At the current daily price sacubitril/valsartan may not represent good value for limited healthcare dollars compared to enalapril in reducing cardiovascular morbidity and mortality in HF in the Singapore healthcare setting. This study highlights the cost-benefit trade-off that healthcare professionals and patients face when considering therapy.

Heat shock protein 90 (Hsp90) is a promising cancer drug target, as multiple oncogenic proteins are destabilized simultaneously when it loses its activity in tumor cells. Highly selective Hsp90 inhibitors, including the natural antibiotics geldanamycin (GdA) and radicicol (RAD), inactivate this essential molecular chaperone by occupying its nucleotide binding site. Often cancer drug therapy is compromised by the development of resistance, but a resistance to these Hsp90 inhibitors should not arise readily by mutation of those amino acids within Hsp90 that facilitate inhibitor binding, as these are required for the essential ATP binding/ATPase steps of the chaperone cycle and are tightly conserved. Despite this, the Hsp90 of a RAD-producing fungus is shown to possess an unusually low binding affinity for RAD but not GdA. Within its nucleotide binding site a normally conserved leucine is replaced by isoleucine, though the chaperone ATPase activity is not severely affected. Inserted into the Hsp90 of yeast, this conservative leucine to isoleucine substitution recreated this lowered affinity for RAD in vitro. It also generated a substantially enhanced resistance to RAD in vivo. Co-crystal structures reveal that the change to isoleucine is associated with a localized increase in the hydration of an Hsp90-bound RAD but not GdA. To the best of our knowledge, this is the first demonstration that it is possible for Hsp90 inhibitor resistance to arise by subtle alteration to the structure of Hsp90 itself.

The isopenicillin N synthase of Cephalosporium acremonium (cIPNS) involves a catalytically important non-heme iron which is coordinated credibly to histidine residues. A comparison of the IPNS genes from various microbial sources indicated that there are seven conserved histidine residues. These were individually replaced by leucine residues through site-directed mutagenesis, and the sites of mutation were confirmed by DNA sequencing. The seven mutant genes were cloned separately into the vector pET24d for expression in Escherichia coli BL21 (DE3), and the proteins were expressed as soluble enzymes. All the resulting mutant enzymes obtained have mobilities of approximately 38 kDa, identical with the wild-type enzyme on SDS-polyacrylamide gel electrophoresis, and were also reactive to cIPNS antibodies. The enzymes were purified by ammonium sulfate precipitation and DEAE-Sephadex A-50 ion exchange chromatography, and these were analyzed for enzyme activity. A group of mutant enzymes, H49L, H64L, H116L, H126L, and H137L, were found to be enzymatically active with reduced activities of 16-93.7%, indicating that they are not essential for catalysis. Two of the mutant enzymes, H216L and H272L, were found to have lost their enzymatic activity completely, indicating that both His-216 and His-272 are crucial for catalysis. It is suggested that these histidines are likely to serve as ligands for binding to the non-heme iron in the IPNS active site. Alignment of the amino acid sequence of IPNS to related non-heme Fe(2+)-requiring enzymes indicated that the two essential histidine residues correspond to two invariant residues located in highly homologous regions. The conservation of the two closely located histidine residues indicates the possible conservation of similar iron-binding sites in these enzymes.

Background Knowledge of decision-making preference of patients and caregivers is needed to facilitate deprescribing. This study aimed to assess the perspectives of caregivers and older adults towards deprescribing in an Asian population. Secondary objectives were to identify and compare characteristics associated with these attitudes and beliefs. Method A cross-sectional survey of two groups of participants was conducted using the Revised Patients’ Attitudes Towards Deprescribing questionnaire. Descriptive results were reported for participants’ characteristics and questionnaire responses from four factors (belief in medication inappropriateness, medication burden, concerns about stopping, and involvement) and two global questions. Correlation between participant characteristics and their responses was analyzed. Results A total of 1,057 (615 older adults; 442 caregivers) participants were recruited from 10 institutions in Singapore. In which 511 (83.0%) older adults and 385 (87.1%) caregivers reported that they would be willing to stop one or more of their medications if their doctor said it was possible, especially among older adults recruited from acute-care hospitals (85.3%) compared with older adults in community pharmacies (73.6%). Individuals who take more than five medications and those with higher education were correlated with greater agreement in inappropriateness and involvement, respectively. Conclusions Clinicians should consider discussing deprescribing with older adults and caregivers in their regular clinical practice, especially when polypharmacy is present. Further research is needed into how to engage older adults and caregivers in shared decision making based on their attitudes toward deprescribing.

Aims Non-vitamin K antagonist oral anticoagulants (NOACs) require dose reductions according to patient or clinical factors for patients with atrial fibrillation (AF). In this meta-analysis, we aimed to assess outcomes with reduced-dose NOACs when given as pre-specified in pivotal trials. Methods and results Aggregated data abstracted from Phase III trials comparing NOACs with warfarin in patients with AF were assessed by treatment using risk ratios (RRs) and 95% confidence intervals (CIs) stratified by patient eligibility for NOAC dose reduction. Irrespective of treatments, annualized rates of stroke or systemic embolism and major bleeding were higher in patients eligible for reduced-dose NOACs than in those eligible for full-dose NOACs (2.70% vs. 1.60% and 4.35% vs. 2.87%, respectively). Effects of reduced-dose NOACs compared with warfarin in patients eligible for reduced-dose NOACs on stroke or systemic embolism [RR 0.84 (95% CI 0.69–1.03)] and on major bleeding [RR 0.70 (95% CI 0.50–0.97)] were consistent with those of full-dose NOACs relative to warfarin in those eligible for full-dose NOACs [RR 0.86 (95% CI 0.77–0.96) for stroke or systemic embolism and RR 0.87 (95% CI 0.70–1.08) for major bleeding; interaction P, 0.89 and 0.26, respectively]. In addition, NOACs were associated with reduced risks of haemorrhagic stroke, intracranial haemorrhage, fatal bleeding, and death regardless of patient eligibility for NOAC dose reduction (interaction P > 0.05 for each). Conclusions Patients eligible for reduced-dose NOACs were at elevated risk of thromboembolic and haemorrhagic complications when treated with anticoagulants. NOACs, when appropriately dose-adjusted, had an improved benefit-harm profile compared with warfarin. Our findings highlight the importance of prescribing reduced-dose NOACs for indicated patient populations.