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    Determination of melamine in milk and dairy products by high performance liquid chromatography
    (Elsevier Science Inc, 2012) Filazi, A.; Sireli, U. T.; Ekici, H.; Can, H. Y.; Karagoz, A.
    phase HPLC method was developed for the determination of melamine in milk (pasteurized and UHT milk) and dairy products (powdered infant formula, fruit yogurt, soft cheese, and milk powder). Following extraction with acetonitrile: water (50: 50, vol/vol), samples were purified by filter (0.45 mu m), separated on a Nucleosil C8 column (4.6 mm x 250 mm, 3 mu m) with acetonitrile: 10 mmol/L sodium l-octane sulfonate (pH 3.1; 15: 85, vol/vol) as mobile phase at a flow rate of 1 mL/min, and determined by a photodiode array detector. A linear calibration curve was obtained in the concentration range from 0.05 to 5 mg/kg. Milk and dairy products were fortified with melamine at 4 levels producing average recovery yields of 95 to 109%. The limits of detection and quantification of melamine were 35 to 110 and 105 to 340 mu g/kg, respectively. The method was then used to analyze 300 samples of milk and dairy products purchased from major retailers in Turkey. Melamine was not found in infant formulas and pasteurized UHT milk, whereas 2% of cheese, 8% of milk powder, and 44% of yogurt samples contained melamine at the 121, 694 + 146, and 294 + 98 mu g/kg levels, respectively. These findings were below the limits set by the Codex Alimentarius Commission and European Union legislation. This is the first study to confirm the existence of melamine in milk and dairy products in Turkey. Consumption of foods containing these low levels of melamine does not constitute a health risk for consumers.
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    Late effects of cutaneous 3-methylcholanthrene exposure on DNA damage-related pleiotropic growth factors and oxidative stress markers in mice
    (Comenius Univ, 2020) Devrim, T.; Ekici, H.; Devrim, A. K.; Sozmen, M.; Senol, A.; Bozkurt, K. M.; Yalcin, S.
    BACKGROUND: Skin is the body's first defence against direct exposure to variety of chemicals. Polycyclic aromatic hydrocarbons such as 3-methylcholanthrene (3-MC) are common in polluted urban air and have a potential of producing harmful effects. Moreover, their late effects can occur months or years after exposure. OBJECTIVES: We aimed to investigate the long-term effects of 3-MC induced dermal toxicity on the expression of markers of apoptosis, pleiotropic cytokines, and oxidative stress and to determine the protective effect of cisplatin. METHODS: Groups were designed as control (group 1), 3-MC applied (group 2) and 3-MC+cisplatin applied mice (group 3). Cutaneous expressions of TGF beta, PDGFA, PDGFC, bFGF, PDGFR alpha, USP28, and Ki67 were evaluated with qPCR. Total oxidant (TOS), total antioxidant (TAS) and oxidative stress index (OSI) values were determined in liver and kidney tissues. RESULTS: The expression levels of TGF beta, PDGFR alpha, USP-28, Ki67, and PDGFA were decreased significantly in MC applied groups. Renal TAS levels were significantly lower in group-3. Liver and kidney OSI values were increased in both groups 2 and 3. CONCLUSION: The results indicated that low dose 3-MC caused oxidative stress and downregulated apoptotic and cytokine markers in the long term and cisplatin had no ameliorative effects on this degeneration processes (Tab. 3, Fig. 3, Ref. 32).
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    Novel amoxicillin nanoparticles formulated as sustained release delivery system for poultry use
    (Wiley, 2018) Guncum, E.; Bakirel, T.; Anlas, C.; Ekici, H.; Isiklan, N.
    Amoxicillin is used in the treatment and prevention of a wide range of diseases in poultry breeding. However, its short half-life and low bioavailability restrict its clinical application in these species. Entrapment of drugs into polymeric nanoparticles (nps) presents a means to improve gastrointestinal absorption and oral bioavailability of drugs. This study was aimed to overcome limitation of amoxicillin use in poultry breeding. Amoxicillin was loaded into sodium alginate-polyvinyl alcohol (NaAlg-PVA) blend nps, and characterization of the prepared nps was performed. For pharmacokinetic study, commercial male broilers were used and comparative pharmacokinetics of free and nanoparticle form of amoxicillin were investigated. Twenty-one broilers were divided into three groups. All groups received 10mg/kg drug. Blood samples were collected, and drug plasma concentrations were determined by HPLC. The results demonstrated that the particle size, zeta potential, encapsulation efficiency, and loading capacity of the nps were 513.96 +/- 19.46nm, -45.36 +/- 1.35mV, 43.66 +/- 3.30, and 12.06 +/- 0.83%, respectively. In vitro drug release exhibited a biphasic pattern with an initial burst release of 18% within 2hr followed by a sustained release over 22hr. The pharmacokinetic results showed that amoxicillin nps have higher bioavailability and longer plasma half-life (p<.01) than free amoxicillin. These results indicate that amoxicillin nano formulation is suitable for oral administration in broilers.