Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Nilufer Bayraktar is active.

Publication


Featured researches published by Nilufer Bayraktar.


Blood Coagulation & Fibrinolysis | 2010

Prevention of contrast-induced impairment of renal function by short-term or long-term statin therapy in patients undergoing elective coronary angiography

Sadik Acikel; Haldun Muderrisoglu; Aylin Yildirir; Alp Aydinalp; Elif Sade; Nilufer Bayraktar; Uğur Abbas Bal; Bülent Özin

A decline in kidney function after contrast exposure is associated with a high risk of morbidity and mortality during hospitalization and over long-term periods. Several retrospective and recent prospective clinical trials have shown that statin therapy might prevent contrast-induced nephropathy in patients undergoing percutaneous coronary intervention. In this study, we aimed to assess the effects of statin therapies on renal function parameters in patients undergoing elective coronary angiography. One hundred and sixty patients undergoing elective coronary angiography were randomized equally into two groups: atorvastatin 40 mg/day group (statin started 3 days before coronary angiography) and an untreated control group. An additional 80 patients were included as a chronic statin therapy group. Serum creatinine, serum cystatin C, and glomerular filtration rate (GFR) were measured before and 48 h after coronary angiography. Cockcroft–Gault and Modification of Diet in Renal Disease (MDRD) equations were used to determine GFR. After coronary angiography, serum creatinine and GFR determined by MDRD were significantly better in patients using atorvastatin than those in controls (P = 0.002 and P = 0.004, respectively). Postprocedure serum creatinine, cystatin C, and GFR determined by MDRD were also significantly better in chronic statin therapy group than those in controls (P = 0.006, P = 0.003, and P = 0.004, respectively). There were no differences in renal function parameters between the short-term atorvastatin group and the chronic statin therapy group. Our data demonstrate that the use of short-term atorvastatin and chronic statin therapy may have a role in protecting renal function after elective coronary angiography.


Epilepsia | 2009

Elevated CK-MB mass and plasma brain-type natriuretic peptide concentrations following convulsive seizures in children and adolescents: Possible evidence of subtle cardiac dysfunction

Füsun Alehan; Ilknur Erol; Tuba Cemil; Nilufer Bayraktar; Ersin Ogus; Kürşad Tokel

Purpose:  To evaluate the presence of myocardial injury during convulsive seizures in children and adolescents by determining serum concentrations of cardiac troponin I (cTnI), creatine kinase‐MB mass (CK‐MB mass), and plasma brain‐type natriuretic peptide (BNP).


Fertility and Sterility | 2007

Polycystic ovary syndrome is associated with elevated plasma soluble CD40 ligand, a marker of coronary artery disease

Mesut Oktem; Emel Ebru Ozcimen; Ayla Uckuyu; Ibrahim Esinler; Baris Onder Pamuk; Nilufer Bayraktar; Sevsen Kulaksizoglu; Hulusi B. Zeyneloglu

OBJECTIVE To determine the level of plasma soluble CD40 ligand (sCD40L) in patients with polycystic ovary syndrome (PCOS). DESIGN Prospective study. SETTING Baskent University School of Medicine in Turkey. PATIENT(S) Thirty-one patients with PCOS and 31 non-PCOS (control) patients. INTERVENTION(S) Determination of plasma sCD40L and homocysteine levels. MAIN OUTCOME MEASURE(S) Plasma sCD40L, fasting glucose, fasting insulin, homeostatic model assessment insulin resistance index (HOMA-IR), LH, FSH, E(2), total T, DHEAS, total cholesterol, high- and low-density lipoprotein cholesterol, triglyceride, homocysteine, and high-sensitivity C-reactive protein (hsCRP). RESULT(S) The mean serum fasting insulin and HOMA-IR levels were significantly higher in the PCOS group. The mean serum homocysteine level was significantly higher in the PCOS group. Despite a trend for higher high-sensitivity C-reactive protein levels in the PCOS group, the difference did not reach statistical significance. The mean plasma sCD40L level in the PCOS group was significantly higher than that in the control group (5.14 +/- 3.65 ng/mL vs. 3.45 +/- 2.64 ng/mL, respectively). CONCLUSION(S) Polycystic ovary syndrome is associated with elevated levels of sCD40L and homocysteine.


Journal of Glaucoma | 2010

Aqueous humor and plasma levels of vascular endothelial growth factor and nitric oxide in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma.

Mehmet Borazan; Aylin Karalezli; Cem Küçükerdönmez; Nilufer Bayraktar; Sevsen Kulaksizoglu; Ahmet Akman; Yonca A. Akova

PurposeTo investigate levels of vascular endothelial growth factor (VEGF) and nitric oxide (NO) in the aqueous humor and plasma of patients with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG), compared with controls. MethodsThis prospective study involved 37 patients with PXS, 15 with PXG, and 32 control subjects in whom cataract surgery was indicated. Aqueous humor and plasma VEGF and NO levels were measured with enzyme-linked immunosorbent assay and chemiluminescence methods, respectively. ResultsAqueous humor and plasma VEGF concentrations were higher in patients with PXS and PXG than in controls (P<0.001). Aqueous humor NO concentrations were higher in patients with PXS and PXG than in controls (P<0.05 and P=0.001, respectively). Plasma NO concentrations did not differ between the 3 groups. Aqueous humor and plasma VEGF and NO levels were not significantly different in patients with PXS versus PXG. VEGF and NO levels showed no significant correlation among the 3 groups (P>0.05). ConclusionsElevated aqueous humor VEGF and NO levels and plasma VEGF concentrations in eyes with PXS and PXG can be explained by the ischemic nature of these disorders. The lack of correlation between VEGF and NO levels may indicate impaired downregulation, which may have a role in the progression to PXG.


Human Reproduction | 2009

Doxycycline causes regression of endometriotic implants: a rat model.

P. Akkaya; Gogsen Onalan; Nihan Haberal; Nilufer Bayraktar; Baris Mulayim; Hulusi B. Zeyneloglu

BACKGROUND Doxycycline (Dox) has a number of non-antibiotic properties. One of them is the inhibition of matrix metalloproteinase (MMP) activity. The aim of this study was to assess the effects of Dox in a rat endometriosis model. METHODS Endometriosis was surgically induced in 40 rats by transplanting of endometrial tissue. After 3 weeks, repeat laparotomies were performed to check the implants and the animals were randomized into four groups: Group I, low-dose Dox (5 mg/kg/day); Group II, high-dose Dox (40 mg/kg/day); Group III, leuprolide acetate 1 mg/kg single dose, s.c.; and Group VI (controls), no medication. The treatment, initiated on the day of surgery and continuing for 3 weeks, was administered to the study groups. Three weeks later, the rats were euthanized and the implants were evaluated morphologically and histologically for immunoreactivity of MMP-2 and -9, and interleukin-6 (IL-6) concentration in the peritoneal fluid was assayed. RESULTS Treatment with leuprolide acetate, or high-dose or low-dose Dox caused significant decreases in the implant areas compared with the controls (P = 0.03, P = 0.006, and P = 0.001, respectively). IL-6 levels in peritoneal fluid decreased in Group I (P = 0.02) and Group III (P < 0.05). MMP H scores were significantly lower in the group that received low-dose Dox in both epithelial and stromal MMP-2 and -9 immunostaining when compared with the control group [P = 0.048, P = 0.002, P = 0.007 and P = 0.002, respectively, MMP-2 (epithelia), MMP-2 (stroma), MMP-9 (epithelia) and MMP-9 (stroma)]. CONCLUSIONS Low-dose Dox caused regression of endometriosis in this experimental rat model.


Journal of Clinical Laboratory Analysis | 2013

The Relationship Between Serum Fetuin-A, Cystatin-C Levels, and Microalbuminuria in Patients With Metabolic Syndrome

Bülent Huddam; Alper Azak; Gülay Koçak; Nilufer Bayraktar; Siren Sezer

The metabolic syndrome, syndrome X, is a group of metabolic disorders in which insulin resistance plays a pivotal role. The MS is an important risk factor for subsequent development of type 2 diabetes and cardiovascular disease. Fetuin‐A is a liver derived blood protein that acts as effective inhibitor of soft tissue calcification. Cystatin C is a useful marker in measuring glomerular filtration rate. Moreover, recently it has been suggested that cystatin C may be a potential biomarker for detecting microalbuminuria. Microalbuminuria (MA) is a strong indicator of morbidity related to cardiovascular disorders, and is currently considered a novel diagnostic criterion for MS. It has been also demonstrated that the increased serum fetuin‐A levels is associated with several parameters of MS. In this study, we attempted to investigate the relationship between serum fetuin‐A, cystatin‐C levels and microalbuminuria in patients with MS.


Journal of Pediatric Endocrinology and Metabolism | 2011

The effect of corrective surgery on serum IGF-1, IGFBP-3 levels and growth in children with congenital heart disease.

Ozge Surmeli-Onay; Nimet Cindik; Sibel Tulgar Kinik; Suleyman Ozkan; Nilufer Bayraktar; Kürşad Tokel

Abstract The aim of this study is to evaluate growth and insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels in infants with congenital heart disease (CHD) pre- and postoperatively over a period of a year. Anthropometric values and serum levels of IGF-1 and IGFBP-3 of 40 infants with CHD (20 cyanotic and 20 acyanotic) were compared with 32 healthy controls. Acyanotic infants and infants with pulmonary hypertension (PH) presented significantly more growth failure. Preoperatively, serum IGF-1 and IGFBP-3 levels were lower in the acyanotic group than the cyanotic and the control groups (p=0.22; p<0.01). The upward trend in IGF-1 and IGFBP-3 levels in this year-long study demonstrated that the values in the third month and the first year were higher than the preoperative values (p<0.05). The parallel increase of weight gain and IGF-1, IGFBP-3 levels were the best evidence that these parameters are good nutritional indicators. Timing the corrective surgery before chronic malnutrition or PH develops is an important issue to maintain a normal growth for children with CHD.


Fertility and Sterility | 2009

Fenofibrate causes regression of endometriotic implants: a rat model

Gogsen Onalan; Hulusi B. Zeyneloglu; Nilufer Bayraktar

Fenofibrate -a peroxisome proliferator-activated receptor-a agonist- is an angiostatic agent that is commonly used in human liver diseases, therefore it may interfere with the angiogenetic process required for endometriosis. In a rat endometriosis model, we demonstrated that peritoneal implant areas and vascular endothelial growth factor levels in the peritoneal flud were significantly decreased in high dose or low dose finofibrate and luprolide acetate treated groups compared to control.


Journal of Burn Care & Research | 2013

Destructive pulmonary effects of smoke inhalation and simultaneous alterations in circulating IL-6, TNF-α, and IFN-γ levels at different burn depths: an experimental study on rats

Ayse Ebru Sakallioglu Abali; H. Karakayali; Özdemir Bh; Nilufer Bayraktar; Ozan Luay Abbas; Mehmet Haberal

The current study sought to examine the interactions between inflammatory and immune events in the lung and circulating interleukin-6 (IL-6), tumor necrosis factor-&agr; (TNF-&agr;), and interferon-&ggr; (IFN-&ggr;) levels at different burn depths with concomitant smoke inhalation in the rat model. Forty-eight female Sprague-Dawley rats were divided into six groups: S, sham; P, partial-thickness burns; F, full-thickness burns; I, inhalation; Pi, partial-thickness burns + inhalation; and Fi, full-thickness burns + inhalation. Blood samples and lung biopsies were obtained 24 hours later. Blood levels of IL-6, TNF-&agr;, and IF-&ggr; were measured with enzyme-linked immunosorbent assay. The proportions of CD3(+) lymphocytes and CD68(+) macrophages in the biopsies were studied immunohistochemically. The most severe inflammatory changes, except the neutrophil sequestration, were observed in the Fi group. A dense amount of neutrophils was observed in the F group. Edema and massive alveolar bleeding were seen in the I, Pi, and Fi groups. The amount of CD3(+) lymphocytes were dense in the P, F, and Pi groups. The amount of CD68(+) macrophages were significantly dense in Pi, F, I, and Fi groups. IL-6, TNF-&agr;, and IF-&ggr; increased in all groups when compared to the S group. The highest IL-6 level was seen in the Fi group. TNF-&agr; significantly increased in the F, Pi, I, and Fi groups. Increase in IFN-&ggr; levels in the Pi and Fi groups was significantly higher than in the P and F groups. In concomitant smoke inhalation and skin burns, pulmonary damage and systemic inflammatory response are related and may be evaluated by blood levels of IL-6, TNF-&agr;, and IFN-&ggr; cytokines.


American Journal of Rhinology & Allergy | 2013

Evaluation of vascular endothelial growth factor A and endostatin levels in induced sputum and relationship to bronchial hyperreactivity in patients with seasonal allergic rhinitis.

İnsu Yılmaz; Nilufer Bayraktar; Koray Ceyhan; Derya Seçil; Selcen Yüksel; Zeynep Misirligil; Sevim Bavbek

Background Studies about the pathogenesis of bronchial hyperreactivity (BHR) in patients with allergic rhinitis (AR) and its relationship with lower airway remodeling are extremely limited. In this study, bronchial vascular remodeling and its relationship with BHR were evaluated by measurement of vascular endothelial growth factor A (VEGF-A) and endostatin in patients with seasonal AR (SAR). Methods The study group consisted of 30 patients with SAR (positive skin test to grass pollens) and 14 healthy controls. Induced sputum and bronchial provocation test (BPT) to methacholine (M) were performed in season. VEGF-A and endostatin levels were measured by ELISA in induced sputum supernatant. Results The percentages of eosinophils in induced sputum were significantly increased in BHR+ patients (n = 10) with SAR compared with BHR– patients (n = 20) with SAR (p < 0.001). There was no correlation between eosinophils and provocative concentration of M required to produce a 20% decrease in forced expiratory volume in 1 second. The levels of VEGF-A were significantly higher in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.014 and p = 0.04). The levels of endostatin were significantly lower in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.020 and p = 0.014). The ratio of VEGF-A/endostatin was significantly higher in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.009 and p = 0.019). Conclusion In this first study comparing the VEGF-A and endostatin levels of patients with SAR in sputum supernatant, the presence of BHR was shown to be associated with the vascular component of remodeling “angiogenesis.”

Collaboration


Dive into the Nilufer Bayraktar's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge