Prisustvo zearalenona u najčešće uzgajanim sortama pšenice u Srbiji

A total of 45 samples of wheat from three different locations in Vojvodina were analyzed for the presence of zearalenone. Analytical methods based on clean-up by solid-phase extraction (SPE) columns and detection by liquid chromatography were used after validation. Limit of detection for ZEA in wheat was 18.6 μg/kg and the limit of quantification was 56.5 μg/kg. Recovery values ranged between 86% and 97%. The occurrence of ZEA in wheat was rather high with 53.3% of positive samples with the average value of 330 μg/kg. Incidences were found from 68 μg/kg to 1079 μg/kg. Contamination levels were above the established maximum limit for unprocessed cereals, other than maize, in as many as seventeen samples. These results were compared to the results of investigation of deoxynivalenol and fumonisin content, established in our previous work on the same samples. The results obtained were also compared to those of the neighboring countries where the relevant data existed and to the data of previous studies in our country.Na prisustvo zearalenona analizirano je ukupno 45 uzoraka pšenice sa tri različite lokacije u Vojvodini. Korišćene su analitičke metode zasnovane na prečišćavanju ekstrakcijom na čvrstoj fazi, te kvantifikacija tečnom hromatografijom, nakon validacije metode. Granica detekcije za zearalenon u pšenici je iznosila 18,6 μg/kg, a granica određivanja 56,5 μg/kg. Efikasnost metode je bila u opsegu od 86% do 97%. Zearalenon je bio prisutan u 53,3% ispitivanih uzoraka, sa prosečnim sadržajem od 330 μg/kg. Dobijene vrednosti sadržaja zearalenona su bile u opsegu od 68 μg/kg do 1079 μg/kg. U čak sedamnaest uzoraka je pronađena koncentracija ovog toksina koja prevazilazi maksimalni dozvoljeni sadržaj zearalenona u netretiranim žitaricama. Ovi rezultati su upoređeni sa vrednostima sadržaja deoksinivalenola i fumonizina u istim uzorcima dobijenim u našim prethodnim istraživanjima. Rezultati su takođe upoređeni sa dostupnim rezultatima dobijenim u našoj i susednim zemljama tokom prethodnih godina

Heat treatment effect on tocopherols, total phenolics and fatty acids in table olives (Olea europaea L.)

The olive fruits are rich source of oil, vitamins, minerals, organic acids and pigments. The fruits contain high level of bioactive compounds. The aim of this study was to examine the effect of heat treatment on tocopherols, total phenolics and antioxidant activity in green and black olives, as well as their fatty acid composition. The instrumental methods used in this experiment were high performance liquid chromatography (HPLC), gas chromatography with flame ionization detection (GC/FID) and spectrophotometric methods. The results revealed that the β+γ-tocopherols content after the heat treatment had the biggest reduction, which was 68.4% for green and 80.2% for black olives. Also, a significant loss of total phenolic content was observed after heat treatment in green and black olives by 18.6% and 18.4%, respectively, as well as antioxidant activity (decrease up to 28.1%). The most abundant fatty acids in green and black olives were oleic (C18:1), palmitic (C16:0) and linoleic acid (C18:2). The changes in fatty acids composition during the heat treatment occurred mostly at the level of polyunsaturated fatty acids, especially linolenic acid (C18:3) in black olives had the significant reduction (by 57.4%) in relation to the initial quantity. © 2023,Notulae Botanicae Horti Agrobotanici Cluj-Napoca. All Rights Reserved

Age-associated shift in rat dendritic cell T-helper polarizing capacity

Almost all cellular components of innate and adaptive immunity undergo age-related remodeling. The findings on age-related changes in human and mouse dendritic cells (DCs) are conflicting, whereas there is no data on the influence of aging on rat DCs. In attempt to fill this gap, freshly isolated splenic conventional OX62+ DCs from 3- (young) and 26-month-old (aged) Albino Oxford rats were examined for subset composition, cell surface expression of activation markers (CD80, CD86 and CD40 and MHC II molecules) and endocytic capacity using flow cytometric analysis (FCA). In addition, splenic OX62+ DCs isolated from rats of both ages were cultured in the presence or in the absence of LPS. These cells were examined for the activation marker and TNF-α, IL-6, IL-12, IL-23, TGF-β1, IL-10 expression using FCA, and RT-PCR and ELISA, respectively. Moreover, the allostimulatory capacity of OX62+ DCs and allogeneic CD4+ T cell cytokine (IFN-γ, IL-4 and IL-17) production in MLR was quantified using FCA and ELISA, respectively. It was found that aging: i) in OX62+ DCs population leads to a shift in CD4+:CD4- cell ratio towards CD4- cells and ii) influences OX62+ DCs maturation capacity (judging by activation marker expression and efficiency of endocytosis) by affecting action of intrinsic (TNF- α and IL-10) and extrinsic regulatory factor expression. Furthermore, in LPS-matured OX62+ DCs from aged rats TNF-α, IL-12, IL-23 and IL-6 expression was increased, while IL-10 expression was diminished. Moreover, in MLR, OX62+ DCs from aged rats exhibited enhanced Th1/Th17 driving force and diminished allostimulatory capacity

Mikrokvantitativno određivanje kvercetina u čistom i farmaceutski doziranom obliku korišćenjem pulsne perturbacione tehnike

We optimized pulse perturbation technique for quantitative determination of quercetin. As matrix system, the Bray-Liebhafsky oscillatory reaction (BL) generated in flowing and feed stirred isothermal reactor is used. Matrix system is found in nonequilibrium stationary state in the vicinity of bifurcation point, and it displays extreme sensitivity on the change of chosen bifurcation parameter (temperature). Perturbations, provoked by addition to miqroquantites of quercetin cause change in matrix system that is followed potentiometricaly by Pt electrode. Quantitative determination of quercetin, is based on causative relation between maximal potential shift ΔEm, (defined as the difference in potential Pt electrode after the performed perturbation and potential of system in given stationary state) and logarithm concentration of quercetin, cQ. Linear relation, ΔEm = f (logcQ), is obtained for concentrations of quercetin in the range, 6.7×10-9 moldm-3 - 2.7×10-5 moldm-3, in the conditions: [KIO3]o = 5.9×10-2 mol dm-3 [H2SO4]o = 5.5×10-2 mol dm-3, [H2O2]o = 2.0×10-1 mol dm-3, specific flow rate jo = 2.9×10-2 min-1 and temperature θ = 42.9°C. The limit of detection is 1.1×10-9 mol dm-3. The developed kinetic method facilitates determination of quercetin in pure and pharmaceutical dosage form (capsule). Method accuracy (given by "recovery") is 99.5%. The described method is simple sensitive and accurate.Optimizovana je pulsna perturbaciona tehnika za kvantitativno određivanje kvercetina. Kao matrični sistem koristi se Bray-Liebhafsky (BL) oscilatorna reakcija generisana u protočnom i dobromešajućem izotermskom reaktoru. Matrični sistem se nalazi u neravnotežnom stabilnom stacionarnom stanju u blizini bifurkacione tačke i ispoljava izuzetnu osetljivost na promene izabranog bifurkacionog parametra (temperatura). Perturbacije, izazvane dodavanjem mikrokoličina kvercetina, dovode do promena u matričnom sistemu koje se mogu pratiti potenciometrijski korišćenjem Pt elektrode. Kvantitativno određivanje kvercetina, zasniva se na kauzalnoj vezi između promene potencijala, ΔEm, (definisane kao razlika potencijala Pt elektrode nakon izvršene perturbacije i potencijala sistema u datom stacionarnom stanju) i logaritma koncentracije kvercetina, cQ. Linearna zavisnost, ΔEm = f (log cQ) je dobijena za koncentracije kvercetina u opsegu 6,7×10-9 moldm-3 - 2,7×10-5 moldm-3, pri uslovima: [KIO3]o = 5,9×10-2 mol dm-3, [H2SO4]o = 5,5×10-2 mol dm-3, [H2O2]o = 2,0×10-1 mol dm-3, specifičnoj brzini protoka jo = 2,9×10-2 min-1 i temperaturi θ = 42,9°C. Limit detekcije je 1,1×10-9 moldm-3. Razvijeni kinetički postupak omogućava određivanje kvercetina u čistom i datom farmaceutski doziranom obliku (kapsule). Tačnost metode (data "recovery" vrednostima) iznosi 99,5%. Opisana metoda je jednostavna osetljiva i pouzdana

Early postnatal castration affects thymic and thymocyte noradrenaline levels and beta-adrenoceptor-mediated influence on the thymopoiesis in adult rats

The interactions among the nervous, endocrine and immune system were studied by examining: i) thymic and thymocyte catecholamine levels in adult rats castrated (Cx) at postnatal day 3 and ii) effects of 14-day-long propranolol (P) treatment on main thymocyte differentiational molecule expression in adult non-Cx and Cx rat. The results demonstrated that castration in early postnatal period lowers levels of both neurally- and thymocyte-derived noradrenaline in adult rats, and thereby diminishes beta-adrenoceptor-mediated fine tuning of the T-cell differentiation/maturation. In non-Cx rats P affected TCR alpha beta-dependent stages of thymocyte differentiation/maturation decreasing frequency of CD4+8+ double positive (DP) TCR alpha beta(low) low cells entering selection processes and increasing relative number of positively selected DP TCR alpha beta(high) (most likely due to an increased thymocyte surface density of Thy-1 that is involved in negative control of TCR alpha beta-mediated signaling/selection thresholds) and the most mature CD4+8- TCR alpha beta(high) cells (including CD4+25+ regulatory cells). However, in Cx rats P failed to produce any significant changes in thymocyte subset composition. (c) 2006 Published by Elsevier B.V

Sexual dimorphism in the catecholamine-containing thymus microenvironment: A role for gonadal hormones

The study was undertaken to explore whether there were: i) apart from neural and circulatory, some other sources of catecholamines (CAs) in rat thymus and ii) gender-specific differences in thymic CA levels, and if so to elucidate the role of sex steroids in this phenomenon. Tyrosine hydroxylase (TH) immunoreactivity was found in thymocytes and thymic epithelial cells (some of which showed morphological features of nurse cells). The density of CA-synthesizing cells was greater in male than in female rats. Noradrenaline (NA), but not dopamine (DA), was detected in thymocytes. NA and DA levels in thymi, and the NA level in thymocytes, were higher in male rats. To explore the Putative role of sex steroids in this dichotomy in the thymi of adult rats gonadectomized (Gx) or sham-Gx at the age of 30 days the density of TH+ cells and CA levels were measured. Gonadectomy abolished sexual dimorphism in the density of thymic TH+ cells (diminishing their density in male rats) and thymic CA levels (the NA levels were reduced in rats of both sexes and also the DA level in male rats). Therefore, it can be assumed that testicular and ovarian hormones control thymic NA and DA levels via different mechanisms. Moreover, in Gx rats, despite the decrease in the overall thymic NA level, an increase in the thymocyte NA level was found indicating that gonadal hormones exert differential effects on the NA level in distinct thymic cellular compartments. (C) 2007 Elsevier B.V. All rights reserved

Expression of alpha(1)-adrenoceptors on thymic cells and their role in fine tuning of thymopoiesis

The study was undertaken to explore: i) the presence of alpha(1)-adrenoceptors (AR) on thymic lymphoid and non-lymphoid cells and ii) their putative role in T-cell development. The expression of alpha(1)-AR on thymic cells was assessed using both immunohistochemistry and flow cytometric analyses, while their putative role in thymopoiesis was estimated by analyses of thymocyte proliferation and apoptosis, and major thymocyte subset distribution in adult rats subjected to 14-day-long treatment with the alpha(1)-AR blocker urapidil. The presence of alpha(1)-AR was demonstrated on both thymocytes (mainly less mature CD3(-) and CD3(low) cells) and thymic non-lymphoid cells (thymic epithelial cells and CD68-positive cells). Chronic treatment with urapidil increased the thymic weight and thymocyte number. The increase in thymocyte number might, at least partly, be related to an enhanced thymocyte proliferation. In addition, an altered thymocyte subset distribution was observed in these rats. The increase in the percentage of CD4+CD8+ double positive (DP) TCR alpha beta(-) thymocytes was accompanied by the reduction in that of CD4+CD8+ (DP) TCR alpha beta(low) cells, and divergent changes in the percentage of the most mature single positive (SP) TCR alpha beta(high) high thymocytes. In urapidil-administered rats the percentage of CD4+CD8-SP TCR alpha beta(high) thymocytes was increased, while that of the CD4-CD8+ TCR alpha beta(high) was reduced. compared with controls. In addition, proportions of CD4+CD25+ RT6.1- and CD161+TCR alpha beta+ regulatory cells were increased. Collectively, the results indicate that alpha(1)-AR are involved in complex network of neuro-thymic and intrathymic communications that provide fine tuning of both conventional effector and regulatory T-cell development. (c) 2009 Elsevier B.V. All rights reserved

Ovarian hormone withdrawal in prepubertal developmental stage does not prevent thymic involution in rats

The study was undertaken to assess the effects of ovarian hormone withdrawal in prepubertal age on thymopoiesis in 2- (young) and 11-month-old (middle-aged) rats. In ovariectomized (Ox) rats, irrespective of age, thymic weight and cellularity were greater than in age-matched controls, but the values of both parameters exhibited the age-related decline. In addition, although thymopoietic efficiency was increased in both groups of Ox rats when compared with age-matched controls, thymopoiesis exhibited the age-related decline mirrored in the lower numbers of both CD4+ and CD8+ recent thymic emigrants in peripheral blood. This reflected the prethymic changes affecting bone marrow progenitor generation/entry and the thymic alterations encompassing the impaired progenitor progression through early pre-T-cell receptor developmental stages (defined by CD45RC/CD2 expression) and, possibly, a more pronounced decrease in the proliferation of the most mature thymocytes. Apart from the changes at thymocyte level, in Ox rats the age-related alterations in thymic stroma (substantiated in a prominent loss of thymic epithelial cells) were registered. Ovariectomy-induced changes in thymic lymphoid and epithelial component, most probably, influenced each other leading to the increase in thymic expression of interleukin-6 and interleukin-7 mRNAs along with time after ovariectomy. Collectively, the study showed that the withdrawal of ovarian hormones in prepubertal age increases the efficiency of thymopoiesis in young adult rats, but does not prevent decline in thymopoiesis occurring with age

Validation and application of FTIR spectroscopy in raw milk analysis

The aim of this study was to investigate whether FTIR spectroscopy is an accurate and valid technique for the assessment of quality parameters in raw cow's milk: fat, protein, lactose, and total solids. The assessment was based on calibration series and comparison with reference material. Furthermore, it takes into account the results obtained in the inter-laboratory comparisons (proficiency testing). The calibration samples were purchased from the accredited regional reference laboratories. The validation parameters included linearity, accuracy, repeatability, reproducibility, and robustness. The linearity ratio was 0.95%. The biases calculated for the fat, protein, lactose and dry matter were -0.33, 0.31, -0.25, and 0.06 respectively. The F value from the F-test was used to determine the significant differences between two independent sets of the results. The obtained results were as follows: 1.469 for fat, 1.634 for protein, 1.192 for lactose, and 0.528 for dry matter. The intra-laboratory reproducibility calculated as the Horwitz Ratios for all parameters were within the criterion limits (0.5 to 0.8). The data obtained for carry-over were 0.27% for fat, 0.52% for protein, 0.47% for lactose, and 0.47% for dry matter. Based on the obtained results it can be concluded that the FTIR spectroscopy is a reliable instrumental technique for the determination of fat, protein, lactose and total solids in raw cow's milk