左旋四氢巴马汀对大鼠局灶性脑缺血-再灌注损伤后海马CA1区Fas和FasL蛋白表达的影响

［摘要］目的探讨左旋四氢巴马汀（L THP）对大鼠局灶性脑缺血 再灌注损伤的保护作用及对海马CA1区凋亡蛋白Fas、FasL表达的影响。方法参照改良Longa法建立局灶性脑缺血 再灌注模型,应用Image Pro Plus6.0专业图像分析软件测定脑梗死体积,比色法测定肌酸激酶（CK）活力,用免疫组化法分别检测缺血侧海马CA1区Fas、FasL阳性表达。结果与模型组比较,L THP能够缩小局灶性脑缺血 再灌注损伤大鼠脑梗死体积,降低血清CK活力,降低缺血侧海马CA1区Fas、FasL凋亡蛋白的表达。结论L THP可能通过抑制神经元凋亡蛋白Fas、FasL表达,而对脑组织起到保护作用。     

消旋四氢巴马汀对局灶性脑缺血 再灌注损伤模型大鼠的保护作用

目的 观察消旋四氢巴马汀（THP）对局灶性脑缺血 再灌注损伤大鼠的保护作用。方法用改良LONGA法制作大鼠局灶性脑缺血 再灌注损伤模型,缺血前15 min 腹腔注射THP10.0,5.0,2.5 mg•kg 1,观察缺血3 h再灌注3 h后大鼠神经功能障碍、脑梗死范围、血清乳酸脱氢酶（LDH）和肌酸激酶（CK）含量,脑组织钙、水、丙二醛（MDA）和超氧化物歧化酶（SOD）含量,以及脑超微结构。结果THP能剂量依赖性降低神经功能行为评分,缩小脑梗死范围,抑制血清LDH、CK活力升高;THP10.0 mg•kg 1可明显减轻脑水肿,减轻脑超微结构损害,提高脑组织SOD活性,降低MDA含量和脑组织钙聚集。结论THP对局灶性脑缺血 再灌注损伤模型大鼠有一定保护作用,其作用机制可能与抑制脑组织钙聚集、抗脂质过氧化反应有关。     

双苯氟嗪对大鼠全脑缺血再灌注损伤的保护作用

目的研究双苯氟嗪(D ip)对大鼠急性全脑缺血再灌注损伤的保护作用,并初步探讨其作用机制。方法采用Pu lsinelli等的四动脉结扎法(4-VO)造成大鼠全脑缺血再灌注损伤模型,观察大鼠全脑缺血再灌注损伤后早期脑组织水分的变化、生化指标的改变,再灌注后期行为学和组织形态学的改变。结果缺血30 m in再灌注1 h脑组织水分及丙二醛(MDA)含量升高,乳酸脱氢酶(LDH)和超氧化物歧化酶(SOD)活性下降;缺血20 m in再灌注5 d后海马CA1区椎体细胞层破裂,胞核固缩或溶解,间质也变得疏松。行为学实验表明大鼠记忆力明显受损。D ip可不同程度地抑制上述变化,能对抗自由基损伤和脑水肿,并能保护海马CA1区神经元免受缺血损伤,提高大鼠对空间辨别的记忆能力。结论D ip对大鼠全脑缺血再灌注早期损伤有明显的保护作用,并能保护海马CA1区神经元免受缺血损伤,提高大鼠对空间辨别的记忆能力,对迟发性神经元死亡有一定的保护作用。这可能与其抗脂质过氧化产物产生有关。     

垂体腺苷酸环化酶激活肽对大鼠局灶性脑缺血/再灌注损伤脑保护作用的研究

目的观察垂体腺苷酸环化酶激活肽(PACAP)对大鼠局灶性脑缺血/再灌注损伤的脑保护作用。方法采用线栓法制备大鼠局灶性脑缺血/再灌注损伤(MCAO)模型,缺血前经侧脑室分别给予不同剂量的PACAP,脑缺血2 h/再灌注24 h,测定脑含水量、脑组织超氧化物歧化酶(SOD)活性和丙二醛(MDA)、一氧化氮(NO)含量。结果与NS组相比,PACAP各组脑含水量、MDA及NO含量均明显降低,SOD活性有不同程度的提高。结论PACAP对大鼠局灶性脑缺血/再灌注损伤有明显的脑保护作用,中、高剂量组效果优于低剂量组,其机制可能与减轻脑水肿、清除自由基、抗脂质过氧化有关。     

左旋四氢巴马汀对局灶性脑缺血再灌注大鼠凋亡蛋白P53、HSP70表达的影响

目的：观察左旋四氢巴马汀（L-THP）对局灶性脑缺血再灌注损伤的保护作用及对神经元凋亡蛋白P53、HSP70表达的影响,探讨L-THP的神经保护作用及机制.方法：采用改良Longa法建立局灶性脑缺血再灌注模型,11分法对大鼠进行神经行为症状评分,比色法测定大鼠血清乳酸脱氢酶（LDH）活力,HE染色观察大鼠脑组织神经元病理形态学变化,免疫组织化学染色法分别检测缺血侧海马CA1区P53、HSP70阳性细胞表达.结果：L-THP能够明显改善局灶性脑缺血再灌注损伤大鼠神经行为症状以及脑组织形态结构,降低血清LDH活力,并且能够降低大鼠海马CA1区P53蛋白的阳性表达,在再灌注早期增强HSP70的阳性表达.结论：L-THP对局灶性脑缺血再灌注损伤具有保护作用,其作用机制可能与抑制凋亡蛋白P53的表达,增强HSP70的表达有关.     

茅莓水提取物对大鼠局灶性脑缺血-再灌注的保护作用

目的:研究茅莓水提取物对局灶性脑缺血-再灌注的保护作用。方法:采用大脑中动脉线栓法制备大鼠局灶性脑缺血／再灌注模型;以HE染色观察神经元形态病理改变,用氯化三苯四氮唑(TTC)染色法测定脑梗死范围,采用测试药盒测定超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSH-Px)活性、丙二醛(MDA)含量。结果:茅莓水提取物1,2 mL·kg-1可明显减轻神经元形态病理改变,改善大鼠异常神经症状,使脑缺血-再灌注大鼠缺血区脑组织的SOD,GSH-Px活力提高,MDA含量减少。结论:茅莓水提取物对脑梗死有保护作用,其作用机制可能与抗自由基有关。     

NGF对局灶性脑缺血/再灌注大鼠海马tau蛋白磷酸化作用的影响

目的探讨外源性神经生长因子(NGF)对局灶性脑缺血/再灌注大鼠海马神经元tau蛋白过度磷酸化的影响。方法用线栓法制作局灶性脑缺血/再灌注模型,应用免疫组织化学SABC法、Westernblot和图像分析方法检测大鼠海马CA1区tau蛋白在Ser199/202位点磷酸化程度和总tau蛋白表达,以及NGF对tau蛋白过度磷酸化的影响。结果缺血/再灌注组海马CA1区tau蛋白在Ser199/202位点磷酸化水平和总tau蛋白明显升高(P<0·05);NGF组大鼠海马tau蛋白在Ser199/202位点磷酸化水平明显低于缺血/再灌注组,总tau也下降(P<0·05)。结论NGF明显减轻局灶性脑缺血/再灌注大鼠海马tau蛋白磷酸化程度,降低tau蛋白磷酸化水平可能对缺血神经元起保护作用。     

依达拉奉对大鼠脑缺血再灌注后自由基含量的影响

目的通过观察雄性大鼠脑缺血再灌注后SOD活力、MDA、NO的表达,探讨依达拉奉的脑保护作用。方法选用雄性SD大鼠30只,随机分为3组:假手术(SO)组、缺血再灌注(I/R)组和依达拉奉(ED)组,每组10只。建立大鼠右侧大脑中动脉闭塞局灶性脑缺血再灌注模型,用生化法测定3组脑缺血再灌注后SOD活力、MDA、NO含量。结果 ED组及SO组脑组织SOD活力均高于I/R组(P<0.05),MDA及NO含量显著低于I/R组(P<0.05)。结论依达拉奉能增强SOD活力、减少MDA及NO含量,改善自由基代谢,有效减轻缺血再灌注损伤后的脑损伤。     

复方沙棘2号颗粒对大鼠局灶性脑缺血再灌注损伤的保护作用及机理探讨

目的：研究复方沙棘2号颗粒对大鼠局灶性脑缺血再灌注损伤的保护作用及作用机理。方法：线栓法制作局灶性脑缺血再灌注模型。检测脑梗死体积比，血清MDA含量，血清SOD和GSH－Px活性，并观察行为学改变。结果：大鼠脑缺血再罐注后，血清MDA含量和脑梗死体积比显增加，SOD和GSH—Pk活力明显下降。复方沙棘2号可有效地防止上述改变。结论：复方沙辣2号颗粒对脑缺血再灌注损伤有显保护作用。这种保护作用可能与提高脑组织抗脂质过氧化能力有关。     

尿酸对大鼠局灶性脑缺血保护作用及其机制研究

目的初步探讨外源性给予尿酸对脑缺血的保护作用及其机制。方法大脑中动脉线栓法制作大鼠局灶性脑缺血再灌注模型。动物随机分为假手术组、缺血模型组、溶媒对照组、尿酸(62.5 mg·kg-1.d-1,93.75 mg·kg-1.d-1)治疗组、阿司匹林阳性对照组。手术后断头取脑,行神经行为学评分和TTC染色法判断神经元损伤程度。取缺血侧皮质组织,分光光度法测定丙二醛(MDA)、一氧化氮(NO)、黄嘌呤氧化酶(XO)含量和超氧化物歧化酶(SOD)、谷胱甘肽过氧物酶(GSH-Px)活力的变化;用ELISA方法检测神经元型一氧化氮合酶(nNOS)含量变化。结果尿酸可以改善脑缺血再灌注大鼠神经行为学评分(P<0.05)、降低脑缺血再灌注大鼠皮质损伤(P<0.05),从而起到神经保护作用。尿酸可减少缺血侧皮质组织MDA,XO含量(P<0.05)、抑制SOD,GSH-PX活力升高(P<0.05),并降低nNOS含量。结论尿酸可通过其抗氧化应激效应以及降低nNOS和XO含量对大鼠局灶性脑缺血发挥保护作用。     

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.