Person: OKTAY, NİHAL ŞEHKAR
Loading...
Email Address
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
OKTAY
First Name
NİHAL ŞEHKAR
Name
18 results
Search Results
Now showing 1 - 10 of 18
Publication Open Access Comparison of the protective effect of alpha lipoic acid and quercetin in methotrexate- induced lung damage(2023-03-01) AK, ESİN; OKTAY, NİHAL ŞEHKAR; AK E., MUHAN A., ÇALIŞKAN Ş., OKTAY N. Ş.Objective: The aim of this experiment is to investigate and compare the effects of alpha lipoic acid (ALA) and quercetin (QUE) on methotrexate (MTX)-induced lung injury in rats. Method: Wistar Albino rats were distributed into control, MTX, MTX+ALA and MTX+QUE groups with each consisting of 6 rats. Except control group, MTX administrated to rats as a single dose (20 mg/kg) intraperitoneally (i.p.) on the first day. Saline (0.1 cc/100 gr/day, i.p.) was injected to rats in control and MTX groups for 5 days. In MTX+ALA and MTX+QUE groups, rats had injections of ALA (50 mg/kg/day, i.p.) and QUE (50 mg/kg/day, i.p.) for 5 days. After sacrification on day 6, lung tissues were excised out for histopathologic and biochemical investigation. Results: MTX group showed massive hemorrhage with edema in the interstitium, significant inflammatory cell infiltration, and severe alveolar destruction and vascular congestion. Additionally, significant increases in oxidative stress markers as malondialdehyde and sialic acid and significant decreases in antioxidants as glutathione, superoxide dismutase and catalase were detected at the tissue level in MTX group (p<0.0001, p<0.0001, p<0.0001, p=0.03 and p<0.0001, respectively). Both ALA and QUE treatment led to a prominent improvement in morphologic damage. Moreover, ALA and QUE resulted in the reversal of the alterations seen in the tissue oxidative damage markers and antioxidant activities as well. We could not reveal a significant difference between MTX+ALA and MTX+QUE group in terms of morphologic damage and biochemical markers of oxidative injury (p>0.05). Conclusion: Our study showed the similar protective effect of ALA and QUE in MTX induced lung damage. Further studies are warranted to verify the results of our outcome.Publication Metadata only The effect of a single application of different fluoride varnishes on enamel subsurface lesions in vitro(2022-04-01) ŞEN YAVUZ, BETÜL; YILMAZ, MÜESSER AHU; OKTAY, NİHAL ŞEHKAR; KARGÜL, BETÜL; Yildiz P. K., ŞEN YAVUZ B., YILMAZ M. A., OKTAY N. Ş., KARGÜL B.This in vitro study aimed to evaluate the therapeutic effect of different fluoride ion (F) varnish formulations for controlling the carious development of enamel subsurface lesions and the F release into artificial saliva for 2 hr, 24 hr, 48 hr, and 7 days. Artificial enamel carious lesions were created and divided into 6 groups (5 varnish groups and a control group). Varnishes were applied to enamel specimens and then the specimens were incubated in artificial saliva, with the artificial saliva replenished daily. Varnish was removed and lesions were remineralized in artificial saliva for 24 hr. Surface microhardness was measured three times: (i) initially, (ii) after creating the artificial enamel lesions, and (iii) after applying the varnishes. The F release was analyzed after 2 hr, 24 hr, 48 hr, and 7 days of exposure using an ion-selective electrode. Data were analyzed using a One-way Analysis of Variance with the Tukey-Kramer Multiple Comparisons test and the Kruskal-Wallis test with the Dunns Multiple Comparisons test. The highest percentage surface microhardness recovery was found for the treatment with the MI Varnish. According to the percentage surface microhardness recovery results, a statistically significant difference was found between the varnishes and the control group (p < 0.05 and < 0.001). All varnishes released measurable levels of fluoride ions. However, the release of F was the highest in the MI Varnish group (p < 0.01). Duraphat, Enamel Pro Varnish, and MI Varnish released the most F into artificial saliva. Calcium phosphate-based F varnishes improve the capacity of the enamel surface re -hardening. CPP containing F varnish had the highest release of F as compared to the other F releasing varnishes. Further in vivo investigations are also required to prove the clinical applications of the different ingredients containing varnishes.Publication Metadata only Edaravone ameliorates the adverse effects of valproic acid toxicity in small intestine(SAGE PUBLICATIONS LTD, 2015) YARAT, AYŞEN; Oktay, S.; Alev, B.; Tunali, S.; Emekli-Alturfan, E.; Tunali-Akbay, T.; Koc-Ozturk, L.; Yanardag, R.; Yarat, A.Valproic acid (VPA) is a drug used for the treatment of epilepsy, bipolar psychiatric disorders, and migraine. Previous studies have reported an increased generation of reactive oxygen species and oxidative stress in the toxic mechanism of VPA. Edaravone, a free radical scavenger for clinical use, can quench free radical reaction by trapping a variety of free radical species. In this study, effect of edaravone on some small intestine biochemical parameters in VPA-induced toxicity was investigated. Thirty seven Sprague Dawley female rats were randomly divided into four groups. The groups include control group, edaravone (30 mg(-1) kg(-1) day(-1)) given group, VPA (0.5 g(-1) kg(-1) day(-1)) given group, VPA + edaravone (in same dose) given group. Edaravone and VPA were given intraperitoneally for 7 days. Biochemical parameters such as malondialdehyde, as an index of lipid peroxidation(LPO), sialic acid (SA), glutathione levels and glutathione peroxidase, glutathione-S-transferase, superoxide dismutase, catalase, myeloperoxidase, alkaline phosphatase (ALP), and tissue factor (TF) activities were determined in small intestine samples by colorimetric methods. Decreased small intestine antioxidant enzyme activities, increased LPO and SA levels, and increased activities of ALP and TF were detected in the VPA group. Based on our results edaravone may be suggested to reverse the oxidative stress and inflammation due to VPA-induced small intestine toxicity.Publication Open Access The effects of aging on the functional and structural properties of the rat basilar artery(2014-06) OKTAY, NİHAL ŞEHKAR; Tümer, Nihal; Toklu, Hale Z.; Muller-Delp, Judy M.; Oktay, Şehkar; Ghosh, Payal; Strang, Kevin; Delp, Michael D.; Scarpace, Philip J.Publication Open Access Investigation of the Effects of Edaravone on Valproic Acid Induced Tissue Damage in Pancreas(MARMARA UNIV, FAC PHARMACY, 2017-06-20) YARAT, AYŞEN; Oktay, Sehkar; Alev-Tuzuner, Burcin; Tunali, Sevim; Ak, Esin; Emekli-Alturfan, Ebru; Tunali-Akbay, Tugba; Koc-Ozturk, Leyla; Cetinel, Sule; Yanardag, Refiye; Yarat, AysenValproic acid (VPA), an effective antiepileptic and anticonvulsant drug, has some toxic side effects due to causing elevated oxidant production. The aim of this study is to investigate the effects of edaravone, a potent free radical scavenger on VPA induced toxicity and tissue damage by biochemical and histological examinations on pancreas. Female Sprague Dawley rats were divided into four groups as follows; control, edaravone, VPA, VPA+edaravon. VPA and edaravone were injected intraperitonally for seven days. Total protein, lipid peroxidation (LPO), sialic acid (SA) and glutathione (GSH) levels and alkaline phosphatase (ALP), tissue factor (TF), superoxide dismutase (SOD), glutathione-S-transferase GST), catalase (CAT), glutathione peroxidase (GPx) and myeloperoxidase (MPO) activities were determined in pancreas homogenates. In VPA given group, LPO and SA levels, and ALP, TF, MPO activities significantly increased and GST, CAT, GPx activities significantly decreased compared to control group. A marked morphological damage was detected in the VPA group. Ameliorative effects of edaravone were observed in SA, TF, CAT, GPx parameters and histological examination in the VPA group. Therefore, edaravone may be effective in moderation and/or reduction of toxic effects of VPA on pancreas.Publication Open Access FUTBOLCULARDA SLC6A4 PROMOTÖR POLİMORFİZMİNİN DAĞILIMI(2021-11-26) TACAL ASLAN, BESTE; Başak Funda EKEN;Tolga POLAT;Canan SERCAN DOĞAN;Beste Tacal ASLAN;Şehkar OKTAY;Korkut ULUCANİnsan psikolojisini etkileyen ve en önemli bir biyobelirteç olan serotonin, sporcunun atletik performansını da olumsuz yönde etkileyebilmektedir. Çalışmamızın amacı, sağlıklı profesyonel futbolcularda anksiyete ile bağlantılı SLC6A4 geni promotör bölgesinde “S” ve “L” allel dağılımının incelenmesidir. Çalışmamıza aktif olarak haftada en az 4 gün antrenman programı uygulayan 15-29 yaş arası 19 profesyonel futbolcu ve herhangi bir egzersiz programı uygulamayan (kontrol grubu) 45 birey katıldı. Gerekli etik kurul izinleri alındıktan sonra çalışma protokolunun sonuç ve çıktılarını anlatan onam formları katılımcılara imzalatıldı. Çalışmamıza katılan bireylerden daha sonra ağız içi epitel hücreleri alınarak DNA izolasyonu gerçekleştirildi. Tüm polimorfizmlerin genotiplemesi, polimeraz zincir reaksiyonu (PZR) metodu kullanılarak belirlendi. Çalışmamıza katılan futbolcularda SLC6A4 geninin LL, LS, SS genotiplerinin sayı ve yüzdeleri sırasıyla 11(%57,8), 4(%21,1), 4(%21,1) olarak belirlenmiştir. Çalışma kohortumuzda L alleli 26 (%68,4), S alleli ise 12 (%31,6) oranında gözlemlenmiştir. Çalışma grubumuzda SLC6A4 geninin promotör bölgesi incelendiğinde, LL genotipi baskın olarak bulunurken, L alleli de S alleline göre daha yüksek oranda bulunmuştur. Kontrol grubunda ise aynı genotip sayı ve yüzdeleri sırası ile 12 (%26,7), 24 (%53,3) ve 9 (%20) olarak belirlenmiştir. Kontrol grubundaki allelik dağılımı ise L alleli 48(%53,3), S alleli 42 (%46,7) olarak gözlenmiştir. Sporcu grubu ile kontrol grubu arasında genotip dağılımlarında (p=0,0001) bulunurken, allelik dağılımlarında (p=0,0425) bulunarak her iki grup arasında da istatiksel açıdan anlamlı farklılık saptanmıştır. Sonuç olarak çalışmamızda SLC6A4 promotör polimorfizmlerinin belirlenmesinin, sporcularda oluşan anksiyete ve bilişsel kaygı düzeyinin erken dönemde önlenmesine yardımcı olabileceği sonucuna varılmıştır.Publication Metadata only Is sialic acid a promising marker for periodontal diseases?(WOLTERS KLUWER MEDKNOW PUBLICATIONS, 2020) KURU, LEYLA; Oktay, S.; Bal, O. Ozoner; Kuru, L.; Yarat, A.; Noyan, U.Objective: Periodontal diseases are inflammatory chronic infections. Sialic acid (SA) is an acute phase reactant by itself. The aim of this study is to investigate the relationship between salivary and serum SA levels and clinical parameters in different forms of periodontal diseases. Subject and Methods: Systemically healthy subjects were included in the study; patients with chronic gingivitis (CG) (n = 10), chronic periodontitis (CP) (n = 10), and aggressive periodontitis (AgP) (n = 10), and ten volunteers with healthy periodontium as the control group. Total SA levels were determined by Warren's thiobarbituric acid method in whole saliva, parotis saliva, and serum samples of subjects before and 3 months after nonsurgical periodontal treatment. Full mouth clinical parameters including plaque index, gingival index, probing depth, and bleeding on probing were also recorded. Results: Before treatment, in both periodontitis groups salivary and serum SA levels were higher than those of controls (P = 0.001). Both salivary and serum SA levels decreased significantly in the patient groups after treatment (P < 0.001). Multiple comparisons of baseline clinical parameters in all groups revealed significant differences (P = 0.001) and these parameters decreased significantly on the 90th day (P < 0.01). There were positive correlations between SA levels and periodontal indices of the CG, CP, and AgP groups (P < 0.05). Conclusion: Our results suggest that SA level in both saliva and serum may be a potentially useful marker to determine inflammatory changes and investigate different forms of periodontal diseases.Publication Metadata only Effects of altered thyroid states on oxidative stress parameters in rats(Walter de Gruyter GmbH, 2017) OKTAY, NİHAL ŞEHKAR; Oktay S., Uslu L., Emekli N.Thyroid hormones are effective on oxidant-antioxidant balance by leading basal metabolic rate. In this study, the effects of altered thyroid states on low density lipoprotein (LDL) oxidation and oxidative stress parameters were investigated in an experimental animal model. Thirty female Wistar Albino rats were equally divided into 3 groups as follows: control group; hypothyroid group (methimazole (75 mg/100 g was added to diet); hyperthyroid group [L-thyroxine (0.4 mg/100 g was added to diet)]. Oxidized LDL (ox-LDL) levels, thyroid, and lipid parameters were determined in serum. Also lipid peroxidation (LPO), sialic acid (SA) and glutathione levels (GSH), as well as superoxide dismutase (SOD) and catalase (CAT) activities were determined in tissue samples. A significant increase in lipid parameters was observed in hypothyroid group, whereas these parameters were decreased in hyperthyroid group compared to control group. For ox-LDL levels, a significant increase was observed both in hypothyroid and hyperthyroid groups. In brain, liver and kidney tissues, LPO and SA levels were increased, whereas GSH levels were decreased both in hypothyroid and hyperthyroid groups. The SOD and CAT activities were significantly decreased in hypothyroid group, however, they were increased in hyperthyroid group compared to control group. Both hypothyroid and hyperthyroid conditions modify the oxidant-antioxidant state in serum and tissues. Increased SOD and CAT activities in hyperthyroid group suggest that elevated thyroid hormones can reduce oxidative stress by maintaining antioxidant defense and they might have a protective effect on some tissues against oxidants. © 2017 Walter de Gruyter GmbH, Berlin/Boston.Publication Open Access Edaravone Ameliorates Valproate-Induced Gingival Toxicity by Reducing Oxidative-Stress, Inflammation and Tissue Damage(MARMARA UNIV, FAC MEDICINE, 2016-05-10) YARAT, AYŞEN; Oktay, Sehkar; Alev, Burcin; Koc Ozturk, Leyla; Tunali, Sevim; Demirel, Sezin; Emekli Alturfan, Ebru; Tunali-Akbay, Tugba; Akyuz, Serap; Yanardag, Refiye; Yarat, AysenValproic acid (2-n-propylpentanoic acid, VPA), the most widely used antiepileptic drug, has potential adverse effects and it can disrupt the oxidant and antioxidant balance. Edaravone (3-methyl-1-phenyl-2-pyrazoline-5-one, EDA) is a potent free radical scavenger. In this study, the effect of EDA on gingiva in VPA induced toxicity was investigated. Female Sprague Dawley rats were randomly divided into four groups: control group, EDA (30 mg/kg/day) given group, VPA (0.5 g/kg/day) given group, and VPA+EDA (in same dose and time) given group. EDA and VPA were given intraperitoneally for seven days. Total protein, lipid peroxidation (LPO), sialic acid (SA) and reduced glutathione (GSH) levels and catalase (CAT), glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), myeloperoxidase (MPO), alkaline phosphatase (ALP), acid phosphatase (ACP), sodium potassium ATPase (Na+/K+-ATPase) and tissue factor (TF) activities were determined in gingiva homogenates. The VPA-induced increases were statistically significant for MPO (p<0.01), ACP (p<0.01), Na+/K+-ATPase (p<0.05) and TF (p<0.01) activities, but not for LPO level and ALP activities. EDA treatment markedly blunted all such elevated anomalies. Conclusively, VPA induced oxidative and inflammatory gingival tissue damage, reactions that were appreciably reversed by concurrent administration of EDA.Publication Metadata only Melatonin improves hyperglycemia induced damages in rat brain(WILEY, 2018) YARAT, AYŞEN; Gurel-Gokmen, Begum; Ipekci, Hazal; Oktay, Sehkar; Alev, Burcin; Ustundag, Unsal Veli; Ak, Esin; Akakin, Dilek; Sener, Goksel; Emekli-Alturfan, Ebru; Yarat, Aysen; Tunali-Akbay, TugbaBackground Diabetes mellitus is an endocrine disorder which is characterized by the development of resistance to the cellular activity of insulin or inadequate insulin production. It leads to hyperglycemia, prolonged inflammation, and oxidative stress. Oxidative stress is assumed to play an important role in the development of diabetic complications. Melatonin is the hormone that interacts with insulin in diabetes. Therefore, in this study, the effects of melatonin treatment with or without insulin were examined in diabetic rat brain. Methods Results Rats were divided into five groups as control, diabetes, diabetes + insulin, diabetes + melatonin, and diabetes + melatonin + insulin. Experimental diabetes was induced by streptozotocin (60 mg/kg, i.p.). Twelve weeks after diabetes induction, rats were decapitated. Malondialdehyde, glutathione, sialic acid and nitric oxide levels, superoxide dismutase, catalase, glutathione-S-transferase, myeloperoxidase, and tissue factor activities were determined in brain tissue. Melatonin alone showed its antioxidant effect by increasing brain glutathione level, superoxide dismutase, catalase, and glutathione-S-transferase activities and decreasing malondialdehyde level in experimental diabetes. Although insulin did not have a significant effect on glutathione and glutathione-S-transferase, its effects on lipid peroxidation, superoxide dismutase, and catalase were similar to melatonin; insulin also decreased myolopeoxidase activity and increased tissue factor activity. Combined melatonin and insulin treatment mimicked the effects of insulin. Conclusion Addition of melatonin to the insulin treatment did not change the effects of insulin, but the detailed role of melatonin alone in the treatment of diabetes merits further experimental and clinical investigation.