瑞香素抗血栓作用

瑞香素80 mg/kg iv对大鼠实验性血栓形成有明显的抑制作用,抑制率54%,在试管内当浓度为0.025,0.05及0.1 mg/ml时,可抑制ADP诱导的家兔血小板聚集。iv 80 mg/kg 5 min,对ADP诱导的家兔血小板聚集也有明显的抑制作用。iv 40及80 mg/kg 20 min,皆可使血小板粘附性降低;并能延长小鼠凝血时间。iv 80 mg/kg 5 min,对家兔纤维蛋白原含量,全血粘度及血浆比粘度均无明显影响。     

刺五加茎时对血小板聚集功能的影响

刺五加茎叶的乙醇提取液相当于生药量25～70mg/ml,体外实验能明显地抑制ADP、胶原所诱导的家兔血小板聚集。家兔iv 700mg/kg,10min后明显抑制ADP诱导的家兔血小板聚集,大白鼠iv 1000mg/kg,30min后明显抑制ADP诱导的血小板聚集。体外实验可使家兔血浆复钙时间明显延长。     

单甘酯对血小板功能及纤维蛋白原含量的影响

目的 :研究单甘酯对血小板聚集、粘附功能及出血时间和纤维蛋白原含量的影响。方法 :比浊法观察血小板聚集功能 ,玻瓶法观察血小板粘附功能 ,小鼠剪尾法观察出血时间 ,比色法测定纤维蛋白原含量。结果 :单甘酯 2 5、5 0mg/kg对血小板粘附有明显抑制作用 ,2 5、5 0、10 0mg/kg(iv)能明显抑制胶原和花生四烯酸诱导的血小板聚集 ,对ADP诱导的血小板聚集无抑制作用 ;40、80mg/kg(ip)可明显延长小鼠尾出血时间 ;2 5mg/kg(iv)即可降低大鼠血浆纤维蛋白原含量。结论 :单甘酯有明显的抑制血小板功能和降低血浆蛋白原含量的作用。     

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。     

夏天无总碱对大鼠血小板功能的影响

夏天无总碱(COAMTA)体外实验和体内给药都明显抑制ADP诱导的大鼠血小板聚集,并明显抑制血栓的形成和血小板粘附。COAMTA iv 0.3mg/kg对大鼠实验性血栓形成有明显的抑制作用,抑制率为31.3%。提示上述作用可能是该药治疗脑血管栓塞等疾病有效的机理之一。     

溶栓1号抗血小板聚集及抗血栓形成作用

溶栓 1号是从蚯蚓中提取的酸性蛋白酶 ,并经进一步纯化 ,可静脉给药考察对ADP诱导的家兔血小板聚集的抑制作用 ;并采用小鼠肺血栓模型 ,电刺激致家兔颈动脉血栓模型及穿线法形成家兔颈动脉血栓模型 3种实验性血栓模型 ,考察溶栓 1号的抗血栓形成作用。实验结果表明 :溶栓 1号静脉注射给药 (1 5 0、3 0 0、60 0u/kg)可明显抑制ADP诱导的家兔血小板聚集作用 ,并可明显抑制小鼠肺血栓、家兔颈动脉血栓的形成。溶栓 1号抑制血栓形成可能与抑制血小板活性有关     

尼群地平的抗血小板聚集和抗血栓作用

国产尼群地平(1)对凝血酶(0.15u/ml)诱导的血小极聚集的 IC_(50)是47.5μmol/L,对 ADP(4μmol/L)诱导作用的 IC_(50)是93.9μmol/L。大鼠 iv 1 0.8μg/g 对凝血酶诱导血小板聚集的抑制率为89.8%,对 ADP、AA 诱导血小板聚集的效应也有非常显著的抑制作用。1尚可明显抑制血栓形成。     

当归及其成分阿魏酸对大鼠血小板聚集和5-HT释放的影响

本文报告当归及其成分阿魏酸对大鼠血小板聚集性和5-HT释放反应的影响。结果表明,当归水剂在试管内当浓度为200～500mg/ml,阿魏酸0.4～0.6mg/ml时抑制ADP和胶原诱导的大鼠血小板聚集。静脉注射当归20g/kg 5分钟后对ADP和胶原诱导的大鼠血小板聚集有明显的抑制作用。阿魏酸钠0.2g/kg和0.1g/kg静脉注射时分别抑制ADP和胶原诱导的大鼠血小板聚集。用³H-5HT标记血小板,观察血小板聚集和释放反应的关系。当归水剂500mg/ml和阿魏酸钠1～2mg/ml对凝血酶诱导的血小板聚集有明显抑制作用,同时也抑制³H-5HT从血小板中释放。     

哒嗪酮类新化合物9612的抗血小板聚集作用

研究了新型哒嗪酮类化合物 96 12对家兔和大鼠血小板聚集的影响 .结果发现 ,96 12在体外能明显抑制花生四烯酸 (AA) ,腺苷二磷酸 (ADP)和凝血酶 (thrombin)诱导的家兔血小板聚集 ,其IC50 分别为 3 2 0 ,9 44和 7 10 μmol/L .96 12 .灌胃给药 (ig) ,能显著抑制AA和ADP诱导的大鼠血小板聚集 ,其作用与同等剂量 (15 0mg/kg)的阿斯匹林 (ASA)相比无明显差异 (P >0 0 5 ) .     

香草酸抗血小板聚集作用的体内外研究

目的香草酸是一种酚酸类化合物,具有抗氧化、抗炎等药理作用,其抗血栓作用尚未有报道。本实验室前期通过筛选发现香草酸具有良好的抗血小板聚集作用,因此本研究通过体内外实验对香草酸抗血小板聚集的作用进行系统评价。方法采用花生四烯酸(arachidonic acid,AA)、二磷酸腺苷(adenosine diphosphate,ADP)、凝血酶(thrombin,THR)诱导体内外血小板聚集模型,结合凝血四项检测评价香草酸抗血小板聚集及抗血栓的作用。结果体外实验中,香草酸对ADP和AA诱导的血小板聚集具有显著抑制作用,并剂量依赖性抑制ADP诱导的血小板聚集;体内试验中,香草酸(10、30和100 mg/kg)能够剂量依赖性抑制ADP和AA诱导的血小板聚集;同时,香草酸(100 mg/kg)能显著降低纤维蛋白原、增加凝血酶原时间,对活化部分凝血活酶时间和血浆凝血酶时间无明显影响。结论本研究首次发现香草酸对ADP和AA诱导的血小板聚集具有抑制作用,为研发具有自主知识产权的抗血小板聚集药物提供了实验依据。     

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.