Structural Insights into the Unique Modes of Relaxin-Binding and Tethered-Agonist Mediated Activation of RXFP1 and RXFP2.

Our poor understanding of the mechanism by which the peptide-hormone H2 relaxin activates its G protein coupled receptor, RXFP1 and the related receptor RXFP2, has hindered progress in its therapeutic development. Both receptors possess large ectodomains, which bind H2 relaxin, and contain an N-terminal LDLa module that is essential for receptor signaling and postulated to be a tethered agonist. Here, we show that a conserved motif (GDxxGWxxxF), C-terminal to the LDLa module, is critical for receptor activity. Importantly, this motif adopts different structures in RXFP1 and RXFP2, suggesting distinct activation mechanisms. For RXFP1, the motif is flexible, weakly associates with the LDLa module, and requires H2 relaxin binding to stabilize an active conformation. Conversely, the GDxxGWxxxF motif in RXFP2 is more closely associated with the LDLa module, forming an essential binding interface for H2 relaxin. These differences in the activation mechanism will aid drug development targeting these receptors.

Glycaemic variability and its association with enteral and parenteral nutrition in critically ill ventilated patients.

BACKGROUND & AIMS: Extremes of dysglycaemia as well as glycaemic variability are associated with excess mortality in critically ill patients. Glycaemic variability is an increasingly important measure of glucose control in the intensive care unit (ICU) due to this association; however, there is limited data pertaining to the relationship between exogenous glucose from nutrition and glycaemic variability and clinical outcomes. The primary aim of this study was to determine if glycaemic variability is associated with an increase in mortality. Secondary objectives were to investigate any factors affecting glycaemic variability, and to characterise the role nutrition, particularly carbohydrate, plays as a contributing factor to glycaemic variability and other clinical outcomes (duration of ventilation and ICU length of stay). METHODS: Data on patients in a combined medical/surgical tertiary Australian Intensive Care Unit (ICU), ventilated for >24 h and exclusively fed by artificial nutrition support was extracted from a clinical database of prospectively collected information over an 18 month period. Glycaemic variability was defined as the coefficient of variation (GV; standard deviation/mean of blood glucose levels x 100). Statistical analysis was performed using logistic regression, zero-truncated negative binomial and linear regression as appropriate to the distribution of the outcome variable using R software. RESULTS: Data on up to 759 subjects was available. The average age of the study cohort was 56.9 years with a mean (standard deviation) APACHE III score of 72 (28). 66% of the study subjects were male. Glycaemic variability was associated with an increase in mortality (odds ratio 1.02; 95% CI: 1.00-1.04, p = 0.03). Factors associated with glycaemic variability included Acute Physiology and Chronic Health Evaluation III score (0.09, 0.06-0.11, p < 0.001), being male (-1.67, -2.97 to -0.38), p = 0.01) and mean units of insulin per day (0.08, 0.06-0.09, p < 0.001). There was no effect of any nutritional factor on glycaemic variability. Further exploratory analyses though showed that for those patients who required insulin during ICU admission, increased insulin dose was associated with increasing carbohydrate (incidence rate ratio (IRR) 1.003, 1.001-1.005, p = 0.001). Mean daily carbohydrate provision (grams) was associated with an increase in ventilation hours (IRR, 95% CI: 1.009, 1.008-1.009, p < 0.001) and length of intensive care unit stay (IRR, 95% CI: 1.007, 1.006-1.008, p < 0.001). CONCLUSION: This study confirms that GV was associated with excess mortality. Furthermore, administration of increasing doses of insulin was associated with increased GV. Increased carbohydrate intake was associated with an increased insulin requirement, as well as increased duration of mechanical ventilation and ICU length of stay. These findings provide important context for further prospective trials investigating the effect of carbohydrate provision in mechanically ventilated critically ill patients requiring artificial nutritional support.

Improving Physical Therapy Pain Care, Quality, and Cost Through Effectiveness-Implementation Research.

The variability and delay in utilizing evidence in clinical practice are barriers to improving care, quality, and cost in health care, as charged by the "triple aim" framework. Scientific research provides an avenue not only to further the field of pain research, but also to study and change the patterns and processes that drive systemic and individual clinical practices. Implementation science is an emerging field that can be integrated with more traditional effectiveness research to accomplish a combination of aims within the same study. This type of concurrent study of effectiveness and implementation is known as a hybrid design and can be used to improve behavioral or operational practice patterns as well as to collect evidence of clinical effectiveness. Recently, the National Pain Strategy put forth recommendations to improve the care of patients with pain through research and practice. Hybrid designs align well with recent efforts that emphasize value-based, patient-centered health care evolving and described in the National Pain Strategy. The purposes of this perspective are to describe implementation science and hybrid studies and to put forth opportunities to utilize this research to advance the care of patients with pain in the United States.

Biochar and compost amendments enhance copper immobilisation and support plant growth in contaminated soils.

Contamination of soil with trace elements, such as Cu, is an important risk management issue. A pot experiment was conducted to determine the effects of three biochars and compost on plant growth and the immobilisation of Cu in a contaminated soil from a site formerly used for wood preservation. To assess Cu mobility, amended soils were analysed using leaching tests pre- and post-incubation, and post-growth. Amended and unamended soils were planted with sunflower, and the resulting plant material was assessed for yield and Cu concentration. All amendments significantly reduced leachable Cu compared to the unamended soil, however, the greatest reductions in leachable Cu were associated with the higher biochar application rate. The greatest improvements in plant yields were obtained with the higher application rate of biochar in combination with compost. The results suggest joint biochar and compost amendment reduces Cu mobility and can support biomass production on Cu-contaminated soils.

Effect of a 2-tier rapid response system on patient outcome and staff satisfaction.

BACKGROUND: Rapid response systems (RRS) have been recommended as a strategy to prevent and treat deterioration in acute care patients. Questions regarding the most effective characteristics of RRS and strategies for implementing these systems remain. AIMS: The aims of this study were to (i) describe the structures and processes used to implement a 2-tier RRS, (ii) determine the comparative prevalence of deteriorating patients and incidence of unplanned intensive care unit (ICU) admission and cardiac arrest prior to and after implementation of the RRS, and (iii) determine clinician satisfaction with the RRS. METHOD: A quasi-experimental pre-test, post-test design was used to assess patient related outcomes and clinician satisfaction prior to and after implementation of a 2-tier RRS in a tertiary metropolitan hospital. Primary components of the RRS included an ICU Outreach Nurse and a Rapid Response Team. Prevalence of deteriorating patients was assessed through a point prevalence assessment and chart audit. Incidence of unplanned admission to ICU and cardiac arrests were accessed from routine hospital databases. Clinician satisfaction was measured through surveys. RESULTS: Prevalence of patients who met medical emergency call criteria without current treatment reduced from 3% prior to RRS implementation to 1% after implementation; a similar reduction from 9% to 3% was identified on chart review. The number of unplanned admissions to ICU increased slightly from 17.4/month prior to RRS implementation to 18.1/month after implementation (p=0.45) while cardiac arrests reduced slightly from 7.5/month to 5.6/month (p=0.22) but neither of these changes were statistically significant. Staff satisfaction with the RRS was generally high. CONCLUSION: The 2-tier RRS was accessed by staff to assist with care of deteriorating patients in a large, tertiary hospital. High levels of satisfaction have been reported by clinical staff.

Genome-wide methylation analyses of primary human leukocyte subsets identifies functionally important cell-type-specific hypomethylated regions.

DNA methylation is an important mechanism by which gene transcription and hence cellular function are regulated. Here, we provide detailed functional genome-wide methylome maps of 5 primary peripheral blood leukocyte subsets including T cells, B cells, monocytes/macrophages, and neutrophils obtained from healthy individuals. A comparison of these methylomes revealed highly specific cell-lineage and cell-subset methylation profiles. DNA hypomethylation is known to be permissive for gene expression and we identified cell-subset-specific hypomethylated regions (HMRs) that strongly correlate with gene transcription levels suggesting these HMRs may regulate corresponding cell functions. Single-nucleotide polymorphisms associated with immune-mediated disease in genome-wide association studies preferentially localized to these cell-specific regulatory HMRs, offering insight into pathogenesis by highlighting cell subsets in which specific epigenetic changes may drive disease. Our data provide a valuable reference tool for researchers aiming to investigate the role of DNA methylation in regulating primary leukocyte function in health and immune-mediated disease.

A multicenter randomized trial of atorvastatin therapy in intensive care patients with severe sepsis.

RATIONALE: Observational studies link statin therapy with improved outcomes in patients with severe sepsis. OBJECTIVES: To test whether atorvastatin therapy affects biologic and clinical outcomes in critically ill patients with severe sepsis. METHODS: Phase II, multicenter, prospective, randomized, double-blind, placebo-controlled trial stratified by site and prior statin use. A cohort of 250 critically ill patients (123 statins, 127 placebo) with severe sepsis were administrated either atorvastatin (20 mg daily) or matched placebo. MEASUREMENTS AND MAIN RESULTS: There was no difference in IL-6 concentrations (primary end point) between the atorvastatin and placebo groups (P = 0.76) and no interaction between treatment group and time to suggest that the groups behaved differently over time (P = 0.26). Baseline plasma IL-6 was lower among previous statin users (129 [87-191] vs. 244 [187-317] pg/ml; P = 0.01). There was no difference in length of stay, change in Sequential Organ Failure Assessment scores or mortality at intensive care unit discharge, hospital discharge, 28- or 90-day (15% vs. 19%), or adverse effects between the two groups. Cholesterol was lower in patients treated with atorvastatin (2.4 [0.07] vs. 2.6 [0.06] mmol/L; P = 0.006). In the predefined group of 77 prior statin users, those randomized to placebo had a greater 28-day mortality (28% vs. 5%; P = 0.01) compared with those who received atorvastatin. The difference was not statistically significant at 90 days (28% vs. 11%; P = 0.06). CONCLUSIONS: Atorvastatin therapy in severe sepsis did not affect IL-6 levels. Prior statin use was associated with a lower baseline IL-6 concentration and continuation of atorvastatin in this cohort was associated with improved survival. Clinical trial registered with the Australian New Zealand Clinical Trials Registry (ACTRN 12607000028404).

A combined functional annotation score for non-synonymous variants.

AIMS: Next-generation sequencing has opened the possibility of large-scale sequence-based disease association studies. A major challenge in interpreting whole-exome data is predicting which of the discovered variants are deleterious or neutral. To address this question in silico, we have developed a score called Combined Annotation scoRing toOL (CAROL), which combines information from 2 bioinformatics tools: PolyPhen-2 and SIFT, in order to improve the prediction of the effect of non-synonymous coding variants. METHODS: We used a weighted Z method that combines the probabilistic scores of PolyPhen-2 and SIFT. We defined 2 dataset pairs to train and test CAROL using information from the dbSNP: 'HGMD-PUBLIC' and 1000 Genomes Project databases. The training pair comprises a total of 980 positive control (disease-causing) and 4,845 negative control (non-disease-causing) variants. The test pair consists of 1,959 positive and 9,691 negative controls. RESULTS: CAROL has higher predictive power and accuracy for the effect of non-synonymous variants than each individual annotation tool (PolyPhen-2 and SIFT) and benefits from higher coverage. CONCLUSION: The combination of annotation tools can help improve automated prediction of whole-genome/exome non-synonymous variant functional consequences.

Prediction of hospital outcome in septic shock: a prospective comparison of tissue Doppler and cardiac biomarkers.

INTRODUCTION: Diastolic dysfunction as demonstrated by tissue Doppler imaging (TDI), particularly E/e' (peak early diastolic transmitral/peak early diastolic mitral annular velocity) is common in critical illness. In septic shock, the prognostic value of TDI is undefined. This study sought to evaluate and compare the prognostic significance of TDI and cardiac biomarkers (B-type natriuretic peptide (BNP); N-terminal proBNP (NTproBNP); troponin T (TnT)) in septic shock. The contribution of fluid management and diastolic dysfunction to elevation of BNP was also evaluated. METHODS: Twenty-one consecutive adult patients from a multidisciplinary intensive care unit underwent transthoracic echocardiography and blood collection within 72 hours of developing septic shock. RESULTS: Mean +/- SD APACHE III score was 80.1 +/- 23.8. Hospital mortality was 29%. E/e' was significantly higher in hospital non-survivors (15.32 +/- 2.74, survivors 9.05 +/- 2.75; P = 0.0002). Area under ROC curves were E/e' 0.94, TnT 0.86, BNP 0.78 and NTproBNP 0.67. An E/e' threshold of 14.5 offered 100% sensitivity and 83% specificity. Adjustment for APACHE III, cardiac disease, fluid balance and grade of diastolic function, demonstrated E/e' as an independent predictor of hospital mortality (P = 0.019). Multiple linear regression incorporating APACHE III, gender, cardiac disease, fluid balance, noradrenaline dose, C reactive protein, ejection fraction and diastolic dysfunction yielded APACHE III (P = 0.033), fluid balance (P = 0.001) and diastolic dysfunction (P = 0.009) as independent predictors of BNP concentration. CONCLUSIONS: E/e' is an independent predictor of hospital survival in septic shock. It offers better discrimination between survivors and non-survivors than cardiac biomarkers. Fluid balance and diastolic dysfunction were independent predictors of BNP concentration in septic shock.

Field-based evaluation tool for riparian buffer zones in agricultural catchments.

Riparian buffer zones can improve water quality and enhance habitat, but a comprehensive yet rapid method that can assist the resource manager in assessing the effectiveness of buffers is not available. The aim of this paper is to describe and illustrate the use of a newly developed field-based evaluation tool for riparian buffer zones in agricultural catchments. The Buffer Zone Inventory and Evaluation Form (BZIEF) incorporates criteria-based scoring systems developed from literature review, subsequent peer-review, and then a pilot field study. Use of the BZIEF is demonstrated by comparing buffer zones in three catchments established for water quality and habitat improvement under the Water Fringe Option agrienvironment scheme in England in order to assess whether the buffers were likely to provide environmental enhancement. Results among the three catchments were generally similar; buffer zones scored highly for their abundant vegetation cover, lack of erosion, stream habitat quality, and sufficient width. Furthermore, previous grassland or arable land use did not substantially affect buffer zone ratings. However, the BZIEF indicated that inappropriate soil characteristics in one catchment were likely to constrain buffer zone effectiveness for improving water quality. In another catchment, poor riparian vegetation diversity and structure may yield ineffective habitat enhancement, according to the BZIEF. It was concluded that the BZIEF might be a useful tool for buffer zone comparison and monitoring, even though more work is needed to test and validate the method. For example, the BZIEF could be used to target appropriate locations for buffer zones and is flexible, so could be adapted for different policies, objectives and regions.