槲皮素对谷氨酸诱导的PC12细胞损伤的保护作用及对海马CA1锥体神经元钾通道的影响(英文)

槲皮素广泛存在于许多药用植物中,属黄酮类化合物,在临床上常用于心血管疾病的治疗。采用四甲基偶氮唑盐比色法(MTT法)及DAPI染色,研究槲皮素(0.5、1、5、10μmol/L)对谷氨酸(10mmol/L)诱导的PC12细胞损伤作用的影响;并进一步研究槲皮素(0.3、3、30μmol/L)对急性分离的海马CA1锥体神经元离子通道的作用。MTT实验结果显示,槲皮素可提高谷氨酸处理组PC12细胞的存活率,并呈现为浓度和时间依赖性(P0.05);而槲皮素(5μmol/L)与谷氨酸(10mmol/L)共孵育PC12细胞后,DAPI染色结果表明槲皮素可减弱谷氨酸对PC12细胞的损伤。对电生理结果显示,槲皮素对瞬时外向钾电流(IA)和延迟整流钾电流(IK)有显著的抑制作用(P0.05),表现为浓度依赖性。以上结果提示,槲皮素可能通过抑制海马锥体神经元的外向钾电流进而对谷氨酸诱导的神经损伤起保护作用,这也说明了槲皮素对缺血样损伤的神经具有保护作用。     

三氯化铝对大鼠海马CA1区锥体细胞瞬间外向钾电流和延迟整流钾电流的影响

采用全细胞膜片钳技术,研究了三氯化铝(AlCl3)对急性分离的大鼠海马CA1区神经元钾通道的影响。结果表明,AlCl3对钾电流有明显的抑制作用,具有一定的浓度依赖性,1000μmol／AlCl3可改变IA和IX激活曲线和失活曲线的Vb和k值,使钾电流激活曲线右移,使失活曲线左移。这些结果表明AlCl3对大鼠海马CA1区神经元K^ 通道有抑制作用,它可能是铝引起中枢神经系统损伤的机制之一。     

皮质酮对原代培养海马神经元的毒性作用及NMDA受体亚基表达的改变

目的研究皮质酮对大鼠海马神经元的毒性作用及NMDA受体亚基表达的影响.方法以体外原代培养的大鼠海马神经元为研究对象,根据影响因素,即给予的不同浓度皮质酮和其它因素分为8个组:对照组、10-7mol/L皮质酮组(简称10-7组)、10-6mol/L皮质酮组(简称10-6组)、10-5mol/L皮质酮组(简称10-5组)、10-6 高糖组、10-5 高糖组、10-6mol/L MK801组和10-5mol/L MK801组,镜下观察不同浓度皮质酮作用下海马神经元形态学的变化,并采用MTT方法测量各组细胞存活率,利用免疫细胞化学结合图象分析对原代培养海马神经元NMDA受体亚基的表达进行观察.结果 10-6、10-5浓度的皮质酮对海马神经元影响较大,细胞存活率较对照组明显降低,但10-6 高糖组、 10-5mol/L 高糖组、10-6mol/L MK801及10-5mol/L MK801 4个组,分别与相同皮质酮浓度处理组比较,细胞存活率显著提高.10-6和10-5组海马神经元上NMDA受体亚基表达较对照组明显降低.10-7mol/L浓度的皮质酮对上述指标影响不大.结论过量的皮质酮对大鼠海马神经元具有损伤作用,NMDA受体参与了此过程,NMDA受体拮抗剂和高浓度葡萄糖可保护海马神经元.     

脑益康药物血清对谷氨酸诱导海马神经元损伤的保护作用

目的:探讨脑益康药物血清对谷氨酸(Glu)诱导的海马神经元损伤的保护作用。方法:大鼠海马神经元培养后,采用形态学观察、MTT法及DAPI染色法检测脑益康药物血清对Glu损伤细胞活力的影响,采用RT-PCR和免疫组化方法检测脑益康药物血清对Glu损伤细胞PTEN表达的影响。结果:脑益康药物血清可明显提高Glu损伤的海马神经元的细胞活力,减少PTEN的表达。结论:脑益康药物血清对Glu诱导的海马神经元损伤有保护作用,其机制可能与减少PTEN表达,抑制神经元凋亡有关。     

川芎嗪对Aβ25-35诱导体外大鼠海马神经元细胞凋亡的影响

本文通过Aβ25-35诱导体外原代培养的SD乳大鼠海马神经元,建立Aβ毒性损伤细胞模型,结合AnnexinV-FITC/PI荧光双染法流式细胞术、MTT比色法、实时荧光定量PCR及Western blot方法检测川芎嗪(tetrameth-ylpyrazine,TMP)对原代培养的海马神经元细胞活性、早期凋亡率和Bax、Bcl-2基因表达的影响。结果显示川芎嗪高、中剂量可明显增强细胞活性,增加神经元细胞的存活率(P<0.01),可显著抑制海马神经元细胞早期凋亡(P<0.01),抑制凋亡蛋白Bax的表达(P<0.01),增强抗凋亡蛋白bcl-2的表达(P<0.01)。川芎嗪可通过调节Bax/Bcl-2平衡抵抗Aβ25-35诱导的海马神经元凋亡,降低Aβ的神经元毒性,对海马神经元损伤有明显的保护作用。     

海马脑片锥体神经元钙离子通道的盲法膜片钳研究

目的和方法 :采用大鼠海马脑片盲法膜片钳全细胞记录技术研究CA1区锥体神经元电压门控性Ca2 通道的动力学特征。结果 :大鼠海马脑片CA1区锥体神经元电压门控性Ca2 通道电流具有如下特点 :①激活的阈电位偏低 ,为 (- 4 9.3± 8.6 )mV ,范围为 - 6 5～ - 30mV(n =2 3)。②衰减时间常数τ值较大 ,且变化范围大 (10 0～ 70 0ms) (n =12 ) ,并且衰减具有Ca2 电流幅值的依赖性 ,③稳态失活呈现电压依赖性 ,半失活电压为 (- 5 5 .4± 9.7)mV ,斜率因子为 (5 .3± 0 .9)mV(n =10 )。④当细胞外Ca2 浓度为 2 .5mmol/L时 ,Ca2 通道的反转电位为 (5 5±13)mV(n =10 )。⑤尾电流成分较为单一 ,不表现电压依赖性。另外 ,Ca2 电流对戊脉胺及双氢吡啶类化合物硝苯地平均不敏感。结论 :根据上述Ca2 电流特征 ,海马脑片CA1区锥体神经元上的Ca2 通道主要以N型为主     

KATP通道对缺氧海马CA1区神经元损伤保护作用的机制

目的:探讨KATP通道在缺氧中对海马CA1区神经元的保护作用机制。方法:比较对照组、单纯缺氧组、KATP通道激动剂 缺氧组、KATP通道阻断剂 缺氧组中神经元p53 mRNA的表达、DNA断裂、以及神经元存活情况。结果:将神经元暴露在氧浓度为0%的缺氧环境中12h,KATP通道的激动剂二氮嗪(diazoxide,100μmol/L)显著降低p53 mRNA的表达量及细胞的凋亡数量。KATP通道的阻断剂甲糖宁(tolbutamide,100μmol/L)使p53mR-NA表达量显著增加,细胞的凋亡数量也随之显著增加。p53的特异性阻断剂曲古抑菌素(trichostatin,TSA)可以逆转甲糖宁(tolbutamide,100μmol/L)的作用。结论:KATP通道可以通过下调p53 mRNA的表达水平,对缺氧中的海马CA1区神经元起到保护作用。     

蝎毒耐热蛋白对红藻氨酸诱导的海马NPY能神经元损伤的影响

目的:观察蝎毒耐热蛋白(SVHRP)对红藻氨酸(KA)诱导的原代培养海马神经肽Y(NPY)能神经元损伤的影响及其可能的分子机制。方法:制备原代培养10d的大鼠海马神经元并用神经元特异性MAP-2抗体进行鉴定,将鉴定成熟的神经元用终浓度为20μg/ml的SVHRP和10μmol/L的KA处理,共孵育24h后,分别用硫堇染色、MTT实验检测不同给药组残存神经元的数目和活力,用免疫细胞化学和RT-PCR技术检测NPY-IR和NPYmRNA的表达。结果:MAP-2-IR结果显示85%以上为阳性成熟神经元;硫堇染色显示,同模型组比较,模型给药组未见神经元形态异常,并且神经元数目未见明显减少(P<0.05);MTT实验显示,模型给药组海马神经元存活率较模型组明显增高(P<0.05);NPY-IR检测表明,模型组NPY阳性细神经元数目明显减少,模型给药组NPY阳性神经元数目明显多于模型组(P<0.01);RT-PCR实验表明,单独给药组海马神经元内NPYmRNA表达较其他三组明显增多(P<0.05)。结论:SVHRP对KA诱导的原代海马神经元的兴奋毒性损伤具有明显的保护作用,可能与SVHRP促进NPY合成有关。     

硫化氢减轻同型半胱氨酸诱导大鼠海马CA1区神经元损伤

目的探讨硫化氢(H2S)对同型半胱氨酸(Hcy)诱导大鼠海马CA1区神经元损伤的改善作用。方法以侧脑室注射同型半胱氨酸的SD大鼠为同型半胱氨酸神经毒性动物模型,采用Tunel染色法分析大鼠海马CA1区神经元的凋亡情况,采用Elisa法分析大鼠海马组织MDA含量。结果 0.6μmol和2.0μmol的同型半胱氨酸使大鼠海马CA1区神经元发生大量的凋亡(P0.01),而NaHS(100μmol/kg)显著抑制同型半胱氨酸(0.6μmol)诱导大鼠海马CA1区神经元的凋亡(P0.05);同型半胱氨酸(0.2,0.6μmol)可增加大鼠海马CA1区丙二醛含量(P0.001),而NaHS(100μmol/kg)可抑制同型半胱氨酸(0.6μmol/L)诱导大鼠海马CA1区丙二醛水平的增加(P0.001)。结论硫化氢可减轻同型半胱氨酸诱导大鼠海马CA1区神经元的损伤。     

电磁脉冲辐照大鼠海马区细胞凋亡与形态学变化

以体外原代培养的大鼠海马神经元和Wistar大鼠为研究对象,探讨电磁脉冲(场强为6× 104 V/m)辐照后早期海马区细胞凋亡和病理形态学的变化.在照射后1h、6h、12h、24h和48h分别采用MTT法和流式细胞仪测定死亡细胞和凋亡细胞的比例,用光镜和电镜分别进行形态学观察.结果显示在电磁脉冲辐照后,海马神经细胞不仅发生快速的坏死,而且还发生凋亡,同时在早期即可见到血管、胶质细胞和神经元等组织的形态学异常.表明大鼠大脑受电磁脉冲辐照后早期海马区可发生神经细胞坏死和凋亡,以及各组织成分的病理形态学改变,上述变化可能与电磁脉冲致细胞DNA损伤有关.     

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.