家兔发热时脑脊液和血浆中精氨酸加压素含量的变化及禁水的抗热作用

本实验观察了发热家兔脑脊液(CSF)和血浆中精氨酸加压素(AVP)含量的变化及禁水对家兔内毒素(ET)发热效应的影响。实验结果表明:1.隔区注射AVP可明显抑制家兔ET性发热效应;2.发热组家兔CSF和血浆中AVP含量较正常组明显降低;3.禁水可明显对抗家兔ET性发热效应,其抗热作用与CSF和血浆中AVP含量升高有关;4.禁水也可使正常家兔体温水平下移。上述实验结果提示,AVP可能是家兔体内一种内源性退热物质,同时在正常体温调节中也可能发挥一定的作用。     

嗜酸乳杆菌与嗜热链球菌共发酵互生机理的研究

目的:对嗜酸乳杆菌和嗜热链球菌共发酵时两者的互生作用机理进行研究。方法:以质量浓度100gL脱脂乳为培养基,将嗜酸乳杆菌主要代谢产物—氨基酸,如赖氨酸、精氨酸、缬氨酸分别以0.0083mgml、0.0036mgml、0.0053mgml的量加入含嗜热链球菌脱脂乳培养基中,40℃培养,测定凝乳时间;将嗜热链球菌的代谢产物-乳酸、甲酸分别为0.1332mgml和0.075mgml的量加入含嗜酸乳杆菌脱脂乳培养基中,37℃培养,测定其发酵乳的凝乳时间。结果:嗜热链球菌发酵乳凝乳时间由12h缩短到4h,pH为4.52～4.62,吉尔涅尔度为54.23～64.74°T;嗜酸乳杆菌发酵乳的凝乳时间由16h缩短为5h,pH为4.61～4.65;且嗜酸乳杆菌在CO2环境中发酵时,发酵时间明显缩短。结论:嗜酸乳杆菌和嗜热链球菌共发酵时具有互生关系。     

家兔迟发性面瘫模型建立及药物干预研究

目的:优化迟发性面瘫的建模方法,并对药物的神经保护作用进行观察。方法:家兔48只共96侧面神经,分A、B、C、D 4个实验组,以一侧面神经进行实验处理,另一侧为自身对照。A组:直视下钳夹损伤桥池段面神经;B组:直视下向桥小脑角注射动脉血,以诱导血管痉挛;C组:处理因素=A组+B组;D组:在C组基础上,应用药物(强的松+丹参+维生素B1+维生素B12)干预。观察家兔面瘫,并做面神经病理切片,比较各组间迟发性面瘫发生率、面瘫持续时间及预后。结果:面瘫发生情况:A组6只家兔(6/11,54.5%)出现迟发性面瘫;平均面瘫持续时间为13.2天。B组有2只(2/12,16.7%)出现迟发性面瘫,平均持续8天。C组6只(6/12,50%)家兔出现迟发性面瘫,平均持续14.3天。D组4只(4/12,33.33%)出现迟发性面瘫,平均持续6天。所有自身对照侧均无面瘫发生。病理:各组均见神经纤维水肿;A、C两组呈高度水肿改变,神经束周围结构紊乱;B组见神经内血管细小,而水肿较A、C两组轻微;D组呈轻度水肿改变。结论:C组出现迟发性面瘫几率高,是较好的模型;联合应用强的松、丹参、维生素B1、维生素B12虽不能防止迟发性面瘫发生,但可使迟发性面瘫病程明显缩短。     

电针降温作用及其与脑脊液中cAMP和PGE1含量变化的关系

cAM P和前列腺素E(PGE)是发热的重要中枢生物活性物质。我们实验室在最近的工作中发现,间断电针对家兔发热效应的抑制作用与其阻止脑脊液中cAMP和PGE_1含量升高有关。但这种实验是在给动物注射致热原后未出现发热效应时,给以多次电针刺激引起的     

错位双链寡核苷酸中碱基比例的测定研究

使用碱和碱性磷酸酶降解错位双链寡核苷酸 (Poly :Ⅰ :C12 U) ,使其生成三种核苷 ,再使用反相 高效液相色谱 (RP HPLC)方法 ,分析核苷的组成 ,从而计算出PolyⅠC12 U中的碱基组成比例 ,结果表明样品中的碱基比例接近设计比例 1 2∶1。     

磷脂酶C抑制剂U73122对COPD大鼠肺组织内MMP-9,MMP-12表达影响的实验研究

目的:探讨磷脂酶C抑制剂U73122对COPD大鼠肺组织内MMP-9,MMP-12表达的影响.方法:通过烟熏及气管内注入脂多糖(LPS)建立COPD大鼠模型,从第1d起通过尾静脉注射磷脂酶C(PLC)抑制剂U73122(以U73343为阴性对照),持续28天.第28d,观察各组大鼠肺组织病理变化,western blot法检测肺组织中MMP-9、MMP-12表达水平.结果:模型组和干预组大鼠MMP-9、MMP-12蛋白表达高于对照组(P＜0.05),干预组低于模型组(P＜0.05).干预组肺组织形态学改变较模型组改善(P＜0.05).结论:U73122通过抑制磷脂酶C(PLC)信号途径减少了COPD中MMP9、MMP12的表达,减轻肺组织结构破坏.     

杏仁内侧核注射AVP和AVPMcAb对家兔ET性发热效应的影响

目的和方法：在大脑杏仁内侧核微量注射精氨酸加压素（ＡＶＰ）和精氨酸加压素单克隆抗体（ＡＶＰＭｃＡｂ）,观察其对家兔内毒素（ＥＴ）性发热效应以及视前区一下丘脑前部（ＰＯＡＨ）温敏神经元放电活动的影响。结果：①杏仁内侧核微量注射ＡＶＰ能明显抑制家兔ＥＴ性发热效应,注射ＡＶＰＭｃＡｂ能明显易化家兔ＥＴ性发热效应;②杏仁外侧核分别注射ＡＶＰ和ＡＶＰＭｃＡｂ则对家兔ＥＴ性发热效应无明显影响;③杏仁内侧核分别注射ＡＶＰ和ＡＶＰＭｃＡｂ后ＰＯＡＨ热敏神经元和冷敏神经元放电活动均无明显变化。结论：家兔杏仁内侧核也是ＡＶＰ抗热效应的一个重要的作用部位,杏仁内侧核注射ＡＶＰ的抗热作用途径与隔区注射ＡＶＰ的抗热途径可能不同     

乌司他丁对大鼠毛细血管渗漏综合征肺毛细血管通透性的影响

目的:观察乌司他丁(UTI)注射液对毛细血管渗漏综合征(CLS)大鼠肺毛细血管通透性及肺血管内皮生长因子(VEGF)表达的影响,探讨UTI降低CLS大鼠肺毛细血管通透性的机制。方法:雄性SD大鼠120只,随机均分为三组。其中正常对照组(C组)20只,UTI干预组(U组)40只,模型组(M组)60只。实验动物观察12小时,处死前取静脉血ELISA法测血清VEGF;处死动物后取肺组织分别行病理学检查、干湿比重法测肺含水量、伊文思兰法测肺毛细血管通透性。结果:M组血清VEGF明显高于C组和U组(P<0.05),M组肺组织损伤较重,肺含水量及组织通透性均高于C组和U组(P<0.05)。结论:UTI可降低大鼠CLS肺毛细血管通透性,其作用机制可能是通过降低血中的VEGF表达。     

丙泊酚联合乌司他丁对内毒素所致大鼠急性肺损伤的保护作用

目的:评价丙泊酚联合乌司他丁对内毒素所致兔急性肺损伤的保护作用及其机制。方法:雄性SD大鼠60只,体重250～300 g,随机分为5组(n=12):空白对照组(C组)、丙泊酚组(P组)、乌司他丁组(U组)、丙泊酚+乌司他丁组(P+U组)和模型对照组(L组)。除C组外,其他组均静脉微量注射泵给予内毒素(LPS)8 mg/kg,P、U、P+U组在给予LPS后静注乌司他丁5×104U/kg或连续经静脉泵入丙泊酚8mg/(kg.h)。4h后测定血清肿瘤坏死因子α(TNF-α)及白介素10(IL-10)水平,取肺组织观察大体形态和光镜下计算肺泡损伤比值(IQA),测定肺组织湿/干重量比值(W/D)、脂质过氧化产物丙二醛(MDA)及超氧化物歧化酶(SOD)活性。结果:光镜下与C组比较,L组肺部损伤严重肺泡损伤比值(IQA)显著增加(P<0.05),与L组比较,P、U、P+U组肺部损伤严重肺泡损伤比值(IQA)明显减轻(P<0.05)。与L组比较,P、U、P+U组组织SOD活性明显增强(P<0.05)、W/D、MDA以及血清TNF-α及IL-10水平明显降低(P<0.05);P+U组较P、U组的上述指标改变更加显著(P<0.05)。结论:丙泊酚和乌司他丁对内毒素所致急性肺损伤均有保护作用,两者联合使用则保护作用效果更佳。     

磁处理水对家兔血脂影响的实验研究

目的:探讨饮用磁处理水时间的长短与降低家兔血脂的关系。方法:72只家兔平均分四组A组基础饲料组,饮自来水;B、C、D高脂饲料组,B组对照组饮自来水;C组治疗1组,30天后饮磁处理水,治疗30天后采耳血,分别测血清TC、TG、HDL-c、LDL-c水平。D组治疗2组,30天后饮磁处理水,治疗100天后采耳血,分别测血清TC、TG、HDL-c、LDL-c水平。结果:B组家兔血清TC、TG、HDL-c、LDL-c水平显著高于A组,(P<0.01);C组家兔TC、LDL-c水平显著低与B组(P<0.01);,但也显著高于A组(P<0.01);TG、HDL-c水平与B组相比无显著差异(P>0.05)。D组家兔血清TC、TG、LDL-c水平与B组相比均有明显下降(P<0.01),与A组比较差异无显著性(P>0.05),而HDL-c水平与A组比较明显上升(P<0.01)。结论:长期饮用磁处理水可以显著降低家兔血清高胆固醇含量,并恢复到正常状态。     

白萝卜提取物诱生干扰素的有效成份

本实验用CF-11纤维素柱层析,从白萝卜提取物中分离纯化到一种双链RNA,简称E.R.s.r-dsRNA(全称见正文)。实验证明,E.R.s.r-dsRNA在家兔体内可诱生高水平的干扰素;纳克(ng)水平即可在体外细胞培养中抑制病毒感染。E.R.s.r-dsRNA分子量略小于1.34×10~6道尔顿,它对RNase的耐受性比Poly Ⅰ:PolyC强。推测E.R.s.r-dsRNA可能有较好的应用前景。     

Interferon induction by mismatched analogues of polyinosinic acid . polycytidylic acid [(Ix,U)n.(C)n].

Interruption of the (I)n strand of (I)n.(C)n by unpaired bases [(U)] yielded mismatched analogues, (Ix,U)n.(C)n which were still effective as inducers of interferon, provided the I:U ratio (x) was equal or greater than 10. In highly sensitive interferon-induction systems such as primary rabbit kidney cells and human skin fibroblasts superinduced with cycloheximide and actinomycin D, (I10,U)n.(C)n and (I50,U)n.(C)n proved nearly as active as (I)n.(C)n. By virtue of their increased susceptibility to degradation by nucleases, (Ix,U)n.(C)n complexes with 10 less than or equal to x less than or equal to 50 may be expected not to persist as long in biological fluids as (I)n.(C)n, hence to induce fewer side effects.     

Heavy metals and spermatozoan motility. II. Turbidity changes induced by divalent cations and adenosinetriphosphate in sea urchin sperm flagella

The initial binding of synthetic polyribonucleotides and different RNAs to Ehrlich ascites cells has been studied using cell electrophoresis. When cells were pre-incubated in the presence of polylysine significant differences in the binding of different polyribonucleotides were observed. For example, Poly (A):Poly (U) caused a greater change in electrophoretic mobility than Poly (I):Poly (C). The increased electrophoretically detectable change after treatment with Ehrlich ascites RNA compared with E. coli tRNA could be correlated with increased uptakes of labelled Ehrlich ascites RNA compared with tRNA. An interesting observation was that when Poly (A) was added before Poly (U), a greater effect on electrophoretic mobility was found compared with the effects when the order of addition was reversed. It is suggested that copolymer formation from the homopolymers can occur at the cell surface.     

Dependence of 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen photoaddition on the conformation of ribonucleic acid

The photoaddition of 4'-(hydroxymethyl)-4,5',8-trimethylpsoralen (HMT) to different conformational states of RNA was studied. Poly(U), poly(A,U) (random copolymer), poly(A-U) (alternating copolymer), poly(A) . poly(U) (double stranded), and poly(U) . poly(A) . poly(U) (triple stranded) were reacted with HMT at different temperatures and salt concentrations. The conformation of the polymers was monitored by UV absorption and circular dichroism. It was found that the rate of HMT photoaddition changed dramatically at structural transitions in the RNA. The alternating copolymer poly(A-U) was found to have the highest rate of addition. Low salt and temperature produced maximal incorporation.     

Induction of interferon by polyribonucleotides containing thiopyrimidines.

The influence of thioketo substitution in pyrimidine bases of double-stranded polynucleotides on interferon induction was investigated. The stabilizing effect of 2-thioketo substitution was reflected in the increased interferon inducing activity of poly(A-s2U) over that of poly(A-U). Poly(A-s2U) and poly(I)-poly(s2C) were as effective as poly(I)-Poly(C) in rabbit cells. Poly(I)-poly(C) and poly(I)-poly(s2C) were compared in several animal species. No differences in biological effects were observed in rabbits and dogs. In rodents, poly(I)-poly(s2C) was less effective and less toxic.Poly(I)-poly(s2C) was highly resistant against degradation by human serum. Further investigations seem to be justified to elucidate whether this property offers any advantages for the potential clinical utilization of poly(I)-poly(s2C).     

Independence of length and temperature effects on the rate of helix formation between complementary ribopolymers

The rate of double helix formation by single stranded Poly A plus Poly U, Poly I plus Poly C, Poly G plus Poly C, and T2 DNA has been investigated as a function of both the length of the reacting strands and temperature. The length dependence of the rate is found to be independent of temperature. All of the reactions studied show a rate approximately proportional to the square root of the length of the shorter of the complementary strands. At or about 30°C below the melting temperature the ribopolymers react with about the same rate. This rate is four to five times slower than DNA renaturation rates. The effect of temperature on ribopolymer reaction rates is interpreted in terms of a steady-state model for helix propagation.     

Studies on polyribonucleotides. Synthesis of a polyinosinic: 6-thioinosinic acid copolymer

The enzymatic synthesis of a high molecular weight (s_20,w ～10) copolymer of inosinic and 6-thioinosinic acids [poly(I:s⁶I)] has been achieved. Poly (I:s⁶I) forms a double stranded complex with poly C which has a Tm significantly lower than a poly I · ply C complex of equivalent molecular weight.     

Base-Specific Endo-Exonucleolytic Activity of Chlamydomonas Nuclease C1&2

The reaction kinetics of nuclease C1&2 from Chlamydomonasreinhardtii were studied. It showed endo-exonucleolytic activitywith sugar non-specificity. The relative rates of RNA breakdownwere in order of poly(U) > poly(A) > yeast sRNA. In contrast,poly(G) and poly(C) released almost no acid-soluble materialsafter reacting with nuclease C1&2. The major products ofa 100% limit digest of synthetic RNA homopolymers were mononucleotideswith 3'-phosphate termini. Large oligonucleotides produced duringendo-exonucleolytic degradation also appeared carrying 3'-phosphatetermini. Nuclease C1&2 hydrolyzed single stranded DNA 20times faster than double stranded DNA by endo-exonucleolyticaction, releasing acid-soluble materials. High performance liquidchromatography of a 100% limit digest of salmon testes DNA demonstratedthat the major products were deoxymononucleotides with phosphateat 3'-position. Furthermore, the level of 3'-dCMP among themwas found to be extremely low. Poly(dC) and poly(me⁵dC) werehydrolyzed much more slowly than single stranded (or denatured)DNA, releasing acid-soluble materials. The present results suggestthat nuclease C1&2 is a base-specific nucleate 3'-oligonucleotidohydrolasedifferent from the restriction enzymes. (Received January 13, 1986; Accepted March 25, 1986)     

Molecular aspects on the specific interaction of cytotoxic plant alkaloid palmatine to poly(A)

The interaction of the protoberberine alkaloid palmatine with single and double stranded structures of poly(A) was studied by various biophysical techniques. Comparative binding studies were also performed with double stranded DNA, t-RNA, poly(C)·poly(G), poly(U) and poly(C). The results of competition dialysis, fluorescence, and absorption spectral studies converge to reveal the molecular aspects of the strong and specific binding of palmatine to single stranded poly(A). The binding affinity of palmatine to natural DNA, t-RNA and double stranded poly(A) was weaker while no binding was apparent with single stranded poly(U), poly(C) and double stranded poly(C)·poly(G). The strong affinity of the alkaloid to single stranded poly(A) in comparison to the double stranded structure was also revealed from circular dichroic and viscometric studies. The effect of [Na⁺] ion concentration on the binding process revealed the significant role of electrostatic forces in the complexation. The presence of bound alkaloid also remarkably affected denaturation–renaturation of stacked helical poly(A). The energetics of the strong binding to poly(A) was studied from thermodynamic estimation from van Hoff’ analysis of the temperature dependent binding constants and ultra sensitive isothermal titration calorimertry, both suggesting the binding to be exothermic and enthalpy driven. This study provides detailed insight into the binding specificity of the natural alkaloid to single stranded poly(A) over several other single and double stranded nucleic acid structures suggesting its potential as a lead compound for RNA based drug targeting.     

Combination of Poly I:C and arsenic trioxide triggers apoptosis synergistically via activation of TLR3 and mitochondrial pathways in hepatocellular carcinoma cells

Poly I:C (polyinosinic acid:polycytidylic acid), an analogue of dsRNA (double-stranded RNA), can lead to apoptosis in human cancer cells and has been used as an adjuvant to treat cancer patients. ATO (arsenic trioxide) is used effectively in the treatment of HCC (hepatocellular carcinoma). We sought to evaluate whether Poly I:C could enhance the potentiation of ATO in HCC. Combination of Poly I:C and ATO synergistically inhibited the growth of SMMC-7721 cells. Treatment with Poly I:C alone or combined with ATO-activated TLR3 (Toll-like receptor 3) pathway, increased ROS (reactive oxygen species) generation and mitochondrial dysfunction. The combined treatment also caused caspase-3, -8, -9 activation. Moreover, the combined therapy caused Bcl-2 and survivin down-regulation, Bax up-regulation and Bid activation. In conclusion, the Poly I:C and ATO combination is potentially a novel and effective approach for the treatment of HCC.