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Hydrogen migration at restructuring palladium-silver oxide boundaries dramatically enhances reduction rate of silver oxide.
Heterogeneous catalysts are complex materials with multiple interfaces. A critical proposition in exploiting bifunctionality in alloy catalysts is to achieve surface migration across interfaces separating functionally dissimilar regions. Herein, we demonstrate the enhancement of more than 104 in the rate of molecular hydrogen reduction of a silver surface oxide in the presence of palladium oxide compared to pure silver oxide resulting from the transfer of atomic hydrogen from palladium oxide islands onto the surrounding surface formed from oxidation of a palladium-silver alloy. The palladium-silver interface also dynamically restructures during reduction, resulting in silver-palladium intermixing. This study clearly demonstrates the migration of reaction intermediates and catalyst material across surface interfacial boundaries in alloys with a significant effect on surface reactivity, having broad implications for the catalytic function of bimetallic materials
Rolofylline, an adenosine A1−receptor antagonist, in acute heart failure
Background:
Worsening renal function, which is associated with adverse outcomes, often develops
in patients with acute heart failure. Experimental and clinical studies suggest that
counterregulatory responses mediated by adenosine may be involved. We tested the
hypothesis that the use of rolofylline, an adenosine A1−receptor antagonist, would
improve dyspnea, reduce the risk of worsening renal function, and lead to a more
favorable clinical course in patients with acute heart failure.
Methods:
We conducted a multicenter, double-blind, placebo-controlled trial involving patients
hospitalized for acute heart failure with impaired renal function. Within 24 hours
after presentation, 2033 patients were randomly assigned, in a 2:1 ratio, to receive
daily intravenous rolofylline (30 mg) or placebo for up to 3 days. The primary end
point was treatment success, treatment failure, or no change in the patient’s clinical
condition; this end point was defined according to survival, heart-failure status,
and changes in renal function. Secondary end points were the post-treatment development
of persistent renal impairment and the 60-day rate of death or readmission
for cardiovascular or renal causes.
Results:
Rolofylline, as compared with placebo, did not provide a benefit with respect to the
primary end point (odds ratio, 0.92; 95% confidence interval, 0.78 to 1.09; P=0.35).
Persistent renal impairment developed in 15.0% of patients in the rolofylline group
and in 13.7% of patients in the placebo group (P=0.44). By 60 days, death or readmission
for cardiovascular or renal causes had occurred in similar proportions of patients
assigned to rolofylline and placebo (30.7% and 31.9%, respectively; P=0.86).
Adverse-event rates were similar overall; however, only patients in the rolofylline
group had seizures, a known potential adverse effect of A1-receptor antagonists.
Conclusions:
Rolofylline did not have a favorable effect with respect to the primary clinical composite
end point, nor did it improve renal function or 60-day outcomes. It does not
show promise in the treatment of acute heart failure with renal dysfunction. (Funded
by NovaCardia, a subsidiary of Merck; ClinicalTrials.gov numbers, NCT00328692
and NCT00354458.
Systolic blood pressure reduction during the first 24 h in acute heart failure admission: friend or foe?
Aims:
Changes in systolic blood pressure (SBP) during an admission for acute heart failure (AHF), especially those leading to hypotension, have been suggested to increase the risk for adverse outcomes.
Methods and results:
We analysed associations of SBP decrease during the first 24 h from randomization with serum creatinine changes at the last time-point available (72 h), using linear regression, and with 30- and 180-day outcomes, using Cox regression, in 1257 patients in the VERITAS study. After multivariable adjustment for baseline SBP, greater SBP decrease at 24 h from randomization was associated with greater creatinine increase at 72 h and greater risk for 30-day all-cause death, worsening heart failure (HF) or HF readmission. The hazard ratio (HR) for each 1 mmHg decrease in SBP at 24 h for 30-day death, worsening HF or HF rehospitalization was 1.01 [95% confidence interval (CI) 1.00–1.02; P = 0.021]. Similarly, the HR for each 1 mmHg decrease in SBP at 24 h for 180-day all-cause mortality was 1.01 (95% CI 1.00–1.03; P = 0.038). The associations between SBP decrease and outcomes did not differ by tezosentan treatment group, although tezosentan treatment was associated with a greater SBP decrease at 24 h.
Conclusions:
In the current post hoc analysis, SBP decrease during the first 24 h was associated with increased renal impairment and adverse outcomes at 30 and 180 days. Caution, with special attention to blood pressure monitoring, should be exercised when vasodilating agents are given to AHF patients
Predictors and associations with outcomes of length of hospital stay in patients with acute heart failure: results from VERITAS
Background:
The length of hospital stay (LOS) is important in patients admitted for acute heart failure (AHF) because it prolongs an unpleasant experience for the patients and adds substantially to health care costs.
Methods and Results:
We examined the association between LOS and baseline characteristics, 10-day post-discharge HF readmission, and 90-day post-discharge mortality in 1347 patients with AHF enrolled in the VERITAS program. Longer LOS was associated with greater HF severity and disease burden at baseline; however, most of the variability of LOS could not be explained by these factors. LOS was associated with a higher HF risk of both HF readmission (odds ratio for 1-day increase: 1.08; 95% confidence interval [CI] 1.01–1.16; P = .019) and 90-day mortality (hazard ratio for 1-day increase: 1.05; 95% CI 1.02–1.07; P < .001), although these associations are partially explained by concurrent end-organ damage and worsening heart failure during the first days of admission.
Conclusions:
In patients who have been admitted for AHF, longer length of hospital stay is associated with a higher rate of short-term mortality.
Clinical Trial Registration:
VERITAS-1 and -2: Clinicaltrials.gov identifiers NCT00525707 and NCT00524433
A network analysis to compare biomarker profiles in patients with and without diabetes mellitus in acute heart failure
Aims:
It is unclear whether distinct pathophysiological processes are present among patients with acute heart failure (AHF), with and without diabetes. Network analysis of biomarkers may identify correlative associations that reflect different pathophysiological pathways.
Methods and results:
We analysed a panel of 48 circulating biomarkers measured within 24 h of admission for AHF in a subset of patients enrolled in the PROTECT trial. In patients with and without diabetes, we performed a network analysis to identify correlations between measured biomarkers. Compared with patients without diabetes (n = 1111), those with diabetes (n = 922) had a higher prevalence of ischaemic heart disease and traditional coronary risk factors. After multivariable adjustment, patients with and without diabetes had significantly different levels of biomarkers across a spectrum of pathophysiological domains, including inflammation (TNFR-1a, periostin), cardiomyocyte stretch (BNP), angiogenesis (VEGFR, angiogenin), and renal function (NGAL, KIM-1) (adjusted P-value <0.05). Among patients with diabetes, network analysis revealed that periostin strongly clustered with C-reactive protein and interleukin-6. Furthermore, renal markers (creatinine and NGAL) closely associated with potassium and glucose. These findings were not seen among patients without diabetes.
Conclusion:
Patients with AHF and diabetes, compared with those without diabetes, have distinct biomarker profiles. Network analysis suggests that cardiac remodelling, inflammation, and fibrosis are closely associated with each other in patients with diabetes. Furthermore, potassium levels may be sensitive to changes in renal function as reflected by the strong renal–potassium–glucose correlation. These findings were not seen among patients without diabetes and may suggest distinct pathophysiological processes among AHF patients with diabetes
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