白藜芦醇对原代培养大鼠脑皮质神经元氧糖缺失损伤的保护

目的 观察白藜芦醇(Res)对原代培养大鼠脑皮质神经元氧糖缺失损伤的保护作用.方法 将新生大鼠脑皮质神经元原代培养至第10天,以低糖结合物理性缺氧诱导缺氧缺糖(OGD)模型,并于造模 2 h后复氧复糖(RP),尼莫地平(Nim 1.0 μmol · L-1)为阳性对照,观察Res对OGD和OGD/RP的噻唑蓝(MTT)液比色吸光度和乳酸脱氢酶(LDH)释放百分率的影响,在光镜和电镜下观察神经元的形态变化.结果 Res的增加对神经元OGD 1、2、4 h和OGD 2 h/RP 3、12、24 hMTT液的吸光度有显著性差异,可减少其LDH的释放,减轻神经元形态的损伤.结论 Res对原代培养大鼠脑皮质神经元氧糖缺失损伤具有保护作用.     

杨梅叶总黄酮对培养大鼠皮质神经元缺糖缺氧损伤的影响

目的探讨杨梅叶总黄酮对原代培养大鼠皮质神经元缺糖缺氧损伤的影响。方法采用原代培养的大鼠皮质神经元,随机分为正常组、神经元缺糖缺氧(oxygen-glucose deprivation,OGD)模型组和杨梅叶总黄酮高、中、低质量浓度(100、10、1 mg.L-1)给药组,MTT法观察神经元的存活率,比色法检测细胞培养液中乳酸脱氢酶(lactate dehydrogenase,LDH)释放量、过氧化氢(hydrogen perox-ide,H2O2)含量,并检测细胞内超氧化物歧化酶(superoxide dismutase,SOD)活性及丙二醛(malondi-aldehyde,MDA)含量。结果杨梅叶总黄酮可显著提高受损伤神经元的存活率和皮质神经元细胞内SOD活性,降低神经元细胞LDH的释放、细胞内MDA含量和细胞培养液中H2O2含量。结论杨梅叶总黄酮对缺糖缺氧所致皮质神经元损伤具有明显的保护作用。     

盐酸法舒地尔对体外培养星形胶质细胞氧糖剥夺损伤的保护作用

目的研究盐酸法舒地尔(FH)对大鼠皮质星形胶质细胞氧糖剥夺损伤(OGD)的保护作用。方法传代培养的大鼠皮质星形胶质细胞与无糖Na2S2O42 mmol·L-1孵育4 h,制备OGD模型。FH 5和10μmol·L-1在OGD前2 h加入。采用噻唑蓝(MTT)法检测细胞存活;比色法检测乳酸脱氢酶(LDH);乙炔基脱氧尿苷(Ed U)掺入法检测星形胶质细胞DNA合成;Hoechst染色和丫啶橙(AO)/溴化乙啶(EB)荧光双染观察细胞凋亡;2,7-二氯氢化荧光素(DHCF-DA)荧光染色和硝基四氮唑蓝(NBT)还原实验检测细胞内活性氧(ROS)水平。结果与正常对照组比较,OGD模型组星形胶质细胞存活率为(24±6)%,下降了4倍(P<0.01);OGD模型组LDH释放量显著升高至(366±7)U·L-1(P<0.01)。加入FH 5和10μmol·L-1的预处理组,细胞存活率分别上升至(42±5)%和(43±5)%,LDH释放分别下降至290±18和(268±20)U·L-1(P<0.01),细胞Ed U阳性率由OGD模型组的(47±6)%,分别下降到(35±6)%和(29±5)%(P<0.01)。Hoechst染色及AO/EB双染实验结显示,FH能显著减少OGD损伤后细胞的凋亡及坏死,使晚期凋亡细胞比例减少(P<0.05);DCFH-DA荧光和NBT还原实验显示,FH降低OGD损伤后ROS水平,且FH10μmol·L-1的预处理组降低的幅度比5μmol·L-1的预处理组更明显,但两组差异无统计学意义。结论FH对传代培养的大鼠皮质星形胶质细胞OGD具有保护作用,其作用机制可能与降低细胞内ROS水平有关。     

17β雌二醇对氯胺酮所致神经元凋亡的影响

目的：研究17β雌二醇对氯胺酮所致原代培养皮质神经元凋亡的影响及其机制。方法原代培养皮质神经元,体外培养7 d,随机分为空白对照组（给予相同体积的DMSO）,雌二醇组（17β雌二醇终浓度为0.1μmol·L-1）,氯胺酮组（氯胺酮终浓度为100μmol·L-1）,氯胺酮＋雌二醇组（氯胺酮,17β雌二醇终浓度分别为100μmol·L-1,0.1μmol·L-1）。噻唑蓝（ MTT）法检测神经元存活率,Hoechest33258染色法检测皮质神经元凋亡,Western-blot 法测定cleaved-Caspase-3及Bcl-2蛋白表达。结果氯胺酮组神经元存活率（54.02±7.78）%,明显低于空白对照组;氯胺酮＋雌二醇组神经元存活率（88.09±6.54）%,明显高于氯胺酮组。神经元经Hoechest33258染色在荧光显微镜下观察,氯胺酮组神经元凋亡[凋亡率（49.50±4.34）%]较空白对照组明显增加,氯胺酮＋雌二醇组[凋亡率（15.74±3.40）%]较氯胺酮组神经元凋亡下降。氯胺酮组 cleaved-Caspase-3表达明显增加,Bcl-2明显下降,而氯胺酮＋雌二醇组较氯胺酮组cleaved-Caspase-3表达明显下降,Bcl-2表达明显升高。结论17β雌二醇通过抑制神经元凋亡对抗氯胺酮诱导的皮质神经元损伤,产生保护作用。     

右美托咪定在体外对原代海马神经元氧化应激损伤的影响

目的 探讨右美托咪定在体外减弱原代海马神经元的氧化应激损伤的机制.方法 将培养的原代海马神经元分为5组:空白对照组(C组)、损伤对照组(S组)、右美托咪定组(D组),D1,D2,D3组加入不同剂量的右美托咪定(0.001μmol/L、0.1μmol/L、10μmol/L).利用1 mmol/L的过氧化氢(H2O2)处理原代海马神经元1 h,制作神经元氧化应激损伤模型.按照以上分组情况加入右美托咪定,37℃、5％二氧化碳孵箱孵育6 h.通过测定细胞存活率和上清液中乳酸脱氢酶(LDH)的活性确定减轻海马神经元损伤的右美托咪定的适宜浓度.并检测细胞内丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性的变化.应用逆转录聚合酶链反应(RT-PCR)方法测量各组细胞外信号调节激酶(ERK)1/2和脑源性神经营养因子(BNDF)mRNA表达量.结果 右美托咪定组(0.001μmol/L、0.1μmol/L、10μmol/L)细胞存活率分别为(72.13±2.45)％、(89.34±2.56)％、(78.40±2.60)％,均高于损伤组的(51.04±2.12)％,差异有统计学意义(P<0.05);LDH活性显著低于损伤对照组;0.1μmol/L右美托咪定组对海马神经细胞氧化应激损伤的保护作用最好.0.1μmol/L右美托咪定组海马神经细胞培养上清液中MDA含量及细胞凋亡率显著低于损伤对照组,SOD活性显著高于损伤对照组.RT-PCR法检测结果提示0.1μmol/L右美托咪定组ERK1/2和BNDF mRNA表达量显著高于损伤对照组.结论 适宜剂量的右美托咪定对氧化应激损伤的海马神经元有一定的保护作用,其作用机制可能与其能够提升海马神经细胞的抗氧化能力,从而抑制海马神经元的凋亡有关,这种功能可能与ERK1/2和BNDF信号通路有关.     

乙酰胆碱介导的内皮超极化因子对海马神经元缺氧/再给氧损伤的保护作用

目的研究乙酰胆碱(acetylcholine,ACh)介导的大鼠大脑中动脉内皮释放的内皮超极化因子(endothelium-de-pendent hyperpolarizing factor,EDHF)对海马神经元缺氧/再给氧损伤的保护作用。方法用原代培养的大鼠海马神经元细胞建立缺氧/再给氧损伤模型,取大鼠大脑中动脉(mid-dle cerebral artery,MCA)血管段,PGI2和NO的阻断剂NG-ni-tro-L-argininemethyl ester(L-NAME)和indomethacin(Indo)预处理后,用ACh刺激血管内皮释放EDHF,用四甲基偶氮唑盐(MTT)染色吸光度和乳酸脱氢酶(LDH)活性作为细胞损伤指标,用激光共聚焦显微镜检测细胞内游离Ca2+浓度。结果与正常对照组相比,缺氧/再给氧损伤组细胞MTT染色吸光度明显降低,上清液中LDH活性和细胞内Ca2+浓度则明显升高。1μmol.L-1ACh合用含血管内皮的MCA血管段(MCA/Endo)或ACh+MCA/Endo+L-NAME+Indo均可抑制缺氧/再给氧致海马细胞MTT染色吸光度降低、培养上清液中LDH活性及细胞内Ca2+浓度的升高,但单用1μmol.L-1ACh或MCA/Endo却无上述抑制作用,合用1μmol.L-1ACh和去内皮MCA血管段(MCA/-Endo)也无明显抑制作用。K+在25~35μmol.L-1范围内,可明显减弱ACh+MCA/Endo+L-NAME+Indo对缺氧再给氧致海马神经细胞MTT染色吸光度降低、上清液LDH活性及细胞内Ca2+浓度升高的抑制作用,但Ba2+没有明显影响。结论假定的EDHF对原代培养的海马神经元缺氧/再给氧损伤具有保护作用,其机制可能与抑制缺氧/再给氧引起的钙超载有关。     

17β雌二醇对氯胺酮诱导皮层神经元凋亡的影响

目的研究17β雌二醇对氯胺酮诱导的原代培养皮层神经元凋亡的影响。方法原代培养大鼠皮层神经元,分别给予不同浓度的氯胺酮及17β雌二醇培养24 h,MTT法检测神经元的存活率,显微镜下观察神经元的形态变化,TUNEL法检测神经元调亡,Western blot法测定pAkt蛋白的表达。结果与对照组比较,氯胺酮能剂量依赖性降低神经元存活率。与氯胺酮组比较,17β雌二醇能剂量依赖性提高神经元的存活率。100μmol·L-1氯胺酮组显微镜下神经元数量减少,胞体立体感消失,细胞轮廓不清,神经元轴突断裂,TUNEL阳性神经元明显增加,pAkt表达明显降低。0.1μmol·L-117β雌二醇与100μmol·L-1氯胺酮共处理改善了氯胺酮引起的神经元损伤,TUNEL阳性神经元明显下降,pAkt表达增加。PI3K抑制剂LY294002拮抗了17β雌二醇的保护作用,TUNEL阳性神经元较0.1μmol·L-117β雌二醇与100μmol·L-1氯胺酮共处理组明显增加,pAkt表达明显下降。结论 17β雌二醇可以保护神经元免受氯胺酮导致的凋亡,其保护作用可能是通过激活PI3K-Akt信号通路实现的。     

褪黑素对谷氨酸所致大鼠神经细胞损伤及一氧化氮释放增加的影响

目的:研究褪黑素(melatonin;MT)对谷氨酸(L-glutamate;L-Glu)引起的神经细胞损伤及一氧化氮释放增加的影响.方法:取乳大鼠的神经细胞进行原代培养,加入谷氨酸造成神经元损伤模型;分别以四甲基偶氮唑蓝比色(MTT)法测定细胞存活率,Gress法测定一氧化氮的释放量,通过这两种指标考察MT对谷氨酸神经毒性的对抗作用.结果:谷氨酸500μmol·L-1造成神经细胞的MTT活性显著降低(P＜0.05),同时一氧化氮释放量非常显著的增加(P＜0.01);而MT(10-5,10-4 mol·L-1)可使MTT活性显著增强(P＜0.05,P＜0.01),同时亦明显抑制一氧化氮的释放(P＜0.05).结论:提示MT可通过抑制谷氨酸引起的一氧化氮释放增加对抗其神经毒性,保护神经细胞免受损伤.     

Aβ25-35对原代培养大鼠皮质神经元的损伤作用

目的 考察Aβ25-35对原代培养大鼠皮质神经元的损伤作用.方法 将原代培养的大鼠皮质神经元分为对照组、谷氨酸(glutamate,Glu)组及3个浓度的Aβ25-35组,每组各6孔.观察神经元的形态改变,并测定细胞存活率及培养液中乳酸脱氢酶(LDH)的活力值.结果 与对照组比较,Glu组可造成大鼠皮质神经元明显损伤,形态发生显著改变,细胞存活率为(53.1±5.5)%(P<0.01),并且培养液中LDH漏出显著增多,LDH的活力值为(39.9 4±2.9)U/g Prot (P<0.01);Aβ25-35三个剂量组神经元存活率均显著降低,分别为(69.3±5.9)%(P<0.01)、(52.7±3.0)%(P<0.01)和(33.2±1.8)%(P<0.01),Aβ25-35低、中剂量组培养液中LDH漏出未见明显改变,LDH活力值分别为(23.5±1.4)U/g Prot和(24.7±1.3)U/g Prot(P>0.05),Aβ25-35高剂量组培养液中LDH漏出显著升高,LDH活力值为(38.8±2.0)U/g Prot(P<0.01),与Glu组相当(P>0.05).结论 Aβ25-35能剂量依赖性地损伤皮质神经元,1 μmol/L Aβ25-35剂量组处理24 h后细胞存活率可降低50%左右,可用于Aβ25-35体外诱导阿尔茨海默病细胞模型的建立.     

二甲氨基乙氧基银杏内酯B甲磺酸盐对鼠脑微血管内皮细胞损伤的保护作用

目的:研究二甲氨基乙氧基银杏内酯B甲磺酸盐(RNGB)对谷氨酸致原代培养的大鼠脑微血管内皮细胞(RBMEC)损伤的保护作用.方法: 通过测定MTT、乳酸脱氢酶(LDH)的释放、丙二醛(MDA)含量和超氧化物歧化酶(SOD)活性,研究RNGB对谷氨酸(Glu)造成RBMEC损伤的保护作用.结果: 1 mmol·L-1的谷氨酸对原代培养的RBMEC产生明显的损伤.RNGB高浓度组(10 μmol·L-1)和中浓度组(3 μmol·L-1)明显对抗谷氨酸对RBMEC的损伤作用,抑制LDH的释放,增加SOD活力,降低MDA含量.结论: RNGB对谷氨酸所致原代培养的RBMEC损伤具有明显的保护作用.     

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.