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Öğe Biomimetic peptide-conjugated membranes for developing an artificial cornea(Institute of Electrical and Electronics Engineers Inc., 2022) Sunal G.; Pulat G.; Akgün I.H.; Güven S.; Yildiz Ü.H.; Karaman O.; Horzum N.The corneal endothelium is composed of a single layer of specialized endothelial cells, protecting, and nourishing the inner surface of the cornea. Corneal endothelial cells do not proliferate after birth and their number decrease with age. Trauma, inflammation, or surgical intervention can cause cell loss. When damage is extensive and the density of corneal endothelial cells decreases to a critical level, it results in corneal edema and vision loss. Besides them, when corneal endothelium has irreversible damage, the only treatment way is corneal transplantation. But there are some drawbacks such as finding donors, immune reactions, and the number of patients waiting on the transplantation lists for years. Tissue engineering approaches can provide promising alternatives for the regeneration of corneal endothelium tissue. Peptides can be used to modify and functionalize the scaffolds, allowing for the production of bioactive and biomimetic surfaces. Peptide-modified scaffold surfaces might direct and enhance the behaviors of cells. In this study, the aim was to functionalize the polycaprolactone (PCL) membranes with tissue-specific peptides and to characterize the peptide-conjugated membranes by Fourier-Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and X-ray Photoelectron Spectroscopy (XPS) analysis. The synthesized peptides were successfully conjugated on the PCL biomembranes. © 2022 IEEE.Öğe Development and characterization of injectable bone substitutes [Enjekte Edilebilir Kemik Grefilerinin Geliştirilmesi ye Karakterizasyonu](Institute of Electrical and Electronics Engineers Inc., 2017) Demirci E.A.; Atagur M.; Karaman O.In the late years, a dramatic increase in the number of commercial products has emerged in recent introduction of first injectable bone grafts. Bone substitutes developed as highly water retained hydrogel structures and calcium phosphate based ceramic composites have gained popularity especially in orthopedics and maxillofacial applications. These injectable bone grafts support bone tissue, which is absorbed by healthy tissue after implantation, allowing bone tissue regeneration. The aim of this study was to develop synthetic injectable bone grafts that do not require mixing during surgical application. © 2017 IEEE.Öğe Development of ß-TCP block grafts with tunable porosity and mechanical properties [Kontrol Edilebilir Porozite ye Mekanik Özelliklere Sahip ß-TCP Blok Greftlerin Geliştirilmesi](Institute of Electrical and Electronics Engineers Inc., 2017) Demirci E.A.; Atagur M.; Karaman O.In the scope of bone tissue engineering, there has still been great amount of demand on synthetic bone graft that induces differentiation of osteoprogenitor cells by cell-matrix interaction at the nanoscale as well as mimicking micro assembly of compact bone while providing high mechanical strength. In this study, we aimed to develop synthetic bone grafts based on beta-Tricalcium phosphate (ß-TCP) in the form of rod, block and cylinder with tunable porosity, radiopaque and mechanical properties. © 2017 IEEE.Öğe Efficacy of IKVAV Peptide on HUVEC Microtissue Growth [HUVEC Mikrodokusu Büyümesi Üzerinde IKVAV Peptidinin Etkisi](Institute of Electrical and Electronics Engineers Inc., 2018) Köken B.; Yarali Z.B.; Karaman O.The extracellular matrix (ECM) structure of the three-dimensional (3D) network of cells in body play an important role in cellular events. Cell-cell and cell-matrix interactions can be achieved in 3D cell culture systems as in vivo systems. For this reason, the loss of cell functions is less in 3D cultures than in two dimensional systems. Human umbilical cord vein endothelial cells (HUVECs) which are model cell types, are frequently used because of easily isolation and using vasculogenesis research in 3D culture. The isoleucine-Iysine-valine-alanine-valine (Ile-Lys- Val-Ala-Val (IKVAV)) sequence, one of the most effective units of laminin, is used as a support material in the ECM. IKVAV peptides can affect many cellular functions such as adhesion, proliferation, migration, metastasis, and are used in cell culture systems. The effects of IKVAV peptide on HUVEC microtissues were examined in this study. Increase in diameter was observed in microtissues incubated with concentrations of 0.5 and 1 mM peptides. Also when comparison of microtissues with and without peptide concentrations, has been shown to the IKVAV peptide increase cell viability. Compared with 0.5 and 1 mM, higher cell viability and diameter values are observed at 1 mM peptide concentration. This information supports the results of monolayer studies in the literature. © 2018 IEEE.Öğe Efficacy of sulphasalazine on lung histopathology in a murine model of chronic asthma(2008) Olmez D.; Babayigit A.; Uzuner N.; Erbil G.; Karaman O.; Yilmaz O.; Cetin E.O.; Ozogul C.Sulphasalazine is a specific inhibitor of nuclear factor kappa B (NF-? B) which plays a key role in asthma. To determine the impact of sulphasalazine in the treatment of chronic asthma, BALB/c mice were sensitized and challenged with ovalbumin. Mice with experimentally induced asthma in group I received saline, group II sulphasalazine 200 mg/kg, group III sulphasalazine 300 mg/kg, and group IV dexamethasone 1 mg/kg intraperitoneally once a day in the last 7 days of the challenge period. Histological findings of the airways were evaluated by light and electron microscopies. Dexamethasone and sulphasalazine in both doses significantly improved all airway histopathologic parameters of asthma except numbers of goblet cells. Both doses of sulphasalazine improved thicknesses of basement membrane better than dexamethasone. Dexamethasone reduced the number of mast cells better than sulphasalazine (200 mg/kg). Further studies are needed to evaluate the efficacy of sulphasalazine in the treatment of asthma. Copyright © Informa Healthcare USA, Inc.Öğe The efficacy of using RGD peptide sequence on in vitro wound healing [RGD Peptid Dizisinin in vitro Yara Iyile\+me Modelinde Kullanim Etkinliginin Belirlenmesi](Institute of Electrical and Electronics Engineers Inc., 2017) Kahraman E.; Demirci E.A.; Tanyolac Z.G.; Yarali Z.B.; Karaman O.In scientific area, many different studies are carried out to ensure the development of more effective and rapid wound healing method. Applied and developed several methods aims rapid wound healing with minimal discomfort to the patient which is also allow the movement of epithelial cells and to allow the regeneration of cells during to wound healing process with provided the ideal environment. It is known that RGD peptide sequences can support cell regeneration and increase cell adhesion by activating integrins therewithal synthesis of the peptide sequence simple and low cost, researchs in this field has gained momentum in recent years. The present study examined the effect of culture medium contain peptide sequence with concentration of 0.1 mg/ml and 0.5 mg/ml, on an in vitro wound healing model using by L929 fibroblast cells. © 2016 IEEE.Öğe Ginseng ameliorates chronic histopathologic changes in a murine model of asthma(2008) Babayigit A.; Olmez D.; Karaman O.; Bagriyanik H.A.; Yilmaz O.; Kivcak B.; Erbil G.; Uzuner N.Currently, asthma therapies are effective in reducing inflammation but airway remodeling is poorly responsive to these agents. New therapeutic options that have fewer side effects and reverse chronic changes in the lungs are essential. This study aimed to determine the efficacy of oral administration of ginseng on lung histopathology in a murine model of chronic asthma. BALB/c mice were divided into four groups: control, placebo, ginseng, and dexamethasone. All mice except those in the control group were sensitized and challenged with ovalbumin. Then, mice in the ginseng group were given 2 gr/kg per day of ginseng and mice in the dexamethasone group received 1 mg/kg per day of dexamethasone via orogastic gavage once daily for 1 week. Lung histopathology was evaluated by using light and electron microscopy in all groups. All of the chronic changes of airways in the ginseng group were significantly ameliorated when compared with the placebo group. When compared with the dexamethasone group, the ginseng group had significantly lower numbers of mast cell count. Thicknesses of basement membrane, epithelium, and subepithelial smooth muscle were not statistically different between the ginseng and dexamethasone groups. Goblet cell numbers were much more reduced in the dexamethasone group. Ginseng is effective in resolving the established chronic histopathological changes of the lungs in the murine model of asthma. Copyright © 2008, OceanSide Publications, Inc., U.S.A.Öğe Prolonged electrical stimulation of neuronal PC12 cells using a microchip [PC12 sinir hücrelerinin mikroçip üzerinde uzun süreli elektriksel stimülasyonu](Institute of Electrical and Electronics Engineers Inc., 2019) Seven F.; Golcez T.; Sahinler M.; Sendemir A.; Karaman O.; Sen M.PC12 cell line is widely used to study neuronal differentiation behavior. This cell line differentiates in the presence of nerve growth factor (NGF), resulting in protrusions called neurites, dentrites and axons. Non-invasive electrical stimulation is known to have potential for use in the control of the activity and regeneration of neuron cells. In this study, the effects of longterm electrical stimulation on the behavior of PC12 cells and their differentiation in the presence of NGF were investigated using a microchip. Electrical stimulation was performed 2 hours a day for 2 days and all day (24 hours) and the results were compared to the condition in which no electrical stimulation was applied. The results clearly showed that the cells migrated towards the electrodes and the neurite orientation was promoted due to the electrical stimulation applied. However, the protrusion per cell decreased. The findings are thought to be useful in elucidating the effects of external electrical stimulation on neuron cell. © 2019 IEEE.Öğe Role of functionalized self-assembled peptide hydrogels inin vitrovasculogenesis(Royal Society of Chemistry, 2021) Onak Pulat G.; Gökmen O.; Çevik Z.B.Y.; Karaman O.Fabrication of vascularized tissue constructs plays an integral role in creating clinically relevant tissues. Scaffold materials should be sufficiently vascularized to mimic functional and complex native tissues. Herein, we report the development of bioactive and biomimetic self-assembled peptide (SAP) hydrogels that allow the rapid formation of a vascular structurein vitro. The KLDLKLDLKLDL (KLD peptide) SAP was functionalized with laminin derived peptides IKVAV (V1) and YIGSR (V2) through direct coupling to mimic the natural extracellular matrix (ECM) and human umbilical endothelial cells (HUVECs) and mesenchymal stem cells (MSCs) cultured in 0.5% and 1% SAP hydrogels organized into vascularized structures. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) images proved the molecular integration of the nanofibrous structure in SAP hydrogels. The stability of SAP hydrogels was confirmed by rheological and degradation measurements. Bioactive peptide scaffolds enhanced significantly HUVEC/hMSC proliferation depicted by MTT analysis compared to KLD. Furthermore, the real time quantitative polymerase chain reaction (rt-PCR) was performed to analyse vascular gene expressions such as platelet/endothelial cell adhesion molecule-1 (PECAM-1), von Willebrand factor (vWF), and vascular endothelial cadherin (VE-cadherin). The results indicated that the KLD-V2 hydrogel significantly induced vasculogenesis in hMSC/HUVEC co-culture compared to KLD-V1, Biogelx and KLD because YIGSR in KLD-V2 promoted cell population and ECM secretion by the interaction with cells and increased vasculogenesis. Overall, the designed SAP hydrogel represents an effective scaffold for vascularization of tissue constructs with useful tissue engineering applications. © The Royal Society of Chemistry 2021.
