Evoked phase synchronization between adjacent high-density electrodes in human scalp EEG: duration and time course related to behavior.

OBJECTIVE: Data from a previous event-related potential (ERP) study in visual-perceptual grouping [Nikolaev AR, van Leeuwen C. Flexibility in spatial and non-spatial feature grouping: an event-related potentials study. Brain Res Cogn Brain Res 2004;22:13-25] were re-analyzed to identify event-related dynamics of phase-synchronization. METHODS: In 20 Hz activity, uniform spreading of phase synchronization in closely spaced (approximately 2 cm) scalp electrodes appears and disappears spontaneously. The lengths of synchronized activity intervals and how they vary as a function of stimulus presentation were compared between task and control conditions. RESULTS: Synchronization reached a maximum in the task condition about 180 ms post-stimulus onset, coinciding with the peak N180 ERP marking the deployment of task-specific attention. Synchronized intervals were longer in the task than in the control condition. Long (above 80 ms) intervals occurred at a stable rate before and just after stimulus onset, but steeply decreased 200-400 ms afterwards. CONCLUSIONS: Perceptual tasks lead to longer synchronized intervals in early visual areas. Attention deployment resets the ongoing synchronization. Event-related activity, besides low-frequency ERP, consists of high-frequency short and long synchronized intervals corresponding to evoked bursts and ongoing oscillations, respectively. SIGNIFICANCE: High-density scalp recorded EEG revealed synchronization dynamics in a local, early visual area of cortex that can be interpreted as modulation of spontaneous ongoing task-related processes by attention.     

Serum lipoprotein (a) in renal transplant recipients receiving cyclosporin monotherapy

Coronary heart disease is more common in patients with chronicrenal failure and is a major cause of death after renal transplantation.Elevated serum lipoprotein (a) (Lp(a)) is a known risk factorfor coronary heart disease in the general population. We measured the serum concentration of Lp(a) in 58 renal transplantrecipients (40 male, 18 female) on cyclosporin monotherapy,and in 58 age- and sex-matched controls. Serum Lp(a) was significantlyelevated in the transplant patients with a median of 27.5 (range< 0.8–140.3) mg/dl compared to 7.6 (range <0.8–87.4)mg/dl in controls (P<0.001). Total serum cholesterol, low-densitylipoprotein cholesterol, and total triglyceride concentrationswere also significantly raised (P<0.001) in the transplantrecipients. The increased serum Lp(a) may contribute to the increased cardiovascularmorbidity associated with renal transplantation.     

Serum lipids and lipoproteins in patients treated with antiepileptic drugs

The concentration levels of serum lipids and lipoproteins were measured in three groups of children and adolescents treated with antiepileptic drugs: carbamazepine (14 patients), phenobarbital (20 patients), and valproic acid (20 patients). Patients treated with these drugs revealed significant changes in lipids and lipoproteins, but when the authors reevaluated the three groups of children 1 year after the end of treatment, a complete return to normal of all parameters was observed. These data demonstrate that the changes induced by these drugs are transient and reversible.     

绒毛膜促性腺激素与脂蛋白代谢关系之初探

作者研究了绝经前后妇女的绒毛膜促性腺激素（ｈＣＧ－β）与血脂、脂蛋白及载脂蛋白的变化，并通过大鼠动物模型观察高甘油三酯血症（ＨＴＧ）时的ｈＣＧ－β水平。结果发现绝经妇女血清ｈＣＧ－β含量较绝经前妇女显著升高（Ｐ＜０．００１），甘油三酯（ＴＧ）水平亦增高（Ｐ＜０．０５），而高密度脂蛋白胆固醇（ＨＤＬ－Ｃ）及ＨＤＬ－Ｃ／ＬＤＬ－Ｃ比率下降（Ｐ＜０．００１及Ｐ＜０．０１）；ＨＴＧ大鼠血清ｈＣＧ－β含量有上升趋势，且雄鼠ｈＣＧ－β含量显著高于对照组（Ｐ＜０．０５）。     

N-acetylcysteine and serum concentrations of lipoprotein(a).

A high plasma concentration of lipoprotein(a) [Lp(a)], a complex of low-density lipoprotein linked by disulphide bridges to apoprotein(a), is correlated with premature atherosclerosis. We determined whether the serum Lp(a) concentration could be decreased in vitro and in vivo by the reducing agent N-acetylcysteine (NAC), a drug used as a mucolytic agent, which acts by cleaving disulphide bonds. High concentrations of NAC (greater than or equal to 8 mg ml-1) resulted in dissociation of the Lp(a) antigen in vitro. However, the plasma level of Lp(a) was not changed by administration of NAC 1.2 g d-1 for 4 weeks in 7 subjects with a median Lp(a) concentration of 14.3 mg dl-1 (range 2.1-21.0 mg dl-1) or by doubling the dose to 2.4 g d-1 for a further 2 weeks. In 12 subjects with a high plasma level of Lp(a), median 87.0 mg dl-1 (range 42.0-201.6 mg dl-1), a small but significant decrease in Lp(a) concentration of 7% (P = 0.02) was observed after administration of NAC in a dose of 1.2 g d-1 for 6 weeks. These results indicate that NAC has only a limited capacity to reduce the concentration of Lp(a), which is not clinically significant.     

脑出血、脑血栓病发生与血胆固醇、甘油三脂及高密度脂蛋白水平的相关研究

目的：研究脑出血、脑血栓病的发生与血中胆固醇（TC）、甘油三脂（TG）及高密度脂蛋白（HCL）水平的关系。方法：采用试剂盒检测43名脑梗塞、42名脑出血患者血脂，并与对照组比较。结果：脑梗塞组TC、TG明显升高，HDL明显降低；脑出血组TC、TG亦明显升高，HDL明显降低。结论：血脂异常是脑血管病发病的重要因素之一。     

The effects of gemfibrozil upon the hypercoagulable state in dyslipidaemic patients with chronic renal failure

BACKGROUND.: The dyslipidaemia of chronic renal disease could contributeto a hypercoagulable state by activation of blood coagulationand/or impairment of fibrinolysis, thereby increasing cardiovasculardisease (CVD) risk. METHODS.: We measured the coagulation activation marker prothrombin fragmentF1 + 2 (F1 + 2), fibrinogen, plasminogen activator inhibitor-1 activity (PAI1), interleukin-6(IL6), insulin, lipids and lipoprotein(a)(Lp(a)), in 12 patients with chronic renal disease before andafter gemfibrozil. RESULTS.: Gemfibrozil significantly reduced triglycerides by 44% and increasedHDL-cholesterol by 31% without significant change in LDL cholesterol.Before treatment, patients had increased F1 +2, fibrinogen andIL6, but similar PAI1 compared with the controls, consistentwith a hypercoagulable and persistent inflammatory state. Followingtreatment, F 1 + 2 decreased to within the normal range andthis reduction correlated with the decrease in triglyceridesand inversely with the increase in HDL-cholesterol. A nonsignificantdecrease in fibrinogen was inversely correl ated with a significantincrease in albumin. However, Lp(a) and PAI1 activity significantlyincreased whilst insulin and IL6 were unchanged. CONCLUSIONS.: Gemfibrozil improved the uraemic dyslipidaemia and hypercoagulablestate by reduction in activation of blood coagulation, indirectlysuggesting a reduction in lipid-dependent extrinsic pathwayactivity which should contribute to reduced risk of throm bosisand CVD. Reduced fibrinogen and increased albumin are consistentwith a reduction in the acute phase response. Increased PAI1and Lp(a) could impair fibrinolysis and potentially increaseCVD risk, although the mechanism for these effects is uncertainbut does not appear related to cytokine or insulin mediatedmechanisms and requires further study. Large prospective studiesare required to determine if gemfibrozil can reduce CVD eventsin uraemia.     

小檗胺和黑豆果油预防大鼠血脂紊乱作用的研究

本实验证明了无论是单用小檗胺，黑豆果油或两者合用均能预防大鼠血中胆固醇，甘油三酯，低密度脂蛋白含量的升高，复方用药不能增强其降血脂效果；复方大剂量组与小剂量组存在一定的量效关系；单方或复方用药预防血脂升高作用均强于烟酸肌醇酯。     

大鼠血清ApoA-I、LDL的分离和纯化

用沉淀法分离大鼠血清高密度脂蛋白(HDL),SephadexG—200层析纯化;将脱脂的HDL(ApoHDL)通过SephadexG—200柱层析得到单一的载脂蛋白A-I(ApoA-1)。SDS-聚丙烯酰胺凝胶电泳(SDS—PAGE)测定该ApoA-Ⅰ的表观分子量为27000道尔顿,其免疫学特征及化学组成分析结果与文献报道一致。同时用超速离心法分离制备出纯化的大鼠血清低密度脂蛋白(LDL)。     

Serum Lipoprotein (a) Concentration in Patients with Nephrotic Syndrome and Its Clinical Implication

Serum lipoprotein(a) [Lp(a)] concentration was determined in 42 patients with primary nephrotic syndrome (NS) and the relationships between Lp (a) and plasma lipids, apolipoproteins, serum creatinine (Scr), albumin, urinary proteins (Upro) were also analyzed. The results showed that: (1) serum Lp(a) concentrations in the patients with NS were higher than those in healthy controls;(2) the levels of serum Lp (a) were correlated positively with total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), apolipoprotein B (Apo-B), Upros (Upro). It is concluded that the NS patients had the potential risk of suffering from coronary artery disease, glomerular sclerosis and thrombosis. The remission of NS may partially decrease the serum Lp(a) levels. Further studies are needed to explore the prevention and treatment of dislipedemia in patients with NS.