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ÜNAL YILDIRIM, SEMRA

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ÜNAL YILDIRIM

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SEMRA

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2016 - 20198
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End date: 2019 × Start date: 2016 ×

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Now showing 1 - 8 of 8
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    Combination of proteasome inhibitors with temozolomide to increase the anti-tumor effect in 3D culture model of glioblastoma
    (ELSEVIER SCIENCE INC, 2018) YILMAZ GÖLER, AYŞE MİNE; Unal, Semra; Gokce, Tilbe; Arslan, Sema; Yilmaz, Ayse Mine; Gunduz, Oguzhan; Karademir, Betul
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    Metabolic Biomarkers and Neurodegeneration: A Pathway Enrichment Analysis of Alzheimer's Disease, Parkinson's Disease, and Amyotrophic Lateral Sclerosis
    (MARY ANN LIEBERT, INC, 2016) KAZAN, DİLEK; Kori, Medi; Aydin, Busra; Unal, Semra; Arga, Kazim Yalcin; Kazan, Dilek
    Neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS) lack robust diagnostics and prognostic biomarkers. Metabolomics is a postgenomics field that offers fresh insights for biomarkers of common complex as well as rare diseases. Using data on metabolite-disease associations published in the previous decade (2006-2016) in PubMed, ScienceDirect, Scopus, and Web of Science, we identified 101 metabolites as putative biomarkers for these three neurodegenerative diseases. Notably, uric acid, choline, creatine, L-glutamine, alanine, creatinine, and N-acetyl-L-aspartate were the shared metabolite signatures among the three diseases. The disease-metabolite-pathway associations pointed out the importance of membrane transport (through ATP binding cassette transporters), particularly of arginine and proline amino acids in all three neurodegenerative diseases. When disease-specific and common metabolic pathways were queried by using the pathway enrichment analyses, we found that alanine, aspartate, glutamate, and purine metabolism might act as alternative pathways to overcome inadequate glucose supply and energy crisis in neurodegeneration. These observations underscore the importance of metabolite-based biomarker research in deciphering the elusive pathophysiology of neurodegenerative diseases. Future research investments in metabolomics of complex diseases might provide new insights on AD, PD, and ALS that continue to place a significant burden on global health.
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    Design and characterization of polycaprolactone-gelatin-graphene oxide scaffolds for drug influence on glioblastoma cells
    (PERGAMON-ELSEVIER SCIENCE LTD, 2019) ATASOY, BESTE MELEK; Unal, Semra; Arslan, Sema; Gokce, Tilbe; Atasoy, Beste Melek; Karademir, Betul; Oktar, Faik Nuzhet; Gunduz, Oguzhan
    Three-dimensional (3D) scaffolds that mimic in vivo tumor microenvironments can be used to study tumor response to anticancer treatments, since most preclinical combination treatment strategy for anti-glioma were evaluated with traditional 2D cell culture. In this research, the nanofiber scaffolds of polycaprolactone (PCL) containing gelatin (Gel) nano/microparticles coated with different concentrations of graphene oxide (GO) and were successfully produced by combining electrospinning and electrospraying techniques. Scanning electron microscope (SEM), Fourier-transform infrared (FT-IR) spectroscopy and mechanical testing were used to characterize the structure and properties of the composites. The results show that gelatin and graphene particles can be well dispersed in the polycaprolactone nanofiber matrix by using the combination technique of electrospinning and electrospraying. The presence of 1 wt% graphene oxide increased mechanical strength of PCL/Gel scaffold and was found to be well consistent with the drug treatments (temozolomide and bortezomib) and radiotherapy by not showing additional toxicity.
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    Effects of Polymethylsilsesquioxane concentration on morphology shape of electrosprayed particles
    (ELSEVIER SCIENCE BV, 2018) OKTAR, FAİK NÜZHET; Unal, Semra; Oktar, Faik Nuzhet; Gunduz, Oguzhan
    The investigation of unique sizes and shapes as they relate to various properties has become a great study for large field applications. Polymethylsilsesquioxane (PMSQ) particles are produced by electrospraying. Morphology of the electrosprayed particles develops from the needle-like to star-like particles by controlling the concentration of the polymer solution. Therefore, electrospraying process instead of conventional methods has opened up an alternative for the fabrication of particles by controlling with three main parameters (applied voltage, flow rate and concentration of the polymer) that are used to manipulate their morphologies during preparation. (C) 2018 Elsevier B.V. All rights reserved.
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    Production and characterization of calcium phosphates from marine structures: The fundamentals basics
    (Springer, 2019-01-01) ÜNAL YILDIRIM, SEMRA; GÜNDÜZ, OĞUZHAN; OKTAR, FAİK NÜZHET; ÜNAL S., GÜNDÜZ O., AKYOL S., Ben Nissan B., OKTAR F. N.
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    Synthesis, characterization, and biological properties of composites of hydroxyapatite and hexagonal boron nitride
    (WILEY, 2018) OKTAR, FAİK NÜZHET; Unal, Semra; Ekren, Nazmi; Sengil, Ahmet Z.; Oktar, Faik N.; Irmak, Ster; Oral, Ozlem; Sahin, Yesim M.; Kilic, Osman; Agathopoulos, Simeon; Gunduz, Oguzhan
    Hydroxyapatite (HA), obtained from bovine bones, was successfully reinforced with hexagonal boron nitrite (h-BN). h-BN/HA composites, with BN content up to 1.5 wt %, were sintered at various temperatures between 1000 and 1300 degrees C, in air. Well-sintered samples were obtained after sintering at 1200 and 1300 degrees C. The presence of h-BN contributed to dense, fine, and well-crystallized microstructure. The results of X-ray diffraction analysis and FT-IR spectroscopy showed that the produced composites comprised biphasic beta-TCP/HCA (HCA: carbonate partially substituted HA). High values of mechanical properties were achieved, namely compression strength 155 MPa for the sample 0.5% h-BN/HA and Vickers microhardness of 716 HV for the samples 1.5% h-BN/HA, both sintered at 1300 degrees C. U2OS human bone osteosarcoma proliferation and cell viability showed no adverse effect in the presence of h-BN/HA, suggesting the potential use of the produced materials as safe biomaterials in bone tissue engineering. (C) 2017 Wiley Periodicals, Inc.
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    3D printing of chitosan/ poly(vinyl alcohol) hydrogel containing synthesized hydroxyapatite scaffolds for hard-tissue engineering
    (ELSEVIER SCI LTD, 2019) KARTAL, İLYAS; Ergul, Necdet Mekki; Unal, Semra; Kartal, Ilyas; Kalkandelen, Cevriye; Ekren, Nazmi; Kilic, Osman; Chi-Chang, Lin; Gunduz, Oguzhan
    In recent years, 3D printed scaffolds becoming a widespread tool, which supports the repair mechanism of natural tissues. In order to support this knowledge, we used 3D printing methods to fabricated Chitosan (CH)/poly(vinyl alcohol)(PVA)-based scaffolds contains with a various ratio of hydroxyapatite (HA) (2.5, 5, 10, and 15 wt%). These composited scaffolds were further characterized for their chemical, morphological, mechanical, and biocompatibility properties. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), swelling test, and compressive strength test were performed to reveal structural, mechanical and chemical characteristics of scaffolds. Among others, 15 wt% HA contained group demonstrated significantly superior and beneficial features in printing quality. Also, the results reveal that scaffolds have similar elastic modulus to natural bone. Bone morphogenetic protein-2 (BMP-2) protein was added to the most successful mechanically produced sample. As a result, it was shown that Chitosan/PVA/HA (15 wt%) with BMP-2 tissue scaffold could form a three-dimensional natural extracellular scaffold suitable for human mesenchymal stem cells. Altogether, these results show that hydroxyapatite added scaffolds produced may be a promising approach for bone tissue engineering applications.
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    Tektal plate gli̇omlarında gamma kni̇fe radyocerrahi̇si
    (2019-04-22) PINAR, ERTUĞRUL; ŞİMŞEK, İSMAİL; BAYRİ, YAŞAR; BAYRAKLI, FATİH; ATASOY, BESTE MELEK; ÜNAL YILDIRIM, SEMRA; Pınar E., Şimşek İ., Bayri Y., Bayraklı F., Ünal Yıldırım S., Atasoy B. M.
    GİRİŞ: Tektal plate gliomları beyin sapı gliomlarının genellikle daha iyi seyirli bir alt grubudur. Yerleşim yeri nedeniyle biyopsi ve cerrahi eksizyonun güçlüğü stereotaktik radyocerrahi/radyoterapi tedavi seçeneklerinin tedaviler arasında yer almasını sağlamıştır. Bu çalışmada, Gamma Knife radyocerrahisi uygulanan tektal plate yerleşimli tümörlerin sonuçlarının bildirilmesi amaçlanmıştır. GEREÇ-YÖNTEM: Mart 2010 ve Kasım 2018 tarihleri arasında tedavi yapılmış 15’i kadın toplam 26 hasta geriye dönük olarak incelendi. Ortalama yaş 32 idi. On iki hasta hidrosefali tablosu ile başvurmuştu. Yedi hastaya sadece endoskopik III. ventrikülostomi (ETV), iki hastaya ventriküloperitoneal shunt (V-P shunt) ve üç hastaya ise hem ETV hem de V-P shunt cerrahisi yapılmıştı. Üç hastaya biyopsi, iki hastaya eksizyonel cerrahi yapılmıştı. Bilinen malignite tanıları olmayan hastaların radyolojik görüntülemeleri düşük dereceli glial tümör ile uyumlu idi. Hastaların Leksell stereotaktik çerçeve takılarak yapılan magnetik rezonans (MR) görüntülemeleri Leksell Gamma Knife Model B Plan 8.32’de işlendi. Mevcut lezyon %50’lik izodoz ile sardırılarak medyan 14 Gy (aralık,12-16 Gy) uygulandı. Takipte klinik ve radyolojik veriler dikkate alındı. Lokal kontrol için Kaplan- Meirer eğrisi SPSS v23.0 kullanılarak hesaplandı. BULGULAR: Medyan takip 33 ay (aralık, 3-102 ay) idi. İki hasta takipsiz kaldı. Analiz sırasında diğer tüm hastalar sağ idi. Hastaların %57’sinde tümörde radyolojik regresyon izlenirken iki hastada tam cevap izlendi. Dört (%15) hastada radyolojik progresyon izlenirken bu hastalardan birinde radyolojik yüksek dereceli glial tümör ile uyumlu bulgular nedeniyle eksternal radyoterapi ve temozolamid uygulandı. Geri kalan hastalarda hastalık progresyonu görülmedi. Takipler sırasında altı hastada tümör içi kist gelişimi, dört hastada radyonekroz, bir hastada ise tümör içi hemoraji, iki hastada peritümöral ödem, beş hastada radyolojik olarak pseudoprogresyon izlendi. ETV yapılmış olan bir hastanın GK sonrası kontrollerinde hidrosefalisinde ilerleme saptanması nedeniyle V-P shunt takıldı. Beş yıllık lokal kontrol %79,2 idi. SONUÇ: Tümörün yerleşim yeri nedeniyle doku tanılarının olmayan ancak radyolojik düşük dereceli gliomalarla uyumlu tektal plate gliomlarının tedavisinde Gamma Knife radyocerrahisi etkili bir tedavi seçeneği olarak gözükmektedir. Bununla birlikte çalışmamız daha geniş hasta sayılı çalışmalarla desteklenmelidir. Anahtar Kelimeler: Düşük Dereceli Giiomalar, Gamma Knife, Radyocerrahi, Tektal plate