铂复合盐与甲苯二异氰酸酯致敏大鼠体内抗原特异性IgG水平的观察

30只大鼠分成5组,分别用铂牛血清白蛋白结合物(Pt-BSA)及甲苯二异氰酸酯牛血清白蛋白结合物(TDI-BSA)加弗氏完全佐剂(CFA),以及单用BSA-CFA,NS,CFA作为对照给大鼠腹腔内注射进行免疫。分别于免疫前、免疫后2周、4周采血。用酶联免疫吸附实验(ELISA)以铂人血清白蛋白结合物(Pt-HSA)、甲苯二异氰酸酯人血清白蛋白结合物(TDI-HSA)为抗原,单克隆鼠抗大鼠IgG-HRPO抗体进行抗原特异性IgG(S-IgG)测定。结果发现用Pt-BSA、TDI-BSA致敏动物后,体内存在S-IgG,其水平随免疫时间的延长或加强免疫而递增。对照组不存在这种S-IgG的增加。用S-IgG抑制试验证明这种抗体具有明显的半抗原特异性。     

Effect of adsorbed uracil and its derivatives on the rate of oxygen reduction on platinum in acid electrolytes

The rate of oxygen reduction in 0.5 M H₂SO₄ has been controlled by adsorbing uracil and its alkyl derivatives on a Pt electrode. Addition of an ethyl group to C(5), or methyl groups to the C(5) and C(6) positions of uracil, enhances the reaction rate. 5-Ethyluracil and 5,6-dimethyluracil have such an effect, however, only when their concentrations in the electrolyte are ≤0.1 mM. Substitution of the hydrogen on N(3) with CH₃, or exocyclic oxygens with OCH₃ groups results in the inhibition of the reaction; 1,3-dimethyluracil and 2,4-dimethoxypyrimidine (0.1 mM) are two systems that cause inhibition. Interaction between the surface Pt atoms and the N(3) and O sites on the organic molecule, especially in the presence of CH₃ or C₂H₅ groups on the C(5) and/or C(6) centers, are essential for the enhancement. Results of rotating disk electrode experiments suggest that at low overpotentials, 5-ethyluracil and 5,6-dimethyluracil increase the exchange current to produce higher reaction rates.     

Flexible amperometric transducers for biosensors based on a screen printed three electrode system

Screen printed three electrode sensors comprising a platinum working, a carbon counter and an Ag ∣ AgCl pseudo reference electrode were developed employing polymer thick film inks. The sensors were constructed as amperometric transducers for multianalyte biosensors for use in batch, as well as in flow through systems. The characteristics of the sensors were determined. The active surface area of the Pt working electrodes was determined using electrochemical and SEM studies. Cyclic voltammograms of the ferricyanide/ferrocyanide couple showed that the reaction was quasi-reversible at these electrodes. Although the surface was not ideal for this redox couple, the sensors proved to be reproducible and well suited for the determination of hydrogen peroxide and thus for biosensors based on oxidases as biologically active compounds. The combination of two pretreatment steps, an additional heat curing and an electrochemical preconditioning step, was found to be most helpful to reduce background current and settling time of the sensors. Different aspects of the changing surface composition are discussed. The sensors with optimized preconditioning showed linear ranges from 10 μM up to at least 500 μM hydrogen peroxide and sensitivities of 6.97±0.20 nA μM^?1 hydrogen peroxide for uncovered, 4.01±0.08 nA μM^?1 hydrogen peroxide for PCS/BSA membrane covered and 0.222±0.002 nA μM^?1 hydrogen peroxide for Nafion^® coated platinum working electrodes. Moreover, optimized transducers with immobilized sarcosine oxidase (sensitivity: 2.30±0.07 nA μM^?1 sarcosine) demonstrated the feasibility of the sensor concept, the manufacturing and pretreatment processes for the development of enzyme sensors.     

Oxidation of methylamine and ethylamine on Pt single crystal electrodes in acid medium

Cyclic voltammetry (CV) and Fourier transform infrared reflection-absorption spectroscopy (FT-IRRAS) have been combined to analyse the oxidation of methylamine and ethylamine on platinum single crystal electrodes in an acidic medium. The oxidation of both amines on Pt(hkl) electrodes gives rise to the formation of adsorbed cyanide ad-layers, which have been detected by in situ infrared spectroscopy. In the case of Pt(111) the resulting adsorbed cyanide is rather stable but, on the contrary, the adsorbed CN-like species is highly reactive on Pt(100). It yields either adsorbed NO and CO₂ when the electrode is polarised above 0.7 V or adsorbed CO below 0.4 V. The detection of adsorbed cyanide is difficult to achieve at the Pt(110) surface. In the case of ethylamine, these adsorbed species are present in lower coverage than for methylamine. The substitution of one hydrogen atom by a methyl group in the methylamine makes the amine molecule more stable. So, the behaviour of ethylamine provides evidence for its lower electrochemical reactivity when compared with that of the methylamine molecule.     

Electrochemical surface reactions of intermediates formed in the oxidative ethanol adsorption on porous Pt and PtRu

The oxidative ethanol adsorption and electrochemical surface reactions of adsorbed intermediates were studied on electrodeposited Pt, Ru, Pt_0.92Ru_0.08 and Pt_0.85Ru_0.15 in 1 M HClO₄. A flow cell procedure was performed in order to separate surface reactions of intermediates formed in the oxidative ethanol adsorption from those reactions for ethanol in the bulk electrolyte solution. Oxidation and reduction reactions of adsorbed species were studied by potential-controlled electrodesorption spectrometry. No adsorbate formation was observed on a pure Ru electrode. In all cases, CO₂ was the sole product formed in the oxidative electrodesorption of the adsorbates. Using ¹²CH₃¹²CH₂OH and ¹²CH₃¹³CH₂OH, the oxidation reaction pathways of each C-atom to CO₂ were followed. On the other hand, methane and ethane were detected during the reductive electrodesorption of adlayer species. The onset potential for these reduction products shifts to more negative potentials as the Ru content of the alloy increases. The methane to ethane yield ratio decreases in the sequence Pt>Pt_0.92Ru_0.08>Pt_0.85Ru_0.15. A critical interpretation of the experimental data leads to a tentative yield of different adsorbed species as function of the Ru surface concentration.     

维生素C对顺铂诱导卵巢癌CAOV3细胞凋亡的影响

目的探讨维生素C是否能影响顺铂诱导卵巢癌CAOV3细胞凋亡,以及它对细胞内端粒酶活性的影响。方法MTT法和流式细胞术检测细胞生长和凋亡的情况,TRAP-ELISA法测定端粒酶活性变化。结果DDP联合AA作用组比单独用DDP组细胞凋亡率明显增高,端粒酶活性明显降低。单独10μmol/LDDP处理组细胞生长未受到明显抑制,但联合AA后其生长受到抑制。结论AA能增强DDP诱导卵巢癌CAOV3细胞凋亡,并增强DDP对细胞内端粒酶活性的抑制作用。     

氨磷汀预防铂类神经毒性疗效与安全性的Meta分析

目的:系统评价氨磷汀预防铂类神经毒性的临床疗效和安全性。方法:计算机检索Co-chrane图书馆、Pubmed、Embase、Cancerlit、中国生物医学文献数据库(CBM)、中国期刊全文数据库(CNKI)和中文科技期刊全文数据库维普(VIP)、临床对照试验库,按照纳入与排出标准选择相关的随机对照试验,检索时间为1978年1月至2012年4月。在提取资料和评价质量后,用RevMan5.1.4软件进行Meta分析。结果:共纳入11个研究,合计949例患者,其中英文6篇,中文5篇。Meta分析结果显示:氨磷汀组能有效地减少神经毒性的发生[RR=0.57,95%CI(0.39,0.82),P=0.002],严重神经毒性的发生[RR=0.49,95%CI(0.29,0.84),P=0.009],加重呕吐的发生率[RR=1.36,95%CI(1.02,1.81),P=0.04],易发生低血压[RR=2.33,95%CI(1.29,4.23),P=0.005]。在恶心发生率[RR=1.20,95%CI(0.97,1.50),P=0.10]、头晕的发生率[RR=1.44,95%CI(0.50,4.12),P=0.50]上无统计学差异。结论:氨磷汀与铂类药物化疗时联合应用能有效地预防铂类神经毒性的发生,但会加重呕吐的发生,并容易产生低血压等不良反应。     

铂类抗肿瘤药联合甘露聚糖肽治疗恶性胸腔积液的系统评价

目的:系统评价甘露聚糖肽注射液治疗恶性胸腔积液的有效性及安全性。方法:电子检索Cochrane图书馆、Medline、Embase、CNKI、VIP、CBM,手工检索相关杂志、会议论文、学位论文,收集甘露聚糖肽治疗恶性胸腔积液的随机及半随机对照试验。由2名研究者独立选择试验、评价质量、提取数据,并交叉核对。使用RevMan5.0软件进行Meta分析。结果:纳入17个研究,分为3个亚组,结果显示:(1)近期疗效:亚组A、B中治疗组优于对照组[RR=1.38,95%C(I1.27,1.50),P<0.01],[RR=1.34,95%CI(1.17,1.54),P<0.01],亚组C中2组差异无统计学意义;(2)KPS评分:治疗组优于对照组[RR=1.82,95%CI(1.51,2.20),P<0.01];(3)生存期:治疗组优于对照组(P<0.05);(4)不良反应:使用甘露聚糖肽可能减少由铂类抗肿瘤药引起的骨髓抑制、胃肠道反应及胸痛反应,但其可引起轻微发热。结论:联用甘露聚糖肽可提高铂类抗肿瘤药化疗的近期疗效,减轻不良反应,改善生活质量,但其可引起轻微发热。但由于纳入研究的方法质量较低和可能存在发表偏倚,上述结论有待进一步开展大样本、高质量、多中心的随机双盲对照试验来证实。     

Calculations of the exchange current density for hydrogen electrode reactions: A short review and a new equation

After reviewing relevant equations for the calculation of exchange current density, a new equation is derived for hydrogen electrode reactions to correct for the influences of the hydrogen concentration change in the vicinity to the electrode surface. This equation is able to describe the polarization curve shape in the small polarization region as well as to calculate the exchange current (density). The abilities of this equation are demonstrated by the data obtained with a Pt rotating disk electrode in 0.1 mol l⁻¹ KOH solution. The exchange current density at 298 K under 1 atmosphere hydrogen pressure is found to be 0.103 mA cm⁻² with an apparent activation energy of 33.5 kJ mol⁻¹. At a constant temperature, the exchange current is found to be proportional to the square root of the hydrogen partial pressure in the solution.     

Differences in the cellular response and signaling pathways of cisplatin and BBR3464 ([[trans-PtCl(NH3)(2)]2mu-(trans-Pt(NH3)(2)(H2N(CH2)(6)-NH2)2)]4+) influenced by copper homeostasis

[[trans-PtCl(NH(3))(2)](2)mu-(trans-Pt(NH(3))(2)(H(2)N(CH(2))(6)-NH(2))(2))](4+) (BBR3464) is a cationic trinuclear platinum drug that is being evaluated in phase II clinical trials for treatment of lung and ovarian cancers. The structure and DNA binding profile of BBR3464 is different from drugs commonly used clinically. It is of great interest to evaluate the difference between the mechanisms of uptake employed by BBR3464 and cisplatin (c-DDP), as altered uptake may explain chemoresistance. Using transfected cell lines, we show that both c-DDP and BBR3464 use the copper transporter hCTR1 to enter cells and to a lesser extent, the ATP7B transporter to exit cells. Copper influenced c-DDP and BBR3464 uptake similarly; it increased the c-DDP and BBR3464 uptake in ovarian (A2780) and colorectal (HCT116) carcinoma cell lines as detected by ICP-OES. However, the effects of copper on c-DDP- and BBR3464-mediated cytotoxicity differed. Copper decreased c-DDP-induced apoptosis, caspase-3/7 activation, p53 induction and PARP cleavage in cancer cell lines. In contrast, copper increased BBR3464-induced apoptosis, and had little effect on caspase activation, PARP cleavage, and p53 induction. It was concluded that BBR3464 employs mechanisms of intracellular action distinct from c-DDP. Although these drugs use the same cellular transporters (hCTR1 and ATP7B) for influx and efflux, downstream effects are different for the two drugs. These experiments illustrate fundamental differences in the mechanisms of action between cisplatin and the novel Pt-based drug BBR3464.