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Featured researches published by Tarkan Karakan.


Helicobacter | 2007

Efficacy and Safety of Saccharomyces boulardii in the 14-day Triple Anti-Helicobacter pylori Therapy: A Prospective Randomized Placebo-Controlled Double-Blind Study

Mehmet Cindoruk; Gülbanu Erkan; Tarkan Karakan; Ayse Dursun; Selahattin Unal

Background:  Recent studies indicate a potential role of Saccharomyces boulardii in the prevention of Helicobacter pylori treatment‐related side‐effects and also in improvement of eradication rate. Our aim is to investigate the efficacy and safety of S. boulardii in the prevention of side‐effects related to H. pylori eradication. The secondary aim of the study was to define the effect of S. boulardii on the eradication success of anti‐H. pylori therapy.


Gastrointestinal Endoscopy | 2009

EUS versus endoscopic retrograde cholangiography for patients with intermediate probability of bile duct stones: a prospective randomized trial

Tarkan Karakan; Mehmet Cindoruk; Hakan Alagozlu; Meltem Ergun; Sukru Dumlu; Selahattin Unal

BACKGROUND Factors affecting diagnostic accuracy and comparison of patients in the follow-up period for negative outcomes are not thoroughly investigated in a randomized trial. OBJECTIVE Our purpose was to compare diagnostic accuracy, complications, and number of interventions. DESIGN Prospective, unicentric, single-blind, randomized study. SETTING Single tertiary referral university hospital. PATIENTS One hundred twenty patients with intermediate risk for common bile duct (CBD) stones were randomized to either an EUS-first, endoscopic retrograde cholangiography (ERC)-second (n = 60) versus an ERC-only (n = 60) procedure. INTERVENTIONS EUS, ERC, sphincterotomy, and balloon sweeping of CBD when needed. MAIN OUTCOME MEASUREMENTS Sensitivity of EUS versus ERC, factors affecting diagnostic capability, complications, total number of endoscopic procedures. RESULTS The sensitivity and specificity of ERC were 75% (95% CI, 42%-93%) and 100% (95% CI, 95%-100%), respectively. The sensitivity and specificity of EUS were 91% (95% CI, 59%-99%) and 100% (95% CI, 95%-100%), respectively. EUS is more sensitive than ERC in detecting stones smaller than 4 mm (90% vs 23%, P < .01). Although not significant, there was a trend for an increased number of endoscopic procedures in the ERC group compared with the EUS group (98 vs 83). The post-ERC pancreatitis rate was 6 in 120 (5%) in all study patients, and the post-ERC pancreatitis rate in patients with an undilated CBD was 5 of 53 (9.43%). The independent factors for post-ERC pancreatitis are undilated CBD (risk ratio [RR] 6.320; 95% CI, 1.703-11.524, P = .009), allocation into the ERC group (RR 2.107; 95% CI, 1.330-3.339, P = .02), female sex (RR 1.803; 95% CI, 1.155-2.813, P = .03), and age less than 40 years (RR 1.888; 95% CI, 1.245-2.863, P = .01). Kaplan-Meier analysis revealed higher rate of negative outcome in the ERC group than in the EUS group (P = .049, log-rank test). CONCLUSION The EUS-first approach is not associated with further risk for subsequent endoscopic procedures. Patients with an undilated CBD should be investigated by the EUS-first approach to prevent post-ERC pancreatitis.


Renal Failure | 2006

Prevalence of occult hepatitis B and hepatitis C virus infections in Turkish hemodialysis patients

Fahri Yakaryilmaz; Oguz Alp Gurbuz; Sefa Güliter; Ali Mert; Yıldıran Songür; Tarkan Karakan; Hatice Keles

Background and Objective. Hepatitis B virus (HBV) and hepatitis C virus (HCV) infections are important causes of morbidity and mortality in maintenance hemodialysis patients. Although their exact prevalence is not known, HBV and HCV viral infections and occult viral hepatitis are frequent in these patients. This study aimed to determine the prevalence of occult HBV and HCV infections in maintenance hemodialysis patients. Materials and Methods. One hundred and eighty-eight end-stage renal disease patients on maintenance hemodialysis (100 male, mean age 49±29 [16–80] years, and mean duration of hemodialysis 98±66 [12–228] months) were enrolled in this study. Serological markers for HBV and HCV were determined with immunoenzymatic assay (ELISA) by using commercial diagnostic kits (Access and BioRad, Beckman-Coulter). HCV-RNA (Cobas Amplicor HCV kit) and HBV-DNA (Artus GmbH HBV kit) were determined quantitatively by polymerase chain reaction. Results. Among the patients screened, 25 (13.3%) had HBV infection alone and 38 (20.2%) had HCV infection alone, while seven (3.7%) had dual infection of both viruses. Serological markers for occult hepatitis B and occult hepatitis C were positive in five (2.7%) and nine (4.8%) of the patients, respectively. Isolated anti-HBc was positive in 12 (6.4%) of all patients, three (7.9%) of the patients with anti-HCV and two (40%) of the patients with occult hepatitis B. Isolated anti-HBc positivity was more frequent in patients with occult hepatitis B than in those without (40% [2/5] vs. 5.5% [10/183], p=0.002). None of the patients with HCV had occult hepatitis B. Conclusions. Both occult and non-occult forms of HCV infection are more prevalent than HBV infection in hemodialysis patients. Especially the patients with isolated anti-HBc positivity should be tested for probable occult hepatitis B infection.


Digestive Diseases and Sciences | 2006

Heparin and Insulin in the Treatment of Hypertriglyceridemia-Induced Severe Acute Pancreatitis

Hakan Alagozlu; Mehmet Cindoruk; Tarkan Karakan; Selahattin Unal

Heparin and insulin stimulate lipoprotein lipase activity. Therefore, they reduce serum triglyceride levels. However, heparin and insulins efficacy in treatment of hypertriglyceridemia-induced acute pancreatitis is not well established. We report a patient in whom heparin and insulin were used successfully.


Bone Marrow Transplantation | 2008

The role of liver biopsy in the workup of liver dysfunction late after SCT: is the role of iron overload underestimated?

Gülsan Türköz Sucak; Zeynep Arzu Yegin; Zübeyde Nur Özkurt; Sahika Zeynep Aki; Tarkan Karakan; Gülen Akyol

Abnormalities in liver function tests are common in hematopoietic SCT (HSCT) recipients. We retrospectively investigated the role of liver biopsy in determining the cause of elevated liver enzymes and its impact on the management of patients in the post-HSCT setting. A total of 24 consecutive liver biopsies were obtained from 20 patients from September 2003 to December 2007. A definite histopathologic diagnosis was obtained in 91.7% of the biopsies. Iron overload (IO) was found in 75% and GVHD in 54.2% of the patients. The initial clinical diagnosis of GVHD was confirmed in 56.5% and refuted in 43.5% of the allogeneic HSCT recipients. The median number of post transplant transfusions, percent transferrin saturation and ferritin levels were found to be higher in patients who had histologically proven hepatic IO (p1=0.007, p2=0.003 and p3=0.009, respectively). Regression analysis showed a significant correlation between serum ferritin levels and histological grade of iron in the hepatocytes. Our data suggest that hepatic IO is a frequent finding in the post-HSCT setting, which contributes to hepatic dysfunction and it should be considered in the differential diagnosis, particularly in patients with high serum ferritin levels.


Journal of Clinical Gastroenterology | 2007

Hepatic steatosis has no impact on the outcome of treatment in patients with chronic hepatitis B infection.

Mehmet Cindoruk; Tarkan Karakan; Selahattin Unal

Background Hepatic steatosis, as a predictive factor in treatment outcome, was not investigated in chronic hepatitis B (CHB). The aim of this retrospective analysis is to determine possible relationships between hepatic steatosis and treatment response in patients with CHB. Methods One hundred forty patients with CHB [42 hepatitis B e antigen (HBeAg)-positive, 98 HBeAg-negative] were analyzed. Seventy-eight patients (55.7%) received pegylated interferon α 2a 180 μg/wk subcutaneously and 62 patients (44.3%) received pegylated interferon α 2a 180 μg/wk plus lamivudine 100 mg/d combination therapy. Results The presence of steatosis was associated with increased body mass index and hyperlipidemia. The sustained virologic response (SVR) rates in HBeAg-negative patients were 36.2% and 31.5% in patients with and without steatosis, respectively (P>0.05). The SVR rates in HBeAg-positive patients were 39.6% and 33.3% in patients with and without steatosis, respectively (P>0.05). The prevalence of hepatic steatosis did not significantly affect the outcome of treatments in both groups. In pegylated interferon monotherapy group (group 1), SVR was 18/78 (23%) and in the pegylated interferon plus lamivudine combination group (group 2) SVR was 16/62 (26%), (P>0.05, NS). The independent factors affecting the treatment outcome were higher baseline alanine aminotransferase level and lower baseline viral load. Conclusions The prevalence of steatosis is a common finding in CHB infection; however, it is not associated with viral load and treatment outcome.


Medical Oncology | 2010

Imatinib mesylate-induced acute liver failure in a patient with gastrointestinal stromal tumors

Onder Tonyali; Ugur Coskun; Ramazan Yildiz; Tarkan Karakan; Umut Demirci; Nalan Akyürek; Mustafa Benekli; Suleyman Buyukberber

Imatinib mesylate is a drug that has been approved for treatment of chronic myeloid leukemia, Philadelphia-positive acute lymphoblastic leukemia, and advanced gastrointestinal stromal tumors. Several cases of hepatotoxicity, including fatal liver failure, have been reported with the long-term use of imatinib mesylate. Generally hepatotoxicity resolves after discontinuation of imatinib. Despite discontinuation of imatinib, hepatotoxicity can be progressive. Steroid may be useful in these patients and should be started early. We report a 53-year-old woman with advanced gastrointestinal stromal tumors who developed hepatotoxicity while receiving imatinib and subsequently acute liver failure. Ten weeks after commencing imatinib treatment, hepatotoxicity was determined. Imatinib was immediately ceased. Subsequently, a week later hepatic encephalopathy, jaundice, and coagulopathy occurred. Prednisolone was commenced. Liver biopsy was performed five weeks after the determining of hepatotoxicity. Biopsy showed sinusoidal congestion, necrosis of hepatocytes, inflammation, and hepatocyte drop out around the hepatic venule consistent with drug toxicity. Her liver function tests normalized with a nine-week prednisolone treatment. The patient was discharged. Her liver enzymes remained in normal range following visits. In cases of imatinib-induced acute hepatitis, the administration of prednisolone may be useful in the resolution of the acute episode and allow the reintroduction of a drug without risking recurrence of hepatitis.


World Journal of Gastroenterology | 2012

Current endoscopic approach to indeterminate biliary strictures

David W. Victor; Stuart Sherman; Tarkan Karakan; Mouen A. Khashab

Biliary strictures are considered indeterminate when basic work-up, including transabdominal imaging and endoscopic retrograde cholangiopancreatography with routine cytologic brushing, are non-diagnostic. Indeterminate biliary strictures can easily be mischaracterized which may dramatically affect patients outcome. Early and accurate diagnosis of malignancy impacts not only a patients candidacy for surgery, but also potential timely targeted chemotherapies. A significant portion of patients with indeterminate biliary strictures have benign disease and accurate diagnosis is, thus, paramount to avoid unnecessary surgery. Current sampling strategies have suboptimal accuracy for the diagnosis of malignancy. Emerging data on other diagnostic modalities, such as ancillary cytology techniques, single operator cholangioscopy, and endoscopic ultrasonography-guided fine needle aspiration, revealed promising results with much improved sensitivity.


BMC Gastroenterology | 2007

Peroxisome proliferators-activated alpha agonist treatment ameliorates hepatic damage in rats with obstructive jaundice: an experimental study

Mehmet Cindoruk; Mustafa Kerem; Tarkan Karakan; Bülent Salman; Okan Akin; Murat Alper; Ozlem Erdem; Selahattin Unal

BackgroundPeroxisome proliferators-activated receptor alpha (PPARα) activation modulates cholesterol metabolism and suppresses bile acid synthesis. This study aims to evaluate the effect of short-term administration of fenofibrate, a PPARα agonist, on proinflammatory cytokines, apoptosis, and hepatocellular damage in cholestasis.MethodsForty male Wistar rats were randomly divided into four groups: I = sham operated, II = bile duct ligation (BDL), III = BDL + vehicle (gum Arabic), IV = BDL + fenofibrate (100 mg/kg/day). All rats were sacrificed on 7th day after obtaining blood samples and liver tissue. Total bilirubin, aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP), gamma-glutamyl transferase, (GGT), tumor necrosis factor alpha (TNF-α), interleukin 1 beta (IL-1 β), and total bile acid (TBA) in serum, and liver damage scores; portal inflammation, necrosis, bile duct number, in liver tissue were evaluated. Apoptosis in liver was also assessed by immunohistochemical staining.ResultsFenofibrate administration significantly reduced serum total bilirubin, AST, ALT, ALP, and GGT, TNF-α, IL-1 β levels, and TBA (P < 0.01). Hepatic portal inflammation, hepatic necrosis, number of the bile ducts and apoptosis in rats with BDL were more prominent than the sham-operated animals (P < 0.01). PPARα induction improved all histopathologic parameters (P < 0.01), except for the number of the bile duct, which was markedly increased by fenofibrate therapy (P < 0.01).ConclusionShort-term administration of fenofibrate to the BDL rats exerts beneficial effects on hepatocellular damage and apoptosis.


European Journal of Gastroenterology & Hepatology | 2008

Identification of Helicobacter species by 16S rDNA PCR and sequence analysis in human liver samples from patients with various etiologies of benign liver diseases

Mehmet Cindoruk; Meltem Yalinay Cirak; Selahattin Unal; Tarkan Karakan; Gülbanu Erkan; Doruk Engin; Sukru Dumlu; Sevgi Turet

Background/Aims Several reports indicated an increased prevalence of the Helicobacter species in hepatocellular cancer tissue and in liver samples infected with hepatitis viruses. The frequency of Helicobacter spp. in benign liver diseases was, however, not thoroughly investigated. Methods Seventy-five consecutive patients with suspected liver disease were enrolled. The indications were hepatitis B virus (n=30), C virus (n=8), B and C dual infection (n=1), nonalcoholic steatohepatitis (n=27), autoimmune hepatitis (n=3), primary biliary cirrhosis (n=1) and idiopathic elevation of liver enzymes (n=5). PCR detection of 16S recombinant RNA gene of Helicobacter spp. was performed on liver samples. PCR products of positive samples were further identified by DNA sequencing. The patients also had upper gastrointestinal endoscopy and gastric biopsy for the detection of H. pylori using histopathology and PCR. Results Helicobacter spp. DNA was detected in two out of 75 liver biopsy samples (2.6%), which were typed as H. pylori by DNA sequencing. One of these patients had chronic hepatitis C infection (man, 51 years old) and the other had nonalcoholic steatohepatitis (woman, 44 years old). Fifty-two out of 75 of the patients (69.3%) had H. pylori infection in their stomachs. Conclusion We have found that H. pylori infection is much less prevalent in benign liver diseases. The presence of H. pylori in nonalcoholic steatohepatitis (NASH) patients is a novel finding and this finding should be confirmed in a larger series.

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