氨基胍对去卵巢大鼠主动脉晚期糖化终末产物及血脂的影响

将 6月龄雌性SD大鼠随机分为假手术组 (sham)、去卵巢组 (OVX)和去卵巢 +氨基胍组 (OVX +AG)。去除双侧卵巢 2周后用氨基胍治疗 13周。禁食 2 4h ,放血处死动物 ,取血和主动脉 ,分别测定主动脉AGEs、血脂和血清过氧化物含量。结果表明 ,与假手术组比较 ,去卵巢组主动脉AGEs、甘油三脂 (TG)、氧化低密度脂蛋白 (OX LDL)、丙二醛 (MDA)均明显升高 (分别为P <0 0 1,P <0 0 5 ,P <0 0 5和P <0 0 1) ;高密度脂蛋白 胆固醇 (HDL C)、载脂蛋白AⅠ (apo AⅠ )和超氧化物歧化酶 (SOD)活性均显著降低 (均P <0 0 1)。氨基胍组与病理组比较 ,主动脉AGEs、血清TG、MDA和OX LDL均明显降低 (分别为P <0 0 1,P <0 0 5、P <0 0 5和P <0 0 1) ;HDL C、apo AⅠ和SOD活性均显著升高 (均P <0 0 1)。提示氨基胍通过降低去卵巢大鼠主动脉AGEs含量 ,降低大鼠血清OX LDL和TG水平 ,升高HDL C、apo AⅠ水平和SOD活性 ,发挥其对心血管的保护作用     

H_2O_2和NO对滑膜成纤维细胞增殖反应的影响

采用~3H-TdR掺入法和MTT比色法研究过氧化氢(H_2O_2)和一氧化氮(NO)对兔滑膜成纤维细胞(SF)增殖反应的影响。结果表明,在使用亚适SF浓度(5×10~7细胞/L)时,~3H-TdR掺入法和MTT比色法检测结果一致。H_2O_22和亚硝基铁氰化钠(NO供体)在低浓度时促进SF增殖反应,而在高浓度时抑制其增殖反应,提示H_2O_2和NO对SF增殖反应具有双向调节作用。     

Channels in planar bilayers made from commercially available lipids

Planar bilayer membranes were made from commercially available lipids. With various lipids, originating from biological sources, such as egg yolk phosphatidylcholine, soybean phosphatidylcholine or bovine brain phosphatidylserine, spontaneously fluctuating channels could be observed. Spontaneous channel activity could not be observed in planar bilayers made from synthetic lipids, such as 1,2 diphytanoyl 3-sn-phosphatidylcholine. It is concluded that the observed channels are due to proteolipids, being present as impurities in the lipid material.     

Studies on fine structure and location of lipids in quick-freeze replicas of atherosclerotic aorta of WHHL rabbits

Summary The fine structure of intracellular and extracellular lipids in the atherosclerotic aorta of Watanabe-heritable hyperlipidemic (WHHL) rabbits was demonstrated by a quick-freeze etching technique. Many lipid droplets, with and without a membrane, were observed in the foam cells. Membrane-free droplets were observed as onionlike structure with a concentric lamellar structure surrounded by 10 nm filaments. Droplets surrounded by a limited membrane probably correspond to lipid-laden lysosomes.In the extracellular connective tissue space, marked accumulation of lipids with a vesicular structure was seen among collagen fibers. The appearance of these lipids was similar to that of lipids in lysosomes of foam cells.     

Rapid microassays of phagocytosis, bacterial killing, superoxide and hydrogen peroxide production by human neutrophils in vitro

Simple, rapid microassays for simultaneous measurement of phagocytosis, bacterial killing, superoxide and hydrogen peroxide production by human neutrophils in vitro are described. All assays employ 96-well flat bottom tissue culture plates which were incubated on a microtitre plate shaker at 37 degrees C. The separate evaluation of ingestion and intracellular killing of E. coli and S. aureus was based on the incorporation of [3H]uridine into viable extracellular bacteria. There was good correlation between plate counts of viable bacteria and amount of radiolabel incorporation. Phagocytosis and killing can be measured in a maximum of 100 microliter reaction mixture, requiring only 2.5 X 10(5) neutrophils per test and the assay is complete within 60 min. Assay of superoxide production by stimulated neutrophils was based on superoxide-dependent reduction of ferricytochrome c as measured spectrophotometrically at 550 nm in wells of tissue culture plates containing 150 microliter of reaction mixture. The assay requires only 1.25 X 10(5) neutrophils per test and is complete within 50 min. Quantitation of hydrogen peroxide was based on horseradish peroxidase-dependent oxidation of phenol red. The technique is as for superoxide detection except that the reaction must be terminated by the addition of 1 M NaOH at the desired time intervals. None of the assays require sampling during the incubation period. The principal advantages of the described techniques are increased simplicity and speed, requirement of low numbers of neutrophils and applicability to analysis of large number of samples in parallel.     

Possible involvement of nitric oxide in the pathogenesis of experimental convulsions of various genesis

The content of nitric oxide in convulsions of different genesis is assessed by measuring the formation of paramagnetic mononitrosyl iron complexes with diethylthiocarbamate by electron paramagnetic resonance. A 3- to 4-fold increase in the content of these complexes is found in the brain of rats with thiosemicarbazide- or N-methyl-DL-aspartate-induced seizures in comparison with control animals. A similar increase in the brain NO content was observed in maximum electrical stimulation of metrazol-induced convulsions. These changes were accompanied by elevation of secondary lipid peroxidation products. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 125, No. 1, pp. 26–29, January, 1998     

Effects of cilostazol on lipid and fatty acid metabolism

Abstract Cilostazol is a selective inhibitor of phosphodiesterase III with anti-platelet-aggregatory and vasodilating properties. Randomised, double-blind, placebo-controlled trials in 2702 patients with intermittent claudication demonstrated that cilostazol significantly increased walking distances compared with placebo. Furthermore, the agent has beneficial effects on the serum lipid profile and fatty acid composition in plasma. Consequently, cilostazol may be useful to prevent atherosclerosis from progressing by ameliorating lipid and fatty acid metabolism.     

萝摩甙抗自由基损伤作用的实验研究

目的:探讨萝摩甙对自由基所致脑损伤的神经元保护作用及机制。方法:复制脑缺血模型及H₂O₂诱导神经元损伤模型,分别测定大鼠脑组织、培养神经元中的丙二醛(MDA)含量以及培养神经元中的乳酸脱氢酶(LDH)漏出率、DNA断裂率和羟自由基清除率,观察萝摩甙对损伤神经元的保护作用。结果:萝摩甙可明显降低脑缺血造成的MDA的升高,亦可明显降低H₂O₂对神经元造成的LDH漏出率、DNA断裂率增加和丙二醛含量的升高,而且随着萝摩甙浓度的升高羟自由基清除率明显升高。结论:萝摩甙可通过清除自由基来保护神经元。