褪黑激素降低脑缺血再灌注中羟自由基的生成

目的：研究褪黑激素对大鼠脑缺血再灌注中羟自由基生成的影响。方法：采用栓线法阻塞左侧ＭＣＡ３０ｍｉｎ再灌注模型。通过水杨酸捕获法与微透析技术结合来观察缺血再灌中羟自由基含量的变化。结果：ＤＨＢＡ水平在缺血１５ｍｉｎ后显升高，持续到再灌注后３０ｍｉｎ仍维持较高水平。缺血前３０ｍｉｎ给予ｍｅｌａｔｏｎｉｎ（４ｍｇ·ｋｇ＾－１，ｓｃ）显降低缺血１６￣３０ｍｉｎ及再灌注１－３０ｍｉｎ时ＤＨＢＡ的含量。结     

沙棘总黄酮对大鼠心肌再灌注损伤的保护作用

目的：观察沙棘总黄酮对大鼠心肌再灌注损伤时超微结构及对心肌组织ＳＯＤ活性和ＭＤＡ含量的影响。方法：预先ｉｇ沙棘总黄酮（ＴＦＨ）６ｄ后，用ＳＤ大鼠制作心肌缺血再灌注模型。结果：缺血４０ｍｉｎ，再灌３０ｍｉｎ后ＴＦＨ（７７ｍｇ·ｋｇ－１、２３１ｍｇ·ｋｇ－１）能明显减轻缺血再灌损伤区超微结构的病理改变，显著提高大鼠心肌组织ＳＯＤ活性并减少ＭＤＡ的生成。结论：ＴＦＨ对大鼠心肌缺血再灌损伤的保护作用可能与提高自由基清除酶活性及抑制脂质过氧化反应有关。     

前列腺素E_1、川芎嗪合用对大鼠心肌缺血再灌注损伤的保护作用

目的观察前列腺素Ｅ１（３１２５μｇ·ｋｇ－１）与川芎嗪（２５ｍｇ·ｋｇ－１）合用对大鼠心肌缺血再灌注损伤的影响。方法麻醉大鼠冠脉结扎３０ｍｉｎ后，再灌６０ｍｉｎ诱发心律失常，硫代巴比妥酸法和分光光度法分别测定ＭＤＡ、ＳＯＤ及ＧＳＨ Ｐｘ，原子吸收光度法测定心肌细胞内Ｃａ２＋含量。结果两药小剂量合用的效果优于各药较大剂量单用。联合用药不仅更显著提高缺血再灌心肌ＳＯＤ、ＧＳＨ Ｐｘ活力（Ｐ＜００１），尚可显著降低ＭＤＡ、Ｃａ２＋及血清ＣＫ ＭＢ含量（Ｐ＜００１），防止缺血再灌室性心律失常的发生（Ｐ＜００１）。结论前列腺素Ｅ１与川芎嗪合用对心肌缺血再灌注损伤的保护作用有显著的协同作用。其作用与提高自由基清除酶活性、抑制脂质过氧化反应和防止心肌细胞内“钙超负荷”有关     

Effect of melatonin on production of hydroxyl radical and lactate dehydrogenase during hypoxia in rat cortical slices 1

目的：研究褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生成的影响．方法：通过水杨酸捕获法来观察缺氧再给氧中羟自由基含量的变化．脑片通以９１６％Ｎ２＋８４％Ｏ２造成缺氧．ＬＤＨ用细胞毒检测盒测定．结果：ＤＨＢＡ水平在缺氧及再给氧后显著升高;缺氧时给予褪黑激素可以浓度依赖性地降低再给氧１５ｍｉｎ时ＤＨＢＡ的含量,但对缺氧３０ｍｉｎ时ＤＨＢＡ的含量没有显著作用．ＬＤＨ的含量在缺氧后１ｈ内持续升高;褪黑激素可以显著降低缺氧后ＬＤＨ的释放．结论：褪黑激素降低大鼠缺氧后的损伤以及羟自由基的产生．     

乙酰香茶菜甲素抗心肌缺血再灌注损伤作用

用麻醉大鼠缺血４０ｍｉｎ，再灌注３０ｍｉｎ所致的心肌缺血再灌注损伤模型，观察了乙酰香茶莱甲素（ＤＡＡ－Ａ）对心肌缺血再灌注损伤的保护作用。ＤＡＡ－Ａ能提高缺血及再灌期左室收缩压（ＬｖＳＰ）及±ｄｐ／ｄｔｍａｘ，降低再灌注所致心律失常发生率，降低血浆中磷酸肌酸激酶（ＣＰＫ）、丙二醛（ＭＤＡ）、血栓素Ｂ２（ＴＸＢ２）的水平，缩小心肌梗塞面积。结果提示：ＤＡＡ－Ａ对心肌缺血再灌注损伤有明显保护作用，其机制与抗脂质过氧化损伤有关．     

褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生 …

目的 研究褪黑激素对大鼠大脑皮层脑片在缺氧后羟自由基及乳酸脱氢酶生成的影响。方法 通过水杨酸捕获法一观察缺氧再给氧中自由基含量的变化,脑片通以９１．６％,Ｎ２＋８．４％Ｏ２造成缺氧。ＬＤＨ用细胞毒检测盒测定。结果：ＤＨＢＡ水平在缺氧及再给氧后显著升高,缺氧时给予褪黑激素可以浓度依赖性地降低再给氧１５ｍｉｎ时ＤＨＢＡ的含量,但对缺氧３０ｍｉｎ时ＤＨＢＡ的含量没有显著作用,ＬＤＨ的含量在缺氧后１ｈ内持     

双乙酰香茶菜甲素抗离体大鼠工作心脏缺血再灌注损伤的作用

目的：观察双乙酰香茶菜甲素（ＤＡＡ－Ａ）对心肌缺血再灌注损伤的作用，方法：离体大鼠心脏停灌４０ｍｉｎ，再灌２５ｍｉｎ，造成心肌缺血再灌注损伤模型，结果：ＤＡＡ－Ａ０．１３，０．２５，０．５０ｍｍｏｌ．Ｌ＾－１对再灌注所致心功能低下有心脏保护作用，降低室颤发生率及乳酸脱氢酶（ＬＤＨ），丙二醛（ＭＤＡ）的生成量，ＤＡＡ－Ａ０．２５ｍｍｏｌ．Ｌ＾－１改善心肌超微结构，结论：ＤＡＡ－Ａ抗心肌缺血再灌注损伤     

芸香甙对脑缺血再灌损伤的保护作用

目的研究芸香甙（Ｒｕ）对脑缺血再灌损伤的保护作用。方法小鼠脑缺血再灌模型通过结扎双侧颈总动脉并尾部放血０．３ｍｌ，再灌后，记录异常神经症状和断头后张口喘气时间，测定脑组织中乳酸脱氢酶（ＬＤＨ）含量；利用４血管模型，大鼠前脑缺血３０ｍｉｎ后再灌注４０ｍｉｎ。取脑组织测定ＬＤＨ、过氧化物歧化酶（ＳＯＤ）、丙二醛（ＭＤＡ）、一氧化氮（ＮＯ）及脑水肿。结果Ｒｕ（５０，１００ｍｇ·ｋｇ－１，ｉｖ），显著改善小鼠脑缺血再灌损伤后的异常神经症状和抑制断头后张口喘气时间的缩短及脑组织中ＬＤＨ的减少。Ｒｕ显著抑制大鼠脑缺血再灌损伤所致的脑水肿形成和脑组织中ＬＤＨ、ＳＯＤ、ＭＤＡ及ＮＯ的变化。结论Ｒｕ对脑缺血再灌损伤有显著的保护作用，其机制与抗自由基和ＮＯ有关。     

双乙酰香茶菜甲素抗离体大鼠工作心脏缺血再灌注损伤的作用

目的：观察双乙酰香茶菜甲素（ＤＡＡＡ）对心肌缺血再灌注损伤的作用．方法：离体大鼠心脏停灌４０ｍｉｎ，再灌２５ｍｉｎ，造成心肌缺血再灌注损伤模型．结果：ＤＡＡＡ０１３，０２５，０５０ｍｍｏｌ·Ｌ－１对再灌注所致心功能低下有心脏保护作用，降低室颤发生率及乳酸脱氢酶（ＬＤＨ），丙二醛（ＭＤＡ）的生成量．ＤＡＡＡ０２５ｍｍｏｌ·Ｌ－１改善心肌超微结构．结论：ＤＡＡＡ抗心肌缺血再灌注损伤的作用与其抗脂质过氧化损伤有关．     

7-氯苄基四氢巴马汀对离体大鼠心肌缺血再灌损伤的保护作用

目的：研究７－氯苄基四氢巴马汀对离体大鼠心肌缺血再灌损伤的影响。方法：利用Ｌａｎｇｅｎｄｏｒｆ大鼠心脏，结扎冠状动脉前降支（ＬＡＤ），缺血１０ｍｉｎ后，再灌注２０ｍｉｎ，造成缺血再灌损伤模型。结果：７－氯苄基四氢巴马汀（７－ｃｈｌｏｒＢＴＨＰ）可明显减慢心率，消除再灌注引起的心室纤颤，明显缩短心律失常持续时间，并能抑制离体大鼠心肌缺血、复灌时磷酸肌酸激酶（ＣＰＫ）及乳酸脱氢酶（ＬＤＨ）释放增加。结论：７－ｃｈｌｏｒＢＴＨＰ具有抗离体大鼠再灌注心律失常作用，对缺血再灌注损伤心肌有保护作用，其作用机制可能与其减慢心率，减少缺血复灌时心肌酶释放有关。     

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.     

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.     

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.     

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.