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Öğe Demonstration of ventricular myocardial extensions into the pulmonary artery and aorta beyond the ventriculo-arterial junction(Blackwell Publishing, 2007) Hasdemir, Can; Aktas, Safiye; Govsa, Figen; Aktas, Ekin O.; Kocak, Aytac; Bozkaya, Yasmin T.; Demirbas, Muge I.; Ulucan, Cem; Ozdogan, Oner; Kayikcioglu, Meral; Can, Levent H.; Payzin, SerdarBackground: A subgroup of outflow tract (OT) ventricular tachycardias (VT) originate from the aortic sinuses or the main stem of the pulmonary artery. The anatomic substrate for these tachycardias is unknown. The aim of this study was to investigate the presence of ventricular myocardial extensions (VME) into the pulmonary artery (PA) and aorta (Ao) beyond the ventriculo-arterial junction (VAJ) and determine the anatomical and histological characteristics of these muscle extensions. Methods: Ninety-five consecutive human hearts obtained at autopsy were studied. Longitudinal strips of tissue containing each cusp, aortic, and pulmonary artery walls and left and right ventricular outflow tracts were excised and histologically analyzed. Anatomical measurements, including length and thickness of VMEs, obtained at autopsy, were made. Results: VMEs beyond the VAJ were found in 21 of 95 (22%) patients studied. VMEs were found in 16 of 95 PAs (17%) and 7 of 95 Aos (7%) were examined. VMEs were located within the adventitia in 23 (88%) and on the epicardial surface in three (12%). The majority of VMEs were in continuity with the underlying ventricular OT muscle tissue. Myocellular hypertrophy and fibrosis were present in 19 (73%) and fatty tissue between the layers of VME in 18 (69%). Clinical data were available in 14 of 21 patients with positive VME. None of the patients (clinical data available group) had history of cardiac disease or signs or symptoms (palpitations or syncope) of cardiac disease. Conclusions: VMEs into the PA and Ao beyond the VAJ are relatively common. It seems that their mere presence does not predispose to OT VTs. There are probably intrinsic arrhythmogenic properties in tissues specific to these regions in those patients who develop OT VTs.Öğe MicroRNA-17, MicroRNA-19b, MicroRNA-146a, MicroRNA-302d Expressions in Hepatoblastoma and Clinical Importance(Lippincott Williams & Wilkins, 2019) Ecevit, Cigdem O.; Aktas, Safiye; Yildirim, Hulya Tosun; Demirag, Bengu; Erbay, Ayse; Karaca, Irfan; Celik, Ahmet; Demir, Ayse Banu; Ercetin, Ayse Pinar; Olgun, NurHepatoblastoma (HB) is the most common liver malignancy in children. The prognosis changes according to the histologic subtypes of HB. In the present study, we aimed to characterize the expression level of selected microRNAs (miRNAs) in HB as well as in histologic subtypes, and to consider the association with the prognosis. A total of 22 HB tumor samples, subtyped as fetal (n= 16) and embryonal (n= 6), and 10 nontumorous surrounding liver samples were evaluated in this study. Expressions of miR-17, miR-146a, miR-302d, and miR-19b were analyzed in 22 HB tumor samples and 10 nontumorous surrounding liver samples by quantitative real-time polymerase chain reaction. Lower miRNA-17 expression levels were obtained in tumor samples in comparison with nontumorous surrounding liver samples (P= 0.028). Lower miRNA-17 expression was significant for predicting prognosis in HB patients (area under receiver-operator characteristic curve= 0.875, P= 0.044). A higher-level of miR-19b was found in embryonal samples (P= 0.008). Overall and event-free survival was not found to correlate with miRNA expression levels (P> 0.05). This research finds miRNA-17 and miRNA-19b expression levels can provide important data on diagnosis and prognosis in HB showing different clinical behaviors.Öğe Value of electron microscopy epon block banking in paediatric pathology(Springer, 2007) Aktas, Safiye; Diniz, Gulden; Aktug, Huseyin