Publications by authors named "Cenk Umay"

8 Publications

  • Page 1 of 1

Ultrastructural investigation of synaptic alterations in the rat hippocampus after irradiation and hyperthermia.

Ultrastruct Pathol 2020 Nov 30;44(4-6):372-378. Epub 2020 Oct 30.

Department of Histology and Embryology, School of Medicine, Marmara University , Istanbul, Turkey.

This study aimed to investigate ultrastructural synaptic alterations in rat hippocampus after in utero exposure to irradiation (IR) and postnatal exposure to hyperthermia (HT). There were four groups in each of the time points (3 and 6 months). IR group: Pregnant rats were exposed to radiation on the 17 gestational day. HT group: Hyperthermia was applied to the rat pups on the 10th day after their birth. IR+HT group: Both IR and HT were applied at the same time periods. Control group: No IR or HT was applied. Rat pups were sacrificed after 3 and 6 months. Thin sections from the dentate gyrus (DG) and the CA3 of hippocampus were evaluated for synapse numbers by electron microscopy. Synapses were counted, and statistical analysis was performed. Abnormalities in myelin sheath, mossy terminals and neuropil were observed in the CA3 and DG of all groups. The synapses in the CA3 region were significantly increased in the IR-3 month, IR-6 month, and IR+HT-3 month groups vs control group. Synapses were significantly increased in the DG of HT-3 month group. A trend for an increase in synapse numbers was seen in the CA3 and DG. Increased number of synapses in the rat hippocampus may be due to mossy fiber sprouting, possibly caused by in utero irradiation and/or postnatal hyperthermia.
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November 2020

Outcome of Early-Stage Glottic Laryngeal Carcinoma Patients Treated with Radical Radiotherapy Using Different Techniques.

J Oncol 2019 6;2019:8640549. Epub 2019 Nov 6.

Department of Radiation Oncology, Dokuz Eylul University Faculty of Medicine, Izmir, Turkey.

Purpose: The aim was to evaluate the treatment outcomes and prognostic characteristics of patients with early-stage glottic laryngeal carcinoma who underwent radical radiotherapy (RT) with different techniques.

Patients And Methods: Radiotherapy was applied using the 2D conventional technique between 1991 and 2004 (130 patients), 3DCRT until 2014 (125 patients), and by VMAT until January 2017 (44 patients). Clinical T stages were 38 (12.7%) for Tis, 209 (69.9%) for T1, and 52 (17.4%) for T2. Radiotherapy technique and energy, anterior commissure involvement, and stage were analyzed as prognostic factors.

Results: The median total dose was 66 (50-70) Gy, and median follow-up time was 72 (3-288) months; 5-year disease-specific survival (DSS) rates were 95.8%, 95.5%, and 88.6%, respectively, in Tis, T1, and T2 stages. In multivariate analyses, anterior commissure involvement was found significant for all survival and local control rates. The patients treated with VMAT technique had better local control and DSS rates. However, these results were not statistically significant.

Conclusion: In early-stage laryngeal carcinomas, radical RT is a function sparing and effective treatment modality, regardless of treatment techniques.
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November 2019

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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February 2019

The prognostic value of morphologic findings for lung squamous cell carcinoma patients.

Pathol Res Pract 2016 Jan 31;212(1):1-9. Epub 2015 Oct 31.

Department of Pathology, Dokuz Eylül University, Faculty of Medicine, Izmir, Turkey. Electronic address:

Background: Novel histopathological prognostic features for squamous cell carcinoma (SCC) of lung, such as tumor budding, mitotic rate, tumor stroma ratio, stroma type, stromal inflammation and necrosis, have been evaluated in the literature. In this study, the prognostic value of multiple morphological features is assessed in lung SCC.

Materials And Methods: This study reports on seventy-six patients with lung SCC treated with complete surgical excision. Tumor size, tumor stage, lymph node status, lymphovascular invasion, histopathologic grade, mitotic count, necrosis, tumor budding, tumor stroma ratio, stroma type, stromal lymphoplasmacytic reaction and ratios of stromal plasma cells and their relationship with the prognosis were evaluated. Univariate and multivariate analyses were performed for histopathological markers for local disease free survival (LDFS), distant disease free survival (DDFS), overall disease free survival (ODFS) and overall survival (OS).

Results: The univariate prognostic analysis of the pathological factors revealed that the pathological stage (OS: p=0.001, DDFS: p=0.040), lymph node metastases (OS: p=0.013), mitotic index (OS: p=0.026), tumor necrosis (DDFS: p=0.013, ODFS: p=0.021) and tumor size (OS: p=0.002) had a prognostic significance. The multivariate analysis demonstrated that the pathological stage (OS: p=0.021), tumor size (OS: p=0.044), lymph node status (DDFS: p=0.019, ODFS; p=0.041) and necrosis (ODFS: p=0.048) were independent prognostic factors.

Conclusions: Although many histopathological factors have recently been proposed as important prognostic markers, we only found significant results for mitotic index and tumor necrosis, as well as the well known parameters such as tumor stage and lymph node status. To the best of our knowledge, this is the first study evaluating such a wide range of morphological prognostic factors in lung SCC.
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January 2016

The effects of enteral glutamine on radiotherapy induced dermatitis in breast cancer.

Clin Nutr 2016 Apr 26;35(2):436-439. Epub 2015 Mar 26.

9 Eylul University Medical School, Department of Radiation Oncology, İzmir, Turkey.

Purpose: Radiotherapy is a critical component of breast cancer treatment. Many skin reactions ranging from erythema to moist desquamation and ulceration can be induced by high dose external beam radiotherapy. There is no golden standard for treating radiation dermatitis. Glutamine is an amino acid which improved wound healing through its anabolic effects and improvements in wound matrix formation in burn patients. We designed a study to show effects of glutamine in radiation induced dermatitis.

Material And Method: Forty patients who received radiotherapy for breast cancer were randomized into 2 groups. In group 1 the patients were treated with 15 gr of enteral glutamine whereas the patients in group 2 were treated with placebo. The radiation induced skin reactions were evaluated in both groups.

Results: In glutamine treated group 88, 9% of patients developed grade I toxicity comparing to 80% of patients in placebo group developed grade II toxicity. This difference between the groups was statistically significant. (p < 0.001) CONCLUSION: Enteral glutamine minimizes radiation induced dermatitis.
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April 2016

Distribution of Zonula Occludens-1 and Occludin and alterations of testicular morphology after in utero radiation and postnatal hyperthermia in rats.

Int J Exp Pathol 2012 Dec;93(6):438-49

Department of Histology and Embryology, School of Medicine, Marmara University, Istanbul, Turkey.

In utero irradiation (IR) and postnatal hyperthermia (HT) exposure cause infertility by decreasing spermatogenic colony growth and the number of sperm in rats. Four groups were used: (i) Control group, (ii) HT group (rats exposed to hyperthermia on the 10th postnatal day), (iii) IR group (rats exposed to IR on the 17th gestational day) and (iv) IR + HT group. Three and six months after the procedures testes were examined by light and electron microscopy. Some degenerated tubules in the HT group, many vacuoles in spermatogenic cells and degenerated tight junctions in the IR group, atrophic tubules and severe degeneration of tight junctions in the IR + HT group were observed. ZO-1 and occludin immunoreactivity were decreased and disorganized in the HT and IR groups and absent in the IR + HT group. The increase in the number of apoptotic cells was accompanied by a time-dependent decrease in haploid, diploid and tetraploid cells in all groups. Degenerative findings were severe after 6 months in all groups. The double-hit model may represent a Sertoli cell only model of infertility due to a decrease in spermatogenic cell and alterated blood-testis barrier proteins in rat.
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December 2012

Hippocampal neuronal damage in rats exposed to a double hit: irradiation and hyperthermia.

Turk Neurosurg 2011 ;21(4):454-60

Marmara University, Faculty of Medicine, Department of Histoogy and Embryology, Istanbul, Turkey.

Aim: In utero irradiation models induce diffuse neuronal damage. Experimental studies have shown that hyperthermia induced seizures are easily elicited and have high mortality accompanied by neuronal loss. Neuronal damage and loss are the results of cell death coupled with cortical development in altered cellular development. The aim of the study was to investigate the changes in hippocampus that was exposed to irradiation and hyperthermia.

Material And Methods: Four groups were studied: 1) The irradiation group was exposed to 225 cGy irradiation on the 17th gestational day; 2) The hyperthermia group was exposed to hyperthermia on the 10th postnatal day; 3) The hyperthermia plus irradiation group was exposed to in utero irradiation and postnatal hyperthermia; 4) The control group was sham operated. Animals were examined 3 and 6 months later.

Results: The hippocampus was atrophic with neuronal loss in CA regions and ectopic neurons were in irradiation group. Severe damage with the most atrophy was demonstrated in all regions of the irradiation plus hyperthermia group. In long term, damage was severe in all groups.

Conclusion: This study demonstrated more damage in hippocampi exposed to both irradiation and hyperthermia that may be taken as an evidence for the double hit hypothesis in the development of hippocampal damage.
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April 2012

The effects of tamoxifen on radiation-induced pulmonary fibrosis in Wistar albino rats: results of an experimental study.

Breast 2006 Jun 2;15(3):456-60. Epub 2005 Aug 2.

Department of Radiation Oncology, Cerrahpasa Medical School, Istanbul University, and Department of Pathology, GATA Haydarpasa Training Hospital, Istanbul, Turkey.

This study was performed to evaluate the effects of tamoxifen on pulmonary fibrosis, given concurrently with or after irradiation in Wistar albino rats. Twenty-one female Wistar albino rats were randomized into three groups. The first group (Group A) had tamoxifen, which was started after the completion of irradiation. The second group (Group B) had tamoxifen concomitant with irradiation. The third group (Group C) had only thoracic irradiation and did not receive tamoxifen. Whole lungs were irradiated to a total dose of 30Gy in ten fractions with Co60. Tamoxifen was continued until the animals were sacrificed 16 weeks after the start of irradiation. As an end point the percentage of lung with fibrosis for each rat was quantified with image analysis of histological sections of the lung. Groups were compared using the one-way ANOVA method and Bonferroni post hoc test. The mean percentage values of fibrosis were 10.03 for Group A, 36.81 for Group B, and 3.87 for group C (P<0.001). When the percentages of fibrosis were compared for each group, the difference was statistically significant between Group A and Group B (P<0.001) and between Group B and Group C (P<0.001). Concomitant use of tamoxifen appears to increase radiation-induced pulmonary fibrosis and it seems more convenient to delay tamoxifen until the completion of irradiation.
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June 2006