机械牵张对缺血缺氧心肌细胞微管的影响

目的:探讨机械牵张对缺血缺氧心肌细胞微管的影响.方法:建立离体培养的SD乳鼠心肌细胞机械牵张模型,施加无糖缺氧刺激因素模拟烧伤早期缺血缺氧损害,实验分为10%牵张组(S组)、缺血缺氧组(I组)及10%牵张+缺血缺氧组(IS组),分别在刺激前和后1、3、6、12小时4个时相点进行观察,采用免疫荧光染色观察微管的变化,并用免疫蛋白印迹检测β-tubulin含量变化.结果:3小时后S组微管呈现增强趋势,I组微管有明显破坏,可见大量断裂微管分布于核周,IS组微管破坏严重,无聚合状态微管存在,细胞完整性受损.刺激后S组β-tubulin含量逐渐增多,I组则减少,IS组减少显著.12小时后IS组与其他2组差异显著(P＜0.01).结论:机械牵张加重了缺血缺氧对心肌细胞微管的破坏,可能是"休克心"发生发展的重要原因之一.     

山楂叶总黄酮对乳鼠心肌细胞缺血缺氧损伤的实验研究

目的 研究山楂叶总黄酮对缺血缺氧损伤后心肌细胞的影响。方法以3d龄SD乳鼠心室肌进行心肌细胞培养并建立缺血缺氧损伤模型。研究山楂叶总黄酮对缺血缺氧心肌细胞心率失常、停搏时间、细胞乳酸脱氢酶(LDH)的泄漏量、细胞丙二醛(MDA)、超氧化物歧化酶(SOD)和一氧化氮(NO)含量等生化指标的影响。结果山楂叶总黄酮能减轻缺血缺氧损伤后心肌细胞心率失常的程度，推迟心肌细胞的停搏时间，减少心肌细胞LDH的释放量，降低MDA含量并提高细胞内SOD酶的活力和NO的含量。结论山楂叶总黄酮对缺血缺氧损伤的心肌细胞具有明显的保护作用。     

阿片受体激活对培养心肌细胞缺氧／复氧损伤的保护作用

目的：观察δ阿片受体激活剂D-丙（2）-D-亮（5）脑啡肽（DADLE）对培养心肌细胞缺氧／复氧（H／R）损伤的保护作用。方法：采用培养的SD大鼠乳鼠的心肌细胞，建立H／R损伤模型，检测指标包括：（1）心肌细胞形态；（2）心肌细胞存活率；（3）超氧化物歧化酶（SOD）活性；（4）丙二醛（MDA）含量；（5）乳酸脱氢酶（LDH）活性。结果-模型组缺氧后心肌细胞存活率降低，复氧30min后进一步下降，各个时间点细胞内SOD活性下降，MDA含量升高，LDH活性升高，与正常组比较差异有统计学意义（P〈0．01），复氧60min后各指标逐渐趋于正常状态；DADLE 1μmaol／L组细胞存活率升高，LDH活性降低，MDA含量逐渐趋于正常，SOD活性逐渐回升，表明经DADLE干预后，心肌细胞抗损伤能力加强，发生损伤的程度减轻；δ阿片受体抑制剂纳曲吲哚10μmol／L抑制DADLE的保护作用。结论：DADLE通过δ阿片受体对乳鼠心肌细胞H／R损伤具有保护作用。     

Pim-3基因转染对心肌缺氧／复氧损伤的保护作用

目的：克隆原癌基因Pim-3并构建其GFP表达质粒，探讨Pim-3对心肌细胞遭受缺氧／复氧损伤时所起的保护作用。方法：采用RT-PCR从Wistar大鼠心肌组织中提取并克隆Pim3基因，经酶切和连接反应构建GFP表达质粒，分别为pEGFP-N2-Pim-3质粒和pEGFP-N2（空载质粒），经脂质体转染人原代培养的心肌中，随机分为七组，分别为对照组、对照＋pEGFP-N2组、对照＋pEGFP-N2-Pim-3组、缺氧复氧损伤组、缺氧复氧损伤＋pEGFP-N2组、缺氧复氧损伤＋pEGFPN2-Pim-3组、缺氧预适应处理组。实验结束时全自动生化仪检测培养液中乳酸脱氢酶（LDH）活性、四唑盐（MTT）比色试验测定细胞存活率、TUNEL法与P1-An-nexin V法测定心肌细胞凋亡、流式细胞仪测定心肌细胞线粒体膜电位（△ψm），并且测定Pim-3 mRNA及蛋白表达水平（RT-PCR、Western-blotting法）的改变。结果：经酶切证实和测序鉴定，成功克隆大鼠Pim-3基吲，并且细胞转染效率达15％；在缺氧复氧损伤后，pEGFP-N2-Pim-3转染组较pEGFP-N2转染组／未转染组的LDH值明显降低（p〈0．01），细胞存活率则明显升高（P〈0．01），凋亡细胞明显减少（P〈0．01），线粒体膜电位（△皿m）则明显升高（P〈0．01）；电镜结果表明转染了pEGFP-N2-Pim-3的心肌细胞线粒体膜大都完整，嵴清晰，较之pEGFP-N2转染组／未转染组损伤明显减轻；RT-PCR和Western-blotting结果显示，Pim-3在正常组几乎不表达，缺氧复氧损伤组明显升高（p〈0．01），缺氧预处理组的表达则比缺氧复氧损伤组更为升高（P〈0．05）。结论：外源性Pim-3基因转染人心肌细胞，对心肌细胞的缺氧／复氧损伤具有明显的保护作用。     

山楂酸对体外乳大鼠心肌细胞损伤的保护作用

［摘要］　目的：观察在缺氧复氧以及钙超载模型下，山楂酸对体外乳大鼠原代心肌细胞是否具有保护作用。方法：采用Na2S2O4致心肌细胞缺氧并复氧以及异丙肾上腺素致心肌细胞钙超载模型，测定培养液中乳酸脱氢酶（LDH）和肌酸激酶（CK）活性，并检测心肌细胞的存活率。结果：在Na2S2O4致心肌细胞缺氧复氧模型中，缺氧复氧后1.5，3，15和24 h， MA 3×10-6和3×10-7 mol&#8226;L-1组细胞培养液中CK和LDH活性均明显减少（P<0.01，P<0.05）；在异丙肾上腺素致心肌细胞钙超损伤载模型中，异丙肾上腺素作用30 h时山楂酸3×10-6和3×10-7 mol&#8226;L-1组心肌细胞细胞存活率显著提高，培养液中CK和LDH活性均明显减少。结论：山楂酸对心肌细胞损伤的保护作用可能与其抗氧化和抑制细胞内钙超载有关。     

白细胞介素-1预适应对心肌缺血再灌注损伤的保护作用及机制

目的 :观察低剂量白细胞介素 1β(IL 1β)预适应能否诱导心肌延迟保护作用的产生 ,并探讨其发生机制。方法 :在大鼠心肌缺血预适应和培养心肌细胞缺氧预适应模型上 ,分别设缺血或缺氧预适应组、IL 1β 预适应 (ILPC)组和缺血再灌注 (I/R )组或缺氧复氧 (A/R)组 ,检测预适应后即刻 ,12h ,2 4h细胞间粘附分子 (ICAM 1)和热休克蛋白72(HSP72 )表达 ,以及中性粒细胞 (PMN )浸润数和超氧化物歧化酶 (SOD)含量 ,并观察预适应 12h和 2 4h后心肌梗死范围和心肌细胞存活率的变化规律。结果 :ILPC组与I/R组比较 ,预适应后 2 4h大鼠心肌ICAM 1的表达、PMN浸润数明显减少 ,心肌梗死范围缩小 (P <0 .0 5或P <0 .0 1) ;与A/R组比较 ,预适应后 2 4h培养心肌细胞存活率、SOD含量、HSP72 表达均显著增加 (P <0 .0 5 ) ,而预适应后即刻无显著差异 (P >0 .0 5 )。结论 :低剂量ILPC和缺血或缺氧预适应能够诱导心肌延迟保护的发生 ;其发生机制除了与HSP72 表达和SOD含量增加有关外 ,且与ICAM 1表达下降 ,减少PMN浸润也有密切关系     

cyclinD1和CDK4在低氧心肌中的表达及意义

目的研究低氧心肌细胞周期及缺氧过程中细胞周期蛋白D1(cyclinD1)和细胞周期蛋白依赖激酶4(CDK4)表达的变化,探讨缺氧心肌在凋亡前是否存在增殖能力和自身修复。方法采用SD大鼠乳鼠进行心肌细胞培养,建立心肌缺血模型,实验分正常对照、缺血6 h和缺血12 h三组;以四唑盐比色试验(MTT)检测心肌细胞活力,流式细胞术测定细胞周期,免疫组化检测cyclinD1和CDK4表达。结果与对照组比较,心肌细胞缺氧处理6 h后,细胞周期中S 期比例增高(P<0 01),12 h后,S期比例下降(P<0 05);cyclinD1胞浆表达和CDK4 胞核表达增加。结论在缺氧所致死亡、凋亡过程中心肌细胞经历了一定程度的增殖过程,cyclinD1 和CDK4 表达增加参与了细胞增殖,缺氧损伤可刺激心肌细胞增殖能力。     

1-磷酸鞘氨醇后适应对H9c2心肌细胞缺氧/复氧损伤的保护作用

目的 研究1-磷酸鞘氨醇（S1P）后适应对H9c2心肌细胞缺氧复氧损伤的保护作用,并探讨其作用机制。方法 将培养的H9c2心肌细胞随机分为5组,即①正常（Con）组;②缺氧/复氧（H/R）组;③S1P低浓度（L）组;④S1P中浓度（M）组;⑤S1P高浓度（H）组。测定各组H9c2心肌细胞的存活率; 收集细胞培养液测定超氧化物歧化酶（SOD）活性和丙二醛（MDA）含量;流式细胞仪检测心肌细胞凋亡百分率;Fura 2-AM标记细胞内游离钙离子,检测荧光强度以反映细胞内游离钙离子浓度的变化;Western Blot法测定保护性蛋白热休克蛋白70 （HSP70）的表达情况。结果 对于H/R 损伤的H9c2心肌细胞,S1P能够提高细胞的存活率,降低细胞内MDA含量及细胞内钙离子浓度,提高细胞内SOD活力,增强抗凋亡蛋白HSP70的表达,且呈一定的浓度依赖性。结论 S1P可以减轻心肌细胞氧化应激损伤,改善心肌细胞活力并减少凋亡。S1P对心肌细胞的保护作用可能是通过减少Ca2 超负荷,增加抗凋亡蛋白HSP70表达来实现的。     

七氟醚对兔肺缺血再灌注损伤超微结构改变的影响

目的：观察七氟醚对兔肺缺血再灌注损伤超微结构的影响，并探讨其可能机制。方法：72只日本大耳白兔，随机均分为4组（n=18）：假手术组（S组）、缺血再灌注组（IR组）、七氟醚-缺血再灌注组（Sev—IR组）和七氟醚组（Sev—S组）。S组开胸游离左肺门后，未行缺血再灌注。IR组、Sev—IR组参照Eppinger方法建立肺缺血再灌注模型，Sev—IR组吸入30min1肺泡最小有效浓度（MAC）七氟醚后行缺血再灌注，Sev—S组吸入30min 1MAC七氟醚后不进行缺血再灌注。分别在缺血45min、再灌注60、120min处死兔，使用电子显微镜观察各组不同时间点肺组织超微结构的变化。并在再灌注120min测各组髓过氧化物酶（MPO）的活性。结果：电镜下IR组肺泡毛细血管内皮细胞、工型肺泡上皮细胞水肿变性，肺泡壁增厚，Ⅱ型肺泡上皮细胞膜微绒毛减少，线粒体肿胀、嵴减少，且胞质中板层小体明显减少，肺间质水肿，毛细血管腔内中性粒细胞（PMN）堵塞。Sev—IR组毛细血管内PMN附壁减少，Ⅰ型肺泡上皮细胞内吞饮小泡增加，Ⅱ型肺泡上皮细胞表面微绒毛增多。在再灌注120min时，IR组和Sev—IR组肺组织MPO的活性明显高于S组（P〈0．01），而Sev—IR组MPO的活性低于IR组（P〈0．05）。结论：七氟醚对兔肺缺血再灌注损伤引起的超微结构改变有一定改善作用，其机制可能与降低PMN在肺脏的聚集有关。     

中华眼镜蛇毒组分F/H对大鼠心肌细胞缺氧-再给氧损伤的作用探讨

以Laarse方法建立大鼠心肌细胞缺氧-再给氧模型．缺氧缺糖60min．再给氧1h．探讨组份F和H对实验性心肌细胞缺血再灌注的保护作用。实验结果显示,缺氧后心肌细胞成活率显著减少,心肌释放LDH含量显著增加．细胞膜流动性下降,缺氧再给氧后上述各指标改变加剧。组份F和H能明显提高心肌细胞成活率,减少LDH的释放．增加细胞膜流动性．减少心肌细胞膜的损伤,实验结论,组份F和H有明显抗心肌细胞缺氧-再给氧损伤的作用,尤以组份F作用更显著。     

Efficacy of gut lavage,hemodialysis, and hemoperfusion in the therapy of paraquat or diquat intoxication

Clinical and in vitro investigations were carried out to test the efficacy of gut lavage, hemodialysis, and hemoperfusion in the treatment of poisoning with paraquat or diquat. In a patient suffering from diquat intoxication 130 times more diquat was removed by gut lavage 30 h after ingestion than was removed by complete aspiration of the gastric contents.Determination of in vitro clearances for paraquat and diquat by hemodialysis showed that, at serum concentrations of 1–2 ppm, such as are frequently encountered in poisoning in man, toxicologically relevant quantities of herbicide cannot be removed from the body. At a concentration of 20 ppm, on the other hand, hemodialysis proved to be effective, the clearance being 70 ml/min at a blood flow rate of 100 ml/min. The efficacy of hemoperfusion with coated activated charcoal was on the whole better. Especially at concentrations around 1–2 ppm, the clearance values for hemoperfusion were some 5–7 times higher than those for hemodialysis.In a patient suffering from paraquat poisoning, both hemodialysis as well as hemoperfusion were carried out. The in vitro results could be confirmed: At serum concentrations of paraquat less than 1 ppm no clearance could be obtained by hemodialysis while by hemoperfusion with activated charcoal quite high clearance values were measured and the serum level dropped down to zero.

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Zusammenfassung Klinische Untersuchungen und Laboratoriumsversuche wurden durchgeführt, um die Wirksamkeit von Darmspülung, Hämodialyse und Hämoperfusion bei Paraquat- und Deiquat-Vergiftungen zu prüfen.Bei einem Patienten wurde 30 Std nach Deiquat-Aufnahme durch Darmspülung 130mal mehr Deiquat entfernt als durch vollständige Aspiration des Mageninhaltes. In vitro-Versuche ergaben, daß bei Blutserumkonzentrationen von 1–2 ppm, die bei Vergiftungen oft gemessen werden, durch Hämodialyse keine toxikologisch relevanten Paraquat- oder Deiquat-Mengen entfernt werden können. Dagegen erwies sich die Hämodialyse bei 20 ppm und einer Blutumlaufgeschwindigkeit von 100 ml/min mit einer Clearance von 70 ml/min als wirksam. Die Hämoperfusion mit beschicheter Aktivkohle war in diesen Versuchen aber eindeutig überlegen, denn insbesondere bei Konzentrationen um 1–2 ppm waren die Clearance-Werte 5–7mal höher als bei der Hämodialyse.Die in vitro-Ergebnisse wurden bei einem Patienten mit einer Paraquat-Vergiftung bestätigt: Bei Konzentrationen unter 1 ppm war die Hämodialyse wirkungslos, während durch Hämoperfusion relativ hohe Clearance-Werte erreicht wurden, so daß der Serumspiegel rasch unter die Nachweisgrenze abfiel.

     

In vitro studies on sterically stabilized liposomes (SL) as enzyme carriers in organophosphorus (OP) antagonism

This study describes a new approach for organophosphorous (OP) antidotal treatment by encapsulating an OP hydrolyzing enzyme, OPA anhydrolase (OPAA), within sterically stabilized liposomes. The recombinant OPAA enzyme was derived from Alteromonas strain JD6. It has broad substrate specificity to a wide range of OP compounds: DFP and the nerve agents, soman and sarin. Liposomes encapsulating OPAA (SL)* were made by mechanical dispersion method. Hydrolysis of DFP by (SL)* was measured by following an increase of fluoride ion concentration using a fluoride ion selective electrode. OPAA entrapped in the carrier liposomes rapidly hydrolyze DFP, with the rate of DFP hydrolysis directly proportional to the amount of (SL)* added to the solution. Liposomal carriers containing no enzyme did not hydrolyze DFP. The reaction was linear and the rate of hydrolysis was first order in the substrate. This enzyme carrier system serves as a biodegradable protective environment for the recombinant OP-metabolizing enzyme, OPAA, resulting in prolongation of enzymatic concentration in the body. These studies suggest that the protection of OP intoxication can be strikingly enhanced by adding OPAA encapsulated within (SL)* to pralidoxime and atropine.     

Aquatic Insects and Trace Metals: Bioavailability,Bioaccumulation, and Toxicity

Abstract

The uptake of metals from food and water sources by insects is thought to be additive. For a given metal, the proportions taken up from water and food will depend both on the bioavailable concentration of the metal associated with each source and the mechanism and rate by which the metal enters the insect. Attempts to correlate insect trace metal concentrations with the trophic level of insects should be made with a knowledge of the feeding relationships of the individual taxa concerned. Pathways for the uptake of essential metals, such as copper and zinc, exist at the cellular level, and other nonessential metals, such as cadmium, also appear to enter via these routes. Within cells, trace metals can be bound to proteins or stored in granules. The internal distribution of metals among body tissues is very heterogeneous, and distribution patterns tend to be both metal and taxon specific. Trace metals associated with insects can be both bound on the surface of their chitinous exoskeleton and incorporated into body tissues. The quantities of trace meals accumulated by an individual reflect the net balance between the rate of metal influx from both dissolved and particulate sources and the rate of metal efflux from the organism. The toxicity of metals has been demonstrated at all levels of biological organization: cell, tissue, individual, population, and community. Much of the literature pertaining to the toxic effects of metals on aquatic insects is based on laboratory observations and, as such, it is difficult to extrapolate the data to insects in nature. The few experimental studies in nature suggest that trace metal contaminants can affect both the distribution and the abundance of aquatic insects. Insects have a largely unexploited potential as biomonitors of metal contamination in nature. A better understanding of the physico-chemical and biological mechanisms mediating trace metal bioavailability and exchange will facilitate the development of general predictive models relating trace metal concentrations in insects to those in their environment. Such models will facilitate the use of insects as contaminant biomonitors.     

Alzheimer’s disease – current trends in basic and clinical research. Highlights from the 16th ECNP

Advances in the molecular biological knowledge of neuronal nicotinic acetylcholine receptors (nAChRs) have led to a growing interest by the pharmaceutical industry in the development of novel compounds that selectively modulate nAChR function. The ability of (-)-nicotine, an activator of nAChRs, to enhance attentional aspects of cognition in animals and humans, to exert neuroprotective and anxiolytic-like effects, and presumably to mediate the negative correlation between smoking and Alzheimer's (and Parkinson's) Disease, has focused interest on the potential therapeutic utility of modulators of nAChR function for treatment of some of the deficits associated with these progressive, neurodegenerative conditions. Numerous compounds are known which activate nAChRs and which might serve as lead compounds toward the development of such agents. The pharmacologic diversity of neuronal nAChR subtypes suggests the possibility of developing selective compounds which would have more favourable side-effect profiles than existing agents. This broader class of agents, collectively called cholinergic channel modulators (ChCMs), is anticipated to encompass compounds which would have more favourable side-effect profiles than existing agents, which generally exhibit low selectivity. This selectivity may be achieved by preferentially activating some subtypes of nAChRs (i.e., Cholinergic Channel Activators, ChCAs) or inhibiting the function of other subtypes (Cholinergic Channel Inhibitors, ChCIs). An overview of the biology of nAChRs and the rationale for the use of ChCMs for the treatment of dementia related to neurodegenerative diseases are presented, followed by a discussion of lead compounds and compounds under consideration for clinical evaluation.     

Steroidal sapogenin contents in some domestic plants

In order to find out the values of the steroid resources for the future use. the compositions and contents of steroidal sapogenins from 13 domestic plants have been investigated. As a result,Dioscorea nipponica, D. quinqueloba andSmilax china were found to have large amount of diosgenin. And pennogenin inTrillium kamtschaticum andParis verticillata, yuccagenin inAllium fistulosum, hecogenin inAgave americana and neochlorogenin inSolanum nigum were appeared to be major steroidal sapogenins.