Gül Özhan

Acrylamide-induced oxidative stress in human erythrocytes

Acrylamide (AA), a widely used industrial chemical, is shown to be neurotoxic, mutagenic and carcinogenic. This study was carried out to investigate the effects of different doses of AA on lipid peroxidation (LPO), haemolysis, methaemoglobin (MetHb) and antioxidant system in human erythrocytes in vitro. Erythrocyte solutions were incubated with 0.10, 0.25, 0.50 and 1.00 mM of AA at 37°C for 1 hour. At the end of the incubation, malondialdehyde (MDA), an end product of LPO, was determined by liquid chromatography (LC) while total glutathione, reduced glutathione (GSH) levels, activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) enzymes and the rates of haemolysis and MetHb were determined by spectrophotometric methods. All of the studied concentrations of AA increased MetHb formation and SOD activity, and induced MDA formation and haemolysis due to the destruction of erythrocyte cell membrane. AA caused a decrease in the activities of GSH-Px, CAT and GSH levels. However, these effects of AA were seen only at higher concentrations than AA intake estimated for populations in many countries. We suggest that LPO process may not be involved in the toxic effects of AA in low concentrations, although the present results showed that the studied concentrations of AA exert deteriorating effects on antioxidant enzyme activities, LPO process and haemolysis.

Determination of Commonly Used Herbicides in Surface Water Using Solid-Phase Extraction and Dual-Column HPLC-DAD

The present study describes the application of different solid-phase extraction techniques for the extraction, separation, and quantitative determination of 10 commonly used herbicides with different chemical structures (chlorsulfuron, diuron, bentazone, linuron, chlorpropham, fenoxoprop-ethyl, MCPA, diclofop-methyl, fluazifop-butyl, trifluraline) in water. Octadecyl (C18) Empore extraction disks, octadecyl (C18), and stryene divinylbenzene (SDB) Bond Elut Env cartridges were compared for solid-phase extraction efficiency. Herbicides were separated and quantified by reversed-phase high performance liquid chromatography with diode-array detection (HPLC-DAD) with simultaneous separation on two columns of differing polarity (C18 and CN) to confirm identification. Analytical separation was performed simultaneously on C18 and CN columns. Reanalysis of the sample extracts on a (cyano) CN column were used to confirm the identity of these compounds. Method optimization and validation parameters were presented in this work. Recoveries varied from 76.0% to 99.0% for C18 disks, from 75.1% to 100.0% for C18 cartridges, and from 54.0% to 98.0% for SDB cartridges over concentrations at 0.025–0.4 μg L−1. The limits of detection were 0.012–0.035 μg L−1.

In Vitro Toxicological Assessment of Magnesium Oxide Nanoparticle Exposure in Several Mammalian Cell Types

Worldwide researchers have rising concerns about magnesium-based materials, especially magnesium oxide (MgO) nanaoparticles, due to increasing usage as promising structural materials in various fields including cancer treatment. However, there is a serious lack of information about their toxicity at the cellular and molecular levels. In this study, the toxic potentials of MgO nanoparticles were investigated on liver (HepG2), kidney (NRK-52E), intestine (Caco-2), and lung (A549) cell lines. For the toxicological assessment, the following assays were used: the particle characterization by transmission electron microscopy, the determination of cellular uptake by inductively coupled plasma-mass spectrometry, MTT and neutral red uptake assays for cytotoxicity, comet assay for genotoxicity, and the determination of malondialdehyde (MDA), 8-hydroxydeoxyguanosine, protein carbonyl, and glutathione levels by enzyme-linked immune sorbent assays for the potential of oxidative damage and annexin V-fluorescein isothiocyanate (FITC) apoptosis detection assay with propidium iodide (PI) for apoptosis. Magnesium oxide nanoparticles were taken up by the cells depending on their concentration and agglomeration/aggregation potentials. Magnesium oxide nanoparticles induced DNA (≤14.27 fold) and oxidative damage. At a concentration of ≥323.39 µg/mL, MgO nanoparticles caused 50% inhibition in cell viability by 2 different cytotoxicity assays. The cell sensitivity to cytotoxic and genotoxic damage induced by MgO nanoparticles was ranked as HepG2 < A549 < Caco-2 < NRK-52E. Although it was observed that MgO nanoparticles induced apoptotic effects on the cells, apoptosis was not the main cell death. DNA damage, cell death, and oxidative damage effects of MgO nanoparticles should raise concern about the safety associated with their applications in consumer products.

Liquid chromatographic analysis of maneb and its main degradation product, ethylenethiouera, in fruit juice

Ethylenethiourea (ETU), a possible human carcinogen and an antithyroid compound, is the main degradation product of the fungicide, maneb, which is widely used in agriculture. In this study, a rapid and accurate method for the determination of maneb and ETU in various fruit juices (tomato, grape and apple) was developed requiring minimal clean-up of sample extract, no derivatization prior to injection and no specialized LC detectors. Samples were cleaned up using silica and octadecylsilica (C18) cartridges before injection into liquid chromatography (LC) with diode-array detection (DAD). Recoveries ranged between 90 and 101% with relative standard deviations from 0.7 to 3.8%. The limits of determination of maneb and ETU were 0.1 and 0.01 mg l−1, respectively. The proposed method was used to monitor the presence of maneb and ETU in commercial samples taken from different markets of Istanbul, Turkey. Maneb was found in one tomato juice sample at a concentration of 0.45 mg l−1 but ETU was below the LOQ. Two tomato juices had no detectable maneb residue but contained ETU at levels of 0.08 and 0.11 mg l−1.

Zinc oxide nanoparticles induced cyto- and genotoxicity in kidney epithelial cells

Abstract The wide uses of zinc oxide nanoparticles (nano-ZnO) in industrial, cosmetics, medicine, food production and electronics associate with increase in occupational and public exposure. Although, toxicity of nano-ZnO has been extensively studied on many different cell types and animal systems, there is a significant lack of toxicological data focus on nephrotoxic potential of nano-ZnO. In this study, the cyto- and genotoxic effects of nano-ZnO on rat kidney epithelial cells (NRK-52E) were investigated by using different assays. Nano-ZnO (10–50 nm of sizes) were synthesized by sol–gel method. For the cytotoxic effect of nano-ZnO, mean of inhibition concentration (IC50) values in cell line was evaluated by MTT, Trypan Blue (TB) and Neutral Red Uptake (NRU) assays at 25.0–100.0 μg/mL exposure concentrations. Nano-ZnO showed cytotoxic activity by acting on different targets in renal cells, with IC50 ≥ 73.05 μg/mL. Comet assay was used to evaluate the genotoxicity of nano-ZnO (12.5–50.0 μg/mL). Nano-ZnO caused statistically significant DNA damage. Our results highlight the important risk of cyto- and genotoxic effects of nano-ZnO over the kidney.

Polymorphisms in tumour necrosis factor alpha (TNFα) gene in patients with acute pancreatitis.

Proinflammatory cytokines, such as tumour necrosis factor α (TNFα), play fundamental roles in the pathogenesis of acute pancreatitis (AP). The aim of this study was to determine if polymorphisms in the TNFα gene are associated with AP. Two polymorphisms located in the promoter region (positions −308 and −238) in TNFα gene were determined using polymerase chain reaction- (PCR-) restriction fragment length polymorphism (RFLP) methods in 103 patients with AP and 92 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using logistic regression analysis adjusted for age, sex, BMI and smoking. The frequencies of TNFα polymorphisms were both similar in patients with mild or severe pancreatitis, so were in pancreatitis patients and in controls. We suggest that both SNPs of TNFα are not genetic risk factor for AP susceptibility (OR = 1.63; 95% CI: 1.13−4.01 for TNFα −308 and OR = 0.86; 95% CI: 0.75−1.77 for TNFα −238).

A simple method for the determination of carbaryl and 1-naphthol in fruit juices by high-performance liquid chromatography-diode-array detection

Carbaryl (Sevin) is a widely used N-methylcarbamate insecticide. In this study, a simple and sensitive reversed-phase, high-performance liquid chromatography method with diode-array detection has been developed for the determination of low levels of carbaryl and its degradation products 1-naphthol in several kinds of canned pure fruit juice. The compounds were captured on a C18 cartridge. The analytes were separated on a C18 column using a linear gradient of 40 to 60% acetonitrile in water in a period of 20 min. The extraction recoveries of carbaryl and 1-naphthol were in the range 93.5 to 98.0% and 90.7 to 96.0% for fruit juice, respectively. The detection limit was below 0.8 ng/ml and the calibration curves showed good linearity between 0.9998 and 0.9999.

Determination of cyclonite (RDX) in human plasma by high- performance liquid chromatography

A simple and sensitive HPLC method has been developed for the assay of cyclonite (RDX) in human plasma. The assay involves solid-phase extraction on Tox-clean RC SPE cartridges and isocratic reversed-phase chromatography with diode-array detection. The assay was linear over the concentration range of 0.01-2.0 microg/ml for plasma with a lower limit of detection of 0.005 microg/ml. Both the within-day and day-to-day reproducibilities and accuracies were less than 10.15 and 1.9%, respectively. The method was applied to evaluate RDX concentration in plasma samples obtained from soldiers exposed RDX.

Colloidal nanocarriers for the enhanced cutaneous delivery of naftifine: characterization studies and in vitro and in vivo evaluations

In topical administration of antifungals, the drugs should pass the stratum corneum to reach lower layers of the skin in effective concentrations. Thus, the formulation of antifungal agents into a suitable delivery system is important for the topical treatment of fungal infections. Nanosized colloidal carriers have gained great interest during the recent years to serve as efficient promoters of drug penetration into the skin. Microemulsions are soft colloidal nanosized drug carriers, which are thermodynamically stable and isotropic systems. They have been extensively explored for the enhancement of skin delivery of drugs. This study was carried out to exploit the feasibility of colloidal carriers as to improve skin transport of naftifine, which is an allylamine antifungal drug. The microemulsions were formulated by construction of pseudoternary phase diagrams and composed of oleic acid (oil phase), Kolliphor® EL or Kolliphor® RH40 (surfactant), Transcutol® (cosurfactant), and water (aqueous phase). The plain and drug-loaded microemulsions were characterized in terms of isotropy, particle size and size distribution, pH value, refractive index, viscosity, and conductivity. The in vitro skin uptake of naftifine from microemulsions was studied using tape stripping technique in pig skin. The drug penetrated significantly into stratum corneum from microemulsions compared to its marketed cream (P<0.05). Moreover, the microemulsion formulations led to highly significant amount of naftifine deposition in deeper layers of skin than that of commercial formulation (P<0.001). Microemulsion–skin interaction was confirmed by attenuated total reflectance – Fourier transformed infrared spectroscopy data, in vitro. The results of the in vivo tape stripping experiment showed similar trends as the in vitro skin penetration study. Topical application of the microemulsion on human forearms in vivo enhanced significantly the distribution and the amount of naftifine penetrated into the stratum corneum as compared to the marketed formulation (P<0.05). The relative safety of the microemulsion formulations was demonstrated with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability test. This study indicated that the nanosized colloidal carriers developed could be considered as an effective and safe topical delivery system for naftifine.

Genotoxic activities of drug-nitrite interaction products

Abstract At first 28 orally administered drugs, considered to be potentially nitrosatable on the basis of their chemical structure, have been nitrosated with nitrite under simulated stomach conditions. A maximum daily dose of each drug was incubated with a nitrite concentration that can be found after a normal meal in the stomach at 37°C over 1 h. Reaction was started at pH 6.8–7.0 and stopped at pH 2.0, so we had the same pH change that occurs in the stomach. Secondly the genotoxic activities of drug-nitrite interaction products were tested by the umu-test with Salmonella typhimurium TA 1535/pSK1002 as tester strain in the presence and absence of metabolic activation. By the umu-test, among the nitrosation products of drugs examined 22 products showed genotoxicity at different levels. Other six products showed negative results by the umu-test.