鼻咽上皮细胞的调节性容积回缩能力及机制

用图像分析系统和通道阻断法研究了原代人胎儿鼻咽上皮细胞的调节性容积回缩（regulatory volume decrease,RVD）能力及其机制。结果发现,低渗刺激可诱发鼻咽上皮细胞产生RVD,在160-240 mOsmol／L范围内,RVD强弱与渗透压呈“S”形负相关（r=-0．99,P〈0．05）,与细胞肿胀程度呈“S”形正相关（r=0．99,P〈0．05）。Cl-通道阻断剂tamoxifen（20μmol／L）,ATP（10mmol／L）或NPPB（100μmol／L）对RVD阻抑率分别为100％（P〈0．01）,76．3％（P〈0．01）和62．7％（P〈0．01）。本研究表明,鼻咽上皮细胞受到低渗刺激时可产生RVD,Cl-通道开放是其RVD的关键机制。     

低渗条件下小肠上皮细胞调节性细胞容积减小的离子通道机制

目的:观察人小肠上皮细胞调节性细胞容积减小(RVD)的过程,探讨参与RVD过程的离子通道机制.方法:将培养的人小肠上皮细胞暴露于低渗溶液, 利用电子细胞体积测量系统测定细胞平均容积变化过程和离子通道的参与过程;采用RT-PCR方法检测人小肠上皮细胞上离子通道的表达.结果:人小肠上皮细胞具有良好的RVD功能; 其RVD过程可被氯通道阻断剂NPPB 和钾通道阻断剂四乙铵所阻断; 进一步的研究发现, 中等电导钙激活性钾通道(IK)的特异性阻断剂Clotrimazole (CLT) (1μmol/L)可以明显抑制细胞的RVD过程,而大电导钙激活性钾通道(BK)和小电导钙激活性钾通道(SK)的特异阻断剂iberiotoxin (100 nmol/L)和apamin (100 nmol/L)对RVD过程无任何抑制作用.RT-PCR的结果也显示, 人小肠上皮细胞只有IK表达, 而无SK和BK的表达.结论:人小肠上皮细胞具有RVD功能,RVD过程的完成有赖于氯通道和钾通道的平行激活, 而其中参与容积调节的钾通道是中等电导钙激活型钾通道IK.     

白藜芦醇对猪原代前体脂肪细胞的增殖与分化及Sirt1基因转录表达时序的影响

分别以0μmol/L(对照组)、10μmol/L(低剂量组),20μmol/L(中等剂量组),50μmol/L,100μmol/L(高剂量组)的白藜芦醇(Resveratrol,RES)处理体外培养1~3日龄健康仔猪前体脂肪细胞,采用MTT比色法检测细胞活性及增殖状况;油红O染色化学比色法定量分析细胞内脂肪生成及细胞分化程度;RT-PCR法分析Sirt1(sirtuin1)mRNA表达情况,探讨Sirt1对猪前体脂肪细胞增殖分化的影响及其分子机制。结果表明,脂肪细胞经RES处理后,各组MTT和油红O染色测得的光密度值(OD值)均低于对照组,50μmol/L,100μmol/L组在96~120h作用极显著(P<0.01),与中低剂量组差异显著(P<0.05);以20μmol/L,100μmol/LRES处理细胞后,Sirt1mRNA表达量随细胞分化的进行而逐渐升高,100μmol/L组均显著高于对照组和20μmol/L组(P<0.05)。RES对猪前体脂肪细胞增殖分化均有一定抑制作用,高剂量RES(50μmol/L和100μmol/L)可显著减少细胞内脂肪的合成、抑制脂肪细胞增殖与分化,Sirt1mRNA表达量显著升高可能是RES抑制细胞分化的重要原因之一。     

HERG钾通道在细胞容量调节中的作用

目的:研究HERG钾通道在细胞容量调节中的作用,并探讨其作用机制。方法:全部试验应用稳定转染HERG-HEK293细胞和HEK293细胞。应用全细胞膜片钳技术记录HERG钾电流。结果:1当HERG-HEK293细胞处于低渗状态,指令电压为0 mV时,Istep增加60%(n=12,P0.05);如指令电压为+30 mV,Itail增加72.1%(n=11,P0.01),增大的HERG电流可被特异性HERG钾电流阻断剂Cisapride(100nM)抑制,Istep被抑制97.2%(n=6,P0.01),Itail被抑制174.1%(n=6,P0.01)。2在低渗状态,指令电压为0 mV时,容量调节性氯通道阻断剂尼氟灭酸(NFA,10 nmol/L)使Istep抑制46.2%(n=12,P0.01),Itail抑制48.5%(n=11,P0.01);给以容量调节性氯通道阻断剂DIDS 100μmol/L时,Istep抑制45.9%(n=12,P0.01),Itail抑制51.1%(n=11,P0.01)。结论:HERG通道部分参与调节性细胞容量下降过程。其参与的细胞容量调节与容量调节性氯通道的激活相伴随。     

MEK/ERK信号通路对人结膜上皮细胞增殖的影响及其机制研究

目的:探讨MEK/ERK信号通路对人结膜上皮细胞增殖的影响及其可能的机制。方法:采用不同浓度(0、12.5、25、50、100μmol/L)的MEK抑制剂PD98059处理人结膜上皮细胞(HConEpiC),通过CCK-8法检测不同浓度PD98059作用不同时间(0、12、24、48 h)对人结膜上皮细胞增殖的影响,Western blot检测不同浓度PD98059对人结膜上皮细胞ERK1/2、P-ERK1/2表达的影响。结果:相比对照组(0μmol/L),不同浓度(12.5、25、50、100μmol/L)PD98059处理后的人结膜上皮细胞增殖率明显下降,呈剂量-效应关系,且随处理时间增加(12、24、48 h)其抑制作用也显著增强,差异均有统计学意义(P0.05)。不同浓度PD98059处理人结膜上皮细胞24 h后,其ERK及p-ERK1/2表达随处理浓度增加而降低,与对照组(0μmol/L)相比差异有统计学意义(P0.05),且二者表达量与细胞增值抑制率均呈显著负相关(r=-0.995、r=-0.968,P0.05)。结论:PD98059可抑制人结膜上皮细胞增殖,这可能与其下调ERK表达和减少其活化有关。     

白藜芦醇甙对大鼠心室乳头状肌动作电位的影响及其离子机制(英文)

有研究表明白藜芦醇甙(polydatin)具有抗缺血性心律失常作用,但其电生理学机制尚未明了。本研究旨在应用细胞内记录和全细胞膜片钳方法,探讨白藜芦醇甙对大鼠心室乳头状肌动作电位的影响及其离子机制。结果显示:(1)白藜芦醇甙(50和100μmol/L)可剂量依赖性地缩短正常乳头状肌动作电位复极化50%时间(APD50)和90%时间(APD90)(P<0.01)。白藜芦醇甙对正常乳头状肌静息电位(resting potential,RP)、动作电位幅值(amplitude of action potential,APA)、超射值(overshoot,OS)和0期最大上升速度(Vmax)无影响(P>0.05)。(2)对部分去极化的乳头状肌,白藜芦醇甙(50μmol/L)不但缩短APD50和APD90,而且还降低动作电位OS、APA和Vmax(P<0.05)。(3)ATP敏感钾通道阻断剂格列本脲(10μmol/L)可部分阻断白藜芦醇甙(50μmol/L)的电生理效应。(4)一氧化氮合酶抑制剂L-NAME(1 mmol/L)对白藜芦醇甙的上述效应无影响。(5)白藜芦醇甙(25、50、75、100μmol/L)可浓度依...     

缓激肽抑制麻醉大鼠颈动脉窦压力感受器反射

在36只隔离灌流左侧颈动脉窦区的麻醉大鼠上观察了缓激肽(bradykinin,BK)对颈动脉窦压力感受器反射的影响.结果如下:(1)以BK (1.0μmol/L)隔离灌流大鼠颈动脉窦区时,压力感受器机能曲线向右上方移位,曲线的最大斜率(peak slope,PS)由0.44±0.14降至0.31±0.01(P<0.01),反射性血压下降幅度(reflex decrease,RD)由6.85±0.18 kPa降至4.46±0.16 kPa (P<0.01),阈压(TP)由7.76±0.20增至10.04±0.09kPa (P<0.05),其中RD,PS和TP的变化呈明显的剂量依赖性.(2)用环氧酶抑制剂消炎痛(indomethacin,10 μmol/L)预处理后,对BK (1.0μmol/L)抑制压力感受器的作用无影响; (3)预先灌流NO合酶阻断剂(L-NAME,100μmol/L),则可完全消除BK (1.0μmol/L)对压力感受器反射的抑制效应; (4)预先给予转换酶抑制剂(captopril,20μmol/L),可加强BK对压力感受器反射的抑制作用.以上结果表明:BK对大鼠颈动脉窦压力感受器反射有抑制作用,此作用系BK引起血管内皮细胞生成NO所致.     

瞬时感受器电位A1通道参与冷刺激引起的离体大鼠结肠平滑肌收缩(英文)

瞬时感受器电位A1(transient receptor potential A1,TRPA1)通道是一种可以被伤害性冷刺激激活的TRP家族离子通道。本研究的目的是探讨TRPA1通道是否参与冷刺激引起的大鼠结肠平滑肌收缩及其可能的机制。分离雄性Wistar大鼠升结肠和降结肠的平滑肌,制备成肌条,灌流不同温度Krebs液给予冷刺激,然后17°C冷刺激条件下用不同药物灌流,用张力换能器记录张力变化。逆转录PCR(RT-PCR)检测上述平滑肌中TRPA1、TRPM8和TRPV1的mRNA表达。结果显示,在大鼠升结肠和降结肠的平滑肌层有TRPA1的表达,但无TRPM8和TRPV1的表达。肌张力研究显示,不同温度(32、25、17、12°C)的冷刺激可以引起大鼠升结肠和降结肠纵行平滑肌的收缩,并且收缩张力随着温度降低而增强,17°C冷刺激可引起最大收缩(P0.01)。TRPA1的阻断剂钌红(30μmol/L)可以抑制冷刺激引起的升、降结肠平滑肌的收缩(P0.05)。TRPA1激动剂异硫氰酸烯丙酯(AITC,300μmol/L)和桂皮醛(CA,1mmol/L)预处理肌条后,可降低或几乎取消冷刺激引起的升结肠(P0.01,P0.05)和降结肠(均P0.001)平滑肌的收缩。去除细胞外Ca2+(EGTA,1mmol/L)、PLC阻断剂U73122(10μmol/L)、IP3受体阻断剂2-APB(30μmol/L)均可抑制17°C冷刺激引起的升、降结肠平滑肌的收缩(P0.001,P0.05,P0.001)。阿托品(1μmol/L)则对17oC冷刺激引起的升、降结肠平滑肌的收缩均无影响。L-型钙通道阻断剂硝苯地平(1μmol/L)和神经毒素河豚毒素(2μmol/L)可抑制降结肠平滑肌的收缩(P0.01,P0.05),而对升结肠没有作用。综上所述,TRPA1通道参与冷刺激引起的大鼠升结肠和降结肠平滑肌的收缩,其胞内信号转导机制可能涉及PLC/IP3/Ca2+途径的激活。另外,L-型钙通道和非M受体介导的神经机制部分参与冷刺激引起的降结肠平滑肌收缩,这可能是降结肠收缩张力大于升结肠的原因。     

TRPV4在渗透压对大鼠心肌收缩性影响中的作用

本文旨在探讨低渗和高渗内环境对心肌收缩性的影响及机制.取Sprague-Dawley(SD)大鼠左心室乳头状肌,在电刺激引起兴奋的条件下,分别记录在低渗、等渗和高渗灌流液中肌条的收缩力;同样条件下观察在低渗、等渗和高渗灌流液中加入渗透压敏感蛋白瞬时感受器电位离子通道家族香草素受体亚家族IV型(transient receptor potential vanilloid 4,TRPV4)的拮抗剂和激动剂后肌条收缩力的变化.结果显示:(1)与等渗(310 mOsm/L)时心肌收缩力相比,渗透压为290、270和230 mOsm/L时心肌收缩力分别增加11.5%、21.5%、25.O%(P<0.05);渗透压为350、370、390 mOsm/L时心肌收缩力分别降低16.0%、23.7%、55.2%(P<0.05).(2)在低渗液(270 mOsm/L)中加入TRPV4拮抗剂钌红(ruthenium red,RR),低渗对心肌收缩力的增强作用被抑制36%(P<0.01);在高渗液(390 mOsm/L)中加入RR,高渗对心肌收缩力的抑制作用增加56.1%(P<0.01).(3)在等渗液中(310 mOsm/L)加入TRPV4激动剂4-α-佛波醇-12,13-二癸酸(4-α-phorbol-12,13-didecanoate,4 α-PDD),心肌收缩力没有改变;在高渗液中(390 mOsm/L)加入4α-PDD,高渗对心肌收缩力的抑制作用增加27.1%(P<0.01).以上结果提示,TRPV4参与渗透压引起的心肌收缩力变化.     

乙型肝炎病毒B,C基因型引起的慢性乙型肝炎患者特异性、非特异性细胞免疫比较

对138例CHB患者进行HBV基因分型,检测非特异性CTL,HBV特异性CTL,肝功能,HBVDNA,HBVM(HBsAg,抗-HBs,HBeAg,抗-HBe,抗-HBc).结果显示,C基因型感染者,非特异性CTL((19.91±6.01)%)高于B基因型感染者((16.12±3.12)%),t=3.05,P<0.01,HBVDNA水平((6.25±0.81)log10拷贝/mL)高于B基因型感染者((5.02±0.61)log10拷贝/mL),t=6.03,P<0.01,HBeAg阳性46例(74.19%),高于B基因型感染者(39例,占52%),χ2=7.09,P<0.01,丙氨酸氨基转移酶(ATL)、血清总胆红素(TBIL)水平(分别为(507.15±312.17)IU/L和(46.10±40.18)μmol/L)高于B基因型感染者(分别为(290.05±215.12)IU/L和(29.12±17.12)μmol/L),t=3.76,2.29,P<0.01,P<0.05.C基因型感染者的HBV特异性CTL((0.21±0.05)%),低于B基因型感染者((0.39±0.12)%),t=5.61,P<0....     

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.