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The Cap- proximal secondary structures of the 5′UTRs of parainfluenza virus 5 mRNAs specify differential sensitivity to type I interferon and IFIT1
Get PDFParainfluenza virus 5 (PIV5) is a paramyxovirus that has been isolated from numerous mammalian hosts and is notable for its ability to cause persistent infections. Although PIV5-infected cells are resistant to IFN due to the ability of the V protein to target STAT1 for degradation, PIV5 shows residual IFN sensitivity when infecting cells that have already been exposed to IFN. We have previously reported that the human IFN-stimulated gene with the greatest inhibitory effect on PIV5 is IFIT1. IFIT1 inhibits the translation of incompletely methylated mRNAs (Cap0) but not those 2′-O-methylated at the first transcribed nucleotide (Cap1). All Mononegavirales are thought to generate Cap1 mRNA, so the sensitivity of PIV5 to IFIT1 is surprising. Here, we show that PIV5 generates Cap0 mRNA but not Cap1 mRNA, thus explaining its sensitivity to IFIT1. Furthermore, the sensitivity of different PIV5 genes to IFIT1-mediated translation inhibition varies. In the absence of complete Cap methylation, we show that the presence or absence of 5′-terminal RNA hairpin structures in the 5′UTRs of PIV5 genes determines the extent to which they are sensitive to IFIT1. Notably, the genes involved in RNA synthesis are relatively resistant to IFIT1 inhibition. This presents a potential mechanism by which IFIT1 can regulate the outcome of PIV5 infection in response to IFN and may be important in allowing the virus to establish prolonged/persistent infections
Streptococcus pneumoniae serotype 33H: a novel serotype with frameshift mutations in the acetyltransferase gene wciG
Get PDFBackground
Streptococcus pneumoniae (the pneumococcus) is a leading cause of community-acquired pneumonia. Pneumococci are categorised into serotypes, based on the type of capsular polysaccharide produced, which has important implications for virulence, vaccine impact and global surveillance. Recently, we identified a novel serotype, which we named 33G, that is comprised of an O-acetylated hexasaccharide repeat unit. In this study, we report and describe variants of 33G, designated 33G-like, which we isolated from the nasopharynx of two adults hospitalised with pneumonia in Mongolia.
Methods
Serological comparison of 33G and 33G-like pneumococci were conducted by Quellung serotyping. Genetic analysis of the capsular polysaccharide loci was performed using whole genome sequencing. Polysaccharide composition was determined using 1H nuclear magnetic resonance.
Results
By Quellung serotyping, 33G pneumococci type as both 10B and 33B whereas 33G-like pneumococci type as both 10B and 33F. Genomic analysis of the capsular polysaccharide locus revealed 33G-like loci are identical to 33G, except for frameshift mutations in the wciG gene which encodes an acetyltransferase responsible for the O-acetylation of beta-galactofuranose (β-Galf) in the capsular polysaccharide repeat unit. We constructed an artificial 33G-like by deleting wciG in a 33G strain and confirmed this gene was responsible for the serological differences between 33G and 33G-like pneumococci. Lastly, 1H nuclear magnetic resonance confirmed the O-acetylation present in the 33G polysaccharide is absent in the 33G-like polysaccharide.
Conclusions
Here, we have provided serological, genetic and biochemical evidence that the 33G-like capsule differs to 33G and all other pneumococcal serotypes, meeting the requirements to be designated as a new serotype, which we have named 33H
Flecainide acetate inhalation solution for cardioversion of recent-onset, symptomatic atrial fibrillation: results of the phase 3 RESTORE-1 trial
Get PDFAims
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia. New treatments are needed to cardiovert recent-onset paroxysmal AF quickly and safely. RESTORE-1 was a multicentre, randomized, double-blind, placebo-controlled trial of a 120 mg orally inhaled solution of flecainide acetate (FlecIH-103) for cardioversion of symptomatic, recent-onset (≤48 h) paroxysmal AF. The study aim was to evaluate the efficacy and safety of FlecIH-103 administered via oral inhalation.
Methods and results
Patients experiencing a recent-onset paroxysmal AF episode were randomized to receive a single dose of FlecIH-103 or placebo delivered over two 3.5 min inhalation periods, while patients were monitored using 12-lead electrocardiograms and Holter. The trial was stopped prematurely after treating 55 patients, due to lower-than-expected conversion rates and plasma levels. Mean age was 59.6 years, 31.5% of patients were female, and 59.2% were having their first AF episode. Conversion rate was 30.8% (95% confidence interval: 14.7–43.8) for the active group (n = 39) and 0.0% for the placebo group (n = 12) (P = 0.04). Median time to conversion was 12.8 min (IQR: 17.2). In the active group, the mean flecainide plasma level was 198 ng/mL (SD: 156), which is ∼50% lower than in the previous studies. The most common adverse events (AEs) were dysgeusia, dyspnoea, and cough. All AEs were short-lasting and of mild or moderate intensity.
Conclusion
Despite early termination of the trial, FlecIH-103 was significantly more effective than placebo in cardioverting AF. Safety data did not show any serious AEs. Further studies of FlecIH-103 are needed to optimize the combination of drug formulation and inhalation delivery platform.
Clinical trial registration
URL: https://clinicaltrials.gov, unique identifier: NCT0503935
Cardiovascular and Renal Treatment in Heart Failure Patients With Hyperkalemia or High Risk of Hyperkalemia: Rationale and Design of the CARE-HK in HF Registry
Get PDFBACKGROUND: Despite guideline recommendations, many patients with heart failure (HF) do not receive target dosages of renin-angiotensin-aldosterone system inhibitors (RAASis) in clinical practice due, in part, to concerns about hyperkalemia (HK). METHODS AND RESULTS: This noninterventional, multinational, multicenter registry (NCT04864795; 111 sites in Europe and the USA) enrolled 2558 eligible adults with chronic HF (mostly with reduced ejection fraction [HFrEF]). Eligibility criteria included use of angiotensin-converting-enzyme inhibitor/angiotensin-II receptor blocker/angiotensin-receptor-neprilysin inhibitor, being a candidate for or treatment with a mineralocorticoid receptor antagonist, and increased risk of HK (eg, current serum potassium > 5.0 mmol/L), history of HK in the previous 24 months, or estimated glomerular filtration rate < 45 mL/min/1.73 m2). Information on RAASi and other guideline-recommended therapies was collected retrospectively and prospectively (≥ 6 months). Patients were followed according to local clinical practice, without study-specific visits or interventions. The main objectives were to characterize RAASi treatment patterns compared with guideline recommendations, describe RAASi modifications following episodes of HK, and describe RAASi treatment in patients treated with patiromer. Baseline characteristics for the first 1000 patients are presented. CONCLUSIONS: CARE-HK is a multinational prospective HF registry designed to report on the management and outcomes of patients with HF at high risk for HK in routine clinical practice
What causes lymphopenia in primary lymphatic anomalies? Implications for understanding lymphocyte homeostasis
No full textProposed framework for triage of putative germline variants detected via tumour genomic testing in UK oncology practice
Get PDFIn the UK, most patients receive publicly funded medical care through the National Health Service (NHS), which funds tumour and/or germline testing for eligible patients with cancer to inform clinical management.
Testing on tumour-derived DNA may identify putative heritable variants, with implications for the proband and their wider family, but is not a reliable substitute for germline genetic testing when hereditary cancer predisposition is suspected.
The likelihood that a variant identified through tumour testing is of germline origin depends on multiple clinical and technical factors. Certain genotypes significantly influence a patient’s cancer risk, and intervention in those carriers may facilitate cancer prevention or early detection, while other genotypes are associated with lower cancer risk, and associated intervention in such cases have limited clinical utility.
We convened a national meeting of clinical cancer genetics and scientific leads to rationalise germline follow-up testing of variants identified through tumour-based testing. After contrasting potential approaches, implementation of an NHS-contextualised ‘intermediate conservative’ approach was agreed and refined by the authors, with the final pathway recirculated to the UK clinical and scientific community for consensus agreement and publication.
We outline relevant patient, genetic and technical considerations informing likely origin of variants, a review of current relevant guidance and NHS laboratory practices and a workflow for laboratory and clinical teams to triage tumour-detected variants requiring onward germline follow-up. This approach aims to direct limited resources towards identifying germline variants associated with the greatest potential clinical impact, with a view to supporting more efficient and equitable delivery of genomic medicine in oncology
Is maternal SARS-CoV-2 infection in the first trimester associated with congenital heart defects?
Get PDFEmerging evidence suggests a potential link between maternal SARS-CoV-2 infection during early pregnancy and the development of congenital heart defects (CHD) in offspring. Although vertical transmission of SARS-CoV-2 is rare, the virus has been associated with placental complications and increased maternal morbidity. Recent studies from China report increased rates of CHD and anomalies such as situs inversus when infection occurs during gestational weeks 4–6, a critical window for cardiac development. Additional reports from different parts of the world also highlight post-pandemic increases in specific cardiac anomalies, including ventricular septal defects (VSDs). Multiple mechanisms may underlie these associations. SARS-CoV-2 can induce placental inflammation, compromise the cytotrophoblast barrier, and impair nutrient and gas exchange, potentially leading to fetal hypoxia and disrupted morphogenic signalling. Furthermore, maternal inflammation and elevated cytokines, along with viral effects on ACE2-expressing fetal cardiac progenitors, could further affect proliferation, differentiation, and apoptosis during cardiac development. Co-infections, hormone disruption, and maternal stress could also contribute. There is an urgent need for longitudinal studies with comprehensive maternal-fetal data, including infection timing, vaccine status, and biological sampling. These will be essential to delineate the multifactorial impacts of maternal infection on fetal cardiac development and long-term outcomes. Special focus should be placed on infections during early pregnancy (weeks 4–7), the period of cardiac septation and left-right asymmetry establishment, to determine causality and inform prevention strategies
Letter to the editor: “Classification of open tibia fractures: the rationale for a new classification system”
Get PDFUse of Sirolimus, an mTOR Inhibitor, to Treat Sarcoidosis in Multiple Systems
Get PDFSarcoidosis is a heterogenous, multi-systemic granulomatous disease with highly variable incidence (5–40/100,000) and a disproportionate mortality burden in those presented with pulmonary fibrosis or cardiac involvement. Yet, current management strategies are symptom-targeting, not always effective and come with significant side effects. Preclinical murine models of sarcoidosis have shown that aberrant mTORC1 activation promotes macrophage-driven inflammation and disrupts autophagic clearance, sustaining granuloma formation. Sirolimus, a selective mTORC1 inhibitor, restores autophagy and macrophage function, offering a targeted therapeutic approach. Herein, we present the first comprehensive review of all known clinical cases of sirolimus use in different forms of sarcoidosis. All studies reviewed suggest that sirolimus may be an effective, yet safe, mechanism-targeting therapy for patients with sarcoidosis not responding to conventional pharmacological interventions
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