A randomised controlled trial of an open lung strategy with staircase recruitment, titrated PEEP and targeted low airway pressures in patients with acute respiratory distress syndrome

INTRODUCTION: Tidal volume and plateau pressure minimisation are the standard components of a protective lung ventilation strategy for patients with acute respiratory distress syndrome (ARDS). Open lung strategies, including higher positive end-expiratory pressure (PEEP) and recruitment manoeuvres to date have not proven efficacious. This study examines the effectiveness and safety of a novel open lung strategy, which includes permissive hypercapnia, staircase recruitment manoeuvres (SRM) and low airway pressure with PEEP titration. METHOD: Twenty ARDS patients were randomised to treatment or ARDSnet control ventilation strategies. The treatment group received SRM with decremental PEEP titration and targeted plateau pressure < 30 cm H2O. Gas exchange and lung compliance were measured daily for 7 days and plasma cytokines in the first 24 hours and on days 1, 3, 5 and 7 (mean ± SE). Duration of ventilation, ICU stay and hospital stay (median and interquartile range) and hospital survival were determined. RESULTS: There were significant overall differences between groups when considering plasma IL-8 and TNF-α. For plasma IL-8, the control group was 41% higher than the treatment group over the seven-day period (ratio 1.41 (1.11 to 1.79), P = 0.01), while for TNF-α the control group was 20% higher over the seven-day period (ratio 1.20 (1.01 to 1.42) P = 0.05). PaO2/FIO2 (204 ± 9 versus 165 ± 9 mmHg, P = 0.005) and static lung compliance (49.1 ± 2.9 versus 33.7 ± 2.7 mls/cm H2O, P < 0.001) were higher in the treatment group than the control group over seven days. There was no difference in duration of ventilation (180 (87 to 298) versus 341 (131 to 351) hrs, P = 0.13), duration of ICU stay (9.9 (5.6 to 14.8) versus 16.0 (8.1 to 19.3) days, P = 0.19) and duration of hospital stay (17.9 (13.7 to 34.5) versus 24.7 (20.5 to 39.8) days, P = 0.16) between the treatment and control groups. CONCLUSIONS: This open lung strategy was associated with greater amelioration in some systemic cytokines, improved oxygenation and lung compliance over seven days. A larger trial powered to examine clinically-meaningful outcomes is warranted. TRIAL REGISTRATION: ACTRN12607000465459

The structure of BVU2987 from Bacteroides vulgatus reveals a superfamily of bacterial periplasmic proteins with possible inhibitory function.

Proteins that contain the DUF2874 domain constitute a new Pfam family PF11396. Members of this family have predominantly been identified in microbes found in the human gut and oral cavity. The crystal structure of one member of this family, BVU2987 from Bacteroides vulgatus, has been determined, revealing a β-lactamase inhibitor protein-like structure with a tandem repeat of domains. Sequence analysis and structural comparisons reveal that BVU2987 and other DUF2874 proteins are related to β-lactamase inhibitor protein, PepSY and SmpA_OmlA proteins and hence are likely to function as inhibitory proteins

Structure of the γ-D-glutamyl-L-diamino acid endopeptidase YkfC from Bacillus cereus in complex with L-Ala-γ-D-Glu: insights into substrate recognition by NlpC/P60 cysteine peptidases.

Dipeptidyl-peptidase VI from Bacillus sphaericus and YkfC from Bacillus subtilis have both previously been characterized as highly specific γ-D-glutamyl-L-diamino acid endopeptidases. The crystal structure of a YkfC ortholog from Bacillus cereus (BcYkfC) at 1.8 Å resolution revealed that it contains two N-terminal bacterial SH3 (SH3b) domains in addition to the C-terminal catalytic NlpC/P60 domain that is ubiquitous in the very large family of cell-wall-related cysteine peptidases. A bound reaction product (L-Ala-γ-D-Glu) enabled the identification of conserved sequence and structural signatures for recognition of L-Ala and γ-D-Glu and, therefore, provides a clear framework for understanding the substrate specificity observed in dipeptidyl-peptidase VI, YkfC and other NlpC/P60 domains in general. The first SH3b domain plays an important role in defining substrate specificity by contributing to the formation of the active site, such that only murein peptides with a free N-terminal alanine are allowed. A conserved tyrosine in the SH3b domain of the YkfC subfamily is correlated with the presence of a conserved acidic residue in the NlpC/P60 domain and both residues interact with the free amine group of the alanine. This structural feature allows the definition of a subfamily of NlpC/P60 enzymes with the same N-terminal substrate requirements, including a previously characterized cyanobacterial L-alanine-γ-D-glutamate endopeptidase that contains the two key components (an NlpC/P60 domain attached to an SH3b domain) for assembly of a YkfC-like active site

Protocol and statistical analysis plan for the mega randomised registry trial comparing conservative vs. liberal oxygenation targets in adults with sepsis in the intensive care unit (Mega-ROX Sepsis)

Background: The effect of conservative vs. liberal oxygen therapy on 90-day in-hospital mortality in adults with sepsis receiving unplanned invasive mechanical ventilation in the intensive care unit (ICU) is uncertain. Objective: The objective of this study was to summarise the protocol and statistical analysis plan for the Mega-ROX Sepsis trial. Design, setting, and participants: The Mega-ROX Sepsis trial is an international randomised clinical trial that will be conducted within an overarching 40,000-patient registry-embedded clinical trial comparing conservative and liberal ICU oxygen therapy regimens. We anticipate that between 10,000 and 13,000 patients with sepsis who are receiving unplanned invasive mechanical ventilation in the ICU will be enrolled in this trial. Main outcome measures: The primary outcome is in-hospital all-cause mortality up to 90 days from the date of randomisation. Secondary outcomes include duration of survival, duration of mechanical ventilation, ICU length of stay, hospital length of stay, and the proportion of patients discharged home. Results and conclusions: Mega-ROX Sepsis will compare the effect of conservative vs. liberal oxygen therapy on 90-day in-hospital mortality in adults with sepsis who are receiving unplanned invasive mechanical ventilation in the ICU. The protocol and a prespecified approach to analyses are reported here to mitigate analysis bias

LSST: from Science Drivers to Reference Design and Anticipated Data Products

(Abridged) We describe here the most ambitious survey currently planned in the optical, the Large Synoptic Survey Telescope (LSST). A vast array of science will be enabled by a single wide-deep-fast sky survey, and LSST will have unique survey capability in the faint time domain. The LSST design is driven by four main science themes: probing dark energy and dark matter, taking an inventory of the Solar System, exploring the transient optical sky, and mapping the Milky Way. LSST will be a wide-field ground-based system sited at Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m effective) primary mirror, a 9.6 deg$^2$ field of view, and a 3.2 Gigapixel camera. The standard observing sequence will consist of pairs of 15-second exposures in a given field, with two such visits in each pointing in a given night. With these repeats, the LSST system is capable of imaging about 10,000 square degrees of sky in a single filter in three nights. The typical 5$\sigma$ point-source depth in a single visit in $r$ will be $\sim 24.5$ (AB). The project is in the construction phase and will begin regular survey operations by 2022. The survey area will be contained within 30,000 deg$^2$ with $\delta<+34.5^\circ$, and will be imaged multiple times in six bands, $ugrizy$, covering the wavelength range 320--1050 nm. About 90\% of the observing time will be devoted to a deep-wide-fast survey mode which will uniformly observe a 18,000 deg$^2$ region about 800 times (summed over all six bands) during the anticipated 10 years of operations, and yield a coadded map to $r\sim27.5$. The remaining 10\% of the observing time will be allocated to projects such as a Very Deep and Fast time domain survey. The goal is to make LSST data products, including a relational database of about 32 trillion observations of 40 billion objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures available from https://www.lsst.org/overvie

Expert consensus and recommendations on safety criteria for active mobilization of mechanically ventilated critically ill adults

Introduction: The aim of this study was to develop consensus recommendations on safety parameters for mobilizing adult, mechanically ventilated, intensive care unit (ICU) patients. Methods: A systematic literature review was followed by a meeting of 23 multidisciplinary ICU experts to seek consensus regarding the safe mobilization of mechanically ventilated patients. Results: Safety considerations were summarized in four categories: respiratory, cardiovascular, neurological and other. Consensus was achieved on all criteria for safe mobilization, with the exception being levels of vasoactive agents. Intubation via an endotracheal tube was not a contraindication to early mobilization and a fraction of inspired oxygen less than 0.6 with a percutaneous oxygen saturation more than 90% and a respiratory rate less than 30 breaths/minute were considered safe criteria for in- and out-of-bed mobilization if there were no other contraindications. At an international meeting, 94 multidisciplinary ICU clinicians concurred with the proposed recommendations. Conclusion: Consensus recommendations regarding safety criteria for mobilization of adult, mechanically ventilated patients in the ICU have the potential to guide ICU rehabilitation whilst minimizing the risk of adverse events

Structure of BT_3984, a member of the SusD/RagB family of nutrient-binding molecules

The crystal structure of BT_3984, a SusD-family protein, reveals a TPR N-terminal region providing support for a loop-rich C-terminal subdomain and suggests possible interfaces involved in sus complex formation

Structures of three members of Pfam PF02663 (FmdE) implicated in microbial methanogenesis reveal a conserved α+β core domain and an auxiliary C-terminal treble-clef zinc finger

The first structures from the FmdE Pfam family (PF02663) reveal that some members of this family form tightly intertwined dimers consisting of two domains (N-terminal α+β core and C-terminal zinc-finger domains), whereas others contain only the core domain. The presence of the zinc-finger domain suggests that some members of this family may perform functions associated with transcriptional regulation, protein–protein interaction, RNA binding or metal-ion sensing