行静态、运动心肌核素断层显像 ,潘生丁以0.84mg/kg剂量缓慢静脉注射 ,于注射前、后即刻2、4、6min测量血压 ,记录18导朕心电图。结果心肌核素显像 :Ⅰ组运动后单光子发射型计算机断层仪 (ECT)呈缺血性改变3例 (9.4% ) ,Ⅱ组运动后ECT呈缺血性改变11例 (25.0 % ) ,有反向再充填现象2例 (4.5 % ,P<0.05)。心电图潘生丁试验 :Ⅰ组阳性1例 (3.1 % ) ,可疑阳性3例(9.4 % ) ;Ⅱ组阳性7例 (15.9 % ) ,可疑阳性9例 (20.5 % ,P<0.05)。心电图潘生丁试验阳性或可疑阳性伴ECT缺血性改变 :Ⅰ组 :无 ;Ⅱ组8例 (18.2 % ,P<0.01)。正常对照组心肌核素显像及潘生丁试验均无异常。结论高血压患者存在不同程度CFR下降 ,合并LVH尤为明显 ,其原因可能与冠状动脉微循环结构及功能异常有关。     

胚胎干细胞移植治疗急性心肌梗死后心肌病理形态学及血流动力学变化

目的：探讨胚胎干细胞(ESC)移植治疗急性心肌梗死(AMI)后心肌组织形态学及血液动力学变化。 方法： Wistar大鼠40只随机分为正常对照组、梗死未治疗组(梗死组)、梗死中心移植组(中心组)、梗死周边移植组(周边组)共4组。结扎冠状动脉左前降支制成心肌梗死模型，梗死后1周移植体外分化并经标记的ESCs，移植后4周分别检测组织形态及血流动力学指标的改变。 结果： 移植后4周，周边组移植细胞稳定存活，而中心组移植细胞未能存活。心功能及组织学检测表明中心组与梗死组无显著差异(P＞0.05)；与梗死组比较，周边组梗死面积显著小于梗死组(P＜0.01)，(21.0±1.3)% vs (40.7±2.2)%；左室重量小于梗死组(P＜0.01)，(702.0±24.0)mg vs (882.2±32.6)mg；反映左室收缩功能的指标+dp/dtmax和LVSP均大于梗死组(P＜0.01)，分别为 (7.9±0.7)×103mmHg/s vs (5.9±0.5)×103 mmHg/s和(117.5±10.7) mmHg vs (89.2±8.1) mmHg；而LVEDP均明显小于梗死组(P＜0.01)，(8.5±0.3)mmHg vs (13.6±1.2)mmHg。 结论： 急性心肌梗死后于梗死周边区移植ESCs可以阻止心室重构、减少瘢痕面积、改善心功能。     

E-cadherin, N-cadherin, and calretinin in pleural effusions: the good, the bad, the worthless

The distinction between reactive mesothelial cells (RMC), malignant mesothelioma (MM), and metastatic adenocarcinoma (ACA) in pleural effusions may be impossible based on morphology alone. E-cadherin, N-cadherin, and calretinin are newly described immunocytochemical markers which can potentially be utilized for facilitating this distinction. E-cadherin and N-cadherin are calcium-dependent intercellular adhesion molecules expressed in epithelial cells and mesenchymal/mesothelial cells, respectively. The differential expression of E-cadherins in epithelial cells and N-cadherins in mesothelial cells has been utilized to differentiate reactive mesothelial cells, MMs and ACAs. Calretinin is a calcium-binding protein within the family of EF-hand proteins. It is abundantly expressed in peripheral and central nervous tissues, and has been shown to consistently immunoreact with mesothelial cells. We studied cell block sections from 77 pleural effusions (22 RMC, 26 MM, and 29 ACA) to investigate the potential immunocytochemical use of anti-E-cadherin, anti-N-cadherin, and anti-calretinin antibodies for differentiating between RMC, MM, and ACA in pleural effusions. A modified avidin-biotin peroxidase complex (ABC) method was used. E-cadherin immunostaining was observed in 14% of RMC, 46% of MMs, and 97% of ACAs. A distinct membrane staining pattern was seen in ACAs. The pattern of staining was cytoplasmic in all reactive RMC and varied from membrane to cytoplasmic in MMs. Anti-N-cadherin immunoreacted with 77% of RMC, 35% of MMs, and 48% of ACAs. Twenty-seven percent of RMC, 58% of MMs, and 31% of ACAs immunoreacted with anti-calretinin. Based on these results, we conclude that anti-E-cadherin is a potentially useful marker in the distinction of ACA cells from RMC. However, it is not as useful for the distinction of ACA and MM. Anti-N-cadherin and anti-calretinin did not reliably distinguish between reactive mesothelial, MM, and ACA cells in pleural effusions.     

Nasal obstruction, the airway, and the athlete

Rhinitis is a common condition that affects a significant proportion of the general population, as well as a high proportion of athletes. Nasal congestion is a predominate symptom of the late-phase reaction in allergic rhinitis and can have far-reaching effects that extend through the airway and beyond the nose. Rhinitis is often found in conjunction with asthma and is a risk factor for asthma. Nasal obstruction, which does not permit conditioning of inspired air by the nasal turbinates, may contribute to asthma symptoms and the development of asthma. These adverse conditions may be especially troublesome for the high-performance athlete who has increased nasal airflow turbulence and who competes under extreme conditions that may worsen rhinitis and asthma. Under the theory of the unified airway, an immune response induced in the nose may extend into the lungs via cytokines and other inflammatory mediators. Nasal congestion can significantly contribute to sleep dysfunction, leading to daytime fatigue and decreased performance. Treatment of allergic rhinitis can improve sleep and foster productivity. Control of rhinitis and nasal congestion, which is obtained by various therapies, may reverse lower airway tendency to bronchoconstriction.     

Multiple sclerosis,the microbiome,TLR2, and the hygiene hypothesis

The pathophysiology of autoimmune diseases such as Multiple Sclerosis (MS) involves a complex interaction between genetic and environmental factors. Studies of monozygotic twins suggest a significant role for environmental factors in susceptibility to MS. Numerous studies, driven by the “Hygiene Hypothesis,” have focused on the role of environmental factors in allergic and autoimmune diseases. The hygiene hypothesis postulates that individuals living in environments that are too “clean” lack the requisite exposure to “immune-tolerizing” microbial products, resulting in poorly regulated immune systems and increased immune-mediated diseases. Interestingly, few studies have linked MS with the hygiene hypothesis. Similarly, although numerous studies have examined the role of the microbiome in autoimmune diseases, there has been no consistent documentation of disease-specific alterations in the MS microbiome. In this review, we present evidence that integrating the hygiene hypothesis and the microbiome allows for the identification of novel pathophysiologic mechanisms in MS.Our central hypothesis is that the microbiome in MS represents a “defective environment” that fails to provide normal levels of “TLR2-tolerizing” bacterial products to the systemic immune system. Consistent with the hygiene hypothesis, we posit that this defective microbiome function results in abnormally regulated systemic innate immune TLR2 responses that play a critical role in both the inflammatory and defective remyelinative aspects of MS. We have completed proof of concept studies that support the inflammatory, remyelinating, and human immune response components of this paradigm. Our studies suggest that induction of TLR2 tolerance may represent a novel approach to treating MS, inhibiting autoimmune inflammation while simultaneously facilitating remyelination.