Ismini Papageorgiou | Charité - Universitätsmedizin Berlin / Charité Medical University Berlin (original) (raw)

Papers by Ismini Papageorgiou

Glia, 2011

Glutamine synthetase (GS) is an astrocytic enzyme, which catalyzes the synthesis of glutamine fro... more Glutamine synthetase (GS) is an astrocytic enzyme, which catalyzes the synthesis of glutamine from glutamate and ammonia. In the central nervous system, GS prevents glutamate-dependent excitotoxicity and detoxifies nitrogen. Reduction in both expression and activity of GS was reported in the hippocampus of patients with temporal lobe epilepsy (TLE), and this reduction has been suggested to contribute to epileptogenesis. In this study, we characterized hippocampal GS expression in the pilocarpine model of TLE in Wistar rats by means of stereology and morphometric analysis. Neither the GS positive cell number nor the GS containing cell volume was found to be altered in different hippocampal subregions of chronic epileptic rats when compared with controls. Instead, redistribution of the enzyme at both intracellular and tissue levels was observed in the epileptic hippocampus; GS was expressed more in proximal astrocytic branches, and GS expressing astrocytic somata was located in closer proximity to vascular walls. These effects were not due to shrinkage of astrocytic processes, as revealed by glial fibrillary acidic protein staining. Our results argue for GS redistribution rather than downregulation in the rat pilocarpine model of TLE. The potential contribution of increased GS perivascular affinity to the pathogenesis of epilepsy is discussed as well. V

Copyright © 2011 Richard Kovács et al. This is an open access article distributed under the Creat... more Copyright © 2011 Richard Kovács et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Proper neuronal functioning depends on a strictly regulated interstitial environment and tight coupling of neuronal and metabolic activity involving adequate vascular responses. These functions take place at the blood brain barrier (BBB) composed of endothelial cells, basal lamina covered with pericytes, and the endfeet of perivascular astrocytes. In conventional in vitro models of the BBB, some of these components are missing. Here we describe a new model system for studying BBB and neurovascular coupling by using confocal microscopy and fluorescence staining protocols in organotypic hippocampal slice cultures. An elaborated network of vessels is retained in culture in spite of the absence of blood flow. Application of calcein-AM ei...

International Journal of Legal Medicine

Determining majority plays a key role for forensic age diagnostics in living individuals. Recent ... more Determining majority plays a key role for forensic age diagnostics in living individuals. Recent data suggest that magnetic resonance imaging (MRI) of the proximal tibial epiphysis (PTE) may be a suitable alternative or at least an additional tool to clarify whether an individual has reached majority. However, the reference data situation is still sparse. Hence, the present dual center study retrospectively analyzed routine MRI of the knee in 413 cases (214 males and 199 females) of a Western Caucasian population aged between 12 and 25 years. MRI was performed at 1.5 and 3.0 T clinical scanners using T1- and T2-weighted sequences. The classification system by Vieth et al. (Eur Radiol 2018; 28:3255–3262) was applied for determining the ossification stages of the PTE. Intra-observer agreement was “very good” (κ = 0.931), and inter-observer agreement was “good” (κ = 0.798). Minimum ages above the age of 18 years were observed with the final stage (stage 6) in either sex (20.27 years in...

Poster: "ECR 2018 / C-1451 / Effect of lesions size on PIRADS-Scoring: Is there a size relat... more Poster: "ECR 2018 / C-1451 / Effect of lesions size on PIRADS-Scoring: Is there a size related diagnostic improvement of PIRADS V2 vs. V1?" by: "A. Malich, I. papageorgiou, D. Kovacevic, A. Kott; Nordhausen/DE"

International Journal of Environmental Research and Public Health, 2021

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Poster: "ECR 2017 / C-2777 / Diagnostic role of CAD-based analysis of composition of segment... more Poster: "ECR 2017 / C-2777 / Diagnostic role of CAD-based analysis of composition of segmented tumours, peak uptake, time to peak and others of only MR-visible histologically proven breast lesions" by: "A. Malich, S. Peix, I. papageorgiou, U. K. M. Teichgraber; Nordhausen/DE"

Highlights d Viruses induce depressive behavior and ISG15 expression at the blood-brain barrier d... more Highlights d Viruses induce depressive behavior and ISG15 expression at the blood-brain barrier d IFNAR1 expression on neural cells is not involved in IFNb-induced sickness behavior d IFNAR1 expression on brain endothelial and epithelial cells drives behavioral changes d Brain endothelia-and epithelia-derived CXCL10 inhibits hippocampal synaptic plasticity

Big Data in Multimodal Medical Imaging, 2019

Poster: "ECR 2018 / C-1430 / Contrast media application at whole body MRI in oncology: does ... more Poster: "ECR 2018 / C-1430 / Contrast media application at whole body MRI in oncology: does it really matter?" by: "A. Malich, I. papageorgiou, D. Kovacevic, D. Wiech, A. Kott; Nordhausen/DE"

Introdruction: Rapid thrombectomy for acute ischemic stroke caused by large vessel occlusion lead... more Introdruction: Rapid thrombectomy for acute ischemic stroke caused by large vessel occlusion leads to improved outcome. Optimizing intrahospital management might diminish treatment delays. To examine if one-stop management reduces intrahospital treatment delays and improves functional outcome of acute stroke patients with large vessel occlusion. Methods: We performed a single center, observational study from June 2016 to November 2018. Imaging was acquired with the latest generation angiography suite at a comprehensive stroke center. Two-hundred-thirty consecutive adults with suspected acute stroke presenting within 6 hours after symptom onset with a moderate to severe National Institutes of Health Stroke Scale (≥ 10 in 2016; ≥ 7 since January 2017) were directly transported to the angiography suite by bypassing multidetector CT. Noncontrast flat-detector CT and biphasic flat-detector CT angiography were acquired with an angiography system. In case of a large vessel occlusion patien...

Poster: "ECR 2018 / C-1607 / Influence of size and location on diagnostic value of T2w in mu... more Poster: "ECR 2018 / C-1607 / Influence of size and location on diagnostic value of T2w in multiparametric prostate MRI" by: "A. Malich1, A. Kott1, J. Feger1, D. Kovacevic1, I. papageorgiou1, U. K. M. Teichgraber2; 1Nordhausen/DE, 2Jena/DE"

Poster: "ECR 2018 / C-0347 / Whole-body MRI for the detection of bone metastasis in breast c... more Poster: "ECR 2018 / C-0347 / Whole-body MRI for the detection of bone metastasis in breast cancer: does the static field strength or application of enhancer improve the diagnostic efficacy? " by: " I. papageorgiou , S. Peix, D. Predel, A. Streck, A. Kott, A. Malich; Nordhausen/DE"

Poster: "ECR 2017 / B-0693 / Effect of PIRADSv2 instead of PIRADSv1 in the analysis of multi... more Poster: "ECR 2017 / B-0693 / Effect of PIRADSv2 instead of PIRADSv1 in the analysis of multiparametric prostate MRI at 310 prostatic lesions proven by MR-guided biopsy at 3T vs 1.5T" by: "A. Malich, I. Papageorgiou, R. L. Chelaru, A. Kott; Nordhausen/DE"

The reconstruction in MRI assumes a uniform radio-frequency field. However, this is violated, whi... more The reconstruction in MRI assumes a uniform radio-frequency field. However, this is violated, which leads to anatomically inconsequential intensity non-uniformities. An anatomic region can be imaged with multiple contrasts that result in different non-uniformities. A method is presented for the joint intensity uniformity restoration of two such images. The effect of the intensity distortion on the auto-co-occurrence statistics of each image as well as on the joint-co-occurrence statistics of the two images is modeled. Their non-stationary deconvolution gives Bayesian coring estimates of the images. Further constraints for smoothness, stability, and validity of the non-uniformity estimates are also imposed. The effectiveness and accuracy of the method has been demonstrated extensively with both BrainWeb phantom images as well as with real brain anatomic data of 29 Parkinson’s disease patients.

Poster: "ECR 2018 / C-0349 / The diagnostic accuracy of T2-w, DWI and perfusion kinetics in ... more Poster: "ECR 2018 / C-0349 / The diagnostic accuracy of T2-w, DWI and perfusion kinetics in PI-RADS: do we need gadolinium enhancer for the diagnosis of prostate cancer?" by: "I. papageorgiou, C. Kurrat, J. Feger, A. Kott, A. Malich; Nordhausen/DE"

Symmetry

Breakthrough advances in informatics over the last decade have thoroughly influenced the field of... more Breakthrough advances in informatics over the last decade have thoroughly influenced the field of immunology. The intermingling of machine learning with wet lab applications and clinical results has hatched the newly defined immunoinformatics society. Immunoinformatics of the central neural system, referred to as neuroimmunoinformatics (NII), investigates symmetrical and asymmetrical interactions of the brain-immune interface. This interdisciplinary overview on NII is addressed to bioscientists and computer scientists. We delineate the dominating trajectories and field-shaping achievements and elaborate on future directions using bridging language and terminology. Computation, varying from linear modeling to complex deep learning approaches, fuels neuroimmunology through three core directions. Firstly, by providing big-data analysis software for high-throughput methods such as next-generation sequencing and genome-wide association studies. Secondly, by designing models for the predi...

Journal of Imaging, Dec 15, 2017

The reconstruction of MRI data assumes a uniform radio-frequency field. However, in practice, the... more The reconstruction of MRI data assumes a uniform radio-frequency field. However, in practice, the radio-frequency field is inhomogeneous and leads to anatomically inconsequential intensity non-uniformities across an image. An anatomic region can be imaged with multiple contrasts reconstructed independently and be suffering from different non-uniformities. These artifacts can complicate the further automated analysis of the images. A method is presented for the joint intensity uniformity restoration of two such images. The effect of the intensity distortion on the auto-co-occurrence statistics of each image as well as on the joint-co-occurrence statistics of the two images is modeled and used for their non-stationary restoration followed by their back-projection to the images. Several constraints that ensure a stable restoration are also imposed. Moreover, the method considers the inevitable differences between the signal regions of the two images. The method has been evaluated extensively with BrainWeb phantom brain data as well as with brain anatomic data from the Human Connectome Project (HCP) and with data of Parkinson's disease patients. The performance of the proposed method has been compared with that of the N4ITK tool. The proposed method increases tissues contrast at least 4.62 times more than the N4ITK tool for the BrainWeb images. The dynamic range with the N4ITK method for the same images is increased by up to +29.77%, whereas, for the proposed method, it has a corresponding limited decrease of −1.15%, as expected. The validation has demonstrated the accuracy and stability of the proposed method and hence its ability to reduce the requirements for additional calibration scans.

Journal of Physics: Conference Series

Parkinson's Disease (PD) is a degenerative disorder of the brain. This study presents an MRI-... more Parkinson's Disease (PD) is a degenerative disorder of the brain. This study presents an MRI-based brain atlas of PD to characterize associated alterations for diagnostic and interventional purposes. The atlas standardizes primarily the implicated subcortical regions such as the globus pallidus (GP), substantia nigra (SN), subthalamic nucleus (STN), caudate nucleus (CN), thalamus (TH), putamen (PUT), and red nucleus (RN). The data were 3.0 T MRI brain images from 16 PD patients and 10 matched controls. The images used were T1-weighted (T 1 w), T2-weighted (T 2 w) images, and Susceptibility Weighted Images (SWI). The T1w images were the reference for the inter-subject non-rigid registration available from 3DSlicer. Anatomic labeling was achieved with BrainSuite and regions were refined with the level sets segmentation of ITK-Snap. The subcortical centers were analyzed for their volume and signal intensity. Comparison with an age-matched control group unravels a significant PD-related T1w signal loss in the striatum (CN and PUT) centers, but approximately a constant volume. The results in this study improve MRI based PD localization and can lead to the development of novel biomarkers.

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