Cíl: Porovnání metod stanovení sérového kreatininu (S-Kr) a zhodnocení vlivu použité metody na odhad glomerulární filtrace (eGFR) u dětí s onemocněním ledvin. Metody: S-Kr jsme vyšetřovali u 168 dětí (102 chlapců, věk 1,7–15,9 let) Jaffého metodou a enzymově. GFR byla odhadnuta podle Schwartzova vzorce. Výsledky: Jaffého metoda poskytovala statisticky významně vyšší výsledky S-Kr v nižším koncentračním rozmezí (do 200 μmol/l) a naopak, ve vyšších koncentracích (nad 250 μmol/l) poskytovala výsledky statisticky významně nižší. Do hodnot S-Kr 60 μmol/l Jaffého metodou byly eGFR podle očekávání nižší s vyšším S-Kr ve srovnání s enzymovou metodou. eGFR však byly paradoxně vyšší u všech pacientů se S-Kr nad 100 μmol/l při použití Jaffého metody. Tento paradox byl patrný zejména u dospívajících chlapců, a to především kvůli odlišnému koeficientu F ve Schwartzově vzorci. Závěr: Odhad GFR závisí na přesnosti měření S-Kr a na koeficientu F ve Schwartzově vzorci. Tyto vlivy mohou mít závažné klinické důsledky především u dětí s pokročilým chronickým onemocněním ledvin stadia 4 a 5, kdy enzymová metoda poskytuje významně nižší hodnoty eGFR, což může vyústit v časnější zahájení dialyzační léčby.
Aim: Comparison of methods for determination of serum creatinine (SCr) and evaluation of the effect of the used method on estimation of glomerular filtration rate (eGFR) in children with kidney disease. Methods: We assessed SCr in 168 children (102 boys, age 1.7–15.9 years) by both, the Jaffe method and enzymatically. eGFR was estimated by Schwartz formula. Results: The Jaffe method overestimated SCr at lower levels (< 200 μmol/L) but underestimated it at higher levels (> 250 μmol/L). Up to SCr of 60 μmol/L using Jaffe method, eGFR values were lower with higher SCr in comparison to enzymatic method as expected. However, eGFR values were paradoxically higher in all patients with SCr above 100 μmol/L using Jaffe method. This paradox was especially evident in adolescent boys mainly due to the different F coefficient used for eGFR calculation. Conclusion: Estimation of GFR depends on the accuracy of the SCr measurement and the F coefficient in the Schwartz formula. These effects can have serious clinical consequences, especially in children with advanced chronic kidney disease stages 4 and 5, when the enzymatic method provides significantly lower eGFR values, which may result in earlier initiation of dialysis treatment.
- Klíčová slova
- Jaffého metoda, enzymová metoda, Schwartzův vzoreca,
- MeSH
- dítě MeSH
- klinická studie jako téma MeSH
- kolorimetrie metody MeSH
- kreatinin * analýza krev MeSH
- lidé MeSH
- mladiství MeSH
- Check Tag
- dítě MeSH
- lidé MeSH
- mladiství MeSH
Příspěvek upozorňuje na korelace mezi výsledky instrumentálního měření barevnosti a obsahem některých biologicky aktivních organických látek (karotenoidy, chlorofyl, anthokyaniny, kurkuminoidy aj.) v přírodninách a v produktech přírodního původu. Dostatečně těsné korelace mohou vést po doplnění regresní analýzou a kalibrací k vývoji postupů pro rychlé stanovení obsahu těchto látek a jejich skupin měřením barevnosti bez náročnější úpravy vzorků.
The paper draws attention to the correlations between the results of instrumental colour measurements and the content of some biologically active organic substances (carotenoids, chlorophyll, anthocyanins, curcuminoids, etc.) in natural products and products of natural origin. After supplementation by regression analysis and calibration, sufficiently close correlations can lead to the development of procedures for rapid determination of the content of these substances and their groups by colour measurement without more demanding sample treatment.
- Klíčová slova
- biologicky aktivní látky, měření barevnosti,
- MeSH
- barva MeSH
- chemické techniky analytické * MeSH
- kolorimetrie metody MeSH
Pellets with an immobilized enzyme (acetyl- or butyrylcholinesterase) are the up-to-date type of carriers used for the detection of nerve agents (soman, sarin, tabun, VX, Novichok) and other cholinesterase inhibitors such as organophosphate and carbamate insecticides (parathion, malathion). They are used in the glass detection tubes as a layer containing the enzyme together with the second layer, which contains a colorimetric reagent and substrate. The detection method is based on the visually or spectrophotometrically observable Ellman's reaction, which develops a yellow color in the absence of the cholinesterase inhibitor; otherwise, the detector preserves its original color (preferably white). This reaction occurs very fast and has a high sensitivity to nerve agents but it suffers from an indistinctive color transition from white to yellow. In the presented study, a new approach with the use of the synergic effect of magnesium aluminometasilicate with a high surface area marketed as Neusilin®US2 and a protective semipermeable Eudragit® RL layer was utilized. The prepared pellets have been evaluated for their properties such as the activity of the enzyme, intensity of the developed yellow color, sensitivity to cholinesterase inhibitor physostigmine, which acts as a nerve agent simulant, and physical parameters such as hardness, pycnometric density and sphericity. After the initial evaluation, all samples underwent a stability test under three different storage conditions for 24 months during which they were evaluated at given time points (0, 3, 6, 12 and 24 months). It was found that the prepared samples achieved a much higher intensity of developed yellow color than in the published studies while maintaining similar or better sensitivity, speed of detection and suitable physico-chemical properties.
- MeSH
- acetylcholinesterasa chemie MeSH
- butyrylcholinesterasa chemie MeSH
- časové faktory MeSH
- cholinesterasové inhibitory analýza MeSH
- enzymy imobilizované chemie MeSH
- kolorimetrie metody MeSH
- nervová bojová látka analýza MeSH
- polymery chemie MeSH
- silikáty chemie MeSH
- sloučeniny hliníku chemie MeSH
- sloučeniny hořčíku chemie MeSH
- Publikační typ
- časopisecké články MeSH
Serum bactericidal test represents an alternative possibility for optimization of antibiotic treatment. The paper aimed to confirm non-inferiority of bactericidal testing using the broth dilution method according to the CLSI method (M21A) in comparison with turbidimetric and colorimetric modifications. We tested human blood sera (n = 76) of ten hematological patients, their blood was withdrawn prior to and during the course of antibiotic therapy. Testing employed the reference strain Escherichia coli ATCC 25922. The results of the modified turbidimetric method did not differ in a statistically significant way with the use of the wavelengths of 620 nm or 405 nm and the break-point <30% turbidity change after 24-hour incubation. The colorimetric method was also non-inferior from the CLSI method when resazurin was applied after 8-hour incubation and the results of subculture were read after 24-hour incubation. Both tested modifications can represent a shorter alternative to the CLSI reference method.
- MeSH
- antibakteriální látky farmakologie terapeutické užití MeSH
- časové faktory MeSH
- dospělí MeSH
- Escherichia coli účinky léků MeSH
- kolorimetrie metody MeSH
- lidé středního věku MeSH
- lidé MeSH
- mikrobiální testy citlivosti metody MeSH
- mladý dospělý MeSH
- nefelometrie a turbidimetrie metody MeSH
- senioři MeSH
- sérový baktericidní test metody MeSH
- spektrofotometrie MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- senioři MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
Detection tubes are small devices for the colorimetric enzymatic detection of cholinesterase inhibitors such as sarin, soman, VX nerve agents and substances denoted as Novichok. These detectors contain carriers in the form of pellets with immobilized cholinesterase, substrate and detection reagent. Their advantages are portability, sensitivity and simplicity, enabling fast detection of such compounds from air and water in case of a terrorist attack or war. In general, maintaining the stability of an enzyme for a longer time is very problematic; therefore, its further enhancement is required for safety and financial reasons. In this study, the stability of our patented carriers in the form of pellets with immobilized butyrylcholinesterase containing an increasing amount of the unique sorbent Neusilin® US2 was evaluated. The samples containing Neusilin maintained the stability of the immobilized enzyme for a longer time even at higher temperature and humidity than the currently commercially used carrier without Neusilin, allowing improved detection of nerve agents.
- MeSH
- biosenzitivní techniky metody MeSH
- butyrylcholinesterasa chemie metabolismus MeSH
- cholinesterasové inhibitory analýza MeSH
- enzymy imobilizované chemie metabolismus MeSH
- kolorimetrie metody MeSH
- nosiče léků chemie MeSH
- silikáty metabolismus MeSH
- sloučeniny hliníku metabolismus MeSH
- sloučeniny hořčíku metabolismus MeSH
- stabilita enzymů účinky léků MeSH
- Publikační typ
- časopisecké články MeSH
Vydání první 287 stran : ilustrace (některé barevné) ; 26 cm
Publikace se zabývá procesy tvořící barevný vjem. Věnuje pozornost fotometrii a světlu, teoriím barevného vidění, vzniku a šíření neuronových signálů do mozku. Dále se zabývá kolorimetrií, kolorimetrickými přístroji a metody měření. Učebnice pro odborníky, postgraduální studenty polygrafie i laiky.
- MeSH
- kolorimetrie metody MeSH
- oči - fyziologické jevy MeSH
- světlo MeSH
- vidění barevné MeSH
- vnímání barev MeSH
- Publikační typ
- monografie MeSH
- populární práce MeSH
- učebnice MeSH
- Konspekt
- Optika
- Učební osnovy. Vyučovací předměty. Učebnice
- NLK Obory
- fyzika, biofyzika
- oftalmologie
Colorimetric biosensors of cholinesterase inhibitors are ideal for fast, reliable, and very simple detection of agents in air, in water, and on surfaces. This paper describes an innovation of the Czech Detehit biosensor, which is based on a biochemical enzymatic reaction visualized by using Ellman's reagent as a chromogenic indicator. The modification basically consists of a much more distinct color response of the biosensor, attained through optimization of the reaction system by using Guinea Green B as the indicator. The performance of the modified biosensor was verified on the chemical warfare agents (sarin, soman, cyclosarin, and VX) in water. The detection limits ascertained visually (with the naked eye) were about 0.001 µg/mL in water (exposure time 60 s, inhibition efficiency 25%).
The main objective of the presented research was to prepare an innovative carrier as a filler for detection tubes in the form of double-coated pellets with a very significant color transition during the detection of cholinesterase inhibitors such as nerve agents, organophosphorus or carbamate insecticides in liquids that is observable visually and also spectrophotometrically at 412 nm. The pellet cores were prepared by the extrusion/spheronization method. Consecutively, two different coats were applied on the pellet cores in the coating device using the Wurster column method. To increase the color change intensity, the second semipermeable coat based on Eudragit® RL was applied on top of the first coat, which was formed by butyrylcholinesterase immobilized in hydroxypropyl methylcellulose. Prepared samples differing in thickness of the second coat were evaluated for their quality parameters, enzymatic activity and inhibition. The detection mechanism was based on the standard Ellman's colorimetric reaction. It was observed that the semipermeable coat prevented leaching of the enzyme into the solution and led to an increased intensity of color transition from white - yellow to white - deep yellow/orange, thus enabling a more accurate visual detection. This system allows easy, rapid and safe identification of cholinesterase inhibitors in liquids, especially chemical warfare agents.
Glucose is a typical marker of diabetes mellitus but it corresponds also with metabolic syndrome, immune disorders and some types of poisoning. Hence fast, low cost and simple method for its determination is required. Bubble wrap, cheap and available material, was used for immobilization of glucose oxidase (GOx) and peroxidase (POx), the enzymes necessary for colorimetric determination of glucose. Method is based on reaction of enzymes (immobilized in sol-gel membrane inside the bubbles) with substrates glucose and o-phenylenediamine dihydrochloride (o-PD) providing intensive coloration. The color change can be easily tracked by phone integrated camera. Color intensity expressed in red-green-blue (RGB) color model was used for displaying of photos and for gaining numeric data representing concentrations of glucose. The assay exerted good correlation of color intensity with the concentration of glucose, adequately low limit of detection (750 mmol/l) for glucose blood assay, no influence of interferents or matrix substances and by sufficient long term stability of sol-gel membrane. The sensor was found as low-cost simple way to analyze glucose blood levels with promising prospects in the field of portable devices.
Magnetic particles (MPs) are currently used as a suitable alternative for peroxidase in the construction of novel biosensors, analytic and diagnostic methods. Their better chemical and thermal stabilities predestine them as appropriate pseudo-enzymatic catalysts. In this point of view, our research was focused on preparation of simply and fast method for immobilization of glucose oxidase onto surface of MPs with peroxidase-like activity. Spectrophotometric method (wavelength 450 nm) optimized for glucose determination using modified MPs has been successfully developed. Concentration curve for optimization of method was assayed, and Michaelis-Menten constant (K m) calculated, maximum reaction rate (V max), limit of detection, and correlation coefficient were determined to be 0.13 mmol/l (2.34 mg/dl), 1.79 pkat, 3.74 µmol/l (0.067 mg/dl), and 0.996, respectively. Interferences of other sugars such as sucrose, sorbitol, deoxyribose, maltose, and fructose were determined as well as effect of substances presenting in plasma (ascorbic acid, reduced glutathione, trolox, and urea). Results in comparison with positive and negative controls showed no interferences of the other sugars and no influence of plasma substances to measuring of glucose. The constructed method showed corresponding results with linear dependence and a correlation coefficient of 0.997. Possibility of repeated use of modified MPs was successfully proved.
- MeSH
- enzymy imobilizované metabolismus MeSH
- glukosaoxidasa metabolismus MeSH
- kolorimetrie metody MeSH
- krevní glukóza metabolismus MeSH
- lidé MeSH
- magnetismus * MeSH
- peroxidasy metabolismus MeSH
- spektrofotometrie MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
