扩散性抑制对脑缺血后海马迟发性神经元死亡的影响

目的为了研究阻断大鼠局灶性脑缺血诱导的扩散性抑制对同侧海马迟发性神经元死亡的影响。方法颈内动脉插线法制备大鼠大脑中动脉缺血再灌注模型,采用电生理学方法记录扩散性抑制波,尼氏染色和TUNEL染色检测海马迟发性神经元死亡;观察阻断局灶性脑缺血再灌注诱导的扩散性抑制对海马迟发性神经元死亡的影响。结果不给予SD阻断剂,大脑中动脉缺血模型有39%的动物出现海马迟发性神经元死亡;用MK-801阻断扩散性抑制后仅10%的动物出现海马迟发性神经元死亡,机率明显减小。结论局灶性脑缺血引起的海马迟发性神经元死亡可能与扩散性抑制由缺血区不断向远隔部位播散有关。     

弥散加权成像联合磁共振波谱分析在脑梗死中的应用研究

目的探讨脑梗死弥散加权成像（DWI）和磁共振波谱分析（MRS）的特点和影响因素,及二者对评估脑梗死的临床价值。方法采用Philips Achieva 1.5T双梯度超导磁共振扫描仪,对72例临床疑是脑梗死患者行常规T1WI、T2WI、FLAIR、DWI、MRS检查,在工作站上测定梗死核心区、内缘区、外缘区、周围区和镜像区的ADC值和代谢物Lac、NAA、Cr、Cho、NAA/Cr、Lac/Cr、Lac/NAA值。结果 DWI显示的梗死灶范围较常规MRI像更加准确、清晰;超急性期、急性期、亚急性期和慢性期梗死核心区的Lac/Cr值和Lac/NAA值高于对侧镜像区,ADC值和NAA/Cr值低于对侧镜像区,存在统计学差异（P〈0.05）;DWI的影响因素有b值、扩散系数、T2穿透效应和各向异性等,MRS的影响因素有磁场均匀性、压水压脂性能、体素、TE与TR、组织代谢物浓度和波谱采集链等。结论 DWI结合MRS能更加全面地评估缺血半暗带,更精确地对脑梗死进行分期和定位。     

持续癫痫样放电导致海马神经元钙离子动力学变化的研究

目的：研究低镁介质致痫的培养海马神经元癫痫模型中神经元内游离钙离子（[Ca^2＋]i）的时空分布及其动力学改变,以探讨钙离子在癫痫发病过程中的作用。方法：联合应用共聚焦激光扫描显微镜和膜片钳,运用较高时间分辨率动态观察培养海马神经元癫痫模型[Ca^2＋]i和电生理变化,以及化学门控钙离子通道阻滞剂的影响。结果：致痫后海马神经元胞浆和核内游离钙离子迅速上升到（612±65）nmol／L和（620±69）nmol／L水平,NMDA受体阻断剂MK-801（10μmol／L）和非NMDA受体阻断剂NBQX（10μmol／L）可使[Ca^2＋]i的升高明显减少;升高的[Ca^2＋]i恢复有明显的延迟现象,90min和150min癫痫样放电后[Ca^2＋]i恢复的时间分别为（114．8±5．2）和（135．0±22．7）（P〈0．05）。结论：持续的癫痫样放电可导致海马神经元细胞内钙超载,这个效应可被MK-801阻断,化学门控钙离子通道也参与了细胞外Ca^2＋内流的过程。     

蝎毒耐热蛋白对大鼠海马神经元钠通道的抑制作用

应用全细胞膜片钳技术观察蝎毒耐热蛋白（scorpion venom heat resistant protein,SVHRP）对急性分离大鼠海马神经元电压依赖性钠通道的影响。结果表明,急性分离大鼠海马神经元产生的河豚毒素（tetrodotoxin,TTX）敏感的电压依赖性钠电流被SVHRP浓度依赖性地抑制,半数抑制浓度为（0．0034±0．0004）μg／mL,Hill常数为0．4361±0．0318;SVHRP可使钠通道稳态激活曲线向电压的正方向移动,正常TTX敏感的钠通道的半数激活电压（V1/2）为（-34．38±0．62）mV（n=16）,给予0．1μg／mL的SVHRP后V1/2为（-23．96±0．41）mV（n=8,P〈0．05）,斜坡因子（κ）由正常的4．52±0．52变为3．73±0．08（n=8,P〈0．05）。SVHRP亦能改变电压依赖性钠通道的稳态失活曲线,使其向电位的负方向移动,SVHRP处理前钠通道半数失活电压（V1/2）为（-32．60±1．52）mV,κ为6．73±0．51（n=16）;0．1μg／mL的SVHRP处理后V1/2变为（-50．69±2．55）mV（n=8,P〈0．01）,κ为5．49±0．72（n=8,P〈0．05）。结果提示,SVHRP能抑制电压依赖性钠电流,改变钠通道的动力学特性,抑制其激活,促进其失活,从而影响神经元的兴奋性,这可能是其抗癫痫的机制之一。     

异丙酚对全脑缺血倡灌注大鼠海马iNOS表达的影响

目的：观察异丙酚对全脑缺血／再灌注大鼠海马神经元诱导型一氧化氮合酶（iNOS）表达的影响,探讨异丙酚对迟发性脑神经元损伤保护作用机制。方法：采用Pulsinelli-Brierley四血管阻断法制备全脑缺血模型。全脑缺血20rain再灌注24h后断头取脑,采用Western blot方法检测大鼠海马iNOS的蛋白表达。结果：与缺血／再灌注组相比较,异丙酚处理组大鼠海马iNOS蛋白表达明显降低,存活的神经元数目明显增加,统计结果差异均有显著性（P〈0.05或0.01）。结论：异丙酚通过抑制iNOS蛋白表达对大鼠脑迟发性神经元损伤起保护作用。     

环加氧酶-2抑制剂尼美舒利通过改善内皮功能和增加NO含量对抗大鼠心肌氧化应激损伤

本文旨在研究冠状动脉内皮和NO在选择性环加氧酶2（cyclooxygenase2,COX-2）抑制剂尼美舒利（nimesulide）对抗心肌氧化损伤中的作用。离体大鼠心脏行Langendorff灌流,给予H2O2（140Bmol／L）观察心脏收缩功能。用U-46619灌流心脏,使冠状动脉预收缩后,观察冠状动脉对内皮依赖性舒张因子5-HT和内皮非依赖性舒张因子硝普钠（sodiumnitroprusside,SNP）的反应。结果显示：（1）与空白对照组（100％）相比,H202灌流20min后,左心室发展压[left ventriculardevelo pedpressure,LVDP,（54．8±4．0）％],和心室内压最大变化速率【±dp／dtmax（50．8±3．1）％和（46．2±2．9）％]明显降低。H2O2灌流前尼美舒利（5μmol/L）预处理10min,能够显著抑制H2O2引起的LVDP和μdp/dtmax下降[（79．9±2．8）％,（80．3±2．6）％和（81．4±2．6）％,P〈0．0l]。（2）与空白对照组相比,H2O2灌流后,5-HT和SNP引起内皮依赖性和内皮非依赖性血管舒张功能均明显下降;而尼美舒利预处理10min能明显对抗内皮依赖性血管舒张功能的下降[（-22．2±4．2）％vsH2O2组（-6．0±2．5）％,P〈0．0l],但对其内皮非依赖性血管舒张功能的下降没有明显作用[（-2．0±1．8）％vsH202组（-7．0±3．5）％,P〉0．05]。（3）一氧化氮合酶（nitric oxide synthase,NOS）抑制剂L-NAME能够部分取消尼美舒利预处理对H20,应激心脏心功能指标的改善作用ILVDP和±dp/dtmax分别为（60．2±2．1）％,（63．9±2．4）％和（63．1±2．9）％,P〈0．01]。同时尼美舒利预处理10min能使H202应激心肌NO含量增加[（2．63±0．40）vs（1．36±0．23）nmol／gprotein,P〈0．051,而L-NAME抑制此作用。（4）选择性COX-1抑制剂吡罗昔康（piroxicam）预处理不能抑制H202引起的LVDP和±dp/dtmax下降,但促进左心室舒张末压（1eftventricular end diastolicpressure,LVEDP）升高;吡罗昔康对H202引起的内皮依赖性和内皮非依赖性血管舒张功能下降无显著作用。以上结果提示,选择性COX-2抑制剂尼美舒利能够对抗大鼠离体心肌氧化应激损伤,其机制可能是通过改善内皮依赖性血管舒张功能和增加心肌NO含量起作用。     

欧洲小叶椴的胚培养与快速繁殖

1植物名称欧洲小叶椴（Tilia cordata Mill．）。 2材料类别成熟胚。 3培养条件（1）／3动培养基：MS＋6-BA2．0mg·L^-1（单位下同）＋NAA0．1;（2）增殖培养基：MS＋6．BA1．0＋NAA0．1;（3）壮苗生根培养基：1／2MS＋IBA1．0＋NAA0．3。以上培养基均加入0．55％琼脂和20g·L^-1。蔗精,pH5．8-6．0。培养温度为（25±2）℃;光照培养时间12h·d^-1,光照强度40．50μmol·m^-2·s^-1。     

鞘内注射U0126对吗啡戒断大鼠脊髓神经元磷酸化CREB表达的影响

目的：研究鞘内注射细胞外信号调节激酶（ERK）抑制剂U0126对吗啡依赖大鼠纳洛酮催促戒断反应、脊髓磷酸化cAMP反应元件结合蛋白（p-CREB）表达的影响。方法：建立大鼠吗啡依赖和戒断模型,分为正常对照组、吗啡依赖组、吗啡戒断组、U0126组、溶媒（DMSO）组,采用行为学（n=8）、免疫组织化学（n=6）和Western blot（n=4）方法观察鞘内应用U0126对吗啡依赖大鼠纳洛酮催促戒断反应、脊髓p-CREB表达的影响。结果：①鞘内注射u0126可明显减轻吗啡依赖大鼠戒断症状,戒断组戒断症状评分为28．6±4．89,U0126组为22．5±4．09（P〈0．05）;戒断组促诱发痛评分（TEAscore）为13．5±2．55,U0126组为10．0±2．76（P〈0．05）。②鞘内注射U0126可明显减少胸腰段脊髓背角p-CREB阳性神经元的数目,U0126组为287±54,低于戒断组（380±71,P〈0．05）。 ③westem blot结果显示：鞘内注射U0126明显抑制吗啡戒断期间脊髓p-CREB表达的增加。结论：鞘内注射U0126能明显抑制吗啡戒断大鼠脊髓神经元p-CREB的表达。     

阻断缝隙连接对脑缺血后海马迟发性神经元凋亡的影响

目的探讨阻断缝隙连接(gap junction)通讯对大鼠局灶性脑缺血后海马迟发性神经元死亡(delayed neuronal death,DND)及Bcl-2蛋白表达的影响。方法术前2h左侧脑室注射缝隙连接阻断剂甘珀酸(carbenoxolone,CBX),对照组左侧脑室注射生理盐水,颈内动脉插线法制备大鼠大脑中动脉缺血再灌注模型,采用DNA原位末端标记TUNEL技术及免疫荧光技术,观察阻断缝隙连接对大鼠局灶性脑缺血3d后海马迟发性神经元死亡及BCL-2蛋白表达的影响。结果不给予缝隙连接阻断剂,大脑中动脉缺血模型有45%的大鼠在术后3d出现海马迟发性神经元死亡;用甘珀酸阻断缝隙连接后,30%的大鼠出现海马迟发性神经元死亡,其发生率明显减小(P<0.01);与对照组相比,干预组Bcl-2蛋白的表达较高(P<0.01),两组Bcl-2蛋白的表达均高于假手术组(P<0.01)。结论阻断缝隙连接通讯可以减少局灶性脑缺血后海马迟发性神经元死亡的发生率,Bcl-2参与了局灶性脑缺血后海马神经元凋亡的调节。     

线粒体通透性转换孔在缺血预处理脑保护中的作用及机制

目的：线粒体通透性转换孔通透性改变是导致缺血再灌注损伤的原因,线粒体功能的致命性改变最终引起细胞凋亡,本研究旨在观察线粒体通透性转换孔（mitochondrial permeability transition pore,MPTP）在缺血再灌注及缺血预处理脑保护中的作用;方法：将体外培养8天的海马神经元细胞分为五组,正常对照组（A组）,缺血再灌注组（B组）,缺血预处理＋缺血再灌注组（C组）,苍术苷＋缺血再灌注组（D组）,缺血预处理＋苍术苷＋缺血再灌注组（E组）。使用流式细胞术检测各组细胞凋亡率,罗丹明123染色流式细胞术检测线粒体膜电位,Western-blot检测Bcl-2,Bax的表达。结果：与A组比较,其余四组线粒体膜电位均降低,神经元凋亡率升高（P〈0．05）;与B组比较,c组线粒体膜电位升高,神经元凋亡率升高,Bcl-2表达上调,Bax表达下调（P〈0．05）;与c组比较,E组粒体膜电位降低,神经元凋亡率升高,Bcl．2表达下调,Bax表达上调（P〈0．05）。结论：我们在细胞及分子生物学水平对MPTP及缺血预处理的研究后发现,缺血预处理能有效减轻海马神经元缺血再灌注损伤,抑制缺血再灌注后神经细胞凋亡,其机制与抑制MPTP的开放有关。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

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     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.