Browsing by Subject "osteosarcoma"

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    Delayed renal excretion of methotrexate after a severe anaphylactic reaction to methotrexate in a child with osteosarcoma
    (2009) Ozguven A.A.; Uysal K.; Gunes D.; Koroglu T.; Gurcu O.; Olgun N.
    Although methotrexate is an agent widely used in the practice of pediatric oncology, allergic reactions to methotrexate are most unusual. Most of these reactions typically occur after repeated administration. Here, we report a severe anaphylactoid reaction to the first dose of high-dose methotrexate infusion in a child with osteosarcoma who has also experienced a delayed excretion of methotrexate. Clinicians must be aware of the possibility of a systemic, near-fatal anaphylactic reactions with methotrexate and patients who experience severe anaphylactic reactions should be followed carefully because of the possibility of delayed methotrexate excretion. © 2009 Lippincott Williams & Wilkins Inc.
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    Primary tumors of the spine
    (Thieme Medical Publishers, Inc., 2014) Orguc S.; Arkun R.
    Spinal tumors consist of a large spectrum of various histologic entities. Multiple spinal lesions frequently represent known metastatic disease or lymphoproliferative disease. In solitary lesions primary neoplasms of the spine should be considered. Primary spinal tumors may arise from the spinal cord, the surrounding leptomeninges, or the extradural soft tissues and bony structures. A wide variety of benign neoplasms can involve the spine including enostosis, osteoid osteoma, osteoblastoma, aneurysmal bone cyst, giant cell tumor, and osteochondroma. Common malignant primary neoplasms are chordoma, chondrosarcoma, Ewing sarcoma or primitive neuroectodermal tumor, and osteosarcoma. Although plain radiographs may be useful to characterize some spinal lesions, magnetic resonance imaging is indispensable to determine the extension and the relationship with the spinal canal and nerve roots, and thus determine the plan of management. In this article we review the characteristic imaging features of extradural spinal lesions. Copyright © 2014 by Thieme Medical Publishers, Inc.
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    Synergistic role of three dimensional niche and hypoxia on conservation of cancer stem cell phenotype
    (Elsevier B.V., 2016) Gorgun C.; Ozturk S.; Gokalp S.; Vatansever S.; Gurhan S.I.D.; Urkmez A.S.
    Hypoxia is a pathalogical condition in which tissues are deprived of adequate oxygen supply. The hypoxia effect on tumors has a critically important role on maintenance of cancer stem cell phenotype. The aim of this study is to investigate the effects of hypoxia on cancer stem cells on three dimensional (3D) in vitro culture models. Osteosarcoma stem cells characterized by CD133 surface protein were isolated from osteosarcoma cell line (SaOS-2) by magnetic-activated cell sorting (MACS) technique. Isolated CD133+ and CD133− cells were cultivated under hypoxic (1% O2) and normoxic conditions (21% O2) for 3 days. For the 3D model, bacterial cellulose scaffold was used as the culture substrate. 3D morphologies of cells were examined by scanning electron microscopy (SEM); RT-PCR and immunocytochemistry staining were used to demonstrate conservation of the cancer stem cell phenotype in 3D environment under hypoxic conditions. Cell viability was shown by MTT assay on 3. and 7. culture days. This study is seen as an introduction to develop a 3D hypoxic cancer stem cell based tumor model to study CSC behavior and tumor genesis in vitro. © 2016
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    Development and characterization of cancer stem cell-based tumoroids as an osteosarcoma model
    (John Wiley and Sons Inc., 2020) Ozturk S.; Gorgun C.; Gokalp S.; Vatansever S.; Sendemir A.
    Three-dimensional (3D) cancer tumor models are becoming vital approaches for high-throughput drug screening, drug targeting, development of novel theranostic systems, and personalized medicine. Yet, it is becoming more evident that the tumor progression and metastasis is fueled by a subpopulation of stem-like cells within the tumor that are also called cancer stem cells (CSCs). This study aimed to develop a tumoroid model using CSCs. For this purpose CD133+ cells were isolated from SaOS-2 osteosarcoma cell line with magnetic-activated cell sorting. To evaluate tumoroid formation ability, the cells were incubated in different cell numbers in agar gels produced by 3D Petri Dish® method. Subsequently, CD133+ cells and CD133− cells were co-cultured to investigate CD133+ cell localization in tumoroids. The characterization of tumoroids was performed using Live&Dead staining, immunohistochemistry, and quantitative polymerase chain reaction analysis. The results showed that, CD133+, CD133− and SaOS-2 cells were all able to form 3D tumoroids regardless of the initial cell number, but, while 72 hr were needed for CD133+ cells to self-assemble, 24 hr were enough for CD133− and SaOS-2 cells. CD133+ cells were located within tumoroids randomly with high cell viability. Finally, when compared to two-dimensional (2D) cultures, there were 5.88, 4.14, 6.95, and 1.68-fold higher messenger RNA expressions for Sox2, OCT3/4, Nanog, and Nestin, respectively, in CD133+ cells that were cultured within 3D tumoroids, showing longer maintenance of stem cell phenotype in 3D, that can allow more relevant screening and targeting efficiency in pharmaceutical testing. It was concluded that CSC-based tumoroids are propitious as 3D tumor models to fill the gap between conventional 2D in vitro culture and in vivo animal experiments for cancer research. © 2020 Wiley Periodicals LLC
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    Pulmonary nodules in children; [Çocuklarda pulmoner nodüller]
    (Ankara University, 2022) Yüksel H.; Tongal S.N.
    Clinicians and radiologist nowadays frequently encounter pulmonary nodules in children, thanks to the widespread use of computed tomography (CT) thorax. Most pulmonary nodules are benign; however, a small number of pulmonary nodules indicate pulmonary malignancy in children, requiring prompt diagnosis and treatment. Incidentally diagnosed pulmonary nodules are common and naturally cause anxiety in families and in clinicians, leading to successive examinations. For this reason, the creation of algorithms for the diagnosis and follow-up of pulmonary nodules, and the definition of advanced imaging requirements will facilitate the management of these patients; early diagnosis and treatment will be provided in patients with malignant tumors, and unnecessary interventions will be minimized in patients with benign nodules. This review is designed to explore current information on nodule definition, diagnostic evaluation, and management in the pediatric age group based on previously obtained data. © 2022 by Tuberculosis and Thorax.
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    In vitro cytotoxicity of magnetic-fluorescent bioactive glasses on SaOS-2, MC3T3-E1, BJ fibroblast cells, their hemolytic activity, and sorafenib release behavior
    (Elsevier Ltd, 2024) Deliormanlı A.M.; Rahman B.; Atmaca H.
    In the study, the fabrication of superparamagnetic-fluorescent bioactive glasses in the form of the particle, nanofiber, and 3D scaffolds was performed by including maghemite (γ-Fe2O3) nanoparticles and photoluminescent rare earth element ions (Eu3+, Gd3+, and Yb3+) using sol-gel, electrospinning, and robocasting techniques, respectively. The in vitro cytotoxicity of the magnetic-fluorescent bioactive glasses on osteosarcoma SaOS-2, pre-osteoblast MC3T3-E1, and BJ fibroblast cells, as well as their hemolytic activity and sorafenib tosylate loading and release behavior, were investigated. The cytotoxicity of the bioactive glass samples was tested using the MTT assay. Additionally, the alkaline phosphatase activity of the studied glasses was examined as a function of time. The mineralization behavior of the pre-osteoblast cell-seeded glass samples was analyzed using Alizarin red S staining. Results revealed that the in vitro cytotoxicity of the studied bioactive glasses in the form of particles and nanofibers depended on the sample concentration, whereas in the case of the 3D scaffolds, no cytotoxic response was observed on the osteosarcoma, pre-osteoblast, and fibroblast cells. Similarly, particle and nanofiber-based glass samples induced dose-dependent hemolysis on red blood cells. Drug loading rates were much lower for the 3D scaffolds compared to the particle and nanofiber-based samples. Drug release rates ranged from 25 % to 90 %, depending on the bioactive glass morphology and the pH of the release medium. It was concluded that the studied bioactive glasses have the potential to be used in tissue engineering applications and cancer therapy. © 2024 Elsevier B.V.