Decellularization of human donor aortic and pulmonary valved conduits using low concentration sodium dodecyl sulfate

The clinical use of decellularised cardiac valve allografts is increasing. Long term data will be required to determine whether they outperform conventional cryopreserved allografts. Valves decellularised using different processes may show varied long-term outcomes. It is therefore important to understand the effects of specific decellularisation technologies on the characteristics of donor heart valves. Human cryopreserved aortic and pulmonary valved conduits were decellularised using hypotonic buffer, 0.1% (w/v) SDS and nuclease digestion. The decellularised tissues were compared to cellular cryopreserved valve tissues using histology, immunohistochemistry, quantitation of total DNA, collagen and glycosaminoglycan content, in vitro cytotoxicity assays, uniaxial tensile testing and subcutaneous implantation in mice. The decellularised tissues showed no histological evidence of cells or cell remnants and over 97% DNA removal in all regions (arterial wall, muscle, leaflet and junction). The decellularised tissues retained collagen IV and von Willebrand factor staining with some loss of fibronectin, laminin and chondroitin sulphate staining. There was an absence of MHC Class I staining in decellularised pulmonary valve tissues, with only residual staining in isolated areas of decellularised aortic valve tissues. The collagen content of the tissues was not decreased following decellularisation however the glycosaminoglycan content was reduced. Only moderate changes in the maximum load to failure of the tissues were recorded post-decellularisation. The decellularised tissues were non-cytotoxic in vitro, and were biocompatible in vivo in a mouse subcutaneous implant model. The decellularisation process will now be translated into a GMP compatible process for donor cryopreserved valves with a view to future clinical use

A qualitative study exploring midwives’ perceptions and knowledge of maternal obesity. Reflecting on their experiences of providing healthy eating and weight management advice to pregnant women.

Midwives are responsible for providing advice regarding the complex issues of healthy eating and weight management during pregnancy. This study utilised an inductive data-driven thematic approach in order to determine midwives’ perceptions, knowledge and experiences of providing healthy eating and weight management advice to pregnant women. Semi-structured interviews with 17 midwives were transcribed verbatim and data subjected to thematic analysis. The findings offer insight into the challenges facing midwives in their role trying to promote healthy eating and appropriate weight management to pregnant women. Three core themes were identified: 1) “If they eat healthily it will bring their weight down”: Midwives Misunderstood; 2) “I don’t think we are experienced enough”: Midwives Lack Resources and Expertise, and 3) “BMI of 32 wouldn’t bother me”: Midwives Normalised Obesity. The midwives recognised the importance of providing healthy eating advice to pregnant women and the health risks associated with poor diet and obesity. However, they reported the normalisation of obesity in pregnant women and suggested that this, together with their high workload and lack of expertise, explained the reasons why systematic advice was not in standard antenatal care. In addition, the current lack of UK clinical guidance, and thus possibly lack of clinical leadership, are also preventing delivery of tailored advice. Implementation literature on understanding the barriers to optimal healthcare delivery and informing clinical practice through research evidence needs to be further investigated in this field. This study has recommendations for policy makers, commissioners, service providers and midwives. Keywords: midwives, pregnancy, obesity, healthy eating, qualitative, self-efficac

Effects of Chemical and Radiation Sterilisation on the Biological and Biomechanical Properties of Decellularised Porcine Peripheral Nerves

There is a clinical need for novel graft materials for the repair of peripheral nerve defects. A decellularisation process has been developed for porcine peripheral nerves, yielding a material with potentially significant advantages over other devices currently being used clinically (such as autografts and nerve guidance conduits). Grafts derived from xenogeneic tissues should undergo sterilisation prior to clinical use. It has been reported that sterilisation methods may adversely affect the properties of decellularised tissues, and therefore potentially negatively impact on the ability to promote tissue regeneration. In this study, decellularised nerves were produced and sterilised by treatment with 0.1% (v/v) PAA, gamma radiation (25–28 kGy) or E Beam (33–37 kGy). The effect of sterilisation on the decellularised nerves was determined by cytotoxicity testing, histological staining, hydroxyproline assays, uniaxial tensile testing, antibody labelling for collagen type IV, laminin and fibronectin in the basal lamina, and differential scanning calorimetry. This study concluded that decellularised nerves retained biocompatibility following sterilisation. However, sterilisation affected the mechanical properties (PAA, gamma radiation), endoneurial structure and basement membrane composition (PAA) of decellularised nerves. No such alterations were observed following E Beam treatment, suggesting that this method may be preferable for the sterilisation of decellularised porcine peripheral nerves

Demography and disorders of German Shepherd Dogs under primary veterinarycare in the UK

The German Shepherd Dog (GSD) has been widely used for a variety of working roles. However, concerns for the health and welfare of the GSD have been widely aired and there is evidence that breed numbers are now in decline in the UK. Accurate demographic and disorder data could assist with breeding and clinical prioritisation. The VetCompassTM Programme collects clinical data on dogs under primary veterinary care in the UK. This study included all VetCompassTM dogs under veterinary care during 2013. Demographic, mortality and clinical diagnosis data on GSDs were extracted and reported

In vitro biomechanical and hydrodynamic characterisation of decellularised human pulmonary and aortic roots

Background and purpose of the study: The use of decellularised biological heart valves in the replacement of damaged heart valves offers a promising solution to reduce the degradation issues associated with existing cryopreserved allografts. The purpose of this study was to assess the effect of low concentration sodium dodecyl sulphate decellularisation on the in vitro biomechanical and hydrodynamic properties of cryopreserved human aortic and pulmonary roots. Method: The biomechanical and hydrodynamic properties of cryopreserved decellularised human aortic and pulmonary roots were fully characterised and compared to cellular human aortic and pulmonary roots in an unpaired study. Following review of these results, a further study was performed to investigate the influence of a specific processing step during the decellularisation protocol (‘scraping’) in a paired comparison, and to improve the method of the closed valve competency test by incorporating a more physiological boundary condition. Results: The majority of the biomechanical and hydrodynamic characteristics of the decellularised aortic and pulmonary roots were similar compared to their cellular counterparts. However, several differences were noted, particularly in the functional biomechanical parameters of the pulmonary roots. However, in the subsequent paired comparison of pulmonary roots with and without decellularisation, and when a more appropriate physiological test model was used, the functional biomechanical parameters for the decellularised pulmonary roots were similar to the cellular roots. Conclusion: Overall, the results demonstrated that the decellularised roots would be a potential choice for clinical application in heart valve replacement

Prevalence of Disorders Recorded in Dogs Attending Primary-Care Veterinary Practices in England

Purebred dog health is thought to be compromised by an increasing occurence of inherited diseases but inadequate prevalence data on common disorders have hampered efforts to prioritise health reforms. Analysis of primary veterinary practice clinical data has been proposed for reliable estimation of disorder prevalence in dogs. Electronic patient record (EPR) data were collected on 148,741 dogs attending 93 clinics across central and south-eastern England. Analysis in detail of a random sample of EPRs relating to 3,884 dogs from 89 clinics identified the most frequently recorded disorders as otitis externa (prevalence 10.2%, 95% CI: 9.1-11.3), periodontal disease (9.3%, 95% CI: 8.3-10.3) and anal sac impaction (7.1%, 95% CI: 6.1-8.1). Using syndromic classification, the most prevalent body location affected was the head-and-neck (32.8%, 95% CI: 30.7-34.9), the most prevalent organ system affected was the integument (36.3%, 95% CI: 33.9-38.6) and the most prevalent pathophysiologic process diagnosed was inflammation (32.1%, 95% CI: 29.8-34.3). Among the twenty most-frequently recorded disorders, purebred dogs had a significantly higher prevalence compared with crossbreds for three: otitis externa (P = 0.001), obesity (P = 0.006) and skin mass lesion (P = 0.033), and popular breeds differed significantly from each other in their prevalence for five: periodontal disease (P = 0.002), overgrown nails (P = 0.004), degenerative joint disease (P = 0.005), obesity (P = 0.001) and lipoma (P = 0.003). These results fill a crucial data gap in disorder prevalence information and assist with disorder prioritisation. The results suggest that, for maximal impact, breeding reforms should target commonly-diagnosed complex disorders that are amenable to genetic improvement and should place special focus on at-risk breeds. Future studies evaluating disorder severity and duration will augment the usefulness of the disorder prevalence information reported herein

Spatial Guilds in the Serengeti Food Web Revealed by a Bayesian Group Model

Food webs, networks of feeding relationships among organisms, provide fundamental insights into mechanisms that determine ecosystem stability and persistence. Despite long-standing interest in the compartmental structure of food webs, past network analyses of food webs have been constrained by a standard definition of compartments, or modules, that requires many links within compartments and few links between them. Empirical analyses have been further limited by low-resolution data for primary producers. In this paper, we present a Bayesian computational method for identifying group structure in food webs using a flexible definition of a group that can describe both functional roles and standard compartments. The Serengeti ecosystem provides an opportunity to examine structure in a newly compiled food web that includes species-level resolution among plants, allowing us to address whether groups in the food web correspond to tightly-connected compartments or functional groups, and whether network structure reflects spatial or trophic organization, or a combination of the two. We have compiled the major mammalian and plant components of the Serengeti food web from published literature, and we infer its group structure using our method. We find that network structure corresponds to spatially distinct plant groups coupled at higher trophic levels by groups of herbivores, which are in turn coupled by carnivore groups. Thus the group structure of the Serengeti web represents a mixture of trophic guild structure and spatial patterns, in contrast to the standard compartments typically identified in ecological networks. From data consisting only of nodes and links, the group structure that emerges supports recent ideas on spatial coupling and energy channels in ecosystems that have been proposed as important for persistence.Comment: 28 pages, 6 figures (+ 3 supporting), 2 tables (+ 4 supporting

Interstitial lung disease in children - genetic background and associated phenotypes

Interstitial lung disease in children represents a group of rare chronic respiratory disorders. There is growing evidence that mutations in the surfactant protein C gene play a role in the pathogenesis of certain forms of pediatric interstitial lung disease. Recently, mutations in the ABCA3 transporter were found as an underlying cause of fatal respiratory failure in neonates without surfactant protein B deficiency. Especially in familiar cases or in children of consanguineous parents, genetic diagnosis provides an useful tool to identify the underlying etiology of interstitial lung disease. The aim of this review is to summarize and to describe in detail the clinical features of hereditary interstitial lung disease in children. The knowledge of gene variants and associated phenotypes is crucial to identify relevant patients in clinical practice

Gender Differences in Carbohydrate Metabolism and Carbohydrate Loading

Prior to endurance competition, many endurance athletes participate in a carbohydrate loading regimen in order to help delay the onset of fatigue. The "classic" regimen generally includes an intense glycogen depleting training period of approximately two days followed by a glycogen loading period for 3–4 days, ingesting approximately 60–70% of total energy intake as carbohydrates, while the newer method does not consist of an intense glycogen depletion protocol. However, recent evidence has indicated that glycogen loading does not occur in the same manner for males and females, thus affecting performance. The scope of this literature review will include a brief description of the role of estradiol in relation to metabolism and gender differences seen in carbohydrate metabolism and loading

Addressing the needs of children with disabilities experiencing disaster or terrorism

Purpose of review: This paper reviews the empirical literature on psychosocial factors relating to children with disabilities in the context of disaster or terrorism. Recent findings: Research indicates individuals with disabilities experience increased exposure to hazards due to existing social disparities and barriers associated with disability status. However, studies on the psychological effects of disaster/terrorism on children with preexisting disabilities are exceedingly few and empirical evidence of the effectiveness of trauma-focused therapies for this population is limited. Secondary adversities, including social stigma and health concerns, also compromise the recovery of these children post-disaster/terrorism. Schools and teachers appear to be particularly important in the recovery of children with disabilities to disaster. Disasters, terrorism, and war all contribute to the incidence of disability, as well as disproportionately affect children with preexisting disabilities. Summary: Disaster preparedness interventions and societal changes are needed to decrease the disproportionate environmental and social vulnerability of children with disabilities to disaster and terrorism