676 research outputs found

    The differences in the relationship between diastolic dysfunction, selected biomarkers and collagen turn-over in heart failure patients with preserved and reduced ejection fraction

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    Background: The aim of the study was to assess the correlation of the selected biomarkers and collagen turn-over indices with advanced echocardiographic parameters among patients with preserved and reduced ejection fraction (EF). Methods: We included 62 patients with the symptomatic heart failure. The patients were divided in to two groups according to the evaluated ejection fraction (EF — Simpson method): heart failure with reduced ejection fraction (HFrEF) group — 30 patients with low EF — 35–50% (16 male, mean age 54.9 ± 12.6), heart failure with preserved ejection fraction (HFpEF) group — 32 patients with EF > 50% (16 male, mean age 62.3 ± 7.6). Clinical evaluation included 6-min walk test, biochemistry, procollagen type I N-terminal propeptide (PINP), procollagen type III N-terminal propetide (PIIINP), matrix metaloproteinase-2 (MMP2), ghrelin, and galectin-3 levels measurements. Echocardiographic examination was performed with analysis of diastolic function and global longitudinal strain (GLS). Results: The GLS in the HFrEF group was significantly lower than in the HFpEF group at the baseline (GLS: 9.56 vs. 16.03, p < 0.01). There was a strong negative correlation of the PIIINP and GLS in HFrEF group (r = –0.74, p = 0.005), but only a moderate negative correlation in HFpEF (r = –0.55, p = 0.02). In the HFrEF group, there was a moderate negative correlation between the baseline level of galectin-3 and GLS (r = –0.59, p = 0.03). The correlation of ghrelin and tissue inhibitor of matrix metalloproteinase-1 with EF in the HFrEF group was moderate and statistically significant (r = 0.62, p = 0.02 and r = –0.63, p = 0.02, respectively). Conclusions: Procollagen type III peptide has a strong negative correlation with left ventricular GLS. Galectin-3 relationship with strain may indicate novel pathophysiological pathways and requires further investigation.

    Evidence for Different Freeze-Out Radii of High- and Low-Energy Pions Emitted in Au+Au Collisions at 1 GeV/nucleon

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    Double differential production cross sections of negative and positive pions and the number of participating protons have been measured in central Au+Au collisions at 1 GeV per nucleon incident energy. At low pion energies the pi^- yield is strongly enhanced over the pi^+ yield. The energy dependence of the pi^-/pi^+ ratio is assigned to the Coulomb interaction of the charged pions with the protons in the reaction zone. The deduced Coulomb potential increases with increasing pion c.m. energy. This behavior indicates different freeze-out radii for different pion energies in the c.m.~frame.Comment: IKDA is the Institute for Nuclear Physics in Darmstadt/German

    Two-Particle Correlations in Relativistic Heavy-Ion Collisions

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    Two-particle momentum correlations between pairs of identical particles produced in relativistic heavy-ion reactions can be analyzed to extract the space-time structure of the collision fireball. We review recent progress in the application of this method, based on newly developed theoretical tools and new high-quality data from heavy-ion collision experiments. Implications for our understanding of the collision dynamics and for the search for the quark-gluon plasma are discussed.Comment: 44 pages, LaTeX, 11 Figures, uses special style files (included), prepared for Ann. Rev. Nucl. Part. Sci. 49 (1999). Error in Chapt. 1 corrected and a few references adde

    Universal Pion Freeze-out in Heavy-Ion Collisions

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    Based on an evaluation of data on pion interferometry and on particle yields at mid-rapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda_f reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from AGS to RHIC.Comment: 5 pages, 3 figures, revised version resubmitted to PR

    Influence of Impact Parameter on Thermal Description of Relativistic Heavy Ion Collisions at GSI/SIS

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    Attention is drawn to the role played by the size of the system in the thermodynamic analysis of particle yields in relativistic heavy ion collisions at SIS energies. This manifests itself in the non-linear dependence of K+ and K- yields in AAAA collisions at 1 -- 2 A.GeV on the number of participants. It is shown that this dependence can be quantitatively well described in terms of a thermal model with a canonical strangeness conservation. The measured particle multiplicity ratios (pi+/p, pi-/pi+, d/p, K+/pi+ and K+/K- but not eta/pi0) in central Au-Au and Ni-Ni collisions at 0.8 -- 2.0 A.GeV are also explained in the context of a thermal model with a common freeze-out temperature and chemical potential. Including the concept of collective flow a consistent picture of particle energy distributions is derived with the flow velocity being strongly impact-parameter dependent.Comment: revtex, 20 figure
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