Browsing by Author "Pehlivan, M"

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    The Cytotoxic Effect of Polygonium cognatum and Chemotherapeutic Effect of Doxorubicin on Glioblastoma Cells
    Pehlivan, M; Çöven, HIK; Çerçi, B; Eldem, A; Öz, T; Savlak, N; Soyöz, M; Pirim, I
    Objective: Glioblastoma multiforme (GBM) is an aggressive malignant brain tumor common in adults. Owing to the present difficulty in treating GBM, developing alternative methods is of utmost importance. Recently, the efficacy of various plant extracts in cancer treatment have been evaluated. Polygonum cognatum (P. cognatum) known as 'Madimak' is used in herbal medicine in Turkey. Methods: In this study, we investigated the cytotoxity of P. cognatum in the treatment of glioblastoma and its contribution to the effectiveness of doxorubicin (DXR). In the U87 cell line of the P. cognatum and doxorubicin administered at different doses, IC50 doses were determined using the 2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide (XTT) method and the effects of combined administration at these doses were examined (respectively 10-125 mu g/ml and 0.1-10 mu g/ml at 24, 48, and 72 h). Results: P. cognatum extract decreased the cell viability of U87 cells in a time and concentration-dependent manner. It also increased the apoptotic effectiveness of DXR in U87 cells. Conclusion: This is the first preliminary study that investigates the treatment of P. cognatum on glioblastoma in vitro. Further studies are required to investigate the effect of the extract on healthy human cells and to understand signaling pathways.
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    Factors influencing engraftment in autologous peripheral hematopoetic stem cell transplantation (PBSCT)
    Ergene, U; Çagirgan, S; Pehlivan, M; Yilmaz, M; Tombuloglu, M
    Autologous peripheral blood stem cells transplantation (PBSCT) is a therapeutic option which can be used in various hematological neoplastic disorders; and it can prolong disease free survival and total survival and at times it may be curative. In this study, we investigated variables influencing PBSCT in 91 patients who had undergone PBSCT between 1998 and 2002 in our center, retrospectively. PBSC collection was performed after mobilization with G-CSF or chemotherapy plus growth factor. Only high dose chemotherapy was used for conditioning regimes. The median number of CD34+ was 11.5 x 10(6)/kg. Posttransplant neutrophil engraftment (> 500/mu L) was requiring a median of 10 days, it was 13 days for platelet engraftment (> 20,000/mu L). For neutrophil and platelet engraftment, we investigated; sex, age, diagnosis and CD34+ cells, the time interval between diagnosis and transplantation, number of apheresis, conditioning regime, growth factor initiation day as independent variables. In univariate analysis CD34+ cell number (> 10 x 10(6)/kg), time interval more than one year between diagnosis and transplantation and BEAM conditioning was found to be significant for neutrophil engraftment. But in multivariate analysis none of them was found to be significant. For platelet engraftment in univariate analysis CD34+ cell number (> 7 x 10(6)/kg), primary diagnosis of multiple myeloma initiation day of growth factor (> 2 day) was found to be significant. In multivariate analyses only CD34+ cell count was found to be significant (p = 0.005). In conclusion, as in previous studies we found that the only predictor of engraftment kinetics was CD34+ cell count. (c) 2006 Published by Elsevier Ltd.
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    Efficacy of first-line CDK 4-6 inhibitors in premenopausal patients with metastatic breast cancer and the effect of dose reduction due to treatment-related neutropenia on efficacy: a Turkish Oncology Group (TOG) study
    Yildirim, HC; Kapar, C; Koksal, B; Seyyar, M; Sanci, PC; Guliyev, M; Perkin, P; Buyukkor, M; Yaslikaya, S; Majidova, N; Keskinkilic, M; Ozaskin, D; Avci, T; Gunes, TK; Arcagok, M; Topal, A; Keskin, GSY; Kavgaci, G; Yildirim, N; Celayir, OM; Avci, N; Aslan, F; Alkan, A; Erciyestepe, M; Cengiz, M; Pehlivan, M; Gulmez, A; Beypinar, I; Tuylu, TB; Kayikcioglu, E; Chalabiyev, E; Turhal, S; Guzel, HG; Ayas, E; Sahbazlar, M; Dulgar, O; Demir, H; Yavuzsen, T; Bayoglu, V; Salim, DK; Ozturk, B; Ozdemir, F; Kara, O; Oksuzoglu, B; Bal, O; Demirci, NS; Yilmaz, M; Cabuk, D; Aksoy, S
    The only phase 3 study on the effectiveness of CDK 4-6 inhibitors in first-line treatment in premenopausal patients with hormone receptor (HR) positive, HER2 negative metastatic breast cancer is the MONALEESA-7 study, and data on the effectiveness of palbociclib is limited. Data are also limited regarding the effectiveness of CDK 4-6 inhibitors in patients whose dose was reduced due to neutropenia, the most common side effect of CDK 4-6 inhibitors. In our study, we aimed to evaluate the effectiveness of palbociclib and ribociclib in first-line treatment in patients with premenopausal metastatic breast cancer and the effect of dose reduction due to neutropenia on progression-free survival. Our study is a multicenter, retrospective study, and factors affecting progression-free survival (PFS) were examined in patients diagnosed with metastatic premenopausal breast cancer from 29 different centers and receiving combination therapy containing palbociclib or ribociclib in the metastatic stage. 319 patients were included in the study. The mPFS for patients treated with palbociclib was 26.83 months, and for those receiving ribociclib, the mPFS was 29.86 months (p = 0.924). mPFS was 32.00 months in patients who received a reduced dose, and mPFS was 25.96 months in patients who could take the initial dose, and there was no statistical difference (p = 0.238). Liver metastasis, using a fulvestrant together with a CDK 4-6 inhibitor, ECOG PS 1 was found to be a negative prognostic factor. No new adverse events were observed. In our study, we found PFS over 27 months in patients diagnosed with premenopausal breast cancer with CDK 4-6 inhibitors used in first-line treatment, similar to post-menopausal patients. We did not detect any difference between the effectiveness of the two CDK 4-6 inhibitors, and we showed that there was no decrease in the effectiveness of the CDK 4-6 inhibitor in patients whose dose was reduced due to neutropenia.