Circular dichroism detection in high-performance liquid chromatography: Evaluation of the anisotropy factor

The application of a circular dichroism (c.d.) detection system in HPLC using a chiral stationary phase is presented. The simultaneous measurement of the absorbance and c.d. signal allows the evaluation of the anisotropy factor (g = Δ/) and thus the determination of the enantiomeric excess (e.e.) of the eluates. When this detection system is used in preparative chiral chromatography the collection of the enantiomeric fractions can be readily optimized.     

中西医结合治疗LC术后胆囊窝积液58例体会

目的:评价中西医结合治疗与纯西医治疗LC术后胆囊窝积液的临床价值。方法:回顾分析中西医结合治疗58例(A组)与纯西医治疗20例(B组)的临床资料,并比较两组的积液吸收时间、疼痛消失时间、腹胀消失时间、体温正常时间、术后住院天数等指标。结果:A组中在积液吸收时间、腹胀消失时间、术后住院天数方面明显优于B组,差异高度显著(P<0.01);疼痛消失时间、体温正常时间优于B组,差异有显著性(P<0.05)。结论:中西医结合治疗LC术后胆囊窝积液比纯西医治疗,具有疗效快、功能恢复好的优点。     

An automated on-line method for simultaneous analysis of phenothiazines in human serum by high-performance liquid chromatography/sonic spray ionization mass spectrometry using backflush column switching

An automated on-line method for simultaneous analysis of five phenothiazine drugs by high-performance liquid chromatography (HPLC)/sonic spray ionization mass spectrometry (SSI-MS) has been established, using backflush column switching. A 400-μl portion of serum sample diluted 81-fold with distilled water was subjected to the on-line system. In the system, an Oasis HLB cartridge was used as the precolumn for extraction; large molecules such as proteins in serum were discarded by use of distilled water containing 0.1% formic acid as a mobile phase. After switching a valve, the analytes trapped in the precolumn were eluted in the backflush mode and separated by a Chromolith Performance RP-18e column, which is composed of C₁₈-bonded monolithic silica. The column effluents were then introduced into the SSI-MS. The present method provided successful separation and determination of six phenothiazines including an internal standard. Satisfactory linearities, reproducibility, and sensitivity were obtained at concentration levels that matched the toxic levels of phenothiazines. All drug peaks appeared within 18 min, and the system could be reequilibrated in only about 8 min for the next run. Because of the simplicity and rapidness of the method, it is likely to be useful in the fields of emergency medicine and forensic toxicology.     

Localization of substance P- and enkephalin-like immunoreactivity in relation to catecholamine-containing cell bodies in the cat dorsolateral pontine tegmentum: an immunofluorescence study

The distribution of tyrosine hydroxylase-, substance P- and enkephalin-immunoreactive neurons in the cat dorsolateral pons was studied using the indirect immunofluorescence method of Coons. To allow for the visualization of substance P- and enkephalin-immunoreactive cell bodies, colchicine was injected either in the ventricular space or in the cerebral tissue. The distribution of the tyrosine hydroxylase-immunoreactive cell bodies corresponded with the well-known distribution of catecholamine cells in this area of the brain. The observation of adjacent sections treated separately with tyrosine hydroxylase- and enkephalin-antiserum revealed that most catecholaminergic cells contain enkephalin-immunoreactivity. In addition to this catecholamine-enkephalin cell population, a moderate number of substance P-immunoreactive cell bodies was found in dorsolateral pons. The peribrachial nuclei were found to be densely supplied with substance P- and enkephalin-immunoreactive fibers, whereas the medial subdivisions, which contain the majority of the catecholamine cells in the dorsolateral pons, display a moderate number of immunoreactive fibers. These results are suggestive of interactions between peptide-containing and catecholaminergic neurons and also between-peptide-containing and non-catecholamine-containing neurons in the cat dorsolateral pons.     

Membrane properties of rat locus coeruleus neurones

Intracellular recordings were made from neurones in the locus coeruleus contained within a slice cut from rat pons and maintained in vitro. Most neurones fired action potentials spontaneously at frequencies of between 1 and 5 Hz; this did not arise from spontaneous synaptic input but appeared to result from endogenous properties of the membrane conductances. Under voltage clamp at potentials near threshold for action potential generation (? 55 mV) there was a persistent inward calcium current. This current became less with membrane hyperpolarization and was abolished at about ?70 mV. Two potassium currents were observed. The first had properties similar to that generally described as the “fast” potassium current (I_K,A); it flowed transiently (for about 200 ms) when the membrane potential passed from about ?65 to ?45 mV, and was blocked by 4-aminopyridine. The second was a calcium-activated potassium current (I_K,Ca); it flowed for several seconds following a burst of calcium action potentials. Spontaneous and evoked action potentials had both tetrodotoxin-sensitive and tetrodotoxin-resistant components. The latter was apparently due to calcium entry. The potential changes occurring during the spontaneous firing of locus coeruleus neurones could be reconstructed qualitatively from the ionic conductances observed. The membrane properties of the locus coeruleus neurones were remarkably uniform; however, about 5% of cells impaled within the region of the locus coeruleus were electrophysiologically distinct. These atypical cells had short duration action potentials, did not fire spontaneously and had large spontaneous depolarizing synaptic potentials.     

Rhythms, synchrony and electrical coupling in the Locus coeruleus

Electrical coupling of neurones is believed to promote synchronized activity. It may, however, also be a requirement for the maintenance of endogenous rhythmic activity in some systems. In en bloc isolated brainstem-spinal cord of the neonatal rat simultaneous whole cell recordings from pairs of LC neurones (n = 47 pairs) disclosed for the most part strongly synchronized activity which could take the form of tonic spiking or phasic bursts. Simultaneous whole cell recording from LC neurones and glia also revealed synchronized waves of depolarization in 7 of 17 pairs. This synchrony was partly due to respiratory-phased synaptic input and partly due to mechanisms, which were not dependent on chemical synapses. The gap junction uncoupler carbenoxolone suppressed non-synaptic rhythmic activity in LC neurones, but did not suppress either respiratory-phased synaptic input to these neurones or their excitatory response to increased CO(2). We give preliminary direct evidence for the existence of a current pathway between LC neurones, which is inhibited by carbenoxolone. Within the LC nucleus carbenoxolone-sensitive electrical coupling, which may involve neurone-glia as well as neurone-neurone interactions, may be required not just for synchronization, but also for the maintenance of rhythm.     

橐吾属植物中肝毒吡咯里西啶生物碱的LC/MSn检测

目的橐吾属植物中微量成分肝毒吡咯里西啶生物碱(HPA)的检测。方法采用薄层色谱法(TLC)、液相色谱与多级质谱联用法(LC/MSⁿ)。结果对橐吾属22种植物进行了HPA的LC/MSⁿ法检测，其中18种橐吾属植物中检测到了HPA。结论利用LC/MSⁿ法首次检测到东俄洛橐吾等15种橐吾属植物含有不同类型和种类的HPA，应进一步进行提取、分离与鉴定，并研究其毒性与活性；对不同种类、不同来源的橐吾属植物材料应分别检测其HPA。     

液相色谱-质谱测定鸦胆子油脂肪乳注射液在癌症患者体内的血药浓度

目的 建立液相色谱-质谱(LC-MS)法测定癌症患者单剂量滴注鸦胆 子油脂肪乳后体内油酸浓度。方法 用自身对照试验设计,7名癌症患者,第3 天不给药,抽取不同时间点空白血浆样品;第5天,单剂量滴注鸦胆子油脂肪乳 注射液100 mL,滴注开始后,抽取不同时间点血浆样品,60 min滴完,用LC- MS法测定血药浓度。结果 线性范围为2．44-156 mg·L-1;日内、日间变异 系数均<14％;7名癌症患者单剂量滴注鸦胆子油脂肪乳注射液100 mL后,主 要药代动力学参数:tmax=(1．08±0．19)h,Cmax(95．20±29．10)mg·L-1, AUC0-7h=(265．67±59．32)mg·h·L-1,t1／2=(12．14±6．42)h。结论 本法 适用临床测定血浆中油酸浓度。     

高效液相色谱质谱测定肉品中的磺胺二甲嘧啶

〔目的〕用高效液相色谱电喷雾质谱 (ESI -MSn)测定肉品中的磺胺二甲嘧啶。〔方法〕通过多级质谱对阳性样品确证。〔结果〕以二级碎片做定量离子 ,磺铵二甲嘧啶测定线性范围为 (2 5～ 40 0 ) μg L ,最低检出浓度为 5 μg L。〔结论〕方法简便快速 ,检出限低。     

浙江省淡色/致倦库蚊不同地理株对5种常用杀虫剂的抗性调查及防制对策

目的 了解浙江省淡色／致倦库蚊不同地理株对敌敌畏等5种常用杀虫剂的抗性动态，为指导灭蚊工作的深入开展提供科学依据。方法 采用浸渍法，测定Ⅳ龄期幼虫的半数致死浓度（LC50）。结果 浙江省各地淡色／致倦库蚊自然品系对仲丁威和三氯杀虫酯抗性均较低，属低抗水平（RR〈4）；对敌敌畏抗性最高的蚊种主要来自金华、衢州和舟山市，为中等抗性，抗性水平在5．2～6．6倍之间；金华和舟山地区的淡色／致倦库蚊对二氯苯醚菊酯和溴氰菊酯抗性较高，其抗性倍数分别为12．2和12．0倍，属高抗水平。结论 各地理株对5种常用杀虫剂均产生了不同程度的抗性，以二氯苯醚菊酯和溴氰菊酯为最高。