In vivo imaging of cortical membrane remodeling in rats with chronic unilateral ablation of nucleus basalis magnocellularis: use of radiolabeled palmitic acid

Membrane remodeling was imaged in vivo in brains of rats with a 2-week-old right-sided ablation of the nucleus basalis magnocellularis (NBM). To do this, [9,10-³H]palmitic acid ([³H]PAM) was injected intravenously and regional brain incorporationk^* of tracer was determined with quantitative autoradiography after 20 min circulation. In NBM-lesioned animals,k^* was elevated significantly (by up to 17%) in 11 ipsilateral frontal or parietal cortical regions, more so in layer I than in layers IV and V. Unoperated animals showed no right-left difference ink^*, whereas sham-operated animals showed some unilateral effects of damage due to the needle track. Circulating [³H]PAM is incorporated intosn-1 positions of brain phospholipids, mainly phosphatidylcholine, and its rate of turnover is thought to reflect turnover of neuronal and glial membranes. These results, when related to published evidence of altered cortical phospholipid metabolism in NBM-lesioned rats, suggest that images of increased [³H]PAM incorporation into ipsilateral cortex reflect increased membrane remodeling involving phospholipids.     

实验性甲状腺功能低下大鼠脑、红细胞膜神经磷脂与磷脂酰胆碱分子比变化的研究

应用薄层色谱扫描法，动态观察了实验性甲低大鼠脑，红细胞膜神经磷脂（ＳＭ）／磷脂酰胆碱（ＰＣ）分子比变化，结果表明持续用甲基硫脲嘧啶（ＭＴＵ）和脑发育临界期后停ＭＴＵ组，ＳＭ／ＰＣ分子比明显升高（Ｐ＜０．０５）。提示脑发育临界期内甲状腺激素缺乏，可导致生物膜的明显老化，膜磷脂分布破坏造成一系列结构和功能的改变，进而使中枢神经系统发育异常和功能障碍。     

Potentiation of A2 purinoceptor-stimulated surfactant phospholipid secretion in primary cultures of rat type II pneumocytes

Surfactant secretion is mediated by a number of different signal-transduction mechanisms. Positive and negative interactions between different signaling pathways can have an important influence on the overall regulation of secretion. To examine interactions between the adenosine A₂ receptor-mediated pathway and those involving activation of protein kinase C and a Ca⁺⁺/calmodulin-dependent system, we examined the effect of the A₂ agonist 5-(N-ethylcarboxyamido) adenosine (NECA) in combination with 2 activators of protein kinase C, 12-O-tetradecanoylphorbol-13-acetate (TPA) and dioctanoylglycerol, and the Ca ⁺⁺ ionophore ionomycin on phosphatidylcholine secretion in primary cultures of rat type 11 cells. The individual agonists increased secretion 3–5-fold over the rate in control cells. The stimulatory effects of NECA + TPA, NECA + dioctanoylglycerol, and NECA + ionomycin were 44%, 20%, and 44% greater, respectively, than expected by addition of the effects of the individual agonists. NECA increased cAMP formation while the other agonists did not. However, the effect of NECA on CAMP formation was significantly enhanced by TPA and dioctanoylglycerol, while the duration of the increase in CAMP level was prolonged by dioctanoylglycerol and ionomycin. Although tho possible involvement of other second messenger systems cannot be excluded, we speculate that the synergistic interaction between the agonists in stimulating phosphatidylcholine secretion is mediated by increased cAMP levels. Offprint requests to: S. A. Rooney     

易善复联合穴位注射治疗非酒精性脂肪肝疗效观察

目的观察易善复胶囊联合穴位注射丹参注射液治疗非酒精性脂肪肝(NAFLD)的临床效果。方法 60例NAFLD患者被随机分成治疗组38例,对照组22例。在NAFLD基础治疗的基础上,治疗组采用口服易善复胶囊联合穴位注射丹参注射液治疗,对照组仅口服易善复胶囊治疗,两组均治疗90天。观察两组治疗前后临床疗效,检测肝脏B超、谷丙转氨酶(ALT)、总胆固醇(TC)、三酰甘油(TG)、体重指数(BMI)指标。结果治疗组总有效率及显效率明显高于对照组(P0.05);治疗组ALT和BMI水平改善程度优于对照组(P0.05)。结论:易善复胶囊联合穴位注射丹参注射液治疗NAFLD可以提高临床疗效,促进患者肝功能和体重指数的恢复。     

Phosphatidylserine increases acetylcholine release from cortical slices in aged rats

Acetylcholine release was investigated in cortical slices superfused with choline-enriched Krebs solution containing physostigmine. Slices were prepared from 3 and 24 month old rats treated with either Tris buffer or sonicated suspensions of phosphatidylserine and phosphatidylcholine in Tris buffer. Slices were electrically stimulated at frequencies of 1, 2 and 5 Hz for 5 min periods preceded and followed by rest periods. ACh content of the superfusate was quantified by bioassay. In the 24 month old rats treated with Tris buffer, acetylcholine release, at all frequencies tested, was approximately 50% lower than that in the 3 month old rats. On the contrary, no significant decrease in ACh release was found in the 24 month old rats treated for 30 days with phosphatidylserine (15 mg/kg IP). The same treatment did not increase acetylcholine release in 3 month old rats. Acetylcholine release in 24 month old rats receiving a single administration of phosphatidylserine (15mg/kg IP) or phosphatidylcholine (15 mg/kg IP) for 30 days was as low as in the 24 month old rats receiving the Tris buffer only. It is proposed that the chronic phosphatidylserine treatment may reduce the age-induced decrease in acetylcholine release by acting on the stimulus-secretion coupling mechanism.     

Mechanisms whereby nerve growth factor increases diacylglycerol levels in differentiating PC12 cells

We previously showed indirectly that the increase in diacylglycerol (DAG) levels caused by exposing differentiating PC12 cells to nerve growth factor (NGF) must derive mainly from de novo synthesis and, to a lesser and transient extent, from the hydrolysis of [3H]phosphatidylinositol (PI). To explore further the biochemical mechanisms of this increase, we measured, in PC12 cells, DAG synthesis from glycerol or various fatty acids; its liberation from phosphatidylcholine (PC); and the activities of various enzymes involved in DAG production and metabolism. Among cells exposed to NGF (0-116 h), the labeling of DAG from [3H]glycerol peaked earlier than that of [3H]PC, and the specific radioactivity of [3H]glycerol-labeled DAG was much higher than those of the [3H]phospholipids, indicating that [3H]DAG synthesis precedes [3H]phospholipid synthesis. NGF treatment also increased (by 50-330%) the incorporation of monounsaturated ([3H]oleic acid) and polyunsaturated ([14C]linoleic acid or [3H]arachidonic acid) fatty acids into DAG, and, by 15-70%, into PC. NGF treatment increased the activities of long chain acyl-CoA synthetases (LCASs), including oleoyl-CoA synthetase and arachidonoyl-CoA synthetase, by 150-580% over control, but cholinephosphotransferase activity rose by only 60%, suggesting that the synthesis of DAG in the cells was increased to a greater extent than its utilization. NGF did not promote the breakdown of newly formed [3H]PC to [3H]DAG, nor did it consistently affect the activities of phospholipase C or D. NGF did increase phospholipase A2 activity, however the hydrolysis catalyzed by this enzyme does not liberate DAG. Hence the major source of the increased DAG levels in PC12 cells exposed to NGF appears to be enhanced de novo DAG synthesis, probably initiated by the activation of LCASs, rather than the breakdown of PC or PI.     

Regulatory functions of protein kinase c in glomerular mesangial cells

Summary Protein kinase C is a family of isozymes that are activated by hormone-stimulated phosphoinositide hydrolysis and participate in the signalling process by phosphorylating certain target proteins. In glomerular mesangial cells protein kinase C fulfills two major functions: it contributes to hormone-induced prostaglandin formation, and it acts as a negative feedback regulator of the inositol lipid signalling cascade. Furthermore, protein kinase C activates a phosphatidylcholine-degrading phospholipase D activity with as-yet-unknown cellular function.Abbreviations PKC protein kinase C - PLA₂ phospholipase A₂ - PLC phospholipase C - PLD phospholipase D - IP₃ inositol 1,4,5-trisphosphate - DAG 1,2-diacylglycerol     

茵胆平肝胶囊联合多烯磷脂酰胆碱治疗酒精性肝病的临床研究

目的探索茵胆平肝胶囊联合多烯磷脂酰胆碱治疗酒精性肝病的临床疗效。方法选取2014年2月—2017年4月渭南市中心医院收治的234例酒精性肝病患者,随机分为对照组和治疗组,每组各117例。对照组静脉滴注多烯磷脂酰胆碱注射液,30 m L加入5%葡萄糖注射液250 m L,1次/d。治疗组在对照组治疗基础上口服茵胆平肝胶囊,2粒/次,2次/d。两组均连续治疗30 d。观察两组患者的临床疗效,比较两组治疗前后天冬氨酸氨基转移酶(AST)、丙氨酸氨基转移酶(ALT)、总胆红素(TBil)、碱性磷酸酶(ALP)的变化情况。结果治疗后,对照组和治疗组的总有效率分别为80.34%、94.87%,两组比较差异有统计学意义(P0.05)。治疗后,两组AST、ALT、TBil、ALP水平均显著降低,同组治疗前后差异有统计学意义(P0.05);治疗后,治疗组AST、ALT、TBil、ALP水平显著低于对照组,两组比较差异有统计学意义(P0.05)。对照组和治疗组的不良反应发生率分别为28.2%、9.4%,两组比较差异有统计学意义(P0.05)。结论茵胆平肝胶囊联合多烯磷脂酰胆碱治疗酒精性肝病具有显著疗效,能明显改善患者肝功能,不良反应较少,具有一定的临床推广应用价值。     

A Calorimetric Study on Diflunisal Release from Poly(Lactide-co-Glycolide) Microspheres by Monitoring the Drug Effect on Dipalmitoylphosphatidylcholine Liposomes: Temperature and Drug Loading Influence

Diflunisal release from poly-Lactide-co-Glycolide (50:50, 34,000 MW) microspheres loaded with two different amounts of drug (2.5 +/- 0.5% and 10 +/- 0.5% w/w) was monitored by following the effects exerted by the drug on the thermotropic behavior of dipalmitoylphosphatidylcholine unilamellar vesicles at different temperatures. The effects of the drug released from the microspheres on the thermotropic behavior of lipid aqueous dispersion containing different molar ratios of drug was detected by differential scanning calorimetry and was compared with the effects exerted by the free Diflunisal. Diflunisal affects mainly the temperature (T_m) of the transition characteristic of phospholipid vesicles as model biomembrane, causing a shift toward lower values. This shift was modulated by the drug molar fraction with respect to the lipid concentration in the aqueous dispersion. Afterward, calorimetric measurements were performed on suspensions of blank liposomes added to weighed amounts of unloaded and differently Diflunisal-loaded microspheres as well as free powdered Diflunisal after incubation for increasing times at three different temperatures (25, 37, and 50°C). The T_m shifts of the lipid bilayer, caused by the drug released from polymeric system as well as by the free drug during incubation periods, were compared with that caused by free drug increasing molar fractions dispersed directly on the membrane, employed as a calibration curve to obtain the fraction of drug released. This in vitro study suggests that the kinetic process involved in drug release is influenced by the amount of drug loaded in the microspheres as well as by the temperature acting on drug solubility and membrane disorder. This drug release model, monitored by the calorimetric technique shows that a) the poly-Lactide-co-Glycolide microspheres are a good delivery system able to sustain the drug release; b) the differential scanning calorimetry technique applied on the drug interaction with biomembranes constitutes a good tool to follow the drug release; 3) this model, representing an innovative alternative in vitro model, should be used to determine the different kinetics involved in the drug transfer from a drug delivery system to a membrane as uptake site.     

复方甘草酸苷和多烯磷脂酰胆碱治疗慢性丙型肝炎

目的探讨复方甘草酸苷联合多烯磷脂酰胆碱治疗慢性丙型肝炎合并非酒精性脂肪肝的临床疗效。方法应用复方甘草酸苷联合多烯磷脂酰胆碱治疗慢性丙型肝炎30倒,并和30例常规治疗组对比。结果治疗组显效率63．33％（19／30）;总有效率为90．0％（27／30）;对照组显效率36．7％（11／30）;总有效率为66．7％（20/30）,2组总有效率相比差异有统计学意义。结论复方甘草酸苷联合多烯磷脂酰胆碱治疗慢性丙型肝炎合并非酒精性脂肪肝,治疗前后患者的症状、体征、肝功能、血脂等指标较治疗前明显改善。