葛根素对心肌缺血再灌注损伤的保护作用

目的　探讨葛根素对心肌缺血再灌注损伤的保护作用,并初步探讨其作用机制。方法　19只家兔随机分为3组:①假手术组(S组,n=6) :开胸,左冠状动脉前降支(LAD)只穿线不结扎,旷置20min ,再观察6h ;②缺血/再灌注组(IR组,n=7) ;③葛根素治疗组(P组,n=6 ) :两组均开胸结扎兔LAD2 0min ,然后松扎6h。以电镜下心肌超微结构、心率、再灌注心律失常、左室功能、右室血清SOD活性和MDA的含量及心肌组织中SOD ,MDA ,ATP水平为观察指标。结果　3组心率均呈进行性下降趋势,其中IR组下降幅度最大。P组左室内压力上升和下降速率及左室内压峰值均显著高于IR组(P<0.01) ,血清及心肌组织中SOD活性和心肌组织中ATP含量显著高于IR组(P<0.01) ,而MDA含量明显低于IR组(P<0.01) ,再灌注心律失常发生率低于IR组(P<0.01) ,P组心肌超微结构损害较轻。与S组比较,P组上述各指标均无显著差异(P>0.05)。结论　葛根素可促进心肌缺血/再灌注损伤心功能的恢复,其作用机制可能与清除氧自由基、改善心肌能量代谢等有关     

左-卡尼汀预处理对缺血再灌注大鼠心肌的保护作用

目的 探讨左-卡尼汀(L-CN)预处理对大鼠心肌缺血再灌注损伤(MIRI)的心肌保护作用及其可能的机制.方法 36只Wistar大鼠随机分为3组,每组n=12.左-卡尼汀治疗组(L-CN):术前给予L-CN 200 mg·kg-1·d-1腹腔注射给药5天;缺血-再灌注组(IR):术前给予等量生理盐水腹腔注射5天;假手术组(P):术前处理同IR组.L-CN和IR两组大鼠在心电监护下结扎左前降支(LAD)30 min后松开结扎线,恢复心肌血流灌注3 h后处死动物,P组除LAD仅穿线不结扎外,所有操作同前两组.(1)三组均于术前和处死动物前从颈动脉抽血观察血浆肌酸激酶、MB同工酶(CK-MB)、丙二醛(MDA)含量及超氧化物歧化酶(SOD)活性.(2)实验结束处死大鼠前留取心肌标本,光镜下观察心肌病理学改变,TUNEL法测定心肌细胞的凋亡指数.结果 (1)动物处死前,IR组MDA、CK-MB高于L-CN组(P＜0.01),而SOD低于L-CN组(P＜0.01).(2)IR组心肌细胞凋亡指数明显高于L-CN组(P＜0.05).(3)组织形态学观察(HE):IR组心肌纤维水肿、大部分断裂;L-CN组心肌纤维扭曲,但结构基本完整.结论 L-CN预处理对大鼠MIRI具有一定的保护作用,其机制可能是通过抑制心肌脂质过氧化、减少心肌细胞凋亡.     

血塞通注射液对缺血再灌注心肌的保护作用

目的 探讨血塞通注射液对大鼠心肌缺血再灌注损伤的保护作用.方法 将24只Wistar大鼠随机分为三组:心肌缺血再灌注组(MIR,n=8):术前给予生理盐水干预;血塞通治疗组(X,n=8):术前给予血塞通注射液600 mg/(kg·d)腹腔注射给药3天;假手术组(S,n=8):术前处理同MIR组.MIR和X组大鼠在结扎左前降支30分钟后行再灌注240分钟.S组所有操作同MIR组,大鼠仅穿线不结扎左前降支.分别于缺血再灌注240分钟采血,S组取相同时点采血.检测血清超氧化物歧化酶(SOD)活性、丙二醛(MDA)和肌钙蛋白I(cTnI)含量变化.结果 与X组和S组比较,MIR组血清SOD活性显著降低(P＜0.001),MDA、cTnI含量显著升高(P＜0.001);与S组比较,X组血清SOD、MDA浓度差异无显著性(P＞0.05),而血清cTnI显著升高(P＜0.01).结论 血塞通可能通过减少MDA的产生,增加SOD活性,减轻心肌缺血再灌注损伤.     

莲心碱对大鼠缺血再灌注损伤心肌的保护作用

目的:研究莲心碱对大鼠缺血再灌注损伤心肌的保护作用.方法:实验大鼠24只,随机分为3组,每组8只.假手术组:冠状动脉左前降支(LAD)处穿一丝线,但不结扎;损伤对照组:结扎冠状动脉LAD,造成心肌缺血再灌注损伤;药物组:结扎冠状动脉LAD前静脉注射莲心碱5 mg&#8226;kg 1.测定每组大鼠血清中磷酸肌酸激酶(CPK)、乳酸脱氢酶(LDH)活性,丙二醛(MDA)含量,心肌梗死范围(IS).结果:与假手术组和损伤对照组比较,药物组血清CPK、LDH活性与MDA含量明显降低(P＜0.01),心肌梗死面积减少(P＜0.05).结论:莲心碱对大鼠缺血再灌注损伤心肌有保护作用.     

冠心宁注射液对大鼠心肌缺血再灌注损伤的保护作用

目的:观察冠心宁注射液对大鼠心肌缺血再灌注损伤的保护作用,探讨冠心宁抗心肌缺血再灌注损伤的保护机理.方法:雄性SD大鼠30只随机分成假手术组(C组)、缺血再灌注组(I/R组)、冠心宁治疗组(G组),建立大鼠在体心肌缺血再灌注模型:C组丝线穿过冠状动脉前降支但不结扎,I/R、G组通过结扎心脏左冠状动脉前降支40 min,再灌注60 min制作缺血再灌注损伤动物模型.缺血前30 min,G组经腹腔注射冠心宁注射液10.0 ml·kg-1,余两组注射等量0.9%氯化钠注射液.测定再灌注60 min后心肌超氧化物岐化酶(SOD)活性及丙二醛(MDA)含量,同时取每组大鼠心肌检测梗死面积,电镜下观察缺血区心肌超微结构变化.结果:与I/R组相比,G组再灌注后60 min心肌MDA含量降低(P<0.01),SOD活性增高(P<0.01),梗死面积较小(P<0.01),心肌超微结构受损较轻.结论:冠心宁注射液对心肌缺血再灌注损伤有明显的保护作用,其机制与其增强心肌抗氧化作用有关.     

黄芪预处理对缺血再灌注大鼠心肌脂质过氧化、超微结构的影响

目的:探讨黄芪预处理对缺血再灌注大鼠心肌细胞超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、丙二醛(MDA)、超微结构的影响。方法:将大鼠随机分为假手术组、缺血组、缺血再灌注组和黄芪预处理组(黄芪组)。采用结扎大鼠左冠状动脉前降支法制备心肌缺血再灌注模型。测定各组大鼠心肌组织中SOD、GSH-Px活性及MDA浓度;用透射电镜观察心肌细胞的超微结构,通过图像分析系统对线粒体进行形态计量分析。结果:黄芪组GSH-Px活性及MDA含量分别高于和低于缺血再灌注组(P<0.01),SOD变化不明显;心肌细胞超微结构损害减轻,线粒体平均面积、平均周径减小,显著低于缺血再灌注组(P<0.05)。结论:结果提示黄芪预处理可以减轻大鼠心肌缺血再灌注损伤,可能是通过黄芪稳定心肌细胞膜和线粒体结构和功能来实现的。     

mitoK(ATP)介导硫化氢预处理延迟相的心肌保护效应

目的:研究线粒体ATP敏感性钾通道[mitoK(ATP)]激活在硫化氢预处理延迟相对大鼠心肌细胞的保护效应。方法:将32只健康成年雄性SD大鼠随机分成假手术组(Sham组)、缺血再灌注组(IR组)、硫化氢预处理组(HS组)和5-羟葵酸(5-HD)+硫化氢预处理组(HD组),每组8只。Sham组仅穿线但不阻断左冠状动脉前降支(LAD);IR组结扎LAD30min,松解后再灌注120min;HS组静脉注射硫化氢供体NaHS50μg/kg,24h后同IR组处理;HD组于结扎前15min静脉注射5-HD5mg/kg,其他同HS组处理。检测心室面积、心肌缺血面积和梗死面积,计算缺血和梗死面积百分比;电镜下观察心肌细胞超微结构。结果:3组缺血面积百分比差别无统计学意义(P>0.05);HS组心肌梗死面积百分比低于IR组和HD组(P<0.01或P<0.05),HD组与IR组相比差异无统计学意义(P>0.05)。心肌细胞超微结构损伤程度HS组较IR组明显减轻,而HD组与IR组差异不大。结论:硫化氢预处理延迟相可保护缺血再灌注损伤的心肌,mitoK(ATP)介导了硫化氢预处理延迟相的心肌保护通路。     

黄芩苷对大鼠心肌缺血再灌注损伤的保护作用(英文)

目的：研究中药有效成分黄芩苷(baicalin)对大鼠心肌缺血再灌注损伤的作用及其机制。方法：雄性Wistar大鼠随机分为4组,假手术组、对照组和黄芩苷50,100 mg·kg~(-1)组。结扎大鼠左冠状动脉前降支30 min后松开结扎线120 min复制心肌缺血-再灌注损伤模型,以多道生理记录仪持续记录左室压力变化速率(±dp/ dt_(max))和左室舒张末期压(LVEDP)的变化。检测心肌丙二醛(MDA)含量、超氧化物歧化酶(SOD)、Na~+-K~+-ATP酶和Ca~(2+)-ATP酶活性以及血清乳酸脱氢酶(LDH)和磷酸肌酸激酶(CK)含量,以透射电镜观察心肌超微结构的改变。结果：与假手术组比较,对照组大鼠左室±dp/dt_(max)明显降低(P＜0.01),而LVEDP明显升高(P＜0.01)。静脉注射黄芩苷50,100 mg·kg~(-1)可使降低的±dp/dt_(max)明显升高(P＜0.05,P＜0.01),升高的LVEDP显著降低(P＜0.05,P＜0.01)。黄芩苷组血清CK和LDH含量分别是(72±19)kU·L~(-1),(64±15)kU·L~(-1)和(1 365±209)U·L~(-1),(1 124±169)U·L~(-1),均明显低于对照组[(90±23)U·L~(-1)和(1 826±123)U·L~(-1),P＜0.01]。对照组大鼠心肌SOD,Na~+-K~+-ATP酶和Ca~(2+)-ATP酶活性均明显低于假手术组,而降低的酶活性可被预先给予黄芩苷所升高(P＜0.05,P＜0.01)。此外,黄芩苷还可降低缺血心肌MDA含量,改善心肌超微结构。结论：黄芩苷通过清除氧自由基,抗脂质过氧化,改善心肌ATP酶活性而保护心肌缺血再灌注损伤。     

参奇颗粒对心肌缺血再灌注损伤的保护作用

目的:研究参奇颗粒对心肌缺血再灌注损伤的保护作用以及作用机制.方法:采用冠脉结扎手术建立心肌缺血再灌注损伤模型,通过对大鼠血清中GSH-PX、SOD、MDA活性的影响以及对大鼠心肌梗死面积(MIS)和心肌细胞凋亡率的影响的测定来考察参奇颗粒对大鼠心肌缺血再灌注损伤的保护作用.结果:与假手术组比较,模型组能显著升高大鼠心肌血清中GSH-PX、SOD活性和心肌MPO活性(P＜0.05,P＜0.01,P＜0.01),能降低大鼠血清中MDA活性(P＜0.05),与模型组比较,参奇颗粒低、中、高剂量组均能升高大鼠血清中GSH-PX活性、SOD活性(P＜0.05,P＜0.01);参奇颗粒高、中、低剂量组均能降低大鼠血清中MDA活性(P＜0.01);参奇颗粒低、中、高剂量组能够降低大鼠心肌MPO活性(P＜0.05,P＜0.01);给药组低、中、高剂量组均能够降低心肌梗死程度差异显著(P＜0.05,P＜0.01),心肌细胞凋亡指数具有显著差异(P＜0.01),起到保护心肌的作用,效果呈现剂量依赖性.结论:参奇颗粒对大鼠心肌缺血再灌注损伤及作用机制研究具有一定的作用.     

参麦注射液对再灌注性大鼠心肌细胞保护的研究

目的:探讨参麦注射液对再灌注性大鼠心肌细胞保护的作用机制.方法:结扎冠状动脉前降支复制大鼠心肌缺血再灌注损伤模型,测定心肌组织丙二醛(MDA)含量及结构型、诱导型一氧化氮合酶(cNOS,iNOS)、超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、血清肌酸激酶(CK)的活性.结果:参麦注射液组心肌组织cNOS、SOD、GSH-Px活性高于缺血再灌注组(P＜0.01),MDA含量、iNOS及血清CK活性低于MI/R组(P＜0.01).结论:参麦注射液保护心肌再灌注性损伤的作用与其抑制iNOS活性、激活cNOS、提高心肌抗氧化能力、清除氧自由基、减轻细胞膜脂质过氧化状态相关.     

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.