scholarly journals Effect of anti-thyroid peroxidase (TPO) antibodies on TPO activity measured by chemiluminescence assay

1997 ◽  
Vol 43 (8) ◽  
pp. 1392-1396 ◽  
Author(s):  
V Kaczur ◽  
Gy Vereb ◽  
I Molnár ◽  
G Krajczár ◽  
E Kiss ◽  
...  
Keyword(s):  
Western Blotting ◽  
Competitive Inhibition ◽  
High Sensitivity ◽  
Inhibitory Effect ◽  
Thyroid Peroxidase ◽  
Chemiluminescence Detection ◽  
Chemiluminescence Method ◽  
Blotting Technique ◽  
Hypothyroid Patients

Abstract A chemiluminescence method was developed to measure thyroid peroxidase (TPO) activity and the inhibitory effect of anti-TPO antibodies in purified porcine TPO. The TPO preparation was characterized kinetically and controlled by Western-blotting technique. The chemiluminescence method proved to be reproducible and much more sensitive than the widely used guaiacol method, being able to detect TPO concentrations of 2.21 × 10−5 g/L vs 6.63 × 10−2g/L with the latter. Otherwise, the determinations with the two methods correlated well (r = 0.76). Investigating the effect of IgGs from 23 hypothyroid patients on measured TPO activity, we detected inhibition in 19 cases with the chemiluminescence technique (15 with the guaiacol method). Anti-TPO antibodies showed competitive inhibition of TPO activity with respect to the substrate guaiacol. In both systems, the inhibition is present in the IgG F(ab′)2 fragment. We conclude that the high sensitivity of chemiluminescence detection allows routine determination of the inhibition of TPO activity by anti-TPO antibodies.

scholarly journals High-Sensitivity Determination of Emetine Dithiocarbamate Copper(II) Complex Using the Electrogenerated Chemiluminescence Detection of Tris(2,2'-bipyridine)ruthenium(II).

1997 ◽  
Vol 13 (4) ◽  
pp. 639-642 ◽  
Author(s):  
Kazuhiko TSUKAGOSHI ◽  
Kazuhide MIYAMOTO ◽  
Eiji SAIKO ◽  
Riichiro NAKAJIMA ◽  
Tadashi HARA ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Electrogenerated Chemiluminescence ◽  
Chemiluminescence Detection

scholarly journals Determination of Kinetic Parameters and The Effect of Ion Mg2+ Inhibition Into Pectinase Activities.

2020 ◽  
Vol 4 (2) ◽  
pp. 112
Author(s):  
Dian Puspita Anggraini ◽  
Devita Sulistiana ◽  
Dwi Kameluh Agustina ◽  
Almira Ulimaz
Keyword(s):  
Kinetic Parameters ◽  
Acid Content ◽  
Galacturonic Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Inhibition Constant ◽  
Activity Test ◽  
Pectinase Activity ◽  
Substrate Hydrolysis

The purpose of study was to determine kinetic parameters and inhibitory effect of Mg2+ ions on pectinase. Activity test performed at pH 4,5 temperature 55oC for 50' with 10 mm concentrations of each ion 0-10mm. Galacturonic acid content, as product of pectin substrate hydrolysis, was used as basis for determining activity and analyzed by visible spectrophotometry. At concentrations 2 and 4 mm Mg2+ act as an activator, but at concentrations 6, 8, and 10 mM as inhibitors. The value of KM with and without inhibitors is almost same, that is 0.3145% and 0.3105% but value of Vm from both are different, that is 80,645 μg.ml-1.minute-1 and 62,112 μg.ml-1.minute-1. The conclusion that type of inhibitory pectinase with Mg2+ is a non-competitive inhibition. The inhibition constant value (Ki) is 26,84.

Determination of risperidone at picogram level in human urine by luminol—H2O2 chemiluminescence

2006 ◽  
Vol 60 (4) ◽  
Author(s):  
X. Xie ◽  
X. Shao ◽  
Z. Song
Keyword(s):  
Flow Injection ◽  
Human Urine ◽  
High Sensitivity ◽  
Chemiluminescence Method ◽  
Synergistic Enhancement ◽  
Relative Standard ◽  
Sensitive Determination ◽  
Flow Injection Chemiluminescence ◽  
Simple Flow

AbstractA simple flow-injection chemiluminescence method with synergistic enhancement has been investigated for the rapid and sensitive determination of antipsychotic risperidone. The synergistic action was significant in the chemiluminescence system of luminol—hydrogen peroxide with risperidone as an enhancer. The increased chemiluminescence intensity was correlated with risperidone concentration within the range from 10 pg mL−1 to 1.0 ng mL−1 with relative standard deviations lower than 5.0 % and the detection limit of 4 pg mL−1. At a flow rate of 2.0 mL min−1, the flow-injection chemiluminescence method exhibited both a high sensitivity and excellent selectivity giving a throughput of 120 times per hour. The proposed method was successfully applied to determine the risperidone content in human urine without any pretreatment. It was found that the excretive amounts of risperidone reached their maximum after taking 2.0 mg of risperidone for 1 h, with a total excretive ratio of 17.37 % in 8.5 h.

A chemiluminescence method for the determination of mercury(ii) ions by tuning the catalytic activity of gold nanoparticles with ethylenediamine

2019 ◽  
Vol 11 (10) ◽  
pp. 1317-1323 ◽  
Author(s):  
Meiling Wang ◽  
Yafang Kong ◽  
Ying Li ◽  
Yongxin Huang ◽  
Aiping Fan
Keyword(s):  
Gold Nanoparticles ◽  
Catalytic Activity ◽  
Detection Method ◽  
Chemiluminescence Detection ◽  
Chemiluminescence Method ◽  
Turn On ◽  
Mercuric Ions

A turn-on and an ultrasensitive chemiluminescence detection method for mercuric ions was developed.

scholarly journals An Overview of Optical and Electrochemical Sensors and Biosensors for Analysis of Antioxidants in Food during the Last 5 Years

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1176
Author(s):  
Maryam Nejadmansouri ◽  
Marjan Majdinasab ◽  
Gilvanda S. Nunes ◽  
Jean Louis Marty
Keyword(s):  
Electrochemical Sensors ◽  
High Sensitivity ◽  
Inhibitory Effect ◽  
Ease Of Use ◽  
Practical Applications ◽  
User Friendly ◽  
Analytical Approaches ◽  
Review Current

Antioxidants are a group of healthy substances which are useful to human health because of their antihistaminic, anticancer, anti-inflammatory activity and inhibitory effect on the formation and the actions of reactive oxygen species. Generally, they are phenolic complexes present in plant-derived foods. Due to the valuable nutritional role of these mixtures, analysis and determining their amount in food is of particular importance. In recent years, many attempts have been made to supply uncomplicated, rapid, economical and user-friendly analytical approaches for the on-site detection and antioxidant capacity (AOC) determination of food antioxidants. In this regards, sensors and biosensors are regarded as favorable tools for antioxidant analysis because of their special features like high sensitivity, rapid detection time, ease of use, and ease of miniaturization. In this review, current five-year progresses in different types of optical and electrochemical sensors/biosensors for the analysis of antioxidants in foods are discussed and evaluated well. Moreover, advantages, limitations, and the potential for practical applications of each type of sensors/biosensors have been discussed. This review aims to prove how sensors/biosensors represent reliable alternatives to conventional methods for antioxidant analysis.

Effects of Dipyrone on Prostaglandin Production by Human Platelets and Cultured Bovine Aortic Endothelial Cells

1983 ◽  
Vol 49 (02) ◽  
pp. 132-137 ◽  
Author(s):  
A Eldor ◽  
G Polliack ◽  
I Vlodavsky ◽  
M Levy
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Competitive Inhibition ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Ionophore A23187 ◽  
Aortic Endothelial Cells ◽  
Bovine Aortic Endothelial Cells ◽  
Aortic Endothelial

SummaryDipyrone and its metabolites 4-methylaminoantipyrine, 4-aminoantipyrine, 4-acetylaminoantipyrine and 4-formylaminoan- tipyrine inhibited the formation of thromboxane A2 (TXA2) during in vitro platelet aggregation induced by ADP, epinephrine, collagen, ionophore A23187 and arachidonic acid. Inhibition occurred after a short incubation (30–40 sec) and depended on the concentration of the drug or its metabolites and the aggregating agents. The minimal inhibitory concentration of dipyrone needed to completely block aggregation varied between individual donors, and related directly to the inherent capacity of their platelets to synthesize TXA2.Incubation of dipyrone with cultured bovine aortic endothelial cells resulted in a time and dose dependent inhibition of the release of prostacyclin (PGI2) into the culture medium. However, inhibition was abolished when the drug was removed from the culture, or when the cells were stimulated to produce PGI2 with either arachidonic acid or ionophore A23187.These results indicate that dipyrone exerts its inhibitory effect on prostaglandins synthesis by platelets or endothelial cells through a competitive inhibition of the cyclooxygenase system.

Atomic absorption determination of Hg (II), Cd (II), and As (III) in natural and waste water after preliminary group preconcentration

2019 ◽  
Vol 85 (2) ◽  
pp. 12-16
Author(s):  
I. V. Saunina ◽  
E. N. Gribanov ◽  
E. R. Oskotskaya
Keyword(s):  
Waste Water ◽  
Atomic Absorption ◽  
High Sensitivity ◽  
Distribution Coefficients ◽  
Neutral Medium ◽  
Atomic Absorption Determination ◽  
Absorption Determination ◽  
Relative Standard ◽  
Preliminary Group

The sorption of Hg (II), Cd (II), and As (III) by natural aluminosilicate is studied. It is shown that the mineral absorbs those toxicants in a rather wide pH range, quantitative extraction of analytes being achieved in a neutral or close to neutral medium (pH values range within 7.0 - 8.0; 6.3 - 7.5; 7.4 - 8.5 for Hg (II), As (III), and Cd (II), respectively). The effect of the time of phase contact on the degree of extraction of elements is shown. The sorption capacity of the mineral in optimal conditions of the medium acidity (0.06 mmol/g for mercury, 0.31 mmol/g for cadmium, and 0.52 mmol/g for arsenic) is determined. The distribution coefficients attain values of aboutnX 103-nX 104. A new combined method for determination of Hg (II), Cd (II), and As (III) in natural and waste water is developed and tested. The method consists in a preliminary group sorption concentration of the analytes by aluminosilicate, desorption of the analytes from the surface of the mineral and their subsequent atomic absorption determination. The correctness of the method is verified in analysis of spiked samples. The method is easy to use and exhibits high sensitivity, reproducibility and accuracy of analyte determination. The relative standard deviation does not exceed 0.13. Economic availability and possibility of using domestic sorption materials are the important advantages of the proposed procedure which can be used in the practice of laboratories monitoring the quality and safety of environmental objects.

Determination of Selected Phthalates in Some Commercial Cosmetic Products by HPLC-UV

2020 ◽  
Vol 23 (10) ◽  
pp. 1010-1022
Author(s):  
Emrah Dural
Keyword(s):  
High Performance ◽  
Phthalate Esters ◽  
High Sensitivity ◽  
Hplc Method ◽  
Cosmetic Products ◽  
Limit Of Quantification ◽  
Nail Polish ◽  
Accuracy And Precision ◽  
Butyl Phthalate

Aim and scope: Due to the serious toxicological risks and their widespread use, quantitative determination of phthalates in cosmetic products have importance for public health. The aim of this study was to develop a validated simple, rapid and reliable high-performance liquid chromatography (HPLC) method for the determination of phthalates which are; dimethyl phthalate (DMP), diethyl phthalate (DEP), benzyl butyl phthalate (BBP), di-n-butyl phthalate (DBP), di(2- ethylhexyl) phthalate (DEHP), in cosmetic products and to investigate these phthalate (PHT) levels in 48 cosmetic products marketing in Sivas, Turkey. Materials and Methods: Separation was achieved by a reverse-phase ACE-5 C18 column (4.6 x 250 mm, 5.0 μm). As the mobile phase, 5 mM KH2PO4 and acetonitrile were used gradiently at 1.5 ml min-1. All PHT esters were detected at 230 nm and the run time was taking 21 minutes. Results: This method showed the high sensitivity value the limit of quantification (LOQ) values for which are below 0.64 μg mL-1 of all phthalates. Method linearity was ≥0.999 (r2). Accuracy and precision values of all phthalates were calculated between (-6.5) and 6.6 (RE%) and ≤6.2 (RSD%), respectively. Average recovery was between 94.8% and 99.6%. Forty-eight samples used for both babies and adults were successfully analyzed by the developed method. Results have shown that, DMP (340.7 μg mL-1 ±323.7), DEP (1852.1 μg mL-1 ± 2192.0), and DBP (691.3 μg mL-1 ± 1378.5) were used highly in nail polish, fragrance and cream products, respectively. Conclusion: Phthalate esters, which are mostly detected in the content of fragrance, cream and nail polish products and our research in general, are DEP (1852.1 μg mL-1 ± 2192.0), DBP (691.3 μg mL-1 ± 1378.5) and DMP (340.7 μg mL-1 ±323.7), respectively. Phthalates were found in the content of all 48 cosmetic products examined, and the most detected phthalates in general average were DEP (581.7 μg mL-1 + 1405.2) with a rate of 79.2%. The unexpectedly high phthalate content in the examined cosmetic products revealed a great risk of these products on human health. The developed method is a simple, sensitive, reliable and economical alternative for the determination of phthalates in the content of cosmetic products, it can be used to identify phthalate esters in different products after some modifications.

Sign in / Sign up

Export Citation Format

Share Document