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Öğe Comparison of the Protective Effects of Prostaglandin Analogues in the Ischemia and Reperfusion Model of Rabbit Eyes(Int Press Editing Centre Inc, 2009) Emre, Sinan; Gul, Mehmet; Ates, Burhan; Esrefoglu, Mukaddes; Koc, Bekir; Erdogan, Ali; Yesilada, ElifThis study was planned to investigate the neuroprotective potentials of three commercially available prostaglandin analogues (PGA), in the ischemia and reperfusion model (I/R). Thirty New Zealand rabbits were divided into 5 groups and except for the control group (non-ischemic, non-treated), 0.9% NaCl, bimatoprost, latanoprost, or travoprost were applied to both eyes of animals of the respective groups for 1 week. At the end of treatment, ischemia was induced in both eyes of the 4 treatment groups by anterior chamber irrigation of the animals for 60 min. Following 24 h reperfusion, the animals were sacrified. Enucleated eyes and retinal tissues were investigated by light microscopy, electron microscopy, immunohistochemicstry for retinal histopathology, intracellular and apoptotic cells and by retinal morphometry. Vitreous samples were biochemically investigated for probable role of reactive oxygen species, by measuring xanthine oxidase (XO) activity. Analysis of morphometric measurements and vitreous XO activity revealed significant differences between the PGA-treated groups and the NaCl-treated group (P<0.05). Similarly, apoptotic cell counts in different retinal layers showed that PGA-treated groups had fewer apoptotic cells in all retinal layers than the NaCl-treated ischemic group (P<0.05). PGA may have high protective potential for different retinal layers and cells. Biochemical analysis of vitreous showed that all PGAs decreased vitreous XO activity significantly compared to the NaCl-treated group (P<0.05). However we could not find any statistically significant differences among the analogues. PGAs may reduce the injury induced by I/R, through the inhibition of XO activity, and it seems that their effects are elicited through numerous pathways.Öğe The effects of caffeic acid phenethyl ester and melatonin on age-related vascular remodeling and cardiac damage(Wiley, 2011) Esrefoglu, Mukaddes; Gul, Mehmet; Ates, Burhan; Erdogan, AliOxidative stress has been implicated with cardiovascular aging. Most antioxidant intervention studies have involved long-term treatments as a potential means to eliminate age-related oxidative damage in many systems. In the present study, not only light and electron microscopic pictures of the heart and thoracic aorta of young and aged and, caffeic acid phenethyl ester (CAPE) and melatonin and administered aged Sprague Dawley rats, but also antioxidant system status was evaluated. Significantly elevated levels of malondialdehyde (MDA) were observed in the heart and thoracic aorta of aged rats (P < 0.05 and P < 0.001, respectively). Chronic melatonin and CAPE administration significantly reduced the levels of MDA in the heart (P = 0.005 and P = 0.05, respectively) and thoracic aorta (P < 0.001 and P < 0.05, respectively) of aged animals. Additionally, melatonin and CAPE were efficient in stimulating the activities and increasing the levels of the antioxidant enzymes in the heart and aorta. Prominent electron microscopic alterations in cardiac myocytes such as nuclear irregularity, mitochondrial degeneration, myofilament disorganization and disruption, and lipofuscin accumulation were observed in aged rats. The main age-related histologic modifications observed in aorta were irregularity in endothelial cells and their nuclei, divergence of endothelial cells from basement membrane and neighboring cells, and elastic fibril fragmentation and reduction. Melatonin and CAPE obviously reduced these alterations in both heart and aorta of aged rats. Taking the results together, we suggest that supplemental administration of CAPE and melatonin is beneficial in delaying age-related cellular damage in cardiovascular system.Öğe GMI-based biosensor for the detection and quantification of doxorubicin anticancer drugs labeled to Fe3O4 superparamagnetic nanoparticles(Elsevier Science Sa, 2024) Kirat, Gokhan; Erdogan, Ali; Aksan, Mehmet AliWe present the results of research on a Co -based giant magnetoimpedance (GMI) biosensor for Fe 3 O 4 -labelled doxorubicin (DOX) anticancer drugs. Co 62 Fe 5 Ni 4 Si 15 B 14 ribbons were used as biosensing material for test solutions containing different concentrations of DOX. The plain ribbon, ribbon +Fe 3 O 4 and ribbon +DOX2 samples exhibited low coercivity ( H c ), high saturation magnetization ( M s ) and low anisotropy ( H k ). The GMI ratio ( Delta Z / Z ) increased from 33% to 38% with the increase of doxorubicin content in the ribbon. It was found that the Delta Z / Z ratio first increased rapidly up to a frequency of -2 MHz, and then decreased slowly as the frequency increased. While the magnetic field dependent Delta Z / Z has a single peak at 1 MHz, it has a double peak at 5 MHz. It was found that the peak height of Delta Z/Z in the ribbons with test solution of 20 ng/ml and 50 ng/ml increased by -3% and -6%, respectively, compared to the ribbon without test solution. Then the Delta Z / Z ratio decreased very rapidly with the increase of the applied external magnetic fields. The frequency -dependent GMI sensitivity ( eta) increased with increasing frequency and reached a maximum value at a critical frequency (-1.6 MHz), after which it decreased. The detection sensitivity of the GMI biosensor ( xi ) increased rapidly with increasing doxorubicin concentration up to -80 ng/ml and then remained almost unchanged. The results show that doxorubicin (DOX +Fe 3 O 4 ), used as an anticancer drug, can be effectively detected even at low concentrations using the GMI based sensors fabricated in this study.Öğe Potent protective effect of apricot and ?-carotene on methotrexate-induced intestinal oxidative damage in rats(Pergamon-Elsevier Science Ltd, 2008) Vardi, Nigar; Parlakpinar, Hakan; Ozturk, Feral; Ates, Burhan; Gul, Mehmet; Cetin, Asli; Erdogan, AliSeveral studies have well confirmed the contribution of oxidative stress in the pathogenesis of methotrexate (MTX)-induced damage in the small intestine. Many agents have been tried experimentally to reduce or inhibit the oxidative stress. To our knowledge, there is no study about apricot consumption on the MTX-induced damage in the small intestine. The aim of this study was to determine the possible protective effects of apricot and beta-carotene on MTX-induced intestinal damage in rats. The rats were randomly divided into seven groups as follows; I-control group; H-apricot group; III-beta-carotene group; IV-MTX group: V-apricot + MTX group; VI-beta-carotene + MTX group and VII-apricot + beta-carotene + MTX group. In the MTX group; fusion and shortening in the villus, epithelial desquamation, crypt loss, inflammatory cell infiltration in the lamina propria, goblet cell depletion and microvillar damage were observed in the small intestine. Parallel to histological results, malondialdehyde (MDA) content and myeloperoxidase (MPO) activity were found to be increased, whereas superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GP-x) activities and glutathione (GSH) content were decreased in the MTX group. However, single or combined application of apricot and p-carotene ameliorated all of these hazordous effects in antioxidant system in MTX-treated groups. In conclusion, our results demonstrate that apricot and/or beta-carotene treatment may protect the impairment of oxidative stress and ameliorate MTX-induced intestine damage at biochemical and histological levels. (C) 2008 Elsevier Ltd. All rights reserved.Öğe Preparation of the L-Asparaginase-Based Biosensor With Polyimide Membrane Electrode for Monitoring L-Asparagine Levels in Leukemia(Taylor & Francis As, 2014) Erdogan, Ali; Koytepe, Suleyman; Ates, Burhan; Yilmaz, Ismet; Seckin, TurgayPolyimide based amperometric biosensor was developed for the in vitro determination of L-asparagine in serum samples for monitoring L-asparagine levels in leukemia. First, polyimide from pyromellitic dianhydride and 4,4-oxydianiline (ODA) was prepared. This prepared polyimide was used as an immobilization membrane of L-asparaginase (L-ASNase) for L-ASNase-polyimide-coated electrodes. From the amperometric results for the polyimide electrode, it is concluded that polyimide membrane containing L-asparaginase can be used as a membrane for asparagine detection in the presence of large concentration of interferences, because of its strong adherence to the electrode surface, easy preparation, chemical stability, selectivity, and very high statistical confidence (R=0.9988).Öğe Protective Effect of ?-Carotene on Methotrexate-Induced Oxidative Liver Damage(Sage Publications Inc, 2010) Vardi, Nigar; Parlakpinar, Hakan; Cetin, Asli; Erdogan, Ali; Ozturk, I. CetinIn this study, the authors aimed to investigate the role of oxidative stress on the hepatic damage caused by methotrexate (MTX) and the possible protective effects of beta-carotene against this damage. The rats were divided into four groups as control, MTX (20 mg/kg ip), beta-carotene (10 mg/kg/day ip) | MTX, and beta-carotene. Histopathologic alterations were evaluated for defining the liver damage. The tissue, malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GP-x) contents and serum aspartate aminotransferase (AST) and alanine aminotranferase (ALT) activities were also examined. Histopathologic damage for each group score findings have been determined as control: 0.66 +/- 0.33; MTX: 7.0 +/- 0.68; beta-carotene | MTX: 3.3 +/- 0.42; and beta-carotene: 0.5 +/- 0.3. In the MTX-treated group, MDA, AST, and ALT values were increased, while SOD and GP-x values were decreased compared with the control group. In the beta-carotene + MTX-treated group, AST and ALT values significantly decreased, while all other parameters were similar to the control group. This study shows that beta-carotene has a protective effect on MTX-induced oxidative hepatic damage. Consequently, it seems that an antioxidant agents like beta-carotene may be useful in decreasing the side effects of chemotherapy.Öğe Protective effect of dietary apricot kernel oil supplementation on cholesterol levels and antioxidant status of liver in hypercholesteremic rats(Wfl Publ, 2009) Kutlu, Tuerkan; Durmaz, Goekhan; Ates, Burhan; Erdogan, AliApricot kernel oil is a rich source of MUFA and PUFA, including mainly oleic (about 70%) and linoleic acids, respectively. In addition, apricot kernel oil could be considered as a good source of bioactive compounds such as tocopherols and phytosterols consisting mainly of they gamma-isomer and beta-sitosterol, respectively. Given to its high content of oleic acid, apricot kernel oil is considered as a healthy supplement in diet. In the present study, we investigated the effects of apricot kernel oil supplementation on cholesterol and malondialdehyde (MDA) levels and glutathione peroxidase (GPx) and catalase (CAT) activity in hypercholesteremic rats. Hypercholesteremia was produced by feeding rats with a semisynthetic diet that contained high cholesterol and cholic acid. A high cholesterol diet caused a decrease in CAT and GPx activity, while apricot kernel oil caused a significant activity increase of these enzymes (P < 0.05). The group fed with apricot kernel oil supplementation showed higher enzyme activities than sunflower oil groups irrespective of cholesterol (P < 0.05). Results of the present study indicate that apricot kernel oil causes improvement in liver antioxidant status of rats in comparison to sunflower oil which is a commonly consumed vegetable oil.Öğe Ruthenium, rhodium and iridium complexes of a silyl-substituted N-heterocyclic carbene ligand and their catalytic performance in hydrosilylation of terminal alkynes(Elsevier Science Sa, 2023) Mumcu, Akin; Karatas, Mert Olgun; Ozdemir, Namik; Erdogan, Ali; Kucukbay, HasanHerein, [Ru(NHC)(p-cymene)Cl-2] (3) and [MCl(NHC)(cod)] (M=Rh (4) or Ir (5)) (cod=1,5-cyclooctadiene) complexes of a silyl-substituted N-heterocyclic carbene ligand (NHC) have been prepared by the transmetalation reaction between Ag-NHC (2) and corresponding starting metal compound. The characterization of the complexes has been completed by NMR spectroscopy and elemental analyses. Solid state structures of Ag- (2) and Rh-NHC (4) have also been determined by single crystal X-ray analysis. [RhCl(NHC)(CO)(2)] type bis-carbonyl complex (6) has also been prepared and CO stretching frequencies pointed the strong s-donor ability of the silyl-substituted NHC. The catalytic activity of all complexes have been examined in hydrosilylation of terminal alkynes. Among the complexes, Ir-NHC has been found out as active catalyst with around 90% conversion and beta-(Z) selectivity at room temperature. Further studies revealed that this complex is able to maintain its stability in catalytic reaction conditions, chemoselective to alkynes in the presence of alkenes, and operable in scale-up reactions. In contrast, bis-carbonyl Rh-NHC performed 82% beta-(Z) selectivity with full conversion of alkyne in first 4 h of reaction, but when reaction time was extended to 24 h, almost all beta-(Z) vinylsilane isomerised to thermodynamically more stable beta-(E). (c) 2023 Elsevier B.V. All rights reserved.Öğe Silver and ruthenium complexes with anthracene functionalized N-heterocyclic carbene ligands: catalytic and cytotoxicity properties(Springer, 2024) Karatas, Mert Olgun; Kelestemur, Unzile; Mumcu, Akin; Ozdemir, Namik; Erdogan, Ali; Kucukbay, HasanIn this study, we have synthesized two Ag (2a and 2b) and two Ru (3a and 3b) complexes with anthracene substituted N-heterocyclic carbene (NHC) ligands. Ag-NHC complexes have been synthesized by the interaction of corresponding benzimidazolium chloride and Ag2O. Ru-NHC complexes have been synthesized by the transmetalation reaction between corresponding Ag-NHC and [RuCl2(p-cymene)]2 dimer. The synthesized complexes have been characterized by elemental analysis, NMR (1H and 13C NMR), and mass (high resolution mass spectroscopy, HRMS) spectroscopic techniques. In order to assess the catalytic potential of the Ru-NHC complexes, we have conducted experiments involving the hydrosilylation of terminal alkynes. Both complexes have exhibited a moderate level of catalytic activity, achieving conversions ranging from 70 to 90%, along with a substantial beta-(Z) selectivity within the range of 80-90%. Furthermore, we have also subjected the benzimidazolium chlorides (1a and 1b), Ag-NHCs and Ru-NHCs to cytotoxicity testing using human breast cancer cells (MCF-7) and human colorectal cancer cells (Caco-2). The results of these assays have demonstrated that all compounds strongly inhibit the proliferation of both cell lines.Öğe Synthesis of the Coumarin-Containing Porous Silica as Column Packing Material(Springer, 2016) Kazmaz, Emine Sura; Karatas, Mert Olgun; Koytepe, Suleyman; Ates, Burhan; Erdogan, Ali; Alici, Bulent; Seckin, TurgayFor the synthesis of the coumarin based column packing materials, amino functionalized porous silica was prepared from the modification of silica with 3-aminopropyl triethoxysilane. This amino functional silica was reacted with 4-chloromethyl-7,8-dihydroxycoumarin. The produced silica based column packing material was characterized by spectral techniques, scanning electron microscope, X-ray diffraction analysis (X-ray), N-2 adsorption isotherms and thermal analysis techniques. The effect of coumarin group on the silica structure and separation properties as well as the thermal stability of materials was investigated. Average particle diameters, pore size and surface areas of the coumarin based silica particles were 2680 +/- A 750 mu m, similar to 33 nm and 118 +/- A 6 m(2)/g, respectively. 240 mm x 4.6 mm high performance liquid chromatography column was packed with coumarin functionalized porous silica. Then, this column was applied to the separation of similar structure aromatic compounds such as benzene, toluene and xylene. Column performance was investigated by measuring time of continuous use peak asymmetry, resolution, and selectivity. Chromatographic resolutions of coumarin-modified packing material were in the range of 2.28-2.35. According to these data, for the separation of aromatic compounds, while pure silica does not provide effective separation, coumarin based column packing material has showed good separation and selectivity.
