大鼠弥漫性脑损伤不同脑部位不同时相的脂质过氧化反应

利用Ｍａｒｍａｒｏｕ氏脑损伤动物模型,测定大鼠脑损伤后不同时间和部位的丙二醛（ＭＤＡ）含量。结果示：损伤后１ｈ,额叶、顶叶、脑干等处的ＭＤＡ水平分别比对照组高出３６７％,４１８％和３５１％（Ｐ＜０．０１）,并持续增高,伤后４ｈ达高峰后缓慢下降,伤后２４ｈ仍明显高于对照组。纹状体、颞叶等处伤后１ｈ的ＭＤＡ水平升高较上述部位稍低,而分别较对照组升高１６９％和１３３％（Ｐ＜０．０１）,伤后４ｈ虽仍持续升高,但不超过３５％。提示在大鼠弥漫性脑损伤后短期内即有自由基生成,几乎波及脑内各个部位,但程度不一。     

Reactive oxidant species in piriform cortex extracellular fluid during seizures induced by systemic kainic acid in rats

Kainic acid (KA) administered systemically to rats produces seizures and brain damage. We measured an increase in reactive oxidant species (ROS) during KA-induced seizures in the extracellular fluid (ECF) of the piriform cortex, a brain region known to be subsequently damaged. Intracerebral microdialysis samples were collected and assayed for isoluminol-dependent chemiluminescence before and after injection of KA (16 mg/kg, ip). Hydrogen peroxide (H₂O₂) concentrations were calculated from catalase-sensitive chemiluminescence, the difference between total and catalase-resistant chemiluminescence. During generalized tonic-clonic seizures, both total and catalase-resistant chemiluminescence increased significantly in samples from brain ECF. Catalase-resistant chemiluminescence, most likely produced by ascorbic acid, increased for a full hour during sustained seizure activity. H₂O₂ concentrations showed a trend towards elevation during seizures. Increased ROS suggest that oxidative stress occurs in brain ECF during sustained seizure activity.     

Cells defective in sphingolipids biosynthesis express low amounts of muscle nicotinic acetylcholine receptor

The properties of the nicotinic acetylcholine receptor (AChR) are modulated by its lipid microenvironment. Studies of such modulation are hampered by the cell's homeostatic mechanisms that impede sustained modification of membrane lipid composition. We have devised a novel strategy to circumvent this problem and study the effect of changes in plasma membrane lipid composition on the functional properties of AChR. This approach is based on the stable transfection of AChR subunit cDNAs into cells defective in a specific lipid metabolic pathway. In the present work we illustrate this new strategy with the successful transfection of a temperature-sensitive Chinese hamster ovary (CHO) cell line, SPB-1, with the genes corresponding to the four adult mouse AChR subunits. The new clone, SPB-1/SPH, carries a mutation of the gene coding for serine palmitoyl transferase, the enzyme that catalyses the first step in sphingomyelin (Sph) biosynthesis. This defect causes a decrease of Sph de novo synthesis at non-permissive temperatures. The IC50 for inhibition of alpha-BTX binding with the agonist carbamoylcholine exhibited values of 3.6 and 2.7 microm in the wild-type and Sph-deficient cell lines, respectively. The corresponding IC50 values for the competitive antagonist D-tubocurarine (D-TC) were 2.8 and 3.4 microm, respectively. No differences in single-channel properties were observed between wild-type and mutant cell lines grown at the non-permissive, lipid defect-expressing temperature using the patch-clamp technique. Both cells exhibited two open times with mean values of 0.35 +/- 0.05 and 1.78 +/- 0.2 ms at 12 degrees C. Taken together, these results suggest that the AChR is expressed as the complete heteroligomer. However, only 10-20% of the total AChR synthesized reached the surface membrane in the mutant cell line and exhibited a higher metabolic turnover, with a half-life about 50% shorter than the wild-type cells. When control CHO-K1/A5 cells were treated with fumonisin B1, an inhibitor of sphingosine (sphinganine) N-acetyltransferase (ceramide synthase), a 45.5% decrease in cell surface AChR expression was observed. The results suggest that sphingomyelin deficiency conditions AChR targeting to the plasma membrane.     

Peripheral total parenteral nutrition employing a lipid emulsion (Intralipid): complications encountered in pediatric patients.

The clinical records of 180 pediatric patients who received Intralipid via peripheral veins at a single institution (1964-1977) were retrospectively analyzed, with particular reference to the complications of this form of therapy. Intralipid was used in a dose range of 2--4 g/kg/day in order to supply 40% of the daily calorie requirements. The patients were neonates, infants, children, and adolescents with a wide range of clinical diagnoses. Local complications associated with Intralipid therapy were minimal. Transient elevations in serum enzyme levels (SGOT, SGPT, and LDH) were observed in 4% of patients, but all of these returned to the normal range after cessation of therapy. Ten patients had histologic evidence of cholestasis, the significance of which is discussed. The lipid emulsion was employed in patients with preexisting hyperbilirubinemia with concomitant resolution of jaundice. Intralipid was administered to patients with known severe thrombocytopenia (secondary to sepsis or myelosuppression) with return of the platelet counts to normal levels during the course of infusion therapy. The use of Intralipid in patients with established sepsis did not delay its response to conventional surgical or antibiotic therapy. There were no instances of the "overloading" syndrome observed.     

Cytotoxic Effect of Brain Macrophages on Developing

Brain macrophages are transiently present in different regions of the central nervous system during development or in the course of tissue remodelling following various types of injuries. To investigate the influence of these phagocytes on neuronal growth and survival, brain macrophages stemming from the cerebral cortex of rat embryos were added to neuronal primary cultures. A neurotoxic effect of brain macrophages was demonstrated by the reduction of the number of neurons bearing neurites within two days of contact between the two cell types. Neuronal death and phagocytosis were also directly observed in video recordings of living cultures. This toxicity involved the production by brain macrophages of reactive oxygen intermediates, as shown by the protective effect of catalase, a scavenger of H2O2. In addition, the respiratory bursts of brain macrophages were stimulated in the presence of neurons. These results suggest that brain macrophages could favour the appearance of neuroregressive events which occur either during neurogenesis or in neurodegenerative diseases, implying intracerebral recruitment of mononuclear phagocytes.     

Permeability changes of Ehrlich mouse ascites tumor cells induced by a cytotoxin from Pseudomonas aeruginosa

Summary Ehrlich ascites tumor cells from mice were damaged during in vitro incubation with a cytotoxin from Pseudomonas aeruginosa at concentrations of>1 g/ml. After a short time the cells started to lose potassium whereas their sodium content increased. When the protein concentration of the incubation medium was adjusted to the protein concentration inside the cells, swelling and release of glucose-6-phosphate dehydrogenase was avoided. However, lysis of the cells still took place.Preincubation of cells with tetrodotoxin, 4-aminopyridine or tetraethylammonium did not influence damage to the cells. The cells showed a steep increase in toxin response between 17° and 27°C ranging from insensitivity to full sensitivity.An increase in electrical conductance was measured during incubation of cholesterol bilayer membranes with a cytotoxin concentration of 1 g/ml. The conductance was increased by a factor of ten within 30 min at 25°C which indicates the involvement of membrane lipids in the cytotoxin action.Part of this study has been presented at the Joint Meeting of the Scandinavian and German Pharmacological Societies, Lübeck (Grieshaber and Lutz 1980)     

半夏厚朴汤醇提物对大鼠慢性抑郁模型的影响

目的 :研究半夏厚朴汤醇提物对大鼠慢性抑郁模型 (CMS)的影响 ,探索其抗抑郁机制。方法 :以 1%蔗糖水摄入量作为指标 ,慢性给予各种低强度复合刺激 ,造成大鼠慢性抑郁模型。按试剂盒酶法测定血脂 ;采用乳酸脱氢酶 (LDH)释放法测定脾细胞内自然杀伤细胞活性 ;采用邻苯三酚自氧化法测定红细胞内超氧化物岐化酶活性 ;按试剂盒显色法测定血清和组织中一氧化氮合酶活性 ;采用硫代巴比妥酸法测定心脏中丙二醛含量。结果 :在大鼠CMS模型中半夏厚朴汤醇提物可增加动物蔗糖摄入量 ;增加其脾脏自然杀伤细胞活性 ;升高血清中高密度脂蛋白 (HDL C)水平 (P<0 .0 5 ) ,降低甘油三酯水平 (P<0 .0 0 1) ;降低血红细胞内超氧化物岐化酶活性及血清和肝组织中一氧化氮合酶活性 ;同时抑制组织中脂质过氧化程度 ,降低心肌组织中丙二醛含量。结论 :半夏厚朴汤醇提物通过多途径而达到抗抑郁作用。     

磁极化生物平衡离子吸附疗法治疗老年人心脑血管病危险因素的临床研究

目的 探讨磁极化生物平衡离子吸附降脂降粘疗法(也称之为洗血疗法)对老年心脑血管病危险因素的临床疗效。方法 应用磁极化生物平衡离子吸附疗法对22例老年患有心脑血管病危险因素的患者进行治疗,并对临床各项指标进行对照比较。结果 22例患者治疗前后的血流变学指标、血脂等均有明显改善。治疗前患者的TCHO(胆固醇)、TG(甘油三酯)分别为(6.21±1.14)mmol/L和(6.78±5.13)mmol/L;治疗后分别为(4.36±0.99)mmol/L和(2.41±2.10)mmol/L,P<0.05,均显著降低。治疗前患者的HCT(红细胞压积)、PFC(纤维蛋白)、NP(血浆粘度)、NR(全血粘度)、VAI(细胞聚集指数)分别为(0.441±0.042)V、(4.11±1.78)g/L、(3.86±1.98)mpa.s、(5.68±0.79)mpa.s和0.89土0.23;治疗后分别为(0.344±0,061)V、(2.21±1.12)g/L、(1.49±0.40)mpa.s、(3.21±0.56)mpa.s和0.40±0.15,治疗前后对照比较,P<0.02。结论本方法对老年人心脑血管病危险因素的治疗是有效的。     

过氧化氢对豚鼠耳蜗功能及形态的影响

目的 在体观察过氧化氢(H2O2)对豚鼠耳蜗功能及形态的影响。方法 实验动物分为4组，分别灌流人工外淋巴液(artificial perilymph,APL)，50μMH2O2，100μMH2O2和200μMH2O2(H2O2均溶于APL中)，并用Pl和H033342双染色方法观察H2O2引起的内耳细胞损伤情况。结果 所有H2O2灌流组复合动作电位((CAP)阈移和耳蜗微音电位(CM)幅度变化与人工外淋巴液组比较差异有显著性，且各H2O2组的变化呈现出浓度依赖性；Pl和H033342双染色方法发现外毛细胞是H2O2攻击的主要靶细胞，而Hensen细胞未见任何损伤痕迹。结论 H2O2可导致耳蜗功能下降及耳蜗毛细胞损伤：Hensen细胞较毛细胞可能具有更强的抗氧化能力。