Publications by authors named "Nilsu Çini"

5 Publications

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CT Derived Hounsfield Unit: An Easy Way to Determine Osteoporosis and Radiation Related Fracture Risk in Irradiated Patients.

Front Oncol 2020 13;10:742. Epub 2020 May 13.

Department of Radiation Oncology, Kartal Dr. Lutfi Kirdar Education and Research Hospital, Istanbul, Turkey.

We aimed to evaluate osteoporosis, bone mineral density, and fracture risk in irradiated patients by computerized tomography derived Hounsfield Units (HUs) calculated from radiation treatment planning system. Fifty-seven patients operated for gastric adenocarcinoma who received adjuvant abdominal radiotherapy were included in the study group. Thirty-four patients who were not irradiated after surgery comprised the control group. HUs of T12, L1, L2 vertebral bodies were measured from the computerized tomographies imported to the treatment planning system for all the patients. While the measurements were obtained just after surgery and 1 year later after surgery in the control group, the same measurements were obtained just before irradiation and 1 year after radiotherapy in the study group. Percent change in HU values (Δ%HU) was determined for each group. Vertebral compression fractures, which are the consequence of radiation induced osteoporosis and bone toxicity were assessed during follow-up. There was no statistical significant difference in HU values measured for all the vertebrae between the study and the control group at the onset of the study. While HU values decreased significantly in the study group, there was no significant reduction in HU values in the control group after 1 year. significant correlation was found between Δ%HU and the radiation dose received by each vertebra. Insufficiency fractures (IFs) were observed only in the irradiated patients (4 out of 57 patients) with the cumulative incidence of 7%. HU values are very valuable in determining bone mineral density and fracture risk. Radiation treatment planning system can be utilized to determine HU values. IFs are common after abdominal radiotherapy in patients with low vertebral HU values detected during radiation treatment planning. Radiation dose to the vertebral bones with low HU values should be limited below 20 Gy to prevent late radiation related bone toxicity.
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http://dx.doi.org/10.3389/fonc.2020.00742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7237579PMC
May 2020

Modulation of radiation-induced oral mucositis (mouse) by dermatan sulfate: effects on differentiation processes.

Strahlenther Onkol 2020 Jan 8;196(1):85-94. Epub 2019 Nov 8.

Department Radiation Oncology/CD Lab. Med. Radiation Research for Radiation Oncology, Applied and Translational Radiobiology, Medical University/AKH Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.

Purpose: During head and neck cancer radiotherapy, oral mucositis is the most frequent early side effect. Systemic dermatan sulfate (DS) administration has been shown to significantly decrease oral mucosal radiation reactions during daily fractionated irradiation (IR) in an established mouse model. The aim of this study was to investigate the mechanism of the oral epithelial differentiation process, during IR alone and in combination with DS treatment in the same mouse model.

Methods: Fractionated IR 5 × 3 Gy/week was given to the snouts of mice over two weeks, either alone (IR) or in combination with daily DS treatment of 4 mg/kg (IR + DS). Groups of mice (n = 3) were sacrificed every second day over the course of 14 days in both experimental arms. Their tongue was excised and subjected to immunohistochemical processing.

Results: In the p16 analysis as a proliferation marker, the difference between IR alone and IR + DS in the germinal (proliferation) layer was not significant, not stimulating the proliferation process. For the p21 analysis as a differentiation marker on the functional (differentiation) layer, the difference between IR alone and IR + DS arms was significant, indicating that DS inhibited the differentiation process. In the cytokeratin (CK) analysis as the indicator of cellular skeletal integrity, the percentage of antibody-positive cells was above the normal level in both experimental arms and significantly superior in the IR + DS arm.

Conclusion: The mucosal protective activity of DS, instead of stimulating proliferation, is based on prevention of cell loss by a combination of effects leading to the inhibition of cellular differentiation and an increase in the expression of epithelial mechanical strength between intercellular mechanical junctions.
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http://dx.doi.org/10.1007/s00066-019-01532-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6957576PMC
January 2020

Dosimetric comparison of anterior posterior-posterior anterior 2-field three-dimensional conformal radiotherapy, 4-field three-dimensional conformal radiotherapy and "forward" plan intensity modulated radiotherapy techniques in female lymphoma patients irradiated to neck and mediastinum.

J Cancer Res Ther 2018 Oct-Dec;14(6):1389-1396

Department of Radiation Oncology, Dokuz Eylül University Medical Faculty, Izmir, Turkey.

Aim: Dosimetric comparison of three different techniques in female lymphoma patients who had radiotherapy (RT) to the neck and mediastinum.

Setting And Design: Retrospective clinical study.

Materials And Methods: Computerized tomography-simulator images of eight patients were obtained retrospectively. Using 6 MV-X photon energy, RT plans were formed with three different techniques (anterior posterior-posterior anterior 2-field three-dimensional conformal RT [AP-PA 2-field 3D-CRT], 4-field 3D-CRT and "forward" plan intensity modulated RT [FPIMRT]). Comparisons were in terms of homogeneity index (HI), conformity index (CI), and inhomogeneity coefficient for planning target volume (PTV); mean lung dose, V, V, V, V for lung; D, V, V, V for heart; D, V, V, V for breast; D for spine; D, V, V, V, V for thyroid.

Statistical Analysis Used: Since nonparametric tests had to be used due to the study population being < 30, Friedman and Wilcoxon signed-rank tests were implemented in trilateral and bilateral comparison of techniques, respectively. For statistical significance, P value was required to be <0.05.

Results: When FPIMRT was compared with AP-PA and 4-field techniques with respect to, HI (AP-PA/FPIMRT P: 0.017; 4-field/FPIMRT P: 0.03) and CI (AP-PA/FPIMRT P: 0.018; 4-field/FPIMRT P: 0.042), FPIMRT was more advantageous. In addition, FPIMRT was found more useful in terms of D (AP-PA/FPIMRT P: 0.012; 4-Field/FPIMRT P: 0.012) for spinal cord and D (AP-PA/FPIMRT P: 0.012; 4-field/FPIMRT P: 0.012) for thyroid.

Conclusion: FPIMRT was superior in terms of PTV homogeneity and conformity. However, it was observed that for normal tissues, FPIMRT was advantageous only for spinal cord and thyroid; but it was not the most advantageous technique for some of the dose-volume parameters of the breast, lung, and heart.
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http://dx.doi.org/10.4103/0973-1482.193108DOI Listing
February 2019

Radioprotective Effects of Dermatan Sulfate in a Preclinical Model of Oral Mucositis-Targeting Inflammation, Hypoxia and Junction Proteins without Stimulating Proliferation.

Int J Mol Sci 2018 06 6;19(6). Epub 2018 Jun 6.

Department of Radiation Oncology, Applied and Translational Radiobiology, Medical University Vienna, 1090 Vienna, Austria.

Oral mucositis is the most frequently occurring early side effect of head-and-neck cancer radiotherapy. Systemic dermatan sulfate (DS) treatment revealed a significant radioprotective potential in a preclinical model of oral mucositis. This study was initiated to elucidate the mechanistic effects of DS in the same model. Irradiation comprised daily fractionated irradiation (5 × 3 Gy/week) over two weeks, either alone (IR) or in combination with daily dermatan sulfate treatment of 4 mg/kg (IR + DS). Groups of mice ( = 5) were sacrificed every second day over the course of 14 days in both experimental arms, their tongues excised and evaluated. The response to irradiation with and without DS was analyzed on a morphological (cell numbers, epithelial thickness) as well as on a functional (proliferation and expression of inflammation, hypoxia and epithelial junction markers) level. The mucoprotective activity of DS can be attributed to a combination of various effects, comprising increased expression of epithelial junctions, reduced inflammation and reduced hypoxia. No DS-mediated effect on proliferation was observed. DS demonstrated a significant mucositis-ameliorating activity and could provide a promising strategy for mucositis treatment, based on targeting specific, radiation-induced, mucositis-associated signaling without stimulating proliferation.
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http://dx.doi.org/10.3390/ijms19061684DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6032103PMC
June 2018

Upregulated epithelial junction expression represents a novel parameter of the epithelial radiation response to fractionated irradiation in oral mucosa.

Strahlenther Onkol 2018 08 19;194(8):771-779. Epub 2018 Apr 19.

Dept. Radiation Oncology/CD Lab. Med. Radiation Research for Radiation Oncology, Applied and Translational Radiobiology, Medical University/AKH Vienna, Währinger Gürtel 18-20, 1090, Vienna, Austria.

Purpose: During head and neck cancer treatment, the radiation response of the oral mucosa represents a frequent early side effect. Besides radiation-induced inhibition of proliferation, various other cellular responses occur. The radiation response of adherens and tight junction proteins was so far mostly investigated with large single-dose irradiation protocols, in vivo and in vitro. Therefore, the current study was initiated to investigate the impact of daily fractionated irradiation on the expression of adherens and tight junction proteins in vivo.

Materials And Methods: Fractionation with 5 × 3 Gy/week (days 0-4, 7-11) was given to the snouts of mice. Groups of 5 animals per day were euthanized every second day between day 0 (unirradiated controls) and day 14, and their tongues subjected to histological processing. Adherens junction marker (β-catenin and E‑cadherin) and tight junction marker (claudin-1 and occludin) expression was analysed in the oral mucosa of unirradiated controls and during two weeks of fractionated irradiation.

Results: Adherens as well as tight junction marker proteins were rapidly and consistently upregulated in both the germinal as well as the functional layer of the oral mucosa. This represents a previously unknown parameter of the epithelial radiation response to clinically relevant fractionation protocols.

Conclusion: Fractionated irradiation significantly enhanced the expression of all proteins investigated. This study revealed a new parameter of the epithelial radiation response to fractionated irradiation.
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http://dx.doi.org/10.1007/s00066-018-1302-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6061151PMC
August 2018