色胺酮对心肌缺血大鼠心功能和心肌组织COX-2蛋白表达等影响

目的:观察色胺酮对结扎冠状动脉所致心肌缺血大鼠心功能、心肌病理和心肌中COX-2的影响.方法采用结扎冠状动脉左前降支致心肌缺血模型,色胺酮0.10、0.20、0.30g/kg灌胃给药21天后,观察色胺酮对心肌缺血大鼠心功能、心肌病理和心肌组织COX-2蛋白的影响.结果①色胺酮0.10g/kg对心肌缺血大鼠的心脏功能有明显的改善作用,能增强心肌收缩力,改善心肌舒张的顺应性,表现为左心室内收缩压、左心室内压最大变化速率±dp/dtmax明显升高,与模型组比较有明显差异(P<0.05);②0.10g/kg色胺酮对结扎冠状动脉所致心肌缺血大鼠能明显减轻心肌变性,心肌纤维增生和淋巴细胞浸润;③色胺酮明显抑制缺血心肌组织中COX-2蛋白,其抑制作用随剂量的增大而逐渐增强.结论0.10g/kg色胺酮对大鼠结扎冠状动脉所致心肌缺血损伤具有明显的保护作用.     

类α-蝎神经毒素BmKⅠ对离体大鼠心脏收缩力及电活动的特异调控

本研究探讨了一种特异性钠通道调制剂(Buthus martensi Karsch,BmKⅠ)对离体大鼠心脏收缩力及电活动的调制作用.离体心脏灌流实验显示(1)BmKⅠ(0.5-10 μmol/L)剂量依赖地增强大鼠心肌收缩力,左心室最大发展压(LVDPmax)以及dp/dtmax与对照组相比均显著增强(n=6,P＜0.05),同时可触发正性变时作用(n=6,P＜0.05);(2)大剂量BmKⅠ(20μmol/L)引起负性肌力作用及心动过缓;(3)冠脉流量随心脏收缩力的增强反而减小,应用500nmol/L BmKⅠ时冠脉流量由14.5 ml/min降至8.6 ml/min(n=6,P＜0.05);此外,心电图记录表明BmKⅠ(0.5-10μmol/L)可触发心动过速及复杂的心律失常等电活动变化;正常灌流液洗脱后BmKI引起的大鼠心脏收缩力及电活动的改变可部分恢复.由于β-肾上腺素能受体阻滞剂普奈洛尔预先应用抑制了儿茶酚胺类神经递质的释放,提示BmKⅠ引起的大鼠心脏收缩力及电活动的改变不是由于其调节儿茶酚胺类神经递质的释放及随后β-肾上腺素能受体的激活,而可能与其对心肌电压门控钠通道的调控有关.     

枸骨中3种化合物的心血管药理作用

从枸骨中分离了20个化合物,对其中的3个进行了心血管方面的药理作用研究。结果表明,3,4—二羟基桂皮酸和胡萝卜甙对小鼠缺氧、氯仿诱发的小鼠心室纤颤及脑垂体后叶素诱发的大鼠心肌缺血均无保护作用,也不能改变豚鼠离体心肌的心率、冠脉流量及心肌收缩力。3—β—O—（β—D—吡喃葡萄糖基)—α—L—吡喃阿拉伯糖基坡摸酸—β—28—O—D—吡喃葡萄糖酯(命名为枸骨甙4)对小鼠缺氧、氯仿诱发的小鼠心室纤颤无保护作用,对脑垂体后叶素诱发的心肌缺血有一定的保护作用,不改变豚鼠离体心肌的心率和冠脉流量,但可显著降低心肌收缩力。     

纳络酮对离体心房肌收缩力及搏动频率的作用

目的和方法：采用离体心房灌流模型,观察非特异性阿片受体拮抗剂纳络酮对离体心房的变时变力作用,旨在探讨纳络酮对心肌的直接作用。结果：①在１５～１２０ μｍｏｌ／Ｌ的浓度范围内,纳络酮呈剂量依赖性地降低右房的自发搏动频率,增加心房肌的收缩张力;②当α,β受体阻断或μ受体激动后,纳络酮对离体心房的作用仍然存在;③纳络酮可延长心房肌的功能性不应期。结论：纳络酮对心肌具有不依赖于中枢及交感神经系统的直接作用,心脏可能是另一个不通过阿片受体即可对纳络酮发生反应的器官     

α和β受体阻断剂对早期缺血心肌多发早搏阈的影响

本实验在35只兔心脏上观察了α和β受体阻断剂对心肌缺血早期MET变化的影响,并初步分析了α受体阻断剂抗心律失常效应的作用机理。实验结果表明,β与α受体阻断剂对MET 的影响明显不同。β受体阻断剂心得安可使正常心脏与缺血心脏的MET同等程度的升高,而对阻断冠脉后 MET的降低无改善作用。与此相反,α受体阻断剂哌唑嗪对正常心脏的MET 无明显影响,但可使阻断冠脉血流后 MET降低的百分率明显减轻,此效应与血压变化和扩血管作用无直接关系。上述结果提示,β受体阻断剂可通过提高正常和缺血心脏MET 的绝对值发挥抗心律失常效应,而α受体阻断剂则有特异性的提高缺血心肌MET 的作用。     

降钙素基因相关肽在离体大鼠心肌缺血后处理中的作用

目的:观察降钙素基因相关肽(CGRP)在离体大鼠心肌缺血后处理保护中的作用。方法:采用离体大鼠全心停灌心肌缺血复灌模型。测定心室动力学指标、复灌各时间点冠脉流出液中乳酸脱氢酶(LDH)含量和心肌组织formazan含量的变化。结果:与缺血/复灌组相比,缺血后处理组明显增加心脏formazan含量,降低冠脉流出液中LDH含量,促进左室发展压、左室做功和冠脉流量的恢复。CGRP受体阻断剂CGRP-(8-37)和线粒体ATP敏感性钾通道阻断剂5-HD均减弱了缺血后处理的作用,且CGRP-(8-37)阻断了线粒体ATP敏感性钾通道开放剂Diaz的心肌保护作用。结论:缺血后处理可能通过促进线粒体ATP敏感性钾通道的开放,引起内源性降钙素基因相关肽的释放发挥心肌保护作用。     

心交感神经对缺血心肌区血液中TXB2和6—酮—PGF1α浓度变化的影响

本实验在54只麻醉开胸犬,分别观察了心交感神经和α、β受体阻断剂对心肌缺血早期血小板功能变化的影响。结果表明,阻断冠脉后,心肌缺血区血液中TXB_2和6-酮-PGF_(1α)含量明显升高,血小板计数减少,随缺血时间延长,变化程度也增大。缺血心肌局部外敷2％利多卡因湿沙条或切除双侧星状神经节,分别阻断心交感神经的传入和传出效应,发现阻断冠脉后各参数变化程度明显减轻,与单纯阻断冠脉后各参数变化相比,有显著差异,P<0.01。切除星状神经节并由静脉输注去甲肾上腺素后再阻断冠脉,可重新恢复单纯阻断冠脉后的各参数变化,但输注生理盐水无影响。α和β受体阻断剂对上述参数的影响途径不同。α_2受体阻断剂育亨宾和非选择性α受体阻断剂酚妥拉明,可明显减轻TXB_2和6-酮-PGF_(1α)升高及血小板计数降低的程度,与单纯阻断冠脉后的各参数变化程度相比,有显著差异,P<0.01。但α_1受体阻滞剂哌唑嗪无此作用。和α_2受体阻断剂一样,β受体阻断剂心得安对缺血后上述参数的变化也具有明显改善效应。这些结果提示,心交感神经在血小板功能变化中具有重要作用;育亨宾和酚妥拉明是通过阻断血小板膜α_2受体发挥作用的;在输注心得安而未阻断血小板膜α_2受体时所看到对缺血后血小板功能参数的改善效应,提示β受体阻断剂可能     

腺苷及其受体阻断剂对蟾蜍离体心脏功能的影响

实验采用离体心脏灌流方法,观察了腺苷,腺苷受体特异性阻断ＤＰＣＰＸ以及非特异性腺苷受体阻断剂茶碱对两栖类动物蟾蜍的离体心脏力和心率的影响。结果显示,腺苷对心脏收缩力和心率有明显的剂量依赖性抑制作用。单纯的ＤＰＣＰＸ或茶碱对心肌收缩力和心率无显著影响,但在含腺苷的灌流液中加入ＤＰＣＰＸ或茶碱后,对腺苷有明显的拮抗效应。     

在大鼠心肌由兴奋α-肾上腺素受体引起的变力反应特性

用多导记录仪同步记录了离体灌流大鼠心脏的变力反应曲线和心电图,并分析了这些指标在肾上腺素能药物作用下所发生的时相变化。150个鼠心的实验结果表明。大鼠心肌存在口一肾上腺素受体,兴奋时发生正性变力作用,α受体变力反应的方式和时间不同于β受体;β受体兴奋产生快反应,收缩振幅和心率迅速增长达到峰值,然后收缩振幅较快衰减;而α受体兴奋引起缓反应,继快反应之后几十秒至二分钟之间收缩振幅达峰值,其增长速率较慢,且持续时间较长。快反应为心得安所阻断;缓反应为酚妥拉明所阻断。由此推论:内源性去甲肾上腺素和肾上腺素先兴奋心脏的β受体,引起较为短暂的快反应,同时通过α受体产生缓反应,使心肌收缩力较为缓慢而持久地增强,而心率不加快或略为减慢,以此方式实现它们对心脏活动的调节。     

δ-阿片受体在缺血后处理心肌保护中的作用

目的：探讨δ-阿片受体是否参与缺血后处理对抗心肌缺血/复灌（I/R）损伤和心肌细胞低氧/复氧（H/R）损伤作用及其机制。方法：采用离体大鼠心脏Langendorff灌流模型,全心停灌30 min、复灌120 min复制I/R模型。测定心室力学指标和复灌时冠脉流出液中乳酸脱氢酶（lactate dehydrogenase,LDH）活性,实验结束测定心肌组织formazan含量。酶解分离的心肌细胞采用低氧60min、复氧60min复制H/R模型,测定心肌细胞存活率。结果：在离体心脏模型上,与I/R组相比,缺血后处理组（停灌后复灌即刻立即给予6次全心停灌/复灌循环）心肌组织的formazan含量明显增高,复灌期间冠脉流出液中LDH明显降低,同时缺血后处理明显改善心室力学指标,缓解冠脉流量的减少 在分离心肌细胞模型上,低氧后处理明显提高心肌细胞存活率。δ-阿片受体阻断剂naltrindole（NTI）和线粒体钙激活钾通道（KCa）阻断剂paxilline（Pax）在离体大鼠心脏模型和分离心肌细胞模型上均能明显减弱缺血后处理的作用。在心肌细胞模型上,与H/R组相比,δ-阿片受体激动剂DADLE明显提高心肌细胞存活率,其作用可被paxilline所阻断。结论：缺血后处理具有抗心肌缺血/复灌损伤的作用,这种保护作用可能与其激活δ-阿片受体和开放KCa有关。     

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.