左旋精氨酸含血停搏液对未成熟心肌的保护效果

目的探讨左旋精氨酸加入ThomasⅡ停搏液对未成熟心肌的保护效果。方法2～3周龄新西兰大白兔20只，随机分为2组，每组10只。建立Langendoff离体心脏灌注模型。对照组：ThomasⅡ号停搏液灌注加低温；实验组：左旋精氨酸加入ThomasⅡ号停搏液灌注并行低温。全心平均停循环90min，再灌注30min。观察指标：冠脉流量恢复率(CFR)、心肌丙二醛(MDA)／超氧化物岐化酶(SOD)含量、心肌三磷酸腺苷(ATP)含量、心肌磷酸肌酸激酶(CK)漏出量和乳酸脱氢酶(LDH)漏出量。结果再灌注末实验组心肌MDA含量低于对照组，而SOD含量高于对照组；实验组CFA和再灌注末心肌ATP含量高于对照组；实验组心肌含水量、CK和LDH漏出量低于对照组。结论左旋精氨酸加入含血ThomasⅡ号停搏液中可改善未成熟心肌的保护作用。     

不同浓度L-精氨酸对婴幼儿室间隔缺损修补术心肌缺血/再灌注损伤的影响

目的 探讨不同浓度L-精氨酸(L-Arg)加入心脏停搏液对婴幼儿心肌缺血/再灌注的影响.方法 择期行室间隔缺损(VSD)修补术患儿48例,随机分为对照组(C组,n=16)、L-Arg I组(L1组,n=16)和L-Arg II组(L2组,n=16).L1组停搏液中加入2.5 g/L的L-Arg ,L2组停搏液中加入5 g/L的L-Arg ,C组停搏液中加入相同容积的生理盐水.分别于诱导后(基础值,T0 )、主动脉开放5 min(T1)、主动脉开放30 min(T2)、停体外循环(CPB)4 h(T3)、停CPB 24 h(T4)抽取动脉血,测血浆心肌肌钙蛋白I(cTnI)、丙二醛(MDA)、超氧化物歧化酶(SOD)水平.结果 3组再灌注后血浆cTnI、MDA浓度均显著升高(P＜0.01),而SOD活性显著降低(P＜0.01或P＜0.05).L1组cTnI、MDA升高幅度低于C组,SOD降低幅度低于C组(P＜0.05或P＜0.01).L2组与C组比较无明显差异(P＞0.05).结论 含L-Arg 2.5 g/L的心脏停搏液对婴幼儿心肌缺血/再灌注损伤有保护作用,含L-Arg 5 g/L的心脏停搏液对这种损伤无明显影响.     

3,4-二羟基苯乙酮对心肌保护作用的研究

目的研究心肌3,4-二羟基苯乙酮(青心酮)预处理和缺血预处理对离体大鼠心脏缺血/再灌注后心肌功能的影响。方法以离体大白鼠工作心脏模型,比较经青心酮预处理和缺血预处理,心肌缺血再灌注前后左室压(LVP)、左室舒张末期压(LVDEP)、左心室内压上升及下降最大速率(±dt/dpmax)、主动脉压(AP)、冠脉流量(CF)、主动脉流量(AF)和测定冠脉流出液乳酸脱氢酶(LDH),心肌三磷酸腺苷(ATP)含量及自灌注停搏液至完全停搏的时间(AT)。结果青心酮预处理和缺血预处理产生相似的心肌保护作用,明显促进心肌缺血再灌注后心肌功能的恢复,增进心脏的收缩功能、心肌ATP含量。结论青心酮预处理模拟体外循环的缺血再灌注损伤具有保护作用,该方法有临床应用价值。     

L-肉碱预处理对离体家兔心肌缺血再灌注损伤的保护作用

目的:观察L-肉碱预处理对离体家兔心肌缺血再灌注损伤的保护作用.方法:采用离体兔心Langendorff灌注实验模型,离体兔心24只,随机等分成3组(n=8).正常对照组:连续灌注K-H液 90 min;缺血再灌注损伤组:灌注 30 min,关闭主动脉套管停止灌注,30 min后恢复37 ℃ K-H液灌注 60 min;L-肉碱组:步骤同缺血再灌注组,但在停灌前先用含10 mmolL-1 L-肉碱的K-H液灌注 30min.记录血流动力学指标:冠脉流量(CF)、左心室舒张压(LVDP)、左心室压力时间变化率(±dp/dt);检测冠脉流出液中丙二醛(MDA)、超氧化物歧化酶(SOD)、肌酸激酶(CK)、乳酸脱氢酶(LDH)浓度和心肌组织中MDA、SOD及L-肉碱的含量.结果:L-肉碱组能显著促进再灌注时心功能恢复:±dp/dtmax和LVDP显著升高;CF增大;冠脉流出液中MDA、LDH、CK以及心肌组织中MDA浓度降低;而冠脉流出液和心肌组织中SOD含量均升高(P<0.05);心肌中L-肉碱含量明显增高(P<0.01);超微结构观察结构损伤较轻(P<0.05).结论:L-肉碱预处理具有抗兔离体心肌缺血再灌注损伤的作用.     

异丙酚对离体大鼠缺血/再灌注心肌丙二醛和含水量的影响

目的 :探讨异丙酚对离体大鼠缺血 /再灌注心肌丙二醛 (MDA)和水肿程度的影响。方法 :采用改良Langendorff离体大鼠心脏模型 ,将 2 4只大鼠随机分成 4组。正常对照组 :用K H液持续灌注 80min ;缺血 /再灌注模型组 :用K H液预灌 30min ,然后用4℃的St.Thomas停搏液使心脏停跳 ,常温下全心停灌 2 0min ,K H液再灌注 30min ;异丙酚组和异丙酚 +格列本脲组 :从预灌第 15min改用含相应药液的K H液灌注 ,停灌同缺血 /再灌注模型组 ,然后用含相应药液的K H液再灌注 30min。测定心肌含水量、MDA含量和冠脉流出液肌酸激酶 (CK)活性。结果 :缺血再灌注可使心肌含水量、MDA含量和CK活性明显增高 (P <0 .0 1) ,30 μmol·L- 1异丙酚能显著减轻上述损伤性变化 ,格列本脲对异丙酚的心肌保护作用无影响 (P >0 .0 5 )。结论 :心肌缺血 /再灌注可致心肌水肿 ,异丙酚减轻水肿作用与其抗氧化有关 ,而与ATP 敏感性钾通道的开放无关     

左西孟旦对大鼠离体心脏缺血再灌注损伤的保护作用

目的:观察含左西孟旦(Levo)的停搏液对大鼠离体缺血再灌注心肌的保护作用。方法:32只雄性Wistar大鼠随机分为L0、L0.03、L0.3、LG共4组,每组8只,在去极化停搏液STH-2中分别加入Levo0、0.03、0.3μmol/L以及Levo0.3μmol/L+格列苯脲10μmol/L。平衡灌注30min后分别用25℃的4种不同停搏液停搏,2h后重新灌注30min,观察对比各组停搏前后不同时间点心功能指标、再灌注末冠脉流出液中乳酸脱氢酶(LDH)和肌酸激酶(CK)含量的不同。结果:各组心功能基础值差异无统计学意义(P>0.05),再灌注期各组心功能都有不同程度的降低,L0.3组左心室舒张末压(LVDP)、心室内压力上升/下降速率(±dp/dtmax)的恢复率均高于其他3组(P<0.01或P<0.05),HR的恢复率明显高于L0组(P<0.01),L0.03组、LG组与L0组比较心率(HR)、+dp/dtmax的恢复率差异无统计学意义(P>0.05),-dp/dtmax恢复率在T2时点高于L0组(P<0.05或P<0.01)。再灌注末CK和LDH漏出量L0.3组明显低于其他各组(P<0.05或P<0.01)。结论:Levo加入STH-2停搏液能够明显减轻缺血再灌注心肌的损伤。     

参麦注射液对正常及缺血再灌注离体豚鼠心脏的影响

目的观察参麦注射液(SM)对正常及缺血再灌注离体豚鼠心脏的影响。方法采用正常Langendorff灌流及缺血再灌注离体豚鼠心脏模型,观察SM对冠脉流量的影响,测定冠脉流出液中乳酸脱氢酶(LDH)活性及心肌组织丙二醛(MDA)、超氧化物歧化酶(SOD)的活性。结果SM可显著提高正常及缺血-再灌注离体豚鼠心脏的冠脉流量,减少缺血-再灌注后LDH的漏出总量,降低缺血再灌后心肌组织MDA的含量,升高SOD的活性。结论SM可增加正常及缺血-再灌离体豚鼠心脏冠脉流量,减轻缺血-再灌引起的心肌损伤。     

姜黄素对实验性缺血-再灌注损伤心肌能量代谢的影响

目的:探讨姜黄素对大鼠缺血-再灌注损伤心肌能量代谢的影响.方法:建立Langendorff灌注模型,将32只Wistar大鼠随机分为对照组和姜黄素组.对照组心脏停搏液用4℃St Thomas液;姜黄素组在4℃St Thomas液中加入姜黄素(0.2 mmol·L).分别于缺血前及再灌注30 min后,检测心脏血流动力学指标、心肌线粒体超氧化物歧化酶(SOD)、丙二醛(MDA)含量.31P-核磁共振分光仪检测心肌磷酸肌酸(PCr)、磷酸盐(Pi)和β-ATP水平.透射电镜观察再灌注后线粒体超微结构.结果:姜黄素组心肌再灌注30 min后心脏血流动力学指标、心肌高能磷酸盐水平、线粒体MDA、SOD、线粒体超微结构等均明显优于对照组(P＜0.01).结论:姜黄素可显著改善大鼠缺血-再灌注损伤心肌的能量代谢,与其增强心肌线粒体内源性抗氧化能力,维持线粒体结构的完整性有关.     

左-卡尼汀心停搏液对犬体外循环心肌的保护作用

目的研究左-卡尼汀(L-CN)心停搏液冠状动脉间断顺行灌注对犬体外循环(CPB)心肌的保护作用。方法20只♂健康成年杂种犬,随机分为实验组和对照组,每组n=10。实验组术中于4℃ST.Thomas Ⅱ心停搏液中按12g·L-1加入L-CN;对照组以等量生理盐水代替L-CN加入ST.Thomas Ⅱ号冷晶体液作为心停搏液,其它条件同治疗组。升主动脉每阻断30min灌注1次,共4次,末次灌注液中氯化钾浓度减半。结果①升主动脉阻断时,两组冠状静脉窦血清心肌肌钙蛋白I(cTnI)、肌酸激酶MB同工酶(CK-MB)水平,左心室心肌丙二醛(MDA)和三磷酸腺苷(ATP)含量以及超氧化物歧化酶(SOD)活性比较差异无统计学意义(P>0.05);升主动脉开放时,实验组cTnI、CK-MB和MDA均低于对照组(P<0.05或P<0.01),SOD和ATP则高于对照组(P<0.05)。②与对照组比较,实验组术毕心脏自动复跳率明显升高(P<0.01)。③Western blot法分析腺苷二磷酸-核糖多聚酶(PARP)的裂解情况,两组术毕心肌均有PARP完整的113ku被水解为89ku的片段,但实验组被水解的PARP完整片段明显少于对照组。结论L-CN心停搏液通过改善CPB心肌的能量代谢,降低心肌细胞毒性产物的生成,减少心肌细胞凋亡,从而达到较好的心肌保护作用。     

咖啡酸苯乙酯对大鼠离体心脏心肌缺血再灌注的保护作用北大核心CSCD

目的建立大鼠离体心脏心肌缺血再灌注模型,初步探讨咖啡酸苯乙酯对离体心脏心肌缺血再灌注损伤的保护作用。方法雄性SD大鼠30只,取心脏Langendorff法离体灌流,实验分5组:空白组:KH(Krebs-Henseleit)液连续灌流100 min;模型组:KH液稳灌30 min后停灌30 min,再灌注KH液40 min;给药组:KH液稳灌30 min后,停灌30 min,再灌注3、6和12 mg/L CAPE的KH液40min。实验中观察各组大鼠离体心脏的冠脉流量、心肌收缩力及心率的变化。停灌后测其各组心肌组织的丙二醛(MDA)、蛋白羰基化(PCO)的含量和超氧化物歧化酶(SOD)活性。结果心脏缺血再灌注期间,模型组收缩力减弱,张力增加,心率减慢,冠脉流量明显减少,出现心律失常;给药组在再灌注后收缩力增强,张力降低,心率增快,冠脉流量明显增加,节律整齐。停灌后模型组MDA、PCO含量明显升高,SOD含量降低,而给药组MDA、PCO的含量较模型组减少(P<0.01),且减少SOD含量的降低(P<0.01)。说明缺血再灌注能够增加心脏的氧化应激,诱导氧化损伤,CAPE保护可以减少氧化损伤,且呈剂量依赖性。结论咖啡酸苯乙酯对大鼠离体心脏缺血再灌注损伤具有保护作用,其机制可能与抗氧化作用有关。     

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.