Fate and behaviour of Microplastics (> 25µm) within the water distribution network, from water treatment works to service reservoirs and customer taps

Water treatment works have previously shown high efficiency in removing microplastics > 25 µm from raw source water. However, what is less well known is the extent to which microplastics of this size class are generated or lost within the water distribution network, particularly whether there is a greater presence in the customer tap than in the water treatment works outlet. This study focused on the presence of 21 different types of synthetic polymer particles with sizes larger than 25 µm examined through multiple rounds of sampling at outlets of water treatment works (WTW), service reservoirs (SR), and customer taps (CT) managed by seven different water companies in Britain. Nineteen different types of polymers were detected; their signature and concentration varied based on the round of sampling, the location within the water supply network, and the water company responsible for managing the supply. Among the polymers examined, polyamide (PA), polyethene terephthalate (PET), polypropylene (PP), and polystyrene (PS) were the most commonly found. Apart from PET having its highest concentration of 0.0189 microplastic per litre (MP/L) in the SR, the concentrations of the other three most frequent polymers (PS = 0.017 MP/L, PA = 0.0752 MP/L, PP= 0.1513 MP/L) were highest in the CT. The overall prevalence of this size of microplastics in the network is low, but there was a high variability of polymer types and occurrences. These spatial and temporal variations suggested that the MP in the distribution network may exist as a series of pulses. Given the presence and polymer types, the potential for some of the microplastics to originate from materials used in the water network and domestic plumbing systems cannot be ruled out. As found before, the absolute number of microplastics in the water distribution network remained extremely low.

The Childhood Resilience Study: Resilience and emotional and behavioural wellbeing experienced by Australian Aboriginal and Torres Strait Islander boys and girls aged 5-9 years

BACKGROUND

Resilience is a process of drawing on internal or external strengths to regain, sustain or improve adaptive outcomes despite adversity. Using a child resilience measure co-designed with Aboriginal and Torres Strait Islander communities, we investigate: 1) children's personal, family, school and community strengths; 2) gender differences; and 3) associations between resilience and wellbeing.

METHODS

1132 parent/caregivers of children aged 5-12 years were recruited to the Childhood Resilience Study, including through the Aboriginal Families Study. The Aboriginal Families Study is a population-based cohort of 344 mothers of an Aboriginal and/or Torres Strait Islander child. This paper focuses on the wave 2 survey data on child resilience at age 5-9 years (n = 231). Resilience was assessed with the Child Resilience Questionnaire-parent/caregiver report (CRQ-P/C), categorised into tertiles of low, moderate and high scores. Child emotional/behavioural wellbeing and mental health competence was assessed with the parent-report Strengths and Difficulties Questionnaire. All Tobit regression models adjusted for child age.

OUTCOMES

Aboriginal and Torres Strait Islander girls had higher resilience scores compared to boys (Adj.β = 0·9, 95%CI 0·9-1·4), with higher School Engagement, Friends and Connectedness to language scale scores. Resilience scores were strongly associated with wellbeing and high mental health competence. A higher proportion of girls with low resilience scores had positive wellbeing than did boys (73.3% versus 49.0%). High resilience scores were associated with lower SDQ total difficulties score after adjusting for child age, gender, maternal age and education and family location (major city, regional, remote) (Adj.β = -3.4, 95%CI -5.1, -1.7). Compared to the Childhood Resilience Study sample, Aboriginal Families Study children had higher mean CRQ-P/C scores in the personal and family domains.

INTERPRETATION

High family strengths can support Aboriginal and Torres Strait Islander children at both an individual and cultural level. Boys may benefit from added scaffolding by schools, family and communities to support their social and academic connectedness.

Significant Turning Point: Common Buzzard (Buteo buteo) Exposure to Second-Generation Anticoagulant Rodenticides in the United Kingdom

Second-generation anticoagulant rodenticides (SGARs) are widely used to control rodent populations, resulting in the serious secondary exposure of predators to these contaminants. In the United Kingdom (UK), professional use and purchase of SGARs were revised in the 2010s. Certain highly toxic SGARs have been authorized since then to be used outdoors around buildings as resistance-breaking chemicals under risk mitigation procedures. However, it is still uncertain whether and how these regulatory changes have influenced the secondary exposure of birds of prey to SGARs. Based on biomonitoring of the UK Common Buzzard (Buteo buteo) collected from 2001 to 2019, we assessed the temporal trend of exposure to SGARs and statistically determined potential turning points. The magnitude of difenacoum decreased over time with a seasonal fluctuation, while the magnitude and prevalence of more toxic brodifacoum, authorized to be used outdoors around buildings after the regulatory changes, increased. The summer of 2016 was statistically identified as a turning point for exposure to brodifacoum and summed SGARs that increased after this point. This time point coincided with the aforementioned regulatory changes. Our findings suggest a possible shift in SGAR use to brodifacoum from difenacoum over the decades, which may pose higher risks of impacts on wildlife.

Co-occurrence of macroplastics, microplastics, and legacy and emerging plasticisers in UK soils

Despite a theoretical link between plastic and plasticiser occurrence in the terrestrial environment, there are few empirical studies of the relationship between these contaminants in soils. We carried out a field study to assess the co-occurrence of plastic waste, and legacy and emerging plasticisers in UK soils (n = 19) from various land uses (woodlands, urban roadsides, urban parklands, landfill-associated). Surface plastics and soil microplastics were quantified and characterised using ATR-FTIR and μ-FTIR. Eight legacy (phthalate) and three emerging (adipate, citrate, trimellitate) plasticisers were quantified using GC-MS. Surface plastics were found at higher prevalence at landfill-associated and urban roadside sites, with levels significantly (2 orders of magnitude) greater than in woodlands. Microplastics were detected in landfill-associated (mean 12.3 particles g^-1 dw), urban roadside (17.3 particles g^-1 dw) and urban parkland (15.7 particles g^-1 dw) soils, but not in woodland soils. The most commonly detected polymers were polyethene, polypropene and polystyrene. Mean ∑plasticiser concentration in urban roadside soils (3111 ng g^-1 dw) was significantly higher than in woodlands (134 ng g^-1 dw). No significant difference was found between landfill-associated (318 ng g^-1 dw) and urban parkland (193 ng g^-1 dw) soils and woodlands. Di-n-butyl phthalate (94.7% detection frequency) and the emerging plasticiser trioctyl trimellitate (89.5%) were the most commonly detected plasticisers, with diethylhexyl phthalate (493 ng g^-1 dw) and di-iso-decyl phthalate (96.7 ng g^-1 dw) present at the highest concentrations. ∑plasticiser concentrations were significantly correlated with surface plastic (R² = 0.23), but not with soil microplastic concentrations. Whilst plastic litter seems a fundamental source of plasticisers in soils, mechanisms such as airborne transport from source areas may be as important. Based on the data from this study, phthalates remain the dominant plasticisers in soils, but emerging plasticisers are already widespread, as reflected by their presence in all land uses studied.

A Study of Arizona Physician Relocation Patterns by Rurality and Primary Care Status

BACKGROUND AND OBJECTIVES

Physician location is an important element of health care access. However, physician shortages and disparities in geographic distribution exist. This study examines physician locations, relocation patterns, and factors associated with relocating.

METHODS

We used Arizona licensure data and rural-urban commuting area (RUCA) codes to identify Arizona physicians and their office or mailing address locations. Our sample included Arizona physicians estimated to be younger than 70 years of age who had an active license between in 2014 and 2019. We used multivariable logistic regression to assess physicians' adjusted odds of relocating in Arizona by RUCA code, primary care status, age, gender, and medical education location.

RESULTS

We identified 11,202 Arizona physicians in our sample, 33% of whom changed practice addresses within Arizona between 2014 and 2019. Primary care physicians (PCPs) in large rural areas had lower odds of relocating in Arizona (0.62, 95% CI 0.43-0.90) than PCPs in urban areas. Compared to 64-69-year-old physicians, those less than 34 and 34-43 years old had statistically higher odds of relocating within Arizona.

CONCLUSIONS

Primary care status and rurality are important factors consider to understand physician relocation patterns. We found that a substantial number of Arizona physicians relocated within Arizona between 2014 and 2019, and few of those who relocated (2%) moved to a more rural area.

Long-term trends of second generation anticoagulant rodenticides (SGARs) show widespread contamination of a bird-eating predator, the Eurasian Sparrowhawk (Accipiter nisus) in Britain

Second generation anticoagulant rodenticides (SGARs) are widely used to control rodents around the world. However, contamination by SGARs is detectable in many non-target species, particularly carnivorous mammals or birds-of-prey that hunt or scavenge on poisoned rodents. The SGAR trophic transfer pathway via rodents and their predators/scavengers appears widespread, but little is known of other pathways of SGAR contamination in non-target wildlife. This is despite the detection of SGARs in predators that do not eat rodents, such as specialist bird-eating hawks. We used a Bayesian modelling framework to examine the extent and spatio-temporal trends of SGAR contamination in the livers of 259 Eurasian Sparrowhawks, a specialist bird-eating raptor, in regions of Britain during 1995-2015. SGARs, predominantly difenacoum, were detected in 81% of birds, with highest concentrations in males and adults. SGAR concentrations in birds were lowest in Scotland and higher or increasing in other regions of Britain, which had a greater arable or urban land cover where SGARs may be widely deployed for rodent control. However, there was no overall trend for Britain, and 97% of SGAR residues in Eurasian Sparrowhawks were below 100 ng/g (wet weight), which is a potential threshold for lethal effects. The results have potential implications for the population decline of Eurasian Sparrowhawks in Britain. Fundamentally, the results indicate an extensive and persistent contamination of the avian trophic transfer pathway on a national scale, where bird-eating raptors and, by extension, their prey appear to be widely exposed to SGARs. Consequently, these findings have implications for wildlife contamination worldwide, wherever these common rodenticides are deployed, as widespread exposure of non-target species can apparently occur via multiple trophic transfer pathways involving birds as well as rodents.

Exploring dimensions of quality-of-life in survivors of stroke with communication disabilities - a brief report

BACKGROUND

People with communication disabilities post-stroke have poor quality-of-life.

OBJECTIVES

We aimed to explore the association of self-reported communication disabilities with different dimensions of quality-of-life between 90 and 180 days post-stroke.

METHODS

Cross-sectional survey data were obtained between 90 and 180 days post-stroke from registrants in the Australian Stroke Clinical Registry recruited from three hospitals in Queensland. The usual follow-up survey included the EQ5D-3L. Responses to the Hospital Anxiety and Depression Scale, and extra questions (e.g. communication disabilities) were also collected. We used χ² statistics to determine differences.

RESULTS

Overall, 244/647 survivors completed the survey. Respondents with communication disabilities (n = 72) more often reported moderate to extreme problems in all EQ5D-3L dimensions, than those without communication disabilities (n = 172): anxiety or depression (74% vs 40%, p < .001), pain or discomfort (58% vs 39%, p = .006), self-care (46% vs 18%, p < .001), usual activities (77% vs 49%, p < .001), and mobility (68% vs 35%, p < .001). Respondents with communication disabilities reported less fatigue (66% vs 89%, p < .001), poorer cognitive skills (thinking) (16% vs 1%, p < .001) and lower social participation (31% vs 6%, p < .001) than those without communication disabilities.

CONCLUSIONS

Survivors of stroke with communication disabilities are more negatively impacted across different dimensions of quality-of-life (as reported between 90 and 180 days post-stroke) compared to those without communication disabilities. This highlights the need for timely and on-going comprehensive multidisciplinary person-centered support.

Ensuring Access to Albuterol in Schools: From Policy to Implementation. An Official ATS/AANMA/ALA/NASN Policy Statement

Rationale: For children with asthma, access to quick-relief medications is critical to minimizing morbidity and mortality. An innovative and practical approach to ensure access at school is to maintain a supply of stock albuterol that can be used by any student who experiences respiratory distress. To make this possible, state laws allowing for stock albuterol are needed to improve medication access.

Objectives: To provide policy recommendations and outline steps for passing and implementing stock albuterol laws.

Methods: We assembled a diverse stakeholder group and reviewed guidelines, literature, statutes, regulations, and implementation documents related to school-based medication access. Stakeholders were divided into two groups—legislation and implementation—on the basis of expertise. Each group met virtually to review documents and draft recommendations. Recommendations were compiled and revised in iterative remote meetings with all stakeholders.

Main Results: We offer several recommendations for crafting state legislation and facilitating program implementation. 1) Create a coalition of stakeholders to champion legislation and implement stock albuterol programs. The coalition should include school administrators, school nurses and health personnel, parents, or caregivers of children with asthma, pediatric primary care and subspecialty providers (e.g., pulmonologists/allergists), pharmacists, health department staff, and local/regional/national advocacy organizations. 2) Legislative components critical for effective implementation of stock albuterol programs include specifying that medication can be administered in good faith to any child in respiratory distress, establishing training requirements for school staff, providing immunity from civil liability for staff and prescribers, ensuring pharmacy laws allow prescriptions to be dispensed to schools, and suggesting inhalers with valved holding chambers/spacers for administration. 3) Select an experienced and committed legislator to sponsor legislation and guide revisions as needed during passage and implementation. This person should be from the majority party and serve on the legislature’s health or education committee. 4) Develop plans to disseminate legislation and regulations/policies to affected groups, including school administrators, school nurses, pharmacists, emergency responders, and primary/subspecialty clinicians. Periodically evaluate implementation effectiveness and need for adjustments.

Conclusions: Stock albuterol in schools is a safe, practical, and potentially life-saving option for children with asthma, whether asthma is diagnosed or undiagnosed, who lack access to their personal quick-relief medication. Legislation is imperative for aiding in the adoption and implementation of school stock albuterol policies, and key policy inclusions can lay the groundwork for success. Future work should focus on passing legislation in all states, implementing policy in schools, and evaluating the impact of such programs on academic and health outcomes.

Organizational Readiness for Community Health Worker Workforce Integration Among Medicaid Contracted Health Plans and Provider Networks: An Arizona Case Study

Understanding and building organizational capacity for system change and the integration of the Community Health Worker (CHW) workforce within the health scare sector requires a supportive organizational culture among sector leaders and providers. The aim of this mixed-methods study was to assess organizational readiness for CHW workforce integration into Arizona Medicaid health systems and care teams. This collaborative effort was in direct response to emergent state and national CHW workforce policy opportunities, and the shifting health care landscape in Arizona – which merged behavior and physical health. Specifically, and in collaboration with a broad-based, statewide CHW workforce coalition, led by the CHW professional association, we assessed 245 licensed health care professionals with experience working with CHWs and 16 Medicaid-contracted health plan leadership. Our goal was to generate a baseline understanding of the knowledge, attitudes and beliefs these stakeholders held about the integration of CHWs into systems and teams. Our findings demonstrate a high level of organizational readiness and action toward integration of CHWs within the Arizona health care system and care teams. CHWs have emerged as a health care workforce able to enhance the patient experience of care, improve population health, reduce cost of care, and improve the experience of providing care among clinicians and staff.

683 A Quality Improvement Project (QIP) To Increase Compliance with Peri-Operative Antibiotic Guidelines in Colorectal Surgery (CS)

Introduction

In CS, the correct use of antibiotics is important in order to reduce the risk of surgical site and intra-abdominal infections, whilst balancing risks from overuse of antibiotics. The Commissioning for Quality and Improvement (CQUIN) of 2019/20 identified that antibiotic prophylaxis guideline compliance could be enhanced in CS. This QIP aimed to improve local CS antibiotic prophylaxis and extension guideline compliance.

Method

In December 2019, an educational session was held to highlight the details of the local guideline and prescribing discrepancies. A3 posters of the guideline were created for accessible reference in operating theatres. Perioperative antibiotic prescription data from all colorectal elective cases in January 2020 were extracted and analysed using descriptive methods.

Results

Out of 93 cases in the sample, 70 (75.3%) were compliant with the prophylaxis guideline. However, metronidazole was commonly used in perianal surgery, which is not recommended. 13 cases required extension of the antibiotic course, of which seven were compliant (53.8%). The main issues included: use of agents and course durations which were not indicated; and a lack of antibiotic switch after a pause in therapy.

Conclusions

To further improve compliance with antibiotic guidelines, targeting historic practice, increasing awareness, and making systemic change is required for the next cycle.

Chemicals with increasingly complex modes of action result in greater variation in sensitivity between earthworm species

The scale of variation in species sensitivity to toxicants has been theoretically linked to mode of action. Specifically, it has been proposed there will be greater variations for chemicals with a putative specific biological target than for toxicants with a non-specific narcotic mechanism. Here we test the hypothesis that mode of action is related to variation in sensitivity in a specifically designed experiment for species from a single ecologically important terrestrial taxa, namely earthworms. Earthworm toxicity tests were conducted with five species for four chemicals, providing a series of increasingly complex modes of action: a putative narcotic polycyclic aromatic hydrocarbon (fluoranthene), and three insecticides (chlorpyrifos, cypermethrin, imidacloprid) with known neuronal receptor targets. Across all the chemicals, the standard epigeic test species Eisenia fetida and Lumbricus rubellus, were generally among the two least sensitive, while the endogenic Aporrectodea caliginosa and Megascolecidae Amynthas gracilis were generally more sensitive (never being among the two least sensitive species). This indicates a potential for bias in the earthworm ecotoxicology literature, which is dominated by studies in epigeic Lumbricidae, but contains few endogeic or Megascolecidae data. Results confirmed the lowest range of variation in sensitivities for effects on reproduction was for fluoranthene (2.5 fold). All insecticides showed greater variation for species sensitivity (cypermethrin: 7.5 fold, chlorpyrifos: 10.3 fold, imidacloprid: 31.5 fold) consistent with the specific mechanisms of the pesticides. Difference in toxicodynamics, based on mode of action specificity and receptor complexity was reflected in the magnitude of sensitivity variation. However, measurements of tissue concentrations also indicated the potential importance of toxicokinetics in explaining species sensitivity variations for chlorpyrifos and cypermethrin.

Establishing voluntary certification of community health workers in Arizona: a policy case study of building a unified workforce

BACKGROUND

Community health workers (CHWs) are widely recognized as essential to addressing disparities in health care delivery and outcomes in US vulnerable populations. In the state of Arizona, the sustainability of the workforce is threatened by low wages, poor job security, and limited opportunities for training and advancement within the profession. CHW voluntary certification offers an avenue to increase the recognition, compensation, training, and standardization of the workforce. However, passing voluntary certification legislation in an anti-regulatory state such as Arizona posed a major challenge that required a robust advocacy effort.

CASE PRESENTATION

In this article, we describe the process of unifying the two major CHW workforces in Arizona, promotoras de salud in US-Mexico border communities and community health representatives (CHRs) serving American Indian communities. Differences in the origins, financing, and even language of the population-served contributed to historically divergent interests between CHRs and promotoras. In order to move forward as a collective workforce, it was imperative to integrate the perspectives of CHRs, who have a regular funding stream and work closely through the Indian Health Services, with those of promotoras, who are more likely to be grant-funded in community-based efforts. As a unified workforce, CHWs were better positioned to gain advocacy support from key health care providers and health insurance companies with policy influence. We seek to elucidate the lessons learned in our process that may be relevant to CHWs representing diverse communities across the US and internationally.

CONCLUSIONS

Legislated voluntary certification provides a pathway for further professionalization of the CHW workforce by establishing a standard definition and set of core competencies. Voluntary certification also provides guidance to organizations in developing appropriate training and job activities, as well as ongoing professional development opportunities. In developing certification with CHWs representing different populations, and in particular Tribal Nations, it is essential to assure that the CHW definition is in alignment with all groups and that the scope of practice reflects CHW roles in both clinic and community-based settings. The Arizona experience underscores the benefits of a flexible approach that leverages existing strengths in organizations and the population served.

Accumulation of polybrominated diphenyl ethers and microbiome response in the great pond snail Lymnaea stagnalis with exposure to nylon (polyamide) microplastics

Microplastics attract widespread attention, including for their potential to transport toxic chemicals in the form of plasticisers and associated hydrophobic organic chemicals, such as polybrominated diphenyl ethers (PBDEs). The aims of this study were to investigate how nylon (polyamide) microplastics may affect PBDE accumulation in snails, and the acute effects of nylon particles and PBDEs on survival, weight change and inherent microbiome diversity and community composition of the pond snail Lymnaea stagnalis. Snails were exposed for 96 h to BDEs-47, 99, 100 and 153 in the presence and absence of 1% w/w nylon microplastics in quartz sand sediment. No mortality was observed over the exposure period. Snails not exposed to microplastics lost significantly more weight compared to those exposed to microplastics. Increasing PBDE concentration in the sediment resulted in an increased PBDE body burden in the snails, however microplastics did not significantly influence total PBDE uptake. Based on individual congeners, uptake of BDE 47 by snails was significantly reduced in the presence of microplastics. The diversity and composition of the snail microbiome was not significantly altered by the presence of PBDEs nor by the microplastics, singly or combined. Significant effects on a few individual operational taxonomic units (OTUs) occurred when comparing the highest PBDE concentration with the control treatment, but in the absence of microplastics only. Overall within these acute experiments, only subtle effects on weight loss and slight microbiome alterations occurred. These results therefore highlight that L. stagnalis are resilient to acute exposures to microplastics and PBDEs, and that microplastics are unlikely to influence HOC accumulation or the microbiome of this species over short timescales.

3D collagen architecture induces a conserved migratory and transcriptional response linked to vasculogenic mimicry

The topographical organization of collagen within the tumor microenvironment has been implicated in modulating cancer cell migration and independently predicts progression to metastasis. Here, we show that collagen matrices with small pores and short fibers, but not Matrigel, trigger a conserved transcriptional response and subsequent motility switch in cancer cells resulting in the formation of multicellular network structures. The response is not mediated by hypoxia, matrix stiffness, or bulk matrix density, but rather by matrix architecture-induced β1-integrin upregulation. The transcriptional module associated with network formation is enriched for migration and vasculogenesis-associated genes that predict survival in patient data across nine distinct tumor types. Evidence of this gene module at the protein level is found in patient tumor slices displaying a vasculogenic mimicry (VM) phenotype. Our findings link a collagen-induced migration program to VM and suggest that this process may be broadly relevant to metastatic progression in solid human cancers.

Extracellular matrix plays a central role in driving cancer development. Here the authors using an in vitro approach show that confining collagen architectures induce fast and persistent cell migration and the formation of multicellular network structures linked to vascular mimicry observed in tumours from patients.

Are energy and protein requirements met in hospital?

BACKGROUND

Malnutrition is a problem within hospitals, which impacts upon clinical outcomes. The present audit assesses whether a hospital menu meets the energy and protein standards recommended by the British Dietetic Association's (BDA) Nutrition and Hydration Digest and determines the contribution of oral nutrition supplements (ONS) and additional snacks.

METHODS

Patients in a UK South West hospital were categorised as 'nutritionally well' or 'nutritionally vulnerable' in accordance with their Malnutrition Universal Screening Tool score. Energy and protein content of food selected from the menu ('menu choice'), menu food consumed ('hospital intake') and total food consumed including snacks ('overall intake') were calculated and compared with the standards.

RESULTS

In total, 93 patients were included. For 'nutritionally well' patients (n = 81), energy and protein standards were met by 11.1% and 33.3% ('menu choice'); 7.4% and 22.2% ('hospital intake'); and 14.8% and 28.4% ('overall intake'). For 'nutritionally vulnerable' patients (n = 12), energy and protein standards were met by 0% and 8.3% ('menu choice'); 0% and 8.3% ('hospital intake'); and 8.3% and 16.7% ('overall intake'). Ten percent of patients consumed ONS. Patients who consumed hospital snacks (34%) were more likely to meet the nutrient standards (P ≤ 0.001).

CONCLUSIONS

The present audit demonstrated that most patients are not meeting the nutrient standards recommended by the BDA Nutrition and Hydration Digest. Recommendations include the provision of energy/protein-dense snacks, as well as menu, offering ONS where clinically indicated, in addition to training for staff. A food services dietitian is ideally placed to lead this, forming a vital link between patients, caterers and clinical teams.

Spatial patterns and environmental constraints on ecosystem services at a catchment scale

Improved understanding and prediction of the fundamental environmental controls on ecosystem service supply across the landscape will help to inform decisions made by policy makers and land-water managers. To evaluate this issue for a local catchment case study, we explored metrics and spatial patterns of service supply for water quality regulation, agriculture production, carbon storage, and biodiversity for the Macronutrient Conwy catchment. Methods included using ecosystem models such as LUCI and JULES, integration of national scale field survey datasets, earth observation products and plant trait databases, to produce finely resolved maps of species richness and primary production. Analyses were done with both 1×1km gridded and subcatchment data. A common single gradient characterised catchment scale ecosystem services supply with agricultural production and carbon storage at opposing ends of the gradient as reported for a national-scale assessment. Species diversity was positively related to production due to the below national average productivity levels in the Conwy combined with the unimodal relationship between biodiversity and productivity at the national scale. In contrast to the national scale assessment, a strong reduction in water quality as production increased was observed in these low productive systems. Various soil variables were tested for their predictive power of ecosystem service supply. Soil carbon, nitrogen, their ratio and soil pH all had double the power of rainfall and altitude, each explaining around 45% of variation but soil pH is proposed as a potential metric for ecosystem service supply potential as it is a simple and practical metric which can be carried out in the field with crowd-sourcing technologies now available. The study emphasises the importance of considering multiple ecosystem services together due to the complexity of covariation at local and national scales, and the benefits of exploiting a wide range of metrics for each service to enhance data robustness.

Exercise and the Regulation of Mitochondrial Turnover

Exercise is a well-known stimulus for the expansion of the mitochondrial pool within skeletal muscle. Mitochondria have a remarkable ability to remodel their networks and can respond to an array of signaling stimuli following contractile activity to adapt to the metabolic demands of the tissue, synthesizing proteins to expand the mitochondrial reticulum. In addition, when they become dysfunctional, these organelles can be recycled by a specialized intracellular system. The signals regulating this mitochondrial life cycle of synthesis and degradation during exercise are still an area of great research interest. As mitochondrial turnover has valuable consequences in physical performance, in addition to metabolic health, disease, and aging, consideration of the signals which control this cycle is vital. This review focuses on the regulation of mitochondrial turnover in skeletal muscle and summarizes our current understanding of the impact that exercise has in modulating this process.

Laparoscopic ventral mesh rectopexy in the management of solitary rectal ulcer syndrome: a cause for optimism?

AIM

The treatment of solitary rectal ulcer syndrome (SRUS) is notoriously difficult. Laparoscopic ventral mesh rectopexy (LVMR) is a nonresectional technique for patients with full thickness external rectal prolapse and internal prolapse with obstructed defaecation syndrome (ODS), features associated in the pathogenesis of SRUS. Our aim was to assess the short- and long-term efficacy of LVMR in treating SRUS.

METHOD

Forty-eight patients with SRUS who underwent LVMR over a 15-year period (December 1996 to July 2012) were identified from a prospectively maintained electronic database.

RESULTS

Forty-eight patients, 38 (79%) women, median age 43 (18-80) years, median body mass index 26 (21-40) kg/m(2) underwent LVMR for SRUS after initial biofeedback. The median follow-up was 33 months (95% CI 31-55, range 1-186 months); 52% were followed for more than 3 years and 13 (27%) for more than 5 years. Five (10%) had relapsed following a response to stapled transanal rectal resection (STARR; 10 additional patients have had a continued response to STARR). Eleven (23%) had intermittent reducible external prolapse. Epithelial ulcer healing was reported in all patients at 3 months. The ODS scores improved by 68% (P < 0.0001) and quality of life (QoL; Birmingham Bowel and Urinary Symptoms Questionnaire-22) scores improved by 45% (P < 0.0001). There was a significant improvement in bowel visual analogue scale (VAS) scores at 3 and 12 months (P = 0.0007). Sustained improvement in QoL and VAS scores was maintained at 2 years and continued in the 52% followed up for between 3 and 15 years. There were four (8%) symptomatic ODS recurrences: posterior rectal wall prolapse successfully treated by STARR (3) and one symptom free for 2 years following a temporary loop ileostomy. There were two recurrences (4%).

CONCLUSION

LVMR appears to provide a sustained improvement in QoL, VAS and patient satisfaction in patients with SRUS. Morbidity, recurrence and safety profiles are low.

Determining E. coli burden on pasture in a headwater catchment: combined field and modelling approach

Empirical monitoring studies of catchment-scale Escherichia coli burden to land from agriculture are scarce. This is not surprising given the complexity associated with the temporal and spatial heterogeneity in the excretion of livestock faecal deposits and variability in microbial content of faeces. However, such information is needed to appreciate better how land management and landscape features impact on water quality draining agricultural landscapes. The aim of this study was to develop and test a field-based protocol for determining the burden of E. coli in a small headwater catchment in the UK. Predictions of E. coli burden using an empirical model based on previous best estimates of excretion and shedding rates were also evaluated against observed data. The results indicated that an empirical model utilising key parameters was able to satisfactorily predict E. coli burden on pasture most of the time, with 89% of observed values falling within the minimum and maximum range of predicted values. In particular, the overall temporal pattern of E. coli burden on pasture is captured by the model. The observed and predicted values recorded a disagreement of >1 order of magnitude on only one of the nine sampling dates throughout an annual period. While a first approximation of E. coli burden to land, this field-based protocol represents one of the first comprehensive approaches for providing a real estimate of a dynamic microbial reservoir at the headwater catchment scale and highlights the utility of a simple dynamic empirical model for a more economical prediction of catchment-scale E. coli burden.

Faster pulmonary oxygen uptake kinetics in children vs adults due to enhancements in oxygen delivery and extraction

This study aimed to examine if the faster pulmonary oxygen uptake (VO2p) phase 2 in children could be explained by increased O2 availability or extraction at the muscle level. For that purpose, O2 availability and extraction were assessed using deoxyhemoglobin (HHb) estimated by near-infrared spectroscopy during moderate-intensity constant load cycling exercise in children and young adults. Eleven prepubertal boys and 12 men volunteered to participate in the study. They performed one maximal graded exercise to determine the power associated with the gas exchange threshold (GET) and four constant load exercises at 90% of GET. VO2p and HHb were continuously monitored. VO2p , HHb, and estimated capillary blood flow (Qcap) kinetics were modelled after a time delay and characterized by the time to achieve 63% of the amplitude (τ) and by mean response time (MRT: time delay + τ), respectively. Mean values of τ for VO2p (P < 0.001), of MRT for HHb (P < 0.01) and of MRT for Qcap (P < 0.001) were significantly shorter in children. Faster VO2p kinetics have been shown in children; these appear due to both faster O2 extraction and delivery kinetics as indicated by faster HHb and Qcap kinetics, respectively.

Medium-term results of stapled transanal rectal resection (STARR) for obstructed defecation and symptomatic rectal-anal intussusception

AIM

Stapled transanal rectal resection (STARR) is an increasingly accepted treatment for obstructed defaecation syndrome (ODS) associated with internal rectal prolapse (IRP) and rectocoele. The aim of this study is to evaluate the medium to long-term outcomes of STARR for ODS.

METHOD

The intermediate-term results of STARR used over a 9-year period were reviewed from the analysis of a prospectively maintained database. Patients were followed for a median period of 98 (95% CI 85-112, range 5-386) weeks.

RESULTS

Three hundred and forty-four (234 woman) patients of median age 54 (19-90) years underwent STARR over a 9-year period. Preoperative symptoms included pelvic pain (93%), incomplete evacuation (90%), urgency (74%), a sensation of obstruction (65%) and rectal digitation (27%). Thirteen had the solitary rectal ulcer syndrome. Of 326 patients with follow-up data, 249 (76%) were followed beyond 1 year and 149 (43%) beyond 2 years. The ODS score improved [14.6 ± 5.4 pre vs 1.6 ± 3.1 post (P < 0.0001)] as did the faecal incontinence (FI) score [3.5 ± 3.3 pre vs 0.4 ± 1.3 post (P < 0.0001)]. Fifteen (4.3%) patients reported deterioration in FI, and 11 (3.2%) experienced new onset minor incontinence. Urgency was 72% at 8 weeks, 20% at 16 weeks, 11.5% at 52 weeks and 5% at 1.5 years. None of the 29 patients followed beyond 4 years reported urgency. Urgency was unrelated to sex, age or preoperative ODS symptoms (Mantel-Cox log-rank). Recurrent symptoms of ODS occurred in 4.9%. Eighty-one per cent of patients were highly satisfied with STARR and would recommend or have it again.

CONCLUSION

STARR was successful for the treatment of selected patients with ODS and IRP. Postoperative faecal urgency rapidly decreases with time. It is not possible to predict who will develop urgency.

VO2 slow component is independent from critical power

The aim of this study was to determine whether the amplitude of the V˙O (2) slow component was dependent from Critical Power (CP; the slope of the linear time - distance relationship) in individuals matched for V˙O (2) peak. 30 moderately-trained endurance athletes completed a maximal graded exercise test, 2 randomly ordered constant power tests at 90 and 100% of peak power output (PPO), and 2 constant duration test of 6 min at 30% of the difference between CP and PPO. Afterwards, participants were ranked according to their relative CP (%PPO; a direct measure of aerobic endurance). The median third was excluded to form a low aerobic endurance group (LEG) and a high aerobic endurance group (HEG). A t-test revealed no difference between LEG and HEG in peak oxygen consumption, but a large difference in their relative CP (p<0.001, effect size=3.2). A' (2) was similar between groups (626 ± 96 and 512 ± 176 ml, corresponding to 26 ± 4 and 24 ± 8% of end exercise oxygen consumption, respectively; NS) and was not associated with relative CP (r=0.10; NS). These results suggest that increasing CP probably extends the range of exercise intensities over which the V˙O (2) slow component does not develop, but does not decrease the amplitude of this phenomenon once it occurs.

Risk factors for encephalitis from West Nile Virus: a matched case-control study using hospitalized controls

We conducted a case-control study to determine risk factors for developing encephalitis among West Nile virus cases when compared with age-, gender and race/ethnicity-matched hospitalized controls. In the multivariable conditional logistic regression analysis, we identified the following independent risk factors associated with being an encephalitis case: hypertension (OR 4.0; P = 0.005), immunosuppressing conditions (OR 5.6; P = 0.001) and cardiovascular disease (OR = 28.3; P < 0.001). Individuals with these comorbidities should be targeted for education on protecting themselves from mosquito exposures.

Evaluation of a radiographer-provided barium enema service

AIM

Radiographers performed and reported 5516 double contrast barium enemas (RDCBEs) over 4 years to October 2001. This study was undertaken to assess the accuracy of RDCBE and the sensitivity for diagnosing colorectal cancer (CRC).

METHOD

A total of 224 consecutive outpatient RDCBEs were reported; normal (C1), diverticulosis (C2), diverticulosis with filling defect (C3), diverticulosis & other pathology (C4) and abnormal (C5). RDCBEs were then reported by a radiologist (AL, NS) and the two reports compared. Of 450 CRCs, 153 had undergone DCBE; 152 RDCBEs. Reports were analysed to establish concurrence between radiographer and radiologist and final CRC diagnosis.

RESULTS

By category: C1 - 37%, C2 - 31%, C3 - 21%, C4 - 11%, C5 - 0%. C4s included polyps (50%), cancer (12.5%), disrupted anastomosis (8%) and colitis (4%). There was no discrepancy between RDCBE and radiologist reports. Radiology and CRC diagnosis agreed in 145 of 152 DCBEs. There were three exclusions: DCBEs occurred outside the study period (2), one only with raised possibility of malignancy. Of eight remaining RDCBEs, seven were false negatives and one false positive. Sensitivity score for RDCBE was 94.5%. Double reporting by a radiologist did not improve sensitivity.

CONCLUSION

RDCBEs are as accurate as those performed by radiologists and have a very high sensitivity for CRC. In a time of ever increasing demands for complex staging investigations for CRC and interventional radiology, the ACPGBI needs to reconsider its guidelines on radiographers not only performing but also reporting DCBE.

Laparoscopic ventral rectopexy, posterior colporrhaphy and vaginal sacrocolpopexy for the treatment of recto-genital prolapse and mechanical outlet obstruction

OBJECTIVE

Whilst trans-abdominal fixation +/- resection offers better functional results and lower recurrence than perineal procedures, mesh rectopexy is complicated by constipation. Laparoscopic autonomic nerve-sparing, ventral rectopexy allows correction of the underlying abnormalities of the rectum, vagina, bladder and pelvic floor.

METHOD

A prospective database was used to audit our 7-year experience of this technique. The recto-vaginal septum was mobilized anteriorly to the pelvic floor avoiding nerve damage. A prolene mesh was sutured to the ventral rectum, posterior vagina and vaginal fornix and secured to the sacral promontory. Patients were assessed with questionnaires and Cleveland Clinic scores.

RESULTS

Eighty patients, six males, median age 59 years (range 31-90) underwent laparoscopic prolapse surgery between Jan 1997 and Dec 2005; 55% had full thickness prolapse and 46% rectal anal intussusception. Five had a solitary rectal ulcer. A total of 58% had undergone previous surgery; hysterectomy 33%, posterior colporrhaphy 15%, posterior rectopexy 6%, Delorme's rectal mucosectomy 5% and Birch colposuspension 3%. Half (54%) were incontinent (mean Wexner score 11, range 2-17) and 31% reported symptoms of obstructed defecation; seven had slow transit constipation and underwent resection. The median operative time was 125 min (range 50-210) with one conversion. Median time to diet was 12 h and median length of stay 3 days (1-12). No patient has developed recurrent full thickness prolapse at a median follow-up of 54 months (30-96). Incontinence improved in 39 of 43 patients (91%); median post-operative Wexner score 1 (0-9). Obstructed defecation resolved in 20 of 25 patients (80%). Pelvic pain resolved in all but one. Complications occurred in 21%; faecal impaction 4%, wound infection 2%, bleeding 2%, leak 1%, chest infection 1%, retention 1%. Three developed minor evacuatory difficulties and two, urinary stress incontinence.

CONCLUSION

Laparoscopic ventral rectopexy is safe with relatively low morbidity. In the medium-term, it provides good results for prolapse and associated symptoms of incontinence and obstructed defecation.

V·O2 Kinetics during Supramaximal Exercise: Relationship with Oxygen Deficit and 800-m Running Performance

The aim of this study was to compare .VO2 kinetics of highly- versus recreationally-trained subjects during a constant velocity test of supramaximal intensity. Eighteen trained male subjects were recruited to one of two groups: highly trained (HT, n = 8, .VO(2max) = 70.1 +/- 6.5 ml . min (-1) . kg (-1)) and recreationally trained (RT, n = 10, .VO(2max) = 63.2 +/- 6.4 ml . min (-1) . kg (-1)). All subjects performed an incremental test to exhaustion for the determination of .VO(2max) and peak treadmill velocity (PTV), two constant velocity tests at 110 % of PTV to determine .VO2 kinetics and oxygen deficit (O(2)def), and a 800-m time trial to determine running performance (mean velocity over the distance, V (800 m)). We found significant differences between HT and RT for the on-transient of the .VO2 response (tau, 24.7 +/- 3.3 and 30.9 +/- 7.0 s, respectively), the amplitude of the .VO2 response (60.0 +/- 5.0 and 53.5 +/- 5.7 ml . min (-1) . kg (-1), respectively) and V (800 m) (6.27 +/- 2.1 and 5.45 +/- 0.38 m . s (-1), respectively). O(2)def (24.6 +/- 2.7 and 27.7 +/- 7.8 ml . kg (-1), respectively) and the gain of the .VO2 response (193 +/- 14 and 194 +/- 13 ml . kg (-1) . m (-1), respectively) were similar between groups. tau was associated with O(2)def (r = 0.90, p < 0.05), but not with V (800 m) (r = 0.30, p > 0.05). It was concluded that HT subjects exhibited faster on-kinetics and higher amplitude than their RT counterparts. The higher amplitude was not thought to reflect any difference in underlying physiological mechanisms. The faster tau, whose exact mechanisms remain to be elucidated, may have practical implications for coaches.

Assessment of Maximal Aerobic Power and Critical Power in a Single 90-s Isokinetic All-Out Cycling Test

The purpose of this study was to establish the validity of a 90-s all-out test for the estimation of maximal oxygen uptake (V.O (2max)) and submaximal aerobic ability as represented by critical power. We hypothesized that the fall in power output by the end of the 90-s all-out test (end power) would represent the exhaustion of anaerobic work capability, and as such, would correspond with the critical power. Sixteen active individuals (mean +/- SD: 30 +/- 6 years; 69.6 +/- 9.9 kg) carried out a series of tests: (i) an incremental ramp test to determine V.O (2max), (ii) three fixed-work rate trials to exhaustion to determine critical power, and (iii) two 90-s all-out tests to measure end power and peak V.O (2). End power (292 +/- 65 W) was related to (r=0.89) but was significantly higher (p<0.01) than critical power (264 +/- 50 W). The mean +/- 95 % limits of agreement (29 +/- 65 W) were too low to use these variables interchangeably. The peak V.O (2) in the 90-s trial was significantly lower than the V.O (2max) (3435 +/- 682 ml x min (-1) vs. 3929 +/- 784 ml x min (-1); p<0.01); mean +/- 95 % limits of agreement was equal to 495 +/- 440 mL x min (-1). The 90-s all-out test cannot, therefore, assess both V.O (2max) and critical power in adult performers. The duration of all-out exercise required to allow V.O (2) to attain its maximum is longer than 90 s.

The distance – time relationship over a century of running Olympic performances: A limit on the critical speed concept

We analyse the evolution of the slope (critical speed) and the y-intercept (anaerobic distance capacity) of the linear distance-time relationship over a century of Olympic running performances. The distance-time relationship of each Olympic Games (1920-2004) was plotted using the performances in the 800-, 1500- and 5000-m track events. Values for critical speed and anaerobic distance capacity were determined by linear modelling. Mean performances for the 800, 1500 and 5000 m were 104.9 +/- 1.5 s (1.4%), 217.2 +/- 2.8 s (1.3%) and 808.9 +/- 18.4 s (2.3%), respectively. Critical speed improved during the first three-quarters of the twentieth century to reach a plateau in 1984. This is in accordance with the literature (Peronnet & Thibault, 1989) and suggests that "human aerobic endurance" has improved within the century (+13.4%) and tends to stabilize. Anaerobic distance capacity was highly variable over the century (coefficient of variation = 9.4%) and did not show a linear improvement over the years as has previously been suggested (Peronnet & Thibault, 1989). This could be due to an artefact in the application of the two-parameter model to only three Olympic performances. A limitation to the use of this linear mathematical model to fit physiological data may have been demonstrated.

Oxygen uptake kinetics during supra VO2max treadmill running in humans

Accurate classification of VO2 kinetics is essential to correctly interpret its control mechanisms. The purpose of this study was to examine VO2 kinetics in severe and supra-maximal intensity running exercise using two modelling techniques. Nine subjects (mean +/- S.D: age, 27 +/- 7 years; mass, 69.8 +/- 9.0 kg; VO2max, 59.1 +/- 1.8 mL x kg x min(-1)) performed a series of "square-wave" exercise transitions to exhaustion at running speeds equivalent to 80% of the difference between the VO2 at LT and VO2max (delta), and at 100%, 110% and 120% VO2max. The VO2 response was modelled with an exponential model and with a semi-logarithmic transformation, the latter assuming a certain steady state VO2. With the exponential model there was a significant reduction in the "gain" of the primary component in supra-maximal exercise (167 +/- 5 mL x kg(-1) x km(-1) at 80% delta to 142 +/- 5 mL x kg(-1) x km(-1) at 120% VO2max, p = 0.005). The time constant of the primary component also reduced significantly with increasing intensity (17.8 +/- 1.1 s at 80% delta to 12.5 +/- 1.2 s at 120% VO2max, p < 0.05). However, in contrast, using the semi-log model, the time constant significantly increased with intensity (30.9 +/- 13.5 s at 80% delta to 72.2 +/- 23.9 s at 120% VO2max, p < 0.05). Not withstanding the need for careful interpretation of mathematically modelled data, these results demonstrate that neither the gain nor the time constant of the VO2 primary component during treadmill running are invariant across the severe and supra-maximal exercise intensity domains when fit with an exponential model. This suggests the need for a reappraisal of the VO2/work rate relationship in running exercise.