Reactive oxygen species and human spermatozoa: physiology and pathology

The role of reactive oxygen species (ROS) in the pathophysiology of human sperm function has been emphasized in recent years. ROS production in semen has been associated with loss of sperm motility, decreased capacity for sperm–oocyte fusion and loss of fertility. There is a current presumption that the most prolific source of ROS in sperm suspensions is an NADPH oxidase located in leukocytes or in spermatozoa which produces superoxide which is further converted to peroxide by the action of superoxide dismutase. Hydrogen peroxide has been recognized as the most toxic oxidizing species for human spermatozoa, which are very sensitive to lipid peroxidation owing to the high content of polyunsaturated fatty acids in their plasma membrane, though this is not the sole mechanism by which sperm function might be impaired by ROS. Although the excessive production of ROS is detrimental to human spermatozoa, there is a growing body of evidence which suggests that ROS are also involved in the physiological control of some sperm functions. This review focuses on the nature and source of the ROS generated by human spermataozoa as well as their operational mechanisms and their effects, which may be detrimental or beneficial.     

低胆红素血症对机体抗氧化能力和脂质过氧化的影响及VitE的干预效果

目的 :探讨低胆红素血症对机体抗氧化能力和脂质过氧化的不良影响并观察VitE的干预效果。方法 :从体检健康人群中有意选择 4 5例胆红素水平偏高者 (≥ 15 μmol/L)和 4 0例胆红素水平偏低者 (≤ 9μmol/L)作为研究对象 ,抽空腹静脉血检测血清总抗氧化能力 (T -AOC) ,丙二醛 (MDA)及血浆氧化修饰低密度脂蛋白(Ox -LDL) ,并给低胆红素组每人每天口服VitE 10 0mg ,连续 2周 ,复测上述指标。结果 :与高胆红素组比 ,低胆红素组T -AOC明显降低 (P <0 .0 1) ,而MDA和Ox -LDL明显升高 (P <0 .0 5和P <0 .0 1) ,但低胆红素组补充VitE干预后 ,T -AOC显著升高 ,而MDA和Ox -LDL显著降低 (均P <0 .0 1) ,分别达到甚至超过了高胆红素组的相应水平。结论 :低胆红素血症可显著降低机体抗氧化能力 ,促进脂质过氧化 ,但这一不良影响可以通过补充VitE得到有效纠正。     

Hepatic reticuloendothelial function during parenteral nutrition including an MCT/LCT or LCT emulsion after liver transplantation – a double-blind study

It has been demonstrated that total parenteral nutrition (TPN) modulates the function of the hepatic reticuloendothelial system (RES). The objective of this study was to evaluate the impact of two different TPN lipid emulsions on the recovery of allograft RES function after orthotopic liver transplantation (OLTx). In a prospective, double-blind study, OLTx patients were randomly assigned to two treatment groups. Group I ( n=13) received a TPN regimen that included long-chain triglycerides (LCT). Group II ( n=9) received a TPN regimen that included a fat emulsion consisting of both medium-chain triglycerides (MCT) and LCT. At baseline, i.e., on days 2 or 3 after OLTx ( t1), before lipids for TPN were started, hepatic RES function was determined using the human serum albumin millimicrosphere technique (K-value, 1/min). A second measurement ( t2) was obtained after 7 days of TPN, including one of the study's two fat emulsions. The mean (+/- SD) K-value (1/min) was 0.48+/-0.16 in the LCT group and 0.55+/-0.28 in the MCT/LCT group at t1, and it improved to 0.62+/-0.21 in the LCT group and to 0.86+/-0.32 in the MCT/LCT group at t2. RES function recovery was significantly better in the MCT/LCT group ( P< or = 0.05). MCT/LCT emulsion appears to be the TPN fat emulsion of choice after OLTx as it seems to have less impact on hepatic RES recovery.     

脂肪抽吸术对胰岛素敏感性及脂质代谢的影响

目的了解脂肪抽吸术对胰岛素抵抗与脂质代谢的影响,并探讨其临床意义。方法对20例接受腹部脂肪抽吸术者术前及术后2个月的血清三酰甘油、总胆固醇、高密度脂蛋白胆固醇、低密度脂蛋白胆固醇,胰岛素敏感性进行测量并进行比较。结果术后与脂肪抽吸术前比较,术后胰岛素敏感性增强（P〈0.01）,血清总胆固醇与低密度脂蛋白胆固醇水平下降。结论腹部脂肪抽吸术在去除大量皮下脂肪的同时,对胰岛素抵抗、脂质代谢等心脑血管危险因素也有非常有益的影响。     

Dynamics of lipid adsorption at the electrified water∣1,2-dichloroethane interface

A recently introduced setup to measure the dynamic interfacial tension of expanding drops was used to compare the adsorption behaviour of a series of lipids at the electrified water∣dichloroethane interface. Phospholipids with saturated carbon chains of different length (DMPC, DPPC, DSPC, DAPC, DBPC), an unsaturated phospholipid (DOPC) and an ethanolamine (DSPE) were compared. It was found that the adsorption decreases with increasing chain length. Also, the increase of the flow rate reduces the degree of adsorption effectively. On the timescale of the experiments, the DSPE, DAPC and DBPC adsorption showed no potential dependence, whereas the adsorption of DOPC was stronger than that of the saturated lipids. Adsorption was modelled using the Langmuir adsorption isotherm; the potential dependence of adsorption is discussed.     

Investigations of a novel ferrocene-containing lipid by cyclic voltammetry and cryogenic transmission electron microscopy

A novel chiral redox-active ferrocene compound (FcVI) with amphiphilic properties has been synthesized. Cryogenic Transmission Electron Microscopy (cryo-TEM) has been used to estimate the shape and size of the FcVI aggregates in solution. Uni- and multi-lamellar vesicles (between 40 and 300 nm in diameter) were observed in water. Large particles (of more than 1 μm in diameter) with a hexagonal fine structure were found in 50 mM aqueous Na₂SO₄ solution. Sonication transformed the latter into ‘rosette’-like structures. Cyclic voltammetry has been employed to investigate the electrochemical properties of FcVI. The amphiphile adsorbed on graphite electrodes and a reversible electrochemical behaviour, characteristic of ferrocene, was observed with redox potentials between 330 and 350 mV.     

高龄初产妊高征孕妇过氧化反应的研究

目的：探讨高龄初产妊高征孕妇体内过氧化反应。方法：测定正常初产妇、妊高征孕妇妊娠晚期母血过氧化脂质（LPO）、超氧化物歧化酶（DOD）的含量。结果：1．高龄初产妇母血LPO较非高龄初产妇明显升高，SOD明显下降，P＜0．05。孕妇年龄与母血LPO呈明显正相关，与SOD呈明显负相关，P均＜0．05。2．妊高征孕妇LPO较正常孕妇显著增高，SOD显著下降，P＜0．05，并随病情加重LPO水平升高、SOD水平下降更为显著，P＜0．05。3．高龄初产妊高征孕妇母血LPO含量较非高龄初产妊高征孕妇明显增高，P＜0．05，而SOD则无显著变化，P＞0．05。4.妊高征孕妇胎儿宫内生长发育迟缓（IUGR）发生率较正常孕妇显著升高，P＜0．025，各组脐血清LPO、SOD含量无显著差异，P＜0．05。结论：高龄初产妊高征孕妇体内过氧化作用明显增强，LPO水平的升高可能为高龄初产妇妊高征发生率及IUGR发生率增加的原因之一。     

镉对肾脏的毒作用

雄性Ｗｉｓｔａｒ大鼠２４只，随机等分为４组，皮下注射不同剂量的ＣｄＭＴ。结果显示镉接触组尿钙和尿蛋白都高于对照组；肾皮质钠泵和钙泵活性低于对照组，体外试验也显示镉能抑制钙泵活性，ＧＳＨ和半胱氨酸对这种抑制有保护作用；肾皮质ＧＳＨ含量低于对照组，ＭＤＡ含量则高于对照组，但肝脏的这两个指标无变化；高剂量组ｃＡＭＰ／ｃＧＭＰ的比值低于对照组。提示脂质过氧化和钙代谢障碍是镉引起肾损害的机理之一。     

Lipid peroxidation in several brain regions during development of post-stress depressions in rats with different strategies of adaptive behavior

Lipid peroxidation in the brain cortex, striatum, hippocampus, and hypothalamus of rats of the KLA and KHA lines which were distinguished by their strategies of adaptive behavior was investigated following emotional-painful stress. Significant long-term changes in lipid peroxidation were shown to occur in the brain. These had a phase character and depended on the behavioral characteristics of the animals. The investigated brain regions were characterized by different reactions of lipid peroxidation to the stress. The induced depressive-like states (on the 21st day after the stress) in rats of the KLA and KHA lines were distinguished by the largest changes in lipid peroxidation in the striatum and hypothalamus and in the striatum and hippocampus, respectively. One could conclude on the basis of these results that both identical and different mechanisms of formation and development of depression existed in the animals with different behavioral strategies.