Person: ERZİK, CAN
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ERZİK
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CAN
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Publication Open Access Propylthiouracil-induced hypothyroidism protects ionizing radiation-induced multiple organ damage in rats(BIOSCIENTIFICA LTD, 2006-05) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sener, G.; Kabasakal, L.; Atasoy, B. M.; Erzik, C.; Velioglu-Ogunc, A.; Cetinel, S.; Contuk, G.; Gedik, N.; Yegen, B. C.The objective of this study was to examine the potential radioprotective properties of propylthiouracil (PTU)-induced hypothyroidism against oxidative organ damage induced by irradiation. Sprague-Dawley rats were pre-treated with saline or PTU (10 mg/kg i.p.) for 15 days, and were then exposed to whole-body irradiation (800 cGy). A group of rats were decapitated at 6 h after exposure to irradiation, while another group was followed for 72 h after irradiation, during which saline or PTU injections were repeated once daily. Lung, liver, kidney and ileum samples were obtained for the determination of malondialdehyde (MDA; an index of lipid peroxidation) and glutathione (GSH, an antioxidant) levels, myeloperoxidase activity (MPO; an index of tissue neutrophil accumulation) and collagen contents, while oxidant-induced DNA fragmentation was evaluated in the ileal tissues. All tissues were also examined microscopically and assayed for the production of reactive oxidants using chemiluminescence (CL). Lactate dehydrogenase (LDH), an indicator of tissue damage, and turnout necrosis factor-alpha (TNF alpha) were assayed in serum samples. Irradiation caused a significant decrease in GSH level, which was accompanied by significant increases in MDA levels, MPO activity, CL levels and collagen content of the tissues studied (P < 0.05-0.001). Similarly, serum TNFa and LDH were elevated in the irradiated rats as compared with the control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Our results suggested that PTU-induced hypothyroidism reduces oxidative damage in the lung, hepatic, renal and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.Publication Open Access Exosomes' profile in ankylosing spondylitis: A preliminary study(2023-01-01) ABACAR, KEREM YİĞİT; ATAGÜNDÜZ, MEHMET PAMİR; ERZİK, CAN; Karakaya E., Deniz R., ABACAR K. Y., ATAGÜNDÜZ M. P., ERZİK C.Objective: Ankylosing spondylitis (AS) is a chronic systemic inflammatory disease that leads to structural and functional im-pairments and reduced quality of life, with heterogeneous manifestations. The origin and possible role of extracellular vesicles represented by exosomes (EVexo) in the pathogenesis of AS were examined in this study. Materials and Methods: Extracellular vesicles (EVs) were isolated from serum from ten AS patients and ten healthy controls through Izon qEV2/35 nm columns. After assessing the isolate purity by bicinchoninic acid assay (BCA) and Enzyme-Linked ImmunoSorbent Assay (ELISA), the relationship between EVexo concentration and AS was tested by the BCA method. The EVexo surface markers were analyzed by flow cytometry (FC) to verify EVexo presence and reveal its origin. Results: In FC analysis, CD86+TSG101+ and CD3+TSG101+ exosome percentages of AS group were significantly higher than the control group (p<0.05). A significant difference was found between the AS and control groups in terms of CD3+IL17+ and CD3+IFNg+ and CD86+TNF alpha+ and CD86+IL12(p35)+ exosome percentages (p<0.01). Conclusion: The exosomes whose ratio increased in the AS process were derived from T cells expressing increased levels of IL-17A and IFNg in their membranes, and macrophages expressing increased levels of TNF alpha and IL-12(p35) in their membranes. The EVexo profile did not change according to the AS course.Publication Open Access Protective effects of St. John's wort in the hepatic ischemia/reperfusion injury in rats(AVES, 2018-09-28) VELİOĞLU ÖĞÜNÇ, AYLİZ; Atalay, Suleyman; Soylu, Belkis; Aykac, Asli; Ogunc, Ayliz Velioglu; Cetinel, Sule; Ozkan, Naziye; Erzik, Can; Sehirli, Ahmet OzerObjectives: The purpose of this study was to investigate possible protective effects of St. John's wort in the hepatic ischemia/reperfusion injury. Material and Methods: The hepatic artery, portal vein, and bile duct were all clamped for 45 minutes to induce ischemia in rats, and after that reperfusion for 1 hour. SJW was administrated orally, once a day for 3 days before ischemia/reperfusion. The aspartate aminotransferase, alanine aminotransferase, tumor necrosis factor, and interleukin levels were measured in the serum samples. Luminol chemiluminescence, lucigenin luminol chemiluminescence levels; myeloperoxidase. The sodium-potassium ATPase (Na+/K+ ATPase) activity was determined in the liver tissue, and caspase-3 and caspase-9 activity with the bcl-2/bax ratio were measured by the western blot analysis. Results: The St. John's wort administration recovered the aspartate aminotransferase, alanine aminotransferase, tumor necrosis factor, and IL-1 beta levels serum parameters meaningfully, while ischemia/reperfusion caused an increase in luminol chemiluminescence, lucigenin luminol chemiluminescence, myeloperoxidase, caspase-3, and caspase-9 activity and led to a decrease in the B-cell lymphoma-2/bcl-2-associated X protein (bcl-2/bax) ratio and the Na+/K+ ATPase activity. Conclusion: The obtained results indicate protective effects of St. John's wort on the ischemia/reperfusion injury through various mechanisms, and we are able to suggest that St. John's wort can clinically create a new therapeutic principle.Publication Open Access Effects of Circadian Rhythm Hormones Melatonin and 5-Methoxytryptophol on COXs, Raf-1 and STAT3(2018-08-01) ERZİK, CAN; Savtekin, Gokce; Serakinci, Nedime; Erzik, Can; Cetinel, Sule; Sehirli, Ahmet OzerPublication Open Access Nesfatin-1 alleviates extrahepatic cholestatic damage of liver in rats(ASSOC BASIC MEDICAL SCI FEDERATION BOSNIA & HERZEGOVINA SARAJEVO, 2016-11-10) ERZİK, CAN; Solmaz, Ali; Gulcicek, Osman Bilgin; Ercetin, Candas; Yigitbas, Hakan; Yavuz, Erkan; Arici, Sinan; Erzik, Can; Zengi, Oguzhan; Demirturk, Pelin; Celik, Atilla; Celebi, FatihObstructive jaundice (OJ) can be defined as cessation of bile flow into the small intestine due to benign or malignant changes. Nesfatin-1, recently discovered anorexigenic peptide derived from nucleobindin-2 in hypothalamic nuclei, was shown to have anti-inflammatory and antiapoptotic effects. This study is aimed to investigate the therapeutic effects of nesfatin-1 on OJ in rats. Twenty-four adult male Wistar-Hannover rats were randomly assigned to three groups: sham (n = 8), control (n = 8), and nesfatin (n = 8). After bile duct ligation, the study groups were treated with saline or nesfatin-1, for 10 days. Afterward, blood and liver tissue samples were obtained for biochemical analyses, measurement of cytokines, determination of the oxidative DNA damage, DNA fragmentation, and histopathologic analyses. Alanine aminotransferase and gamma-glutamyl transferase levels were decreased after the nesfatin treatment; however, these drops were statistically non-significant compared to control group (p = 0.345, p = 0.114). Malondialdehyde levels decreased significantly in nesfatin group compared to control group (p = 0.032). Decreases in interleukin-6 and tumor necrosis factor-a levels from the liver tissue samples were not statistically significant in nesfatin group compared to control group. The level of oxidative DNA damage was lower in nesfatin group, however this result was not statistically significant (p = 0.75). DNA fragmentation results of all groups were similar. Histopathological examination revealed that there was less neutrophil infiltration, edema, bile duct proliferation, hepatocyte necrosis, basement membrane damage, and parenchymal necrosis in nesfatin compared to control group. The nesfatin-1 treatment could alleviate cholestatic liver damage caused by OJ due to its anti-inflammatory and antioxidant effects.Publication Open Access Association of ERAP1, IL23R and PTGER4 Polymorphisms with Radiographic Severity of Ankylosing Spondylitis(2017-01-31) ERZİK, CAN; Ozen, Gulsen; Deniz, Rabia; Eren, Fatih; Erzik, Can; Unal, Ali Ugur; Yavuz, Sule; Aydin, Sibel Zehra; Inanc, Nevsun; Direskeneli, Haner; Atagunduz, PamirBackground: Radiographic severity of ankylosing spondylitis (AS) shows such great variance that some patients never develop syndesmophytes throughout the entire disease span, whereas some develop bamboo spine relatively early. Objective: To study the association between ERAP1 , IL23R and PTGER4 single nucleotide polymorphisms (SNPs) and radiographic severity in AS patients. Methods: rs27044 and rs30187 ( ERAP1 ), rs11209032 ( IL23R ) and rs10440635 ( PTGER4 ) SNPs were genotyped in 235 AS patients fulfilling the modified New York criteria. Patients were classified as mild- and severe-AS according to modified Stoke AS spinal score (mSASSS). Mild-AS is defined as having mSASSS of “0” following at least 10 years of disease duration. Severe-AS is defined as having mSASSS of >20 (patients with mild vertebral changes ( i.e. squaring or erosions) were omitted for clear stratification) regardless of disease duration. Results: The genotype distributions and allele frequencies of ERAP1 rs27044 and rs30187, IL23R rs11209032 and PTGER4 rs10440635 SNPs were similar in mild- (n=171, mSASSS=0, 55.6% HLA-B27 positive) and severe-AS patients (n=64, mSASSS=48.5±17.8, 73.4% HLA-B27 positive). After adjustment for clinical differences between groups (gender, disease duration, HLA-B27 and smoking status) by logistic regression analysis, none of the alleles in the investigated SNPs were found to be associated with radiographic severity of AS. Conclusion: In radiographically well-categorized AS patients, ERAP1 rs27044 and rs30187, IL23R rs11209032 and PTGER4 rs10440635 SNPs are not found to be associated with radiographic severity of AS.Publication Open Access Rethinking large group lectures – how far in this format(2022-05-01) SEVİM, MUSTAFA; ERZİK, CAN; YEGEN, BERRAK; GÜLPINAR, MEHMET ALİ; AKTURAN S., SEVİM M., ERZİK C., YEGEN B., GÜLPINAR M. A.Objective: The aim of this study is to determine the perceptions, attitudes, and behaviour of medical students and lecturers regarding the lectures and their effects on students’ learning behaviour. Materials and Methods: This was a qualitative study including multi-methods. Researchers observed lecture ambiance and activities in two courses. Lectures were observed and slide-presentations were evaluated. Additionally, in-depth and focus group interviews were conducted. Results: Two researchers attended and observed 75 lectures. The average number of attendees was 51.21. Eighty percent of lecturers did not introduce any activities to attract attention and prepare students for the lecture. Only 12% of lectures were taught interactively. Of the evaluated 43 (69.80%) slide-presentations, sufficient association or integration was not made between clinical and basic sciences. Conclusion: This study revealed that the lectures created negative feelings and thoughts in students and lecturers, and led to undesirable attitudes and behaviour. It is essential to focus on giving interactive lectures which aim at developing reasoning, decision-making, and evaluation competencies. The most significant factors determining students’ attendance and appraisal of the lectures were related to the preparation of the lecturers, the intensity of the content, integration between basic science and clinical science, and the presentation skills.Publication Open Access Radiation-induced oxidative injury of the ileum and colon is alleviated by glucagon-like peptide-1 and -2(ELSEVIER SCIENCE BV, 2015-04) ATASOY, BESTE MELEK; Deniz, Mustafa; Atasoy, Beste M.; Dane, Faysal; Can, Guray; Erzik, Can; Cetinel, Sule; Yegen, Berrak C.Purpose: The present study was conducted to characterize the possible therapeutic effects of glucagon-like peptide (GLP)-1 and GLP-2 against oxidative damage in the ileum and colon of irradiated rats. Methods and materials: Sprague-Dawley rats of both sexes received either a single dose of GLP-1 (0.1 nmol/kg, intraperitoneally, ip; n = 6) 10 min before abdominal irradiation (IR) or two consecutive doses of GLP-2 (7 nmol/kg, ip; n = 6) at 30 and 10 min before IR, while another group was administered vehicle (n = 6) 10 min before IR. Control rats (n = 6) received vehicle treatment without IR. On the fourth day of IR, samples from ileum and colon were removed for histological analysis, for the determination of myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, as well as DNA fragmentation ratio, an index of apoptosis. Results: IR-induced oxidative injury in the colonic tissue of vehicle-treated rats, evidenced by elevated MDA levels and MPO activity, as well as depleted colonic GSH levels, was reversed by GLP-2, while GLP-1 reduced IR-induced elevations in colonic MDA levels. IR-induced injury with elevated ileal MDA levels was reduced by GLP-1, while replenishment in GSH was observed in GLP-2-treated rats. Conclusion: Current findings suggest that GLP-1 and GLP-2 appear to have protective roles in the irradiation-induced oxidative damage of the gut by inhibiting neutrophil infiltration and subsequent activation of inflammatory mediators that induce lipid peroxidation. Copyright (C) 2015, The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.Publication Open Access A mutation in a functional Sp1 binding site of the telomerase RNA gene (hTERC) promoter in a patient with Paroxysmal Nocturnal Haemoglobinuria(2004-12) ERZİK, CAN; Keith, W Nicol; Vulliamy, Tom; Zhao, Jiangqin; Ar, Cem; Erzik, Can; Bilsland, Alan; Ulku, Birsen; Marrone, Anna; Mason, Philip J; Bessler, Monica; Serakinci, Nedime; Dokal, InderjeetPublication Open Access Anti-inflammatory, antioxidant and neuroprotective effects of niacin on mild traumatic brain injury in rats(2023-01-01) KOYUNCUOĞLU, TÜRKAN; AKAKIN, DİLEK; ERZİK, CAN; YÜKSEL, MERAL; YEGEN, BERRAK; Ozaydin D., Bektasoglu P. K., Koyuncuoglu T., Ozkaya S. C., Koroglu A. K., AKAKIN D., ERZİK C., YÜKSEL M., YEGEN B., Gurer B.AIM: To study the effects of niacin, a water-soluble vitamin, on inflammation, oxidative stress and apoptotic processes observed after mild traumatic brain injury (TBI). MATERIAL and METHODS: A total of 25 Wistar albino male rats were randomly divided into control (n=9), TBI + Placebo group (n=9), TBI + niacin (500 mg/kg; n=7) groups. Mild TBI was performed under anesthesia by dropping a 300 g weight from a height of 1 meter onto the skull. Behavioral tests were applied before and 24 hours after TBI. Luminol and lucigenin levels and tissue cytokine levels were measured. Histopathological damage was scored in brain tissue. RESULTS: After mild TBI, luminol and lucigenin levels were increased (p<0.001), and their levels were decreased with niacin treatment (p<0.01-p<0.001). An increased score was obtained with trauma in the tail suspension test (p<0.01), showing depressive behavior. The number of entries to arms in Y-maze test were decreased in TBI group compared to pre-traumatic values (p<0.01), while discrimination (p<0.05) and recognition indices (p<0.05) in object recognition test were decreased with trauma, but niacin treatment did not change the outcomes in behavioral tests. Levels of the anti-inflammatory cytokine IL-10 were decreased with trauma, and increased with niacin treatment (p<0.05). The histological damage score was increased with trauma (p<0.001), and decreased with niacin treatment in the cortex (p<0.05), and hippocampal dentate gyrus region (p<0.01). CONCLUSION: Niacin treatment after mild TBI inhibited trauma-induced production of reactive oxygen derivatives and elevated the anti-inflammatory IL-10 level. Niacin treatment ameliorated the histopathologically evident damage.