Ewa Łucja Stępień

Prof. Ewa Łucja Stępień

Jagiellonian University - Faculty of Physics, Astronomy and Applied Computer Science - Krakow, Poland
orcid

Research Focus & Metrics

Academic Career Length

29Years (1998-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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10 November 2014 in Bioinformatics
Verified
Journal Article
Open access
PDF file
DKDae-Kyum Kim
Dae-Kyum Kim
JLJaewook Lee
Jaewook Lee
SKSae Rom Kim
Sae Rom Kim
DCDongsic Choi
Dongsic Choi
YYYae Jin Yoon
Yae Jin Yoon
YGYong Song Gho
Yong Song Gho
Motivation: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging. Results: We present an improved version of EVpedia, a public database for EVs research. This community web portal contains a database of publications and vesicular components, identification of orthologous vesicular components, bioinformatic tools and a personalized function. EVpedia includes 6879 publications, 172 080 vesicular components from 263 high-throughput datasets, and has been accessed more than 65 000 times from more than 750 cities. In addition, about 350 members from 73 international research groups have participated in developing EVpedia. This free web-based database might serve as a useful resource to stimulate the emerging field of EV research. Availability and implementation: The web site was implemented in PHP, Java, MySQL and Apache, and is freely available at http://evpedia.info. Contact:ysgho@postech.ac.kr

15 October 2021 in Science Advances
Verified
Journal Article
Open access
PMPawel Moskal
Pawel Moskal
KDKamil Dulski
Kamil Dulski
NCNeha Chug
Neha Chug
CCCatalina Curceanu
Catalina Curceanu
ECEryk Czerwiński
Eryk Czerwiński
WWWojciech Wiślicki
Wojciech Wiślicki
Positronium created in a human body during PET scans hallmarks neoplastic tissues.

1 August 2008 in Diabetes Care
Verified
Journal Article
Open access
AUAnetta Undas
Anetta Undas
IWIlona Wiek
Ilona Wiek
Ewa Łucja StępieńEwa Łucja Stępień
Ewa Łucja Stępień
KZKrzysztof Zmudka
Krzysztof Zmudka
WTWiesława Tracz
Wiesława Tracz
OBJECTIVE—Acute hyperglycemia on admission for acute coronary syndrome worsens the prognosis in patients with and without known diabetes. Postulated mechanisms of this observation include prothrombotic effects. The aim of this study was to evaluate the effect of elevated glucose levels on blood clotting in acute coronary syndrome patients. RESEARCH DESIGN AND METHODS—We studied 60 acute coronary syndrome patients within the first 12 h after pain onset, including 20 subjects with type 2 diabetes, 20 subjects with no diagnosed diabetes but with glucose levels >7.0 mmol/l, and 20 subjects with glucose levels <7.0 mmol/l. We determined generation of thrombin-antithrombin complexes (TATs) and soluble CD40 ligand (sCD40L), a platelet activation marker, at the site of microvascular injury, together with ex vivo plasma fibrin clot permeability and lysis time. RESULTS—The acute coronary syndrome patients with no prior diabetes but elevated glucose levels had increased maximum rates of formation and total production of TATs (by 42.9%, P < 0.0001, and by 25%, P < 0.0001, respectively) as well as sCD40L release (by 16.2%, P = 0.0011, and by 16.3%, P < 0.0001, respectively) compared with those with normoglycemia, whereas diabetic patients had the highest values of TATs and sCD40L variables (P < 0.0001 for all comparisons). Patients with hyperglycemia, with no previously diagnosed diabetes, had longer clot lysis time (by ∼18%, P < 0.0001) similar to that in diabetic subjects, but not lower clot permeability compared with that in normoglycemic subjects. CONCLUSIONS—Hyperglycemia in acute coronary syndrome is associated with enhanced local thrombin generation and platelet activation, as well as unfavorably altered clot features in patients with and without a previous history of diabetes.

1 March 2019 in Physics in Medicine & Biology
Verified
Journal Article
Open access
PDF file
PMPawel Moskal
Pawel Moskal
DKD Kisielewska
D Kisielewska
CCC Curceanu
C Curceanu
ECEryk Czerwiński
Eryk Czerwiński
KDK Dulski
K Dulski
BZB Zgardzińska
B Zgardzińska
A detection system of the conventional PET tomograph is set-up to record data from [Formula: see text] annihilation into two photons with energy of 511 keV, and it gives information on the density distribution of a radiopharmaceutical in the body of the object. In this paper we explore the possibility of performing the three gamma photons imaging based on ortho-positronium annihilation, as well as the possibility of positronium mean lifetime imaging with the J-PET tomograph constructed from plastic scintillators. For this purposes simulations of the ortho-positronium formation and its annihilation into three photons were performed taking into account distributions of photons' momenta as predicted by the theory of quantum electrodynamics and the response of the J-PET tomograph. In order to test the proposed ortho-positronium lifetime image reconstruction method, we concentrate on the decay of the ortho-positronium into three photons and applications of radiopharmaceuticals labeled with isotopes emitting a prompt gamma. The proposed method of imaging is based on the determination of hit-times and hit-positions of registered photons which enables the reconstruction of the time and position of the annihilation point as well as the lifetime of the ortho-positronium on an event-by-event basis. We have simulated the production of the positronium in point-like sources and in a cylindrical phantom composed of a set of different materials in which the ortho-positronium lifetime varied from 2.0 ns to 3.0 ns, as expected for ortho-positronium created in the human body. The presented reconstruction method for total-body J-PET like detector allows to achieve a mean lifetime resolution of ∼40 ps. Recent positron annihilation lifetime spectroscopy measurements of cancerous and healthy uterine tissues show that this sensitivity may allow to study the morphological changes in cell structures.

1 February 2008 in Atherosclerosis
Verified
Journal Article
Closed access
AUAnetta Undas
Anetta Undas
KSKonstanty Szułdrzynski
Konstanty Szułdrzynski
Ewa Łucja StępieńEwa Łucja Stępień
Ewa Łucja Stępień
JZJarosław Zalewski
Jarosław Zalewski
JGJacek Godlewski
Jacek Godlewski
KZKrzysztof Zmudka
Krzysztof Zmudka

1 October 2020 in PET Clinics
Verified
Journal Article
Open access
PMPawel Moskal
Pawel Moskal
Ewa Łucja StępieńEwa Łucja Stępień
Ewa Łucja Stępień
Total-body PET opens a new diagnostic paradigm with prospects for personalized disease treatment, yet the high cost of the current crystal-based PET technology limits dissemination of total-body PET in hospitals and even in research clinics. The J-PET tomography system is based on axially arranged low-cost plastic scintillator strips. It constitutes a realistic cost-effective solution of a total-body PET for broad clinical applications. High sensitivity of total-body J-PET and triggerless data acquisition enable multiphoton imaging, opening possibilities for multitracer and positronium imaging, thus promising quantitative enhancement of specificity in cancer and inflammatory disease assessment.