2,723 research outputs found
The Value of Comparative Animal Research : Kroghâs Principle Facilitates Scientific Discoveries
There are no conflicts of interest to declare. This paper developed from the 2016 Early Career Impact Award from the Federation of Associations in Behavioral & Brain Sciences to TJS. TJS has received funding from The Leverhulme Trust. FJPE is in receipt of funding from the BBSRC (BB/M001555/1). The National Institutes of Health has funded RDF (NS 034950, NS093277, NIMH 087930), AGO (HD079573, IOS-1354760) and AMK (HD081959). BAA is an Arnold O. Beckman postdoctoral fellow.Peer reviewedPostprin
LesionAir: An Automated, Low-Cost Vision-Based Skin Cancer Diagnostic Tool
Current techniques for diagnosing skin cancer lack specificity and sensitivity, resulting in unnecessary biopsies and missed diagnoses. Automating tissue palpation and morphology quantification will result in a repeatable, objective process. LesionAir is a low-cost skin cancer diagnostic tool that measures the full-field compliance of tissue by applying a vacuum force and measuring the precise deflection using structured light three-dimensional (3D) reconstruction. The technology was tested in a benchtop setting on phantom skin and in a small clinical study. LesionAir has been shown to measure deflection with a 0.085mm root-mean-square (RMS) error and measured the stiffness of phantom tissue to within 20% of finite element analysis (FEA) predictions. After biopsy and analysis, a dermatopathologist confirmed the diagnosis of skin cancer in tissue that LesionAir identified as noticeably stiffer and the regions of this stiffer tissue aligned with the bounds of the lesion. A longitudinal, full-scale study is required to determine the clinical efficacy of the device. This technology shows initial promise as a low-cost tool that could rapidly identify and diagnose skin cancer.National Science Foundation (U.S.) (Grant 1122374
Clinical Outcomes After Four-Level Anterior Cervical Discectomy and Fusion.
Study Design: Retrospective cohort study.
Objectives: Anterior cervical discectomy and fusion (ACDF) demonstrates reliable improvement in neurologic symptoms associated with anterior compression of the cervical spine. There is a paucity of data on outcomes following 4-level ACDFs. The purpose of this study was to evaluate clinical outcomes for patients undergoing 4-level ACDF.
Methods: All 4-level ACDFs with at least 1-year clinical follow-up were identified. Clinical outcomes, including fusion rates, neurologic outcomes, and reoperation rates were determined.
Results: Retrospective review of our institutional database revealed 25 patients who underwent 4-level ACDF with at least 1-year clinical follow-up. Average age was 57.5 years (range 38.2-75.0 years); 14 (56%) were male, and average body mass index was 30.2 kg/m
Conclusions: Review of our institution\u27s experience demonstrated a low rate of revision cervical surgery for any reason of 8% at mean 19 months follow-up, and neurological examinations consistently improved, despite a high rate of radiographic nonunion (31%)
Phosphorylation of a K channel by PKC regulates the excitability of primary sensory neurons and pain signaling
Introduction: Voltage-gated potassium channels (Kvs) play an important role in the termination of neuronal action potentials. Kv3.4 is one of many types of Kv channels, found throughout the human body â including in the axon terminals of dorsal root ganglia neurons. Kv3.4 channels are categorized as A-type currents and have prominent fast-inactivation that has been shown to be phosphorylation dependent. It is hypothesized that following spinal cord injury (SCI), Kv3.4 channels become hyperphosphorylated and their expression reduced â leading to an increase in nociceptive signaling.
Methods: We used embryonic DRG neurons, transfected with one of four types of viral AAV6 constructs, to induce expression of Kv3.4 channels. Constructs included EGFP, WT Kv3.4, Kv3.4 A (phosphonull), Kv3.4 D (phosphomimetic), and Kv3.4 dominant negative (DN).
Results: Kv3.4 constructs were differentially trafficked across embryonic DRG neurons, following AAV1 transfection, as seen through immunofluorescence. Peak currents were increased for WT, A, and D mutants, relative to GFP and DN. The sustained current for phosphomimetic was significantly higher than for GFP and phosphonull (p=0.031). G/Gmax for all traces showed similar activation kinetics. V1/2 was relatively unchanged across constructs. The slow inactivating current was measured at t=50 sec and AP duration for the phosphomimetic Kv3.4 channels was shortened compared with GFP (p=0.018). The rate of repolarization was increased in phosphomimetic constructs, compared with GFP (p=0.044).
Discussion: Phosphorylation of Kv3.4 appears to modulate channel properties and may also play a role in SCI-induced neuropathic pain. Future in vivo experiments can assess pain behavior in animals expressing different Kv3.4 constructs
Perioperative outcomes of a hydrocortisone protocol after endonasal surgery for pituitary adenoma resection
Adrenal insufficiency after transsphenoidal resection of pituitary adenoma (PA) can be seen in 1-12% of cases. In PA, the use of postoperative cortisol measurement and supplementation remains controversial. It is unclear whether postoperative cortisol supplementation has a measurable effect on improving outcomes in patients with pituitary adenoma undergoing endoscopic transsphenoidal surgery (ETS). The objective of the study was to evaluate a postoperative steroid treatment protocol in patients with PA undergoing ETS
Conceptual Ecological Modelling of Sublittoral Rock Habitats to Inform Indicator Selection
The purpose of this study is to produce a series of Conceptual Ecological Models (CEMs)
that represent sublittoral rock habitats in the UK. CEMs are diagrammatic representations of
the influences and processes that occur within an ecosystem. They can be used to identify
critical aspects of an ecosystem that may be studied further, or serve as the basis for the
selection of indicators for environmental monitoring purposes. The models produced by this
project are control diagrams, representing the unimpacted state of the environment free from
anthropogenic pressures.
It is intended that the models produced by this project will be used to guide indicator
selection for the monitoring of this habitat in UK waters. CEMs may eventually be produced
for a range of habitat types defined under the UK Marine Biodiversity Monitoring R&D
Programme (UKMBMP), which, along with stressor models, are designed to show the
interactions within impacted habitats, would form the basis of a robust method for indicator
selection. This project builds on the work to develop CEMs for shallow sublittoral coarse
sediment habitats (Alexander et al 2014).
The project scope included those habitats defined as âsublittoral rockâ. This definition
includes those habitats that fall into the EUNIS Level 3 classifications A3.1 Atlantic and
Mediterranean high energy infralittoral rock, A3.2 Atlantic and Mediterranean moderate
energy infralittoral rock, A3.3 Atlantic and Mediterranean low energy infralittoral rock, A4.1
Atlantic and Mediterranean high energy circalittoral rock, A4.2 Atlantic and Mediterranean
moderate energy circalittoral rock, and A4.3 Atlantic and Mediterranean low energy
circalittoral rock as well as the constituent Level 4 and 5 biotopes that are relevant to UK
waters. A species list of characterising fauna to be included within the scope of the models
was identified using an iterative process to refine the full list of species found within the
relevant Level 5 biotopes.
A literature review was conducted using a pragmatic and iterative approach to gather
evidence regarding species traits and information that would be used to inform the models
and characterise the interactions that occur within the sublittoral rock habitat. All information
gathered during the literature review was entered into a data logging pro-forma spreadsheet
that accompanies this report. Wherever possible, attempts were made to collect information
from UK-specific peer-reviewed studies, although other sources were used where
necessary. All data gathered was subject to a detailed confidence assessment. Expert
judgement by the project team was utilised to provide information for aspects of the models
for which references could not be sourced within the project timeframe.
A multivariate analysis approach was adopted to assess ecologically similar groups (based
on ecological and life history traits) of fauna from the identified species to form the basis of
the models. A model hierarchy was developed based on these ecological groups. One
general control model was produced that indicated the high-level drivers, inputs, biological
assemblages, ecosystem processes and outputs that occur in sublittoral rock habitats. In
addition to this, seven detailed sub-models were produced, which each focussed on a
particular ecological group of fauna within the habitat: âmacroalgaeâ, âtemporarily or
permanently attached active filter feedersâ, âtemporarily or permanently attached passive
filter feedersâ, âbivalves, brachiopods and other encrusting filter feedersâ, âtube building
faunaâ, âscavengers and predatory faunaâ, and ânon-predatory mobile faunaâ. Each sub-model
is accompanied by an associated confidence model that presents confidence in the links
between each model component. The models are split into seven levels and take spatial and
temporal scale into account through their design, as well as magnitude and direction of
influence. The seven levels include regional to global drivers, water column processes, local
inputs/processes at the seabed, habitat and biological assemblage, output processes, local
ecosystem functions, and regional to global ecosystem functions.
The models indicate that whilst the high level drivers that affect each ecological group are
largely similar, the output processes performed by the biota and the resulting ecosystem
functions vary both in number and importance between groups. Confidence within the
models as a whole is generally high, reflecting the level of information gathered during the
literature review.
Physical drivers which influence the ecosystem were found to be of high importance for the
sublittoral rock habitat, with factors such as wave exposure, water depth and water currents
noted to be crucial in defining the biological assemblages. Other important factors such as
recruitment/propagule supply, and those which affect primary production, such as
suspended sediments, light attenuation and water chemistry and temperature, were also
noted to be key and act to influence the food sources consumed by the biological
assemblages of the habitat, and the biological assemblages themselves.
Output processes performed by the biological assemblages are variable between ecological
groups depending on the specific flora and fauna present and the role they perform within
the ecosystem. Of particular importance are the outputs performed by the macroalgae
group, which are diverse in nature and exert influence over other ecological groups in the
habitat. Important output processes from the habitat as a whole include primary and
secondary production, bioengineering, biodeposition (in mixed sediment habitats) and the
supply of propagules; these in turn influence ecosystem functions at the local scale such as
nutrient and biogeochemical cycling, supply of food resources, sediment stability (in mixed
sediment habitats), habitat provision and population and algae control. The export of
biodiversity and organic matter, biodiversity enhancement and biotope stability are the
resulting ecosystem functions that occur at the regional to global scale.
Features within the models that are most useful for monitoring habitat status and change
due to natural variation have been identified, as have those that may be useful for monitoring
to identify anthropogenic causes of change within the ecosystem. Biological, physical and
chemical features of the ecosystem have been identified as potential indicators to monitor
natural variation, whereas biological factors and those physical /chemical factors most likely
to affect primary production have predominantly been identified as most likely to indicate
change due to anthropogenic pressures
Development and characterization of a stable adhesive bond between a poly(dimethylsiloxane) catheter material and a bacterial biofilm resistant acrylate polymer coating
Catheter associated urinary tract infections (CA-UTIs) are the most common health related infections world wide, contributing significantly to patient morbidity and mortality and increased health care costs. To reduce the incidence of these infections, new materials that resist bacterial biofilm formation are needed. A composite catheter material, consisting of bulk PDMS coated with a novel bacterial biofilm resistant polyacrylate (EGDPEAâco-DEGMA) has been proposed. The coated material shows excellent bacterial resistance when compared to commercial catheter materials but delamination of the coatings under mechanical stress presents a challenge. In this work, the use of oxygen plasma treatment to improve the wettability and reactivity of the PDMS catheter material and improve adhesion with the EGDPEAâco-DEGMA coating has been investigated. Argon Cluster 3D-imaging Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) has been used to probe the buried adhesive interface between the EGDPEAâco-DEGMA coating and the treated PDMS. ToF-SIMS analysis was performed in both dry and frozen-hydrated states and results were compared to mechanical tests. From the ToF-SIMS data we have been able to observe the presence of PDMS, silicates, salt particles, cracks and water at the adhesive interface. In the dry catheters, low molecular weight PDMS oligomers at the interface were associated with poor adhesion. When hydrated, the hydrophilic silicates attracted water to the interface and led to easy delamination of the coating. The best adhesion results, under hydrated conditions, were obtained using a combination of 5 min O2 plasma treatment and silane primers. Cryo-ToF-SIMS analysis of the hydrated catheter material showed that the bond between the primed PDMS catheter and the EGDPEAâco-DEGMA coating was stable in the presence of water. The resulting catheter material was resisted Escherichia coli and Proteus mirabilis biofilm colonization by up to 95 % compared with uncoated PDMS after 10 days of continuous bacterial exposure and had the mechanical properties necessary for use as a urinary catheter
Staphylococcus aureus Biofilms Induce Macrophage Dysfunction Through Leukocidin AB and Alpha-Toxin.
UNLABELLED: The macrophage response to planktonic Staphylococcus aureus involves the induction of proinflammatory microbicidal activity. However, S. aureus biofilms can interfere with these responses in part by polarizing macrophages toward an anti-inflammatory profibrotic phenotype. Here we demonstrate that conditioned medium from mature S. aureus biofilms inhibited macrophage phagocytosis and induced cytotoxicity, suggesting the involvement of a secreted factor(s). Iterative testing found the active factor(s) to be proteinaceous and partially agr-dependent. Quantitative mass spectrometry identified alpha-toxin (Hla) and leukocidin AB (LukAB) as critical molecules secreted by S. aureus biofilms that inhibit murine macrophage phagocytosis and promote cytotoxicity. A role for Hla and LukAB was confirmed by using hla and lukAB mutants, and synergy between the two toxins was demonstrated with a lukAB hla double mutant and verified by complementation. Independent confirmation of the effects of Hla and LukAB on macrophage dysfunction was demonstrated by using an isogenic strain in which Hla was constitutively expressed, an Hla antibody to block toxin activity, and purified LukAB peptide. The importance of Hla and LukAB during S. aureus biofilm formation in vivo was assessed by using a murine orthopedic implant biofilm infection model in which the lukAB hla double mutant displayed significantly lower bacterial burdens and more macrophage infiltrates than each single mutant. Collectively, these findings reveal a critical synergistic role for Hla and LukAB in promoting macrophage dysfunction and facilitating S. aureus biofilm development in vivo.
IMPORTANCE: Staphylococcus aureus has a propensity to form multicellular communities known as biofilms. While growing in a biofilm, S. aureus displays increased tolerance to nutrient deprivation, antibiotic insult, and even host immune challenge. Previous studies have shown that S. aureus biofilms thwart host immunity in part by preventing macrophage phagocytosis. It remained unclear whether this was influenced solely by the considerable size of biofilms or whether molecules were also actively secreted to circumvent macrophage-mediated phagocytosis. This is the first report to demonstrate that S. aureus biofilms inhibit macrophage phagocytosis and induce macrophage death through the combined action of leukocidin AB and alpha-toxin. Loss of leukocidin AB and alpha-toxin expression resulted in enhanced S. aureus biofilm clearance in a mouse model of orthopedic implant infection, suggesting that these toxins could be targeted therapeutically to facilitate biofilm clearance in humans
State-Level CPR Education Legislation Associated With Higher Survival After Out-Of-Hospital Cardiac Arrest in Older Adults
Introduction: State-level legislation requiring CPR education prior to high school graduation is associated with an increased likelihood of community-level CPR training. CPR Legislation has also been shown to be associated with increased bystander CPR. We hypothesized that states with CPR Legislation would be associated with higher survival following out-of-hospital cardiac arrest (OHCA).
Methods: Utilizing 2014 Medicare Claims data for emergency department visits and inpatient stays, we identified OHCA via ICD-9-CM code. CPR Legislation data was collected through online statute review. Exposure to CPR Legislation was assessed using the patient state of residence. All disposition categories were considered survival to discharge except for death/hospice. Associations between categorical variables were assessed by chi-squared test. Multiple logistic regression was used to calculate the odds ratio associated with OHCA survival and CPR Legislation, controlling for patient age and sex.
Results: States that passed CPR Legislation in 2013 had the highest survival compared to states with earlier passage or no CPR Legislation (22.2% vs 20.6% vs. 21.8%, respectively, p \u3c 0.001). Results of the multiple logistic regression showed CPR Legislation passed in 2013 was associated with a 12% increase in the odds of survival to discharge compared to states with CPR Legislation prior to 2013 (OR: 1.12, p \u3c0.001).
Discussion: States with CPR Legislation passed in 2013 were associated with higher survival to discharge and discharge to home, compared to earlier adopters and states with no legislation. Further work is needed to assess the mechanisms underlying this relationship
Continuous synthesis of pyridocarbazoles and initial photophysical and bioprobe characterization
Pyridocarbazoles when ligated to transition metals yield high affinity kinase
inhibitors. While batch photocyclizations enable the synthesis of these
heterocycles, the non-oxidative Mallory reaction only provides modest yields
and difficult to purify mixtures. We demonstrate here that a flow-based
Mallory cyclization provides superior results and enables observation of a
clear isobestic point. The flow method allowed us to rapidly synthesize ten
pyridocarbazoles and for the first time to document their interesting
photophysical attributes. Preliminary characterization reveals that these
molecules might be a new class of fluorescent bioprobe
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