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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only Subgrading of G2 pancreatic neuroendocrine tumors as 2A (Ki67 3% to < 10%) versus 2B (10% to ≤ 20%) identifies behaviorally distinct subsets in keeping with the evolving management protocols(Springer, 2024) Bağcı, Pelin; Balcı, Serdar; Ohike, Nobuyuki; Sökmensüer, Cenk; Leblebici, Can Berk; Xue, Yue; Reid, Michelle D.; Krasinskas, Alyssa M.; Kooby, David; Maithel, Shishir K.; Sarmiento, Juan; Cheng, Jeanette D.; Tarcan, Zeynep Çağla; Luchini, Claudio; Scarpa, Aldo; Baştürk, Olca; Eren, Özgür Can; Saka, Burcu; Taşkın, Orhun Çığ; Kapran, Yersu; Adsay, Nazmi Volkan; School of MedicineBackground Grade 1/2 PanNETs are mostly managed similarly, typically without any adjunct treatment with the belief that their overall metastasis rate is low. In oncology literature, Ki67-index of 10% is increasingly being used as the cutoff in stratifying patients to different protocols, although there are no systematic pathology-based studies supporting this approach. Methods Ki67-index was correlated with clinicopathologic parameters in 190 resected PanNETs. A validation cohort (n = 145) was separately analyzed. Results In initial cohort, maximally selected rank statistics method revealed 12% to be the discriminatory cutoff (close to 10% rule of thumb). G2b cases had liver/distant metastasis rate of almost threefold higher than that of G2a and showed significantly higher frequency of all histopathologic signs of aggressiveness (tumor size, perineural/vascular invasion, infiltrative growth pattern, lymph node metastasis). In validation cohort, these figures were as striking. When all cases were analyzed together, compared with G1, the G2b category had nine times higher liver/distant metastasis rate (6.1 vs. 58.5%; p < 0.001) and three times higher lymph node metastasis rate (20.5 vs. 65.1%; p < 0.001). Conclusions G2b PanNETs act very similar to G3, supporting management protocols that regard them as potential therapy candidates. Concerning local management, metastatic behavior in G2b cases indicate they may not be as amenable for conservative approaches, such as watchful waiting or enucleation. This substaging should be considered into diagnostic guidelines, and clinical trials need to be devised to determine the more appropriate management protocols for G2b (10% to <= 20%) group, which shows liver/distant metastasis in more than half of the cases, which at minimum warrants closer follow-up.Publication Metadata only Utility of diffusion tensor imaging and generalized q-sampling imaging for predicting short-term clinical effect of deep brain stimulation in Parkinson's disease(SPRINGER WIEN, 2024) Hasimoglu, Ozan; Balsak, Serdar; Mutlu, Samet; Karagulle, Mehmet; Kose, Fadime; Altinkaya, Ayca; Tugcu, Bekir; Kocak, Burak; Yüzkan, Sabahattin; Koç University HospitalPurpose To assess whether diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI) metrics could preoperatively predict the clinical outcome of deep brain stimulation (DBS) in patients with Parkinson's disease (PD). Methods In this single-center retrospective study, from September 2021 to March 2023, preoperative DTI and GQI examinations of 44 patients who underwent DBS surgery, were analyzed. To evaluate motor functions, the Unified Parkinson's Disease Rating Scale (UPDRS) during on- and off-medication and Parkinson's Disease Questionnaire-39 (PDQ-39) scales were used before and three months after DBS surgery. The study population was divided into two groups according to the improvement rate of scales: >= 50% and < 50%. Five target regions, reported to be affected in PD, were investigated. The parameters having statistically significant difference were subjected to a receiver operating characteristic (ROC) analysis. Results Quantitative anisotropy (qa) values from globus pallidus externus, globus pallidus internus (qa_Gpi), and substantia nigra exhibited significant distributional difference between groups in terms of the improvement rate of UPDRS-3 scale during on-medication (p = 0.003, p = 0.0003, and p = 0.0008, respectively). In ROC analysis, the best parameter in predicting DBS response included qa_Gpi with a cut-off value of 0.01370 achieved an area under the ROC curve, accuracy, sensitivity, and specificity of 0.810, 73%, 62.5%, and 85%, respectively. Optimal cut-off values of >= 0.01864 and <= 0.01162 yielded a sensitivity and specificity of 100%, respectively. Conclusion The imaging parameters acquired from GQI, particularly qa_Gpi, may have the ability to non-invasively predict the clinical outcome of DBS surgery.Publication Metadata only Reversible fetal tracheal occlusion in mice: a novel minimal invasive technique(Elsevier, 2021) N/A; N/A; N/A; N/A; Aydın, Emrah; Torlak, Nilhan; Yıldırım, Alkım; Bozkurt, Elif Gökçen; Faculty Member; PhD Student; Undergraduate Student; Undergraduate Student; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); N/A; N/A; N/A; School of Medicine; Graduate School of Health Sciences; School of Medicine; School of Medicine; 32059; N/A; N/A; N/ABackground: There is a certain need for reversible, cheap, and reproducible animal models for understanding the impact of tracheal occlusion (TO) in the congenital diaphragmatic hernia and pathophysiology. We aimed to present an easy, reversible, and minimally invasive murine TO model with optimized time points for introduction and removal of TO. Methods: Time-mated C57BL/6 mice underwent laparotomy at embryonic day 16.5 (E16.5) with transuterine TO performed on two fetuses in each uterine horn. In the TO group, the fetuses were harvested at E18.5 without suture removal; the suture was released at E17.5 in the TO-R group, and all fetuses were harvested at E18.5. The lungs of the fetuses were compared by morphometric and histologic analysis. Results: Successful TO was confirmed in 34 of 37 fetuses. Twenty-nine of them survived to E18.5 (90.6%), six of the fetuses had a spontaneous vaginal delivery. Fetal weights were comparable, but there was significant difference in lung weights and lung-to-body weight ratios (0.020 ? 0.006 [control] versus 0.026 ? 0.002 [TO] versus 0.023 ? 0.005 [TO-R]; P = 0.013). DNA/protein and DNA/lung weight ratios were elevated, whereas protein/lung weight ratio was lower in TO compared with the control group. Conclusions: Reversal of fetal transuterine TO at E17.5, which was put at E16.5 in mice, is feasible with comparable outcomes to other current animal models with certain advantages and potential to translate the studies to the human. ? 2020 Elsevier Inc. All rights reserved.