小剂量反复注射匹罗卡品制备颞叶癫痫大鼠模型

目的：探讨氯化锂-匹罗卡品所致癫痫大鼠模型的新制备方法。方法：利用小剂量多次注射匹罗卡品的方法制备颞叶癫痫大鼠模型后，测取慢性模型组大鼠脑电，计算病灶处的相关维数(Dc值)。结果：此方法使急性期大鼠病死率降至35％，且癫痫持续状态的发生率提高到接近100％。模型组大鼠病灶处脑电Dc值明显降低。结论：小剂量多次注射匹罗卡品是一种更好的颞叶癫痫大鼠模型制备方法。     

小剂量反复注射匹罗卡品建立颞叶癫痫大鼠模型的研究

癫痫是一种中枢神经系统常见疾病,颞叶癫痫是难治性癫痫的常见类型,对癫痫发病机理和抗癫痫药物的研究主要依靠动物实验,迄今尚无一种动物模型能完全模拟人类颞叶癫痫的所有临床、病理、生理学特征.目前常用氯化锂—匹罗卡品腹腔注射法建立癫痫大鼠模型,但所用匹罗卡品的剂量和用法等差异较大,尚无统一标准.已有文献报道使用单次大剂量匹罗卡品腹腔注射法可以获得较高的致痫鼠比率,但致死率较高[1].本实验选择小剂量反复腹腔注射匹罗卡品建立大鼠颞叶癫痫模型,并对所构建的大鼠模型行为学、病理学进行研究,旨在摸索一种能获得较高致痫率及较低致死率的造模方法,现报道如下.     

对锂-匹罗卡品致颞叶癫痫模型大鼠学习记忆功能影响的研究

目的:探讨锂-匹罗卡品致颞叶癫痫模型大鼠自发性癫痫发作后学习记忆功能障碍的情况.方法:建立锂-匹罗卡品颞叶癫痫模型,应用Morris水迷宫和八臂迷宫实验评价颞叶癫痫模型大鼠自发性癫痫发作后的学习记忆功能障碍.结果:颞叶癫痫模型大鼠自发性癫痫发作后,Morris水迷宫和八臂迷宫实验均出现不同程度的障碍,障碍程度随着自发性癫痫发作时间延长而加重.结论:锂-匹罗卡品诱导颞叶癫痫长期自发性癫痫发作后会出现明显的学习记忆功能障碍.     

低频经颅磁刺激对颞叶癫(癇)海马超微结构的影响

目的:研究低频经颅磁刺激(rTMS)对颞叶癫(癇)大鼠海马超微结构的影响.方法:用清洁级Wistar大鼠制备氯化锂-匹罗卡品诱导的颞叶癫(癇)大鼠模型,随机分为对照组和rTMS组,每组5只,对rTMS组大鼠进行rTMS治疗.利用电子显微镜从神经元、神经纤维、突触、胶质细胞和毛细血管5个方面观察颞叶癫(癇)对海马超微结构的病理损伤和rTMS对颞叶癫(癇)海马区病理损伤的作用.结果:颞叶癫(癇)对海马区超微结构具有明显病理损伤,包括神经元出现凋亡和坏死,核浓缩,染色质聚集,线粒体嵴断裂,神经细胞和胶质细胞突起明显水肿,神经纤维局部髓鞘降解,轴浆内微管、微丝排列紊乱,血管内皮细胞肿胀,胶质细胞损伤.rTMS后海马超微结构明显改善,包括脑组织水肿减轻,凋亡和损伤细胞减少,突触和神经毡病变改善和血管水肿减轻.结论:rTMS可改善颞叶癫(癇)对海马超微结构的病理损伤,具有神经保护作用.     

石菖蒲挥发油对锂-匹罗卡品诱发癫痫大鼠c-fos表达的影响

目的探讨石菖蒲挥发油对锂-匹罗卡品（毛果芸香碱）致痫大鼠癫痫发作时间及其脑内c-fos表达的影响。方法选择Wistar大鼠96只,随机分为六组,正常对照组（6只）,模型组（18只）,丙戊酸钠预处理组（18只）,石菖蒲预处理低、中、高剂量组（各18只）。观察石菖蒲挥发油对锂-匹罗卡品致痫大鼠发作时间的影响。以锂-匹罗卡品诱导制作癫痫动物模型,应用免疫组化方法观察石菖蒲挥发油对其脑内c-fos表达的影响。结果石菖蒲低、中、高剂量组大鼠首次抽搐发作时间（SB）和第1次达到Ⅴ级发作时间（RFSⅤS）较模型组明显延长,差异均有统计学意义（P〈0.05）,锂-匹罗卡品致痫大鼠脑内c-fos表达水平明显增强,丙戊酸钠预处理组、石菖蒲预处理高剂量组大鼠海马部位c-fos阳性细胞较模型组及石菖蒲预处理低、中剂量组明显减少,差异均有统计学意义（P〈0.05）。结论该研究方法快速、简便、准确、重现性好,石菖蒲挥发油能缓解锂-匹罗卡品所致的癫痫发作,其作用机制可能与降低脑内c-fos基因表达水平有关。     

氯化锂一匹罗卡品诱发大鼠癫痫持续状态脑内cox-2表达的动态观察

目的:在氯化锂—匹罗卡品诱发癫痫持续状态模型中观察环氧化本酶-2(cox-2)表达的动态变化。方法:采用氯化锂—匹罗卡品诱发癫痫持续状态大鼠模型,观察大鼠的行为改变,并用免疫组化方法观察癫痫持续状态后不同时间点脑内cox-2表达的变化。结果:匹罗卡品诱发癫痫持续状态后12 h、24 h时脑内cox-2表达最高,72 h时表达次之,7 d时极少数表达并接近对照组表达水平。结论:癫痫持续状态后脑内cox-2表达明显增加并且持续很长时间,在此时期如果给予干预措施可以起到减轻癫痫发作和保护神经元的作用。     

氯化锂-匹罗卡品诱发大鼠癫痫持续状态脑内cox-2表达的动态观察

目的:在氯化锂-匹罗卡品诱发癫痫持续状态模型中观察环氧化本酶-2(cox-2)表达的动态变化.方法:采用氯化锂-匹罗卡品诱发癫痫持续状态大鼠模型,观察大鼠的行为改变,并用免疫组化方法观察癫痫持续状态后不同时间点脑内cox-2表达的变化.结果:匹罗卡品诱发癫痫持续状态后12 h、24 h时脑内cox-2表达最高,72 h时表达次之,7d时极少数表达并接近对照组表达水平.结论:癫痫持续状态后脑内cox-2表达明显增加并且持续很长时间,在此时期如果给予干预措施可以起到减轻癫痫发作和保护神经元的作用.     

控制氯化锂-匹罗卡品诱发惊厥持续状态发作的实验研究

目的:探索有效控制氯化锂-匹罗卡品诱发的大鼠惊厥持续状态(SC)发作,提高实验大鼠存活率的最佳条件。方法:选用成年Wistar鼠25只,经腹腔注射氯化锂和匹罗卡品,诱发大鼠惊厥发作,惊厥发作30min后,分为4个不同止惊剂的处理组和1个对照组。比较不同组间的止惊效果、惊厥持续状况、实验动物死亡率、死亡发生时间,探索有效控制氯化锂鄄匹罗卡品所致惊厥持续状态的最佳止惊措施。结果:(1)使用氯化锂鄄匹罗卡品后诱发惊厥的发生率为100%,不采用止惊治疗惊厥发作将持续17~24h,仅有一只存活,其余4只2~4d死亡。(2)与对照组比较,联合使用地西泮和苯巴比妥能在用药后20min左右控制或减轻惊厥发作,但该组实验动物呼吸道分泌物明显增多,呼吸困难严重,所用动物均死于急性肺水肿。(3)腹腔注射水合氯醛后,5~30min能完全终止惊厥发作,但对改善呼吸困难无明显作用,实验动物于(180.0±34.2)min死亡。(4)注射水合氯醛联合应用阿托品后3~29min内完全控制惊厥发作,同时减少实验动物的呼吸道分泌物,改善呼吸困难,使该组5只动物全部存活。结论:水合氯醛是氯化锂鄄匹罗卡品所致SC模型的有效止惊剂;联用水合氯醛和阿托品才是有效控制该模型急性惊厥发作、提高实验动物生存率的措施。     

匹鲁卡品对Wistar大鼠心律失常的影响

目的观察匹罗卡品对Wistar大鼠心律失常的作用。方法分别以乌头碱、氯化钡制作Wistar大鼠心律失常模型,观察0.2 mg.kg-1匹罗卡品舌下静脉注射对心律失常的作用。结果匹罗卡品可明显延迟乌头碱引起Wistar大鼠室性心律失常的出现(P<0.05)、延长其出现心律失常后的存活时间(P<0.05);匹罗卡品能明显延迟氯化钡引起Wistar大鼠双相室性心律失常的出现(P<0.01)、缩短其心律失常的持续时间(P<0.01);但上述作用可被M3受体阻滞剂4-DAMP完全逆转。结论匹罗卡品通过激动Wistar大鼠心肌M3受体而产生对抗乌头碱和氯化钡诱发Wistar大鼠心律失常的作用。     

左乙拉西坦对致痫大鼠海马组织中BMP4表达的影响

目的：建立氯化锂－匹罗卡品幼年大鼠癫痫模型,观察左乙拉西坦对癫痫海马组织中骨形成蛋白（BMP4）表达的影响,以探讨左乙拉西坦的抗癫痫作用机制。方法：将116只21d龄Wistar雄性大鼠随机分为4组,其中空白对照组（NS组）24只、左乙拉西坦对照组（LEV对照组）24只、氯化锂一匹罗卡品模型组（PILO组）34只、氧化锂一匹罗卡品模型＋左乙拉西坦治疗组（LEV治疗组）34只。PILO组和LEV治疗组大鼠首先给予腹腔注射氯化锂（125mg／kg）进行诱导,16h后腹腔注射硫酸阿托品（1mg／kg）,30min后再以匹罗卡品（60mg／kg）腹腔注射,如果没有癫痫发作,可在半小时后,再次腹腔注射匹罗卡品15rag／kg,直至充分点燃建立癫痫模型。其中,LEV治疗组,每日给予左乙拉西坦200mg／kg,连续3周进行灌胃治疗,并分别于1周,2周,3周,处死各组大鼠,并通RT--PCR的方法分别检测及观察海马组织中BMP4表达的变化。结果：PILO组与NS对照组相比,BMP4的表达增加,第1周达高峰（P〈0．01）,第2周、第3周BMP4表达逐渐下降,但较NS对照组仍高表达（P〈0．05）,LEV治疗组与PILO对照组相比,BMP4表达逐渐降低（P〈0．05）,LEV对照组与NS对照组无统计学意义（P〉0．05）。结论：癫痫发作后BMP4表达增加,提示BMP4与癫痫形成密切相关,左乙拉西坦可能通过抑制海马组织中BMP4表达而发挥抗癫痫发作。     

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.     

Synthesis,Cytotoxicity and Antileishmanial Activity of Some N-(2-(indol-3-yl)ethyl)-7-chloroquinolin-4-amines

We report herein the condensation of 4,7-dichloroquinoline (1) with tryptamine (2) and D-tryptophan methyl ester (3) . Hydrolysis of the methyl ester adduct (5) yielded the free acid (6) . The compounds were evaluated in vitro for activity against four different species of Leishmania promastigote forms and for cytotoxic activity against Kb and Vero cells. Compound (5) showed good activity against the Leishmania species tested, while all three compounds displayed moderate activity in both Kb and Vero cells.     

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.     

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.