Browsing by Author "Akgöl S."

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    Radiolabeling of new generation magnetic poly(HEMA-MAPA) nanoparticles with 131I and preliminary investigation of its radiopharmaceutical potential using albino Wistar rats
    (John Wiley and Sons Ltd, 2013) Avcibaşi U.; Demiroǧlu H.; Ediz M.; Akalin H.A.; Özçalişkan E.; Şenay H.; Türkcan C.; Özcan Y.; Akgöl S.; Avcibaşi N.
    In this study, N-methacryloyl-l-phenylalanine (MAPA) containing poly(2-hydroxyethylmethacrylate) (HEMA)-based magnetic poly(HEMA-MAPA) nanobeads [mag-poly(HEMA-MAPA)] were radiolabeled with 131I [ 131I-mag-poly(HEMA-MAPA)], and the radiopharmaceutical potential of 131I-mag-poly(HEMA-MAPA) was investigated. Quality control studies were carried out by radiochromatographic method to be sure that 131I binded to mag-poly(HEMA-MAPA) efficiently. In this sense, binding yield of 131I-mag-poly(HEMA-MAPA) was found to be about 95-100%. In addition to this, optimum radiodination conditions for 131I-mag-poly(HEMA- MAPA) were determined by thin-layer radiochromatography studies. In addition to thin-layer radiochromatography studies, lipophilicity (partition coefficient) and stability studies for 131I-mag-poly(HEMA-MAPA) were realized. It was determined that lipophilicities of mag-poly(HEMA-MAPA) and 131I-mag-poly(HEMA-MAPA) were 0.12 ± 0.01 and 1.79 ± 0.76 according to ACD/logP algorithm program, respectively. Stability of the radiolabeled compound was investigated in time intervals given as 0, 30, 60, 180, and 1440 min. It was found that 131I-mag-poly(HEMA-MAPA) existed as a stable complex in rat serum within 60 min. After that, biodistribution and scintigraphy studies were carried out by using albino Wistar rats. It was determined that the most important 131I activity uptake was observed in the breast, the ovary, and the pancreas. Scintigraphy studies well supported biodistribution results. Copyright © 2013 John Wiley & Sons, Ltd.
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    Synthesis and biodistribution of novel magnetic-poly(HEMA-APH) nanopolymer radiolabeled with iodine-131 and investigation its fate in vivo for cancer therapy
    (Kluwer Academic Publishers, 2013) Avcibaşi U.; Avcibaşi N.; Akalin H.A.; Ediz M.; Demiroǧlu H.; Gümüşer F.G.; Özçalişkan E.; Türkcan C.; Uygun D.A.; Akgöl S.
    Herein, we investigated the biological uptake, distribution, and radiopharmaceutical potential of a novel molecule based on 2-hydroxyethyl methacrylate (HEMA) and anilinephtalein (APH) in the metabolism of Albino Wistar rats. In order to achieve this, we synthesized APH using organic synthesis methods and copolymerized APH with HEMA using a common polymerization method, surfactant-free emulsion polymerization. In the presence of Fe3O 4 particles, we obtained a new generation magnetic-nano-scale polymer, magnetic-poly(HEMA-APH). This new molecule was chemically identified and approved by several characterization methods using Fourier transform infrared spectroscopy, scanning electron microscope, energy dispersive X-ray spectroscopy, electron spin resonance, atomic force microscope, and Zeta particle-size analysis. To evaluate the biological activity in live metabolism and anti-cancer potential of mag-poly(HEMA-APH), molecule was radioiodinated by a widely used labeling technique, iodogen method, with a gamma diffuser radionuclide, 131I. Thin-layer radiochromatography experiments demonstrated that 131I binded to nanopolymer with the labeling yield of 90 %. Lipophilicity and stability experiments were conducted to determine the condition of cold and labeled mag-poly(HEMA-APH) in rat blood and lipid medium. Results demonstrated that radioiodinated molecule stayed as an intact complex in rat metabolism for 24 h and experimental lipophilicity was determined as 0.12 ± 0.02. In vivo results obtained by imaging and biological distribution experiments indicated that mag-poly(HEMA-APH) labeled with 131I [131I-mag-poly(HEMA-APH)] highly incorporated into tissues of the uterus, the ovarian, the prostate, and the lungs in rat metabolism. Based on these results, it may be evaluated that novel mag-poly(HEMA-APH) molecule labeled with 131I is a compound which has a significant potential for being used as an anti-cancer agent. Certain results can only be obtained whether this molecule is applied to adenocarcinoma cell models and tumor-bearing animals. © 2013 Springer Science+Business Media Dordrecht.
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    Immobilization of amyloglucosidase onto macroporous cryogels for continuous glucose production from starch
    (Taylor and Francis Inc., 2015) Uygun M.; Akduman B.; Ergönül B.; Aktaş Uygun D.; Akgöl S.; Denizli A.
    Poly(methyl methacrylate-glycidyl methacrylate) [Poly(MMA-GMA)] cryogels were synthesized using monomers of methylmethacrylic acid and epoxy group bearing GMA via radical cryopolymerization technique. Synthesized cryogels were used for the immobilization of amyloglucosidase to the cryogel surface using epoxy chemistry. Characterizations of the free and immobilized amyloglucosidase were carried out by comparing the optimum and kinetic parameters of enzymes. For this, pH and temperature profiles of free and immobilized preparation were studied and, it was found that, optimum pH of enzyme was not change upon immobilization (pH 5.0), while optimum temperature of the enzyme shifted 10 °C to warmer region after immobilization (optimum temperatures for free and immobilized enzyme were 55 and 65 °C, respectively). Kinetic parameters of free and immobilized enzyme were also investigated and Km values of free and immobilized amyloglucosidase were found to be 2.743 and 0.865 mg/mL, respectively. Vmax of immobilized amyloglucosidase was found to be (0.496 mol/min) about four times less than that of free enzyme (2.020 mol/min). Storage and operational stabilities of immobilized amyloglucosidase were also studied and it was showed that immobilized preparation had much more stability than free preparation. In the present work, amyloglucosidase immobilized poly(MMA-GMA) cryogels were used for continuous glucose syrup production from starch for the first time. Efficiency of immobilized enzyme was investigated and released amount of glucose was found to be 2.54 mg/mL at the end of the 5 min of hydrolysis. The results indicate that the epoxy functionalized cryogels offer a good alternative for amyloglucosidase immobilization applications with increased operational and thermal stability, and reusability. Also, these cryogels can be used for immobilization of other industrially valuable enzymes beyond amyloglucosidase. © 2015 Taylor & Francis.
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    A novel radiolabeled graft polymer: Investigation of the radiopharmaceutical potential using Albino Wistar rats
    (Elsevier Ltd, 2019) Avcıbaşı U.; Ateş B.; Ünak P.; Gümüşer F.G.; Gülcemal S.; Ol K.K.; Akgöl S.; Tekin V.
    Fe3O4 magnetic graft-Lys-poly(HEMA) was synthesized, labeled with 99mTc for the first time and its radiopharmaceutical potential was investigated using animal models in this study. Quality control procedures were carried out using thin layer radiochromatography. The labeling yield of radiolabeled polymer was found to be about 100%. Then, stability and lipophilicity were determined. The lipophilicity of 99mTc labeled Fe3O4 graft-Lys-poly(HEMA) was found to be 3.77. The serum stability experiments demonstrated that approximately 100% of radiolabeled polymer existed as an intact complex in the rat serum within 240 min. Biodistribution of radiolabeled magnetic graft-Lys-poly(HEMA) was performed on female Albino Wistar rats by scintigraphy and biodistribution studies. High uptake was seen in the stomach, the pancreas, brain, ovarian, intestines and the breast. © 2019 Elsevier Ltd
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    Management of gynecological cancers in the COVID-19 era: A survey from Turkey
    (Galenos, 2020) Altın D.; Yalçın İ.; Khatib G.; Keleşoğlu M.D.; Akgöl S.; Önder A.B.; Kahramanoğlu İ.; Güvenal T.; Topuz S.; Demirkıran F.
    Objective: This study aimed to investigate how gynecologic oncologists modified their patient management during Coronavirus disease-2019 (COVID-19) in Turkey. Material and Methods: An online survey was sent to gynecologic oncology specialists and fellows in Turkey. It included management questions about strategies for newly diagnosed or recurrent endometrial, cervical, ovarian and vulvar cancer during the pandemic. Participants were asked if treatment of these cancers can be delayed or not and, if yes, the duration of delay. Results: 32.9% of surgeons prescribed oral or intrauterine progesterone for early stage, low-grade endometrial cancer. Conversely, 65.7% and 45.7% of the most surgeons did not change their management for early stage high-grade and advanced stage endometrial cancers respectively, as they perform surgery. 58% and 67.1% of the surgeons continued to prefer standard surgical treatment for microinvasive and early stage cervical cancers, respectively. Radiotherapy was preferred administered with hypofractionated doses for locally advanced cervical cancer (57.1%). While 67.1% of surgeons operated early stage ovarian cancer patients, 50% administered neoadjuvant chemotherapy (NACT) to all advanced stage ovarian cancers and 50% administered more cycles of NACT in preference to interval debulking surgery. 93.7% of the surgeons responded that treatment should not be delayed beyond eight weeks. Conclusion: Most Turkish gynecologic oncologists modified their management of gynecologic cancers due to the COVID-19 pandemic. While chemotherapy was preferred for ovarian cancer, postponement of the surgery, with or without non-surgical options, was considered for early stage, low-grade endometrial cancer. Treatment of gynecologic cancers should be decided on a case by case basis, taking into account local COVID-19 infection rates and availability of health facilities. Prognosis is also an important consideration if delay is contemplated. Standard treatment and normal time-frames should be used if possible. If not, a postponement for a maximum of eight weeks or referral to another center were acceptable alternatives. © 2020 by the Turkish-German Gynecological Education and Research Foundation.
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    Preparation of a 99mTc-labeled graft polymer and its in vitro and in vivo evaluation
    (Springer Science and Business Media B.V., 2021) Avcıbaşı U.; Türkyarar T.; Karadağ A.; Bakan B.; Yavaşoğlu N.Ü.K.; Kuşat K.; Akgöl S.; Gülcemal D.; Tekin V.; Müftüler F.Z.B.; Topal G.; Parlak Y.; Gümüşer F.G.
    The aim of this study is the synthesis of a novel 99mTc-labeld graft polymer and the biological evaluation of its in vitro and in vivo properties. To this end, a L-proline-graft-poly(HEMA) was prepared and labeled with 99mTc. The radiochemical yield of approximately the 99mTc-labeled compound amounted to 97 ± 2.3%. The cytotoxicity test revealed no cytotoxic effect after a 24- and 48-h incubation. The results of the hemolysis test showed that hemolysis was non-toxic with an effect level of less than 2%. Subsequently, the biodistribution in healthy rats was determined. High accumulation of the polymer was observed in the pancreas, thyroid and prostate. © 2021, Akadémiai Kiadó, Budapest, Hungary.