Prognostic accuracy of age-adapted SOFA, SIRS, PELOD-2, and qSOFA for in-hospital mortality among children with suspected infection admitted to the intensive care unit

PURPOSE:The Sepsis-3 consensus task force defined sepsis as life-threatening organ dysfunction caused by dysregulated host response to infection. However, the clinical criteria for this definition were neither designed for nor validated in children. We validated the performance of SIRS, age-adapted SOFA, quick SOFA and PELOD-2 scores as predictors of outcome in children. METHODS:We performed a multicentre binational cohort study of patients < 18 years admitted with infection to ICUs in Australia and New Zealand. The primary outcome was ICU mortality. SIRS, age-adapted SOFA, quick SOFA and PELOD-2 scores were compared using crude and adjusted area under the receiver operating characteristic curve (AUROC) analysis. RESULTS:Of 2594 paediatric ICU admissions due to infection, 151 (5.8%) children died, and 949/2594 (36.6%) patients died or experienced an ICU length of stay ≥ 3 days. A ≥ 2-point increase in the individual score was associated with a crude mortality increase from 3.1 to 6.8% for SIRS, from 1.9 to 7.6% for age-adapted SOFA, from 1.7 to 7.3% for PELOD-2, and from 3.9 to 8.1% for qSOFA (p < 0.001). The discrimination of outcomes was significantly higher for SOFA (adjusted AUROC 0.829; 0.791-0.868) and PELOD-2 (0.816; 0.777-0.854) than for qSOFA (0.739; 0.695-0.784) and SIRS (0.710; 0.664-0.756). CONCLUSIONS:SIRS criteria lack specificity to identify children with infection at substantially higher risk of mortality. We demonstrate that adapting Sepsis-3 to age-specific criteria performs better than Sepsis-2-based criteria. Our findings support the translation of Sepsis-3 into paediatric-specific sepsis definitions and highlight the importance of robust paediatric organ dysfunction characterization.Luregn J. Schlapbach, Lahn Straney, Rinaldo Bellomo, Graeme MacLaren, David Pilche

Effect of promoter architecture on the cell-to-cell variability in gene expression

According to recent experimental evidence, the architecture of a promoter, defined as the number, strength and regulatory role of the operators that control the promoter, plays a major role in determining the level of cell-to-cell variability in gene expression. These quantitative experiments call for a corresponding modeling effort that addresses the question of how changes in promoter architecture affect noise in gene expression in a systematic rather than case-by-case fashion. In this article, we make such a systematic investigation, based on a simple microscopic model of gene regulation that incorporates stochastic effects. In particular, we show how operator strength and operator multiplicity affect this variability. We examine different modes of transcription factor binding to complex promoters (cooperative, independent, simultaneous) and how each of these affects the level of variability in transcription product from cell-to-cell. We propose that direct comparison between in vivo single-cell experiments and theoretical predictions for the moments of the probability distribution of mRNA number per cell can discriminate between different kinetic models of gene regulation.Comment: 35 pages, 6 figures, Submitte

Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia. METHODS: We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0), we linked the location of the arrest using the dispatch coordinates (longitude and latitude) to Victorian Local Government Areas (LGAs). We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates. RESULTS: Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1%) cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008-2010 to 68.6% in 2010-2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs. CONCLUSION: Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates

The Genome of Nectria haematococca: Contribution of Supernumerary Chromosomes to Gene Expansion

The ascomycetous fungus Nectria haematococca, (asexual name Fusarium solani), is a member of a group of >50 species known as the “Fusarium solani species complex”. Members of this complex have diverse biological properties including the ability to cause disease on >100 genera of plants and opportunistic infections in humans. The current research analyzed the most extensively studied member of this complex, N. haematococca mating population VI (MPVI). Several genes controlling the ability of individual isolates of this species to colonize specific habitats are located on supernumerary chromosomes. Optical mapping revealed that the sequenced isolate has 17 chromosomes ranging from 530 kb to 6.52 Mb and that the physical size of the genome, 54.43 Mb, and the number of predicted genes, 15,707, are among the largest reported for ascomycetes. Two classes of genes have contributed to gene expansion: specific genes that are not found in other fungi including its closest sequenced relative, Fusarium graminearum; and genes that commonly occur as single copies in other fungi but are present as multiple copies in N. haematococca MPVI. Some of these additional genes appear to have resulted from gene duplication events, while others may have been acquired through horizontal gene transfer. The supernumerary nature of three chromosomes, 14, 15, and 17, was confirmed by their absence in pulsed field gel electrophoresis experiments of some isolates and by demonstrating that these isolates lacked chromosome-specific sequences found on the ends of these chromosomes. These supernumerary chromosomes contain more repeat sequences, are enriched in unique and duplicated genes, and have a lower G+C content in comparison to the other chromosomes. Although the origin(s) of the extra genes and the supernumerary chromosomes is not known, the gene expansion and its large genome size are consistent with this species' diverse range of habitats. Furthermore, the presence of unique genes on supernumerary chromosomes might account for individual isolates having different environmental niches

Transcription activation by the siderophore sensor Btr is mediated by ligand-dependent stimulation of promoter clearance

Bacterial transcription factors often function as DNA-binding proteins that selectively activate or repress promoters, although the biochemical mechanisms vary. In most well-understood examples, activators function by either increasing the affinity of RNA polymerase (RNAP) for the target promoter, or by increasing the isomerization of the initial closed complex to the open complex. We report that Bacillus subtilis Btr, a member of the AraC family of activators, functions principally as a ligand-dependent activator of promoter clearance. In the presence of its co-activator, the siderophore bacillibactin (BB), the Btr:BB complex enhances productive transcription, while having only modest effects on either RNAP promoter association or the production of abortive transcripts. Btr binds to two direct repeat sequences adjacent to the −35 region; recognition of the downstream motif is most important for establishing a productive interaction between the Btr:BB complex and RNAP. The resulting Btr:BB dependent increase in transcription enables the production of the ferric-BB importer to be activated by the presence of its cognate substrate

Year in review in Intensive Care Medicine 2010: III. ARDS and ALI, mechanical ventilation, noninvasive ventilation, weaning, endotracheal intubation, lung ultrasound and paediatrics

SCOPUS: re.jinfo:eu-repo/semantics/publishe

Measuring efficiency in Australian and New Zealand paediatric intensive care units

Purpose: To develop a measure of paediatric intensive care unit (PICU) efficiency and compare the efficiency of PICUs in Australia and New Zealand. Methods: Separate outcome prediction models for estimating clinical performance and resource usage were constructed using patient data from 20,742 admissions between 2005 and 2007. A standardised mortality ratio was calculated using a recalibrated Paediatric Index of Mortality 2 model. A random effects length of stay (LoS) prediction model was used to provide an indicator of unit-level variation in resource use. A modified Rapoport-Teres plot of risk-adjusted mortality versus unit mean LoS provided a visual representation of efficiency. To account for potential differences in admission threshold, the calculation of performance measures was repeated on patients receiving mechanical respiratory support and compared to those estimated for all patients. Results: The modified plot provides a useful tool for visualising ICU efficiency. Two units were identified as potentially inefficient with higher SMR and risk-adjusted mean LoS at the 95% level. One unit had a significantly lower SMR and significantly higher risk-adjusted mean LoS. The measures for both SMR and risk-adjusted mean LoS showed good agreement between all patients and those who received mechanical respiratory support. Conclusion: There is significant variation in efficiency among PICUs in Australia and New Zealand. Two units were designated as inefficient and one unit was considered to be effective at the expense of high resource use. Application of these methods may help to identify ineffi-ciencies in units located in other countries or regions