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GÜLER, ERAY METİN

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Kurumdan Ayrılmıştır

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Tıp Fakültesi

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ERAY METİN

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GÜLER

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Now showing 1 - 10 of 13

Open Access
Serum obestatin and omentin levels in patients with diabetic nephropathy
(2017-02-01) ZORLU, MEHMET; KISKAC, MUHARREM; Gueler, ERAY METİN; GUELTEPE, I.; YAVUZ, E.; CELIK, K.; KOCYIGIT, ABDÜRRAHİM; ZORLU, MEHMET; KISKAÇ, MUHARREM; GÜLER, ERAY METİN; KOÇYİĞİT, ABDÜRRAHİM
Introduction: Diabetic nephropathy is the leading cause of chronic kidney disease and accounts for almost 45% of all new patients requiring renal replacement therapy. Omentin and obestatin, two novel proteins were suggested to be associated with insulin resistance, type 2 diabetes and cardiovascular risk factors. Thus, we postulated that they may also have an association with diabetic nephropathy which is known to be an independent cardiovascular risk factor. In order to investigate such an association we compared serum omentin and obestatin levels in type 2 diabetic patients with normoalbuminuria (NA) and macroalbuminuria (MA). Materials and Methods: A total of 81 type 2 diabetic patients were separated into two groups according to their proteinuria status; patients with NA (n = 39) and patients with MA (n = 42). Two groups were compared in terms of serum omentin and obestatin levels. Results: While serum omentin levels did not differ among two groups (P = 0.407), serum obestatin levels were significantly higher in MA group (P = 0.001). Conclusion: The results of this study showed that higher serum levels of obestatin were associated with macro albuminuria suggesting that obestatin may have a role in underlying pathogenic mechanisms that leads to diabetic nephropathy
Open Access
Antioxidant and toxicological in-vivo and in-vitro examination of licorice extract
(2016-09-01) Bektay, MUHAMMED YUNUS; Uckaya, FATİH; Guler, E. M.; Bayindir, NİHAN; Kocyigit, ABDÜRRAHİM; Esrefoglu, MUKADDES; Topcu, GÜLAÇTI; BEKTAY, MUHAMMED YUNUS; UÇKAYA, FATİH; GÜLER, ERAY METİN; BAYINDIR, NİHAN; KOÇYİĞİT, ABDÜRRAHİM; EŞREFOĞLU, MUKADDES; TOPÇU, GÜLAÇTI
Open Access
Paraoxonase-1 Phenotype and Its Relationship with Mean Platelet Volume and Oxidative Stress in Coronary Artery Disease
(2015-09-01) SELEK, ŞAHBETTİN ; ÖZER, ÖMER FARUK ; GOKTEKİN, Omer ; KOÇYİĞİT, ABDÜRRAHİM; KALINBACOGLU, Ceren; ISLEK, Irem ; ISLEK, Tuğba; ARPACI, Beyza; Erol, Neval; MEYDAN, Sedat; GÜLER, ERAY METİN; SELEK, ŞAHABETTİN; ÖZER, ÖMER FARUK; KOÇYİĞİT, ABDÜRRAHİM; MEYDAN, SEDAT; GÜLER, ERAY METİN
Objective: Paraoxonase-1 (PON1) 192 QR polymorphism is believed to be an important protective factor for coronary artery disease (CAD); oxidative stress plays a key role in the development of atherosclerotic CAD. Mean platelet volume (MPV) is also central to the processes, including pathophysiology of CAD and endothelial dysfunction. Thus, we aimed to determine the PON1 phenotype, MPV, and oxidative stress parameters in patients with angiographically proven CAD and to compare them with those in healthy subjects. Methods: Fifty-five CAD patients were diagnosed according to the angiography results, and 37 healthy subjects were present in this study. Serum paraoxonase and arylesterase activities were spectrophotometrically measured. Phenotype distribution was evaluated by the salt-stimulated paraoxonase activity according to arylesterase activity. Oxidative stress markers were evaluated by measuring serum total oxidant status (TOS) and total antioxidant status (TAS) as well as oxidative stress index. Results: In this study, the ratio of salt-stimulated paraoxonase/ OSI levels (S-PON1/OSI) were lower in the CAD patients and the differences were statistically significant (p<0.05). Therefore, the ratio of salt-stimulated paraoxonase/MPV (S -PON1/MPV) and S- PON1/OSI level were significantly different in the CAD patients as compared with controls group (p<0.01). Conclusion: Our study has suggested that S-PON1/OSI and SPON1/ MPV may play a significant role in CAD. To the best of our knowledge, the present study is the first to study the relationship among PON1 phenotype, MPV, and OSI in CAD patients. Thus, lowering of the oxidative stress and the regulation of MPV strategies may be a promising approach for the treatment of CAD.
Open Access
Evaluation of periostin level for predicting severity and chronicity of childhood atopic dermatitis
(2018-11-01) ÖZÇEKER, DENİZ; YÜCEL, ESRA; SİPAHİ, SEVGİ; DİLEK, FATİH; ÖZKAYA, EMİN; GÜLER, ERAY METİN; GÜLER, NERMİN; TAMAY, ZEYNEP ÜLKER; ÖZKAYA, EMİN; GÜLER, ERAY METİN; KOÇYİĞİT, ABDÜRRAHİM
Open Access
The investigation of the relationships of demodex density with inflammatory response and oxidative stress in rosacea
(2018-11-01) Falay Gür, Tuğba; erdil, duygu; Erdemir, Aslı Vefa; GÜLER, ERAY METİN; KOÇYİĞİT, ABDÜRRAHİM; KOÇYİĞİT, ABDÜRRAHİM; GÜLER, ERAY METİN
The relationships of demodex density with systemic oxidative stress, inflammatory response, and clinical severity in rosacea are not clear. This study aimed to (a) analyze the levels of systemic oxidative stress, antioxidant capacity, inflammatory parameters, and matrix metalloproteinases (MMPs) in systemic circulation in patients with rosacea, (b) identify the relationship between mite density and both oxidative stress and inflammation, and (c) investigate the role of photoaging and sebum secretion in etiopathogenesis. Forty patients with rosacea and 40 age-, sex-, and skin phenotype-matched healthy volunteers were included in the study. Clinical disease severity of the patients was determined. Sebum levels were measured in both the groups, and photoaging was evaluated. Reflectance confocal microscopy was used to calculate demodex density. Serum total antioxidant capacity (TAC), total oxidant capacity (TOC), myeloperoxidase (MPO), MMP-1, MMP-9, arylesterase (ARES), interleukin-1β (IL-1β), paraoxonase-1 (PON-1), and tumor necrosis factor-α (TNF-α) levels were also analyzed. The patients with rosacea had significantly higher serum TOC and lower TAC levels (p<0.001). The serum ARES and PON-1 levels were significantly lower (p=0.045 and p<0.00.1, respectively); however, the serum levels of MMP-1, MMP-9, IL-1β and MPO were higher in the patient group. Demodex parameters were higher in the patient group compared to the control group. There was no significant correlation between the number of mites and disease severity. In addition, the number of mites was not correlated with the serum levels of TAC, TOC, OSI, MPO, MMP-1, MMP-9, ARES, PON-1, TNF-α, and IL-1β. However, sebum levels were directly proportional to the number of mites. Photoaging severity was similar between the patients and control subjects. The changing sebaceous microenvironment in rosacea leads to an increase in the number of demodex mites. However, increased demodex density does not alter disease severity, level of oxidative stress, or inflammation. Although none of the patients with rosacea had any underlying systemic disease, patients’ systemic oxidative stress and inflammation parameters were found high in systemic circulation. It is assumed that the patients with rosacea are more prone to systemic diseases.
Open Access
Plasma lipoxin a4 levels in childhood chronic spontaneous urticaria
(2018-01-01) DİLEK, FATİH; ÖZÇEKER, DENİZ; GÜLER, ERAY METİN; ÖZKAYA, EMİN; YAZICI, MEBRURE; TAMAY, ZEYNEP ÜLKER; KOÇYİĞİT, ABDURRAHİM; GÜLER, NERMİN; GÜLER, ERAY METİN; ÖZKAYA, EMİN; YAZICI, MEBRURE; KOÇYİĞİT, ABDÜRRAHİM
Dilek F, Özçeker D, Güler EM, Özkaya E, Yazıcı M, Tamay Z, Koçyiğit A, Güler N. Plasma lipoxin A4 levels in childhood chronic spontaneous urticaria. Turk J Pediatr 2018; 60: 527-534. Chronic spontaneous urticaria (CSU) is an idiopathic inflammatory disorder. Despite great research progress, the pathogenesis of the disease is still not fully understood. Lipoxins (LXs) are autacoid lipid metabolites that are the first discovered members of a new genus named called `specialized proresolving mediators`. In this study, we aimed to investigate the possible role of LXA4 in the pathogenesis of CSU. Forty-two children with CSU and 25 healthy children were enrolled in the study. The demographic and clinical features of patients were evaluated, autologous serum skin tests (ASSTs), and routine laboratory assessments were performed. Disease activity was determined using the urticaria activity score. An enzyme-linked immunosorbent assay was used to evaluate LXA4 plasma levels. The median value of plasma LXA4 was found to be 60.8 ng/ml (interquartile range, 48.1-71.8) in CSU patients and 137.4 ng/ml (121.4-150.8) in the control group. The difference between the groups was statistically significant (p < 0.001). Additionally, the median plasma LXA4 levels in the ASST-positive patients were significantly reduced compared to the ASST-negative ones (45.8 [36.7-67.6] versus 63.8 [58.3-78.9] ng/ml, respectively, p < 0.05). Our results showed that diminished LXA4 biosynthesis may be a critical part of CSU pathogenesis in children, especially in patients with an autoimmune component.
Open Access
Thymoquinone enhances the sensitivity of B16-F10 melanoma cell line to Gamma Knife radiosurgery
(2019-11-22T00:00:00Z) HATİBOĞLU, MUSTAFA AZİZ; KOÇYİĞİT, ABDÜRRAHİM; GÜLER, ERAY METİN; AKDUR, KERİME; Khan, İmran; NALLI, ARİFE; KARATAŞ, ERSİN; TÜZGEN, SAFFET; HATİBOĞLU, MUSTAFA AZİZ; KOÇYİĞİT, ABDÜRRAHİM; GÜLER, ERAY METİN
Open Access
Investigation of cytotoxic, genotoxic, and apoptotic effects of curcumin on glioma cells
(2019-03-01) SEYİTHANOĞLU, MEHMET HAKAN; ABDALLAH, ANAS; kitiş, serkan; GÜLER, ERAY METİN; DÜNDAR, TOLGA; GÜNDAĞ PAPAKER, MELİHA; SEYİTHANOĞLU, MEHMET HAKAN; KİTİŞ, SERKAN; GÜLER, ERAY METİN; KOÇYİĞİT, ABDÜRRAHİM; DÜNDAR, TOLGA TURAN; GUNDAG, MELİHA
Open Access
Plasma total thiol pool in children with asthma: Modulation during montelukast monotherapy
(2016-03-01) DILEK, Fatih; Ozkaya, EMİN; Kocyigit, ABDÜRRAHİM; Yazici, MEBRURE; Guler, ERAY METİN; DUNDAROZ, Mehmet Rusen; ÖZKAYA, EMİN; KOÇYİĞİT, ABDÜRRAHİM; YAZICI, MEBRURE; GÜLER, ERAY METİN
Background: Inflammation, which is a hallmark of asthma, is one of the main sources of oxidative stress in the human body. Thiols are powerful antioxidants that protect cells against the consequences of oxidative stress. We aimed to investigate whether asthma and montelukast monotherapy affect the total plasma thiol pool in children. Methods: A total of 60 children with asthma and 35 healthy controls participated in the study. Group I consisted of newly diagnosed asthmatics who did not have regular anti-asthmatic therapy previously. Group II consisted of patients who had been undertaking montelukast monotherapy regularly for at least 4 months. Plasma total antioxidant status (TAS) and plasma total thiol (PTT) were measured using spectrophotometric methods. Results: Bronchial asthma patients in both groups I and II had decreased median TAS levels compared with the control group (1.59 [interquartile range, 1.04–1.70] and 1.67 [1.50–1.75] vs. 2.98 [2.76–3.16] Trolox equiv./L, respectively; P <0.001). Group I had decreased PTT concentrations compared with the control group (0.18 [0.16–0.20] vs. 0.21 [0.19–0.22] mmol/L; P <0.001), and group II had similar PTT levels to the control group (0.20 [0.17–0.22] mmol/L; P >0.05). In addition, the median TAS and PTT levels for groups I and II were not statistically different (P >0.05). There was a positive correlation between TAS and PTT levels (rho = 0.38, P <0.05) in group I. Conclusion: In order to balance the oxidative stress, both TAS and PTT which are markers of the antioxidant system are reduced in children with asthma. Montelukast monotherapy can limit oxidative stress and thus restore PTT levels but not TAS levels in asthmatic children.
Open Access
Quercus pyrenaica Honeydew Honey With High Phenolic Contents Cause DNA Damage, Apoptosis, and Cell Death Through Generation of Reactive Oxygen Species in Gastric Adenocarcinoma Cells
(2019-09-01) KOÇYİĞİT, ABDÜRRAHİM; Aydogdu, Gokhan; BALKAN, EZGİ; GÜLER, Eray Metin; BULUT, HURİ; KÖKTAŞOĞLU, FATMANUR; Goeren, AHMET CEYHAN; Atayoglu, Ali Timucin; KOÇYİĞİT, ABDÜRRAHİM; BALKAN, EZGİ; YENİGÜN, VILDAN BETÜL; GÜLER, ERAY METİN; BULUT, HURI; KÖKTAŞOĞLU, FATMANUR; GÖREN, AHMET CEYHAN
Many studies have shown that honey with high phenolic contents prevents cancer formation. Furthermore, recent studies have demonstrated that honey can be used for the treatment of cancer as well as cancer prevention. Antineoplastic effects of honey are often associated with their antioxidant phenolic contents. However, very few studies have dealt with the association of phenolic contents of honeys in terms of antiproliferative effects. The aim of this study was, therefore, to elucidate the cytotoxic, genotoxic, apoptotic, and reactive oxygen species (ROS) generating effects of honey samples on the basis of their phenolic and flavonoid contents. Fourteen different honey varieties were collected from various parts of Turkey, and their characteristics regarding total phenols, flavonoids, and antioxidant contents were determined to test their effects on gastric cancer cells (AGS). For convenience, 2 honey varieties were selected, namely, Ida Mountains Quercus pyrenaica honeydew honey (QPHH-IM) having the highest phenolic and antioxidant content and Canakkale multifloral honey (MFH-C) with the lowest phenolic and antioxidant content. Levels of 11 different phenolic compounds in QPHH-IM and MFH-C samples were determined by LC-MS/MS. AGS cells were incubated with different concentrations of QPHH-IM and MFH-C for 24 hours, then the cell viability, DNA damage, apoptosis, and generation of ROS were determined. We found that QPHH-IM had more cytotoxic, genotoxic, and apoptotic effects than that of MFH-C. We think that these effects are probably related to pro-oxidant activities due to the high phenolic contents present. Therefore, further research on high-phenolic honey may contribute to the future development of cancer therapeutics.