Person: VELİOĞLU ÖĞÜNÇ, AYLİZ
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VELİOĞLU ÖĞÜNÇ
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AYLİZ
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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 Effect of Vitamin D Deficiency and Replacement on Endothelial Function in Asymptomatic Subjects(ENDOCRINE SOC, 2009-10-01) VELİOĞLU ÖĞÜNÇ, AYLİZ; Tarcin, Ozlem; Yavuz, Dilek Gogas; Ozben, Beste; Telli, Ahu; Ogunc, Ayliz Velioglu; Yuksel, Meral; Toprak, Ahmet; Yazici, Dilek; Sancak, Seda; Deyneli, Oguzhan; Akalin, SemaContext: Vitamin D receptors are present in many tissues. Hypovitaminosis D is considered to be a risk factor for atherosclerosis. Objective: This study explores the effects of vitamin D replacement on insulin sensitivity, endothelial function, inflammation, oxidative stress, and leptin in vitamin D-deficient subjects. Design, Setting, and Patients: Twenty-three asymptomatic vitamin D-deficient subjects with 25-hydroxyvitamin D [25(OH)D] levels below 25 nmol/liter were compared with a control group that had a mean 25(OH)D level of 75 nmol/liter. The vitamin D-deficient group received 300,000 IU im monthly for 3 months. The following parameters were evaluated before and after treatment: vitamin D metabolites, leptin, endothelial function by brachial artery flow mediated dilatation (FMD), insulin sensitivity index based on oral glucose tolerance test, and lipid peroxidation as measures of thiobarbituric acid reactive substances (TBARS). Results: FMD measurements were significantly lower in 25(OH)D-deficient subjects than controls (P = 0.001) and improved after replacement therapy (P = 0.002). Posttreatment values of TBARS were significantly lower than pretreatment levels (P < 0.001). A positive correlation between FMD and 25(OH)D (r = 0.45; P = 0.001) and a negative correlation between FMD and TBARS (r = -0.28; P < 0.05) were observed. There was a significant increase in leptin levels after therapy, and the leptin levels were positively correlated with 25(OH)D levels (r = 0.45; P < 0.05). Conclusions: This study shows that 25(OH)D deficiency is associated with endothelial dysfunction and increased lipid peroxidation. Replacement of vitamin D has favorable effects on endothelial function. Vitamin D deficiency can be seen as an independent risk factor of atherosclerosis. Hypovitaminosis D-associated endothelial dysfunction may predispose to higher rates of cardiovascular disease in the winter. (J Clin Endocrinol Metab 94: 4023-4030, 2009)Publication Open Access Effects of ACE inhibition and Angiotensin II receptor blockade on glomerular basement membrane protein excretion and charge selectivity in Type 2 diabetic patients(J R A A S LTD, 2006-06) VELİOĞLU ÖĞÜNÇ, AYLİZ; Deyneli, Oguzhan; Yavuz, Dilek; Velioglu, Ayliz; Cacina, Hasan; Aksoy, Nihal; Haklar, Goncaguel; Taga, Yavuz; Akalin, SemaAngiotensin-converting enzyme (ACE) inhibitors may reduce urinary albumin excretion (UAE) by decreasing glomerular pressure and increasing glomerular charge selectivity through preservation of glycosaminoglycans. The effect of Angiotensin II antagonism on glomerular charge selectivity remains to be determined. The aim of this study was to compare the effects of an AT, blocker losartan and an ACE inhibitor (ACE-I) enalapril on UAE, extracellular matrix proteins, glycosaminoglycan excretion(U-GAG) and red blood cell anionic charge (RBCCh) which are the indirect markers of glomerular basement membrane anionic content in hypertensive Type 2 diabetic patients. Twenty-four patients were randomised into two groups and received either enalapril (5-20 mg/d) or losartan (50-100 mg/d). All parameters were measured at baseline and after six months of treatment. At the end of six months, systolic and diastolic blood pressures (BP), UAE rates, U-GAG excretion and RBCCh were significantly and equally reduced in both treatment groups compared with baseline. RBCCh was negatively correlated with UAE (r = -0.57, p < 0.0001) and U-GAG excretion (r = -0.57, p < 0.0001); UAE was correlated with U-GAG excretion (r = 0.58, p < 0.0001). In conclusion, enalapril and losartan treatment were equally effective in reducing BP, UAE as well as U-GAG excretion and preserving RBCCh in hypertensive Type 2 diabetic patients. ACE inhibition and AT(1)-receptor blockade may have favourable effects on preserving glomerular anionic content in hypertensive diabetic patients.Publication Open Access Arginase activity and nitric oxide levels in patients with obstructive sleep apnea syndrome(2014-04-02) VELİOĞLU ÖĞÜNÇ, AYLİZ; Yuksel, M; Okur, Hk; Pelin, Z; Ogunc, Av; Ozturk, LPublication 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 Protective Effect of Nigella Sativa Oil Against Indomethacin-Related Small Intestine and Gastric Mucosal Damage in Rats(AVES, 2021-04-26) VELİOĞLU ÖĞÜNÇ, AYLİZ; Gunay, Emre; Ozkan, Erkan; Abuoglu, Haci Hasan; Aykac, Asli; Ogunc, Ayliz Velioglu; Karanlik, Buse; Cetinel, Sule; Sehirli, Ahmet OzerBACKGROUND/AIMS The aim of this study was to investigate the effects of Nigella sativa (NS) oil form on reducing the damage caused by indomethacin in the stomach and duodenum of rats owing to their antioxidant and anti-inflammatory properties. MATERIAL and METHODS The rats were divided into 4 groups: group 1, saline-treated control group; group 2, NS-treated control group; group 3, saline-treated ulcer group and ulcers caused by indomethacin (30 mg/kg) and administration of physiological serum; group 4, NS-treated ulcer group, which is the group receiving NS oil after administration of indomethacin. At the end of the study, blood samples collected from animals were examined for tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and glutathione (GSH), malondialdehyde (MDA) levels and myeloperoxidase (MPO),and Na+/K+-ATPase activities in gastric and intestinal tissue samples. RESULTS Levels of TNF-alpha and IL-1 beta in serum and MDA and MPO values in tissue were found to be higher in the saline-treated ulcer group than in the saline-treated control group. In addition, tissue GSH and Na+/K+-ATPase levels were found to be lower. These values were found to be reversed when comparing NS-treated ulcer group to saline-treated ulcer group. Histopathological findings showed epithelial regeneration and improvement instead of dense tissue damage. CONCLUSION The strong antioxidant and anti-inflammatory effects of NS against potential small intestine and gastric damage were shown using an experimental indomethacin-induced ulcer model in rats. Hence, our study suggests that NS used together with indomethacin can prevent gastrointestinal damage; thus, this agent can create a new clinical therapeutic principle.Publication Open Access The Influence of N-Acetylcysteine Alone and in Combination with Angiotensin Converting Enzyme Inhibitor and Angiotensin Receptor Antagonist on Systemic and Tissue Levels in Rats with Experimentally-Induced Chronic Renal Failure(ZOOLOGICAL SOC PAKISTAN, 2020) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sehirli, Ahmet Ozer; Sayiner, Serkan; Velioglu-Ogunc, Ayliz; Serakinci, Nedime; Eksioglu-Demiralp, Emel; Yegen, Berrak; Ercan, Feriha; Sener, GokselThe protective effects of ACE inhibitor, Captopril, and angiotensin receptor blocker, Valsartan, were evaluated in the treatment of chronic renal failure (CRF) with and without the presence of N-acetylcysteine (NAC). The renal mass of Wistar albino rats was reduced at a rate of 5/6. Captopril, Valsartan and NAC were applied intra-peritoneal alone or in combination. Blood pressure and heart rate were monitored at weekly intervals over a period of six weeks. Serum creatinine, blood urea nitrogen (BUN), lactate dehydrogenase (LDH) activity, cytokines (TNF-alpha, IL-1 beta, IL-6) concentrations, urinary volume, creatinine, and both serum and urinary electrolyte levels were measured. In addition, the apoptosis rate of white blood cells was analysed from plasma samples. Tissue samples from the brain, heart, aorta and kidneys were used for analysis of the collagen content besides tissue luminol, lucigenin, malondialdehyde (MDA) and glutathione (GSH) levels. A significant difference was determined between the CRF group and the control group with regard to heart rate, blood pressure, serum creatinine, BUN, LDH, cytokines and urinary electrolyte levels. Furthermore, monocyte and neutrophil apoptosis, tissue luminol, lucigenin, malondialdehyde and collagen levels were found to increase. Tissue glutathione levels were found to decrease indicating oxidative damage. These results indicate that oxidative mechanisms induce tissue damage in CRF, and the angiotensin receptor blocker, Valsartan, improved oxidative tissue damage when used in combination with the ACE inhibitor, Captopril or NAC, yielded better results and could be a novel approach for the treatment of CRF when used in combination with anti-oxidants.Publication Open Access Matrix Metalloproteinase-9 Level and Gene Polymorphism in Sleep Disordered Breathing Patients with or without Cardiovascular Disorders(AVES YAYINCILIK, 2013-03-05) VELİOĞLU ÖĞÜNÇ, AYLİZ; Yuksel, Meral; Kuzu-Okur, Hacer; Velioglu-Ogunc, Ayliz; Pelin, ZerrinObjective: Obstructive sleep apnea syndrome (OSAS) is associated with increased cardiovascular morbidity and mortality. We aimed to investigate the matrix metalloproteinase-9 (MMP-9) level and MMP-9 gene polymorphism in sleep apnea patients with or without cardiovascular disease. Study Design: Case-control study. Material and Methods: Two hundred nine patients [Mean age (+/- SD), 47 (+/- 12) yrs; M/F, 170/39] diagnosed with sleep-disordered breathing were included in the study. Serum MMP-9 level was performed using enzyme-linked immunosorbant assay (ELISA) and MMP-9 gene polymorphism with polymerase chain reaction-restriction fragment length polymorphism. We divided the patient group into two subgroups: (1) patients with confirmed cardiovascular disease, i.e. CV-P Group and (2) patients without cardiovascular disease, CV-N Group. We compared all parameters between the two groups. Results: There were 56 OSAS patients with cardiovascular disorder (CV-positive group) and 153 OSAS patients without cardiovascular disorder (CV-negative group). CC, CT and TT genotype distributions between groups were similar [31 (55%), 25 (45%), 0 (0%) vs 88 (57%), 61 (40%), 4 (3%); respectively, p>0.05]. MMP-9 level was significantly higher in CV-P patients (442.7 +/- 139.3 pg/mL) than in CV-N patients (364.4 +/- 165.0 pg/mL; p=0.0018). Conclusion: Our results showed that the presence of MMP-9 polymorphism was not associated with cardiovascular disease. MMP-9 level was higher in OSAS patients with cardiovascular disorders than without cardiovascular disorders. Finally, MMP-9 genotype was not associated with serum MMP-9 levels.Publication Open Access The protective effect of spironolactone and role of the Na+/K+-ATPase pump on intestinal ischemia/reperfusion injury(MARMARA UNIV, 2018-07-02) VELİOĞLU ÖĞÜNÇ, AYLİZ; Akyuz, Cebrail; Uzun, Orhan; Sunamak, Oguzhan; Velioglu-Ogunc, Ayliz; Cetinel, Sule; Sehirli, Ahmet OzerThe aim of this study was to evaluate the possible protective effect of spironolactone (SPL) and role of the Na-K ATPase pump on intestinal ischemia/reperfusion injury. In our study, the period of ischemia was established by clamping the mesenteric artery for 45 minunder anesthesia in Wistar albino rats and the animals left for reperfusion at the end of this period were decapitated after one hour. Spironolactone (20 mg kg(-1)) was administered orally for three days before ischemia, 30 minbefore ischemia. The control group rats were subjected to the Sham operation and administered saline solution. TNF-alpha and IL-1 beta levels were measured in the serum samples. Ileal Na+/K+-ATPase, myeloperoxidase (MPO) analysis were performed. Structural injury was assessed histopathologically. Ischemia/reperfusion increased serum TNF-alpha and IL-1 beta levels together with MPO activity, whereas these values were maintained at the control group levels through SPL activation. However, ischemia/reperfusion decreased Na+/K+-ATPase activity in ileal tissues; however, these parameters were found to be significantly increased with SPL activation. The protective effect of SPL against ischemia/reperfusion injury by different mechanisms, mainly the activity of the Na+/K+-ATPase pump, suggests that this nontoxic agent may constitute a new clinical therapeutic principle.Publication Open Access Effects of ACE inhibition and AT(1)-receptor antagonism on endothelial function and insulin sensitivity in essential hypertensive patients(SAGE PUBLICATIONS LTD, 2003-09) VELİOĞLU ÖĞÜNÇ, AYLİZ; Yavuz, D; Koc, M; Toprak, A; Akpinar, I; Velioglu, A; Deyneli, O; Haklar, G; Akalin, SObjective Disturbed endothelial function is closely associated with hyperinsulinaemia and insulin resistance in essential hypertension. The alms of this study were: 1) to evaluate whether the two alternative drugs, angiotensin-converting enzyme (ACE) inhibitors and Angiotensin 11 (Ang 11) antagonists, had comparable effects on glucose metabolism and endothelial function. 2) to determine whether they improve endothelial dysfunction through modulating insulin resistance and oxidative stress. Study design and methods Essential hypertensive patients were randomised into two groups: Twelve (nine patients in final analysis) patients were given enalapril (enalapril group), and twelve (nine patients in final analysis) were given losartan (losartan group). Twelve sex- and age-matched normotensive volunteers were included as controls. Before and after six months of treatment, endothelial function, insulin sensitivity and lipid peroxidation (TBARs) and NO metabolites (NOx) were evaluated. Results Endothelial function, measured as flow mediated dilatation (FMD), was improved in both of the treatment groups (p=0.0001). Calculated insulin sensitivity index also improved in the enalapril-treated group (p=0.05) but not in the losartan-treated group, compared with baseline levels. TBARS values decreased significantly in the enalapril group compared with baseline levels (p<0.001). FMD was positively correlated with insulin sensitivity index (r=0.32, p<0.05) and NOx levels (r=0.39, p=0.01) and negatively correlated with TBARS levels (r=-0.53, p=0.0002) in hypertensive patients. Conclusion Inhibition of the renin-angiotensin system, either with ACE inhibitors or AT(1)-receptor blockers improves endothelial dysfunction. ACE inhibition has prominent effects on improving insulin sensitivity and decreasing oxidative stress in essential hypertensive patients.