Browsing by Author "Ozgun, Gonca"

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Anatomical Aspects of Optic Nerve Decompression in Transcranial and Transsphenoidal Approach
(2019) Guler, Tugba Morali; Yilmazlar, Selcuk; Ozgun, Gonca; 30837103
Purpose: The proximal portion of the optic nerve is quite prone to injury at the entrance of the optic foramen by tumoral or traumatic pathologies. As a result, it is important to show which way and which part we can effectively and safely decompress the pathologies affecting the optic nerves. In this study, we compared the decompression of the proximal segment of the optic canal Likewise, we investigated the anatomy and histopathology of the opticocarotid region from below and above. Materials and methods: A total of 30 adult sellar and parasellar samples were extracted from human cadavers. Anatomical dissection and histological examination were performed from transcranial and transsphenoidal ways. The walls of the proximal optic canal were evaluated with an operating microscope and endoscope. The relationship between the optic canal, the internal carotid artery, and the optic nerve were qualitatively and quantitatively examined. Results: Similar rates of circular optic canal decompression were achieved by each approach; however, by means of decompression, the transsphenoidal approach was superior for the inferior and medial portions of the optic nerve and transcranial approach was superior for the superior and lateral portions and also more appropriate for optic nerve mobilization. Conclusion: This is one of the first studies to reveal the ways of the decompression of the proximal optic canal by transcranial and transsphenoidal approaches. According to this study, the medial and inferior proximal portions of the optic nerves are histologically more prone to injury caused by traction or compression. Transcranial or transsphenoidal approach should be preferred according to the location of the pathology and anatomical and histological characteristics of this region. (C) 2019 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.
Baskent University Expanded Criteria for Hepatocellular Carcinoma: The Importance of the Histopathological Features as a Part of the Evaluation Criteria for Liver Transplantation
(2018) Ozgun, Gonca; Ozdemir, B. Handan; Moray, Gokhan; Reyhan, Nihan Haberal; Akdur, Aydincan; Kirnap, Mahir; Haberal, Mehmet; https://orcid.org/0000-0002-7528-3557; https://orcid.org/0000-0003-2498-7287; https://orcid.org/0000-0001-9852-9911; https://orcid.org/0000-0002-8726-3369; https://orcid.org/0000-0002-3462-7632; X-8540-2019; AAE-1041-2021; AAK-4587-2021; AAA-3068-2021; AAH-9198-2019; AAJ-8097-2021
Baskent University Expanded Criteria for Hepatocellular Carcinoma: The Importance of the Histopathological Features as a Part of the Evaluation Criteria for Liver Transplantation
(2018) Ozgun, Gonca; Ozdemir, B. Handan; Moray, Gokhan; Reyhan, Nihan Haberal; Akdur, Aydincan; Kirnap, Mahir; Haberal, Mehmet; 0000-0002-7528-3557; 0000-0003-2498-7287; 0000-0001-9852-9911; 0000-0002-8726-3369; 0000-0002-3462-7632; X-8540-2019; AAE-1041-2021; AAK-4587-2021; AAA-3068-2021; AAH-9198-2019; AAJ-8097-2021
Clinical Findings and Explant Liver Histology in Crigler Najjar Disease
(2018) Baris, Zeren; Ozgun, Gonca; Sezer, Oya Balci; Haberal, Mehmet; 0000-0002-8402-8208; 0000-0002-3462-7632; AAB-4153-2020; AAI-9346-2021; AAJ-8097-2021
Colon Biopsy Findings of Renal Transplant Patients
(2016) Tastepe, Firdevs Zeynep; Ozgun, Gonca; Ozdemir, Binnaz Handan; Tepeoglu, Merih; Haberal, Mehmet; 0000-0002-3462-7632; 0000-0002-9894-8005; 0000-0002-3462-7632; 27805519; AAJ-8097-2021; AAK-5222-2021; AAJ-8097-2021
Objectives: The purpose of this study was to evaluate colonic pathologies in renal transplant recipients. Materials and Methods: Patients with colon biopsies were selected from 1816 renal transplant recipients from January 1990 to December 2012 at Baskent University Hospital (Ankara, Turkey). Demographic and clinical findings with colon biopsies were examined. Results: There were 84 patients who had colon biopsies after renal transplant. There were 57 male and 27 female patients (median age at renal transplant was 33 y). Chronic diarrhea was the most common clinical finding at the time of colon biopsy. The median interval from renal transplant to first colon biopsy was 48.1 +/- 47.5 months. On microscopic evaluation, there were no pathologic changes in 17 patients. The remaining 67 patients had colitis (38 patients), polyps (17 patients), cytomegalovirus colitis (8 patients), and amyloidosis (4 patients). The mean interval between transplant and the diagnosis of colitis was 49.08 +/- 42.6 months, amyloidosis was 47.5 +/- 79.28 months, cytomegalovirus colitis was 5 +/- 3.5 months, and polyps was 77.65 +/- 58.8 months. There was a statistically significant difference between biopsy diagnosis and the time interval between transplant and colon biopsy (P <.01). Among 84 renal transplant recipients with colonic biopsies, 40 patients never had acute rejection episodes and 44 patients had at least 1 acute rejection episode. Seven of 8 patients with cytomegalovirus colitis, 19 of 38 with colitis, 3 of 4 with amyloidosis, and 5 of 17 with polyps had acute rejection episodes. Conclusions: In our report on colonic manifestations in renal transplant recipients, the most common colonic lesion was noninfectious colitis. Cytomegalovirus colitis is an important infection that affects immuno-suppressed individuals, such as transplant recipients. Cytomegalovirus must be kept in mind, and thorough sectioning and immunohistochemical staining should be used if necessary in the presence of any clinical or histologic suspicion for infective colitis.
COVID-19 Pandemic Impact On Cytopathology Practice In The Post-Lockdown Period: An International, Multicenter Study
(2022) Ozgun, Gonca; 35006650
Background In a previous worldwide survey, the authors showed a drastic reduction in the number of cytological specimens processed during the coronavirus disease 2019 "lockdown" period along with an increase in malignancy rates. To assess the continued impact of the pandemic on cytological practices around the world, they undertook a second follow-up worldwide survey collecting data from the post-lockdown period (2020). Methods Participants were asked to provide data regarding their cytopathology activity during the first 12 weeks of their respective national post-lockdown period (2020), which ranged from April 4 to October 31. Differences between the post-lockdown period and the corresponding 2019 period were evaluated, and the authors specifically focused on rates of malignant diagnoses. Results A total of 29 respondents from 17 countries worldwide joined the survey. Overall, a lower number of cytological specimens (n = 236,352) were processed in comparison with the same period in 2019 (n = 321,466) for a relative reduction of 26.5%. The overall malignancy rate showed a statistically significant increase (12,442 [5.26%] vs 12,882 [4.01%]; P < .001) during the same time period. Similar results were obtained if both malignancy and suspicious for malignancy rates were considered together (15,759 [6.58%] vs 16,011 [4.98%]; P < .001). Conclusions The data showed a persistent reduction in the cytological specimen volume during the post-lockdown period (2020). However, the relative increase in the cytological workload in the late part of the post-lockdown is a promising finding of a slow return to normality.
CYTOMEGALOVIRUS (CMV) INFECTION INDUCES AN ANGIOGENIC RESPONSE THROUGH HEPATIC STELLATE CELLS (HSCS) AND LEADS TO EARLY POST-TRANSPLANT LIVER FIBROSIS (LF) AND POOR GRAFT SURVIVAL
(2019) Ozdemir, B. Handan; Ozgun, Gonca; Soy, Ebru H. Ayvazoglu; Haberal, Nihan; Moray, Gokhan; Haberal, Mehmet; 0000-0002-0993-9917; AAC-5566-2019
Cytomegalovirus Infection Induces an Angiogenic Response through Hepatic Stellate Cells and Leads to Early Post-Transplant Liver Fibrosis and Poor Graft Survival
(2019) Ozdemir, B. Handan; Ozgun, Gonca; Soy, Ebru H. Ayvazoglu; Haberal, Nihan; Moray, Gokhan; Haberal, Mehmet A.
The Effect of Adipose Derived Stromal Vascular Fraction on Stasis Zone in An Experimental Burn Model
(2018) Eyuboglu, Atilla Adnan; Uysal, Cagri A.; Ozgun, Gonca; Coskun, Erhan; Ertas, Nilgun Markal; Haberal, Mehmet; 0000-0002-3462-7632; 0000-0001-6236-0050; 0000-0002-9805-9830; 29032969; AAJ-8097-2021; AAJ-2949-2021; IQW-7940-2023
Background: Stasis zone is the surrounding area of the coagulation zone which is an important part determining the extent of the necrosis in burn patients. In our study we aim to salvage the stasis zone by injecting adipose derived stromal vascular fraction (ADSVF). Methods: Thermal injury was applied on dorsum of Sprague-Dawley rats (n=20) by the "comb burn" model as described previously. When the burn injury was established on Sprague-Dawley rats (30min); rat dorsum was separated into 2 equal parts consisting of 4 burn zones (3 stasis zone) on each pair. ADSVF cells harvested from inguinal fat pads of Sprague-Dawley rats (n=5) were injected on the right side while same amount of phosphate buffered saline (PBS) injected on the left side of the same animal. One week later, average vital tissue on the statis zone was determined by macroscopy, angiography and microscopy. Vascular density, inflammatory cell density, gradient of fibrosis and epithelial thickness were determined via immunohistochemical assay. Results: Macroscopic stasis zone tissue viability (32 + 3.28%, 57 + 4.28%) (p<0.01), average number of vessels (10.28 +/- 1.28, 19.43 +/- 1.72) (p<0.01), capillary count (15.67 +/- 1.97, 25.35 +/- 2.15) (p<0.01) vascular density (1.55 +/- 0.38, 2.14 +/- 0.45) (p<0.01) epithelial thickness (0.014 +/- 0.009mm, 0.024 +/- 0.0011mm) were higher on ADSVF side. Fibrosis gradient (1.87 +/- 0.51, 1.50 +/- 0.43) (p<0.01) and inflammatory cell density (1.33 +/- 0.40, 1.20 +/- 0.32) (p<0.01) were higher on the PBS side. Conclusion: Macroscopic and microscopic findings determined that ADSVF has a statistically significant benefit for salvaging stasis zone on acute burn injuries. (c) 2017 Elsevier Ltd and ISBI. All rights reserved.
Effect of Mural or Intra-Arterial Injection Adipose Derived Stromal Fraction on TNBS-Induced Colitis: An Experimental Study
(2019) Tugan, Tezcaner; Aydin, Huseyin Onur; Uysal, Cagri A.; Ozgun, Gonca; Ozer, Huriye Eda Ozturan; Ekici, Yahya; Haberal, Mehmet A.
Effects of topical Coenzyme Q10, Xanthan Gum and Sodium Hyaluronate on corneal epithelial wound healing
(2021) Asena, Leyla; Gokgoz, Gulsah; Helvacioglu, Fatma; Ozgun, Gonca; Deniz, Emine Ebru; Altinors, Dilek Dursun; 0000-0002-6848-203X; 0000-0002-4837-7937; 0000-0002-6026-0045; 34134604; E-5914-2016; AAY-7932-2021; AAH-8887-2021
Background: The aim was to compare the effects of three different eye drops on corneal epithelial wound healing in an experimental model. Methods: Twenty-four eyes of 24 female BALB/c mice were included. A 2 mm central corneal epithelial defect was created. Topical Coenzyme Q10 + Vitamin E D-alpha-TPGS 4 x 1 was applied to Group A (n = 6), topical Sodium hyaluronate + Xanthan Gum + 0.3% Nethylmicine 4 x 1 to Group B (n = 6) and topical Sodium hyaluronate 4 x 1 to Group C (n = 6). Group D (n = 6) was the control group without treatment. Clinical scoring according to corneal fluorescein staining and histopathological evaluations was performed. Results: Clinical scores according to corneal fluorescein staining were similar in all groups on days 1 (p = 0.05), 2 (p = 0.15) and 3 (p = 0.62). Electron microscopy revealed disruption of intercellular junctions between corneal epithelial cells and intracellular vacuole formation in all groups except Group A. Corneal epithelial thickness and superficial epithelial microvillus arrangement were close to normal in Group A. Conclusion: Although there was no difference in clinical scores between groups, electron microscopy revealed a better organised epithelium with normal configuration of microvilli and less vacuolisation in Group A
Enhancer of zeste homologue 2 (EZH2) expression in synovial sarcomas as a promising indicator of prognosis
(2017) Ozgun, Gonca; Yalcinkaya, Ulviye; Ugras, Nesrin; Ocakoglu, Gokhan; Deligonul, Adem; Cetintas, Sibel Kahraman; Bilgen, Muhammed Sadik; 28738014
Synovial sarcoma (SS) is a type of soft-tissue sarcoma, often linked to poor survival. Although overexpression of enhancer of zeste homologue 2 (EZH2) has been associated with poor prognosis in different tumors, a few studies investigated this link in SS. Here, we analyzed the relationship between EZH2 expression and prognostic factors in SS. We included 29 patients with SS. Immunostaining of EZH2 was performed with (D2C9) XP (TM) Rabbit mAb antibody, and the results were classified as low EZH2 expression (negative or weak expression) and high EZH2 expression category (moderate or strong expression). Analysis of survival in relation to prognostic factors was performed with Kaplan-Meier survival curves and Cox proportional hazard regression analysis. Our sample included 19/29 female and 10/29 male patients, with age range 16-63 years. The tumor diameter ranged from 2 to 15 cm. Necrosis was observed in 15/29 cases. Sixteen cases had > 10 mitoses per 50 high-power fields (HPFs). Out of 29 cases, 14 showed low and 15 had high EZH(2) expression. Statistically significant results were obtained for the association between the presence of metastasis and necrosis (p = 0.042), high EZH2 expression and distant metastasis (p = 0.018), high EZH2 expression and necrosis (p = 0.016), and high EZH2 expression and the tumor size > 5 cm versus tumor size <= 5 cm (p = 0.014). Patients with all of the following: the tumor size <= 5 cm, low EZH2 expression, and without necrosis and distant metastasis had significantly longer survival time. Our results are consistent with previous studies, suggesting that EZH(2) overexpression is an indicator of poor prognosis in SS.
Epstein-Barr Virus-Positive T-Cell Lymphoma Characterized by Intestinal Involvement With Multiple Perforation in an Adult Renal Allograft Recipient: Two Case Reports
(2022) Bayik, Pelin; Ozdemir, B. Handan; Ozgun, Gonca; Kayaselcuk, Fazilet; Yildirim, Sedat; Haberal, Mehmet; 0000-0002-3462-7632; AAJ-8097-2021
Gastrointestinal Stromal Tumors: A Clinicopathologica and Immunohistochemical Study of 65 Cases
(2018) Tepeoglu, Merih; Ozgun, Gonca; Tunca, Muzeyyen Zeyneb; Tezcaner, Tugan; Ozdemir, Binnaz Handan; 0000-0002-7528-3557; 29630088; X-8540-2019
Objective: Hie clinical behavior of gastrointestinal stromal tumors is divergent. The aim of the present study was to define the clinicopathological features that determine the patient's outcome. Material and Method: Sixty-five gastrointestinal stromal tumors were reviewed with their histological, immunohistochemical and clinical features and compared with their clinical outcome statistically. Results: Tumors were located in the stomach (n=39, 60%), small intestine (n=22, 33.8%) and large intestine (n=4, 6.2%). Immunohistochemically, CD 117 positivity was found in 90.8%, whereas CD34, Smooth muscle actin, Desmin and S100 positivity was found in 73.3%, 61.7%, 11.7% and 28.3% of tumors respectively. All six "CD 117-negative" cases expressed DOG-1. The mean Ki-67 proliferation index was 8.69%+/- 12.76. Liver metastasis was detected in seven cases. A significant association was detected between decreased mean survival time and increased tumor size (p<0.001), large bowel localization (p-0.047), mitosis (p<0.001), the presence of necrosis (p=0.001), metastasis (p=0.033), Ki-67 proliferation index (p-0.002) and risk category (p<0.001). CD 34 positivity was mostly seen in the stomach (p-0.001), and CD 34 positive tumors had longer overall survival (92.85.+/- 5.77 months versus 67.21 +/- 13.68 months) (p=0.046). Higher Ki-67 proliferation index (6%) was also correlated with the presence of metastases (p=0.015). Conclusion: Our study indicates that in addition to well-known risk factors such as increased tumor size, high mitotic activity and metastasis; higher Ki-67 proliferation index, the presence of necrosis, and CD34 negativity also correlate with shorter survival time.
Global impact of the COVID-19 pandemic on cytopathology practice: Results from an international survey of laboratories in 23 countries
(2020) Ozgun, Gonca; 33108683
Background To the authors' knowledge, the impact of the coronavirus disease 2019 (COVID-19) pandemic on cytopathology practices worldwide has not been investigated formally. In the current study, data from 41 respondents from 23 countries were reported. Methods Data regarding the activity of each cytopathology laboratory during 4 weeks of COVID-19 lockdown were collected and compared with those obtained during the corresponding period in 2019. The overall number and percentage of exfoliative and fine-needle aspiration cytology samples from each anatomic site were recorded. Differences in the malignancy and suspicious rates between the 2 periods were analyzed using a meta-analytical approach. Results Overall, the sample volume was lower compared with 2019 (104,319 samples vs 190,225 samples), with an average volume reduction of 45.3% (range, 0.1%-98.0%). The percentage of samples from the cervicovaginal tract, thyroid, and anorectal region was significantly reduced (P < .05). Conversely, the percentage of samples from the urinary tract, serous cavities, breast, lymph nodes, respiratory tract, salivary glands, central nervous system, gastrointestinal tract, pancreas, liver, and biliary tract increased (P < .05). An overall increase of 5.56% (95% CI, 3.77%-7.35%) in the malignancy rate in nongynecological samples during the COVID-19 pandemic was observed. When the suspicious category was included, the overall increase was 6.95% (95% CI, 4.63%-9.27%). Conclusions The COVID-19 pandemic resulted in a drastic reduction in the total number of cytology specimens regardless of anatomic site or specimen type. The rate of malignancy increased, reflecting the prioritization of patients with cancer who were considered to be at high risk. Prospective monitoring of the effect of delays in access to health services during the lockdown period is warranted.
Hepatic Estrogen Receptor Expression Prevents Liver Fibrosis through Decreasing the Risk of Early Activation of Hepatic Stellate Cells
(2018) Ozdemir, B. Handan; Ozgun, Gonca; Akdur, Aydincan; Moray, Gokhan; Haberal, Mehmet; 0000-0002-7528-3557; 0000-0002-8726-3369; 0000-0003-2498-7287; 0000-0002-3462-7632; X-8540-2019; AAA-3068-2021; AAE-1041-2021; AAJ-8097-2021
HEPATOCYTE GROWTH FACTOR (HGF) PREVENTS THE APOPTOTIC AND ANTI-ANGIOGENIC EFFECT OF HYPERCHOLESTEROLEMIA ON HEPATOCYTES IN LIVER ALLOGRAFTS
(2020) Ozdemir, B. Handan; Ozgun, Gonca; Polat, Aysegul Yucel; Haberal, Nihan; Moray, Gokhan; Haberal, Mehmet A.
Histopathological Changes of Neoadjuvant Chemoradiation and Relation with the Pre-Treatment Tumor Stage in Rectal Carcinoma
(2017) Ozgun, Gonca; Atalay, Fatma Oz; Ugras, Nesrin; Yerci, Omer
Objective: Neoadjuvant chemoradiotherapy has considered one of the standard treatment modalities for locally advanced rectal cancers. Chemoradiotherapy has a variety of different effects and responses on tumor, tumor bed and peritumoral tissues. The purpose of the present study was to evaluate the stromal responses in tumor bed between the different treatment modalities and different clinical T stages. Methods: Fifty-seven consecutive patients with median age of 62.4 years were treated for rectal adenocarcinoma between January 2005 and July 2012 in Uludag University Medical Faculty. Twenty-three of the patients were treated with neoadjuvant chemoradiation therapy and following surgery, 34 patients treated with surgery only. Results: When we compared the stromal responses in the tumor bed between the two different treatment modalities, the amount of fibrosis and intensity of inflammatory cell infiltration were found considerably marked. The existence of calcification, hemosiderin-laden macrophages and mucin lakes were found also significant marked. There was no difference found in between the patients with different clinical stages which were received neoadjuvant CRT. Conclusion: The stromal response in the tumor bed increases with the neoadjuvant chemoradiotherapy but the excess of the response doesn't have any relation with the clinical T stage.
The Impact of Histopathological Features of Primary Tumor to the Long-Term Outcome of Liver Transplants for Hepatocellular Carcinoma: A 10-Year Follow-Up
(2017) Ozgun, Gonca; Ozdemir, B. Handan; Kirnap, Mahir; Ozcay, Figen; Haberal, Mehmet; 0000-0002-7528-3557; 0000-0002-5214-516X; 0000-0002-3462-7632; X-8540-2019; AAH-9198-2019; ABG-5684-2020; AAJ-8097-2021
Importance of Liver Biopsy Findings on Prognosis of Kidney Transplant Patients
(2016) Ozgun, Gonca; Ozdemir, Binnaz Handan; Tunca, Muzeyyen Zeyneb; Borcek, Pelin; Haberal, Mehmet; 0000-0002-7528-3557; 0000-0002-3462-7632; 27805508; X-8540-2019; AAJ-8097-2021
(O)bjectives: Chronic hepatitis infection among kidney transplant recipients is not infrequent, with those with hepatitis C virus infection having worse survival. Here, we evaluated liver biopsy changes and its effects on prognosis in kidney transplant recipients. Materials and Methods: Patients with liver biopsies were selected from 1275 kidney transplant recipients who were treated at Baskent University from January 1990 to December 2012. Demographic and clinical findings were evaluated, including age, sex, liver biopsy findings, amyloid and hemosiderin accumulation, and patient survival. Results: Among 1275 renal transplant patients, only 149 patients had liver biopsies. Of 149 patients, 68 patients (45.3%) had liver biopsy only before and 81 patients had liver biopsy after transplant, with 20 of the 81 patients also having biopsy before transplant. The 81 patients who had a liver biopsy after renal transplant were included in the study. In our patient group, mean follow-up was 166 +/- 29 months, female-to-male ratio was 26/55, and mean age was 30.2 +/- 9.87 years (range, 15-56 y). Only 2 of 81 liver biopsies (2.4%) were diagnosed as normal or nonspecific. Biopsy findings of the remaining 79 patients (97.6%) showed variable pathologies, including hepatocellular damage and minimal cholestatic changes in 29 patients (35.8%), chronic nonviral hepatitis in 9 (11.1%), and viral hepatitis in 41 (50.6%). The mean time between the first liver biopsy taken before transplant and second biopsy after transplant was 44.5 +/- 38.0 months (range, 11-139 mo). Among 81 patients, 6 (7.4%) showed amyloid deposition and 13 (16.0%) showed hemosiderosis. Conclusions: Testing for viral infections is critical in transplant recipients. It is well known that these infections can affect the frequency of rejection episodes and also negatively affect survival in solidorgan transplant recipients. Livers should be evaluated by biopsy even if the variance in liver enzymes or serology is minimal.