Browsing by Author "Ozdemir, O"
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Item Effect of drop weight impact on the torsional-loading behavior of filament wound and prepreg-wrapped composite tubesSoykok, IF; Tas, H; Ozdemir, O; Kandas, HThis article presents an experimental study on the torsional behavior of composite tubes subjected to impact loadings. Four types of composite tubes with the winding angle of 30 degrees, 45 degrees, 60 degrees, and 75 degrees ([+/- 30](FW), [+/- 45](FW), [+/- 60](FW), and [+/- 75](FW)) were produced with the filament winding method. Besides, a [0,90](PP) composite tube was manufactured with the prepreg wrapping technique. After the composite tubes were impacted at 2.5 J, 5.0 J, and 7.5 J, non-impacted and impacted composite tubes were tested under torsional loading. Contact force-deformation curves of impacted tubes are presented. Torsional moment-twist angle relations for both impacted and non-impacted composite tubes were obtained. In addition, front view and side view of the impacted zone of composite tubes are given. The results showed that sample [+/- 60](FW) had the best impact performance with regard to absorbed energy. The impacted samples of [+/- 60](FW) and [+/- 75](FW) had the lowest torsional strength for each energy level.Item Bilateral fracture of the pisiform boneOzalp, T; Kurt, C; Coskunol, E; Ozdemir, O; Begue, TFracture of the pisiform bone is exceptional compared with the other carpal bones. Such lesions may be missed in the emergency room because of the complex anatomy of the carpal region. The usual circumstances leading to fracture of the pisiform bone include fall with reception on the hyperextencled wrist, traffic accidents, and blunt trauma. The purpose of this work was to present a case of bilateral fracture of the pisiform bones. A 34-year-old woman presented with pain along the ulnar borders of both wrists after a fall. The mechanism of fracture was direct trauma on both hands after reception in radial inclination. The diagnosis was established late and conservative treatment was applied. After simple immobilization, the clinical and functional outcome was excellent. The anatomic position of the pisiform bone exposes it to direct trauma. Late diagnosis can favor osteoarthritic sequelae involving the pisotriquetral joint.Item Giant-cell tumor of the handOzalp, T; Yercan, H; Oku, G; Ozdemir, O; Coskunol, E; Bégué, T; Calli, IPurpose of the study Giant-cell bone tumors are benign but have great potential for recurrence. Frequently observed in epiphyseal areas of tubular bones, these tumors are rarely found in hand localizations. We examined the characteristic features of giant-cell tumors of the hand and analyzed the pertinence of surgical treatment. We noted complications, consequences of recurrence and later operations on the same tumor site in five cases. Case reports Five patients treated between 1973 and 2000 for giant-cell tumors involving the hand bones were reviewed retrospectively, Mean age was 41.6 years and mean follow-up was 7.8 years. The surgical procedure was curettage for two, curettage with bone graft for two and amputation for one. The Enneking score was noted. Results Pain was the main symptom, with local swelling in several cases. At 7.8 years follow-up recurrence was noted for four of the five tumors. Two patients were treated for a second recurrence. Amputation of the forearm was required for one recurrence affecting soft tissue. Mean time between two consecutive recurrences was three months. In all six episodes of recurrent tumor were treated. These five patients had a total of ten operations. There were no cases of metastasis nor multicentric foci. Discussion Treatment of giant-cell tumors involving the hand bones is designed to eradicate the tumor and also protect hand function while keeping in mind the aggressive nature of these benign tumors. Surgical alternatives for radical treatment can include wide resection, resection of the ray and amputation.Item The endemic RTL80V/I and RTM204V/I YMDD mutation profiles in a case of chronic hepatitis BOzdemir, O; Alagözlu, H; Timuçin, M; Ozdemir, S; Korkmaz, M; Koksal, B; Ozen, OItem Caffeine use in preterm neonates: national insights into Turkish NICU practicesUnal, S; Beken, S; Ince, DA; Turan, O; Toygar, AK; Ecevit, A; Akcan, AB; Akin, MA; Aktas, S; Ciftdemir, NA; Altuncu, E; Altunhan, H; Arcagok, BC; Armangil, D; Ozer, EA; Aydin, B; Bezirganoglu, H; Bilgin, L; Calisici, E; Calkavur, S; Celik, K; Celik, Y; Cetinkaya, B; Cetinkaya, M; Demirel, A; Demirel, G; Dogan, NN; Dogan, P; Durukan, M; Engur, D; Ercan, TE; Gokmen, Z; Varal, IG; Gulasi, S; Gunlemez, A; Gursoy, T; Toptan, HH; Hamitoglu, S; Isleyen, F; Iyigun, I; Kader, S; Kahvecioglu, D; Kayki, G; Kostu, M; Kurnaz, D; Mammadaliyev, T; Akin, IM; Narli, N; Okulu, E; Okur, N; Olukman, O; Ovali, F; Ozcan, B; Ozdemir, A; Ozdemir, O; Ozkan, H; Sandal, G; Sarici, D; Sivrikaya, C; Bilgin, BS; Sundus, S; Onay, OS; Simsek, H; Tandircioglu, UA; Tanriverdi, S; Tekgunduz, KS; Terek, D; Tunc, G; Tunc, T; Tutak, E; Tufekcioglu, E; Erdogan, FT; Ulu, E; Isik, DU; Uras, N; Uslu, SI; Unal, I; Yilmaz, FH; Moniri, AObjective: Caffeine is a proven medication used for the prevention and treatment of apnea in premature infants, offering both short- and long-term benefits. International guidelines provide a range of recommendations regarding the preterm population eligible for caffeine prophylaxis, including the timing, dosage, and duration of treatment. Our national guidelines, published prior to the most recent updates of the international guidelines, recommend the use of caffeine citrate starting from the first day after delivery for preterm infants with a gestational age of <28 weeks. For infants up to 32 weeks, if positive pressure ventilation is required, the decision should be made on an individual basis. This study aims to describe the variability in caffeine usage across neonatal intensive care units in our country. Methods: An online survey was sent to neonatologist who are members of the Turkish Neonatology Society to describe the variability in caffeine usage in neonatal intensive care units in our country. Results: We collected responses from 74 units. Prophylactic caffeine usage was observed as; GA <= 27(6/7): 98.6%, GA 28(0/7)-28(6/7): 89.0%, GA 29(0/7)-29(6/7): 75.3%, GA 30(0/7)-31(6/7): 53.4%. 62.2% of units reported administering loading dose within the first two hours. The initial maintenance dose was 5 mg/kg in 64.8% of units, 10 mg/kg in 32.4% of units, and intermediate dose in 5.3% of units. 47.3% of units reported no routine dose adjustment. The postmenstrual age that caffeine treatment was stopped was found to be 34 (min-max; 32-36) weeks for infants without apnea and respiratory support, 36 (min-max; 34-52) weeks for infants without apnea but any respiratory support. The time to discharge after treatment cessation was found as; 1-4 days: 37.8%, 5-7 days: 68.9%. Among the 56 units with multiple responsible physicians, 32.1% reported intra-unit variations. Conclusion: The significant differences in caffeine usage characteristics between and within units highlight the need for clear recommendations provided by standardized guidelines.Item Food-induced anaphylaxis in early childhood and factors associated with its severityAydogan, M; Topal, E; Yakici, N; Acar, HC; Demirkale, ZH; Arga, M; Uysal, P; Aydemir, S; Simsek, IE; Tamay, Z; Cekic, S; Cavkaytar, O; Kaplan, F; Kiykim, A; Cogurlu, MT; Süleyman, A; Yücel, E; Akkelle, E; Hancioglu, G; Yasar, A; Tuncel, T; Nacaroglu, HT; Aydogmus, C; Güler, N; Cokugras, H; Sapan, N; Yüksel, H; Sancak, R; Erdogan, MS; Ozdemir, O; Ozdemir, C; Orhan, FBackground: Several factors that increase the risk of severe food-induced anaphylaxis have been identified. Objective: We aimed to determine the demographic, etiologic, and clinical features of food-induced anaphylaxis in early childhood and also any other factors associated with severe anaphylaxis. Methods: We carried out a medical chart review of anaphylaxis cases from 16 pediatric allergy and immunology centers in Turkey. Results: The data of 227 patients with 266 food-induced anaphylaxis episodes were included in the study. The median (inter quartile range) age of the first anaphylaxis episode was 9 months (6-18 months); 160 of these patients were boys (70.5%). The anaphylaxis episodes were mild in 75 cases (28.2%), moderate in 154 cases (57.9%), and severe in 37 cases (13.9%). The most frequent food allergens involved were cow's milk (47.4%), nuts (16.7%), and hen's egg (15.8%). Epinephrine was administered in only 98 (36.8%) of these anaphylaxis episodes. A logistic regression analysis revealed two statistically significant factors that were independently associated with severe anaphylaxis: the presence of angioedema and hoarseness during the anaphylactic episode. Urticaria was observed less frequently in patients who developed hypotension. In addition, confusion and syncope were associated with 25.9- and 44.6-fold increases, respectively, in the risk of concomitant hypotension. Conclusion: Cow's milk, nuts, and hen's egg caused the majority of mild and moderate-to-severe anaphylaxis episodes. The presence of angioedema and hoarseness in any patient who presents with a history of food-induced anaphylaxis should alert clinicians that the reaction may be severe. In addition, the presence of confusion, syncope, or stridor probably indicates concomitant hypotension.Item A retrospective analysis on first-line bevacizumab, cetuximab, and panitumumab-containing regimens in patients with RAS-wild metastatic colorectal cancer: A Collaborative Study by Turkish Oncology Group (TOG)Degirmencioglu, S; Tanriverdi, O; Menekse, S; Dogan, M; Hacioglu, B; Oktay, E; Erdem, D; Arpaci, E; Uluc, BO; Turhal, S; Yilmaz, M; Pilanci, KN; Sakin, A; Araz, M; Cokmert, S; Ozdemir, O; Sen, E; Nayir, EPurpose: To compare the efficacy and adverse effect profiles of the first-line treatment of patients with KRAS wild type metastatic colorectal cancer (CRC) in Turkey who were treated based on regimens including bevacizumab, cetuximab and panitumumab. Methods: This retrospective multicenter observational study involved a total of 238 patients who received chemotherapy in combination with either bevacizumab or cetuximab or panitumumab as first-line therapy for KRAS wild-type metastatic colorectal cancer. Patients with full medical records having pathological diagnosis of CRC adenocarcinoma were included in the study. The demographic, laboratory, histopathological and clinical characteristics of the patients were determined, and three groups were compared based on the study variables. Results: The mean age of the entire sample (n=238) was 58 +/- 11 years, 64% of which were male. The most frequent tumor localization was the rectum (37%) and G2 was the most common tumor grade (59.7%). About 63% of the patients had metastatic disease at diagnosis, with the most common site of metastasis being lung (14.7%) and liver (52.5%). Overall survival (OS) was 63.9%, while 1-, 3- and 5-year survival rates were 91.7, 56.6 and 36.9%, respectively. The expected mean survival was 49.1 months (95% CI, 42.9-55.3). The 1-, 3- and 5-year progression-free survival (PFS) rates following first-line treatment were 65.3, 26.1 and 5.6%, respectively, while disease free survival (DFS) in patients without metastasis at diagnosis was 68.5%. An analysis carried out disregarding which treatment the patients received (FOLFOX or FOLFIRI) revealed that a panitumumab-containing combination resulted in poorer prognosis compared to bevacizumab or cetuximab-containing combination (p <0.001). With regard to the adverse effect profile, the most common adverse effects were neuropathy and neutropenia in patients receiving FOLFOX-bevacizumab; neutropenia and perforation in patients receiving FOLFIRI-bevacizumab; rash and pustular infection in patients receiving FOLFIRI-cetuximab; and diarrhea in patients who received FOLFIRI-panitumumab combination. Conclusion: is the first multicenter study performed in Turkey evaluating the response to treatment and adverse effects in patients with KRAS wild-type metastatic colorectal cancer.Item Programmed cell death ligand-1 expression in gastroentero-pancreatic neuroendocrine tumorsOktay, E; Yalcin, GD; Ekmekci, S; Kahraman, DS; Yalcin, A; Degirmenci, M; Dirican, A; Altin, Z; Ozdemir, O; Surmeli, Z; Diniz, G; Ayhan, S; Bulut, G; Erdogan, A; Uslu, RPurpose: Gastroenteropancreatic tumors (GEPNETs) is a heterogeneous disease with variable clinical course. While promising therapeutic options exist for other adult cancers, there are no new molecular-based treatments developed for GEPNETs. One of the main targets of cancer immunotherapy is the Programmed Cell Death Ligand-1 (PD-L1) pathway. Our purpose was to investigate the profile of PD-L1 expression in different organs of GEPNETs and compare the conventional immunohistochemistry (IHC) with the RNA expression analysis via real time polymerase chain reaction (RT-PCR) in order to determine which patients might be appropriate for immune check point-targeted therapy. Methods: A total of 59 surgically or endoscopically resected GEPNET tissues were retrospectively collected. The expression of PD-LI and mRNA was evaluated with IHC. Results: The expression of PD-L1 was significantly associated with the high-grade classification (p=0.012). PD-LI mRNA expression in tumor samples appeared to be higher compared to the corresponding normal tissues. In appendix, stomach and small intestine, the expression of PD-L1 mRNA was higher in the tumor tissues compared to the respective controls. In pancreas and colon, control tissues tend to have a higher PD-L1 mRNA expression compared to tumor tissues. PD-L1 mRNA expression was higher in GEP carcinomas (p=0.0031). Conclusion: RT-PCR was found to be more sensitive in detecting PD-L1 expression than conventional IHC. This study may provide an important starting point and useful background information for future research about immunotherapy for appendix, stomach and small intestine neuroendocrine carcinomas.Item Activity of CDK4/6 inhibitors and parameters affecting survival in elderly patients in age-subgroups: Turkish Oncology Group (TOG) retrospective studyKahraman, S; Hizal, M; Demirel, BC; Guven, DC; Gumusay, O; Uluc, BO; Bayram, E; Gulbagci, B; Yasar, A; Davarci, SE; Mocan, EE; Acar, O; Isik, D; Aydin, E; Karakas, Y; Ozcelik, M; Keser, M; Okutur, SK; Eren, O; Menekse, S; Aydin, D; Yilmaz, F; Dogan, O; Ozkanli, G; Yucel, H; Sunar, V; Aykan, MB; Ozdemir, O; Duman, BB; Keskinkilic, M; Sakalar, T; Inal, A; Karaoglanoglu, M; Aksoy, A; Er, MM; Turhal, NS; Kalkan, NO; Sendur, MANHighly selective inhibitors of cyclin-dependent kinase 4 and 6 (CDK4/6is) have emerged as a standart of care for first- and second-line therapies in combination with endocrine therapy (ET) for HR+/HER2- metastatic breast cancer (MBC) patients. It has been reported that combination therapy is more effective than ET alone and is safe in elderly patients as well as young patients. Nevertheless, elderly and very old patients with HR+/HER2-MBC treated with CDK4/6 inhibitor (CDK4/6i) combinations are relatively underrepresented in randomized controlled trials. To contribute to the literature, we investigated the real-world efficacy, factors associated with survival and the rates of adverse events (AEs) of the treatment with palbociclib or ribociclib plus ET in the HR+/HER2- MBC patient cohort over the age of 65 for age subgroups. In this retrospective study, 348 patients were divided into subgroups: 65-69 years old, 70-79 years old and 80 years and older. Median PFS (mPFS) for whole group was 18.3 (95% CI,14.3-22.3) months. There was no significant difference in mPFS between age groups (p = 0.75). The estimated median OS (mOS) was 39.5 (95% CI, 24.9-54.1) months and there was no significant difference between age groups (p = 0.15). There was a meaningfull numerical difference that did not reach statistical significance in patients who received CDK4/6i treatment as the first line for MBC. Grade 3-4 AEs were reported in 42.7% for the entire group, and neutropenia was the most common (37.3%). It can be concluded that combination therapy with palbociclib or ribociclib with an ET partner has similar efficacy and is safe among subgroups of older patients diagnosed with HR+/HER2-MBC.