Tıp Fakültesi / Faculty of Medicine

Permanent URI for this collectionhttps://hdl.handle.net/11727/1403

Browse

Filters

2014 - 2019202020 - 20239

Settings

Author: search.filters.author.Bayraktar, Nilufersearch.filters.applied.f.language: search.filters.language.eng

Search Results

Now showing 1 - 10 of 29
  • No Thumbnail Available
    Item
    User Verification of Abbott Alinity HQ Hematology Analyzer
    (2023) Bayraktar, Nilufer; Topcu, Deniz Ilhan; 0000-0002-1219-6368; 0000-0002-7886-3688; E-3717-2019; Y-8758-2018
    Objectives This study aims to evaluate the performance characteristics of the Alinity HQ hematology analyzer in a routine laboratory setting.Methods In the study, precision (short-term and long-term precision), accuracy (method comparison with Abbott Cell Dyn Ruby and estimation of bias), confirmation of a background (Limit of Blank, LoB), and carry-over were used to evaluate the performance of Alinity HQ as recommended by ICSH, CLSI guidelines EP15-A3, EP09, EP17A2, and H26-A2. Acceptance criteria were based on manufacturer technical specifications and the EFLM Biological Variation Database.Results According to the short-term precision results, except for mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC), all measurements exhibited coefficient variations (CV) lower than their verification limits. Basophil, eosinophil, and monocyte counts, as well as mean corpuscular hemoglobin (MCH), MCHC, and red cell distribution width standard deviation (RDW-SD), did not meet the allowable imprecision criteria for the long-term precision study. The estimated bias for all analytes was within verification limits. However, the method comparison study showed concentration-dependent variations for MCHC, MCH, and mean platelet volume (MPV) parameters. Furthermore, the correlation of parameters between Alinity HQ and Cell Dyn Ruby ranged from 0.46 to 1.00. The LoB and carry-over studies demonstrated satisfactory performance for the Alinity HQ analyzer.Conclusions Although some parameters had higher CVs than expected and concentration-dependent bias, the overall analytical performance of Alinity HQ was found to be satisfactory. Alinity HQ is an accurate, highly precise analyzer with good analytical performance, suitable for high-volume laboratories.
  • No Thumbnail Available
    Item
    Effects of Pesticides on Testes at Ultrastructural and Hormonal Levels
    (2023) Unlukal, Nejat; Karabay, Gulten; Dagdeviren, Attila; Bayraktar, Nilufer; Guvercin, Ayse Canan Yazici; Tekindal, Mustafa Agah; 0000-0002-8107-4882
    Aim: Endocrine disruptors damage the functions of hormones in the body by imitating or blocking them. They and their metabolites change hormone levels and functions in the body. Pesticides constitute a significant group of endocrine disruptors. It is known that Profenofos, and 4-chloro-2-methylphenoxyacetic acid (MCPA) have negative effects on male genital system. However, studies about the effect on ultrastructural size are limited. Therefore, it is intended to compare the effect of MCPA and Profenofos on the ultrastructural level of the testes. Material and Methods: There were three groups in the study (control, Profenofos, MCPA), each of which included ten fourteen-week-old male rats. Electron microscopy and biochemical investigation were performed on the excluded tissues of the testes. Results: In histopathologic investigations, spermatogenesis was healthy in the control group. Structural degenerations were observed on spermatogenic cells and Sertoli cells in the profenofos group. The gaps among spermatogenetic cells, cellular degeneration (i.e. structural damage) in the MCPA group was more obvious than in the Profenofos group. Considering the biochemical results, a significant decrease in testosterone level was observed in the animals receiving both profonefos and MCPA. Discussion: Profenofos and MCPA prevent the healthy continuation of spermatogenesis and therefore may cause infertility.
  • No Thumbnail Available
    Item
    The Effects of Niacin on Inflammation in Patients with Non-ST Elevated Acute Coronary Syndrome
    (2015) Karacaglar, Emir; Atar, Ilyas; Altin, Cihan; Yetis, Begum; Cakmak, Abdulkadir; Bayraktar, Nilufer; Coner, Ali; Ozin, Bulent; Muderrisoglu, Haldun; 0000-0002-2538-1642; 0000-0002-5711-8873; 0000-0003-3821-412X; 0000-0002-7886-3688; 0000-0002-9635-6313; 27122858; ABI-6723-2020; ABD-7321-2021; AAD-9938-2021; Y-8758-2018; AAG-8233-2020
    Background: In this study, we aimed to evaluate the effects of niacin on high sensitivity C reactive protein (hs-CRP) and cholesterol levels in non-ST elevated acute coronary syndrome (NSTE-ACS) patients. Methods: In this prospective, open label study, 48 NSTE-ACS were randomized to niacin or control group. Patients continued their optimal medical therapy in the control group. In the niacin group patients were assigned to receive extended-release niacin 500 mg/day. Patients were contacted 1 month later to assess compliance and side effects. Blood samples for hs-CRP were obtained upon admittance to the coronary care unit, in the third day and in the first month of the treatment. Fasting blood samples for cholesterol levels were obtained before and 30 days after the treatment. The primary end point of the study was to evaluate changes in hs-CRP, cholesterol levels, short-term cardiovascular events, and the safety of niacin in NSTE-ACS. Results: Baseline demographic, clinical and laboratory characteristics were similar between the two groups. Logarithmic transformation of baseline and 3rd day hs-CRP levels were similar between the groups; but 1 month later, logarithmic transformation of hs-CRP level was significantly lower in the niacin group (0.43 +/- 0.39 to 0.83 +/- 0.91, p = 0.04). HDL-C level was significantly increased in the niacin group during follow-up. Drug related side effects were seen in 7 patients in the niacin group but no patients discontinued niacin. Conclusions: Our findings demonstrate that lower dose extended release niacin can be used safely and decreases hs-CRP and lipid parameters successfully in NSTE-ACS patients.
  • No Thumbnail Available
    Item
    The Notch Pathway Is A Critical Regulator of Angiogenesis in A Skin Model of Ischemia
    (2015) Abbas, Ozan L.; Borman, Huseyin; Terzi, Yunus K.; Terzi, Aysen; Bayraktar, Nilufer; Yazici, Ayse C.; 0000-0002-1225-1320; 0000-0002-7886-3688; 0000-0001-5612-9696; 0000-0002-3132-242X; 25834117; F-7546-2013; Y-8758-2018; B-4372-2018; AAS-6810-2021
    The Notch pathway is definitely required for normal vascular development. Although the contribution of Notch in postnatal angiogenesis is the focus of intense investigation, the implication of Notch in reparative neovascularization in the skin remains unexplored. In this study, we investigated Notch changes using a skin model of ischemia. Thirty Sprague-Dawley rats were divided into two groups. In the surgery group (n = 24), a caudally based dorsal skin flap was raised and sutured back into its initial position. In the control group, no surgical procedure was performed. Tissue biopsies were obtained at different time intervals. Tissue specimens were assessed for Delta-like ligand 4 (DLL4) and vascular endothelial growth factor (VEGF) gene expression by real-time polymerase chain reaction (PCR). Immunohistochemical staining was used for detection of DLL4 in tissue materials. Quantitative assessment of skin flap microvasculature was made. Compared with normoperfused tissue, VEGF and DLL4 expressions increased significantly (p < 0.01). Immunohistochemical analysis revealed weak and patchy expression of DLL4 in microvascular endothelial cells of normoperfused tissues. Conversely, DLL4 expression was upregulated in capillary endothelial cells after ischemia. In conclusion, in this study we have shown that the Notch ligand DLL4 is upregulated in skin tissue after ischemia. A deeper understanding of these fundamental principles will aid in the development of new avenues for the treatment of blood vessel-related skin pathologies.
  • No Thumbnail Available
    Item
    Relationship Between Inflammation, Sex Hormone Profile and Sexual Dysfunction in Female Patients Receiving Different Types of Renal Replacement Therapy
    (2014) Altunoglu, Alpaslan; Yavuz, Demet; Canoz, Mujdat Batur; Yavuz, Rahman; Karakas, Latife Atasoy; Bayraktar, Nilufer; Colak, Turan; Sezer, Siren; Ozdemir, Fatma Nurhan; Haberal, Mehmet; https://orcid.org/0000-0002-4082-6320; https://orcid.org/0000-0001-7369-5470; https://orcid.org/0000-0002-7886-3688; https://orcid.org/0000-0002-8372-7840; https://orcid.org/0000-0002-7326-8388; https://orcid.org/0000-0002-5682-0943; https://orcid.org/0000-0002-3462-7632; ABG-9980-2021; AEY-5060-2022; Y-8758-2018; AAJ-8554-2021; JYQ-2550-2024; AAK-1697-2021; AAJ-8097-2021
  • No Thumbnail Available
    Item
    Oxidative Stress in Maintenance Hemodialysis Patients
    (2014) Uyar, Mehtap Erkmen; Bal, Zeynep; Bayraktar, Nilufer; Demirci, Bahar Gurlek; Sayin, Burak; Sezer, Siren; https://orcid.org/0000-0002-7886-3688; https://orcid.org/0000-0001-8287-6572; https://orcid.org/0000-0002-7326-8388; IAO-2608-2023; AAZ-5795-2021; Y-8758-2018; J-3707-2015; JYQ-2550-2024
  • No Thumbnail Available
    Item
    Inhibition of the Notch Pathway Promotes Flap Survival by Inducing Functional Neoangiogenesis
    (2015) Abbas, Ozan Luay; Borman, Huseyin; Terzi, Yunus K.; Terzi, Aysen; Bayraktar, Nilufer; Ozkan, Burak; Yazici, Ayse C.; 0000-0002-7886-3688; 0000-0003-3093-8369; 0000-0002-1225-1320; 0000-0002-3132-242X; 0000-0001-5612-9696; 25180956; Y-8758-2018; AAI-5063-2020; F-7546-2013; AAS-6810-2021; B-4372-2018
    Objective The Notch pathway seems to function as an antiangiogenic factor, negatively regulating the sprouting effect of vascular endothelial growth factor (VEGF). This function is well defined in embryonic and tumor vasculature. However, little is known about its function in ischemia-induced angiogenesis. In the first part of this study, we investigated the role of Notch in reparative angiogenesis after ischemia. In the second part, we hypothesized that anti-Notch therapy will result in increased angiogenic sprouting. We analyzed the effect of Notch inhibition in the induction of angiogenic sprouting. Methods In the first part, we investigated the effect of ischemia on the Notch ligand delta-like ligand 4 (DLL4). Twenty rats were divided equally into 2 groups. In the surgery group, dorsal skin flap was used as model of ischemia. In the control group, no surgical procedure was performed. DLL4 and VEGF gene expressions were assessed. Immunohistochemical staining was used for detection of DLL4 in tissue materials. Plasma levels of VEGF and DLL4 were measured. In the second part, we investigated the effect of Notch inhibition using a gamma-secretase inhibitor (GSI) on inducing neoangiogenesis. Twenty rats were assigned to 2 equal groups. In all animals, dorsal skin flap was raised and sutured back into its bed. Animals in the GSI-treated group received GSI intravenously after surgery for 3 days. Saline was administered in the control group. Necrotic area measurements, microangiography, and histologic evaluations were performed to compare groups. Results In the first part, VEGF and DLL expressions increased in ischemic tissues (P < 0.01). Immunohistochemical analysis revealed that DLL4 expression was upregulated in capillary endothelial cells after ischemia. Plasma levels for VEGF and DLL4 were higher in the animals that underwent surgery (P < 0.01). In the second part, GSI treatment resulted in higher flap survival rates (P < 0.05). Microscopic analysis exhibited increase in the number of microvascular structures after GSI treatment (P < 0.05). Microangiographic evaluation showed that neovascularization increased in the GSI-applied flaps. Conclusions We present an evidence for the importance of the Notch pathway in the regulation of ischemia-induced angiogenesis. Notch inhibition promotes flap survival by creating a neovasculature that has an increase in vascular density.
  • No Thumbnail Available
    Item
    Evaluation of Serum Leptin and Adiponectin Levels in Obese and Lean Asthmatic Children
    (2015) Koksal, Burcu Tahire; Ozbek, Ozlem Yilmaz; Bayraktar, Nilufer; Kinik, Sibel Tulgar; Yazici, Ayse Canan; 0000-0003-2974-9579; 0000-0002-7886-3688; 0000-0002-3132-242X; 0000-0001-9580-7656; AAJ-2034-2021; Y-8758-2018; AAS-6810-2021; HKW-0623-2023; AAF-2109-2021
    Background: Adipokines have been claimed for the link between obesity and asthma. The aim of the present study was to evaluate the roles of leptin and adiponectin in children with asthma and/or obesity and their effect on pulmonary functions. Methods: Obese (n=71) and lean asthmatics (n=72), obese non-asthmatics (n=46), and lean healthy children (n=49) were included in the study. Serum leptin and adiponectin levels were compared according to groups and sex. Results: Mean leptin levels of obese asthmatics were higher than those of lean asthmatics (13.19.1 vs. 3.7 +/- 4.4; p<0.001). Serum adiponectin levels of lean asthmatics (16 +/- 7.1) were significantly higher than those of obese asthmatics (12.1 +/- 6.9; p<0.001) and of their lean healthy (13.2 +/- 5.9; p<0.05) counterparts. In obese asthmatics, adiponectin levels were positively correlated with the forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio, and serum leptin levels were inversely correlated with forced expiratory flow (FEF25-75). Leptin/adiponectin ratio was inversely correlated with FEV1/FVC ratio in lean and obese asthmatic patients. Conclusions: The present findings suggest that adiponectin may have protective disease modifying effect(s) in asthmatic children. Anti-inflammatory mechanisms regarding adiponectin may work better in girls than in boys.
  • No Thumbnail Available
    Item
    AMH Levels at Central Precocious Puberty and Premature Thelarche: Is It A Parameter?
    (2015) Sahin, Nursel Muratoglu; Kinik, Sibel Tulgar; Tekindal, Mustafa Agah; Bayraktar, Nilufer; 0000-0002-7886-3688; 0000-0002-4060-7048; 0000-0002-8215-0146; 26226120; Y-8758-2018; U-9270-2018; AAA-1266-2019
    Background: The possible difference of antimllrin hormone (AMH) levels at central precocious puberty (CPP) and premature thelarche (PT) has not been properly evaluated. Objective/hypothesis: By evaluating AMH levels in girls with diagnosed CPP and PT, we aim to show the change of AMH levels at the pubertal onset. Subjects: Sixty-five girls who have breast development before the age of 8 years and 25 healthy girls were enrolled in the study. Methods: The subjects were divided into two groups as CPP and PT, according to results of GnRH test. AMH levels were determined in the two groups. Results: The mean AMH levels of the CPP group were significantly lower than those in the PT group (13.57 +/- 9.85 pmol/L and 58.42 +/- 12.78 pmol/L, respectively, p=0.022). Conclusion: These results suggest that the AMH levels decrease in the duration of the hypothalamus-pituitaryovarian axis activation. We thought that AMH might/may be a marker for distinguishing between CPP and PT.
  • No Thumbnail Available
    Item
    Evaluation of Angiopoietin 1 and 2, Vascular Endothelial Growth Factor, and Tumor Necrosis Factor Alpha Levels in Asthmatic Children
    (2014) Koksal, Burcu Tahire; Ozbek, Ozlem Yilmaz; Bayraktar, Nilufer; Yazici, Ayse Canan; https://orcid.org/0000-0001-9580-7656; https://orcid.org/0000-0003-2974-9579; https://orcid.org/0000-0002-7886-3688; https://orcid.org/0000-0002-3132-242X; 25584916; AAF-2109-2021; AAJ-2034-2021; Y-8758-2018; AAS-6810-2021
    Asthma is characterized by chronic airway inflammation that is associated with structural changes termed airway remodeling. Recently, cytokines/mediators that augment inflammation have been attracting attention in this field. The aim of this study was to evaluate serum angiopoietin (Ang)-1, Ang-2, vascular endothelial growth factor (VEGF), and tumor necrosis. factor (TNF) alpha values, which have important roles in inflammation, angiogenesis, and remodeling in astlunatic children. We also documented correlations between demographic features, duration of asthma, and pulmonary function test (PFT) parameters. Randomly selected 40 children (20 male and 20 female children, aged 6-16 years) with mild or moderate persistent asthma and 32 healthy children (15 male and 17 female children, aged 6-16 years) enrolled in the study. All asthmatic children had been using inhaled corticosteroids at least for the last 3 months. Serum Ang-1 levels were significantly lower in asthmatic children than those in normal controls. The Ang-1/Ang-2 ratio was also significantly lower in asthmatic children compared with those in normal controls (p < 0.01). However, serum Ang-2, VEGF, and TNF-alpha levels were similar in the two groups. A significant positive correlation was found between VEGF and duration of asthma. No correlation between sewn Aug-I, Ang-2, VEGF values, and PFT parameters was obtained. On the other hand, significant negative correlation was detected between serum TNF-alpha and forced expiratory volume in 1 second. We have shown that serum Aug-1 levels and Ang-1/Ang-2 ratio were significantly reduced and balance was toward Ang-2 in asthmatics children. This process may lead to inflammation, destabilization of blood vessels, and trigger remodeling.