人类离体心房肌细胞的电生理研究

运用微电极技术研究人类离体心房肌,不仅为了解人类心肌的电生理学特性提供直接资料,还可用它来探讨患病心房肌纤维的电生理学特征、心律失常的发生机制以及研究药物、电解质及神经递质对人体心房肌的作用。随着心脏直视手术的广泛开展,人类离体心房肌细胞的电生理学研究也日益频繁。     

人类离体心房肌细胞的电生理研究

运用微电极技术研究人类离体心房肌,不仅为了解人类心肌的电生理学特性提供直接资料,还可用它来探讨患病心房肌纤维的电生理学特征、心律失常的发生机制以及研究药物、电解质及神经递质对人体心房肌的作用.随着心脏直视手术的广泛开展,人类离体心房肌细胞的电生理学研究也日益频繁.     

脂布福吉宁、哇巴因对豚鼠心室肌细胞外K~＋活度及跨膜动作电位的影响

用离子敏感微电极和常规微电极研究脂布福吉宁（Ｒｅｓ）和哇巴因（Ｏｕａ）对豚鼠心室肌细胞外Ｋ＾＋活度和动作电位（ＴＡＰ）的影响。结果表明：Ｒｅｓ可降低静息电位,动作电位振幅、间期,最大上升速率,使ａ＾ｏＫ升高;并诱发延迟性后去极化（ＤＡＤ）;Ｒｅｓ的作用与Ｏｕａ相似;电剌激使Ｋ＾＋在细胞间积累,积累量与频率相关。     

细胞外Ca^2＋内流入胞质的机制

细胞外Ｃａ＾２＋主要是通过塌压依赖性Ｃａ＾２＋通道和钙池耗竭依赖性Ｃａ＾２＋通道而内流的。前者主要见于电兴奋细胞,这一过程比较清楚;后者主要见非兴奋细胞,情况远较复杂：外来信号激活内贮钙池,钙池在释放Ｃａ＾２＋同时通过目前尚不清楚的途径将直接或间接传至质膜Ｃａ＾２＋通道,而诱发Ｃａ＾２＋内流。     

内皮素对培养心肌细胞内游离钙浓度的作用

实验用培养新生ＳＤ大鼠心室肌细胞,以Ｆｕｒａ－２／ＡＭ荧光指示剂负载检测收肌细胞内游离钙浓度（「Ｃａ＾２＋」）的变化,探讨内皮素－１（ＥＴ－１）对「Ｃａ＾２＋」ｉ的作用及其机制。结果显示：ＥＴ－１引起心肌细胞「Ｃａ＾２＋」ｉ升高有两个时相,瞬时相持续相。ＥＴ－１诱导的瞬时相「Ｃａ＾２＋」ｉ升高呈浓度依赖性,预先用ＥＴＡ特异性受阻断剂ＢＱ１２３处理,可阻断ＥＴ－１引起的「Ｃａ＾２＋」ｉ升高,揭示上述     

GM—CSF和IL—3对脐带血CD34＋细胞植入骨髓基质的促进作用

利用抗ＣＤ３４单克隆抗体吸附磁性微球的方法分离纯化脐带血ＣＤ３４＾＋细胞,将其种入照射后的成年骨髓基质。比较ｒｈＧＭ－ＣＳＦ、ＩＬ－３及两者的联合对植入效率的促进作用。结果表明：经２ｈ铺展贴壁后,对照组只有３６％的ＣＤ３４＾＋细胞植入基质,而生长因子预处理组则有６８－８９．６％的ＣＤ３４＾＋细胞植入基质。在长期液体培养体系中则显示了植入ＣＤ３４＾＋细胞多的处理组造血重建快速而持久。表明ＧＭ－ＣＳＦ     

兔膈肌力学模式对慢性电刺激的适应性改变和细胞外Ca …

目的：研究兔膈肌肌条力学对不同频率慢性电刺激（ＣＥＳ）的适应性变化特征和细胞外Ｃａ＾２＋变化夺其力学特征的影响。方法：测定正常对照组和ＣＥＳ组的颤搐收缩张力（Ｐｔ）、峰值张力时间（ＴＰＴ）、１／２松弛时间（１／２ＲＴ）、强直颤搐收缩张力（Ｐｏ）、疲劳指数（ＦＩ）和疲劳恢复指数（ＦＲＩ）;观察在无Ｃａ＾２＋Ｈａｎｋ’ｓ液和标准Ｈａｎｋ’ｓ液时肌条收缩张力消失和恢复的时间差异。结果：①同对照组作比较,     

心脏K^＋通道

Ｋ＾＋通道是生物膜上一种调节Ｋ＾＋流的跨膜蛋白质,广泛存在于各种可兴奋的细胞。在维持心脏正常功能方面发挥重要作用。本主要讨论内向整流Ｋ＾＋通道,延迟整流Ｋ＾＋通道,瞬进外向电流Ｋ＾＋通道,毒蕈碱／腺激活Ｋ＾＋通道,ＡＴＰ敏感性Ｋ＾＋通道的基本特性,及其在心脏电生理作用中的重功能,和相关的分子生物学信息。     

钙的光释入技术及其在细胞研究中的应用

Ｃａ＾２＋的光释放技术通过光解作用使预先引入细胞内的光敏感性螯合剂对Ｃａ＾２＋的亲和性改造从而实现细胞内游离钙离子浓度的调控,有助于阐明Ｃａ＾２＋作为第二信使对电兴奋性、肌肉收缩等细胞功能的调制作用。     

热应激心肌细胞损伤的线粒体机制探讨

目的：观察热应激对大鼠凡肌细胞线粒体氧化磷酸化和钙代谢功能的影响、研究线粒体膜渗透性转移（ＰＴ）的变化及其病理学意义、探索热应激心肌细胞损伤发生机制。方法：用Ｋｌａｒｋ氧电极极谱法测定线粒体呼吸功能,用生物发光法主肌ＡＴＰ含量及线粒体Ｃａ＾２＋。ＡＴＰ酶活性;用电感耦合等离子－原子发射光谱仪测定线粒体内Ｃａ＾２＋含量,用分光光度法测定线粒体膜ＰＴ。结果：热应激大鼠心肌细胞线粒体的呼吸控制率（ＲＣＰ     

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.