Prevalence and significance of alterations in cardiac structure and function in patients with heart failure and a preserved ejection fraction

<p><b>Background:</b> The purpose of this study was to examine the prevalence of abnormalities in cardiac structure and function present in patients with heart failure and a preserved ejection fraction (HFPEF) and to determine whether these alterations in structure and function were associated with cardiovascular morbidity and mortality.</p> <p><b>Methods and Results:</b> The Irbesartan in HFPEF trial (I-PRESERVE) enrolled 4128 patients; echocardiographic determination of left ventricular (LV) volume, mass, left atrial (LA) size, systolic function, and diastolic function were made at baseline in 745 patients. The primary end point was death or protocol-specific cardiovascular hospitalization. A secondary end point was the composite of heart failure death or heart failure hospitalization. Associations between baseline structure and function and patient outcomes were examined using univariate and multivariable Cox proportional hazard analyses. In this substudy, LV hypertrophy or concentric remodeling was present in 59%, LA enlargement was present in 66%, and diastolic dysfunction was present in 69% of the patients. Multivariable analyses controlling for 7 clinical variables (including log N-terminal pro-B–type natriuretic peptide) indicated that increased LV mass, mass/volume ratio, and LA size were independently associated with an increased risk of both primary and heart failure events (all P<0.05).</p> <p><b>Conclusions:</b> Left ventricular hypertrophy or concentric remodeling, LA enlargement, and diastolic dysfunction were present in the majority of patients with HFPEF. Left ventricular mass and LA size were independently associated with an increased risk of morbidity and mortality. The presence of structural remodeling and diastolic dysfunction may be useful additions to diagnostic criteria and provide important prognostic insights in patients with HFPEF.</p&gt

Human pleural fluid is a potent growth medium for Streptococcus pneumoniae

Empyema is defined by the presence of bacteria and/or pus in pleural effusions. However, the biology of bacteria within human pleural fluid has not been studied. Streptococcus pneumoniae is the most common cause of pediatric and frequent cause of adult empyema. We investigated whether S. pneumoniae can proliferate within human pleural fluid and if growth is affected by the cellular content of the fluid and/or characteristics of pneumococcal surface proteins. Invasive S. pneumoniae isolates (n = 24) and reference strain recovered from human blood or empyema were inoculated (1.5×10⁶CFU/mL) into sterile human malignant pleural fluid samples (n = 11). All S. pneumoniae (n = 25) strains proliferated rapidly, increasing by a median of 3009 (IQR 1063-9846) from baseline at 24hrs in all pleural effusions tested. Proliferation was greater than in commercial pneumococcal culture media and concentrations were maintained for 48hrs without autolysis. A similar magnitude of proliferation was observed in pleural fluid before and after removal of its cellular content, p = 0.728. S. pneumoniae (D39 strain) wild-type, and derivatives (n = 12), each with mutation(s) in a different gene required for full virulence were inoculated into human pleural fluid (n = 8). S. pneumoniae with pneumococcal surface antigen A (ΔpsaA) mutation failed to grow (2207-fold lower than wild-type), p<0.001, however growth was restored with manganese supplementation. Growth of other common respiratory pathogens (n = 14) across pleural fluid samples (n = 7) was variable and inconsistent, with some strains failing to grow. We establish for the first time that pleural fluid is a potent growth medium for S. pneumoniae and proliferation is dependent on the PsaA surface protein and manganese.Natalia D. Popowicz, Sally M. Lansley, Hui M. Cheah, Ian D. Kay, Christine F. Carson, Grant W. Waterer, James C. Paton, Jeremy S. Brown, Y.C. Gary Le

Density Matrix Renormalisation Group Approach to the Massive Schwinger Model

The massive Schwinger model is studied, using a density matrix renormalisation group approach to the staggered lattice Hamiltonian version of the model. Lattice sizes up to 256 sites are calculated, and the estimates in the continuum limit are almost two orders of magnitude more accurate than previous calculations. Coleman's picture of `half-asymptotic' particles at background field theta = pi is confirmed. The predicted phase transition at finite fermion mass (m/g) is accurately located, and demonstrated to belong in the 2D Ising universality class.Comment: 38 pages, 18 figures, submitted to PR

Electronic cigarettes: A position statement from the Thoracic Society of Australia and New Zealand*

The TSANZ develops position statements where insufficient data exist to write formal clinical guidelines. In 2018, the TSANZ addressed the question of potential benefits and health impacts of electronic cigarettes (EC). The working party included groups focused on health impacts, smoking cessation, youth issues and priority populations. The 2018 report on the Public Health Consequences of E-Cigarettes from the United States NASEM was accepted as reflective of evidence to mid-2017. A search for papers subsequently published in peer-reviewed journals was conducted in August 2018. A small number of robust and important papers published until March 2019 were also identified and included. Groups identified studies that extended, modified or contradicted the NASEM report. A total of 3793 papers were identified and reviewed, with summaries and draft position statements developed and presented to TSANZ membership in April 2019. After feedback from members and external reviewers, a collection of position statements was finalized in December 2019. EC have adverse lung effects and harmful effects of long-term use are unknown. EC are unsuitable consumer products for recreational use, part-substitution for smoking or long-term exclusive use by former smokers. Smokers who require support to quit smoking should be directed towards approved medication in conjunction with behavioural support as having the strongest evidence for efficacy and safety. No specific EC product can be recommended as effective and safe for smoking cessation. Smoking cessation claims in relation to EC should be assessed by established regulators

Melaleuca alternifolia (tea tree) oil inhibits germ tube formation by Candida albicans

The effect of tea tree oil (TTO) on the formation of germ tubes by Candida albicans was examined. Two isolates were tested for germ tube formation (GTF) in the presence of TTO concentrations (% v/v) ranging from 0.25% (1/2 minimum inhibitory concentration [MIC]) to 0.004% (1/128 MIC). GTF at 4 h in the presence of 0.004 and 0.008% (both isolates) and 0.016% (one isolate) TTO did not differ significantly (P > 0.05) from controls. At all other concentrations at 4 h, GTF differed significantly from controls (P < 0.01). A further eight isolates were tested for GTF in the presence of 0.031% TTO, and at 4h the mean GTF for all 10 isolates ranged 10.0-68.5%. Two isolates were examined for their ability to form germ tubes after 1 h of pre-exposure to several concentrations of TTO, prior to induction of germ tubes in horse serum. Cells pre-exposed to 0.125 and 0.25% TTO formed significantly fewer germ tubes than control cells at 1 h (P < 0.05), but only those cells pre-exposed to 0.25% differed significantly from control cells at later time points (P < 0.01). GTF by C. albicans is affected by the presence of, or pre-exposure to, sub-inhibitory concentrations of TTO. This may have therapeutic implications

Antimicrobial activity of the essential oil of Melaleuca alternifolia

Melaleuca alternifolia has been used for medical purposes since Australia was colonized in 1788. Melaleuca alternifolia is commonly called tea tree, although this vernacular name is also given to many other species in the Leptospermum and Melaleuca genera. A small tree, it grows up to 5 m in height, has papery bark and narrow, tapered leaves up to 20 mm in length and flowers in summer. Melaleuca alternifolia is unique to Australia and its natural habitat is a relatively small area around the Clarence and Richmond rivers in the north‐east coastal area of New South Wales where the terrain is generally low lying and swampy. The essential oil of M. alternifolia, or tea tree oil. has enjoyed increased medicinal use in recent years. It is a pale yellow viscous liquid with a distinctive pungent odour and is composed of a complex mixture of monoterpenes, 1‐terpinen‐4‐ol, cineole and other hydrocarbons (Peña 1962)

Safety, efficacy and provenance of tea tree (Melaleuca alternifolia) oil

The identity, sources and composition of tea tree (Melaleuca alternifolia) oil are discussed, and earlier errors in the literature indicated. Reports of both therapeutic and allergenic effects are reviewed