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Dive into the research topics where Nurullah Akkoc is active.

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Featured researches published by Nurullah Akkoc.


Annals of the Rheumatic Diseases | 2009

The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection

Martin Rudwaleit; D. van der Heijde; R. Landewé; Joachim Listing; Nurullah Akkoc; J Brandt; J. Braun; Chung Tei Chou; Eduardo Collantes-Estevez; Maxime Dougados; Feng Huang; Jieruo Gu; M A Khan; Yesim Kirazli; Walter P. Maksymowych; Herman Mielants; Inge Juul Sørensen; Salih Ozgocmen; E. Roussou; R. Valle-Oñate; Ulrich Weber; James Cheng-Chung Wei; J. Sieper

Objective: To validate and refine two sets of candidate criteria for the classification/diagnosis of axial spondyloarthritis (SpA). Methods: All Assessment of SpondyloArthritis international Society (ASAS) members were invited to include consecutively new patients with chronic (⩾3 months) back pain of unknown origin that began before 45 years of age. The candidate criteria were first tested in the entire cohort of 649 patients from 25 centres, and then refined in a random selection of 40% of cases and thereafter validated in the remaining 60%. Results: Upon diagnostic work-up, axial SpA was diagnosed in 60.2% of the cohort. Of these, 70% did not fulfil modified New York criteria and, therefore, were classified as having “non-radiographic” axial SpA. Refinement of the candidate criteria resulted in new ASAS classification criteria that are defined as: the presence of sacroiliitis by radiography or by magnetic resonance imaging (MRI) plus at least one SpA feature (“imaging arm”) or the presence of HLA-B27 plus at least two SpA features (“clinical arm”). The sensitivity and specificity of the entire set of the new criteria were 82.9% and 84.4%, and for the imaging arm alone 66.2% and 97.3%, respectively. The specificity of the new criteria was much better than that of the European Spondylarthropathy Study Group criteria modified for MRI (sensitivity 85.1%, specificity 65.1%) and slightly better than that of the modified Amor criteria (sensitivity 82.9, specificity 77.5%). Conclusion: The new ASAS classification criteria for axial SpA can reliably classify patients for clinical studies and may help rheumatologists in clinical practice in diagnosing axial SpA in those with chronic back pain. Trial registration number: NCT00328068.


Annals of the Rheumatic Diseases | 2011

The Assessment of SpondyloArthritis international Society classification criteria for peripheral spondyloarthritis and for spondyloarthritis in general

Martin Rudwaleit; D. van der Heijde; R. Landewé; Nurullah Akkoc; J Brandt; Chung Tei Chou; M. Dougados; Feng Huang; Jieruo Gu; Yesim Kirazli; F. van den Bosch; Ignazio Olivieri; E. Roussou; S. Scarpato; Inge Juul Sørensen; R. Valle-Oñate; Ulrich Weber; James Cheng-Chung Wei; J. Sieper

Objective To evaluate new classification criteria for peripheral spondyloarthritis (SpA) in patients with SpA with peripheral manifestations only. Methods In this Assessment of SpondyloArthritis international Society (ASAS) study, two prespecified sets of criteria were compared against the European Spondylarthropathy Study Group (ESSG) and Amor criteria in newly referred consecutive patients with undiagnosed peripheral arthritis, and/or enthesitis, and/or dactylitis that usually began before 45 years of age. The clinical diagnosis (SpA vs no SpA) made by the ASAS rheumatologist served as reference standard. Results In all, 24 ASAS centres included 266 patients, with a final diagnosis of SpA being made in 66.2%. After adjustments a final set of criteria showed the best balance between sensitivity (77.8%) and specificity (82.9%): arthritis and/or enthesitis and/or dactylitis plus (A) one or more of the following parameters: psoriasis, inflammatory bowel disease, preceding infection, human leucocyte antigen B27, uveitis, sacroiliitis on imaging, or (B) two or more other parameters: arthritis, enthesitis, dactylitis, inflammatory back pain in the past, family history of SpA. The new criteria performed better than modified versions of the ESSG (sensitivity 62.5%, specificity 81.1%) and the Amor criteria (sensitivity 39.8%, specificity 97.8%), particularly regarding sensitivity. In the entire ASAS population of 975 patients the combined use of ASAS criteria for axial SpA and ASAS criteria for peripheral SpA also had a better balance (sensitivity 79.5%, specificity 83.3%) than the modified ESSG (sensitivity 79.1%, specificity 68.8%) and Amor criteria (sensitivity 67.5%, specificity 86.7%), respectively. Conclusions The new ASAS classification criteria for peripheral SpA performed well in patients presenting with peripheral arthritis, enthesitis and/or dactylitis.


Nature Genetics | 2002

AGPAT2 is mutated in congenital generalized lipodystrophy linked to chromosome 9q34.

Anil K. Agarwal; Elif Arioglu; Salome de Almeida; Nurullah Akkoc; Simeon I. Taylor; Anne M. Bowcock; Robert Barnes; Abhimanyu Garg

Congenital generalized lipodystrophy is an autosomal recessive disorder characterized by marked paucity of adipose tissue, extreme insulin resistance, hypertriglyceridemia, hepatic steatosis and early onset of diabetes. We report several different mutations of the gene (AGPAT2) encoding 1-acylglycerol-3-phosphate O-acyltransferase 2 in 20 affected individuals from 11 pedigrees of diverse ethnicities showing linkage to chromosome 9q34. The AGPAT2 enzyme catalyzes the acylation of lysophosphatidic acid to form phosphatidic acid, a key intermediate in the biosynthesis of triacylglycerol and glycerophospholipids. AGPAT2 mRNA is highly expressed in adipose tissue. We conclude that mutations in AGPAT2 may cause congenital generalized lipodystrophy by inhibiting triacylglycerol synthesis and storage in adipocytes.


American Journal of Human Genetics | 2013

Identification of multiple genetic susceptibility loci in Takayasu arteritis

Güher Saruhan-Direskeneli; Travis Hughes; Kenan Aksu; Gokhan Keser; Patrick Coit; Sibel Zehra Aydin; Fatma Alibaz-Oner; Sevil Kamali; Murat Inanc; Simon Carette; Gary S. Hoffman; Servet Akar; Fatos Onen; Nurullah Akkoc; Nader Khalidi; Curry L. Koening; Omer Karadag; Sedat Kiraz; Carol A. Langford; Carol A. McAlear; Zeynep Ozbalkan; Aşkın Ateş; Yasar Karaaslan; Kathleen Maksimowicz-McKinnon; Paul A. Monach; Huseyin T. E. Ozer; Emire Seyahi; Izzet Fresko; Ayse Cefle; Philip Seo

Takayasu arteritis is a rare inflammatory disease of large arteries. The etiology of Takayasu arteritis remains poorly understood, but genetic contribution to the disease pathogenesis is supported by the genetic association with HLA-B*52. We genotyped ~200,000 genetic variants in two ethnically divergent Takayasu arteritis cohorts from Turkey and North America by using a custom-designed genotyping platform (Immunochip). Additional genetic variants and the classical HLA alleles were imputed and analyzed. We identified and confirmed two independent susceptibility loci within the HLA region (r(2) < 0.2): HLA-B/MICA (rs12524487, OR = 3.29, p = 5.57 × 10(-16)) and HLA-DQB1/HLA-DRB1 (rs113452171, OR = 2.34, p = 3.74 × 10(-9); and rs189754752, OR = 2.47, p = 4.22 × 10(-9)). In addition, we identified and confirmed a genetic association between Takayasu arteritis and the FCGR2A/FCGR3A locus on chromosome 1 (rs10919543, OR = 1.81, p = 5.89 × 10(-12)). The risk allele in this locus results in increased mRNA expression of FCGR2A. We also established the genetic association between IL12B and Takayasu arteritis (rs56167332, OR = 1.54, p = 2.18 × 10(-8)).


Rheumatology | 2010

Assessment of disease activity and progression in Takayasu’s arteritis with Disease Extent Index-Takayasu

Sibel Z. Aydin; Neslihan Yilmaz; Servet Akar; Kenan Aksu; Sevil Kamalı; Eftal Yucel; Ömer Karadağ; Muge Bicakcigil; Huseyin Ozer; Sedat Kiraz; Fatos Onen; Murat İnanç; Gokhan Keser; Nurullah Akkoc; Haner Direskeneli

OBJECTIVE Disease Extent Index-Takayasu (DEI.Tak) is a new index developed for the follow-up of Takayasus arteritis (TA), assessing only clinical findings without the requirement of imaging. We investigated the effectiveness of DEI.Tak in assessing disease activity and progression by comparing with physicians global assessment (PGA) and active disease criteria defined by Kerr et al. METHODS The initial DEI.Tak forms were filled in for 145 TA patients cross-sectionally to detect the baseline damage and after 29.8 (31) months (n = 105, 144 visits) only by including the new/worsening symptoms within the past 6 months. RESULTS At baseline, all patients had a DEI.Tak >0 [mean (s.d.): 7.6 (4.2)]. At this evaluation, 62% of the patients had active, 16.2% had persistent and 21.8% had inactive disease according to the PGA. At follow-up, in 69% of the patients the DEI.Tak score was 0. However, 14% of them were accepted as having active and 17% persistent disease according to PGA. In contrast, 18% with a DEI.Tak  ≥  1 were inactive according to PGA. Patients with active or persistent disease with PGA had higher DEI.Tak compared with inactives [1.3 (1.9), 1 (1.3) vs 0.2 (0.6), respectively; P < 0.001]. According to Kerrs criteria 27% were active. The total agreement between DEI.Tak and Kerrs criteria was 94% (κ = 0.85). Compared with PGA, Kerrs criteria had a total agreement of 74% and DEI.Tak 68%. CONCLUSION During follow-up, most TA patients showed no clinical activity with DEI-Tak. Although the agreement between Kerrs criteria and DEI.Tak seemed very good, using Kerrs criteria instead of DEI.Tak increased the consistency with PGA, which could be explained by the influence of imaging data and acute-phase reactant levels on the physicians decisions.


BMC Musculoskeletal Disorders | 2012

Biomarkers and cytokines of bone turnover: extensive evaluation in a cohort of patients with ankylosing spondylitis

Ali Taylan; Ismail Sari; Baris Akinci; Safak Bilge; Didem Kozaci; Servet Akar; Ayfer Colak; Hulya Yalcin; Necati Gunay; Nurullah Akkoc

BackgroundAnkylosing spondylitis (AS) is a chronic inflammatory disease of spine and sacroiliac joints; it is characterized by new bone formation, and the disease processes can be accompanied by osteoporosis. In the present study, we investigated changes in bone mineral density (BMD) and in the levels of various bone turnover-related biomarkers and cytokines in a cohort of AS patients, with regard to clinical parameters, disease activity, and treatment regimen.Methods55 AS patients and 33 healthy controls included in the study. Spinal mobility was assessed by the Bath Ankylosing Spondylitis Metrology Index (BASMI), and radiologic changes were scored by the Bath Ankylosing Spondylitis Radiologic Index (BASRI). Patients were also evaluated with the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). Bone mineral density (BMD) assessed by dual energy X-ray absorptiometry. Various biomarkers and cytokines of bone turnover including osteoprotegerin (OPG), serum band 5 tartrate-resistant acid phosphatase (TRAP-5), soluble receptor activator of nuclear factor kappa-B ligand (sRANKL), secreted frizzled-related protein 1 (sFRP-1), Dickkopf-related protein 1 (DKK-1), and sclerostin were studied.ResultsThe levels of TRAP-5, NTX, sRANKL, sclerostin, sFRP-1, DKK-1, and IFNγ, were similar between the patients and controls (p > 0.05), while BMD of femoral neck, and OPG levels were significantly lower in AS patients (p < 0.05). In a subgroup analysis, patients with active disease had significantly higher concentrations of OPG compared with the inactive group. Rest of the biomarkers and cytokines of bone turnover were similar between the active and inactive disease groups. Subgroup analysis of patients receiving anti-TNFα agents and conventional therapy revealed that OPG concentrations were significantly lower in the patients receiving biological drugs, while BAP and DKK-1 were significantly higher in the patients treated with conventional agents.ConclusionsIn this cross-sectional study we showed that OPG levels were significantly lower in AS patients compared to healthy subjects. On the other hand, the levels of wingless (Wnt) signal pathway inhibitors seem not altered. Ectopic bone formation in AS may be related to dysfunction of these molecules at the cellular level.


The American Journal of Gastroenterology | 2007

Irritable bowel syndrome in persons who acquired trichinellosis.

Müjde Soytürk; Hale Akpinar; Oguz Gurler; E. Pozio; Ismail Sari; Servet Akar; Mesut Akarsu; Merih Birlik; Fatos Onen; Nurullah Akkoc

BACKGROUND AND AIM:The postinfectious irritable bowel syndrome (PI-IBS) frequently follows bacterial infections. Since people suffering from PI-IBS and Trichinella spiralis–infected mice develop similar findings, this animal model has been successfully used for PI-IBS studies; however, IBS has never been studied in humans after trichinellosis. The aim of this study was to evaluate the IBS symptoms in people who had acquired trichinellosis.PATIENTS AND METHODS:A large outbreak of trichinellosis caused by Trichinella britovi occurred in Izmir, Turkey, in 2003–2004. The diagnosis of trichinellosis was confirmed by serology and muscle biopsy. After clinical and laboratory evaluations, 72 patients (38 women, 34 men, mean age 33.2 ± 10.4 yr) with trichinellosis without preexisting IBS were enrolled in the study. Noninfected people (N = 27) were used as control group. A questionnaire was developed to assess symptoms of IBS and alarm symptoms. The first interview was done face-to-face. After 2, 4, and 6 months of the first interview, the questionnaire was readministered to the patients without any information on the occurrence of a previous trichinellosis syndrome, while it was applied after a year only to the patients who had suffered IBS symptoms according to at least one of the previous interviews.RESULTS:According to Rome II criteria, PI-IBS developed in 10 of 72 (13.9%) people with confirmed trichinellosis, who had no preexisting IBS. The rate of PI-IBS was 13.9% and 13.9% at the 4th and 6th months, respectively. The symptoms of PI-IBS persisted in five of them up to 1 yr. People without trichinellosis did not develop any IBS symptoms.CONCLUSIONS:This is the first report of the development of PI-IBS after T. britovi. Consequently, IBS can be considered as a secondary syndrome induced by trichinellosis.


Clinical Rheumatology | 2007

Body composition, insulin, and leptin levels in patients with ankylosing spondylitis

Ismail Sari; Tevfik Demir; Leyla Didem Kozaci; Servet Akar; Tulay Kavak; Merih Birlik; Fatos Onen; Nurullah Akkoc

The aim of this study was to compare the effect of chronic inflammation on insulin resistance, serum leptin levels, and body composition (BC) in patients with ankylosing spondylitis (AS) and healthy controls. Twenty-eight AS patients and 17 healthy controls were included in this study. Subjects with hypertension, diabetes, hyperlipidemia, and obesity were excluded. Acute phase reactants and serum levels of glucose, insulin, lipids, and leptin were studied. BC was determined anthropometrically and by foot-to-foot body fat analyzer (BIA, bioelectrical impedance analysis). Quantitative insulin-sensitivity check index, homeostasis model assessment for insulin resistance, and McAuley indices were calculated. Spinal mobility was assessed by the Bath Ankylosing Spondylitis Metrology Index (BASMI). Patients were also evaluated with the Bath Ankylosing Spondylitis Functional Index and the Bath Ankylosing Spondylitis Disease Activity Index. Age, sex distribution, smoking status, serum lipids, insulin concentrations, and insulin resistance indices were comparable between AS patients and controls (p > 0.05). However, acute phase reactants were significantly higher and leptin levels were significantly lower in the AS patients than in controls (p < 0.05). Fat percent assessed by both BIA and anthropometrical methods was lower in the male and female AS patients than in controls, and this reduced fat level reached statistical significance for men (p < 0.05). There were significant correlations between percent body fat, body mass index, leptin, age, and BASMI (p < 0.05; r = 0.6, 0.75, 0.35, −0.41, respectively). On the other hand, body fat percent, waist-to-hip ratio, C-reactive protein, and BASMI were significantly correlated with serum leptin levels (p < 0.05; r = 0.75, −0.42, −0.52, −0.47, respectively). Chronic inflammatory condition in AS may be responsible for the reduced body fat content and lower circulating leptin concentrations. Insulin levels and insulin resistance indices seem similar in patients and controls in the absence of classic vascular risk factors.


Arthritis Research & Therapy | 2012

Takayasu's arteritis is associated with HLA-B*52, but not with HLA-B*51, in Turkey

Ziver Sahin; Muge Bicakcigil; Kenan Aksu; Sevil Kamali; Servet Akar; Fatos Onen; Omer Karadag; Zeynep Ozbalkan; Aşkın Ateş; Huseyin T. E. Ozer; Vuslat Yilmaz; Emire Seyahi; Mehmet Akif Öztürk; Ayse Cefle; Veli Cobankara; A. Mesut Onat; Ercan Tunc; Nurşen Düzgün; Sibel Zehra Aydin; Neslihan Yilmaz; Izzet Fresko; Yasar Karaaslan; Sedat Kiraz; Nurullah Akkoc; Murat Inanc; Gokhan Keser; F. Aytül Uyar; Güher Saruhan-Direskeneli

IntroductionHLA-B*51 and HLA-B*52 are two close human leukocyte antigen (HLA) allele groups with minor amino acid differences. However, they are associated with two different vasculitides (HLA-B*51 in Behçets disease and HLA-B*52 in Takayasus arteritis (TAK)) and with major clinical and immunological differences. In this study, we aimed to screen a large cohort of TAK patients from Turkey for the presence of HLA-B*51 and HLA-B*52 as susceptibility and severity factors.MethodsTAK patients (n = 330) followed at a total of 15 centers were included in the study. The mean age of the patients was 37.8 years, and 86% were women. DNA samples from the patients and healthy controls (HC; n = 210) were isolated, and the presence of HLA-B*51 or HLA-B*52 was screened for by using PCR with sequence-specific primers.ResultsWe found a significant association of HLA-B*52 with TAK (20.9% vs HC = 6.7%, P = 0.000, OR = 3.7, 95% CI = 2.02 to 6.77). The distribution of HLA-B*51 did not differ between TAK patients and HCs (22.7% vs 24.8%, OR = 0.9, 95% CI = 0.60 to 1.34). The presence of HLA-B*52 decreased in late-onset patients (> 40 years of age; 12.0%, P = 0.024, OR = 0.43, 95% CI = 0.20 to 0.91). Patients with angiographic type I disease with limited aortic involvement also had a lower presence of HLA-B*52 compared to those with all other disease subtypes (13.1% vs 26%, P = 0.005, OR = 0.43, 95% CI = 0.23 to 0.78).ConclusionsIn this study, the previously reported association of TAK with HLA-B*52 in other populations was confirmed in patients from Turkey. The functional relevance of HLA-B*52 in TAK pathogenesis needs to be explored further.


International Journal of Clinical Practice | 2009

Prevalence of primary Sjogren's syndrome in Turkey: a population-based epidemiological study.

Merih Birlik; Servet Akar; Oguz Gurler; Ismail Sari; B. Birlik; Sulen Sarioglu; Mehmet Ali Öktem; Funda Saglam; Gercek Can; H. Kayahan; Nurullah Akkoc; Fatos Onen

Objectives:  The aim of this study was to determine the prevalence of primary Sjogren’s syndrome (pSS) in a general Turkish population according to the latest proposed American–European Consensus Group (AECG) criteria and European‐1 (EU‐1) criteria.

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Servet Akar

Dokuz Eylül University

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Ismail Sari

Dokuz Eylül University

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Merih Birlik

Dokuz Eylül University

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Fatos Onen

Dokuz Eylül University

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F. Onen

Dokuz Eylül University

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P. Cetin

Dokuz Eylül University

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Dilek Solmaz

Dokuz Eylül University

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Gercek Can

Dokuz Eylül University

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