Molecular Biology and Genetics / Moleküler Biyoloji ve Genetik

Permanent URI for this collectionhttps://hdl.handle.net/11147/9

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End date: 2009Publisher: search.filters.publisher.Taylor and Francis Ltd.

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Now showing 1 - 6 of 6
  • Article
    Citation - WoS: 16
    Citation - Scopus: 16
    Multidrug Resistance Mediated by Mrp1 Gene Overexpression in Breast Cancer Patients
    (Taylor and Francis Ltd., 2009) Abaan, Ogan Demir; Mutlu, Pelin Kaya; Baran, Yusuf; Atalay, Can; Gündüz, Ufuk
    Multidrug resistance (MDR) is a serious handicap towards the effective treatment of breast cancer patients. One of the most prevalent MDR mechanisms is through the overexpression of genes coding the proteins called Multidrug Resistance-associated Proteins (MRPs). The aim of this study was to investigate the expression of MRP1 in tumor tissues from breast cancer patients. In this study, a semi-quantitative RT-PCR approach was utilized. Our results suggest that MRP1 overexpression can mediate MDR in patients. Pre-evaluation of the level of such MDR mediators before chemotherapy can increase the efficacy of the treatment.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Docetaxel Enhances the Cytotoxic Effects of Imatinib on Philadelphia Positive Human Chronic Myeloid Leukemia Cells
    (Taylor and Francis Ltd., 2009) Güçlüler, Gözde; Baran, Yusuf
    Chronic myelogenous leukemia (CML) results from a translocation between chromosomes 9 and 22 which generates BCR/ABL fusion protein and characterized by uncontrolled proliferation of immature white blood cells. Imatinib, a molecularly targeting anticancer agent, is used widely for the treatment of CML and showed significant activity in chronic and accelerated phases but much less in blast crisis phase. The resistance to imatinib especially in blast crisis phase is recognized as a major problem in the treatment of CML patients. Docetaxel is shown to arrest cells in G2/M phase of the cell cycle which makes cells more sensitive to chemo- and radiotherapy. In this study, we aimed to increase chemosensitivity of human K562 CML cells to imatinib in combination with docetaxel. Taken together, our results showed that the combination of imatinib and docetaxel decreased cellular proliferation and increased apoptosis in human K562 chronic myeloid leukemia cells as compared to any agent alone. Imatinib and docetaxel induced apoptosis through caspase-3 enzyme activity and mitochondrial membrane potential.
  • Article
    Citation - WoS: 86
    Citation - Scopus: 102
    Total Antioxidant Activity and Total Phenolic Contents in Different Turkish Eggplant (solanum Melongena L.) Cultivars
    (Taylor and Francis Ltd., 2009) Ökmen, Bilal; Şığva, Hasan Özgür; Mutlu, Sevgi; Doğanlar, Sami; Yemenicioğlu, Ahmet; Frary, Anne
    In this study, total water soluble antioxidant activity and phenolic content of 26 eggplant (Solanum melongena L.) cultivars were investigated. Total water soluble antioxidant activity of the cultivars varied from 2664 to 8247 molTrolox/kg, which is a 3.1-fold difference. Cultivars also showed significant variation for total phenolic contents ranging from 615 to 1376 mg/kg, a 2.2-fold difference. The two traits were significantly correlated and results of this study suggested that breeders can use the information to develop eggplant cultivars with high antioxidant activity.
  • Article
    Citation - WoS: 12
    Citation - Scopus: 18
    Hematoprotective Effect of Seleno-L on Cyclophosphamide Toxicity in Rats
    (Taylor and Francis Ltd., 2009) Ayhancı, Adnan; Yaman, Suzan; Appak, Sıla; Güneş, Sibel
    Cyclophosphamide (CP) is a widely used antineoplastic drug that causes toxicity in the normal cell due to its metabolites. The major drawback of this drug is an undesirable myelosuppression. Selenium (Se) is a potent nutritional antioxidant that carries out biological effects by its incorporation into selenoproteins, such as glutathione peroxidase (GPx). The possible protective effects of seleno-l-methionine (SLM) against CP-related toxicity of blood cells and bone marrow of rats were investigated in this study. Intraperitoneal (i.p) administration of 50, 100, or 150mg/kg of CP caused, in a dose-dependent manner, reductions in the number of leukocytes (78, 89, and 92%, respectively), thrombocytes (22, 33, and 52%, respectively), and bone marrownucleated cells (72, 90, and 94%, respectively). The groups that had CP treatment alone were killed 3 days after the CP injection. For the groups having CPSLM, SLM (0.4 or 0.8mg/kg i.p) administration was started 3 days earlier than the CP administration and continued to the end of the experiment (6 days). On day 4, the animals were weighed again, relative doses of CP were estimated, and CPSLM was administered together. On day 7, blood samples were collected and bone marrow of animals were resected under anesthesia. The results indicated that treatment of rats within a select dose range of SLM could reduce CP-induced toxicity on blood cells and bone marrow.
  • Article
    Citation - WoS: 23
    Citation - Scopus: 26
    Development of Practical Hplc Methods for the Separation and Determination of Eggplant Steroidal Glycoalkaloids and Their Aglycones
    (Taylor and Francis Ltd., 2008) Eanes, Ritchie C.; Tek, Neslihan; Kırsoy, Öyküm; Frary, Anne; Doğanlar, Sami; Almeida, Adelia E.
    A practical set of HPLC methods was developed for the separation and determination of the eggplant steroidal glycoalkaloids, solanine, chaconine, solasonine, solamargine, and their aglycones, solasodine and solanidine. A gradient method was initially developed, but proved to be neither robust nor practical. Three separate isocratic methods using acetonitrile and ammonium dihydrogen phosphate were developed and shown to be more repeatable, less subject to fluctuations in mobile phase composition, and less time consuming. The effect of adjusting buffer pH, column temperature, and buffer type (triethylammonium phosphate vs. ammonium dihydrogen phosphate) were evaluated. It was also discovered that, by addition of 10% methanol to the acetonitrile portion of the mobile phase, more control over the separations was possible. The use of methanol as a mobile phase entrainer greatly improved separations in some cases and its effectiveness was also dependent upon column temperature. Assessments of the method recovery, limit of detection, and limit of quantitation were made using extracts from S. melongena and S. linnaeanum.
  • Article
    Citation - WoS: 33
    Citation - Scopus: 35
    Upregulation of Multi Drug Resistance Genes in Doxorubicin Resistant Human Acute Myelogeneous Leukemia Cells and Reversal of the Resistance
    (Taylor and Francis Ltd., 2007) Baran, Yusuf; Gür, Bala; Kaya, Pelin; Ural, Ali Uğur; Avcu, Ferit; Gündüz, Ufuk
    The major problem in the treatment of acute myeloid leukemia (AML) patients results from multidrug resistance to administered anticancer agents. Drug resistance proteins, MDR1 and MRP1, which work as drug efflux pumps, can mediate the multidrug resistance of human leukemia cells. In this study, the mechanisms of resistance to doxorubicin-induced cell death in human HL60 AML cells were examined. Continuous exposure of cells to step-wise increasing concentrations of doxorubicin resulted in the selection of HL60/DOX cells, which expressed about 10.7-fold resistance as compared to parental sensitive cells. The expression analyses of MRP1 and MDR1 drug efflux proteins in doxorubicin-sensitive and -resistant HL60 cells revealed that there was an upregulation of MRP1 gene in HL60/DOX cells as compared to parental sensitive cells. On the other hand, while there was no expression of MDR1 gene in parental cells, the expression of MDR1 gene was upregulated in HL60/DOX cells. HL60/DOX cells also showed cross-resistance to cytosine arabinoside (Ara-c). This resistance was reversed by a combination therapy of Ara-c and cyclosporine A. However, the expression levels of CD15 and CD16 surface markers were significantly decreased in HL60/DOX cells.