Person: MEYDAN, SEDAT
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Publication Open Access Could the PON1 phenotype play a key role in insulin resistance?(2022-06-01T00:00:00Z) Sarikaya, Ufuk; Meydan, Sedat; Selek, Şahabettin; Sarikaya, Alime; Demirel, Metin; Gül, Ayşe Zehra; Yildiz, Tuğçe; SARIKAYA, UFUK; MEYDAN, SEDAT; SELEK, ŞAHABETTİN; DEMİREL, METİN; GÜL, AYŞE ZEHRA; YILDIZ, TUĞÇEAim/objectivesRecent studies have shown that Paraoxonase (PON1) enzyme plays a possible role in insulin synthesis by stimulating insulin release from β-cells of the pancreas as well as its anti-atherosclerotic property. In our study, we revealed the relationship between phenotypes of the PON1 enzyme and insulin resistance (IR) and impaired fasting glucose (IFG).Materials and methodsA cohort of 71 IR, 63 IFG, and 68 healthy individuals was examined in this study. The phenotypic distribution was demonstrated by studying PON1 enzyme’s Paraoxonase (POase) and Arylesterase (AREase) activity with automated measurement kits.ResultsBy measuring the ratio of POase activity to AREase activity, 3 different phenotypes (QQ (Risky or Bad Phenotype), QR (Notre Phenotype), and RR (Good Phenotype)) were discovered. The results showed that IR and IFG individuals had riskier phenotypes compared to the control group. In addition, individuals with bad phenotypes were found to be 1.85 and 2.16 times more likely to get IR and IFG, respectively. Both groups were found to be four times more likely to be affected by the bad phenotype (odds ratio: 3.69 and 4.47 respectively).ConclusionIn this present study, the relationship between PON1 enzyme phenotypes and IR was evaluated for the first time in this field. Decreased PON1 activity and poor phenotype may also increase the development of hyperglycemia or diabetes mellitus (DM) due to IR and IFG. It may also predispose to diseases such as atherosclerosis. Therefore, we think that further investigations to explain the possible mechanisms underlying the relationship between PON1 phenotypes, IR and IFG will be useful in the early diagnosis and prevention ofprediabetes.Publication 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 METİNObjective: 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.Publication Open Access Assessment of Auditory Pathways Using Diffusion Tensor Imaging in Patients with Neurofibromatosis Type 1(2018-04-01) MEYDAN, SEDAT; Aydin, Sinem; OTCU, HAFİZE; KİTİŞ, SERKAN; ALKAN, ALPAY; MEYDAN, SEDAT; KİTİŞ, SERKAN; ALKAN, ALPAYThe aim of our study was to determine whether the diffusion properties of the auditory pathways alter between patients with Neurofibromatosis type 1 (NF1) and the healthy subjects. DTI can well demonstrate FA and ADC changes in auditory tracts and it may be a guide to identify the candidates for hearing loss among NF1 children.Publication Open Access Protective Effects of Curcumin on Cadmium-Induced Renal Injury in Young and Aged Rats(2016-12-01) Kumas, MELTEM; Esrefoglu, MUKADDES; Bayindir, NİHAN; Iraz, Meryem; Ayhan, Siddika; Meydan, SEDAT; KUMAŞ, MELTEM; EŞREFOĞLU, MUKADDES; BAYINDIR, NİHAN; MEYDAN, SEDATObjective: We aimed to investigate the protective effects of curcumin (Cr) against cadmium (Cd) toxicity on the kidneys of both young and aged rats. Methods: Forty-eight young and aged female Spraque–Dawley rats were divided into control, Cd, Cr, and Cd+Cr groups. We investigated kidney damage using a histopathological scoring system and measured total antioxidant status (TAS) and total oxidant status (TOS) and interleukin-6 (IL-6), procalcitonin (PCT), and C-reactive protein (CRP) levels. Results: Kidney tissues of Cd groups showed acute histopathological alterations. Cr improved Cd-induced histopathological changes (p<0.05). The highest mean TAS was recorded in both the Cr groups. The highest mean TOS was recorded only in the aged Cd group. Cr decreased IL-6 levels in both the Cd+Cr groups (p<0.05). PCT levels in the Cd groups were higher than those in the control groups. Significance was detected only between the young Cd and control groups (p<0.05). PCT levels were reduced in both the Cd+Cr groups (p<0.05). CRP levels in the aged Cd group were higher than those in the other groups (p<0.05). Cr reduced CRP levels only in the aged Cd+Cr group (p<0.05). Conclusion: Our results suggest that Cr prevents Cd-induced renal oxidative damage in both young and aged rats.Publication Open Access Effect of Camellia sinensis, Hypericum perforatum and Urtica dioica on kidney and liver injury induced by carbon tetrachloride in rats.(2019-06-30) Demirel, METİN; Meydan, SEDAT; Caglar, HG; Koktasoglu, F; Selek, ŞAHBETTİN; Sarikaya, A; SELEK, ŞAHABETTİN; KÖKTAŞOĞLU, FATMANUR; DEMİREL, METİN; MEYDAN, SEDAT