Browsing by Author "Aktas, C"

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    POMC expression of the urothelium of the urinary bladder of mice submitted to pelvic radiation
    Ozbilgin, MK; Aktas, C; Temel, M; Önal, T; Uluer, ET; Vatansever, HS; Kurtman, C
    Objective: Patients who have had pelvic radiotherapy as part of their cancer therapy may develop subsequent urinary bladder injury. The acute changes that the urothelium undergo after radiation are known, but the healing mechanism of the urothelium of the urinary bladder after pelvic radiotherapy is not clearly understood. Proopiomelanocortin (POMC) peptides, which have immunomodulatory effects, are produced locally in sites outside of the central nervous system. This study aims to determine the role of POMC expression in the urothelium during radiation injury. Methods: Twenty-four male Swiss Albino mice were divided into four groups. A single-fractioned 10 Gy of ionizing radiation was applied to the pelvic zone of all mice with Cobalt-60 radiotherapy. The first group 1, which consisted intact animal and not irradiated was the control group, and the second, third, and fourth groups were euthanized after 24 h (Group 2), 48 h (Group 3), and 7 days (Group 4) after irradiation. All bladders were prepared for histochemical analysis using hematoxylin eosin (H&E) and immunohistochemical analysis using anti-POMC antibody. Results: No morphological differences were seen in all the group samples stained with H&E. POMC expression of the urothelium of bladder tissue samples shows different staining levels. Group 1 (96.7 +/- 7.68), Group 2 (88.3 +/- 8.04), and Group 3 (85.10 +/- 10.9) were very weakly stained, but the POMC immunoreactivity of Group 4 (113.0 +/- 12.8) was observed to be strong. Conclusion: Expression of POMC from urothelium seems to prevent bladder damage from radiation supplying differentiation and restoration of the urothelium.
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    Influence of Radiation Exposure During Radiotherapy Evidence for the Increase of Versican and Heparin-Binding EGF-like Growth Factor Concentrations
    Ozbilgin, MK; Aktas, C; Uluer, ET; Buyukuysal, MC; Gareveran, MS; Kurtman, C
    OBJECTIVE: To investigate the reaction of versican and heparin-binding EGF-like growth factor (HB-EGF) molecule concentrations to acute radiation exposure in normal bladder and rectal tissue samples in order to gain more insight into the effects of cancer radiotherapy. STUDY DESIGN: Four groups with 6 male adult Swiss Albino mice per group were investigated. The mice bladder and rectum tissue samples were subjected to a 10-Gy single-dose radiation exposure in the pelvic region with a Co-60 teletherapy device and investigated 1, 2, and 7 days after radiation exposure, with 1 reference group which was not exposed to radiation. RESULTS: In the immunohistochemical examination of the tissue samples with anti-versican and anti-HB-EGF primary antibodies was observed a statistically significant increase 7 days after radiation exposure. CONCLUSION: The observed increase of versican and HB-EGF concentrations in the normal tissue matrix after radiation exposure may play a role in the side effects of radiotherapy.
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    Effects of Cyclooxygenase on the Urothelium of the Urinary Bladder of Mice Exposed to Pelvic Radiation
    Ozbilgin, MK; Onal, T; Ozcan, C; Temel, E; Aktas, C; Gareveran, MS; Uluer, ET; Limn, S; Kurtman, C
    Objective: To determine the role of cyclooxygenase (COX) expression in the urothelium of the urinary bladder during radiation injury caused by pelvic radiotherapy for cancer therapy. Study Design: Twenty-four male Swiss Albino mice were separated into 4 groups. The first group was the control group (Group 1) and the second, third, and fourth groups were euthanized after 24 hours (Group 2), 48 hours (Group 3), and 7 days (Group 4), respectively. A single-fractioned 10 Gy of ionizing radiation was applied to all mices pelvic zone with Co-60. Bladders were removed completely from the pelvic region. Histochemical analysis using hematoxylin and eosin and immunohistochemical analysis using anti-COX-1 and COX-2 antibodies were performed on tissue samples. The immunoreactivities of the urinary bladder were quantified using H-score measurement, and statistical comparison was performed. Results: In the immunohistochemical examination the COX-1 immunoreactivities were found to be higher in the urothelium of the bladder in the radiation exposed groups than in the normal control group (group 1) (p<0.005). Additionally, high immunoreactivity of COX-2 molecule was established in groups 2, 3, and 4 of radiation groups as compared to group 1 (p<0.005) in examination of the urothelium. COX-1 and COX-2 immunoreactivities in the submucosa were detected higher in group 4 than in the other groups (p<0.005). Conclusion: COX-1 and COX-2 expressions in the urothelium and subepithelium of the urinary bladder were investigated in mice during the acute radiation response. The expression of COX-1 and COX-2 in the urothelium seems to prevent bladder damage from radiation, supplying differentiation and restoration of the urothelium.
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    An Experimental Study of Radiation Effect on Normal Tissue: Analysis of HIF-1α, VEGF, eIF2, TIA-1, and TSP-1 Expression
    Aktas, C; Kurtman, C; Özbilgin, MK; Tek, I; Toprak, SK
    Objective: This study investigated whether or not the stress and hypoxia, which are the effects of radiation on normal vascular endothelium, leading to the release of HIF-1 alpha, VEGF, eIF2, TIA-1, and TSP-1 were related and the possibility of them stimulating angiogenesis. Materials and Methods: Twenty-four male Swiss Albino mice were separated into 4 groups. The first group was the control group (Group 1), and the second, third, and fourth groups were euthanized after 24 h (Group 2), 48 h (Group 3), and 7 days (Group 4), respectively. A single-fractioned 10 Gy of ionizing radiation was applied to all mice's pelvic zone with Co-60. Bladders were removed completely from the pelvic region. Immunohistochemistry and light microscopy were used to investigate whether there would be an increase or not in the angiogenesis pathway by using the HIF-1 alpha, VEGF, eIF2, TIA-1, and TSP-1 antibodies. Results: The HIP-1 alpha antibody showed strong staining in Group 3, while the staining intensity was less in other groups. VEGF showed weak staining in Groups 1 and 4, while moderate staining in Group 2 and strong staining in Group 3 was observed. eIF2 showed strong staining in Groups 1 and 4. Groups 2 and 3 were stained weakly. In the present study, staining with TSP-1 was very strong in the samples belonging to Group 1, while other groups showed very weak staining. Conclusion: When normal tissue was exposed to radiation, the positively effective factors (HIF-1, VEGF, eIF2, and TIA-1) on the angiogenesis pathway were increased while the negative factor (TSP-1) was decreased. Radiation may initiate physiological angiogenesis in the normal tissue and accelerate healing in the damaged normal tissue.