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Dive into the research topics where Muhit Ozcan is active.

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Featured researches published by Muhit Ozcan.


Journal of Viral Hepatitis | 2004

Lamivudine prophylaxis for prevention of chemotherapy-induced hepatitis B virus reactivation in hepatitis B virus carriers with malignancies.

Ramazan Idilman; Mutlu Arat; Ender Soydan; Murat Törüner; Irfan Soykan; Hakan Akbulut; Onder Arslan; Muhit Ozcan; Ahmet R Turkyilmaz; Mithat Bozdayi; Selim Karayalcin; D. H. Van Thiel; Ali Özden; Meral Beksac; Hamdi Akan

Summary.  Although hepatitis B virus (HBV) reactivation in HBV carriers undergoing immunosuppressive therapy is clearly documented, the role of antiviral prophylaxis in such individuals is still controversial. The aim of this study was to determine the efficacy of lamivudine prophylaxis in HBV carriers with haemato/oncological malignancies, who receive chemotherapy. Eighteen HBV carriers with malignancy, who were candidates for chemotherapy, were enrolled. Eight subjects (three with leukaemia, four with lymphoma and one with multiple myeloma) were enrolled for prophylactic lamivudine therapy. The remaining 10 patients (six with leukaemia, three with lymphoma and one with breast cancer) were not treated with lamivudine and were used as a control. Lamivudine was administered beginning on the same day as the chemotherapy and was maintained for a year after chemotherapy was discontinued. No HBV‐related mortality was observed in either group. In the lamivudine‐treated group, none of the subjects had clinical, biochemical or serological evidence of HBV reactivation during the time they were receiving chemotherapy and after their chemotherapy was discontinued. In contrast, five of the 10 HBV carriers not receiving lamivudine therapy experienced a reactivation of HBV infection. This reactivation of HBV was observed during the chemotherapy in four with one individual experiencing a HBV activation 12 months after chemotherapy was discontinued. No lamivudine‐related major adverse effects were observed. Hence prophylactic lamivudine treatment in HBV carriers with haemato/oncological malignancy receiving chemotherapy prevents chemotherapy‐induced HBV reactivation.


British Journal of Haematology | 2002

Mobilization of peripheral blood stem cells with chemotherapy and recombinant human granulocyte colony-stimulating factor (rhG-CSF): a randomized evaluation of different doses of rhG-CSF.

Taner Demirer; Meltem Ayli; Muhit Ozcan; Nazan Günel; Rauf Haznedar; Mehmet Daglı; Turgay Fen; Yasemin Genç; Suleyman Dincer; Onder Arslan; Gunhan Gurman; S. Demirer; Gülsüm Özet; Akin Uysal; Nahide Konuk; Osman Ilhan; Haluk Koç; Hamdi Akan

Summary. To date, no randomized study has compared different doses of recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) following submyeloablative mobilization chemotherapy. Therefore, we evaluated the effect of different doses of rhG‐CSF following mobilization chemotherapy on yields of CD34+ peripheral blood stem cells (PBSC). Fifty patients were randomized to receive 8 (n = 25) versus 16 µg/kg/d (n = 25) of rhG‐CSF following mobilization chemotherapy. The median number of CD34+ cells collected after 8 µg/kg/d of rhG‐CSF was 2·36 × 106/kg (range, 0·21–7·80), compared with 7·99 (2·76–14·89) after 16 µg/kg/d (P < 0·001). Twenty out of 25 (80%) patients in the low‐dose and 23 out of 25 (92%) in the high‐dose rhG‐CSF arm underwent high‐dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). Median days to white blood cell engraftment in patients mobilized with 8 µg/kg and 16 µg/kg of rhG‐CSF were 12 (10–20) and 9 (8–11) respectively (P < 0·001). There was no difference between the two groups regarding the other parameters of peritransplant morbidity: days to platelet engraftment (P = 0·10), number of red blood cell (P = 0·56) and platelet transfusions (P = 0·22), days of total parenteral nutrition requirement (P = 0·84), fever (P = 0·93) and antibiotics (P = 0·77), and number of different antibiotics used (P = 0·58). These data showed that higher doses of rhG‐CSF following submyeloablative mobilization chemotherapy were associated with a clear dose–response effect based on the collected cell yields. Based on the parameters of peritransplant morbidity, 8 µg/kg/d was as effective as 16 µg/kg/d except for a rapid neutrophil engraftment in the high‐dose arm. Therefore, in routine clinical practice, despite some advantage in the use of higher doses of rhG‐CSF, lower doses may be used for PBSC collections following chemotherapy‐based mobilization regimens in this cost‐conscious era.


European Journal of Gastroenterology & Hepatology | 2005

Thrombophilic gene mutations in cirrhotic patients with portal vein thrombosis.

Ozlem Erkan; A.M. Bozdayi; Selcuk Disibeyaz; Dilek Oguz; Muhit Ozcan; Kadir Bahar; Selim Karayalcin; Ali Özden; Hakan Bozkaya; Cihan Yurdaydin; Ozden Uzunalimoglu

Objective Thrombophilic gene mutations have been reported to be associated with the formation of portal vein thrombosis (PVT). This study aimed to investigate the role of thrombophilic gene mutations in cirrhotic patients with PVT. Patients and methods A total of 74 cirrhotic patients (17 with PVT, 57 without PVT), and 19 non-cirrhotic patients with PVT and 80 healthy controls were included. Factor V Leiden G1691A, prothrombin G20210A and methylenetetrahydrofolate reductase C677T mutations were analysed by restriction fragment length polymorphism. Results Aetiologies and Child–Pugh distribution of cirrhotic patients with and without PVT were similar. Five of 17 (29%) of cirrhotic patients with PVT but only two of 57 (3.5%) of cirrhotics without PVT, five of 80 (6%) of controls and none of the 19 non-cirrhotic patients with PVT had factor V Leiden G1691A mutation (P<0.05). Prothrombin G20210A mutation was found in five (29%) cirrhotic patients with PVT while only two (3.5%) cirrhotic patients without PVT, one (5%) non-cirrhotic patient with PVT and two (2.5%) controls had this mutation (P<0.05). The frequency of the homozygote methylenetetrahydrofolate reductase 677C-T mutation was similar in all four groups. Conclusions Inherited thrombophilic gene mutations appear to increase the risk of PVT formation in cirrhotic patients but not in patients without liver disease in a cohort of Turkish patients.


Bone Marrow Transplantation | 1997

Hepatitis B virus infection in allogeneic bone marrow transplantation

C. Üstün; Haluk Koç; S Karayalçın; Gülen Akyol; Gunhan Gurman; Osman Ilhan; Hamdi Akan; Muhit Ozcan; Onder Arslan; Nahide Konuk; Akin Uysal; Meral Beksac

Fourty-four patients who underwent allogeneic bone marrow transplantation (alloBMT) were studied for hepatitis B virus (HBV)-related complications. The mean follow-up period was 15.3 months. Positivity for HBV surface antigen (HBsAg) was observed in 10 patients (22.7%) throughout the study. Four of the 10 patients were HBsAg carriers before alloBMT, while the remaining six became HBsAg(+) after alloBMT. During the follow-up period (from 6 months to 45 months), an elevation in serum ALT activity was observed in the four carriers when immunosuppression was reduced or withdrawn. All of the four HBsAg carriers developed hepatitis, but none of them died of liver failure due to HBV. Only one death due to GVHD and diabetic ketoacidosis was observed in this group. Two of the four carriers received marrow from anti-HBs positive donors and one of them cleared HBsAg from his serum via adoptive immunity 8 months after transplantation. The remaining six patients acquired HBV after alloBMT, but we were unable to demonstrate the source of HBV. Five of them had a moderate increase in serum ALT activity while the other patient had a normal ALT. Two patients seroconverted to anti-HBs spontaneously. Two patients died during the follow-up, one due to intracranial hemorrhage and the other due to GVHD and accompanying pulmonary infection. The rest of the study group (34 patients) remained HBsAg(−) throughout the study. Two of them had an HBsAg(+) donor, but neither developed HBV infection in their follow-up period. The acquisition rate of HBV infection was relatively low in recipients who were positive for anti-HBs compared to those who were negative for anti-HBs (8 vs 19%). Anti-HBs positivity remained for a longer period in recipients who received marrow from anti-HBs positive donors compared to those recipients who had anti-HBs negative donors (median 12 vs 3 months). We think that HBV is a frequent cause of liver dysfunction in alloBMT patients where HBV infection is endemic. Whether the disease is in the form of reactivation of HBsAg-positive recipients, or is acquired from unknown sources in recipients who never had contact with the virus, the course of the disease is not fatal. Silent serologic changes can be demonstrated if viral serologic markers are sought serially. Among them, the disappearance of serum anti-HBs may be important as it increases the risk of HBV contamination in recipients.


Circulation | 2003

Elevated Whole-Blood Tissue Factor Procoagulant Activity as a Marker of Restenosis After Percutaneous Transluminal Coronary Angioplasty and Stent Implantation

Eralp Tutar; Muhit Ozcan; Mustafa Kilickap; Sadi Gulec; Omer Aras; Gülgün Pamir; Derviş Oral; Luke Dandelet; Nigel S. Key

Background—Experimental data suggest that tissue factor (TF) may induce neointimal hyperplasia after arterial injury. In this study, we investigated the hypothesis that elevated levels of TF in the circulation contribute to the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA) or stent implantation. Methods and Results—Whole-blood TF procoagulant activity (TF-PCA) was measured using a previously described assay before, at 3 hours after, and at 24 hours after the intervention in 61 patients with stable angina undergoing PTCA (n=20) or stent implantation (n=41). Coronary angiography was performed 4 to 6 months after the intervention, and luminal narrowing ≥50% was defined as restenosis. Whole-blood TF-PCA levels did not correlate with intracellular monocyte tumor necrosis factor-&agr; expression, a marker of activation of these cells. Baseline levels and time course of whole-blood TF-PCA after the intervention were compared in patients who did or did not subsequently develop restenosis. Whole-blood TF-PCA levels did not change significantly in the 24 hours after either intervention. However, in both the PTCA and stent groups, initial TF-PCA was significantly higher in patients who subsequently developed restenosis (P =0.018 and 0.039 compared with those who did not develop restenosis for PTCA and stent groups, respectively). Conclusions—Higher baseline values of whole-blood TF-PCA may be a predictor of restenosis after PTCA and stent implantation.


Bone Marrow Transplantation | 2004

Administration of granulocyte-colony-stimulating factor for allogeneic hematopoietic cell collection may induce the tissue factor-dependent pathway in healthy donors.

P Topcuoglu; Mutlu Arat; K Dalva; Muhit Ozcan

Summary:The hypercoagulable state caused by the use of recombinant human granulocyte colony-stimulating factor (rhG-CSF) has been cited in anecdotal reports. Since tissue factor (TF) is the main initiator of the coagulation cascade, we examined if rhG-CSF had an inductive effect on the TF-dependent pathway in 18 healthy donors receiving rhG-CSF (10 μg/kg/day × 5 days) for peripheral blood progenitor cell mobilization. After rhG-CSF, there were increases both in TF antigen (TF:Ag) (P=0.01) and TF procoagulant activity (TF:PCA) (P=0.06) plasma levels and in TF:Ag cytofluorimetric expression on CD33 (+) cells (P=0.04). Mean activities of FVIII and vWF also increased significantly. Thrombin time was slightly prolonged (P=0.06) due to significant increases in plasma D-dimer levels. In addition, while FIX activity remained stable, there were marked reductions in mean plasma FX and FII activities and a slight decrease in FVII activity that resulted in a significant prolongation of prothrombin time within normal ranges. In conclusion, the administration of rhG-CSF led to a ‘prothrombotic state’ via stimulation of TF and increased endothelial markers, such as F VIII and vWF. In the light of these findings, the use of rhG-CSF for stem cell mobilization should be undertaken cautiously in healthy donors with underlying thrombotic risk factors.


Bone Marrow Transplantation | 1999

Autoimmune thrombocytopenia in a patient with small cell lung cancer developing after chemotherapy and resolving following autologous peripheral blood stem cell transplantation.

Taner Demirer; Harika Çelebi; Mutlu Arat; C. Üstün; S Demirer; Imdat Dilek; Muhit Ozcan; Osman Ilhan; Hamdi Akan; Gunhan Gurman; Haluk Koç

A 46-year-old white male with small cell lung cancer (SCLC) limited to the thorax developed autoimmune thrombocytopenic purpura (AITP), following a cyclophosphamide, paclitaxel and G-CSF-containing regimen for peripheral blood stem cell (PBSC) mobilization. AITP associated with small or non-small cell lung cancer has been reported. We considered that the AITP in this case may be a part of paraneoplastic syndrome, which is frequently seen in patients with SCLC. The patient received HDC and autologous PBSC transplantation (APBSCT) for SCLC and the AITP resolved following transplantation, thus supporting the concept of HDC + APBSCT for the treatment of autoimmune diseases.


Transfusion Science | 1999

The impact of the CD34+ cell dose on engraftment in allogeneic peripheral blood stem cell transplantation.

Osman Ilhan; Onder Arslan; Mutlu Arat; Meral Beksac; Hamdi Akan; Muhit Ozcan; Gunhan Gurman; Nahide Konuk; Akin Uysal; Haluk Koç

Forty-five patients who underwent allogeneic peripheral blood stem cell transplantation (PBSCT) were evaluated in order to investigate any relationship between CD34+ cell dose given and hematological recovery. Granulocyte counts > 1.0 x 10(9)/L and platelet > 50 x 10(9)/L were considered as hematological recovery. Three different regimens were used for mobilization, by adjusting the recombinant granulocyte colony stimulating factor (rhG-CSF, Roche) dose. The first group (n = 3), whose donors mobilized with 5 micrograms/kg/d s.c. rhG-CSF received a mean of 5.9 x 10(6)/kg (95% confidence interval for mean (CI); 2.4-9.3) CD34+ cells. The second group (n = 37), mobilized with 10 micrograms/kg/d s.c. rhG-CSF and the third group (n = 5) mobilized with 15 micrograms/kg/d s.c. rhG-CSF, received a mean of 5.7 x 10(6)/kg (95% CI; 4.6-6.75) and 6.56 x 10(6)/kg (95% CI; 4.57-8.55) CD34+ cells, respectively. CD34+ cell dose was 5.82 x 10(6)/kg (95% CI; 4.97-6.68) for all the patients. All patients received rhG-CSF from day +1 until attaining granulocyte count > 1.0 x 10(9)/L for three consecutive days. Median granulocyte and platelet engraftment days for the whole group was 15 (range; 11-44) and 14 (11-54) days respectively. There was a close correlation (r = -0.301, p < 0.05) between the CD34+ cell dose and granulocyte recovery for the whole group. When these analyses were performed separately within groups, this correlation was also found significant for the first group (r = -0.99, p < 0.05) for granulocyte recovery. On the contrary the same analysis did not reach significance for the other groups, nor for platelet recovery for the whole group (r = 0.039, p = 0.821). We calculated a minimum dose of 4 x 10(6)/kg CD34+ cells for a safe alloPBSCT. There was no difference between patients who received more than 5 x 10(6)/kg CD34+ cells, and those who received more than 2 x 10(6)/kg and less than 5 x 10(6)/kg CD34+ cells. In conclusion, we have demonstrated a correlation between the CD34+ cell dose given and faster hematological recovery for alloPBSCT patients.


Journal of Clinical Oncology | 2017

Phosphatidylinositol 3-kinase inhibition by Copanlisib in relapsed or refractory indolent lymphoma

Martin Dreyling; Armando Santoro; Luigina Mollica; Sirpa Leppä; George A. Follows; Georg Lenz; Won Seog Kim; Arnon Nagler; Panayiotis Panayiotidis; Judit Demeter; Muhit Ozcan; Marina Kosinova; Krimo Bouabdallah; Franck Morschhauser; Don A. Stevens; David R. Trevarthen; Marius Giurescu; Lisa Cupit; Li Liu; Karl Köchert; Henrik Seidel; Carol Peña; Shuxin Yin; Florian Hiemeyer; J. Garcia-Vargas; Barrett H. Childs; Pier Luigi Zinzani

Purpose Phosphatidylinositol 3-kinase (PI3K) signaling is critical for the proliferation and survival of malignant B cells. Copanlisib, a pan-class I PI3K inhibitor with predominant activity against PI3K-α and -δ isoforms, has demonstrated efficacy and a manageable safety profile in patients with indolent lymphoma. Patients and Methods In this phase II study, 142 patients with relapsed or refractory indolent lymphoma after two or more lines of therapy were enrolled to receive copanlisib 60 mg intravenously on days 1, 8, and 15 of a 28-day cycle. The primary end point was objective response rate; secondary end points included duration of response, progression-free survival, and overall survival. In addition, safety and gene expression were evaluated. Results Median age was 63 years (range, 25 to 82 years), and patients had received a median of three (range, two to nine) prior regimens. The objective response rate was 59% (84 of 142 patients); 12% of patients achieved a complete response. Median time to response was 53 days. Median duration of response was 22.6 months, median progression-free survival was 11.2 months, and median overall survival had not yet been reached. The most frequent treatment-emergent adverse events were transient hyperglycemia (all grades, 50%; grade 3 or 4, 41%) and transient hypertension (all grades, 30%; grade 3, 24%). Other grade ≥3 events included decreased neutrophil count (24%) and lung infection (15%). High response rates to copanlisib were associated with high expression of PI3K/B-cell receptor signaling pathway genes. Conclusion PI3K-α and -δ inhibition by copanlisib demonstrated significant efficacy and a manageable safety profile in heavily pretreated patients with relapsed or refractory indolent lymphoma.


Clinical Transplantation | 2003

Hepatitis B virus vaccination of recipients and donors of allogeneic peripheral blood stem cell transplantation

Ramazan Idilman; C. Üstün; Selim Karayalcin; Aslihan Aktemel; Ahmet R Turkyilmaz; Muhit Ozcan; Onder Arslan; A. Mithat Bozdayi; David H. Van Thiel; Hamdi Akan

Abstract: Background: The aim of this study was to determine the role of hepatitis B virus (HBV) vaccination as defined by the seroconversion to hepatitis B surface antibody (anti‐HBs) positivity in peripheral blood stem cell transplants.

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Mutlu Arat

Istanbul Bilim University

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