PrP aggregation can be seeded by pre-formed recombinant PrP amyloid fibrils without the replication of infectious prions

Mammalian prions are unusual infectious agents, as they are thought to consist solely of aggregates of misfolded prion protein (PrP). Generation of synthetic prions, composed of recombinant PrP (recPrP) refolded into fibrils, has been utilised to address whether PrP aggregates are, indeed, infectious prions. In several reports, neurological disease similar to transmissible spongiform encephalopathy (TSE) has been described following inoculation and passage of various forms of fibrils in transgenic mice and hamsters. However, in studies described here, we show that inoculation of recPrP fibrils does not cause TSE disease, but, instead, seeds the formation of PrP amyloid plaques in PrP-P101L knock-in transgenic mice (101LL). Importantly, both WT-recPrP fibrils and 101L-recPrP fibrils can seed plaque formation, indicating that the fibrillar conformation, and not the primary sequence of PrP in the inoculum, is important in initiating seeding. No replication of infectious prions or TSE disease was observed following both primary inoculation and subsequent subpassage. These data, therefore, argue against recPrP fibrils being infectious prions and, instead, indicate that these pre-formed seeds are acting to accelerate the formation of PrP amyloid plaques in 101LL Tg mice. In addition, these data reproduce a phenotype which was previously observed in 101LL mice following inoculation with brain extract containing in vivo-generated PrP amyloid fibrils, which has not been shown for other synthetic prion models. These data are reminiscent of the "prion-like" spread of aggregated forms of the beta-amyloid peptide (Aβ), α-synuclein and tau observed following inoculation of transgenic mice with pre-formed seeds of each misfolded protein. Hence, even when the protein is PrP, misfolding and aggregation do not reproduce the full clinicopathological phenotype of disease. The initiation and spread of protein aggregation in transgenic mouse lines following inoculation with pre-formed fibrils may, therefore, more closely resemble a seeded proteinopathy than an infectious TSE disease.

Using a blended e-learning model to provide accessible infection prevention and control training for NHS staff: The NHSU/TVU/Intuition approach

ver the past two decades, healthcare-associated infections (HCAI) have emerged as a significant threat to high quality health care. The technological advances made in the treatment of many diseases and disorders are being undermined by the transmission of infections within healthcare settings, especially the emergence of antimicrobial resistant strains of Staphylococcus aureus and enterococci that are now endemic in some healthcare environments. The financial and personal costs of HCAI in terms of the economic consequences to the National Health Service (NHS) and the physical, social and psychological costs to patients and their relatives have increased both government and public awareness of the risks associated with healthcare interventions and in particular the consequences of HCAI.

The risk of acquiring HCAI continues to attract intense media interest. Reports of dirty hospitals and stories of healthcare workers failing to observe even the most rudimentary hygiene and other infection prevention and control measures are causing profound anxiety among service users. The public is fast losing confidence in the NHS to safely care for them and this dissatisfaction has propelled HCAI to the top of an increasingly urgent political healthcare agenda.

The Department of Health (DH) has focused a number of initiatives on combating HCAI, including the development of national evidence-based infection prevention and control guidelines for acute and primary care settings (Pratt et al, 2001; Pellowe et al, 2003), a research programme to identify a range of effective strategies for combating antimicrobial resistance and more recently setting out a strategy for reducing HCAI and improving environmental hygiene in healthcare settings (DH, 2002; DH, 2004). DH strategy emphasises the importance of ensuring that infection prevention and control training is included in the induction programme for all NHS staff, both clinical and nonclinical, including agency and locum staff, and that this training becomes part of their continuing personal development plans.

Professor Christine Beasley, the chief nursing officer at the DH has since taken responsibility for actualising many aspects of this strategy, especially ensuring that the required training is made available for all 1.3 million NHS staff by the end of 2005. Providing that training became the responsibility of the NHS University (NHSU), which commissioned the Richard Wells Research Centre at Thames Valley University London (TVU) along with their Dublin-based educational development partner, Intuition Publishing Ltd, to develop an appropriate and accessible state-of-the-art blended e-learning training programme.

In this article, we describe how we designed and structured the programme so that it can be used as an essential tool in orientation/induction, staff development and in-service education programmes for all NHS staff.

The 'S' test - a preliminary study of an instrument for selecting the most appropriate mobility aid

Objective: To develop and evaluate a qualitative and quantitative instrument for selecting the ideal mobility aid for those with mobility disorders.

Setting: A district general hospital-based geriatric unit.

Subjects: Elderly inpatients and outpatients with mobility disorders.

Interventions: Structured assessments with different mobility aids to select the most suitable.

Outcome measures: Safety, stance, stability, step/stride pattern and speed were considered.

Results: The 'S' test successfully selected an aid for all 49 subjects. For most this aid offered marked improvement in qualitative and quantitative aspects of gait when compared with the subject's usual aid.

Conclusions: The 'S' test is an effective tool for selecting mobility aids within an institutional setting.

Quantitative imaging of tissue sections using infrared scanning technology

Quantification of immunohistochemically (IHC) labelled tissue sections typically yields semi‐quantitative results. Visualising infrared (IR) ‘tags’, with an appropriate scanner, provides an alternative system where the linear nature of the IR fluorophore emittance enables realistic quantitative fluorescence IHC (QFIHC). Importantly, this new technology enables entire tissue sections to be scanned, allowing accurate area and protein abundance measurements to be calculated from rapidly acquired images. Here, some of the potential benefits of using IR‐based tissue imaging are examined, and the following are demonstrated. Firstly, image capture and analysis using IR‐based scanning technology yields comparable area‐based quantification to those obtained from a modern high‐resolution digital slide scanner. Secondly, IR‐based dual target visualisation and expression‐based quantification is rapid and simple. Thirdly, IR‐based relative protein abundance QIHC measurements are an accurate reflection of tissue sample protein abundance, as demonstrated by comparison with quantitative fluorescent Western blotting data. In summary, it is proposed that IR‐based QFIHC provides an alternative method of rapid whole‐tissue section low‐resolution imaging for the production of reliable and accurate quantitative data.

Use of the King-Devick test for sideline concussion screening in junior rugby league

AIM

To determine whether the King-Devick (K-D) test used as a sideline test in junior rugby league players over 12 matches in a domestic competition season could identify witnessed and incidentally identified episodes of concussion.

METHODS

A prospective observational cohort study of a club level junior rugby league team (n=19) during the 2014 New Zealand competition season involved every player completing two pre-competition season baseline trials of the K-D test. Players removed from match participation, or who reported any signs or symptoms of concussion were assessed on the sideline with the K-D test and referred for further medical assessment. Players with a pre- to post-match K-D test difference >3s were referred for physician evaluation.

RESULTS

The baseline test-retest reliability of the K-D test was high (rs=0.86; p<0.0001). Seven concussions were medically identified in six players who recorded pre- to post-match K-D test times greater than 3s (mean change of 7.4s). Post-season testing of players demonstrated improvement of K-D time scores consistent with learning effects of using the K-D test (67.7s vs. 62.2s).

DISCUSSION

Although no witnessed concussions occurred during rugby play, six players recorded pre- to post-match changes with a mean delay of 4s resulting in seven concussions being subsequently confirmed post-match by health practitioners. All players were medically managed for a return to sports participation.

CONCLUSION

The K-D test was quickly and easily administered making it a practical sideline tool as part of the continuum of concussion assessment tools for junior rugby league players.

Protecting a CT simulator room to accommodate a cyberknife facility

In 2012, a plan to develop Stereotactic treatments using a Cyberknife was unveiled at the Hermitage Medical Clinic, Dublin. Due to planning restrictions the new facility had to be contained in the existing hospital's blue print with the only available location being an unused CT simulation room. The room design would be different from conventional radiotherapy bunkers due to the fact the Cyberknife can fire an unfiltered beam in any direction bar the roof (restriction of 22° above the horizontal). Therefore all walls must be primary barriers with the roof designed to protect against the large leakage radiation resulting from the high MU's used during the treatments. Space consideration indicated that concrete alone could not be used to restrict the radiation beam to acceptable limits. To this end a combination of steel, lead, normal and heavy concrete were used to meet the dose constraints established by the Irish licensing authorities.

Development of secondary mutations in wild-type and mutant EZH2 alleles cooperates to confer resistance to EZH2 inhibitors

The histone methyltransferase Enhancer of Zeste Homolog 2 (EZH2) is frequently dysregulated in cancers, and gain-of-function (GOF) EZH2 mutations have been identified in non-Hodgkin lymphomas. Small-molecule inhibitors against EZH2 demonstrated anti-tumor activity in EZH2-mutated lymphomas and entered clinical trials. Here, we developed models of acquired resistance to EZH2 inhibitor EI1 with EZH2-mutated lymphoma cells. Resistance was generated by secondary mutations in both wild-type (WT) and GOF Y641N EZH2 alleles. These EZH2 mutants retained the substrate specificity of their predecessor complexes but became refractory to biochemical inhibition by EZH2 inhibitors. Resistant cells were able to maintain a high level of H3K27Me3 in the presence of inhibitors. Interestingly, mutation of EZH2 WT alone generated an intermediate resistance phenotype, which is consistent with a previously proposed model of cooperation between EZH2 WT and Y641N mutants to promote tumorigenesis. In addition, the findings presented here have implications for the clinical translation of EZH2 inhibitors and underscore the need to develop novel EZH2 inhibitors to target potential resistance emerging in clinical settings.

Leptin may play a role in bone microstructural alterations in obese children

CONTEXT

Bone mass is low and fracture risk is higher in obese children. Hormonal changes in relation to skeletal microstructure and biomechanics have not been studied in obese children.

OBJECTIVE

The objective of the study was to ascertain the relationships of obesity-related changes in hormones with skeletal microstructure and biomechanics.

DESIGN

High resolution peripheral quantitative computed tomography (HR-pQCT) was used to compare three-dimensional cortical and trabecular microstructure and biomechanics at load-bearing and nonload bearing sites in obese and lean children. The relationship between leptin, adiponectin, testosterone, estrogen, osteocalcin and sclerostin and skeletal microstructure was also determined.

SETTING

The study was conducted at a tertiary pediatric endocrine unit in the United Kingdom.

PARTICIPANTS

Obese and lean children were matched by gender and pubertal stage.

RESULTS

Radial cortical porosity (mean difference -0.01 [95% CI: -0.02, -0.004], P = .003) and cortical pore diameter (mean difference -0.005 mm [95% CI: -0.009, -0.001], P = .011) were lower in obese children. Tibial trabecular thickness was lower (mean difference -0.009 mm [95% CI: -0.014, -0.004], P = .003), and trabecular number was higher (mean difference 0.23 mm(-1) [95% CI: 0.08, 0.38], P = .004) in obese children. At the radius, fat mass percentage negatively correlated with cortical porosity (r = -0.57, P < .001) and pore diameter (r = -0.38, P = .02) and negatively correlated with trabecular thickness (r = -0.62, P < .001) and trabecular von Mises stress (r = -0.39, P = .019) at the tibia. No difference was observed in the other biomechanical parameters of the radius and tibia. Leptin was higher in obese children (805.3 ± 440.6 pg/ml vs 98.1 ± 75.4 pg/ml, P < .001) and was inversely related to radial cortical porosity (r = 0.60, 95% CI: [-0.80, -0.30], P < .001), radial cortical pore diameter (r = 0.51, 95% CI [-0.75, -0.16], P = .002), tibial trabecular thickness (r = 0.55, 95% CI: [-0.78, -0.21], P = .001) and tibial trabecular von Mises stress (r = -0.39, 95% CI: -0.65, 0.04, P = .02).

CONCLUSION

Childhood obesity alters radial and tibial microstructure. Leptin may direct these changes. Despite this, the biomechanical properties of the radius and tibia do not adapt sufficiently in obese children to withstand the increased loading potential from a fall. This may explain the higher incidence of fracture in obese children.

Distributed expertise: qualitative study of a British network of multidisciplinary teams supporting parents of children with chronic kidney disease

BACKGROUND

Long-term childhood conditions are often managed by hospital-based multidisciplinary teams (MDTs) of professionals with discipline specific expertise of a condition, in partnership with parents. However, little evidence exists on professional-parent interactions in this context. An exploration of professionals' accounts of the way they individually and collectively teach parents to manage their child's clinical care at home is, therefore, important for meeting parents' needs, informing policy and educating novice professionals. Using chronic kidney disease as an exemplar this paper reports on one aspect of a study of interactions between professionals and parents in a network of 12 children's kidney units in Britain.

METHODS

We conducted semi-structured, qualitative interviews with a convenience sample of 112 professionals (clinical-psychologists, dietitians, doctors, nurses, pharmacists, play-workers, therapists and social workers), exploring accounts of their parent-educative activity. We analysed data using framework and the concept of distributed expertise.

RESULTS

Four themes emerged that related to the way expertise was distributed within and across teams: (i) recognizing each other's' expertise, (ii) sharing expertise within the MDT, (iii) language interpretation, and (iv) acting as brokers. Two different professional identifications were also seen to co-exist within MDTs, with participants using the term 'we' both as the intra-professional 'we' (relating to the professional identity) when describing expertise within a disciplinary group (for example: 'As dietitians we aim to give tailored advice to optimize children's growth'), and the inter-professional 'we' (a 'team-identification'), when discussing expertise within the team (for example: 'We work as a team and make sure we're all happy with every aspect of their training before they go home').

CONCLUSIONS

This study highlights the dual identifications implicit in 'being professional' in this context (to the team and to one's profession) as well as the unique role that each member of a team contributes to children's care. Our methodology and results have the potential to be transferred to teams managing other conditions.

A prospective cohort study to determine the relationship between serum infliximab concentration and efficacy in patients with luminal Crohn's disease

BACKGROUND

Patients with Crohn's disease (CD) may experience disease relapse on maintenance infliximab. Anti-drug antibodies likely contribute to loss of response, and serum infliximab levels likely correlate with efficacy.

AIM

To prospectively evaluate the relationship between trough serum infliximab concentration and disease activity.

METHODS

Adult patients (N = 327) with a diagnosis of CD who had received at least five consecutive infliximab infusions and who planned to receive at least two additional infusions were enrolled. The Crohn's Disease Activity Index (CDAI), serum infliximab, C-reactive protein (CRP) and antibodies-to-infliximab (ATI) were assessed at baseline, week 4 and week 8. Receiver operating characteristic (ROC) analysis examined the relationship between infliximab concentrations and disease activity.

RESULTS

The mean CDAI score, which decreased 1.05 points between infusions, did not correlate with the mean change in trough infliximab concentration (+0.39 μg/mL; r = 0.099, P = 0.083), but was associated with the mean change in CRP concentration (r = 0.19, P < 0.001). Trough infliximab concentrations below 2.8-4.6 μg/mL best predicted a ≥ 70 point increase in the CDAI between infusions, and those below 2.7-2.8 μg/mL best predicted CRP >5 mg/mL at the second infusion. ATI at either visit decreased the proportion of patients with therapeutic infliximab trough levels compared with patients who were ATI negative (17.5% vs. 77.3% at visit 1 and 13.8% vs. 75.6% at visit 3; P < 0.001 for both comparisons).

CONCLUSIONS

This prospective study confirms the relationship between trough infliximab concentrations, inflammation and antibodies-to-infliximab. Infliximab trough concentrations below 3 μg/mL may increase the likelihood of symptoms and inflammation (ClinicalTrials.gov identifier: NCT00676988).

The impact of non-adherence to medication in patients with schizophrenia on health, social care and societal costs. Analysis of the QUATRO study

Aims. For people with schizophrenia, non-adherence to antipsychotic medications may result in high use of health and other services. The objective of our research was to examine the economic consequences of non-adherence in patients with schizophrenia taking antipsychotic medication. Methods. Data were taken from QUATRO, a randomized controlled trial that drew a sample of adults with schizophrenia receiving psychiatric services in four European cities: Amsterdam, Leipzig, London and Verona. Trial inclusion criteria were a clinical diagnosis of schizophrenia, requiring on-going antipsychotic medication for at least 1-year following baseline assessment, and exhibiting evidence of clinical instability in the year prior to baseline. The patient-completed Medication Adherence Questionnaire (MAQ) was used to calculate the 5-point Morisky index of adherence. Generalized linear models (GLM) were developed to determine the effect of adherence on (i) health and social care and (ii) societal costs before and after treatment, taking into account other potential cost-influencing factors. Results. The effect of non-adherence on costs was mixed. For different groups of services, and according to treatment group assignment, non-adherence was both negatively and positively associated with costs. Conclusions. The impact of non-adherence on costs varies across the types of services used by individuals with schizophrenia.

Neuropsychological assessment as a predictor of weight loss in obese adolescents

BACKGROUND

Obese individuals are known to be more impulsive than their normal-weight counterparts. Impulsivity has been postulated to be a predictor of weight loss.

DESIGN

A pre-post study was designed to determine for the first time whether impulsivity changed with weight loss during a lifestyle and physical activity intervention programme lasting 2-8 weeks.

SUBJECTS

Fifty-three obese adolescents with a body mass index (BMI) of 33.75 ± 7.9 attending a residential camp were tested and compared at baseline with 50 non-obese adolescents with a mean BMI of 20.6 ± 2.3.

MEASUREMENTS

Inhibitory control was measured with the CANTAB (Cambridge Cognition, Cambridge, UK) Stop Signal Task. MATLAB (The Mathswork Inc., Natick, MA, USA) was used to measure the temporal discounting constant.

RESULTS

The obese group was more impulsive than the normal weight adolescents. BMI reduced significantly from 33.76 kg m(-2) to 30.93 kg m(-2) after completing camp. The stop signal reaction time (SSRT) decreased from 225.38 ± 94.22 to 173.76 ± 107.05 ms (n=47, P=0.0001). A reduction in inhibitory control during camp was predictive of those who showed the greatest reduction in BMI (Wilks' Lambda=0.9, F(1,50)=4.85, P=0.034). The number of weeks in camp (Wilks' Lambda=0.83, F(1,50)=9.826, P=0.003) and the age of the adolescents (Wilks' Lambda=0.87, F(1,50)=5.98, P=0.02) were significantly associated with a reduction in inhibitory control as measured by the SSRT. A longer stay in camp was associated with a greater reduction in SSRT (B=25.45, t=2.02, P=0.05). Increasing age had a significant moderating role in the reduction of inhibitory control (B=-0.3, t=-0.034, P=0.05). Temporal discounting for monetary reward also fell significantly during camp.

CONCLUSION

This study highlights the potential to identify those who are obese by using an easy-to-measure psychometric test. Furthermore, it is the first study to report a reduction in impulsivity and an improvement in well-being as part of a government-approved residential camp for obese adolescents. The potential mechanisms for change in impulsivity with weight are discussed.

Efficacy of cyclo-oxygenase inhibition by two commercially available firocoxib products in horses

REASONS FOR PERFORMING STUDY

Two firocoxib preparations for oral use are approved for use in animals in many countries: a chewable canine tablet and an equine paste. In order to reduce costs, many veterinarians use the canine product in horses even though this is an off-label use of the preparation.

OBJECTIVE

To determine the relative efficacy of 2 commercially available firocoxib products to inhibit prostaglandin E₂ (PGE2) synthesis after oral dosing in horses.

STUDY DESIGN

A crossover design using 8 adult horses (n = 4 for each preparation during each treatment period). Body weight range 532-614 kg.

METHODS

Horses received 57 mg of the assigned firocoxib preparation orally once daily for 7 days, with a 14 day washout period between drug crossover. Ten healthy adult light breed horses were used as no-treatment controls. During each treatment period, blood was taken before dosing on Days 0 and 7 and on Day 7 1 h after dosing for ex vivo lipopolysaccharide (LPS) stimulation to induce (PGE₂ ) synthesis. Heparinised plasma was also collected on Day 7 immediately prior to and 1 h after dosing to determine plasma firocoxib concentrations.

RESULTS

In the control group, there was no significant change in LPS-induced PGE2 over time. In contrast, immediately prior to and 1 h after treatment on Day 7, the mean LPS-induced PGE₂ concentration decreased significantly compared to Day 0 values in all treated horses. There was no difference in PGE₂ or plasma firocoxib concentrations between firocoxib treatment groups.

CONCLUSION

In this model, the canine chewable preparation of firocoxib was as effective as the equine paste formulation at reducing LPS-induced PGE₂ synthesis.

POTENTIAL RELEVANCE

The canine chewable preparation of firocoxib may be a suitable alternative to the paste formulation in horses for situations where extra-label drug use can be legally justified. The Summary is available in Chinese - see Supporting information.

Ecohydrological and socioeconomic integration for the operational management of environmental flows

Investment in and operation of flow control infrastructure such as dams, weirs, and regulators can help increase both the health of regulated river ecosystems and the social values derived from them. This requires high-quality and high-resolution spatiotemporal ecohydrological and socioeconomic information. We developed such an information base for integrated environmental flow management in the River Murray in South Australia (SA). A hydrological model was used to identify spatiotemporal inundation dynamics. River ecosystems were classified and mapped as ecohydrological units. Ecological response models were developed to link three aspects of environmental flows (flood duration, timing, and inter-flood period) to the health responses of 16 ecological components at various life stages. Potential infrastructure investments (flow control regulators and irrigation pump relocation) were located by interpreting LiDAR elevation data, digital orthophotography, and wetland mapping information; and infrastructure costs were quantified using engineering cost models. Social values were quantified at a coarse scale as total economic value based on a national survey of willingness-to-pay for four key ecological assets; and at a local scale using mapped ecosystem service values. This information was integrated using a constrained, nonlinear, mixed-integer, compromise programming optimization model and solved using a stochastic Tabu search algorithm. We tested the model uncertainty and sensitivity using 390 Monte Carlo model runs at varying weights of ecological health vs. social values. Integrating ecohydrological and socioeconomic information identified environmental flow management regimes that efficiently achieved both ecological and social objectives. Using an ecologically weighted efficient and socially weighted efficient scenario, we illustrated model outputs including a suite of cost-effective infrastructure investments and an operational plan for new and existing flow control structures including dam releases, weir height manipulation, and regulator operation on a monthly time step. Both the investments and management regimes differed substantially between the two scenarios, suggesting that the choice of weightings on ecological and social objectives is important. This demonstrates the benefit of integrating high-quality and high-resolution spatiotemporal ecohydrological and socioeconomic information for guiding the investment in and operational management of environmental flows.

Characterization of an unusual transmissible spongiform encephalopathy in goat by transmission in knock-in transgenic mice

Bovine spongiform encephalopathy (BSE) is a fatal neurodegenerative disorder of cattle, and its transmission to humans through contaminated food is thought to be the cause of the variant form of Creutzfeldt-Jakob disease. BSE is believed to have spread from the recycling in cattle of ruminant tissue in meat and bone meal (MBM). However, during this time, sheep and goats were also exposed to BSE-contaminated MBM. Both sheep and goats are experimentally susceptible to BSE, and while there have been no reported natural BSE cases in sheep, two goat BSE field cases have been documented. While cases of BSE are rare in small ruminants, the existence of scrapie in both sheep and goats is well established. In the UK, during 2006-2007, a serious outbreak of clinical scrapie was detected in a large dairy goat herd. Subsequently, 200 goats were selected for post-mortem examination, one of which showed biochemical and immunohistochemical features of the disease-associated prion protein (PrP(TSE)) which differed from all other infected goats. In the present study, we investigated this unusual case by performing transmission bioassays into a panel of mouse lines. Following characterization, we found that strain properties such as the ability to transmit to different mouse lines, lesion profile pattern, degree of PrP deposition in the brain and biochemical features of this unusual goat case were neither consistent with goat BSE nor with a goat scrapie herdmate control. However, our results suggest that this unusual case has BSE-like properties and highlights the need for continued surveillance.

Out-of-hours MRI provision in the UK and models of service delivery

AIM

To examine current out-of-hours magnetic resonance imaging (MRI) provision through a snapshot survey of National Health Service (NHS) trusts and to assay how radiographer staffing cover was provided for out-of-hours services.

MATERIALS AND METHODS

A snapshot postal survey was mailed to heads of service of all 234 trusts in England and Wales. A literature search on the models of service delivery and correlation with the authors' internal MRI rota, which has provided a full on-call service for 20 years was undertaken.

RESULTS

The response rate was 45.7% (107 of 234); 14% of responders provided full access to MRI 24 h a day; 63% provided extended weekday service, typically to 20.00 h; and 81% provided a weekend daytime service. The radiographers running the service were typically from the core MRI team. Approximately one-third (29.9%) of trusts provided training in basic brain and spine MRI to non-core MRI team members, but they typically did not participate in out-of-hours provision.

CONCLUSION

There is currently a paucity of information on the provision of out-of-hours MRI in the NHS. However, there is increasing pressure to provide complex imaging out of hours, and in the future, trauma centres may be required to provide MRI to assess spinal injury. The authors describe a system to provide access to MRI at no additional cost to the organization based on 20 years of experience. A minority of surveyed acute NHS trusts have full out-of-hours access to MRI. Demand for MRI provision out of core hours is likely to increase.

Prion seeding activities of mouse scrapie strains with divergent PrPSc protease sensitivities and amyloid plaque content using RT-QuIC and eQuIC

Different transmissible spongiform encephalopathy (TSE)-associated forms of prion protein (e.g. PrP^Sc) can vary markedly in ultrastructure and biochemical characteristics, but each is propagated in the host. PrP^Sc propagation involves conversion from its normal isoform, PrP^C, by a seeded or templated polymerization mechanism. Such a mechanism is also the basis of the RT-QuIC and eQuIC prion assays which use recombinant PrP (rPrP^Sen) as a substrate. These ultrasensitive detection assays have been developed for TSE prions of several host species and sample tissues, but not for murine models which are central to TSE pathogenesis research. Here we have adapted RT-QuIC and eQuIC to various murine prions and evaluated how seeding activity depends on glycophosphatidylinositol (GPI) anchoring and the abundance of amyloid plaques and protease-resistant PrP^Sc (PrP^Res). Scrapie brain dilutions up to 10⁻⁸ and 10⁻¹³ were detected by RT-QuIC and eQuIC, respectively. Comparisons of scrapie-affected wild-type mice and transgenic mice expressing GPI anchorless PrP showed that, although similar concentrations of seeding activity accumulated in brain, the heavily amyloid-laden anchorless mouse tissue seeded more rapid reactions. Next we compared seeding activities in the brains of mice with similar infectivity titers, but widely divergent PrP^Res levels. For this purpose we compared the 263K and 139A scrapie strains in transgenic mice expressing P101L PrP^C. Although the brains of 263K-affected mice had little immunoblot-detectable PrP^Res, RT-QuIC indicated that seeding activity was comparable to that associated with a high-PrP^Res strain, 139A. Thus, in this comparison, RT-QuIC seeding activity correlated more closely with infectivity than with PrP^Res levels. We also found that eQuIC, which incorporates a PrP^Sc immunoprecipitation step, detected seeding activity in plasma from wild-type and anchorless PrP transgenic mice inoculated with 22L, 79A and/or RML scrapie strains. Overall, we conclude that these new mouse-adapted prion seeding assays detect diverse types of PrP^Sc.

Fifty-four emergent cricothyroidotomies: are surgeons reluctant teachers?

BACKGROUND

Emergent cricothyroidotomy remains an uncommon, but life-saving, core procedural training requirement for emergency medicine (EM) physician training. We hypothesized that, although most cricothyroidotomies occur in the emergency department (ED), they are rarely performed by EM physicians.

METHODS

We conducted a retrospective analysis of all emergent cricothyroidotomies performed at two large level one trauma centers over 10 years. Operators and assistants for all procedures were identified, as well as mechanism of injury and patient demographics were examined.

RESULTS

Fifty-four cricothyroidotomies were performed. Patients were: mean age of 50, 80% male and 90% blunt trauma. The most common primary operator was a surgeon (n = 47, 87%), followed by an Emergency Medical Services (EMS) provider (n = 6, 11%) and a EM physician (n = 1, 2%). In all cases, except those performed by EMS, the operator or assistant was an attending surgeon. All EMS procedures resulted in serious complications compared to in-hospital procedures (p < 0.0001).

CONCLUSIONS

1. Pre-hospital cricothyroidotomy results in serious complications. 2. Despite the ubiquitous presence of emergency medicine physicians in the ED, all crico-thyroidotomies were performed by a surgeon, which may represent a serious emergency medicine training deficiency.

The effect of waiting times from general practitioner referral to MRI or orthopaedic consultation for the knee on patient-based outcomes

OBJECTIVES

The purpose of this study was to test for the effect of waiting time from general practitioner (GP) referral to MRI or to orthopaedic consultation on outcomes of patients with knee problems, and to test whether any characteristics of trial participants predicted waiting time to MRI or orthopaedics.

METHODS

We undertook secondary analyses of data on 553 participants from a randomised trial who were recruited from 163 general practices during November 2002 to October 2004.

RESULTS

Of the patients allocated to MRI, 263 (94%) had an MRI, and of those referred to orthopaedics, 236 (86%) had an orthopaedic consultation. The median (interquartile range) waiting time in days from randomisation to MRI was 41.0 (21.0-71.0) and to orthopaedic appointment was 78.5 (54.5-167.5). Waiting time was found to have no significant effect on patient outcome for both the Short Form 36-item (SF-36) physical functioning score (p=0.570) and the Knee Quality of Life 26-item (KQoL-26) physical functioning score (p=0.268). There was weak evidence that males waited less time for their MRI (p=0.049) and older patients waited longer for their orthopaedic referral (p=0.049). For patients who resided in the catchment areas of some centres there were significantly longer waiting times for both MRI and orthopaedic appointment.

CONCLUSION

Where patients reside is a strong predictor of waiting time for access to services such as MRI or orthopaedics. There is no evidence to suggest, however, that this has a significant effect on physical well-being in the short term for patients with knee problems.

Testicular dislocation: the importance of scrotal examination in a trauma patient

Testicular dislocation after blunt perineal trauma is a rare event and a diagnosis that can be easily overlooked. Careful examination can help facilitate early and appropriate treatment. Timely diagnosis and surgical management are of paramount importance to preserve normal spermatogenic function in the dislocated testicle. We describe a case of testicular dislocation and discuss some of the issues surrounding diagnosis and treatment.

MRI in acute and subacute post-traumatic spinal cord injury: pictorial review

STUDY DESIGN

Pictorial review.

OBJECTIVES

To illustrate MRI signs of acute and subacute injury with emphasis on evidence-based links to clinical outcome and implications for treatment.

METHODS

Description of important aspects of MRI techniques and illustration of critical MRI signs important in the assessment of spinal cord injury following trauma, in the acute and subacute stages.

CONCLUSIONS

Familiarity with cord MRI appearances has an important impact on planning the management of the acutely spinal cord injured patient and also identifying complications in the subacute phase particularly in the presence of neurological deterioration.