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    Protective effect of selenium on intussusception-induced ischemia/reperfusion intestinal oxidative injury in rats
    (Tubitak Scientific & Technical Research Council Turkey, 2010) Akman, Hulya; Somuncu, Salih; Dikmen, Gunnur; Ayva, Sebnem; Soyer, Tutku; Dogan, Pakize; Cakmak, Murat
    Aim: To evaluate the protective effect of selenium on intestinal ischemia-reperfusion injury due to intussusception. Materials and methods: Forty Wistar albino rats were allocated to 4 equal groups (n = 10) After anesthetization, 2 cm of intestinal segment, 20 cm proximal to the ileocecal valve, was removed in the control group (CG) In the intussusception group (ING), intussusception was performed 20 cm proximal to the ileocecal valve by pushing the proximal intestinal segment distally with a stylet, and 2 cm of intestinal segment was removed 4 h later Intussusception was reduced and a 2 cm segment was removed after another 4 h period in the intussusception-reduction group (IRG). The selenium group (SG) received 0.2 mg kg(-1) of selenium in 10 mL of 0 9% NaCl solution intraperitoneally 20 min before reduction and segments were removed 411 thereafter Intestinal tissues were evaluated for histopathological grades and oxidative injury markers Results: Histopathologic evaluations among the 4 groups did not reveal a significant difference (P > 0 05) Although catalase activity was decreased in all groups, increased activity was found in SG compared with IRG (P < 0 05) GSH-Px and SOD activities were also found to have decreased in ING and IRG (P < 0 05) CG and SG had no difference in GSH-Px and SOD activities (P > 0 05) Malondialdehyde (MDA) activities did not differ between CG and SG, but the MDA level was Increased in ING and IRG when compared with CG (P < 0 05) Conclusion: Although selenium prevents oxidative injury by increasing the antioxidant enzyme activity in experimental intussusception, minim effects on histopathologic findings were not detected
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    Öğe
    RADIOSENSITIVITY OF HUMAN BRONCHIAL EPITHELIAL CELLS WITH GENETIC ALTERATIONS
    (Gazi Univ, Fac Med, 2005) Dikmen, Z. Gunnur; Dikmen, Erkan; Dogan, Pakize
    Purpose: To analyze the proliferation rates and the radiosensitivity of human bronchial epithelial cells (HBECs) with genetic alterations including human telomerase reverse transcriptase (hTERT), Cdk4 (cyclin dependent kinase 4), knockdown p53 and mutant K-ras overexpression. Materials and Methods: HBECs obtained from human bronchus specimens were placed into short-term culture and were serially transfected with retroviral constructs containing Cdk4 and hTERT, resulting in continuously growing immortalized normal human bronchial epithelial cell lines. These cell lines were used to produce knock-down p53, mutant K-ras and knockdown p53 plus K-ras expressing cell lines; the proliferation rates and the radiosensitivity of these cell lines were evaluated. The control cells and the Cdk4, hTERT, knockdown p53 and K-ras expressing cells were irradiated (1 Gy-10 Gy) and the fraction survival was determined 1 week later. Results: The proliferation rates of the cells expressing both knockdown p53 and K-ras were higher than those of the other cell lines and show a loss of contact inhibition in vitro. The HBECs infected with both knockdown p53 and mutant K-ras were more radioresistant compared to cells infected with only mutant K-ras or knockdown p53. Conclusion: HBECs expressing knockdown p53 in addition to mutant Kras have higher proliferation rates and additionally they lose the ability of growth arrest in response to DNA damage signals such as irradiation.