Search

Background: Bisphenol A (BPA) exposure has been associated with increased incidence of diabetes and obesity in adults. Objectives: To evaluate whether an association between BPA urinary levels and insulin resistance as well as adiponectin and resistin production and serum concentrations may occur in obese children. Methods: Clinical and biochemical features of 141 obese children were collected. Serum resistin and adiponectin were evaluated. Insulin resistance and urinary BPA levels were assessed. Moreover, the effect of BPA on adiponectin and resistin gene expression in adipocytes from eight normal weight prepubertal children was investigated by quantitative real-time RT-PCR (qPCR). Results: Direct association between BPA and homeostasis model assessment (r = 0.23; p: 0.0069) and a strong inverse association between BPA and adiponectin have been found (r = −0.48; p < 0.0001). In adipocytes, resistin expression was detected only after BPA treatment, while adiponectin expression resulted down-regulated after BPA exposure (p < 0.05 at both 10 and 100 nM BPA concentrations). Conclusions: We suggest the involvement of BPA in the development of insulin resistance in childhood obesity highlighting that urinary BPA levels are directly associated with insulin resistance regardless of BMI. This association may be explained, at least partly, by the findings that BPA affects resistin and adiponectin production in adipose tissue cultures.

A thionine-modified carbon paste electrode for catechol and Bisphenol A (BPA) detection is presented. Graphite powder was modified by adsorbing thionine as electrochemical mediator. The electrochemical response of the modified carbon paste electrode (CPE) was determined before electrode modification with tyrosinase. Then, tyrosinase was added in order to assemble a biosensor. Once established the best operative conditions, an interelectrode reproducibility around 7% was obtained and the resulting biosensor showed improved sensitivities and (S = 139.6±1.1 nA/*M for catechol and S = 85.4±1.5 nA/*M for BPA) in comparison with the biosensor constructed without thionine (S = 104.4±0.5 nA/*M for catechol and S = 51.1±0.6 nA/*Mfor BPA) and low detection limits (0.15*Mfor both the electrodes and analytes). Also the comparison with the results reported in the literature showed higher sensitivity and lower detection limit for our biosensor. Moreover the functioning of the thionine-tyrosinase CPE was validated following a biodegradation process of water polluted by BPA and comparing the time changes of BPA concentration inferred by the biosensor calibration curve and those determined by means of HPLC measurements

Laccase from Rhus vernicifera was immobilized on a polypropylene membrane chemically modified with chromic acid. Ethylenediamine and glutaraldehyde were used as spacer and bifunctional coupling agent, respectively. Phenol was used as substrate. To know how the immobilization procedures affected the enzyme reaction rate the catalytic behavior of soluble and insoluble laccase was studied under isothermal conditions as a function of pH, temperature and substrate concentration. From these studies, two main singularities emerged: (i) the narrower pH–activity profile of the soluble enzyme in comparison to that of the insoluble counterpart and (ii) the increase in pH and thermal stability of the insoluble enzyme. The laccase catalytic behaviorwas also studied in a non-isothermal bioreactor as a function of substrate concentration and size of the applied transmembrane temperature difference. It was found that, under non-isothermal conditions and keeping constant the average temperature of the bioreactor, the enzyme reaction rate linearly increased with the increase of the temperature difference.

The bioremediation of waters polluted by Bisphenol A, taken as a model for endocrine disruptors, has been pursued by means of catalytic membranes in bioreactors operating under isothermal and non-isothermal conditions. Laccase from Trametes versicolor was immobilized on nylon membranes grafted with Glycidyl Methacrylate and using Phenylendiamine as spacer. The behaviour of the catalytic membrane was studied as a function of BPA concentration. Affinities of immobilized laccase towards BPA were found to increase with average temperature and under nonisothermal conditions. Percentage increases of enzyme activity, proportional to the applied temperature differences, were found to decrease with the increase of BPA concentrations. Interestingly, the highest levels of BPA biodegradation occurred at the lowest concentrations, in other words those present in wastewaters given the small water solubility of this compound. The results are discussed in terms of the process of thermodialysis by considering the additional BPA fluxes towards the immobilized enzymes driven by the temperature gradients.

The behaviour of three different laccase-based graphite biosensors was studied in view of their use in agricultural or industrial waters polluted by phenolic compounds. Catechol was used as a substrate model. Laccase from Trametes versicolor was immobilized on one biosensor (type A electrode) by adsorption while, on the other two biosensor types, laccase was covalently bound through the carboxylic groups created on the graphite by means of treatment with an electric potential difference (type B electrode) or with nitric acid (type C electrode). In the latter two cases, hexamethylenediamine and glutaraldehyde were used as the spacer and the coupling agent, respectively. The extension of linear response range and the sensitivity and time stability of each biosensor type were investigated. The type C biosensor gave the best results and its electrochemical properties proved comparable to those reported by other authors.

The effect of the immobilization time on the activity of immobilized â-galactosidase from K. lactis was investigated. Six biocatalytic membranes, different only for the time of the enzyme immobilization, were obtained by using nylon membranes grafted with glycidyl methacrylate (GMA) and activated by hexamethylenediamine (HMDA) and glutaraldehyde (Glu), used as spacer and coupling agent, respectively. Comparison between the isothermal and nonisothermal yield of these biocatalytic membranes was carried out in the process of lactose hydrolysis in milk. All of the results, reported as a function of the immobilization time, have evidenced the influence of our variable parameter on the activity of the catalytic membranes. The membrane giving highest yield under isothermal and nonisothermal conditions was that obtained with 2 h of immobilization time. The industrial application of these membranes has been discussed in terms of percentage reduction of the production times.

A modified polyethersulphone graft membrane was loaded with antiproteases, with the aim of reducing the active protease blood concentration during hemodialysis in acute catabolic renal failure or cardiopulmonary bypass. As protease/antiprotease system, elastase and α 1 -antitrypsin were used. The concentration of active elastase in aqueous solutions decreased as function of contact time with the membrane, approaching saturation. A 40% loss of elastase activity was obtained at pH 7.4, which was not due to autolysis, which accounted for 5% of the loss. The highest reduction was achieved at pH 9.0 (25% higher than at pH 7.4). The saturation level of elastase decrease, calculated by means of the Einstein equation, was reached after more than 47 minutes. We speculate that a time reduction might be achieved either increasing the concentration of immobilized antiproteases, or increasing the rate of elastase movement across the membranes by hydraulic, osmotic, or temperature gradients. This technology can be applied to hemodialysis, and in extracorporeal blood circulation to promote elastase release.

Bisphenol A and its analogues belong to the class of endocrine disrupting chemicals, massively employed by industries to produce polycarbonate and epoxy resins, designed to be in direct contact with foodstuffs. Their leaching from the canned packaging into its content results in food contamination. This review aims at offering a country-specific overview of the occurrence of bisphenols in six main categories of foodstuff marketed in the EU, based on monitoring studies performed in the 27 EU countries for which data are available and prevalently published in the last five years. The general overview of the literature data shows that concentration values of BPs detected into foodstuff is lower in Northern Europe than Southern Europe. A probable daily intake was hypothesized for some countries to provide an EU population exposure assessment. The consumption of canned meat and vegetables is responsible of PDI values higher than those of other food categories. These data emphasize that food and beverage monitoring should deserve greater attention especially by European countries for which no studies are available and especially with regards to bisphenols other than BPA whose limits are not set by the European regulations and whose toxicity has not been fully established.

Purpose Combined treatment based on cisplatin-loaded Poly(D,L-lactic-co-glicolic)acid (PLGA) nanoparticles (NP-C) plus the NSAID piroxicam was used as novel treatment for mesothelioma to reduce side effects related to cisplatin toxicity. Methods PLGA nanoparticles were prepared by double emulsion solvent evaporation method. Particle size, drug release profile and in vitro cellular uptake were characterized by TEM, DLS, LC/MS and fluorescence microscopy. MSTO-211H cell line was used to analyse NP-C biological efficacy by FACS and protein analysis. Results Cisplatin was encapsulated in 197 nm PLGA nanoparticles with 8.2% drug loading efficiency and 47% encapsulation efficiency. Cisplatin delivery from nanoparticles reaches 80% of total encapsulated drug in 14 days following a triphasic trend. PLGA nanoparticles in MSTO-211H cells were localized in the perinuclear space NP-C in combination with piroxicam induced apoptosis using a final cisplatin concentration 1.75 fold less than free drug. Delivered cisplatin cooperated with piroxicam in modulating cell cycle regulators as caspase-3, p53 and p21. Conclusions Cisplatin loaded PLGA nanoparticles plus piroxicam showed a good efficacy in exerting cytotoxic activity and inducing the same molecular apoptotic effects of the free drugs. Sustained cisplatin release allowed to use less amount of drug, decreasing toxic side effects. This novel approach could represent a new strategy for mesothelioma treatment. © 2014 Springer Science+Business Media New York.

A method based on solid-phase extraction followed by liquid chromatography, coupled to UV-visible and fluorescence spectrophotometry, has been developed for determination of bisphenol A (BPA) in canned tomatoes. The limit of quantification (LOQ) of the procedure used is 0.03 μM (0.26 μg BPA/kg tomato). For each of three different tomato based products (peeled, cherry and concentrated paste), 16 samples belonging to six commercial brands, retailed in Italian markets, were tested for migration of BPA epoxy-coating cans. All the tomato samples exhibited migration levels below 0.4 μg/kg, while samples subjected to heating process and/or can's damage by denting, exhibited a significant increase in the migration levels. In any case, no sample contained BPA exceeding the European Union limit for migration, set at 600 μg/kg of food. By comparing the results for each brand, no relevant difference in BPA concentration was found depending on the kind of tomato products. © 2014 Elsevier Ltd. All rights reserved.

The relevance of Bisphenol A (BPA) in human health is well-known. For this reason we designed and developed a biosensor based on a bionanocomposite (laccase–thionine–carbon black)-modified screen-printed electrode. Thionine, a commercially available dye, was used as electrochemical mediator coupled with a nanostructured carbon black. By means of cyclic voltammetry, the interaction of thionine adsorbed on modified screen printed electrode with laccase/BPA reaction products has been studied. In addition, the immobilization of laccase by physical adsorption on the surface of thionine–carbon black modified screen printed electrodes was investigated. The response of the biosensor has been optimized in terms of enzyme loading, pH and applied potential reaching a linear concentration range of 0.5–50 μM, a sensitivity of 5.0 ± 0.1 nA/μM and a limit-of-detection (LOD) of 0.2 μM. The developed biosensor has been also challenged in tomato juice samples contained in metallic cans where release of BPA due to the epoxy resin coating can be assumed. A satisfactory recovery value comprised between 92% and 120% was obtained.

Glucose oxidase (GOD) immobilized into sol–gel matrices was studied by using Micro-Attenuated Total Reflection Fourier Transform Infrared (micro-ATR FT-IR) spectroscopy in order to characterize enzyme distribution and secondary structure in systems with valuable potentialities in amperometric and optical biosensing. Spectra were acquired in the 4000–600 cm− 1 frequency region and the analysis of specific fingerprints in the FT-IR spectra evidenced that the enzyme was actually immobilized in the matrix. The enzyme spatial distribution was obtained by examining the amide I and amide II band region of spectra from defined sample positions. The deconvolution of the amide I band in terms of lorentzian functions provided information on the secondary structure of the immobilized GOD. By this approach a macroscopic preservation of GOD activity upon immobilization was evidenced along with the existence of some matrix sites with locally inactivated GOD. To our knowledge this is the first example of point-by-point characterization of conformational changes of immobilized enzyme by means of micro-ATR infrared spectroscopy, thus confirming that this technique can be usefully employed for a non- or minimally-invasive detailed micro-characterization of catalytic supports in order to improve their functionality.

A fluidized bed reactor, filled with laccase-based beads, has been employed to bioremediate aqueous solutions polluted by endocrine disruptors belonging to the alkylphenols (APs) class. In particular Octylphenol and Nonylphenol have been studied. The catalytic activity of free and immobilized laccase from Trametes versicolor has been characterized as a function of pH, temperature and substrate concentration in the reaction medium. In view of practical applications for each substrate concentration the removal efficiency (RE), the time to halve the initial concentration (tau(50)), and the t(c-0), i.e. the time to reach complete pollutant removal, have been calculated. The immobilized laccase exhibited a lower affinity for octylphenol (K-m = 1.11 mM) than for Nonylphenol (K-m = 0.72 mM), but all the other parameters of applicative interest resulted more significant for octylphenol. For example, the times to reach the complete removal of octylphenol compared to those for nonylphenol at the same concentration is shorter of about 15% (at low concentrations) up to 40% (at high concentrations). The study of cell proliferation with MPP89 cells, a human mesothelioma cell line, and the assay with the YES test indicated the loss of estrogenic activity of the APs solutions after laccase treatment. (C) 2013 Elsevier B.V. All rights reserved.

Pregnant adult Balb-C mice were exposed daily to two different doses of Bisphenol A (BPA) by subcutaneous injection beginning on gestational day 1 through the seventh day after delivery. The mothers were sacrificed on postpartum day 21, and the offspring were sacrificed at 3 months of age. Control mice were subjected to the same experimental protocol but received saline injections. The liver, muscles, hindbrain and forebrain of the offspring were dissected and processed using HPLC to assess the level of BPA in the tissues and to determine its dependence on the exposure dose and gender. For comparison, the same tissues were dissected from the mothers and analysed. We report the following results: (1) the level of BPA that accumulated in a given tissue was dependent on the exposure dose; (2) the rank order of BPA accumulation in the various tissues was dependent on the gender of the offspring; (3) the average BPA concentrations in the liver and muscle of the female offspring were higher than in the males; and (4) the average BPA concentration in the central nervous system (i.e., the hindbrain and forebrain) of the male offspring was higher than in the females. (C) 2011 Elsevier B.V. All rights reserved.