参麦及缺血预处理对大鼠肝缺血再灌注损伤的保护作用

目的:研究参麦注射液及缺血预处理对肝缺血再灌注损伤的保护作用.方法:64只Wistar大鼠随机分成4组:假手术组(sham-operation,SO);缺血再灌注组(ischemia reperfusion,IR);缺血预处理组(ischemic preconditioning,IPC);参麦组(Shengmai injection,SM).建立肝脏缺血再灌注损伤模型.SO组行剖腹假手术;IR、IPC、SM组于再灌注60 min 、90 min时分别随机取8只大鼠检测血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、乳酸脱氢酶(LDH)和白细胞介素6(IL-6),同时取肝组织制成匀浆检测金属硫蛋白(MT),SO组于相应时点取样检测相同指标.分析比较各组计量资料.结果:SM组及IPC组在再灌注60 min、90 min时ALT、AST、LDH、IL-6水平均低于IR组(P＜0.01),而金属硫蛋白水平均高于IR组.结论:参麦及缺血预处理对肝缺血再灌注损伤具有保护作用.     

丹参注射液对大鼠脑缺血再灌注肝损伤影响的实验研究

目的研究丹参注射液对大鼠缺血再灌注肝损伤的影响。方法采用Pulsinelli方法建立大鼠急性全脑缺血再灌注模型。将Wistar大鼠随机分为3组,分别为对照组(A组)、缺血再灌注组(B组)、丹参+缺血再灌注组(C组),每组各9例。分别测定3组的血清ALT、AST、LDH的含量及肝组织超氧化物歧化酶(SOD)、丙二醛(MDA),观察肝细胞形态学变化。结果治疗组血清ALT、AST、LDH含量及肝组织MDA含量明显低于缺血再灌注组(P<0.01);肝组织SOD含量明显高于缺血再灌注组(P<0.01);肝细胞形态学变化明显减轻。结论丹参可以减轻大鼠脑缺血再灌注所致的肝脏损伤,对肝细胞有一定的保护作用。     

银杏内酯保护大鼠肝脏缺血/再灌注损伤作用的机制探讨

目的：观察银杏内酯对大鼠肝脏缺血再灌注损伤的影响，探讨其保护大鼠肝缺血再灌注损伤作用的机制。方法：通过大鼠60min缺血、2h再灌注损伤模型，应用硝酸酶还原法测定肝脏缺血前5min和再灌注后10min，30min血清NO水平变化；测定再灌注后2h血清ALT、AST、LDH酶学差异和肝组织内ATP、MDA含量变化；再灌注2h取肝组织完成肝细胞、肝小叶显微结构和超微结构的观察。结果：肝脏缺血再灌注损伤后血清NO水平降低，ALT、AST、LDH水平升高；银杏内酯能提高再灌注后血清NO水平，并对ALT、AST、LDH的病理性升高有降低作用，且能改善肝脏缺血再灌注损伤的微循环，减轻肝细胞内超微结构的损害程度。结论：银杏内酯对大鼠肝脏缺血再灌注损伤有保护作用，其作用机制可能是通过NO介导的。     

高渗盐水联合牛磺酸预处理对肝脏缺血再灌注损伤的保护作用

目的探讨高渗盐水（HS）联合牛磺酸（Tau）预处理对大鼠肝脏缺血再灌注损伤的保护作用及其作用机制。方法将30只健康雄性SD大鼠随机等分为五组：假手术组（A组）、缺血再灌注组（B组）、高渗盐水预处理组（C组）、牛磺酸预处理组（D组）和高渗盐水联合牛磺酸预处理组（E组）。参照Pringle法建立大鼠肝脏缺血再灌注损伤模型。再灌注6h后检测血清谷丙转氨酶（ALT）、谷草转氨酶（AST）、乳酸脱氢酶（LDH）、超氧化物歧化酶（SOD）和丙二醛（MDA）水平变化。结果缺血再灌注6h后显示反映肝脏损害程度的指标血清ALT、AST、LDH和MDA含量B、C、D和E组明显高于A组（P〈0.01）,C、D和E组明显低于B组（P〈0.01）,C组和D组明显高于E组（P〈0.05）,C组和D组之间差异无统计学意义（P〉0.05）;具有肝脏保护作用的指标血清SOD水平A、C、D和E明显高于B组（P〈0.01）,E组明显高于C组和D组（P〈0.01）,C组和D组之间差异无统计学意义（P〉0.05）。结论高渗盐水和牛磺酸分别预处理均可以改善大鼠肝脏缺血再灌注损伤,两药联合应用效果更好。     

纳洛酮预处理大鼠肝细胞对缺血再灌注损伤的影响

为探讨纳洛酮预处理大鼠后对其肝细胞缺血再灌注损伤的影响 ,短期对 Wistar大鼠腹腔内注射纳洛酮 ,然后制作缺血再灌注损伤模型 ,检测血清中谷丙转氨酶 (ALT)和谷草转氨酶 (AST)的含量 ,检测肝组织中丙二醛 (MDA)和超氧化物歧化酶(SOD)的含量 ,通过光镜、电镜观察 ,了解肝细胞形态学及超微结构的改变。结果显示 ,纳络酮预处理组血清中 AL T和 AST含量及肝组织中 MDA含量于缺血再灌注组 (P<0 .0 5 ) ,而肝组织中 SOD含量则高于缺血再灌注组 (P<0 .0 5 ) ,与假手术组无明显差异 ,肝细胞形态学异常改变也明显减轻     

阿托伐他汀钙及缺血后处理对大鼠肝缺血再灌注损伤保护效应的对比研究

目的观察大鼠肝缺血再灌注损伤时阿托伐他汀钙与缺血后处理对其保护效应的比较,并探讨其作用机制。方法 28只健康雄性SD大鼠随机分成假手术组(CON)、缺血再灌注组(IR)、缺血后处理组(IP0)、阿托伐他汀钙预处理组(APC),每组7只。建立大鼠70%的在体肝脏缺血再灌注模型,各组于最后灌注后经肝上下腔静脉取血,用于检测血清谷丙转氨酶(ALT)和谷草转氨酶(AST);取肝匀浆低温离心后采用试剂盒测定肝组织中总超氧化物歧化酶(TSOD)、丙二醛(MDA)、髓过氧化物酶(MPO)、一氧化氮(NO)、一氧化氮合酶(NOS)含量变化;同时取肝脏组织作病理切片观察。结果动物模型经持续45min缺血及90min再灌注后,肝功能明显受损,抗氧化酶活力显著下降,肝组织大片坏死;缺血后处理组和阿托伐他汀钙组能明显改善肝IR损伤程度,升高SOD活性,降低MDA、MPO和体内NO的水平,明显减轻肝窦上皮和血管内皮的损伤,减轻肝细胞损伤和炎性细胞的浸润。结论缺血后处理组和阿托伐他汀钙预处理组对大鼠肝缺血再灌注损伤有保护作用且效果相当,而药物处理更简便。其可能的机制为提高机体抗氧化能力、清除氧自由基和抗炎作用有关。     

克霉唑抗大鼠肝缺血再灌注损伤机制研究

目的研究孕烷X受体(pregnane X receptor,PXR)介导克霉唑抗大鼠肝缺血再灌注损伤作用及其机制。方法 SD大鼠随机分成4组,分别为假手术组、缺血再灌注组、克霉唑低剂量组和克霉唑高剂量组。以谷丙转氨酶(ALT)、谷草转氨酶(AST)、乳酸脱氢酶(LDH)、超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活性、丙二醛(MDA)含量及热休克蛋白70(HSP70)蛋白表达等为观察指标,用终浓度分别为25 mg/kg和50 mg/kg的克霉唑预处理大鼠5 d,5 h后观察其对肝缺血再灌注损伤的作用。结果 PXR特异性强诱导剂克霉唑,与假手术组比,能明显诱导CYP3A1基因表达,表现为ALT、AST和LDH显著降低(P<0.05),且呈剂量依赖性,SOD和GSH-Px活性分别升高,MDA显著降低,对抗氧自由基ROS损伤,上调HSP70表达(P<0.05),表现出强大的抗缺血再灌注损伤作用。结论克霉唑预具有较好抗肝缺血再灌注损伤的保护作用,其机制可能在PXR介导下,拮抗ROS损伤及内源性保护蛋白HSP70表达上调有关。     

维生素E在大鼠肝脏缺血再灌注损伤中的作用

目的探讨维生素E在肝组织缺血再灌注(I/R)损伤的保护机制及对缺血预处理(IP)的影响。方法采用大鼠原位半肝缺血再灌注和缺血预处理模型,缺血前通过灌胃给予维生素E(250mg/kg),分析血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、乳酸脱氢酶(LDH)、全血还原型谷胱甘肽(GSH)、肝组织脂质过氧化物(LPO)、超氧化物歧化酶(SOD)含量及肝组织病理改变等各项指标。结果I/R导致明显的肝损伤,IP减轻肝I/R损伤,维生素E能减轻肝组织缺血再灌注损伤,但可以部分抵消IP的保护作用。结论维生素E能减轻肝组织缺血再灌注损伤,其作用是通过减少氧自由基产生而实现的。IP对鼠肝I/R有明显的保护作用,IP期间产生的一定量的自由基,对随后的I/R的保护作用具有重要意义。维生素E导致氧自由基减少是肝IP保护作用的不利因素。     

高压氧预处理对大鼠肝脏缺血再灌注损伤的影响

目的探讨高压氧预处理对大鼠肝脏缺血再灌注损伤的影响。方法 40只雄性SD大鼠随机分为4组,假手术组(SO组);缺血再灌注组(IR组);高压氧预处理1组(HBO1组);高压氧预处理2组(HBO2组),每组10只。测定4组大鼠经处理后血清丙氨酸氨基转移酶(ALT)和天冬酸氨基转移酶(AST)以及各组大鼠经处理后肝脏组织学变化。结果 HBO2组及IR组ALT、AST水平明显高于SO组(P<0.05);HBO2组ALT、AST水平高于IR组(P<0.05);与HBO1组比较,HBO2组及IR组ALT、AST浓度差异均有统计学意义(P<0.05);HBO1组ALT、AST水平虽有上升,但与SO组比较差异无统计学意义(P>0.05)。HBO1组肝脏组织、小叶及汇管区结构清晰,可见肝细胞轻度水肿及瘀血;IR组肝小叶及汇管区可见轻度炎细胞浸润,片状肝细胞水肿,少数明显内空泡样变,肝组织瘀血,肝细胞坏死轻微;HBO2组肝脏小叶结构存在,肝小叶及汇管区可见大量炎细胞浸润,肝细胞坏死严重,HBO2组肝细胞水肿、坏死范围大于IR组。结论适量的高压氧预处理对肝脏缺血再灌注损伤有保护作用,而过量高压氧预处理,5d加重大鼠肝脏缺血再灌注损伤。     

一氧化氮对大鼠肝脏缺血再灌注致损伤的保护作用

目的：探讨一氧化氮在大鼠肝脏缺血-再灌注致损伤中的作用机制。方法：采用动物分组对照实验．研究了L-精氨酸(NO供体)对大鼠肝缺血再灌注损伤的影响，测量不同状态下动物血清中ALT、AST值，以及肝组织中谷胱甘肽过氧化物酶(GSH-Px)活力、丙二醛(MDA)浓度的变化。结果：一氧化氮明显减少肝组织中丙二醛含量和血清中ALT、AST含量以及增加肝组织中谷胱甘肽过氧化物酶活力。结论：一氧化氮对肝脏缺血再灌注损伤有保护作用，本实验为一氧化氮在肝缺血再灌注损伤的临床治疗提供实验基础。     

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.

---

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.     

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.     

Pharmacological treatment of COVID-19: an opinion paper

The precocity and efficacy of the vaccines developed so far against COVID-19 has been the most significant and saving advance against the pandemic. The development of vaccines has not prevented, during the whole period of the pandemic, the constant search for therapeutic medicines, both among existing drugs with different indications and in the development of new drugs. The Scientific Committee of the COVID-19 of the Illustrious College of Physicians of Madrid wanted to offer an early, simplified and critical approach to these new drugs, to new developments in immunotherapy and to what has been learned from the immune response modulators already known and which have proven effective against the virus, in order to help understand the current situation.     

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.