Activation of membrane outward currents by human low density lipoprotein in mouse peritoneal macrophages

Summary The aim of the present study was to search for electrophysiological effects of human lipoproteins on membrane currents in mouse peritoneal macrophages which had been cultured for 5 to 20 days. Whole-cell currents were recorded by using a voltage-clamp technique.Low density lipoprotein (LDL, 100 g/ml) increased a slowly activating nonspecific cation current (i_so) in the positive potential range to 244 ± 23% of the reference (test potential + 55 mV, n = 13, P < 0.005). Augmentation of current resulted out of a negative shift of the activation curve along the voltage axis (–22 mV) and an increase of maximally available current.Furthermore, LDL increased a rapidly activating outward current (i_fo) at test potentials positive to the potassium equilibrium potential. At +55 mV i_fo-amplitude increasedto 165 ± 14% ofreference (n = 16, P < 0.005). LDL-induced effects on i_fo-current could be mimicked by application of the calcium ionophore A 23187 (1 mol/l) which led to an increase of i_fo-current to 161 ± 25% of the reference (test potential + 55 mV, n = 11, P < 0.005).Acetylated-LDL (100 g/ml, 5–15 min) produced no significant effect on the membrane currents under investigation. Correspondence to U. Borchard at the above address     

亲脂素增加血管平滑肌细胞的脂质集聚

目的 观察乙酰化的低密度脂蛋白(AcLDL)对血管平滑肌细胞亲脂素(adipophilin)表达的影响及亲脂素对血管平滑肌细胞的AcLDL摄取及脂质集聚的影响.从而探讨其在糖尿病大血管病变发生中的作用.方法 以不同浓度AcLDL干预人血管平滑肌细胞(HVSMCs).应用Northern印迹及Western印迹技术检测AcLDL对亲脂素表达的影响;以RNA干扰技术、流式细胞仪、酶法和油红O染色检测亲脂素对HVSMCs的脂质集聚及AcLDL摄取的影响.结果 AcLDL呈剂量依赖性地增加HVSMCs的亲脂素的表达,沉默亲脂素基因使HVSMCs对AcLDL的摄取(降低38.7%,P<0.05)和脂质集聚能力下降(甘油三酯、总胆固醇分别下降30.6%和29.8%,均P<0.01).结论 亲脂素促进HVSMCs摄取AcLDL,增加HVSMCs脂质集聚,这可能是亲脂素促进动脉粥样硬化的机制之一.     

Design and comparative in-vitro and in-vivo evaluation of starch-acrylate graft copolymer based salbutamol sulphate sustained release tablets

The present work deals with the development of controlled release tablets of salbutamol sulphate (SS) using graft copolymers of methyl methacrylate (St-g-PMMA and Ast-g-PMMA) on starch and acetylated starch. Formulations were evaluated for physical characteristics like hardness, friability, drug release, drug content and weight variations, which fulfilled all the official requirements of tablet dosage form. The release rates from formulated matrix tablets were studied at SGF (pH 1.2) followed by SIF (pH 6.8). Drug release from the graft copolymer based tablets was found to be sustained upto the 14 h with >75% drug release. The in-vitro release study showed that the graft copolymer based matrix formulations (F3 & F4) exhibited highest correlation value (r²) for higuchi kinetic model and Korsmeyer's model with n values between 0.61 and 0.67 proved that release mechanisms were governed by both diffusion and erosion mechanism. There was no significant difference in the pharmacokinetic parameters (t_max, C_max, AUC, K_e, and t_1/2) of the graft copolymers matrices and HPMC K100M matrix tablets, indicating their comparable sustained release effect. The potential of graft copolymers to sustain the drug release is well supported by in-vivo pharmacokinetic studies and their adequate physicochemical properties make them promising excipients for controlled drug delivery system.     

Antimicrobial and demelanizing activity of Ganoderma lucidum extract,p-hydroxybenzoic and cinnamic acids and their synthetic acetylated glucuronide methyl esters

Mushroom extracts or isolated compounds may be useful in the search of new potent antimicrobial agents. Herein, it is described the synthesis of protected (acetylated) glucuronide derivatives of p-hydroxybenzoic and cinnamic acids, two compounds identified in the medicinal mushroom Ganoderma lucidum. Their antimicrobial and demelanizing activities were evaluated and compared to the parent acids and G. lucidum extract. p-Hydroxybenzoic and cinnamic acids, as also their protected glucuronide derivatives revealed high antimicrobial (antibacterial and antifungal) activity, even better than the one showed by commercial standards. Despite the variation in the order of parent acids and the protected glucuronide derivatives, their antimicrobial activity was always higher than the one revealed by the extract. Nevertheless, the extract was the only one with demelanizing activity against Aspergillus niger. The acetylated glucuronide derivatives could be deprotected to obtain glucuronide metabolites, which circulate in the human organism as products of the metabolism of the parent compounds.     

A comparison of the effects of lactose and of two chemically modified waxy maize starches on mineral metabolism in the rat

Diets containing 30% by weight of waxy maize starch, lactose monohydrate, acetylated distarch phosphate (EEC No. 1414) or acetylated distarch adipate (EEC No. 1422) were fed to weanling female Specified Pathogen-Free Sprague-Dawley rats for 1 yr and to similar 9-month-old rats for 34 wk. Behaviour and general health were unaffected by the different diets and there were no diet-related differences in food consumption. At the end of the experiment with 9-month-old rats the mean body weight of the animals receiving lactose was significantly lower than that of the controls receiving starch. The animals receiving the modified starches were slightly but not significantly heavier than the controls at the end of both experiments. The main treatment-related changes in rats on the three test diets were (1) caecal enlargement, (2) increased urinary excretion of calcium, (3) increased renal calcification as measured by chemical analysis of renal tissue obtained at autopsy and (4) increased medullary and pelvic nephrocalcinosis as assessed histopathologically. Acetylated distarch adipate had a slightly greater effect on the above parameters than acetylated distarch phosphate but both modified starches had less effect than lactose. The calcium content of the kidneys, as measured by chemical analysis or histopathology, increased with age, even in the animals receiving the control diet. This change may be due to excessively high concentrations of calcium and phosphorus in all the diets, including the control diet. Cortico-medullary mineral deposits were not a feature in these studies possibly because the diets were not deficient in magnesium. The importance of correct dietary formulation in long-term toxicity studies is emphasized.     

ALS小鼠脊髓组织GFAP蛋白赖氨酸的乙酰化修饰

目的 探讨肌萎缩脊髓硬化症(ALS)模型小鼠脊髓组织胶质纤维酸性蛋白(GFAP)中赖氨酸的乙酰化修饰。方法 对4个月左右的ALS模型小鼠进行麻醉处死,提取小鼠脊髓组织总蛋白,通过GFAP抗体和乙酰化抗体,运用免疫沉淀和免疫蛋白印迹技术鉴定GFAP蛋白的表达与GFAP蛋白赖氨酸的乙酰化修饰,通过液相二级质谱连用(LC-MS/MS)检测ALS模型小鼠脊髓组织中GFAP赖氨酸的乙酰化修饰位点。结果 免疫沉淀和免疫蛋白印迹方法发现ALS模型小鼠脊髓组织中GFAP蛋白存在赖氨酸乙酰化修饰;LC-MS/MS发现GFAP的394位和402位赖氨酸位点发生乙酰化修饰。结论 ALS小鼠模型脊髓组织中,GFAP的赖氨酸位点能被乙酰化修饰,该修饰可能参与了ALS的发生。     

亲脂素增加血管平滑肌细胞的脂质集聚

目的 观察乙酰化的低密度脂蛋白(AcLDL)对血管平滑肌细胞亲脂素(adipophilin)表达的影响及亲脂素对血管平滑肌细胞的AcLDL摄取及脂质集聚的影响.从而探讨其在糖尿病大血管病变发生中的作用.方法 以不同浓度AcLDL干预人血管平滑肌细胞(HVSMCs).应用Northern印迹及Western印迹技术检测AcLDL对亲脂素表达的影响;以RNA干扰技术、流式细胞仪、酶法和油红O染色检测亲脂素对HVSMCs的脂质集聚及AcLDL摄取的影响.结果 AcLDL呈剂量依赖性地增加HVSMCs的亲脂素的表达,沉默亲脂素基因使HVSMCs对AcLDL的摄取(降低38.7%,P<0.05)和脂质集聚能力下降(甘油三酯、总胆固醇分别下降30.6%和29.8%,均P<0.01).结论 亲脂素促进HVSMCs摄取AcLDL,增加HVSMCs脂质集聚,这可能是亲脂素促进动脉粥样硬化的机制之一.     

HMGB1乙酰化在脓毒症相关性脑病中的作用

目的探讨高迁移率族蛋白1(HMGB1)乙酰化在脓毒症相关性脑病(SAE)大鼠认知功能中的作用及HMGB1抑制剂对其的影响。方法成年雄性SD大鼠48只,随机分为三组,每组16只:假手术组(S组)、盲肠结扎穿孔术组(C组)、盲肠结扎术+正丁酸钠组(B组)。采用盲肠结扎穿孔法(CLP)建立SAE模型,S组只做假手术。S组和C组大鼠于CLP术后30min和4h分别腹腔注射生理盐水5ml/kg,B组大鼠于CLP术后30 min和4h分别侧脑室注射正丁酸钠500 mg/kg。CLP术后第4天行Morris水迷宫测试,CLP术后第7天行空间探索实验,并记录探索时间。行为学测试结束后取大鼠海马组织,Western blot法测定IL-6浓度、脑源性神经营养因子(BDNF)、HMGB1和乙酰化HMGB1的含量。结果C组逃避潜伏期明显长于S组,探索时间明显短于S组(P0.05);B组逃避潜伏期明显短于C组,探索时间明显长于C组(P0.05)。C组海马IL-6浓度、HMGB1和乙酰化HMGB1含量明显高于S组(P0.05),BDNF含量明显低于S组(P0.05);B组海马IL-6浓度、HMGB1和乙酰化HMGB1含量明显低于,BDNF含量明显高于C组(P0.05)。结论 HMGB1抑制剂正丁酸钠可抑制SAE大鼠海马内HMGB1乙酰化的表达,减轻脓毒症诱发的认知功能损伤。     

亲脂素增加血管平滑肌细胞的脂质集聚

目的 观察乙酰化的低密度脂蛋白(AcLDL)对血管平滑肌细胞亲脂素(adipophilin)表达的影响及亲脂素对血管平滑肌细胞的AcLDL摄取及脂质集聚的影响.从而探讨其在糖尿病大血管病变发生中的作用.方法 以不同浓度AcLDL干预人血管平滑肌细胞(HVSMCs).应用Northern印迹及Western印迹技术检测AcLDL对亲脂素表达的影响;以RNA干扰技术、流式细胞仪、酶法和油红O染色检测亲脂素对HVSMCs的脂质集聚及AcLDL摄取的影响.结果 AcLDL呈剂量依赖性地增加HVSMCs的亲脂素的表达,沉默亲脂素基因使HVSMCs对AcLDL的摄取(降低38.7%,P<0.05)和脂质集聚能力下降(甘油三酯、总胆固醇分别下降30.6%和29.8%,均P<0.01).结论 亲脂素促进HVSMCs摄取AcLDL,增加HVSMCs脂质集聚,这可能是亲脂素促进动脉粥样硬化的机制之一.