29 research outputs found

    NMR structure of Hsp12, a protein induced by and required for dietary restriction-induced lifespan extension in yeast.

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    Dietary restriction (DR) extends lifespan in yeast, worms, flies and mammals, suggesting that it may act via conserved processes. However, the downstream mechanisms by which DR increases lifespan remain unclear. We used a gel based proteomic strategy to identify proteins whose expression was induced by DR in yeast and thus may correlate with longevity. One protein up-regulated by DR was Hsp12, a small heat shock protein induced by various manipulations known to retard ageing. Lifespan extension by growth on 0.5% glucose (DR) was abolished in an hsp12Δ strain, indicating that Hsp12 is essential for the longevity effect of DR. In contrast, deletion of HSP12 had no effect on growth under DR conditions or a variety of environmental stresses, indicating that the effect of Hsp12 on lifespan is not due to increased general stress resistance. Unlike other small heat shock proteins, recombinant Hsp12 displayed negligible in vitro molecular chaperone activity, suggesting that its cellular function does not involve preventing protein aggregation. NMR analysis indicated that Hsp12 is monomeric and intrinsically unfolded in solution, but switches to a 4-helical conformation upon binding to membrane-mimetic SDS micelles. The structure of micelle-bound Hsp12 reported here is consistent with its recently proposed function as a membrane-stabilising 'lipid chaperone'. Taken together, our data suggest that DR-induced Hsp12 expression contributes to lifespan extension, possibly via membrane alterations

    Maximizing Wound Coverage in Full-Thickness Skin Defects: A Randomized-Controlled Trial of Autologous Skin Cell Suspension and Widely Meshed Autograft Versus Standard Autografting

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    BACKGROUND: Traumatic insults, infection, and surgical procedures can leave skin defects that are not amenable to primary closure. Split-thickness skin grafting (STSG) is frequently used to achieve closure of these wounds. Although effective, STSG can be associated with donor site morbidity, compounding the burden of illness in patients undergoing soft tissue reconstruction procedures. With an expansion ratio of 1:80, autologous skin cell suspension (ASCS) has been demonstrated to significantly decrease donor skin requirements compared with traditional STSG in burn injuries. We hypothesized that the clinical performance of ASCS would be similar for soft tissue reconstruction of nonburn wounds. METHODS: A multicenter, within-patient, evaluator-blinded, randomized-controlled trial was conducted of 65 patients with acute, nonthermal, full-thickness skin defects requiring autografting. For each patient, two treatment areas were randomly assigned to concurrently receive a predefined standard-of-care meshed STSG (control) or ASCS + more widely meshed STSG (ASCS+STSG). Coprimary endpoints were noninferiority of ASCS+STSG for complete treatment area closure by Week 8, and superiority for relative reduction in donor skin area. RESULTS: At 8 weeks, complete closure was observed for 58% of control areas compared with 65% of ASCS+STSG areas (p = 0.005), establishing noninferiority of ASCS+STSG. On average, 27.4% less donor skin was required with ASCS+ STSG, establishing superiority over control (p \u3c 0.001). Clinical healing (≥95% reepithelialization) was achieved in 87% and 85% of Control and ASCS+STSG areas, respectively, at 8 weeks. The treatment approaches had similar long-term scarring outcomes and safety profiles, with no unanticipated events and no serious ASCS device-related events. CONCLUSION: ASCS+STSG represents a clinically effective and safe solution to reduce the amount of skin required to achieve definitive closure of full-thickness defects without compromising healing, scarring, or safety outcomes. This can lead to reduced donor site morbidity and potentially decreased cost associated with patient care. Clincaltrials.gov identifier: NCT04091672. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level I

    Multi-omic analysis in injured humans: Patterns align with outcomes and treatment responses

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    Trauma is a leading cause of death and morbidity worldwide. Here, we present the analysis of a longitudinal multi-omic dataset comprising clinical, cytokine, endotheliopathy biomarker, lipidome, metabolome, and proteome data from severely injured humans. A "systemic storm" pattern with release of 1,061 markers, together with a pattern suggestive of the "massive consumption" of 892 constitutive circulating markers, is identified in the acute phase post-trauma. Data integration reveals two human injury response endotypes, which align with clinical trajectory. Prehospital thawed plasma rescues only endotype 2 patients with traumatic brain injury (30-day mortality: 30.3 versus 75.0%; p = 0.0015). Ubiquitin carboxy-terminal hydrolase L1 (UCHL1) was identified as the most predictive circulating biomarker to identify endotype 2-traumatic brain injury (TBI) patients. These response patterns refine the paradigm for human injury, while the datasets provide a resource for the study of critical illness, trauma, and human stress responses

    Robust estimation of bacterial cell count from optical density

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    Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

    Use of Biomarkers in the Evaluation and Treatment of Hypertensive Patients

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    The current definition of hypertension is based on blood pressure values, and blood pressure also drives treatment decisions, is the most important treatment monitoring tool and helps estimating risk of hypertension related organ damage. In an era of precision medicine additional biomarkers are needed in the diagnosis and management of patients with hypertension. In this review we outline the areas in which functional, imaging and circulating biomarkers could help in a more individualised definition of hypertension and associated risk. We will cover biomarkers for diagnosis; of pathophysiology and prediction of hypertension; response to treatment, organ damage; and to monitor treatment. A clear focus is on the vasculature, the heart and the kidneys, whereas we see a need to further develop biomarkers of cerebral function in order to diagnose cognition deficits and monitor changes in cognition in the future to support addressing the growing burden of hypertension associated vascular dementia

    Coordinating Care for Falls via Emergency Responders: A Feasibility Study of a Brief At-Scene Intervention

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    Falls account for a substantial portion of 9-1-1 calls, but few studies have examined the potential for an emergency medical system role in fall prevention. We tested the feasibility and effectiveness of an emergency medical technician (EMT)-delivered, at-scene intervention to link elders calling 9-1-1 for a fall with a multifactorial fall prevention program in their community. The intervention was conducted in a single fire department in King County, Washington and consisted of a brief public health message about the preventability of falls and written fall prevention program information left at scene. Data sources included 9-1-1 reports, telephone interviews with intervention department fallers and sociodemographically comparable fallers from three other fire departments in the same county, and in-person discussions with intervention department EMTs. Interviews elicited faller recall and perceptions of the intervention, EMT perceptions of intervention feasibility, and resultant referrals. Sixteen percent of all 9-1-1 calls during the intervention period were for falls. The intervention was delivered to 49% of fallers, the majority of whom (75%) were left at scene. Their mean age (N=92) was 80±8 years; 78% were women, 39% had annual incomes under $20K, and 34% lived alone. Thirty-five percent reported that an EMT had discussed falls and fall prevention (vs. 8% of comparison group, P<0.01); 84% reported that the information was useful. Six percent reported having made an appointment with a fall prevention program (vs. 3% of comparison group). EMTs reported that the intervention was worthwhile and did not add substantially to their workload. A brief, at-scene intervention is feasible and acceptable to fallers and EMTs. Although it activates only a small percent to seek out fall prevention programs, the public health impact of this low-cost strategy may be substantial

    Evaluation of critical care burden following traumatic injury from two randomized controlled trials

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    Abstract Trauma resuscitation practices have continued to improve with new advances targeting prehospital interventions. The critical care burden associated with severely injured patients at risk of hemorrhage has been poorly characterized. We aim to describe the individual and additive effects of multiorgan failure (MOF) and nosocomial infection (NI) on delayed mortality and resource utilization. A secondary analysis of harmonized data from two large prehospital randomized controlled trials (Prehospital Air Medical Plasma (PAMPer) Trial and Study of Tranexamic Acid during Air and Ground Medical Prehospital Transport (STAAMP) Trial) was conducted. Only those patients who survived beyond the first 24 hours post-injury and spent at least one day in the ICU were included. Patients were stratified by development of MOF only, NI only, both, or neither and diagnosis of early (≤ 3 days) versus late MOF (> 3 days). Risk factors of NI and MOF, time course of these ICU complications, associated mortality, and hospital resource utilization were evaluated. Of the 869 patients who were enrolled in PAMPer and STAAMP and who met study criteria, 27.4% developed MOF only (n = 238), 10.9% developed NI only (n = 95), and 15.3% were diagnosed with both MOF and NI (n = 133). Patients developing NI and/or MOF compared to those who had an uncomplicated ICU course had greater injury severity, lower GCS, and greater shock indexes. Early MOF occurred in isolation, while late MOF more often followed NI. MOF was associated with 65% higher independent risk of 30-day mortality when adjusting for cofounders (OR 1.65; 95% CI 1.04–2.6; p = 0.03), however NI did not significantly affect odds of mortality. NI was individually associated with longer mechanical ventilation, ICU stay, hospital stay, and rehabilitation requirements, and the addition of MOF further increased the burden of inpatient and post-discharge care. MOF and NI remain common complications for those who survive traumatic injury. MOF is a robust independent predictor of mortality following injury in this cohort, and NI is associated with higher resource utilization. Timing of these ICU complications may reveal differences in pathophysiology and offer targets for continued advancements in treatment

    Touchscreen learning deficits and normal social approach behavior in the Shank3B model of Phelan–McDermid Syndrome and autism

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    SHANK3 is a synaptic scaffolding protein localized in the postsynaptic density and has a crucial role in synaptogenesis and neural physiology. Deletions and point mutations in SHANK3 cause Phelan–McDermid Syndrome (PMS), and have also been implicated in autism spectrum disorder (ASD) and intellectual disabilities, leading to the hypothesis that reduced SHANK3 expression impairs basic brain functions that are important for social communication and cognition. Several mouse models of Shank3 deletions have been generated, varying in the specific domain deleted. Here we report impairments in cognitive function in mice heterozygous for exon 13–16 (coding for the PDZ domain) deletion. The touchscreen pairwise discrimination task was chosen by virtue of its: (a) conceptual and technical similarities to the Cambridge Neuropsychological Test Automated Battery (CANTAB) and NIH Toolbox Cognition Battery used for testing cognitive functions in humans, (b) minimal demand on motor abilities, and (c) capability to measure many aspects of learning and memory and complex cognitive functions, including cognitive flexibility. The similarity between our mouse tasks and human cognitive assays means a high translational validity in future intervention studies using preclinical models. Our study revealed that Shank3B heterozygous mice (+/–) were slower to reach criterion in the pairwise visual discrimination task, and exhibited trends toward making more errors (first trial errors) and more correction errors than wildtype mice (+/+). Open field activity was normal in +/–, ruling out hypo- or hyperactivity as potential confounds in the touchscreen test. Sociability in the three chamber test was also normal in both +/+ and +/–. These results indicate a deficit in discrimination learning in the Shank3B model of PMS and ASD, suggesting that this mouse model is a useful preclinical tool for studying neurobiological mechanisms behind cognitive impairments in PMS and ASD. The current findings are the starting point for our future research in which we will investigate multiple domains of cognition and explore pharmacological interventions
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