白血病抑制因子与哺乳动物的胚胎着床(英文)

胚胎着床是处于活化状态的胚泡与处于接受态的子宫相互作用,最后导致胚胎滋养层与子宫内膜建立紧密联系的过程。已证实白血病抑制因子(LIF)在哺乳动物胚胎着床过程中起着十分重要的调节作用。LIF通过其受体及信号传递亚单位gp130发挥其生物学功能。LIF对胚胎发育到胚泡阶段及以后内细胞团和滋养层细胞的生长和分化有明显的促进作用。 在小鼠中,LIF及其受体和gp130在着床期小鼠子宫内表达量最高,因此LIF可能在小鼠胚胎着床过程中起重要作用。在人中,LIF在子宫内膜中的表达与人胚胎着床的时间一致,提示LIF可能与人的胚胎着床紧密相关。此外,LIF在猪、羊、水貂、兔和臭鼬等动物胚泡着床前和着床期的子宫中也都有表达,并在着床期出现峰值。因此,LIF也可能在这些动物的胚胎发育和着床过程中有重要作用。LIF受体基因敲除小鼠表现为胎盘发育不全,这说明LIF对小鼠胎盘形成和胎盘的功能维持起重要作用。 小鼠子宫中LIF的表达可能受雌激素而上调。美洲长尾猴(绒)及兔子宫中LIF的表达则呈孕酮依赖性。然而孕酮可抑制人着床期子宫内膜腺上皮和蜕膜组织内LIF的表达。在不同种类的动物中,LIF在子宫中的表达有不同的调节机制。 胚泡在LIF基因敲除的雌鼠子宫内不能着床的原因并不是由于胚泡发育异常,而是由于雌鼠不能表     

妊娠早期胚泡、子宫液和子宫内膜的蛋白质及其与着床的关系

哺乳动物胚泡着床是涉及胚泡和子宫内膜之间的相互作用问题,研究着床机理或从着床途径考虑控制生育,可从如何抑制胚泡着床能力或改变子宫内膜使其不适于胚泡着床的条件着手。近年来,有关这两方面的研究已积累了不少资料,特别是蛋白质分析技术的发展。许多研究者报道了在各种动物早期妊娠过程中,随体内激素水平的变化,子宫液(包括子宫内膜和胚泡)蛋白质或小肽物质有量和种类的细微变化,这些变化关系到母体对妊娠的识别、胚泡与子宫的粘附和胚泡的侵入。     

妊娠早期胚泡、子宫液和子宫内膜的蛋白质及其与着床的关系

哺乳动物胚泡着床是涉及胚泡和子宫内膜之间的相互作用问题,研究着床机理或从着床途径考虑控制生育,可从如何抑制胚泡着床能力或改变子宫内膜使其不适于胚泡着床的条件着手.近年来,有关这两方面的研究已积累了不少资料,特别是蛋白质分析技术的发展.许多研究者报道了在各种动物早期妊娠过程中,随体内激素水平的变化,子宫液(包括子宫内膜和胚泡)蛋白质或小肽物质有量和种类的细微变化,这些变化关系到母体对妊娠的识别、胚泡与子宫的粘附和胚泡的侵入.     

促黄体素释放激素类似物(LH-RH-A)对妊娠大鼠子宫代谢的直接作用

本实验结果表明,胚泡着床点对~3H-尿嘧啶和~3H-亮氨酸的摄取明显高于非着床点子宫部位。LH-RH-A可显著抑制胚泡着床点对这两种同位素的摄取;且对非着床子宫组织也有抑制作用,但抑制程度较弱。进一步证实,着床的胚泡确能产生一种或几种因子,对子宫内膜的分化起重要作用;同时证实,LH-RH-A可通过对RNA和蛋白质合成的抑制作用而直接影响妊娠大鼠子宫的代谢,对胚泡着床点部位的影响尤为明显。     

白血病抑制因子对胚泡金属蛋白酶表达的影响

为了探讨白血病抑制因子 (LIF) 对胚泡着床作用的机理,胚泡经与LIF及其特异性抗体培养后,通过RT-PCR及免疫印迹技术,分析了LIF与着床前小鼠胚泡的基质金属蛋白酶9(MMP9)表达和分泌之间的关系.结果显示：LIF可明显诱导胚泡MMP9的分泌和基因表达; 经LIF特异性抗体封闭后,胚泡MMP9的分泌及基因表达下降,且下降趋势随着LIF被封闭时间延长而减弱,对MMPs组织抑制因子1(TIMP1)的影响则不明显.说明LIF可能通过诱导MMP9的分泌及基因表达来影响胚泡对子宫内膜细胞外基质的水解,促进着床.     

哺乳动物胚泡着床及影响因素

哺乳动物胚泡着床是生殖过程中的关键环节。受精卵经过早期发育形成了胚泡，胚泡脱去透明带后，经定位、粘附、滋养层侵入，植入到子宫内膜中，同时母体子宫内膜发生蜕膜化控制植入的程度，最终完成着床过程。着床过程受多种因素的影响，主要因素有：母体子宫内膜和胚泡发育的同步化，母体的激素环境，胚泡分泌的激素，母体子宫的接受性及局部免疫保护作用。     

PTEN在早孕小鼠子宫内膜的表达及其对胚泡着床的影响

本研究旨存检测肿瘤抑制基因PTEN(phosphatase andtensinhomologdeletedonchromosometen)在早孕小鼠子宫内膜中的表达规律,探讨PTEN在小鼠胚胎着床过程中的作用.采用实时荧光定量聚合酶联反应(real.time fluorescent quantitative PCR.FQ.PCR)和免疫组织化学方法分别检测未孕及孕1、3、4、5、7 d小鼠子宫内膜PTEN mRNA和蛋白的表达;子宫角注射PTEN反义寡核苷酸观察胚泡着床数.FQ-PCR结果显示,妊娠小鼠子宫内膜组织PTENmRNA的表达高于未妊娠小鼠,且随着妊娠天数的增加表达逐渐增强,到妊娠第5天达最高.免疫组织化学分析显示,PTEN蛋白在子宫内膜的表达规律与mRNA结果一致.子宫角注射PTEN反义寡核苷酸后胚泡着床数明显减少.结果提示,PTEN在妊娠早期子宫内膜持续表达,可能参与了胚泡着床.     

半夏蛋白的抗兔胚泡着床作用

半夏蛋白有很强的抗兔胚泡着床作用,子宫内注射500μg,抗着床率达100%。经半夏蛋白作用后的子宫内膜能使被移植的正常胚泡不着床。在子宫内经半夏蛋白孵育的胚泡移植到同步的假孕子宫,着床率随孵育时间延长而降低。用辣根过氧化物酶标记半夏蛋白的定位实验表明该蛋白结合在子宫内膜腺管的上皮细胞膜上。已知半夏蛋白有类似凝集素的活性,能与甘露聚糖结合,它的抗着床作用可能是由于该蛋白结合了母体和(或)子体细胞膜上的某些糖结构,改变了细胞膜的生物学行为所致。     

着床期小鼠子宫内膜Le~y糖蛋白的动态变化

为了解子宫内膜Ｌｅ~ｙ糖蛋白在胚泡着床期间的变化,以及与胚泡表面阶段特异性Ｌｅ~ｙ抗原出现的关系,应用对Ｌｅ~ｙ寡糖特异的ＡＨ－６单抗为探针,通过ＳＤＳ－ＰＡＧＥ和Ｗｅｓｔｅｒｎｂｌｏｔ免疫酶标染色,观察了小鼠子宫内膜Ｌｅ~ｙ糖蛋白在着床期的动态变化和分布特点。结果表明：（１）未孕及着床前后的小鼠子宫内膜均含Ｌｅ~ｙ糖蛋白Ｍｒ５０～２００ｋＤ）,未孕内膜的含量明显高于着床期间的样品;（２）在着床日（Ｄ４）样品可见微量１６ｋＤ的Ｌｅ~ｙ糖蛋白条带;（３）未孕至Ｄ４的子宫内膜均有Ｌｅ~ｙ糖蛋白分泌至宫腔,但呈渐减趋势,未孕样品Ｌｅ~ｙ糖蛋白主要为分泌型,而Ｄ４样品Ｌｅ~ｙ糖蛋白主要存在于子宫内膜,宫腔液含量很少;结果提示子宫内膜Ｌｅ~ｙ糖蛋白在着床期间具有含量、组成和分布上的动态变化,这些变化可能与胚泡着床以及胚泡在宫腔内其表面Ｌｅ~ｙ糖抗原转为阳性密切有关。     

着床期家兔子宫内膜糖蛋白的动态研究

本文以~3H-glucosamine(~3H-GlcNH_2)为前体,观察了着床期家兔子宫内膜糖蛋白的生物合成及分泌功能的变化,并利用Triton X-100提取膜蛋白,采用凝集素亲和电泳技术对三种不同性质糖蛋白进行了动态分析。结果表明,着床期家兔子宫内膜糖蛋白的合成与分泌功能均于妊娠第六天(D_6)明显增强,其中合成糖蛋白的变化以Triton溶解蛋白部分为主;井发现着床期WGA、RCA-Ⅰ、SBA结合蛋白均于着床前(D_6)明显增加,着床后(D_9)WGA结合蛋白略有降低,RCA-Ⅰ、SBA结合蛋白明显降低,接近未孕水平。着床期子宫内膜总体及不同种类糖蛋白的阶段特异性变化表明,在子宫内膜由对胚泡的非接受状态转变为接受态的过程中,阶段特异性糖蛋白可能具有重要作用。     

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.