Zonguldak Karaelmas University

About: Zonguldak Karaelmas University is a based out in . It is known for research contribution in the topics: Population & Copolymer. The organization has 1939 authors who have published 4296 publications receiving 62466 citations.

Oxidative stress in acne vulgaris.

Abstract: Background Acne vulgaris is one of the common dermatological diseases and its pathogenesis is multifactorial. In this study, we aimed to determine the effects of oxidative stress in acne vulgaris. Materials and methods The study involved 32 patients with acne vulgaris in the patient group and 34 healthy adults in the control group. The parameters of oxidative stress such as catalase (CAT), superoxide dismutase (SOD), xanthine oxidase (XO), nitric oxide (NO) and malondialdehyde (MDA) in the venous blood of patients were measured spectrophotometrically. The values were compared with those of the control group. Results The serum levels of MDA and XO activity in the patients with acne vulgaris were significantly higher than those of the controls. A significantly lower SOD and CAT activity was found in the patient group than in the control group. Although the patient group had higher serum levels of NO than the control group, the difference was not statistically significant. Conclusion These results suggest that oxidative damage may play a role in the pathogenesis of acne; therefore, significant alterations may occur in the antioxidant defence system.

Vitamin E Protects Against Oxidative Damage Caused by Formaldehyde in the Liver and Plasma of Rats

Abstract: It is well known that formaldehyde (FA) and reactive oxygen species (ROS) are cytotoxic and potentially carcinogenic. Although the individual effects of these reactants on cells have been investigated, the cytotoxicity exerted by the coexistence of FA and ROS is poorly understood. The present study was carried out to evaluate oxidant/antioxidant status and biochemical changes occurring after chronic formaldehyde toxicity in liver tissue and plasma of rats and protective effect of vitamin E (vit E) against oxidative damage. Eighteen rats were divided into three groups: (1) control rats, (2) rats treated with FA (FAt), and (3) rats treated with FA plus vit E (FAt + vit E) groups. After the treatment, the animals were sacrificed and liver tissues were removed for biochemical investigations. As a result, FA treatment significantly increased the levels of tissue malondialdehyde (MDA), protein carbonyl (PC), nitric oxide (NO) and the activity of xanthine oxidase enzyme (XO). On the other hand, FA exposure led to decrease in superoxide dismutase (SOD) and catalase (CAT) activities in liver tissues compared to control. FA caused significant decreases in total protein (TP) and albumin (ALB) whereas increases in aspartate transaminase (AST), alanine aminotransferase (AST), alkaline phosphatase (ALP) and interleukine-2 (IL-2) levels in plasma. Vit E treatment abolished these changes at a level similar to the control group. It was concluded that vit E treatment might be beneficial in preventing FA-induced liver tissue damage, and therefore have potential for clinical use.

Assessment of BeiDou differential code bias variations from multi-GNSS network observations

Abstract: . The differential code bias (DCB) of global navigation satellite systems (GNSSs) affects precise ionospheric modeling and applications. In this paper, daily DCBs of the BeiDou Navigation Satellite System (BDS) are estimated and investigated from 2-year multi-GNSS network observations (2013–2014) based on global ionospheric maps (GIMs) from the Center for Orbit Determination in Europe (CODE), which are compared with Global Positioning System (GPS) results. The DCB of BDS satellites is a little less stable than GPS solutions, especially for geostationary Earth orbit (GEO) satellites. The BDS GEO observations decrease the precision of inclined geosynchronous satellite orbit (IGSO) and medium Earth orbit (MEO) DCB estimations. The RMS of BDS satellites DCB decreases to about 0.2 ns when we remove BDS GEO observations. Zero-mean condition effects are not the dominant factor for the higher RMS of BDS satellites DCB. Although there are no obvious secular variations in the DCB time series, sub-nanosecond variations are visible for both BDS and GPS satellites DCBs during 2013–2014. For satellites in the same orbital plane, their DCB variations have similar characteristics. In addition, variations in receivers DCB in the same region are found with a similar pattern between BDS and GPS. These variations in both GPS and BDS DCBs are mainly related to the estimated error from ionospheric variability, while the BDS DCB intrinsic variation is in sub-nanoseconds.

Contribution of flavonoid antioxidants to the preventive effect of mesna in cyclophosphamide-induced cystitis in rats

Abstract: Cyclophosphamide (CP) is widely used, alone or in combination with other chemotherapeutic agents, for treatment of neoplastic diseases. Its urotoxicity may cause dose-limiting side-effects, for example hemorrhagic cystitis. The agent most often used to prevent this side-effect is mesna (2-mercaptoethane sulfonate). Overproduction of reactive oxygen species during inflammation is one reason for possible urothelial injury. The aim of this study was to evaluate whether combinations of quercetin and epigallocatechin 3-gallate (EGCG), flavonoid antioxidants and mesna could prevent cystitis induced by cyclophosphamide, better than mesna alone. A total of 38 male Sprague–Dawley rats were divided into five groups. Four groups received single dose of CP (100 mg kg−1) intraperitoneally at the same time. Group 2 received CP only, group 3 received mesna (3×21.5 mg kg−1), group 4 received a single dose of mesna+EGCG (2×20 mg kg−1), and group 5 received a single dose of mesna+quercetin (2×20 mg kg−1), before and after CP injection. Group 1 (not treated) served as control. CP injection alone resulted in severe cystitis. Mesna resulted in some, but not full, protection against CP toxicity. Quercetin and catechine, together with mesna, resulted in full protection against CP toxicity, on the basis of histopathology of the urinary bladder. It was concluded that oxidants might be important in the pathogenesis of CP-induced cystitis, and that flavonoid antioxidants, used in addition to mesna, may help to ameliorate bladder damage.