Impact of a positive crossmatch on pediatric heart transplant outcomes

BACKGROUND

Pediatric heart transplant (HT) candidates experience high waitlist mortality due to a limited donor pool that is constrained in part by anti-HLA sensitization. We evaluated the impact of CDC and Flow donor-specific crossmatch (XM) results on pediatric HT outcomes.

METHODS

All pediatric HTs between 1999 and 2019 in the OPTN database were included. Donor-specific XM results were sub-categorized based on CDC and Flow results. Primary outcomes were treated rejection in the first year and time to death or allograft loss. Propensity scores were utilized to adjust for differences in baseline characteristics.

RESULTS

A total of 4,695 pediatric HT patients with T-cell XM data were included. After propensity score adjustment, a positive T-cell CDC-XM was associated with 2 times higher odds of treated rejection (OR 2.29 (1.56, 3.37)) and shorter time to death/allograft loss (HR 1.50 (1.19, 1.88)) compared to a negative Flow-XM. HT recipients who were Flow-XM positive with negative/unknown CDC-XM did not have higher odds of rejection or shorter time to death/allograft loss. An isolated positive B-cell XM was also not associated with worse outcomes. Over the study period XM testing shifted from CDC- to Flow-based assays.

CONCLUSIONS

A positive donor-specific T-cell CDC-XM was associated with rejection and death/allograft loss following pediatric HT. This association was not observed with a positive T-cell Flow-XM or B-cell XM result alone. The shift away from performing the CDC-XM may result in loss of important prognostic information unless the clinical relevance of quantitative Flow-XM results on heart transplant outcomes is systematically studied.

Development and validation of a multivariable prediction model in pediatric liver transplant patients for predicting intensive care unit length of stay

BACKGROUND

Liver transplantation is the life-saving treatment for many end-stage pediatric liver diseases. The perioperative course, including surgical and anesthetic factors, have an important influence on the trajectory of this high-risk population. Given the complexity and variability of the immediate postoperative course, there would be utility in identifying risk factors that allow prediction of adverse outcomes and intensive care unit trajectories.

AIMS

The aim of this study was to develop and validate a risk prediction model of prolonged intensive care unit length of stay in the pediatric liver transplant population.

METHODS

This is a retrospective analysis of consecutive pediatric isolated liver transplant recipients at a single institution between April 1, 2013 and April 30, 2020. All patients under the age of 18 years receiving a liver transplant were included in the study (n = 186). The primary outcome was intensive care unit length of stay greater than 7 days.

RESULTS

Recipient and donor characteristics were used to develop a multivariable logistic regression model. A total of 186 patients were included in the study. Using multivariable logistic regression, we found that age < 12 months (odds ratio 4.02, 95% confidence interval 1.20-13.51, p = .024), metabolic or cholestatic disease (odds ratio 2.66, 95% confidence interval 1.01-7.07, p = .049), 30-day pretransplant hospital admission (odds ratio 8.59, 95% confidence interval 2.27-32.54, p = .002), intraoperative red blood cells transfusion >40 mL/kg (odds ratio 3.32, 95% confidence interval 1.12-9.81, p = .030), posttransplant return to the operating room (odds ratio 11.45, 95% confidence interval 3.04-43.16, p = .004), and major postoperative respiratory event (odds ratio 32.14, 95% confidence interval 3.00-343.90, p < .001) were associated with prolonged intensive care unit length of stay. The model demonstrates a good discriminative ability with an area under the receiver operative curve of 0.888 (95% confidence interval, 0.824-0.951).

CONCLUSIONS

We develop and validate a model to predict prolonged intensive care unit length of stay in pediatric liver transplant patients using risk factors from all phases of the perioperative period.

Contemporary outcomes of pediatric cardiac transplantation with a positive retrospective crossmatch

BACKGROUND

A positive crossmatch (+ XM) has traditionally been associated with adverse outcomes following pediatric heart transplantation. However, more recent studies suggest that favorable intermediate-term outcomes may be achieved despite a + XM. This study's hypothesis is that children with a + XM have similar long-term survival, but higher rate of complications such as rejection, coronary allograft vasculopathy (CAV), and infection, compared to patients with a negative (-) XM.

METHODS

The Pediatric Heart Transplant Society Registry (PHTS) database was queried from 2010-2021 for all patients <18 years of age with a known XM. Baseline demographics were compared between + XM and - XM groups using appropriate parametric and non-parametric group comparisons. Cox Proportional Hazards Modeling was used to identify risk factors for post-transplant graft loss, rejection, and CAV.

RESULTS

Of 4599 pediatric heart transplants during the study period, XM results were available for 3914 (85%), of which 373 (9.5%) had a + XM. Univariate analysis showed lower 10-year survival for patients with + XM (HR = 1.3, p = .04). Multivariate analyses revealed no significant difference in 10-year survival in the 2 groups; however, time to first rejection (p = .0001) remained significantly shorter in the + XM group.

CONCLUSIONS

Pediatric patients transplanted across a + XM experience earlier rejection; however, after multivariate adjustment, + XM is not independently associated with intermediate-term graft loss. The risk of heart transplantation against a + XM must be balanced with the ongoing risk of waitlist mortality.

Integration of population-level data sources into an individual-level clinical prediction model for dengue virus test positivity

The differentiation of dengue virus (DENV) infection, a major cause of acute febrile illness in tropical regions, from other etiologies, may help prioritize laboratory testing and limit the inappropriate use of antibiotics. While traditional clinical prediction models focus on individual patient-level parameters, we hypothesize that for infectious diseases, population-level data sources may improve predictive ability. To create a clinical prediction model that integrates patient-extrinsic data for identifying DENV among febrile patients presenting to a hospital in Thailand, we fit random forest classifiers combining clinical data with climate and population-level epidemiologic data. In cross validation, compared to a parsimonious model with the top clinical predictors, a model with the addition of climate data, reconstructed susceptibility estimates, force of infection estimates, and a recent case clustering metric, significantly improved model performance.

Health Help-Seeking Behaviour in Spiritual Healing Practice: Records from the Panacea Society's Healing Department, 1924-1997

Why people seek help is a question shared by both health psychologists and scholars of spiritual healing. This overlap, however, has gone unexplored. This article shows convergence between health help-seeking behaviours in spiritual healing and secular professional health services. It does so by drawing on the archival records from the Panacea Society in Bedford, England, which began an international healing ministry by post-amassing over 120,000 correspondents from 93 different countries. Archives from the Panacea Society's Healing Department containing records of the self-reported effects of the prescribed water-taking healing ritual were used to investigate variables related to help-seeking for health problems through spiritual healing. A sample of over 10% of the available records (n = 7192) contained data from 40,627 letters written over a 73-year period from 48 different countries. In line with research from health psychology, and specifically the Health Belief Model, findings showed that those who were older, female, and receiving perceived benefits from treatment were more likely to engage in help-seeking.

Pediatric heart transplant waiting times in the United States since the 2016 allocation policy change

We describe waiting times for pediatric heart transplant (HT) candidates after the 2016 revision to the US allocation policy. The OPTN database was queried for pediatric HT candidates listed between 7/2016 and 4/2019. Of the 1789 included candidates, 65% underwent HT, 14% died/deteriorated, 8% were removed for improvement, and 13% were still waiting at the end of follow-up. Most candidates were status 1A at HT (81%). Median wait times differ substantially by listing status, blood type, and recipient weight. The likelihood of HT was lower in candidates <25 kg and in those with blood type O; The <25 kg, blood type O subgroup experiences longer wait times and higher wait list mortality. For status 1A candidates, median wait times were 108 days (≤25 kg, blood type O), 80 days (≤25 kg, non-O), 47 days (>25 kg, O), and 24 days (>25 kg, non-O). We found that centers with more selective organ acceptance practices, based on a lower median Pediatric Heart Donor Assessment Tool (PH-DAT) score for completed transplants, experience longer status 1A wait times for their listed patients. These data can be used to counsel families and to select appropriate advanced heart failure therapies to support patients to transplant.

Design and Implementation of a novel Weekend Elective Paediatric Surgery Program to Reduce COVID-19 Related Backlog: Operating Room Ramp-Up After COVID-19 Lockdown Ends - Extra Lists (ORRACLE-Xtra)

Background

The COVID-19 pandemic caused by the SARS-COV-2 virus has resulted in unprecedented challenges for the health care system. A decrease of surgical services led to substantial backlogs for time-sensitive scheduled pediatric patients. We designed and implemented a novel pilot weekend surgical quality improvement project called Operating Room Ramp-Up After COVID Lockdown Ends—Extra Lists (ORRACLE-Xtra).

Objective

Our overall goals are to increase patient access to surgery (and reduce the wait list), improve operating room efficiencies, and optimize parent and staff experience.

Methods

Using the DMAIC (define, measure, analyze, improve, control) framework, we implemented ORRACLE-Xtra in a tertiary care academic pediatric hospital during a quiescent period of the COVID-19 pandemic. We defined process and outcome measures based on provincial targets of out-of-window cases. Parental and staff satisfaction was tracked by surveys.

Results

ORRACLE-Xtra led to 247 patients receiving surgery during the pilot period, resulting in a 5% decrease in the total number of patients on our wait list with Paediatric Canadian Access Targets for Surgery IV (147/247, 59.5%), with 38.1% (94/247) out-of-window of provincial targets. Most of the process and outcome measures were met or exceeded. Overall parental satisfaction was at 95.8% (110/121), with 79% (64/81) of staff reporting satisfaction with working weekends.

Conclusions

Through the ORRACLE-Xtra pilot program, we have shown that hospitals impacted by COVID-19 can reduce the surgical backlog using innovative models of service delivery in a Canadian context. Sustained funding is critical to achieving more meaningful reductions in wait times for scheduled surgeries over the longer term and needs to be balanced with staff well-being.

The state of adoption of anesthesia information management systems in Canadian academic anesthesia departments: a survey

PURPOSE

Anesthesia information management systems (AIMS) are gradually replacing paper documentation of anesthesia care. This study sought to determine the current status of AIMS adoption and the level of health informatics expertise in Canadian academic anesthesia departments.

METHODS

Department heads or their designates of Canadian academic anesthesia departments were invited by e-mail to complete an online survey between September 2019 and February 2020. The survey elicited information on current AIMS or future plans for an AIMS installation, the number of department members dedicated to clinical informatics issues, the gross level of health informatics expertise at each department, perceived advantages of AIMS, and perceived disadvantages of and barriers to implementation of AIMS.

RESULTS

Of the 64 departments invited to participate, 63 (98.4%) completed the survey. Only 21 (33.3%) of the departments had AIMS. Of the 42 departments still charting on paper, 23 (54.8%) reported planning to install an AIMS within the next five years. Forty-six departments (73%) had at least one anesthesiologist tasked with dealing with AIMS or electronic health record issues. Most reported having no department members with extensive knowledge or formal training in health informatics. The top three perceived barriers and disadvantages to an AIMS installation were its initial cost, lack of funding, and a lack of technical support dedicated specifically to AIMS. The top three advantages departments wished to prioritize with AIMS were accurate clinical documentation, better data for quality improvement initiatives, and better data for research.

CONCLUSIONS

A majority of Canadian academic anesthesia departments are still using paper records, but this trend is expected to reverse in the next five years as more departments install an AIMS. Health informatics expertise is lacking in most of the departments, with a minority planning to support the training of future anesthesia informaticians.

Online education in a hurry: Delivering pediatric graduate medical education during COVID-19

In the setting of the coronavirus disease 2019 (COVID-19) pandemic, an emergency hospital-wide eWork policy was enacted at Boston Children's Hospital on March 16, 2020. The number of clinicians on campus was restricted to only essential personnel, guidelines limited clinical care delivery to solely non-elective patients, and strict maximums were placed on the numbers of people allowed to congregate in the same physical space. With this abrupt transition to social distancing and electronic communication, the established approach to educating graduate medical trainees became obsolete overnight. Anticipating significant impact on trainee and faculty professional and personal lives, the importance of adaptive teaching strategies was evident. This document details one approach to redesigning the clinical learning system including a description of the learners and environment, the pedagogical principles that guided the approach, and technological tools used in implementation. Additionally, available literature pertinent to this topic is explored, assessment of the work to date is presented, and suggestions are provided regarding future directions related to online graduate medical education.

Current evaluation and management of plastic bronchitis in the pediatric population

OBJECTIVE

To describe a multidisciplinary approach for the treatment of plastic bronchitis (PB) in children.

METHODS

Retrospective chart review of children with PB between 1997 and 2017. Data regarding clinical presentation, diagnosis, management, and outcomes were analyzed.

RESULTS

Of 34 patients presenting with PB, 24 had single ventricle (SV) heart disease, 9 had pulmonary disease, and one had no underlying disease. Median (IQR: interquartile range) age at the time of PB diagnosis was 5.5 years (IQR: 9.0). Presenting symptoms included cough productive of casts (n = 27, 79%), wheezing (n = 5, 15%), dyspnea (n = 18, 53%), hypoxia (n = 31, 91%), and respiratory failure (n = 9, 26%). Diagnosis was made based on clinical evaluation, bronchoscopy findings, and/or pathology of casts. Treatment methods included bronchoscopy for cast removal (25% of SV patients, 91% of non-SV patients), chest physiotherapy (SV: 92%, non-SV: 45%), albuterol (SV: 79%, non-SV: 73%), inhaled steroids (SV: 75%, non-SV: 18%), nebulized hypertonic saline (SV: 29%, non-SV: 9%), nebulized heparin (SV: 8%, non-SV: 55%), nebulized tissue plasminogen activator (tPA; SV: 33%, non-SV: 9%), inhaled Dornase Alfa (SV: 54%, non-SV: 9%), antibiotics (SV: 46%, non-SV: 45%), systemic steroids (SV: 13%, non-SV: 45%), and lymphatic embolization (SV: 8%, non-SV: 45%). Of SV patients, 11 had no recurrence, 5 underwent heart transplantation, one awaits transplant, and 3 died due to cardiac disease. Three patients with respiratory disease had recurrent PB and one died from MRSA pneumonia.

CONCLUSION

PB is a highly morbid disease with limited treatment options. Bronchoscopy and chest physiotherapy for airway clearance are among the most-utilized therapies.

Applications of novel bioreactor technology to enhance the viability and function of cultured cells and tissues

As the field of tissue engineering continues to advance rapidly, so too does the complexity of cell culture techniques used to generate in vitro tissue constructs, with the overall aim of mimicking the in vivo microenvironment. This complexity typically comes at a cost with regards to the size of the equipment required and associated expenses. We have developed a small, low-cost bioreactor system which overcomes some of the issues of typical bioreactor systems while retaining a suitable scale for the formation of complex tissues. Herein, we have tested this system with three cell populations/tissues: the culture of hepatocellular carcinoma cells, where an improved structure and basic metabolic function is seen; the culture of human pluripotent stem cells, in which the cultures can form more heterogeneous tissues resembling the in vivo teratoma and ex vivo liver tissue slices, in which improved maintenance of cellular viability is seen over the 3 days tested. This system has the flexibility to be used for a variety of further uses and has the potential to provide a more accessible alternative to current bioreactor technologies.

Integrating the underlying structure of stochasticity into community ecology

Stochasticity is a core component of ecology, as it underlies key processes that structure and create variability in nature. Despite its fundamental importance in ecological systems, the concept is often treated as synonymous with unpredictability in community ecology, and studies tend to focus on single forms of stochasticity rather than taking a more holistic view. This has led to multiple narratives for how stochasticity mediates community dynamics. Here, we present a framework that describes how different forms of stochasticity (notably demographic and environmental stochasticity) combine to provide underlying and predictable structure in diverse communities. This framework builds on the deep ecological understanding of stochastic processes acting at individual and population levels and in modules of a few interacting species. We support our framework with a mathematical model that we use to synthesize key literature, demonstrating that stochasticity is more than simple uncertainty. Rather, stochasticity has profound and predictable effects on community dynamics that are critical for understanding how diversity is maintained. We propose next steps that ecologists might use to explore the role of stochasticity for structuring communities in theoretical and empirical systems, and thereby enhance our understanding of community dynamics.

Sporadic Genetic Connectivity among Small Insular Populations of the Rare Geoendemic Plant Caulanthus amplexicaulis var. barbarae (Santa Barbara Jewelflower)

Globally, a small number of plants have adapted to terrestrial outcroppings of serpentine geology, which are characterized by soils with low levels of essential mineral nutrients (N, P, K, Ca, Mo) and toxic levels of heavy metals (Ni, Cr, Co). Paradoxically, many of these plants are restricted to this harsh environment. Caulanthus ampexlicaulis var. barbarae (Brassicaceae) is a rare annual plant that is strictly endemic to a small set of isolated serpentine outcrops in the coastal mountains of central California. The goals of the work presented here were to 1) determine the patterns of genetic connectivity among all known populations of C. ampexlicaulis var. barbarae, and 2) estimate contemporary effective population sizes (Ne), to inform ongoing genomic analyses of the evolutionary history of this taxon, and to provide a foundation upon which to model its future evolutionary potential and long-term viability in a changing environment. Eleven populations of this taxon were sampled, and population-genetic parameters were estimated using 11 nuclear microsatellite markers. Contemporary effective population sizes were estimated using multiple methods and found to be strikingly small (typically Ne < 10). Further, our data showed that a substantial component of genetic connectivity of this taxon is not at equilibrium, and instead showed sporadic gene flow. Several lines of evidence indicate that gene flow between isolated populations is maintained through long-distance seed dispersal (e.g., >1 km), possibly via zoochory.

Lead alters intracellular protein signaling and suppresses pro-inflammatory activation in TLR4 and IFNR-stimulated murine RAW 264.7 cells, in vitro

Lead (Pb) is a persistent environmental pollutant that has a structure and charge similar to many ions, such as calcium, that are essential for normal cellular function. Pb may compete with calcium for protein binding sites and inhibit signaling pathways within the cell affecting many organ systems including the immune system. The aim of the current study was to assess whether the calcium/calmodulin pathway is a principal target of environmentally relevant Pb during pro-inflammatory activation in a RAW 264.7 macrophage cell line. RAW 264.7 cells were cultured with 5 μM Pb(NO₃)₂, LPS, rIFNγ, or LPS+rIFNγ for 12, 24, or 48 hr. Intracellular protein signaling and multiple functional endpoints were investigated to determine Pb-mediated effects on macrophage function. Western blot analysis revealed that Pb initially modulated nuclear localization of NFκB p65 and cytoplasmic phosphorylation of CaMKIV accompanied by increased phosphorylation of STAT1β at 24 hr. Macrophage proliferation was significantly decreased at 12 hr in the presence of Pb, while nitric oxide (NO) was significantly reduced at 12 and 24 hr. Cells cultured with Pb for 12, 24, or 48 hr exhibited altered cytokine levels after specific stimuli activation. Our findings are in agreement with previous reports suggesting that macrophage pro-inflammatory responses are significantly modulated by Pb. Further, Pb-induced phosphorylation of CaMKIV (pCaMKIV), observed in the present study, may be a contributing factor in metal-induced autophagy noted in our previous study with this same cell line.

Fidaxomicin versus oral vancomycin for severe Clostridium difficile infection: a retrospective cohort study

OBJECTIVES

This study was conducted to compare clinical outcomes of fidaxomicin versus oral vancomycin in the management of severe Clostridium difficile infection (CDI).

METHODS

The investigation was a retrospective, multicentre, propensity score-matched analysis using a national clinical administrative database. Veterans treated for severe CDI from any Veterans Affairs Medical Center between 1 June 2011 and 30 June 2017 were included if they received fidaxomicin or an oral vancomycin regimen for treatment. The two groups were matched by the nearest-neighbour method from a propensity score derived from independent variables associated with the selection of a fidaxomicin course.

RESULTS

Propensity score matching resulted in two well-matched cohorts consisting of 213 fidaxomicin and 639 oral vancomycin courses. No statistically-significant difference was found for the primary outcome of combined clinical failure or recurrence (68/213 (31.9%) versus 163/639 (25.5%), respectively, p 0.071). Additionally, no statistically significant differences were found for the secondary outcomes of 30-day (23/213 (10.8%) versus 75/639 (11.7%), respectively, p 0.71), 90-day (48/213 (22.5%) versus 140/639 (21.9%), respectively, p 0.85), and 180-day mortality (62/213 (29.1%) versus 186/639 (29.1%), respectively, p 1.0) between the two treatment groups.

CONCLUSIONS

Courses of fidaxomicin or oral vancomycin for severe CDI resulted in similar treatment outcomes. Study findings are consistent with current treatment guideline recommendations for the use of either agent in the management of severe CDI.

The new subversive geranium: some notes on the management of additional troubles in maximum security prisons

In this paper, we revisit King and McDermott's 1990 article on the social construction of 'control problem' prisoners and their management in high security prisons, in the light of our recent research on the location and building of trust in contemporary high security prisons. We examine how religious and race identities are now deeply implicated in the construction of risk, and we describe the procedures for and some of the consequences of managing the new risks of radicalization and extremist violence in prison. The analysis is based on observations and interviews with staff and prisoners in two main and two supplementary maximum-security prisons in England and Wales.

Portable Automation of Static Chamber Sample Collection for Quantifying Soil Gas Flux

Quantification of soil gas flux using the static chamber method is labor intensive. The number of chambers that can be sampled is limited by the spacing between chambers and the availability of trained research technicians. An automated system for collecting gas samples from chambers in the field would eliminate the need for personnel to return to the chamber during a flux measurement period and would allow a single technician to sample multiple chambers simultaneously. This study describes hamber utomated ampling quipment (Flux) to collect and store chamber headspace gas samples at assigned time points for the measurement of soil gas flux. The FluxCASE design and operation is described, and the accuracy and precision of the FluxCASE system is evaluated. In laboratory measurements of nitrous oxide (NO), carbon dioxide (CO), and methane (CH) concentrations of a standardized gas mixture, coefficients of variation associated with automated and manual sample collection were comparable, indicating no loss of precision. In the field, soil gas fluxes measured from FluxCASEs were in agreement with manual sampling for both NO and CO. Slopes of regression equations were 1.01 for CO and 0.97 for NO. The 95% confidence limits of the slopes of the regression lines included the value of one, indicating no bias. Additionally, an expense analysis found a cost recovery ranging from 0.6 to 2.2 yr. Implementing the FluxCASE system is an alternative to improve the efficiency of the static chamber method for measuring soil gas flux while maintaining the accuracy and precision of manual sampling.

Divergent responses of viral and bacterial communities in the gut microbiome to dietary disturbances in mice

To improve our understanding of the stability of mammalian intestinal communities, we characterized the responses of both bacterial and viral communities in murine fecal samples to dietary changes between high- and low-fat (LF) diets. Targeted DNA extraction methods for bacteria, virus-like particles and induced prophages were used to generate bacterial and viral metagenomes as well as 16S ribosomal RNA amplicons. Gut microbiome communities from two cohorts of C57BL/6 mice were characterized in a 6-week diet perturbation study in response to high fiber, LF and high-refined sugar, milkfat (MF) diets. The resulting metagenomes from induced bacterial prophages and extracellular viruses showed significant overlap, supporting a largely temperate viral lifestyle within these gut microbiomes. The resistance of baseline communities to dietary disturbances was evaluated, and we observed contrasting responses of baseline LF and MF bacterial and viral communities. In contrast to baseline LF viral communities and bacterial communities in both diet treatments, baseline MF viral communities were sensitive to dietary disturbances as reflected in their non-recovery during the washout period. The contrasting responses of bacterial and viral communities suggest that these communities can respond to perturbations independently of each other and highlight the potentially unique role of viruses in gut health.

Impact of climate change and population growth on a risk assessment for endocrine disruption in fish due to steroid estrogens in England and Wales

In England and Wales, steroid estrogens: estrone, estradiol and ethinylestradiol have previously been identified as the main chemicals causing endocrine disruption in male fish. A national risk assessment is already available for intersex in fish arising from estrogens under current flow conditions. This study presents, to our knowledge, the first set of national catchment-based risk assessments for steroid estrogen under future scenarios. The river flows and temperatures were perturbed using three climate change scenarios (ranging from relatively dry to wet). The effects of demographic changes on estrogen consumption and human population served by sewage treatment works were also included. Compared to the current situation, the results indicated increased future risk:the percentage of high risk category sites, where endocrine disruption is more likely to occur, increased. These increases were mainly caused by changes in human population. This study provides regulators with valuable information to prepare for this potential increased risk.

Exploiting monitoring data in environmental exposure modelling and risk assessment of pharmaceuticals

In order to establish the environmental impact of an active pharmaceutical ingredient (API), good information on the level of exposure in surface waters is needed. Exposure concentrations are typically estimated using information on the usage of an API as well as removal rates in the patient, the wastewater system and in surface waters. These input data are often highly variable and difficult to obtain, so model estimates often do not agree with measurements made in the field. In this paper we present an approach which uses inverse modelling to estimate overall removal rates of pharmaceuticals at the catchment scale using a hydrological model as well as prescription and monitoring data for a few representative sites for a country or region. These overall removal rates are then used to model exposure across the broader landscape. Evaluation of this approach for APIs in surface waters across England and Wales showed good agreement between modelled exposure distributions and available monitoring data. The use of the approach, alongside estimates of predicted no-effect concentrations for the 12 study compounds, to assess risk of the APIs across the UK landscape, indicated that, for most of the compounds, risks to aquatic life were low. However, ibuprofen was predicted to pose an unacceptable risk in 49.5% of the river reaches studied. For diclofenac, predicted exposure concentrations were also compared to the Environmental Quality Standard previously proposed by the European Commission and 4.5% of river reaches were predicted to exceed this concentration. While the current study focused on pharmaceuticals, the approach could also be valuable in assessing the risks of other 'down the drain' chemicals and could help inform our understanding of the important dissipation processes for pharmaceuticals in the pathway from the patient to ecological receptors.

Plant diversity predicts beta but not alpha diversity of soil microbes across grasslands worldwide

Aboveground-belowground interactions exert critical controls on the composition and function of terrestrial ecosystems, yet the fundamental relationships between plant diversity and soil microbial diversity remain elusive. Theory predicts predominantly positive associations but tests within single sites have shown variable relationships, and associations between plant and microbial diversity across broad spatial scales remain largely unexplored. We compared the diversity of plant, bacterial, archaeal and fungal communities in one hundred and forty-five 1 m(2) plots across 25 temperate grassland sites from four continents. Across sites, the plant alpha diversity patterns were poorly related to those observed for any soil microbial group. However, plant beta diversity (compositional dissimilarity between sites) was significantly correlated with the beta diversity of bacterial and fungal communities, even after controlling for environmental factors. Thus, across a global range of temperate grasslands, plant diversity can predict patterns in the composition of soil microbial communities, but not patterns in alpha diversity.

Demonstrating microbial co-occurrence pattern analyses within and between ecosystems

Co-occurrence patterns are used in ecology to explore interactions between organisms and environmental effects on coexistence within biological communities. Analysis of co-occurrence patterns among microbial communities has ranged from simple pairwise comparisons between all community members to direct hypothesis testing between focal species. However, co-occurrence patterns are rarely studied across multiple ecosystems or multiple scales of biological organization within the same study. Here we outline an approach to produce co-occurrence analyses that are focused at three different scales: co-occurrence patterns between ecosystems at the community scale, modules of co-occurring microorganisms within communities, and co-occurring pairs within modules that are nested within microbial communities. To demonstrate our co-occurrence analysis approach, we gathered publicly available 16S rRNA amplicon datasets to compare and contrast microbial co-occurrence at different taxonomic levels across different ecosystems. We found differences in community composition and co-occurrence that reflect environmental filtering at the community scale and consistent pairwise occurrences that may be used to infer ecological traits about poorly understood microbial taxa. However, we also found that conclusions derived from applying network statistics to microbial relationships can vary depending on the taxonomic level chosen and criteria used to build co-occurrence networks. We present our statistical analysis and code for public use in analysis of co-occurrence patterns across microbial communities.

Melody valve implant within failed bioprosthetic valves in the pulmonary position: a multicenter experience

BACKGROUND

Transcatheter pulmonary valve implantation using the Melody valve has emerged as an important therapy for the treatment of postoperative right ventricular outflow tract dysfunction. Melody-in-bioprosthetic valves (BPV) is currently considered an off-label indication. We review the combined experience with transcatheter pulmonary valve implantation within BPVs from 8 centers in the United States and discuss technical aspects of the Melody-in-BPV procedure.

METHODS AND RESULTS

A total of 104 patients underwent Melody-in-BPV in the pulmonary position at 8 US centers from April 2007 to January 2012. Ten different types of BPVs were intervened on, with Melody valve implantation at the intended site in all patients. Following Melody valve implant, the peak right ventricle-to-pulmonary artery gradient decreased from 38.7 ± 16.3 to 10.9 ± 6.7 mm Hg (P<0.001), and the right ventricular systolic pressure fell from 71.6 ± 21.7 to 46.7 ± 15.9 mm Hg (P<0.001). There was no serious procedural morbidity, and no deaths related to the catheterization or implant. At a median follow-up of 12 months (1-46 months), no patients had more than mild regurgitation, and 4 had a mean right ventricular outflow tract gradient ≥30 mm Hg. During follow-up, there were 2 stent fractures, 3 cases of endocarditis (2 managed with surgical explant), and 2 deaths that were unrelated to the Melody valve.

CONCLUSIONS

Transcatheter pulmonary valve implantation using the Melody valve within BPVs can be accomplished with a high rate of success, low procedure-related morbidity and mortality, and excellent short-term results. The findings of this preliminary multicenter experience suggest that the Melody valve is an effective transcatheter treatment option for failed BPVs.

Usefulness of serum brain natriuretic peptide to predict adverse events in patients with the Eisenmenger syndrome

The aim of this study was to evaluate the prognostic value of brain natriuretic peptide (BNP) in outpatients with the Eisenmenger syndrome (ES). BNP is often elevated in patients with cyanotic congenital heart disease. The clinical utility of BNP in patients with cyanotic congenital heart disease and the ES has not been clearly delineated. Records of adults with ES who had undergone serum BNP measurement were reviewed. The primary end point was death or heart failure admission. Fifty-three patients were included, with 15 patients (28%) meeting the primary end point (death in 7, heart failure hospitalization in 8). Mean and median baseline BNP in patients meeting the primary end point were 322 ± 346 and 179 pg/ml, compared to 100 ± 157 and 41 pg/ml in those not meeting the primary end point (p = 0.0029). A Cox proportional-hazards model using baseline BNP between the 2 groups yielded a hazard ratio of 1.84 (95% confidence interval [CI] 1.19 to 2.85, p = 0.006). The relative risk for baseline BNP level >140 pg/ml was 4.62 (95% CI 1.80 to 11.3, p = 0.008). Patients who met the primary end point increased their BNP levels by 42.5 pg/ml per year (95% CI 12.09 to 72.95, p = 0.006) compared to 7.2 pg/ml per year (95% CI 2.01 to 12.47, p = 0.007) in patients who did not meet the primary end point. In conclusion, elevated BNP levels are predictive of death or heart failure admission in patients with the ES. A serum BNP level >140 pg/ml is a useful tool in identifying high-risk patients.

Disordered gambling among higher-frequency gamblers: who is at risk?

BACKGROUND

When gambling opportunities are made available to the public in a given jurisdiction, some individuals participate occasionally and others more frequently. Among frequent gamblers, some individuals develop problematic involvement and some do not. This study addresses the association among demographic and social risk factors, frequency of gambling and gambling disorders.

METHOD

Data from an adult community sample (n=1372) were used to identify risk factors for higher-frequency gambling and disordered gambling involvement.

RESULTS

Individuals with higher intelligence, older individuals and more religious individuals were less frequent gamblers. Males, single individuals and those exposed to gambling environments (friends and family who gamble) and those who started to gamble at a younger age were more frequent gamblers. Excitement-seeking personality traits were also higher among more frequent gamblers. A different set of risk factors was associated with the likelihood of gambling disorder among these higher-frequency gamblers. These variables included mental health indicators, childhood maltreatment and parental gambling involvement. Among higher-frequency gamblers, individuals who smoke cigarettes, those with a diagnosis of alcohol or drug dependence or obsessive-compulsive disorder, those with higher anxiety or depression and those with higher impulsivity and antisocial personality traits were more likely to report gambling-related problems. These individuals were also more likely to report gambling on electronic gambling machines (e.g. slot machines).

CONCLUSIONS

These data suggest a model in which higher-frequency gambling, particularly with electronic gambling machines, when combined with any type of emotional vulnerability increased the likelihood of gambling disorder.

Wildfires, fuel treatment and risk mitigation in Australian eucalypt forests: insights from landscape-scale simulation

Wildfires pose significant risks to people and human infrastructure worldwide. The treatment of fuel in landscapes may alter these risks but the magnitude of this effect on risk is poorly understood. Evidence from Australian Eucalyptus forests suggests that mitigation of risk using prescribed burning as a fuel treatment is partial because weather and fuel dynamics are conducive to regular high intensity fires. We further examine the response of risk to treatment in eucalypt forests using landscape simulation modelling. We model how five key measures of wildfire activity that govern risk to people and property may respond to variations in rate and spatial pattern of prescribed fire. We then model effects of predicted climate change (2050 scenarios) to determine how the response of risk to treatment is likely to be altered in the future. The results indicate that a halving of risk to people and property in these forests is likely to require treatment rates of 7-10% of the area of the landscape per annum. Projections of 2050 weather conditions under climate change further substantially diminished the effect of rate of treatment. A large increase in rates of treatment (i.e. circa. 50% over current levels) would be required to counteract these effects of climate change. Such levels of prescribed burning are unlikely to be financially feasible across eucalypt dominated vegetation in south eastern Australia. Despite policy imperatives to expand fuel treatment, a reduction rather than an elimination of risk will result. Multi-faceted strategies will therefore be required for the management of risk.

Estimating surface water concentrations of "down-the-drain" chemicals in China using a global model

Predictions of surface water exposure to "down-the-drain" chemicals are presented which employ grid-based spatially-referenced data on average monthly runoff, population density, country-specific per capita domestic water and substance use rates and sewage treatment provision. Water and chemical load are routed through the landscape using flow directions derived from digital elevation data, accounting for in-stream chemical losses using simple first order kinetics. Although the spatial and temporal resolution of the model are relatively coarse, the model still has advantages over spatially inexplicit "unit-world" approaches, which apply arbitrary dilution factors, in terms of predicting the location of exposure hotspots and the statistical distribution of concentrations. The latter can be employed in probabilistic risk assessments. Here the model was applied to predict surface water exposure to "down-the-drain" chemicals in China for different levels of sewage treatment provision. Predicted spatial patterns of concentration were consistent with observed water quality classes for China.

Significant neurological presentations in commando trained personnel: case studies and consideration of differential diagnosis

A 27-year-old Royal Marine presented to his sickbay following two episodes of sudden onset visual disturbance. A subsequent MRI Scan demonstrated ischaemic changes in the territory of his right posterior cerebral artery. Transthoracic echocardiography was normal but a bubble contrast study was strongly positive indicating the presence of a relatively large patent foramen ovale (PFO). He underwent endovascular closure of his patent foramen ovale and was subsequently upgraded back to full duties. A 35-year-old Army Sergeant presented with sudden onset collapse, right sided weakness, dysarthria and confusion. He was airlifted to a Host Nation hospital and following a normal CT head underwent thrombolysis in the Emergency Department. This was unsuccessful but a CT guided embolectomy led to complete resolution of symptoms. Subsequent transthoracic echo revealed a PFO. He underwent endovascular closure and has since been returned to full duties. The incidence of PFO is common affecting 27% of the population but the incidence of ischaemic stroke in young adults (aged 15-45 years old) is rare. This maybe linked to the size of the PFOs in symptomatic individuals. These case reports emphasise the requirement for further investigation of individuals presenting with collapse and persisting neurology. Differential diagnosis and initial management for primary care and pre-hospital clinicians is also reviewed.

Performance in concurrent interval schedules

Four pigeons were trained under concurrent variable-interval variable-interval and fixed-interval variable-interval schedules in a two-key situation. Both response allocation and time allocation to the two schedules were measured when various reinforcement rates were arranged on each key. All animals showed an approximately constant proportional preference for the variable-interval schedule over the fixed-interval schedule. These results support Schneider's (1969) analysis of fixed-interval schedule performance.

THE EFFECTS OF PANTOTHENIC ACID ON RESPIRATORY ACTIVITY

Experiments using the Warburg-Barcroft apparatus led to the following results and conclusions: (1) Two yeasts in three different media were strikingly stimulated in their respiration by minute amounts of pantothenic acid. (2) Nine other compounds (vitamins and other biologically important substances) were tested and found in all cases to have on the deficient G.M. yeast, lesser and in some cases no appreciable stimulative effect. Thiamin was the most effective of these compounds. Its action was shown to be different and in some ways antagonistic to that of pantothenic acid. (3) Liver extract (Lilly's Number 343) contains substances capable of speeding up respiration (and growth) to a much higher level than seems possible with known compounds. (4) Pantothenic acid was found to have a definite stimulative effect on fermentation by dialyzed maceration juice from yeast. (5) It likewise stimulated respiration of apple and potato tissue and indications of a similar effect on certain animal tissues were obtained.

Heart rate responses during acclimation of horses to water treadmill exercise

REASONS FOR PERFORMING STUDY

The use of water treadmill exercise in horses is popular, although little is known about the physiological responses to this form of exercise. No information exists regarding the time taken to acclimate to water treadmill exercise compared to that of high-speed treadmill exercise, for both physiological and biomechanical parameters.

OBJECTIVE

To determine heart rate responses during acclimation to water treadmill exercise with and without sedation on first time exposure.

METHODS

All horses were exercised on a water treadmill at the walk for 15 min once a day for 4 days. Fourteen horses (mean +/- s.d. age 9 +/- 3.2 years) were assigned randomly to Group A (sedated) and Group B (nonsedated). Group A were given 20-30 microg/kg bwt romifidine within 10-15 min prior to the start of the first acclimating run. Acclimation was determined by the time taken to reach a threshold heart rate value.

RESULTS

Group A and B reached threshold heart rate values by the 6th minute of the 4th run (72.8 beats/min) and the 6th min of the 3rd run (78.7 beats/min), respectively. No significant difference was found (P>0.05) between Group A and B in the time taken to reach threshold heart rate values. Acclimation to water treadmill exercise requires a minimum of 2 x 15 min nonsedated acclimating runs. Sedation can be used to prevent horses panicking during the first exposure but thereafter does not affect the time taken to acclimate.

POTENTIAL RELEVANCE

Previous experience of water treadmill exercise should be taken into consideration prior to collecting physiological and biomechanical data. Further studies detailing the physiological and biomechanical responses are required prior to making recommendations for the incorporation of this mode of exercise into rehabilitation programmes.

Use of a chaperone during breast examination: the attitude and practice of consultant breast surgeons in the United Kingdom

BACKGROUND

Professional guidelines and clinical practice regarding use of chaperones vary substantially in different health care settings. Although there are several studies in primary care practice, no such studies are available in a breast care setting. We have undertaken a questionnaire survey of practicing consultant breast surgeons in the U.K. regarding the use of a chaperone during breast examination.

METHOD

A self-completion questionnaire, with 18 items was developed, piloted, modified and mailed to 400 consultant breast surgeons across the U.K.

RESULT

302/400 questionnaires were returned (76%). Sixty-five per cent had a policy on the use of chaperone. Although 73% always offer a chaperone, the majority never documented the offer (74%) or identity (73%). Overall use of chaperone was significantly higher among male (82%), compared to female surgeons (38%, p < 0.001). The majority said that patient embarrassment (54%) and the availability of a nurse (57%) strongly influence chaperone use unlike patient's age, marital status, ethnicity, anxiety, instinct. Seventy per cent of respondents believed that the presence of a chaperone was important for medico-legal protection of doctor and patient (55%).

CONCLUSION

Our study shows that the majority of consultant breast surgeons in the UK use a chaperone. The overall use of a chaperone in secondary breast care setting is higher compared to previous studies in primary care. Documentation of the offer and identity of the chaperone is very poor.

Prosthetic ankle-foot mechanism capable of automatic adaptation to the walking surface

A conceptual design has been generated for a prosthetic ankle-foot mechanism that can automatically adapt to the slope of the walking surface. To help prove this concept, a prototype ankle-foot mechanism was designed, developed, and tested on three subjects with unilateral transtibial amputations walking on level and ramped surfaces. The mechanism is capable of automatically adapting to the walking surface by switching impedance modes at key points of the gait cycle. The mechanism simulates the behavior of the physiologic foot and ankle complex by having a low impedance in the early stance phase and then switching to a higher impedance once foot-flat is reached. The "set-point" at which these changes in impedance occur gets reset on every step in order to reach the proper alignment for the walking surface. The mechanism utilizes the user's bodyweight to help switch impedance modes and does not require any active control. It was hypothesized that the ankle-foot mechanism would cause the equilibrium point of the ankle moment versus the ankle dorsiflexion angle curves to shift to accommodate the walking surface. For two of the three subjects tested, this behavior was confirmed, supporting the contention that the design provides automatic adaptation for different walking slopes. Further work is needed to develop the prototype into a commercial product, but the mechanism was sufficient for illustrating proof-of-concept.

Patients' attitude towards the use of a chaperone in breast examination

INTRODUCTION

The aim of this study was to assess the attitude and the preferences of patients towards the use of a chaperone during breast examination.

PATIENTS AND METHODS

A two-part questionnaire was circulated among 204 consecutive new patients, attending both symptomatic breast and screened assessment clinics.

RESULTS

A total of 200 questionnaires were fully completed and returned. Although 104 (52%) patients felt that they did not need a chaperone during breast examination, 65 (33%) preferred to have one. Amongst these 65 patients, the majority (52%) wanted a chaperone in the presence of both a male and female doctor whereas 19 (29%) wanted a chaperone in the presence of a male doctor. When patients were asked which person would be the best chaperone for them, 63 patients (32%) preferred their spouse to act as a chaperone, whereas 57 (29%) preferred a clinic nurse. However, the majority of teenagers and young adults (10-30 years) preferred their parents to act as a chaperone. On asking the reason for preferring a chaperone during breast examination, 69% felt a chaperone helped them to feel more at ease, 28% felt they get more support, 23% get less embarrassed and 10% felt safer. The majority (54%) preferred the nurse to offer a chaperone instead of the doctor (22%). Patients generally said they were comfortable in asking for a chaperone (68%). Overall, 68% of patients considered the offer of a chaperone as a sign of respect and the majority felt the attitude (32%) and gender (20%) of the clinician are the two most important factors influencing the chaperone use. Most patients were of the opinion that the presence of a chaperone does not have a negative effect on the doctor-patient relationship (75%), patient confidentiality (74%) and do not cause embarrassment (68%). Following their assessment in clinic, the patients' views on the use of a chaperone were not significantly changed.

CONCLUSIONS

There is a wide variety of opinion among patients about the desirability of a chaperone during breast examination. However, the majority consider the offer of a chaperone as a sign of respect and many patients commented that the presence of a chaperone is important for medicolegal protection of both patient and clinician. In recent years, there has been an increasing call from medicolegal societies and medical insurance companies for greater use of chaperones during intimate examinations. We feel that recommendations regarding the use of a chaperone should now be incorporated into the British Association of Surgical Oncology guidelines.

Physical and chemical properties of lysozyme

The conformations of lysozyme in crystals and in aqueous solution are discussed and it is shown that the basic conformation is similar in the two states. Certain parts of the molecule have mobility. The reactions of lysozyme with protons, metal ions and some organic reagents are examined in the light of the conformations and their dynamics. The reactions considered are mainly those of tyrosyl, tryptophyl and carboxylate residues. The reactivity data are used in a discussion of the energy states of the reacting side-chains. In particular the reactivity of Glu-35 and its interaction with Trp-108 lead to suggestions for some new aspects in the hypothesis for the mechanism of action of lysozyme. In most respects the X-ray crystal diffraction and the nuclear magnetic resonance solution studies are in accord and complementary.

Elemental analysis of neurofibrillary tangles in Alzheimer's disease using proton-induced X-ray analysis

We have investigated the elemental content of hippocampal slices from normal human brain and from brains of Alzheimer's disease patients by X-ray fluorescence using both electron and proton beam microprobes. The sections have been stained with a dye--toluidine blue--which contains sulphur so that the X-ray fluorescence map can be correlated with known intracellular sites as seen under the light microscope. The results show that associated with neurofibrillary tangles and Hirano bodies (the distinctive internal visual features of cells from Alzheimer's disease patients) there is increased calcium. We cannot confirm that there are peculiarities in the distribution of aluminium in cells.

Introduction to silicon chemistry and biochemistry

An outline of the chemistry of silicon is given, stressing the reactions in water. In biological systems the metabolism of silicon is little known but much silica is deposited in a variety of amorphous forms. The differences between this biological silica and mineral silicas and silicates, which can be health hazards, are indicated. However both manufactured mineral phase and molecules containing silica can be valuable in medicine.

The physics and chemistry of the calcium-binding proteins

The structures of several calcium-binding proteins are known in considerable detail in both crystalline and solution states. The changes of structure with the binding of calcium, protons, magnesium and hydrophobic molecules are also known. It appears that some calcium-binding structures contain relays of cooperative interaction which run via helices between different parts of these proteins, for example in calmodulin. In others the effect of binding, of for instance calcium, is minimal, as in phospholipase A2. In another group the effect of binding of ions leads to cooperative further binding so that ternary or higher-order complexes are formed, as in the activation of prothrombin. The linking of cellular activities to calcium is thus dependent on several highly developed properties of particular proteins in special environments which have been selected to take advantage of the peculiarities of the calcium ion, namely its particular coordination chemistry and its speed of reaction. The link between calcium, its proteins and activity is not directly to catalysis but is primarily to mechanical properties.