8-羟基喹啉-5-磺酸-溴化十六烷基三甲铵荧光法测定水中铝的探讨

作者根据铝与8-羟基喹啉-5-磺酸(H_2QS)和溴化十六烷基三甲铵(CTMAB)的荧光反应,采用930型荧光计,测定水中铝含量在0～1.5μg/ml范围内有良好线性关系。方法的回收率为87.9％～105.0％,变异系数为2.9％～8.9％,铝的最低检出量和最低检出浓度分别为0.3μg和3×10~(-2)μg/ml。此法适于饮水和天然水中铝含量测定,具有灵敏、准确、所需仪器简单的特点。     

荧光及导数荧光光谱法同时测定维生素B_1,B_2和B_6的含量

本文报道了用荧光法及二阶导数荧光光谱法同时测定多种维生素中维生素B_1,B_2和B_6的含量。用标准曲线法定量,B_1,B_2和B_6的线性范围均为0～5ppm,三者回收率分别为101.4,100.3和99.5%,相对标准偏差分别为2.31,1.33和2.18%.     

Protective Effect of Nifedipine Against Cytotoxicity and Intracellular Calcium Alterations Induced by Acetaminophen in Rat Hepatocyte Cultures

ABSTRACT

Alteration of calcium homeostasis has been proposed to play a major role in cell necrosis induced by a variety of chemical agents such as acetaminophen (APAP). In this study, a potential protective effect of the dihydropyridine calcium channel blocking agent, nifedipine, was investigated in vitro on acetaminophen-induced hepatocyte damage. Rat hepatocytes were exposed during 20 hours to various concentrations of APAP (0.50 to 4.00 mM). The following metabolic and functional parameters were investigated : - lactate dehydrogenase (LDH) release as an indicator of plasma membrane integrity, - cell viability evaluated by the colorimetric MTT assay, and intracellular calcium concentration as evaluated by two fluorimetric methods : a scanning laser cytometer using indo-1-AM as fluorescent probe and a fluorescence plate reader using fluo-3-AM as calcium indicator.

Incubation of hepatocytes with APAP alone in the range 0.50 to 4.00mM resulted in a dose-response relationship with regard to LDH release (243% to 750% of control) and to the loss of cell viability (0 to 67% of control). Moreover these results were correlated with a significant increase in cytosolic calcium content (189 to 406 nM).

Nifedipine treatment prior to APAP exposure, partially prevented LDH release, the plasma membrane blebbing, and thereby the loss of viability. In addition, intracellular calcium level progressively returned within the limits of the control values with increasing concentrations of nifedipine.

It can be concluded that, in in vitro conditions, nifedipine pretreatment exhibits a preventive effect against acetaminophen hepatocyte injury.     

Enzyme-amplified lanthanide luminescence based on complexation reaction--a new technique for the determination of doxycycline

A new spectrofluorimetric method is described for the determination of doxycycline, based on modified enzyme-amplified lanthanide luminescence. Under the optimum conditions, Eu³⁺–doxycycline forms a ternary complex with lysozyme in close proximity and lysozyme can remarkably enhance the characteristic fluorescence intensity of Eu³⁺ at 612 nm in doxycycline–Eu³⁺ binary complex. The enhanced fluorescence intensity is in proportion to the concentration of doxycycline. The limit of detection is 1.28×10⁻⁸ mol l⁻¹, with a linear range from 1.7×10⁻⁷ to 1.7×10⁻⁶ mol l⁻¹. Interferences of other coexisting substances were studied. The developed method was successfully applied to the determination of doxycycline in serum, urine and real samples. The mechanism of fluorescence enhancement was also studied.     

盐酸强力霉素缓释片研究

本文对自制的盐酸强力霉素缓释片进行了研究。测定了体外溶出速率,并用荧光法测定了8名健康受试者单剂量(200mg)口服缓释片(4人)和普通片(4人)(200mg)后的体内血药浓度。实验数据按单室模型并采用TRS-80型计算机和非线性最小二乘法模型嵌合程序进行迭代处理,求得动力学参数。结果表明:缓释片达峰时间较普通片晚2小时,而体内维特有效血浓时间基本相同。9名健康受试者进行的急性胃刺激试验证实:缓释片可减少药物对胃的刺激。     

Determination of myoglobin: comparative evaluation of the new automated VIDAS assay with two other immunoassays

OBJECTIVES: Myoglobin provides the earliest indication of acute myocardial infarction. In this study, the new myoglobin assay for the VIDAS system (bioMérieux) was evaluated. DESIGN AND METHODS: This assay, using an enzyme-linked fluorescent immunoassay (ELFIA) method, was compared with the Olympus immunoturbidimetric method and with another immunometric method (Immulite turbo) using an enzyme-linked chemiluminescent immunoassay (CLIA). RESULTS: The CVs for within-and between-run reproducibility are very similar for the tested methods and acceptable linearity ranges were obtained. No significant interference of hemolysis, turbidity and icteria was observed. In the whole cohort, we obtained decreased values over the entire range of the assay with VIDAS and Immulite turbo methods compared to the Olympus assay; this is probably mainly linked to differences in standards used due to the absence of international standardization of the myoglobin determination. CONCLUSIONS: The new VIDAS myoglobin automated assay provides biologists with a rapid, accurate and reliable determination of myoglobin in plasma samples collected during cardiac workup.     

LVLX—SDS体系的荧光特性及左氧氟沙星的测定

目的研究不同表面活性剂对左氧氟沙星(levofloxacin,LVLX)荧光强度的影响,建立表面活性剂增敏,荧光光度法测定左氧氟沙星含量的新方法。方法比较不同表面活性剂对左氧氟沙星荧光特性的影响,发现在pH6.0的缓冲溶液中十二烷基硫酸钠(SDS)对左氧氟沙星荧光强度有显著的增敏作用,建立SDS增敏,荧光光度法快速测定左氧氟沙星的新方法。结果将该方法用于左氧氟沙星片剂和注射液的测定,结果与国标检测方法高效液相色谱(HPLC)法一致,样品平均回收率为100.4%,RSD为0.64%,检出限为18.9μg/L。结论该方法简便、快捷、准确。     

Fluorometric method based on molecular recognition solid-phase extraction for determination of riboflavin in milk and infant formula

Riboflavin (vitamin B₂) is involved in several biological processes, particularly in energy production, and it is acquired from food ingestion, principally from supplemented food during the first years of life. Therefore, a simple, fast and cost-effective high-throughput method for determination of riboflavin in milk and infant formula is proposed, based on selective extraction using commercially available molecularly imprinted polymers targeted to riboflavin, followed by direct fluorometric determination. Several aspects were studied, namely microplate assay conditions, the composition of eluting solution and the stability of riboflavin in the eluate. Hence, elution using 1% (v/v) acetic acid in methanol or in acetonitrile is recommended, followed by immediate analysis or solvent evaporation, with reconstitution and analysis within 24 h. The proposed method provided a LOD of 0.03 mg L⁻¹, with working range for undiluted samples between 0.125 and 2 mg L⁻¹, and sample throughput of 24 h⁻¹. It was successfully applied to certified reference material NIST-1846 and also to commercial milk and infant formula samples.     

Calcium inhibits catecholamine depletion by reserpine from carotid body glomus cells

Histofluorescent and quantitative microfluorimetric studies have been performed on glomus cells of the rat carotid body, which fluoresce intently after treatment by paraformaldehyde vapor. Reserpine causes a reduction in intensity of fluorescence of about 90%. Subcutaneous injections of calcium chloride (100–300 mg/kg) were given before reserpine. Calcium prevents the depletion of catecholamines from the glomus cells by reserpine. This effect is dose related in that the depletion of catecholamines by heavy reserpine doses (15 mg/kg) cannot be overcome by calcium, medium doses (5 mg/kg) can be overcome but variably, and light doses (1 mg/kg) are always overcome substantially and can result in virtually complete inhibition of the depletion by reserpine. If calcium injections follow reserpine, there is no effect on the depletion of catecholamines. It is speculated that calcium might counteract the effects of reserpine by occupying attachment sites of the vesicular membrane, thereby preventing reserpine from reaching its site of action, resulting in the usual uptake of catecholamines by the vesicles and suppression of the depleting action of reserpine.