As2O3诱导K562细胞凋亡过程中细胞表面电荷变化的研究

目的 :研究三氧化二砷 (As2 O3 )诱导K562 细胞凋亡时细胞表面电荷的变化 ,阐明As2 O3 诱导K562 细胞凋亡的可能机制 ,为As2 O3 在临床上的应用提供理论依据。方法 :应用细胞电泳仪检测As2 O3 诱导K562 细胞凋亡中细胞电泳率的变化。通过细胞增殖、活力检测 ,形态学观察 ,亚G1期细胞含量和DNA凝胶电泳等鉴定细胞凋亡。结果 :1.0～ 2 0 μmol·L-1As2 O3 作用于K562 细胞 ,在细胞形态、DNA凝胶电泳、FCM显示出典型的细胞凋亡特征之前 ,试验组细胞表面电荷已在 1.6h左右开始下降 ,6h内降低最明显 ,6h后虽有下降 ,但幅度明显减弱。与对照组比较 ,低于 1.0 μmol·L-1的As2 O3 对细胞表面电荷影响不大。结论 :细胞表面电荷的下降是K562 细胞凋亡的早期事件。细胞表面电荷的下降有一定的时间范围 ,超过此范围 ,细胞表面电荷下降趋向无限大。     

米非司酮联合三氧化二砷对K562/ADM的逆转作用及其机制

目的:探讨米非司酮(mifepristone)联合三氧化二砷(As2O3)对K562/ADM的逆转作用及机制研究。方法:不同浓度米非司酮、As2O3处理细胞72h,采用MTT法检测细胞增殖活性;流式细胞仪检测细胞凋亡、分光光度法检测细胞谷胱甘肽(GSH)含量。结果:10μmol.L-1的米非司酮对K562/ADM细胞无明显杀伤,可有效逆转K562/ADM细胞耐药性,此浓度米非司酮联合As2O3(2.0μmol.L-1)作用于K562/ADM细胞后,逆转倍数明显增高(P<0.01),GSH含量明显低于同浓度单用药组(P<0.05)。对细胞增殖抑制及其诱导凋亡的效果均明显高于同浓度单用药组(P<0.05)。结论:米非司酮联合As2O3逆转作用增强,机制可能与凋亡加强及GSH含量改变有关。     

三氧化二砷通过JNK信号通路诱导K562细胞凋亡

目的:探讨c-Jun氨基末端激酶(JNK)信号通路在三氧化二砷(As2O3)诱导K562细胞凋亡中的作用及机制。方法:体外培养K562细胞,用As2O3及特异性JNK抑制剂SP600125对K562细胞进行处理;倒置相差显微镜下观察细胞形态学变化;MTT法检测不同时间点细胞增殖抑制率;AnnexinV/PI染色结合流式细胞术检测细胞凋亡率;ELISA检测p-JNK蛋白表达的变化;流式细胞术检测突变型P53表达。结果:ELISA显示4μmol/LAs2O3作用48h后p-JNK蛋白表达增强,经SP600125预处理后,As2O3诱导的K562细胞p-JNK蛋白表达明显减弱(P<0.01),As2O3诱导的细胞增殖抑制率和细胞凋亡率均下降,与As2O3单作用组相比突变型P53表达增加(P<0.05)。结论:JNK信号转导通路在As2O3诱导K562细胞凋亡过程中发挥重要作用,是As2O3诱导K562细胞凋亡的主要途径之一。     

木犀草素对K562细胞caspase-3活化的影响

目的:探讨木犀草素对K562细胞增殖和凋亡的影响.方法:采用MTT法检测K562细胞的增殖,流式细胞术和Hoechst33258/PI荧光染色分析K562细胞的凋亡,比色法测定caspase-3的相对活性,半定量RT-PCR检测caspase-3 mRNA水平的改变,Western-blot分析caspase-3酶原的变化.结果:木犀草素处理细胞24 h后的IC50值为(104.6±13.5)μmol·L-1.浓度为10,20,40μmol·L-1木犀草素处理细胞24 h后均可诱导K562细胞发生凋亡,各处理组的细胞凋亡率均明显高于对照组(P＜0.01).随着浓度及时间的增加,各个木犀草素处理组K562细胞的caspase-3活性升高(P＜0.01),其作用具浓度及时间依赖性.而随着木犀草素浓度的增加,K562细胞中caspase-3的mRNA水平逐渐增加,caspase-3酶原的蛋白水平逐渐减少.结论:木犀草素可通过诱导K562细胞凋亡而抑制其增殖,其诱导K562细胞凋亡可能与激活caspase-3有关.     

木犀草素对K562细胞增殖与凋亡的影响及其机制

目的　探讨木犀草素对K562细胞增殖、凋亡的影响及其作用机制。方法　取对数生长期K562细胞分别加入0、10、25、50、100 μmol/L木犀草素培养24 h、48 h、72 h,采用CCK-8法检测细胞增殖抑制率;K562细胞分别加入0、25、50 μmol/L木犀草素培养48 h,采用流式细胞术检测细胞凋亡情况;K562细胞分别加入0、10、50、100 μmol/L木犀草素培养48 h,采用Westem blot检测B细胞淋巴瘤2蛋白（Bcl-2）、Bcl-2相关X蛋白（Bax）、多聚ADP核糖聚合酶（PARP）、Cleaved-PARP、半胱氨酸天冬氨酸蛋白水解酶3（Caspase3）、Cleaved-Caspase3、蛋白激酶B（AKT）、磷酸化AKT（p-AKT）、断裂点簇集区蛋白（BCR）、c-abl癌基因1（c-ABL）BCR-ABL蛋白表达。结果　CCK-8检测结果显示,随木犀草素浓度增加及作用时间的延长,K562细胞增殖抑制率均呈增长趋势（P＜0.05）。流式细胞仪检测结果显示,木犀草素0、25、50 μmol/L组K562细胞的凋亡率依次升高（分别为8.21%±0.55%、23.43%±1.50%和40.47%±2.97%）。Western blot结果显示,Bax、Cleaved-PARP、Cleaved-Caspase3表达水平随木犀草素浓度的增加而升高（P＜0.05）。木犀草素0、10、50 μmol/L组PARP蛋白表达水平依次升高（P＜0.05）,100 μmol/L组与50 μmol/L组差异无统计学意义。100 μmol/L组Caspase3、Bcl-2蛋白表达水平均低于其余组（P＜0.05）。50、100 μmol/L组p-AKT蛋白表达水平低于0、10 μmol/L组,100 μmol/L组低于50 μmol/L组。50 μmol/L组BCR-ABL融合蛋白表达水平高于0 μmol/L组,100 μmol/L组低于0、50 μmol/L组（P＜0.05）。结论　木犀草素可抑制K562细胞增殖,促进细胞凋亡,其机制可能与调控BCR-ABL蛋白表达及PI3K/AKT信号通路有关。     

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.     

新型苯胺嘧啶类化合物FABl07抗慢性髓性白血病的实验研究

目的:研究一种新型苯胺嘧啶类Bcr/Abl酪氨酸激酶抑制FAB107在体内外抗慢性髓性白血病(chronic myeloid leukemia,CML)的作用.方法:应用MTT法、流式细胞术及Western Blot法检测FAB107对K562细胞增殖、细胞凋亡以及Bcr/Abl蛋白磷酸化的影响.采用中空纤维模型观察FAB107在体内对K562细胞增殖的影响.结果:FAB107可以明显抑制K562和K562/G3.0细胞增殖,分别比伊马替尼强10和90倍;0.1μmol·L-1的FABl07比1μmol·L-1的伊马替尼具有更强的诱导K562和K562/G3.0细胞凋亡作用(P＜0.01);FAB107对K562和K562/G3.0细胞Bcr/Abl蛋白磷酸化的抑制作用均优于伊马替尼;FAB107在体内对K562及K562/G3.0细胞生长呈剂量依赖性的抑制作用,并且抑制强度强于等摩尔浓度的伊马替尼.结论:FAB107在体内外均具有较强的抗CML及伊马替尼耐药的CML的作用,且作用强于伊马替尼.     

二甲氧雌二醇诱导K562细胞凋亡作用及其凋亡机制

目的 研究二甲氧雌二醇(2-ME)对人白血病细胞K562细胞的增殖、凋亡作用及其机制.方法 分别以不同浓度的2-ME处理白血病细胞K562,应用Annexin Ⅴ和PI双染的流式细胞术检测K562细胞凋亡率,应用比色法测定caspase-3及caspase-9的活性变化,应用凝胶蛋白电泳迁移率分析法EMSA检测K562细胞核内NF-KB蛋白的结合活性变化情况.结果 2-ME浓度升高,细胞凋亡率明显增加(P＜0.01);当2-ME浓度为8μmol/L时,细胞凋亡率达64.3％;4μmol/L,2-ME作用K562细胞24h、36h、48 h后Caspase-3、Caspase-9活性明显升高.同时K562细胞核内NF-kappa B的DNA结合活性明显降低(P＜0.05).结论 2 -ME可显著抑制人白血病细胞K562增殖并诱导其凋亡,其机制与Caspase-3、-9活化及NF-kappa B蛋白信号通路有关.     

塞来昔布对人肺癌A549细胞株增殖抑制和凋亡诱导作用观察

目的 体外研究选择性环氧化酶2 (COX-2)抑制剂塞来昔布对人肺癌细胞株A549增殖和凋亡的影响,并探讨其可能的作用机制.方法 采用噻唑蓝(MTT比色法)观察不同浓度的塞来昔布对人肺癌细胞株A549的增殖抑制作用,TUNEL染色检测细胞凋亡,并用含半胱氨酸的门冬氨酸蛋白水解酶-3(caspase-3)活性检测试剂盒检测其活性变化.结果 塞来昔布能够以浓度依赖性方式有效地抑制K562细胞增殖,药物的Ic50为33.98 μmol·L-1;TUNEL染色分析显示给予不同浓度塞来昔布的细胞与未给予塞来昔布的细胞相比凋亡率有差异(P＜0.05),经塞来昔布处理的A549细胞内caspase-3的A405较正常对照组有显著增加(P＜0.05).结论 塞来昔布能够抑制A549细胞增殖,并呈药物浓度依赖性;塞来昔布能以浓度依赖性方式诱导K562细胞凋亡,其机制涉及caspase-3活化的信号转导途径.     

载As2O3白蛋白纳米粒对人K562细胞的增殖抑制作用

目的采用白蛋白纳米粒包载As2O3,通过肿瘤细胞摄取载药纳米粒来增强As2O3对K562细胞的增殖抑制作用。方法采用去溶剂化法制备白蛋白纳米粒(ALB-NP),以异硫氰酸(FITC)标记ALB-NP,荧光显微镜观察K562细胞对ALB-NP的摄取;以ALB-NP包载As2O3制备载As2O3白蛋白纳米粒(As2O3-ALB-NP),MTT法比较As2O3与As2O3-ALB-NP对K562细胞增殖抑制率的差异。结果 As2O3-ALB-NP在低浓度(<0.8μmol.L-1)即可显著抑制K562细胞增殖,而As2O3在该浓度对其无抑制作用。结论与As2O3相比,利用ALB-NP载As2O3可显著增强其对K562细胞的增殖抑制作用,有望实现对As2O3用药的增效减毒,为其用于抗肿瘤治疗提供了新的给药策略。     

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.     

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.     

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.