甘草酸铵类制剂中甘草酸差向异构体的分析

目的:建立一种方法并依据这种方法分析甘草酸铵类制剂中18α-甘草酸和18β-甘草酸2种差向异构体的含量。方法:采用Kromasil C18(250 mm×4.6 mm,5μm)色谱柱,以0.05 mol·L-1磷酸盐缓冲液(调节pH至7.0)-乙腈(80∶20)为流动相,流速1 mL·min-1,检测波长252 nm。结果:18α-甘草酸和18β-甘草酸的线性范围分别为0.025～2.500 mg·mL-1(r=0.9990)和0.025～2.000 mg·mL-1(r=0.9990),平均加样回收率(n=9)分别为99.0%和102.5%。同一色谱图中,2个色谱峰间的分离度大于1.5。结论:所建方法可用于分析甘草酸铵类制剂中甘草酸差向异构体的含量,甘草酸铵类制剂中18α-甘草酸和18β-甘草酸比例不一,应完善标准加以控制。     

Modulation of human α(4)β(2) nicotinic acetylcholine receptors by brominated and halogen-free flame retardants as a measure for in vitro neurotoxicity

Brominated flame retardants (BFRs) are abundant persistent organic pollutants with well-studied toxicity. The toxicological and ecological concern associated with BFRs argues for replacement by safer alternatives. However, the (neuro)toxic potential of alternative halogen-free flame retardants (HFFRs) is unknown. Previous research identified the nervous system as a sensitive target organ for BFRs, with modulation of excitatory nicotinic acetylcholine (nACh) receptors as one of the modes of action. Since it is essential to assess the (neuro)toxic potential of HFFRs before large scale use, we measured the effects of three BFRs and 13 HFFRs on the function of human α(4)β(2) nACh receptors, expressed in Xenopus oocytes, using the two-electrode voltage-clamp technique. The results demonstrate that some BFRs (TBBPA and to a lesser extent BDE-209) and HFFRs (TPP, Alpi, APP, MMT and to a lesser extent ATH, ATO, MHO, MPP, RDP and ZHS) act as nACh receptor antagonists. Contrary, BPS, BDP, DOPO and ZS were unable to modulate nACh receptors. Despite the lack of toxicological data on HFFRs and the need for additional studies to perform a full (neuro)toxic risk assessment, the current data on antagonistic effects on nACh receptors could be an important step in prioritizing viable HFFRs for substitution of BFRs.     

Association between the MnSOD Ala-9Val polymorphism and development of schizophrenia and abnormal involuntary movements in the Xhosa population

Reactive oxygen species (ROS)-mediated damage has been hypothesized to play a role in the development and poor outcome of schizophrenia, as well as the development of neuroleptic-induced abnormal involuntary movements. Recently, the functional polymorphism (Ala-9Val) in the manganese superoxide dismutase (MnSOD) gene (part of the antioxidant defense mechanism) was found to be associated with schizophrenia in a Turkish population. This study was aimed at replicating this finding in a Xhosa population. In addition, the role of Ala-9Val in abnormal involuntary movement and tardive dyskinesia development in the Xhosa population was also investigated. The schizophrenic patient group (n=286) and a healthy control group (n=243) were genotyped for the Ala-9Val polymorphism using heteroduplex-single stranded conformational polymorphism (HEX-SSCP) analysis. No significant difference in genotype or allele frequency could be observed between the schizophrenia and control group (P=0.294 and P=0.528 respectively). In addition no association could be found between the polymorphism and symptom severity (SANS and SAPS). The Xhosa schizophrenia patient group with abnormal involuntary movements (n=54) and a subgroup with tardive dyskinesia (n=30) was found to significantly differ in Ala-9Val genotype frequency (P=0.008 and P=0.011 respectively) compared to the Xhosa schizophrenia patient group without abnormal involuntary movements (n=204). However, no significant difference was found for the allele frequencies (P=0.955 and P=0.161). Further, using ANCOVA no association was found between AIMS score and genotype in the group with abnormal involuntary movements (P=0.1234). However, in the patient group with tardive dyskinesia an association was observed between genotype and AIMS score (P=0.0365). These results do not support a major role of the MnSOD Ala-9Val polymorphism in the development of schizophrenia or symptom severity in the Xhosa population. Yet it seems to be involved in the development of abnormal involuntary movements and tardive dyskinesia and may even modulate the severity of tardive dyskinesia.     

cAMP mediates ammonia-induced programmed cell death in the microglial cell line BV-2

Although ammonia is a well-known neuropathogenic factor, the cellular mechanisms of ammonia toxicity are less characterized. Up to now, the main focus of ammonia toxicity has been on astrocytes and neurons. Despite the significance of microglia in neurodegenerative diseases, little is known about their responsiveness to ammonia. In the present study, we found that ammonia triggered mitosis at concentrations between 30 microm and 3.0 mm but apoptosis at concentrations >or= 1.0 mm in the murine microglial cell line BV-2. Most apoptotic cells showed an accumulation of condensed chromatin at the nuclear envelope, blebbing of the plasma membrane, formation of apoptotic bodies and an increase in caspase 3/7 activity. Blockade of caspase 3/7 activity by Ac-DEVD-CHO suppressed ammonia-induced apoptosis. Surprisingly, some BV-2 cells exposed to ammonia displayed clear signs of mitotic catastrophe, a type of cell death occurring during mitosis. In a further series of experiments, we found that cyclic adenosine 3',5'-monophosphate (cAMP) mediated the apoptogenic effects of ammonia, because (i) ammonia dose-dependently elevated the intracellular cAMP level, (ii) blockade of the adenylyl cyclase by SQ-22536 suppressed ammonia-induced apoptosis, (iii) inhibition of phosphodiesterases (PDEs) by the nonselective PDE inhibitor IBMX, or by the PDE4-selective inhibitor rolipram, increased the relative number of apoptotic cells, and (iv) the cAMP analogues 8-bromoadenosine cAMP and Sp-cAMP mimicked the effect of ammonia and triggered apoptosis. Taken together, our results indicate that distinct concentrations of ammonia trigger opposite signalling pathways in microglial cells.     

The 1.3-A resolution structure of Nitrosomonas europaea Rh50 and mechanistic implications for NH3 transport by Rhesus family proteins

The Rhesus (Rh) proteins are a family of integral membrane proteins found throughout the animal kingdom that also occur in a number of lower eukaryotes. The significance of Rh proteins derives from their presence in the human red blood cell membrane, where they constitute the second most important group of antigens used in transfusion medicine after the ABO group. Rh proteins are related to the ammonium transport (Amt) protein family and there is considerable evidence that, like Amt proteins, they function as ammonia channels. We have now solved the structure of a rare bacterial homologue (from Nitrosomonas europaea) of human Rh50 proteins at a resolution of 1.3 A. The protein is a trimer, and analysis of its subunit interface strongly argues that all Rh proteins are likely to be homotrimers and that the human erythrocyte proteins RhAG and RhCE/D are unlikely to form heterooligomers as previously proposed. When compared with structures of bacterial Amt proteins, NeRh50 shows several distinctive features of the substrate conduction pathway that support the concept that Rh proteins have much lower ammonium affinities than Amt proteins and might potentially function bidirectionally.     

复方甘草酸单铵治疗玫瑰糠疹疗效观察

目的探讨复方甘草酸单铵治疗玫瑰糠疹的疗效及其安全性。方法70例玫瑰糠疹患者分为2组,治疗组40例,给予复方甘草酸单铵注射液40ml,ivgtt,qd,;对照组30例,给予左西替力嗪5mg,qd,两组均外用炉甘石洗剂,每天2次;10d为一疗程。结果治疗组痊愈率及总有效率分别为72．5％和90．00％,对照组分别为53．33％和66．67％,两组比较均有显著性差异（P〈0．01）,两组均未见明显不良反应。结论复方甘草酸单铵治疗玫瑰糠疹疗效确切,疗程短,不良反应少,值得临床应用。     

铈盐引发丙烯腈在含醇羟基硅胶表面的接枝聚合

将偶联剂γ-(2,3-环氧丙氧基)丙基三甲氧基硅烷(EPPS)键合于硅胶微粒表面, 在酸性催化剂作用下, 键合EPPS的环氧键开环, 产生了醇羟基(HXYG), 形成表面带有醇羟基的改性微粒HXYG-SiO2。使用铈盐与硅胶表面的醇羟基构成氧化还原引发体系, 在硅胶表面实施了丙烯腈的接枝聚合,制备了接枝微粒PAN-SiO2,考察了接枝聚合的影响因素。实验结果表明：在所形成的氧化还原引发体系中,由于初级自由基即引发物种处于硅胶微粒表面, 所制备的接枝微粒PAN-SiO2具有高的接枝度(0.19 g/g), 且单体的整体接枝效率高;引发剂铈盐的浓度对接枝度有较大的影响, 铈盐浓度过大, 将会促进氧化终止过程, 降低接枝度, 适宜的铈盐浓度为5.93×10-3 mol/L;接枝度随硫酸浓度的增大呈现先增大后减小的变化规律, 当H+离子浓度为0.38 mol/L时,PAN的接枝度最高。     

硫酸铵工业尺寸结晶器的拉哥朗日多相CFD模拟

反应器内流体的流动行为和硫酸铵晶体粒子的悬浮情况,是设计工业生产硫酸铵反应器的关键。通过测定硫酸铵晶体的粒度分布（CSD）,计算出硫酸铵晶体粒子恰好悬浮时的搅拌速率为100 r/min。针对一个为实际工业生产设计的连续结晶器,进行计算流体力学（CFD）模拟,得到其稳定的单相流场,并与200 r/min搅拌速率的流场进行对比。引入拉哥朗日离散相模型,进行两相流CFD模拟,验证不同粒度的硫酸铵晶体粒子在100 r/min搅拌速率下在连续结晶器内的悬浮效果。模拟结果表明设计的硫酸铵连续结晶器是合理的。     

柠檬酸铁铵通过活性氧途径影响人丙型肝炎病毒的蛋白翻译

目的研究铁对HCV IRES依赖的病毒蛋白翻译的影响,以及其与细胞ROS活性变化的关系。方法以脂质体细胞转染法,将双荧光素酶报告基因表达载体p CI-Rluc-HCV IRES-Fluc转染人肝癌细胞系Huh-7细胞。在0、50和300μmol/L浓度的柠檬酸铁铵(FAC)作用24 h后,双荧光素酶报告基因检测系统检测HCV IRES依赖的病毒蛋白翻译的变化。ROS荧光染色方法检测细胞ROS活性变化,Western blot法检测细胞中Nrf2蛋白表达的变化。加入100μmol/L的DPI后,检测300μmol/L FAC实验组中HCV蛋白翻译的变化和细胞ROS的变化。结果与对照组相比,FAC增加了Huh-7细胞HCV IRES依赖的病毒蛋白翻译、增加了ROS活性,并且可以引起核转录因子Nrf2表达增加(P0.05)。加入ROS抑制剂DPI后,可以显著抑制FAC诱导的HCV IRES依赖的病毒蛋白翻译及Nrf2蛋白的表达(P0.05)。结论 FAC可以诱导细胞HCV IRES依赖的病毒蛋白翻译增加,可能与FAC促进Huh-7细胞产生过多的ROS有关。