Voltammetric investigation of diethylstilbestrol

In this work electrooxidation of diethylstilbestrol (DES) was investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) using a glassy carbon (GC) electrode. It was statistically shown that both methods could be used for the determination of DES in the concentration range of 2×10⁻⁵–6×10⁻⁴ M by CV and 1×10⁻⁵–1×10⁻³ M in methanol (MeOH) and 4×10⁻⁵–6×10⁻⁴ M in acetonitrile (ACN) by DPV and both of the methods could be applied to human serum. A mechanism was proposed about the electrooxidation of this substance.     

Relative Reactivity of Dihydropyridine Derivatives to Electrogenerated Superoxide Ion in DMSO Solutions: A Voltammetric Approach

Purpose. To evaluate the reaction of a large series of pharmacologically significant 1,4-dihydropyridine (1,4-DHP) compounds with superoxide (O^·– ₂) in dimethylsulfoxide using differential pulse voltammetry and controlled potential electrolysis. Methods. Differential pulse voltammetry was used to track the consumption of O^·– ₂, and controlled potential electrolysis was used to electrogenerate O^·– ₂. Results. With the addition of 1,4-DHP, the oxidation peak current of O^·– ₂ decreased concentration dependently, suggesting that 1,4-DHP reacts with O^·– ₂, that is, 1,4-DHP scavenges O^·– ₂ in dimethylsulfoxide. Conclusions. A very easy and direct voltammetric procedure to study the relative reactivity of different 1,4-DHP with O^·– ₂ is proposed. Using the proposed method we have found that all commercial 1,4-DHP reacts with O^·– ₂. The following order of rates was obtained: felodipine vitamin E > isradipine > nimodipine > furnidipine > nitrendipine > nisoldipine > nifedipine. Furthermore, it was demonstrated that the hydrogen at the N-position of 1,4-DHP compounds could be released as a proton in the presence of O^·– ₂, thus the electrogenerated O^·– ₂ worked as a proton acceptor to 1,4-DHP.     

地高辛的半微分阴极吸附伏安法研究

作者用半微分阴极吸附伏安法测定地高辛的方法，在1．0×10－3mol／LNaOH底液中，于—1．0V富集2min，以100mV／s向阴极扫描，有一稳定的还原峰。在地高辛浓度为4．0×10－7mol／L～10．0×10－7mol／L范围内，该还原峰峰高与地高辛浓度成线性，检出下限为1．0×10－8mol／L。本文用不同的电化学方法证明，地高辛在悬汞电极上的电极过程为吸附准可逆过程，其饱和吸附量为6．51×10－10mol／cm2，转移系数为0．78。     

胶圈套扎术联合外痔切剥术治疗混合痔100例

目的观察胶圈套扎术联合外痔切剥术治疗混合痔的临床疗效。方法将200例混合痔患者随机分为治疗组和对照组（各100例）,治疗组采用胶圈套扎术联合外痔切剥术治疗,对照组采用传统的外剥内扎术治疗;观察两组临床疗效及术后疼痛、水肿等并发症情况。结果治疗组、对照组总有效率均为100％;组问临床疗效比较,差异无统计学意义（P〉0．05）。治疗组、对照组术后第3天、第7天与第1天及第7天与第3天组内比较,疼痛和水肿积分差异均有统计学意义（P〈0．05）;组问同期比较,各观察时间点疼痛和水肿积分差异均有统计学意义（P〈0．05）。治疗组、对照组住院时间和创面愈合时间比较,差异有统计学意义（P〈0．05）。结论胶圈套扎术联合外痔切剥术治疗混合痔疗效确切。     

大量抗坏血酸存在下多巴酚丁胺的铂电极测定

利用多巴酚丁胺 (1)的盐酸 (或硫酸 )溶液在铂电极上能催化苯胺氧化的性质对其进行了准确定量测定。在含0 .2 0 mol/ L苯胺的 0 .10 mol/ L HCl(或 0 .0 5 mol/ L H2 SO4)溶液中 ,做循环伏安扫描 ,溶液中的苯胺能还原 1的氧化产物 ,而自身变成氧化态 ,利用它可在 0 .34 5 V(SCE)左右产生一对可逆的氧化还原峰以定量测定 1,线性范围为1.1× 10 - 6～ 3.5× 10 - 4 mol/ L ,检测限为 2 .0× 10 - 7mol/ L。在本试验条件下由于测量峰电位存在显著负移 ,即使存在 10 0倍的抗坏血酸亦不会发生干扰。     

抗癌药物马蔺子素的β-环糊精包络物研究

目的研究抗癌药物马蔺子素与β-环糊精的主-客体包络行为。方法在悬汞电极上用循环伏安法考察β-环糊精不存在和存在时马蔺子素还原波的变化。结果在0.04 mol·L^-1 KH₂PO₄-Na₂HPO₄ (pH 6.8)近生理介质中,β-环糊精的引入使马蔺子素的还原波峰电流降低,峰电位正移。结论电活性客体分子马蔺子素与主体分子β-环糊精生成1∶1的包络物。用“电流法”测得其形成常数K_f值为1.92×10³ L·mol^-1。包络物的生成增强了马蔺子素的稳定性。     

In vivo voltammetric studies on release mechanisms for cocaine with γ-butyrolactone

The effect of cocaine (20 mg/kg SC) on presynaptic mechanisms of release for dopamine (DA) and for serotonin (5-HT) was studied in nucleus accumbens of unrestrained rats (Rattus norvegicus). The studies were done by assaying synaptic concentrations of DA and 5-HT in the presence of the neuronal impulse flow inhibitor, γ-butyrolactone (γ-BL). The results were compared with cocaine effects on accumbens DA and 5-HT in the freely moving rat, without γ-BL treatment. A neurochemical time course profile showed that the cocaine-induced increase in accumbens synaptic concentrations of DA was significantly blocked (p<0.0001) after DA impulse flow was significantly inhibited (p<0.0038) by γ-BL (35.8%). The neurochemical time course profile concurrently showed that the cocaine-induced decrease in accumbens synaptic concentrations of 5-HT was significantly blocked (p<0.0004) after impulse flow was significantly inhibited (p<0.025) by γ-BL (50.6%). The findings show that cocaine's effects on synaptic concentrations for DA and for HT in accumbens are dependent on neuronal impulse flow. The findings indicate that presynaptic releasing mechanisms, which may be different for DA vis-à-vis 5-HT, play a role in the mechanism of action of cocaine.     

Influence of anaesthetics on rat striatal dopamine metabolism in vivo

The effects of 4 anaesthetics, halothane, α-chloralose, chloral hydrate and pentobarbitone, on rat striatal extracellular dihydroxyphenylacetic acid (DOPAC) levels were determined using in vivo voltammetry. Stable baseline levels of DOPAC were maintained under halothane/N ₂O and α-chloralose while the extracellular levels of DOPAC gradually declined under chloral hydrate or pentobarbitone anaesthesia. Administration of haloperidol (0.3 mg/kg i.p.) significantly increased DOPAC using halothane/N ₂O, α-chloralose or chloral hydrate but not under pentobarbitone anaesthesia. The greatest increase in DOPAC was seen in rats anaesthetized with α-chloralose>halothane/N₂O>chloral hydrate > pentobarbitone. Apomorphine (0.5 mg/kg s.c.) given 2 h after haloperidol partially reversed the increase in DOPAC produced by haloperidol. The results suggest care needs to be exercised in the choice of anaesthetic used for voltammetric studies with pentobarbitone being the least recommended.