Preexposure to Olive Oil Polyphenols Extract Increases Oxidative Load and Improves Liver Mass Restoration after Hepatectomy in Mice via Stress-Sensitive Genes

Polyphenols can act as oxidants in some conditions, inducing redox-sensitive genes. We investigated the effect of preexposure to the olive oil polyphenols extract (PFE) on time-dependent changes in the hepatic oxidative state in a model of liver regeneration—a process in which oxidative stress associated with the metabolic overload accounts for the early events that contribute to the onset of liver self-repair. Liver regeneration was induced by one-third hepatectomy in mice. Prior to hepatectomy, mice were intraperitoneally given either PFE (50 mg/kg body weight) or saline for seven consecutive days, while respective controls received vehicle alone. Redox state-regulating enzymes and thiol proteins along with the mRNA levels of Nrf2 gene and its targets γ-glutamylcysteine synthetase and heme oxygenase-1 were determined at different time intervals after hepatectomy. The liver mass restoration was calculated to assess hepatic regeneration. The resulting data demonstrate the effectiveness of preexposure to PFE in stimulating liver regeneration in a model of a small tissue loss which may be ascribed to the transient increase in oxidant load during the first hours after hepatectomy and associated induction of stress response gene-profiles under the control of Nrf2

NMR and Chemometric Characterization of Vacuum Residues and Vacuum Gas Oils from Crude Oils of Different Origin

NMR spectroscopy in combination with statistical methods was used to study vacuum residues and vacuum gas oils from 32 crude oils of different origin. Two chemometric metodes were applied. Firstly, principal component analysis on complete spectra was used to perform classification of samples and clear distinction between vacuum residues and vacuum light and heavy gas oils were obtained. To quantitatively predict the composition of asphaltenes, principal component regression models using areas of resonance signals spaned by 11 frequency bins of the 1H NMR spectra were build. The first 5 principal components accounted for more than 94 % of variations in the input data set and coefficient of determination for correlation between measured and predicted values was R2 = 0.7421. Although this value is not significant, it shows the underlying linear dependence in the data. Pseudo two-dimensional DOSY NMR experiments were used to assess the composition and structural properties of asphaltenes in a selected crude oil and its vacuum residue on the basis of their different hydrodynamic behavior and translational diffusion coefficients. DOSY spectra showed the presence of several asphaltene aggregates differing in size and interactions they formed. The obtained results have shown that NMR techniques in combination with chemometrics are very useful to analyze vacuum residues and vacuum gas oils. Furthermore, we expect that our ongoing investigation of asphaltenes from crude oils of different origin will elucidate in more details composition, structure and properties of these complex molecular systems

Kinetic Evaluation of Imidacloprid Degradation in Mice Organs Treated with Olive Oil Polyphenols Extract

Imidacloprid is a highly effective insecticide, acting as agonists at the insect nicotinic acetylcholine receptor. Nevertheless, imidacloprid itself or its metabolites could exhibit toxicity in mammals. Imidacloprid biotransformation involves oxidative cleavage, releasing the 6-chloronicotinic acid. Therefore, the concentration of imidacloprid and 6-chloronicotinic acid was used to characterize degradation kinetics and distribution of imidacloprid in mice liver, kidneys and lungs. Additionally, the influence of olive oil polyphenols on imidacloprid metabolism was evaluated. Experimental animals were divided into three groups: control, IMI – imidacloprid treated mice (5 mg/kg) and (IMI + PP) – mice treated with polyphenols (10 mg/kg) for seven days before the administration of imidacloprid. Neither imidacloprid nor 6-chloronicotinic acid could be detected 48 hours after administration in IMI group, while complete degradation in the (IMI + PP) group was accomplished within 24 hours. Significantly higher rate constant and shorter half-life in (IMI + PP) group emphasize that polyphenols may diminish the toxicity of this pesticide

Sorption and leaching potential of organophosphorus insecticide dimethoate in Croatian agricultural soils

Dimethoate is an organophosphorus insecticide widely used in Croatia and the rest of the European Union, with polar structure and high water solubility that make it prone to leaching. This study investigated how physico- chemical soil properties affected dimethoate sorption and mobility. For that purpose, five soil samples were collected in three Croatian regions (two coastal and one mountain region) and analyzed. Dimethoate sorption process was studied using the batch procedure while its mobility and leaching potential was investigated by column experiment. The results showed that the sorption efficiency of dimethoate can be adequately described by Freundlich model ; all isotherms were of L-type with various degrees of non-linearity, suggesting that soils had different distribution of sorption sites energies. Energy distribution was wider for soils richer in organic matter (OM). KF values indicated relatively low sorption efficiency for all soils, but the increase of KF values was proportional to OM content. In order to determine the mechanisms involved in soil dimethoate sorption and mobility, breakthrough curves (BTCs) were fitted by two mathematical models, namely: one-site equilibrium (ELM) and two-site nonequilibrium sorption model (NELM). Parameters obtained by fitting showed trends that correlated well with OM, humic acid content and CEC. The correlations were quantified using Kendall-Tau statistical test and enabled us to form a model for prediction of leaching potential. A simplified model for dimethoate sorption/transport was also proposed

Sorption and leaching potential of organophosphorus insecticide dimethoate in Croatian agricultural soils

Dimethoate is an organophosphorus insecticide widely used in Croatia and the rest of the European Union, with polar structure and high water solubility that make it prone to leaching. This study investigated how physico- chemical soil properties affected dimethoate sorption and mobility. For that purpose, five soil samples were collected in three Croatian regions (two coastal and one mountain region) and analyzed. Dimethoate sorption process was studied using the batch procedure while its mobility and leaching potential was investigated by column experiment. The results showed that the sorption efficiency of dimethoate can be adequately described by Freundlich model ; all isotherms were of L-type with various degrees of non-linearity, suggesting that soils had different distribution of sorption sites energies. Energy distribution was wider for soils richer in organic matter (OM). KF values indicated relatively low sorption efficiency for all soils, but the increase of KF values was proportional to OM content. In order to determine the mechanisms involved in soil dimethoate sorption and mobility, breakthrough curves (BTCs) were fitted by two mathematical models, namely: one-site equilibrium (ELM) and two-site nonequilibrium sorption model (NELM). Parameters obtained by fitting showed trends that correlated well with OM, humic acid content and CEC. The correlations were quantified using Kendall-Tau statistical test and enabled us to form a model for prediction of leaching potential. A simplified model for dimethoate sorption/transport was also proposed

Aucubin protects against cisplatin-induced acute kidney injury in mice via attenuation of oxidative stress, apoptosis and inflammation

Background: Aucubin is pharmacologically active natural compound which possesses numerous beneficial properties in vitro and in vivo. Purpose: This study aimed to evaluate the protective effect of aucubin against cisplatin (CP)-induced acute kidney injury in mice and the mechanism of its action. In addition, a modulation of CP-induced cyototoxicity was investigated in vitro. Study design: Aucubin was administrated to mice orally (po) and intraperitoneally (ip) (1.5 and 5 mg/kg) for two consecutive days, two days after ip injection of cisplatin (CP), 11 mg/kg. Human cervical cancer HeLa cells were treated with CP 30 µM and aucubin 0–1000 μM. Methods: Hematoxylin and eosin staining, western blot, immunohistochemistry and immunofluorescence were used to evaluate the renoprotective activity of aucubin. The cell viability assay was used to evaluate in vitro cytotoxicity of aucubin. Results: Treatment with aucubin by both routes of administration ameliorated histopathological changes and reduced elevated serum markers of kidney injury. CP administration increased renal expression of HO-1 and 4-HNE, as well as TNF-α, which was dose-dependently ameliorated by the administration of aucubin, indicating the suppression of oxidative stress and inflammation, respectively. Moreover, aucubin reduced increased renal expression of cleaved caspase-3 and -9 and decreased PARP cleavage, suggesting amelioration of CP-induced apoptosis. Mechanistically, aucubin normalized the activation of ERK1/2, PI3K/Akt, FOXO3a, STAT3 and NF-κB signaling in mice kidneys. Aucubin was slightly more successful in the amelioration of kidney injury when administered by ip than by po route. In human cervical cancer cells, aucubin did not modulate the CP cytotoxicity in doses up to 1 mM. Conclusions: The findings of this study show that aucubin acts as a protective agent against CP-induced nephrotoxicity, without interference with the CP anticancer activity in clinically relevant doses

Hysteretic Behavior of Imidacloprid Sorption-Desorption in Soils of Croatian Coastal Regions

Sorption and desorption are important processes that influence the transport, transformation, and bioavailability of imidacloprid in the soils. Equilibrium batch experiments were carried out using six coastal Croatian soils. The equilibrium sorption and desorption experimental data showed the best fit to the Freundlich equation. Sorption parameters predicted with Freundlich model, KFsor and 1/n ranged from 2.92 to 5.74 (mg/kg)/(mg/L)1/n, and 0.888 to 0.919, recpectively. The sorption of imidacloprid was found to be sensitive to organic carbon (OC) content. The highest sorption was observed in Krk soil (OC 4.74%) and the lowest in Zadar soil (OC 1.06%). Fitted desorption parameter values, KFdes were consistently higher than those associated with sorption. The opposite trend was observed for the exponential parameter 1/n. Results also suggested that imidacloprid sorption-desorption by soil is concentration dependent, i.e. at lower imidacloprid concentrations a greater sorption percentage and lower desorption percentage occurred. Desorption studies revealed that there was a hysteresis effect in all the tested soils. Hysteresis coefficient values (H) varied from 0.656 to 0.859. The study results emphasize that the controled application of imidacloprid is obligatory, especially in the soils with a low organic carbon content in order to minimize a risk of environmental and groundwater pollution

Priručnik za seminare i vježbe iz Biokemije II

Priručnik za seminare i vježbe iz Biokemije II namijenjen je studentima medicine Medicinskog fakulteta Sveučilišta u Rijeci. Gradivo je prilagođeno nastavnom planu i programu seminara i vježbi iz kolegija Biokemija II. U praktikumu su obrađene određene kvalitativne i kvantitativne pretrage seruma i urina kako bi studenti viših godina studija mogli lakše pratiti probleme iz područja medicinske biokemije. Studenti će se kroz laboratorijske vježbe upoznati s laboratorijskim tehnikama i metodama kliničkih ispitivanja za utvrđivanje patoloških promjena u organizmu. U priručniku su opisani postupci određivanja aktivnosti dijagnostički značajnih enzima (AST, ALT, CHE, GGT, ALP), koncentracije glukoze u serumu, sastava lipoproteina, koncentracije triglicerida, ukupnog, HDL i LDL kolesterola u serumu, koncentracije željeza i zasićenosti transferina, koncentracije ureje, kreatinina i mokraćne kiseline u serumu odnosno urinu. Nadalje, navedene su metode oralnog testa opterećenja glukozom i određivanja glikiranog hemoglobina. Opisane su kvalitativne reakcije za dokazivanje hemoglobina, bilirubina, ketonskih tijela i nitrita u urinu. Pored toga, eksperimentalne vježbe iz područja enzimske kinetike namijenjene su boljem razumijevaju principa katalitičkog djelovanja enzima, kao i značaja optimalnih uvjeta enzimske aktivnosti kao što su pH i temperatura te mehanizama enzimske inhibicije. Opisane su osnovne analitičke metode koje se koriste u biokemijskim i kliničkim laboratorijima kao što su spektrofotometrija, tekućinska kromatografija, masena spektrometrija i imunokemijske metode kao što su Western blot, ELISA test, imunoturbidimetrija i imunonefelometrija. U dodatku priručnika opisani su najvažniji proteini i enzimi plazme, njihova podjela, uloga i dijagnostičko značenje, oksidacijski stres s izvorima slobodnih radikala i značajem endogenih i egzogenih antioksidansa, kao i osnovne metaboličke funkcije glavnoga metaboličkog organa, jetre