Onur Baykara
Istanbul University
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Featured researches published by Onur Baykara.
Acta Neurochirurgica | 2005
Mustafa Uzan; Taner Tanriverdi; Onur Baykara; Ali Metin Kafadar; Galip Zihni Sanus; E. Tureci; Cigdem Ozkara; O. Uysal; N. Buyra
SummaryBackground. Recent studies focusing on the genetic influences on outcome after head injury (HI) have suggested that different alleles of certain genes are associated with different outcomes. Interleukin-1 beta (IL-1β) gene, especially β2 polymorphism, is frequently observed in Alzheimer’s disease, a remarkable degenerative state in which HI is among the known risk factors. Therefore, the aim of this paper was to search for the possible association between the outcome and IL-1β gene polymorphism in human HI.Methods. The study group was composed of the 69 patients admitted to the neurosurgery department after HI. The severity of the initial injury was evaluated by means of the Glasgow Coma Scale and outcome six months later was assessed by means of the Glasgow Outcome Scale. IL-1β genotypes were determined from blood samples by standard methods.Findings. Fourteen of 25 (56%) patients with IL-1β +3953 allele 2 had an unfavourable outcome (dead, vegetative state or severe disability) compared with eight of 44 (18.1%) patients without IL-1β +3953 (p = 0.0004). Similarly, 20 of 28 (71.4%) patients with IL-1β −511 allele 2 had an unfavourable outcome compared with two of 41 (4.8%) patients without IL-1β −511 (p = 0.005). Patients who had a composite of IL-1β 2/2 or 1/2 genotype from both −511 and +3953 region of the chromosome 2 were more prone to have bad prognosis.Conclusion. Results of our study demonstrated that there might be a significant association between IL-1β gene polymorphism and outcome after HI, supporting the hypothesis of a genetically determined influence.
European Journal of Neurology | 2005
S. N. Yeni; Cigdem Ozkara; Nur Buyru; Onur Baykara; L. Hanoğlu; N. Karaağac; Emin Ozyurt; Mustafa Uzan
To evaluate the hypothetical link between apolipoprotein E (APOE) polymorphisms and mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE‐HS) and whether presence of APOE epsilon4 allele shortens the latent period between febrile seizures and epilepsy. A further interest is whether presence of APOE epsilon4 allele has an impact on severity of the disease. Forty‐seven patients with MTLE‐HS were compared with 62 controls. APOE polymorphisms were determined from lymphocytes by standard methods. Eight patients (17%) and 10 controls (16.1%) were demonstrated to have one APOE epsilon4 allele. There was not any statistically significant difference in APOE epsilon4 frequency between patients and controls (P > 0.05). There was not any difference statistically according to onset age of epilepsy and the presence of APOE epsilon4 allele within patient group. APOE epsilon4 polymorphisms did not influence the severity of epilepsy. APOE epsilon4 polymorphisms had no impact on outcome after surgery. Patients with bilateral memory deficits, bilateral hippocampal atrophy and with bilateral epileptiform interictal EEG transients, were independently compared with patients having unilateral features and there were not any statistically significant differences. This study has found no association between APOE epsilon4 polymorphisms and presentation of MTLE‐HS in a group of Turkish patients.
Tumor Biology | 2010
Onur Baykara; Ahmet Demirkaya; Kamil Kaynak; Serhan Tanju; Alper Toker; Nur Buyru
Lung cancer is the most common cause of cancer-related death worldwide and, like many other cancers, is affected by different genetic, epigenetic, and environmental factors. The WW domain-containing oxidoreductase (WWOX) gene is a tumor-suppressor gene located on chromosome 16q23.3–24.1, and it has been shown that it loses its function due to alterations in genetic and epigenetic mechanisms. The aim of this study is to investigate the relationship between lung cancer and WWOX gene. Tumor tissue samples, corresponding normal tissues, and blood samples obtained from 50 lung cancer patients were involved in the study. We analyzed methylation profile by methylation-specific PCR and mutations and polymorphisms by DNA sequencing. Methylation analysis showed that promoter hypermethylation was present in 38 of 50 (76%) patients. In addition, promoter region of WWOX gene of younger patients was more frequently methylated than older patients. Using DNA sequencing, we found four genetic alterations in WWOX gene. Two of them were germline mutations (Exon 4 and 7), and two of them were polymorphic (Exon 6 and 8). We found a new mutation in exon 7 (Arg-254→Cys) which has not been described previously. The changes in the short-chain dehydrogenase domain of the protein caused by the genetic alterations may affect the function of the gene. We conclude that hypermethylation of WWOX gene promoter region and mutations in the gene might be related to lung carcinogenesis.
Seizure-european Journal of Epilepsy | 2006
Cigdem Ozkara; Mustafa Uzan; Taner Tanriverdi; Onur Baykara; Burçak Ekinci; Naz Yeni; Ali Metin Kafadar; Nur Buyru
Summary Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is one of the most common medically intractable epilepsy syndromes and the pathogenesis of HS remains highly obscure. Recent studies demonstrated controversial results about the relationship between interleukin (IL) gene polymorphism and epilepsy in different ethnic groups. This correlation was investigated in Turkish patients with MTLE-HS. The allele distribution of IL-1α and IL-1β in 47 patients of Turkish ancestry was determined and compared with 99 ethnically matched control subjects. Analysis of genotype frequencies between patients and controls showed no statistically significant difference ( p >0.05). Our data suggest that IL-1α and IL-1β gene polymorphisms do not act as a strong susceptibility factor for MTLE-HS in individuals of Turkish ancestry.
Gene | 2014
Mutlu Niyazoglu; Onur Baykara; Arzuhan Koc; Pinar Aydoğdu; Ilhan Onaran; Fatma Dilek Dellal; Ertugrul Tasan; Gönül Sultuybek
BACKGROUND Graves Disease (GD) is an autoimmune disorder affected by an interaction of multiple genes such as Nuclear Factor-κB (NF-κB), Nuclear Factor-κB Inhibitor (NF-κBIA), Poly (ADP-ribose) polymerase-1 (PARP-1) and cytokines like Interleukin-1β (IL-1β), Interleukin-6 (IL-6) and Tumor Necrosis Factor-α (TNF-α) and mostly accompanied by an ocular disorder, Graves Ophthalmopathy (GO). We hypothesize that there is a relationship between GD, GO, polymorphisms of inflammatory related genes and their association with cytokines, which may play important roles in autoimmune and inflammatory processes. SUBJECTS AND METHODS To confirm our hypothesis, we studied the polymorphisms and cytokine levels of 120 patients with GD and GO using PCR-RFLP and ELISA methods, respectively. RESULTS We found that patients with GG genotype and carriers of G allele of PARP-1 G1672A polymorphism are at risk in the group having GD (p=0.0007) while having GA genotype may be protective against the disease. PARP-1 C410T polymorphism was found to be associated with GO by increasing the risk by 1.7 times (p=0.004). Another risk factor for development of GO was the polymorphism of del/ins of NFkB1 gene (p=0.032) that increases the risk by 39%. Levels of cytokines were also elevated in patients with GD, but no association was found between levels of cytokines and the development of GO as there was no change in levels of cytokines. CONCLUSIONS We suggest that, PARP-1 and NFkB1 gene polymorphisms may be risk factors for developing Graves Disease and Ophthalmopathy.
Journal of Cancer | 2015
Onur Baykara; Burak Bakir; Nur Buyru; Kamil Kaynak; Nejat Dalay
Chromosomal alterations are frequent events in lung carcinogenesis and usually display regions of focal amplification containing several overexpressed oncogenes. Although gains and losses of chromosomal loci have been reported copy number changes of the individual genes have not been analyzed in lung cancer. In this study 22 genes were analyzed by MLPA in tumors and matched normal tissue samples from 82 patients with non-small cell lung cancer. Gene amplifications were observed in 84% of the samples. Chromosome 8 was found to harbor the most frequent copy number alterations. The most frequently amplified genes were ZNF703, PRDM14 and MYC on chromosome 8 and the BIRC5 gene on chromosome 17. The frequency of deletions were much lower and the most frequently deleted gene was ADAM9. Amplification of the ZNF703, PRDM14 and MYC genes were highly correlated suggesting that the genes displaying high copy number changes on chromosome 8 collaborate during lung carcinogenesis.
Clinical and Applied Thrombosis-Hemostasis | 2009
M. Cem Ar; Onur Baykara; Ayse Nur Buyru; Zafer Baslar
About 10% of patients with severe hemophilia exhibit a milder clinical phenotype with less frequent bleeds. Among many other factors, coinheritance of prothrombotic mutations have been proposed to act as modulators of clinical severity in severe hemophilia. We conducted a study to evaluate the impact of 3 prothrombotic mutations (factor V Leiden, factor II, and methylenetetrahydrofolate reductase mutations) on clinical phenotype of patients with severe hemophilia in our institution. For this purpose we compared the average annual factor concentrate consumption between carriers and noncarriers of prothrombotic mutations. A total of 38 hemophilia A and B patients with factor levels less than 1 were recruited between October 2006 and October 2007. Prothrombotic mutations were detected in venous blood using polymerase chain reaction amplification technique. Eighteen patients (47%) carried no prothrombotic mutations. The remaining 20 patients (53%) were found to be carriers of either 1 or 2 mutations. Median age in both carrier and the non-carrier groups was 27 years. None of the patients in either group gave a history of thromboembolic event. Median annual factor concentrate consumptions in carriers and noncarriers were 610 ± 530 units/kg and 770 ± 670 units/kg, respectively (P = .203). Our results demonstrated no significant difference in annual factor concentrate consumption between carriers and noncarriers of prothrombotic mutations. Considering that average annual factor consumption is a surrogate indicator of clinical phenotype, we concluded that coinheritance of prothrombotic mutations was not associated with occurrence of different clinical phenotypes in severe hemophilia.
Experimental and Therapeutic Medicine | 2013
Onur Baykara; Merve Tansarikaya; Ahmet Demirkaya; Kamil Kaynak; Serhan Tanju; Alper Toker; Nur Buyru
Lung cancer, a major health problem affecting the epithelial lining of the lower respiratory tract, is considered to be one of the deadliest types of cancer in males and females and it is well-known that smoking is the chief cause of lung cancer. In addition to smoking and environmental factors, genetic susceptibility may also contribute to the development of lung cancer. Previous studies have shown that certain non-small cell lung cancer (NSCLC) patients harbor gain-of-function mutations in the epidermal growth factor receptor gene (EGFR). Phosphorylated EGFR triggers the activation of intracellular signal transduction pathways, including the RAS-MAPK, PI3K-Akt and STAT pathways. However, K-Ras gene point mutations in codons 12, 13 or 61 cause the inactivation of GTPase activity which results in overstimulation of cellular growth and gives rise to neoplastic development. Our aim was to investigate the presence and association of EGFR and K-Ras mutations in 50 primary NSCLC patients with a smoking history by using real-time PCR and sequencing. EGFR mutations were detected in four patients (8%). Two of these mutations were L858R mutations and the remaining two were deletion mutations spanning between codons 746 and 750. The L858R mutation was significantly associated with smoking status (P=0.003). K-Ras codon 12 and 61 mutations were also observed in four patients. However, no association was observed between K-Ras mutations and the tumor staging, gender, histology and smoking status of the patients.
Cancer Medicine | 2016
Onur Baykara; Nejat Dalay; Kamil Kaynak; Nur Buyru
Despite therapeutic advances, lung cancer remains one of the most common causes of cancer‐related deaths worldwide. The ZNF703 gene has been identified as the driver of the 8p11‐12 region and its amplification or overexpression has been associated with several types of cancers. It has also been shown that ZNF703 overexpression can activate the Akt/mTOR signaling pathway. The aim of our study was to investigate the role of the ZNF703 gene in association with Akt/mTOR activation in non‐small cell lung cancer (NSCLC). Expression levels in tumors and matched noncancerous tissue samples from 47 patients were analyzed by qRT‐PCR and the Akt phosphorylation levels were investigated by Western blotting. Our results show that ZNF703 is up‐regulated in 63.4% of NSCLC tumor samples. Althogh the correlation did not reach a statistically significant level Akt phosphorylation was increased in tumor tissues expressing high levels of ZNF703. The role of the ZNF703 gene has not been investigated in NSCLC. Our data show that ZNF703 may contribute to tumor development in NSCLC by activating the Akt/mTOR pathway.
International Journal of Medical Sciences | 2017
Onur Baykara; Nejat Dalay; Burak Bakir; Pelin Bulut; Kamil Kaynak; Nur Buyru
Background: Lung cancer is the leading cause of cancer deaths. The main risk factor is smoking but the risk is also associated with various genetic and epigenetic components in addition to environmental factors. Increases in the gene copy numbers due to chromosomal amplifications constitute a common mechanism for oncogene activation. A gene-dense region on chromosome 11q13 which harbors four core regions that are frequently amplified, has been associated with various types of cancer. The important cell cycle regulatory protein cyclin D1 (CCND1) is an essential driver of the first core region of the Chr11q13 amplicon. Deregulation of CCND1 has been associated with different kinds of human malignancies including lung cancer. The EMSY (c11orf30) gene has been proposed as the possible driver of the fourth core of the 11q13 amplicon and its amplification has been associated with breast and ovarian cancers. There is no report in the literature investigating the EMSY gene in lung cancer. Methods: In this study, expression levels of the EMSY and CCND1 genes were investigated in 85 patients with non small cell lung cancer by Real Time PCR. Results: Expression of the EMSY and CCND1 genes were increased in 56 (65.8%) and 50 (58.8%) of the patients, respectively. Both genes showed a higher expression in the tumors when compared to normal tissues. A strong correlation was present between the expression rates of both genes (p<0.001). Patients with adenocarcinoma had higher expression levels of both genes (p=0.02). Conclusion: We conclude that EMSY and CCND1 work in collaboration and contribute to the pathogenesis of lung cancer.