矿化液和地塞米松增强大鼠原代骨髓基质细胞NF-κB受体活化剂配体的表达

NF-κB受体活化剂配体(receptoractivatorforNF-κBligand,RANKL)是调节破骨细胞生成的重要因子,它可在骨髓基质细胞中表达。矿化液(含10-8mol/L地塞米松、10mmol/Lβ-甘油磷酸钠、50μg/mlL-抗坏血酸)能够诱导骨髓基质细胞向成骨细胞分化,为探讨矿化液及其主要成分地塞米松对大鼠原代骨髓基质细胞表达RANKL的影响,采用矿化液培养原代大鼠骨髓基质细胞48h,通过免疫荧光染色观察RANKL的表达变化。结果显示矿化液和地塞米松在短期内均能增强鼠骨髓基质细胞RANKL的表达,提示地塞米松促进破骨细胞形成的分子机制可能与骨髓基质细胞RANKL表达的改变密切相关。     

OPG/RANKL/RANK系统与骨破坏性疾病

近年来发现的OPG/RANKL/RANK系统在破骨细胞生成中起着至关重要的作用,是骨骼生理研究领域的重大进展。成骨细胞、骨髓基质细胞、激活的T淋巴细胞表达RANKL,与破骨细胞前体细胞或成熟破骨细胞表面上的RANK结合后,促进破骨细胞的分化及骨吸收活性。成骨细胞及骨髓基质细胞分泌表达OPG可与RANKL竞争性结合,从而阻断RANKL与RANK之间的相互作用。体内多种激素或因子通过影响骨髓微环境内的OPG/RANKL比率来调节骨代谢。此外,乳腺上皮细胞表达有RANK,孕期在性激素的诱导下可表达RANKL,OPG/RANKL/RANK系统在孕期乳腺发育以及母体向胎儿的钙转运过程中发挥重要作用。阻断RANKL/RANK通路有望给骨质疏松、类风湿关节炎及癌症骨转移等骨破坏性疾病的治疗开辟新的途径。进一步研究应了解OPG/RANKL/RANK系统与其它信号传导途径的关系,重视骨骼、免疫及内分泌系统之间的相互作用。目前,开发与OPG功能相似或促进其表达的合成药物有可能成为具有良好经济效益和社会效益的产业。     

RANKL与骨重建

骨是一种动态更新的组织,它不断进行骨吸收（bone resorption）与骨形成（bone formation）的平衡,这个过程称之为骨重建（bone remodeling）．核因子κB受体活化因子配体（receptor activator of nuclear factor κB ligand,RANKL）是骨吸收和骨形成耦联的关键,具有诱导破骨细胞（osteoclast, OC）生成、活化,抑制破骨细胞凋亡的作用．RANKL最初发现于活化的T细胞,但骨重建过程中RANKL主要来源于骨细胞、成骨细胞和骨髓基质细胞．RANKL/核因子κB受体活化因子（receptor activator of nuclear factor κB,RANK）/骨保护素（osteoprotegerin, OPG）信号通路在成骨细胞调控破骨细胞生成的过程中起着重要的调节作用,是维持骨重建平衡的关键．本文就RANKL及其在骨中的分子作用机制作一综述.     

Nucleostemin在大鼠骨髓基质干细胞向成骨细胞诱导分化中的研究

目的探讨Nucleostemin（NS）在大鼠骨髓基质干细胞向成骨细胞诱导分化中的机制及作用。方法取4～6周龄雄性SD大鼠两侧股骨、胫骨骨髓基质细胞,原代及传代培养。取第3代骨髓间充质干细胞分别用普通和矿化培养基培养,通过相差倒置显微镜观察细胞生长、MTT法检测细胞增殖、碱性磷酸酶和茜素红钙染色了解成骨活性。免疫组化SABC法及免疫荧光法检测NS在细胞中的表达情况,比较NS分别在普通培养基和成骨细胞诱导培养基作用下的表达情况。结果大鼠骨髓间充质干细胞在矿化培养基诱导下其NS的表达较普通培养基培养下的表达明显减弱,且呈时间依赖性衰减。成骨细胞的NS表达则为阴性。在矿化液作用下,骨髓间充质干细胞可诱导为成骨细胞。MTT显示矿化液培养细胞生长潜伏期长,对数生长期较对照组延长。结论NS作为核干细胞因子,在干细胞中和某些肿瘤细胞中表达丰富。细胞分化后,其表达明显减少。因此,NS很可能作为大鼠基质干细胞是否具有潜在分化能力的标志性因子。     

RANKL在成釉细胞瘤骨吸收机制中的作用

目的:检测RANKL在成釉细胞瘤(ameloblastoma,AM)组织中的表达情况及探讨RANKL在AM骨吸收机制中的作用.方法:通过免疫组化方法检测RANKL在AM组织中的表达情况;通过建立AM细胞/新生大鼠骨细胞共培养体系,观察AM细胞诱导破骨细胞形成的活性,再以OPG(RANKL的抑制剂)进行干预,观察OPG对AM细胞诱导破骨细胞形成活性的影响.结果:RANKL在AM组织中有恒定的表达;AM细胞能够诱导新生大鼠骨细胞分化为成熟的破骨细胞,但此活性可被OPG明显抑制.结论:AM细胞诱导破骨细胞形成可能是AM骨吸收过程中局部破骨细胞形成的重要来源和机制,而RANKL在此过程中发挥重要作用.     

肿瘤坏死因子受体和配体超家族的新成员

骨原蛋白(OPG)／核因子κB受体激活剂的配体(RANKL)／核因子κB的受体激活剂(RANK)是肿瘤坏死因子受体和配体超家族成员。RANKL由成骨细胞前体／骨髓基质细胞和激活的T淋巴细胞合成,通过结合破骨细胞或树突状细胞表面的RANK受体,促进破骨细胞的形成、融合、激活和存活,并有助于树突状细胞对抗原的提呈作用,OPG作为RANKL的假受体,对此过程具有抑制作用。此外,OPG／RANKL／RANK系统在调节淋巴系统发育、哺乳期动物乳腺腺泡的形成以及大动脉钙化中也起着重要的作用,是一组多功能的细胞因子系统。     

机械应力影响鼠骨髓基质细胞骨保护素/NF-κB受体活化剂配体mRNA表达变化

骨保护素/NF-κB受体活化剂配体/NF-κB受体活化剂(OPG/RANKL/RANK)系统对破骨细胞生成、功能起着关键的作用,它的发现是骨生理代谢研究领域的重大进展。为研究生理性机械应力对鼠骨髓基质细胞OPG/RANKLmRNA表达变化的影响,进一步探讨机械应力对破骨细胞的影响机制,通过对鼠骨髓基质细胞施加不同时段的生理性的机械应力,并以RT-PCR半定量的方法检测OPG/RANKLmRNA表达变化趋势。结果显示随着加力时间的延长(6h后)RANKLmRNA表达减少34.4%,而OPGmRNA(9h后)表达增加73%,提示生理性应力能显著影响鼠骨髓基质细胞OPG/RANKLmRNA表达变化,从而在一定程度上阐明了生理性应力延缓骨质吸收的内在机制。     

体外定向诱导大鼠骨髓基质干细胞向成骨细胞分化的实验研究

目的研究大鼠骨髓基质干细胞的生长特点和诱导条件下的成骨能力。方法通过密度梯度离心和贴壁培养法分离成年大鼠骨髓基质干细胞,应用含地塞米松、p甘油磷酸纳和维生素c的诱导分化培养液定向诱导传代细胞向成骨细胞分化并检测碱性磷酸酶活性和细胞矿化作用。结果原代培养基质干细胞首先形成细胞集落,14d时集落间接近融合;传代细胞体积变大,约5～7d传代一次。诱导条件下,细胞碱性磷酸酶活性明显增高,并出现了矿化结节。结论骨髓基质干细胞易于分离培养及体外扩增,成骨能力肯定,可作为骨组织工程的种子细胞。     

小鼠破骨细胞诱导及成纤维生长因子受体表达检测

目的:检测成纤维生长因子受体(fibroblast growth factor receptors,FGFRs)在小鼠破骨细胞中的表达情况,为探讨FGFRs时破骨细胞的直接调控作用奠定基础.方法:采用巨噬细胞集落刺激因子(macrophage colony stimulating factor,M-CSF)和破骨细胞分化因子(receptor activator of nuclear factor-B ligand,RANKL)诱导小鼠骨髓单核细胞分化为破骨细胞.提取细胞总RNA后经逆转录获得小鼠破骨细胞cDNA,根据FGFRs基因编码区序列设计的引物进行PCR扩增并对PCR扩增产物进行测序.为进一步验证转录水平的结果,提取细胞总蛋白电泳后进行免疫印迹实验.结果:诱导5d后可见TRAP( )多核细胞出现,小鼠破骨细胞在转录水平和翻译水平均只可检测到FGFR1和FGFR3基因的表达产物.结论:M=CSF和RANKL可成功诱导出小鼠破骨细胞,FGFR1和FGFR3基因在小鼠破骨细胞中均有表达.     

重组可溶性核因子κB受体活化因子体外抑制甲状旁腺激素诱导的破骨细胞生成

新近发现的核因子κB受体活化因子配基（receptor activator of nuclear factor-κB ligand,RANKL）,核因子κB受体活化因子（receptor activator ofnuclear factor-κB,RANK）／护骨素（osteoprotegerin,OPG）细胞因子系统提高了对破骨细胞生物学和骨稳态分子水平的认识。RANKL与RANK之间的相互作用决定了破骨细胞的分化。本研究通过体外实验评价可溶性RANK （soluble RANK,sRANK）是否可作为RANKL的拈抗剂下调破骨细胞生成和骨吸收陷窝的形成。构建sRANK的原核表达载体,转化入大肠杆菌表达菌株Origami B（DE3）,成功表达了重组蛋白,亲和层析进行纯化。重组sRANK以剂量依赖方式抑制由甲状旁腺激素（parathyroid hormone,PTH）诱导的破骨细胞生成和骨吸收陷窝形成。RT-PCR实验证实,sRANK可显著抑制PTH刺激的小鼠骨髓细胞碳酸苷酶Ⅱ和抗酒石酸酸性磷酸酶mRNA的表达。结果表明,sRANK具有抗骨吸收功能,可能成为一种治疗以骨吸收加强为特征的骨疾病的新方法。     

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.