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.     

Colonoscope flexural rigidity measurement

A testing device is developed that determines the stiffness, or flexural rigidity, of an endoscope at specific locations down its length by subjecting it to a compressive axial force, a situation similar to the actual forces applied to the endoscope during a clinical procedure. The endoscope is made to deform in a similar fashion to a slender buckled column and the force causing this deformation is related to the flexural rigidity using column buckling theory. A direct relationship between the critical load needed to cause buckling and the square of column length L is demonstrated experimentally and is expected theoretically, giving confidence in the application of column buckling theory to endoscope testing. Additional confidence in the validity of the columnbuckling test results is obtained by their similarity to data obtained by subjecting the endoscope to a transverse load, determining deflection, and modelling the endoscope as a bent elastic beam. Several makes and models of endoscopes were tested, with flexural rigidity values typically ranging between 160 to 240 Ncm². The effect of a metal stiffener inserted in an endoscope's accessory channel is quantified, as is the change in flexural rigidity down the insertion shaft of a graded-stiffness endoscope. Significant differences in flexural rigidity were obtained between identical endoscopes, each sharing similar usage histories, indicating the need for flexural rigidity measurements for each individual endoscope of a particular model line, though a more extensive study is required to reliably determine scope-to-scope stiffness variations for a particular model line.     

GABA-immunoreactive neurons and terminals in the cat periaqueductal gray matter: a light and electron microscopic study

Immunocytochemical and electron microscopic methods were used to study the GABAergic innervation in adult cat periaqueductal gray matter (PAG). A mouse monoclonal antibody against γ -aminobutyric acid (GABA) was used to visualize the inhibitory neuronal system of PAG. At light microscopy, GABA-immunopositive (GABA_IP) neurons formed two longitudinally oriented columns in the dorsolateral and ventrolateral PAG that accounted for 36% of the neuronal population of both PAG columns; their perikaryal cross-sectional area was smaller than that of unlabeled (UNL) neurons found in the same PAG subdivisions. At electron microscopic level, patches of GABA immunoreactivity were readily detected in neuronal cell bodies, proximal and distal dendrites, axons and axon terminals. Approximately 35–36% of all terminals were GABA_IP; they established symmetric synapses with dendrites (84.72% of the sample in the dorsolateral PAG and 86.09% of the sample in the ventrolateral PAG) or with cell bodies (7–10% of the sample). Moreover, 49.15% of GABA_IP axon terminals in the dorsolateral and 52.16% in the ventrolateral PAG established symmetric synapses with GABA_IP dendrites. Immunopositive axon terminals and unlabeled terminals were also involved in the formation of a complex synaptic arrangment, i.e. clusters of synaptic terminals in close contact between them that were often observed in the PAG neuropil. Moreover, a fair number of axo-axonic synapses between GABA_IP and/or UNL axon terminals were present in both PAG subdivisions. Several dendro-dendritic synapses between labeled and unlabeled dendrites were also observed in both PAG subdivisions. These results suggest that in the cat PAG there exist at least two classes of GABArgic neurons. The first class could exert a tonic control on PAG projecting neurons, the second could act on those GABAergic neurons that in turn keep PAG projecting neurons under tonic inhibition. The functional implications of this type of GABAergic synapse organization are discussed in relation to the dishinibitory processes that take place in the PAG.     

通过调整脊柱治疗臀上皮神经综合征的临床观察

目的观察通过调整脊柱的方法来治疗臀上皮神经综合征的疗效。方法将65例臀上皮神经综合征患者按就诊顺序随机分为对照组(32例)和治疗组(33例)。对照组患者给予基本手法治疗,治疗组在对照组基础上再给予调整脊柱法。两组均以10次为1个疗程,共2个疗程,治疗结束后比较两组疗效。结果治疗组治愈率为93.94%,对照组为56.25%,治疗组疗效明显高于对照组,且治疗组起效时间明显快于对照组,不易复发。结论通过调整脊柱治疗臀上皮神经综合征疗效明显、安全可行。     

色谱柱参数对盐酸四环素有关物质HPLC分析的影响研究

摘要：目的 分析色谱柱参数对盐酸四环素有关物质HPLC分析的影响，筛选影响关键杂质分离度以及理论塔板数的主要 柱参数。方法 针对《中国药典》2020版中盐酸四环素有关物质检查的色谱条件，使用多个品牌不同型号的色谱柱进行色谱分 析，使用SPSS软件进行模型回归，得到柱参数与目标因子分离度及理论塔板数的回归方程，并用实测值进行验证。结果 色谱 柱参数C是影响杂质4-差向四环素和土霉素分离度(R12)的重要参数，利用柱参数C可快速预测不同色谱柱的相似度，进而筛选 适宜四环素分析的色谱柱；探讨了金霉素理论塔板数(R5N)与柱参数之间的关系，其中参数B2对R5N影响较大。结论 建立柱参 数与色谱分析目标因子之间的联系，为盐酸四环素有关物质测定选择合适的色谱柱提供便利与指导。     

巴戟天中大黄素甲醚的提取、分离和纯化方法研究

目的研究获得高纯度大黄素甲醚的可行性方法。方法先用稀硫酸溶液将蒽醌苷水解成苷元,再用热氯仿将苷元提取出来,用2%NaOH反复萃取将大黄素甲醚从氯仿液中提取出来,用薄层色谱法及层析柱法将大黄素甲醚进行分离纯化,经用丙酮反复多次重结晶可得纯度较高的大黄素甲醚。结果本方法提纯得到的大黄素甲醚的纯度较高。结论该方法操作简单、实用性强、成本低,有推广价值。     

头孢地尼原料及制剂的聚合物杂质分析

目的 建立头孢地尼原料及制剂聚合物杂质的分析方法。方法 分别采用0.1mol/L磷酸盐溶液和氯仿-三乙胺为溶剂,制备头孢地尼降解溶液;采用高效凝胶色谱法(HPSEC, TSK G2000 SWxl)和柱切换-LC/MSn法对头孢地尼降解溶液的弱保留值杂质进行分离和结构鉴定,并评估高效凝胶色谱法分析聚合物杂质的专属性;采用Diamonsil, C18型色谱柱,以0.25%四甲基氢氧化铵溶液(pH5.5)-甲醇-乙腈为流动相进行梯度洗脱,建立头孢地尼聚合物的RP-HPLC分析方法,采用二维色谱法和柱切换-LC/MSn法对其专属性进行分析,并进行方法学验证。结果 在头孢地尼降解物中鉴定出头孢地尼二聚体及其异构体,以及若干小分子杂质;高效凝胶色谱法分离头孢地尼聚合物杂质时,小分子杂质与聚合物杂质共出峰,方法专属性与定量准确性差;RP-HPLC法分析头孢地尼聚合物杂质时,能够检出头孢地尼二聚体及其异构体,头孢地尼三聚体,专属性好。结论 高效凝胶色谱法不能对头孢地尼的聚合物杂质进行有效质控,建立的反相色谱法分析头孢地尼聚合物杂质的专属性良好,可将头孢地尼降解溶液可作为聚合物杂质系统适用性溶液。     

艾纳香石油醚部位化学成分的研究

目的:对黔产艾纳香石油醚部位的化学成分进行研究.方法:采用硅胶、凝胶等柱色谱技术对艾纳香石油醚部位的化学成分进行分离、纯化,再结合核磁共振技术鉴定其化学结构.结果:分离并鉴定了5个化合物,分别为花椒油素(1)、豆甾醇(2)、三十一烷(3)、龙脑(4)、4,22-二烯-3-酮豆甾烷(5).结论:5个化合物均首次从艾纳香石油醚部位分离得到.     

Separation of adeno-associated virus type 2 empty particles from genome containing vectors by anion-exchange column chromatography

Adeno-associated virus (AAV) empty capsids typically co-purify with genome containing AAV2 vectors purified by column chromatography. This study describes a method to remove empty capsids from genome containing vector particles by anion exchange chromatography. The separation is based on the slightly less anionic character of empty particles compared to vectors. Detailed methods to achieve AAV2 vector purification and particle separation using cation exchange resin POROS 50HS followed by anion exchange resin Q-Sepharose^xl are described. Chromatographic separation of AAV2 particles was achieved using gradients based on sodium acetate and ammonium acetate, and was optimal at pH 8.5. Efficient removal of particle surface nucleic acid impurities was found to be important to achieve good particle separation. In a large scale experiment performed using partially purified vector containing a mixture of 1.56 × 10¹⁴ vg and 2.52 × 10¹⁵ empty capsids as a starting material, the optimized anion exchange chromatography method resulted in a vector peak of 1.15 × 10¹⁴ vg containing 0.25 × 10¹⁴ empty capsids, corresponding to 74% vector yield and 86-fold reduction in empty capsids in the vector product.