24 research outputs found

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Lost in a Crowd: Observations of Single DNA Knots and Single Mammalian Cells

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    This thesis is dedicated to my parents, to my mentors, Steve Quake and Mel Simon, to the other people in lab, especially the postdocs, who, really, taught me all the nuts and bolts of putting together an experiment and making it work, and to all the other friends along the way who made the journey so much fun. iv Acknowledgements I worked together with Heun Jin Lee on the knots project. He put all the instrumentation in place to perform the experiments, and throughout the experiment taught me to think and work systematically and effectively. I could have avoided many pitfalls and delays in that and subsequent experiments, had I followed his advice more diligently. Alex Groisman and Keith Matthews did some preliminary work on the knots project. In particular, Alex suggested the use of high-molecular weight PEG to increase viscosity without changing refraction index and also provided the initial oxygen scavenging recipe; the idea to use servo motors to control the optical elements was Keith’s. Theoretical predictions of knot sizes for the 71 knot, not published elsewhere, were kindly provided by Pietro Pieranski. He, Andrjez Stasiak, Doug Smith, Mei Wang, and Julius Su provided other helpful suggestions in the knots project. Members of the Quake group who taught me the art and craft of microfluidics included Emil Kartalov and Carl Hansen. The use of constrictions to control shear stress was suggested by Mike Diehl. All the biology for the signaling project was done in Mel Simon’s lab, and I’d like t

    Lost in a Crowd: Observations of Single DNA Knots and Single Mammalian Cells

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    The overarching theme for the two main experiments presented here is that standard biochemical and cell biological techniques, which need fairly large samples and hence average over large numbers of things, be they molecules or cells, tend to smear out interesting phenomena that occur to a small fraction of those things. Averaging also collapses the entire population distribution into one single value, and furthermore prevents tracking properties of individuals over the lifetime of the experiment. The first project described here involves mechanically tying knots into linear DNA molecules stretched out between optically trapped beads. Without mechanical intervention, the molecules we used contained knots only rarely, and those knots are expected to involve small portions of the DNA contour and hence give only small perturbations to the overall polymer dynamics. By tying and observing them singly, we were able to show that, while knots collapse and tighten under tension, even the most complex ones we tied retained mobility to quite a surprising degree. The observed knot sizes and diffusivities correlated well with theoretical predictions for knots in ideal ropes of finite thickness, indicating that even under high tension the different parts of the molecular knots are kept away from each other because of electrostatic repulsion. The differences between knots of different topologies, both in size and speed, open up the possibility that, with further refinement, this approach may allow us to observe the stepwise actions of single topoisomerases in chemically undoing complex knots. The second project was to develop a microfluidic system to perform many signaling experiments on cells simultaneously within a single field-of-view of a microscope. Single cell sensitivity has been pivotal both in verifying data quality and in understanding cell-to-cell variabilities in signaling strengths. In the course of these two projects I also had a few side ideas which, sadly, I wasn’t able to develop to the degree that I would have liked. I've included them here as minor digressions, in the hopes that someone will see them and find them useful

    Suppression of LPS-Induced TNF-α Production in Macrophages by cAMP Is Mediated by PKA-AKAP95-p105

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    The activation of macrophages through Toll-like receptor (TLR) pathways leads to the production of a broad array of cytokines and mediators that coordinate the immune response. The inflammatory potential of this response can be reduced by compounds, such as prostaglandin E_2, that induce the production of cyclic adenosine monophosphate (cAMP). Through experiments with cAMP analogs and multigene RNA interference (RNAi), we showed that key anti-inflammatory effects of cAMP were mediated specifically by cAMP-dependent protein kinase (PKA). Selective inhibitors of PKA anchoring, time-lapse microscopy, and RNAi screening suggested that differential mechanisms of PKA action existed. We showed a specific role for A kinase–anchoring protein 95 in suppressing the expression of the gene encoding tumor necrosis factor–, which involved phosphorylation of p105 (also known as Nfkb1) by PKA at a site adjacent to the region targeted by inhibitor of nuclear factor B kinases. These data suggest that crosstalk between the TLR4 and cAMP pathways in macrophages can be coordinated through PKA-dependent scaffolds that localize specific pools of the kinase to distinct substrates

    Mitochondrial dysfunction remodels one-carbon metabolism in human cells

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    Mitochondrial dysfunction is associated with a spectrum of human disorders, ranging from rare, inborn errors of metabolism to common, age-associated diseases such as neurodegeneration. How these lesions give rise to diverse pathology is not well understood, partly because their proximal consequences have not been well-studied in mammalian cells. Here we provide two lines of evidence that mitochondrial respiratory chain dysfunction leads to alterations in one-carbon metabolism pathways. First, using hypothesis-generating metabolic, proteomic, and transcriptional profiling, followed by confirmatory experiments, we report that mitochondrial DNA depletion leads to an ATF4-mediated increase in serine biosynthesis and transsulfuration. Second, we show that lesioning the respiratory chain impairs mitochondrial production of formate from serine, and that in some cells, respiratory chain inhibition leads to growth defects upon serine withdrawal that are rescuable with purine or formate supplementation. Our work underscores the connection between the respiratory chain and one-carbon metabolism with implications for understanding mitochondrial pathogenesis.National Institutes of Health (U.S.) (Grant R01DK081457

    The complete genome sequence of the \u3ci\u3eArabidopsis\u3c/i\u3e and tomato pathogen \u3ci\u3ePseudomonas syringae\u3c/i\u3e pv. \u3ci\u3etomato\u3c/i\u3e DC3000

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    We report the complete genome sequence of the model bacterial pathogen Pseudomonas syringae pathovar tomato DC3000 (DC3000), which is pathogenic on tomato and Arabidopsis thaliana. The DC3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 ORFs. We identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type III secretion system effector proteins. Many of the virulence genes were members of paralogous families and also were proximal to mobile elements, which collectively comprise7%of the DC3000 genome. The bacterium possesses a large repertoire of transporters for the acquisition of nutrients, particularly sugars, as well as genes implicated in attachment to plant surfaces. Over 12% of the genes are dedicated to regulation, which may reflect the need for rapid adaptation to the diverse environments encountered during epiphytic growth and pathogenesis. Comparative analyses confirmed a high degree of similarity with two sequenced pseudomonads, Pseudomonas putida and Pseudomonas aeruginosa, yet revealed 1,159 genes unique to DC3000, of which 811 lack a known function. Includes published article and additional supporting materials

    Variability in G-Protein-Coupled Signaling Studied with Microfluidic Devices

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    Different cells, even those that are genetically identical, can respond differently to identical stimuli, but the precise source of this variability remains obscure. To study this problem, we built a microfluidic experimental system which can track responses of individual cells across multiple stimulations. We used this system to determine that amplitude variation in G-protein-activated calcium release in RAW264.7 macrophages is generally extrinsic, i.e., they arise from long-lived variations between cells and not from stochastic activation of signaling components. In the case of responses linked to P2Y family purine receptors, we estimate that approximately one-third of the observed variability in calcium release is receptor-specific. We further demonstrate that the signaling apparatus downstream of P2Y6 receptor activation is moderately saturable. These observations will be useful in constructing and constraining single-cell models of G protein-coupled calcium dynamics

    Cross-oncopanel study reveals high sensitivity and accuracy with overall analytical performance depending on genomic regions.

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    Targeted sequencing using oncopanels requires comprehensive assessments of accuracy and detection sensitivity to ensure analytical validity. By employing reference materials characterized by the U.S. Food and Drug Administration-led SEquence Quality Control project phase2 (SEQC2) effort, we perform a cross-platform multi-lab evaluation of eight Pan-Cancer panels to assess best practices for oncopanel sequencing. All panels demonstrate high sensitivity across targeted high-confidence coding regions and variant types for the variants previously verified to have variant allele frequency (VAF) in the 5-20% range. Sensitivity is reduced by utilizing VAF thresholds due to inherent variability in VAF measurements. Enforcing a VAF threshold for reporting has a positive impact on reducing false positive calls. Importantly, the false positive rate is found to be significantly higher outside the high-confidence coding regions, resulting in lower reproducibility. Thus, region restriction and VAF thresholds lead to low relative technical variability in estimating promising biomarkers and tumor mutational burden. This comprehensive study provides actionable guidelines for oncopanel sequencing and clear evidence that supports a simplified approach to assess the analytical performance of oncopanels. It will facilitate the rapid implementation, validation, and quality control of oncopanels in clinical use.All SEQC2 participants freely donated their time, reagents, and computing resources for the completion and analysis of this project. Part of this work was carried out with the support of the Intramural Research Program of the National Institutes of Health (to Mehdi Pirooznia), National Institute of Environmental Health Sciences (to Pierre Bushel), and National Library of Medicine (to Danielle Thierry-Mieg, Jean Thierry-Mieg, and Chunlin Xiao). Leming Shi and Yuanting Zheng were supported by the National Key R&D Project of China (2018YFE0201600), the National Natural Science Foundation of China (31720103909), and Shanghai Municipal Science and Technology Major Project (2017SHZDZX01). Donald J. Johann, Jr. acknowledges the support by FDA BAA grant HHSF223201510172C. Timothy Mercer and Ira Deveson were supported by the National Health and Medical Research Council (NHMRC) of Australia grants APP1108254, APP1114016, and APP1173594 and Cancer Institute NSW Early Career Fellowship 2018/ECF013. This research has also been, in part, financially supported by the MEYS of the CR under the project CEITEC 2020 (LQ1601), by MH CR, grant No. (NV19-03-00091). Part of this work was carried out with the support of research infrastructure EATRIS-CZ, ID number LM2015064, funded by MEYS CR. Boris Tichy and Nikola Tom were supported by research infrastructure EATRIS-CZ, ID number LM2018133 funded by MEYS CR and MEYS CR project CEITEC 2020 (LQ1601).S
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