铜对大鼠学习记忆和海马区超微结构的影响

目的观察铜负荷饮食对大鼠空间学习记忆行为和海马超微结构的影响。方法 40只雄性大鼠随机分为模型组和空白对照组各20只,采用Morris水迷宫实验测试大鼠学习记忆能力,采用原子吸收法检测肝、脑组织铜元素含量,电镜技术观察海马区超微结构变化。结果 Morris水迷宫实验:模型组大鼠在定位航行试验中平均逃避潜伏期较正常对照组显著延长,空间探索试验中穿越平台次数较正常组明显减少(P<0.01),与正常对照组比较,模型组大鼠肝、脑组织铜含量明显增加(P<0.01),海马组织内模型组大鼠神经元突触间隙明显变宽(P<0.05),突触后致密物厚度明显变薄(P<0.05)。结论铜可能通过损伤海马超微结构引起大鼠学习记忆功能障碍。     

淫羊藿苷对侧脑室注射链脲佐菌素所致大鼠学习记忆损伤的保护作用

目的观察淫羊藿苷(Ica)对侧脑室注射链脲佐菌素(STZ)所致大鼠痴呆模型的保护作用。方法雄性SD大鼠分为假手术组、STZ模型组、Ica给药组。除假手术组外,所有大鼠双侧侧脑室注射STZ(3 mg·kg-1)模拟散发性老年性痴呆,假手术组只注射等体积的溶剂,制模前后分别给予Ica(40 mg·kg-1·d-1)灌胃3周。给药结束后采用Morris水迷宫观察大鼠行为学改变,血糖仪检测空腹血糖,收集海马组织观察乙酰胆碱酯酶(Ach E)和转化生长因子β1(TGF-β1)蛋白表达情况。结果侧脑室注射STZ后Morris水迷宫结果显示大鼠找到水下平台的逃避潜伏期显著延长(P<0.05),记忆功能受损,海马组织Ach E和TGF-β1蛋白水平增高(P<0.05),而双侧侧脑室注射STZ并不影响大鼠空腹血糖值(P>0.05);给予Ica后大鼠逃避潜伏期缩短(P<0.05),海马组织Ach E和TGF-β1蛋白高表达状态缓解(P<0.05)。结论 Ica对侧脑室注射STZ引起认知功能损伤具有保护作用,其机制可能与改善海马组织Ach E和TGF-β1蛋白的高表达相关。     

己酮可可碱和咯利普兰对淀粉样β蛋白诱导脑损伤后学习记忆功能的影响

目的探讨磷酸二酯酶抑制剂对淀粉样β蛋白(Aβ)诱导的脑损伤大鼠学习记忆功能的改善作用及可能机制。方法SD大鼠分为假手术对照组、模型组、己酮可可碱(PTX)16.5mg.kg-1组和咯利普兰1mg.kg-1组。模型组及给药组大鼠两侧海马内分别注射Aβ25-355μL,术后24h给药组ip给药,每日1次,连续14d。给药7d后进行避暗实验,14d后进行Morris水迷宫实验观察行为学变化。之后处死大鼠,用放射免疫法测定海马组织cAMP含量。结果与模型组比较,PTX组和咯利普兰组大鼠在避暗实验中潜伏期明显延长,在水迷宫实验中寻台时间明显缩短,海马组织cAMP水平显著升高。结论升高脑内cAMP水平可能是磷酸二酯酶抑制剂PTX和咯利普兰增强Aβ脑损伤大鼠学习记忆功能的机制之一。     

天麻素对海马内Aβ1-40注射阿尔茨海默病模型大鼠学习记忆的改善作用

目的:观察天麻素对海马内β-淀粉样蛋白1-40(Aβ1-40)注射阿尔茨海默病(Alzheimer dis-ease,AD)模型大鼠空间学习记忆能力的影响。方法:双侧海马内注射Aβ1-40建立AD大鼠模型,并设注射生理盐水的假手术组(n=7)和不作处理的正常组(n=10);AD模型大鼠分设天麻素组、石杉碱甲组和模型组(各n=8),分别给予药物或生理盐水灌胃4周(q.d.)后,用Morris水迷宫进行学习记忆能力检测。结果:与正常组或假手术组相比,模型组大鼠在Morris水迷宫的定位航行试验中逃避潜伏期明显延长(P<0.01或P<0.05)。与模型组比较,天麻素组大鼠的逃避潜伏期明显缩短(P<0.05),且空间探索试验中在原平台所在象限停留时间明显延长(P<0.05)。结论:天麻素对海马内Aβ1-40注射AD模型大鼠的学习记忆损害有一定的改善作用。     

葛根提取物对阿尔茨海默病大鼠学习记忆能力的影响

目的:观察葛根提取物对阿尔茨海默病大鼠的学习记忆能力的影响。方法:Morris水迷宫筛选学习记忆正常SD大鼠72只,随机分为假手术组12只,手术组60只,在脑定位仪定位下,手术组大鼠微量注射凝聚态β淀粉样蛋白25-35(beta-amyloid peptide 25-35)至海马内侧脑室以建立阿尔茨海默病(AD)模型;假手术组注射等量生理盐水。Morris水迷宫筛选模型成功大鼠,随机分为模型组、0.42mg.kg-1多奈哌齐治疗组、0.47g.kg-1、0.24g.kg-1、0.12g.kg-1葛根提取物治疗组和假手术组,每组10只SD大鼠。治疗组灌胃给药,每日一次,连续四周;Morris水迷宫测试各组大鼠学习记忆能力。结果:(1)与假手术组比较,手术组大鼠学习记忆能力明显降低(P0.01)。(2)与模型组相比,多奈哌齐组、0.47 g.kg-1.d-1、0.24 g.kg-1和0.12 g.kg-1.d-1葛根提取物组均可使大鼠的逃避潜伏期变短(P0.05,P0.01),可使大鼠跨越平台次数及在平台象限游程百分比均增加(P0.05)。(3)各剂量组之间比较,于定位航行的第四、五天,大鼠逃避潜伏期差异明显(P0.05)。结论:1.大鼠侧脑室内注射Aβ25-35成功制备了大鼠AD模型。2.葛根提取物可改善AD大鼠的学习记忆能力,是否具有剂量依赖性,还需进一步研究。     

知母总皂苷对老年大鼠学习记忆行为和海马突触相关蛋白表达的影响

目的探讨知母总皂苷(SAaB)对老年大鼠学习记忆能力及突触相关蛋白表达的影响。方法 ig给予18个月龄SD大鼠SAaB 100和200 mg.kg-1,每天1次,连续9周,第8周开始进行Morris水迷宫实验,记录逃避潜伏期及各象限游泳时间。免疫组织化学法观察海马突触素蛋白(SYP)分布。Western印迹法检测CA3区SYP、突触后致密蛋白95(PSD95)、磷酸化蛋白激酶B(p-Akt)和磷酸化雷帕霉素靶蛋白(p-mTOR)蛋白分布。结果与青年大鼠对照组比较,老年对照组大鼠逃避潜伏期显著增加,原平台象限游泳时间占总时间的百分比显著缩短(P<0.05),海马SYP,PSD95,p-Akt和p-mTOR表达显著降低(P<0.01)。与老年对照组相比,给予SAaB后,青年大鼠逃避潜伏期显著缩短,原平台象限游泳时间占总时间的百分比显著增加(P<0.05);海马SYP,PSD95,p-Akt和p-mTOR表达显著增加(P<0.01)。结论 SAaB能显著改善老年大鼠学习记忆能力,可能与上调SYP和PSD95表达及激活Akt/mTOR信号通路有关。     

吡格列酮对糖尿病大鼠认知功能及海马组织TNF-α、Aβ的影响

目的:观察吡格列酮对糖尿病大鼠认知功能及海马组织TNF-α、β-淀粉样蛋白(Aβ)的影响。方法:随机将45只Wistar大鼠分为正常对照组、糖尿病组、吡格列酮组,STZ25mg.kg-1腹腔注射建立糖尿病大鼠模型,给予吡格列酮10mg.kg-1.d-1灌胃干预12周后,采用Morris水迷宫试验测试其认知能力,ELISA法检测各组大鼠海马组织TNF-α和Aβ表达。结果:吡格列酮组与糖尿病组Morris水迷宫测试中逃避潜伏期分别较正常对照组明显延长(P<0.05);与糖尿病组比较,吡格列酮组Morris水迷宫测试中潜伏期明显缩短(P<0.05);中心区停留时间百分比和通过原平台位置次数增加(P<0.05);TNF-α表达吡格列酮组和糖尿病组与对照组相比明显升高(P<0.01);Aβ表达吡格列酮组和糖尿病组与对照组相比明显升高(P<0.01);吡格列酮组TNF-α和Aβ表达较糖尿病组降低(P<0.05)。结论:糖尿病大鼠认知功能受损;吡格列酮对糖尿病大鼠的认知功能减退具有改善作用,其机制可能与海马组织TNF-α、Aβ的表达降低有关。     

蛇床子素减轻脂多糖诱导的大鼠学习记忆减退

目的观察蛇床子素对脂多糖诱导的大鼠学习记忆减退的作用,并初探其可能的作用机制。方法 40只雄性SD大鼠随机分为假手术组、模型组、阳性药组及蛇床子素组。阳性药组、蛇床子素组分别每日1次灌胃布洛芬、蛇床子素40 mg.kg-1,连续12 d,假手术组、模型组灌胃等体积的生理盐水,3 d后侧脑室注射脂多糖诱导大鼠的神经炎症模型,制模后d 5开始Morris水迷宫检测大鼠的空间记忆能力,连续5 d。Morris水迷宫检测结束后,处死大鼠,HE染色观察大鼠海马神经元损伤情况,real time RT-PCR法测定海马肿瘤坏死因子α(Tnf-α)、白细胞介素-1β(Il-1β)、诱导型一氧化氮合酶(Nos2)及环氧合酶-2(Cox-2)的mRNA表达。结果侧脑室注射脂多糖后,大鼠在定向航行实验中的逃避潜伏期显著增加(P<0.05),空间探索实验中的校正逃避潜伏期缩短(P<0.05),海马神经元明显受损,且海马Tnf-α、Il-1β、Nos2及Cox-2的mRNA表达增加(P<0.05);然而,蛇床子素及布洛芬明显缩短了大鼠的定向航行实验中的逃避潜伏期(P<0.05),延长了空间探索实验中的校正逃避潜伏期(P<0.05),减轻了海马神经元损伤,且降低海马Tnf-α、Il-1β、Nos2及Cox-2的mRNA表达。结论蛇床子素可减轻脂多糖诱导的大鼠学习记忆减退及海马神经元损伤,其机制与抑制炎症相关基因的mRNA表达有关。     

丁苯酞软胶囊对脑缺血痴呆大鼠记忆能力的影响

目的观察丁苯酞软胶囊(dl-3n-butylphthalide,NBP)对脑缺血(cerebral infarction,CI)大鼠学习记忆能力的影响。方法 SD大鼠随机分为正常组、假手术组、模型组、治疗组与对照组。采用自体血栓法制作CI痴呆(vascular dementia VD)模型。治疗组采用NBP灌胃,对照组采用尼莫地平治疗,给药时间30 d。模型组、假手术组和正常组均给予生理盐水灌胃。治疗后以Morris水迷宫检测其学习记忆行为能力,HE染色检测梗死灶周围组织形态学改变。结果 Morris水迷宫实验中,与正常组比较,模型组大鼠逃避潜伏期明显延长(P<0.05),平均探索次数显著减少(P<0.05);与模型组比较,治疗组、对照组大鼠逃避潜伏期明显缩短(P<0.05),平均探索次数显著增加(P<0.05)。光镜观察显示,与模型组相比,治疗组和对照组均可见海马CA1区神经元数目明显增多,变性坏死细胞减少。结论 NBP可以改善VD大鼠学习记忆能力,其机制可能与抑制CI区细胞凋亡,保护海马CA1区细胞有关。NBP对CI后神经细胞有明显保护作用。     

文冠果壳提取物对β-淀粉样蛋白致动物学习记忆障碍的改善作用

目的研究文冠果壳乙醇提取物对动物学习记忆障碍的改善作用并探讨其可能的作用机制。方法采用水迷宫法、避暗法测定小鼠的学习记忆能力;用Y迷宫法及Morris水迷宫法测试大鼠的学习记忆能力,显微镜下观察海马组织形态学改变。结果文冠果壳乙醇提取物显著减少侧脑室注射β-淀粉样蛋白(25-35)(Aβ(25-35))致记忆障碍小鼠水迷宫实验的逃避潜伏期和避暗实验的错误次数,延长避暗潜伏期;文冠果壳乙醇提取物显著提高D-半乳糖合用Aβ(25-35)致记忆障碍大鼠Y迷宫测试中正确反应率,显著缩短Morris水迷宫测试中的潜伏期及游泳路程;抑制海马神经元的变性及脱落。结论文冠果壳乙醇提取物对Aβ(25-35)致鼠学习记忆障碍有显著的改善作用,其作用机制可能与对抗Aβ(25-35)的毒性有关。     

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.     

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.