Nihayet Bayraktar
İnönü University
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Publication
Featured researches published by Nihayet Bayraktar.
Anesthesia & Analgesia | 2004
Semra Demirbilek; M. Özcan Ersoy; Savaş Demirbilek; Abdurrahman Karaman; Necla G rb z; Nihayet Bayraktar; Mehmet Refik Bayraktar
We investigated the influence of small- and large-dose capsaicin in modulating systemic inflammatory responses during different stages of sepsis in rats. Rats were divided into six groups: group C, control; group S, sepsis; group CLC, small dose of capsaicin (1 mg/kg subcutaneously); group SLC, small dose of capsaicin plus sepsis; group CHC, large dose of capsaicin (150 mg/kg subcutaneously); group SHC, large dose of capsaicin plus sepsis. Rats were made septic by cecal ligation and puncture (CLP). Each group was subdivided into two subgroups. The animals were killed at 9 or 18 h after CLP. Plasma concentrations of calcitonin gene-related peptide (CGRP), tumor necrosis factor (TNF)-&agr;, interleukin (IL)-6, IL-10, and total nitrite/nitrate (NOx) were measured. Superoxide dismutase and malondialdehyde (MDA) were determined in liver, lung, and heart tissues. CGRP was increased in groups S, CLC, and SLC when compared with the other groups. In the SLC group, plasma concentrations of TNF-&agr;, IL-6, NOx, and tissue MDA levels were reduced and IL-10 level was increased when compared with groups S and SHC 18 h after CLP (P < 0.05). Small-dose capsaicin treatment increased antiinflammatory IL-10 levels and attenuated the increases in proinflammatory cytokines, NOx, and tissue MDA in septic rats.
Mediators of Inflammation | 2005
Irfan Kuku; Mehmet Refik Bayraktar; Emin Kaya; Mehmet Ali Erkurt; Nihayet Bayraktar; Kerim Cikim; Ismet Aydogdu
Multiple myeloma (MM) is a malignant disease characterized by the clonal proliferation of plasma cells within the bone marrow. Several cytokines have been demonstrated to be involved in the control of growth, progression, and dissemination of MM. We determined serum levels of interleukin-1β (IL-1β), soluble interleukin-2 receptor (sIL-2R), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) in 14 newly diagnosed MM patients. The median age of the patients was 63.4 ± 10.8 years and all of the patients were stage III (classified according to the Durie-Salmon classification). The same parameters were measured in 15 healthy controls. In addition, we also examined the effects of vincristine-adriamycin-dexamethasone (VAD) therapy on the same parameters and mediators as well as the relationship among the parameters in the same patient groups. The serum concentrations of TNF-α, IL-1β, sIL-2R, IL-6, IL-8, and CRP (18.6 ± 3.7 pg/mL, 10.1 ± 2.8 pg/mL, 730 ± 220 U/mL, 11.4 ± 3.3 pg/mL, 23.9 ± 8.3 pg/mL, and 49.9 ± 19.5 mg/dL, resp) were significantly higher in newly diagnosed MM patients than in healthy controls (P < .0001). All of the parameters were found to be significantly reduced after chemotherapy. In conclusion, we found that after the VAD therapy, the level of these cytokines which are thought to play an important role in the pathogenesis of MM was significantly suppressed. This is the first study demonstrating strong impact of VAD treatment on circulating mediators of sIL-2R and IL-8 levels parameters.
Journal of International Medical Research | 2005
Emin Kaya; Lezzan Keskin; Ismet Aydogdu; Irfan Kuku; Nihayet Bayraktar; Ma Erkut
This study investigated changing levels of serum oxidant/antioxidant with chemotherapy and their relation to treatment in 34 Hodgkins lymphoma patients. The patient population consisted of 19 males and 15 females. Mean age was 30.41 ± 12.08 years. All patients received the adriamycin, bleomycin, vincristine and dexamethasone (ABVD) treatment protocol. Blood samples were taken before treatment, and on days 1 and 7 during treatment for measurement of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), malondialdehyde (MDA), nitric oxide (NO) and enzyme activities. After ABVD treatment, mean free radical levels were increased and antioxidant levels were significantly decreased in the serum. ABVD treatment results in an increase of free radical levels and a decrease of antioxidant levels in the serum of patients with Hodgkins lymphoma.
European Surgical Research | 2006
S. Demirbilek; E. Sizanli; N. Karadag; A. Karaman; Nihayet Bayraktar; E. Turkmen; M.O. Ersoy
Purpose: We aimed to investigate the effects of methylene blue (MB) on NO production, myeloperoxidase (MPO) activity, antioxidant status and lipid peroxidation in lung injury during different stages of sepsis in rats. Material and Methods: Rats were randomly divided into 4 groups (n = 20): group C, sham operated; group CMB, sham operated and receiving MB (25 mg/kg, i.p.); group S, sepsis; group SMB, sepsis and receiving MB (25 mg/kg, i.p.). Sepsis was induced by cecal ligation and puncture (CLP). The MB dose was administered after CLP. Each group was subdivided into two subgroups (n = 10) which were sacrificed at 9 or 18 h after the surgical procedure. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and MPO activity, total nitrite/nitrate and malondialdehyde (MDA) in the lung tissue were measured. Lung injury was graded from 1 (injury to 25% of the field) to 4 (diffuse injury) by the pathologist. Results: In group SMB, while SOD and CAT increased in both early and late sepsis periods, GSH-PX increased significantly only in the early sepsis period when compared with group S. Increase in lung MPO activity after CLP-induced sepsis was prevented by MB administration. MB significantly decreased to nitrite/nitrate and MDA levels both in early and late sepsis periods when compared with group S (p < 0.05). Group S showed a marked increase in neutrophil infiltration into the interstitial space and thickening of the alveolar septa, whereas the alveolar damage score was lower in the SMB group (p < 0.05). Conclusion: MB reduced the MPO activity and lipid peroxidation by both decreasing oxidative stress and NO overproduction in the lungs, which resulted in the attenuation of lung injury after CLP-induced sepsis in rats.
Journal of Clinical Laboratory Analysis | 2010
Nihayet Bayraktar; Süleyman Kılıç; Mehmet Refik Bayraktar; Nurten Aksoy
It is well known that antioxidants and reactive oxygen species play an important role in carcinogenesis. In this sudy, we attempted to evaluate antioxidant enzyme activities and lipid peroxidation levels in cancerous bladder tissue and to determine their relationship with bacterial infection. Bacterial culture was made from all urine samples using Blood and Eosin Methylene Blue agars for checking the presence of bacterial infections. We measured thiobarbituric acid reactive substances (TBARs) and activities of xanthine oxidase (XO), superoxide dismutase (SOD), glutathione peroxidase (GSH‐PX), and catalase (CAT) in cancerous tissues of 25 bladder cancer patients, in noncancerous adjacent bladder tissues of 13 out of these 25 patients, and in control bladder tissues of 15 patients with a non‐neoplastic genitourinary disease. TBARs levels increased and XO, SOD, GSH‐PX, and CAT activities decreased significantly in cancerous bladder tissues. TBARS, XO, and SOD levels were not significantly different between noncancerous adjacent tissue and control bladder tissue. Statistically significantly lower GSH‐PX and higher CAT activities were observed in noncancerous adjacent bladder tissue compared with cancerous tissue. GSH‐PX level of tumor tissue was correlated significantly with tumor grade (r=−0.425, P=0.034). Results suggested that pathway activity of free radicals were accelerated in the cancerous human bladder tissues via increased TBARs levels and decreased enzyme activities of XO, SOD, GSH‐PX, and CAT, which implicated a severe exposure of cancerous tissues to oxidative stress. J. Clin. Lab. Anal. 24:25–30, 2010.
Medical Principles and Practice | 2008
Mehmet Ali Erkurt; Ismet Aydogdu; Mustafa Dikilitas; Irfan Kuku; Emin Kaya; Nihayet Bayraktar; Onur Ozhan; Ibrahim Ozkan; Ahmet Sönmez
Objective: The aim of the study was to evaluate the role of vitamin B12 in patients with pernicious anemia. Materials and Methods: This study was conducted prospectively at the Turgut Özal Medical Center, Department of Hematology, between April and November 2002. Absolute numbers and ratio of the surface antigens of T and B lymphocyte subgroups, CD4/CD8 ratio were calculated in order to evaluate changes in leukocyte and lymphocyte numbers; natural killer (NK) cell count, serum C3, C4, and levels of immunoglobulins G, A, and M were also measured to evaluate vitamin B12 effect on immunity. Values obtained before treatment with cyanocobalamin were compared with those found during peak reticulocyte count. Results: In vitamin B12-deficient patients, absolute numbers of CD4+ and especially CD8+ lymphocytes were found to be decreased; CD4/CD8 ratio increased, and NK cell activity was depressed. After cyanocobalamin treatment, absolute numbers and percentage of lymphocyte subgroups were elevated. Increased CD4/CD8 ratio and depressed NK cell activity were restored and levels of C3, C4, and immunoglobulins were elevated. Conclusion: These findings suggest that vitamin B12 has important immunomodulatory effects on cellular immunity, and abnormalities in the immune system in pernicious anemia are restored by vitamin B12 replacement therapy.
Toxicological & Environmental Chemistry | 2006
Nihayet Bayraktar; A. Alev Karagözler; Mehmet Refik Bayraktar; Serap Titretir; Engin M. Gozukara
The aim of this study was to examine occupation-associated effects on blood cytokine and immunoglobulin g (IgG) levels, antioxidant enzyme activities (SOD, GSHPx, and catalase), nitrite and nitrate levels, and malondialdehyde (MDA) concentrations in gas station workers (GSWs). Trace elements (Cu, Zn, and Pb) in serum, and the amount of hemoglobin in erythrocytes were also determined. Forty male GSWs and 30 male controls were included in the study. No significant difference was observed between the hemoglobin levels of GSWs and those in controls. Proinflammatory cytokine levels, such as tumor necrosis factor-α and interleukin-8 were significantly increased in GSWs’ sera. Interleukin-1β and interleukin-6 were below the detection limit of the assay in both the groups. Cytokine receptor interleukin 2R concentration and IgG levels were also significantly increased. Approximately, two-fold increase in nitrite and nitrate concentrations was found in GSWs’ sera. Erythrocyte antioxidant enzyme levels were significantly lower in GSWs’ blood. MDA concentration, a measure of lipid peroxidation, was found to be significantly elevated. Zn levels were significantly decreased, whereas Cu and Pb levels were increased in GSWs’ sera. Smoking was not found to be a major confounder for the association between exposure and blood parameters.
International Journal of Urology | 2006
Süleyman Kılıç; Nihayet Bayraktar; Ali Beytur; Hüseyin Ergin; Mehmet Refik Bayraktar; Mücahit Eğri
Aim: To determine nitric oxide (NO) levels in serum, urine, tumor tissue and non‐malignant adjacent tissue in bladder cancer patients compared with those in patients with a non‐neoplastic genitourinary disease and to evaluate postoperative serum and urine NO change.
Cell Biochemistry and Function | 2005
Irfan Kuku; Ismet Aydogdu; Nihayet Bayraktar; Emin Kaya; Ömer Akyol; M. Ali Erkurt
Intensive Care Medicine | 2004
Semra Demirbilek; Mehmet Ozcan Ersoy; Savaş Demirbilek; Abdurrahman Karaman; Melih Akın; Mehmet Refik Bayraktar; Nihayet Bayraktar