Baseline characteristics of patients in the reduction of events with darbepoetin alfa in heart failure trial (RED-HF)

<p>Aims: This report describes the baseline characteristics of patients in the Reduction of Events with Darbepoetin alfa in Heart Failure trial (RED-HF) which is testing the hypothesis that anaemia correction with darbepoetin alfa will reduce the composite endpoint of death from any cause or hospital admission for worsening heart failure, and improve other outcomes.</p> <p>Methods and results: Key demographic, clinical, and laboratory findings, along with baseline treatment, are reported and compared with those of patients in other recent clinical trials in heart failure. Compared with other recent trials, RED-HF enrolled more elderly [mean age 70 (SD 11.4) years], female (41%), and black (9%) patients. RED-HF patients more often had diabetes (46%) and renal impairment (72% had an estimated glomerular filtration rate <60 mL/min/1.73 m2). Patients in RED-HF had heart failure of longer duration [5.3 (5.4) years], worse NYHA class (35% II, 63% III, and 2% IV), and more signs of congestion. Mean EF was 30% (6.8%). RED-HF patients were well treated at randomization, and pharmacological therapy at baseline was broadly similar to that of other recent trials, taking account of study-specific inclusion/exclusion criteria. Median (interquartile range) haemoglobin at baseline was 112 (106–117) g/L.</p> <p>Conclusion: The anaemic patients enrolled in RED-HF were older, moderately to markedly symptomatic, and had extensive co-morbidity.</p&gt

Turning on ribonucleotide reductase by light-initiated amino acid radical generation

Ribonucleotide reductases (RNRs) catalyze the conversion of nucleotides to deoxynucleotides in all organisms, providing the monomeric precursors required for DNA replication and repair. The class I RNRs are composed of two subunits; the R1 subunit contains the active site for nucleotide reduction and allosteric effector binding sites, whereas the R2 subunit houses the essential diirontyrosyl (Y·) radical cofactor. A major unresolved issue is the mechanism by which the tyrosyl radical on R2 (Y122, Escherichia coli numbering) reversibly generates the transient thiyl radical (S·) on R1 that initiates nucleotide reduction. This intersubunit radical initiation is postulated to occur through a defined pathway involving conserved aromatic amino acids (R2: Y122, W48, Y356; R1: Y731, Y730) over a long distance of 35 Å. A 20-mer peptide identical to the C-terminal tail of R2 (356–375) and containing Y356 is a competitive inhibitor with respect to R2, and it effectively blocks nucleotide reduction. We now report that a 21-mer peptide, in which a tryptophan has been incorporated at the N terminus of the 20th mer, can replace the R2 subunit and initiate nucleotide reduction by photoinitiated radical generation. The deoxynucleotide generated depends on the presence of allosteric effector and is pathway-dependent. Replacement of Y731 of R2 with phenylalanine prevents deoxynucleotide formation. These results provide direct evidence for the chemical competence of aromatic amino acid radicals and the importance of Y356 in R2 in the radical initiation process of the class I RNRs