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Dive into the research topics where Deniz Ozel is active.

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Featured researches published by Deniz Ozel.


Cardiology Journal | 2012

Determination of right ventricular dysfunction using the speckle tracking echocardiography method in patients with obstructive sleep apnea.

Refik Emre Altekin; Mustafa Serkan Karakaş; Atakan Yanikoglu; Deniz Ozel; Omer Ozbudak; İbrahim Demir; Necmi Deger

BACKGROUND The speckle tracking echocardiography (STE) method shows the presence of right ventricular (RV) dysfunction before the advent of RV failure and pulmonary hypertension in patients with cardiopulmonary disease. We aimed to assess subclinical RV dysfunction in obstructive sleep apnea (OSA) using the STE method. METHOD Twenty-one healthy individuals and 58 OSA patients were included. According to severity as determined by the apnea-hypopnea index (AHI), OSA patients were examined in three groups: mild, moderate and severe. RV free wall was used in STE examination. RESULTS Right ventricle strain (ST %) and systolic strain rate (STR-S 1/s) were decreasing along with the disease severity (ST - healthy: -34.05 ± -4.29; mild: -31.4 ± -5.37; moderate: -22.75 ± -4.89; severe: -20.89 ± -5.59; p < 0.003; STR-S - healthy: -2.93 ± -0.64; mild: -2.85 ± -0.73; moderate: -2.06 ± -0.43; severe: -1.43 ± -0.33; p < 0.03). Correlated with the disease severity, the RV early diastolic strain rate (STR-E) was decreasing and the late diastolic strain rate was increasing (STR-E - healthy: 2.38 ± 0.63; mild: 2.32 ± 0.84; moderate: 1.66 ± 0.55; severe: 1 ± 0.54; p < 0.003; STR-A - healthy: 2.25 ± 0.33; mild: 2.32 ± 0.54; moderate: 2.79 ± 0.66; severe: 3.29 ± 0.54; p < 0.03). The STR-E/A ratio was found to be in a decreasing trend along with the disease severity (healthy: 1.08 ± 0.34; mild: 1.06 ± 0.46; moderate: 0.62 ± 0.22; severe: 0.34 ± 0.23; p < 0.03). CONCLUSIONS Subclinical RV dysfunction can be established in OSA patients even in the absence of pulmonary hypertension and pathologies which could have adverse effects on RV functions. In addition to the methods of conventional, Doppler and tissue Doppler echocardiography, using the STE method can determine RV dysfunction in the subclinical phase.


BMC Cancer | 2012

Tbx3 represses PTEN and is over-expressed in head and neck squamous cell carcinoma

Durmuş Burgucu; Kenan Guney; Duygu Sahinturk; Irem Hicran Ozbudak; Deniz Ozel; Gulay Ozbilim; Ugur Yavuzer

BackgroundDespite advances in diagnostic and treatment strategies, head and neck squamous cell cancer (HNSCC) constitutes one of the worst cancer types in terms of prognosis. PTEN is one of the tumour suppressors whose expression and/or activity have been found to be reduced in HNSCC, with rather low rates of mutations within the PTEN gene (6-8%). We reasoned that low expression levels of PTEN might be due to a transcriptional repression governed by an oncogene. Tbx2 and Tbx3, both of which are transcriptional repressors, have been found to be amplified or over-expressed in various cancer types. Thus, we hypothesize that Tbx3 may be over expressed in HNSCC and may repress PTEN, thus leading to cancer formation and/or progression.MethodsUsing immunohistochemistry and quantitative PCR (qPCR), protein and mRNA levels of PTEN and Tbx3 were identified in samples excised from cancerous and adjacent normal tissues from 33 patients who were diagnosed with HNSCC. In addition, HeLa and HEK cell lines were transfected with a Tbx3 expressing plasmid and endogenous PTEN mRNA and protein levels were determined via qPCR and flow cytometry. Transcription assays were performed to demonstrate effects of Tbx3 on PTEN promoter activity. Mann–Whitney, Spearman’s Correlation and Wilcoxon signed-rank tests were used to analyze the data.ResultsWe demonstrate that in HNSCC samples, Tbx3 mRNA levels are increased with respect to their normal tissue counterparts (p<0.001), whereas PTEN mRNA levels are significantly reduced in cancer tissues. Moreover, Tbx3 protein is also increased in HNSCC tissue sections. Over-expression of Tbx3 in HeLa and HEK cell lines causes reduction in endogenous PTEN mRNA and protein levels. In addition, transcription activity assays reveal that Tbx3 is capable of repressing both the basal and induced promoter activity of PTEN.ConclusionsWe show that Tbx3 is up-regulated in tissue samples of HNSCC patients and that Tbx3 represses PTEN transcription. Thus, our data not only reveals a new mechanism that may be important in cancer formation, but also suggests that Tbx3 can be used as a potential biomarker in cancer.


Pediatrics International | 2011

Early and long-term outcome after tracheostomy in children

Oguz Dursun; Deniz Ozel

Background:  Tracheostomy has become an increasingly important issue for children discharged with primary or secondary respiratory problems. Despite the known advantages, considerable controversy remains regarding the appropriate indications, timing, and results of tracheostomy, in the context of home care. The aims of this study were to retrospectively evaluate our experience with tracheostomy and to consider problems related to this procedure, both in the hospital and after discharge.


Journal of Clinical Research in Pediatric Endocrinology | 2013

CTLA-4 (+49A/G) Polymorphism and Type-1 Diabetes in Turkish Children

Fatih Çelmeli; Doga Turkkahraman; Deniz Ozel; Sema Akcurin; Olcay Yeğin

Objective: To evaluate the contribution of cytotoxic T-Iymphocyte antigen-4 (CTLA-4)+49A/G polymorphism to the susceptibility to type-1 diabetes (T1D) in Turkish children. Methods: A case-control study was designed to include 91 Turkish children with T1D and 99 healthy controls. CTLA-4 (+99A/G) gene polymorphism typing was done by PCR amplification followed by restriction fragment length polymorphism method. Results: The genotype and allele frequencies of the CTLA-4 (+99A/G) polymorphism in patients with T1D were not different from those in the controls (p>0.05). The allele frequency of G was 36.2% in patients with T1D, and 31.8% in controls (p>0.05). Additionally, this polymorphism was not associated with the clinical and laboratory characteristics of the patients with T1D (p>0.05). Conclusions: Our case-control study suggests that the CTLA-4 (+99A/G) gene polymorphism is not associated with T1D in the Turkish population. Conflict of interest:None declared.


Interactive Cardiovascular and Thoracic Surgery | 2010

Combination technique of tumescent anesthesia during endovenous laser therapy of saphenous vein insufficiency

Mehmet Erdem Memetoğlu; Serpil Kurtcan; Asim Kalkan; Deniz Ozel

OBJECTIVE This study aimed at evaluating the efficiency of applying tumescent anesthesia before an ablation procedure and continuously during endovenous laser treatment (EVLT) (combined tumescent technique) of saphenous vein insufficiency to reduce the patients pain and discomfort. METHODS Twenty-five patients with 31 duplex-confirmed great saphenous vein insufficiency underwent endovenous laser (940 nm) varicose vein treatment between December 2009 and April 2010. The patients were randomized in two groups. In group A (15 patients) tumescent anesthesia was used before the ablation procedure and in group B (10 patients) tumescent anesthesia was used before and continuously during the procedure. Patients were scheduled for a three-day examination after EVLT to assess the level of pain experienced. RESULTS According to the statistic analysis we observed that the mean level of pain score for the patients given classical tumescent anesthesia showed a higher level (P=0.003) compared with the patients given tumescent anesthesia in the combined procedure. CONCLUSION Combination technique of administering tumescent anesthesia before ablation and continuously during the EVLT procedure may be an alternative way to reduce the patients peroperative pain and discomfort.


Journal of Vascular Access | 2013

Peripherally inserted central venous catheters in critically ill premature neonates

Servet Ozkiraz; Zeynel Gokmen; Deniz Anuk Ince; Abdullah Baris Akcan; Hasan Kilicdag; Deniz Ozel; Ayşe Ecevit

Purpose To evaluate the safety of peripherally inserted central venous catheters (PICCs) and their complications in critically ill premature neonates. Methods A retrospective collection of data of infants with very low birth weight (VLBW) who underwent PICC placement over a 2-year period. Gestational age, birth weight (BW), sex, site of catheter placement, reason for catheter removal, duration of the catheter use, proven sepsis, type of the reported organism and the rate of complications were collected. The infants were classified into two groups according to BWs: Group 1–-VLBW infants (BW between 1,000 and 1,500 g) and Group 2–-BW <1,000 g (extremely low birth weight, ELBW group). Results During the study period, 90 VLBW infants were admitted to the neonatal intensive care unit. PICCs were attempted in 71 patients. A PICC was successfully inserted into 62 patients (87.3%). Totally, 68 PICCs were inserted into 62 infants. PICCs placed in either the upper or the lower extremity have no differences in complication rates. The median time of catheter insertion was 10 (1-22) days for Group 1 and 16 (1-47) days for Group 2 (p=0.001). The median duration of PICCs was 9 (2-18) and 12.0 (3-30) days, respectively (p=0.012). There were no significant differences between groups for the reasons for removal (p=0.859). Conclusions PICCs are convenient for the administration of long course antibiotics and parenteral nutrition for both VLBW and ELBW infants. The risk of catheter complications did not increase in ELBW infants. Although the technique of insertion is easy and using PICCs has many benefits, serious and fatal complications may occur in premature neonates in critical states.


International Journal of Cardiovascular Imaging | 2012

Assessment of subclinical left ventricular dysfunction in obstructive sleep apnea patients with speckle tracking echocardiography

Refik Emre Altekin; Atakan Yanikoglu; Ahmet Oguz Baktir; Mustafa Serkan Karakaş; Deniz Ozel; Aykut Cilli; Aytül Belgi Yıldırım; Hüseyin Yilmaz; Selim Yalçinkaya

In this study, our aim was to evaluate the LV (left ventricle) subclinical myocardial dysfunction using the two-dimensional speckle tracking echocardiography (2D-STE) method on obstructive sleep apnea (OSA) patients with preserved left ventricular ejection fraction (LVEF) and without any confounding disease that may result myocardial dysfunction. Twenty-one healthy individuals and 58 OSA patients were enrolled in the study. The patients were categorized into mild, moderate and severe OSA groups according to the apnea-hypopnea index (AHI). Conventional- and tissue Doppler echocardiography imagings were performed in all the individuals besides the 2D-STE. The longitudinal strain (S) and systolic strain rate (SRS) values decreased as the severity of disease increased from moderate towards severe OSA. The circumferential S and SRS values were observed to be lower in the severe OSA patients. Despite the increase in the radial S and SRS in moderate and mild OSA patients, these measurements decreased in those with severe OSA. Although the longitudinal, circumferential and radial early diastolic strain rates (SRE) decreased as the severity of disease increased form moderate to severe, the late diastolic strain rates (SRA) were observed to increase. In the early stages of OSA, longitudinal systolic LV dysfunction is detected in addition to the diastolic dysfunction. The circumferential mechanics of the LV deteriorate in the later stages of the OSA. Despite a compensatory increase in the radial LV function in the early stages of OSA, in later stages, the LV radial function also deteriorates. The assessment of the myocardial functions using the STE method in patients with OSA with preserved LVEF has the potential to detect the subclinical LV dysfunction and might provide useful information for risk stratification.


Platelets | 2014

Relationship between platelet indices and international normalized ratio in patients with non-valvular atrial fibrillation

Osman Ziya Arık; Bugra Ozkan; Rasim Kutlu; Hüseyin Karal; Durmuş Yıldıray Şahin; Onur Kaypaklı; Deniz Ozel; Murat Çaylı

Abstract Atrial fibrillation (AF) is the most common sustained arrhythmia and associated with adverse outcomes and increased risk for thromboembolic events. Warfarin is still the most extensively prescribed oral anticoagulant in AF to prevent ischemic complications. We aimed to determine the differences at platelet indices with warfarin usage layered by International Normalized Ratio (INR). A total of 250 patients with permanent non-valvular AF (mean age 70.2 ± 9.1; 153 female) were divided into two groups. Group 1 included 125 patients whose INR is between 2.0 and 3.0 (called as “effective”) and Group 2 included 125 patients whose INR is <2.0 (called as “ineffective”). Also 123 age- and sex-matched individuals in sinus rhythm enrolled as control group (Group 3). After physical and echocardiographic examination, complete blood counts and INR were studied. There was no statistically significant difference in age, sex, co-morbidities and medications, also hemoglobin, white blood cell and platelet counts among the groups. The CHA2DS2-VASc scores were similar between Groups 1 and 2. The mean platelet volume (MPV), platelet distribution width (PDW) and plateletcrit (PCT) were significantly higher in Group 2 than Groups 1 and 3 and similar between Groups 1 and 3. MPV was positively correlated with PDW and PCT and also inversely correlated with INR value and platelet count. On multivariate logistic regression analysis, MPV, PDW and PCT were independent predictors of ineffectiveness of INR. The results of this study showed that MPV, PDW and PCT are increased in patients with non-valvular AF without effective warfarin treatment. Warfarin usage adjusted by INR is associated with lower values of these platelet indices, even lower as the values of subjects in sinus rhythm. MPV, PDW and PCT are independent predictors of INR ineffectiveness and seem to be useful parameters for monitoring the effectiveness of warfarin treatment.


American Journal of Perinatology | 2012

Resistin—A Novel Feature in the Diagnosis of Sepsis in Premature Neonates

Zeynel Gokmen; Servet Ozkiraz; Sevsen Kulaksizoglu; Hasan Kilicdag; Deniz Ozel; Ayşe Ecevit; Aylin Tarcan

OBJECTIVE To evaluate the diagnostic potential of resistin in sepsis and to compare results with C-reactive protein (CRP) in infants < 32 weeks of gestation. STUDY DESIGN A total of 64 infants were prospectively included in the study. Blood samples were collected for basal CRP and resistin within the first hour of life. When sepsis was suspected, samples were collected for CRP and resistin before the treatment was started (pretreatment CRP and resistin). On the third day of sepsis, CRP and resistin levels were measured for evaluating the treatment response (follow-up CRP and follow-up resistin). Culture-proven septic patients were divided into groups according to early or late-onset sepsis (EOS and LOS) and gram-negative or gram-positive sepsis (GNS and GPS). RESULTS Pretreatment and follow-up resistin levels were significantly higher than basal resistin levels in both EOS and LOS groups (p < 0.01), with a positive correlation with CRP levels. To predict the GNS and GPS area under curve, values of pretreatment CRP and resistin were 0.714 and 0.984, respectively (p = 0.039). CONCLUSION Resistin had a superior potential to that of CRP in the diagnosis of sepsis in preterm infants. Resistin may be used as an early marker for sepsis in premature infants.


Journal of The Saudi Heart Association | 2016

Red cell distribution width and neutrophil-to-lymphocyte ratio predict left ventricular dysfunction in acute anterior ST-segment elevation myocardial infarction

Mustafa Serkan Karakaş; Necmettin Korucuk; Veysel Tosun; Refik Emre Altekin; Fatih Koç; Sinan Cemgil Özbek; Deniz Ozel; Cengiz Ermis

Objectives Red cell distribution width (RDW) and neutrophil-to-lymphocyte ratio (NLR) are the two markers used to determine risk of mortality and adverse cardiovascular outcomes in patients with acute myocardial infarction. The relationship between RDW, NLR, and left ventricular (LV) systolic functions has not been reported. In this report, we aimed to investigate the relationship between RDW, NLR, and LV systolic function in anterior ST-segment elevation myocardial infarction (STEMI) patients who underwent primary percutaneous coronary intervention (PCI). Methods RDW and NLR were measured on admission in 106 STEMI patients treated with primary PCI. Patients were divided into two groups according to left ventricular ejection fraction (LVEF), as Group I (systolic dysfunction, LVEF <50%) and Group II (preserved global left ventricle systolic function, LVEF ⩾50%). The first group included 47 patients and the second group included 59 patients. Results Mean RDW and NLR were significantly higher in Group I compared to Group II [13.7 ± 0.9% vs. 13.4 ± 0.7%, p = 0.03 and 5.86 (range, 0.66–40.50) vs. 2.75 (range, 0.51–39.39), p = 0.013, respectively]. Conclusion Increased RDW and NLR on admission, in anterior STEMI patients treated with primary PCI are associated with LV systolic dysfunction.

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Asim Kalkan

Recep Tayyip Erdoğan University

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