Browsing by Author "Cengiz M."

Now showing 1 - 9 of 9
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    Practice patterns for oropharyngeal cancer in radiation oncology centers of Turkey
    (Il Pensiero Scientifico Editore s.r.l., 2014) Karakoyun-Celik O.; Altun M.; Olmezoglu A.; Büyükpolat M.Y.; Ozkok S.; Akmansu M.; Cengiz M.; Onal C.; Dizman A.; Esassolak M.
    Aims and background. The aim of the study was to review the current clinical practices of radiation oncologists involved in the treatment of oropharyngeal cancer. Methods and study design. The daily practices of radiation oncology centers for patients diagnosed with oropharyngeal cancer in 2010 were evaluated by a two-part questionnaire that separately assessed the information of the participating center and the charts of the treated patients. Results. A total of 22 centers participated in the study, and 105 oropharyngeal cancer patients reported for our review. The use of positron emission tomography was a common practice in staging and radiotherapy planning. Multidisciplinary head and neck cancer clinics were available in 14 (64%) centers and were absent in 8 centers. Thirty-six of the 105 patients were not evaluated by a multidisciplinary clinic before the initiation of therapy, and adjuvant radiotherapy administration was found to be higher in this group. Percutaneous endoscopic gastrostomy tube placement was not a routine practice in any of the centers. Seventy-five patients received chemotherapy - 46 concurrently with radiotherapy and 29 as induction chemotherapy. Two centers administered conventional radiotherapy alone, 20 centers conformal radiotherapy, and 7 centers were able to provide intensity-modulated radiotherapy. Conclusions. Across all the centers there were small differences in the pretreatment evaluation of patients with oropharyngeal cancer. The greatest difference was in the technical delivery of radiation, with most of the centers using conformal radiotherapy despite the increasing availability of intensity-modulated radiotherapy. The use of chemotherapy has more readily adopted the current international standards in the treatment of oropharyngeal cancer. Copyright - Il Pensiero Scientifico Editore.
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    Development of an interactive game-based learning environment to teach data mining
    (Tempus Publications, 2017) Cengiz M.; Birant K.U.; Yildirim P.; Birant D.
    Game-based learning has become a popular topic in all levels of education. A number of computer games have been developed to teach different subjects such as mathematics, English language, medicine, and music. This paper presents the first study that proposes the development of edutainment games to teach data mining techniques with the scope of gamebased learning. The aim ofthis study is to provide an environment that is both fun and enables the achievementof learning goals in data mining training in computer engineering. An escape game called Mine4Escape, which consists of different rooms to teach different data mining techniques (classification and association rule mining), has been developed for individuals at the undergraduate and post-graduate levels. The advantages of the proposed approach are discussed in comparison with traditional data mining training. In addition, this paper describes a dynamic scoring system designed for game-based learning. Finally, an experimental study was carried out to evaluate the performance of our learning environment by analyzing feedback received from a test group consisting of 39 undergraduate and graduate students in computer engineering. Thefindings from thequestionnaire show that it is possible to enhance knowledge acquisition about data mining via the game-based approach. However, the degree of learning interest and information acceptance changes according to students' age, gender, educational level, and game habits. © 2017 TEMPUS Publications.
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    Onosma heterophyllum: Phenolic composition, enzyme inhibitory and antioxidant activities
    (Elsevier B.V., 2018) Ozer M.S.; Kirkan B.; Sarikurkcu C.; Cengiz M.; Ceylan O.; Atılgan N.; Tepe B.
    Onosma species have frequently been used for their colouring and dyeing properties in foods and medicinal preparations. The antioxidant and enzyme inhibitory activities of the ethyl acetate, methanol and water extracts of Onosma heterophyllum (Griseb.) are described. Phytochemical compositions of these extracts were also determined. The water extract showed not only remarkable antioxidant activity in all assays but also considerable inhibitory activity on tyrosinase and α-glucosidase (112.44 μmol KAEs/g dry plant and 984.36 μmol ACEs/g dry plant, respectively). The methanol extract exhibited the highest inhibitory activity on acetylcholinesterase (AChE) and α-amylase (79.18 μmol GALAEs/g dry plant and 10.42 μmol ACEs/g dry plant, respectively). Chromatographic analyses revealed that the water extract was found to be rich in phenolic and flavonoid contents. On the basis of the correlation coefficients calculated separately for all experimental parameter pairs, protocatechuic acid, p-hydroxybenzoic acid, syringic acid, p-coumaric acid and luteolin were found to be highly in correlation with the antioxidant and enzyme inhibitory activities. This study demonstrates that O. heterophyllum, contained in food preparations with various purposes for many years, could be used for the treatment of diabetes as well as its skin whitening effect. © 2017 Elsevier B.V.
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    Chemical characterization and biological activity of Onosma gigantea extracts
    (Elsevier B.V., 2018) Sarikurkcu C.; Kirkan B.; Ozer M.S.; Ceylan O.; Atilgan N.; Cengiz M.; Tepe B.
    Onosma species have traditionally been used as laxative and anthelmintic agents as well as their uses in eye, blood diseases, bronchitis, abdominal pain, strangury, thirst, itch, leucoderma, fever, wounds, burns, piles, and urinary calculi. This study examines the investigation of biological activities of ethyl acetate, methanolic, and aqueous extracts from Onosma gigantea Lam. The extracts were evaluated for the antioxidant and enzyme inhibitory activities. Phenolic compounds in the extracts were also detected by RP-HPLC-DAD. The aqueous extract showed remarkable antioxidant activity in phosphomolybdenum [134.31 μmol trolox equivalents (TEs)/g air dry matter (adm)], chelating effect [32.97 μmol ethylenediaminetetraacetic acid (disodium salt) equivalents (EDTAEs)/g adm], radical scavenging [on DPPH (32.14 μmol TEs/g adm) and ABTS (58.68 μmol TEs/g adm)], and reducing power [CUPRAC (50.23 μmol TEs/g adm) and FRAP (40.96 μmol TEs/g adm)] assays. The aqueous extract also exhibited considerable inhibitory activity of tyrosinase (10.48 μmol kojic acid equivalents/g adm) and α-glucosidase [1320.53 μmol acarbose equivalents (ACEs)/g adm]. It has been determined that the methanolic extract showed significant AChE (31.57 μmol galanthamine equivalents (GALAEs)/g adm) and α-amylase (6.75 μmol ACEs/g adm) inhibitory activity. The ethyl acetate, which contains low polarity compounds, showed the highest BChE inhibitory activity (6.87 μmol GALAEs/g adm). In general, it is found that there is a positive correlation between the phytochemical contents of the extracts and their biological activities. The results indicate that O. gigantea extracts could be considered as a novel source of bioactive agents with functional connections. © 2018 Elsevier B.V.
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    Can the stalks of Papaver somniferum L. be an alternative source of bioactive components?
    (Elsevier B.V., 2018) Kirkan B.; Ozer M.S.; Sarikurkcu C.; Copuroglu M.; Cengiz M.; Tepe B.
    Alternative raw materials for designing novel products are gaining interest in the scientific area. The aim of this study is to investigate the antioxidant and enzyme inhibitory activities of the extracts obtained from Papaver somniferum L. stalks as well as the determination of chemical composition. Antioxidant capacity was tested by using different chemical methods including radical scavenging, reductive effect, phosphomolybdenum and metal chelating assays. Enzyme inhibitory effect was investigated against cholinesterase, tyrosinase, α-amylase and α-glucosidase. To detect chemical composition, phenolic profile was determined by high performance liquid chromatography (HPLC) as well as total contents of the phytochemicals. The aqueous extract was found to contain high amount of phenolics and flavonoids [9.87 μmol gallic acid equivalents (GAEs)/g dry plant (dp) and 0.09 μmol rutin equivalents (REs)/g dp, respectively]. The methanol and aqueous extracts were also found to contain considerable amounts of (−)-epicatechin and syringic acid. Antioxidant activity tests were resulted in the superiority of the methanol extract. The extracts did not show inhibitory activity on cholinesterases and tyrosinase. Inhibitory activity of the aqueous extract on α-amylase and α-glucosidase were found to be 9.85 and 78.64 μmol acarbose equivalents (ACEs)/g dp, respectively. As a result, P. somniferum stalks, one of the major by-products of poppy cultivation, can be used as the alternative source of antioxidant and enzyme inhibitory compounds in food and medical industries. © 2018 Elsevier B.V.
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    Phenolic profile, antioxidant and enzyme inhibitory potential of Onosma tauricum var. tauricum
    (Elsevier B.V., 2018) Kirkan B.; Sarikurkcu C.; Ozer M.S.; Cengiz M.; Atılgan N.; Ceylan O.; Tepe B.
    This study focused on phytochemical characterization and biological evaluation, both antioxidant and enzymatic inhibition, of ethyl acetate (OTT-EtOAc), methanol (OTT-MeOH), and water (OTT-W) extracts from Onosma tauricum var. tauricum aerial parts. The OTT-W extract was found to be the richest one in terms of its phenolic and flavonoid contents. Amounts of the phenolic and flavonoid compounds were determined as 40.88 μmol GAEs/g and 7.40 μmol REs/g dry plant (dp), respectively. The OTT-MeOH and OTT-W extracts were also found to contain significant amounts of chlorogenic acid, rosmarinic acid, p-hydroxybenzoic acid, caffeic acid, rutin, p-coumaric acid, trans-cinnamic acid, luteolin, and apigenin. The OTT-W extract showed remarkable antioxidant activity in phosphomolybdenum, ferrous ion chelating, reducing power, and radical scavenging assays. The OTT-MeOH extract exhibited inhibitory activity on acetylcholinesterase (AChE) (54.62 μmol GALAEs/g dp), while the extracts remained almost inactive on butyrylcholinesterase (BChE). The OTT-W extract also exhibited inhibitory activity on tyrosinase (90.66 μmol KAEs/g dp) and α-glucosidase (2258.87 μmol ACEs/g dp). The results suggest that especially the OTT-MeOH and OTT-W extracts can be used as a source of alternative natural products in the treatment of diseases caused by the enzymes evaluated here. © 2018 Elsevier B.V.
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    Calamintha incana: Essential oil composition and biological activity
    (Elsevier B.V., 2019) Popović-Djordjević J.; Cengiz M.; Ozer M.S.; Sarikurkcu C.
    The chemical composition of the essential oils (EO) isolated aerial parts of Calamintha incana (Sm.) Boiss. from Turkey was characterized by GC-FID and GC–MS analysis. The oxygenated monoterpenes trans-piperitone oxide (41.37%), piperitenone oxide (34.47%), piperitenone (6.67%), and monoterpene phenol thymol (3.37%) were found to be the major constituents of the essential oils of C. incana. The results of the antioxidant activity in phosphomolybdenum, radical scavenging (DPPH and ABTS) and reducing power activity (CUPRAC and FRAP) as well as metal chelating effects (ferrous ion chelating) showed that EO was the most potent in ABTS (129.58 ± 2.21 mg TEs/g oil) and CUPRAC and FRAP (51.14 ± 0.05 and 53.63 ± 0.10 mg TEs/g, respectively) assays. In enzymes inhibitory activity assays of EO, the best result was achieved for tyrosinase (2.10 ± 0.30 mg KAEs/g oil). The results suggest that EO might be considered as a potential source of bioactive agents to be used in food and pharmacological industries. © 2018 Elsevier B.V.
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    Multi-institutional analysis of cervical esophageal carcinoma patients treated with definitive chemoradiotherapy: TROD 01-005 study
    (Tech Science Press, 2023) Guler O.C.; Oymak E.; Yazici G.; Akagunduz O.O.; Cetinayak O.; Erpolat P.; Aksoy A.; Duzova M.; Yildirim B.A.; Kurt M.; Canyilmaz E.; Yavas G.; Akyurek S.; Oksuz D.C.; Saglam E.K.; Celik O.K.; Ozyar E.; Cengiz M.; Onal C.
    The aim of this study was to examine the prognostic factors and treatment outcomes of cervical esophageal carcinoma (CEC) patients who underwent definitive chemoradiotherapy (CRT). The clinical data of 175 biopsy-confirmed CEC patients treated with definitive CRT between April 2005 and September 2021 were retrospectively analyzed. The prognostic factors predicting overall survival (OS), progression-free survival (PFS), and local recurrence-free survival (LRFS) were assessed in uni-and multivariable analyses. The median age of the entire cohort was 56 years (range: 26–87 years). All patients received definitive radiotherapy with a median total dose of 60 Gy, and 52% of the patients received cisplatin-based concurrent chemotherapy. The 2-year OS, PFS, and LRFS rates were 58.8%, 46.9%, and 52.4%, respectively, with a median follow-up duration of 41.6 months. Patients’ performance status, clinical nodal stage, tumor size, and treatment response were significant prognostic factors for OS, PFS, and LRFS in univariate analysis. Non-complete treatment response was an independent predictor for poor OS (HR = 4.41, 95% CI, 2.78–7.00, p < 0.001) and PFS (HR = 4.28, 95% CI, 2.79–6.58, p < 0.001), whereas poor performance score was a predictor for worse LRFS (HR = 1.83, 95% CI, 1.12–2.98, p = 0.02) in multivariable analysis. Fifty-two patients (29.7%) experienced grade II or higher toxicity. In this multicenter study, we demonstrated that definitive CRT is a safe and effective treatment for patients with CEC. Higher radiation doses were found to have no effect on treatment outcomes, but a better response to treatment and a better patient performance status did. © 2023, Tech Science Press. All rights reserved.
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    Efficacy of first-line CDK 4-6 inhibitors in premenopausal patients with metastatic breast cancer and the effect of dose reduction due to treatment-related neutropenia on efficacy: a Turkish Oncology Group (TOG) study
    (Taylor and Francis Ltd., 2025) Yildirim H.C.; Kapar C.; Koksal B.; Seyyar M.; Sanci P.C.; Guliyev M.; Perkin P.; Buyukkor M.; Yaslikaya S.; Majidova N.; Keskinkilic M.; Ozaskin D.; Avci T.; Gunes T.K.; Arcagok M.; Topal A.; Keskin G.S.Y.; Kavgaci G.; Yildirim N.; Celayir O.M.; Avci N.; Aslan F.; Alkan A.; Erciyestepe M.; Cengiz M.; Pehlivan M.; Gulmez A.; Beypinar I.; Basoglu Tuylu T.; Kayikcioglu E.; Chalabiyev E.; Turhal S.; Guzel H.G.; Ayas E.; Sahbazlar M.; Dulgar O.; Demir H.; Yavuzsen T.; Bayoglu V.; Kivrak Salim D.; Ozturk B.; Ozdemir F.; Kara O.; Oksuzoglu B.; Bal O.; Demirci N.S.; Yilmaz M.; Cabuk D.; Aksoy S.
    The only phase 3 study on the effectiveness of CDK 4-6 inhibitors in first-line treatment in premenopausal patients with hormone receptor (HR) positive, HER2 negative metastatic breast cancer is the MONALEESA-7 study, and data on the effectiveness of palbociclib is limited. Data are also limited regarding the effectiveness of CDK 4-6 inhibitors in patients whose dose was reduced due to neutropenia, the most common side effect of CDK 4-6 inhibitors. In our study, we aimed to evaluate the effectiveness of palbociclib and ribociclib in first-line treatment in patients with premenopausal metastatic breast cancer and the effect of dose reduction due to neutropenia on progression-free survival. Our study is a multicenter, retrospective study, and factors affecting progression-free survival (PFS) were examined in patients diagnosed with metastatic premenopausal breast cancer from 29 different centers and receiving combination therapy containing palbociclib or ribociclib in the metastatic stage. 319 patients were included in the study. The mPFS for patients treated with palbociclib was 26.83 months, and for those receiving ribociclib, the mPFS was 29.86 months (p = 0.924). mPFS was 32.00 months in patients who received a reduced dose, and mPFS was 25.96 months in patients who could take the initial dose, and there was no statistical difference (p = 0.238). Liver metastasis, using a fulvestrant together with a CDK 4-6 inhibitor, ECOG PS 1 was found to be a negative prognostic factor. No new adverse events were observed. In our study, we found PFS over 27 months in patients diagnosed with premenopausal breast cancer with CDK 4-6 inhibitors used in first-line treatment, similar to post-menopausal patients. We did not detect any difference between the effectiveness of the two CDK 4-6 inhibitors, and we showed that there was no decrease in the effectiveness of the CDK 4-6 inhibitor in patients whose dose was reduced due to neutropenia. © 2024 Edizioni Scientifiche per l'Informazione su Farmaci e Terapia (Italian Society of Chemotherapy).