血清胆碱酯酶水平在脓毒症患者诊断中的应用价值分析

目的分析脓毒症患者胆碱酯酶含量及其与降钙素原的相关性,为早期诊断脓毒症提供一个新的初筛检测敏感性指标。方法选择60例脓毒症患者为观察组,另选择同期非脓毒症患者60例作为对照组,测定两组患者血清胆碱酯酶活性,且测定观察组PCT含量,分析PCT与胆碱酯酶的相关性。结果观察组胆碱酯酶含量明显高于对照组,差异有统计学意义(P0.05);胆碱酯酶与降钙素原呈现一定线性相关,相关性曲线为:y=2 325.23 x+239 882.3(r=0.843)。结论血清胆碱酯酶结果与降钙素原呈现一定线性关系,可考虑用于早期评估脓毒症及预后情况。     

Conductimetric Measurement of Cholinesterase Inhibition by Some Pesticides

Abstract

In this present work, we have applied the conductimetric method to measure cholinesterase inhibition by pesticides.

When using acetylcholine as a substrate, we have demonstrated, that for a given incubation of 40 mn, the initial rate of the enzymatic hydrolysis can be related to pesticide concentration. In a given inhibitor concentration range, the activity/log (concentration) relationship is linear and may be used for pesticide quantitation.     

Electrochemical Determination of Cholinesterase Activity and Indication of Its Inhibitors Using A Thick-Film Metallized Platinum Electrode

Abstract

A thick-film metallized platinum electrode operated in the voltammetric mode is used to determine the cholinesterase activity in human serum and erythocytes. Inhibitors of the enzyme can also be quanitified by the electrode with cholinesterase either immobilized directly on the electrode surface or dissolved in the test medium.     

A Prospect for the Analysis of Species Acting as Enzyme Inhibitors as Illustrated by Heavy Metal Inhibition

Abstract

A flow system incorporating an amperometric glucose oxidase enzyme electrode has been used to study the inhibitory effects of 16 metal cations on glucose oxidase. Only copper(II), mercury(II) and silver(I) caused any significant inhibition. the enzyme electrode could be reactivated by EDTA, the reactivation being most effective for copper(II) and least so for silver(I). Other complexing agents were tried for reactivation but proved to be unsatisfactory.

The ability to reactivate the enzyme on the electrode following copper(II) inhibition, and the linear response of the system to the level of this inhibitor according to I/A = -9.49 × 10^?7 log([Cu]/M) + 4.84 × 10^?8; r = 0.994 between 2.5 × 10^?4M and 5 × 10^?3M [Cu]²⁺ indicates a prospect for the use of a flow system for determining enzyme inhibitors in samples.     

A Fluorometric Enzyme Inhibition Detector for Carbamate Pesticide Analysis by High Speed Liquid Chromatography

Abstract

A fluorometric enzyme inhibition detector has been developed for the detection of carbamate pesticides after separation using high speed liquid chromatography.

Housefly head cholinesterase was found to have the greatest sensitivity toward the carbamates, together with horse plasma and bovine erythrocyte cholinesterases. The substrate N-methyl indoxyl acetate is used for monitoring of enzyme activity.     

Analysis of Non-Competitive Enzyme Inhibitors by Thermometric Titrimetry

Abstract

A new thermometric method for the analysis of non-competitive enzyme inhibitors has been developed. Advantages and basic requirements of the method are discussed. In the case studied, 30 nanograms of silver ions were detected.     

Outlining In Vitro and In Silico Cholinesterase Inhibitory Activity of Twenty-Four Natural Products of Various Chemical Classes: Smilagenin,Kokusaginine, and Methyl Rosmarinate as Emboldening Inhibitors

Cholinesterase (ChE) inhibition is an important treatment strategy for Alzheimer’s disease (AD) as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are involved in the pathology of AD. In the current work, ChE inhibitory potential of twenty-four natural products from different chemical classes (i.e., diosgenin, hecogenin, rockogenin, smilagenin, tigogenin, astrasieversianins II and X, astragalosides I, IV, and VI, cyclocanthosides E and G, macrophyllosaponins A-D, kokusaginin, lamiide, forsythoside B, verbascoside, alyssonoside, ipolamide, methyl rosmarinate, and luteolin-7-O-glucuronide) was examined using ELISA microtiter assay. Among them, only smilagenin and kokusaginine displayed inhibitory action against AChE (IC₅₀ = 43.29 ± 1.38 and 70.24 ± 2.87 µg/mL, respectively). BChE was inhibited by only methyl rosmarinate and kokusaginine (IC₅₀ = 41.46 ± 2.83 and 61.40 ± 3.67 µg/mL, respectively). IC₅₀ values for galantamine as the reference drug were 1.33 ± 0.11 µg/mL for AChE and 52.31 ± 3.04 µg/mL for BChE. Molecular docking experiments showed that the orientation of smilagenin and kokusaginine was mainly driven by the interactions with the peripheral anionic site (PAS) comprising residues of hAChE, while kokusaginine and methyl rosmarinate were able to access deeper into the active gorge in hBChE. Our data indicate that similagenin, kokusaginine, and methyl rosmarinate could be hit compounds for designing novel anti-Alzheimer agents.     

Characterization of the CYP3A4 Enzyme Inhibition Potential of Selected Flavonoids

Acacetin, apigenin, chrysin, and pinocembrin are flavonoid aglycones found in foods such as parsley, honey, celery, and chamomile tea. Flavonoids can act as substrates and inhibitors of the CYP3A4 enzyme, a heme containing enzyme responsible for the metabolism of one third of drugs on the market. The aim of this study was to investigate the inhibitory effect of selected flavonoids on the CYP3A4 enzyme, the kinetics of inhibition, the possible covalent binding of the inhibitor to the enzyme, and whether flavonoids can act as pseudo-irreversible inhibitors. For the determination of inhibition kinetics, nifedipine oxidation was used as a marker reaction. A hemochromopyridine test was used to assess the possible covalent binding to the heme, and incubation with dialysis was used in order to assess the reversibility of the inhibition. All the tested flavonoids inhibited the CYP3A4 enzyme activity. Chrysin was the most potent inhibitor: IC₅₀ = 2.5 ± 0.6 µM, K_i = 2.4 ± 1.0 µM, k_inact = 0.07 ± 0.01 min⁻¹, k_inact/K_i = 0.03 min⁻¹ µM⁻¹. Chrysin caused the highest reduction of heme (94.5 ± 0.5% residual concentration). None of the tested flavonoids showed pseudo-irreversible inhibition. Although the inactivation of the CYP3A4 enzyme is caused by interaction with heme, inhibitor-heme adducts could not be trapped. These results indicate that flavonoids have the potential to inhibit the CYP3A4 enzyme and interact with other drugs and medications. However, possible food–drug interactions have to be assessed clinically.     

新的铬天青B直接光度法测定血清总铁结合力

为建立新的铬天青B直接光度法测定血清总铁结合力（TIBC）,在表面活性剂存在下,用铬天青B（CAB）为显色剂测定了血TIBC。结果表明,该法线性范围0～160μmol／L,平均回收率为99．4％,批内变异系数（CV）和批间变异系数分别为0．020、0．035,与临床检验操作规程推荐的方法比较具有良好的相关性,线性回归方程和相关系数分别为y=1．0033x＋0．4510,r=0．9982;60例健康男性血清TIBC含量为46．2～75．8μmol／L（x±2s）,60例健康女性血清TIBC含量为51．8～76．9μmol／L（x±2s）。用新的铬天青B直接光度法测定血清总铁结合力方法简便、灵敏可靠,适合临床应用。     

以5-Br-PADAP为显色剂计算法测定血清总铁结合力

建立了以5-Br-PADAP为显色剂计算法测定血清总铁结合力(TIBC)的方法,通过测定血清铁和血清未饱和铁(UIBC)含量,以血清铁和血清UIBC含量之和计算血清TIBC含量。该法线性范围0~168μmol/L,平均回收率为100.4%,批内变异系数(CV)和批间变异系数分别为0.031、0.046,与临床检验操作规程推荐的方法比较具有良好的相关性,线性回归方程和相关系数分别为y=0.9978x 1.26,r=0.9745。65例健康男性血清TIBC含量为47.61~76.24μmol/L(x±2s),57例健康女性血清TIBC含量为52.56~77.45μmol/L(x±2s)。以5-Br-PADAP为显色剂计算法测定血清总铁结合力TIBC方法简便、灵敏可靠,适合临床应用。     

以Nitro-PAPS为显色剂计算法测定血清总铁结合力

建立了以2-(5-硝基-2-吡啶偶氮)-5-[N-正丙基-N-(3-磺酸丙基)氨基]苯酚二钠(nitro-PAPS)为显色剂、计算法测定血清总铁结合力(TIBC)的方法,通过测定血清铁和血清未饱和铁(UIBC)含量,以血清铁和血清UIBC含量之和计算血清TIBC含量。该法线性范围0～170μmol/L,平均回收率为101.1%,批内变异系数(CV)和批间变异系数分别为0.033、0.042,与临床检验操作规程推荐的方法比较具有良好的相关性,线性回归方程和相关系数分别为y=1.002 3 x 1.44,r=0.971 21。86例健康男性血清TIBC含量为47.5～76.6μmol/L(x±2 s),70例健康女性血清TIBC含量为52.7～77.6μmol/L(x±2 s)。以nitro-PAPS为显色剂计算法测定血清总铁结合力TIBC方法简便、灵敏可靠,适合临床应用。     

一些抑制剂对脲酶反应速率的影响

利用氨气敏电极研究硝酸镍，磷酸盐及ＥＤＴＡ等酶抑制剂对脲酶分解尿素反应速率的影响以及抑制作用机理。     

血清中微量神经节苷脂的色谱分析

叙述了血清中微量神经节苷脂的色谱分析法,研究了正常人和食道癌患者血清中神经节苷脂的种类及其糖组分。采用薄层色谱和毛细管气相色谱电子捕获技术证实了正常人和食道癌患者的血清中神经节耷脂主要为ＧＭ＿３和ＧＤ＿３。     

360名儿童血铅和血锌的检测及相关性分析

铅和锌是微量元素中对人体特别是儿童的生长发育有很大影响的因素。随机检测了 6间幼儿园 3 60名 3～ 6岁儿童的血锌和血铅含量水平 ,血铅 >0 1 μg/mL的儿童占 2 7 2 2 %。对高铅儿童的血锌水平与血铅正常儿童的血锌水平进行相关性比较 ,在分年龄组的比较中 ,3岁组与 6岁组存在显著性差异 (P <0 0 5 ) ;在分性别的比较中 ,男童的血锌水平存在显著性差异 (P <0 0 5 )。     

脑血栓形成患者血清微量元素含量分析

为了解脑血栓形成与微量元素的关系 ,测定了 1 4例脑血栓形成患者和 1 4例健康成人的血清Zn、Cu、Mn、Mg、Cr的含量。结果显示 ,与健康成人相比 ,脑血栓形成患者的Zn、Cr含量下降 (P <0 0 5或P <0 0 1 ) ,ρ(Zn) /ρ(Cu)比值下降 (P <0 0 0 1 )。提示脑血栓形成时血清微量元素水平有一定的改变。采取措施对体内微量元素进行调控 ,应不失为一种防治脑血栓形成的方法     

三试剂自动分析法测定血清总铁结合力——5-Br-PADAP直接光度法

为建立简便、灵敏的测定血清总铁结合力(TIBC)自动化分析法,在表面活性剂存在下,用2-(5-溴-2-吡啶偶氮)-5-二乙氨基酚(5-Br-PADAP)为显色剂测定血清TIBC。该法线性范围0~180μmol/L,平均回收率为99.71%,批内变异系数(CV)和批间变异系数分别为0.024、0.041,与临床检验操作规程推荐的方法比较具有良好的相关性,线性回归方程和相关系数分别为y=0.994 3x 1.220 6,r=0.996 8。血清TIBC含量测定结果(-x±2s):105例健康男性48.0~76.0μmol/L,98例健康女性血清52.0~76.0μmol/L。可见用5-Br-PADAP三试剂自动化分析法测定血清TIBC方法简便、灵敏可靠,适合临床应用。     

酵母对抑制剂耐受的系统分析

纤维素生产乙醇的关键问题之一是水解产生的抑制性物质对乙醇发酵具有明显的抑制效应,因而引起了国内外研究者的广泛关注.研究发现,在抑制剂存在下,酵母在基因表达水平,蛋白水平和代谢物水平都有相应的耐受响应,且这些响应错综复杂.从系统角度运用组学的方法研究这一体系将有助于全面深入了解酵母的耐受机制.本文综述了系统研究的思路和方法在酵母对抑制剂耐受方面的研究状况;对主要研究手段和成果进行了回顾;并对酵母发酵乙醇系统分析的前景进行了展望.     

酵母对抑制剂耐受的系统分析

纤维素生产乙醇的关键问题之一是水解产生的抑制性物质对乙醇发酵具有明显的抑制效应,因而引起了国内外研究者的广泛关注。研究发现,在抑制剂存在下,酵母在基因表达水平,蛋白水平和代谢物水平都有相应的耐受响应,且这些响应错综复杂。从系统角度运用组学的方法研究这一体系将有助于全面深入了解酵母的耐受机制。本文综述了系统研究的思路和方法在酵母对抑制剂耐受方面的研究状况;对主要研究手段和成果进行了回顾;并对酵母发酵乙醇系统分析的前景进行了展望。     

Towards Conformation-Sensitive Inhibition of Gyrase: Implications of Mechanistic Insight for the Identification and Improvement of Inhibitors

Gyrase is a bacterial type IIA topoisomerase that catalyzes negative supercoiling of DNA. The enzyme is essential in bacteria and is a validated drug target in the treatment of bacterial infections. Inhibition of gyrase activity is achieved by competitive inhibitors that interfere with ATP- or DNA-binding, or by gyrase poisons that stabilize cleavage complexes of gyrase covalently bound to the DNA, leading to double-strand breaks and cell death. Many of the current inhibitors suffer from severe side effects, while others rapidly lose their antibiotic activity due to resistance mutations, generating an unmet medical need for novel, improved gyrase inhibitors. DNA supercoiling by gyrase is associated with a series of nucleotide- and DNA-induced conformational changes, yet the full potential of interfering with these conformational changes as a strategy to identify novel, improved gyrase inhibitors has not been explored so far. This review highlights recent insights into the mechanism of DNA supercoiling by gyrase and illustrates the implications for the identification and development of conformation-sensitive and allosteric inhibitors.     

Fully Enzymatic Colorimetric Assay of Serum and Urine Creatinine Which Obviates the Need for Sample Blank Measurements

Abstract

A fully enzymatic method for the colorimetric determination of serum and urine creatinine is described which does not require sample blank measurements. It is based on the formation of hydrogen peroxide from creatinine in a reaction sequence catalyzed by creatinine iminohydrolase, ATP-dependent 1-methylhydantoinase, N-carbamoylsarcosine amidohydrolase and sarcosine oxidase. The hydrogen peroxide is quantitated with high sensitivity at 546 nm by a chromogenic system consisting of peroxidase, 2′-sulpho-2-methyl-benzthiazolinone hydrazone and 2,4,6-tribromo-3-hydroxy-benzoic acid. Only 20 μL of sample are needed for the assay, the total reaction being complete within 10 min at 25°. Within-run precision gave a CV of 3.1 and 1.6 % at serum creatinine concentrations of 79 and 160 μmol/L, respectively, and the standard curve is linear up to at least 1760 μmol/L. The assay yields results which agree well with those found by both an enzymatic UV-method and an alternate enzymatic colorimetric procedure necesitating sample blank measurements to correct for endogenous creatine.