筛选试验在检测致病性气单胞菌中的应用

[目的]用分步筛选的方法检测致病性气单胞菌，以简化实验步骤，加快检测速度，减轻工作强度。[方法]初筛项目为氧化酶、无盐、6％NaCl胨水3试验，复筛项目为肌醇、精氨酸双水解酶、靛基质、赖氨酸脱羧酶等4项试验，凡氧化酶、靛基质阳性；无盐生长；6％NaCl胨水不生长；肌醇阴性；精氨酸双水解酶、赖氨酸脱羧酶不定的菌株为疑似气单胞菌，再进一步作系统生化鉴定试验，确定其种类。[结果]13种2024份海产品经初筛，检出疑似气单胞菌2668株，检出率为131．8％，其中542份样品同时检出2种以上疑似气单胞菌，进一步复筛筛去非气单胞菌880株，提高筛选率32．0％，系统生化试验后，确定致病性气单胞菌1667株，符合率为93．2％。[结论]分步筛选检测是一种较实用的过筛分离方法。与常法相比，简化了检测步骤，缩短了检测时间，减轻了工作量，节约了人力、物力，基本上解决了分离难的问题，取得了较满意的效果。     

青霉素V含量测定方法的比较

对青霉素Ｖ的３种含量测定方法即电位滴定法、咪唑法和高效液相色谱法进行了比较，发现虽然由电位滴定法和ＨＰＬＣ测定青霉素Ｖ钾原料、咪唑法和ＨＰＬＣ法测定青霉素Ｖ钾片得到的测定结果具有可比性，但由于ＨＰＬＣ法可将青霉素Ｖ中诸杂质如青霉素Ｖ噻唑酸、对羟基青霉素Ｖ等逐一分开，故更具有专属性。     

Blockade and reversal of 5-Methoxy-N, N-Dimethyltryptamine-induced analgesia following noradrenaline depletion

The acute effects of the 5-hydroxytryptamine agonist, 5-Methoxy-N,N-dimethyltryptamine (5-MeO-DMT), upon pain sensitivity, using shock titration, tail-flick and hot-plate methods, in noradrenaline- and 5-hydroxytryptamine-depleted rats were examined. Noradrenaline depletion, following the systemic administration of N-2-chloroethyl-N-ethyl-2-bromobenzylamine hydrochloride (DSP4, 2 X 50 mg/kg, i.p.), caused a reversal of the analgesic effect of 5-MeO-DMT on shock-titration from hypo- to hypersensitivity, and a total blockade of the antinociceptive effect of 5-MeO-DMT upon pain responses in the hot-plate and tail-flick tests. Pretreatment with either p-chloroamphetamine (2 X 10 mg/kg) or p-chlorophenylalanine (200, 100, 100 mg/kg), that depletes central 5-hydroxytryptamine stores, failed to alter the analgesia caused by acute 5-MeO-DMT. Strong evidence is provided for the effect of central noradrenaline depletion upon the analgesic effect of the 5-HT agonist. These findings suggest an important tonic influence of the noradrenaline system upon the descending spinal 5-HT pathway in rats.     

桂益嗪片、服止宁片含量测定法的改进

服止宁片的含量测定采用分光光度法吸收系数太小(E_(1cm)~(1%)=10.7),采用示波极谱滴定法终点较直观。但用与原料药含量测定方法一致的非水滴定法,可消除某些可能的系统误差。此法简便、可靠。本文报告用适量酒石酸掩蔽消除片剂辅料中硬脂酸镁等碱性辅料的干扰,且无须事先分离提取,可用非水滴定法直接测定片剂的含量。     

多相脂质体139注射液化学稳定性的研究

本文根据多相脂质体139注射液的处方组成及其主要有效成份的结构和性质,设计了利用碘量法测定139注射液中不饱和度(双键氧化)和电导滴定法测定酸度的变化规律,得出包封于脂质体中药物的氧化反应符合零级反应速度方程,载体主要成分的脂键水解反应也符合零级反应速度方程;并求得了多相脂质体139注射液中双键氧化反应与载体成分的水解反应的活化能和反应速度常数;预测了药物贮存期 t_(0.9)~(25℃)=2.63年。同时,本文提出了利用电导滴定曲线确定在缓冲溶液及多种化学成份的复杂体系中弱酸盐滴定终点的新方法。     

Ionization of tyrosine residues in human serum albumin and in it complexes with bilirubin and laurate

Spectrophotometric titration of human serum albumin indicates that ionization of the 18 tyrosine residues takes place between pH 9 and 12.7. A Hill plot indicates that protons dissociate co-operatively from tyrosine residues, in pure albumin between pH 11.0 and 11.4 with a Hill coefficient 1.7, and in the bilirubin-albumin complex between pH 11.2 and 11.7 with a Hill coefficient 1.6. With a stopped-flow technique it is shown that about seven of the tyrosines ionize fast, with rate constants well above 10² s^?1, when pH is suddenly changed from near neutral to pH 11.76. Further residues ionize slowly, with rate constants around 10² s^?1 or less. The N-form of albumin (pH 6) contains one more fast ionizing tyrosine than the B-form of albumin (pH 10). Binding of bilirubin or laurate to the albumin molecule (molar ratio 1:1) transforms one to three of the fast ionizing tyrosines to slowly ionizing.     

Scanning electron microscopy and X-ray diffraction studies of human bone oxalosis

Summary Postmortem scanning electron microscopy of human phalanges in a chronic uremic hemodialysis patient with hyperparathyroidism showed the presence of confluent abnormal rounded formations with a radial rosette-like crystalline pattern in the diaphysis as well as in the epiphyseal part of the bones. These fan-shaped configurations were found either as individual formations within bone trabeculae or as numerous aggregated crystalline deposits replacing large parts of the bone structure. The microdissected content of such large areas submitted to X-ray diffraction analysis revealed the predominant presence of calcium oxalate monohydrate or whewellite with some traces of hydroxyapatite. Oxalate titration analysis indicated the presence of 25% of oxalate, corresponding to 45% in weight of whewellite.     

Thermostability of Human Immunodeficiency Virus (HIV-1) in a Liquid Matrix Is Far Higher than That of an Ecotropic Murine Leukemia Virus

For prevention of HIV infection, which is fatal to man and has no known remedy, sterilization of contaminated materials is particularly important. Before applying any sterilization procedures, they have to be checked by accurately following the kinetics of plaque reduction. Though this is almost self-evident, such studies have been few. Here, a microplaque assay of HIV is established using HPB-ALL human T-cells immobilized on a poly-L-lysine-coated plastic dish. This assay was used to compare the ultraviolet and heat inactivation kinetics of HIV (titrated by this method) with those of Moloney murine leukemia virus (MLV) in a liquid matrix. Though the ultraviolet sensitivities of these viruses were identical (D₁₀=2,800 ergs/mm²), HIV was far more resistant to high temperatures (50°C 70°C) than MLV. This implies that these two viruses have different virion structures, though both are members of retroviridae. The higher thermostability of HIV should be taken into account when HIV-contaminated materials are handled.     

交流示波极谱滴定在药物分析中的应用——Ⅱ.用镉滴定二巯基丁二酸钠

二巯基丁二酸钠(Na-DMS)收载于1977年版中国药典,用间接银量法测定其含量,操作较繁琐、费时。 Na-DMS可以和一些金属离子形成稳定螯合物,它本身又是极谱活性物质,在交流示波极谱图上有敏锐切口(图1)。若用镉盐为滴定剂,用Na-DMS切口的消失指示终点,可直接滴定Na-DMS。测定结果与银量法一致,但比银量法简便。     

磺胺类药物恒电流库仑滴定法

利用磺胺类药物的芳环取代反应,以恒电流库仑滴定法测定其含量,方法简便、快速,精密度和准确度均较好,取得了满意的结果。