一氧化氮诱导PC12细胞凋亡及人参皂苷Rg1的保护作用

目的　探讨一氧化氮诱导PC12细胞凋亡及人参皂苷Rg1保护作用的可能机制。 方法　DNA凝胶电泳观察DNA的断裂情况 ,流式细胞仪检测线粒体跨膜电位 ,West ernblotting检测胞浆细胞色素C和活化型半胱氨酸蛋白水解酶caspase 3P2 0 水平。结果　一氧化氮供体SNAP(5 0 0μmol·L-1)可诱导PC12细胞凋亡 ,细胞线粒体跨膜电位明显下降、胞浆细胞色素C水平增加及caspase 3得到激活 ;预先经过 5 0、10和 2 0 μmol·L-1等浓度人参皂苷Rg1处理后 ,SNAP诱导的PC12细胞凋亡明显减少 ,同时明显减弱SNAP对细胞线粒体跨膜电位、胞浆细胞色素C水平及cas pase 3激活的影响。 结论　人参皂苷Rg1可抑制一氧化氮诱导PC12细胞凋亡 ,其作用机制可能与其稳定细胞线粒体跨膜电位、减少线粒体细胞色素C向胞浆释放及抑制cas pase 3的激活有关     

芍药苷对6羟基多巴胺致PC12细胞损伤的保护作用

目的:探讨芍药苷对6羟基多巴胺(6-OHDA)致大鼠肾上腺嗜铬细胞瘤细胞(PC12)的细胞损伤保护作用及其可能机制.方法:体外培养PC12细胞,用6-OHDA建立细胞损伤模型.MTT和乳酸脱氢酶(LDH)活性测定存活率;RT-PCR检测Bcl-2、Bax的mRNA表达,Hochest33342/PI双染检测细胞凋亡率.结果:25、50、100 μmol·L-1芍药苷可显著减少6-OHDA诱导的PC12细胞凋亡,降低LDH漏出率,增加Bcl-2 mRNA和减少Bax mRNA表达.结论:芍药苷可显著减少6-OHDA诱导的PC12细胞凋亡,其作用机制可能与调节Bax、Bcl-2表达有关.     

贯叶连翘对PC12细胞缺血性损伤的保护作用

目的:研究贯叶连翘对PC12细胞缺血性损伤的保护作用。方法:在离体培养的PC12细胞,用NaCN加缺糖造成拟缺血损伤模型,噻唑蓝(MTT)、LDH活力测定、细胞内肌酸激酶(CK)活力测定、流式细胞仪测定细胞凋亡率和线粒体跨膜电位。结果:在10-7~10-5mol.L-1范围内,贯叶连翘浓度依赖地增加MTT比色值,降低缺血性损伤所致培养介质内LDH的释放,增加细胞内CK活力。贯叶连翘还可剂量相关性地降低PC12细胞的凋亡百分率和稳定细胞线粒体跨膜电位。结论:贯叶连翘对PC12细胞缺血性损伤具有保护作用,其机制可能与增加细胞内CK活力和稳定细胞线粒体跨膜电位而抑制缺血性损伤诱导的PC12细胞的凋亡有关。     

甘草次酸对谷氨酸所致PC12细胞损伤的保护作用及其机理

目的 考察甘草次酸对谷氨酸诱导的PC12细胞损伤的保护作用及作用机制.方法 使用20 mmol·L-1谷氨酸处理大鼠嗜铬细胞瘤细胞株(PC12),构建细胞凋亡模型.采用药物预处理给药方法,MTT法测定细胞存活率,Fluo-4 AM染色测定胞内钙离子浓度,JC-1染色测定线粒体跨膜电位变化,western blot测定Bcl-2和Bcl-X1蛋白表达.结果 甘草次酸可明显提高谷氨酸诱导的PC12细胞的还原能力,抑制细胞LDH的释放,提高细胞存活率;抑制兴奋性谷氨酸所引起的细胞内钙离子内流;还原谷氨酸引起的线粒体跨膜电位的减弱,增加Bcl-2和Bcl-X1蛋白的表达量.结论 甘草次酸可通过线粒体依赖途径有效抑制谷氨酸诱导的PC12细胞凋亡.     

α-硫辛酸注射液对过氧化氢致PC12细胞损伤的保护作用

目的 研究α-硫辛酸注射液(抗氧化剂)对H2O2致PC12细胞损伤的保护作用.方法 600 μmol·L-1H2O2与细胞共同孵育4 h,建立PC12细胞氧化应激损伤模型,用MTT法,测定细胞生长抑制率;培养介质中的LDH测定,用紫外分光光度法,用流式细胞术测定细胞凋亡率和线粒体膜电位.结果 与模型组相比,3个剂量(10,1 μmol·L-1)α-硫辛酸注射液能提高H2O2损伤的PC12细胞的存活率,减少LDH的漏出,降低细胞凋亡率,抑制线粒体膜电位的下降(P＜0.05,P＜0.01).结论 α-硫辛酸注射液对H2O2致PC12细胞损伤模型具有较好的保护作用.     

山楂叶总黄酮对H_2O_2诱导PC12细胞凋亡的保护作用

目的探讨山楂叶总黄酮(FMCL)对H2O2诱导的PC12细胞凋亡的保护作用及机制。方法用H2O2刺激PC12细胞使其发生凋亡,MTT法检测PC12细胞活性,倒置显微镜观察细胞生长状况和形态变化,琼脂糖凝胶电泳观察DNA梯状图谱,流式细胞仪检测PC12细胞亚二倍体比率及线粒体膜电位的变化。结果与模型组比较FMCL 100、30mg.L-1两组PC12细胞活性增强,贴壁生长数量增多,而圆缩脱落者减少,未见典型DNA梯状图谱,凋亡比率下降,线粒体膜电位回升,且在一定范围内存在剂量依赖关系。结论山楂叶总黄酮可抑制H2O2诱导的PC12细胞凋亡,其机制可能与抑制线粒体途径的细胞凋亡有关。     

大黄素体外抑制膀胱癌BIU-87细胞增殖的实验研究

目的探讨大黄素对人膀胱癌BIU-87细胞增殖的抑制作用及其可能机制。方法采用倒置显微镜观察细胞生长,DAPI染色观察凋亡细胞;CCK-8法检测不同浓度的大黄素作用不同时间对BIU-87细胞增殖的抑制作用;JC-1检测线粒体跨膜电位并衡量线粒体去极化的比例以及caspase-9活性检测探讨大黄素抑制BIU-87细胞增殖的作用机制。结果不同浓度(10,20,40,60,80μmol·L-1)的大黄素均可抑制膀胱癌BIU-87细胞的增殖,且抑制率呈浓度依赖和时间依赖关系;大黄素作用BIU-87细胞24、48、72小时后半数抑制浓度(IC50)分别为:(46.27±2.32)μmol·L-1、(34.79±1.75)μmol·L-1、(25.58±1.24)μmol·L-1。随大黄素作用时间以及剂量的增加,BIU-87细胞凋亡率增加,线粒体跨膜电位逐渐下降,作用12小时后caspase-9活性随药物浓度增加而增加。结论大黄素能有效地抑制人膀胱癌BIU-87细胞的增殖,其可能机制为通过线粒体途径诱导细胞凋亡。     

阿魏酸钠对硝普钠诱导的原代培养海马神经元凋亡的保护作用

目的:探讨阿魏酸钠(sodium ferulate,SF)对NO供体硝普钠(SNP)引起的大鼠海马神经元凋亡保护作用的可能机制.方法:原代培养的大鼠海马神经元,经终浓度为10～160 μmol·L-1的SF预处理6 h后,用50 μmol·L-1的SNP处理24 h,采用MTT法检测细胞存活率,Hochest 33258荧光染色及DNA琼脂糖凝胶电泳分析等方法检测凋亡,Western blot及RT-PCR检测bcl-2基因表达.结果:不同浓度SF(10～160μmol·L-1)预处理6 h可显著提高神经元的存活率,减少SNP引起的核固缩、凝聚和碎裂现象;DNA凝胶电泳图谱未见典型的"梯子状"改变;增加bcl-2 mRNA及蛋白的表达.结论:SF对NO供体SNP诱导的海马神经元凋亡具有明显的保护作用,其机制可能与增加抗凋亡基因bcl-2表达有关.     

灯盏乙素对PC12细胞拟缺血性损伤的保护作用研究

目的:研究灯盏乙素对PC12细胞拟缺血性损伤的保护作用,并探讨其作用机制。方法:用连二亚硫酸钠(Na2S2O4)加缺糖复制PC12细胞拟缺血模型。以MTT法检测细胞存活率并进行乳酸脱氢酶(LDH)活力测定;应用Hoechst33342染色法证明凋亡细胞的存在;应用流式细胞仪检测凋亡细胞的比率及线粒体膜电位的变化;应用激光共聚焦显微镜观察灯盏乙素作用下细胞内钙离子(Ca2+)浓度的变化。结果:在10-7～10-5mol.L-1范围内,灯盏乙素可增加损伤细胞的存活率,降低缺血性损伤所致培养介质内LDH的释放,具有浓度依赖性;灯盏乙素还可降低PC12拟缺血性损伤细胞的凋亡百分率和稳定细胞线粒体跨膜电位,降低细胞内Ca2+浓度,具有浓度依赖性。结论:灯盏乙素对PC12细胞拟缺血性损伤有显著保护作用,其机制可能与稳定细胞线粒体跨膜电位与抑制Ca2+内流有关。     

瓜子金皂苷己对MPP~+诱导PC12细胞凋亡的保护作用

目的观察瓜子金皂苷己(polygalasaponin F,PS-F)对1-甲基-4-苯基-吡啶离子(1-methyl-4-phenylpyridinium,MPP+)诱导的PC12细胞损伤的影响,并且探讨其作用机制。方法 MTT法检测细胞存活率,Annexin V/PI染色流式细胞术检测PC12细胞凋亡,JC-1染色倒置显微镜检测细胞线粒体膜电位(mitochondrial membrane potential,MMP),Western blot检测Caspase-3蛋白的水平。结果 500μmol.L-1MPP+作用PC12细胞48 h,能明显抑制细胞生长(P<0.01),诱导细胞发生凋亡,同时降低MMP,增加活性Caspase-3的蛋白水平。同时给予不同浓度PS-F处理,PC12细胞存活率增加(P<0.01);凋亡细胞量减少;MMP增高;活性Caspase-3蛋白水平降低(P<0.01)。结论 PS-F能抑制MPP+诱导的PC12细胞的凋亡,其作用机制可能与维持线粒体正常膜电位,稳定线粒体功能,降低活性Caspase-3蛋白水平有关。     

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.