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Dive into the research topics where Gökhan Kabaçam is active.

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Featured researches published by Gökhan Kabaçam.


Radiology | 2013

Hepatic Steatosis: Quantification by Proton Density Fat Fraction with MR Imaging versus Liver Biopsy

Ilkay S. Idilman; Hatice Aniktar; Ramazan Idilman; Gökhan Kabaçam; Berna Savas; Atilla Halil Elhan; Azim Celik; Kadir Bahar; Musturay Karcaaltincaba

PURPOSE To determine utility of proton density fat fraction (PDFF) measurements for quantifying the liver fat content in patients with nonalcoholic fatty liver disease (NAFLD), and compare these results with liver biopsy findings. MATERIALS AND METHODS This retrospective study was approved by the institutional review board with waivers of informed consent. Between June 2010 and April 2011, 86 patients received a diagnosis of NAFLD. Ten patients did not accept liver biopsy and six patients had contraindications for magnetic resonance (MR) imaging. Seventy patients were included in this study. Seventy patients with NAFLD (40 men, 30 women; mean age, 44.7 years; range, 16-69 years) underwent T1-independent volumetric multiecho gradient-echo imaging with T2* correction and spectral fat modeling. Median time interval between MR imaging and liver biopsy was 14.5 days (range, 0-259 days). MR examinations were performed with a 1.5-T MR imaging system. Complex-based PDFF measurements were performed by placing regions of interest in Couinaud system segments V-VI and all liver segments from I to VIII. All liver biopsy specimens were retrieved from archives and evaluated by one pathologist for hepatic steatosis according to criteria from a previous study. Pearson correlation coefficient, receiver operating characteristics, and linear regression analyses were used for statistical analyses. RESULTS Mean PDFF calculated with MR imaging was 18.1% ± 9.5 (standard deviation). Close correlation for quantification of hepatic steatosis was observed between PDFF and liver biopsy (r = 0.82). PDFF was effective in discriminating moderate or severe hepatic steatosis from mild or no hepatic steatosis, with area under the curve of 0.95. The correlation between biopsy and PDFF-determined steatosis was less pronounced when fibrosis was present (r = 0.60) than when fibrosis was absent (r = 0.86; P = .02). CONCLUSION PDFF measurement by MR imaging provided a noninvasive, accurate estimation of the presence and grading of hepatic steatosis in patients with NAFLD. Hepatic fibrosis reduced the correlation between biopsy results and PDFF.


European Journal of Internal Medicine | 2010

Serum vitamin B12 and folate status in patients with inflammatory bowel diseases

Mustafa Yakut; Yusuf Üstün; Gökhan Kabaçam; Irfan Soykan

BACKGROUND The aims of this study were to investigate the prevalence of serum vitamin B(12) and folate abnormalities in patients with inflammatory bowel diseases (IBD) and to identify risk factors associated with B12 and folate abnormalities in this entity. METHODS 138 patients with IBD (45 Crohns disease and 93 ulcerative colitis) and 53 healthy subjects were enrolled into the study. Fasting serum B12 and folic acid levels were measured and clinical data regarding inflammatory bowel diseases were gathered. RESULTS While the mean serum B(12) concentration in CD patients was 281+/-166pg/ml, the mean serum vitamin B12 concentration in UC patients was 348+/-218pg/ml (p=0.224). The number of patients with vitamin B12 deficiency in the CD group was greater than the number of patients with UC [n=10 (22%) vs. n=4 (7.5%), p=0.014]. The number of patients (n=10, 22%) with B12 deficiency in the CD group was also greater than controls (n=4, 7.5%) (p=0.039). With regard to folate levels, the median serum folate level was 7.7+/-5.3ng/ml in CD patients, 8.6+/-8.3ng/ml in UC patients and 9.9+/-3.3ng/ml in the control group (p=n.s.). Patients with a prior ileocolonic resection had an abnormal B12 concentration compared to patients without surgery (p=0.008). In CD patients, ileal involvement was the only independent risk factor for having a low folate level. CONCLUSION Serum vitamin B12 and folate deficiencies are common in patients with CD compared to UC patients and controls. In CD patients, prior small intestinal surgery is an independent risk factor for having a low serum vitamin B12 level.


Hepatology | 2014

Late HDV RNA relapse after peginterferon alpha-based therapy of chronic hepatitis delta

B. Heidrich; Cihan Yurdaydin; Gökhan Kabaçam; Boris A. Ratsch; Kalliopi Zachou; B. Bremer; George N. Dalekos; A. Erhardt; Fehmi Tabak; Kendal Yalçin; Selim Gurel; Stefan Zeuzem; Markus Cornberg; C.-Thomas Bock; Michael P. Manns; Heiner Wedemeyer

Interferon alpha is the only treatment option for hepatitis delta virus (HDV). Trials investigating the efficacy of pegylated interferon alpha (PEG‐IFNa) showed HDV RNA negativity rates of 25‐30% 24 weeks after therapy. However, the clinical and virological long‐term outcome of HDV‐infected patients treated with PEG‐IFNa is unknown. We performed a retrospective‐prospective follow‐up of 77 patients treated for 48 weeks with either PEG‐alfa‐2a and adefovir (ADV) or either drug alone in the Hep‐Net‐International‐Delta‐Hepatitis‐Intervention‐Study 1 (HIDIT‐1) trial. Long‐term follow‐up data were available for 58 out of 77 patients (75%) with a median time of follow‐up of 4.5 (0.5‐5.5) years and a median 3 visits per patient. Patients treated with ADV alone received retreatment with PEG‐IFNa (48% versus 19%; P = 0.02) more often. Hepatitis B virus surface antigen (HBsAg) became negative in six PEG‐IFNa‐treated patients until the end of long‐term follow‐up (10%). Sixteen patients tested HDV RNA‐negative 6 months after PEG‐IFNa treatment who were entered in the long‐term follow‐up study. Out of these, nine individuals tested HDV RNA‐positive at least once during further long‐term follow‐up, with seven patients being HDV RNA‐positive at the most recent visit. Clinical endpoints (liver‐related death, liver transplantation, hepatic decompensation, hepatocellular carcinoma) were observed in three PEG‐IFNa‐treated (8%) and three ADV‐treated (14%) patients during posttreatment long‐term follow‐up with an overall annual event rate of 2.5% (4.9% in cirrhosis). Sequencing confirmed the reappearance of pretreatment virus strains in all cases. Conclusion: Late HDV RNA relapses may occur after PEG‐IFNa therapy of hepatitis delta and thus the term sustained virological response should be avoided in HDV infection. The annual posttreatment rate of clinical events in hepatitis delta patients eligible for PEG‐IFNa therapy is about 2.5% and 4.9% in patients with cirrhosis. (Hepatology 2014;60:87‐97)


Clinical Infectious Diseases | 2012

Entecavir Treatment of Chronic Hepatitis D

Gökhan Kabaçam; F. Oğuz Önder; Mustafa Yakut; Gülseren Seven; Senem Karatayli; Ersin Karatayli; Berna Savas; Ramazan Idilman; A. Mithat Bozdayi; Cihan Yurdaydin

BACKGROUND Hepatitis D virus (HDV) requires hepatitis B surface antigen (HBsAg) to propagate infection and cause disease. Entecavir is a nucleoside analog with potent antiviral efficacy, and in the woodchuck animal model it also decreased hepatitis B virus (HBV) cccDNA and woodchuck surface antigen. The aim of this study was to investigate the efficacy of entecavir in chronic hepatitis D (CHD). METHODS This single-center study was conducted in patients with compensated liver disease. All patients had to have detectable hepatitis HDV RNA and elevated levels of alanine aminotransferase (ALT). Entecavir was given at a dosage of 1 mg/d for 1 year. The primary end point was achievement of undetectable HDV RNA at the end of treatment. RESULTS Thirteen consecutive patients were assessed. All patients had detectable HDV RNA, and 8 had detectable HBV DNA at baseline. At the end of treatment, HBV DNA became undetectable in all patients (P = .001). No significant decline in HDV RNA, ALT, or quantitative HBsAg levels was observed. The primary end point of undetectable HDV RNA at the end of treatment was achieved in 3 patients who had significantly lower baseline HDV RNA levels than nonresponders (2.99 log(10) copies/mL ± .70 vs 4.68 ± .97; P = .0185). In all 3 patients, ALT levels were also normal at the end of treatment. CONCLUSIONS One year of entecavir treatment is ineffective in CHD. Any generalized beneficial effect of nucleoside/nucleotide analog treatment may necessitate prolonged treatment. Patients with CHD with HBV dominance, which is likely to occur in the later phases of CHD, may be a reasonable patient cohort in which to target nucleoside/nucleotide analog therapy.


Liver International | 2012

HBeAg-positive hepatitis delta: virological patterns and clinical long-term outcome.

B. Heidrich; Beatriz Calle Serrano; Ramazan Idilman; Gökhan Kabaçam; B. Bremer; R. Raupach; Fatih Oguz Onder; Katja Deterding; Behrend J. Zacher; Andrzej Taranta; Hakan Bozkaya; Kalliopi Zachou; Hans L. Tillmann; A.M. Bozdayi; Michael P. Manns; Cihan Yurdaydin; Heiner Wedemeyer

The presence of the hepatitis B virus (HBV)‐eAg in patients with hepatitis B is associated with higher HBV replication and with an increased risk to develop liver‐related clinical endpoints defined as liver related death, liver transplantation, development of hepatocellular carcinoma and hepatic decompensation. The aim of this study was to investigate the role of HBeAg in patients co‐infected with the hepatitis D virus (HDV).


Antiviral Therapy | 2014

Efficacy of tenofovir in adefovir-experienced patients compared with treatment-naive patients with chronic hepatitis B.

Onur Keskin; Ormeci Ac; Baran B; Gökhan Kabaçam; Tüzün A; Ersin Karatayli; Filiz Akyuz; Senem Karatayli; A.M. Bozdayi; Onel D; Badur S; Ramazan Idilman; Sabahattin Kaymakoglu; Cihan Yurdaydin

BACKGROUND Tenofovir (TDF) has similar antiviral efficacy in both treatment-naive and lamivudine-resistant chronic hepatitis B (CHB) patients. Data on TDF use in patients with adefovir (ADV) resistance is inconsistent. The aim of our study was to assess antiviral efficacy of TDF against nucleoside analogue-naive (NN) and ADV-resistant (ADV-R) CHB and suboptimal responders to ADV (ADV-S). METHODS A database of 135 CHB patients treated with TDF was analysed. A total of 37 patients with incomplete data were excluded and analysis was performed in 98 (44 NN, 30 ADV-R and 24 ADV-S). Patients with primary ADV-R mutations had either A181T/V or N236T mutations or both. HBV DNA was measured at 3-month intervals until month 24. Primary outcome measures were comparison of the decline of HBV DNA between the three treatment groups. RESULTS NN patients had higher baseline HBV DNA compared with ADV-R and ADV-S patients (6.08 log10 IU/ml versus 5.53 and 4.88, respectively; P=0.002). By exponential regression analysis, HBV DNA decline kinetics differed between the three groups. HBV DNA decline was faster in NN patients compared to ADV-R and ADV-S CHB patients (P=0.002 and P=0.004, respectively). Undetectable HBV DNA was achieved in 77.2%, 60% and 75% of NN, ADV-R and ADV-S CHB patients, respectively, at month 12 (P= not significant). CONCLUSIONS HBV DNA decline is slower in ADV-experienced patients compared with treatment-naive patients. The clinical significance of this slow response may be important in patients with critical liver reserve and high viral load. Optimal combination treatment (TDF+ entecavir) could be considered in these patients.


Southern Medical Journal | 2011

Clinical Characteristics and Evaluation of Patients with Large Hiatal Hernia and Cameron Lesions

Mustafa Yakut; Gökhan Kabaçam; Ayşegül Öztürk; Irfan Soykan

Objectives: Cameron lesions are located at the neck of large hiatal hernias, and are associated with anemia or overt gastrointestinal (GI) bleeding. The aim of this study was to investigate the clinical and endoscopic properties of patients with Cameron lesions. Methods: Eighteen patients were diagnosed as having large hiatal hernia and Cameron lesions. Patients with Cameron lesions (n = 18) were compared to patients with large hiatal hernias without Cameron lesions (n = 26), by means of presenting symptoms and endoscopic findings. Results: The mean age of patients with Cameron lesions was significantly higher than patients without Cameron lesions (71.1 ± 11.63 vs 56.7 ± 17.4 years, P = 0.005). The ratio of female patients with Cameron lesions was higher compared to patients with large hiatal hernia without Cameron lesions (14/18 [77.7%] vs 12/26 [46.1%], P = 0.00). While 12 of 18 patients with Cameron lesions had overt GI bleeding, none of the patients with large hiatal hernia without Cameron lesions had signs of GI bleeding. Fifteen of 18 patients had ulcers in the hernia sac and the others had linear erosions. There was no significant difference between patients with and without Cameron lesions by means of hemoglobin levels (11.1 ± 2.20 vs 12.2 ± 2.5 g/dL, P = 0.157). Conclusion: Most patients with large hiatal hernia and Cameron lesions presented with overt GI bleeding. Patients with Cameron lesions tend to be older females. In patients with anemia and GI bleeding, large hiatal hernia and Cameron erosions should also be considered.


Journal of Hepatology | 2013

46 LONG-TERM FOLLOW-UP AFTER PEG-IFNa2a-BASED THERAPY OF CHRONIC HEPATITIS DELTA

B. Heidrich; Cihan Yurdaydin; Gökhan Kabaçam; Kalliopi Zachou; B. Bremer; Georgios N. Dalekos; A. Erhardt; Yilmaz Cakaloglu; Kendal Yalçin; Selim Gurel; Stefan Zeuzem; T. Bock; Ramazan Idilman; Michael P. Manns; Heiner Wedemeyer

45 IMMUNE EVASION OF HEPATITIS DELTA FROM CD8+ T CELL IMMUNE RESPONSE H. Karimzadeh, A. Kosinska, B. Budeus, M. Fiedler, M. Homs, A. Olivero, M. Buti, H. Keyvani, F. Rodriguez Frias, S.M. Alavian, D. Hoffmann, A. Smedile, M. Rizzetto, H. Wedemeyer, J. Timm, M. Roggendorf. Institute of Virology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany; Department of Bioinformatics, University of Duisburg-Essen, Essen, Germany; Department of Biochemistry, Hospital Universitari Vall d’Hebron (HUVH), Vall d’Hebron Research Institute (VHIR) University Autonoma de Barcelona (UAB), Barcelona, Spain; Department of Internal Medicine, University of Turin, Turin, Italy; School of Medicine, Tehran University of Medical Sciences, Tehran, Iran, Department of Gastroenterology, Hepatology and Endocrinology, Medical School of Hannover, Hannover, Germany E-mail: [email protected]


Antiviral Therapy | 2012

Clonal analysis of the quasispecies of antiviral-resistant HBV genomes in patients with entecavir resistance during rescue treatment and successful treatment of entecavir resistance with tenofovir.

Ersin Karatayli; Ramazan Idilman; Senem Karatayli; Cevik E; Mustafa Yakut; Gülseren Seven; Gökhan Kabaçam; A.M. Bozdayi; Cihan Yurdaydin

BACKGROUND Clonal analysis of quasispecies of resistant HBV genomes in patients with entecavir (ETV) resistance receiving lamivudine (3TC) plus adefovir (ADV) rescue therapy has never been performed. METHODS A sample of 10 patients with ETV resistance who were switched to 3TC+ADV treatment were analysed for changes in viral quasispecies. Serum samples at baseline, and at months 3 and 6 of 3TC+ADV treatment could be clonally analysed in 7 of 10 patients; 3-82 clones per sample (total 1,068 clones, mean 63) were sequenced. RESULTS 3TC+ADV therapy led to a modest decline in HBV DNA. Almost all clones had L180M and M204V 3TC resistance mutations before and during combination therapy. All clones had ≥1 of the S202G, T184F, T184A, T184L, T184I and M250V ETV resistance mutations. The percentages of detected clones bearing 3TC (rtL180M and rtM204V) and ETV mutations did not change with rescue 3TC+ADV therapy. In 7 of 8 patients with detectable HBV DNA (median 5.17 log(10) copies/ml) after a median 24 months of ADV therapy, HBV DNA became undetectable with 3TC plus tenofovir after 6 months of treatment. CONCLUSIONS In patients with ETV resistance tenofovir is effective. Clonal analysis data indicate no selection of specific HBV mutants during rescue 3TC+ADV.


Liver International | 2014

Role of immunohistochemistry for hepatitis D and hepatitis B virus in hepatitis delta.

Gökhan Kabaçam; Heiner Wedemeyer; Berna Savas; Onur Keskin; George N. Dalekos; Fehmi Tabak; Ramazan Idilman; A. Erhardt; Kendal Yalçin; Mithat Bozdayi; Hakan Bozkaya; Michael P. Manns; Hans Peter Dienes; Cihan Yurdaydin

Immunohistochemical assessment of liver tissue in chronic delta hepatitis (CDH) is underinvestigated. Aim of the study was (i) to assess variables associated with hepatitis D antigen (HDAg), hepatitis B surface antigen (HBsAg) and hepatitis B core antigen (HBcAg) staining in the liver.

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