Search

The extracellular vesicles (EVs) released by plant pathogens of the Pectobacterium genus were investigated. The isolates were obtained using differential centrifugation followed by filtration and were characterized in terms of total protein content and particle size distribution. The transmission electron microscopy (TEM) analysis revealed the presence of two morphologically differentiated subpopulations of vesicles in the obtained isolates. The proteomic analysis using matrix-assisted laser desorption ionization mass spectrometry with time of flight detector (MALDI-TOF/TOF-MS) enabled to identify 62 proteomic markers commonly found in EVs of Gram-negative rods from the Enterobacteriaceae family. Capillary electrophoresis (CE) was proposed as a novel tool for the characterization of EVs. The method allowed for automated and fast (<15 min per sample) separation of vesicles from macromolecular aggregates with low sample consumption (about 10 nL per analysis). The approach required simple background electrolyte (BGE) composed of 50 mM BTP and 75 mM glycine (pH 9.5) and standard UV detection. The report presents a new opportunity for quality control of samples containing EVs., Competing Interests: Declaration of Competing Interests The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2020. Published by Elsevier B.V.)

Local differences in structural properties of biological specimens pose a major limitation to quantitative X-ray fluorescence imaging. This is because both the various tissue compartments of different density and variation in the sample thickness upon frequently used freeze-drying come up with the different values of the sample mass per unit area to be taken into account. Even though several solutions to tackle this problem based on the home-made standards for quantification in terms of thickness- and density-independent elemental mass fractions have been proposed, this issue is not addressed enough due to the samples' heterogeneity. In our recent study, we propose a calculation scheme based on combined external-standard micro X-ray fluorescence (micro-XRF) imaging and internal-standard total reflection X-ray fluorescence (TXRF) analysis to determine the corrected elemental mass fraction distributions in commonly analysed rat tissues: kidney, liver and spleen. The results of TXRF analysis of digested large tissue sections together with the mean values of elemental masses per unit area obtained with micro-XRF were employed to determine the average masses per unit area of the samples. The correction for variation of the tissue thickness and density was done through with the use of Compton intensities. Importantly, by its versatility, our novel approach can be used to produce elemental contrast in a variety of biological specimens where local variations in either the sample density or thickness are no longer the issue., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Titanium is widely used both in food and cosmetics, as well as in surgery and industry. Contrary to most studies, the present work focused on the determination of the toxicokinetic parameters of titanium in ionic form, as well as on its tissue biodistribution in rats. The animals were administered either a single intravenous dose of 6 mg Ti/kg b.w., or received the same dose orally every day for 30 days. The concentration of titanium in the serum and organs was measured by a graphite furnace atomic absorption spectrometry. Metal rapidly distributed from the circulation to the investigated organs after both routes of administration, and kidney was identified as the main target tissue, followed by liver and spleen. One month of oral exposure to Ti led to the increase of its concentration in liver, kidneys, spleen, and heart. In the intravenous study, both the highest area under concentration-time curves and the longest elimination half-life time were recorded in the kidney followed by serum, spleen and liver. The present study contributes to the knowledge of the toxicokinetics of titanium in ionic form, which may be especially useful when assessing the health risks of long-term exposure to titanium alloy implants in patients., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Nowadays, studies related to the distribution of metallic elements in biological samples are one of the most important issues. There are many articles dedicated to specific analytical atomic spectrometry techniques used for mapping/(bio)imaging the metallic elements in various kinds of biological samples. However, in such literature, there is a lack of articles dedicated to reviewing calibration strategies, and their problems, nomenclature, definitions, ways and methods used to obtain quantitative distribution maps. The aim of this article was to characterize the analytical calibration in the (bio)imaging/mapping of the metallic elements in biological samples including (1) nomenclature; (2) definitions, and (3) selected and sophisticated, examples of calibration strategies with analytical calibration procedures applied in the different analytical methods currently used to study an element's distribution in biological samples/materials such as LA ICP-MS, SIMS, EDS, XRF and others. The main emphasis was placed on the procedures and methodology of the analytical calibration strategy. Additionally, the aim of this work is to systematize the nomenclature for the calibration terms: analytical calibration, analytical calibration method, analytical calibration procedure and analytical calibration strategy. The authors also want to popularize the division of calibration methods that are different than those hitherto used. This article is the first work in literature that refers to and emphasizes many different and complex aspects of analytical calibration problems in studies related to (bio)imaging/mapping metallic elements in different kinds of biological samples., (Copyright © 2014 Elsevier B.V. All rights reserved.)

A calibration step in an analytical procedure is often not adequately treated, although it is a very important step in the analysis. Also, the approach to the nomenclature seems to be disrespectful. In order to resolve this problem we chose a new classification based on both how the calibration dependence is reconstructed, and how the measurement data is then transformed. In this paper we discussed the steps of a developed calibration procedure in the determination of trace elements in rat brain tissues by the Laser Ablation Inductively Coupled Plasma Time of Flight Mass Spectrometry (LA ICP-TOF-MS) method. The developed calibration procedure uses the long established calibration method - the method of standard addition - although the standard samples are in this case the rat brain tissue samples. The results show the usefulness of the procedure developed in the presented analytical problem related to the analysis of solid samples, which is where the work is original., (© 2013 Elsevier B.V. All rights reserved.)

An ultracentrifugation method was used for the determination of the tacrolimus (FK 506) free fraction in plasma. Samples of 400 microL were centrifuged for 6 h at 160,000 x g, and concentrations of [3H]tacrolimus were measured in the original plasma and in the second layer of the supernatant. The binding of tacrolimus in normal plasma averaged 73% and was independent of the drug concentration. Albumin (3.5%) binding averaged 44.4-57.0%, and alpha 1-acid glycoprotein (100 mg/L) binding averaged 39%. Hepatic transplant patients exhibited 72.0% +/- 3.6% binding of tacrolimus. Plasma protein binding is probably not an important factor in the disposition of tacrolimus.