177 research outputs found
A trial of intracranial pressure monitoring in traumatic brain injury
Background Intracranial pressure (ICP) monitoring is considered the standard of care for severe traumatic brain injury (TBI) and is used frequently, but the efficacy of treatment based on monitoring in improving the outcome has not been rigorously assessed. Methods Objective: The objective was to compare efficacy of guideline-based management in which a protocol for monitoring intraparenchymal ICP was used (ICP group) or a protocol in which treatment was based on imaging and clinical examination (exam group). Design: A multicenter randomized controlled trial was conducted. Setting: The trial was set in ICUs in Bolivia or Ecuador. Subjects: Patients had severe TBI (n = 324) and were 13 years of age or older. Interventions: Patients were randomly allocated to ICP This composite measure was based on performance across 21 measures of functional and cognitive status and was calculated as a percentile (with 0 indicating the worst performance, and 100 the best performance). Results There was no significant between-group difference in the primary outcome, a composite measure based on percentile performance across 21 measures of functional and cognitive status (score 56 in the pressure-monitoring group versus 53 in the imaging-clinical examination group; P= 0.49). Six-month mortality rates were 39% in the pressuremonitoring group and 41% in the imaging-clinical examination group (P = 0.60). The median lengths of stay in the ICU were similar in the two groups (12 days in the pressure-monitoring group and 9 days in the imagingclinical examination group; P = 0.25), although the number of days of brain-specific treatments (for example, administration of hyperosmolar fluids and the use of hyperventilation) in the ICU was higher in the imaging-clinical examination group than in the pressure-monitoring group (4.8 versus 3.4, P = 0.002). The distributions of serious adverse events were similar in the two groups. Conclusions For patients with severe TBI, care focused on maintaining monitored ICP at 20 mmHg or less was not shown to be superior to care based on imaging and clinical examination. monitoring or clinical exam-based monitoring. Outcomes: The primary outcome was a composite of survival time, impaired consciousness, functional status at 3 and 6 months, and neuropsychological status at 6 months; neuropsychological status was assessed by an examiner who was unaware of the protocol assignment. © 2014 BioMed Central Ltd
Regulation of insulin-like growth factor–dependent myoblast differentiation by Foxo forkhead transcription factors
Insulin-like growth factors promote myoblast differentiation through phosphoinositol 3-kinase and Akt signaling. Akt substrates required for myogenic differentiation are unknown. Forkhead transcription factors of the forkhead box gene, group O (Foxo) subfamily are phosphorylated in an insulin-responsive manner by phosphatidylinositol 3-kinase–dependent kinases. Phosphorylation leads to nuclear exclusion and inactivation. We show that a constitutively active Foxo1 mutant inhibits differentiation of C2C12 cells and prevents myotube differentiation induced by constitutively active Akt. In contrast, a transcriptionally inactive mutant Foxo1 partially rescues inhibition of C2C12 differentiation mediated by wortmannin, but not by rapamycin, and is able to induce aggregation-independent myogenic conversion of teratocarcinoma cells. Inhibition of Foxo expression by siRNA resulted in more efficient differentiation, associated with increased myosin expression. These observations indicate that Foxo proteins are key effectors of Akt-dependent myogenesis
Targeting DLL4 in tumors shows preclinical activity but potentially significant toxicity.
Evaluation of: Yan M, Callahan CA, Beyer JC et al.: Chronic DLL4 blockade induces vascular neoplasms. Nature 463, E6-E7 (2010). Delta-like ligand 4 (DLL4) is a Notch ligand that is critical in the formation of a functional vascular network in tumors. Blockade of DLL4-mediated Notch signaling strikingly increases nonproductive angiogenesis, but significantly inhibits tumor growth in preclinical mouse models. Thus, DLL4 has emerged as an attractive target for cancer therapy. Anti-DLL4 antibodies have recently entered clinical trials. However, the potential toxic effects of anti-DLL4 are poorly understood. In this article, Yan et al. reported that chronic DLL4 blockade abnormally activates endothelial cells, causes pathological changes of multiple organs and induces vascular neoplasms. The findings need confirmation in further studies using different tumor-bearing animals but, nevertheless, raise important safety concerns regarding the use of anti-DLL4 agents and warrant monitoring for these effects in clinical trials for targeting DLL4
Age-dependent white matter disruptions after military traumatic brain injury: Multivariate analysis results from ENIGMA brain injury
Mild Traumatic brain injury (mTBI) is a signature wound in military personnel, and repetitive mTBI has been linked to age-related neurogenerative disorders that affect white matter (WM) in the brain. However, findings of injury to specific WM tracts have been variable and inconsistent. This may be due to the heterogeneity of mechanisms, etiology, and comorbid disorders related to mTBI. Non-negative matrix factorization (NMF) is a data-driven approach that detects covarying patterns (components) within high-dimensional data. We applied NMF to diffusion imaging data from military Veterans with and without a self-reported TBI history. NMF identified 12 independent components derived from fractional anisotropy (FA) in a large dataset (n = 1,475) gathered through the ENIGMA (Enhancing Neuroimaging Genetics through Meta-Analysis) Military Brain Injury working group. Regressions were used to examine TBI- and mTBI-related associations in NMF-derived components while adjusting for age, sex, post-traumatic stress disorder, depression, and data acquisition site/scanner. We found significantly stronger age-dependent effects of lower FA in Veterans with TBI than Veterans without in four components (q \u3c 0.05), which are spatially unconstrained by traditionally defined WM tracts. One component, occupying the most peripheral location, exhibited significantly stronger age-dependent differences in Veterans with mTBI. We found NMF to be powerful and effective in detecting covarying patterns of FA associated with mTBI by applying standard parametric regression modeling. Our results highlight patterns of WM alteration that are differentially affected by TBI and mTBI in younger compared to older military Veterans
Low-Dosage Inhibition of DII4 Signaling Promotes Wound Healing by Inducing Functional Neo-Angiogenesis
Recent findings regarding Dll4 function in physiological and pathological conditions indicate that this Notch ligand may constitute an important therapeutic target. Dll4 appears to be a major anti-angiogenic agent, occupying a central role in various angiogenic pathways. The first trials of anti-Dll4 therapy in mice demonstrated a paradoxical effect, as it reduced tumor perfusion and growth despite leading to an increase in vascular density. This is seen as the result of insufficient maturation of the newly formed vasculature causing a circulatory defect and increased tumor hypoxia. As Dll4 function is known to be closely dependent on expression levels, we envisioned that the therapeutic anti-Dll4 dosage could be modulated to result in the increase of adequately functional blood vessels. This would be useful in conditions where vascular function is a limiting factor for recovery, like wound healing and tissue hypoxia, especially in diabetic patients. Our experimental results in mice confirmed this possibility, revealing that low dosage inhibition of Dll4/Notch signaling causes improved vascular function and accelerated wound healing
Molecular Mechanism of the Constitutive Activation of the L250Q Human Melanocortin-4 Receptor Polymorphism †
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65471/1/j.1747-0285.2006.00362.x.pd
Influence of Dll4 via HIF-1α-VEGF Signaling on the Angiogenesis of Choroidal Neovascularization under Hypoxic Conditions
Choroidal neovascularization (CNV) is the common pathological basis of
irreversible visual impairment encountered in a variety of chorioretinal
diseases; the pathogenesis of its development is complicated and still
imperfectly understood. Recent studies indicated that delta-like ligand 4
(Dll4), one of the Notch family ligands might participate in the HIF-1α-VEGF
pathway to regulate CNV angiogenesis. But little is known about the influence
and potential mechanism of Dll4/Notch signals on CNV angiogenesis. Real-time
RT-PCR, Western blotting were used to analyze the expression alteration of Dll4,
VEGF and HIF-1α in hypoxic RF/6A cells. Immunofluorescence staining, a
laser-induced rat CNV model and intravitreal injection techniques were used to
confirm the relationships among these molecules in vitro and
in vivo. RPE-RF/6A cell co-culture systems were used to
investigate the effects of Dll4/Notch signals on CNV angiogenesis. We found that
the Dll4 was involved in hypoxia signaling in CNV angiogenesis. Results from the
co-culture system showed that the enhancement of Dll4 expression in RF/6A cells
led to the significantly faster proliferation and stronger tube forming ability,
but inhibited cells migration and invasion across a monolayer of RPE cells in
hypoxic environment, while siRNA-mediated Dll4 silencing caused the opposite
effects. Pharmacological disruption of Notch signaling using gamma-secretase
inhibitor (GSI) produced similar, but not identical effects, to that caused by
the Dll4 siRNA. In addition, the expression of several key molecules involved in
the angiogenesis of CNV was altered in RF/6A cells showing constitutively active
Dll4 expression. These results suggest that Dll4 play an important role in CNV
angiogenesis, which appears to be regulated by HIF-1α and VEGF during the
progression of CNV under hypoxic conditions. Targeting Dll4/Notch signaling may
facilitate further understanding of the mechanisms that underlie CNV
angiogenesis
Metabolic changes in concussed American football players during the acute and chronic post-injury phases
<p>Abstract</p> <p>Background</p> <p>Despite negative neuroimaging findings many athletes display neurophysiological alterations and post-concussion symptoms that may be attributable to neurometabolic alterations.</p> <p>Methods</p> <p>The present study investigated the effects of sports concussion on brain metabolism using <sup>1</sup>H-MR Spectroscopy by comparing a group of 10 non-concussed athletes with a group of 10 concussed athletes of the same age (mean: 22.5 years) and education (mean: 16 years) within both the acute and chronic post-injury phases. All athletes were scanned 1-6 days post-concussion and again 6-months later in a 3T Siemens MRI.</p> <p>Results</p> <p>Concussed athletes demonstrated neurometabolic impairment in prefrontal and motor (M1) cortices in the acute phase where NAA:Cr levels remained depressed relative to controls. There was some recovery observed in the chronic phase where Glu:Cr levels returned to those of control athletes; however, there was a pathological increase of m-I:Cr levels in M1 that was only present in the chronic phase.</p> <p>Conclusions</p> <p>These results confirm cortical neurometabolic changes in the acute post-concussion phase as well as recovery and continued metabolic abnormalities in the chronic phase. The results indicate that complex pathophysiological processes differ depending on the post-injury phase and the neurometabolite in question.</p
Contested space: The contradictory political dynamics of food banking in the UK
This paper offers a critical reappraisal of the politics of food banking in the UK. Existing work has raised concerns about the institutionalisation of food banks, with charitable assistance apparently – even if inadvertently – undermining collectivist welfare and deflecting attention from fundamental injustices in the food system. This paper presents original ethnographic work that examines the neglected politics articulated within food banks themselves. Conceptualising food banks as potential spaces of encounter where predominantly middle-class volunteers come into contact with ‘poor others’ (Lawson and Elwood, 2013), we illustrate the ways food banks may both reinforce but also rework and generate new, ethical and political attitudes, beliefs and identities. We also draw attention to the limits of these progressive possibilities and examine the ways in which some food banks continue to operate within a set of highly restrictive, and stigmatising, welfare technologies. By highlighting the contradictory dynamics at work in food bank organisations, and among food bank volunteers and clients, we suggest the political role of food banks warrants neither uncritical celebration nor outright dismissal. Rather, food banks represent a highly ambiguous political space still in the making and open to contestatio
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The Curing Coma Campaign: Framing Initial Scientific Challenges—Proceedings of the First Curing Coma Campaign Scientific Advisory Council Meeting
Abstract: Coma and disordered consciousness are common manifestations of acute neurological conditions and are among the most pervasive and challenging aspects of treatment in neurocritical care. Gaps exist in patient assessment, outcome prognostication, and treatment directed specifically at improving consciousness and cognitive recovery. In 2019, the Neurocritical Care Society (NCS) launched the Curing Coma Campaign in order to address the “grand challenge” of improving the management of patients with coma and decreased consciousness. One of the first steps was to bring together a Scientific Advisory Council including coma scientists, neurointensivists, neurorehabilitationists, and implementation experts in order to address the current scientific landscape and begin to develop a framework on how to move forward. This manuscript describes the proceedings of the first Curing Coma Campaign Scientific Advisory Council meeting which occurred in conjunction with the NCS Annual Meeting in October 2019 in Vancouver. Specifically, three major pillars were identified which should be considered: endotyping of coma and disorders of consciousness, biomarkers, and proof-of-concept clinical trials. Each is summarized with regard to current approach, benefits to the patient, family, and clinicians, and next steps. Integration of these three pillars will be essential to the success of the Curing Coma Campaign as will expanding the “curing coma community” to ensure broad participation of clinicians, scientists, and patient advocates with the goal of identifying and implementing treatments to fundamentally improve the outcome of patients
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