Glucocorticoid regulation of eicosanoid production by glial cells under basal and stimulated conditions

We measured the production of two eicosanoids, prostaglandin E₂ and thromboxane-B₂, by rat glial cell cultures under basal conditions, following stimulation with phorbol-12-myristate-13-acetate and the bacterial endotoxin lipopolysaccharide, and following treatment with synthetic glucocorticoids. Stimulation of rat glial cells in culture with either phorbol-12-myristate-13-acetate or lipopolysaccharide caused a 1.5–5.0-fold increase in prostaglandin E₂ production, but did not affect thromboxane production. Pretreatment of the cultures with dexamethasone markedly inhibited the stimulated production of prostaglandin E₂ but had only a modest effect on basal production. Dexamethasone did not affect the activity of the enzyme protein kinase C, a putative regulator of eicosanoid synthesis. Our findings show that glucocorticoids have the potential to modulate central nervous system eicosanoid production particularly under conditions of stimulated production, such as inflammatory and demyelinating disorders. This mechanism may explain, at least in part, the therapeutic benefit of glucocorticoids in patients with multiple sclerosis.     

聚焦层析分离人肝精氨酸酶同工酶组分

用聚焦层析结合DEAE-Sephadex A-50离子交换层析,从正常人肝浸液中分离得两个精氨酸酶同工酶组分.经聚丙烯酰胺凝胶电泳(PAGE)鉴定从聚焦层析得到的第一峰同工酶组分为一条蛋白带,第二峰具有精氨酸酶活性的蛋白组分的主要蛋白带也极明显。各蛋白质成分向阴极电泳的前后顺序与从聚焦层析洗脱的先后次序一致。两型同工酶的比活力分别约为2050U/mg及790U/mg。用SDS-PAGE检测两型同工酶均由两种亚基组成,且分子量近似。     

ERK信号传导通路调控乙醛刺激的肝星状细胞Na+/Ca2+泵mRNA表达的研究

目的 :探讨Erk信号传导通路调控乙醛刺激的肝星状细胞 (HSC)Na /Ca2 泵mRNA表达的影响。方法 :用链霉蛋白酶和胶原酶原位灌流 ,Metrizamide密度梯度离心分离大鼠肝星状细胞 ,采用RT PCR测定PD980 5 9阻断乙醛激活的肝星状细胞Erk活性后Na /Ca2 泵mRNA表达。结果 :乙醛刺激后 ,HSC后明显促进Na /Ca2 泵mRNA表达 (P<0 0 1) ,不同剂量PD980 5 9对肝星状细胞Na /Ca2 泵mRNA表达的影响无统计学意义。结论 :Erk信号传导通路可能对乙醛刺激的肝星状细胞激活状态的启动无明显影响     

24例病毒性、15例化脓性脑炎患者脑脊液中乳酸脱氢酶及同功酶分析

目的 :观察病毒性、化脓性脑炎脑脊液(csf)中乳酸脱氢酶 (LDH)活性及其各同功酶活性百分率的变化。方法:病毒性脑炎24例 ,化脓性脑炎15例 ,酶动力学法检测脑脊液总乳酸脱氢酶 (TLDH)活性 ,琼脂糖凝胶电泳法检测脑脊液中LDH各同功酶活性百分率。结果:病毒性脑炎与对照组比较 ,脑脊液总乳酸脱氢酶 (TLDH)明显降低 (P<0.01) ,LDH1同功酶显著降低 (P<0.01) ,LDH5显著升高 (P<0.01) ;化脓性脑炎与对照组比较脑脊液TLDH明显升高 (P<0.01) ,LDH1同功酶明显降低 (P<0.01) ,LDH5明显升高 (P<0.01)。结论:脑脊液TLDH值的测定可以鉴别病毒性、化脓性脑膜炎 ,检测脑脊液LDH各同功酶活性 (LDH1和LDH5)的变化程度对脑炎的进展及预后有一定的价值。     

三氧化二砷对人脐静脉内皮细胞中蛋白激酶C活性和白细胞介素-15分泌、表达的影响及其临床意义

目的 通过研究三氧化二砷(As2O3)对人脐静脉内皮细胞(HUVEC)中蛋白激酶C(PKC)活性和白细胞介素(IL)-15表达和分泌的影响,探讨内皮细胞在As2O3抑制白血病或肿瘤中的作用。方法用不同浓度的As2O3作用于培养的HUVEC细胞,测定其生长情况、胞膜和胞浆PKC活性以及对IL-15基因表达和分泌的影响。结果0.25 μmol／L~50 μmol／L的.As2O3均抑制HUVEC细胞的增殖(P<0.01),随着药物浓度或作用时间的增加,细胞逐渐死亡。在As2O3作用细胞4 h测定胞浆和胞膜的PKC活性,两者在不同浓度作用下活性水平均得到提升(P<0.01),但胞膜的活性上升幅度更大。在As2O3的测定浓度范围内,PKC的活性水平与As2O3的浓度呈正相关。1、5、16 μmol／L的As2O3导致IL-15基因表达和分泌水平的增加(P<0.01),并呈浓度依赖性关系。结论As2O3可能是通过激活内皮细胞的PKC活性,促进IL-15或其他细胞因子的分泌,来抑制白血病或肿瘤发展的。     

Growth factor pre-treatment differentially regulates phosphoinositide turnover downstream of lysophospholipid receptor and metabotropic glutamate receptors in cultured rat cerebrocortical astrocytes

Reactive gliosis is an aspect of neural plasticity and growth factor (GF) stimulation of astrocytes in vitro is widely regarded as a model system to study astrocyte plasticity. Astrocytes express receptors for several ligands including lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P), agonists for the G-protein-coupled lysophospholipid receptors (lpRs). Activation of lpRs by LPA or S1P leads to multiple pharmacological effects including the influx of calcium, phosphoinositide (PI) hydrolysis, phosphorylation of extracellular receptor regulated kinase (ERK), release of arachidonic acid, and induces mitogenesis. Treatment of astrocytes in vitro with a growth factor cocktail (containing epidermal growth factor [EGF], basic fibroblast growth factor [bFGF] and insulin) led to a marked attenuation of lpR-induced PI hydrolysis. In contrast, under identical conditions, GF treatment led to marked potentiation of PI hydrolysis downstream of activation of another abundantly expressed G-protein coupled receptor, mGluR5. Quantitative gene expression analysis of GF-treated or control astrocytes by TaqMan RT-PCR indicated that GF treatment did not change gene expression of lpa1 and s1p1, but increased gene expression of s1p5 which is expressed at very low levels in basal conditions. These results suggest that GF differentially affected PLC activation downstream of mGluR5 versus lpR activation and that the changes in mRNA levels of lpRs do not account for marked attenuation of agonist-induced phosphoinositide turnover.     

IL-2对垂体瘤细胞系RC-4B/C细胞分泌ACTH的影响

目的 :探讨白细胞介素 2 (IL 2 )对垂体瘤细胞系RC 4B/C细胞ACTH分泌的调控作用及其影响因素 .方法 :以放射免疫方法测定培养的垂体瘤细胞系RC 4B/C细胞的培养液中的ACTH浓度 .结果 :IL 2 (1× 10 4～ 5× 10 5U·L-1)促进RC 4B/C细胞分泌ACTH ;蛋白激酶A的抑制剂H 9(1μmol·L-1)和酪氨酸蛋白激酶的抑制剂tyrphostin2 3 (1μmol·L-1)均可显著性抑制IL 2的促ACTH分泌作用 .结论 :IL 2可促进RC 4B/C细胞分泌ACTH ,该作用与蛋白激酶A和酪氨酸蛋白激酶信号转导途径紧密相关     

Activities of creatine kinase isoenzymes in single skeletal muscle fibres of trained and untrained rats

Biochemical changes in the creatine kinase isoenzyme compositions in single muscle fibres of different types in rats were induced by endurance running training. Single muscle fibres were dissected from the soleus and extensor digitorum longus muscles of Wistarstrain male rats trained on a motor-driven treadmill for 16 weeks. Each fibre was typed histochemically (SO, slow-twitch oxidative; FOG, fast-twitch oxidative glycolytic; FG, fast-twitch glycolytic), and the activities of total creatine kinase and its four isoenzymes (CK-MM, -MB,-BB, and mitochondrial creatine kinase) were measured. The endurance training did not affect the total creatine kinase activity, but resulted in significantly increased activities of CK-MB and CK-BB in SO and FOG fibres, and the mitochondrial enzyme activity in FOG and FG fibres. Endurance training induced biochemical changes in the isoenzyme compositions, specifically in FOG fibres. These results suggest that changes in creatine kinase isoenzymes with endurance training reflect changes in the energy metabolism in the different muscle fibres, supporting the hypothesis that the different isoenzymes play different roles in energy transduction.     

红细胞同工酶ADA－EAP一AK_1同步电泳分型方法的建立

综合、改良了分别分型的方法，建立了红细胞同工酶ＡＤＡ一ＥＡＰ一ＡＫ１同步电泳分型方法，为ＡＤＡ，ＥＡＰ和ＡＫ１３种红细胞同工酶在法医学鉴定中更广泛的应用，提供了一种可靠、经济、实用的方法。