Yazar "Tekeli, Ibrahim O." seçeneğine göre listele

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    Determination of selected antibiotics in farmed fish species using LC-MS/MS
    (Wiley, 2017) Yipel, Mustafa; Kurekci, Cemil; Tekeli, Ibrahim O.; Metli, Murat; Sakin, Fatih
    The aim of the study was to monitor the occurrence of 37 antibiotics from different classes including fluoroquinolone, tetracycline, macrolide, sulphonamide, penicillin, amphenicol and cephalosporin in three different farmed fish species (n=75; rainbow trout, see bass, gilthead see bream) from five cities in Turkey. A method for LC-MS/MS was optimized and validated to assess these antibiotics. As a result, 25 samples showed contamination with at least one antibiotic residue. The most detected antibiotics were norfloxacin (NOR) (18.7%), marbofloxacin (MAR) (12%), tetracycline (TC) (10.7), danofloxacin (DAN) (9.3%), oxytetracycline (OTC) (9.3%), tilmicosin (TLM) (8%) and enrofloxacin (ENR) (6.7%). A total of 17.3% of samples examined were found to be contaminated with residues exceeding the maximum residue limits (MRLs). The results indicate that antibiotics are frequently used in aquaculture production without the lack of knowledge. This study also revealed that the consumption of farmed fish could produce a public health concern as the level of residues for some antibiotics was much higher than MRLs.
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    Öğe
    Proapoptotic Effect of Hypericum perforatum (St. John's Wort) Extract in Human Colorectal Adenocarcinoma Cell Line HT29
    (Asian Network Scientific Information-Ansinet, 2020) Yegani, Arash A.; Istifli, Erman S.; Tekeli, Ibrahim O.; Sakin, Fatih; Kaplan, Halil M.
    Background and Objective: Hypericum perforatum (HP) is known to have therapeutic effects in many types of cancer. Although the active substances hypericin and hyperforin in the composition of HP have been shown to exert apoptotic effects in cancer cell lines, research into the anticancer effects of the total extract of HP is meagre. The aim of this study was to investigate the proapoptotic effect of HP on human colorectal adenocarcinoma cell line HT29. Materials and Methods: HT29 cells (5 X 10(4) cells cm(-2)) were exposed to 99.2% medium and pharmacologically effective concentration of HP extract (0.8%) for 48 h. Cells were then washed in phosphate buffered saline PBS and lysed in RIPA buffer for 15 min on ice followed by centrifugation at 15000 rpm for 20 min and supernatants were taken and pellets were discarded. ELISA test was used to examine the expression and activity of cleaved caspase-3, Bax, Bcl-2, Wee1, GADD153, GRP78 and AIF proteins in HT29 cells. Results: ELISA test results indicated that the activities of proapoptotic proteins Bax, cleaved-caspase 3, Wee1, GRP78, GADD153 and AIF in human HT29 cell line were significantly increased in 48 h treatment with HP extract at 0.8% concentration. On the other hand, the activity of Bcl-2 was observed to decrease significantly. Conclusion:The results implicated that the HP extract in its original form effectively induces proapoptotic alterations in HT29 cells and a possible mutual signaling between the proapoptotic Wee1, GRP78, GADD153, AIF, Bax and cleaved caspase-3 proteins can contribute to this effect.