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Öğe Analysis of tumor necrosis factor alpha-induced and nuclear factor kappa B-silenced LNCaP prostate cancer cells by RT-qPCR(Spandidos Publ Ltd, 2014) Gonen-Korkmaz, Ceren; Sevin, Gulnur; Gokce, Goksel; Arun, Mehmet Zuhuri; Yildirim, Gokce; Reel, Buket; Kaymak, Aysegul; Ogut, DenizProstate cancer is the second leading cause of morbidity and mortality in males in the Western world. In the present study, LNCaP, which is an androgen receptor-positive and androgen-responsive prostate cancer cell line derived from lymph node metastasis, and DU 145, which is an androgen receptor-negative prostate cancer cell line derived from brain metastasis, were investigated. TNF alpha treatment decreased p105 and p50 expression and R1881 treatment slightly decreased p105 expression but increased p50 expression with or without TNF alpha induction. As an aggressive prostate cancer cell line, DU145 transfected with six transmembrane protein of prostate (STAMP)1 or STAMP2 was also exposed to TNF alpha. Western blotting indicated that transfection with either STAMP gene caused a significant increase in NF kappa B expression following TNF alpha induction. In addition, following the treatment of LNCaP cells with TNF alpha, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was performed with a panel of apoptosis-related gene primers. The apoptosis-related genes p53, p73, caspase 7 and caspase 9 showed statistically significant increases in expression levels while the expression levels of MDM2 and STAMP1 decreased following TNF alpha induction. Furthermore, LNCaP cells were transfected with a small interfering NF kappa B (siNF kappa B) construct for 1 and 4 days and induced with TNF alpha for the final 24 h. RT-qPCR amplifications were performed with apoptosis-related gene primers, including p53, caspases and STAMPs. However, no changes in the level of STAMP2 were observed between cells in the presence or absence of TNF alpha induction or between those transfected or not transfected with siNF kappa B; however, the level of STAMP1 was significantly decreased by TNF alpha induction, and significantly increased with siNF kappa B transfection. Silencing of the survival gene NF kappa B caused anti-apoptotic STAMPI expression to increase, which repressed p53, together with MDM2. NF kappa B silencing had varying effects on a panel of cancer regulatory genes. Therefore, the effective inhibition of NF kappa B may be critical in providing a targeted pathway for prostate cancer prevention.Öğe Design and in vitro, in vivo evaluation of antioxidant bioadhesive gelsfor burn treatment(Tubitak Scientific & Technical Research Council Turkey, 2022) Gokce, Goksel; Karavana, Sinem Yaprak; Bagriyanik, Alper; Pekcetin, Cetin; Algin Yapar, Evren; Aybar Tural, Gulsen; Gokce, Evren HomanBurn wounds are frequently encountered health problems, which need a new treatment approach especially in terms of good patient compliance. Availability of use of antioxidant agents and bio-adhesive gels in tissue healing can be an alternative as a new approach for wound healing. Antioxidant taurine containing bio-adhesive gels were prepared by using carbopol (CP) 940 and 934. Rheological and texture analyses were carried out on bio-adhesive gels for in vitro characterization. Wound model on Wistar rats was used to evaluate the in vivo evaluation of gels. Rheological and texture analyses showed that a carbopol bioadhesive gel has acceptable topically use dosage characteristics and in combination with Taurine it presented a successful wound healing effect via antioxidant parameters. In conclusion, bio-adhesive CP 940 (2%) gel containing 50 mM taurine could be promising in the treatment of burns by oxidative stress.Öğe Different Responses of RT-PCR Amplifications after Tumor Necrosis alpha (TNFa) Induction at Nuclear Factor kappa B (NFkB) Gene Silenced LNCaP Cells(Federation Amer Soc Exp Biol, 2013) Gonen-Korkmaz, Ceren; Sevin, Gulnur; Gokce, Goksel; Arun, Mehmet Z.; Yetik-Anacak, Gunay; Yildirim, Gokce; Reel, Buket; Ogut, Deniz; Kaymak, AysegulÖğe Ergothioneine prevents endothelial dysfunction induced by mercury chloride(Spandidos Publ Ltd, 2018) Gokce, Goksel; Arun, Mehmet Zuhuri; Ertuna, ElifExposure to mercury has detrimental effects on the cardiovascular system, particularly the vascular endothelium. The present study aimed to investigate the effects of ergothioneine (EGT) on endothelial dysfunction induced by low-dose mercury chloride (HgCl2). Agonist-induced contractions and relaxations were evaluated in isolated aortic rings from 3-month-old male Wistar rats treated by intra-muscular injection to caudal hind leg muscle with HgCl2 (first dose, 4.6 mu g/kg; subsequent doses, 0.07 mu g/kg/day for 15 days) and optionally with EGT (2 mu g/kg for 30 days). Reactive oxygen species (ROS) in aortic rings were measured by means of lucigenin- and luminol-enhanced chemiluminescence. The protein level of endothelial nitric oxide synthase was evaluated by ELISA. Blood glutathione (GSH) and catalase levels, lipid peroxidation and total nitrite were measured spectrophotometrically. The results indicated that low-dose HgCl2 administration impaired acetylcholine (ACh)-induced relaxation and potentiated phenylephrine-and serotonin-induced contractions in rat aortas. In addition, HgCl2 significantly increased the levels of ROS in the aortic tissue. EGT prevented the loss of ACh-induced relaxations and the increase in contractile responses. These effects were accompanied by a significant decrease in ROS levels. EGT also improved the ratio of reduced GSH to oxidized GSH and catalase levels with a concomitant decrease in lipid peroxidation. In conclusion, to the best of our knowledge, the present study was the first to report that EGT prevents endothelial dysfunction induced by low-dose HgCl2 administration. EGT may serve as a therapeutic tool to reduce mercury-associated cardiovascular complications via improving the antioxidant status.Öğe Evaluation of antidiabetic, antioxidant and vasoprotective effects of Posidonia oceanica extract(Elsevier Ireland Ltd, 2008) Gokce, Goksel; Haznedaroglu, Mehmet ZekiThe aim of this study is to evaluate antidiabetic, antioxidant and vasoprotective effects of Posidonia oceanica extract (POE) in alloxan diabetic rats. Posidonia oceanica (L) Delile (Posidoniaceae), is a widely allocated phanerogam in Mediterranean and Aegean Sea. Up to date, no published data relevant to use of the plant in traditional medicine are available. However, decoction of the leaves has been quoted to be used as a remedy for diabetes mellitus and hypertension by villagers living by the sea coast of Western Anatolia. Oral administration of extract for 15 days (50, 150, and 250 mg/kg b.wt.) resulted in a dose-dependent decrease in blood glucose. Relaxant responses to acetylcholine (ACh) in diabetic thoracic aorta were restored by POE treatment (50, 150, and 250mg/kg b.wt.). POE also attenuated the augmented phenylephrine (PE) and serotonin (5-HT) contractions. At concentration levels of 150 and 250 mg/kg b.wt., POE exerted a protective effect on the significantly decreased levels of antioxidants namely, glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase and nitric oxide (NO). POE (50 mg/kg b.wt.) produced no effect on alloxan-induced alterations in the antioxidant status while possessing glucose lowering and vasoprotective activities. Furthermore, liver and kidney function markers, leucocyte counts, body weight and liver glycogen content remained unchanged at dose level of 50 mg/kg b.wt., when compared with diabetic control group. These results suggest that antidiabetic and vasoprotective effects of POE may be unrelated to its antioxidant properties. (c) 2007 Elsevier Ireland Ltd. All rights reserved.Öğe Evaluation of characteristics and in vitro antioxidant properties of RSV loaded hyaluronic acid-DPPC microparticles as a wound healing system(Elsevier Science Bv, 2015) Eroglu, Ipek; Gokce, Evren H.; Tsapis, Nicolas; Tanriverdi, Sakine Tuncay; Gokce, Goksel; Fattal, Elias; Ozer, OzgenResveratrol (RSV) was incorporated into microparticles by spray drying to treat chronic wounds such as diabetic ulcers. RSV was chosen due to its defense mechanisms as the formation of free radicals delays the healing process. RSV was loaded into microparticles consisting of dipalmitoylphosphatidylcholine (DPPC) and hyaluronic acid (HA), a polysaccharide naturally present within the skin, known to contribute to the healing process. Microparticles were evaluated in terms of production yield, size distribution, encapsulation efficiency, morphology, specific surface area, thermal properties and water content. Spherical and homogenous microparticles (span <= 2) in a size range between 20 and 30 mu m were obtained with high encapsulation efficiency (>= 97%). The effect of enzymes (hyaluronidase, phospholipase and lipase) on RSV release showed a dose-dependent pattern followed by a slow release stage. Cytotoxicity/proliferation and oxidative stress parameters (glutathione, oxidized glutathione, glutathione peroxidase, malondialdehyde, superoxide dismutase) obtained from human dermal fibroblast cell cultures revealed that formulations increased cell proliferation and the presence of RSV decreased oxidation in cells. RSV-loaded HA-DPPC microparticles appear as a promising formulation for wound healing due to synergistic effect of the ingredients. (C) 2014 Elsevier B.V. All rights reserved.Öğe Glutathione Depletion by Buthionine Sulfoximine Induces Oxidative Damage to DNA in Organs of Rabbits in Vivo(Amer Chemical Soc, 2009) Gokce, Goksel; Ozsarlak-Sozer, Gonen; Oktay, Gulgun; Kirkali, Gueldal; Jaruga, Pawel; Dizdaroglu, Miral; Kerry, ZelihaGlutathione (GSH) exists in mammalian tissues in vivo at high concentrations and plays an important protective role against oxidatively induced damage to biological molecules, including DNA. We investigated oxidatively Induced damage to DNA by GSH depletion in different organs of rabbits in vivo. Rabbits were treated subcutaneously with buthionine sulfoximine (BSO), an effective GSH-depleting compound. GSH levels were measured in heart, brain, liver, and kidney of animals. BSO treatment significantly reduced GSH levels in heart, brain, and liver, but not in kidney. DNA was isolated from these tissues to test whether GSH depletion causes oxidatively induced DNA damage in vivo. Gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry with isotope dilution methods were applied to measure typical products of oxidatively induced damage in isolated DNA samples. Several such products were identified and quantified in all organs. BSO treatment caused significant formation of 8-hydroxyguanine, 2,6-diamino-4-hydroxy-5-formamidopyrimidine, 8-hydroxyadenine, and (5'S)-8,5'-cyclo-2'-deoxyadenosine in DNA of organs of rabbits. Animals were fed with the semiessential amino acid 2-aminoethanesulfonic acid (taurine) during BSO treatment. Taurine significantly inhibited GSH depletion and also formation of DNA products. Depletion of GSH correlated well with formation of DNA products, indicating the role of GSH in preventing oxidatively induced DNA damage. Our findings might contribute to the understanding of pathologies associated with DNA damage, oxidative stress, and/or defective antioxidant responses and improve our understanding of the effect of BSO in increasing the efficacy of anticancer therapeutics.Öğe In vitro release - In vivo microbiological and toxicological studies on ketoconazole lipid granules(Taylor & Francis Inc, 2007) Ozyazici, Mine; Gokce, Evren Homan; Ozer, Ozgen; Ay, Zeynep; Guneri, Tamer; Ertan, Gokhan; Gokce, Goksel; Metin, Dilek Yesim; Hilmioglu, Suleyha; Durmaz, Guliz; Yalcin, Ayfer; Pekeetin, Cetin; Ozyurt, DoganIn some multidrug therapy programs, ketoconazole (KTZ) may be administered with some antacids that could modify its dissolution rate and reduce its absorption, thus leading to therapeutic failures. The primary aim of this study was to evaluate the influence of Compritol HD5 ATO and Compritol 888 ATO on this interaction in comparison with commercial KTZ tablets. The second aim was to prepare lipid granules of KTZ that could be an alternative to the commercial formulation. Therefore, six KTZ sustained-release granules were prepared with different lipid concentrations, because they were found to be more suitable than tablets that are dissolved only in gastric medium. The results confirmed that the dissolution rate of KTZ granules was significantly reduced in the presence of antacids. The ideal formulation was selected as granules including 5% of Compritol lipids in relation to the suitability of the target profile. Therapeutic effects of orally administered, ideal KTZ granule formulations, and commercial tablets were evaluated in vivo by the experimental model of murine vulvo-vaginal candidiasis (VVC) with and without antacids. It was found that formulations were very effective on VVC, and the therapeutic effect decreased significantly in the presence of antacids. Histopathological studies were carried out for vagina, stomach, and liver tissues and hepatoxicity was also examined. The levels of reduced glutathione (GSH) were measured to assess the oxidative stress induced by KTZ and function of the liver. It was observed that orally administered formulations of KTZ were successful in treating candidiasis in mice without irritancy in stomach. However, liver tissues were damaged. The decreased GSH levels indicated toxicity in our study. This study suggested that in vitro release and in vivo microbiological-toxicological properties of KTZ were affected by antacids and drug-excipient interactions. Lipid granules of KTZ prepared with Compritol 888 ATO could be proposed as a new KTZ solid dosage form with optimum dissolution and therapeutic characteristics.Öğe Low-dose doxycycline inhibits hydrogen peroxide-induced oxidative stress, MMP-2 up-regulation and contractile dysfunction in human saphenous vein grafts(Dove Medical Press Ltd, 2019) Saeed, Mazen; Arun, Mehmet Zuhuri; Guzeloglu, Mehmet; Onursal, Ceylan; Gokce, Goksel; Korkmaz, Ceren Gonen; Reel, BuketBackground: Cardiopulmonary bypass (CPB) applied during coronary artery bypass grafting (CABG), promotes inflammation, generation of reactive oxygen species (ROS) and up-regulation of matrix metalloproteinases (MMPs). All these complications may lead to contractile dysfunction, restenosis and early graft failure, restricting long-term efficacy of bypass grafts. Low-dose doxycycline is a potent MMP inhibitor and ROS scavenger. In this study, we aimed to investigate the effects of doxycycline on ROS generation, MMP regulation and contractile dysfunction induced by H2O2 in human saphenous vein (HSV) grafts. Methods: HSV grafts (n=7) were divided into four groups after removing endothelial layer by mechanical scratching and incubated with 10 mu M H2O2 and/or 10 mu M doxycycline for 16 hrs. Untreated segments served as control. Concentration-response curves to noradrenaline (NA), potassium chloride (KCl), serotonin (5-HT) and papaverine were performed. Superoxide anion and other ROS levels were determined by using lucigenin- and luminol-enhanced chemiluminescence assays, respectively. Expression/activity of gelatinases (MMP-2/MMP-9) was examined by gelatin zymography. MMP-13 expression was evaluated by immunostaining/immunoscoring. Results: H2O2 incubation increased superoxide anion and other ROS levels. Doxycycline prevented these increments. H2O2 suppressed contractile responses to NA, KCl and 5-HT. Doxycycline ameliorated contractions to NA and KCl but not to 5-HT. H2O2 or doxycycline did not altered relaxation to papaverine. MMP-2 and MMP-13 expression increased with H2O2, but doxycycline inhibited MMP-2 up-regulation/activation. Conclusion: Low-dose doxycycline may have beneficial effects on increased oxidative stress, MMP up-regulation/activation and contractile dysfunction in HSV grafts.Öğe Omega-3 fatty acids inhibit oxidative stress in a rat model of liver regeneration(Korean Surgical Society, 2017) Firat, Ozgur; Makay, Ozer; Yeniay, Levent; Gokce, Goksel; Yenisey, Cigdem; Coker, AhmetPurpose: Lipid peroxidation and consequent reactive oxygen species in the setting of oxidative stress have crucial roles in liver regeneration, which may adversely affect the regeneration itself and lead to liver failure. The aim of the current study is to investigate whether omega-3 fatty acid supplementation inhibits oxidative stress in an experimental model of liver regeneration. Methods: Forty rats were allocated to four groups. Rats in group A received a sham operation. Rats in group B were subjected to right portal vein ligation (RPVL) and saline infusion. Rats in groups C and D were subjected to RPVL and total parenteral nutrition (TPN) with an all-in-one admixture containing a soybean oil based lipid emulsion. Rats in group D were additionally supplemented with omega-3 fatty acid infusion. Oxidative stresses in the blood and liver were measured by glutathione, superoxide dismutase, catalase, glutathione peroxidase, malondialdehyde, and nitric oxide. Results: Omega-3 supplementation to the TPN solution significantly corrected alterations in the blood and tissue concentrations of oxidants and anti-oxidants during regeneration (P < 0.05). Conclusion: Omega-3 fatty acid supplementation to the TPN solution revealed promising results in removal of oxidative stress that emerges during liver regeneration.Öğe Oxidative stress in relation to telomere length maintenance in vascular smooth muscle cells following balloon angioplasty(Springer, 2011) Ozsarlak-Sozer, Gonen; Kerry, Zeliha; Gokce, Goksel; Oran, Ismail; Topcu, ZekiTelomeres are specialized DNA-protein complexes found at the tips of linear chromosomes. In this study, we investigated the effects of oxidative stress on telomeric length distribution of proliferating vascular smooth muscle cells following balloon injury in single or combined treatment of rabbits with either buthionine sulfoximine or taurine. Exposure to oxidative stress increased the balloon injury whereas taurine treatment significantly diminished l-buthionine-sulfoximine-related intimal hyperplasia. Our results also showed that both variables had a significant influence on mean telomeric length distribution.Öğe Taurine inhibits increased MMP-2 expression in a model of oxidative stress induced by glutathione depletion in rabbit heart(Elsevier Science Bv, 2013) Sevin, Gulnur; Ozsarlak-Sozer, Gonen; Keles, Didem; Gokce, Goksel; Reel, Buket; Ozgur, Halil Hakan; Oktay, Gulgun; Kerry, ZelihaMatrix metalloproteinase enzymes (MMPs) activated by oxidative stress are involved in the pathogenesis of cardiovascular diseases. Glutathione (GSH) plays an important protective role against oxidatively induced damage in mammalian tissues. We investigated the possible role of gelatinases and the effect of the semiessential amino acid 2-aminoethanesulfonic acid (taurine) in oxidatively induced damage by GSH depletion in rabbit cardiac tissues. Rabbits were treated with buthionine sulfoximine (BSO), an effective GSH-depleting compound. BSO treatment significantly reduced GSH and increased MDA (malondialdehyde) levels. BSO treatment caused significant increase in proMMP-2 levels. MMP-9 (pro and active) expressions were not found in either treated- or untreated heart tissues. TIMP-1(endogenous inhibitor of MMP-9) and MT-MMP1 (endogenous activator of MMP-2) were not affected by BSO. Immunoscoring showed that MMP-2 expression significantly increased in hearts from BSO treated group but MMP-9 antibody did not show any significant positive immunostaining from all groups. Type I procollagen and total collagen did not significantly alter in heart tissues from all treatment groups. Taurine restored the increased MDA and the diminished GSH levels by BSO treatment. Pro MMP-2 expression was prevented by taurine. These results suggest that MMP-2 is a major gelanitase in rabbit hearts under oxidative stress and pharmacological inhibition of MMP-2 activation by taurine could represent a useful strategy for the prevention and/or treatment of different cardiovascular disorders. (C) 2013 Elsevier B.V. All rights reserved.Öğe Wound healing effects of collagen-laminin dermal matrix impregnated with resveratrol loaded hyaluronic acid-DPPC microparticles in diabetic rats(Elsevier Science Bv, 2017) Gokce, Evren H.; Tanriverdi, Sakine Tuncay; Eroglu, Ipek; Tsapis, Nicolas; Gokce, Goksel; Tekmen, Isil; Fattal, Elias; Ozer, OzgenAn alternative formulation for the treatment of diabetic foot wounds that heal slowly is a requirement in pharmaceutical field. The aim of this study was to develop a dermal matrix consisting of skin proteins and lipids with an antioxidant that will enhance healing and balance the oxidative stress in the diabetic wound area due to the high levels of glucose. Thus a novel three dimensional collagen-laminin porous dermal matrix was developed by lyophilization. Resveratrol-loaded hyaluronic acid and dipalmitoylpho sphatidylcholine microparticles were combined with this dermal matrix. Characterization, in vitro release, microbiological and in vivo studies were performed. Spherical microparticles were obtained with a high RSV encapsulation efficacy. The microparticles were well dispersed in the dermal matrix from the surface to deeper layers. Collagenase degraded dermal matrix, however the addition of RSV loaded microparticles delayed the degradation time. The release of RSV was sustained and reached 70% after 6 h. Histological changes and antioxidant parameters in different treatment groups were investigated in full-thickness excision diabetic rat model. Collagen fibers were intense and improved by the presence of formulation without any signs of inflammation. The highest healing score was obtained with the dermal matrix impregnated with RSV-microparticles with an increased antioxidant activity. Collagenlaminin dermal matrix with RSV-microparticles was synergistically effective due to presence of skin components in the formulation and controlled release achieved. This combination is a safe and promising option for the treatment of diabetic wounds requiring long recovery. (C) 2017 Elsevier B.V. All rights reserved.Öğe Zostera noltii extract lowers blood glucose and restores vascular function in diabetic rats(Bangladesh Pharmacological Soc, 2014) Haznedaroglu, Mehmet Zeki; Gokce, GokselThe antidiabetic effect of seagrass Zostera noltii extract was investigated through a crosstalk between its antioxidant and vasoprotective properties. The extract was orally administered to alloxan-diabetic rats (50, 150, 250 mg/kg body weight). Serum glucose was determined; liver and kidney functions, body weight, total leukocyte counts were measured; liver oxidative markers were assayed. Acetylcholine, phenylephrine and 5-HT responses were tested. eNOS levels and generation of ROS in aortic tissue were quantified. The extract of Z. noltii lowered blood glucose in all tested dose levels. Extract at a concentration of 50 mg/kg failed to preserve the levels of antioxidants and did not alter lipid peroxidation whereas higher doses improved liver oxidative status. Impaired acetylcholine relaxations, augmented phenylephrine and 5-HT contractions in alloxan-diabetic aortic rings were restored by Z. noltii treatment. This recovery was accompanied by increased eNOS synthesis and a reduction in ROS generation. The extract lowers blood glucose and prevents hyperglycemia-induced endothelial dysfunction in alloxan-diabetic rats.
