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
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
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
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
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
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 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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