兔脑微栓塞模型脑血流动力学的CT灌注动态变化

目的探讨兔脑微栓塞模型CT灌注成像（CT perfusion imaging,CTPI）脑血流动力学的动态变化规律。方法 30只新西兰兔,随机分成两组,A组：假手术对照组5只,B组：微栓塞组25只。经颈外动脉向颈内动脉注入直径约0.5 mm的SiO2颗粒10枚,分别于栓塞后30 min、3 h、6 h、12 h及24 h行CTPI,24 h处死动物取脑组织行HE染色。根据HE染色结果将模型分为缺血组和梗死组,分别观察其脑血流量（cerebral blood flow,CBF）、脑血容积（cerebral blood volume,CBV）和平均通过时间（mean transit time,MTT）的动态变化规律。结果 A组CTPI及HE染色均未见明显异常。B组3只因实验意外死亡,1只因下肢静脉穿刺失败导致CTPI失败,21只行CTPI,其中18只灌注异常,3只未见明显异常。18只灌注异常的兔中,HE染色10只脑梗死,7只脑缺血,1只未见明显异常。30 min时7只缺血兔脑不同程度低灌注,表现为CBF降低,MTT延长,CBV无显著变化,3～6 h低灌注进一步加重,CBV值略降低,12 h低灌注不同程度恢复,24 h进一步恢复。30 min时10只梗死兔脑明显低灌注,表现为CBF及CBV显著降低,MTT显著延长,3只兔低灌注分别在3 h、6 h及12 h不同程度恢复,然后下一时间又迅速降低并随着时间延长进一步加剧,其余7只兔低灌注程度随时间延长逐渐加剧或在一定水平上波动。结论脑缺血3～6 h低灌注最明显,12～24 h低灌注不同程度恢复,而脑梗死随时间延长低灌注程度不断加重或一过性恢复后再次加重。脑缺血的特征是CBF和CBV的不匹配,缺血组织CBF显著降低,CBV无显著变化,而脑梗死则表现为这两个参数的一致性下降。     

大鼠原位膀胱癌模型的建立与CT诊断价值

目的研究N-甲基亚硝基脲诱导大鼠原位膀胱癌模型的构建过程以及计算机断层扫描对大鼠原位膀胱癌的诊断价值。方法50只SD大鼠随机分为两组,对照组A组15只,实验组B组35只。B组大鼠经尿道膀胱内灌注MNU每两周一次,每次2 mg,共4次。A组大鼠用生理盐水以同样的方法灌注。于第14周末对两组大鼠进行膀胱CT扫描诊断,并且处死后取膀胱组织行病理学观察。结果B组28只大鼠CT扫描膀胱均见明显异常,表现为局部肿块突起或膀胱壁不规则增厚、密度不均,病理诊断均为膀胱癌。A组13只大鼠经CT扫描未发现膀胱肿瘤,病理检查未见肿瘤组织。结论MNU可以诱导大鼠原位膀胱癌模型的建立。CT扫描可作为大鼠原位膀胱癌诊断的可靠方法,并能为肿瘤的化疗或放疗等后续实验提供更好的大鼠模型。     

兔急性肠道缺血再灌注损伤模型的建立

目的:建立小肠急性缺血再灌注损伤模型,确定合适的肠系膜上动脉阻断时间.方法:将70只新西兰兔随机按不同的肠系膜缺血时间(0、15、30、45、60min)分为A、B、C、D、E5组,每组14只,取8只用于恢复血供2h后留取各组兔下腔静脉血标本及肠组织,检测血清中MDA含量的变化,光镜下观察小肠组织形态学变化并对小肠黏膜损伤程度进行评分.另6只用于术后24h、 48h及72h生存率的观察.结果:A、B、C组的术后生存率均>83.3%.C、D、E组的MDA含量及肠黏膜损伤评分与A组比较,差异均有显著性(F=12.13～280.24,p<0.01).结论:肠系膜缺血30min,再灌注2h是建立兔小肠急性再灌注损伤的合适时间.     

线栓法制备不同体重KM小鼠局灶性脑缺血/再灌注模型的建立及评价

目的线栓法制备小鼠脑缺血/再灌注模型,并探讨影响该模型稳定性的因素。方法 KM小鼠100只,雌雄各半,体重20～39 g,分别将雌雄KM小鼠随机分为假手术组(n=20)和不同体重实验组(n=80)。其中实验组按小鼠体重分为以下8组:A组(♂,20～24 g)、B组(♂,25～29 g)、C组(♂,30～34 g)、D组(♂,35～39g),E组(♀,20～24 g)、F组(♀,25～29 g)、G组(♀,30～34 g)、H组(♀,35～39 g),每组10只。线栓栓塞法制备局灶性脑缺血/再灌注模型,选用单丝尼龙线(直径0.128～0.180 mm),液体石蜡处理浸泡后,从右侧颈总动脉进线,阻塞大脑中动脉血流,再灌注时拔出线栓,并对模型进行评价,采用的主要观察指标是神经功能损伤评分和2,3,5-三苯基氯化四氮唑(TTC)染色。结果同假手术相比,不同体重实验组小鼠脑缺血再灌注后,出现神经行为功能异常,TTC染色脑组织显示出明显的梗塞灶。与C、D组相比,A、B两组行为学评分以及梗死灶体积显著性增加(P<0.01);与G、H组相比,E、F两组的行为学评分以及梗死灶体积也显著性增加(P<0.01,P<0.05)。雄性KM小鼠与雌性相比,成模率较高且死亡率相对较低。此外,A组与E组相比,其行为学评分显著增加(P<0.01);B组与F组相比,小鼠行为学评分以及脑梗塞体积显著增加(P<0.01)。结论体重在25 g左右的雄性KM小鼠制备模型成功率较高,死亡率较低,适合建立小鼠局灶性脑缺血/再灌注模型。     

脑缺血再灌注损伤大鼠血浆蛋白C活性变化的研究

目的探讨脑缺血再灌注损伤大鼠血浆蛋白C活性的变化及其检测意义。方法取SD大鼠30只,随机分为正常对照组(NC组)、假手术组(SH组)及脑缺血再灌注模型组(IR组),每组10只。线栓法制备左侧局灶性脑缺血再灌注模型,缺血2 h,再灌注24 h,神经功能缺损评分后,右侧颈总动脉取血,离心后取血浆50μl,于-20℃冰冻保存,发色底物法检测蛋白C活性;余血浆2 h内检测凝血功能各指标。结果 IR组大鼠蛋白C活性较NC组及SH组明显降低(P0.01),SH组PC活性较NC组也降低(P0.05);IR组较NC组及SH组PT、APTT明显降低(P0.01),FIB显著增高(P0.01)。结论脑缺血再灌注损伤后PC活性明显改变,检测血浆PC活性的变化对缺血再灌注脑损伤的早期诊断与治疗监测具有重要意义。     

大鼠心肌缺血再灌注模型构建的改良

目的改良大鼠心肌缺血再灌注模型的构建方法,增强实用性。方法32只SD雄性大鼠随机分为四组（A组：伪手术组;B组：缺血组;C组：缺血30 min再灌注组;D组：缺血60 min再灌注组）。缺血过程在人工机械通气条件下完成,术前术中监测心电图变化,模型成功72 h后抽血进行心肌酶谱分析,并观察左室压变化。结果造模成功率为91%。B、C、D组各心肌酶含量明显高于A组（P〈0.05）,C、D组低于B组（P〈0.05）。B、C、D组左室压值低于A组（P〈0.05）,C、D组高于B组（P〈0.05）。结论改进后的模型制备方法简便易行,成功率高,评价指标符合临床应用。     

兔肾积水模型的建立及SPECT和CT灌注成像

目的探索建立肾盂输尿管连接部梗阻所致肾积水的动物模型的可行性;探讨CT灌注成像对积水肾脏肾功能的评估价值。方法10周龄雄性新西兰兔50只随机分组,假手术组20只,分离左侧输尿管后直接关腹。模型组30只,选用腰大肌包埋输尿管造成左侧肾盂输尿管连接部梗阻。术前两组进行单光子发射计算机体层成像（SPECT）比较左肾功能,检验无差异后在术后3月分别行左肾SPECT、CT灌注,以病理检查为佐证,观察两组参数变化,进行CT灌注各项参数和GFR的统计学相关性分析。结果模型组建模成功达70%,呈慢性肾积水病理表现,左肾皮髓质CT灌注参数BF、BV、PS均下降,与相应GFR呈高度正相关。结论腰大肌包埋输尿管的模型制作方法具有可行性。CT灌注参数可作为肾功能状态的评定指标,具有一定的临床指导意义。     

负压封闭引流对兔颅骨外露创面愈合效果的实验研究

目的:探讨负压封闭引流技术(VSD)对兔颅骨外露缺损创面愈合的治疗效果。方法:选取成年新西兰大白兔76只,平均分为四组并建立兔颅骨外露实验模型。其中,A组(19只):于兔颅骨上方制作直径为2.0cm的圆形创面,保留骨膜,采用-120mmHg负压引流和常规换药治疗;B组(19只):实验动物处理同A组,仅采用常规换药治疗;C组(19只):在兔颅骨上制作直径2.0cm的圆形创面,剔除骨膜,治疗方法同A组;D组(19只):实验动物处理同C组,治疗方法同B组。每组各抽取10只,观察创面愈合率和创面愈合时间;其余9只分别在第7天、10天、20天、30天进行取材检测,分析疗效机制。结果:A组创面愈合时间为19.40±1.65天,B组为24.00±2.31天;C组为25.40±4.43天,D组为30.00±5.50天。运用VSD治疗和常规治疗创面愈合时间比较有统计学意义(P0.05)。结论:VSD治疗兔骨外露缺损创面能有效缩短创面愈合时间,促进血管再生,胶原蛋白合成。     

三种兔单肺通气模型的比较

目的采用三种方法建立兔单肺通气模型并比较其效果。方法日本大耳白兔30只,随机分为3组(即A、B、C组)各10个,分别采用自制双腔气管导管法、左主支气管结扎法和插管过深法。呼吸机通气参数为:FiO21.0,RR 40/min,VT 10 mL/kg。单肺通气2 h后恢复双肺通气。记录各组单肺通气实施的一次成功率、总成功率、从气管切开开始到单肺通气实施所需要的时间、动物失血量。实验结束后开胸测量兔气管、左主支气管、右主支气管的长度和内径。结果各组进入实验的动物数分别为10、6、8只。与B、C组比较,A组一次成功率和总成功率高,所需时间明显较少(P<0.01),且出血量明显少于B组(P<0.01)。结论采用自制双腔气管导管能迅速有效的建立单肺通气模型,是用于研究与单肺通气相关病理生理机制的理想模型。     

七氟醚对脑缺血再灌注损伤大鼠认知功能及海马S100β及PGRN表达的影响

摘要 目的：探索用七氟醚预处理后脑缺血再灌注损伤大鼠的认知功能变化情况以及海马细胞内钙结合蛋白（S100β）及颗粒蛋白前体（Progranulin,,PGRN）的表达水平。方法：选取SPF级雄性大鼠36只,按照随机数字表法分为假手术组（A组）、脑缺血再灌注损伤组（B组）、七氟醚预处理组（C组）,每组12只。B组和C组大鼠采用线栓法建立脑缺血再灌注损伤模型,缺血2 h,再灌注24 h,假手术组仅切开不插入线栓。术前七氟醚预处理组大鼠吸入体积分数3 %七氟醚和氧流量为2 L/min的混合气体,持续1 h,假手术组和脑缺血再灌注损伤组单纯吸入2 L /min的氧气。建模完成后采用大鼠神经功能缺损评分（modified neurological severity score,mNSS）评估大鼠的神经功能状况;Morris水迷宫实验检测各组大鼠学习认知功能;Western Blot检测各组大鼠S100β和PGRN的表达情况。结果：（1）B、C组大鼠mNSS评分显著高于A组,C组评分较B组有明显降低（P＜0.05）;（2）与A组相比B、C两组逃逸潜伏期明显延长,C组与B组相比逃逸潜伏期显著缩短（P＜0.05）;（3）B、C组大鼠海马S100β和PGRN的表达较A组有显著上调,其中C组S100β表达较B组显著降低,PGRN表达显著升高（P＜0.05）。结论：本文通过观察七氟醚预处理对CIRI大鼠认知功能及海马S100β和PGRN蛋白表达水平的影响,发现七氟醚预处理对CIRI大鼠认知功能有显著提高,其作用机制与海马S100β和PGRN的表达密切相关,为进一步探索其作用机制提供参考证据。     

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