Quantification of hardware effects of an on-line Dual Energy X-ray Absorptiometry scanner when predicting lamb carcass composition.

An on-line Dual Energy X-ray Absorptiometry (DXA) scanner's tissue composition prediction precision and accuracy was tested across the entire height of the unit's detector, and the hardware was assessed for robustness by measuring X-ray photon intensity throughout production days. There was good precision when predicting the tissue composition of 5 different lamb fat and lean muscle mixtures across 3 different thicknesses (R2 = 0.93 to 0.98, RMSE = 3.18% to 5.83%), however was less precise at the greatest thickness of 200 mm (R2 = 0.59, RMSE = 11.4%). There was no significant difference in the prediction of tissue composition at 8 of the 9 detector positions, however the position at the perpendicular of the X-ray photon beam was significantly different, with a fat prediction error of -4%, although no lamb carcass is detected in this position during normal production. A significant upwards drift in X-ray photon intensity was found over the course of production, especially immediately after restarting the DXA scanner following a period of inactivity. This upwards drift may affect tissue composition predictions over the span of a production day if uncorrected.

Dual energy X-ray absorptiometry predicts lamb carcass composition at abattoir chain speed with high repeatability across varying processing factors.

An on-line Dual Energy X-ray Absorptiometry (DXA) scanner was used in an Australian abattoir to predict computed tomography (CT) determined composition % of fat, lean muscle and bone in lamb carcasses at chain speed. This study assessed the effect of spray-chilling on these estimates, as well as their repeatability over a 10-min period, and over a 72 h period. There was no prediction bias between the 15 spray-chilled and 15 non-spray-chilled carcasses. When repeat DEXA scans were undertaken across a 10-min period, there was a high level of repeatability for the prediction of CT Fat %. When repeat scans were conducted at 6 time points across a 72 h period the precision of the DXA prediction of CT Fat % of 30 carcasses remained high (R2 = 0.94, RMSEP = 1.20%), although small biases existed between time points (P < 0.01). These biases were minimised when the DXA scanner had been operational prior to experimentation, suggesting a 'warm-up' effect.

Preliminary Findings on a Novel Behavioural Approach for the Assessment of Pain and Analgesia in Lambs Subject to Routine Husbandry Procedures.

The identification and assessment of pain in sheep under field conditions are important, but, due to their stoic nature, are fraught with many challenges. In Australia, various husbandry procedures that are documented to cause pain are routinely performed at lamb marking, including ear tagging, castration, mulesing, and tail docking. This study evaluated the validity of a novel methodology to assess pain in lambs: qualitative behavioural assessment (QBA) was used to compare the behavioural expression of control lambs (CONTROL) with that of lambs subject to these procedures that received either a saline placebo 15 min before procedures (PLACEBO), or were administered meloxicam 15 min before procedures in addition to the standard analgesic Tri-Solfen at the time of procedures, as per the manufacturer's recommendations (ANALGESIC TREATMENT; AT). In terms of behavioural expression, it was expected that: CONTROL ≠ PLACEBO, AT = CONTROL, and PLACEBO ≠ AT. Video footage of the 6-8-week-old lambs (n = 10 for each treatment) was captured approximately 1.5 h postprocedure and was presented, in a random order, to 19 observers for assessment using the Free-Choice Profiling (FCP) approach to QBA. There was significant consensus (p < 0.001) among the observers in their assessment of the lambs, with two main dimensions of behavioural expression explaining 69.2% of the variation. As expected, observers perceived differences in the demeanour of lambs in the first dimension, scoring all lambs subject to the routine husbandry procedures as significantly more 'dull' and 'uneasy' compared to the control lambs (p < 0.05). Contrary to expectations, the results also suggested that analgesic treatment did not provide relief at the time of observation. Further investigations to validate the relationship between behavioural expression scores and pain are necessary, but these results suggest that painful husbandry procedures alter the behavioural expression of lambs and these differences can be captured using QBA methodology.

Lamb Age has Little Impact on Eating Quality.

There is an industry wide perception that new season lamb has better eating quality than old season lamb. This study aims to identify differences in consumer eating quality scores between two age classes in lamb. Consumer eating quality scores from eight cuts across the carcass were evaluated from new season (NS; n = 120; average age = 240 days) and old season lambs (OS; n = 121; average age = 328 days), sourced from four different flocks. Cuts were grilled (loin, topside, outside, knuckle and rump) or roasted (leg, shoulder, rack) and scored by untrained consumers for tenderness, juiciness, liking of flavour and overall liking. There was no difference in eating quality scores between the two age classes for the loin, leg, shoulder and rack. This was similarly shown in the topside with the exception of juiciness scores where NS lambs were higher than OS lambs. There was also a lack of age difference in the outside with the exception of flock 3 where NS lambs scored higher than OS lambs for all sensory traits. Across all sensory traits, OS lambs received on average 2.8 scores lower for the knuckle and 3.1 scores lower for the rump compared to NS lambs. These results show little difference in eating quality between NS and OS lamb, and highlight the potential to develop high quality OS or "autumn lamb" products, with a similar premium price at retail as NS lambs.

Remote Identification of Sheep with Flystrike Using Behavioural Observations.

Flystrike is a major problem affecting sheep in Australia. Identification of 'flystruck' individuals is crucial for treatment; but requires labour-intensive physical examination. As the industry moves toward more low-input systems; there is a need for remote methods to identify flystruck individuals. The aim of this study was to investigate the behaviour of sheep with breech flystrike within a paddock setting. Video footage of sixteen Merino sheep; eight later confirmed with flystrike and eight without; was collected as they moved freely within the paddock with conspecifics. Quantitative behavioural measurements and a qualitative behavioural assessment (QBA) were conducted and compared to their breech conditions (i.e., faecal/urine staining; flystrike severity). Both qualitative and quantitative assessments indicated behavioural differences between flystruck and non-flystruck animals. Flystruck sheep had a behavioural profile characterised by restless behaviour; abnormal postures and reduced grazing time (p < 0.05). Furthermore; flystruck sheep were scored to have a more 'exhausted/irritated' demeanour using QBA (p < 0.05). The behavioural responses also corresponded to the flystrike severity scores and condition of the breech area. We conclude that remotely assessed behaviour of flystruck sheep diverges markedly from non-flystruck sheep; and thus could be a low-input method for identifying and treating affected animals.

Dual-energy X-ray absorptiometry scans accurately predict differing body fat content in live sheep.

BACKGROUND: There is considerable interest in implementing mobile scanning technology for on-farm body composition analysis on live animals. These experiments evaluated the use of dual energy X-ray absorptiometry (DXA) as an accurate method of total body fat measurement in live sheep. RESULTS: In Exp. 1, visceral and whole body fat analysis was undertaken in sheep with body condition scores (BCS) in the range 2 to 3.25 (scale 1: thin to 5: fat). The relationship of BCS was moderately correlated with visceral fat depot mass (r = 0.59, P < 0.01, n = 24) and whole body fat (r = 0.70, P < 0.001, n = 24). In Exp. 2, sheep with BCS in the range 2.25 to 3.75 were blood sampled to analyse circulating leptin concentrations, and were DXA scanned immediately post mortem for total body fat. Plasma leptin concentrations had low correlations with BCS (r = 0.50, P < 0.05, n = 17) and DXA body fat (r = 0.42, P < 0.05, n = 17), and no correlation with chemical body fat (r = 0.17, P > 0.05, n = 9). There was a moderate correlation between DXA body fat and BCS (r = 0.70, P < 0.01, n = 17), and DXA body fat was highly correlated with chemical body fat (r = 0.81, P < 0.001, n = 9). In Exp. 3, a series of five DXA scans, at 8-week intervals, was performed on growing sheep over a 32-week period. The average BCS ranged from 2.39 ± 0.07 (S.E.M.) to 3.05 ± 0.11 and the DXA body fat (%) ranged from 16.8 ± 0.8 to 24.2 ± 1.2. There was a moderate correlation between DXA body fat and BCS over the 32 weeks (r = 0.61, P < 0.001, n = 24). CONCLUSIONS: Overall, these experiments indicated that there was good agreement between BCS, DXA and chemical analysis for measuring total body fat in sheep, and that DXA scanning is a valid method for longitudinal measurement of total body fat in live sheep.

Cryptosporidium infection is associated with reduced growth and diarrhoea in goats beyond weaning.

Cryptosporidium and Giardia are common parasites of ruminant livestock worldwide. These parasites are associated with diarrhoea outbreaks in young goats (pre-weaning), but the impacts on health and productivity for older goats (post-weaning) are not well understood. Here we show Cryptosporidium faecal shedding is associated with reduced growth and diarrhoea in goats aged approximately 9-15 months. Goats were sampled four times at one-month intervals. Faecal shedding for a range of pathogens were determined using quantitative PCR and sequencing (Cryptosporidium, Giardia, Eimeria, Salmonella, Campylobacter), and microscopy (trichostrongylid nematode worm egg count and Entamoeba). Cryptosporidium faecal shedding was associated with 1.5 kg lower growth for the one-month period following sampling. Specifically, C. xiaoi was associated with 1.9 kg lower growth in the following month. This is the first report of production impacts associated with C. xiaoi in ruminants older than 3 months of age. Cryptosporidium shedding was associated with an over 4-fold increase in risk of diarrhoea, with C. parvum associated with 10-fold and C. ubiquitum associated with 16-fold increase in risk of diarrhoea. Notably, C. xiaoi shedding was not associated with increased risk of diarrhoea. Giardia shedding was associated with looser faecal consistency, but not diarrhoea. Higher Eimeria oocyst counts were weakly associated with lower live weight, poorer body condition and looser faecal consistency. Shedding of other enteric pathogens were not associated with impacts on live weight, growth or diarrhoea risk. This study challenges the two notions that Cryptosporidium infections only impact health and productivity of goats during the pre-weaning period, and that Cryptosporidium (and specifically C. xiaoi) infections in the absence of diarrhoea are asymptomatic. Recognising the potential for impacts of Cryptosporidium infection on growth rates in the absence of diarrhoea will support improved design for experiments testing impacts of Cryptosporidium on ruminant health and production. Improved understanding of the role of protozoan infections on animal health has implications for the management of goats in order to reduce adverse impacts on farm profitability, animal welfare and public health risk.

Using simulation to support doctors in difficulty.

BACKGROUND: A small percentage of medical trainees will have performance concerns identified within their clinical practice. These trainees require specific interventions to address these concerns. The Postgraduate Ward Simulation Exercise (PgWSE) was developed as a joint collaboration between the University of Dundee and NHS Education for Scotland (NES). CONTEXT: The PgWSE takes around 90 minutes to complete. It allows assessors to directly observe the performance of trainees within a simulated ward environment. Trainees are assessed individually on their ability to prioritise competing demands, work as part of a team and make safe informed clinical decisions. INNOVATION: The PgWSE is the first specific national intervention to support the assessment and remediation of trainee doctors in difficulty. Nine PgWSE scenarios have been developed to reflect clinical practice: three in general surgery, four in general medicine and two in medicine for the elderly. To enhance realism, simulated patients (SPs) are recruited and trained for each exercise. Standardised assessment tools were developed and validated for assessors to make individual and consensus judgements regarding a trainee's performance. Self-assessment of performance is used to disengage trainees from the simulated activity and to prepare them for constructive feedback. IMPLICATIONS: The PgWSE has been shown to be a valuable tool for the management of trainee doctors in difficulty in Scotland. Although the PgWSE is time and resource intensive, it has been shown to have a positive impact on the remediation of trainees and in the provision of objective, detailed and comprehensive feedback to the referring deanery. Within NES there are four geographical centres led by a postgraduate dean with responsibility for supervision of postgraduate medical education.

Supporting trainees in difficulty: a new approach for Scotland.

National Health Service (NHS) Education for Scotland (NES) works with NHS and University employers, through the four Postgraduate Deaneries to provide education and training for medical trainees from graduation to completion of specialist and general practice training. Most trainees make good progress through the relevant curriculum supported by a managed system of supervision with regular appraisal and feedback. Similarly most trainees demonstrate their progression to Certificate of Completion of Training through the assessment process that is defined in each specialty curriculum. However a small number of trainees each year will experience difficulties sufficient to impact on their progress and when this occurs, a clear plan of investigation, support and management is required. These activities now have to be robust, and are subject to quality management locally and also external scrutiny by Postgraduate Medical Education and Training Board. Therefore, there is a need for the management process to be clear and consistent, and easily accessible to both trainees and their consultant supervisors. NES has introduced a new infrastructure for Scotland which is described in this paper. The paper also discusses training of educational supervisors, best use of national training and remediation resources and how a national advisory group might contribute.

Irregular respiration as a marker of wakefulness during titration of CPAP.

STUDY OBJECTIVES: Regularity of respiration is characteristic of stable sleep without sleep disordered breathing. Appearance of respiratory irregularity may indicate onset of wakefulness. The present study examines whether one can detect transitions from sleep to wakefulness using only the CPAP flow signal and automate this recognition. DESIGN: Prospective study with blinded analysis SETTING: Sleep disorder center, academic institution. PARTICIPANTS: 74 subjects with obstructive sleep apnealhypopnea syndrome (OSAHS) INTERVENTIONS: n/a. MEASUREMENTS AND RESULTS: 74 CPAP titration polysomnograms in patients with OSAHS were examined. First we visually identified characteristic patterns of ventilatory irregularity on the airflow signal and tested their relation to conventional detection of EEG defined wake or arousal. To automate recognition of sleep-wake transitions we then developed an artificial neural network (ANN) whose inputs were parameters derived exclusively from the airflow signal. This ANN was trained to identify the visually detected ventilatory irregularities. Finally, we prospectively determined the accuracy of the ANN detection of wake or arousal against EEG sleep/wake transitions. A visually identified irregular respiratory pattern (IrREG) was highly predictive of appearance of EEG wakefulness (Positive Predictive Value [PPV] = 0.89 to 0.98 across subjects). Furthermore, we were able to automate identification of this irregularity with an ANN which was highly predictive for wakefulness by EEG (PPV 0.66 to 0.86). CONCLUSIONS: Despite not detecting all wakefulness, the high positive predictive value suggests that analysis of the respiration signal alone may be a useful indicator of CNS state with potential utility in the control of CPAP in OSAHS. The present study demonstrates the feasibility of automating the detection of IrREG.

Neurocognitive late effects of chemotherapy in children: the past 10 years of research on brain structure and function.

Advances in the treatment of childhood cancers have greatly improved survivorship. Success has not come without cost, however, as survivors are at risk for late effects of treatment, including neurocognitive late effects (e.g., difficulties with thinking and reasoning). In the advent of chemotherapy-only protocols, researchers are examining neurocognitive sequelae of these agents to understand the specific role of chemotherapy in neurocognitive changes and the mechanism through which these occur. In this review, we examine the state of the literature on neurocognitive late effects after chemotherapy and their proposed neural mechanisms.

Diffusion tensor imaging identifies deficits in white matter microstructure in subjects with type 1 diabetes that correlate with reduced neurocognitive function.

OBJECTIVE: Long-standing type 1 diabetes is associated with deficits on neurocognitive testing that suggest central white matter dysfunction. This study investigated whether diffusion tensor imaging (DTI), a type of magnetic resonance imaging that measures white matter integrity quantitatively, could identify white matter microstructural deficits in patients with long-standing type 1 diabetes and whether these differences would be associated with deficits found by neurocognitive tests. RESEARCH DESIGN AND METHODS: Twenty-five subjects with type 1 diabetes for at least 15 years and 25 age- and sex-matched control subjects completed DTI on a 3.0 Tesla scanner and a battery of neurocognitive tests. Fractional anisotropy was calculated for the major white matter tracts of the brain. RESULTS: Diabetic subjects had significantly lower mean fractional anisotropy than control subjects in the posterior corona radiata and the optic radiation (P < 0.002). In type 1 diabetic subjects, reduced fractional anisotropy correlated with poorer performance on the copy portion of the Rey-Osterreith Complex Figure Drawing Test and the Grooved Peg Board Test, both of which are believed to assess white matter function. Reduced fractional anisotropy also correlated with duration of diabetes and increased A1C. A history of severe hypoglycemia did not correlate with fractional anisotropy. CONCLUSIONS: DTI can detect white matter microstructural deficits in subjects with long-standing type 1 diabetes. These deficits correlate with poorer performance on selected neurocognitive tests of white matter function.

White versus gray matter function as seen on neuropsychological testing following bone marrow transplant for acute leukemia in childhood.

Current theory suggests that neurocognitive late effects of treatments for childhood cancer such as difficulties with attention, processing speed and visual-motor ability are the result of white matter damage. Neuroimaging studies have produced a variety of white matter findings. However, although white matter is thought to be differentially affected, previous studies have not demonstrated a discrepancy between white and gray matter function. The present study included 36 children treated for childhood leukemia with hematopoietic stem cell transplant (HCT). Their performance on neurocognitive measures traditionally thought to measure white matter was compared to performance on measures thought to measure gray matter function. Composite white and gray matter standard scores were created based on neuropsychological measures that individuals with known white or gray matter damage perform poorly. As predicted, composite white matter scores (mean = 98.1) were significantly lower (t = 2.26, p = 0.03) than composite gray matter scores (mean = 102.5). Additionally, as gray matter performance increased, the difference between gray and white matter scores increased (R = 0.353, p = 0.035). Overall, the results of this study support the current theory that white matter damage is responsible for the more subtle neurocognitive late effects resulting from treatment for childhood leukemia.

Sequence and priming in 15 month-olds' reactions to brief arm restraint: evidence for a hierarchy of anger responses.

Brief, gentle arm restraint is widely used in experimental studies of children's anger, but the pattern of responses generated by such restraint has been incompletely described. We now describe a hierarchy of responses within trials as well as an escalation across trials that have both methodological and theoretical significance. Mothers of 87 15-month olds prevented them from playing with a toy by restraining their arms on two consecutive 30 sec trials. Physical struggling was the first and most frequent response; children who struggled were significantly more likely to vocalize, and those who vocalized were significantly more likely to show facial expressions of anger. The children's responses became more probable, rapid, and intense during Trial 2 restraint. Overall, the hierarchy was orderly enough to meet criteria for Guttman scalability. The particular sequence observed suggests situational, as opposed to bio-energetic, ordering of responses. Methodologically, the two trial paradigm is a simple, ecologically valid model for studying anger escalation that parallels the "attack priming" of aggression in other species. The magnitude and persistence of anger priming may provide novel measures of anger regulation. Theoretically, the existence of an orderly response hierarchy is consistent with previous observations suggesting that, within a situational context, the sequential appearance of specific behaviors may indicate progressive increases in anger intensity.

Long-term follow-up of children who underwent hematopoeitic cell transplant (HCT) for AML or ALL at less than 3 years of age.

BACKGROUND: Hematopoeitic cell transplantation (HCT) in childhood has been associated with late complications including endocrine, neurocognitive, and cardiopulmonary abnormalities. Little is known about the complications of transplantation in infants. PROCEDURE: Eligible subjects underwent HCT for acute lymphoblastic leukemia (ALL) or acute myelogenous leukemia (AML) at less than 3 years of age. Seventeen out of 33 eligible patients were evaluated, transplanted between 1981-2000. Eleven patients had AML, 11 were female. Preparative regimen included total body irradiation (TBI) for eleven. Age at HCT ranged from 0.58 to 2.97 years, and survival 3.25 to 22.33 years. Patients underwent physical and laboratory evaluation, dual-energy X-ray absorptiometry (DXA) scan, bone age X-ray, neuropsychological, and quality of life (QOL) evaluation. RESULTS: Identified abnormalities included: growth hormone deficiency (59%), hypothyroidism (35%), osteochondromas (24%), decreased bone mineral density (24%), and dyslipidemias (59%). Two patients developed a second malignancy. Neuropsychological testing revealed average intelligence quotient (IQ) with attention deficits and other weaknesses for most patients. There were no overall differences between QOL in these children when compared to population norms. CONCLUSIONS: Of the survivors evaluated, typical late effects seen after radiation exposure are common, yet most subjects were doing well without major ongoing medical issues. Dyslipidemias affect more than half of patients and may be associated with metabolic syndrome, placing patients at increased risk for early cardiovascular disease. Even in this group of patients where the majority was exposed to TBI at a very young age, most are functioning at an average or above-average level.

On-the-job assessment of practical skills performance: experiences from a feasibility study.

A pilot exercise throughout one deanery during a whole training year has shown that the on-the-job assessment of practical skills is both feasible and acceptable to the wider health-care team. There was, however, a lack of exposure by trainees to a small number of specific procedural skills.

Can a ward simulation exercise achieve the realism that reflects the complexity of everyday practice junior doctors encounter?

Recent changes in medical education have resulted in an increased focus on patient safety. It is vital that new doctors can recognize and manage acutely-ill patients, as well as work safely and effectively as a member of a multi-professional team. A ward simulation exercise has been developed to provide a safe, but authentic setting to support junior doctors with further practice and feedback. In developing such an exercise realism is important in recreating the complex climate in which the junior doctor has to function as part of the healthcare team in the hospital ward. This paper shares the design methodology of a ward simulation exercise and the views on its authenticity from both the junior doctors and the observers.

PRHO views on the usefulness of a pilot ward simulation exercise.

There are concerns that pre-registration house officers (PRHOs) lack the expertise to initially manage acutely-ill patients. Simulation can support them in this role by providing a safe yet authentic setting. This paper shares PRHOs' views of a ward simulation exercise. The positive feedback has resulted in further development of the exercise to support PRHOs who have given cause for concern in their practice.

Synthesis of novel DNA cross-linking antitumour agents based on polyazamacrocycles.

We are seeking to develop more effective alkylating agents as antitumour agents. In previous work conformationally restricted nitrogen mustards were synthesised containing piperidine or pyrrolidine rings. The free bases were designed to be bifunctional alkylating agents via aziridinium ion formation and the effects of varying the distances between the two alkylating sites were studied. Some efficient cross-linkers of naked DNA were prepared but few of these compounds exhibited significant cytotoxicity in human tumour cells in vitro. We have extended this work by making tri- and tetra-azamacrocyclic compounds containing two to four potential alkylating sites. Most of these compounds were powerful DNA alkylating agents and showed cytotoxicity (IC(50) values 6-100microM) comparable with chlorambucil (45microM) and melphalan (8.5microM). In particular the cyclen derivative 2a was more than 10(4) times more effective at cross-linking DNA (2a XL(50)<<10nM) than chlorambucil (XL(50) 100microM), and showed significant cytotoxicity in human tumour cells in vitro.