Yazar "Yilmaz, Dervis Mansuri" seçeneğine göre listele

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    Non-Detection of HCMV Total Genomic DNA in Human Glioma Cells Genome
    (Turkish Neurosurgical Soc, 2024) Gokturk, Dilek; Alkis, M. Damla Ozdemir; Yilmaz, Dervis Mansuri
    AIM: To demonstrate if the human cytomegalovirus (HCMV) genome, that is involved in the pathogenesis of gliomas, is part of the genomic DNA of glioma cells or not. MATERIAL and METHODS: The study included U87MG glioblastoma cell culture and tumor samples from glioma patients. The genomic DNA of tumor samples and U87MG cells were extracted and real-time quantitative PCR was used to assess the presence of the human cytomegalovirus genomic DNA. RESULTS: Consequently, HCMV positivity was not detected in the tumor and cell line genomic DNA under the aforementioned experimental conditions. CONCLUSION: We found that the genomic DNA of all the samples was negative for HCMV genomic DNA. Thus, HCMV could not be detected in human glioma tumors and we put forward that HCMV genomic DNA was not incorporated into the genomic DNA of glioma cells. Thus, total viral DNA is not involved in the pathogenesis of glioma; however, small viral particles or specific genes might be incorporated into the genomic DNA of glioma cells, leading to cancer development. This prompts further studies for verification.
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    The Effect of Ascorbic Acid over the Etoposide- and Temozolomide-Mediated Cytotoxicity in Glioblastoma Cell Culture: A Molecular Study
    (Turkish Neurosurgical Soc, 2018) Gokturk, Dilek; Kelebek, Haşim; Ceylan, Seda; Yilmaz, Dervis Mansuri
    AIM: Glioblastoma (GBM) is one of the lethal central nervous system tumors. One of the widely used chemical agents for the treatment of glioblastoma is temozolomide. It is an orally administered, deoxyribonucleic acid (DNA) alkylating agent. DNA alkylation triggers the death of tumor cells. However, some tumor cells are able to repair this type of DNA damage and thus lower the therapeutic effect of temozolomide. Laboratory and clinical studies indicate that temozolomide's anticancer effects might be strengthened when combined with other chemotherapeutic agents like etoposide or antioxidant agents like ascorbic acid. In this study, we aimed to evaluate the cytotoxic and oxidative stress effects of ascorbic acid (1000 mu M), temozolomide (100 mu M) and etoposide (25 mu M) agents alone and in dual and triple combinations in a glioblastoma U87 MG cell culture. MATERIAL and METHODS: The cytotoxic and oxidative stress effects were investigated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis methods. RESULTS: Cytotoxicity tests showed that etoposide, temozolomide, etoposide+ascorbic acid, temozolomide+ascorbic acid, temozolomide+etoposide and temozolomide+etoposide+ascorbic acid combinations have anti-proliferative effects. The maximum anti-proliferation response was observed in the temozolomide+etoposide+ascorbic acid-added group. Similarly LCMS/MS analyses showed that minimum oxidative DNA damage occurred in the temozolomide+etoposide+ascorbic acid-added group. CONCLUSION: Ascorbic acid decreases the cytotoxic and genotoxic effect of etoposide and etoposide-temozolomide combination but it has no meaningful effect on temozolomide's toxicity.