Saturn's F ring is intermittently shepherded by Prometheus

One of the stranger planetary rings is Saturn's narrow, clumpy F ring, lying just outside the main rings, in a region disturbed by chaotic orbital dynamics. We show that the F ring has a stable "true core" that dominates its mass and is confined into discontinuous short arcs of particles larger than a few millimeters in radius. The more obvious micron-size particles seen in images, outlining and obscuring the true core, contribute only a small fraction of its mass. We found that these arcs of large particles orbit Saturn in a specific corotational resonance with the nearby 100-kilometer diameter ringmoon Prometheus, which stabilizes the F ring material and allows it to persist within the disturbed region for decades or longer. Toward the end of the observing period, a small chaotic glitch in the orbit of Prometheus temporarily disrupted the confinement, but the arcs seem to be able to adapt.

Swell and Destroy: A Metal-Organic Framework-Containing Polymer Sponge That Immobilizes and Catalytically Degrades Nerve Agents

Organophosphorus chemical warfare agents function as potent neurotoxins. Whilst the destruction of nerve agents is most readily achieved by hydrolysis, their storage and transport are hazardous and lethal in milligram doses, with any spillage resulting in fatalities. Furthermore, current decontamination and remediation measures are limited by a need for stoichiometric reagents, solvents, and buffered solutions, complicating the process for the treatment of bulk contaminants. Herein, we report a composite polymer material capable of rendering bulk VX unusable by immobilization within a porous polymer until a metal-organic framework (MOF) catalyst fully hydrolyzes the neurotoxin. This is an all-in-one capability that minimizes the use of multiple reagents, facilitated by a porous high internal phase emulsion-based polystyrene monolith housing an active zirconia MOF catalyst (MOF-808); the porous polymer absorbs and immobilizes the liquid agents, while the MOF enables hydrolysis. The dichotomous hierarchy of porous materials facilitates the containment and rapid hydrolysis of VX (>80% degradation in 8 h) in the presence of excess H₂O. This composite can further enable the hydrolysis of neat VX with reliance on ambient humidity (>95% in 11 days). Potentially, 4.5 kg of the composite can absorb, immobilize, and degrade the contents of a standard chemical drum/barrel (208 L, 55 gal) of the chemical warfare agent (CWA). We believe that this composite is the first example of what will be the go-to approach for CWA immobilization and degradation in the future. Furthermore, we believe that this demonstration of a catalytically reusable absorbent sponge provides a signpost for the development of similar materials where immobilization of a substrate in a catalytically active environment is desirable.

Synthesis and μ-Opioid Activity of the Primary Metabolites of Carfentanil

Carfentanil is a synthetic opioid significantly more potent than clinically prescribed fentanyl. The primary metabolites of carfentanil, generated from human liver microsomes, were structurally confirmed through chemical synthesis. The synthesized compounds were evaluated for μ-opioid receptor (MOR) functional activity. Of the six metabolites assayed, a major metabolite showed comparable activity to the parent opioid. Three other metabolites showed significant MOR functional activity. The availability of the metabolites could aid improvements in the analysis of biomedical samples obtained from suspected human exposures to carfentanil and development of treatment protocols.

Close-range remote sensing of Saturn's rings during Cassini's ring-grazing orbits and Grand Finale

Saturn's rings are an accessible exemplar of an astrophysical disk, tracing the Saturn system's dynamical processes and history. We present close-range remote-sensing observations of the main rings from the Cassini spacecraft. We find detailed sculpting of the rings by embedded masses, and banded texture belts throughout the rings. Saturn-orbiting streams of material impact the F ring. There are fine-scaled correlations among optical depth, spectral properties, and temperature in the B ring, but anticorrelations within strong density waves in the A ring. There is no spectral distinction between plateaux and the rest of the C ring, whereas the region outward of the Keeler gap is spectrally distinct from nearby regions. These results likely indicate that radial stratification of particle physical properties, rather than compositional differences, is responsible for producing these ring structures.

Microwave-assisted activation and modulator removal in zirconium MOFs for buffer-free CWA hydrolysis

A novel, facile and efficient method was developed for the activation of acetic acid modulated zirconium MOFs. The protocol involves briefly heating the material in water using microwave irradiation. MOF-808, DUT-84 and UiO-66 were all activated in this manner to remove the modulator and organic solvent from the framework post synthesis, with retention of MOF integrity post activation. The degree of activation was characterised by the use of TGA and NMR. The catalytic activity of the activated MOFs and their non-activated counterparts was investigated for chemical warfare agent (CWA) hydrolysis. Upon activation, an increase in the rate of hydrolysis was observed in the degradation of CWA simulant dimethyl 4-nitrophenyl phosphate (DMNP). MOF-808 and DUT-84 were also screened as catalysts for the hydrolysis of the V-series agent VM, with remarkable half-lives obtained for MOF-808 in the absence of any buffers. Currently employed MOF activation procedures involve the use of additional organic solvents post synthesis; we believe this method to be ideally efficacious for the organic desolvation of zirconium MOFs and removing modulator additives.

Investigating the breakdown of the nerve agent simulant methyl paraoxon and chemical warfare agents GB and VX using nitrogen containing bases

A range of nitrogen containing bases was tested for the hydrolysis of a nerve agent simulant, methyl paraoxon (MP), and the chemical warfare agents, GB and VX.

Poly High Internal Phase Emulsion for the Immobilization of Chemical Warfare Agents

We report a facile method for the absorption (characterized by the weight/weight swelling degree, Q) of a variety of chemical warfare agents (CWAs); including sulfur mustard (HD) (Q = 40) and V-series (VM, VX, i-Bu-VX, n-Bu-VX) of nerve agents (Q ≥ 45) and a simulant, methyl benzoate (Q = 55), through the use of a poly(styrene-co-vinyl benzyl chloride-co-divinylbenzene) lightly cross-linked poly high internal phase emulsion (polyHIPE). By varying the vinyl benzyl chloride (VBC) content and the volume of the internal phase of the precursor emulsion it is demonstrated that absorption is facilitated both by the swelling of the polymer and the uptake of liquid in the pores. In particular the sample prepared from a 95% internal emulsion water content showed rapid swelling (<5 min to total absorption) and the ability to swell both from a monolithic state and from a compressed state, making these systems ideal practical candidates for the rapid immobilization of CWAs.

Chromosome contacts in activated T cells identify autoimmune disease candidate genes

Background

Autoimmune disease-associated variants are preferentially found in regulatory regions in immune cells, particularly CD4⁺ T cells. Linking such regulatory regions to gene promoters in disease-relevant cell contexts facilitates identification of candidate disease genes.

Results

Within 4 h, activation of CD4⁺ T cells invokes changes in histone modifications and enhancer RNA transcription that correspond to altered expression of the interacting genes identified by promoter capture Hi-C. By integrating promoter capture Hi-C data with genetic associations for five autoimmune diseases, we prioritised 245 candidate genes with a median distance from peak signal to prioritised gene of 153 kb. Just under half (108/245) prioritised genes related to activation-sensitive interactions. This included IL2RA, where allele-specific expression analyses were consistent with its interaction-mediated regulation, illustrating the utility of the approach.

Conclusions

Our systematic experimental framework offers an alternative approach to candidate causal gene identification for variants with cell state-specific functional effects, with achievable sample sizes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-017-1285-0) contains supplementary material, which is available to authorized users.

Swellable functional hypercrosslinked polymer networks for the uptake of chemical warfare agents

Porous materials can be used as sorbents for the bulk uptake (and potential deactivation) of chemical warfare agents (CWAs).

Capture Hi-C reveals novel candidate genes and complex long-range interactions with related autoimmune risk loci

Genome-wide association studies have been tremendously successful in identifying genetic variants associated with complex diseases. The majority of association signals are intergenic and evidence is accumulating that a high proportion of signals lie in enhancer regions. We use Capture Hi-C to investigate, for the first time, the interactions between associated variants for four autoimmune diseases and their functional targets in B- and T-cell lines. Here we report numerous looping interactions and provide evidence that only a minority of interactions are common to both B- and T-cell lines, suggesting interactions may be highly cell-type specific; some disease-associated SNPs do not interact with the nearest gene but with more compelling candidate genes (for example, FOXO1, AZI2) often situated several megabases away; and finally, regions associated with different autoimmune diseases interact with each other and the same promoter suggesting common autoimmune gene targets (for example, PTPRC, DEXI and ZFP36L1).

There is evidence that a proportion of the polymorphisms identified by genome-wide association studies lie in enchancer regions. Here the authors use Capture Hi-C to investigate the interaction with targets in autoimmune disease, showing interactions can be long range and cell-type specific.

Natural Variation in Interleukin-2 Sensitivity Influences Regulatory T-Cell Frequency and Function in Individuals With Long-standing Type 1 Diabetes

Defective immune homeostasis in the balance between FOXP3+ regulatory T cells (Tregs) and effector T cells is a likely contributing factor in the loss of self-tolerance observed in type 1 diabetes (T1D). Given the importance of interleukin-2 (IL-2) signaling in the generation and function of Tregs, observations that polymorphisms in genes in the IL-2 pathway associate with T1D and that some individuals with T1D exhibit reduced IL-2 signaling indicate that impairment of this pathway may play a role in Treg dysfunction and the pathogenesis of T1D. Here, we have examined IL-2 sensitivity in CD4+ T-cell subsets in 70 individuals with long-standing T1D, allowing us to investigate the effect of low IL-2 sensitivity on Treg frequency and function. IL-2 responsiveness, measured by STAT5a phosphorylation, was a very stable phenotype within individuals but exhibited considerable interindividual variation and was influenced by T1D-associated PTPN2 gene polymorphisms. Tregs from individuals with lower IL-2 signaling were reduced in frequency, were less able to maintain expression of FOXP3 under limiting concentrations of IL-2, and displayed reduced suppressor function. These results suggest that reduced IL-2 signaling may be used to identify patients with the highest Treg dysfunction and who may benefit most from IL-2 immunotherapy.

Detection and correction of artefacts in estimation of rare copy number variants and analysis of rare deletions in type 1 diabetes

Copy number variants (CNVs) have been proposed as a possible source of ‘missing heritability’ in complex human diseases. Two studies of type 1 diabetes (T1D) found null associations with common copy number polymorphisms, but CNVs of low frequency and high penetrance could still play a role. We used the Log-R-ratio intensity data from a dense single nucleotide polymorphism (SNP) array, ImmunoChip, to detect rare CNV deletions (rDELs) and duplications (rDUPs) in 6808 T1D cases, 9954 controls and 2206 families with T1D-affected offspring. Initial analyses detected CNV associations. However, these were shown to be false-positive findings, failing replication with polymerase chain reaction. We developed a pipeline of quality control (QC) tests that were calibrated using systematic testing of sensitivity and specificity. The case–control odds ratios (OR) of CNV burden on T1D risk resulting from this QC pipeline converged on unity, suggesting no global frequency difference in rDELs or rDUPs. There was evidence that deletions could impact T1D risk for a small minority of cases, with enrichment for rDELs longer than 400 kb (OR = 1.57, P = 0.005). There were also 18 de novo rDELs detected in affected offspring but none for unaffected siblings (P = 0.03). No specific CNV regions showed robust evidence for association with T1D, although frequencies were lower than expected (most less than 0.1%), substantially reducing statistical power, which was examined in detail. We present an R-package, plumbCNV, which provides an automated approach for QC and detection of rare CNVs that can facilitate equivalent analyses of large-scale SNP array datasets.

Analysis of clothing and urine from Moscow theatre siege casualties reveals carfentanil and remifentanil use

On October 26, 2002, Russian Special Forces deployed a chemical aerosol against Chechen terrorists to rescue hostages in the Dubrovka theatre. Its use confirmed Russian military interest in chemicals with effects on personnel and caused 125 deaths through a combination of the aerosol and inadequate medical care. This study provides evidence from liquid chromatography-tandem mass spectrometry analysis of extracts of clothing from two British survivors, and urine from a third survivor, that the aerosol comprised a mixture of two anaesthetics--carfentanil and remifentanil--whose relative proportions this study was unable to identify. Carfentanil and remifentanil were found on a shirt sample and a metabolite called norcarfentanil was found in a urine sample. This metabolite probably originated from carfentanil.

Sensitivity, specificity, and predictive power of the "Brief Risk-resilience Index for SCreening," a brief pan-diagnostic web screen for emotional health

Few standardized tools are available for time-efficient screening of emotional health status across diagnostic categories, especially in primary care. We evaluated the 45-question Brief Risk-resilience Index for SCreening (BRISC) and the 15-question mini-BRISC in identifying poor emotional health and coping capacity across a range of diagnostic groups - compared with a detailed clinical assessment - in a large sample of adult outpatients. Participants 18-60 years of age (n = 1079) recruited from 12 medical research and clinical sites completed the computerized assessments. Three index scores were derived from the full BRISC and the mini-BRISC: one for risk (negativity-positivity bias) and two for coping (resilience and social capacity). Summed answers were converted to standardized z-scores. BRISC scores were compared with detailed health assessment and diagnostic interview (for current psychiatric, psychological, and neurological conditions) by clinicians at each site according to diagnostic criteria. Clinicians were blinded to BRISC scores. Clinical assessment stratified participants as having "clinical" (n = 435) or "healthy" (n = 644) diagnostic status. Receiver operating characteristic analyses showed that a z-score threshold of -1.57 on the full BRISC index of emotional health provided an optimal classification of "clinical" versus "healthy" status (sensitivity: 81.2%, specificity: 92.7%, positive predictive power: 80.2%, and negative predictive power: 93.1%). Comparable findings were revealed for the mini-BRISC. Negativity-positivity bias index scores contributed the most to prediction. The negativity-positivity index of emotional health was most sensitive to classifying major depressive disorder (100%), posttraumatic stress disorder (95.8%), and panic disorder (88.7%). The BRISC and mini-BRISC both offer a brief, clinically useful screen to identify individuals at risk of disorders characterized by poor emotion regulation, from those with good emotional health and coping.

International Study to Predict Optimized Treatment for Depression (iSPOT-D), a randomized clinical trial: rationale and protocol

Background

Clinically useful treatment moderators of Major Depressive Disorder (MDD) have not yet been identified, though some baseline predictors of treatment outcome have been proposed. The aim of iSPOT-D is to identify pretreatment measures that predict or moderate MDD treatment response or remission to escitalopram, sertraline or venlafaxine; and develop a model that incorporates multiple predictors and moderators.

Methods/Design

The International Study to Predict Optimized Treatment - in Depression (iSPOT-D) is a multi-centre, international, randomized, prospective, open-label trial. It is enrolling 2016 MDD outpatients (ages 18-65) from primary or specialty care practices (672 per treatment arm; 672 age-, sex- and education-matched healthy controls). Study-eligible patients are antidepressant medication (ADM) naïve or willing to undergo a one-week wash-out of any non-protocol ADM, and cannot have had an inadequate response to protocol ADM. Baseline assessments include symptoms; distress; daily function; cognitive performance; electroencephalogram and event-related potentials; heart rate and genetic measures. A subset of these baseline assessments are repeated after eight weeks of treatment. Outcomes include the 17-item Hamilton Rating Scale for Depression (primary) and self-reported depressive symptoms, social functioning, quality of life, emotional regulation, and side-effect burden (secondary). Participants may then enter a naturalistic telephone follow-up at weeks 12, 16, 24 and 52. The first half of the sample will be used to identify potential predictors and moderators, and the second half to replicate and confirm.

Discussion

First enrolment was in December 2008, and is ongoing. iSPOT-D evaluates clinical and biological predictors of treatment response in the largest known sample of MDD collected worldwide.

Trial registration

International Study to Predict Optimised Treatment - in Depression (iSPOT-D) ClinicalTrials.gov Identifier: NCT00693849

URL: http://clinicaltrials.gov/ct2/show/NCT00693849?term=International+Study+to+Predict+Optimized+Treatment+for+Depression&rank=1

An investigation of EEG, genetic and cognitive markers of treatment response to antidepressant medication in patients with major depressive disorder: a pilot study

The aim of this study was to investigate if biomarkers in QEEG, genetic and neuropsychological measures are suitable for the prediction of antidepressant treatment outcome in depression. Twenty-five patients diagnosed with major depressive disorder were assessed twice, pretreatment and at 8-wk follow-up, on a variety of QEEG and neuropsychological tasks. Additionally, cheek swab samples were collected to assess genetic predictors of treatment outcome. The primary outcome measure was the absolute decrease on the HAM-D rating scale. Regression models were built in order to investigate which markers contribute most to the decrease in absolute HAM-D scores. Patients who had a better clinical outcome were characterized by a decrease in the amplitude of the Auditory Oddball N1 at baseline. The 'Met/Met' variant of the COMT gene was the best genetic predictor of treatment outcome. Impaired verbal memory performance was the best cognitive predictor. Raised frontal Theta power was the best EEG predictor of change in HAM-D scores. A tentative integrative model showed that a combination of N1 amplitude at Pz and verbal memory performance accounted for the largest part of the explained variance. These markers may serve as new biomarkers suitable for the prediction of antidepressant treatment outcome.

The effects of a poor night sleep on mood, cognitive, autonomic and electrophysiological measures

Sustained sleep problems such as insomnia have been shown to be detrimental to health. This study examines the less understood, finer grained effects of a single bad night's sleep on mood, cognitive, autonomic and electrophysiological functions. We assessed 338 individuals who had no symptoms of a clinical sleep disorder. Of these, 226 individuals had six or more hours sleep and 112 individuals had less than six hours sleep prior to an assessment of mood, cognition, autonomic and electrophysiological functioning. Individuals in the relatively "bad night" sleep group had higher depression, anxiety, and stress scores and reported significantly poorer overall wellbeing. They made more errors on simple cognitive tasks while more complex task components were unaffected. They also had an increase in heart rate and EEG alpha and beta power at rest. Participants in this study had no symptoms of a clinical sleep disorder, however the effects of a poor night sleep on measures of mood, cognition, autonomic and electrophysiological function were similar, but less severe than those reported in insomnia patients. The integrative profile of measures reported here point to an increase in physiological arousal and sub-optimal cognition, following a poor night's sleep.

An "integrative neuroscience" platform: application to profiles of negativity and positivity bias

The aim of the paper is to describe a standardized "Integrative Neuroscience" Platform that can be applied to elucidate brain-body mechanisms. This infrastructure includes a theoretical integration (the INTEGRATE Model). To demonstrate this infrastructure, hypotheses from the INTEGRATE Model are applied in an example investigation of the cognitive, brain and body markers of individual differences in the trait characteristic of Negativity Bias (the tendency to see oneself and one's world as negative). A sample of 270 healthy participants (18-65 years old) were grouped into equal sized matched subsets of high "Negativity Bias" and high "Positivity Bias" (n = 135 in each group). Participants were assessed using a standardized battery of psychological traits, cognition and brain and body (autonomic) activity. Greater "Negativity Bias" relative to "Positivity Bias" was characterized by greater autonomic reactivity and early neural excitation to signals of potential danger, at the timescale of Emotion (< 200 ms). Concomitantly, there was a relatively lower level of "Thinking", reflected in cognitive dimensions and associated electrical brain measures of working memory and EEG Theta power. By contrast, Negativity and Positivity Bias did not differ in levels of emotional resilience and social skills at the longer time scale of Self Regulation. This paper provides a demonstration of how an Integrative Neuroscience infrastructure can be used to elucidate the brain-body basis of trait characteristics, such as Negativity Bias, that are key indicators of risk for poor well-being and psychopathology.

Chemical coding and central projections of gastric vagal afferent neurons

Vagal afferents that innervate gastric muscle or mucosa transmit distinct sensory information from their endings to the nucleus of the tractus solitarius (NTS). While these afferent subtypes are functionally distinct, no neurochemical correlate has been described and it is unknown whether they terminate in different central locations. This study aimed to identify gastric vagal afferent subtypes in the nodose ganglion (NG) of ferrets, their terminal areas in NTS and neurochemistry for isolectin-B4 (IB4) and calcitonin gene-related peptide (CGRP). Vagal afferents were traced from gastric muscle or mucosa and IB4 and CGRP labelling assessed in NG and NTS. 7 +/- 1% and 6 +/- 1% of NG neurons were traced from gastric muscle or mucosa respectively; these were more likely to label for CGRP or for both CGRP and IB4 than other NG neurons (P < 0.01). Muscular afferents were also less likely than others to label with IB4 (P < 0.001). Less than 1% of NG neurons were traced from both muscle and mucosa. Central terminals of both afferent subtypes occurred in the subnucleus gelatinosus of the NTS, but did not overlap completely. This region also labelled for CGRP and IB4. We conclude that while vagal afferents from gastric muscle and mucosa differ little in their chemical coding for CGRP and IB4, they can be traced selectively from their peripheral endings to NG and to overlapping and distinct regions of NTS. Thus, there is an anatomical substrate for convergent NTS integration for both types of afferent input.

Use of evidence in economic decision models: practical issues and methodological challenges

This paper outlines the current 'state of play' regarding the use of evidence in decision modelling and highlights both practical issues and methodological challenges related to identifying, combining and reporting evidence to inform decision model parameters and structure. Based on discussions at two MRC HSRC-funded workshops consisting of 37 experts from a range of disciplines (i.e. decision-makers, health economists, information specialists, operations researchers and statisticians), it aims to derive a multi-disciplinary standpoint on the appropriate use of evidence in economic decision models and, where applicable, offer some suggestions for good modelling practice. Gaps in the established methodology knowledge base are identified for future research.

Meta-analysis of mixed treatment comparisons at multiple follow-up times

Mixed treatment comparisons (MTC) meta-analysis is a methodology for making inferences on relative treatment effects based on a synthesis of both direct and indirect evidence on multiple treatment contrasts. This is particularly useful in the context of cost-effectiveness analysis and medical decision making. Here, we extend these methods to a more complex situation where trials report results at one or more, different yet fixed, follow-up times. These methods are applied to an illustrative data set combining evidence on healing rates under six different treatments for gastro-esophageal reflux disease (GERD). A series of Bayesian hierarchical models based on piece-wise exponential hazards is developed that borrow strength across the MTC networks and also across time points. These include models for absolute and relative treatment effects, models with fixed or random effects over time, random walk models, and models with homogeneous or heterogeneous between-trials variation. The deviance information criterion (DIC) is used to guide model development and selection. Models for absolute treatment effects generate materially different rankings of the treatments than models that separate the trial-specific baselines from the relative treatment effects. The extent of between-trials heterogeneity in treatment effects depends on treatment contrast. In discussion we note that models of this type have a very wide potential application.

An integrative approach to determine the best behavioral and biological markers of methylphenidate

AIMS

To distinguish the most sensitive markers of methylphenidate (MPH) effects on behavior and underlying biology using an integrated cognitive and brain function test battery.

METHODS

A randomized placebo-controlled trial with 32 healthy adult males. Subjects were tested on MPH doses across 18 sessions with subjective mood, objective behavioral and biological endpoints. From a computerized battery of tests, behavioral measures were cognitive performance scores, while biological measures of brain function included electroencephalographs (EEG) and event-related potentials (ERPs) with complementary measures of autonomic arousal. Using mixed modeling analyses; we determined which measures were most affected by MPH dose and correlation analyses determined the associations among them.

RESULTS

MPH dose had the most pronounced effect on cognitive performance (sustained attention/vigilance), baseline autonomic arousal (heart rate, blood pressure) and baseline brain activity (EEG theta power). The faster reaction time, reduced errors, increased autonomic arousal and reductions in theta showed strong to moderate inter-correlations. MPH least affected subjective mood measures and early sensory ERP components.

DISCUSSION

These findings suggest that MPH increases cortical and autonomic arousal, facilitating vigilance. The combination of behavioral and biological measures may provide an objective set of markers of MPH response.

INTEGRATIVE SIGNIFICANCE

This approach has provided additional insight into the mechanism of the stimulant medication, MPH, which would not be achieved by using such measures in isolation.

The contribution of apolipoprotein E alleles on cognitive performance and dynamic neural activity over six decades

Neuroimaging shows brain-functional differences due to apolipoprotein E (APOE) polymorphisms may exist decades before the increased risk period for Alzheimer's disease, but little is known about their effect on cognition and brain function in children and young adults. This study assessed 415 healthy epsilon2 and epsilon4 carriers and matched epsilon3/epsilon3 controls, spanning ages 6-65, on a range of cognitive tests. Subjects were also compared on a new dynamical measure of EEG activity during a visual working memory task using alphabetical stimuli. epsilon4 subjects had better verbal fluency compared to epsilon3, an effect that was strongest in 51-65 year-olds. No epsilon4 deficits in cognition were found. In 6-15 year-olds, there were differences in total spatio-temporal wave activity between epsilon3 and epsilon4 subjects in the theta band, approximately 200ms post-stimulus. Differences in brain function in younger epsilon4 subjects and superior verbal fluency across the entire age range suggest that the APOE epsilon4 allele is an example of antagonistic pleiotropy.

BRAIN STRUCTURE AND FUNCTION CORRELATES OF GENERAL AND SOCIAL COGNITION

AIMS

To examine how general (e.g., memory, attention) and social (emotional and interpersonal processes) cognition relate to measures of brain function and structure.

METHODS

PCA was used to identify general and social cognitive factors from Brain Resource International Database in 1,316 subjects. The identified factors were correlated with each subject's corresponding brain structure (MRI) and function (EEG/ERP) data.

RESULTS

Seven core cognitive factors were identified for general and three for social. General cognition was correlated with global grey matter, while social cognition was negatively correlated with grey matter in fronto-temporal-somatosensory regions. Executive function, information processing speed and verbal memory performance were correlated with delta-theta qEEG, while most general cognitive factors negatively correlated with beta qEEG. Faster information processing speed was correlated with alpha qEEG. Executive function and information processing speed was correlated with negative-going ERP amplitude and slower ERP latency at frontal sites, but at posterior sites negative correlations were found.

DISCUSSION

In contrast to general cognition, social cognition is identified by different functional (automated) activity and more localized neural structures. Only general cognition, requiring more effortful, controlled processing is related to brain function measures, particularly in frontal cortices.

INTEGRATIVE SIGNIFICANCE

Recording measures from multiple modalities including MRI, EEG/ERP, social and general cognition within the same subject provides a method of brain profiling for use in cognitive-neurotherapy and pharmacological studies.

The impact of diabetes on current revascularisation practice and clinical outcome in patients with critical lower limb ischaemia

OBJECTIVE

To compare current revascularisation practice and outcome in diabetic and non-diabetic patients presenting with critical limb ischaemia (CLI) to a single vascular surgeon.

METHODS

Data for 113 patients presenting with CLI were collected prospectively over a 3-year period. Forty-four (39%) were diabetic. Treatment was classified as percutaneous angioplasty, arterial reconstruction, primary major amputation, and conservative therapy. Main outcome measures were 30-day mortality, major amputation, survival, and amputation-free survival.

RESULTS

Diabetic patients were more likely to present with gangrene, give a history of angina, be treated with nitrates and statins, and have lower cholesterol levels. No significant differences were found in the initial treatment options between diabetics and non-diabetics: angioplasty 39 vs 26%, surgical revascularisation 34 vs 33%, primary major amputation 9% vs 17%, and conservative treatment 11 vs 19% (p = ns in all). There were eight deaths (7%) within 30-days. At follow-up (1-44 months, median 14 months), rates of major amputation and death for the entire population were 23 and 8%, respectively. The 12-month cumulative survival and amputation-free survival rates were 90 and 72%, respectively. When comparing diabetic to non-diabetic patients, there were no significant differences in the 30-day mortality (6.8 vs 7.2%, p = 0.4), cumulative survival (93 vs 89% at 12 months, log-rank test: 0.00, p = 0.9), amputation-free survival (71 vs 73% at 12 months, log-rank test: 0.00, p = 0.99), and major amputation rates (22.7 vs 23.1% at 12 months, p = 0.96). Similarly, there were no differences in limb salvage rates between diabetic and non-diabetic patients undergoing revascularisation procedures (78 vs 90% at 12 months, log-rank test: 2.04, p = 0.15).

CONCLUSIONS

In current practice, an aggressive multidisciplinary approach in diabetic patients presenting with CLI leads to similar limb salvage, amputation-free survival, mortality, and major amputation rates to those seen in non-diabetic patients. The presence of diabetes should not deter clinicians from attempting revascularisation by means of angioplasty or surgical reconstruction.

The cost-effectiveness of influenza vaccination of healthy adults 50–64 years of age

Influenza can cause significant morbidity and mortality. Influenza vaccination is an effective and safe strategy in the prevention of influenza. Currently the National Health Service (NHS) vaccinates 'at-risk' individuals only. This definition includes everyone over 65 years of age but excludes individuals 50-64 years of age unless they have an additional risk factor, such as underlying heart disease or lung disease. In order to examine the cost-effectiveness of an extension of the vaccination policy to include this age group we constructed an economic model to estimate the costs and benefits of vaccination from both a health service and a societal perspective. Data to populate the model was obtained from the literature and the outcome measure used was the quality adjusted life year (QALY). Influenza vaccination prevented an estimated 4508 cases (95% CI: 2431-7606) per 100,000 vaccinees per influenza season for a net cost to the NHS of pound653,221 (95% CI: 354,575-1,072,257). The net cost increased to pound1,139,069 (95% CI 27,052-2,030,473) when non-NHS costs were included and the estimated cost-per-QALY were pound6174 and pound10,766 for NHS and all costs respectively. Extension of the current immunisation policy has the potential to generate a significant health benefit at a comparatively low cost.

The dose-dependent effect of methylphenidate on performance, cognition and psychophysiology

The effects of methylphenidate (MPH) on 32 healthy human male volunteers (aged 18 to 25 years, mean age=22.26) were examined using a within-subject design. Each participant attended six testing periods, held once per week. Within each testing period, three repeat testing sessions were undertaken: pre-medication, on-medication and two hours post-medication. In these sessions, dose was manipulated (placebo, 5 mg, 15 mg or 45 mg) according a double-blind placebo design. In this report, we focus on behavioral, autonomic arousal (heart rate, skin conductance) and psychophysiological (ERP) data acquired during the working memory task. We found increased autonomic arousal (heart rate, skin conductance and blood pressure) with MPH. A linear reduction in reaction time, omission errors and target P3 latency, and a corresponding increase in background P3 amplitude was observed with increased MPH dose. The relationship between these measures supported an increase in performance and underlying brain function with MPH. To our knowledge, this is the first paper to use behavioral, arousal and electrophysiological measures in an integrative approach to study the effects of MPH on healthy adults.

PREDICTING STIMULANT MEDICATION RESPONSE IN ADHD: EVIDENCE FROM AN INTEGRATED PROFILE OF NEUROPSYCHOLOGICAL, PSYCHOPHYSIOLOGICAL AND CLINICAL FACTORS

There have been significant advances in understanding the neurobiology of Attention-Deficit/Hyperactivity Disorder (ADHD) and it is timely to examine the ability of biological and psychological markers to predict medication response in this disorder. We evaluated prediction of medication response in adolescent ADHD using neuropsychological testing and psychophysiological measures of central and autonomic function. Fifty ADHD adolescents participated in pre- and post-stimulant medication testing. Separately ranked performance in auditory oddball and visual Working Memory (WM) tasks determined 20 "responders" and 20 "non-responders" with 10 "neutrals" excluded from the discriminant function analyses (DFA). For both oddball and WM performance rankings, the two groups did not differ in age, sex, or handedness. However, responders did have higher levels of symptomatology than non-responders at baseline. Pre-stimulant medication psychophysiology variables were used as predictors in each DFA. Oddball performance correctly classified 85.0% of responders and 95.0% of non-responders. Better response was associated with increased resting beta power (left posteriorly), delayed oddball target N1 (frontally), decreased oddball target P2 (left posteriorly) and decreased WM distractor P3 (right frontally). Working memory performance classified 80.0% of responders and 90.0% of non-responders, with a broadly similar profile of psychophysiological predictors. These finding indicate the value of integrating neuropsychological and psychophysiological data in predicting medication response in ADHD.

TOWARD AN INTEGRATED PROFILE OF EMOTIONAL INTELLIGENCE: INTRODUCING A BRIEF MEASURE

Over the last decade, an increasing number of research studies have focused on the construct of Emotional Intelligence (EI), which may be broadly defined as the capacity to perceive and regulate emotions in oneself as well as those of others. Researchers have generally adopted an organizational or management focus to the study of EI, however studies which adopt a more integrated perspective by combining psychological with biological measures, may help in further elucidating this relatively abstract construct. The first objective of this paper was to report on the psychometric properties of a brief, self-report measure of EI (Brain Resource Inventory for Emotional intelligence Factors or BRIEF), comprising internal emotional capacity (IEC), external emotional capacity (EEC) and self concept (SELF). Second, we further explored the validity of the measure by assessing the relationships between the BRIEF and variables considered relevant to the understanding of EI (including gender, age, personality, cognitive intelligence and resting state electroencephalography, EEG). The BRIEF possessed sound psychometric properties (internal consistency, r=0.68-0.81; test-retest reliability, r=0.92; construct validity with the Self Report Emotional Intelligence Test, r=0.70). As hypothesized, females were found to score higher than males on EI. EI was associated more with personality than with cognitive ability, and EEG was found to explain a significant portion of the variance in EI scores. The finding that low EI is related to underarousal of the left-frontal cortex (increased theta EEG) is consistent with research on patients with depression, as well as attention deficit hyperactivity disorder. Although EI did not display age-related increases, this might relate to the exclusion of adolescents from our sample. In conclusion, examination of the way in which EI measures relate to a complementary range of psychological and biological measures may help to further elucidate this construct.

The cost of clinically significant urinary storage symptoms for community dwelling adults in the UK

OBJECTIVES

To estimate the cost of clinically significant urinary storage symptoms (CSUSS), including costs borne by the National Health Service (NHS) and individuals, in terms of the use of goods and services in community-dwelling adults.

SUBJECTS AND METHODS

The subjects were community-dwelling adults aged >/= 40 years and living in Leicestershire. The prevalence of CSUSS was estimated using a postal questionnaire with a randomly selected sample of 23 182 respondents. The costs associated with CSUSS were estimated using home interviews with 613 cases with and 523 subjects without CSUSS. Cases were defined on the basis of urinary symptoms of leakage, urgency, frequency and nocturia. Willingness-to-pay was used to measure intangible costs as an indicator of the value of alleviating symptoms.

RESULTS

The estimated total annual cost to the NHS for treating CSUSS cases in community-dwelling adults was pound 536 million at 1999/2000 prices ( pound 303 million and pound 233 million for men and women, respectively). The total value of costs borne by individuals was estimated to be pound 207 million ( pound 29 million and pound 178 million for men and women, respectively). This gives total annual costs related to the use of services of pound 743 million. There were large intangible costs borne by individuals estimated to be pound 669 million ( pound 301 and pound 368 million for men and women) for the UK in terms of willingness-to-pay.

CONCLUSIONS

The costs of CSUSS in the community amounted to approximately 1.1% of overall NHS spending for 1999/2000. Personally borne and intangible costs are also large and important components of the costs of CSUSS. There are large gender differences in the proportion of costs borne by the NHS, i.e. 91% of male and 57% of female costs.

Trial introduction of the Willis dropped ovary technique for spaying cattle in northern Australia

OBJECTIVE

To compare the Willis dropped ovary technique with traditional spaying methods in extensive beef cattle herds in northern Australia.

PROCEDURE

Three field trials were conducted simultaneously at different sites in northern Australia in 1996-97. Brahman and Brahman-Shorthorn cross heifers (n = 219, 2 years, 250 to 378 kg) and cows (n = 211, 3 to 16 years, 256 to 540 kg) were allocated by stratified randomisation to three treatments: spaying using the Willis dropped ovary technique (WDOT); spaying using traditional paralumbar and vaginal methods; and unspayed. Following these procedures, these nonpregnant, nonlactating cattle were then exposed to bulls (4 per 100 females) under extensive rangeland conditions for 12 months during which time weight, body condition, pregnancy and ovarian function were monitored and compared.

RESULTS

Pregnancy rates varied from 60 to 90% for entire heifers and 80 to 100% for entire cows depending on site. The traditional spay methods were 100% successful in preventing pregnancy; the WDOT was 92 to 97% effective, depending on operator experience. The number of deaths was the same or higher in Willis spayed animals than other groups. Weight changes were similar in all groups at the three sites over the trial period. The time taken to spay using the WDOT was similar to or less than that required for the traditional methods. Uterine abnormalities were not observed in animals spayed with the WDOT, there were however 30 (12.4%) animals where excision of the ovary was incomplete; the still-attached ovarian remnant presumably accounting for the three pregnant animals in this group.

CONCLUSION

The WDOT suffers from requiring a high degree of skill in transrectal ovarian manipulation. There were more deaths and more pregnancies than with traditional spay methods. More experienced operators can be expected to achieve lower mortalities, better contraception and higher processing rates. Pregnancy will occur as a consequence of ovarian remnants unless care is taken to ensure removal of the entire ovary.

The post-operative mortality of ruptured abdominal aortic aneurysm repair

INTRODUCTION

Late peri-operative death after ruptured abdominal aortic aneurysm (RAAA) repair is usually due to multiple-organ failure. The aim of this study was to identify any factors that are associated with mortality in this group of patients.

METHODS

A retrospective case-note review of a single decade's operative experience of RAAA repair in a single centre. Only those patients with confirmed rupture at laparotomy were included. Sixty-three pre- intra- and post-operative variables were recorded where possible for each patient who survived surgery and the initial 24-hours post-operatively. Multi-variate analysis was performed using stepwise logistic regression. The P-POSSUM, RAAA-POSSUM, RAAA-POSSUM (physiology only), V-POSSUM, and V-POSSUM (physiology only) models were all compared to determine how each performed in these patients.

RESULTS

Two hundred and twenty-three cases of confirmed RAAA were identified, of whom 139 survived the operation and initial 24-hours post-operatively. In-hospital mortality in this group of patients was 32.4%. Variables significantly associated with mortality after multi-variate analysis, were low intra-operative systolic blood pressure, the presence of a consultant anaesthetist at the initial operation and the development of cardiac, renal or gastro-intestinal complications. All POSSUM models except the V-POSSUM and P-POSSUM (physiology only) models demonstrated no significant lack of fit in this dataset.

DISCUSSION

Factors associated with delayed peri-operative death after RAAA are not the same as those previously found to be associated with overall peri-operative mortality after RAAA repair.

Meta-analysis of randomized clinical trials comparing open and laparoscopic inguinal hernia repair

BACKGROUND

The aim was to conduct a meta-analysis of the randomized evidence to determine the relative merits of laparoscopic (LIHR) and open (OIHR) inguinal hernia repair.

METHODS

A search of the Medline, Embase, Science Citation Index, Current Contents and PubMed databases identified all randomized clinical trials that compared OIHR and LIHR and were published in the English language between January 1990 and the end of October 2000. The meta-analysis was prepared in accordance with the Quality of Reporting of Meta-analyses (QUOROM) statement. The six outcome variables analysed were operating time, time to discharge from hospital, return to normal activity and return to work, postoperative complications and recurrence rate. Random effects meta-analyses were performed using odds ratios and weighted mean differences.

RESULTS

Twenty-nine trials were considered suitable for meta-analysis. Some 3017 hernias were repaired laparoscopically and 2972 hernias were repaired using an open method in 5588 patients. For four of the six outcomes the summary point estimates favoured LIHR over OIHR; there was a significant reduction of 38 per cent in the relative odds of postoperative complications (odds ratio 0.62 (95 per cent confidence interval (c.i.) 0.46 to 0.84); P = 0.002), 4.73 (95 per cent c.i. 3.51 to 5.96) days in time to return to normal activity (P < 0.001), 6.96 (95 per cent c.i. 5.34 to 8.58) days in time to return to work (P < 0.001) and 3.43 (95 per cent c.i. 0.35 to 6.50) h in time to discharge from hospital (P = 0.029). There was a significant increase of 15.20 (95 per cent c.i. 7.78 to 22.63) min in the mean operating time for LIHR (P < 0.001). The relative odds of short-term recurrence were increased by 50 per cent for LIHR compared with OIHR, although this result was not statistically significant (odds ratio 1.51 (95 per cent c.i. 0.81 to 2.79); P = 0.194).

CONCLUSION

LIHR was associated with earlier discharge from hospital, quicker return to normal activity and work, and significantly fewer postoperative complications than OIHR. However, the operating time was significantly longer and there was a trend towards an increase in the relative odds of recurrence after laparoscopic repair.

Decision analytical economic modelling within a Bayesian framework: application to prophylactic antibiotics use for caesarean section

Economic evaluation of health care interventions based on decision analytic modelling can generate valuable information for health policy decision makers. However, the usefulness of the results obtained depends on the quality of the data input into the model; that is, the accuracy of the estimates for the costs, effectiveness, and transition probabilities between the different health states of the model. The aim of this paper is to review the use of Bayesian decision models in economic evaluation and to demonstrate how the individual components required for decision analytical modelling (i.e., systematic review incorporating meta-analyses, estimation of transition probabilities, evaluation of the model, and sensitivity analysis) may be addressed simultaneously in one coherent Bayesian model evaluated using Markov Chain Monte Carlo simulation implemented in the specialist Bayesian statistics software WinBUGS. To illustrate the method described, a simple probabilistic decision model is developed to evaluate the cost implications of using prophylactic antibiotics in caesarean section to reduce the incidence of wound infection. The advantages of using the Bayesian statistical approach outlined compared to the conventional classical approaches to decision analysis include the ability to: (i) perform all necessary analyses, including all intermediate analyses (e.g., meta-analyses) required to derive model parameters, in a single coherent model; (ii) incorporate expert opinion either directly or regarding the relative credibility of different data sources; (iii) use the actual posterior distributions for parameters of interest (opposed to making distributional assumptions necessary for the classical formulation); and (iv) incorporate uncertainty for all model parameters.

Total costs and predictors of costs in individuals with early inflammatory polyarthritis: a community-based prospective study

OBJECTIVE

To estimate the health service, non-health service and total costs and predictors of costs in individuals with early inflammatory polyarthritis (IP).

METHODS

We conducted a prospective longitudinal study over a 6-month period. The participants were a random sample of 133 individuals who had enrolled with the community-based Norfolk Arthritis Register (NOAR) database between 1994 and 1999. The main outcome measures were the mean (per person) 6-month health service cost, non-health-service cost and total cost associated with IP.

RESULTS

One hundred and fifteen of the 133 individuals who were recruited into the study completed 6 months of follow-up. The mean 6-month total cost was estimated to be 2800 pounds sterling per person, of which 14% was health service costs and the remainder non-health-service costs. Higher total costs were associated with lower health status and rheumatoid factor positivity.

CONCLUSIONS

Early IP has a considerable impact on both the health-care system and, more importantly, society. Non-health-service costs (i.e. costs incurred by the individual with the disease, their family and friends) account for a substantial proportion (86%) of the total costs associated with early IP.

Bull selection and use in northern Australia. 5. Social behaviour and management

Calf output of bulls was derived using DNA typing for paternity following multiple-sire mating at two sites in northern Australia. At Swan's Lagoon Beef Cattle Research Station, 12, mixed-age, Brahman cross bulls were continuously mated with an average of 325 females in a 22km2 open-savannah paddock. Water was available in two troughs. Behaviour of the bulls and location of cows were monitored. At Kamilaroi Station, 2- to 2.5-year-old Brahman bulls were introduced to the study. Twenty-four bulls (HIGH%) were mated in an 84km2 paddock for 3.5 months to 411 heifers in 1995/1995 and for 4.5 months to 350 heifers and 320 first-lactation cows in 1995/1996. A second group of 10 bulls (LOW%) selected on reproductive soundness was mated concurrently in a neighbouring 60km2 paddock to 411 heifers in 1995/1995 and to 350 heifers and 298 first-lactation cows in 1995/1996. In each paddock in both years, 300-350 females were expected to cycle during mating. Both paddocks were flat and semi-forested and water was available only at troughs. At both sites, detailed physical and reproductive examinations of all bulls were conducted prior to and post-mating.Calf output of individual bulls was highly variable but repeatable (r=0.6-0.7) between years. Up to 90% of the 270-380 calves resulting from each mating were sired by between 6 and 8 bulls. Reducing from 3.7 to 2.8% bulls:females at Swan's Lagoon did not delay conceptions. At Kamilaroi, reproductively sound bulls achieved an estimated 5-6 conceptions per week over the peak mating period when sufficient cycling females were available. Differences in pregnancy rates between paddocks appeared due to differences in nutrition and it appeared that conceptions were not delayed with LOW% vs. HIGH% bulls. Variance between bulls in calf output was substantially lower when fewer bulls were used. Bull attrition occurred each year in the HIGH% paddock but not in the LOW% paddock. Calf output was unrelated to body condition of bulls. Seven of the 12 bulls in one 2-year period at Swan's Lagoon appeared to restrict their movement range to 250-750ha for 90-100% of the time. These ranges expanded when the bull:female ratio was reduced. Only one of the nine bulls remained within a 500ha home range for at least 85% of the time during peak mating in 1998 at 2.8% bulls:females. In previous years with 3.7% bulls:females, up to eight of the 12 bulls had remained within a 500ha home range for 85% of the time. Bull behaviour related to high calf output included restricted movement range, grazing with females at a majority of observations, stable social behaviour, and social dominance. These observations demonstrate that multiple-sire mating of reproductively sound Brahman and Brahman-derived bulls at 2.5% of cycling females will not jeopardise herd fertility under extensive management in northern Australia.

GABA(B)R expressed on vagal afferent neurones inhibit gastric mechanosensitivity in ferret proximal stomach

GABA(B)-receptor (GABA(B)R) agonists reduce transient lower esophageal sphincter relaxation (TLESR) and reflux episodes through an action on vagal pathways. In this study, we determined whether GABA(B)R are expressed on vagal afferent neurones and whether they modulate distension-evoked discharge of vagal afferents in the isolated stomach. Vagal mehanoreceptor activity was recorded following distensions of the isolated ferret proximal stomach before and after perfusion with the GABA(B)R-selective agonists baclofen and 3-aminopropylphosphinic acid (3-APPiA). Retrograde labeling and immunohistochemistry were used to identify GABA(B)R located on vagal afferent neurones in the nodose ganglia. Vagal afferent fibers responded to isovolumetric gastric distension with an increase in discharge. The GABA(B)-receptor agonists baclofen (5 x 10(-5) M) and 3-APPiA (10(-6) to 10(-5) M) but not muscimol (GABA(A)-selective agonist: 1.3 x 10(-5) M) significantly decreased afferent distension-response curves. The effect of baclofen (5 x 10(-5) M) was reversed by the GABA(B)-receptor antagonist CGP 62349 (10(-5) M). Over 93% of retrogradely labeled gastric vagal afferents in the nodose ganglia expressed immunoreactivity for the GABA(B)R. GABA(B)R expressed on vagal afferent fibers directly inhibit gastric mechanosensory activity. This is likely a contributing mechanism to the efficacy of GABA(B)-receptor agonists in reducing TLESR and reflux episodes in vivo.

Glycoconjugates on the surface of epididymal spermatozoa in a marsupial, the brushtail possum, Trichosurus vulpecula

Variation in localization and distribution of saccharides on the sperm surface of a marsupial, the brushtail possum, Trichosurus vulpecula, was compared between spermatozoa from the caput and cauda epididymides. Spermatozoa were subjected to the following treatments: (i) unfixed and fixed spermatozoa were stained with fluorescein-labelled lectins; (ii) unfixed spermatozoa were incubated with lectins for determination of agglutination; and (iii) spermatozoa were incubated with detergent to remove the plasmalemma, the glycoproteins were separated on SDS-PAGE and western blots were stained with biotinylated lectins. Many of the fluorescein isothiocyanate (FITC)-labelled lectins bound selectively to the sperm surface, and marked differences were found in lectin staining affinity between caput and cauda epididymal spermatozoa. Incubation of spermatozoa from the cauda epididymidis with neuraminidase reversed many of the differences in staining of the cauda epididymal spermatozoa, indicating masking of some terminal saccharides by sialic acid. Agglutination of spermatozoa from the caput epididymidis occurred after incubation with Concanavalin A (ConA) and soybean agglutinin (SBA), but agglutination was less extensive for spermatozoa from the cauda epididymidis. Western blot analysis indicated several ConA-positive bands in caput sperm extracts, but fewer positive bands in the cauda sperm extracts, whereas SBA stained four bands from caput but none from the cauda epididymal spermatozoa. These results demonstrate extensive glycosylation of the surface proteins of spermatozoa from the caput epididymidis and significant differences in spermatozoa from the cauda epididymidis. In general, the findings indicate similar glycosylation of the surface of marsupial spermatozoa to those from eutherian mammals despite marked differences in their morphology and early divergence of marsupials from eutherian mammals. It would appear that this situation differs markedly from that in sub-mammalian vertebrates.

Contraceptive efficacy of an intra-uterine device in Brahman cattle

The contraceptive efficacy of an intra-uterine device was evaluated using 218 heifers and 212 cows on three north Australian cattle stations. The heifers were aged approximately 2 years and weighed 250-378 kg; the cows were aged 3-16 years and weighed 256-540 kg. All cattle were non-pregnant, non-lactating Brahmans. At the end of the monsoon (wet) season (April-June 1997), the cattle were allocated by stratified randomisation to the three treatments which were untreated controls (n=59), surgical ovariectomy (n=105), or implantation with a bovine intra-uterine device (BIUD; n=266). All cattle grazed and were managed as one group within each station. They were exposed to bulls (4 per 100 females) from soon after treatment until slaughter approximately 12 months later. The BIUD could not be implanted in 25% of heifers and 8% of cows due to narrow or twisted cervices. Correct placement of the BIUDs appeared to be achieved in 57% of heifers and 72% of cows. At slaughter, the devices were incorrectly positioned in 73% of heifers and 49% of cows into which BIUDs had been inserted and that remained non-pregnant. Uterine perforations by the BIUD were observed in 35 and 45% of these heifers and cows, respectively; most perforations appeared to occur during implantation. Low-grade endometritis was observed at slaughter in most BIUD-implanted animals; 2% had pyometra.BIUD animals did not have significantly different growth to that of control or ovariectomised animals, other than when ovariectomy suppressed growth following surgery. Most animals implanted with BIUDs appeared to have normal ovarian function and animals were observed mating. All ovariectomised animals remained non-pregnant. Over 80% of controls were pregnant within 8 months of exposure to bulls, except heifers at one station where pregnancy rate was restricted to 25% as a result of severe nutritional conditions. Pregnancy was diagnosed in 21% of heifers and 33% of cows with implanted BIUDs. The device remained correctly positioned and with no pregnancy diagnosed in the year following implantation in only 2% of heifers and 14% of cows originally allocated. Because of the difficulties of implanting BIUDs, the high frequency of associated uterine injury, the high pregnancy rate in implanted animals, and that growth was unaffected by the presence of a BIUD, it was concluded that the device had poor contraception efficacy and no growth-promotant effect in Brahman cattle.

The use of narrative in the development of critical thinking

This paper describes an approach to assessment aimed at developing critical skills in the production of arguments concerning contemporary issues in health. It is demonstrated that, in teaching from a constructivist position of knowledge, students can be cautious in producing assignments because of the relativist characteristic of constructivism. It is proposed that students could be more open and flexible in their approach to assessment and the use of cooperative working through the creation of narratives. It is suggested that narratives can provide an accessible and heuristic process from which academic accounts may be built. The use of narratives in taking the students from their everyday thinking to academic accounts is presented in relation to four teaching sessions. The use of this approach is in turn evaluated by students' narratives of their learning experience. Of 30 narratives obtained from students, analysis demonstrated that 21 accounts expressed aspects associated with the development of critical thinking. Nine students voiced some dissatisfaction with the assessment process, and further work to remedy these problems is outlined.

Secondary health service care and second line drug costs of early inflammatory polyarthritis in Norfolk, UK

OBJECTIVE

To estimate the secondary health service care and second line drug costs (including drug monitoring costs) for a cohort of people with early inflammatory polyarthritis (IP) and the subgroup classified as having rheumatoid arthritis (RA) recruited to a population based register.

METHODS

The study population consisted of 344 people with IP who had enrolled on the Norfolk Arthritis Register (NOAR) in 1990-91, an average of 24 weeks after onset of their symptoms. Utilizing resource use data from NOAR, augmented by unit cost data from other sources, the average (per person) and cumulative secondary care and second line drug costs were estimated for Years 1, 2, 3, 4, and 5 following registration with NOAR.

RESULTS

The total secondary health service care and second line drug costs were 472,125 (338,704 for RA subgroup) (1990-91 prices) over the 5 year study period, with inpatient stays, outpatient visits, and second line drugs accounting for 58, 9, and 33%, respectively. Nineteen percent of the study population neither visited hospital nor were prescribed second line drugs.

CONCLUSION

Overall, inpatient stay costs represented the largest proportion of secondary health service care and second line drug costs, making 21% of the total study cohort responsible for 80% of the total 5 year costs incurred.

Extratesticular sperm maturation in the brush-tail possum, Trichosurus vulpecula

The changes in distribution of protein and sugar components in, and on, the plasmalemma of the spermatozoon during epididymal transit of a marsupial, the brush-tail possum, Trichosurus vulpecula, are described. Freeze-fracture studies indicate a change in organization of plasmalemma intramembranous particles of both the head and midpiece of the tail as the spermatozoa pass from the caput to cauda epididymides. Staining with fluorescein isothiocyanate (FITC)-lectins shows, that heads of caput spermatozoa stain with Con A, WGA, RCA120, LCA and JAC, whereas those from the cauda epididymides stain only with LCA and JAC, thus suggesting that N-acetyl-beta-D-glucosamine, alpha-D-glucose, or beta-D-galactose may either become lost or masked during epididymal transit. A reduction of alpha-D-mannose is also suggested. Collectively these results show that the plasmalemma of the spermatozoon of at least this marsupial species undergoes both protein and saccharide modification during transit of the epididymis. How these findings relate to sperm maturation in preparation for sperm-egg binding has yet to be determined.

Economic burden of rheumatoid arthritis: a systematic review

OBJECTIVE

To summarize the state of knowledge with regard to the economic impact of rheumatoid arthritis (RA) and to highlight any weaknesses in the work conducted to date, so as to inform future RA cost-of-illness studies.

METHODS

Four computerized literature databases were searched to identify all the literature relevant to this review. Seven elements indicating a quality cost-of-illness study were established and used to appraise the literature identified critically. Where possible, costs reported by the different studies were converted to 1996 US dollars using the consumer price index for medical care.

RESULTS

Total average medical costs were reported to range from US$5720 (UK pound3575) to US$5822 (UK pound3638). Medication constituted between 8 and 24% of total medical costs, physician visits between 8 and 21%, and in-patient stays between 17 and 88%. The average number of days absent from work due to a person's RA was reported to range from 2.7 to 30 days/year.

CONCLUSION

The economic impact of RA in terms of cost was reported to be substantial by all studies reviewed. However, methodological problems meant that discrepancies in the average (per person) annual cost of RA existed across studies.

Protein synthesis and secretion by the epididymis of the brushtail possum, Trichosurus vulpecula

In this study of brushtail possums, proteins present in epididymal fluid and not present in blood plasma and those that become associated with spermatozoa as they pass along the tract were investigated. At least 19 proteins were present in epididymal fluid in the various regions of the tract that were not detected in serum. Some of these may be present on the sperm plasmalemma. Six proteins were extracted from caput spermatozoa (M(r) 117,000, 103,000, 87,500, 85,000, 62,000 and 33,000) that did not appear in the caudal sperm extracts. Eight proteins (M(r) 50,000, 49,000, 32,000, 27,000, 26,500, 25,000, 24,500 and 18,000) were localized to caudal sperm extracts. These findings suggest that some sperm proteins are lost or modified, whereas others are added to the sperm plasma membrane during epididymal transit. In vitro incorporation of [35S]methionine by the epididymal tissue showed that the distal caput and corpus are the most active regions in the synthesis and secretion of proteins. Four caudal epididymal proteins (M(r) 72,000, 31,000, 26,500 and 21,000) were partially sequenced. Those of M(r) 31,000 and 26,500 had the same N-terminal amino acid sequence suggesting post-translational modification of the same protein; they showed homology to a retinoic acid-binding protein. The protein of M(r) 72,000 was found to be homologous to alpha-fetoprotein, whereas the protein of M(r) 21,000 showed no significant homology to any protein in the database. These results show that the lumen of the epididymis has many proteins that are not present in the blood, some of which appear to become associated with spermatozoa during epididymal transit.

Neonatal screening for inborn errors of metabolism: cost, yield and outcome

OBJECTIVES. To systematically review the literature on inborn errors of metabolism, neonatal screening technology and screening programmes in order to analyse the costs and benefits of introducing screening based on tandem mass-spectrometry (tandem MS) for a wide range of disorders of amino acid and organic acid metabolism in the UK. To evaluate screening for cystic fibrosis, Duchenne muscular dystrophy and other disorders which are tested on an individual basis. HOW THE RESEARCH WAS CONDUCTED. Systematic searches were carried out of the literature on inborn errors of metabolism, neonatal screening programmes, tandem MS-based neonatal screening technology, economic evaluations of neonatal screening programmes and psychological aspects of neonatal screening. Background material on the biology of inherited metabolic disease, the basic philosophy, and the history and current status of the UK screening programme was also collected. Relevant papers in the grey literature and recent publications were identified by hand-searching. Each paper was graded. For each disease an aggregate grade for the state of knowledge in six key areas was awarded. Additional data were prospectively collected on activity and costs in UK neonatal screening laboratories, and expert clinical opinion on current treatment modalities and outcomes. These data were used to construct a decision-analysis model of neonatal screening technologies, comparing tandem MS with the existing phenylketonuria screening methods. This model determined the cost per additional case identified and, for each disease, the additional treatment costs per case, and the cost per life-year saved. All costs and benefits were discounted at 6% per annum. One-way sensitivity analysis was performed showing the effect of varying the discount rate, the incidence rate of each disorder, the number of neonates screened and the cost of tandem MS, on the cost per life-year gained. RESEARCH FINDINGS. The UK screening programmes for phenylketonuria and congenital hypothyroidism have largely achieved the expected objectives and are cost-effective. Current concerns are the difficulty of maintaining adequate coverage, perceived organisational weaknesses, and a lack of overview. For many of the organic acid disorders it was necessary to rely on data obtained from clinically-diagnosed cases. Many of these diseases can be treated very effectively and a sensitive screening test was available for most of the diseases. Except for cystic fibrosis, there have been no randomised controlled trials of the overall effectiveness of neonatal screening. Despite the anxiety generated by the screening process, there is strong parental support for screening. The effects of diagnosis through screening on subsequent reproductive behaviour is less clear. Conflicts exist between current concepts and the traditional principles of screening. The availability of effective treatment is not an absolute prerequisite: early diagnosis is of value to the family concerned and, to the extent that is leads to increased use of prenatal diagnosis, may help to reduce the overall burden of disease. Neonatal screening is also of value in diseases which present early but with non-specific symptoms. Indeed, almost all of the diseases considered could merit neonatal screening. The majority of economic evaluations failed to incorporate the health benefits from screening, and therefore failed to address the value of the information which the screening programmes provided to parents. The marginal cost of changing from present technology to tandem MS would be approximately 0.60 pounds per baby at a workload of 100,000 samples a year, and 0.87 pounds at 50,000 samples per year. The ability to screen for a wider range of diseases would lead to the identification of some 20 additional cases per 100,000 infants screened, giving a laboratory cost per additional diagnosis of 3000 pounds at an annual workload of 100,000 babies per year.(ABSTRACT TRUNCATED)

Creep feeding and prepartum supplementation effects on growth and fertility of Brahman-cross cattle in the dry tropics

Post-partum anoestrus is a primary contributor to low branding rates in Bos indicus cattle herds in the dry tropics of northern Australia [Entwistle, K. W. (1983). Australian Meat Research Committee Review No. 431. To increase branding rates, it was hypothesised that creep feeding for a short period in mid-late lactation during the latter half of the growing season may trigger an earlier onset of post-partum oestrus cycling, just as short-term, high-level, prepartum supplementation can achieve. Two experiments were conducted using Fn Brahman-cross cows (1/2, 5/8 and 3/4 crosses with Beef Shorthorn) which calved from late October to late Januarv. Cows were mated from mid-late Januarv to mid-April. Calves in one treatment in both experiments had ad libitum access to creep feed (calf pellets: 16% crude protein, 10 MJ ME/kg) for 4042 days from late February to early April. In experiment 2, the effects on cow growth and fertility due to supplementation with either cottonseed meal (1.5 kg/day) or molasses with 7.4% (w/w) urea for 49 days late in the dry season before calving ('spike' feeding) were also evaluated. Control cattle were unsupplemented. Creep feed was only consumed at 0.1 and 0.4 kg/day in experiments 1 and 2, respectively. Short-term creep feeding had no consistent effects on cow liveweights, condition, or fertility, or on calf growth and temperaments under extensive grazing conditions during the tropical wet season. Spike feeding reduced weight loss by 0.2-0.4 kg/day (P<0.01). The effects on liveweights did not persist into the wet season. There were no effects on cow fertility in this year of extreme weather conditions, when 4 months of nutritional and climatic stress followed supplementation.

An evaluation of visual assessment for fertility in Brahman cross cows using the Bonsma technique

A technique of visual assessment of cattle for reproductive efficiency, described by Professor Jan Bonsma of South Africa, was evaluated in two well-managed large herds of 1/2 to 3/4 Brahman cross heifers and cows located in the dry tropics of north Australia. Individual lifetime performance records were available for all animals. Experienced cattlemen carried out the assessments. Higher scores were previously claimed to indicate higher fertility. The technique had high repeatability (0.7) and was quickly learned by the assessors. Scores from visual assessment had no useful predictive value for either heifer or cow fertility or for growth rate up to 27 mo of age, although 2.5-yr-old heifers which were scored as subfertile matured into 4% smaller cows than heifers which had scored higher. Scores decreased as fatness increased (P < 0.05). Some biases in visual assessment occurred. Lactating cows scored higher than nonlactating cows (P < 0.05), independently of their reproductive record. Red and grey cows scored higher than brindle and black/brown cows (P < 0.05). Bonsma scores were not influenced by the percentage of Brahman in the genotype. Significant, but apparently random, age effects on scores also occurred. It was concluded that the visual assessment criteria described by Bonsma were of no practical value in assessing potential productivity of breeding animals in well-managed Brahman cross cattle in the dry tropics.