二氢槲皮素预处理对心肌缺血/再灌注损伤抗氧化作用的影响

目的探讨二氢槲皮素(dihydroquercetin,DDQ)对大鼠离体心脏缺血/再灌注损伤抗氧化作用的影响。方法SD大鼠40只,随机分为正常组、模型组、二氢槲皮素低剂量组(5 mg·L~(-1))、二氢槲皮素高剂量组(10 mg·L~(-1))4组。使用Langendorff逆行恒压灌流方式建立离体大鼠心脏I/R模型。观察I/R期间DDQ对左心室舒张压、左心室收缩压、室内压最大上升速率、室内压最大下降速率和心率的影响。乳酸脱氢酶(LDH)水平和血清肌酸激酶(CK)的含量均采用酶联免疫吸附法进行分析,TTC染色法评价心肌梗死程度,测定心肌组织中超氧化物歧化酶(SOD)、还原型谷胱甘肽/氧化型谷胱甘肽(GSH/GSSG)和丙二醛(MDA)含量,HE染色观察心肌组织学结构的病变。结果与模型组比,DDQ预处理组能够明显改善血流动力学的各项指标;DDQ预处理组可使心肌组织中的SOD和GSH/GSSG的含量明显增加;CK,LDH和MDA的含量明显降低,同时降低心肌梗死程度,减轻心肌组织学病变。结论 DDQ对离体大鼠缺血/再灌注损伤具有明显的保护作用,此保护作用可能与DDQ提高氧自由基清除能力,减少氧自由基产生,降低脂质过氧化损伤的作用机制有关。     

硫化氢对离体大鼠心脏缺血/再灌注损伤的影响及机制初探

目的观察内源性CSE/H2S通路的改变以及给予H2S供体对缺血/再灌注心脏的影响,探讨该通路与心脏缺血/再灌注损伤的关系及作用机制。方法采用Langendorff离体灌流装置、通过停灌30min/复灌30min方式造成Wistar大鼠心肌缺血/再灌注损伤模型;采用外源性NaHS(40μmol.L-1)分别在停灌30min前(SIR)与停灌30min后处理(IRS)对缺血/再灌注心脏的影响。记录心脏收缩期左心室内压上升的最大变化速率(+dp/dtmax)、舒张期左心室内压下降的最大变化速率(-dp/dtmax)及左室内压差(LVP=左室收缩压-左室舒张压)。采用比色法检测灌流液中乳酸脱氢酶(LDH)、心肌MDA及SOD;采用比色法检测心肌胱硫醚-γ-裂解酶(CSE)活性;采用RT-PCR方法测定心肌组织CSEmRNA表达。结果与缺血/再灌注组(I/R)30min相比,SIR组及IRS组±dp/dtmax、LVP均增高,LDH降低;I/R组MDA水平高于对照组(CON)、SIR组及IRS组(P<0.05,P<0.01);IR组SOD活性低于SIR组及IRS组(P<0.05),但与CON组差别无显著性;I/R组大鼠心肌CSE活性低于CON组(P<0.05);而大鼠心肌CSEmRNA的表达与CON组差异无显著性。结论在缺血前后给予外源性NaHS均可改善因再灌注损伤引起的心肌收缩及舒张功能障碍;其作用机制可能是通过提高心肌SOD活性,增加氧自由基清除而拮抗缺血/再灌注引起的心功能及细胞膜损伤;心肌缺血/再灌注时内源性CSE活性抑制可能与心功能障碍及细胞损伤有关。     

碱性成纤维细胞生长因子对大鼠心肌保护机制研究

目的　在大鼠离体心肌缺血 -再灌注 (I/R)损伤模型上 ,观察碱性成纤维细胞生长因子 (bFGF)对心肌金属硫蛋白的影响 ,探讨bFGF心肌保护作用的可能机制。方法　复制大鼠离体心脏I/R损伤模型。预先2 4h应用bFGF ,以生理多导仪测定±dp/dtmax .[Cd10 9] 血红素饱和法测定心肌MT含量 ,硫代巴比妥法测心肌丙二醛 (MDA)含量 ,以自动生化分析仪测灌流液乳酸脱氢酶 (LDH)活性。结果　bFGF可诱导心肌MT生成 ,bFGF组心肌MT含量升高 ,MDA含量大于I/R组 ,灌流液乳酸脱氢酶 (LDH)及蛋白漏出明显减少 ,同时心功能明显改善。结论　MT参与了bFGF对大鼠离体心肌缺血 -再灌注 (I/R)损伤心肌保护作用。     

哌芳安他预处理对大鼠心肌缺血再灌注损伤的保护作用

目的　研究新化合物哌芳安他对大鼠离体工作心脏心功能的影响及其对离体工作心脏缺血再灌注的保护作用。方法　在大鼠离体工作心脏模型上观察低、中、高三个剂量组哌芳安他(浓度分别为10-6 mol·L-1、10-5 mol·L-1、10-4 mol·L-1 )对各项心功能参数(HR、LVSP、+dp/dtmax、LVEDP、-dp/dtmax及Vmp)的影响,在大鼠离体缺血再灌注心脏模型上观察低中高三个剂量组哌芳安他预处理后,对再灌注后各心功能指标的影响,并检测再灌注后心肌组织中MDA、LA含量及SOD活性。结果　在离体工作大鼠工作心脏模型上,高剂量哌芳安他可以改善+dp/dtmax及-dp/dtmax,预处理后,三个剂量组均对缺血再灌注后离体工作大鼠工作心脏LVSP有改善作用,中、低剂量组均表现出了改善Vmp及+dp/dtmax和LVEDP的作用(P<0 05)或趋势。同时,哌芳安他可以升高心肌组织SOD活性,并可降低心肌组织中MDA水平,但对LA水平无影响。结论　哌芳安他可以轻度改善大鼠离体工作心脏的舒缩功能,预处理后,能明显改善缺血再灌注后大鼠离体工作心脏的功能,并可以显著改善心肌组织的抗氧化能力,从而表现出明显的抗缺血再灌注损伤作用。     

丹参川芎嗪对离体大鼠心肌缺血/再灌注损伤的保护作用

目的通过对大鼠离体心脏灌流不同剂量受试药丹参川芎嗪(SLI),探讨受试药对离体心肌缺血/再灌注(I/R)损伤的保护作用。方法采用Langendorff离体心脏恒压灌流系统建立心肌缺血/再灌注模型。SD大鼠随机分为五组(n=11),包括空白对照组(Control)、模型组(Model)、SLI高剂量组(High)、中剂量组(Middle)、低剂量组(Low)。将分离后的大鼠心脏连接在Langendorff离体灌流仪器上,先平衡灌注20min,再全心停灌20min,然后复灌60min;空白对照组连续灌流100min。采用labchart生物信号采集仪器记录观察各受试药物组对心功能的影响。结果与模型组相比,SLI各剂量组I/R的相关指标LVDP、+dp/dtmax明显升高(P <0.05),冠脉流出液中LDH、CK、MDA含量显著降低(P <0.05),而SOD水平则明显升高。HE染色结果显示,模型组心肌细胞着色不均、纤维排列紊乱、心肌形态不完整,心肌纤维间可见中性粒细胞浸润,部分心肌细胞坏死,而SLI各剂量组均不同程度地改善了这一改变。结论 SLI能减轻离体心肌缺血/再灌注诱导的冠脉损伤,对心脏功能恢复具有促进作用,其机制可能与改善心肌舒缩功能,清除氧自由基有关。     

三七茎叶皂苷对大鼠离体心脏缺血/再灌注损伤的保护作用

目的研究三七茎叶皂苷对大鼠离体心脏缺血/再灌注(I/R)损伤的作用及其作用机制。方法 SD大鼠36只,随机分为6组(n=6),分别是空白对照组、模型组、阳性给药组(地奥心血康70 mg.kg-1)、三七茎叶皂苷低、中、高剂量组(20、40、80 mg.kg-1)。阳性给药组和三七茎叶皂苷给药组大鼠每日灌胃给药1次,连续给药7 d,空白对照组和模型组同时给予同体积生理盐水。末次给药60 min后,分离心脏置于Langendorff离体灌流装置上,平衡15 min后,全心停灌25 min,再灌注60 min,造成心肌缺血/再灌注损伤模型。于大鼠左心房插入水囊导管,记录三七茎叶皂苷对血流动力学指标的影响,测定再灌注60 min后灌流液中乳酸脱氢酶(LDH),肌酸激酶(CK)的活性及心肌组织中超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)、LDH、CK活性及丙二醛(MDA)的含量。HE染色观察组织形态学改变。结果三七茎叶皂苷不同剂量组(20、40、80 mg.L-1),可明显改善缺血/再灌注所致大鼠的心功能损伤,减少灌流液中LDH、CK释放和组织中MDA的产生,增加SOD、GSH-Px的活性。HE染色结果显示,阳性给药组与三七茎叶皂苷高、中、低剂量组均不同程度的减轻了I/R造成的心肌损伤。结论三七茎叶皂苷对心肌缺血/再灌注损伤具有保护作用,其机制可能与改善心肌舒缩功能,清除氧自由基,减少脂质过氧化反应有关。     

大豆异黄酮预防离体大鼠心肌缺血再灌注损伤

目的:观察大豆异黄酮(SI)预处理对离体大鼠心肌缺血再灌注损伤的影响。方法:应用Langendorff灌注大鼠离体心脏,停灌/复灌方式制备缺血再灌注模型。SD雄性大鼠40只,随机分为正常对照组、缺血再灌注组(I/R)、低剂量SI组(L-SI)、中剂量SI组(M-SI)、高剂量SI组(H-SI),L-SI、M-SI、H-SI组分别予SI 30、60、120mg.kg-1.d-1灌胃,第15天末采集心脏收缩期左心室内压上升的最大变化速率(+LVdp/dtmax)、舒张期左心室内压下降的最大变化速率(-LVdp/dtmax)及左室发展压(LVDP)、左心室舒张末压(LVEDP)及心率与发展压的乘积(RPP)并分析;电镜观察心肌细胞超微结构改变。结果:与正常对照组比较,I/R组LVEDP明显升高(P<0.01);LVDP,+dp/dtmax,-dp/dtmax,RPP均明显降低(P<0.05,P<0.01)。与I/R组比较,M-SI组LVEDP明显降低(P<0.01),RPP明显升高(P<0.05)。与I/R组比较,H-SI组LVDP、+dp/dtmax、-dp/dtmax均明显升高(P<0.05,P<0.01)。I/R组中,心肌纤维断裂,线粒体肿胀,嵴破坏消失,此变化在M-SI、H-SI预处理组中明显减轻。结论:中、高剂量SI对离体缺血再灌注大鼠受损伤的心肌有保护作用。     

天山花楸叶总黄酮对大鼠心肌缺血/再灌注损伤的保护作用

目的观察天山花楸叶总黄酮对大鼠心肌缺血/再灌注(I/R)损伤的保护作用,探讨其作用机制。方法采用改良的Langendorff逆行恒压灌流方法,建立大鼠离体心脏I/R损伤模型,观察天山花楸叶总黄酮(4.0、6.0mg·L-1)对心脏I/R损伤后心功能、心肌组织中超氧岐化酶(SOD)活性和丙二醛(MDA)含量变化的影响。利用DPPH、羟自由基、超氧阴离子、脂质过氧化反应体系,检测了天山花楸叶总黄酮(6.25、12.5、25、50、100mg·L-1)体外抗氧化能力。结果天山花楸叶总黄酮(6.0mg·L-1)可明显改善离体心脏I/R损伤后左心室发展压(LVDP)和左室压力升高或降低最大速率(±dp/dtmax),明显增加冠脉流量;天山花楸叶总黄酮(6.0mg·L-1)处理后I/R损伤心肌组织中SOD活性升高,MDA含量减少。天山花楸叶总黄酮(6.25～100mg.L-1)可浓度依赖性地清除DPPH自由基、羟自由基和超氧阴离子自由基,并抑制脂质过氧化反应。结论天山花楸叶总黄酮对心肌缺血/再灌注损伤具有明显保护作用,与其具有较强的抗氧化活性有关。     

辛伐他汀后处理对离体大鼠心肌缺血再灌注损伤的影响及机制

目的观察辛伐他汀对离体大鼠心肌缺血再灌注损伤(I/R)细胞凋亡的影响,初步探讨其机制。方法采用Langendorff离体心脏灌流模型,32只SD大鼠随机等分为4组:对照组、I/R组、辛伐他汀后处理组、辛伐他汀+L-硝基精氨酸甲酯(L-NAME)组。进行再灌注心律失常分析;冠脉流出液中肌酸激酶(CK)、乳酸脱氢酶(LDH)及NO含量测定;Western印迹法检测心肌组织p-Akt信号蛋白的表达;Annexin-V-FITC/PI法检测细胞凋亡指数(AI)。结果与I/R组比较,辛伐他汀后处理组心律失常发生率下降、CK和LDH含量降低、p-Akt蛋白表达及NO含量增加、细胞AI降低(P<0.01)。辛伐他汀+L-NAME组较辛伐他汀后处理组心律失常发生率升高、CK和LDH含量增加、p-Akt蛋白表达及NO含量降低、细胞AI增高(P<0.01);与I/R组比较,无显著差异(P>0.05)。结论辛伐他汀后处理能减轻大鼠心肌I/R损伤,减少心肌细胞凋亡,其作用机制可能与PI3K-Akt通路活化有关。     

蝙蝠葛酚性碱对心肌缺血及缺血再灌注损伤的保护作用

目的研究蝙蝠葛酚性碱(PAMD)对心肌缺血及缺血再灌注损伤的作用。方法用大鼠皮下注射异丙肾上腺素85 mg.kg-1造成心肌缺血模型,于造模前30 min灌胃给予生理盐水、PAMD(7.5,15或30 mg.kg-1)、地尔硫10 mg.kg-1或地奥心血康150 mg.kg-1,测定心肌缺血后乳酸脱氢酶(LDH)、肌酸激酶(CK)、超氧化物歧化酶(SOD)和丙二醛(MDA)含量及病理学改变。离体大鼠心脏缺血30 min再灌注40 min,分别给予PAMD(1,10或100 mg.L-1)或地奥心血康100 mg.kg-1,测定心肌缺血再灌注后左室收缩压(LVSP)、左室舒张末压(LVEDP)和左室压最大变化速率(±dp/dtmax)、冠脉流量,测定心肌SOD活性和MDA含量。结果 PAMD显著降低缺血所致的LDH、CK和MDA升高,提高SOD活性,减轻心肌病理损伤。PAMD促进缺血再灌注末LVSP、LVEDP和±dp/dtmax等恢复,增加冠脉流量和SOD活性并降低MDA含量。结论 PAMD对心肌缺血及缺血再灌注损伤有保护作用,其机制可能与其抗氧化及改善心肌代谢有关。     

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.     

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.     

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.