Browsing by Author "Dirican, Onur"

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Describing the Expression Profiles of Glutathione S-Transferase Mu and Tumor Protein 53 in Brain Tumor Tissue
(Erciyes Univ Sch Medicine, 2024) Dirican, Onur; Kaygin, Pinar; Lti, Sezen Yilmaz Saria; Yilmaz, Can; Simsek, Gulcin; Oguztuzun, Serpil; Izci, Yusuf
Objective: This study aims to explore the expression profiles of the glutathione S-transferaseMu (GST-M) isozyme and tumor protein 53 (p53) in both healthy and tumorous brain tissues. The findings are compared with clinical features and lifestyle factors to identify potential associations or correlations. Materials and Methods: We retrospectively analyzed the medical records of 149 patients diagnosed with primary or metastatic intracranial tumors. The expression levels of GST-M and p53 proteins were assessed in healthy and tumorous brain tissues using immunohistochemical staining. We also evaluated the associated clinical features and lifestyle factors. Results: There was a significant difference in the expression levels of GST-M between tumorous and healthy brain tissues, with tumor tissues showing higher expression (p<0.0001). Conversely, robust p53 expression was absent in both normal (97.3%) and tumor (78.5%) tissues. Nevertheless, a significantly higher prevalence of samples with p53 expression was found in the tumor group (p<0.0001). No associations were found between expression levels and clinical features or lifestyle risk factors. Furthermore, GST-M and p53 expression did not impact postoperative survival rates. Conclusion: The findings indicate an elevated expression of GST-M in brain tumor tissues, suggesting a potential role for GST-M in brain tumorigenesis.
Glutathione S-Transferase Enzyme Activity and Protein Expression in Patients With Recurrent Tonsillitis and Idiopathic Tonsillar Hypertrophy
(Palacky Univ, Medical Fac, 2019) Aydin, Sedat; Demir, Mehmet Gokhan; Oguztuzun, Serpil; Kilic, Murat; Yilmaz, Can; Dirican, Onur
Objectives. The palatine tonsil is a significant part of the secondary immune system. Tonsillitis and idiopathic tonsillar hypertrophy (ITH) are the most common pathologies of this component. Although there are studies on their pathogenesis, there is insufficient study of the role of antioxidant agents. Glutathione S-transferase (GST) isozymes contribute to the antioxidation reactions in the tissue via the glutathione pathway. The purpose in this study was to reveal the levels of the GST enzyme activity and protein expression of GSTP1 and GSTA1 isozymes in patients with tonsillitis and tonsil hypertrophy, and to investigate their role in the pathogenesis of these diseases. Materials and Methods. Sixteen patients with recurrent tonsillitis and 5 patients with ITH and were included in the study. Cytosolic extracts were prepared from post-tonsillectomy tissues of both patient groups and GST enzyme activities were measured. Results. The expression of GSTP1 was found to be significantly higher than GSTA1 in tissue samples of patients with ITH and recurrent tonsillitis (P<0.001). Increased GST activity and GSTP1 isozyme expression were shown in patients with recurrent tonsillitis compared to the idiopathic tonsillar hypertrophy study group.There was a positive correlation between the expressions of GSTP1 (P=0.040; r=0.47). Conclusion. Increased GST activity and GSTP1 isozymes were demonstrated histologically in the pathogenesis of ITH and recurrent tonsillitis. We believe that the data of changes in antioxidant capacity, obtained from studies with more extensive and larger samples, would support our findings.
Obezite Duyarlılığında Cyp1a1 ve Cyp1b1 Ekspresyonlarının Rolünün Araştırılması
(2022) Yilmaz-sarialtin, Sezen; Dirican, Onur; Kaygin, Pinar; Polat, Fatih; Yılmaz, Can; Bulus, Hakan; Oguztuzun, Serpil
Metabolik işleyiş, etkileri ve neden olduğu hastalıklar açısından daha multidisipliner bir bakış açısıyla anlaşılması gereken obezite, son yıllarda prevalansı ve insidansı artan hastalıklardan biri olarak görülmektedir. Bu hastalığın metabolic yolunda önemli enzim gruplarından biri olan sitokrom p450 (CYP1A1 ve CYP1B1) izozimlerinin rolünün ortaya konulması amaçlanmıştır. 2017-2019 yılları arasında Ankara Keçiören Eğitim ve Araştırma Hastanesi Genel Cerrahi Kliniği'nde obezite tanısı konulan ve bariatric cerrahi, ksenobiyotik metabolizması uygulanan 152 hastaya immünohistokimya yöntemiyle CYP1A1 ve CYPB1 izoenzimlerinin ekspresyonu araştırılmıştır. CYP1A1 açısından elde edilen bulgular; 152 kişide CYP1A1 ve CYP1B1 immünohistokimya boyama düzeyleri incelenen dokuların %12.7'sinde CYP1A1 ekspresyonu gözlenmezken; %33.3, %32.5 ve %21.4'te zayıf bir CYP1A1 ifadesi gözlenmiştir. Dokuların %71.4'ünde CYP1B1 ekspresyonu görülmezken, dokuların %28.6'sında zayıf ekspresyon izlenmiştir. Hiçbir dokuda orta veya güçlü CYP1B1 ekspresyonu gözlenmemiştir. Kadın hastalardan alınan dokuların ortalama CYP1A1 ve CYP1B1 boyama seviyeleri erkek hastalardan daha yüksek bulunmuştur. Klinik verilerden diyabet parametresi (p<0.05) ile anlamlı olduğu gözlenmiştir. Çalışmamızda elde edilen veriler ışığında obez hastalarda anlamlı CYP1A ve CYP1B1 ekspresyonları gözlenmiş ve detoksifikasyon mekanizması nedeniyle antioksidan metabolizma ve işlevsellik mevcuttur. Obez hastalarda bu enzim düzeyindeki artışın özellikle moleküler yolakta başka çalışmalarla aydınlatılması gerektiği ve benzer çalışmalara yol göstereceği düşünülmektedir.
Unveiling the Etiological Impact of Gst-M1, Gst-T1, and P53 Genotypic Variations on Brain Carcinogenesis
(Springer, 2024) Dirican, Onur; Kaygin, Pinar; Oguztuzun, Serpil; Husseini, Abbas Ali; Sarialtin, Sezen Yilmaz; Yilmaz, Can; Izci, Yusuf
Background Functional variants of glutathione-S-transferase (GST)-M1, GST-T1, p53 might modulate brain cancer risk by altering the rate of metabolism and clearance of carcinogens from the brain tissue. In this study, the role of GST-M1, GST-T1, p53 polymorphisms on brain tumor was investigated.Methods and results Brain tumor tissues of 143 patients were obtained from the Gulhane Training and Research Hospital, Department of Neurosurgery between 2019 and 2020. In the xenobiotic mechanism, the null allele frequency in the GST-T1, GST-M1 gene regions of Phase II enzymes by qPCR method were investigated. Single nucleotide polymorphism encoding Arg/Pro conversion in the p53 gene region was analyzed in 120 cases by sequence analysis method. The data were analyzed statistically with patient's demographic and clinical data. GST-M1, GST-T1, p53 genotypes of the patient group were determined. The most frequent genotype was null genotype (0/0) for GST-M1 (chi(2) = 39.756, p < 0.001). GST-M1 genotype frequencies were 30.8%, 23.1%, 44.3% for 1/1, 1/0, 0/0, respectively. The most frequent genotype was GST-T1 1/1 following by GST-T1 1/0 (chi(2) = 0.335, p = 0.846). GST-T1 genotype frequencies were 64.3%, 30.8%, 4.9% for 1/1, 1/0, 0/0, respectively. GST-M1 null genotype might be associated with the development of brain tumors. Genotype distribution obtained in p53 exon 4 codon 72; Arg/Arg was determined as 31 (25.8%), Arg/Pro 70 (58.3%), and Pro/Pro 19 (15.8%) in the case group, while there were 18 (38.3%), 23 (48.9%), and 6 (12.8%) respectively in the control group. However, the genotype distribution of p53 exon 4 codon 72 among tumorous tissue did not significantly vary from healthy control tissues (chi(2)=2.536, p = 0.281).Conclusion The null allele frequency encountered in the GST-M1, GST-T1 gene regions is consistent with the rates in the gene pool called Caucasian in the literature. GST-M1 gene polymorphism may play a crucial role in brain carcinogenesis in Turkish patients. This study based on clinical data is thought to help to understand the important epidemiological features of brain tumors.