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Dive into the research topics where Zeki Karasu is active.

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Featured researches published by Zeki Karasu.


Alimentary Pharmacology & Therapeutics | 2008

Safety, tolerability, and efficacy of pegylated-interferon alfa-2a plus ribavirin in HCV-related decompensated cirrhotics.

Fatih Tekin; Fulya Gunsar; Zeki Karasu; U.S. Akarca; Galip Ersoz

Background  Pretransplantation clearance of hepatitis C virus (HCV)‐RNA reduces the risk of HCV recurrence after transplantation. Furthermore, a sustained virological response could reduce disease progression and slow clinical deterioration in nontransplanted patients.


Clinical Transplantation | 2002

Mycobacterium tuberculosis infection and laboratory diagnosis in solid-organ transplant recipients

Cengiz Cavusoglu; Candan Cicek‐Saydam; Zeki Karasu; Yeser Karaca; Mehmet Ozkahya; Huseyin Toz; Yaman Tokat; Altinay Bilgic

Tuberculosis (TB) is an unusual infection in transplant recipients. We evaluated (i) the frequency of TB, (ii) the duration to develop the TB infection, and (iii) clinical consequences, in 380 solid‐organ recipients from January 1995 to December 2000. A total of 10 (2.63%) patients (eight renal, two liver transplant recipients) were found to have post‐transplantation TB. The frequency of TB in this patient population is 8.5‐fold higher than the prevalance in the general Turkish population. Tuberculosis developed within 2–33 months after transplantation, with a median of 15 months. In all of these 10 patients, Mycobacterium tuberculosis (MTB) was isolated from the culture. All the patients continued to have low dose immunosuppressive treatment, and also quadriple antituberculosis treatment [isoniazid (INH), rifampin (RIF), pyrazinamide (PRZ) and ethambutol (ETB)] has been given. The two recipients had died of disseminated form of TB. Relapse was detected in one patient 6 months after the completion of the treatment. As post‐transplant TB infection develops mostly within the first year after transplantation, clinicians should be more careful for early and fast diagnosis and treatment should be started immediately.


Digestive Diseases and Sciences | 2007

Liver Fibrosis Is Associated with Decreased Peripheral Platelet Count in Patients with Chronic Hepatitis B and C

Zeki Karasu; Fatih Tekin; Galip Ersoz; Fulya Gunsar; Yücel Batur; Tankut Ilter; U.S. Akarca

Thrombocytopenia is a common complication of chronic liver diseases, but its pathogenesis is not clear. Although generally attributed to hypersplenism, other factors should also be considered. We investigated the relationship between the peripheral platelet count and the degree of fibrosis in patients with chronic viral hepatitis. In an effort to avoid the effects of hypersplenism, we excluded patients with splenomegaly and/or bi- or pan-cytopenia. Seven hundred eighty-four patients (265 chronic viral hepatitis C and 519 chronic viral hepatitis B) were included in the study. Univariate analysis showed that the peripheral platelet count had a negative correlation with fibrosis score, necroinflammatory activity, and age in both groups. In multivariate analysis, the peripheral platelet count had a similar correlation with the fibrosis score and age, but not with necroinflammatory activity, in both groups. The peripheral platelet count decreased more significantly in females with chronic hepatitis C but not in the chronic hepatitis B group. In conclusion, a decrease in peripheral platelet count may be a sign of an increase in the degree of fibrosis during the course of chronic viral hepatitis B and C and factors other than hypersplenism may play a role in this decrease in the peripheral platelet count.


Journal of Gastroenterology and Hepatology | 2007

Adefovir dipivoxil therapy in liver transplant recipients for recurrence of hepatitis B virus infection despite lamivudine plus hepatitis B immunoglobulin prophylaxis

Murat Akyildiz; Zeki Karasu; Murat Zeytunlu; Unal Aydin; Tijen Özacar; Murat Kilic

Background:  Treatment of post‐transplantation recurrence of hepatitis B virus (HBV) infection despite prophylaxis with hepatitis B immunoglobulin (HBIG) and lamivudine combination therapy is not easy. Because HBV reinfection has a severe course and could result in graft failure in liver transplant recipients, prompt medication is essential. Herein is reported the authors’ experience with adefovir dipivoxil (AD) therapy in 11 liver transplant recipients who had HBV reinfection despite the administration of lamivudine and HBIG.


Liver Transplantation | 2010

Expression of matrix metalloproteinase‐9 in predicting prognosis of hepatocellular carcinoma after liver transplantation

Deniz Nart; Banu Yaman; Funda Yilmaz; Murat Zeytunlu; Zeki Karasu; Murat Kilic

Matrix metalloproteinases (MMPs) are known to play an important role in cell migration during cancer invasion by degrading extracellular matrix proteins. This study aimed to determine the role of MMP‐9 in hepatocellular carcinoma (HCC) carcinogenesis. Eighty‐nine cases who underwent liver transplantation for HCC in cirrhotic liver were selected for this study. The tumor characteristics such as nodule number, maximal diameter, portal vein invasion, and the preoperative alpha‐fetoprotein levels were reviewed. The intensity of immunostaining and the percentage of immunoreactive cells with MMP‐9 were evaluated. All patients were evaluated for HCC recurrence and/or death, and cause of death was noted. There was a lower survival and more recurrence risk among participants with 4 or more nodules exceeding 3 cm in diameter, with poorly differentiated tumor, and with large‐vessel involvement. Eleven patients developed recurrent HCC (12.4%). Twelve patients died as a result of HCC (13.5%). Among 89 HCCs, the incidences of a weak (+) and moderate (++) expression of MMP‐9 in carcinoma cells were 30.3% (23/89) and 43.8% (39/89), respectively. Increased expression and intensity of MMP‐9 were found to be inversely associated with poor tumor differentiation (P = 0.016, P = 0.009, respectively). A significant correlation between expression and intensity of MMP‐9 and large vascular invasion (P = 0.01, and P = 0.03) was also observed. As far as prognosis is concerned, increased immunoreactivity and intensity of MMP‐9 were found to exert an unfavorable impact on overall survival rates (P < 0.01, P = 0.01, respectively) and recurrences (P = 0.001, P = 0.02). Multivariate analyses revealed that MMP‐9 staining percentage (P = 0.007) and portal vein invasion (P = 0.002) were independent predictors of survival, whereas the only independent predictor of recurrences was portal vein invasion (P = 0.007). In this study, our results indicate a positive association between MMP‐9 expression and histopathologic parameters that indicate poor prognosis. We conclude that together, MMP‐9 staining percentage and portal vein invasion in HCC may aid to predict poor outcome. Nevertheless MMP‐9 staining percentage is expected to be a potential predictive marker on survival and needs to be studied more in detail. Liver Transpl 16:621‐630, 2010.


Transplantation | 2007

Live donor liver transplantation for acute liver failure.

Murat Kilic; Unal Aydin; Aysin Noyan; Cigdem Arikan; Sema Aydogdu; Murat Akyildiz; Zeki Karasu; Murat Zeytunlu; Mehmet Alper; Yücel Batur

Background. Acute liver failure (ALF) carries a high mortality unless urgent orthotopic liver transplantation (OLT) is performed on time. Live donors are utilized to treat this irreversible condition first in pediatric cases and then in adults. Herein, we aimed to report our experience with live donors for ALF in a country of a deceased donor organ donation rate is only 1.5 per million people. Methods. Among the 245 live donor liver transplantations (LDLT) performed from June 1999 to December 2005, 14 of them (6%) were performed for ALF in 8 pediatric and 6 adult cases. Right lobes were harvested for the adult cases whereas left lateral segments were harvested for pediatric cases, except one child transplanted with a right lobe graft. The etiology of the disease was; acute hepatitis B in four cases, hepatitis A in three cases, Wilson disease two cases, autoimmune hepatitis in two cases, and was unknown in three cases. Results. Three-year graft and patient survival is 79% for these series. Five of the six adult patients and six of the eight pediatric cases survived after transplantation. There was not any donor mortality or major morbidity. Conclusions. LDLT offers a safe and effective modality of treatment for ALF for both pediatric and adult patients to overcome the problem of organ shortage especially in countries where the chance of receiving an organ from a deceased donor is low.


Transplantation | 2004

Recipient-derived hepatocytes in sex-mismatched liver allografts after liver transplantation: Early versus late transplant biopsies

Ramazan Idilman; Esra Erden; Isinsu Kuzu; Sadik Ersoz; Zeki Karasu; Kaan Karayalcin; Gül Yüce; Yaman Tokat; Yasemin Sahin; Ajlan Tukun; Ulus Salih Akarca; Selim Karayalcin

Background. The presence of microchimerism in transplanted tissues is well defined; however, the timeframe of appearance and disappearance of engraftment in liver allograft is unknown. The aims of this study were to analyze for the presence of “recipient-derived cells” in sex-mismatched individuals after liver transplantation, comparing the frequency of “recipient-derived cell repopulation” in early versus late transplant biopsies and to evaluate the relationship between “recipient-derived cell repopulation” and the severity of graft injury. Methods. Paraffin-embedded liver biopsy samples of 18 recipients were reviewed. Sixteen of them were obtained from recipients with sex-mismatched donors. The remaining two were obtained from recipients with sex-matched donors and were used as controls. Immunohistochemistry and fluorescence in situ hybridization double-labeling method were performed on pretreated slides using anti-human hepatocyte antibody to identify hepatocytes, a mouse anti-human cytokeratin-7 to identify ductal epithelial cells, and using CEPX/Y DNA probes for visualizing X and Y chromosomes. The double-labeled slides were examined systematically using an image analyzer system. Results. The mean time from transplantation to biopsy was 8.1 months. Eleven of the 16 samples obtained from recipients with sex-mismatched grafts demonstrated “recipient-derived hepatocyte repopulation,” comprising a mean of 2.1% of the hepatocytes. In the control biopsies, none of the cells demonstrated different nuclear signals from the donor’s sex origin. The presence and proportion of “recipient-derived hepatocyte repopulation” rate were significantly higher in early transplant biopsies than in late transplant biopsies (P<0.05). Conclusion. Some hepatocytes of sex-mismatched liver grafts were replaced by “recipient-derived cells” during injury. Such repopulation is more common in the early liver-graft biopsies. The severity of acute cellular rejection appears to have no effect on the rate of recipient-derived repopulation.


The American Journal of Gastroenterology | 1999

Colorectal adenomateous polyps and Helicobacter pylori infection.

Ahmet Aydin; Zeki Karasu; Aysin Zeytinoglu; Kamil Kumanlioglu; Tijen Özacar

1. Gumber SC, Chopra S. Hepatitis C: A multifaced disease. Review of extrahepatic manifestations. Ann Intern Med 1995; 23:615–20. 2. Linnen J, Wages J, Zhang-Keck ZY, et al. Molecular cloning and disease association of hepatitis G virus: A transfusiontransmissible agent. Science 1996;271:505–8. 3. Misiani R, Mantero G, Bellavita P, et al. GB virus C infection in patients with type II mixed cryoglobulinemia. Ann Intern Med 1997;127:891–4. 4. Zehender G, Galli M, Monti G. GB virus C infection in patients with type II mixed cryoglobulinemia. Ann Intern Med 1998; 128:779 (letter). 5. N. Campo, R. Brizzolara, N. Sinelli, et al. Hepatitis C virus (HGV) infection prevalence in intravenous drug user patients: Relationship with immunodeficiency virus (HIV) and hepatitis C virus coinfection. Ital J Gastroenterol Hepatol 1997;29(suppl 2):A94 (abstract).


Transplantation Proceedings | 2008

Association between hepatitis B and hepatocellular carcinoma recurrence in patients undergoing liver transplantation.

M. Kiyici; M. Yilmaz; Murat Akyildiz; Cigdem Arikan; Unal Aydin; Deniz Sigirli; Deniz Nart; Funda Yilmaz; Tijen Özacar; Zeki Karasu; Murat Kilic

BACKGROUND/AIMS Hepatitis B virus (HBV) and hepatocellular carcinoma (HCC) recurrences affect both patient and graft survivals post-orthotopic liver transplantation (OLT) in HBV patients with HCC. We analyzed the relationship between HBV and HCC recurrence in a large cohort of HBV-OLT patients with versus without HCC. METHODS Two hundred eighty-seven HBV patients with OLT (72 also with HCC) were included in the study. Mean follow-up in the post-OLT period was 31.7 +/- 24.7 (range, 3-119) months. RESULTS Post-OLT HBV recurrence observed in 10.1% of patients was more prevalent among the HCC group; 23.6% versus 5.5% in patients with and without HCC, respectively. The mean interval for the development of HBV recurrence was 39.5 +/- 28.5 (range, 2-99) months. Among 72 HCC patients, 8 patients (11.1%) had recurrent HCC, and 7 of them also had HBV recurrence. The mean interval for the development of HCC recurrence was 11.2 +/- 7.85 (range, 2-23) months after OLT. OLT patients with HCC with tumors exceeding the Milan criteria had worse 1-, 3-, and 5-year survival rates than patients with HCC meeting the Milan criteria. HBV and HCC recurrence-free survivals were significantly lower in patients with HCC and HBV recurrence, respectively. In the 7 patients with both HCC and HBV recurrence, mean HBV recurrence time was 9.42 +/- 6.75 months and mean HCC recurrence time was 9.57 +/- 6.75 months. There was a strong correlation between HBV and HCC recurrence times. Cox proportional hazards regression analysis showed that only HCC recurrence was a significant independent predictor of HBV recurrence (P < .001; hazard ratio [HR] = 26.94; 95% confidence interval [CI] = 10.81-67.11). On the other hand, HBV recurrence (P = .013; HR = 5.80; 95% CI = 1.45-23.17) and nodule count (P = .014; HR = 13.08; 95% CI = 1.70-100.83) were significant predictors of HCC recurrence. CONCLUSIONS HBV and HCC recurrences demonstrate a close relationship in patients with OLT.


Transplantation Proceedings | 2003

Hemophagocytic syndrome after living-related liver transplantation

Zeki Karasu; Murat Kilic; S. Cagirgan; E. Lebe; F. Yilmaz; Tolga Demirbas; Yaman Tokat

Hemophagocytic syndrome (HPS) is a life-threatening hematological disorder in immunocompromised patients. Although the number of patients with HPS following liver transplantation is scarce the outcome is usually fatal. We report a patient who developed HPS following living-related liver transplantation (LRLT) and was treated successfully by a combination of intravenous (IV) immunoglobulin (Ig) and granulocyte colony-stimulating factor (GCSF).

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