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SELEK, ŞAHABETTİN

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ŞAHABETTİN
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SELEK
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Now showing 1 - 10 of 71
  • PublicationMetadata only
    Iron deficiency anemia and levels of oxidative stress induced by treatment modality
    (2013-06-01T00:00:00Z) Akarsu, Saadet; Demir, Hatice; Selek, ŞAHBETTİN; Oguzoncul, Ferdane; SELEK, ŞAHABETTİN
    Background The effects of iron deficiency anemia (IDA) and its treatment on plasma total antioxidant capacity (TAOC) were investigated. Methods Sixty patients with IDA and 20 healthy controls were divided into four subgroups: an oral (per os: PO) group (n = 20); an intramuscular (IM) group (n = 20); an intravenous (IV) group (n = 20); and the control group (n = 20). Blood samples were obtained from all patients before treatment, and at 24h, 7 days, 6 and 13 weeks after initiation of IDA therapy. Results TAOC in the IDA group was low when compared with the control group (P < 0.001). Although TAOC at 24h in the PO group was not different from the control group, the TAOC in the IM and IV groups was relatively lower (P < 0.001). The TAOC in the PO group at 7 days, and at 6 and 13 weeks was closest to the control group level. The mean TAOC in the IV group at 13 weeks was clearly lower relative to the PO and IM groups. Conclusions Oxidative stress was minimally induced with oral therapy, while IM and IV therapies induced higher levels of oxidative stress, in increasing order of intensity.
  • PublicationMetadata only
    Molecular cloning and characterization of NAD(+) dependent isocitrate dehydrogenase enzyme from Shewanella putrefaciens
    (2021-10-01T00:00:00Z) Fahri, Akbas; Metin, Demirel; Ahmet, Ozaydin; Sahabettin, ŞAHBETTİN; AKBAŞ, FAHRİ; DEMİREL, METİN; SELEK, ŞAHABETTİN
    Isocitrate dehydrogenase (IDH) is a fundamental enzyme for carbon metabolism in the Krebs cycle. This enzyme is required for oxidation-reduction reactions in both eukaryotic and prokaryotic cells and plays a critical role in their growth and pathogenesis. In this study, we cloned the gene encoding NAD(+) dependent isocitrate dehydrogenase from Shewanella putrefaciens. The expression of recombinant protein was induced with 0.5 mM of IPTG. His-tagged IDH overexpressed in E. coli was purified and characterized. The expressed IDH enzyme was purified in an active soluble form. The molecular weight of the enzyme was confirmed with Western blotting. High sequence homology was observed with IDH sequences of other Shewanella strains and remarkable sequence homology was found with other bacteria reported in the database.
  • PublicationOpen Access
    Diagnostic potential of Brucella melitensis Rev1 native Omp28 precursor in human brucellosis
    (2018-01-01) Koyuncu, Ismail; Kocyigit, ABDÜRRAHİM; Ozer, Ahmet; SELEK, Sahabettin; Kirmit, Adnan; Karsen, Hasan; KOÇYİĞİT, ABDÜRRAHİM; SELEK, ŞAHABETTİN
    Serologic tests for brucellosis aim to detect antibodies produced against membranous lipopolysaccharide of bacteria. Diagnostic use of this method is limited due to false positiveness. This study evaluates an alternative antigen to lipopolysaccharides (LPS), outer membrane 28-precursor-protein, of Brucella melitensis Rev1 for its diagnostic value. Omp28 precursor of B. melitensis Rev1 was cloned, expressed, and purified. 6-His and sumo epitope tags were used to tag the protein at N-termini. Omp28 gene was amplified based on the ORF sequence and cloned into a pETSUMO vector. The recombinant construct was propagated in Escherichia coli One Shot® Mach1™ cells then transformed into E. coli BL21(D3) cells for protein expression. The purified protein was studied in an indirect ELISA for diagnosis of brucellosis. Sera samples from 60 patients were screened by ELISA and the results were compared to Rose Bengal plate test. Recombinant antigen-based iELISA has given a successful outcome with the sensitivity, specificity, positive predictive value, and negative predictive value of 87.8%, 96.2%, 96.6%, and 78.78%, respectively. In conclusion, recombinant production and purification of the immunodominant Omp28 precursor protein has been achieved successfully in a one-step process with efficient yield and can be used for diagnosis of brucellosis in humans
  • PublicationMetadata only
    Gamma glutamyl transferase activity is Independently associated with oxidative stress rather than SYNTAX score
    (2015-01-01) UCAR, Hakan; GUR, Mustafa; GOZUKARA, Mehmet Yavuz; KALKAN, Gulhan Yuksel; BAYKAN, Ahmet Oytun; TURKOGLU, Caner; KAYPAKLI, Onur; SEKER, Taner; SEN, Omer; Selek, Sahbettin; CAYLI, Murat; SELEK, ŞAHABETTİN
    Background. Gamma glutamyl transferase (GGT) is involved in the pathophysiologic process of coronary atherosclerosis. GGT activity plays a role in the catabolism of glutathione which is known as one of the major antioxidants. However, there is a lack of research on direct examination of relevance between serum GGT activity with systemic oxidative stress. Objectives. We aimed to investigate the relationship between GGT activity with systemic oxidative stress markers and the extent and complexity of coronary artery disease (CAD) assessed with SYNTAX score in stable CAD. Methods. Measurements were obtained from 359 patients with stable CAD (Mean age = 57.7 +/- 10.1 years). The patients were divided into two groups according to the median GGT level (GGT median group > 22). Angiography was performed and SYNTAX score was calculated in all patients. Oxidative stress markers (total oxidant status [TOS], total antioxidant capacity [TAC] and oxidative stress index [OSI]) were measured in all patients. Results. While SYNTAX score and oxidative stress markers such as TOS and OSI have been increased, TAC was decreased in GGT > median group compared with GGT < median group (p < 0.05, for all). GGT activity was independently associated with diabetes (beta = 0.106, p = 0.015) and OSI (beta = 0.556, p < 0.001) in multiple linear regression analysis. However, the independent association between GGT activity and SYNTAX score was not found in present study (beta = 0.063, p = 0.238). Conclusion. In stable CAD, increased GGT activity within the normal range is associated with increased oxidative stress rather than increased extent and complexity of CAD.
  • PublicationMetadata only
    An evaluation of Neuropeptide Y status in subacute sclerosing panencephalitis patients
    (2013-01-01T00:00:00Z) Abuhandan, M.; Calik, M.; Almaz, V.; Taskin, A.; Cakmak, A.; Selek, ŞAHBETTİN; SELEK, ŞAHABETTİN
    Aim. This study aimed to evaluate the neuropeptide Y values of patients with subacute sclerosing panencephalitis.
  • PublicationOpen Access
    Oxidative Stress and Spontaneous Reperfusion of Infarct-Related Artery in Patients With ST-Segment Elevation Myocardial Infarction
    (2016-03-01) Borekci, Abdurrezzak; Gur, Mustafa; TURKOGLU, Caner; Selek, Sahbettin; BAYKAN, Ahmet Oytun; SEKER, Taner; HARBALIOGLU, Hazar; OZALTUN, Betuel; MAKCA, Ilyas; Aksoy, Nurten; GOZUKARA, Yavuz; CAYLI, Murat; SELEK, ŞAHABETTİN
    In the pathogenesis of atherosclerosis, oxidative stress plays a major role in plaque instability, rupture, and erosion, which subsequently leads to thrombus formation and causes total infarct-related artery (IRA) occlusion. We investigated the relationship between spontaneous reperfusion (SR) of IRA and oxidative stress in patients with anterior ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention. A total of 341 consecutive patients with anterior STEMI were prospectively included in the present study. Patients were divided into 2 groups according to their thrombolysis in myocardial infarction (TIMI) flow grade: SR group (66 patients, TIMI flow 3) and non-SR group (275 patients, TIMI flow 0-2). On multivariate logistic regression analysis, oxidative stress index ( = 0.868, 95% confidence interval [CI] = 0.806-0.934, P < .001), neutrophil to lymphocyte ratio, uric acid, mean platelet volume, Killip 2 to 4 class, and initial SYNTAX score were independently associated with SR. Oxidative stress as well as inflammation may play a pivotal role in the pathogenesis of SR in patients with STEMI.
  • PublicationMetadata only
    Serum paraoxonase enzyme activity and oxidative stress in obese subjects
    (2011-01-01T00:00:00Z) ASLAN, Mehmet; Horoz, Mehmet; Sabuncu, Tevfik; Celik, Hakim; Selek, Sahbettin; SELEK, ŞAHABETTİN
    Introduction Obesity is an important risk factor for atherosclerotic cardiovascular disease. Paraoxonase-1 (PON1) may play a significant role in the prevention of obesity-related accelerated atherosclerosis by hydrolyzing lipid peroxides in oxidized low-density lipoproteins.
  • PublicationMetadata only
    Protective effects of caffeic acid phenethyl ester and thymoquinone on toluene induced liver toxicity.
    (2019-05-01) Esrefoglu, MUKADDES; Bayındır, NİHAN; KURBETLI, N; Selek, S; Akbas, Tosunoglu; Meydan, SEDAT; OZTURK, OSMAN; Bulut, HURİ; Meral, I; MEYDAN, SEDAT; EŞREFOĞLU, MUKADDES; SELEK, ŞAHABETTİN; ÖZTÜRK, OSMAN; BAYINDIR, NİHAN; BULUT, HURI; MERAL, İSMAİL
  • PublicationOpen Access
    Could Vitamin K1 Deficiency be the Problem in Iron Deficiency and/or Anemia in Premenopausal Women?
    (2022-04-01T00:00:00Z) Karatoprak, Cumali; Şekerci, Abdusselam; Karaaslan, Tahsin; Olgaç, Atilla; Özer, Ömer Faruk; Selek, Şahabettin; Köktaşoğlu, Fatmanur; Ekinci, İskender; KARATOPRAK, CUMALİ; ŞEKERCİ, ABDÜSSELAM; ÖZER, ÖMER FARUK; SELEK, ŞAHABETTİN
    Objective: The etiology of iron deficiency anemia, which develops as a result of menstrual bleeding in the premenopausal period, is unknown. Vitamin K1 has an important role in the coagulation cascade and is not a well known vitamin. The aim of this study was to investigate whether or not Vitamin K1 had a role in anemia developing in the premenopausal period, for which no additional reason could be found. Methods: This study included a patient group of women aged 18-50 years, who had a regular menstrual cycle. Patients who were found to have iron deficiency, who were evaluated hematologically, gastrointestinally and gynecologically, and who did not have a pathology that would lead to iron deficiency were included in the study group.The control group comprised volunteers with regular menstrual cycles who had not been previously determined with iron deficiency. In the study, Vitamin K1, Hemogram, ferritin, iron, total iron binding capacity were examined. The Vitamin K1 level was measured by two different methods both using ELISA and liquid chromatography-mass spectrometry (LC-MS/MS) methods. In addition, a record was made for all participants including demographic characteristics, lifestyle habits, and number of menstruating days. The obtained data were then compared between the groups. Results: A total of 88 voluntary participants were included in the study as 45 patients with iron deficiency anemia (IDA) and a control group of 43 subjects. The age, body mass index, partial thromboplastin, International normalized ratio, active partial thromboplastin time, folic acid, and Vitamin B12 values were similar in both groups. In both methods, no significant difference was determined between the groups in respect of the Vitamin K1 level (p=0.9 in ELISA method and p=0.3 in LC-MS/MS method). The number of menstruation days was determined to be significantly higher in the anemic group than in the control group (p=0.002). Conclusion: From the results of this study, it was considered that IDA developed in premenopausal women with a longer period of menstrual bleeding. However, Vitamin K1 deficiency was not considered to be one of the underlying reasons for longer menstrual bleeding.
  • PublicationMetadata only
    Oxidative stress index may play a key role in patients with pemphigus vulgaris
    (2013-04-01T00:00:00Z) Yesilova, Y.; Ucmak, D.; Selek, ŞAHBETTİN; Dertlioglu, S. B.; Sula, B.; Bozkus, F.; Turan, E.; SELEK, ŞAHABETTİN
    Background Increased reactive oxygen species (ROS) and lipid peroxidation are seen in many dermatologic disorders, including atopic dermatitis, psoriasis, vitiligo, acne vulgaris, pemphigus vulgaris (PV), lichen planus and alopecia areata. In PV, the increased production of ROS from activated neutrophils reduces the concentrations of antioxidant vitamins and enzymes. Objective The present study aims to determine the oxidative stress index (OSI) by studying serum total oxidant capacity (TOC), lipid hydroperoxide (LOOH) and total antioxidant capacity (TAC) in PV patients. Methods The study included 27 PV patients and a control group consisting of 24 healthy volunteers. Serum TOC, LOOH and TAC levels were examined and OSI was measured in the PV patients and the control group. Results TOC (P=0.001) and LOOH (P=0.001) levels as well as OSI (P=0.001) were found higher in the PV patients, relative to the control group. Serum TAS (P=0.221) did not differ between groups. Serum TOC, LOOH and TAC levels and OSI in PV patients with mucosal involvement were not different than those in mucocutaneous PV patients. Conclusion Serum TOC and LOOH levels and OSI were higher in the PV patients, in comparison with the control group. Serum TAC level was not different.