Browsing by Author "Celik, Serdar"

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Differences Between Patients With and Without Persistent PSA After Radical Prostatectomy in Clinically High-Risk And/Or Locally Advanced Prostate Cancer
(Galenos Publ House, 2025) Eker, Anıl; Degirmenci, Tansu; Bozkurt, İbrahim Halil; Celik, Serdar; Gunlusoy, Bulent; Çetin, Taha; Karaca, Berk
Objective: This study aimed to identify preoperative and postoperative factors associated with persistent prostate-specific antigen (PSA) following radical prostatectomy (RP) in patients with clinically high-risk and/or locally advanced prostate cancer. Understanding these factors can guide early postoperative management decisions, including adjuvant treatment strategies. Materials and Methods: A retrospective analysis was conducted on 183 patients who underwent RP for locally advanced prostate cancer between 2009 and 2023. Patients were divided into two groups: those with persistent PSA at 1 month postoperatively (group 2, n=43), and those without (group 1, n=140). Preoperative and postoperative variables, including PSA levels, clinical stage, biopsy grade group, tumor volume, and pathological findings, were compared between groups. Results: Patients in group 2 had significantly higher preoperative PSA levels (24.6±19 ng/mL vs. 15±15.5 ng/mL, p<0.001), advanced clinical stage (≥T2B: 52.6% vs. 32.1%, p=0.032), and higher percentage of positive biopsy cores (p=0.011). Postoperative findings demonstrated a higher tumor volume (20.2±14.1 cc vs. 10.7±10.5 cc, p=0.002), tumor density (p=0.005), and positive surgical margins (86% vs. 70%, p=0.025) in group 2. Patients in group 2 had higher rates of lymph node dissection, adjuvant therapy, and early salvage radiotherapy. Conclusion: Preoperative PSA levels, biopsy grade group, positive surgical margins, and advanced pathological stage are critical predictors of persistent PSA after RP. Early identification of high-risk patients enables personalized management plans, including timely initiation of adjuvant therapies, to improve outcomes. Further prospective studies are needed to refine risk stratification models and personalize treatment strategies.
Citation - WoS: 14
Citation - Scopus: 17
Energy Savings and Economic Impact of Green Roofs: a Pilot Study
(Routledge Journals, Taylor & Francis Ltd, 2018) Celik, Serdar; Oğuş Binatlı, Ayla
This study focuses on the energy savings and economic impact of green roof systems applied to Central Bodrum, a district in southwestern Turkey. Energy savings of the buildings were evaluated based on the added thermal resistance on the roofs and corresponding heat transmission through the roofs. Four different scenarios, two without green financing and two with green consumer loans for retrofitting financed by the central government via the state-owned banks, were studied. The economic impact of this activity on the economy is estimated based on sectoral employment multipliers for a period of 10years. Based on the scenario analysis and the priorities of the Turkish economy, given the employment benefits and energy savings which would reduce the energy demand in the area in the peak season, we propose that the government implements green consumer loans for retrofitting through the state-owned banks.
Citation - WoS: 6
The Role of Cancer Stem Cells in Immunotherapy for Bladder Cancer: an in Vitro Study
(Elsevier Science Inc, 2020) Ozcan, Yegane; Caglar, Fulya; Celik, Serdar; Demir, Ayse Banu; Ercetin, Ayse Pinar; Altun, Zekiye; Aktas, Safiye
Objective: Bladder cancer is characterized by frequent recurrence and progression. CD44+ cancer stem cells (CSCs) might be one of the main reasons for recurrence. Although Bacillus Calmette Guerin (BCG) has become a gold standard immunotherapy, after treatment recurrence frequently occur. Based on this knowledge, the aim of this study was to evaluate the changes in cytokine and chemokine expressions in bladder cancer and CSCs cultures in vitro with BCG only and in combination with IL2 and lymphocyte (MNCs) applications. Material and methods: In this study, 3 cell lines of human bladder cancer cells with different characteristics (T24, 5637, and JMSU-1) and CD44+ bladder CSCs isolated by magnetic bead isolation (Miltenyl Magtech) were used. Bladder cancer cell lines and bladder CSCs in complete medium were cultured under humidified conditions of 37 degrees C temperature in 5% CO2. BCG only and its combination with IL2 and MNCs were applied to bladder cancer cell lines and bladder CSCs for 24, 48, and 72 hours. Annexin V-PI was used to detect the percentages of apoptotic and necrotic cells in treatment groups and control groups. After treatments, total RNAs were isolated and converted to cDNA for each group and controls. Quantitative fold changes in terms of gene expression were measured by RT2 PCR array and fold changes for expression levels of genes were compared among groups. Eighty-four genes were analyzed in standard array of chemokines and cytokines (Biorad). Results: BCG treatment with 7.32 mu g/ml dose alone and in combination with IL2 (1000 IU/ml) and MNCs (1000 cells/ml) were found to be most effective on bladder cancer cells. When BCG and its combinations were applied to CSCs of the 3 cell lines, BCG treatment showed cytotoxic effect on CSCs as well as cancer cells. CSCs of 3 cell lines over expressed CXCL5, CCL8, CNTF, and CSF2 compared with cancer cells. Cancer cells over expressed IL6, TNSFF11, FASLG, and CXCL9 compared with CSCs. In all 3 cell lines, BCG application increased expression of CXCL5 and LTB and also decreased CCL20 and IL6. When BCG was combined with IL2 and MNCs, CXCL10, CXCL5, and IFNG were increased and CXCL12, IL6, and TNSF11 were decreased. BCG treatment of CSCs caused increases in ADIPOQ, CXCL10, and XCL1 and a decrease in CCL8. When IL2 and MNCs were combined with BCG, the expression of many cytokines and chemokines decreased. Conclusion: BCG treatment changes the expression of many cytokines and chemokines in bladder cancer. The expression differs in 3 different cell lines and their CSCs. Immune modulation of each case differs from each other. The effectivity of BCG-based immunotherapy in bladder cancer on CSCs might decrease in combination with IL2. Our results indicate that recurrence after BCG treatment for bladder cancer may not occur mainly based on the CSCs hypothesis considering bladder cancer occurs at different loci of surface epithelium. (C) 2020 Elsevier Inc. All rights reserved.