Permeability of pure lipid bilayers to melatonin

Abstract: Melatonin, the chief hormone of the pineal gland, has been reported to interact with a variety of different cells. This ubiquitously acting hormone has been found to interact with protein receptors both at the cell membrane and in the nucleus. Moreover, melatonin was recently shown to be a very potent hydroxyl radical scavenger. The present work focuses on the interaction of melatonin with pure lipid bilayers. It is shown that melatonin can cross multilamellar lipid vesicles, which are used here as model systems for the lipid phase of biological membranes. Thus, the data prove that melatonin can easily pass through the cell membrane and bath every part of the cell, as previously suggested in the literature. Melatonin lipid association constant was calculated based on the change of the hormone fluorescence intensity due to its penetration into the hydrophobic lipid phase. Though melatonin was recently shown to be highly soluble in aqueous media, its lipid association constant is rather high, indicating that the biological action of the hormone is likely to be at the membrane level, either via its interaction with membrane receptors, and/or as a lipoperoxidation radical scavenger.     

豆渣纤维的降脂作用及对血液流变学影响的研究

以ＳＤ大鼠为对象，研究了豆渣纤维对高胆固醇膳动物脂质代谢和血流变性的影响，并与果胶和纯纤维素进行比较，结果表明：８周实验后，豆渣与果胶组动物的血清总胆固醇（ＴＣ）和低密度脂蛋白胆固醇（ＬＤＬ－Ｃ）显著降低，但豆渣组的血脂水平比果胶组更低（Ｐ＜０．０５）。而纯纤维素组未显出降脂作用。各组大鼠的甘油三醋（ＴＧ）和高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）也无明显变化。实验同时表明，６％的豆渣纤维与果胶均可使高脂大鼠的血粘度及血小板聚集率降低（Ｐ＜０．０５），且前者优于后者。相关分析显示，血脂与血流变学指标间存在显著相关性（Ｐ＜０．０５），其中ＴＣ与ＬＤＬ－Ｃ是影响血流变性的重要因素。６％的以上各种纤维摄入量均不影响大鼠的摄食量与生长。     

MPTP对鼠肝脂质过氧化作用的影响

本文报道给C57小鼠腹腔注射不同剂量1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)后,发现组3(MPTP35 mg/kg,每天一次,共7天)鼠肝匀浆、线粒体和微粒体的膜丙二醛含量明显增加,与对照组相比分别增加70.5%,67%和51.4%(P<0.01),而组1(MPTP 35mg/kg,每4小时一次,共3次)和组2(MPTP35mg/kg,每天一次,共4天)鼠肝丙二醛含量与对照组相近。结果表明MPTP有明显地促进鼠肝脂质过氧化的作用,并与其剂量有关。     

地尔硫对冠心病的抗氧化作用

目的：观察地尔硫对冠心病病人的抗脂质过氧化及抗氧自由基作用。方法：冠心病病人３０例为治疗组（男性２１例，女性９例，年龄５８±ｓ６ａ），给予地尔硫３０ｍｇ，ｐｏ，ｔｉｄ，共４ｗｋ。健康人组３０例（男性１８例，女性１２例，年龄５８±９ａ）。结果：治疗组在给药前较健康人组的血清ｏｘＬＤＬ，ＬＰＯ，ＳＣＬ，ＬＣＬ值显著升高，Ｐ＜０．０１，ＧＳＨ－Ｐｘ显著降低，Ｐ＜０．０１，ＳＯＤ活力两者无明显差异，Ｐ＞０．０５。治疗组用药后与用药前相比ｏｘＬＤＬ，ＬＰＯ，ＳＣＬ，ＬＣＬ值显著下降，Ｐ＜０．０１或＜０．０５，ＧＳＨ－Ｐｘ显著升高，Ｐ＜０．０１，治疗组治疗后与健康人组相比，除ＬＣＬ外，其他指标皆无明显差异，Ｐ＞０．０５。结论：地尔硫是一良好的抗氧化剂。     

缺氧对大鼠大脑皮层细胞过氧化物及巯基含量影响

采用荧光分光光度法，检测缺氧大鼠的大脑皮层细胞脂质过氧化物和巯基含量的变化及金属硫蛋白对神经细胞的保护作用。结果表明：缺氧组细胞中脂质过氧化物的含量明显高于对照组（Ｐ＜０．０１）；巯基含量显著低于对照组（Ｐ＜０．０１）；金属硫蛋白能抑制脂质过氧化物的生成，使巯基含量升高。结果提示：缺氧可引发大脑皮层细胞脂质过氧化，抗氧化剂金属硫蛋白对细胞脂质过氧化损伤有一定的保护作用。     

中药肉苁蓉及其同属生药对免疫功能及酯质过氧化的作用

肉苁蓉为我国著名补益中药。以不同种的肉苁蓉的乙酸乙酯提取物和水提取物进行免疫药理试验，以不同种的水提物进行对脂质过氧化影响的试验。结果表明不同种肉苁蓉的提取物有强度不同的增强免疫功能和抑制脂质过氧化作用。     

三七中人参三醇甙对大鼠离体心脏缺血再灌注损伤及心律失常的保护作用

三七中人参三醇甙(PTS)5,50μg·ml~(-1)灌流对离体大鼠Langendorff心脏缺血再灌注所致心律失常具有明显的保护作用,可降低室颤发生率,并可保护心肌组织中超氧化物歧化酶的降低,PTS 50μg·ml~(-1)还可抑制心肌丙二醛的产生,对缺血再灌注所致心肌乳酸脱氩酶和磷酸肌酸激酶的漏出亦有明显的抑制作用。     

冠心病不同临床类型患者血浆、血小板脂质过氧化损伤与TXA_2/PGI_2平衡的研究

作者观察98例正常人和109例不同临床类型冠心病人血浆、血小板LPO、SOD,SeGSHP_x,RBC—SOD及血浆TXB_2、6-keto-PGF_(1α)的变化,发现各型冠心病组均有LPO、PL—LPO、TxB_2、TxB_2/6-keto-PGF_(1α)比值明显升高,6-keto-PGF_(1α),SOD、PLSOD、RBC-SOD,SOD/LPO及SeGSHPX/LPO比值明显降低。但各型程度不同,以急性心肌梗塞和不稳定性心绞痛改变突出。血浆LPO与6-keto-PGF_(1α)呈显著负相关。提示脂质过氧化损伤与TXA_2/PGI_2平衡密切相关。认为SOD/LPO、SeGSHPx/LPO,TXB_2/6-keto-PGF_(1α)比值在冠心病诊断中是重要有意义的指标,血小板SOD/LPO比值能更敏感地反映冠心病人氧化与抗氧化能力的平衡状态。     

Effect of oxygen aeroions on platelet aggregation and lipid peroxidation in health and peritonitis

In patients with peritonitis, the biological effects of oxygen aeroions reflect the interplay between molecular and cellular effects manifesting themselves in the inhibition of lipid peroxidation, increased antioxidizing potential of blood plasma, and decreased aggregating activity of platelets. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 9, pp. 283–285, September, 1997