不同低氧运动模式对大鼠免疫功能的影响

目的:探讨不同低氧运动模式对大鼠免疫功能的影响。方法:30只SD大鼠随机分为常氧运动组(对照组)、高住高练组和高住低练组,对照组大鼠每天在常氧环境下生活23 h,训练1 h;高住高练组每天在低氧环境生活23 h,训练1 h;高住低练组每天在低氧环境生活12 h,常氧环境下生活11 h,训练1 h。全血分析仪分析全血指标,流式细胞仪检测CD4~ 和CD8~ 占有的百分比。结果:与高住低练组及对照组比较,高住高练组大鼠血液红细胞计数(RBC)和血红蛋白水平(Hb)升高,CD4~ T细胞百分数降低,CD8~ T细胞百分数升高,CD4~ /CD8~ 比值下降,差异均具有统计学意义(P<0.05)。对照组大鼠、高住高练组和高住低练组ELISPOT斑点数依次为(230.0±10.6)/2×10~5个脾细胞、(56.5±6.8)/2×10~5个脾细胞和(89.3±9.8)/2×10~5个脾细胞,差异有统计学意义(P<0.05)。结论:低氧运动可以提高机体氧运输能力,但是可能会损害机体免疫功能。     

自主神经系统参与低氧下的免疫调节作用

目的：探讨低氧条件下自主祖辈 经系统对大鼠脾淋巴细胞转化的调节作用。方法：检测减压低氧下外周血中神经递质与脾淋巴细胞转化。结果：大鼠5km低氧暴露24h,脾淋巴细胞对丝裂原反应性下降,外周交感神经损毁后则可阻断低氧对此的抑制作用;小鼠于真空瓶中0.07MPa缺氧10min血浆中去甲肾上腺素（NE）与肾上腺素（E）均明显升高;大鼠5km低氧24h,血浆中乙酰胆碱水平下降;体外培养的大鼠脾淋邓细胞中加入不同浓度的乙酰胆碱,胸腺嘧啶核苷掺入作用呈浓度依赖性增加。结论：以上结果提示自主神经系统参与低氧下的免疫调节,交感神经系统有免疫抑制作用,副交感神经起免疫增强作用。     

低氧暴露条件下高原鼠兔和大鼠HPA轴活动的比较

采用人工模拟低气压低氧的方法比较研究了不同程度（模拟海拔5 km和7 km)和不同时间（24d和5d）低氧暴露,对大鼠和高原鼠兔（Ochotona curzoniae）下丘脑-垂体-肾上腺皮质 (hypothalamo-pituitary-adrenalcortex,HPA)轴活动的影响。结果如下：7 km低氧暴露24 h,大鼠下丘脑的促肾上腺皮质激素释放激素（corticotropin-releasing actor,CRF）和肾上腺皮质激素皮质酮分泌显著增加,大鼠HPA低氧暴露对大鼠HPA 轴活动无显著差异。低氧暴露5天后,大鼠7 km、5 km组的HPA轴活动与对照相比无明显差异。低氧暴露对高原鼠兔的HPA轴无明显影响。上述结果表明：低氧暴露的时间和程度与大鼠HPA的活动密切相关;从HPA的活动来看,高原鼠兔表现出较强的低氧耐受性。     

低氧暴露对大鼠下丘脑CRF分泌的影响

目的和方法：利用人工模拟低氧及放射免疫测定（RIA）法,观察不同低氧（5km,7km）暴露对大鼠下丘脑分泌促肾上腺皮质激素释放激素（C orticotropin-releasing factor,CRF）的作用和血浆皮质酮水平的变化。比较低氧暴露不同时间（2h,24h,5d,15d）后,大鼠下丘脑CRF分泌和血浆皮质酮的变化。结果：低氧暴露2h,24h后下丘脑的CRF分泌明显增加,血浆皮质酮水平显著升高,这种变化随着低氧程度的加深而增强,随着低氧暴露时间的延长（5d）上述变化减弱。至慢性低氧暴露15d后,下丘脑CRF分泌及血浆皮质酮水平与对照组相比已无显著差异,基本恢复到对照水平。结论：动物暴露于低氧环境后,下丘脑CRF分泌及血浆皮质酮水平变化为：低氧暴露2h,24h后CRF分泌和皮质酮分泌被激活;低氧暴露5d后CRF分泌和皮质酮分泌活动减弱,并开始恢复;至低氧暴露15d后,这种分泌活动基本恢复,进入恢复期。     

新生大鼠下丘脑CRF和AVP神经元对急性低氧的应答

目的:观察肾上腺摘除新生大鼠下丘脑促肾上腺皮质激素释放激素(CRF)和精氨酸加压素(AVP)神经元对急性低氧的应答.方法:在低压氧舱中模拟高海拔低氧,用放免法测定AVP和CRP含量.结果:新生大鼠暴露于急性低氧环境下(模拟5 000 m和7 000 m海拔高度,24 h),其下丘脑CRP在3 d和7 d龄大鼠中无明显变化,但14d、21 d和28 d时低于对照;下丘脑AVP在3 d大鼠中亦无变化,但14 d时低于对照,7 d、21 d及28 d时高于对照.两者对低氧的应答模式随日龄而变化.摘除肾上腺后,14 d、21 d及28 d大鼠下丘脑CRF和AVP含量均显著低于同龄完整大鼠,此时暴露于急性低氧环境下,CRF和AVP无进一步的变化.结论:摘除肾上腺抑制下丘脑CRF和AVP的发育,影响它们对低氧应激的正常应答.     

成肌纤维细胞在大鼠低氧性肺动脉高压发病中的作用

目的探讨低氧性肺动脉高压(HPH)无肌性肺动脉肌化的细胞来源.方法雄性Wistar大鼠40只,分为对照组和低氧(3、7、14、21d组),每组8只,低氧组复制HPH大鼠模型.测定各组平均肺动脉压(mPAP),右心室肥大指数(RVHI),肺小动脉病理及其形态计量学;免疫组化测定各组肺微血管α-平滑肌肌动蛋白(α-SMA)表达;透射电镜观察微血管的超微结构改变.结果 (1)低氧7d起大鼠mPAP、管壁面积/管总面积(WA%)、管腔面积/管总面积(LA%)分别为(18.41±0.37)mmHg、(52.2±0.8)%、(47.8±0.8)%与对照组(14.02±0.41)mmHg、(64.5±1.3)%、(35.5±1.3)%比较差异有显著性(P<0.05),低氧14天起稳定于高水平;低氧14d RVHI为(25.0±1.8)%与对照组(23.6±0.5)%比较差异也有显著性(P<0.05).(2)从低氧7d开始无肌型动脉、部分肌型动脉、肌型动脉的构成比分别是39%、46%、15%与对照组60%、35%、5%比较差异有显著性(P＜0.005).(3)免疫组化发现,腺泡内肺动脉管壁α-SMA的表达随着低氧时间的延长,α-SMA表达量逐渐增多.(4)透射电镜观察21d组增厚的重塑血管壁,位于内外弹性膜之间的细胞为成肌纤维细胞表型,外层具有与它紧密联系的成纤维细胞.结论在低氧性肺动脉高压时,成纤维细胞转化为成肌纤维细胞是腺泡内肺动脉重塑的重要原因之一.     

急性低氧和腺苷对大鼠脾脏T淋巴细胞增殖的影响

目的:观察急性低氧和腺苷对大鼠脾脏T淋巴细胞增殖的影响,以探讨急进高原时机体免疫功能改变的规律和机制.方法:大鼠在5 000 m模拟高原减压低氧3 d后,用3H-TdR掺入法检测脾脏T淋巴细胞增殖功能,增加细胞培养液中腺苷浓度观察对T淋巴细胞增殖的影响.结果:在5.0 mg/L 和2.5 mg/L刀豆素A(concanavalin A,ConA)的刺激下,对照组大鼠脾脏T淋巴细胞的刺激指数分别为64.0±23.7和43.5±21.7;急性低氧组大鼠显著降低至29.4±11.3 和20.2±16.1;10 μmol/L和100 μmol/L腺苷能够显著抑制大鼠脾脏T淋巴细胞的增殖反应,且这种抑制作用具有明显的浓度依赖性.结论:急性低氧可在一定程度上抑制T淋巴细胞功能,这种抑制作用可能与低氧引起的腺苷含量增加有关.     

5-HD对慢性低氧肺动脉高压大鼠肺动脉平滑肌PKC-ɑ表达的作用

目的:研究线粒体ATP敏感钾通道(mitoKATP)抑制剂5-羟基癸酸盐(5-HD)对慢性低氧肺动脉高压大鼠的影响及其潜在机制。方法:雄性SD大鼠48只,随机分成4组(n=12):①正常对照组;②慢性低氧组;③慢性低氧+5-HD组;④慢性低氧+Diazoxide(mitoKATP开放剂)组;除正常对照组外,其余3组置于氧舱内(氧浓度10%±0.3%),每天低氧8 h,并接受不同的干预,共4周。干预结束后右心导管法测各大鼠肺动脉压,RT-PCR和Westernblot检测各组大鼠肺动脉PKC-ɑ蛋白和mRNA的表达。结果:①慢性低氧组肺动脉压显著高于正常组(P<0.01),同时慢性低氧+Diazoxide组与慢性低氧+5-HD组肺动脉压较慢性低氧组显著减低(P<0.01)。②慢性低氧组PKC-ɑ蛋白及mRNA的相对表达显著高于正常组(P<0.05)。结论:5-HD对慢性低氧肺动脉高压起保护作用,其机制可能是抑制线粒体ATP敏感钾通道。     

模拟高原游泳运动对大鼠血液粘滞度及心功能的影响

目的:研究低氧复合游泳运动对大鼠血液流变学及心脏功能的影响.方法:大鼠分为三组:常氧对照组、低氧组和低氧复合游泳运动组.低氧大鼠每天在模拟海拔4 000 m 低氧1.5 h后,升至5 000 m,持续减压23 h/d,共5周.低氧运动大鼠每天在4 000 m模拟海拔游泳运动1 h(6 d/w),然后升至5 000 m.多导生理记录仪测定心脏功能,E-型锥板粘滞度仪测定血液粘滞度,放射性生物微球法测定心输出量.结果:低氧时,大鼠血球压积明显升高,全血粘度显著增加.低氧复合运动未引起血球压积的进一步升高,血液粘滞度显著降低.低氧组大鼠左、右室心肌最大舒缩速度显著提高,低氧复合运动后最大舒缩速度进一步提高,心输出量显著增加.结论:在一定程度的低氧下,适当的体力活动可显著增强心脏功能,显著降低血液粘滞度.这种改变有利于改善低氧时机体各器官和组织的供氧状态,促进习服.     

生长激素和催乳素放射免疫测定法的建立与应用

目的：建立测定大鼠垂体和血浆中生长激素（GH）和催乳素（PRL）含量的高特异性、高灵敏度的双抗放射免疫测定（RIA）法;研究急性低氧对垂体激素GH和PRL的作用。方法：用氯胺－T法进行抗原放射性碘标记;采用平衡饱和加样程序的双抗RIA法测定。结果：用该方法测定急性低氧（0．5h）时血浆和垂体GH和PRL含量,7km低氧,垂体GH含量明显升高（P＜0．05）,血浆则相反;7km低氧,明显降低垂体和血浆PRL含量（P＜0．01）;而5km低氧对GH和PRL的作用与对照组比无统计学差异。结论：本双抗RIA法具有高特异性、高灵敏度及简便易行等特性;用该法测定提示急性低氧可抑制大鼠GH和PRL的分泌。     

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.     

A Unique Protease Cleavage Site Predicted in the Spike Protein of the Novel Pneumonia Coronavirus (2019-nCoV) Potentially Related to Viral Transmissibility

正Dear Editor,In December 2019, a novel human coronavirus caused an epidemic of severe pneumonia(Coronavirus Disease 2019,COVID-19) in Wuhan, Hubei, China(Wu et al. 2020; Zhu et al. 2020). So far, this virus has spread to all areas of China and even to other countries. The epidemic has caused 67,102 confirmed infections with 1526 fatal cases     

Curcuminoids as inhibitors of thioredoxin reductase: A receptor based pharmacophore study with distance mapping of the active site

Curcumin is the yellow pigment of turmeric that interacts irreversibly forming an adduct with thioredoxin reductase (TrxR), an enzyme responsible for redox control of cell and defence against oxidative stress. Docking at both the active sites of TrxR was performed to compare the potency of three naturally occurring curcuminoids, namely curcumin, demethoxy curcumin and bis-demethoxy curcumin. Results show that active sites of TrxR occur at the junction of E and F chains. Volume and area of both cavities is predicted. It has been concluded by distance mapping of the most active conformations that Se atom of catalytic residue SeCYS498, is at a distance of 3.56 from C13 of demethoxy curcumin at the E chain active site, whereas C13 carbon atom forms adduct with Se atom of SeCys 498. We report that at least one methoxy group in curcuminoids is necessary for interation with catalytic residues of thioredoxin. Pharmacophore of both active sites of the TrxR receptor for curcumin and demethoxy curcumin molecules has been drawn and proposed for design and synthesis of most probable potent antiproliferative synthetic drugs.     

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.