Browsing by Author "Yildirim, M"
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Item Synthesis of Novel crosslinked Poly(azomethine-urethane)s: Photophysical and thermal propertiesAvci, A; Kamaci, M; Kaya, I; Yildirim, MThis paper describes synthesis, photophysical, electrochemical and thermal properties of some new flexible crosslinked poly(azomethine-urethane)s. Synthesis procedure includes two main steps: The first one is the synthesis of a polyurethane prepolymer (TP) using toluene-2,4-diisocyanate and 2,4-dihydroxy benzaldehyde, and the second step is the synthesis of resulting flexible crosslinked poly(azomethineurethane) derivatives by conventional polycondensation reaction of TP with different aliphatic diamines. Diamines with various chain lengths (6-12 methylene numbers) were used to obtain various resulting polymers with different physical properties. Photophysical properties of the flexible crosslinked poly(azomethine-urethane)s were investigated using photoluminescence (PL). PL results showed that the flexible crosslinked poly(azomethine-urethane)s exhibited multicolor emission behavior. A linear relationship was observed between the excitation energies and the obtained emission maxima. This characteristic enabled adjusting the PL color at the desired scale. Thermal and morphological properties of the polymers were also investigated using TG-DTA, DSC and AFM techniques. (C) 2015 Elsevier B.V. All rights reserved.Item New Poly(azomethine-urethane)s Including Melamine Derivatives in the Main Chain: Synthesis and Thermal CharacterizationKaya, I; Yildirim, M; Kamaci, M; Avci, AUp to date, only a few kinds of poly (azomethine-urethane)s (PAMUs) derived from aromatic hydroxy compounds were obtained and studied with thermal degradation steps. Novel PAMUs were prepared using the hydroxy-functionalized Schiff bases derived from melamine and toluene-2,4-diisocyanate. Schiff base prepolymers were synthesized by the condensation reaction of melamine with 4-hydroxybenzaldehyde and 2hydroxy-1-naphtaldehyde. Characterization was made by UV-Vis, FTIR, NMR, and SEC techniques. Thermal characterizations of the novel PAMUs were carried out by TG-DTA and DSC techniques. Thermal decomposition steps at various temperatures were also clarified and the physical changes of the synthesized PAMUs with exposing to the thermal degradation steps were displayed. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 120: 3027-3035, 2011Item Synthesis and thermal characterization of novel poly(azomethine-urethane)s derived from azomethine containing phenol and polyphenol speciesKaya, I; Yildirim, M; Avci, A; Kamaci, MOligophenol-based poly(azomethine-urethane)s (PAMUs) were newly synthesized in two steps. At the first step, the prepolymers including the phenol and oligophenol based-Schiff bases were prepared by a condensation reaction of o-dianisidine with 4-hydroxybenzaldehyde/3-ethoxy-4-hydroxybenzaldehyde, and the polycondensation reactions of the corresponding Schiff bases in an aqueous alkaline media. At the second step, the PAMUs were obtained by copolymerization of the prepolymers with toluene-2,4-diisocyanate (TDI) under an argon atmosphere. The structures of the obtained compounds were confirmed by FTIR, UV-vis, H-1 NMR, and C-13 NMR, and size exclusion chromatography (SEC) techniques. The synthesized compounds were also characterized by TG-DTA and DSC analyses. Thermal decomposition steps at various temperatures were clarified by FTIR analyses of the degraded products. The physical changes to the synthesized PAMUs after exposing them to the thermal degradation steps are displayed.Item Filtration and removal performances of membrane adsorbersYurekli, Y; Yildirim, M; Aydin, L; Savran, MMembrane adsorbers are promising candidates for the efficient and effective removal of heavy metals in waste water due to their unattainable adsorption and filtration capabilities. In the present study, zeolite nanoparticles incorporated polysulfone (PSf10) membrane was synthesized by means of non solvent induced phase separation technique for the removal of lead and nickel ions in water. PSf10 showed a remarkable sorption capability and after repeated (adsorptionidesorption)(5) cycles in batch experiments, it preserved 77% and 92% of its initial sorption capacity for the lead and nickel, respectively. Addition of nanoparticles increased the pore radius of the native PSf from 10 to 19 nm, while bovine serum albumin rejection remained unchanged at 98%. Increments in the pore size and enhancement in hydrophilicity caused to increase hydraulic permeability of the native PSf from 23 to 57 L/m(2) h bar. Cross-flow filtration studies revealed that the filtrate concentrations were inversely affected by the initial metal concentration and transmembrane pressure due to reaction limited region. Nonlinear rational regression model perfectly described the filtration behavior of the PSf10 within the experimental range and suggested that lower initial metal concentration and pressure with a short filtration time should be selected for the target response to be minimum. (C) 2017 Elsevier B.V. All rights reserved.Item Sol-gel synthesis of 13-93 bioactive glass powders containing therapeutic agentsDeliormanli, AM; Yildirim, MIn the current study cerium or gallium-containing silicate based 13-93 bioactive glass powders were prepared using sol-gel method. Cerium and gallium ions were chosen due to their well-known therapeutic actions and antimicrobial properties. Effect of cerium and gallium substitution (up to 5w%) on the in vitro bioactivity, and mechanical properties of the prepared powders and scaffolds were assessed. Results revealed that, additions of cerium or gallium has no significant negative effect for in vitro bioactivity and hydroxyapatite forming ability of the glass for long immersion times in simulated body fluid. An increase in mechanical properties was observed in cerium doped (>3%) glass samples presumably due to CeO2 formation during sintering. It was concluded that bioactive glass powders containing therapeutic metal ions prepared in the study via sol-gel process may find applications in biomedical applications in near future.Item Leishmania kinetoplast DNA contributes to parasite burden in infected macrophages: Critical role of the cGAS-STING-TBK1 signaling pathway in macrophage parasitemiaYilmaz, IC; Dunuroglu, E; Ayanoglu, IC; Ipekoglu, EM; Yildirim, M; Girginkardesler, N; Ozbel, Y; Toz, S; Ozbilgin, A; Aykut, G; Gursel, I; Gursel, MLeishmania parasites harbor a unique network of circular DNA known as kinetoplast DNA (kDNA). The role of kDNA in leishmania infections is poorly understood. Herein, we show that kDNA delivery to the cytosol of Leishmania major infected THP-1 macrophages provoked increased parasite loads when compared to untreated cells, hinting at the involvement of cytosolic DNA sensors in facilitating parasite evasion from the immune system. Parasite proliferation was significantly hindered in cGAS- STING- and TBK-1 knockout THP-1 macrophages when compared to wild type cells. Nanostring nCounter gene expression analysis on L. major infected wild type versus knockout cells revealed that some of the most upregulated genes including, Granulysin (GNLY), Chitotriosidase-1 (CHIT1), Sialomucin core protein 24 (CD164), SLAM Family Member 7 (SLAMF7), insulin-like growth factor receptor 2 (IGF2R) and apolipoprotein E (APOE) were identical in infected cGAS and TBK1 knockout cells, implying their involvement in parasite control. Amlexanox treatment (a TBK1 inhibitor) of L. major infected wild type cells inhibited both the percentage and the parasite load of infected THP-1 cells and delayed footpad swelling in parasite infected mice. Collectively, these results suggest that leishmania parasites might hijack the cGAS-STING-TBK1 signaling pathway to their own advantage and the TBK1 inhibitor amlexanox could be of interest as a candidate drug in treatment of cutaneous leishmaniasis.Item A multicenter study of radiologically isolated syndrome in children and adolescents: Can we predict the course?Yilmaza, D; Teber, S; Gueltutan, P; Yildirim, M; Bektas, Ö; Alikiliç, D; Güngör, M; Kara, B; Öncel, I; Dilek, TD; Saltik, S; Kanmaz, S; Yilmaz, S; Tekgül, H; Çavusoglu, D; Karaoglu, P; Yilmaz, Ü; Orak, SA; Güngor, O; Anlar, BObjectives: To evaluate clinical characteristics, imaging features and etiological profile of Radiologically Isolated Syndrome (RIS) along with clinical and radiological follow-up.Methods: Demographic, clinical and radiological data of patients younger than 18 years fulfilling the criteria for RIS were retrospectively analyzed. RIS was defined by the detection of lesions meeting the revised 2010 McDonald Criteria for dissemination in space on magnetic resonance imaging (MRI) in the absence of any symptoms of demyelinating disease or an alternative cause for the MRI findings.Results: There were total 69 patients (38 girls, 31 boys). The median age at index MRI was 15.7 years, and median follow-up time was 28 months. The most common reason for neuroimaging was headache (60.9%). A first clinical event occurred with median 11 months in 14/69 (20%) of cases. Those with oligoclonal bands (OCB) in cerebrospinal fluid (CSF) and follow-up longer than 3 years were more likely to experience a clinical event (p<0.05): 25% of those with OCB manifested clinical symptoms within the first year and 33.3% within the first two years compared to 6.3% and 9.4%, respectively in those without OCB. Radiological evolution was not associated with any variables: age, sex, reason for neuroimaging, serum 25-hydroxyvitamin D level, elevated IgG index, OCB positivity, total number and localization of lesions, presence of gadolinium enhancement, achievement of 2005 criteria for DIS and duration of follow-up.Conclusion: Children and adolescents with RIS and CSF OCB should be followed-up for at least 3 years in order to detect any clinical symptoms suggestive of a demyelinating event. Because disease-modifying treatments are not approved in RIS and no consensus report justifies their use especially in pediatric RIS, close follow-up of OCB-positive patients is needed for early recognition of any clinical event and timely initiation of specific treatment.Item The effect of personal, familial, and environmental characteristics on acne vulgaris: a prospective, multicenter, case controlled studyKaradag, AS; Balta, I; Saricaoglu, H; Kiliç, S; Kelekçi, KH; Yildirim, M; Arica, DA; Öztürk, S; Karaman, G; Çerman, AA; Bilgili, SG; Turan, E; Demirci, MM; Uzunçakmak, TK; Güvenç, SC; Ataseven, A; Ferahbas, A; Aksoy, B; Çölgeçen, E; Ekiz, Ö; Demir, FT; Bilgiç, Ö; Çakmak, S; Uçmak, D; Özuguz, P; Konkuralp, YK; Ermertcan, AT; Gökdemir, G; Baskan, EB; Alyamaç, G; Sanli, HBACKGROUND: There are only a few studies about epidemiological features of acne vulgaris in the literature. The aim of this study was to analyze demographic, clinical, familial and environmental characteristics of acne, the role of diet and aggravating factors and association of these factors with acne severity. METHODS: Patients with a diagnosis of mild-moderate to severe acne were consecutively interviewed at the participating centers during the study period. RESULTS: A total of 3826 patients and 759 control patients were involved in this study. Mild acne was the most common type of acne, and most of the lesions were localized on face followed by the trunk. The severity of acne was worse in patients who had a positive family history of acne. The most common triggering factor was psychological stress. We found a positive correlation with chocolate, bread, green tea, milk, white sugar, ripe banana, ice cream, apple, orange, and red meat consumption. As we compare the acne severity according to geographical features we detected mild-moderate acne was more common in Mediterranean region and severe acne was more common in East Anatolian region. Family history positivity was more common in Aegean region and least common in Central Anatolian region. There was statistically significant relationship as we compare acne severity and dietary factors such as chocolate, dairy products such as milk, sunflower seed consumption within the geographical regions. CONCLUSIONS: This study presents the demographic and clinical characteristics of acne patients in Asian and the European parts of Turkey. We believe that this study will provide a useful overview of acne in Turkey.Item Prognostic factors in patients with metastatic urothelial carcinoma who have treated with AtezolizumabTural, D; Ölmez, ÖF; Sümbül, AT; Özhan, N; Çakar, B; Köstek, O; Ekenel, M; Erman, M; Coskun, HS; Selçukbiricik, F; Keskin, Ö; Türköz, FP; Oruç, K; Bayram, S; Bilgetekin, I; Yildiz, B; Sendur, MAN; Paksoy, N; Dirican, A; Erdem, D; Selam, M; Tanriverdi, Ö; Paydas, S; Urakçi, Z; Atag, E; Güncan, S; Ürün, Y; Alkan, A; Kaya, AO; Özyükseler, DT; Taskaynatan, H; Yildirim, M; Sönmez, M; Basoglu, T; Gündüz, S; Kiliçkap, S; Artaç, MBackground Atezolizumab (ATZ) has demonstrated antitumor activity and manageable safety in previous studies of patients with metastatic platinum-resistant urothelial carcinoma. However, the response rate of Atezolizumab was modest. In the current study, we evaluated the pretreatment prognostic factors for overall survival in patients with metastatic urothelial carcinoma who have progressed after first-line chemotherapy in the Expanded-Access Program of Atezolizumab. Patients and methods In this study, we present a retrospective analysis of 113 patients with urothelial cancer treated with ATZ after progression on first-line chemotherapy. Data of the patients was obtained from patient files and hospital records. Eligible patients included metastatic urothelial carcinoma patients treated with at least one course of ATZ. Univariate analysis was used to identify clinical and laboratory factors that significantly impact OS. Variables were retained for multivariate analysis if they had a statistical relationship with OS (p < 0.1), and then included a final model of p < 0.05. Results The median follow-up duration was 23.5 months. Of the patients, 98 (86.7%) were male and 13.3% were female. The median age was 65 years of age (37-86). In univariate analysis, primary tumor location in the upper tract, increasing absolute neutrophil count (ANC), increasing absolute lymphocyte count, neutrophil-to-lymphocyte ratio (NLR) > 3, liver metastases, baseline creatinine clearance less (GFR) than 60 ml/min, Eastern Cooperative Oncology Group (ECOG) performance status (1 >=), and hemoglobin levels below 10 mg/dl were all the significantly associated with OS. Three of the five adverse prognostic factors according to the Bellmunt criteria were independent of short survival: liver metastases HR 3.105; 95% CI 1.673-5.761; p < (0.001), ECOG PS (1 >=) HR 2.184; 95% CI 1.120-4.256; p = 0.022, and Hemoglobin level below 10 mg/dl HR 2.680; 95% CI 1.558-4.608; p < (0.001). In addition, NLR > 3 hazard ratio [HR] 2.092; 95% CI 1.031-4.243; p = 0.041 and GFR less than 60 ml/min HR 1.829; 95% CI 1.1-3.041; p = 0.02, maintained a significant association with OS in multivariate analysis. Conclusions This model confirms the Bellmunt model with the addition of NLR > 3 and GFR less than 60 ml/min and can be associated with clinical trials that use immunotherapy in patients with bladder cancer.Item Optic neuritis in Turkish children and adolescents: A multicenter retrospective studyDirek, MÇ; Besen, S; Öncel, I; Günbey, C; Özdogan, O; Orgun, LT; Sahin, S; Cansu, A; Yildiz, N; Kanmaz, S; Yilmaz, S; Tekgül, H; Türkdogan, D; Ünver, O; Thomas, GO; Basibüyük, S; Yilmaz, D; Kurt, AN; Gültutan, P; Özsoy, Ö; Yis, U; Kurul, SH; Güngör, S; Özgör, B; Karadag, M; Dündar, NO; Gençpinar, P; Bildik, O; Orak, SA; Kabur, ÇÇ; Kara, B; Karaca, Ö; Canpolat, M; Gümüs, H; Per, H; Yilmaz, Ü; Karaoglu, P; Ersoy, Ö; Tosun, A; Öztürk, SB; Yüksel, D; Atasoy, E; Gücüyener, K; Yildirim, M; Bektas, Ö; Çavusoglu, D; Yarar, Ç; Güngör, O; Mert, GG; Sarigeçili, E; Edizer, S; Çetin, ID; Aydin, S; Diler, B; Özdemir, AA; Erol, I; Okuyaz, Ç; Anlar, BBackground: Various etiologies may underlie optic neuritis, including autoantibody-mediated disorders described in the last decade. We re-examined demographic, clinical, laboratory features and prognostic factors in pediatric patients with autoimmune optic neuritis according to current knowledge.Methods: Cases of pediatric ON from 27 centers in Turkiye diagnosed between 2009 and 2022 were included for retrospective evaluation.Results: The study included 279 patients, 174 females and 105 males, with a female-to-male ratio of 1.65. The average age at onset was 12.8 +/- 3.4 years, and mean follow-up, 2.1 years (range: 1-12.1 years). Patients <10 years old were grouped as prepubertal and those >= 10 years old as others. The diagnoses made at the end of follow-up were multiple sclerosis associated optic neuritis (n = 90, 32.3 %), single isolated optic neuritis (n = 86, 31 %), clinically isolated syndrome (n = 41, 14.7 %), myelin oligodendrocyte glycoprotein antibody associated optic neuritis (n = 22, 7.9 %), and relapsing isolated optic neuritis (n = 18, 6.5 %). Predominant diagnoses were myelin oligodendrocyte glycoprotein antibody associated optic neuritis and acute disseminated encephalomyelitis associated optic neuritis in the prepubertal group and multiple sclerosis associated optic neuritis in the older group. Recurrences were observed in 67 (24 %) patients, including 28 with multiple sclerosis associated optic neuritis, 18 with relapsing isolated optic neuritis, 11 with myelin oligodendrocyte glycoprotein antibody associated optic neuritis, 8 with aquaporin-4 antibody related optic neuritis, and 2 with chronic relapsing inflammatory optic neuropathy. Recurrences were more common among female patients. Findings supporting the diagnosis of multiple sclerosis included age of onset >= 10 years (OR=1.24, p = 0.027), the presence of cranial MRI lesions (OR=26.92, p<0.001), and oligoclonal bands (OR=9.7, p = 0.001). Treatment in the acute phase consisted of intravenous pulse methylprednisolone (n = 46, 16.5 %), pulse methylprednisolone with an oral taper (n = 212, 76 %), and combinations of pulse methylprednisolone, plasmapheresis, or intravenous immunoglobulin (n = 21, 7.5 %). Outcome at 12 months was satisfactory, with 247 out of 279 patients (88.5 %) demonstrating complete recovery. Thirty-two patients exhibited incomplete recovery and further combination treatments were applied. Specifically, patients with relapsing isolated optic neuritis and aquaporin-4 antibody related optic neuritis displayed a less favorable prognosis.Conclusion: Our results suggest optic neuritis is frequently bilateral in prepubertal and unilateral in peri- or postpubertal patients. Age of onset 10 or older, presence of oligoclonal bands, and brain MRI findings reliably predict the development of multiple sclerosis. The risk of developing multiple sclerosis increases mostly during the second and third years of follow-up. Relapsing isolated optic neuritis remains a separate group where the pathogenesis and outcome remain unclear. Investigation of predisposing and diagnostic biomarkers and long follow-up could help to define this group.Item Effects of treatment with clinically relevant valproate, carbamazepine, oxcarbazepine, topiramate, lamotrigine and levetiracetam on ovarian folliculogenesis in young ratsCansu, A; Gurgen, SG; Demirhan, YN; Kart, PO; Yildirim, M; Alver, A; Yenilmez, E; Sonmez, FMAim: To determine the effects of valproate (VPA), carbamazepine (CBZ), oxcarbazepine (OXC), topiramate (TPM), lamotrigine (LTG), and levetiracetam (LEV) on ovarian folliculogenesis in young rats. Methods: Forty-nine female Wistar rats, aged 21-24 days, were divided equally into 7 experimental groups. These were given tap water over 21-24 days (control group), 300 mg/kg of VPA, 150 mg/kg of CBZ, 150 mg/kg of OXC, 100 mg/kg of TPM, 10 mg/kg of LTG, or 50 mg/kg of LEV daily in 2 doses via oral gavage until the end of puberty. At the end of the study, the estrous cycle of each rat was monitored daily, and those rats in pro-estrus or di-estrus were sacrificed and the ovaries removed. Serial sections obtained from the ovaries were stained with hematoxylin and eosin, and the corpora lutea and follicles were enumerated. Apoptotic cells were detected using the TUNEL technique. Various serial sections were immunohistochemically stained with proliferating cell nuclear antigen (PCNA), growth differentiation factor (GDF)-9, caspase-3, caspase-9, transforming growth factor beta 1 (TGF-1), and epidermal growth factor (EGF), and evaluated and photographed under a light microscope. Key Findings: The number of corpora lutea was significantly increased in the VPA, CBZ, OXC, and LTG groups compared to the control group (p < 0.001). The number of TUNEL-positive ovarian follicles was 3.3 +/- 1.1 (median, 3), 6.1 +/- 0.9 (median, 6), and 5.7 +/- 0.8 (median,6) in the control, OXC and LEV groups, respectively (p < 0.001). The number of TUNEL-positive granulosa cells was higher in all the groups treated with antiepileptics, with the exception of the TPM group, compared to the control group (p < 0.001). HSCOREs for immunohistochemical staining using PCNA, GDF-9, TGF-1 and EGF were significantly higher in the control group than in the others (p < 0.001). HSCORE for staining using caspase-3 was significantly higher in the VPA, CBZ, OXC and LEV groups, while the HSCORE was significantly lower in the TPM group than in the control group. HSCORE for staining using caspase-9 was significantly higher in the VPA, CBZ and OXC groups, while it was significantly lower in the TPM group than in the control group (p < 0.001). Significance: Exposure to VPA, CBZ, OXC, TPM, LTG and LEV caused different levels of impaired folliculogenesis in young rats.