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Dive into the research topics where Yüksel Bek is active.

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Featured researches published by Yüksel Bek.


European Journal of Radiology | 2003

Unbiased estimation of the liver volume by the Cavalieri principle using magnetic resonance images

Bunyamin Sahin; Mehmet Emirzeoglu; Ahmet Uzun; Lutfi Incesu; Yüksel Bek; Sait Bilgic; Süleyman Kaplan

OBJECTIVE It is often useful to know the exact volume of the liver, such as in monitoring the effects of a disease, treatment, dieting regime, training program or surgical application. Some non-invasive methodologies have been previously described which estimate the volume of the liver. However, these preliminary techniques need special software or skilled performers and they are not ideal for daily use in clinical practice. Here, we describe a simple, accurate and practical technique for estimating liver volume without changing the routine magnetic resonance imaging scanning procedure. MATERIALS AND METHODS In this study, five normal livers, obtained from cadavers, were scanned by 0.5 T MR machine, in horizontal and sagittal planes. The consecutive sections, in 10 mm thickness, were used to estimate the whole volume of the liver by means of the Cavalieri principle. The volume estimations were done by three different performers to evaluate the reproducibility. RESULTS There are no statistical differences between the performers and real liver volumes (P > 0.05). There is also high correlation between the estimates of performers and the real liver volume (r = 0.993). CONCLUSION We conclude that the combination of MR imaging with the Cavalieri principle is a non-invasive, direct and unbiased technique that can be safely applied to estimate liver volume with a very moderate workload per individual.


Joint Bone Spine | 2009

Effects of two exercise interventions on pulmonary functions in the patients with ankylosing spondylitis.

Dilek Durmus; Gamze Alayli; Oguz Uzun; Berna Tander; Ferhan Canturk; Yüksel Bek; Levent Erkan

OBJECTIVE The aim of this study was to evaluate the impact of two different home-based daily exercise programs on pulmonary functions in the patients with ankylosing spondylitis (AS). METHODS Fifty-one patients with AS were distributed into three groups. Group 1 (n=19) was given a conventional exercise regimen. Group 2 (n=19) received exercises based on the Global Posture Reeducation (GPR) method. Group 3 (n=13) was accepted as the control group. Patients were assessed according to pain, functional capacity (The Bath Ankylosing Spondylitis Functional Index - BASFI), disease activity (The Bath Ankylosing Spondylitis Disease Activity Index - BASDAI), chest expansion, pulmonary function parameters, and 6-min walk distance (6MWD) test. RESULTS Although there were significant improvements for BASDAI and BASFI scores in all groups, significant improvements in the VAS pain, chest expansion, pulmonary function parameters and 6MWD test were observed in the exercise groups. The improvements in pain, functional capacity, disease activity, chest expansion, pulmonary function parameters and 6MWD test were better in the exercise groups than in the control group. The GPR method resulted in greater improvements than the conventional exercise program in specific pulmonary function parameters like forced vital capacity, forced expiratory volume in 1s, and peak expiratory flow parameters. CONCLUSION Both exercises are efficient in improving pulmonary functions. Since the improvements in pulmonary function tests were greater in the patients who performed the exercise according to GPR method, motivated patients should be encouraged to perform this exercise program.


Clinical Rheumatology | 2007

T helper 1 type cytokines polymorphisms: association with susceptibility to Behçet’s disease

Gamze Alayli; Fatma Aydin; Ahmet Yilmaz Coban; Yuksel Sullu; Ferhan Canturk; Yüksel Bek; Belma Durupinar; Tayyar Cantürk

The pathogenesis of Behçet’s disease (BD) is not fully understood and immunological abnormalities and genetic factors have been investigated. Because serum concentrations of mainly T helper 1 (Th1) type cells have been reported to be increased in BD, we aimed to investigate whether certain cytokine polymorphisms might represent a risk factor for developing BD. We genotyped 80 patients with BD and 105 healthy controls for interleukin (IL)-1 α (T/C −889), IL-1 β (C/T −511, T/C +3962), IL-1R (C/T pst11970), IL-1RA (T/C mspa111100), IL-2 (T/G −330), IL-12 (C/A −1188), interferon (IFN)-γ (A/T UTR 5644), and TNF-α (G/A −238) polymorphisms. Analyses of cytokine polymorphisms were performed with PCR-SSP. The genotype and allele frequencies of the patients and controls were compared and the association between the polymorphisms of the cytokines with the clinical findings was investigated. Genotype distribution showed significant differences between the patients and the controls for the IL-1 α −889, IL-1 β −511, IL-1 β +3962, IL-1R, IL-12, IFN- γ, and TNF-α cytokines. We didn’t observe significant difference in genotypic frequencies of IL-1RA and IL-2 in our study. Comparison of the IL-1 α −889, IL 1 β −511, and IL 1 β +3962 genotype frequencies showed significant increase in CC genotype between the patients and the controls. The individuals with IL-1R TT polymorphism had a higher risk for BD compared to patients with CT/CC polymorphism. Comparison of IL-12, IFN- γ, and TNF-α, genotype frequencies showed significant increase in CA, AA, and AA genotypes between the patients and controls, respectively. The frequencies of genotypes according to the clinical features of the patients with BD did not show a significant difference (p > 0.05). Our study suggests that development of BD might be determined by various cytokine gene polymorphisms. However, further studies on larger numbers of cases are needed before definite conclusions can be drawn.


Pediatric Dermatology | 2011

Environmental risk factors in pediatric psoriasis: a multicenter case-control study.

Müge G. Özden; Nilgün S. Tekin; Mehmet A. Gürer; Devrim Akdemir; Çiğdem Doğramacı; Serap Utaş; Ayşe Akman; Sibel E. Evans; Sevgi Bahadır; Serap Öztürkcan; Guliz Ikizoglu; Neslihan Şendur; Osman Köse; Yüksel Bek; Savaş Yaylı; M. Tayyar Cantürk; Ahmet Y. Turanl

Abstract:  To analyze the effect of possible risk factors, including breastfeeding, on the development of childhood‐onset psoriasis, a multicenter case‐control study with prospective collection of data was performed. Using a standard questionnaire, personal and specific variables including family history of psoriasis, maternal and environmental tobacco smoke exposure, body mass index (BMI), exclusive and partial breastfeeding for at least 3 and 12 months, cow’s milk intake before 1 year, birth delivery method, and stressful life events were collected during 2009 from 537 patients with psoriasis and 511 controls younger than 18. Overall, patients more frequently reported exposure to environmental tobacco smoke at home and stressful life events in the year preceding the diagnosis than controls. The odds ratios (OR) for smoking and stressful life events were 2.90 (95% confidence interval [CI] = 2.27–3.78) and 2.94 (95% CI = 2.28–3.79), respectively. In addition, children with psoriasis were more likely to have a higher BMI (>26) than controls (OR = 2.52; 95% CI = 1.42–4.49). High BMI, environmental tobacco smoke exposure at home, and stressful life events may influence the development of pediatric psoriasis.


Archives of Oral Biology | 2009

Evaluation of the relationship between passive smoking and salivary electrolytes, protein, secretory IgA, sialic acid and amylase in young children

Aysun Avşar; Özge Darka; Ebru Hazar Bodrumlu; Yüksel Bek

OBJECTIVE To evaluate the relationship between passive smoking as determined by salivary cotinine levels and salivary electrolytes, protein, secretory IgA, sialic acid and amylase in children. DESIGN Saliva was collected from 90 passive smoker (PS) subjects (the study group) and 90 healthy age-matched children (the control group). The study group was divided into three subgroups according the number of cigarettes smoked. Socio-economic status, dental and dietary habits were recorded by questionnaire. Stimulated salivary calcium (Ca), phosphate (P), sodium (Na), potassium (P), total protein, amylase activity, sialic acid level, secretory IgA concentration and cotinine level were analysed. All data were analysed using SPSS, version 13.0. RESULTS Socio-economic status, dental and dietary habits were similar between the two groups. The salivary electrolytes concentrations did not reveal significant difference between the two groups (p>0.05). The mean cotinine levels of PS children were 1.58+/-4.3 ng/mL. The salivary concentrations of protein were similar between the two groups (p>0.05). The salivary secretory IgA concentration was significantly lower in the PS group than controls. The sialic acid level and amylase activity in PS group were found significantly higher compared with the controls (p<0.05). No difference was observed for all these parameters with sex (p>0.05). When saliva samples were analysed for output, the sialic acid level and amylase activity increased significantly in PS subjects (p<0.05). Further, the output of secretory IgA concentration was found significantly lower compared with the controls (p<0.05). CONCLUSION In conclusion, we show that passive smoking was associated with a decrease in secretory IgA concentration, whereas with increase in amylase activity and sialic acid level of stimulated whole saliva in young children.


Archives of Oral Biology | 2008

Association of passive smoking with caries and related salivary biomarkers in young children

Aysun Avşar; Özge Darka; B. Topaloğlu; Yüksel Bek

OBJECTIVE To investigate the association between passive smoking, as determined by salivary cotinine level, and caries, salivary pH, buffering capacity, flow rate and microbiological counts in young children. DESIGN Ninety passive smokers (PS) with a mean age of 5.02 years and 90 healthy age-matched controls were included in this study. Family income, smoking habits of household members, parental education levels, childs tooth-brushing habit and childs daily dietary sugar exposure were recorded by questionnaire. Three categories were formed with respect to the number of cigarettes smoked. A dmft score was calculated according to the criteria recommended by the World Health Organization. The children were also investigated for stimulated salivary cotinine level, pH, flow rate, buffering capacity and salivary Streptococcus mutans and lactobacilli colonisation. RESULTS There were no significant differences in tooth-brushing habit, sugar exposure, family income and parental education levels between the two groups (P>0.05). The mean cotinine level of the PS subjects was 1.58+/-4.3ng/ml. The dmft scores, and salivary S. mutans and lactobacilli colonisation in PS children were significantly higher than in the control subjects (P<0.05). Statistically significant decreases in salivary pH, flow rate and buffering capacity were found in the PS subjects (P<0.05). CONCLUSION PS children are at increased risk of caries compared with control subjects.


Clinical Anatomy | 2008

Dependence of computed tomography volume measurements upon section thickness: An application to human dry skulls

Bunyamin Sahin; Michael Mazonakis; Hüseyin Akan; Süleyman Kaplan; Yüksel Bek

Estimation of intracranial volume (ICV) using computed tomography (CT) scans has previously been described. However, we were not able to identify a gold standard study that analyzed the effect of section thickness on the estimation of ICV. Therefore, we conducted the present study, scanning five dry skulls in the coronal and axial planes using a multislice CT machine (Toshiba TSX‐101A, Aquilion 16 Slice, Tochigi, Japan). Consecutive sections of variable thicknesses of 2, 3, 5, 7, and 10 mm, respectively, were used to estimate ICV by means of the planimetry method of the Cavalieri principle. All estimations were done by the same observer. However, the estimated volumes did not concur with the actual volumes of the skulls as determined by the fluid displacement technique (P < 0.05). In fact, results revealed that the section thicknesses created over‐ or under‐projection effects for the estimated volumes. The results were analyzed to reveal the deviation principles of the estimates based on section thickness. Prediction formulas were calculated to estimate the deviation percentage of the ICV depending on section thickness and section plane. Ultimately, the results showed that the effect of section thickness on ICV estimates could not be overlooked, but that the values obtained could be corrected using the proposed prediction formulas presented in this study. Clin. Anat. 21:479–485, 2008.


DNA and Cell Biology | 2011

Tumor necrosis factor alpha and beta and interferon gamma gene polymorphisms in Turkish breast cancer patients.

Nevin Karakus; Nurten Kara; Ali Naki Ulusoy; Cihangir Özaslan; Yüksel Bek

Cytokine genes are important for researching cancer predisposition to cancers that elicit anti-tumor immune response. In this study, we investigated the association between breast cancer and tumor necrosis factor alpha (TNF-α) -308 (G>A), TNF-β +252 (A>G), and interferon gamma (IFN-γ) +874 (T>A) gene polymorphisms in a Turkish population. This study involved 204 female breast cancer patients and 204 healthy female controls. Genomic DNA was extracted from EDTA-preserved peripheral venous blood of patients and controls by a salting-out method and analyzed by polymerase chain reaction, allele-specific oligonucleotide polymerase chain reaction, and restriction fragment length polymorphism. TNF-α -308 genotype was found to have no effect on breast cancer susceptibility. However, there were statistically significant differences between the genotype frequencies of patients and controls for TNF-β polymorphism (p = 0.016) and the allele and genotype frequencies for the IFN-γ polymorphism (p = 0.0312 and p = 0.001, respectively). In the composite genotype analysis, the TNF-α/β GAAG composite genotype (p = 0.0424), the TNF-α/IFN-γ GGTT and GATT composite genotypes (p = 0.0296 and p = 0.0129, respectively), the TNF-β/IFN-γ AGTT composite genotype (p = 0.0003), and the TNF-α/β/IFN-γ GGAGTT and GAAGTT composite genotypes (p = 0.0437 and p = 0.0038, respectively) were estimated to have a protective effect against breast cancer. However, the TNF-α/IFN-γ GGTA composite genotype is a risk factor for breast cancer (p = 0.0156). In conclusion, TNF-β +252GG genotype was found more frequent in Turkish breast cancer patients than controls and IFN-γ TA+AA genotypes were estimated to increase breast cancer risk significantly in Turkish population.


Journal of Intensive Care Medicine | 2005

In acute organophosphate poisoning, the efficacy of hemoperfusion on clinical status and mortality.

Levent Altintop; Dursun Aygün; Havva Sahin; Zahide Doganay; Hakan Güven; Yüksel Bek; Tekin Akpolat

The aims of this study were to report experience in patients with organophosphate poisoning (OPP) and to discuss the potential role for hemoperfusion (HP) in the management of severe OPP. At the emergency service of a university hospital, 52 patients with acute OPP were included in this retrospective study. The patients were divided into 2 groups (Group 1, severe poisoning, n = 25; and Group 2, mild poisoning, n = 27). All patients with mild OPP survived. Seven patients (28%) of the 25 with severe OPP died. This study supports previous data documenting that HP is unnecessary in the management of mild OPP. Although there was not a control group (severe poisoning without HP treatment) in this study, experience suggests that HP can be useful in severe cases. Reports from centers having experience with severe OPP can help clarify this controversial issue. Randomized controlled (prospective) studies investigating the possible beneficial effects of HP on patient survival in patients with severe OPP with control group are needed.


Clinical and Experimental Dermatology | 2009

Axillary hair removal with 1064‐nm Nd:YAG laser increases sweat production

Fatma Aydin; G. S. Pancar; Nilgun Senturk; Yüksel Bek; Esra Pancar Yuksel; Tayyar Cantürk; Ahmet Yasar Turanli

Background.  Laser‐assisted hair removal has become a popular treatment for eradication of body hair. Many studies have been published concerning the safety and efficacy of several laser systems. Adverse events are hyperpigmentation, hypopigmentation, erythema, oedema, scarring, pain and blistering. Changes in sweating have not previously been reported.

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Fatma Aydin

Ondokuz Mayıs University

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Tayyar Cantürk

Ondokuz Mayıs University

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Nilgun Senturk

Ondokuz Mayıs University

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Bunyamin Sahin

Ondokuz Mayıs University

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Ferhan Canturk

Ondokuz Mayıs University

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Nurten Kara

Ondokuz Mayıs University

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Dilek Durmus

Ondokuz Mayıs University

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