959 research outputs found

    Quantification of intracellular payload release from polymersome nanoparticles

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    Polymersome nanoparticles (PMs) are attractive candidates for spatio-temporal controlled delivery of therapeutic agents. Although many studies have addressed cellular uptake of solid nanoparticles, there is very little data available on intracellular release of molecules encapsulated in membranous carriers, such as polymersomes. Here, we addressed this by developing a quantitative assay based on the hydrophilic dye, fluorescein. Fluorescein was encapsulated stably in PMs of mean diameter 85 nm, with minimal leakage after sustained dialysis. No fluorescence was detectable from fluorescein PMs, indicating quenching. Following incubation of L929 cells with fluorescein PMs, there was a gradual increase in intracellular fluorescence, indicating PM disruption and cytosolic release of fluorescein. By combining absorbance measurements with flow cytometry, we quantified the real-time intracellular release of a fluorescein at a single-cell resolution. We found that 173 ± 38 polymersomes released their payload per cell, with significant heterogeneity in uptake, despite controlled synchronisation of cell cycle. This novel method for quantification of the release of compounds from nanoparticles provides fundamental information on cellular uptake of nanoparticle-encapsulated compounds. It also illustrates the stochastic nature of population distribution in homogeneous cell populations, a factor that must be taken into account in clinical use of this technology.</p

    Diet‐induced iron deficiency in rats impacts small intestinal calcium and phosphate absorption

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    Aims: Recent reports suggest that iron deficiency impacts both intestinal calcium and phosphate absorption, although the exact transport pathways and intestinal segment responsible have not been determined. Therefore, we aimed to systematically investigate the impact of iron deficiency on the cellular mechanisms of transcellular and paracellular calcium and phosphate transport in different regions of the rat small intestine. Methods: Adult, male Sprague‐Dawley rats were maintained on a control or iron deficient diet for two weeks and changes in intestinal calcium and phosphate uptake were determined using the in situ intestinal loop technique. The circulating levels of the hormonal regulators of calcium and phosphate were determined by ELISA, while the expression of transcellular calcium and phosphate transporters, and intestinal claudins were determined using qPCR and western blotting. Results: Diet‐induced iron deficiency significantly increased calcium absorption in the duodenum but had no impact in the jejunum and ileum. In contrast, phosphate absorption was significantly inhibited in the duodenum and to a lesser extent the jejunum, but remained unchanged in the ileum. The changes in duodenal calcium and phosphate absorption in the iron deficient animals were associated with increased claudin 2 and 3 mRNA and protein levels, while levels of parathyroid hormone, fibroblast growth factor‐23 and 1,25‐dihydroxy vitamin D3 were unchanged. Conclusion: We propose that iron deficiency alters calcium and phosphate transport in the duodenum. This occurs via changes to the paracellular pathway, whereby upregulation of claudin 2 increases calcium absorption and upregulation of claudin 3 inhibits phosphate absorption

    Feasibility of trial procedures for a randomised controlled trial of a community based group exercise intervention for falls prevention for visually impaired older people: the VIOLET study

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    Background Visually impaired older people (VIOP) have a higher risk of falling than their sighted peers, and are likely to avoid physical activity. The aim was to adapt the existing Falls Management Exercise (FaME) programme for VIOP, delivered in the community, and to investigate the feasibility of conducting a definitive randomised controlled trial (RCT) of this adapted intervention. Methods Two-centre randomised mixed methods pilot trial and economic evaluation of the adapted group-based FaME programme for VIOP versus usual care. A one hour exercise programme ran weekly over 12 weeks at the study sites (Newcastle and Glasgow), delivered by third sector (voluntary and community) organisations. Participants were advised to exercise at home for an additional two hours over the week. Those randomised to the usual activities group received no intervention. Outcome measures were completed at baseline, 12 and 24 weeks. The potential primary outcome was the Short Form Falls Efficacy Scale – International (SFES-I). Participants’ adherence was assessed by reviewing attendance records and self-reported compliance to the home exercises. Adherence with the course content (fidelity) by instructors was assessed by a researcher. Adverse events were collected in a weekly phone call. Results Eighteen participants, drawn from community-living VIOP were screened; 68 met the inclusion criteria; 64 participants were randomised with 33 allocated to the intervention and 31 to the usual activities arm. 94% of participants provided data at the 12 week visit and 92% at 24 weeks. Adherence was high. The intervention was found to be safe with 76% attending nine or more classes. Median time for home exercise was 50 min per week. There was little or no evidence that fear of falling, balance and falls risk, physical activity, emotional, attitudinal or quality of life outcomes differed between trial arms at follow-up. Conclusions The intervention, FaME, was implemented successfully for VIOP and all progression criteria for a main trial were met. The lack of difference between groups on fear of falling was unsurprising given it was a pilot study but there may have been other contributory factors including suboptimal exercise dose and apparent low risk of falls in participants. These issues need addressing for a future trial

    A mixed methods approach to evaluating community drug distributor performance in the control of neglected tropical diseases

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    BACKGROUND: Trusted literate, or semi-literate, community drug distributors (CDDs) are the primary implementers in integrated preventive chemotherapy (IPC) programmes for Neglected Tropical Disease (NTD) control. The CDDs are responsible for safely distributing drugs and for galvanising communities to repeatedly, often over many years, receive annual treatment, create and update treatment registers, monitor for side-effects and compile treatment coverage reports. These individuals are 'volunteers' for the programmes and do not receive remuneration for their annual work commitment. METHODS: A mixed methods approach, which included pictorial diaries to prospectively record CDD use of time, structured interviews and focus group discussions, was used to triangulate data on how 58 CDDs allocated their time towards their routine family activities and to NTD Programme activities in Uganda. The opportunity costs of CDD time were valued, performance assessed by determining the relationship between time and programme coverage, and CDD motivation for participating in the programme was explored. RESULTS: Key findings showed approximately 2.5 working weeks (range 0.6-11.4 working weeks) were spent on NTD Programme activities per year. The amount of time on NTD control activities significantly increased between the one and three deliveries that were required within an IPC campaign. CDD time spent on NTD Programme activities significantly reduced time available for subsistence and income generating engagements. As CDDs took more time to complete NTD Programme activities, their treatment performance, in terms of validated coverage, significantly decreased. Motivation for the programme was reported as low and CDDs felt undervalued. CONCLUSIONS: CDDs contribute a considerable amount of opportunity cost to the overall economic cost of the NTD Programme in Uganda due to the commitment of their time. Nevertheless, programme coverage of at least 75 %, as required by the World Health Organisation, is not being achieved and vulnerable individuals may not have access to treatment as a consequence of sub-optimal performance by the CDDs due to workload and programmatic factors

    Peripheral innate immune and bacterial signals relate to clinical heterogeneity in Parkinson's disease.

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    The innate immune system is implicated in Parkinson's disease (PD), but peripheral in-vivo clinical evidence of the components and driving mechanisms involved and their relationship with clinical heterogeneity and progression to dementia remain poorly explored. We examined changes in peripheral innate immune-related markers in PD cases (n = 41) stratified according to risk of developing early dementia. 'Higher Risk'(HR) (n = 23) and 'Lower Risk' (LR) (n = 18) groups were defined according to neuropsychological predictors and MAPT H1/H2 genotype, and compared to age, gender and genotype-matched controls. Monocyte subsets and expression of key surface markers were measured using flow cytometry. Serum markers including alpha-synuclein, inflammasome-related caspase-1 and bacterial translocation-related endotoxin were measured using quantitative immuno-based assays. Specific markers were further investigated using monocyte assays and validated in plasma samples from a larger incident PD cohort (n = 95). We found that classical monocyte frequency was elevated in PD cases compared to controls, driven predominantly by the HR group, in whom Toll-Like Receptor (TLR)4+ monocytes and monocyte Triggering Receptor Expressed on Myeloid cells-2 (TREM2) expression were also increased. Monocyte Human Leukocyte Antigen (HLA)-DR expression correlated with clinical variables, with lower levels associated with worse cognitive/motor performance. Notably, monocyte changes were accompanied by elevated serum bacterial endotoxin, again predominantly in the HR group. Serum alpha-synuclein and inflammasome-related caspase-1 were decreased in PD cases compared to controls regardless of group, with decreased monocyte alpha-synuclein secretion in HR cases. Further, alpha-synuclein and caspase-1 correlated positively in serum and monocyte lysates, and in plasma from the larger cohort, though no associations were seen with baseline or 36-month longitudinal clinical data. Principal Components Analysis of all monocyte and significant serum markers indicated 3 major components. Component 1 (alpha-synuclein, caspase-1, TLR2+ monocytes) differentiated PD cases and controls in both groups, while Component 2 (endotoxin, monocyte TREM2, alpha-synuclein) did so predominantly in the HR group. Component 3 (classical monocytes, alpha-synuclein) also differentiated cases and controls overall in both groups. These findings demonstrate that systemic innate immune changes are present in PD and are greatest in those at higher risk of rapid progression to dementia. Markers associated with PD per-se (alpha-synuclein, caspase-1), differ from those related to cognitive progression and clinical heterogeneity (endotoxin, TREM2, TLR4, classical monocytes, HLA-DR), with mechanistic and therapeutic implications. Alpha-synuclein and caspase-1 are associated, suggesting inflammasome involvement common to all PD, while bacterial translocation associated changes may contribute towards progression to Parkinson's dementia. Additionally, HLA-DR-associated variations in antigen presentation/clearance may modulate existing clinical disease

    A multicentre study of the evidence for customized margins in photon breast boost radiotherapy

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    Objective:To determine if subsets of patients may benefit from smaller or larger margins when using laser setup and bony anatomy verification of breast tumour bed (TB) boost radiotherapy (RT).Methods: Verification imaging data acquired using cone-beam CT, megavoltage CT or two-dimensional kilovoltage imaging on 218 patients were used (1574 images). TB setup errors for laser-only setup (dlaser) and for bony anatomy verification (dbone) were determined using clips implanted into the TB as a gold standard for the TB position. Cases were grouped by centre-, patient- and treatment-related factors, including breast volume, TB position, seroma visibility and surgical technique. Systematic (?) and random (?) TB setup errors were compared between groups, and TB planning target volume margins (MTB) were calculated.Results: For the study population, ?laser was between 2.8 and 3.4?mm, and ?bone was between 2.2 and 2.6?mm, respectively. Females with larger breasts (p?=?0.03), easily visible seroma (p???0.02) and open surgical technique (p???0.04) had larger ?laser. ?bone was larger for females with larger breasts (p?=?0.02) and lateral tumours (p?=?0.04). Females with medial tumours (p?&lt;?0.01) had smaller ?bone.Conclusion:If clips are not used, margins should be 8 and 10?mm for bony anatomy verification and laser setup, respectively. Individualization of TB margins may be considered based on breast volume, TB and seroma visibility.Advances in knowledge:Setup accuracy using lasers and bony anatomy is influenced by patient and treatment factors. Some patients may benefit from clip-based image guidance more than others

    Establishing a clinical phenotype for cachexia in end stage kidney disease - study protocol.

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    BACKGROUND: Surveys using traditional measures of nutritional status indicate that muscle wasting is common among persons with end-stage kidney disease (ESKD). Up to 75% of adults undergoing maintenance dialysis show some evidence of muscle wasting. ESKD is associated with an increase in inflammatory cytokines and can result in cachexia, with the loss of muscle and fat stores. At present, only limited data are available on the classification of wasting experienced by persons with ESKD. Individuals with ESKD often exhibit symptoms of anorexia, loss of lean muscle mass and altered energy expenditure. These symptoms are consistent with the syndrome of cachexia observed in other chronic diseases, such as cancer, heart failure, and acquired immune deficiency syndrome. While definitions of cachexia have been developed for some diseases, such as cardiac failure and cancer, no specific cachexia definition has been established for chronic kidney disease. The importance of developing a definition of cachexia in a population with ESKD is underscored by the negative impact that symptoms of cachexia have on quality of life and the association of cachexia with a substantially increased risk of premature mortality. The aim of this study is to determine the clinical phenotype of cachexia specific to individuals with ESKD. METHODS: A longitudinal study which will recruit adult patients with ESKD receiving haemodialysis attending a Regional Nephrology Unit within the United Kingdom. Patients will be followed 2 monthly over 12 months and measurements of weight; lean muscle mass (bioelectrical impedance, mid upper arm muscle circumference and tricep skin fold thickness); muscle strength (hand held dynamometer), fatigue, anorexia and quality of life collected. We will determine if they experience (and to what degree) the known characteristics associated with cachexia. DISCUSSION: Cachexia is a debilitating condition associated with an extremely poor outcome. Definitions of cachexia in chronic illnesses are required to reflect specific nuances associated with each disease. These discrete cachexia definitions help with the precision of research and the subsequent clinical interventions to improve outcomes for patients suffering from cachexia. The absence of a definition for cachexia in an ESKD population makes it particularly difficult to study the incidence of cachexia or potential treatments, as there are no standardised inclusion criteria for patients with ESKD who have cachexia. Outcomes from this study will provide much needed data to inform development and testing of potential treatment modalities, aimed at enhancing current clinical practice, policy and education

    Conceptualising social justice and sociocultural issues within physical education teacher education: international perspectives

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    Background: Physical education (PE) and physical education teacher education (PETE) have a substantial literature base that advocates for students to develop a critical consciousness, appreciate multiple perspectives, and engage in actions to enhance social justice (Tinning 2016). Analysing sociocultural issues, critically reflecting on beliefs, knowledge, biography and values, and developing a sense of agency to enact change, have been recognised as an integral part of the PETE knowledge base for some time (Fernández-Balboa 1997). However, there remain differences in how social justice itself is conceptualised and enacted. Social justice is aligned heavily with critical and ‘post’ theories where taking action for justice, democracy and power are central; but social justice is also found in humanist beliefs in student-centredness and equality and has been co-opted by neoliberal forces that promote individual responsibility. While a lack of consensus is not in itself a problem (Bialystok 2014), diverse definitions might contribute to confusion (Randall and Robinson 2016) and lead to uncertainty over what and how to teach for social justice. Purpose: In order to work towards greater certainty around concepts of social justice in the PETE community, this project sought to map variations in definition and conceptualisation of social justice and sociocultural issues among physical education teacher educators (PETEs) and physical education and sport pedagogy (PESP) educators, as part of a wider project on social justice and sociocultural perspectives and practices in PETE. Methods: PETE and PESP faculty (n=72) in North America, Europe, and Australasia engaged in an in-depth interview, during which they were asked how they define social justice and sociocultural issues. Additional information about participants’ social identity was collected. A constant comparative method of analysing participants’ definitions mapped a range of concepts building on the theoretical framework of neoliberal, humanist, critical and ‘post’ approaches to social justice. Findings: The data demonstrate that there are a range of understandings about sociocultural issues and social justice. Most commonly, some participants articulated a humanist approach to social justice by encouraging their pre-service teachers (PSTs) to have awareness of equality of opportunity in relation to gender, sexuality and/or racism. Less prevalent, but strongly stated by those who conceptualised social justice in these terms, was the importance to take action for democracy, empowerment or critical reflection. The terms diversity and equality, framed in neoliberal and humanist discourses, were most commonly used within the United States (US), while critical pedagogy and alignment with critical and ‘post’ theories were more prevalent in Australia and New Zealand. Conclusion: Differences exist in the ways social justice is conceptualised in PETE. While this can be attributed to the influence of local issues, it is also reflective of what intellectual tools, such as humanism or critical theory, are available for problematising social issues. The range of non-critical concepts found raises concern that PSTs are not getting the tools to enact social justice or tackle sociocultural issues.
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