慢性低氧下普通大鼠与低氧敏感大鼠的血液气体变化

普通大鼠（ＳＤ）与低氧敏感大鼠（ＨＳ）经减压舱内模拟海拔５０００ｍ高度下３周低氧,观察到ＳＤ与ＨＳ的Ｈｂ有显著差异,前者高于后者（分别为２７．３±０．６;２４．５±０．８ｇ％Ｐ＜０．０１）。此时ＳＤ血液中的ＰＣＯ２已恢复正常,而ＨＳ血液中的ＰＣＯ２却比ＳＤ血液中的ＰＣＯ２低（分别为４．３±０．１;５．６±０．３ｋＰａＰ＜０．０１）。在慢性低氧初期,ＨＳ的ｐＨ值比ＳＤ明显降低（分别为７．１８±０．０３;７．２９±０．０２,Ｐ＜０．０５）。但随着低氧时间延长ＨＳ的ｐＨ值很快上升并超过ＳＤ（分别为７．２５±０．０２;７．１７±０．０３Ｐ＜０．０５）。两者的血液氧没有明显差异。实验结果提示普通大鼠与低氧敏感大鼠对慢性低氧反应有不同的生理机制。     

急性低氧对大鼠脑组织钙调素含量及其依赖性蛋白激酶Ⅱ活性的影响

本实验观察了活性钙调素（ＣａＭ）含量和ＣａＭ依赖性蛋白激酶Ⅱ（ＣａＭｋｉｎａｓｅⅡ）活性在急性低氧（模拟海拔７０００ｍ,５ｈ）和常氧对照大鼠脑子组织中的变化。用流式产胞仪（ＦＡＣＳ）所测两组动物脑皮层细胞的ＣａＭ,平均荧光强度分别为４０．０±４．９和４６．１±５．８,急性低氧组明显低于常氧对照组（Ｐ＜０．０５）;用同位素液闪计数法所测两组动物皮层脑匀浆提取液中ＣａＭｋｉｎａｓｅⅡ活性,分别为１８４．３±８．１和１９８．８±９．４ｐｍｏｌＰｉ·ｍｉｎ－１·ｍｇ－１ｐｒｏ,急性低氧组明显低于常氧对照组（Ｐ＜０．０１）。结果提示ＣａＭ和ＣａＭｋｉｎａｓｅⅡ对低氧较为敏感,急性低氧时中枢神经细胞结构或功能的紊乱可能与活性ＣａＭ的含量减少和ＣａＭｋｉｎａｓｅⅡ活性能下降有关。     

丹皮酚对心肌细胞自律性和延迟后除极的影响

目的与方法：采用常规玻璃微电极技术研究丹皮酚对离体心肌细胞自律性（ＡＭ）、延迟后除极（ＤＡＤ） 及触发活动（ＴＡ）的影响。结果：１．８×１０－４ｍｏｌ／Ｌ丹皮酚灌流组,肾上腺素（Ａｄｒ）的阈浓度空白对照组为（１．２８±０．５７）μｍｏｌ／Ｌ,药后为（１．５６±０．５３）μｍｏｌ／Ｌ（ｎ＝９,Ｐ＞０．０５）;用（１．８×１０－ ３） ｍｏｌ／Ｌ丹皮酚（Ｐａｅ）灌流组,Ａｄｒ 浓度由空白对照组的（１．２２ ±０．６２）μｍｏｌ／Ｌ升高到（６．２２±２．１１）μｍｏｌ／Ｌ（ｎ＝９,Ｐ＜０．０１）。１．８×１０－３ｍｏｌ／Ｌ的Ｐａｅ 能明显抑制哇巴因（Ｏｕａ）诱发的ＤＡＤ的幅值,当基本刺激周长为５００,４００,３００ 和２００ ｍｓ 时,其ＤＡＤ幅值从（５．５±２．０）ｍＶ,（７．３±２．１）ｍＶ,（８．０ ±２．４）ｍＶ和（９．２±１．９）ｍＶ减小到（３．０±１．１）ｍＶ、（３．６±１．７）ｍＶ,（４．３±２．０） ｍＶ和（５．９ ±１．６） ｍＶ,Ｐ＜０．０１。当基本刺激周长为２００ ｍｓ时,ＴＡ 数目由５．５±１．０ 降至０．７±０．３（Ｐ＜０．０１）。结论：丹皮酚能抑制心肌细胞ＡＭ、ＤＡＤ及ＴＡ,具有抗心律失常作用     

低氧对横断脊髓大鼠脊髓反射兴奋性的影响

本文用低压舱模拟不同海拔高度,测定横断脊髓大鼠脊髓反射兴奋性恢复曲线。断脊髓组和对照组自海拔２０００ｍ以后脊髓反射兴奋性逐渐增高,但两组出现差异有显著性的海拔高度不同,断脊髓组为海拔４０００ｍ,对照组为海拔３０００ｍ。对照组与断脊髓组在同一海拔高度上比较,除海拔３０００ｍ时差别有显著性（Ｐ＜０．０５）外,在其它各海拔高度上两组间差异无显著性（Ｐ＞０．０５）。结果表明,低氧时脊髓以上中枢和脊髓都参与脊髓反射兴奋性升高的调节     

第二信使介导模拟低氧下丘脑CRF分泌

用模拟高原低氧的方法研究急性低氧条件下促肾上腺皮质激素释放因子（ｃｏｒｔｉｃｏｔｒｏｐｉｎ－ｒｅｌｅａｓｉｎｇｆａｃｔｏｒ,ＣＲＦ）分泌的变化及第二信使参与ＣＲＦ分泌的作用。低氧（海拔７ｋｍ）１ｈ后,正中隆起（ｍｅｄｉａｎｅｍｉｎｅｎｃｅ,ＭＥ）处ＣＲＦ含量明显下降（Ｐ＜０．０５）,下丘脑（ｈｙｐｏｔｈａｌａｍｕｓ,Ｈｙ）ＣＲＦ（不含ＭＥ）含量无明显变化,而Ｈｙ内ｃＡＭＰ含量明显增加（Ｐ＜０．０１）。脑室注射Ｆｏｒｓｋｌｉｎ、ＴＰＡ后低氧暴露（海拔５ｋｍ）１ｈ,ＭＥＣＲＦ含量下降（Ｐ＜０．０５;Ｐ＜０．０５）,ＨｙＣＲＦ无明显变化。脑室注射Ｆｏｒｓｋｌｉｎ后ＨｙｃＡＭＰ含量升高（Ｐ＜０．０５）。脑室注射Ｈ７和ＰＫＡ抑制剂,ＭＥＣＲＦ升高（Ｐ＜０．０５;Ｐ＜０．０１）,ＨｙＣＲＦ和ＨｙｃＡＭＰ均无显著变化。上述结果表明急性低氧应激中ＣＲＦ分泌显著增加,第二信使通路ＰＫＡ和ＰＫＣ通路均参与ＣＲＦ分泌     

α受体激动对绵羊心肌瞬时性内向离子流的影响

用乙酰毒毛旋花子甙元（ＡＳ）０．０５μｍｏｌ／Ｌ诱发绵羊心浦肯野纤维产生稳定的瞬时性内向离子流（Ｉｔｉ）,用普萘洛尔０．５μｍｏｌ／Ｌ阻断β受体,观察α受体激动剂苯肾上腺素（ＰＥ）０．３,１．０μｍｏｌ／Ｌ对Ｉｔｉ幅值与时程的影响。ＰＥ１．０μｍｏｌ／Ｌ灌流２０,５０ｍｉｎ时Ｉｔｉ幅值分别由对照值１２．８±１．９ｎＡ减小至１０．７±１．２ｎＡ（ｎ＝５,Ｐ＜０．０５）与９．６±１．９ｎＡ（ｎ＝５,Ｐ＜０．０１）;ＩｔｉＤ５０时程分别由对照值１４５±２４．４ｍｓ延长至１８３．３±２８．１ｍｓ（ｎ＝５,Ｐ＜０．０５）与２０７．５±３４．２ｍｓ（ｎ＝５,Ｐ＜０．０１）,ＰＥ对Ｉｔｉ的抑制作用呈剂量依赖性与时间依赖性。Ｉｔｉ到达峰值的时间和回复到基线的时间都延长,提示ＰＥ作用下Ｉｔｉ通道动力学发生了变化。如果在β受体激动剂异丙肾上腺素（ＩＳＯ）１．０μｍｏｌ／Ｌ增强Ｉｔｉ的基础上,ＰＥ１．０μｍｏｌ／Ｌ灌流１０ｍｉｎ,对Ｉｔｉ幅值的抑制及时程的延长作用更显著,Ｉｔｉ幅值由对照值１５．６±３．２ｎＡ减小到１０．３±２．２ｎＡ;ＩｔｉＤ５０由９２．５±１４．３ｍｓ延长到１３２．５±３６．０ｍｓ（ｎ＝５,Ｐ＜０．０１）。     

间歇性低氧对大鼠心室肌细胞短暂外向电流的影响

利用全细胞膜片箝方法研究间歇性低氧后左、右心室肌细胞短暂外向电流（Ｉｔｏ）的变化,以探讨间歇性低氧增强心肌电稳定性的离子机制。大鼠间歇性暴露于低氧环境２８ｄ（Ｈ２８,６ｈ／ｄ）后,右心室肌细胞的Ｉｔｏ密度较常氧对照组明显增加（１６１８±４６１比６３２±１３５ｐＡ／ｐＦ,Ｐ＜００５）,而左心室肌细胞Ｉｔｏ密度与对照组无明显差异。间歇性低氧暴露４２ｄ（Ｈ４２）动物,其左、右心室肌细胞Ｉｔｏ密度与对照组无明显差异。Ｉｔｏ激活、失活和恢复动力学变化主要表现为Ｈ４２组左、右心室肌细胞的稳态失活曲线明显向负电压方向移位。左心室细胞的半数失活电压（－３８９±２３）ｍＶ与对照组（－３２８±５９）ｍＶ比较,具有显著性差异（Ｐ＜００１）;右心室细胞的半数失活电压（－４１９±４５）ｍＶ与对照组（－３３５±３５）ｍＶ比较,具有显著性差异（Ｐ＜０００１）。据此可推断,Ｉｔｏ密度的改变可反映心室在低氧早期阶段的不同动力学反应。失活动力学改变参与间歇性低氧心脏保护机制     

低氧对新生大鼠脾单个核细胞DNA合成及转化的影响

本研究以荧光法测定脾单个核细胞ＤＮＡ合成及ＭＴＴ比色法测定的脾单个核细胞对ＣｏｎＡ的增殖反应,观察模拟高原低氧对出生后１４天大鼠上述两指标的影响,同时也观察了交感神经和副交感神经的活动状态,以初步探讨低氧对上述两指标的作用是如何介导的。结果表明：５ｋｍ海拔高度低氧作用２４ｈ不抑制脾单个细胞ＤＮＡ合成及脾单个核细胞转化,而作用５天时则抑制ＤＮＡ合成及脾单个核细胞转化,分别为对照组的５６．６％（Ｐ＜０．０１）和８６．８％（Ｐ＜０．０５）;７ｋｍ海拔高度低氧作用２４ｈ,ＤＮＡ合成及脾单个核细胞转化均受抑制,分别为对照组的６１．０％（Ｐ＜０．０１）和８１．２％（Ｐ＜０．０１）;７ｋｍ海拔２４ｈ低氧导致脾脏中乙酰胆碱下降,儿茶酚胺升高;用ＤＳＰ－４中枢药理性损毁ＮＥ神经元,可使脾单个核细胞ＤＮＡ合成的抑制程度减弱,脾脏中儿茶酚胺含量下降。这些结果表明低氧可抑制新生大鼠脾单个核细胞的ＤＮＡ合成及转化,并可能与交感神经兴奋及副交感神经抑制有关     

α受体激动对绵羊心脏浦肯野纤维延迟后除极的影响

用乙酰毒毛旋花子成元０．２μｍｏｌ／Ｌ诱发绵羊心脏浦肯野纤维产生延迟后除极（ＤＡＤ）,采用细胞内微电极记录。在用普奈洛尔１．０μｍｏｌ／Ｌ阻断β受体条件下,苯肾上腺素１．０μｍｏｌ／Ｌ使ＤＡＤ幅值由８．１±２．２ｍＶ增至９．５±２．８ｍＶ,时程由２４０±４７ｍｓ延长到２７３±４７ｍｓ（ｎ＝１３,ＰＭ＜０．０１）,ＤＡＤ上升速率由０．０３９±０．０２３Ｖ／ｓ增至０．０５１±０．０２６Ｖ／ｓ（ｎ＝１３,Ｐ＜０．０５）,ＤＡＤ在动作电位后出现的时间提前了３０±４７ｍｓ（ｎ＝１３,Ｐ＜０．０５）。用去甲肾上腺素１．０μｍｏｌ／Ｌ增强ＤＡＤ引起触发活动时,酚妥０拉明１．８μｍｏｌ／Ｌ不能抑制触发活动,普奈洛尔１．０μｍｏｌ／Ｌ能抑制之。上述结果表明α受体激动对ＤＡＤ有轻度增强作用,但由ＤＡＤ引起的触发活动,α受体阻滞剂的抑制作用不如β受体阻滞剂有效。     

高原低氧性肺动脉高压的多普勒超声研究

应用脉冲式或连续式多普勒超声技术,对１８例海拔３２００ｍ高原正常人及２５例高原心脏病（ＨＡＨＤ）患者测定其肺动脉压。正常组及ＨＡＨＤ无瓣膜返流组１０例应用Ｈａｈａｍ回归方程,肺动脉平均压（ＰＡＭＰ）分别为２．８４±０．４及３．７３±０．５７ｋＰａ（ｋＰａ＝７．５ｍｍＨｇ）;ＨＡＨＤ有三尖瓣返流组８例用ＴＲＰＧ法测得ＰＡＳＰ为６．１３±１．７３ｋＰａ;ＨＡＨＤ有肺动脉瓣返流组Ｔ例用ＰＲＰＧ法测得ＰＡＤＰ为４．０±０．７３ｋＰａ。表明多普勒超声技术的不同方法可用于不同病理状态下高原低氧性肺动脉高压的测定,并可揭示出现瓣膜返流改变时高原低氧性肺动脉高压的程度。     

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.