甲基莲心碱对正常与高脂血人及动物血小板聚集功能的影响

用比浊法测定血小板聚集率,观察甲基莲心碱(Nef)体外给药对正常与高脂血的人、大鼠及家兔血小板聚集功能的影响。结果表明,Nef在体外抑制ADP、胶原、Adr诱导的人血小板聚集,呈明显剂量依赖性。健康人组,对ADP、Adr诱聚1min时的IC_(50)分别为59和36μmol/L;对ADP、Adr、胶原诱聚5min时的IC_(50)分别为42,89和110μmol/L。高脂血症患者组,Nef对ADP、Adr诱聚1min时的IC_(50)分别为45,38μmol/L;对ADP、Adr、胶原诱聚5min时的IC_(50)分别为36,27和16μmol/L。Nef 50、500μmol/L也能明显抑制ADP诱导的以正常或高脂饮食喂养大鼠的血小板聚集。Nef(0.3～300μmol/L)抑制ADP、胶原诱导的兔血小板聚集呈剂量依赖性。     

四肽KRDS对犬血小板功能及动脉血栓形成的抑制作用

来自人乳转铁蛋白的四肽(赖—精—门冬—丝氨酸,K RDS)能抑制ADP诱导的犬血小板聚集反应(IC_(50):350μmol/L)和花生四烯酸诱导的血栓烷B_2的产生(IC_(50):175μmol/L),同时,KRDS能抑制凝血酶诱导的血小板表面α—颗粒膜蛋白(GMP-140)的表达(IC_(50):350μmol/L及5—羟色胺的释放(IC_(50):525μmol/L)。另外,KRDS能抑制犬股动脉实验血栓的形成,制备血栓模型4h后,离体血栓的重量为对照组的50%,以~(125)Ⅰ—SZ-51(抗GMP-140的单抗)为示踪剂,离体血栓与血液的放射活性比值仅为对照组的16%。结果提示:四肽KRDS不仅能抑制犬血小板的聚集和释放功能,对体内血栓的形成也有明显的抑制作用,为一生理性抗血栓寡肽。     

海兰地嗪对血小板聚集的影响及机理探讨

海兰地嗪(Her)体外对胶原,ADP,A23187和AA诱导的大鼠血小板聚集有明显抑制作用,其IC_(50)分别为14.5,41.6,44.1和48.3μg/ml。Her对AA诱导的大鼠血小板MDA生成不能抑制,但能升高兔血小板cAMP水平和抑制凝血酶诱导的人血小板胞浆内游离钙离子浓度升高。Her的抗血小板聚集作用机理可能与升高血小板内cAMP水平和抑制细胞内游离钙离子浓度升高有关。     

奥昔麻黄碱对凝血酶诱导家兔血小板聚集和丙二醛生成的影响

Oxy明显地抑制凝血酶诱导洗涤的兔血小板聚集,IC_(50)为254μmol/L,对MDA的生成也有抑制作用。ASA不能对抗凝血酶引起的血小板聚集,但能显著抑制MDA的生成。提示,Oxy抑制血小板聚集的作用可能与影响PAF生成有关,对MDA生成的抑制可能影响了AA的游离。     

六肽对兔血小板聚集活性的影响

目的研究六肽对兔血小板聚集活性的影响。方法采集健康家兔颈动脉血,以枸橼酸钠抗凝,用比浊法测其血小板在不同诱导剂诱导下聚集率。结果 1×10 5mol.L 1六肽,对兔ADP、花生四烯酸(AA)和凝血酶诱导的血小板聚集的抑制率分别为(66.22±1.40)%,(67.94±2.32)%和(58.18±4.67)%。六肽抑制兔ADP、AA和凝血酶诱导的血小板聚集的IC50分别为3.24×10 6mol.L 1,1.32×10 6mol.L 1和7.24×10 6mol.L 1。结论六肽在体外具有抑制兔血小板聚集的作用。     

赤子爱胜蚓血小板聚集因子对血小板的活化作用(英文)

赤子爱胜蚓血小板聚集剂(EPAF,25.9μmol·L~(-1))能诱导人血小板聚集。EPAF为74.1μmol·L~(-1)时引起5-羟色胺最大释放(89％)。ADP受体拮抗剂(CP/CPK)和阿司匹林均不能抑制EPAF引起的人血小板聚集反应;EPAF(55.6μmol·L~(-1))能诱导凝血酶处理后脱颗粒人血小板产生聚集,表明EPAF诱导。的血小板聚集不依赖于ADP和TXA_2,是一种强血小板激动剂。     

BM13505对血小板聚集和血栓形成的影响

BM13505在体外对花生四烯酸(AA)诱导的家兔血小板聚集有抑制作用且呈剂量依赖性,其IC_(50)为20μmol/L;对 ADP 和胶原诱导的血小板聚集则无显著影响。大鼠 ivBM13505 0.23mg/kg 能显著,延长血管闭塞时间,与阿司匹林30mg/kg 药效相近。小鼠 ivBM13505 1.13mg/kg 可明显延长尾出血时间效应与阿司匹林30mg/kg 相近。     

益康唑和克霉唑对血小板聚集及TXB_2和PGE_2生成的影响

益康唑,克霉唑,咪康唑和酮康唑体外抑制AA诱导兔血小板聚集比抑制ADP诱导大鼠血小板聚集的作用强。其中益康唑和克霉唑抑制AA诱聚兔血小板的IC_(50)分别是6.4及11.6μmol/L。放射免疫法测定大鼠血小板产生的TXB_2及PGE_2发现益康唑和克霉唑在5～50 nmol/L浓度下,能抑制TXB_2产生,同时增加PGE_2生成量,并呈良好的剂量效应相关。浓度为0.1～100μmol/L时,TXB_2的生成仍被抑制,而PGE_2的生成量反而逐渐降低。两药对TXB_2生成的抑制作用比Daz强。     

牛心内膜腺苷三磷酸双磷酸酶对血小板聚集的抑制作用(英文)

目的:研究牛心内膜内皮细胞(EEC)腺苷三磷酸双磷酸酶的抗血小板聚集效应。方法:培养牛EEC。以高效液相色谱法测定ADP,用比浊法测血小板聚集。结果:ADP 500μmol·L~(-1)与EEC温孵后,引起ADP浓度进行性地降低。与此相适应的是,未代谢的ADP诱导血小板聚集的能力也降低。在阿司匹林处理过的EEC 1×10~9cells·L~(-1)存在下,凝血酶500U·L~(-1)及PAF 1nmol·L~(-1)诱导的经阿司匹林1mmol·L~(-1)及亚甲基蓝10μmol·L~(-1)处理过的血小板聚集明显受到抑制,且聚集是可逆的;EEC的此种作用类似于腺苷三磷酸双磷酸酶的作用。EEC明显抑制ADP 5μmol·L~(-1)诱导的血小板聚集,但不能抑制ADP-β-S 15μmol·L~(-1)诱导的血小板聚集。结论:腺苷三磷酸双磷酸酶水解ADP是牛EEC重要的抗血栓机制。     

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮对兔血小板聚集及TXB_2,cAMP的影响

6-(αα-二苯基乙酰哌嗪基苯基)-4,5-二氢-5-甲基-3(2H)-哒嗪酮(简称DMDP)是我院新合成的哒嗪酮的衍生物。DMDP可以显著抑制由花生四烯酸(AA(?),ADP和血小板活化因子(PAF)诱导的免血小板聚集,其IC_(50)分别为1.12±0.1.4.19±0.5和2.97±0.1μmol/L。实验还表明DMDP在1～500 μmol/L浓度范围内呈剂量依赖性地抑制兔血小板内血栓素B_2含量,但升高兔血小板内环腺苷酸水平,这可能是其抑制血小板聚集的作用机理之一。     

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.