氨甲酰胆碱(Carbamylcholine)对大鼠缺血心室致颤阈值的影响及其与cAMP、cGMP的关系

本实验以心室颤动阈(VFT)作为心室易颤性的指标,观察胆碱类物质氨甲酰胆碱对大鼠缺血心室 VFT 的影响及其与心肌 cAMP 和 cGMP 水平的关系。实验结果表明,氨甲酰胆碱可提高正常心脏和急性局部缺血心脏的 VFT,提高缺血和未缺血心肌的 cGMP 水平,但明显降低缺血心肌 cAMP 水平,使缺血和未缺血心肌的 cAMP/cGMP 比值显著降低,其作用与肾上腺素正好相反。实验结果还表明,急性局部缺血心脏的 VFT 与缺血心肌 cAMP/cGMP 比值之间有密切的负相关关系,相关系数 r=-0.905(n=22,P<0.001)。上述结果提示缺血心肌 cAMP/cGMP 比值的提高可能是急性心肌梗塞早期发生心室纤维性颤动的重要因素。     

阿托伐他汀预处理对心肌缺血再灌注损伤大鼠心室重构、炎症反应和氧化应激的影响

目的:研究阿托伐他汀预处理对心肌缺血再灌注损伤大鼠心室重构、炎症反应和氧化应激的影响。方法:选取90只SD级大鼠进行研究,将其随机分成假手术组、缺血再灌注组、阿托伐他汀组,每组30只。假手术组与缺血再灌注组大鼠予以生理盐水(5 m L/d)连续灌胃7d处理,阿托伐他汀组予以阿托伐他汀20 mg/(kg·d)连续灌胃7 d,上述干预结束后,缺血再灌注组与阿托伐他汀组大鼠通过阻断大鼠冠状动脉左前降支的方式建立心肌缺血再灌注损伤模型。比较三组大鼠心室重构指标水平、炎症反应以及氧化应激相关指标水平。结果:缺血再灌注组、阿托伐他汀组大鼠的左室相对重量、右室相对重量、室间隔厚度、肿瘤坏死因子-α(TNF-α)、白细胞介素-1β(IL-1β)、丙二醛(MDA)、乳酸脱氧酶(LDH)水平均高于假手术组,且阿托伐他汀组大鼠上述指标均低于缺血再灌注组(均P<0.05);缺血再灌注组、阿托伐他汀组大鼠白介素-10(IL-10)、超氧化物气化酶(SOD)水平低于假手术组,且阿托伐他汀组大鼠IL-10、SOD水平高于缺血再灌注组(均P<0.05)。结论:阿托伐他汀预处理可有效预防心肌缺血再灌注损伤大鼠心室重构,同时可在一定程度上改善大鼠的炎症反应和氧化应激反应。     

犬实验性急性心肌梗塞早期心肌细胞膜脂流动性的改变

为了解急性心肌梗塞(AMI)时心肌细胞膜脂流动性(LFU)的变化,用荧光分光光度计偏振法测定了20只实验性AMI早期犬的心肌细胞LFU。结果表明,AMI早期心肌细胞LFU与正常组比较明显降低(P<0.01),其降低程度与心肌缺血时间长短和心肌细胞损伤程度有关。LFU在冠状动脉(CA)结扎后1min时即出现降低,与心外膜电图S—T段弓背向上损伤性改变同时发生,而明显早于外周血清肌酸磷酸激酶(CPK)和谷草转氨酶(AST)以及心肌组织病理形态学的改变,后者在CA结扎后240min出现变化。因此,LFU可作为AMI早期反映心肌细胞缺血损伤及其程度的一种敏感标志。     

急性心肌梗塞患者血浆肌钙蛋白T快速检测的临床价值

诊断急性心肌梗塞(AMI),心脏酶学检查具有重要的临床价值。但传统检测的各种酶学标志物存在灵敏度较低或升高持续时间较短等不足,临床上尚不能及早、准确地反映心肌缺血损伤情况。近年来,心肌特异性肌钙蛋白T(Troponin T,TnT)测定为AMI的早期诊断提供了一个敏感、特异的检查方法     

江浙蝮蛇抗栓酶对兔缺血心肌电生理学变化的影响

本研究观察了江浙蝮蛇抗栓酶(svate)对缺血心肌电生理学变化的影响。结果表明,静脉注射svate,使阻断冠脉后兔血小板聚集功能和心脏电生理各指标变化明显减轻。缺血50min时,血小板聚集率仅增加4±13％,静息电位减小15.8±0.1％,动作电位幅度降低17.8±0.1％,复极化50％和90％时程分别缩短12.3±0.1％及延长4±0.1％,不应期差值为4.2±7.8％,室颤阈(VFT)降低15.4±8.1％,与单纯阻断组各参数的百分率变化相比,p值均<0.01,证明svate具有改善有效不应期和提高VFT的作用。     

法舒地尔对急性心肌梗死大鼠心肌组织中Rho激酶的影响及心肌保护作用(英文)

目的:分析急性心肌梗死(AMI)后大鼠心肌组织Rho激酶表达的变化及心肌细胞凋亡情况,观察法舒地尔对急性心肌梗死(AMI)后大鼠心肌组织Rho激酶表达的影响,探讨法舒地尔对心梗后心肌的保护作用。方法:选取雄性Wistar大鼠,随机分为三组:治疗组、AMI组、假手术组。治疗组及AMI组均结扎左前降支(LAD)制作AMI模型;假手术组只在其LAD下穿线不结扎。治疗组给予法舒地尔5mg/kg,腹腔注射,每日两次;对照组和假手术组给予等量生理盐水。1周后,EvensBlue及NBT双染色确定缺血面积及梗死面积,RT-PCR法测定rho激酶mRNA的表达,DNA断裂的原位末端标记法(T UNEL法)检测缺血区心肌细胞凋亡指数(AI),免疫组化测定凋亡相关蛋白bcl-2及bax表达的变化。结果:1周后,AMI组与假手术组相比,AMI组大鼠Rho激酶mRNA表达增加(P0.01),凋亡相关蛋白bax表达增加(P0.01),bcl-2表达减少(P0.01),AI明显增加(P0.01)。治疗组与AMI组相比,梗死面积显著减小(P0.05),Rho激酶mRNA及bax表达显著减少,AI显著降低,bcl-2表达显著增加(均P0.01)。结论:大鼠AMI后,心肌组织中Rho激酶的表达增加,心肌细胞凋亡指数增加,连续应用法舒地尔1周能有效减少心肌细胞凋亡指数,起到心肌保护的作用。     

全心缺血早期阶段室性心律失常仿真研究

为了分析全心缺血早期阶段对心脏电生理活动的影响,以及探讨诱发的室性心律失常机制,本研究考虑了缺血情况下高钾、酸液过多、局部缺氧的情况,结合详细的人类心室细胞生物物理上的动力学特征,开发了一个人体心室细胞和组织全心缺血模型.实验结果表明,全心缺血缩短了动作电位时程(action potential duration,APD),且减缓了兴奋的传导速率(conduction velocity,CV).同时,由于全心缺血降低了动作电位时程曲线(action potential duration restitution,APDR)斜率,且增大了有效不应期(effective refractory period,ERP),因此有利于维持折返波的稳定传导,使得室速不易转化为室颤.另一方面,尽管全心缺血导致了组织易感性的增加,但是由于其需要更长的异位刺激长度来保证折返波的形成,因此也在一定程度上降低了心律失常的发生概率.     

PP2对大鼠面神经缺血损伤的保护作用

目的:探讨PP2(4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine)在大鼠面神经缺血损伤模型中的保护作用,为进一步探索面神经缺血损伤的治疗方法提供实验依据。方法:实验选取40只雄性SD大鼠,分为四组:假手术组,损伤组,DMSO溶剂对照组和PP2干预组。手术组沿耳廓外上缘行弧形切口,分离暴露出岩动脉,双极电凝灼断。假手术组暴露出岩动脉但不予灼断。PP2干预组和DMSO溶剂对照组于术前30 min分别脑室注射15 μg(总体积10 μL)PP2或相同体积DMSO。于3 d后观察各组大鼠的行为学变化,同时运用免疫共沉淀和免疫印迹的技术分析其中分子机制。结果:(1)PP2干预组的大鼠相对于手术组和DMSO溶剂对照组,瞬目反射和触须动度明显好转(2)大鼠面神经缺血损伤时,损伤组相对于假手术组,NMDAR-PSD95-Src的结合明显增加(P0.05)(3)PP2干预组NR2A-PSD95-Src的结合相对于手术组和DMSO溶剂对照组明显降低(P0.05)。结论:大鼠面神经缺血损伤时,存在NMDAR-PSD95-Src形成的信号通路,PP2可以有效的抑制NMDARPSD95-Src信号通路的形成,从而起到面神经保护作用。     

三七皂苷R1对大鼠缺血心肌VEGF、bFGF的影响

目的:探讨三七皂苷R1对大鼠缺血心肌VEGF、bFGF的影响。方法:选择雄性Wistar大鼠39只,建立心肌梗死(AMI)模型,术后24h存活大鼠随机分为药物组(n=13)、对照组(n=13),另设假手术组(n=8)。药物组给予三七皂苷R1水溶液(2.5 mg·kg-1·d-1)腹腔注射、对照组及假手术组给予等体积生理盐水腹腔注射,用药4周。于实验终点处死大鼠,心肌组织取材,Ⅷ因子染色计数微血管数(MVC)及微血管密度(MVD),免疫组织化学法观察缺血心肌VEGF、bFGF蛋白的表达。结果:药物组及对照组MVC、MVD均高于假手术组,且药物组高于对照组(P0.05);大鼠缺血心肌药物组及对照组VEGF、bFGF蛋白表达均高于假手术组(P0.05),且药物组高于对照组(P0.05)。结论:三七皂苷R1促进大鼠缺血心肌血管再生同时可上调缺血心肌VEGF、bFGF蛋白水平。     

白芍总苷对心肌缺血再灌注大鼠内质网应激因子CHOP、GRP78、GRP94的表达及凋亡的影响

目的:研究白芍总苷(TGP)对心肌缺血再灌注(I/R)大鼠内质网应激因子CCAAT/增强子结合蛋白的同源蛋白(CHOP)、葡萄糖调节蛋白78(GRP78)、葡萄糖调节蛋白94(GRP94)表达及凋亡的影响。方法:选择健康清洁级SD大鼠75只,根据随机数字表法分成5组,每组15只,分别记为假手术组、I/R组、50 mg/kg TGP组、100 mg/kg TGP组以及200 mg/kg TGP组。检测并对比各组大鼠CHOP、GRP78、GRP94水平,对比分析各组大鼠心肌I/R指标、梗死面积率以及心肌细胞的凋亡率。结果:I/R组和TGP各组的CHOP、GRP78及GRP94水平均明显高于假手术组,且TGP各组较I/R组明显更低(均P0.05)。100 mg/kg和200 mg/kg TGP组的CHOP、GRP78及GRP94水平均明显低于50 mg/kg TGP组,且200 mg/kg TGP组较100 mg/kg TGP组明显更低(均P0.05)。I/R组和TGP各组缺血30 min的T波改变、再灌注120 min的T波改变及LVEDP水平均明显高于假手术组,LVSP、+dp/dtmax及-dp/dtmax水平均明显低于假手术组(均P0.05)。与I/R组相比,TGP组缺血30 min的T波改变、再灌注120 min的T波改变及LVEDP水平呈剂量依赖型下降,而LVSP、+dp/dtmax及-dp/dtmax水平呈剂量依赖型上升(均P0.05)。I/R组和TGP各组的梗死面积率和心肌细胞的凋亡率均明显高于假手术组(均P0.05)。与I/R组相比,TGP组的梗死面积率和心肌细胞的凋亡率水平呈剂量依赖型下降(均P0.05)。结论:应用TGP能够明显降低MIRI大鼠内质网应激因子CHOP、GRP78、GRP94的表达,调节心肌缺血和再灌注相关标志物或临床参数的水平,显著减少心肌缺血和再灌注所致的心肌梗死面积率及细胞凋亡率。     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Comparative morphology of the carpel in the Liliaceae: Hewardieae, Petrosavieae, and Tricyrteae

The young pistils in the melanthioid tribes, Hewardieae, Petrosavieae and Tricyrteae, are uniformly tricarpellate and syncarpous. They lack raphide idioblasts. All are multiovulate, with bitegmic ovules. The Petrosavieae are marked by the presence of septal glands and incomplete syncarpy. Tepals and stamens adhere to the ovary in the Hewardieae and the Petrosavieae but not in the Tricyrteae. Two vascular bundles occur in the stamens of the Hewartlieae and Tricyrtis latifolia. Ventral bundles in the upper part of the ovary of the Hewardieae are continuous with compound septal bundles and placental bundles in the lower part. Putative ventral bundles occur in the alternate position in the Tricyrteae and putative placental bundles in the opposite. position in the Petrosavieae. The dichtomously branched stigma in each carpel of the Tricyrteae is supplied by a bifurcated dorsal bundle.