1311 FRAILTY IN RANDOMISED CONTROLLED TRIALS FOR DEMENTIA OR MILD COGNITIVE IMPAIRMENT

Background

Frailty and dementia have a bidirectional relationship. However, frailty is rarely reported in clinical trials for dementia and mild cognitive impairment (MCI) which limits assessment of trial applicability. This study aims to use a frailty index (FI) to measure frailty using individual participant data (IPD) from clinical trials for MCI and dementia and to quality the prevalence of frailty and its association with serious adverse events (SAEs) and trial attrition.

Methods

We analysed IPD from three dementia (n=1) and MCI (n=2) trials. An FI comprising physical deficits was created for each trial using baseline IPD. Poisson and logistic regression were used to examine associations with SAEs and attrition, respectively. Estimates were pooled in random effects meta-analysis. Analyses were repeated using an FI incorporating cognitive as well as physical deficits, and results compared.

Results

The mean physical FI was 0.13 and 0.14 in the MCI trials and 0.25 in the dementia trial. Frailty prevalence (FI>0.24) was 5.1%, 5.4% in MCI trials and 55.6% in dementia. After including cognitive deficits, prevalence was similar in MCI (4.6% and 4.9%) but higher in dementia (80.7%). 99th percentile of FI (0.29 in MCI, 0.44 in dementia) was lower than in most general population studies. Frailty was associated with SAEs (physical FI IRR = 1.63 [1.43, 1.87]; physical/cognitive FI IRR = 1.67 [1.45, 1.93]). Frailty was not associated with trial attrition (physical FI OR = 1.18 [0.92, 1.53]; physical/cognitive FI OR = 1.17 [0.92, 1.49]).

Conclusion

Measuring frailty from IPD in dementia and MCI trials is feasible. Severe frailty may be under-represented. Frailty is associated with clinically significant outcomes. Including only physical deficits may underestimate frailty in dementia. Frailty can and should be measured in trials for dementia and MCI, and efforts should be made to facilitate inclusion of people living with frailty.

802 CONCURRENT PATHOLOGIES OBSERVED IN OLDER ADULTS WITH COVID-19 INFECTION

Introduction

This study aimed to look at the effect of frailty and multi morbidity on short-term outcomes in patients diagnosed with COVID-19 in a hospital setting, looking specifically at the variety of concurrent pathologies diagnosed during their admission and how these affected the course of their illness and mortality.

Methods

The study took place at Glasgow Royal Infirmary. We retrospectively collected data from 280 patients who were admitted to the medicine for the elderly department between the 1st October and 1st December 2020 and diagnosed with COVID-19.

Results

In this cohort, 65% of older adults in hospital with COVID-19 had their admissions complicated by concurrent pathologies; most commonly delirium, acute kidney injury and pulmonary embolism, also increasing mortality in this group. It was also found that 39% of patients in this group had co-pathologies that were not necessarily associated with COVID-19 disease, for example AKI, AF and stroke/TIA. 35% of older adults in this group had no concurrent medical diagnoses during their admission, however this did not correlate with reduced mortality in this group.

Conclusion

The data highlights the vulnerability of older adults with COVID-19 infection making them more susceptible to concurrent disease and contributing to further morbidity and mortality. We also found a large number of patients had co-pathologies not associated with COVID-19 disease, highlighting the importance of considering other diagnoses in frail elderly patients.

European Stroke Organisation (ESO) standard operating procedure for the preparation and publishing of guidelines

The first European Stroke Organization (ESO) standard operating procedure (SOP) published in 2015 aimed at the implementation the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology to provide evidence-based guidelines for stroke management. This second ESO-SOP is aiming at further increase of the practicability of ESO guidelines and its technical implications. Authors comprised of the members of the ESO guideline Board and ESO Executive Committee. The final document was agreed on by several internal reviews. The second SOP comprises of the following aspects: rational for the SOP, the introduction of expert consensus statements, types of guideline documents, structures involved and detailed description of the guideline preparation process, handling of financial and intellectual conflicts of interest (CoI), involvement of ESO members in the guideline process, review process, authorship and publication policy, updating of guidelines, cooperation with other societies, and dealing with falsified data. This second SOP supersedes the first SOP published in 2015.

33 Diagnostic Test Accuracy of the 4AT for Delirium Detection: Systematic Review and Meta-Analysis

Introduction

Detection of delirium in hospitalised older adults is recommended in national and international guidelines. The 4 ‘A’s Test (4AT; www.the4AT.com) is a short (<2 min) instrument for delirium detection that is used internationally as a standard tool in clinical practice. We performed a systematic review and meta-analysis of diagnostic test accuracy of the 4AT for delirium detection.

Methods

We searched the following electronic databases through Ovid: MEDLINE, Embase, and PsycINFO. Additional databases were searched: CINAHL (EBSCOhost), clinicaltrials.gov and Cochrane Central Register of Controlled Trials from 2011 (4AT publication) until 21 December 2019. Inclusion criteria: older adults (≥65) across any setting of care except critical care; validation study of the 4AT against a delirium reference standard (standard diagnostic criteria or validated tool). Two reviewers independently screened abstracts and papers and performed the data extraction. Pooled estimates of sensitivity and specificity were generated from a bivariate random effects model.

Results

17 studies (n = 3,701 observations) were included. Various settings including acute medicine, surgery, stroke wards and the emergency department were represented. The overall prevalence of delirium was 24.2% (95% CI 17.8–32.1%; range 10.5–61.9%). The pooled sensitivity was 0.88 (95% CI 0.80–0.93) and the pooled specificity was 0.88 (95% CI 0.82–0.92). The methodological quality of studies was mostly good.

Conclusions

The 4AT is now supported by a substantial evidence base comparable to other well-studied tools such as the Confusion Assessment Method (CAM). The strong pooled sensitivity and specificity findings for the 4AT in this meta-analysis along with its brevity and lack of need for specific training provide support for its use as an effective assessment tool for delirium.

Atrial fibrillation and stroke outcomes in Scotland: real-world evidence from a contemporary, national dataset

Introduction

Atrial Fibrillation (AF) is an important cause of mortality and morbidity. The major risk of AF is stroke, which can be reduced through anticoagulation. The burden of stroke, and AF-related stroke, is particularly high in Scotland. It is often reported that AF-related stroke is associated with poorer outcomes than other stroke types, it is also thought to lead to an increased institutionalisation. Data supporting these observations are historic, but major advances in AF assessment and treatment could have changed outcome patterns. Real world evidence on outcomes, collected at scale, can give a useful measure of contemporary AF stroke outcomes.

Purpose

To assess whether stroke patients, with and without AF on admission, differ in terms of al-cause mortality, recurrence of stroke, and care home admission using contemporary large-scale observational data.

Methods

A retrospective cohort study linking national hospital, prescribing, care home and stroke audit data was conducted. The cohort, comprising patients ≥18 years of age with incident ischemic stroke between 2009 and 2017, was divided into three groups: AF-related stroke prescribed oral anticoagulant (OAC) pre-stroke event (AF-OAC Group); AF-related stroke not prescribed anticoagulant pre-stroke event (AF-noOAC Group); stroke with no prevalent or incident AF and no anticoagulation (comparator) (noAF-noOAC Group). Time-to-event analyses (adjusted for demographic and clinical characteristics) were conducted to estimate hazard ratios for recurrent stroke, all-cause mortality, and care-home admission with a follow-up time of two years.

Results

From a cohort of 64,159 incident ischemic strokes, 4,418 and 15,124 patients with AF were identified for groups AF-OAC and AF-noOAC, respectively. The remaining 44,617 patients belonged to group noAF-noOAC. An increasing number of incident strokes was observed with increasing age in each group up to 80–84 years. The risk of recurrent stroke was significantly greater in groups AF-OAC (HR 1.12 [95% CI 1.08,1.17]) and AF-noOAC (HR 1.05 [95% CI 1.03,1.08]) compared to noAF-noOAC group. An increased risk of all-cause mortality was observed in groups AF-OAC (HR 1.52 [95% CI 1.39,1.66]) and AF-noOAC (HR 1.59 [95% CI 1.51,1.68]) compared to the noAF-noOAC group. Patients in group AF-noOAC were more likely to be discharged to a care home following stroke (HR 1.37 [95% CI 1.23,1.52]) compared to patients in the other groups.

Conclusion

AF-related stroke is associated with poor outcomes, with significantly higher risks of recurrent stroke and all-cause mortality for patients with AF compared to non-AF stroke. Despite advances in AF care, our data suggest there is still potential to prevent a substantial proportion of disabling strokes through better identification and treatment of AF. These results must be interpreted with caution, as data take no account of treatment adherence, dosing or rationale for individual patient level prescribing decisions.

Funding Acknowledgement

Type of funding source: Private company. Main funding source(s): Bristol-Myers Squibb Research and Development

Has the proportion of patients diagnosed with myocardial infarction that receives a 12 ECG in the prehospital setting in the UK changed over time?

Background

Two thirds of patients with Acute Myocardial Infarction (AMI) arrive at hospital in the UK by ambulance, usually staffed by paramedics who routinely carry out 12 lead ECGs for patients with suspected heart attack. However, recent research found that prehospital ECGs were missing for 40% of these patients, with better survival prospects in those who had received one.

Purpose

We are investigating reasons for non-administration of 12 lead ECG for patients diagnosed with AMI, in order to develop an intervention to improve practice. Firstly we explored whether the proportion of patients with AMI that receive a prehospital ECG has changed over time.

Methods

Interrogation of national UK national heart attack register (MINAP) database, extraction of data related to patients brought by ambulance by year.

Results

The cohort of patients diagnosed with AMI and taken to hospital by ambulance ranged from 32410 in 2005 to 60265 in 2017; the proportion with a prehospital ECG increased steadily across this period, from 51% to 78%, an average increase of 1.9% per annum.

Conclusions

Evidence based guidelines supporting the use of 12 lead ECG by ambulance paramedics may have contributed to improvements in care. However, 1 in 5 patients brought to hospital by ambulance still does not receive an ECG prior to arrival, which we know compromises their survival prospects. In order to optimise care we need to establish whether non-administration is a question of misdiagnosis, patient refusal or lack of availability of trained crews/equipment.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Risk factors for incident delirium among urological patients: a systematic review and meta-analysis with GRADE summary of findings

Background

Post-operative delirium is an important, yet under-researched complication of surgery. Patients undergoing urological surgery may be at especially high risk of POD, as they are often older, and interventions can be associated with conditions that trigger delirium. The main aim of this systematic review was to evaluate the available evidence for risk factors in this patient group.

Methods

Five databases were searched (MEDLINE, Web of Science, EMBASE, CINAHL and PsychInfo) between January 1987 and June 2019. The Newcastle–Ottawa Scale was used to assess for risk of bias. Pooled odds ratio or mean difference (MD) for individual risk factors were estimated using the Mantel–Haenzel and inverse variance methods.

Results

Seven articles met the inclusion criteria, giving a total population of 1937. The incidence of POD ranged from 5 to 29%. Three studies were deemed low risk of bias and four at a high risk of bias. Nine risk factors were suitable for meta-analysis, with age (MD 4.314 95% CI 1.597, 7.032 p = 0.002) and the clock drawing test (MD − 2.443 95% CI − 3.029, − 1.857 p < 0.001) having a statistically significant association with POD in pooled analyses.

Conclusion

Delirium is common in urological patients. This review has identified a lack of studies in this surgical population, with wide heterogeneity and high risk of bias. It also highlights a number of potential risk factors for post-operative delirium, of which some are modifiable. However, the strength of evidence is weak at present and so future research should focus on assessing comparable risk factors in this patient group in order to inform future clinical practice.

Review registration The review protocol was prospectively registered with the PROSPERO database (reference CRD42017054613)

Post-admission outcomes of participants in the PARAMEDIC trial: A cluster randomised trial of mechanical or manual chest compressions

BACKGROUND

The PARAMEDIC cluster randomised trial evaluated the LUCAS mechanical chest compression device, and did not find evidence that use of mechanical chest compression led to an improvement in survival at 30 days. This paper reports patient outcomes from admission to hospital to 12 months after randomisation.

METHODS

Information about hospital length of stay and intensive care management was obtained through linkage with Hospital Episode Statistics and the Intensive Care National Audit and Research Centre. Patients surviving to hospital discharge were approached to complete questionnaires (SF-12v2, EQ-5D, MMSE, HADS and PTSD-CL) at 90days and 12 months. The study is registered with Current Controlled Trials, number ISRCTN08233942.

RESULTS

377 patients in the LUCAS arm and 658 patients in the manual chest compression were admitted to hospital. Hospital and intensive care length of stay were similar. Long term follow-up assessments were limited by poor response rates (53.7% at 3 months and 55.6% at 12 months). Follow-up rates were lower in those with worse neurological function. Among respondents, long term health related quality of life outcomes and emotional well-being was similar between groups. Cognitive function, measured by MMSE, was marginally lower in the LUCAS arm mean 26.9 (SD 3.7) compared to control mean 28.0 (SD 2.3), adjusted mean difference -1.5 (95% CI -2.6 to -0.4).

CONCLUSION

There were no clinically important differences identified in outcomes at long term follow-up between those allocated to the mechanical chest compression compared to those receiving manual chest compression.

Determinants of post-stroke cognitive impairment: analysis from VISTA

BACKGROUND

Post-stroke cognitive impairment (PSCI) occurs commonly and is linked with development of dementia. We investigated the relationship between demographic, clinical and stroke symptoms at stroke onset and the presence of PSCI at 1 and 3 years after stroke.

METHODS

We accessed anonymized data from the Virtual International Stroke Trial Archive (VISTA), including demographic and clinical variables. Post-stroke cognitive impairment was defined as a Mini-Mental State Examination (MMSE) score of ≤26. We assessed univariate relationships between baseline stroke symptoms and PSCI at 1 and 3 years following stroke, retaining the significant and relevant clinical factors as covariates in a final adjusted logistic regression model.

RESULTS

We analysed data on 5435 patients with recent (median 33 days) stroke or transient ischaemic attack (TIA). Mean (±SD) age was 62.6 (±12.6) years; 3476 (65%) patients were male. Follow-up data were available for 2270 and 1294 patients at 1 and 3 years, respectively. At 1 year, 781 (34%) patients had MMSE≤26; at 3 years, 391 (30%) had MMSE≤26. After adjusting for age, stroke severity, hypertension, diabetes and type of qualifying event, initial stroke impairment (leg paralysis) was associated with increased rate of PSCI at 1 year (OR=1.62; 95% CI=1.20-2.20) and at 3 years (OR=1.95; 95% CI=1.23-3.09). Associations were consistent on subgroup analysis restricted to ischaemic stroke and transient ischaemic attack (N=4992).

CONCLUSIONS

Besides well-known determinants of PSCI such as age, stroke severity and the presence of vascular risk factors, also leg paralysis is associated with subsequent of PSCI up to 3 years after stroke.

The FIELDS Instrument Suite for Solar Probe Plus: Measuring the Coronal Plasma and Magnetic Field, Plasma Waves and Turbulence, and Radio Signatures of Solar Transients

NASA's Solar Probe Plus (SPP) mission will make the first in situ measurements of the solar corona and the birthplace of the solar wind. The FIELDS instrument suite on SPP will make direct measurements of electric and magnetic fields, the properties of in situ plasma waves, electron density and temperature profiles, and interplanetary radio emissions, amongst other things. Here, we describe the scientific objectives targeted by the SPP/FIELDS instrument, the instrument design itself, and the instrument concept of operations and planned data products.

Cerebral small vessel disease, medial temporal lobe atrophy and cognitive status in patients with ischaemic stroke and transient ischaemic attack

BACKGROUND AND PURPOSE

Small vessel disease (SVD) and Alzheimer's disease (AD) are two common causes of cognitive impairment and dementia, traditionally considered as distinct processes. The relationship between radiological features suggestive of AD and SVD was explored, and the association of each of these features with cognitive status at 1 year was investigated in patients with stroke or transient ischaemic attack.

METHODS

Anonymized data were accessed from the Virtual International Stroke Trials Archive (VISTA). Medial temporal lobe atrophy (MTA; a marker of AD) and markers of SVD were rated using validated ordinal visual scales. Cognitive status was evaluated with the Mini Mental State Examination (MMSE) 1 year after the index stroke. Logistic regression models were used to investigate independent associations between (i) baseline SVD features and MTA and (ii) all baseline neuroimaging features and cognitive status 1 year post-stroke.

RESULTS

In all, 234 patients were included, mean (±SD) age 65.7 ± 13.1 years, 145 (62%) male. Moderate to severe MTA was present in 104 (44%) patients. SVD features were independently associated with MTA (P < 0.001). After adjusting for age, sex, disability after stroke, hypertension and diabetes mellitus, MTA was the only radiological feature independently associated with cognitive impairment, defined using thresholds of MMSE ≤ 26 (odds ratio 1.94; 95% confidence interval 1.28-2.94) and MMSE ≤ 23 (odds ratio 2.31; 95% confidence interval 1.48-3.62).

CONCLUSION

In patients with ischaemic cerebrovascular disease, SVD features are associated with MTA, which is a common finding in stroke survivors. SVD and AD type neurodegeneration coexist, but the AD marker MTA, rather than SVD markers, is associated with post-stroke cognitive impairment.

Prevalence and predictors of hospital prealerting in acute stroke: a mixed methods study

Background

Thrombolysis can significantly reduce the burden of stroke but the time window for safe and effective treatment is short. In patients travelling to hospital via ambulance, the sending of a ‘prealert’ message can significantly improve the timeliness of treatment.

Objective

Examine the prevalence of hospital prealerting, the extent to which prealert protocols are followed and what factors influence emergency medical services (EMS) staff's decision to send a prealert.

Methods

Cohort study of patients admitted to two acute stroke units in West Midlands (UK) hospitals using linked data from hospital and EMS records. A logistic regression model examined the association between prealert eligibility and whether a prealert message was sent. In semistructured interviews, EMS staff were asked about their experiences of patients with suspected stroke.

Results

Of the 539 patients eligible for this study, 271 (51%) were recruited. Of these, only 79 (29%) were eligible for prealerting according to criteria set out in local protocols but 143 (53%) were prealerted. Increasing number of Face, Arm, Speech Test symptoms (1 symptom, OR 6.14, 95% CI 2.06 to 18.30, p=0.001; 2 symptoms, OR 31.36, 95% CI 9.91 to 99.24, p<0.001; 3 symptoms, OR 75.84, 95% CI 24.68 to 233.03, p<0.001) and EMS contact within 5 h of symptom onset (OR 2.99, 95% CI 1.37 to 6.50 p=0.006) were key predictors of prealerting but eligibility for prealert as a whole was not (OR 1.92, 95% CI 0.85 to 4.34 p=0.12). In qualitative interviews, EMS staff displayed varying understanding of prealert protocols and described frustration when their interpretation of the prealert criteria was not shared by ED staff.

Conclusions

Up to half of the patients presenting with suspected stroke in this study were prealerted by EMS staff, regardless of eligibility, resulting in disagreements with ED staff during handover. Aligning the expectations of EMS and ED staff, perhaps through simplified prealert protocols, could be considered to facilitate more appropriate use of hospital prealerting in acute stroke.

Coupled plasma haemofiltration filtration in severe sepsis: systematic review and meta-analysis

INTRODUCTION

Coupled plasma filtration and adsorption (CPFA) has been used in the treatment of severe sepsis with the intention of removing the proinflammatory and anti-inflammatory mediators from the systemic circulation. It is believed that this interrupts and moderates the septic cascade, but there is uncertainty about the benefits of this therapy.

METHODS

A systematic review and meta-analysis were performed to estimate the effects of CPFA on mortality in severe sepsis. The Cochrane CENTRAL Register of Controlled Trials, CINAHL, EMBASE, MEDLINE-EBSCO-Host, MEDLINE and ProQuest, were searched from 1997 to 2013. Randomised controlled trials, prospective cohort studies and retrospective cohort studies were included using the Centre for Reviews and Dissemination (CRD) framework. Data were abstracted using standard pro forma, and studies independently reviewed by two authors to confirm inclusion criteria. Quality of studies and risk of bias were assessed using the Grading of Recommendations, Assessment, Development and Evaluation Working Group (GRADE) and Critical Appraisal Skills (CASP) criteria, respectively. Meta-analysis was performed using Review Manager (RevMan V.5.1) software. The primary outcome was 28-day mortality. Secondary outcomes were mediator adsorption (picograms/mL), mean arterial BP (mm Hg) and oxygenation ratio.

RESULTS

17 studies met the inclusion criteria (n=441 patients, 242 CPFA). 14 studies reported the primary outcome of 28-day mortality. There were 88 deaths in CPFA patients versus 118 in those receiving haemofiltration: OR 0.34 (95% CI 0.24 to 0.13). Point estimates of effect on the secondary outcomes of mean arterial pressure and oxygen ratio favoured CPFA. Studies were small and heterogenous.

CONCLUSIONS

Evidence for CPFA in severe sepsis is sparse, of poor quality and further research is required, however, this meta-analysis noted improvements in survival rates of those patients treated with CPFA.

Post-stroke cognitive decline: an update and perspectives for clinical research

The close relationship between stroke and dementia is an important health issue. Ischaemic stroke can facilitate the onset of vascular dementia as well as aggravate pre-existing cognitive decline. The onset of cognitive decline may become manifest immediately following the onset of ischaemic stroke, but often there is a delay in the development of cognitive decline after a stroke. This delay can be seen as a therapeutic time window allowing interventions to be applied to preserve cognition following stroke. Both neurodegenerative and vascular mechanisms are activated and probably result in overlapping processes within the neurovascular unit. This review focuses on the incidence and prevalence of cognitive decline following stroke, predisposing stroke aetiologies, pre-stroke decline, imaging factors and biomarkers. Outcomes are discussed in relation to timing of assessment and neuropsychological tests used for evaluation of cognitive decline in ischaemic stroke patients. Including such tests in routine evaluations of stroke patients after some weeks or months is recommended. Finally, an outlook on ongoing and planned intervention trials is added and some recommendations for future research are proposed.

The effect of organohalogen contaminants on western Steller sea lion survival and movement in the Russian Far East

The western stock of Steller sea lions (Eumetopias jubatus) have experienced dramatic declines since the 1960s, particularly in the western Alaskan and Asian portions, which have continued to decline or stabilized at low levels. Multiple causes for this decline have been proposed and may include anthropogenic contamination from organohalogen contaminants (OCs). These include polychlorinated biphenyls (PCBs) and dichlorodiphenyltrichloroethane (DDT), which have not been ruled out as a potential cause for the lack of recovery. The objective of this study was to determine the effects of OCs on survival and movement probabilities estimated in program MARK using resighting data collected from 2003 to 2009. PCBs and DDTs were measured in whole blood from 136 (74 males and 62 females) individually marked, free-ranging pups from four Russian Far East rookeries. The mean concentration of ∑PCB and ∑DDT was 4.25±5.12 and 3.22±4.28 ng g(-1) ww (n=136), respectively, and the average ∑PCB and ∑DDT concentration for those above the aggregate mean (n=44) was 9.25±6.55 and 7.65±5.21 ng g(-1) ww, and those below the aggregate mean (n=92) the concentration was 1.86±0.89 and 1.11±0.65 ng g(-1) ww, respectively. The lowest estimated probabilities of survival occurred in the first year, ranging from 38% to 74%, but increased for ages 1-9, ranging from 82% to 94%. The greatest movement occurred from Medny Island west toward the Kamchatka Peninsula (33%) and to Bering Island (18%), and low movement estimates for other natal rookeries was largely due to minimal resighting effort. The estimated probabilities of resighting varied by location (48%-87%), but had greater precision than survival or movement parameters. Survival and movement were most affected by age and location rather than OCs.

The analysis of in-air reverberation patterns from medical ultrasound transducers

National guidelines for routine ultrasound quality assurance include the measurement of transducer sensitivity using the in-air reverberation pattern generated from a transducer operating in air. The in-air reverberation method has been compared with other well-known measures of transducer sensitivity, such as the Sonora FirstCall probe tester (Sonora Medical Systems Inc, Longmont, CO, USA) and phantom-based images. There is good agreement between the in-air reverberation images and the Sonora FirstCall probe data for individual crystal sensitivity. However, the in-air reverberation approach is cheaper and easier to implement for linear and curvilinear transducers. The methods used for measuring the in-air reverberation pattern and the influence of scanner parameters such as gain and output power have been investigated. In general, reliance on a visual assessment of reverberation depth can lead to inconsistencies in the measurement of reverberation depth, when taken over a period of several months. The value of scanner parameters, in particular scanner gain, is also important when trying to measure changes in reverberation depth due to changes in transducer performance. A more accurate assessment of changes in transducer sensitivity, using the in-air reverberation method, is found by measuring the peak pixel grey scale values within a chosen reverberation band in the image. This quantitative approach can be taken a step further by assessing changes within the whole in-air reverberation pattern, by applying a two-dimensional cross correlation between two reverberation images to assess changes in transducer performance.

A direct method for computing extreme value (Gumbel) parameters for gapped biological sequence alignments

We develop a general method for computing extreme value distribution (Gumbel, 1958) parameters for gapped alignments. Our approach uses mixture distribution theory to obtain associated BLOSUM matrices for gapped alignments, which in turn are used for determining significance of gapped alignment scores for pairs of biological sequences. We compare our results with parameters already obtained in the literature.

Urease and Helicobacter spp. antigens in pulmonary granuloma

Pulmonary sarcoidosis, a human disease of unknown cause, has no animal model. Sarcoidosis patients have serum antibodies specific for Helicobacter pylori and its surface enzyme urease. H. pylori do not survive in the high-oxygen pulmonary atmosphere, but urease may access the lung by oesophageal reflux. A model was established in rats to study gastro-oesophageal reflux of urease into the airways. Pathology in tissues from human sarcoidosis patients was compared with that in the rat model. Changes observed in the rat model included prominent peribronchial lymphocytic infiltration, which is seen occasionally in human sarcoidosis. Granulomas, pathognomonic for human sarcoidosis, occurred occasionally in the lungs of rats given urease protein intratracheally, but were widespread when urease was coupled to microbeads and administered intravenously. Biomarkers associated with human sarcoidosis (interleukin1-β and platelet-activating factor) were up-regulated acutely in the rat model. Further investigations with this model may provide significant insights into the origin and pathogenesis of pulmonary diseases in man and other species that carry gastric Helicobacter spp. and its associated enzyme.

Exploring the parameter space of a rabbit ventricular action potential model to investigate the effect of variation on action potential and calcium transients

Computational models for cardiomyocyte action potentials (AP) often make use of a large parameter set. This parameter set can contain some elements that are fitted to experimental data independently of any other element, some elements that are derived concurrently with other elements to match experimental data, and some elements that are derived purely from phenomenological fitting to produce the desired AP output. Furthermore, models can make use of several different data sets, not always derived for the same conditions or even the same species. It is consequently uncertain whether the parameter set for a given model is physiologically accurate. Furthermore, it is only recently that the possibility of degeneracy in parameter values in producing a given simulation output has started to be addressed. In this study, we examine the effects of varying two parameters (the L-type calcium current (I(CaL)) and the delayed rectifier potassium current (I(Ks))) in a computational model of a rabbit ventricular cardiomyocyte AP on both the membrane potential (V(m)) and calcium (Ca(2+)) transient. It will subsequently be determined if there is degeneracy in this model to these parameter values, which will have important implications on the stability of these models to cell-to-cell parameter variation, and also whether the current methodology for generating parameter values is flawed. The accuracy of AP duration (APD) as an indicator of AP shape will also be assessed.

Cardiac valve annulus manual segmentation using computer assisted visual feedback in three-dimensional image data

Annulus manual segmentation is an important tool for the study of valve anatomy and physiology, for the four main valves of the heart (mitral, tricuspid, aortic and pulmonary). In this paper we review two traditional manual segmentation approaches: slice-by-slice and interpolating a sparse set of landmarks with a spline curve. We propose a new Spline Tool for the open source software platform Seg3D, that is fast and improves spatial coherence by providing visual feedback of the segmentation in real time. The Spline Tool was tested successfully on 14 rat hearts, on all four valves.

Targeted melanoma imaging and therapy with radiolabeled alpha-melanocyte stimulating hormone peptide analogues

Radiolabeled alpha-melanocyte stimulating hormone (a-MSH) analogues have been used to define the expression, affinity and function of the melanocortin-1 receptor (MC1-R). The MC1-R is one of a family of five G-protein linker receptors, which is primarily involved in regulation of skin pigmentation. Over-expression of the MC1-R on melanoma tumor cells has made it an attractive target for the development of a-MSH peptide based imaging and therapeutic agents. Initially, the native a-MSH peptide was radiolabeled directly, but it suffered from low specific activity and poor stability. The addition of non-natural amino acids yielded a-MSH analogues with greater MC-1R affinity and stability. Furthermore, peptide cyclization via disulfide and lactam bond formation as well as site-specific metal coordination resulted in additional gains in receptor affinity and peptide stability in vitro and in vivo. Radiochemical stability of the a-MSH analogues was improved through the conjugation of metal chelators to the peptide's N-terminus or lysine residues for radionuclide coordination. In vitro cell binding studies demonstrated that the radiolabeled a-MSH analogues had low to subnanomolar affinities for the MC1-R. Biodistribution and imaging studies in the B16 mouse melanoma modeled showed rapid tumor uptake of the radiolabeled peptides, with the cyclic peptides demonstrating prolonged tumor retention. Cyclic a-MSH analogues labeled with beta and alpha emitting radionuclides demonstrated melanoma therapeutic efficacy in the B16 melanoma mouse model. Strong pre-clinical imaging and therapy data highlight the clinical potential use of radiolabeled a-MSH peptides for melanoma imaging and treatment of disseminated disease.

Biochemical and histological effects of exendin-4 (exenatide) on the rat pancreas

AIMS/HYPOTHESIS

Exendin-4 is a 39 amino acid agonist of the glucagon-like peptide receptor and has been approved for treatment of type 2 diabetes. Many reports describe an increased incidence of acute pancreatitis in humans treated with exendin-4 (exenatide). Previous studies have evaluated the effect of exendin-4 on beta cells and beta cell function. We evaluated the histological and biochemical effects of exendin-4 on the pancreas in rats.

METHODS

We studied 20 Sprague-Dawley male rats, ten of which were treated with exendin-4 and ten of which were used as controls. The study period was 75 days. Serum and pancreatic tissue were removed for biochemical and histological study. Blood glucose, amylase, lipase, insulin and adipocytokines were compared between the two groups.

RESULTS

Animals treated with exendin-4 had more pancreatic acinar inflammation, more pyknotic nuclei and weighed significantly less than control rats. They also had higher serum lipase than control animals. Exendin-4 treatment was associated with lower insulin and leptin levels as well as lower HOMA values than in the untreated control group.

CONCLUSIONS/INTERPRETATION

Although the use of exendin-4 in rats is associated with decreased weight gain, lower insulin resistance and lower leptin levels than in control animals, extended use of exendin-4 in rats leads to pancreatic acinar inflammation and pyknosis. This raises important concerns about the likelihood of inducing acute pancreatitis in humans receiving incretin mimetic therapy.

Rapid Formation of Supermassive Black Hole Binaries in Galaxy Mergers with Gas

Supermassive black holes (SMBHs) are a ubiquitous component of the nuclei of galaxies. It is normally assumed that after the merger of two massive galaxies, a SMBH binary will form, shrink because of stellar or gas dynamical processes, and ultimately coalesce by emitting a burst of gravitational waves. However, so far it has not been possible to show how two SMBHs bind during a galaxy merger with gas because of the difficulty of modeling a wide range of spatial scales. Here we report hydrodynamical simulations that track the formation of a SMBH binary down to scales of a few light years after the collision between two spiral galaxies. A massive, turbulent, nuclear gaseous disk arises as a result of the galaxy merger. The black holes form an eccentric binary in the disk in less than 1 million years as a result of the gravitational drag from the gas rather than from the stars.

Application of pulsed-field gel electrophoresis to characterise and trace the prevalence of Enterobacter sakazakii in an infant formula processing facility

Enterobacter sakazakii (E. sakazakii) contamination of powdered infant formula (PIF) and its processing environment was monitored between April 2005 and March 2006. The purpose of the monitoring programme was to locate points of contamination, investigate clonal persistence, and identify possible dissemination routes along the processing chain. A total of 80 E. sakazakii isolates were recovered from the manufacturing facility. The overall frequency of isolation of E. sakazakii in intermediate and final product was 2.5%, while specific locations in the processing environment were contaminated at frequencies up to 31%. All E. sakazakii isolates were characterised by pulsed-field gel electrophoresis (PFGE). XbaI macrorestriction digests yielded 19 unique pulse-types that could be grouped into 6 clusters of between 5 and 32 isolates. The formation of large clusters was consistent with the presence of a number of clones in the manufacturing environment. While the majority of isolates were of environmental origin (72.5%), no cluster was confined to one specific location and indistinguishable PFGE profiles were generated from isolates cultured from the manufacturing environment, sampling points along the processing chain and from intermediate and final product. These findings suggest that the manufacturing environment serves as a key route for sporadic contamination of PIF. These data will support the development of efficient intervention measures contributing to the reduction of E. sakazakii in the PIF processing chain.

Enterobacter sakazakii an emerging bacterial pathogen with implications for infant health

Enterobacter sakazakii (E. sakazakii) is an opportunistic pathogen and the aetiological agent in rare but life-threatening cases of meningitis, necrotizing enterocolitis, and sepsis in infants. Among infants, those at greatest risk are neonates (<28 days), particularly those born prematurely or of low birth weight (<2500 g). Consumption of contaminated powdered infant formula (PIF) has been epidemiologically linked with cases of infection. Contamination can occur during the manufacturing process or during postmanufacture reconstitution of formula. Development of rapid, sensitive and specific detection methods will facilitate manufacturers efforts to reduce the occurrence of E. sakazakii in the final powdered product. Furthermore, since PIF is not a sterile product, proper precautions should be taken during handling and reconstitution of formula prior to feeding in order to prevent contamination and proliferation of the bacterium.

Meanaging Knowledge for the emergency care of heart attack patients: Paramedics and thrombolytic treatment

The objective of this paper is to examine the Knowledge Management(KM) paradigm in the context of UK paramedics' assessment and treatment of patients with suspected acute myocardial infarction (MI) or ;heart attack' We outline the role of thrombolytic therapy and other aspects of emergency cardiac care and discuss how contemporary KM tools and techniques can be used to support the development and retention of key clinical skills and knowledge in this emerging field of parcice.