牛磺酸对大鼠肢体缺血倡灌注后肺损伤时磷脂酶A2的影响

目的：探讨牛磺酸对大鼠肢体缺血／再灌注后肺损伤时磷脂酶A2（PLA2）的影响。方法：实验采用大鼠肢体缺血／再灌注损伤模型,将Wistar大鼠30只随机分为3组（n=10）,对照组（control）、单纯缺血／再灌注组（1／R）、牛磺酸＋缺血／再灌注组（Tau＋I／R）,分别测定血浆丙二醛（MDA）、黄嘌呤氧化酶（XOD）、超氧化物歧化酶（SOD）以及肺组织Taurine、XOD、SOD、MDA、髓过氧化物酶（MPO）的含量、肺湿／干比值（W／D）和磷脂酶A2（PLA2）的活性。结果：口服牛磺酸可有效地降低肺组织MPO、PLA2和XOD的活性．结论：牛磺酸对大鼠肢体缺血再灌注后肺损伤具有保护作用,其机制之一可能与降低PLA2活性和抑制炎症反应有关。     

蛇床子素在大鼠肠缺血再灌注肺损伤模型中的肺保护机制研究

目的：探讨蛇床子素（Osthole）在大鼠肠缺血再灌注肺损伤（IIRI）中的保护机制。方法：健康雄性SD大鼠40只随机分为假手术组（sham组）、缺血再灌注组（I／R）和两个不同剂量给药组（Ost）,其中缺血再灌注组和给药组采用夹闭大鼠肠系膜上动脉60min后松开动脉夹形成缺血再灌注模型。各给药组于缺血再灌注30min后分别给予5mg／kg、25mg／kg蛇床子素腹腔注射治疗。各实验组动物分别采用HE染色、肺组织水肿（W／D）比值、ELISA检测和免疫组化评价蛇床子素在缺血再灌注肺损伤后的肺保护机制。结果：缺血再灌注30min后,给药组大鼠HE,W／D、IL-1B和TNF—α结果均明显优于对照组（P〈0．05）,并在25mg／kg剂量时表现出最大保护效果,同时Caspase-3蛋白表达水平也显著降低。结论：蛇床子素在大鼠肠缺血再灌注肺损伤后有一定的肺保护作用。     

银杏提取物对大鼠肺缺血/再灌注损伤的保护作用

目的：观察银杏提取物（EGB）对大鼠体外循环肺缺血／再灌注损伤（I／R）的保护作用。方法：建立离体大鼠肺灌流模型．SD大鼠随机分成假手术组（Sham）、I／R组和EGB组,观察大鼠肺组织形态学改变、分别测定肺组织匀浆及灌流液中超氧化物歧化醇（SOD）、丙二醛（MDA）的含量、肺湿干重比（W／D）和平均肺动脉压（MPAP）。结果：HE染色显示EGB组肺损伤明显减轻、肺组织湿／干重比和MPAP显著低于I／R组：EGB组肺脏灌流液和组织匀浆中SOD的活性显著高于I／R组,MDA含量则显著低于I／R组。结论：EGB对大鼠肺I／R损伤具有保护作用。     

粉防己碱对大鼠脑缺血/再灌注后IL-1β、TNF-α和IL-8表达的影响

目的：探讨粉防己碱对大鼠脑缺血／再灌注后炎性因子表达的影响。方法：72只SD大鼠随机分为假手术组（Sham）,缺血／再灌注组（I/R）,粉防己碱处理组（Tet）。采用线栓法复制大鼠右侧大脑中动脉脑缺血／再灌注模型,用放射免疫方法测定脑组织中IL-1β、TNF-α和IL-8的含量。结果：脑缺血／再灌注早期脑组织中IL-1β、TNF-α表达迅速升高,IL-8表达稍滞后;Tet组中脑组织中此三个因子的表达显著降低（P〈0．05或P〈0．01）。结论：粉防己碱抑制大鼠脑组织缺血佴灌注早期炎性细胞因子的表达,减轻炎性反应,对缺血佴灌注脑组织具有保护作用。     

大鼠肢体缺血/再灌注后肺损伤及一氧化氮合酶的变化与意义

目的：研究大鼠肢体缺血／再灌注后急性肺损伤时,内皮型一氧化氮合酶（eNOS）和诱导型一氧化氮合酶（i-NOS）的表达及其在急性肺损伤发生中的作用。方法：雄性Wistar大鼠于后肢根部阻断血流后松解（4h／4h）,分别给予L-Arg和氨基胍（AG）预先干预,分为control、IR、L-Arg和AG组,免疫组织化学方法检测肺组织中iNOS和eNOS的表达,同时检测肺组织中MDA、MPO、W／D和NO2^-／NO3^-值,肺组织形态学观察以评价肺损伤的程度。结果：与control组比较,I／R组eNOS表达降低,iNOS表达增强,MDA、MPO、W／D和NO2^-／NO3^-值增加。肺组织充血、炎细胞浸润,肺泡腔渗液;与I／R组比较,L-Arg组eNOS、iNOS表达无明显变化,NO2^-／NO3^-增加。MDA、MPO、W／D降低,肺组织损伤有减轻趋势,AG组eNOS表达无明显变化,iNOS活性降低,NO2^-／NO3^-减少,MDA、MPO、W／D增加,肺组织损伤有加重趋势。结论：肢体缺血／再灌注急性肺损伤过程中,iNOS表达增加,NO生成增多,在肺损伤发生中有一定的保护作用。     

缺血后适应对局灶性脑缺血/再灌注大鼠p38表达的影响

目的：探讨缺血后适应对大鼠局灶性脑缺血/再灌注损伤后p38表达的影响。方法：将30只雄性SD大鼠随机分为3组（n=10）：假手术组（sham组）、缺血/再灌注（I/R）组和缺血后适应（IP）组。利用TUNEL法观察神经细胞凋亡的变化,应用Westernblot检测大鼠局灶性脑I/R损伤后p38蛋白表达水平的变化。结果：大鼠脑缺血/再灌注后凋亡细胞数量和p38蛋白表达水平均显著升高,而IP组凋亡细胞数量和p38蛋白表达水平均显著低于IR组（P〈0.01）。结论：缺血后适应可抑制大鼠脑缺血/再灌注后细胞凋亡的发生,此作用可能与下调p38蛋白表达有关。     

缺血后适应对局灶性脑缺血/再灌注大鼠caspase-3表达的影响

目的：探讨缺血后适应对大鼠局灶性脑缺血/再灌注损伤后caspase-3表达的影响。方法：大脑中动脉线拴法复制大鼠局灶性脑缺血/再灌注损伤动物模型。将30只雄性SD大鼠随机分为3组（n=10）：假手术组（sham组）、缺血/再灌注（I/R）组和缺血后适应（IP）组。利用原位缺口末端标记法观察神经细胞凋亡的变化。应用Western blot检测大鼠局灶性脑缺血/再灌注损伤后caspase-3蛋白表达水平的变化。结果：大鼠脑缺血/再灌注后凋亡细胞数量和caspase-3蛋白表达水平均显著升高,而缺血后适应组凋亡细胞数量和caspase-3蛋白表达水平均显著低于缺血/再灌注组（P〈0.01）。结论：缺血后适应可抑制大鼠脑缺血/再灌注后细胞凋亡的发生,此作用可能与下调caspase-3蛋白表达有关。     

内源性一氧化碳减轻大鼠双侧后肢缺血再灌注所致的肺损伤

通过观察血红素氧化酶（HO）阻断剂－－锌原卟啉（ZnPP)对肺组织、肺泡间质多形核白细胞数目肺组织丙二醛含量和湿重干重之比的影响,并对肺组织HO活性和血内碳氧血红蛋白水平（COHb）进行检测,以探讨内源性HO／一氧化碳（CO）在肢体缺血再灌注（I／R）所致肺损伤中的作用。结果发现,大鼠双侧后肢I／R可导致急性肺损伤,同时使肺组织中HO活性和血内COHb水平显著升高;应用ZnPP预处理可使HO活性和COHb水平显著降低,但肺损伤却进一步加重。上述实验结果表明,肢体I／R致肺损伤时,肺组织中HO活性和内源性CO生成增多或减轻大鼠肢体I／R所致的肺损伤。     

缺血预适应对大鼠肢体缺血/再灌注后小肠细胞凋亡的影响

目的：观察大鼠肢体缺血再灌注后小肠粘膜自由基及钙含量改变与细胞凋亡情况．以及缺血预适应对其变化的影响。方法：将雄性Wistar大鼠18只,随机分为对照（Control）组,缺血／再灌注（I／R）组和缺血预适应（IPC＋I／R）组,分别测定血浆和小肠组织超氧化物歧化酶（SOD）、黄嘌呤氧化酶（XOD）、丙二醛（MDA）的含量,小肠组织钙及线粒体钙含量;小肠组织的Bel-2和Bax蛋白的表达水平;检测小肠细胞凋亡情况。结果：肢体I／R后血浆和小肠粘膜SOD减少而XOD和MDA增加;小肠组织钙及线粒体钙含量增多;Bel-2蛋白表迭和Bax表达增多,但Bel-2／Bax比值降低;凋亡细胞增多。IPC减轻了I／R后引起的XOD、MDA含量的升高,并且增加了SOD的含量;减轻了组织和线粒体钙超载;Bel-2的表达则明显升高而Bax表达较I／R组明显减少,Bel-2／Bax比值升高;凋亡细胞减少。结论：肢体IR引起小肠粘膜自由基的增多,钙超栽,凋亡细胞增多;IPC可能通过减少自由基的产生及钙超载,抑制细胞凋亡而对肢体I／R继发的小肠功能损伤起保护作用。     

siRNA沉默过度内质网应激下DⅨ基因在缺血／再灌注肺损伤中的作用

目的：探讨siRNA沉默过度内质网应激（ERS）下C．Jun氨基末端激酶（州K）通路在缺血／再灌注肺凋亡中的作用。方法：采用C57BIM6J小鼠左侧肺原位缺血／再灌注（IVR）损伤模型。实验随机分为7组（／7,=10）,包括假手术组（Sham组）,缺．tk／再灌注组（I／R组）,PBS＋Lipofectamine2000TM转染试剂组（VR＋PBS＋Lipo组）,阴性对照组（VR＋SCR组）,JNK-siRNA~g（VR＋siRNAJNl（1组、I／R＋siRNAJ眦组、I／R＋si时忱JNl。组）。各组实验结束后处死小鼠,留取左肺,分别检测肺湿干重比（W／D）和总肺水含量（TLW）;光镜观察肺组织形态结构变化,并进行肺组织损伤评估（IQA）;RT-PCR、检测JNK和葡萄糖调节蛋白78（GRP78）的基因表达;Westernblot检测磷酸化JNK（p-JNK）和GRP78的蛋白表达;原位缺口末端标记法（TUNEL法）检测肺细胞凋亡指数（AU。结果：与Sham组相比,I／R＋PBS＋Lipo组和SCR组各组W／D、’ILw、IQA、JNK与GRP78mRNA和p-JNK、GRP78蛋白质表达量及AJ均明显升高（P〈0．01）,光镜显示肺组织结构出现明显损伤性变化,且各组两两比较,上述各指标均无统计学差异;与I／R＋PBS＋Lipo组和SCR组相比,JNK-siRNA各组GRP78表达水平无明显变化,余各指标均降低（P〈0．05,P〈0．01）且肺组织损伤减轻。结论：I／R引起肺组织细胞发生过度的ERS,并通过JNK通路引起细胞凋亡,损伤肺组织。     

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.     

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.     

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