Opposing brain signatures of sleep in task-based and resting-state conditions

Sleep and depression have a complex, bidirectional relationship, with sleep-associated alterations in brain dynamics and structure impacting a range of symptoms and cognitive abilities. Previous work describing these relationships has provided an incomplete picture by investigating only one or two types of sleep measures, depression, or neuroimaging modalities in parallel. We analyze the correlations between brainwide neural signatures of sleep, cognition, and depression in task and resting-state data from over 30,000 individuals from the UK Biobank and Human Connectome Project. Neural signatures of insomnia and depression are negatively correlated with those of sleep duration measured by accelerometer in the task condition but positively correlated in the resting-state condition. Our results show that resting-state neural signatures of insomnia and depression resemble that of rested wakefulness. This is further supported by our finding of hypoconnectivity in task but hyperconnectivity in resting-state data in association with insomnia and depression. These observations dispute conventional assumptions about the neurofunctional manifestations of hyper- and hypo-somnia, and may explain inconsistent findings in the literature.

Essential requirements for the governance and management of data trusts, data repositories, and other data collaborations

Introduction

Around the world, many organisations are working on ways to increase the use, sharing, and reuse of person-level data for research, evaluation, planning, and innovation while ensuring that data are secure and privacy is protected. As a contribution to broader efforts to improve data governance and management, in 2020 members of our team published 12 minimum specification essential requirements (min specs) to provide practical guidance for organisations establishing or operating data trusts and other forms of data infrastructure.

Approach and Aims

We convened an international team, consisting mostly of participants from Canada and the United States of America, to test and refine the original 12 min specs. Twenty-three (23) data-focused organisations and initiatives recorded the various ways they address the min specs. Sub-teams analysed the results, used the findings to make improvements to the min specs, and identified materials to support organisations/initiatives in addressing the min specs.

Results

Analyses and discussion led to an updated set of 15 min specs covering five categories: one min spec for Legal, five for Governance, four for Management, two for Data Users, and three for Stakeholder & Public Engagement. Multiple changes were made to make the min specs language more technically complete and precise. The updated set of 15 min specs has been integrated into a Canadian national standard that, to our knowledge, is the first to include requirements for public engagement and Indigenous Data Sovereignty.

Conclusions

The testing and refinement of the min specs led to significant additions and improvements. The min specs helped the 23 organisations/initiatives involved in this project communicate and compare how they achieve responsible and trustworthy data governance and management. By extension, the min specs, and the Canadian national standard based on them, are likely to be useful for other data-focused organisations and initiatives.

Out with AI, in with the psychiatrist: a preference for human-derived clinical decision support in depression care

Advancements in artificial intelligence (AI) are enabling the development of clinical support tools (CSTs) in psychiatry to facilitate the review of patient data and inform clinical care. To promote their successful integration and prevent over-reliance, it is important to understand how psychiatrists will respond to information provided by AI-based CSTs, particularly if it is incorrect. We conducted an experiment to examine psychiatrists' perceptions of AI-based CSTs for treating major depressive disorder (MDD) and to determine whether perceptions interacted with the quality of CST information. Eighty-three psychiatrists read clinical notes about a hypothetical patient with MDD and reviewed two CSTs embedded within a single dashboard: the note's summary and a treatment recommendation. Psychiatrists were randomised to believe the source of CSTs was either AI or another psychiatrist, and across four notes, CSTs provided either correct or incorrect information. Psychiatrists rated the CSTs on various attributes. Ratings for note summaries were less favourable when psychiatrists believed the notes were generated with AI as compared to another psychiatrist, regardless of whether the notes provided correct or incorrect information. A smaller preference for psychiatrist-generated information emerged in ratings of attributes that reflected the summary's accuracy or its inclusion of important information from the full clinical note. Ratings for treatment recommendations were also less favourable when their perceived source was AI, but only when recommendations were correct. There was little evidence that clinical expertise or familiarity with AI impacted results. These findings suggest that psychiatrists prefer human-derived CSTs. This preference was less pronounced for ratings that may have prompted a deeper review of CST information (i.e. a comparison with the full clinical note to evaluate the summary's accuracy or completeness, assessing an incorrect treatment recommendation), suggesting a role of heuristics. Future work should explore other contributing factors and downstream implications for integrating AI into psychiatric care.

Predictive care: a protocol for a computational ethnographic approach to building fair models of inpatient violence in emergency psychiatry

INTRODUCTION

Managing violence or aggression is an ongoing challenge in emergency psychiatry. Many patients identified as being at risk do not go on to become violent or aggressive. Efforts to automate the assessment of risk involve training machine learning (ML) models on data from electronic health records (EHRs) to predict these behaviours. However, no studies to date have examined which patient groups may be over-represented in false positive predictions, despite evidence of social and clinical biases that may lead to higher perceptions of risk in patients defined by intersecting features (eg, race, gender). Because risk assessment can impact psychiatric care (eg, via coercive measures, such as restraints), it is unclear which patients might be underserved or harmed by the application of ML.

METHODS AND ANALYSIS

We pilot a computational ethnography to study how the integration of ML into risk assessment might impact acute psychiatric care, with a focus on how EHR data is compiled and used to predict a risk of violence or aggression. Our objectives include: (1) evaluating an ML model trained on psychiatric EHRs to predict violent or aggressive incidents for intersectional bias; and (2) completing participant observation and qualitative interviews in an emergency psychiatric setting to explore how social, clinical and structural biases are encoded in the training data. Our overall aim is to study the impact of ML applications in acute psychiatry on marginalised and underserved patient groups.

ETHICS AND DISSEMINATION

The project was approved by the research ethics board at The Centre for Addiction and Mental Health (053/2021). Study findings will be presented in peer-reviewed journals, conferences and shared with service users and providers.

Symptom dimensions of major depression in a large community-based cohort

BACKGROUND

Our understanding of major depression is complicated by substantial heterogeneity in disease presentation, which can be disentangled by data-driven analyses of depressive symptom dimensions. We aimed to determine the clinical portrait of such symptom dimensions among individuals in the community.

METHODS

This cross-sectional study consisted of 25 261 self-reported White UK Biobank participants with major depression. Nine questions from the UK Biobank Mental Health Questionnaire encompassing depressive symptoms were decomposed into underlying factors or 'symptom dimensions' via factor analysis, which were then tested for association with psychiatric diagnoses and polygenic risk scores for major depressive disorder (MDD), bipolar disorder and schizophrenia. Replication was performed among 655 self-reported non-White participants, across sexes, and among 7190 individuals with an ICD-10 code for MDD from linked inpatient or primary care records.

RESULTS

Four broad symptom dimensions were identified, encompassing negative cognition, functional impairment, insomnia and atypical symptoms. These dimensions replicated across ancestries, sexes and individuals with inpatient or primary care MDD diagnoses, and were also consistent among 43 090 self-reported White participants with undiagnosed self-reported depression. Every dimension was associated with increased risk of nearly every psychiatric diagnosis and polygenic risk score. However, while certain psychiatric diagnoses were disproportionately associated with specific symptom dimensions, the three polygenic risk scores did not show the same specificity of associations.

CONCLUSIONS

An analysis of questionnaire data from a large community-based cohort reveals four replicable symptom dimensions of depression with distinct clinical, but not genetic, correlates.

Clinical features associated with ADB-BUTINACA exposure in patients attending emergency departments in England

OBJECTIVE

Synthetic cannabinoid receptor agonists (SCRA) are commonly encountered new psychoactive substances. Here we report the recent detection of ADB-BUTINACA in samples from patients attending United Kingdom emergency departments with toxicity after suspected drug misuse and describe the associated clinical features.

METHODS

Consenting adults (≥16 y) presenting to participating hospitals with toxicity after suspected drug misuse have been included in the Identification Of Novel psychoActive substances (IONA) study since March 2015. Demographic and clinical features are recorded and blood and/or urine samples analysed using high-resolution accurate mass liquid chromatography-mass spectrometry.

RESULTS

By December 2021, analytical data were available for 1279 IONA participants and ADB-BUTINACA was detected in at least one sample from 10 (9 males, age range 16-51 median 45 years), all presenting since February 2021. Smoking 'spice' was reported by four patients, two had ingested edible "cannabis" gums and four reported heroin use (2 intravenous, 1 smoked, 1 route not known). Co-use of pregabalin (oral) and crack cocaine (smoked) were also reported. In 3 cases ADB-BUTINACA was the only substance detected, while in seven other substances of misuse were also detected including other SCRA, opioids, benzodiazepines cocaine and pregabalin. Clinical features reported in these 2 groups respectively included reduced level of consciousness (3/3, 6/7), agitation (0/3, 4/7), tachycardia (0/3, 3/7), seizures (1/3, 1/7), hallucinations (1/3, 1/7), hypotension (1/3, 1/7). Metabolic acidosis (1/3, 0/7) and respiratory acidosis (1/3, 0/7), All 10 patients recovered with supportive care, including intubation and ventilation for one case. The median length of hospital stay was 19 h (range 2.6-131 h).

CONCLUSIONS

ADB-BUTINACA has recently emerged as a drug of misuse in England. Clinical features of toxicity are consistent with those of other SCRA and include reduced level of consciousness, respiratory and/or metabolic acidosis, seizures, confusion and hallucinations.

International data governance for neuroscience

As neuroscience projects increase in scale and cross international borders, different ethical principles, national and international laws, regulations, and policies for data sharing must be considered. These concerns are part of what is collectively called data governance. Whereas neuroscience data transcend borders, data governance is typically constrained within geopolitical boundaries. An international data governance framework and accompanying infrastructure can assist investigators, institutions, data repositories, and funders with navigating disparate policies. Here, we propose principles and operational considerations for how data governance in neuroscience can be navigated at an international scale and highlight gaps, challenges, and opportunities in a global brain data ecosystem. We consider how to approach data governance in a way that balances data protection requirements and the need for open science, so as to promote international collaboration through federated constructs such as the International Brain Initiative (IBI).

Conceptualising fairness: three pillars for medical algorithms and health equity

OBJECTIVES

Fairness is a core concept meant to grapple with different forms of discrimination and bias that emerge with advances in Artificial Intelligence (eg, machine learning, ML). Yet, claims to fairness in ML discourses are often vague and contradictory. The response to these issues within the scientific community has been technocratic. Studies either measure (mathematically) competing definitions of fairness, and/or recommend a range of governance tools (eg, fairness checklists or guiding principles). To advance efforts to operationalise fairness in medicine, we synthesised a broad range of literature.

METHODS

We conducted an environmental scan of English language literature on fairness from 1960-July 31, 2021. Electronic databases Medline, PubMed and Google Scholar were searched, supplemented by additional hand searches. Data from 213 selected publications were analysed using rapid framework analysis. Search and analysis were completed in two rounds: to explore previously identified issues (a priori), as well as those emerging from the analysis (de novo).

RESULTS

Our synthesis identified 'Three Pillars for Fairness': transparency, impartiality and inclusion. We draw on these insights to propose a multidimensional conceptual framework to guide empirical research on the operationalisation of fairness in healthcare.

DISCUSSION

We apply the conceptual framework generated by our synthesis to risk assessment in psychiatry as a case study. We argue that any claim to fairness must reflect critical assessment and ongoing social and political deliberation around these three pillars with a range of stakeholders, including patients.

CONCLUSION

We conclude by outlining areas for further research that would bolster ongoing commitments to fairness and health equity in healthcare.

The Neuron Phenotype Ontology: A FAIR Approach to Proposing and Classifying Neuronal Types

The challenge of defining and cataloging the building blocks of the brain requires a standardized approach to naming neurons and organizing knowledge about their properties. The US Brain Initiative Cell Census Network, Human Cell Atlas, Blue Brain Project, and others are generating vast amounts of data and characterizing large numbers of neurons throughout the nervous system. The neuroscientific literature contains many neuron names (e.g. parvalbumin-positive interneuron or layer 5 pyramidal cell) that are commonly used and generally accepted. However, it is often unclear how such common usage types relate to many evidence-based types that are proposed based on the results of new techniques. Further, comparing different types across labs remains a significant challenge. Here, we propose an interoperable knowledge representation, the Neuron Phenotype Ontology (NPO), that provides a standardized and automatable approach for naming cell types and normalizing their constituent phenotypes using identifiers from community ontologies as a common language. The NPO provides a framework for systematically organizing knowledge about cellular properties and enables interoperability with existing neuron naming schemes. We evaluate the NPO by populating a knowledge base with three independent cortical neuron classifications derived from published data sets that describe neurons according to molecular, morphological, electrophysiological, and synaptic properties. Competency queries to this knowledge base demonstrate that the NPO knowledge model enables interoperability between the three test cases and neuron names commonly used in the literature.

Association of accelerometer-derived sleep measures with lifetime psychiatric diagnoses: A cross-sectional study of 89,205 participants from the UK Biobank

BACKGROUND

Sleep problems are both symptoms of and modifiable risk factors for many psychiatric disorders. Wrist-worn accelerometers enable objective measurement of sleep at scale. Here, we aimed to examine the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a large community-based cohort.

METHODS AND FINDINGS

In this post hoc cross-sectional analysis of the UK Biobank cohort, 10 interpretable sleep measures-bedtime, wake-up time, sleep duration, wake after sleep onset, sleep efficiency, number of awakenings, duration of longest sleep bout, number of naps, and variability in bedtime and sleep duration-were derived from 7-day accelerometry recordings across 89,205 participants (aged 43 to 79, 56% female, 97% self-reported white) taken between 2013 and 2015. These measures were examined for association with lifetime inpatient diagnoses of major depressive disorder, anxiety disorders, bipolar disorder/mania, and schizophrenia spectrum disorders from any time before the date of accelerometry, as well as polygenic risk scores for major depression, bipolar disorder, and schizophrenia. Covariates consisted of age and season at the time of the accelerometry recording, sex, Townsend deprivation index (an indicator of socioeconomic status), and the top 10 genotype principal components. We found that sleep pattern differences were ubiquitous across diagnoses: each diagnosis was associated with a median of 8.5 of the 10 accelerometer-derived sleep measures, with measures of sleep quality (for instance, sleep efficiency) generally more affected than mere sleep duration. Effect sizes were generally small: for instance, the largest magnitude effect size across the 4 diagnoses was β = -0.11 (95% confidence interval -0.13 to -0.10, p = 3 × 10-56, FDR = 6 × 10-55) for the association between lifetime inpatient major depressive disorder diagnosis and sleep efficiency. Associations largely replicated across ancestries and sexes, and accelerometry-derived measures were concordant with self-reported sleep properties. Limitations include the use of accelerometer-based sleep measurement and the time lag between psychiatric diagnoses and accelerometry.

CONCLUSIONS

In this study, we observed that sleep pattern differences are a transdiagnostic feature of individuals with lifetime mental illness, suggesting that they should be considered regardless of diagnosis. Accelerometry provides a scalable way to objectively measure sleep properties in psychiatric clinical research and practice, even across tens of thousands of individuals.

Rodent somatosensory thalamocortical circuitry: Neurons, synapses, and connectivity

As our understanding of the thalamocortical system deepens, the questions we face become more complex. Their investigation requires the adoption of novel experimental approaches complemented with increasingly sophisticated computational modeling. In this review, we take stock of current data and knowledge about the circuitry of the somatosensory thalamocortical loop in rodents, discussing common principles across modalities and species whenever appropriate. We review the different levels of organization, including the cells, synapses, neuroanatomy, and network connectivity. We provide a complete overview of this system that should be accessible for newcomers to this field while nevertheless being comprehensive enough to serve as a reference for seasoned neuroscientists and computational modelers studying the thalamocortical system. We further highlight key gaps in data and knowledge that constitute pressing targets for future experimental work. Filling these gaps would provide invaluable information for systematically unveiling how this system supports behavioral and cognitive processes.

Effect of the UK Psychoactive Substances Act 2016 on episodes of toxicity related to new psychoactive substances as reported to the National Poisons Information Service. A time series analysis

BACKGROUND

There have been recent increases in use of new psychoactive substances (NPS) associated with acute health harms including hospital presentations due to toxicity and increasing numbers of deaths. In response, the UK Government enacted generic legislation on 26th May 2016 (the Psychoactive Substances Act) making it an offence to produce, possess with intent to supply, supply, import or export, or possess within a custodial setting a psychoactive substance. We studied the impact of this Act on monthly frequency of enquiries made by health professionals to the UK National Poisons Information Service (NPIS) about NPS. We also studied five commonly used 'conventional' drugs of misuse that had been controlled prior to January 2009.

METHOD

Anonymised clinical enquiries to the NPIS and accesses to the poisons information database TOXBASE were reviewed retrospectively from January 2009 to December 2018 to ascertain the trends in reported toxicity for NPS, cocaine, heroin, cannabis, amphetamines and MDMA. Data were analysed using interrupted time series analysis with the date of the PSA used as an independent predictor.

RESULTS

Over the period of study there were 3,866 NPIS telephone enquiries and 79,271 TOXBASE user accesses made by UK health professionals concerning NPS. There were increases in monthly TOXBASE accesses (t = 7.408, P < 0.0001) and telephone enquiries (t = 4.74, P < 0.001) over the pre-specified period January 2009 to May 2016. Comparing the period after the PSA with that before, there were significant reductions in TOXBASE accesses (t = -3.327, P < 0.001) and telephone enquiries (t = -6.97, P < 0.001), although reductions started before May 2016. There were no significant changes for the five conventional drugs. There were significant reductions in telephone enquiries (t = -3.418, P < 0.001) and non-significant reductions in TOXBASE accesses (t = -1.713, P = 0.089) for NPS between June 2016 and December 2018. Increases in telephone enquiries for cocaine and reductions TOXBASE accesses for MDMA were also observed over that period.

CONCLUSIONS

There have been significant recent reductions in NPIS enquiry activity relating to NPS; although these began before enactment of the PSA in May 2016.

Antarctic Futures: An Assessment of Climate-Driven Changes in Ecosystem Structure, Function, and Service Provisioning in the Southern Ocean

In this article, we analyze the impacts of climate change on Antarctic marine ecosystems. Observations demonstrate large-scale changes in the physical variables and circulation of the Southern Ocean driven by warming, stratospheric ozone depletion, and a positive Southern Annular Mode. Alterations in the physical environment are driving change through all levels of Antarctic marine food webs, which differ regionally. The distributions of key species, such as Antarctic krill, are also changing. Differential responses among predators reflect differences in species ecology. The impacts of climate change on Antarctic biodiversity will likely vary for different communities and depend on species range. Coastal communities and those of sub-Antarctic islands, especially range-restricted endemic communities, will likely suffer the greatest negative consequences of climate change. Simultaneously, ecosystem services in the Southern Ocean will likely increase. Such decoupling of ecosystem services and endemic species will require consideration in the management of human activities such as fishing in Antarctic marine ecosystems.

The importance of Antarctic krill in biogeochemical cycles

Antarctic krill (Euphausia superba) are swarming, oceanic crustaceans, up to two inches long, and best known as prey for whales and penguins - but they have another important role. With their large size, high biomass and daily vertical migrations they transport and transform essential nutrients, stimulate primary productivity and influence the carbon sink. Antarctic krill are also fished by the Southern Ocean's largest fishery. Yet how krill fishing impacts nutrient fertilisation and the carbon sink in the Southern Ocean is poorly understood. Our synthesis shows fishery management should consider the influential biogeochemical role of both adult and larval Antarctic krill.

Krill faecal pellets drive hidden pulses of particulate organic carbon in the marginal ice zone

The biological carbon pump drives a flux of particulate organic carbon (POC) through the ocean and affects atmospheric levels of carbon dioxide. Short term, episodic flux events are hard to capture with current observational techniques and may thus be underrepresented in POC flux estimates. We model the potential hidden flux of POC originating from Antarctic krill, whose swarming behaviour could result in a major conduit of carbon to depth through their rapid exploitation of phytoplankton blooms and bulk egestion of rapidly sinking faecal pellets (FPs). Our model results suggest a seasonal krill FP export flux of 0.039 GT C across the Southern Ocean marginal ice zone, corresponding to 17-61% (mean 35%) of current satellite-derived export estimates for this zone. The magnitude of our conservatively estimated flux highlights the important role of large, swarming macrozooplankton in POC export and, the need to incorporate such processes more mechanistically to improve model projections.

Serum and plasma metabolites associated with postpartum ovulation and pregnancy risks in suckled beef cows subjected to artificial insemination

Two experiments were conducted to determine relationships of blood metabolite concentrations, BW, BCS, and rump fat depth with postpartum ovulation and pregnancy risks, as well as their utility in predicting those outcomes in suckled beef cows. In experiment 1, plasma glucose collected 10 and 3 d before AI of suckled beef cows at seven locations did not differ between cows that had resumed estrous cycles (ovulated) before AI compared with anovulatory cows, whereas plasma glucose 3 d before AI was greater (P < 0.01) in cows that became pregnant compared with nonpregnant cows. Serum beta-hydroxybutyrate (BHB) tended (P = 0.09) to be less in ovulatory cows compared with anovulatory cows 10 d before AI, but was unrelated to pregnancy status. Receiver-operator derived true-positive (sensitivity) and false-positive (1-specificity) risks were determined for plasma glucose and serum BHB as predictors for postpartum ovulation and pregnancy status. Serum BHB 3 d before AI produced true-positive and false-positive risks of 82% and 37%, respectively, when predicting ovulatory status before AI. Serum BHB 10 d before AI produced a true-positive and false-positive risks of 92% and 25%, respectively, when predicting pregnancy status. In experiment 2, blood was collected weekly for 12 wk from multiparous suckled beef cows to assess blood metabolite concentrations in addition to concurrent weekly assessments of BW, BCS, and rump fat. When blood metabolites and physical measures were normalized to parturition reflecting changes occurring during the first 6 wk after calving, we observed reduced (P < 0.05) concentrations of serum BHB and NEFA, and greater (P < 0.05) rump fat and BCS in cows that ovulated before first AI, whereas reduced (P < 0.05) plasma glucose was characteristic of cows that became pregnant. When blood metabolites and physical measures were normalized to the onset of the AI program reflecting changes during 6 wk before AI, ovulatory cows had increased (P < 0.05) BCS and lower (P < 0.05) NEFA from 3 to 6 wk before the onset of the AI program compared with anovulatory cows. With all predictor variables in regression models, some multiple correlation coefficients (R2) exceeded 50% when predicting postpartum ovulatory status, but those for predicting pregnancy risk were less than 25%. Although measures of BCS and BHB during 6 wk after calving were related to postpartum ovulation risk, rump fat, glucose, BCS, and NEFA were associated with cows that were ovulatory and pregnant.

Two split-time artificial insemination programs in suckled beef cows

Our objective was to determine which of 2 split-time AI programs applied to suckled beef cows would result in greater pregnancy risk. Suckled beef cows (n = 1,062) at 12 locations in 4 states (CO, KS, MY, and WA) were enrolled. Cows were treated on d -7 with a progesterone insert concurrent with 100 µg GnRH and on d 0 with 25 mg PGF plus removal of the insert. Estrus-detection patches were affixed to cows at insert removal. The study was designed as a completely randomized experiment of 2 treatment combinations. Within location and balanced for parity (primiparous vs. multiparous), cows were assigned randomly to 2 treatment times (55 vs. 65 h after CIDR insert removal) at which time estrus-detection patches were assessed. Estrus was defined to have occurred when an estrus-detection patch was > 50% colored (activated). Cows determined to be in estrus were inseminated at either 55 or 65 h, whereas the residual nonestrous cows in both treatment times received GnRH at 55 or 65 h but were inseminated 20 h later at 75 or 85 h, respectively. Pregnancy outcomes were determined at 36 d after AI and at the end of the breeding season. Thus, pregnancy outcomes of interest were compared between the 55 + 75-h treatment combination and that of the 65+85-h combination. Expression of estrus was greater ( = 0.001) by 65 h after PGF than by 55 h (62.0% vs. 41.9%), respectively, and this proportion was influenced by parity (time x parity interaction; = 0.006). As a result, proportionally more ( < 0.001) cows received the timed AI at 75 than 85 h (59.4% vs. 40.6%). Similar proportions of cows not in estrus by 55 or 65 h were detected in estrus by 75 or 85 h (40.1% vs. 39.3%), respectively. The cumulative proportion of cows in estrus by 75 h was less ( < 0.001) than that by 85 h (66.7% vs. 76.7%), respectively. Pregnancy risks at 36 d differed among treatments, with cows detected in estrus and inseminated at 55 or 65 h having greater pregnancy risks than their time-inseminated herd mates at 75 or 85 h (62.3% vs.49.7%), respectively. Overall pregnancy risk for cows in the 65+85-h treatment combination was greater at 36 d than for cows in the 55 + 75-h treatment combination (61.0% vs. 51.4%), respectively. We conclude that the 65 + 85-h treatment combination produced more pregnancies than the 55 + 75-h combination, but its implementation may be somewhat less convenient in terms of cow handling times.

OSIRIS-REx Contamination Control Strategy and Implementation

OSIRIS-REx will return pristine samples of carbonaceous asteroid Bennu. This article describes how pristine was defined based on expectations of Bennu and on a realistic understanding of what is achievable with a constrained schedule and budget, and how that definition flowed to requirements and implementation. To return a pristine sample, the OSIRIS-REx spacecraft sampling hardware was maintained at level 100 A/2 and <180 ng/cm² of amino acids and hydrazine on the sampler head through precision cleaning, control of materials, and vigilance. Contamination is further characterized via witness material exposed to the spacecraft assembly and testing environment as well as in space. This characterization provided knowledge of the expected background and will be used in conjunction with archived spacecraft components for comparison with the samples when they are delivered to Earth for analysis. Most of all, the cleanliness of the OSIRIS-REx spacecraft was achieved through communication among scientists, engineers, managers, and technicians.

Using estrus detection patches to optimally time insemination improved pregnancy risk in suckled beef cows enrolled in a fixed-time artificial insemination program

A multilocation study examined pregnancy risk (PR) after delaying AI in suckled beef cows from 60 to 75 h when estrus had not been detected by 60 h in response to a 7-d CO-Synch + progesterone insert (CIDR) timed AI (TAI) program (d -7: CIDR insert concurrent with an injection of GnRH; d 0: PGF injection and removal of CIDR insert; and GnRH injection at TAI [60 or 75 h after CIDR removal]). A total of 1,611 suckled beef cows at 15 locations in 9 states (CO, IL, KS, MN, MS, MT, ND, SD, and VA) were enrolled. Before applying the fixed-time AI program, BCS was assessed, and blood samples were collected. Estrus was defined to have occurred when an estrus detection patch was >50% colored (activated). Pregnancy was determined 35 d after AI via transrectal ultrasound. Cows ( = 746) detected in estrus by 60 h (46.3%) after CIDR removal were inseminated and treated with GnRH at AI (Control). Remaining nonestrous cows were allocated within location to 3 treatments on the basis of parity and days postpartum: 1) GnRH injection and AI at 60 h (early-early = EE; = 292), 2) GnRH injection at 60 h and AI at 75 h (early-delayed = ED; = 282), or 3) GnRH injection and AI at 75 h (delayed-delayed = DD; = 291). Control cows had a greater ( < 0.01) PR (64.2%) than other treatments (EE = 41.7%, ED = 52.8%, DD = 50.0%). Use of estrus detection patches to delay AI in cows not in estrus by 60 h after CIDR insert removal (ED and DD treatments) increased ( < 0.05) PR to TAI when compared with cows in the EE treatment. More ( < 0.001) cows that showed estrus by 60 h conceived to AI at 60 h than those not showing estrus (64.2% vs. 48.1%). Approximately half (49.2%) of the cows not in estrus by 60 h had activated patches by 75 h, resulting in a greater ( < 0.05) PR than their nonestrous herd mates in the EE (46.1% vs. 34.5%), ED (64.2% vs. 39.2%), and DD (64.8% vs. 31.5%) treatments, respectively. Overall, cows showing estrus by 75 h (72.7%) had greater ( < 0.001) PR to AI (61.3% vs. 37.9%) than cows not showing estrus. Use of estrus detection patches to allow for a delayed AI in cows not in estrus by 60 h after removal of the CIDR insert improved PR to TAI by optimizing the timing of the AI in those cows.

A Framework for Collaborative Curation of Neuroscientific Literature

Large models of complex neuronal circuits require specifying numerous parameters, with values that often need to be extracted from the literature, a tedious and error-prone process. To help establishing shareable curated corpora of annotations, we have developed a literature curation framework comprising an annotation format, a Python API (NeuroAnnotation Toolbox; NAT), and a user-friendly graphical interface (NeuroCurator). This framework allows the systematic annotation of relevant statements and model parameters. The context of the annotated content is made explicit in a standard way by associating it with ontological terms (e.g., species, cell types, brain regions). The exact position of the annotated content within a document is specified by the starting character of the annotated text, or the number of the figure, the equation, or the table, depending on the context. Alternatively, the provenance of parameters can also be specified by bounding boxes. Parameter types are linked to curated experimental values so that they can be systematically integrated into models. We demonstrate the use of this approach by releasing a corpus describing different modeling parameters associated with thalamo-cortical circuitry. The proposed framework supports a rigorous management of large sets of parameters, solving common difficulties in their traceability. Further, it allows easier classification of literature information and more efficient and systematic integration of such information into models and analyses.

Data Publications Correlate with Citation Impact

Neuroscience and molecular biology have been generating large datasets over the past years that are reshaping how research is being conducted. In their wake, open data sharing has been singled out as a major challenge for the future of research. We conducted a comparative study of citations of data publications in both fields, showing that the average publication tagged with a data-related term by the NCBI MeSH (Medical Subject Headings) curators achieves a significantly larger citation impact than the average in either field. We introduce a new metric, the data article citation index (DAC-index), to identify the most prolific authors among those data-related publications. The study is fully reproducible from an executable Rmd (R Markdown) script together with all the citation datasets. We hope these results can encourage authors to more openly publish their data.

Automatic target validation based on neuroscientific literature mining for tractography

Target identification for tractography studies requires solid anatomical knowledge validated by an extensive literature review across species for each seed structure to be studied. Manual literature review to identify targets for a given seed region is tedious and potentially subjective. Therefore, complementary approaches would be useful. We propose to use text-mining models to automatically suggest potential targets from the neuroscientific literature, full-text articles and abstracts, so that they can be used for anatomical connection studies and more specifically for tractography. We applied text-mining models to three structures: two well-studied structures, since validated deep brain stimulation targets, the internal globus pallidus and the subthalamic nucleus and, the nucleus accumbens, an exploratory target for treating psychiatric disorders. We performed a systematic review of the literature to document the projections of the three selected structures and compared it with the targets proposed by text-mining models, both in rat and primate (including human). We ran probabilistic tractography on the nucleus accumbens and compared the output with the results of the text-mining models and literature review. Overall, text-mining the literature could find three times as many targets as two man-weeks of curation could. The overall efficiency of the text-mining against literature review in our study was 98% recall (at 36% precision), meaning that over all the targets for the three selected seeds, only one target has been missed by text-mining. We demonstrate that connectivity for a structure of interest can be extracted from a very large amount of publications and abstracts. We believe this tool will be useful in helping the neuroscience community to facilitate connectivity studies of particular brain regions. The text mining tools used for the study are part of the HBP Neuroinformatics Platform, publicly available at http://connectivity-brainer.rhcloud.com/.

Commissioning for COPD care: a new, recordable metric that supports the patient interest

BACKGROUND

Healthcare metrics have been used to drive improvement in outcome and delivery in UK hospital stroke and cardiac care. This model is attractive for chronic obstructive pulmonary disease (COPD) care because of disease frequency and the burden it places on primary, secondary and integrated care services.

METHODS

Using 'hospital episode statistics' (UK 'coding'), we examined hospital 'bed days/1000 population' in 150 UK Primary Care Trusts (PCTs) during 2006-07 and 2007-08. Data were adjusted for COPD prevalence. We looked at year-on-year consistency and factors which influenced variation.

RESULTS

There were 248 996 COPD admissions during 2006-08. 'Bed days/1000 PCT population' was consistent between years (r = 0.87; P < 0.001). There was a >2-fold difference in bed days between the best and worst performing PCTs which was primarily a consequence of variation in emergency admission rate (P < 0.001) and proportion of emergency admissions due to COPD (P < 0.001) and to only a lesser extent length of hospital stay (P < 0.001).

CONCLUSIONS

Bed days/1000 population appears a useful annual metric of COPD care quality. Good COPD care keeps patients active and out of hospital and requires co-ordinated action from both hospital and community services, with an important role for integrated care. This metric demonstrates that current care is highly variable and offers a measurable target to commission against.

Interoperable atlases of the human brain

The last two decades have seen an unprecedented development of human brain mapping approaches at various spatial and temporal scales. Together, these have provided a large fundus of information on many different aspects of the human brain including micro- and macrostructural segregation, regional specialization of function, connectivity, and temporal dynamics. Atlases are central in order to integrate such diverse information in a topographically meaningful way. It is noteworthy, that the brain mapping field has been developed along several major lines such as structure vs. function, postmortem vs. in vivo, individual features of the brain vs. population-based aspects, or slow vs. fast dynamics. In order to understand human brain organization, however, it seems inevitable that these different lines are integrated and combined into a multimodal human brain model. To this aim, we held a workshop to determine the constraints of a multi-modal human brain model that are needed to enable (i) an integration of different spatial and temporal scales and data modalities into a common reference system, and (ii) efficient data exchange and analysis. As detailed in this report, to arrive at fully interoperable atlases of the human brain will still require much work at the frontiers of data acquisition, analysis, and representation. Among them, the latter may provide the most challenging task, in particular when it comes to representing features of vastly different scales of space, time and abstraction. The potential benefits of such endeavor, however, clearly outweigh the problems, as only such kind of multi-modal human brain atlas may provide a starting point from which the complex relationships between structure, function, and connectivity may be explored.

A biophysically detailed model of neocortical local field potentials predicts the critical role of active membrane currents

Brain activity generates extracellular voltage fluctuations recorded as local field potentials (LFPs). It is known that the relevant microvariables, the ionic currents across membranes, jointly generate the macrovariables, the extracellular voltage, but neither the detailed biophysical knowledge nor the required computational power have been available to model these processes. We simulated the LFP in a model of the rodent neocortical column composed of >12,000 reconstructed, multicompartmental, and spiking cortical layer 4 and 5 pyramidal neurons and basket cells, including five million dendritic and somatic compartments with voltage- and ion-dependent currents, realistic connectivity, and probabilistic AMPA, NMDA, and GABA synapses. We found that, depending on a number of factors, the LFP reflects local and cross-layer processing. Active currents dominate the generation of LFPs, not synaptic ones. Spike-related currents impact the LFP not only at higher frequencies but below 50 Hz. This work calls for re-evaluating the genesis of LFPs.

Decision-making for ecosystem-based management: evaluating options for a krill fishery with an ecosystem dynamics model

Decision-makers charged with implementing ecosystem-based management (EBM) rely on scientists to predict the consequences of decisions relating to multiple, potentially conflicting, objectives. Such predictions are inherently uncertain, and this can be a barrier to decision-making. The Convention on the Conservation of Antarctic Marine Living Resources requires managers of Southern Ocean fisheries to sustain the productivity of target stocks, the health and resilience of the ecosystem, and the performance of the fisheries themselves. The managers of the Antarctic krill fishery in the Scotia Sea and southern Drake Passage have requested advice on candidate management measures consisting of a regional catch limit and options for subdividing this among smaller areas. We developed a spatially resolved model that simulates krill-predator-fishery interactions and reproduces a plausible representation of past dynamics. We worked with experts and stakeholders to identify (1) key uncertainties affecting our ability to predict ecosystem state; (2) illustrative reference points that represent the management objectives; and (3) a clear and simple way of conveying our results to decision-makers. We developed four scenarios that bracket the key uncertainties and evaluated candidate management measures in each of these scenarios using multiple stochastic simulations. The model emphasizes uncertainty and simulates multiple ecosystem components relating to diverse objectives. We summarize the potentially complex results as estimates of the risk that each illustrative objective will not be achieved (i.e., of the state being outside the range specified by the reference point). This approach allows direct comparisons between objectives. It also demonstrates that a candid appraisal of uncertainty, in the form of risk estimates, can be an aid, rather than a barrier, to understanding and using ecosystem model predictions. Management measures that reduce coastal fishing, relative to oceanic fishing, apparently reduce risks to both the fishery and the ecosystem. However, alternative reference points could alter the perceived risks, so further stakeholder involvement is needed to identify risk metrics that appropriately represent their objectives.

Combinatorial expression rules of ion channel genes in juvenile rat (Rattus norvegicus) neocortical neurons

The electrical diversity of neurons arises from the expression of different combinations of ion channels. The gene expression rules governing these combinations are not known. We examined the expression of twenty-six ion channel genes in a broad range of single neocortical neuron cell types. Using expression data from a subset of twenty-six ion channel genes in ten different neocortical neuronal types, classified according to their electrophysiological properties, morphologies and anatomical positions, we first developed an incremental Support Vector Machine (iSVM) model that prioritizes the predictive value of single and combinations of genes for the rest of the expression pattern. With this approach we could predict the expression patterns for the ten neuronal types with an average 10-fold cross validation accuracy of 87% and for a further fourteen neuronal types not used in building the model, with an average accuracy of 75%. The expression of the genes for HCN4, Kv2.2, Kv3.2 and Caβ3 were found to be particularly strong predictors of ion channel gene combinations, while expression of the Kv1.4 and Kv3.3 genes has no predictive value. Using a logic gate analysis, we then extracted a spectrum of observed combinatorial gene expression rules of twenty ion channels in different neocortical neurons. We also show that when applied to a completely random and independent data, the model could not extract any rules and that it is only possible to extract them if the data has consistent expression patterns. This novel strategy can be used for predictive reverse engineering combinatorial expression rules from single-cell data and could help identify candidate transcription regulatory processes.

Channelpedia: an integrative and interactive database for ion channels

Ion channels are membrane proteins that selectively conduct ions across the cell membrane. The flux of ions through ion channels drives electrical and biochemical processes in cells and plays a critical role in shaping the electrical properties of neurons. During the past three decades, extensive research has been carried out to characterize the molecular, structural, and biophysical properties of ion channels. This research has begun to elucidate the role of ion channels in neuronal function and has subsequently led to the development of computational models of ion channel function. Although there have been substantial efforts to consolidate these findings into easily accessible and coherent online resources, a single comprehensive resource is still lacking. The success of these initiatives has been hindered by the sheer diversity of approaches and the variety in data formats. Here, we present “Channelpedia” (http://channelpedia.net), which is designed to store information related to ion channels and models and is characterized by an efficient information management framework. Composed of a combination of a database and a wiki-like discussion platform Channelpedia allows researchers to collaborate and synthesize ion channel information from literature. Equipped to automatically update references, Channelpedia integrates and highlights recent publications with relevant information in the database. It is web based, freely accessible and currently contains 187 annotated ion channels with 45 Hodgkin–Huxley models.

Intrinsic morphological diversity of thick-tufted layer 5 pyramidal neurons ensures robust and invariant properties of in silico synaptic connections

The morphology of neocortical pyramidal neurons is not only highly characteristic but also displays an intrinsic diversity that renders each neuron morphologically unique. We investigated the significance of this intrinsic morphological diversity in in silico networks composed of thick-tufted layer 5 (TTL5) pyramidal neurons, by comparing the in silico and in vitro properties of TTL5 synaptic connections. The synaptic locations of in silico connections were determined by placing 3D reconstructed TTL5 neurons randomly in a volume equivalent to that of layer 5 in the juvenile rat somatosensory cortex and using a 'collision-detection' algorithm to identify the incidental loci of axo-dendritic overlap. The activation time of the modelled synapses and their biophysical properties were characterized based on experimental measurements. We found that the anatomical loci of synapses and the physiological properties of the somatically recorded EPSPs closely matched those recorded experimentally without the need for any fine-tuning. Furthermore, perturbations to both the physiological or anatomical parameters of the model did not alter the average physiological properties of the population of modelled synaptic connections. This microcircuit-level robust behaviour was due to the intrinsic diversity of the morphology of pyramidal neurons in the microcircuit. We conclude that synaptic transmission in a network of TTL5 neurons is highly invariant across microcircuits suggesting that intrinsic diversity is a mechanism to ensure the same average synaptic properties in different animals of the same species. Finally, we show that the average physiological properties of the TTL5 microcircuit are surprisingly robust to anatomical and physiological perturbations also partly due to the intrinsic diversity of pyramidal neuron morphology.

Sleep homeostasis and cortical synchronization: I. Modeling the effects of synaptic strength on sleep slow waves

STUDY OBJECTIVES

Sleep slow-wave activity (SWA, electroencephalogram [EEG] power between 0.5 and 4.0 Hz) is homeostatically regulated, increasing with wakefulness and declining with sleep. Sleep SWA is thought to reflect sleep need, but the mechanisms of its homeostatic regulation remain unknown. Based on a recent hypothesis, we sought to determine whether a decrease in cortical synaptic strength can account for changes in sleep SWA.

DESIGN

A large-scale computer model of the sleeping thalamocortical system was used to reproduce in detail the cortical slow oscillations underlying EEG slow waves.

SETTING

N/A.

PATIENTS OR PARTICIPANTS

N/A.

INTERVENTIONS

Simulated reductions in the strength of corticocortical synapses.

MEASUREMENTS AND RESULTS

Decreased synaptic strength led to (1) decreased single cell membrane potential oscillations and reduced network synchronization, (2) decreased rate of neural recruitment and decruitment, and (3) emergence of local clusters of synchronized activity. These changes were reflected in the local EEG as (1) decreased incidence of high-amplitude slow waves, (2) decreased wave slope, and (3) increased number of multipeak waves. Spectral analysis confirmed that these changes were associated with a decrease in SWA.

CONCLUSIONS

A decrease in cortical synaptic strength is sufficient to account for changes in sleep SWA and is accompanied by characteristic changes in slow-wave parameters. Experimental results from rat cortical depth recordings and human high-density EEG show similar changes in slow-wave parameters with decreasing SWA, suggesting that the underlying mechanism may indeed be a net decrease in synaptic strength.

Thrombophlebitis of the great saphenous vein – recommendations for treatment

Objectives

The purpose of this study was to evaluate the incidence of great saphenous vein (GSV) thrombosis in symptomatic patients and its possible relationship to complications usually attributed to deep venous thrombosis (DVT).

Methods

To quantitate the frequency of GSV thrombosis and evaluate its possible morbidity, we reviewed all the venous studies, both inpatient and outpatient, at a Level I Trauma Center over one year. The charts of all patients who had a thrombus in the GSV, either alone or in combination with a DVT, were examined.

Results

A total of 2646 lower extremity venous scans were done in the year studied. In this group, there were 388 (14.5%) positive studies for a DVT. There were 36 (9.3%) patients in this group who had a DVT of the lower extremity and a thrombus in the GSV. In the total group, there were 30 patients (1.1%) with a superficial thrombophlebitis of the GSV alone. In these patients, 22 (73%) either showed cephalad progression of the thrombus, symptoms of shortness of breath, a mobile tip in the thrombus or extension of the thrombus into the common femoral vein. Five patients (16.6%), after failing medical therapy (heparin, bed rest and antibiotics), underwent surgical treatment.

Conclusions

Thrombophlebitis of the GSV, although not very common, needs to be carefully followed with a repeat duplex scan to determine if there is propagation of the thrombus. This study shows that thrombophlebitis of the GSV can cause many of the complications attributed to deep venous thrombi and, therefore, must be thoroughly evaluated, followed, and, if necessary, treated.

Can vacuum assisted venous drainage be achieved using a roller pump in an emergency? A pilot study using neonatal circuitry

There has been much advancement in perfusion technology over its 50 years of progression. One of these techniques is vacuum-assisted venous drainage (VAVD). Many perfusionists augment venous drainage using VAVD, typically from a wall vacuum source. This study explores alternates to providing VAVD if the wall vacuum fails. In two porcine laboratories, approximately 36 in. of 3/16-in. tubing was connected to a sucker return port and placed into the roller head next to the arterial pump. The vacuum was monitored with a DLP pressure monitoring system (Medtronic). This system was connected to small-bore tubing and attached to a stopcock on top of the reservoir. The vacuum was regulated using another stopcock connected to a non-filtered luer lock port on top of the reservoir or by a segment of 3 x 0.25-in.-diameter tubing attached to the vent port with a c-clamp. Vacuum drainage was achieved, ranging from -18 mmHg to -71 mmHg by manipulating the stopcock or c-clamp. Changes in venous drainage were seen by volume fluctuations in the venous reservoir. The vacuum was adjusted to account for dramatic changes. Augmented venous drainage using a roller pump can be achieved successfully during cardiopulmonary bypass (CPB). This method of active drainage can be used in lieu of wall suction or during times of emergency if wall suction fails.

Effect of storage and postage on recovery and quantitation of bacteria in sputum samples

AIMS

The aims of the study were to compare bacterial recovery following storage of sputum samples at 20 degrees C room temperature and 4 degrees C (refrigerated) for 24 h, and to determine the effect of postage on viable bacterial numbers.

METHODS

A total of 38 individual sputum samples from clinically stable patients with bronchiectasis were split into three equal aliquots and quantitative bacterial culture was performed (i) immediately, (ii) following storage at 4 degrees C for 24 h or (iii) following storage at 20 degrees C for 24 h. A further 42 sputum samples were split into two equal aliquots and quantitative bacterial culture was performed either immediately or following postage back to the laboratory by first-class mail from an outside location.

RESULTS

The predominant organism could still be recovered following storage at 4 degrees C and 20 degrees C, but viable numbers were significantly reduced following storage at 4 degrees C (p<0.004) by at least an order of magnitude (10-fold) in 24% of samples stored at 4 degrees C compared with only 8% stored at 20 degrees C. Posting samples back to the laboratory did not affect the recovery of bacterial species and there was no difference in viable numbers isolated.

CONCLUSIONS

The results suggest that storage at room temperature is preferable to refrigeration as it retains the species isolated and the viable number. The data also confirm that sputum samples can be posted to the laboratory from patients in the community without affecting qualitative or quantitative results.

Spatial and temporal operation of the Scotia Sea ecosystem: a review of large-scale links in a krill centred food web

The Scotia Sea ecosystem is a major component of the circumpolar Southern Ocean system, where productivity and predator demand for prey are high. The eastward-flowing Antarctic Circumpolar Current (ACC) and waters from the Weddell-Scotia Confluence dominate the physics of the Scotia Sea, leading to a strong advective flow, intense eddy activity and mixing. There is also strong seasonality, manifest by the changing irradiance and sea ice cover, which leads to shorter summers in the south. Summer phytoplankton blooms, which at times can cover an area of more than 0.5 million km2, probably result from the mixing of micronutrients into surface waters through the flow of the ACC over the Scotia Arc. This production is consumed by a range of species including Antarctic krill, which are the major prey item of large seabird and marine mammal populations. The flow of the ACC is steered north by the Scotia Arc, pushing polar water to lower latitudes, carrying with it krill during spring and summer, which subsidize food webs around South Georgia and the northern Scotia Arc. There is also marked interannual variability in winter sea ice distribution and sea surface temperatures that is linked to southern hemisphere-scale climate processes such as the El Niño-Southern Oscillation. This variation affects regional primary and secondary production and influences biogeochemical cycles. It also affects krill population dynamics and dispersal, which in turn impacts higher trophic level predator foraging, breeding performance and population dynamics. The ecosystem has also been highly perturbed as a result of harvesting over the last two centuries and significant ecological changes have also occurred in response to rapid regional warming during the second half of the twentieth century. This combination of historical perturbation and rapid regional change highlights that the Scotia Sea ecosystem is likely to show significant change over the next two to three decades, which may result in major ecological shifts.

Modelling Southern Ocean ecosystems: krill, the food-web, and the impacts of harvesting

The ecosystem approach to fisheries recognises the interdependence between harvested species and other ecosystem components. It aims to account for the propagation of the effects of harvesting through the food-web. The formulation and evaluation of ecosystem-based management strategies requires reliable models of ecosystem dynamics to predict these effects. The krill-based system in the Southern Ocean was the focus of some of the earliest models exploring such effects. It is also a suitable example for the development of models to support the ecosystem approach to fisheries because it has a relatively simple food-web structure and progress has been made in developing models of the key species and interactions, some of which has been motivated by the need to develop ecosystem-based management. Antarctic krill, Euphausia superba, is the main target species for the fishery and the main prey of many top predators. It is therefore critical to capture the processes affecting the dynamics and distribution of krill in ecosystem dynamics models. These processes include environmental influences on recruitment and the spatially variable influence of advection. Models must also capture the interactions between krill and its consumers, which are mediated by the spatial structure of the environment. Various models have explored predator-prey population dynamics with simplistic representations of these interactions, while others have focused on specific details of the interactions. There is now a pressing need to develop plausible and practical models of ecosystem dynamics that link processes occurring at these different scales. Many studies have highlighted uncertainties in our understanding of the system, which indicates future priorities in terms of both data collection and developing methods to evaluate the effects of these uncertainties on model predictions. We propose a modelling approach that focuses on harvested species and their monitored consumers and that evaluates model uncertainty by using alternative structures and functional forms in a Monte Carlo framework.

Modeling the Effects of Transcranial Magnetic Stimulation on Cortical Circuits

Transcranial magnetic stimulation (TMS) is commonly used to activate or inactivate specific cortical areas in a noninvasive manner. Because of technical constraints, the precise effects of TMS on cortical circuits are difficult to assess experimentally. Here, this issue is investigated by constructing a detailed model of a portion of the thalamocortical system and examining the effects of the simulated delivery of a TMS pulse. The model, which incorporates a large number of physiological and anatomical constraints, includes 33,000 spiking neurons arranged in a 3-layered motor cortex and over 5 million intra- and interlayer synaptic connections. The model was validated by reproducing several results from the experimental literature. These include the frequency, timing, dose response, and pharmacological modulation of epidurally recorded responses to TMS (the so-called I-waves), as well as paired-pulse response curves consistent with data from several experimental studies. The modeled responses to simulated TMS pulses in different experimental paradigms provide a detailed, self-consistent account of the neural and synaptic activities evoked by TMS within prototypical cortical circuits.

Exercise training and inspiratory muscle training in patients with bronchiectasis

BACKGROUND

Bronchiectasis is a chronic suppurative lung disease often characterised by airflow obstruction and hyperinflation, and leading to decreased exercise tolerance and reduced health status. The role of pulmonary rehabilitation (PR) and inspiratory muscle training (IMT) has not been investigated in this group of patients.

METHODS

Thirty two patients with idiopathic bronchiectasis were randomly allocated to one of three groups: PR plus sham IMT (PR-SHAM), PR plus targeted IMT (PR-IMT), or control. All patients (except the control group) underwent an 8 week training programme of either PR or PR plus targeted IMT. Exercise training during PR was performed three times weekly at 80% of the peak heart rate. IMT was performed at home for 15 minutes twice daily over the 8 week period.

RESULTS

PR-SHAM and PR-IMT resulted in significant increases in the incremental shuttle walking test of 96.7 metres (95% confidence interval (CI) 59.6 to 133.7) and 124.5 metres (95% CI 63.2 to 185.9), respectively, and in endurance exercise capacity of 174.9% (95% CI 34.7 to 426.1) and 205.7% (95% CI 31.6 to 310.6). There were no statistically significant differences in the improvements in exercise between the two groups. Significant improvements in inspiratory muscle strength were also observed both in the PR-IMT group (21.4 cm H2O increase, 95% CI 9.3 to 33.4; p = 0.008) and the PR-SHAM group (12.0 cm H2O increase, 95% CI 1.1 to 22.9; p = 0.04), the magnitude of which were also similar (p = 0.220). Improvements in exercise capacity were maintained in the PR-IMT group 3 months after training, but not in the PR-SHAM group.

CONCLUSION

PR is effective in improving exercise tolerance in bronchiectasis but there is no additional advantage of simultaneous IMT. IMT may, however, be important in the longevity of the training effects.

Multicenter experience with perventricular device closure of muscular ventricular septal defects

Hybrid procedures are becoming increasingly important, especially in the management of congenital heart lesions for which there are no ideal surgical or interventional options. This report describes a multicenter experience with perventricular muscular venticular septal defect (VSD) device closure. Three groups of patients (n = 12) were identified: infants with isolated muscular VSDs (n = 2), neonates with aortic coarctation and muscular VSDs (n = 3) or patients with muscular VSDs and other complex cardiac lesions (n = 2), and patients with muscular VSDs and pulmonary artery bands (n = 5). Via a sternotomy or a subxyphoid approach, the right ventricle (RV) free wall was punctured under transesophageal echocardiography guidance. A guidewire was introduced across the largest defect. A short delivery sheath was positioned in the left ventricle cavity. An Amplatzer muscular VSD occluding device was deployed across the VSD. Cardiopulmonary bypass was needed only for repair of concomitant lesions, such as double-outlet right ventricle, aortic coarctation, or pulmonary artery band removal. No complications were encountered using this technique. Discharge echocardiograms showed either mild or no significant shunting across the ventricular septum. At a median follow-up of 12 months, all patients were asymptomatic and 2 patients had mild residual ventricular level shunts. Perventricular closure of muscular VSDs is safe and effective for a variety of patients with muscular VSDs.

Evaluation of the AMPLATZER vascular plug for embolization of peripheral vascular malformations associated with congenital heart disease

OBJECTIVE

The purpose of this study is to evaluate the recently FDA-approved AMPLATZER Vascular Plug in the embolization of vascular lesions associated with congenital heart disease (CHD).

BACKGROUND

Fistulas and arteriovenous malformations have been occluded using various devices. The AMPLATZER Vascular Plug is a self-expandable, cylindrical device, used for embolization in the peripheral vasculature.

METHODS

A total of 84 vessels in 52 patients with CHD from 11 centers were occluded with 89 AMPLATZER Vascular Plugs, delivered through a coronary guide catheter in various vascular sites, including collaterals, pulmonary arterio-venous and coronary artery fistulas, transhepatic tracts, central shunts, patent ductus arteriosus (PDA), and excluded hepatic vein. Complete vessel occlusion was demonstrated within 10 min in 94% of patients.

RESULTS

There was no device embolization, vascular disruption, or procedure-related complication. One vascular plug implanted in a large type C PDA required surgical removal followed by PDA ligation, after 5 weeks from successful implant because of significant residual flow through the device.

CONCLUSIONS

The AMPLATZER Vascular Plug is an effective transcatheter occlusion device in the embolization of a wide variety of vascular lesions associated with CHD. Based on our early experience, caution should be used when considering the Vascular Plug as a closure device for large PDA.

Sleep Homeostasis in Drosophila Melanogaster

STUDY OBJECTIVES

The fruit fly Drosophila melanogaster is emerging as a promising model system for the genetic dissection of sleep. As in mammals, sleep in the fruit fly is a reversible state of reduced responsiveness to the external world and has been defined using an array of behavioral, pharmacologic, molecular, and electrophysiologic criteria. A central feature of mammalian sleep is its homeostatic regulation by the amount of previous wakefulness. Dissecting the mechanisms of homeostatic regulation is likely to provide key insights into the functions of sleep. Thus, it is important to establish to what extent sleep homeostasis is similar between mammals and flies. This study was designed to determine whether in flies, as in mammals, (1) sleep rebound is dependent on prior time awake; (2) sleep deprivation affects the intensity, in addition to the duration, of sleep rebound; (3) sleep loss impairs vigilance and performance; (4) the sleep homeostatic response is conserved among different wild-type lines, and between female and male flies of the same line.

DESIGN

Motor activity of individual flies was recorded at 1-minute intervals using the infrared Drosophila Activity Monitoring System during 2 baseline days; during 6, 12, and 24 hours of sleep deprivation; and during 2 days of recovery. Sleep was defined as any period of uninterrupted behavioral immobility lasting > 5 minutes. Sleep continuity was measured by calculating the number of brief awakenings, the number and duration of sleep episodes, and a sleep continuity score. Vigilance before and after sleep deprivation was assessed by measuring the escape response triggered by 2 different aversive stimuli.

SETTING

Fly sleep research laboratory at UW-Madison.

PARTICIPANTS AND INTERVENTIONS

Adult flies of the Canton-S (CS) strain and 116 other wild-type lines (> or = 16 female and > or = 16 male flies per line).

MEASUREMENTS AND RESULTS

In wild-type CS flies, as in mammals, the amount of sleep recovered after sleep deprivation was dependent on prior time awake. Relative to baseline sleep, recovery sleep in CS flies was less fragmented, with longer sleep episodes, and was associated with a higher arousal threshold. Sleep deprivation in CS flies also reduced performance. Sleep duration and continuity increased after 24 hour of sleep deprivation in all the other wild-type lines tested.

CONCLUSION

The sleep homeostatic response in fruit flies is a stable phenotype and shares most of, if not all, the major features of mammalian sleep homeostasis, thus supporting the use of Drosophila as a model system for the genetic dissection of sleep mechanisms and functions.

Resolution of bronchial inflammation is related to bacterial eradication following treatment of exacerbations of chronic bronchitis

BACKGROUND

Recent studies of the role of bacteria in chronic bronchitis have shown that bacterial colonisation is associated with enhanced inflammation and that purulent acute exacerbations of chronic bronchitis (AECB) are associated with bacteria and characterised by increased inflammation. Changes in bronchial inflammation in response to the success or failure of bacterial eradication following AECB were therefore studied.

METHODS

Bacterial quantitative culture and sputum markers of inflammation (myeloperoxidase (MPO), neutrophil elastase, leukotriene B4 (LTB4), sol:serum albumin ratio, and secretory leukoprotease inhibitor) were measured in patients presenting with culture positive purulent AECB and repeated 10 days and 2 months later. 41 patients provided sputum sufficient for both bacteriology and assessment of inflammation at baseline and day 10, and 46 provided sufficient sample for bacteriology, 40 of which could also be analysed for inflammation at 2 months (when clinically stable).

RESULTS

At day 10, 17 of the 41 patient samples had a positive bacterial culture. In the stable state, 18 of the 46 samples had a positive culture, but with a significantly lower bacterial load than at presentation. Although there was no difference between the groups at presentation, the concentration of MPO was lower (p<0.05) in those in whom bacteria were eradicated by day 10 than in those with persisting bacteria. The LTB4 concentration was similarly lower (p<0.001) in those in whom bacteria were eradicated than in those with persistent bacteria. In the stable clinical state the concentrations of both MPO and LTB4 were lower in those in whom bacteria were eradicated than in patients with persisting bacteria.

CONCLUSION

Resolution of bronchial inflammation following AECB is related to bacterial eradication. Those in whom bacteria continue to be cultured in their sputum have partial resolution of inflammation which may reflect continued stimulation by the reduced bacterial load.

Haemophilus parainfluenzae infection of respiratory mucosa

The pathogenicity of Haemophilus parainfluenzae (Hpi) in the respiratory tract is unclear, in contrast to the accepted pathogenicity of its close relative non-typable H. influenzae. We have investigated the interaction of two Hpi isolates with the mucosa of adenoid and bronchial tissue organ cultures. The adherence of bacteria to the mucosa of organ cultures, the effect of broth culture filtrates on human nasal epithelium, and interleukin (IL)-8 production by A549 cell cultures was investigated. Hpi 4846 adhered infrequently in clusters of pleomorphic cocco-bacilli to areas of epithelial damage, mucus and unciliated cells in adenoid organ culture experiments at 24 h, but not bronchial mucosa. Hpi 3698 was seen in only one adenoid and no bronchial organ cultures at 24 h. In separate experiments, Hpi 3698 was cleared more rapidly from the centre of the adenoid organ culture and was not cultured at 24 h. Although not adhering to the mucosa at 24 h, Hpi 3698, but not Hpi 4846, caused an increase in the amount of epithelial damage in both types of organ culture. Broth culture filtrates of both strains caused immediate slowing of ciliary beat frequency that progressed, and disrupted epithelial integrity. Dialysed culture filtrates of both strains stimulated IL-8 production by A549 cells, with the culture filtrate of Hpi 3698 being most potent. We conclude that two strains of Hpi varied in their adherence to adenoid tissue, and neither adhered to bronchial tissue. These results lead us to speculate that Hpi is only likely to be a pathogen in the lower respiratory tract when impaired airway defences delay bacterial clearance.

The transition from viral to autoimmune myocarditis

Myocarditis offers a unique opportunity to study the factors contributing to its transition from a viral infection to an autoimmune disease. In this article, we review recent studies on the role of nitric oxide (NO), gamma interferon (IFN-gamma) and interleukin 12 (IL-12) in the progression from early (viral) to late (autoimmune) phases of myocarditis induced by Coxsackievirus B3 (CB3) in highly susceptible (A.CA) and moderately susceptible (B10.M) mice. NO plays a paradoxical role, being protective in early stages but detrimental later in the course of disease. Treatment with antibody to IFN-gamma reduced early disease, but had little effect on the severity of cardiac lesions at later times. Treatment with recombinant (r) IL-12 significantly reduced the autoimmune cardiac lesions in moderately susceptible B10.M mice, but had no measurable effect in highly susceptible A.CA animals. These studies provide evidence that the profile of inflammatory mediators produced early in the course of viral infection determines the later development of autoimmune disease.