Study of Polonium (210Po) Activity Concentration in Fruit Wines Derived from Different Locations in Poland.

This study aimed at assessing the activity concentration and the annual effective dose of polonium-210 (210Po) in fruit wines derived from four locations in Poland (Warmian−Masurian, Podlaskie, Lubelskie and Malopolskie voivodeships). The fruit wines differed significantly (p < 0.05) in 210Po activity depending on the production site, with the Malopolskie site having the highest activity (61.4−221.4 mBq/L) and the Podlaskie having the lowest (3.5−97.1 mBq/L). The site differentiation was due to environmental conditions­soil parameters (uranium concentration), precipitations and terrain characteristics, e.g., the proximity of the lakes. The increased activity concentration of 210Po in samples from Malopolska compared with the other sites probably derived from the environment polluted with aqueous wastes and particulate air pollution. The annual effective dose due to the ingestion of fruit wines ranged from 0.112 to 1.214 µSv/year. These levels of exposure are safe according to the WHO criterion (0.1 mSv per year for ingestion) and to the IAEA reference level for public exposure including food (1 mSv per year). Summing up, the data obtained provide information on the activity concentration of 210Po in fruit wines and increase databases on the natural radioactivity of foodstuffs. Future work is needed to examine 210Po activity in samples from all vineyard regions in Poland.

Comparative studies on vitamin B1 deficiency inwholeblood of chronically haemodialysed patients: chromatographic, fluorimetricandPCAstudy.

The levels of thiamine diphosphate (ThDP), the most active biologically form of vitamin B1, were assessed in whole blood oflong-term haemodialysed patients (n = 50), by applying chromatographic methods based on RP-HPLC technique with isocratic elution and fluorescence detection. The target analyte, thiochrome diphosphate (ThODP), was obtained by pre-column derivatization of vitamin B1 contained in blood samples, applying deproteination with trichloroacetic acid, following by oxidation with alkaline solution of potassium ferricyanide(III) and stabilization with DTT before assays. A simple and sensitive assay was developed, and the results were referenced to the commercially available test. Steady-state and time-resolved studies on emissive properties of ThODP enabled optimization of the proposed assay. The F-Snedecor test shown no statistically significant differences between both approaches. Assessed parameters of the proposed assay, such as linearity, precision, sensitivity, and recovery, were satisfactory if compared to the reference one. The LOQ value for ThDP in whole blood of studied group of patients was of 0.5 ng/mL and the recovery of88%. The results disclosed high individual variabilities in the interdialytic deficiencies of ThDP among the patients - ranged from afew percent to values close to 100%. A comprehensive clinical data, characterizing patients under study, were processed together, and analysed by employing achemometric discriminative tool, the Principal Components Analysis,to find interdependences among clinical data characterizing patients. The three Principal Components were disclosed, that in sum explained almost 50% of the observed variability of the clinical data set. Among the clinical parameters involved in PCs were dialyzer membrane and type, duration as well as levels of creatinine, haemoglobin, and red blood cells in patients' whole blood.

Dihydroxy-Substituted Coumarins as Fluorescent Probes for Nanomolar-Level Detection of the 4-Amino-TEMPO Spin Label.

This paper reports on dihydroxycoumarins as fluorescent probes suitable for the detection and determination of the nitroxide radical, namely 4-amino-TEMPO. Since 4-amino-TEMPO is used as a spin label for the detection of various radicals and damage caused by these species, its determination under physiological conditions might help us to understand the mechanism of the oxidative stress. Among different coumarins studied, only dihydroxy-substituted derivatives show high sensitivity, specificity, and selectivity for the nitroxide radical. In this assay, dihydroxy-substituted coumarins under the action of 4-amino-TEMPO show a very fast and significant increase in fluorescence intensity and lifetime. Among them 6,7-dihydroxycoumarin (esculetin) exhibits the strongest fluorescence enhancement (up to 40 times), with an estimated limit of detection equal to 16.7 nM-a significantly lower value when compared with UV-Vis or electron paramagnetic resonance (EPR) spectroscopy. The method is characterized by an easy procedure of sample preparation and very short time of analysis. The mechanism of the interaction between 6,7-dihydroxycoumarin and 4-amino-TEMPO has been examined with the use of a series of complementary techniques, such as steady-state and time-resolved fluorescence spectroscopy, UV-Vis spectroscopy, electron paramagnetic resonance spectroscopy, potentiometric titration, and high-performance liquid chromatography. It has been proven that the only route of the reaction in the system studied is a proton transfer from the molecule of esculetin to the amino group of the nitroxide. Biological studies performed on prostate cancer cells, breast cancer cells, and normal skin fibroblasts revealed significant anticancer properties of 6,7-dihydroxycoumarin, which caused a considerable decrease in the viability and number of cancer cells, and affected their morphology, contrary to normal fibroblasts. Furthermore, the experiment performed on prostate cancer cells showed that fluorescence emission of esculetin is closely related to intracellular pH-the higher pH, the higher observed fluorescence intensity (in accordance with a chemical experiment). On the other hand, the studies performed in different pH levels revealed that when pH of the solution increases, the observed fluorescence intensity enhancement under the action of 4-amino-TEMPO decreases (better sensing properties of esculetin towards the nitroxide in lower pH).

On the use of acridinium indicators for the chemiluminescent determination of the total antioxidant capacity of dietary supplements.

Acridinium salts, due to their chemiluminogenic properties, have found several applications in biomedical analysis as labels and indicators, where the assessment of emission intensity is used for the end-point detection. This work presents the use of chemiluminescent indicators in the form of selected acridinium esters in order to determine the antioxidant properties of exemplary formulations, namely quercetin, vitamin C and the dietary supplement, Apiextract. The principle of measurements is based on a change in the kinetics of emission decay derived from the acridinium cations in alkaline solutions of hydrogen peroxide in the presence of an antioxidant (the analyte). The proposed system makes a beneficial alternative to related methods, which mostly rely on the assessment of emission efficiency and use the luminometric standard luminol - due to superior parameters of acridinium chemiluminescence, among others - high temporary emission efficiency. The features of the proposed method are manifested by a shorter time period of analysis and lower background signals associated with the environmental influences, as compared to typical approaches. The chromatographic (RP-HPLC) analyses of the substrates and products generated during chemiluminogenic oxidation of acridinium cations under assay conditions are also presented.

Thiamine Diphosphate Status and Dialysis-Related Losses in End-Stage Kidney Disease Patients Treated with Hemodialysis.

AIM: (1) To describe the whole blood content of thiamine diphosphate (TDP), a biologically active form of vitamin B1 in end-stage kidney disease patients treated with hemodialysis (HD); (2) to establish the impact of a single HD procedure on TDP blood concentrations; and (3) to describe potential explanatory variables influencing TDP dialysis related losses, including dialysis prescription, vitamin B1 dietary intake and supplementation. METHODS: Single-center, cross-sectional study in 50 clinically stable maintenance HD patients. The assessment of whole blood TDP with the High Performance Liquid Chromatography method, before and after a single, middle-week dialysis session and analysis of clinical and laboratory parameters potentially influencing TDP status Results: We report a significant difference in TDP levels before and after HD sessions - 42.5 (95% CI 38.7-46.2) µg/L and 23.6 (95% CI 18.9-28.2) µg/L, respectively (p = 0.000). The magnitude of intradialytic TDP changes is highly variable among individuals and is negatively associated only with the body weight of the patients (p < 0.013). Vitamin B1 dietary intake and supplementation do not influence whole blood TDP and dialysis-related loss of TDP. CONCLUSIONS: TDP, a bioactive compound of vitamin B1, is substantially lost during the HD procedure, and the magnitude of its loss is associated with the patient's body weight but it is not influenced by vitamin B1 dietary intake and standard supplementation dose.

The development of 1,3-diphenylisobenzofuran as a highly selective probe for the detection and quantitative determination of hydrogen peroxide.

1,3-Diphenylisobenzofuran (DPBF) has been developed as a selective probe for the detection and quantitative determination of hydrogen peroxide in samples containing different reactive nitrogen and oxygen species (RNOS). DPBF is a fluorescent probe which, for almost 20 years, was believed to react in a highly specific manner toward some reactive oxygen species (ROS) such as singlet oxygen and hydroxy, alkyloxy or alkylperoxy radicals. Under the action of these individuals DPBF has been rapidly transformed to 1,2-dibenzoylbenzene (DBB). In order to check if DPBF can act as a unique indicator of the total amount of different RNOS, as well as oxidative stress caused by an overproduction of these individuals, a series of experiments was carried out, in which DPBF reacted with peroxynitrite anion, superoxide anion, hydrogen peroxide, hypochlorite anion, and anions commonly present under biological conditions, namely nitrite and nitrate. In all cases, except for hydrogen peroxide, the product of the reaction is DBB. Only under the action of H2O2 9-hydroxyanthracen-10(9H)-one (oxanthrone) is formed. This product has been identified with the use of fluorescence spectroscopy, NMR spectroscopy, high performance liquid chromatography coupled with mass spectrometry, infrared spectroscopy, elemental analysis, and cyclic voltammetry (CV). A linear relationship was found between a decrease in the fluorescence intensity of DPBF and the concentration of hydrogen peroxide in the range of concentrations of 0.196-3.941 mM. DPBF responds to hydrogen peroxide in a very specific way with the limits of detection and quantitation of 88 and 122.8 µM, respectively. The kinetics of the reaction between DBBF and H2O2 was also studied.