Microindentation of fresh soft biological tissue: A rapid tissue sectioning and mounting protocol.

Microindentation of fresh biological tissues is necessary for the creation of 3D biomimetic models that accurately represent the native extracellular matrix microenvironment. However, tissue must first be precisely sectioned into slices. Challenges exist in the preparation of fresh tissue slices, as they can tear easily and must be processed rapidly in order to mitigate tissue degradation. In this study, we propose an optimised mounting condition for microindentation and demonstrate that embedding tissue in a mixture of 2.5% agarose and 1.5% gelatin is the most favourable method of tissue slice mounting for microindentation. This protocol allows for rapid processing of fresh biological tissue and is applicable to a variety of tissue types.

Results from Ireland North and South's 2022 report card on physical activity for children and adolescents.

Background: The Ireland North and South Report Card on Physical Activity (PA) for Children and Adolescents aims to monitor progress in PA participation across a range of internationally established indicators. Methods: Data were collated for 11 indicators and graded following the harmonised Active Healthy Kids Global Alliance report card process. Six representative studies (sample size range n = 898 to n = 15,557) were primarily used in the grading, with many indicators supplemented with additional studies and reports. Data collected since the implementation of COVID-19 public health measures in March 2020 were excluded. Results: Grades were awarded as follows: 'Overall physical activity', C-; 'Organised Sport and Physical Activity', C; 'Active Play', INC; 'Sedentary Behaviours', C-; 'Physical Fitness', INC; 'Family and Peers', D+; 'School', C-; 'Physical Education', D; 'Community and Environment', B+ and 'Government', B. Separate grades were awarded for disability as follows; 'Overall physical activity', F; 'Organised Sport and Physical Activity', D; 'Sedentary Behaviours', C-; 'Family and Peers', C; 'School', C- and 'Government', B. 'Active Play', 'Physical Fitness', 'Physical Education' and 'Community and Environment' were all graded INC for disability. Since the last report card in 2016, four grades remained the same, three increased ('Overall physical activity', 'School' and 'Physical Education') and two ('Family and Peers,' and 'Government') were awarded grades for the first time. Conclusion: Grades specific to children and adolescents with disability were generally lower for each indicator. While small improvements have been shown across a few indicators, PA levels remain low across many indicators for children and adolescents.

Pressure ulcers in patients with COVID-19 acute respiratory distress syndrome undergoing prone positioning in the intensive care unit: A pre- and post-intervention study.

BACKGROUND: Prone positioning has been widely used to improve oxygenation and reduce ventilator-induced lung injury in patients with severe COVID-19 acute respiratory distress syndrome (ARDS). One major complication associated with prone positioning is the development of pressure ulcers (PUs). AIM: This study aimed to determine the impact of a prevention care bundle on the incidence of PUs in patients with COVID-19 ARDS undergoing prone positioning in the intensive care unit. STUDY DESIGN: This was a single-centre pre and post-test intervention study which adheres to the Standards for Reporting Implementation Studies (StaRI) guidelines. The intervention included a care bundle addressing the following: increasing frequency of head turns, use of an open gel head ring, application of prophylactic dressings to bony prominences, use of a pressure redistribution air mattress, education of staff in the early identification of evolving PUs through regular and rigorous skin inspection and engaging in bedside training sessions with nursing and medical staff. The primary outcome of interest was the incidence of PU development. The secondary outcomes of interest were severity of PU development and the anatomical location of the PUs. RESULTS: In the pre-intervention study, 20 patients were included and 80% (n = 16) of these patients developed PUs, comprising 34 ulcers in total. In the post-intervention study, a further 20 patients were included and 60% (n = 12) of these patients developed PUs, comprising 32 ulcers in total. This marks a 25% reduction in the number of patients developing a PU, and a 6% decrease in the total number of PUs observed. Grade II PUs were the most prevalent in both study groups (65%, n = 22; 88%, n = 28, respectively). In the post-intervention study, there was a reduction in the incidence of grade III and deep tissue injuries (pre-intervention 6%, n = 2 grade III, 6% n = 2 deep tissue injuries; post-intervention no grade III ulcers, grade IV ulcers, or deep tissues injuries were recorded). However, there was an increase in the number of unstageable PUs in the post-intervention group with 6% (n = 2) of PUs being classified as unstageable, meanwhile there were no unstageable PUs in the pre-intervention group. This is an important finding to consider as unstageable PUs can indicate deep tissue damage and therefore need to be considered alongside PUs of a more severe grade (grade III, grade IV, and deep tissue injuries). CONCLUSION: The use of a new evidence-based care bundle for the prevention of PUs in the management of patients in the prone position has the potential to reduce the incidence of PU development. Although improvements were observed following alterations to standard practice, further research is needed to validate these findings. RELEVANCE TO CLINICAL PRACTICE: The use of a new, evidence-based care bundle in the management of patients in the prone position has the potential to reduce the incidence of PUs.

Tools for manipulation and positioning of microtissues.

Complex three-dimensional (3D) in vitro models are emerging as a key technology to support research areas in personalised medicine, such as drug development and regenerative medicine. Tools for manipulation and positioning of microtissues play a crucial role in the microtissue life cycle from production to end-point analysis. The ability to precisely locate microtissues can improve the efficiency and reliability of processes and investigations by reducing experimental time and by providing more controlled parameters. To achieve this goal, standardisation of the techniques is of primary importance. Compared to microtissue production, the field of microtissue manipulation and positioning is still in its infancy but is gaining increasing attention in the last few years. Techniques to position microtissues have been classified into four main categories: hydrodynamic techniques, bioprinting, substrate modification, and non-contact active forces. In this paper, we provide a comprehensive review of the different tools for the manipulation and positioning of microtissues that have been reported to date. The working mechanism of each technique is described, and its merits and limitations are discussed. We conclude by evaluating the potential of the different approaches to support progress in personalised medicine.

Are all domains created equal? An exploration of stakeholder views on the concept of physical literacy.

BACKGROUND: Developing physical literacy at population levels provides a transformative appeal for those working in sport, health, education, recreation and physical activity settings. Interdisciplinary approaches to development of policy in this area is recommended. The purpose of this study was to gather empirical data from key stakeholders working with young people in areas related to physical literacy across the Republic of Ireland and Northern Ireland, to capture their current understanding and awareness of the physical literacy to help inform the development of the first all-island consensus statement for physical literacy. METHODS: A total of 1,241 participants (52% male), from a range of stakeholder groups (health, physical activity, sport, recreation and education) completed a researcher developed physical literacy questionnaire. A one-way MANOVA was carried out to investigate differences across stakeholder grouping in terms of perceived importance of three domains of physical literacy. Overlap of independent confidence intervals was analysed to determine importance of the physical literacy domains within stakeholder grouping. RESULTS: A majority (63%) of respondents indicated they were aware of an existing definition of physical literacy, but this varied by stakeholder group (e.g. 86% for higher education, versus 47% of coaches). Participants working in higher education (69%), or working as physical education specialists (67%), were more likely to rate themselves as experts or near experts in physical literacy, while coaches, education generalists, and decision makers were more likely rate themselves as having no expertise (9%, 12% and 12% respectively). Non-specialist teachers and physical education teachers rated the importance of all domains of physical literacy significantly higher than decision makers, and significantly higher than coaches in the cognitive and affective domains. All stakeholders significantly rated the importance of the physical/psychomotor domain of physical literacy higher than the affective or cognitive domains of physical literacy. CONCLUSIONS: Differences observed across stakeholder groups underline the importance of developing a shared vision for physical literacy, and the need to clarify and gain consensus on a definition of the term and its domains. Engaging and understanding the voice of stakeholders is critical in ensuring the relevance, ownership of and commitment to physical literacy statement operationalisation.

Cell specific variation in viability in suspension in in vitro Poiseuille flow conditions.

The influence of Poiseuille flow on cell viability has applications in the areas of cancer metastasis, lab-on-a-chip devices and flow cytometry. Indeed, retaining cell viability is important in the emerging field of adoptive cell therapy, as cells need to be returned to patients' bodies, while the viability of other cells, which are perhaps less accustomed to suspension in a fluidic environment, is important to retain in flow cytometers and other such devices. Despite this, it is unclear how Poiseuille flow affects cell viability. Following on from previous studies which investigated the viability and inertial positions of circulating breast cancer cells in identical flow conditions, this study investigated the influence that varying flow rate, and the corresponding Reynolds number has on the viability of a range of different circulating cells in laminar pipe flow including primary T-cells, primary fibroblasts and neuroblastoma cells. It was found that Reynolds numbers as high as 9.13 had no effect on T-cells while the viabilities of neuroblastoma cells and intestinal fibroblasts were significantly reduced in comparison. This indicates that in vitro flow devices need to be tailored to cell-specific flow regimes.

Socio-ecological correlates of physical activity in a nationally representative sample of adolescents across Ireland and Northern Ireland.

Physical activity (PA) is associated with a range of health benefits for adolescents. Few adolescents meet one hour daily of moderate-to-vigorous physical activity (MVPA). The World Health Organisation (WHO) now recommends an 'on average' accumulation. In light of these updates, comparing correlates associated with meeting versus not meeting the PA guidelines provides limited understanding of adolescent behavioural choices. The aim of this study was to fractionate PA behaviour and investigate influential socio-ecological correlates across a diverse range of PA categories. A nationally representative sample (N = 6,563; age = 13.5 ± 1.9 years; male = 46.2%) completed a researcher supervised self-report survey. Empirically established instruments assessing the socio-ecological correlates of PA were included. Levels of MPVA were categorised into daily active (60mins.MVPA.daily), active (60mins.MVPA.5-6 days), somewhat active (60mins.MVPA.3-4 days) or inactive (60mins.MVPA.0-2 days). Descriptive statistics, chi-square analyses and multivariate blockwise binary logistic regression models were run separately for each PA category. Few were daily active (12.7%), 33.6% active, 36.5% somewhat active and 17.2% were inactive. Results showed that correlates differed in terms of direction and strength, depending on individual activity status. Increasing age was positively associated with being somewhat active, but not with being active or daily active. Attending an 'all-girls school' was negatively associated with daily active. High interpersonal support from family, friends or teachers was negatively associated with inactive or somewhat active, reducing the likelihood of adolescents remaining in these unhealthy PA categories. This novel information is useful for exploring previously established inconsistent relationships with PA. More sensitive categorisation and intervention tailoring to diverse PA categories is required.

Gradients in the in vivo intestinal stem cell compartment and their in vitro recapitulation in mimetic platforms.

Intestinal tissue, and specifically its mucosal layer, is a complex and gradient-rich environment. Gradients of soluble factor (BMP, Noggin, Notch, Hedgehog, and Wnt), insoluble extracellular matrix proteins (laminins, collagens, fibronectin, and their cognate receptors), stromal stiffness, oxygenation, and sheer stress induced by luminal fluid flow at the crypt-villus axis controls and supports healthy intestinal tissue homeostasis. However, due to current technological challenges, very few of these features have so far been included in in vitro intestinal tissue mimetic platforms. In this review, the tightly defined and dynamic microenvironment of the intestinal tissue is presented in detail. Additionally, the authors introduce the current state-of-the-art intestinal tissue mimetic platforms, as well as the design drawbacks and challenges they face while attempting to capture the complexity of the intestinal tissue's physiology. Finally, the compositions of an "idealized" mimetic system is presented to guide future developmental efforts.

The influence of cell elastic modulus on inertial positions in Poiseuille microflows.

Microchannels are used as a transportation highway for suspended cells both in vivo and ex vivo. Lymphatic and cardiovascular systems transfer suspended cells through microchannels within the body, and microfluidic techniques such as lab-on-a-chip devices, flow cytometry, and CAR T-cell therapy utilize microchannels of similar sizes to analyze or separate suspended cells ex vivo. Understanding the forces that cells are subject to while traveling through these channels are important because certain applications exploit these cell properties for cell separation. This study investigated the influence that cytoskeletal impairment has on the inertial positions of circulating cells in laminar pipe flow. Two representative cancer cell lines were treated using cytochalasin D, and their inertial positions were investigated using particle streak imaging and compared between benign and metastatic cell lines. This resulted in a shift in inertial positions between benign and metastatic as well as treated and untreated cells. To determine and quantify the physical changes in the cells that resulted in this migration, staining and nanoindentation techniques were then used to determine the cells' size, circularity, and elastic modulus. It was found that the cells' exposure to cytochalasin D resulted in decreased elastic moduli of cells, with benign and metastatic cells showing decreases of 135 ± 91 and 130 ± 60 Pa, respectively, with no change in either size or shape. This caused benign, stiffer cancer cells to be more evenly distributed across the channel width than metastatic, deformable cancer cells; additionally, a decrease in the elastic moduli of both cell lines resulted in increased migration toward the channel center. These results indicate that the elastic modulus may play more of a part in the inertial migration of such cells than previously thought.

Physical Activity, Sport and Physical Education in Northern Ireland School Children: A Cross-Sectional Study.

Internationally, insufficient physical activity (PA) is a major health concern. Children in Northern Ireland (NI) are recorded as having the lowest levels of PA in the United Kingdom (UK). To date, validated and representative data on the PA levels of NI school children are limited. The aim of this study was to provide surveillance data on self-reported PA, sport and physical education (PE) participation of school children in NI. Differences between genders and factors associated with PA were also examined. A representative sample of primary (n = 446) and post-primary (n = 1508) children was surveyed in school using validated self-report measures. Findings suggest that PA levels are low, with a minority of children (13%) meeting the PA guidelines (primary pupils 20%, post-primary pupils 11%). NI school children have lower levels of PA, PE and sports participation than UK and European peers. A trend of age-related decline across all the domains of PA was apparent. The data presented highlighted that females are less likely to achieve PA guidelines, children from lower socio-economic background participate in school and community sport less often, and that enjoyment and social support are important variables in PA adherence. Policy solutions that would support implementation e.g., mandatory minimum PE time, whole school approaches to PA promotion and targeted investment in schools, particularly in areas of deprivation and for females, are suggested.

Author Correction: The in vitro inertial positions and viability of cells in suspension under different in vivo flow conditions.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

The in vitro inertial positions and viability of cells in suspension under different in vivo flow conditions.

The influence of Poiseuille flow on cell viability has applications in the areas of cancer metastasis, lab-on-a-chip devices and flow cytometry. Indeed, retaining cell viability is important in the emerging field of cell therapy as cells need to be returned to patients' bodies. Despite this, it is unclear how this fundamental fluid regime affects cell viability. This study investigated the influence that varying flow rate, and the corresponding wall shear stress (τw) has on the viability and inertial positions of circulating cells in laminar pipe flow. The viability of two representative cell lines under different shear stresses in two different systems were investigated while particle streak imaging was used to determine their inertial positions. It was found that peristaltic pumps have a negative effect on cell viability in comparison to syringe pumps. Increasing shear stress in a cone and plate above 3 Pa caused an increase in cell death, however, τw as high as 10 Pa in circulation has little to no effect on cell viability. Inertial lift forces that move cells towards the centre of the channel protect them from experiencing detrimental levels of τw, indicating that τw in Poiseuille flow is not a good predictor of cell viability during advection.