Geyikoglu, Fatime; Emir, Murat; Colak, Suat; Koc, Kubra; Turkez, Hasan; Bakir, Murat; Hosseinigouzdagani, Mirkhalil; Cerig, Salim; Keles, Osman Nuri; Ozek, Nihal Simsek

Cisplatin-based chemotherapy is responsible for a large number of renal failures, and it is still associated with high rates of mortality today. Oleuropein (OLE) presents a plethora of pharmacological beneficial properties. In this study we investigated whether OLE could provide sufficient protection against cisplatin-induced nephrotoxicity. With this aim, Sprague-Dawley rats were divided into eight groups: control; 7 mg/kg/d cisplatin, 50 mg/kg, 100 mg/kg, and 200 mg/kg OLE; and treatment with OLE for 3 days starting at 24 hours following cisplatin injection. After exposure to the chemotherapy agent and OLE, oxidative DNA damage was quantitated in the renal tissue of experimental animals by measuring the amount of 8-hydroxy-2′-deoxyguanosine (8-OHdG) adducts. Malondialdehyde (MDA) level, total oxidative stress (TOS), and total antioxidant status (TAS) were assessed to determine the oxidative injury in kidney cells. The histology of the kidney was examined using four different staining methods: hematoxylin-eosin (H&E), periodic acid Schiff (PAS), Masson trichrome, and amyloid. In addition, the blood urea nitrogen (BUN), uric acid (UA), and creatinine (CRE) levels were established. Our experimental data showed that tissue 8-OHdG levels were significantly higher in the cisplatin group when compared to the control group. The glomerular cells were sensitive to cisplatin as tubular cells. In addition, treatment with cisplatin elevated the levels of BUN, UA, CRE, and TOS, but lowered the level of TAS compared to the control group. The OLE therapy modulated oxidative stress in order to restore normal kidney function and reduced the formation of 8-OHdG induced by cisplatin. Furthermore, the OLE treatment significantly reduced pathological findings in renal tissue. We demonstrate for the first time that OLE presents significant cytoprotective properties against cisplatin-induced genotoxicity by restoring the antioxidant system of the renal tissue. According to our findings, OLE is a promising novel natural source for the prevention of serious kidney damage in current chemotherapies.

Birinci, Aysenur; Eren, Hilal; Coldur, Fatih; Coskun, Emine; Andac, Muberra

A new solid contact copper selective electrode with a poly (vinyl chloride) (PVC) membrane consisting of o-xylylenebis(N,N-diisobutyldithiocarbamate) as ionophore has been prepared. The main novelties of constructed ion selective electrode concept are the enhanced robustness, cheapness, and fastness due to the use of solid contacts. The electrode exhibits a rapid (< 10 seconds) and near-Nernstian response to Cu2+ activity from 10−1 to 10−6 mol/L at the pH range of 4.0–6.0. No serious interference from common ions was found. The electrode characterizes by high potential stability, reproducibility, and full repeatability. The electrode was used as an indicator electrode in potentiometric titration of Cu(II) ions with EDTA and for the direct assay of tea infusion samples by means of the calibration graph technique. The results compared favorably with those obtained by the atomic absorption spectroscopy (AAS).

Andac, Muberra; Eren, Hilal; Coldur, Fatih

A rapid, simple and inexpensive flow injection potentiometric method for the determination of nitrate in leafy vegetables is described. Six commonly consumed fresh leafy vegetables (mint, lettuce, savoy cabbage, stinging nettle, parsley and cress) were obtained from bazaar in Samsun. An all-solid-state miniaturized nitrate-selective electrode was used as a detector in a low-dead-volume flow through cell. Nitrate was determined in the linear range from 0.1 to 100 mmol/L with detection limit of 0.066 mmol/L. The calibration slope is 52.96 ± 1.02 mV/decade in the linear range. The relative standard deviation (RSD) of the electrode response of 100, 10 and 1 mmol/L NO 3 - was 0.46, 0.49 and 0.98%, respectively. The flow injection analysis (FIA) throughput was 90 samples/h. The FIA results were compared with those obtained by spectrophotometric method. The results of the study show that nitrate contents in fresh leafy vegetables ranged from 97 to 1861 mg/kg.