Neck muscle cross-sectional area, brain volume and cognition in healthy older men; A cohort study

BACKGROUND: Two important consequences of the normal ageing process are sarcopenia (the age-related loss of muscle mass and function) and age-related cognitive decline. Existing data support positive relationships between muscle function, cognition and brain structure. However, studies investigating these relationships at older ages are lacking and rarely include a measure of muscle size. Here we test whether neck muscle size is positively associated with cognition and brain structure in older men. METHODS: We studied 51 healthy older men with mean age 73.8 (sd 1.5) years. Neck muscle cross-sectional area (CSA) was measured from T1-weighted MR-brain scans using a validated technique. We measured multiple cognitive domains including verbal and visuospatial memory, executive functioning and estimated prior cognitive ability. Whole brain, ventricular, hippocampal and cerebellar volumes were measured with MRI. General linear models (ANCOVA) were performed. RESULTS: Larger neck muscle CSA was associated with less whole brain atrophy (t = 2.86, p = 0.01, partial eta squared 17%). Neck muscle CSA was not associated with other neuroimaging variables or current cognitive ability. Smaller neck muscle CSA was unexpectedly associated with higher prior cognition (t = −2.12, p < 0.05, partial eta squared 10%). CONCLUSIONS: In healthy older men, preservation of whole brain volume (i.e. less atrophy) is associated with larger muscle size. Longitudinal ageing studies are now required to investigate these relationships further

Data associated with 'pH-responsive polymer microcapsules for targeted delivery of biomaterials to the midgut of Drosophila suzukii'

Drosophila suzukii (or spotted wing Drosophila) is an economically important pest which can have a devastating impact on soft and stone fruit industries. Biological pesticides are being sought as alternatives to synthetic chemicals to control this invasive pest, but many are subject to degradation either in the environment or in the insect gut and as a result require protection. In this study we identified a sharp change in pH of the adult midgut from neutral to acidic (pH 6, but underwent rapid dissolution at pH < 4.2. In vivo studies showed that the natural acidity of the midgut of D. suzukii also induced the breakdown of the responsive P2VP microcapsules to release FITC-dextran which was taken up into the body of the insect and accumulated in the renal tubules

Tunable Photocatalytic Selectivity by Altering the Active Center Microenvironment of an Organic Polymer Photocatalyst

The favored production of one product over another is a major challenge in synthetic chemistry, reducing the formation of byproducts and enhancing atom efficacy. The formation of catalytic species that have differing reactivities based on the substrate being converted, has been targeted to selectively control reactions. Here, we report the production of photocatalytic self-assembled amphiphilic polymers, with either hydrophilic or hydrophobic microenvironments at the reactive center. Benzothiadiazole-based photocatalysts were polymerized into either the hydrophilic or the hydrophobic compartment of a diblock copolymer by RAFT polymerization. The difference in the reactivity of each microenvironment was dictated by the physical properties of the substrate. Stark differences in reactivity were observed for polar substrates, where a hydrophilic microenvironment was favored. Conversely, both microenvironments performed similarly for very hydrophobic substrates, showing that reagent partitioning is not the only factor that drives photocatalytic conversion. Furthermore, the use of secondary swelling solvents allowed an additional reagent exchange between the continuous phase and the heterogeneous photocatalyst, resulting in a significant 5-fold increase in conversion for a radical carbon–carbon coupling

The size range of particles ingested by D. suzukii adults.

<p>(<b>a</b>) A micrograph showing polydisperse suspension of PMMA particles dyed red with Sudan III ranging in size from 0.5–200 <b>μ</b>m. (<b>b</b>) Dissected midgut of D. suzukii coloured red from ingested dyed particles but the opacity of gut hindered particle size determination. (<b>c</b>) Solid polymer particles in the fly excrement. The micrograph shows polymer particles resuspended from the excrement allowing particle size to be measured. (<b>d</b>) Comparison of the particle size range in the diet with that found in the excrement (n = 700). The maximum particle size excreted was ~ 15 <b>μ</b>m, which we have used as an approximation for the ingestion limit. Particles < 5 <b>μ</b>m were below the detection limit.</p

In vitro release of FITC-dextran from responsive microcapsules in different pH buffers.

<p>P2VP pH-responsive microcapsules in a pH 6 (n = 4) environment showed no release of encapsulated FITC-dextran over 24 h as the pH was above the pKa of the microcapsules. At the lower pH of 3.8 (n = 4) around 80% of the encapsulated FITC-dextran was released within the first 5 mins, no further release was observed after this time. It is assumed that the unaccounted 20% is lost during the production of the microcapsules.</p

Polymerised multiple emulsion template yielding solid P2VP microcapsules.

<p>(<b>a-d</b>) Optical microscopy of microcapsules formed from polymerisation of the oil phase of the multiple emulsion template. (<b>e</b>) SEM analysis of the loaded microcapsules (<b>f</b>) Size measurement using light scattering, average distribution expressed as volume (%) (n = 10), of the microcapsules ranging from 2–100 <b>μ</b>m. The smaller peak around 1 <b>μ</b>m is a by-product formed of solid polymer particles containing no active species.</p

pH dependence of P2VP microcapsule dissolution.

<p>(<b>a</b>) Determination of the pKa of the microcapsules undertaken by monitoring light transmission (500 nm) as a function of pH. Data (mean±s.e.m; n = 3) were fitted to a sigmoidal curve using OriginPro 9.1 software. (<b>b</b>) Images taken at 0, 3, 6 and 12 sec from a video recording showing the effect of reducing pH on the P2VP microcapsules (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0201294#sec002" target="_blank">methods</a> section) by introducing citric acid. The reduction in pH leads to swelling and rapid dissolution of the microcapsules, releasing their cargo.</p

Prophylaxis for patients at Risk to Eliminate Post-operative Atrial Fibrillation (PREP-AF trial): a protocol for a feasibility randomized controlled study

Abstract Background Postoperative atrial fibrillation (POAF) is a frequent adverse event after thoracic surgery with associated morbidity, mortality, and healthcare costs. It has been shown to be preventable with prophylactic amiodarone, which is only recommended in high-risk individuals due to the potential associated side effects. Risk factors for POAF have been identified and incorporated into a prediction model to identify high-risk patients. Further evaluation in the form of a multicenter clinical trial is required to assess the effectiveness of prophylaxis specifically in this high-risk population. The feasibility of such a trial first needs to be assessed. Methods The PREP-AF trial is a double-blind randomized controlled feasibility trial. Individuals undergoing major thoracic surgery who are identified to be high-risk by the POAF prediction model will be randomized 1:1 to receive a short course of amiodarone vs. placebo in the immediate postoperative period. The primary outcome is feasibility, which will be measured by the number of eligible patients identified, consented, and randomized; intervention adherence; and measurement of future outcomes of a full trial. Discussion This study will determine the feasibility of a randomized controlled trial to assess the effectiveness of prophylactic amiodarone, in high-risk patients undergoing major thoracic surgery. This will inform the development of a multi-center trial to establish if prophylactic amiodarone is safe and effective at reducing the incidence of POAF. Preventing this adverse event will not only improve outcomes for patients but also reduce the associated health resource utilization and costs. Trial registration ClinicalTrials.gov NCT04392921 . Registered on 19 May 2020