Recep Tayyip Erdoğan Üniversitesi Kurumsal Akademik Arşivi
DSpace@RTEÜ, Recep Tayyip Erdoğan Üniversitesi tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve yayınların etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Modeling the effect of cold stratification on seed germination performance of rudbeckia fulgida aiton using response surface methodology (RSM)
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Oğuztürk, Türker; Alparslan, Cem; Sipahi, Merve; Oğuztürk, Gülcay Ercan; Topaloğlu, Ece Nur; Bayraktar, Şenol; Yüksek, Turan
This study investigates the influence of varying cold stratification durations (0–165 days) on the germination performance and early seedling development of Rudbeckia fulgida. Seeds were divided into 11 groups at 15-day intervals, using a total of 1320 seeds. For each stratification duration, an equivalent number of seeds stored at room temperature served as non-stratified controls. Results demonstrated a clear and significant increase in germination percentage with longer stratification periods (Kruskal–Wallis, H = 57.03, p < 0.001), with the highest germination observed at 135 and 165 days (96.7%). In contrast, seeds kept at room temperature exhibited low and inconsistent germination. Strong positive correlations were detected between stratification duration and both germination percentage (r = 0.914) and post-stratification seed weight (r = 0.419). Furthermore, a Response Surface Methodology (RSM) model was developed to predict germination behavior, achieving an exceptionally high 99% predictive accuracy. The RSM analysis confirmed that cold stratification duration is the dominant factor shaping germination responses in Rudbeckia fulgida Aiton. Overall, the study demonstrates that cold stratification is essential for breaking seed dormancy in R. fulgida, substantially improving propagation efficiency and offering valuable insights for nursery production, landscape practices, and restoration ecology.
Therapeutic effect of arginine, glutamine and β-hydroxy β-methyl butyrate mixture as nutritional support on dss-induced ulcerative colitis in rats
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Yılmaz Akyüz, Elvan; Akyüz, Cebrail; Yenilmez Tunoglu, Ezgi Nurdan; Dogan, Meryem; Bayram, Banu; Tutar, Yusuf
Background: Ulcerative colitis (UC) is characterized by chronic mucosal inflammation, oxidative stress, and disruption of intestinal metabolic homeostasis. Immunomodulatory nutrients such as arginine, glutamine, and β-hydroxy β-methylbutyrate (HMB) have shown potential benefits; however, their combined molecular effects on UC remain insufficiently defined. Objective: To investigate the individual and combined effects of arginine, glutamine, and HMB on inflammatory and metabolic gene expression, oxidative stress markers, and histopathological outcomes in a dextran sulfate sodium (DSS)-induced colitis model. Methods: Female Sprague Dawley rats were assigned to six groups: control, DSS, DSS + arginine, DSS + glutamine, DSS + HMB, and DSS + mixture. Colitis was induced using 3% DSS. Colon tissues were examined histologically, serum MDA, MPO, and GSH levels were quantified, and mRNA expression of IL6, IL10, COX2, NOS2, ARG2, CCR1, and ALDH4A1 was measured by RT-qPCR. Pathway enrichment analyses were performed to interpret cytokine and metabolic network regulation. Results: DSS induced severe mucosal injury, elevated MDA and MPO, reduced GSH, and significantly increased IL6, COX2, NOS2, ARG2, and CCR1 expression. Glutamine demonstrated the strongest anti-inflammatory and antioxidant effects by decreasing IL6 and COX2 and restoring GSH. Arginine primarily modulated nitric oxide–related pathways, whereas HMB increased ALDH4A1 expression and metabolic adaptation. The combination treatment produced more balanced modulation across inflammatory, chemokine, and metabolic pathways, consistent with enrichment results highlighting cytokine signaling and amino acid metabolism. Histopathological improvement was greatest in the mixture group. Conclusions: Arginine, glutamine, and HMB ameliorate DSS-induced colitis through coordinated regulation of cytokine networks, oxidative stress responses, and metabolic pathways. Their combined use yields broader and more harmonized therapeutic effects than individual administration, supporting their potential as targeted immunonutritional strategies for UC. Rather than targeting a single inflammatory mediator, this study was designed to test whether combined immunonutrient supplementation could promote coordinated regulation of cytokine signaling, oxidative stress responses, and metabolic adaptation, thereby facilitating mucosal repair in experimental colitis.
Left ventricular and left atrial strain characteristics in patients with familial mediterranean fever receiving long-term colchicine therapy
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Durak, Hüseyin; Çetin, Mustafa; Emlek, Nadir; Özyıldız, Ali Gökhan; Duman, Hakan; Ergül, Elif; Özsipahi, Ahmet; Dindar, Barış; Cüre, Osman
Background: Familial Mediterranean fever (FMF) is a chronic autoinflammatory disorder characterized by sustained systemic inflammation that may affect cardiac structure and function. Colchicine is the cornerstone of FMF therapy and has cardiovascular benefits in inflammatory settings. Methods: This cross-sectional study enrolled 106 participants: 53 patients with FMF receiving long-term colchicine therapy and 53 age- and sex-matched controls. Participants underwent transthoracic echocardiography with speckle-tracking imaging. Conventional parameters and strain-derived indices of the left ventricular (LV) and left atrial (LA) function were assessed. Correlation analyses and multivariable linear regression models were used to evaluate the association between FMF presence and cardiac strain parameters. Results: The LV ejection fractions were comparable between the groups. The FMF group showed thinner ventricular walls and larger chamber dimensions than the control group. Patients with FMF exhibited higher LA reservoir strain, while conduit and contractile atrial contributions were reduced, as shown by lower passive and active emptying fractions and reduced LA ejection fraction. LA volumes and stiffness indices were lower in the FMF group, indicating smaller and more compliant atrial structures. Left ventricular global longitudinal strain (LVGLS) was more negative in patients with FMF, indicating preserved LV longitudinal systolic function. FMF was independently associated with LVGLS and LA strain parameters after adjusting for cardiovascular risk factors. Conclusions: In patients with FMF receiving long-term colchicine therapy, cardiac strain imaging showed preserved LV longitudinal function and distinct LA mechanics with preserved reservoir strain but reduced conduit and contractile function. Strain echocardiography may provide insights into cardiac involvement in well-controlled FMF, although prospective studies are needed to clarify the clinical significance of these findings.
Turkish hazelnut extracts exert anti-proliferative and anti-cancer effects on colorectal cancer HCT-116 cells
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Bayram, Banu; Demircan, Evren; Karimidastjerd, Atefeh; Akyüz, Elvan Yılmaz; Tutar, Yusuf
The rising incidence of cancer has demanded the development of new anti-cancer chemical sources. The presence of phenolics in hazelnut cell cultures has led to the development of new and potential pharmacotherapeutic uses. Hazelnut extract has emerged as a promising candidate due to its high phytochemical content. HCT-116 colorectal cancer IC50 cell viability of Palaz and Tombul hazelnut extracts was determined as 400 μg/mL and 200 μg/mL, respectively. Flow cytometry annexin V-fluorescein isothiocyante (FITC) apoptosis detection indicated apoptosis of Tombul hazelnut extract and Palaz hazelnut extract as 23.53% and 17.47%, respectively. The apoptosis result of flow cytometry was also supported at the protein level. Hazelnut extracts resulted in an increased loss of MMP as well. The loss of MMP has significantly increased from an average of 0.61% to 16.17% in Tombul hazelnut extract and to 20.38% in Palaz hazelnut extract. This is further supported by screening MICU1, MICU2, PPAR-γ, PPARGC1A, UCP1, UCP2, and UCP3 gene expressions. Targeting apoptosis pathways, particularly MMP, is an effective strategy for cancer prevention and treatment. Hazelnut extract contains phenolic compounds, which activate these pathways, resulting in enhanced apoptosis in colorectal cancer cells. The phenolic contents of Palaz and Tombul hazelnut extracts were determined as 271.72 ± 5.3 mg gallic acid equivalent (GAE)/100 g sample dry weight (DW) and 85.23 ± 2.2 mg GAE/100 g sample DW, respectively. Further, hazelnut extract may reduce oxidative stress, contributing to its anti-cancer properties. The extracts could be utilized as functional ingredients in foods and nutraceuticals to assist with cancer prevention and treatment.
A novel ECG score for predicting left ventricular systolic dysfunction in stable angina: a pilot study
(Multidisciplinary Digital Publishing Institute (MDPI), 2026) Emlek, Nadir; Durak, Hüseyin; Çetin, Mustafa; Özyıldız, Ali Gökhan; Ergül, Elif; Yılmaz, Ahmet Seyda; Duman, Hakan
Background: Left ventricular systolic dysfunction (LVSD) is a major determinant of prognosis in patients with ischemic heart disease. Electrocardiography (ECG) is widely available, inexpensive, and may aid in identifying patients at risk. We hypothesized that a composite score derived from multiple established ECG markers could improve the detection of LVSD in patients with stable angina. Methods: In this single-center, cross-sectional study, 177 patients undergoing elective coronary angiography for stable angina were included. Patients were classified as LVSD-negative (n = 123) or LVSD-positive (n = 54) based on echocardiographic ejection fraction. ECG parameters, including fragmented QRS, pathologic Q waves, R-wave peak time, QRS duration, and frontal QRS–T angle, were assessed. Independent predictors of LVSD were identified using multivariate logistic regression. A composite ECG score was constructed by assigning one point to each abnormal parameter. Model robustness was evaluated using bootstrap resampling (1000 iterations) and 10-fold cross-validation. Results: Multivariable analysis identified prior stent implantation, fragmented QRS, pathological Q waves, R-wave peak time, frontal QRS–T angle (log-transformed), and QRS duration as independent predictors of LVSD. ROC analysis demonstrated good discriminatory performance for R-wave peak time (AUC 0.804), QRS duration (AUC 0.649), and frontal QRS–T angle (AUC 0.825) measurements. The composite ECG score showed a stepwise association with LVSD: a score of ≥2 yielded high sensitivity (88%) and negative predictive value (97%), whereas a score of ≥3 provided high specificity (100%) and positive predictive value (100%). Bootstrap resampling and cross-validation confirmed model stability and strong discriminatory performance (mean AUC, 0.964; accuracy, 0.91). Conclusions: A simple composite ECG score integrating multiple established ECG markers is associated with the robust detection of LVSD in patients with stable angina. Although not a substitute for echocardiography, this score may support early risk stratification and help identify patients who warrant further imaging evaluations. External validation in larger and more diverse populations is required before routine clinical implementation of this model.
