Person: YEGEN, BERRAK
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YEGEN
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BERRAK
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Publication Open Access Cerrahi menopoz oluşturulmuş sıçanların karaciğer ve böbrek dokularında oksidan/antioksidan dengenin korunmasında egzersizin ve östrojenin yararlı etkileri(2022-09-01) YÜKSEL, MERAL; ERCAN, FERİHA; YILDIRIM, ALPER; YEGEN, BERRAK; Tamer S. A. , Levent N., Yüksel M., Ercan F., Yıldırım A., Yegen B.Amaç: Bu çalışmanın amacı cerrahi olarak menopoz oluşturulan sıçanların böbrek ve karaciğerlerinde gözlenen histopatolojik ve fonksiyonel değişiklikleri ve östrojen veya egzersizin ya da östrojen-egzersiz kombinasyonunun oksidan hasar üzerine etkilerini araştırmaktır.Materyal ve Metot: Anestezi altında Sprague Dawley dişi sıçanlara (n=32) bilateral overiektomi uygulandı ve tüm sıçanlar rastgele olarak iki gruba ayrıldı. Sıçanların yarısına normal içme suyu, diğer yarısının içme sularına östrojen (1mg/kg/gün) eklendi. İki hafta sonra gruplar kendi içlerinde sedanter ve egzersiz (5 gün/hafta, 30 daki-ka, 8 hafta) gruplarına ayrıldı. Deney protokolünün sonun-da serum, karaciğer ve böbrek örnekleri biyokimyasal ve histopatolojik incelemeler için alındı. Femurda da histopa-tolojik değerlendirme yapıldı.Bulgular: Cerrahi olarak menopoz oluşturulan sıçan-larda östrojenin böbrek dokusunda nötrofil infiltrasyonunu ve reaktif oksijen türlerinin üretimini baskılayarak koruyu-cu etki gösterdiği, kemik kütlesinde hafif düzeyde artışa neden olduğu, ancak karaciğerin antioksidan glutatyon düzeyinde azalmaya yol açtığı belirlenmiştir. Buna karşın, östrojen uygulaması menopozda yapılan egzersiz nedeniy-le karaciğerde oluşan oksidan stresi engellemiştir. Egzer-sizle veya egzersize östrojen tedavisinin eklenmesiyle böbrek fonksiyonları önemli ölçüde etkilenmezken, kemik yapısında tek başına östrojene kıyasla daha olumlu deği-şiklikler gözlenmiştir.Sonuç: Östrojen replasmanı kemik dokusundaki olum-lu etkilerinin yanı sıra karaciğer ve böbrekte oksidan stresi azaltmakta ve özellikle karaciğerde egzersize bağlı gelişen oksidan stresi baskılayarak koruyucu etki göstermektedir.Publication Open Access Neuropeptide W Exhibits Preventive and Therapeutic Effects on Acetic Acid-Induced Colitis via Modulation of the Cyclooxygenase Enzyme System(2023-01-01) ARABACI TAMER, SEVİL; ERCAN, FERİHA; YEGEN, BERRAK; ARABACI TAMER S., Akbulut S., Erdogan O., Cevik O., ERCAN F., YEGEN B.Background The novel peptide neuropeptide W (NPW) was originally shown to function in the control of feeding behavior and energy homeostasis. The aim of this study was to elucidate the putative preventive and therapeutic effects of NPW on colitis-associated oxidative injury and the underlying mechanisms for its action.Methods Sprague-Dawley rats in the acute colitis groups received NPW (0.5, 1 or 5 mu g/kg/day) injections prior to induction of colitis with acetic acid, while the chronic colitis groups were treated after the induction of colitis. In both acute and chronic colitis (CC) groups, treatments were continued for 5 days and the rats were decapitated at the 24th hour of the last injections and colon tissues were collected for assessments.Results NPW pretreatment given for 5 days before colitis induction, as well as treating rats with NPW during the 5-day course of CC, abolished colonic lipid peroxidation. NPW treatment prevented colitis-induced reduction in blood flow, diminished neutrophil infiltration, and pro-inflammatory cytokine responses. NPW pretreatment only at the higher dose reduced colonic edema and microscopic score and preserved colonic glutathione stores. Elevations in cyclooxygenase (COX) enzyme activity and COX-1 protein level during the acute phase of colitis as well as reduction in COX-2 were all reversed with NPW pretreatment. In contrast, NPW treatment was effective in reducing the elevated COX-2 concentration during the chronic phase.Conclusions NPW alleviates acetic acid-induced oxidative colonic injury in rats through the upregulation of colonic blood flow as well as the inhibition of COX-2 protein expression and pro-inflammatory cytokine production.Publication Open Access Rethinking large group lectures – how far in this format(2022-05-01) SEVİM, MUSTAFA; ERZİK, CAN; YEGEN, BERRAK; GÜLPINAR, MEHMET ALİ; AKTURAN S., SEVİM M., ERZİK C., YEGEN B., GÜLPINAR M. A.Objective: The aim of this study is to determine the perceptions, attitudes, and behaviour of medical students and lecturers regarding the lectures and their effects on students’ learning behaviour. Materials and Methods: This was a qualitative study including multi-methods. Researchers observed lecture ambiance and activities in two courses. Lectures were observed and slide-presentations were evaluated. Additionally, in-depth and focus group interviews were conducted. Results: Two researchers attended and observed 75 lectures. The average number of attendees was 51.21. Eighty percent of lecturers did not introduce any activities to attract attention and prepare students for the lecture. Only 12% of lectures were taught interactively. Of the evaluated 43 (69.80%) slide-presentations, sufficient association or integration was not made between clinical and basic sciences. Conclusion: This study revealed that the lectures created negative feelings and thoughts in students and lecturers, and led to undesirable attitudes and behaviour. It is essential to focus on giving interactive lectures which aim at developing reasoning, decision-making, and evaluation competencies. The most significant factors determining students’ attendance and appraisal of the lectures were related to the preparation of the lecturers, the intensity of the content, integration between basic science and clinical science, and the presentation skills.Publication Open Access Melatonin alleviates ovariectomy-induced cardiovascular inflammation in sedentary or exercised rats by upregulating SIRT1(2022-12-01) ERCAN, FERİHA; YILDIRIM, ALPER; YEGEN, BERRAK; Arabacı Tamer S., Altınoluk T., Emran M., Korkmaz S., Yüksel R. G., Baykal Z., Dur Z. S., Levent H. N., Ural M. A., Yüksel M., et al.© 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.We aimed to evaluate the impact of hormone replacement, melatonin, or exercise alone or their combination on oxidative damage and functional status of heart, brain, and aorta of ovariectomized (OVX) rats and to determine whether the signaling pathway is dependent on sirtuin-1 (SIRT1). Ovariectomized Sprague Dawley rats were orally given either a hormone replacement therapy (1 mg/kg/day,17β estradiol; HRT) or melatonin (4 mg/kg/day) or HRT + melatonin treatments or tap water, while each group was further divided into sedentary and exercise (30 min/5 days/week) groups. After the heart rate measurements and memory tests were performed, trunk blood was collected at the end of the 10th week to determine metabolic parameters in serum samples. Tissue samples of abdominal aorta, heart, and brain were taken for biochemical measurements and histopathological evaluation. Heart rates and memory performances of the OVX rats were not changed significantly by none of the applications. Melatonin treatment or its co-administration with HRT upregulated the expressions of IL-10 and SIRT1, reduced the expressions of IL-6 and TNF-α, and reduced DNA damage in the hearts and thoracic aortae of non-exercised rats. Co-administration of melatonin and HRT to exercised OVX rats reduced inflammatory response and upregulated SIRT1 expression in the aortic and cardiac tissues. The present study suggests that melatonin treatment, either alone or in combination with exercise and/or HRT, upregulates SIRT1 expression and alleviates oxidative injury and inflammation in the hearts and aortas of OVX rats. Melatonin should be considered in alleviating cardiovascular disease risk in postmenopausal women.Publication Open Access Anti-inflammatory, antioxidant and neuroprotective effects of niacin on mild traumatic brain injury in rats(2023-01-01) KOYUNCUOĞLU, TÜRKAN; AKAKIN, DİLEK; ERZİK, CAN; YÜKSEL, MERAL; YEGEN, BERRAK; Ozaydin D., Bektasoglu P. K., Koyuncuoglu T., Ozkaya S. C., Koroglu A. K., AKAKIN D., ERZİK C., YÜKSEL M., YEGEN B., Gurer B.AIM: To study the effects of niacin, a water-soluble vitamin, on inflammation, oxidative stress and apoptotic processes observed after mild traumatic brain injury (TBI). MATERIAL and METHODS: A total of 25 Wistar albino male rats were randomly divided into control (n=9), TBI + Placebo group (n=9), TBI + niacin (500 mg/kg; n=7) groups. Mild TBI was performed under anesthesia by dropping a 300 g weight from a height of 1 meter onto the skull. Behavioral tests were applied before and 24 hours after TBI. Luminol and lucigenin levels and tissue cytokine levels were measured. Histopathological damage was scored in brain tissue. RESULTS: After mild TBI, luminol and lucigenin levels were increased (p<0.001), and their levels were decreased with niacin treatment (p<0.01-p<0.001). An increased score was obtained with trauma in the tail suspension test (p<0.01), showing depressive behavior. The number of entries to arms in Y-maze test were decreased in TBI group compared to pre-traumatic values (p<0.01), while discrimination (p<0.05) and recognition indices (p<0.05) in object recognition test were decreased with trauma, but niacin treatment did not change the outcomes in behavioral tests. Levels of the anti-inflammatory cytokine IL-10 were decreased with trauma, and increased with niacin treatment (p<0.05). The histological damage score was increased with trauma (p<0.001), and decreased with niacin treatment in the cortex (p<0.05), and hippocampal dentate gyrus region (p<0.01). CONCLUSION: Niacin treatment after mild TBI inhibited trauma-induced production of reactive oxygen derivatives and elevated the anti-inflammatory IL-10 level. Niacin treatment ameliorated the histopathologically evident damage.Publication Open Access A 10-day mild treadmill exercise performed before an epileptic seizure alleviates oxidative injury in the skeletal muscle and brain tissues of the rats(2022-01-01) KAYA, ÖZLEM TUĞÇE; YEGEN, BERRAK; YÜKSEL, MERAL; YILDIRIM, ALPER; Arabaci -Tamer S., KAYA Ö. T., YÜKSEL M., YILDIRIM A., YEGEN B.© 2022 Marmara University Press, All Rights Reserved.Objective: Epileptic seizures may cause skeletal muscle injury and memory dysfunctions. The present study was aimed to investigate the possible protective effects of exercising prior to seizure on seizure-induced oxidative injury in the skeletal muscle and brain. Materials and Methods: Sprague-Dawley male rats were assigned as non-exercise (n=16) and exercise groups (n=16). Following a 3-day exercise training, exercise protocol (30 min) was performed on a treadmill for 10 days, while control rats had no exercise. On the 11th day, the epileptic seizure was induced by a single intraperitoneal injection of pentylenetetrazol (PTZ) (45 mg/kg), while the control groups were injected with saline. Passive-avoidance test was initially performed before PTZ/saline injection and repeated 72 h later for the assessment of memory function. Brain and gastrocnemius muscles were taken for histological assessments and to determine the levels of malondialdehyde (MDA) and glutathione (GSH), myeloperoxidase (MPO) activity and luminal – and lucigenin – enhanced chemiluminescence levels. Results: Exercise training alone increased the formation of reactive oxygen species and elevated the antioxidant GSH capacity of the muscle tissue in the control rats, but these effects were not observed in the muscles of the exercised rats induced with a PTZ-seizure. On the other hand, short-term exercise alone had no effect on the basal oxidative parameters of the brain tissues. Prior exercise did not alter the average seizure scores or memory performances when compared to non-exercised groups, but suppressed the PTZ-induced elevations in MDA and chemiluminescence levels as well as MPO activity in the brain. Conclusion: A 10-day mild treadmill exercise reduced the oxidative brain damage due to a single seizure-induced excitotoxicity and exerted a preconditioning effect on the skeletal muscles exposed to tonic-clonic contractions.Publication Open Access Rethinking large group lectures – how far in this format(2022-05-01) ERZİK, CAN; GÜLPINAR, MEHMET ALİ; YEGEN, BERRAK; Akturan S., Erzik C., Yegen B., Gülpınar M. A.Objective: The aim of this study is to determine the perceptions, attitudes, and behaviour of medical students and lecturers regarding the lectures and their effects on students’ learning behaviour.Materials and Methods: This was a qualitative study including multi-methods. Researchers observed lecture ambiance and activities in two courses. Lectures were observed and slide-presentations were evaluated. Additionally, in-depth and focus group interviews were conducted.Results: Two researchers attended and observed 75 lectures. The average number of attendees was 51.21. Eighty percent of lecturers did not introduce any activities to attract attention and prepare students for the lecture. Only 12% of lectures were taught interactively. Of the evaluated 43 (69.80%) slide-presentations, sufficient association or integration was not made between clinical and basic sciences.Conclusion: This study revealed that the lectures created negative feelings and thoughts in students and lecturers, and led to undesirable attitudes and behaviour. It is essential to focus on giving interactive lectures which aim at developing reasoning, decisionmaking, and evaluation competencies. The most significant factors determining students’ attendance and appraisal of the lectures were related to the preparation of the lecturers, the intensity of the content, integration between basic science and clinical science, and the presentation skills.