Person: ATASOY, BESTE MELEK
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ATASOY
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BESTE MELEK
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Publication Open Access Propylthiouracil-induced hypothyroidism protects ionizing radiation-induced multiple organ damage in rats(BIOSCIENTIFICA LTD, 2006-05) VELİOĞLU ÖĞÜNÇ, AYLİZ; Sener, G.; Kabasakal, L.; Atasoy, B. M.; Erzik, C.; Velioglu-Ogunc, A.; Cetinel, S.; Contuk, G.; Gedik, N.; Yegen, B. C.The objective of this study was to examine the potential radioprotective properties of propylthiouracil (PTU)-induced hypothyroidism against oxidative organ damage induced by irradiation. Sprague-Dawley rats were pre-treated with saline or PTU (10 mg/kg i.p.) for 15 days, and were then exposed to whole-body irradiation (800 cGy). A group of rats were decapitated at 6 h after exposure to irradiation, while another group was followed for 72 h after irradiation, during which saline or PTU injections were repeated once daily. Lung, liver, kidney and ileum samples were obtained for the determination of malondialdehyde (MDA; an index of lipid peroxidation) and glutathione (GSH, an antioxidant) levels, myeloperoxidase activity (MPO; an index of tissue neutrophil accumulation) and collagen contents, while oxidant-induced DNA fragmentation was evaluated in the ileal tissues. All tissues were also examined microscopically and assayed for the production of reactive oxidants using chemiluminescence (CL). Lactate dehydrogenase (LDH), an indicator of tissue damage, and turnout necrosis factor-alpha (TNF alpha) were assayed in serum samples. Irradiation caused a significant decrease in GSH level, which was accompanied by significant increases in MDA levels, MPO activity, CL levels and collagen content of the tissues studied (P < 0.05-0.001). Similarly, serum TNFa and LDH were elevated in the irradiated rats as compared with the control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by irradiation. Our results suggested that PTU-induced hypothyroidism reduces oxidative damage in the lung, hepatic, renal and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.Publication Open Access Treatment results and prognostic factors in primary thyroid lymphoma patients: a Rare Cancer Network study(OXFORD UNIV PRESS, 2011-01) ATASOY, BESTE MELEK; Onal, C.; Li, Y. X.; Miller, R. C.; Poortmans, P.; Constantinou, N.; Weber, D. C.; Atasoy, B. M.; Igdem, S.; Ozsahin, M.; Ozyar, E.Background: This study analyzed prognostic factors and treatment outcomes of primary thyroid lymphoma. Patients and Methods: Data were retrospectively collected for 87 patients (53 stage I and 34 stage II) with median age 65 years. Fifty-two patients were treated with single modality (31 with chemotherapy alone and 21 with radiotherapy alone) and 35 with combined modality treatment. Median follow-up was 51 months. Results: Sixty patients had aggressive lymphoma and 27 had indolent lymphoma. The 5- and 10-year overall survival (OS) rates were 74% and 71%, respectively, and the disease-free survival (DFS) rates were 68% and 64%. Univariate analysis revealed that age, tumor size, stage, lymph node involvement, B symptoms, and treatment modality were prognostic factors for OS, DFS, and local control (LC). Patients with thyroiditis had significantly better LC rates. In multivariate analysis, OS was influenced by age, B symptoms, lymph node involvement, and tumor size, whereas DFS and LC were influenced by B symptoms and tumor size. Compared with single modality treatment, patients treated with combined modality had better 5-year OS, DFS, and LC. Conclusions: Combined modality leads to an excellent prognosis for patients with aggressive lymphoma but does not improve OS and LC in patients with indolent lymphoma.Publication Open Access Clinical Outcomes of Rectal Squamous Cell Carcinomas Treated with Chemoradiotherapy with or Without Surgery: A Rare Cancer Network Study.(ELSEVIER SCIENCE INC, 2018-11) ATASOY, BESTE MELEK; De Bari, B.; Aloi, D.; Lemanski, C.; Hallemeier, C. L.; Touboul, E.; Qi, S.; Christie, D.; Vees, H.; Shulman, K.; Atasoy, B. M.; Sefik, I.; Micke, O.; Vernat, S. Servagi; Khanfir, K.Publication Open Access Effects of resveratrol against scattered radiation-induced testicular damage in rats(WALTER DE GRUYTER GMBH, 2021-09-06) ATASOY, BESTE MELEK; Sener, Tarik Emre; Atasoy, Beste Melek; Cevik, Ozge; Kaya, Ozlem Tugce Cilingir; Cetinel, Sule; Degerli, Ayse Dagli; Sener, GokselObjectives: To investigate the possible protective effects of resveratrol against oxidative testicular damage due to scattered radiation during pelvic ionizing radiation exposure in rats. Methods: Rats were divided into 5 groups; control, radiation, and radiation + resveratrol therapy in early and late periods. Under anesthesia, 20 Gy ionizing radiation was applied to prostatic region. Resveratrol was administered (10 mg/kg/day) orally before ionizing radiation exposure. Animals were decapitated at the end of 1st and 10th weeks. Biochemical markers of oxidative stress; caspase-3 and sirtuin-1 protein expressions; testosterone levels were evaluated, histological examinations were performed. Results: Significant increases in malondialdehyde, 8-hydroxy-deoxyguanosine levels, myeloperoxidase, and caspase-3 activities were observed after ionizing radiation exposure, also superoxide dismutase and glutathione activities were significantly decreased. Radiotherapy increased caspase-3 and decreased sirtuin-1 protein expressions. Resveratrol treatment significantly reversed these parameters and also reversed the decrease in testosterone levels back to control levels in late period. Conclusion: Resveratrol showed antioxidant and sirtuin-activating properties against oxidative damage caused by scattered radiation to testis and provided hormonal protection. These results suggest that resveratrol may be an alternative protective agent on testicular tissues against the effects of scattered pelvic radiation.Publication Open Access Radiation-induced oxidative injury of the ileum and colon is alleviated by glucagon-like peptide-1 and -2(ELSEVIER SCIENCE BV, 2015-04) ATASOY, BESTE MELEK; Deniz, Mustafa; Atasoy, Beste M.; Dane, Faysal; Can, Guray; Erzik, Can; Cetinel, Sule; Yegen, Berrak C.Purpose: The present study was conducted to characterize the possible therapeutic effects of glucagon-like peptide (GLP)-1 and GLP-2 against oxidative damage in the ileum and colon of irradiated rats. Methods and materials: Sprague-Dawley rats of both sexes received either a single dose of GLP-1 (0.1 nmol/kg, intraperitoneally, ip; n = 6) 10 min before abdominal irradiation (IR) or two consecutive doses of GLP-2 (7 nmol/kg, ip; n = 6) at 30 and 10 min before IR, while another group was administered vehicle (n = 6) 10 min before IR. Control rats (n = 6) received vehicle treatment without IR. On the fourth day of IR, samples from ileum and colon were removed for histological analysis, for the determination of myeloperoxidase (MPO) activity, malondialdehyde (MDA) and glutathione (GSH) levels, as well as DNA fragmentation ratio, an index of apoptosis. Results: IR-induced oxidative injury in the colonic tissue of vehicle-treated rats, evidenced by elevated MDA levels and MPO activity, as well as depleted colonic GSH levels, was reversed by GLP-2, while GLP-1 reduced IR-induced elevations in colonic MDA levels. IR-induced injury with elevated ileal MDA levels was reduced by GLP-1, while replenishment in GSH was observed in GLP-2-treated rats. Conclusion: Current findings suggest that GLP-1 and GLP-2 appear to have protective roles in the irradiation-induced oxidative damage of the gut by inhibiting neutrophil infiltration and subsequent activation of inflammatory mediators that induce lipid peroxidation. Copyright (C) 2015, The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license.Publication Open Access Functional and clinical evaluation of renal injury in patients treated with adjuvant chemoradiotherapy for gastric cancer: Low dose and comorbidity considerations(ELSEVIER SCIENCE BV, 2016-01) ATASOY, BESTE MELEK; Ibrahimov, Roman; Atasoy, Beste M.; Dede, Fuat; Arikan, Hakki; Ozen, Zeynep; Ozgen, Zerrin; Dane, Faysal; Abacioglu, UfukAim: To analyze the dosimetric factors affecting long-term renal function in patients with gastric cancer following postoperative radiotherapy with concomitant chemotherapy to the upper abdomen. Methods: Between January 2005 and July 2010, 13 patients treated with three-dimensional conformal radiotherapy and concurrent fluorouracil-based chemotherapy (CRT) were included in this analysis. After a median follow-up of 55 months, creatinine, glomerular filtration rate (GFR), total kidney and left kidney volumes, before and after CRT and mercaptoacetyltriglycine (MAG3) scintigraphy, were used to evaluate the renal function and were correlated with the dosimetrics data. Results: Significant correlations were found in the loss of left kidney volume and V35 (20.6%) (p = 0.035) and V40 (15.7%) (p = 0.031) and in the loss of relative functional contribution of the main kidney and V35 Gy (p = 0.027) and V40 Gy (p = 0.019). In patients with a slightly low basal GFR (n = 6), the relative functional contribution of the left kidney significantly decreased, regardless of the dosage. Conclusion: Functional renal impairment without any clinical signs or symptoms can be observed in low doses after radiotherapy. Careful treatment planning and a detailed evaluation of the functional renal capacity before treatment may help to reduce late renal toxicity. Copyright (C) 2015, The Egyptian Society of Radiation Sciences and Applications. Production and hosting by Elsevier B.V.Publication Open Access Long-term effects of neoadjuvant chemoradiotherapy followed by sphincter-preserving resection on anal sphincter function in relation to quality of life among locally advanced rectal cancer patients: a cross-sectional analysis(BMC, 2015-12) ATASOY, BESTE MELEK; Ozgen, Zerrin; Ozden, Sevgi; Atasoy, Beste M.; Ozyurt, Hazan; Gencosmanoglu, Rasim; Imeryuz, NeseBackground: There is growing recognition for the consequences of rectal cancer treatment to maintain an adequate functional sphincter in the long-term rather than preserving the anal sphincter itself. This study aims to evaluate long-term effects of neoadjuvant chemoradiotherapy (nCRT) followed by sphincter-preserving resection on anal sphincter function in relation to quality of life (QoL) among locally advanced rectal cancer patients. Methods: Twenty-nine patients treated with nCRT followed by low anterior resection surgery were included in this study. Data on patient demographics, tumor location and symptoms of urgency and fecal soiling were recorded and evaluated with respect to Wexner Fecal Incontinence Scoring Scale, European Organization for Research and Cancer (EORTC) cancer-specific (EORTC QLQ-C30) and colorectal cancer-specific (EORTC QLQ-CR38) questionnaires and anorectal manometrical findings. Correlation of manometrical findings with Wexner Scale, EORTC QLQ-CR38 scores and EORTC QLQ-C30 scores was also evaluated. Results: Median follow-up was 45.6 months (ranged 7.5-98 months. Higher scores for incontinence for gas (p = 0.001), liquid (p = 0.048) and solid (p = 0.019) stool, need to wear pad (p = 0.001) and alteration in life style (p = 0.004) in Wexner scale, while lower scores for future perspective (p = 0.010) and higher scores for defecation problems (p = 0.001) in EORTC QLQ-CR38 were noted in patients with than without urgency. Manometrical findings of resting pressure (mmHg) was positively correlated with body image (r = 0.435, p = 0.030) and sexual functioning (r = 0.479, p = 0.011) items of functional scale, while rectal sensory threshold (RST) volume (mL) was positively correlated with defecation problems (r = 0.424, p = 0.031) items of symptom scale in EORTC QLQ-CR38 and negatively correlated with social function domain (r = -0.479, p = 0.024) in EORTC QLQ-C30. RST volume was also positively correlated with Wexner scores including incontinence for liquid stool (r = 0.459, p = 0.024), need to wear pad (r = 0.466, p = 0.022) and alteration in lifestyle (r = 0.425, p = 0.038). Conclusion: The high risk of developing functional anal impairment as well as the systematic registration of not only oncological but also functional and QoL related outcomes seem important in rectal cancer patients in the long-term disease follow-up.Publication Open Access Long-term outcomes of gamma-knife radiosurgery for intracanalicular vestibular schwannomas(2022-01-01) PINAR, ERTUĞRUL; BAYRİ, YAŞAR; BAYRAKLI, FATİH; SAKAR, MUSTAFA; ATASOY, BESTE MELEK; Sakar M., Pınar E., Bayri Y., Bayraklı F., Atasoy B. M., Ziyal M. İ.GİRİŞ ve AMAÇ: Kanal içi vestibüler schwannomalar, tüm vestibüler schwannomalar içerisinde küçük bir yüzdeye sahiptir. Kanal içi vestibüler schwannomalarda işitmenin korunması, hasta yönetiminin temel amaçlarındandır. Bu çalışmanın amacı, kanal içi vestibüler schwannomalarda Gamma-Knife radyocerrahinin (GKR) tümör kontrolü ve işitmenin korunması üzerine etkisinin incelenemesidir.YÖNTEM ve GEREÇLER: Bu geriye dönük çalışmada, Gamma-Knife Radyocerrahi Merkezi’mizde Ocak 2010–Ocak 2020 arasında kanal içi vestibüler schwannoma tanısı ile stereotaksik radyocerrahi almış, klinik, odyometrik ve radyolojik takibi bulunan hastalar değerlendirildi. Tümör kontrolü manyetik rezonans görüntüleme yönteminde tümör boyutlarının ölçülmesi ile takip edildi. İşitme seviyeleri Gardner-Robertson (GR) işitme sınıflaması yöntemine göre değerlendirildi.BULGULAR: Ortalama 48.23 aylık takipte, çalışmaya dahil edilen toplam 45 hastadan 44’ünde tümör kontrolü sağlandığı görüldü (%97.7). Tümör büyümesi görülen bir hastada ise, ek bir tedavi uygulanması gerekmedi. Ek tedavi gerekliliğine göre değerlendirildiğinde tüm hastalarda tümör kontrolü sağlandı (%100). Tedavi öncesi fonksiyonel işitmesi olan (GR derece I ve II) toplam 29 hastadan, ortalama 70.42 aylık takip sonrasında, toplam 13 hastada fonksiyonel işitme korundu (%44.8). GR derecesinde kayıp, ameliyat öncesinde yüksek GR derecesine sahip olmak ile korelasyon gösterdi (Rs=0.459, p=0.002). Tedavi dozu işitme kaybı ile korelasyona sahipti ve daha yüksek doz alan hastalar daha kötü sonuçlara sahipti (Rs=0.459, p=0.002).TARTIŞMA ve SONUÇ: Kanal içi vestibüler schwannomalarda GKR uzun dönemli takiplerde mükemmel tümör kontrolü sağlamaktadır. Beş yılın üzerindeki takip sürelerinde fonksiyonel işitmenin korunma oranı azalabilir. Kanal içi vestibüler schwannomalarda GKR sonrası işitmenin seyrini ortaya koyabilmek için uzun takip süreli daha fazla çalışma gerekmektedir.Anahtar Kelimeler:Gamma-knife radyocerrahi, işitmenin korunması; kanal içi; tümör kontrolü; vestibüler schwannoma.Publication Open Access Mucositis-Induced Pain due to Barrier Dysfunction may have a Direct Effect on Nutritional Status and Quality of Life in Head and Neck Cancer Patients Receiving Radiotherapy(KARE PUBL, 2020) ATASOY, BESTE MELEK; Atasoy, Beste M.; Kayhan, Kivanc Bektas; Demirel, Birsen; Akdeniz, EsraOBJECTIVE To maintain the barrier function against mucositis-induced pain and to improve the nutritional status and quality of life in head and neck cancer patients during radiotherapy. METHODS All patients (n=30) used oral gel to reduce mucositis-induced pain. Patients were examined weekly for the severity of mucositis, pain and nutritional status. The quality of life parameters was measured at the beginning and at the end of treatment. There was no restriction for pain killers against mucositis. RESULTS The only significant factor affecting the severity and frequency of mucositis was the cumulative radiation dose (p<0.001). Despite the regular use of oral gel, weight loss was observed in 65% of the patients. There was no difference concerning the severity of mucositis, cumulative radiation doses, or mean dose of oral mucosa between patients with no risk or at risk, according to SGA. However, self-assessment pain scores were significantly better in the well-nourished group (p=0.05 vs. 0.015) with better scores for dry mouth (p=0.043), social eating (p=0.006), swallowing difficulties (p=0.001) and communication (p=0.049). CONCLUSION Supporting the barrier function alone does not help to reduce the severity and frequency of mucositis, nor the oral pain in high doses. Mucositis-induced pain may have a direct effect on malnutrition risk and quality of life in head and neck cancer patients. Powerful strategies are required to manage pain due to mucositis during curative radiotherapy.Publication Open Access Neuroprotective effect of Myrtus communis against ionizing radiation-induced brain injury: Insights from histopathological and biochemical analysis in rats: TROD-GROG 005(2024-12-01) ATASOY, BESTE MELEK; Atasoy B. M.Aim: To investigate the potential radioprotective effects of Myrtus communis on brain tissue. Methods: Thirty female rats were divided into four groups. The control group (C) was applied with oral saline solution (SF) for four days. Myrtus communis (MC) groups started to receive MC (100 mg/kg, oral) either four days before (R + preMC) or immediately after (R + MC) irradiation for four days. Irradiation was applied 10 Gy in a single fraction. All rats were sacrificed on the fourth day of irradiation. Malondialdehyde (MDA), nitric oxide (NO), and glutathione (GSH) levels, myeloperoxidase (MPO), superoxide dismutase (SOD), and tissue factor activities (TFa) were determined for biochemical analysis. Hematoxylin&Eosin staining was done for histopathological analyses, and electrophoretic analyses were performed. Results: NO, MDA, and MPO levels were higher in all irradiated groups compared with the C group. MC administration decreased NO, MDA, and MPO levels in R + preMC and R + MC groups. MC administration increased GSH levels. TFa activity decreased in R groups but did not change with MC administration compared to the C group. Radiation-induced brain tissue injury decreased, and morphologically normal neurons were observed in both MC-added groups. Conclusion: Myrtus communis has a potential neuroprotective effect on brain tissue, attributed to its antioxidative, anti-inflammatory, and anti-lipid peroxidative properties.