Semra Koçtürk
Dokuz Eylül University
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Publication
Featured researches published by Semra Koçtürk.
International Journal of Neuroscience | 2004
Ayfer Yalcin; Emrah Kilinc; Semra Koçtürk; Halil Resmi; Eser Yildirim Sözmen
Oxidative stress is a likely molecular mechanism in the neurotoxicity of kainic acid (KA), an excitotoxic substance. The aim of this report was to assess the effect of melatonin co-treatment against KA by measuring the levels of Coenzyme Q10 (CoQ 10), lipid peroxidation (LPO), and Thioredoxin (Trx) mRNA in the rat hippocampus. The male rats were divided into three groups as saline, KA treatment (15 mg/kg), and KA plus melatonin (20 mg/kg). The levels of LPO and CoQ10 were determined by high pressure liquid chromatography (HPLC) consisting of fluorescence and electro-chemical detectors, respectively. The expression of the Trx gene was quantified using reverse transcription followed by real-time polymerase chain reaction (RT-PCR). The results show that the level of LPO increased although the level of CoQ10 decreased both in homogenates and mitochondria in KA-treated rats However, melatonin co-treatment attenuated the level of LPO and partially restored the level of CoQ10. Melatonin co-treatment against KA did not affect the regulation of Trx. Finally, in the context of the decreased LPO and the increased CoQ10, the results suggest that melatonin may be protective against central nervous system pathologies involving excitotoxicity or where oxidative damage may contribute to mitochondrial dysfunction.
Gynecologic Oncology | 2016
Pınar Kemik; Bahadır Saatli; Nuri Yildirim; Vahit Doğu Kemik; Banu Deveci; Mustafa Cosan Terek; Semra Koçtürk; Meral Koyuncuoglu; Ugur Saygili
OBJECTIVE The objective of this study is to determine the efficiency of YKL-40, HE-4 and DKK-3 levels in early diagnosis of patients with endometrial cancer and in the pre-operative estimation of the prognostic parameters such as stage, grade and the extension of the disease. METHODS In this prospective study, 50 patients diagnosed with endometrial cancer and 50 women as a control group, who applied to Dokuz Eylul University and Ege University Faculties of Medicine, Obstetrics and Gynecology Clinics between May 2011-May 2012 were included. CA125, HE-4, YKL-40 and DKK-3 serum levels were measured by ELISA and compared between two groups. The relation between serum levels and histopathological results, extension of disease and prognostic factors were analyzed. RESULTS Preoperative serum CA125, HE-4 and YKL-40 levels were significantly higher in endometrial cancer group (p<0.001). Serum HE-4 levels were significantly higher in advanced stages (p=0.004). When we examined early stage patients, YKL-40 levels were significantly higher in non-endometrioid histology compared with endometrioid adenocarcinoma (p=0.022). We also examined the relation between the markers and prognostic factors. Different from other markers, HE-4 levels were significantly higher in endometrial cancer patients who had lymphovascular space involvement, lower uterine segment involvement, endocervical stromal involvement, and deep myometrial invasion. CONCLUSION YKL-40 and HE-4 were significantly higher in patients with endometrial cancer. HE-4 seems to be superior to YKL-40 in discriminating early and advanced stages. Additionally, HE4 is significantly correlated with prognostic factors. HE-4 and YKL-40 may be successful in early determination of endometrial cancer and in detection of high risk subsets before surgery.
Journal of Thyroid Research | 2016
Ergul Mutlu Altundag; Tolga Kasacı; Ayşe Mine Yılmaz; Betul Karademir; Semra Koçtürk; Yavuz Taga; A. Süha Yalçin
In this study, we have investigated the antiproliferative effect of quercetin on human papillary thyroid cancer cells and determined the apoptotic mechanisms underlying its actions. We have used different concentrations of quercetin to induce apoptosis and measured cell viability. Apoptosis and cell cycle analysis was determined by flow cytometry using Annexin V and propidium iodide. Finally, we have measured changes in caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP) protein expression levels as hallmarks of apoptosis and Hsp90 protein expression level as a marker of proteasome activity in treated and control cells. Quercetin treatment of human papillary thyroid cancer cells resulted in decreased cell proliferation and increased rate of apoptosis by caspase activation. Furthermore, it was demonstrated that quercetin induces cancer cell apoptosis by downregulating the levels of Hsp90. In conclusion, we have shown that quercetin induces downregulation of Hsp90 expression that may be involved in the decrease of chymotrypsin-like proteasome activity which, in order, induces inhibition of growth and causes cell death in thyroid cancer cells. Thus, quercetin appears to be a promising candidate drug for Hsp90 downregulation and apoptosis of thyroid cancer cells.
Human & Experimental Toxicology | 2015
Seren Gulsen Gurgen; At Yücel; Aç Karakuş; D Çeçen; G Özen; Semra Koçtürk
The purpose of this study was to investigate the long- and short-term inflammatory and apoptotic effects of whey protein on the livers of non-exercising rats. Thirty rats were divided into three groups namely (1) control group, (2) short-term whey (WS) protein diet (252 g/kg for 5 days), and (3) long-term whey (WL) protein diet (252 g/kg for 4 weeks). Interleukin 1β (IL-1β), IL-6, tumor necrosis factor α (TNF-α), and cytokeratin 18 (CK-18-M30) were assessed using enzyme-linked immunosorbent assay and immunohistochemical methods. Apoptosis was evaluated using the terminal transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) method. Hepatotoxicity was evaluated by quanitation of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). Based on the biochemical levels and immunohistochemical results, the highest level of IL-1β was identified in the WL group (p < 0.01). The IL-6 and TNF-α results were slightly lower in the WS group than in the control group and were highest in the WL group (p < 0.01). The CK-18-M30 and TUNEL results were highest in the WS group and exhibited medium intensity in the WL group (p < 0.01). AST results were statistically significant for all groups, while our ALT groups were particularly significant between the WL and control groups (p < 0.01). The results showed that when whey protein is used in an uninformed manner and without exercising, adverse effects on the liver may occur by increasing the apoptotic signal in the short term and increasing inflammatory markers and hepatotoxicity in the long term.
Free Radical Biology and Medicine | 2014
Ceyda Crek; Ergul Mutlu Altundag; Betul Karademir; Semra Koçtürk; Nesrin Kartal Ozer; Yavuz Taga
Colon carcinoma is the third among the cancer related deaths. The role of pro-apoptotic Bax protein on the resveratrol related apoptosis, mitochondrial membrane potential and signal pathways has not been identified in colon carcinoma cells. In this direction, HCT-116 bax positive and HCT-116 negative cell lines were utilized to detect the apoptotic effect and I?B, MEK1 and STAT 3 signal transduction pathways of resveratrol. The impact on the cell viability and IC50 value of resveratrol has been determined via WST-1 viability assay. The ratio of apoptosis has been evaluated via flow cytometry following Annexin V/Propidium iodide (PI) double staining. Changes in the mitochondrial membrane potential have been analyzed by flow cytometry and JC-1 fluorometric staining. IkB, MEK1 and STAT3 molecules were measured by Enspire device. Data showed the IC50 value for resveratrol as 50M. According to the flow cytometry, apoptosis ratio has been determined as 29.65% in the experimental group of bax positive cells, as 13.98% in the experimental group of bax negative cells. Changes in the membrane potential has been established as 8.62% in the experimental group of bax positive cells, as 97.98% in the experimental group of bax negative cells. When the obtained data from Enspire device was reviewed; bax positive cells I?B phosphorylations were found as as 5.22 for experimental groups; MEK1 phosphorylations were found as and as 1.15 for experimental groups; STAT 3 phosphorylations were found as and as 2.52 for experimental groups. In HCT-116 bax negative cells, I?B phosphorylation were and 2.71 in experimental groups; MEK1 phosphorylation were 1.18 in experimental groups; STAT 3 phosphorylation were 1.54 in experimental groups. Our data show that Bax protein plays role in the apoptotic effect of resveratrol by altering mitochondrial membrane potential and mitochondrial membrane permeability, signal transduction and the absence of Bax increase the sensitivity of HCT-116 colon carcinoma cells to apoptosis.
Nutrition and Cancer | 2018
Ergul Mutlu Altundag; Ayşe Mine Yılmaz; Semra Koçtürk; Yavuz Taga; A. Süha Yalçin
ABSTRACT Chronic myeloid leukemia is a major hematopoietic malignancy characterized by expansion of myeloid cells. In this study, we have investigated whether quercetin, curcumin and their combination induce apoptosis and inhibit growth of K562 cells. We have observed that quercetin and curcumin combination induced apoptosis accompanied by increased ROS and decreased GSH levels as well as loss of mitochondrial membrane potential. Our mRNA and protein expression results suggested that cytochrome c was released from mitochondria causing PARP and caspase-9 cleavages, the hallmarks of mitochondrial apoptotic pathway. We believe that triggering of apoptosis is mostly via mitochondrial pathway and ROS generation may induce impairment of mitochondrial membrane potential. The use of quercetin and curcumin combination potentiates individual apoptotic effects of the polyphenols and reduces their effective dose thereby preventing potential toxic effects on normal cells. Additional preclinical studies and clinical trials are certainly required to further validate their usefulness as potent anticancer agents.
national biomedical engineering meeting | 2016
Aylin Kara; Semra Koçtürk; Berivan Cecen; Guven Erbil; Uygar Sacik; Hasan Havitcioglu
The main function of the meniscus is load distribution and therefore stresses reduction in the knee joint, thereby frequently occurring cartilage damage. The meniscus leads to variety experimental and clinical research due to important function of the human body.
Turkish Journal of Biochemistry-turk Biyokimya Dergisi | 2015
Ayşe Mine Yılmaz; Ergul Mutlu Altundag; Gülşah Gedik; Semra Koçtürk; A. Süha Yalçin; Yavuz Taga
Abstract Objective: Dendritic cells (DCs) are members of the mammalian immune system and are considered to be the most powerful antigen presenting cells. They are responsible for the induction of T-cells or T-cell dependent immunity and tolerance. In this study we have investigated the effect of different serum supplements on generation and yield of mature dendritic cells isolated from peripheral blood mononuclear cells. Methods: Three different serum supplements (10% Fetal Bovine Serum, 1% Human Serum Albumin and 1% autologous serum) were compared with serum-free media to identify the role and importance of serum supplements on DC cultivation. Effect of different media on maturation signs (CD40, CD80, CD86, CD209a) and cytokine release (TNF-α, IL-10, IL-12, IL-6) was examined. Results: DCs generated in serum-free media was similar to those of cells in medium with autologous serum. Few dendritic-like cells were observed in fetal bovine serum and human serum albumin. The effect of different media on maturation of DCs was compared phenotypically and increased expression of CD80, CD86 and CD209a identified maturation and yield of DCs. Conclusion: Our results suggest that serum free media can be used to overcome potential drawbacks associated with different serum containing supplements. Özet Amac: Dendritik hucreler (DC), memeli immun sistemindeki en guclu antijen sunan hucreler olarak kabul edilir. Bu hucreler, T-hucrelerin uyarılması ile T-hucre bağımlı bağışıklıktan sorumludur. Bu calışmada farklı serumların periferik kandan izole edilen mononukler hucrelerin olgun dentritik hucrelere farklılaşması uzerine etkileri araştırılmıştır. Metod: DC kulturlerindeki serum desteklerinin rolunu tanımlamak uzere, Fetal Sığır Serumu, İnsan Serum Albumini ve Otolog serum iceren besiyerlerinin etkisi serumsuz ortam ile karşılaştırılmıştır. Olgunlaşma işaretleri (CD40, CD80, CD86, CD209a) ve sitokin salınımları (TNF-α, IL-10, IL-12, IL-6) acısından incelenmiştir. Bulgular: Serumsuz ortamda farklılaştırılan hucreler ile otolog serum iceren hucrelerin benzer ozellikte olduğu buna karşılık fetal sığır serumu ile insan serum albumini iceren besiyerlerinin az sayıda dendritik hucre oluşturdukları gozlenmiştir. Farklı ortamların dendritik hucrelerdeki yuzey belirteclerinin etkisine bakıldığında CD80, CD86 ve CD209a artışı tanımlandı. Sonuc: DC uretiminde farklı faktorlerin hesaba katılması gerektiği ve serumsuz ortamların daha başarılı sonuclar verdiği duşunulmektedir.
European Journal of Applied Physiology | 2008
Semra Koçtürk; Berkant Muammer Kayatekin; Halil Resmi; Osman Açikgöz; C. Kaynak; E. Özer
Neurochemical Research | 2016
Özlem Gürsoy Çalan; Pinar Akan; Aysenur Cataler; Cumhur Dogan; Semra Koçtürk