尼莫地平对氧化型低密度脂蛋白培养的内皮细胞不对称二甲精氨酸的影响

目的：探讨氧化型—低密度脂蛋白(ox—LDL)对体外培养的人脐静脉内皮细胞(HUVECs)培养液中内源性一氧化氮合酶抑制剂一不对称二甲精氨酸(ADMA)的影响及尼莫地平的干预作用。方法：采用改良的Jaffe法原代培养人脐静脉内皮细胞(HUVECs)，取3-6代HUVECs用于实验。用Cu^ 引发脂质过氧化过程，制备氧化型低密度脂蛋白。按实验要求加入不同浓度的ox—LDL和尼莫地平，与内皮细胞共同孵育(37℃，5％CO^2)24h后，收集细胞及培养液。高效液相色谱法(HPLC)测定ADMA、L—arg的浓度。流式细胞仪测定细胞内Ca^ 含量，同时测定培养液NO、ET含量。结果：与空白对照组比较，ox—LDL使HUVECs产生ADMA的量呈浓度依赖性增加，ET及细胞内Ca^ 量显著升高；而合成NO的量减少。尼莫地乎能显著减少ox—LDL诱导的ADMA增加，增加N0的合成，同时细胞内Ca^ 含量及CT降低，而合成N0的底物L-arg无明显变化。结论：ox—LDL增加内源性NOS抑制剂—ADMA的产生，导致内皮细胞的功能障碍。尼莫地平能减少ox—LDL诱导的ADMA增加，从而减轻ox—LDL诱导的内皮细胞代谢功能障碍。     

注射用还原型谷胱甘肽质量标准分析方法--HPLC法的建立与验证

目的建立注射用还原型谷胱甘肽含量及有关物质氧化型谷胱甘肽(GSSG)的质量标准分析方法--HPLC法,并对其进行验证.方法采用Waters Nova-Pak(R) C1g色谱柱(3.9 mm×150 mm,4 μm),0.05 mol·L-1磷酸二氢钾的溶液(含0.01 mol·L-1庚烷磺酸钠,用磷酸调节pH至3.0)-甲醇(973,V/V)为流动相,检测波长210 nm,柱温30℃.结果GSH在0.01～1 g·L-1浓度范围内呈良好的线性关系,r=0.999 9,n=6;平均回收率为99.72%,RSD=0.43%,n=9;日内精密度RSD为0.41%(n=6),日间精密度RSD为0.49%(n=5).GSSG在0.5～50 mg·L-1浓度范围内呈良好的线性关系,r=1.000 0,n=7;最低检测限为1 ng(rSN=3),定量限为5ng(rSN=10);平均加样回收率为99.0%,RSD=0.61%,n=9.结论本法简便、专属性好、准确可靠,可作为注射用还原型谷胱甘肽的质量标准分析方法.     

Oxidized high-density lipoprotein induces neuron death

High-density lipoprotein (HDL) exists within the brain and is highly vulnerable to oxidative modifications. The focus of the present study was to determine the effect of HDL and oxidized HDL (oxHDL) upon neurons, astrocytes, and microglia. Administration of highly oxidized HDL, but not native, minimally, or moderately modified HDL resulted in a dose- and time-dependent increase in oxidative stress and death of cultured rat embryonic neurons. Astrocyte and microglia cultures treated with highly oxidized HDL displayed increased reactive oxygen species formation but no toxicity. Application of oxHDL exacerbated oxidative stress and neuron death induced by beta-amyloid peptide. Studies using pharmacological inhibitors implicate the involvement of calcium and reactive oxygen species in oxHDL-induced neuronal loss. Neural cells expressing increased levels of BCL-2 had decreased levels of oxidative stress and neuron death following exposure to oxHDL. Together, these data demonstrate that oxHDL increases oxidative stress in neurons, astrocytes, and microglia which ultimately culminate in neuron death.     

染料木黄酮对ox-LDL诱导人静脉平滑肌细胞MCP-1表达的影响

目的: 研究染料木黄酮(Gen)对氧化型低密度脂蛋白(ox-LDL)诱导的人脐静脉血管平滑肌细胞(hUVSMC)单核细胞趋化蛋白-1(MCP-1)mRNA和蛋白表达的影响。方法: 以hUVSMC为对象,采用逆转录聚合酶链反应和酶联免疫吸附试验观察不同浓度Gen(1.0×10-5、3.0×10-5、9.0×10-5 mol/L)对ox-LDL诱导的MCP-1 mRNA和蛋白表达的影响。结果:三种浓度的Gen均能明显降低ox-LDL诱导的hUVSMC MCP-1mRNA 和蛋白的表达,且高剂量与生理浓度的17b-雌二醇有相近的作用。结论:染料木黄酮能下调ox-LDL诱导的hUVSMC MCP-1mRNA和蛋白的表达,这可能是染料木黄酮抗动脉粥样硬化的重要机制之一。     

Calcium content mediated hemostasis of calcium-modified oxidized microporous starch

Abstract

Blood coagulates are closely related to calcium ions (coagulation factor IV), and calcium-doped biomaterials have been reported to be effective in hemostasis. However, the effects exerted by calcium on hemostatic agents have not been previously investigated. The aims of this work were to develop calcium-modified oxidized microporous starch (CaOMS) with controllable calcium contents and to explore the relationship between calcium content and hemostatic effects. The results showed that low calcium content promoted coagulation, while high calcium content inhibited coagulation. CaOMS3 with 2.2 mg/g calcium content was optimal because of its excellent water absorption performance that enhanced physical coagulation, the rapid initiation of coagulation cascade reactions, and the enhanced chemical coagulation by RBC aggregation and platelet activation. The synergistic effects of chemical activation and physical absorption endowed CaOMS with the potential to control internal organ bleeding. These results suggested that CaOMS may be a promising hemostatic agent with wide spread applications.     

Different Roles of N-Terminal and C-Terminal Domains in Calmodulin for Activation of Bacillus anthracis Edema Factor

Bacillus anthracis adenylyl cyclase toxin edema factor (EF) is one component of the anthrax toxin and is essential for establishing anthrax disease. EF activation by the eukaryotic Ca²⁺-sensor calmodulin (CaM) leads to massive cAMP production resulting in edema. cAMP also inhibits the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase, thus reducing production of reactive oxygen species (ROS) used for host defense in activated neutrophils and thereby facilitating bacterial growth. Methionine (Met) residues in CaM, important for interactions between CaM and its binding partners, can be oxidized by ROS. We investigated the impact of site-specific oxidation of Met in CaM on EF activation using thirteen CaM-mutants (CaM-mut) with Met to leucine (Leu) substitutions. EF activation shows high resistance to oxidative modifications in CaM. An intact structure in the C-terminal region of oxidized CaM is sufficient for major EF activation despite altered secondary structure in the N-terminal region associated with Met oxidation. The secondary structures of CaM-mut were determined and described in previous studies from our group. Thus, excess cAMP production and the associated impairment of host defence may be afforded even under oxidative conditions in activated neutrophils.     

Plasma oxidized high-density lipoprotein and glycated apolipoprotein A-I concentrations in ST-segment elevation myocardial infarction patients with stress hyperglycaemia or high thrombus burden

Abstract

Background: High-density lipoprotein (HDL) particles exert many beneficial actions that may help protect against cardiovascular disease. However, recent work has demonstrated that HDL can be oxidized and glycated under certain circumstances and may become pro-atherogenic. The present study investigated the impact of oxidized high-density lipoprotein (ox-HDL) and glycated apolipoprotein A-I (gly-ApoA-I) in patients presenting with ST-elevation myocardial infarction (STEMI).

Methods: We assessed 55 consecutive patients with STEMI. Patients were divided into: (1) a stress hyperglycaemia (SH) and a no SH group; and (2) a high thrombus burden (HTB) group and a low thrombus burden (LTB) group. Meanwhile, 48 healthy volunteers were recruited as controls. Plasma ox-HDL and gly-ApoA-I concentrations were measured on admission and 7?days after admission.

Results: Higher concentrations of ox-HDL and gly-ApoA-I were found in the STEMI group than in the control group on admission and at d7. Further subgroup analysis showed that ox-HDL and gly-ApoA-I were higher in the SH group than in the no SH group at both time points; the HTB group had higher ox-HDL and ox-HDL/HDL-C levels than the LTB group on admission and at d7. However, gly-ApoA-I and the relative intensity of ApoA-I glycation showed no significant differences between the HTB and LTB groups.

Conclusions: The present data indicate that: (1) SH is associated with increased plasma concentrations of ox-HDL and gly-ApoA-I and therefore aggressive treatment is recommended; and (2) that ox-HDL and ox-HDL/HDL-C were higher in the HTB group and may be used to quantify thrombus burden.