Contamination in complex healthcare trials: the falls in care homes (FinCH) study experience.

BACKGROUND: Trials are at risk of contamination bias which can occur when participants in the control group are inadvertently exposed to the intervention. This is a particular risk in rehabilitation studies where it is easy for trial interventions to be either intentionally or inadvertently adopted in control settings. The Falls in Care Homes (FinCH) trial is used in this paper as an example of a large randomised controlled trial of a complex intervention to explore the potential risks of contamination bias. We outline the FinCH trial design, present the potential risks from contamination bias, and the strategies used in the design of the trial to minimise or mitigate against this. The FinCH trial was a multi-centre randomised controlled trial, with embedded process evaluation, which evaluated whether systematic training in the use of the Guide to Action Tool for Care Homes reduced falls in care home residents. Data were collected from a number of sources to explore contamination in the FinCH trial. Where specific procedures were adopted to reduce risk of, or mitigate against, contamination, this was recorded. Data were collected from study e-mails, meetings with clinicians, research assistant and clinician network communications, and an embedded process evaluation in six intervention care homes. During the FinCH trial, there were six new falls prevention initiatives implemented outside the study which could have contaminated our intervention and findings. Methods used to minimise contamination were: cluster randomisation at the level of care home; engagement with the clinical community to highlight the risks of early adoption; establishing local collaborators in each site familiar with the local context; signing agreements with NHS falls specialists that they would maintain confidentiality regarding details of the intervention; opening additional research sites; and by raising awareness about the importance of contamination in research among participants. CONCLUSION: Complex rehabilitation trials are at risk of contamination bias. The potential for contamination bias in studies can be minimized by strengthening collaboration and dialogue with the clinical community. Researchers should recognise that clinicians may contaminate a study through lack of research expertise.

Outbreak of Escherichia coli O157 Phage Type 32 linked to the consumption of venison products.

In September 2015, an outbreak of Escherichia coli Phage Type 32 with an indistinguishable multi locus variable number tandem repeat analysis profile was identified in Scotland. Twelve cases were identified; nine primary cases, two secondary and one asymptomatic case. Extensive food history investigations identified venison products containing wild venison produced by a single food business operator as the most likely source of the outbreak. Of the nine primary cases, eight had consumed venison products, and one case had not eaten venison themselves but had handled and cooked raw venison in the household. This was the first reported outbreak of Shiga toxin-producing Escherichia coli (STEC) linked to venison products in the UK, and was also notable due to the implicated products being commercially produced and widely distributed. In contrast, previous venison outbreaks reported from other countries have tended to be smaller and related to individually prepared carcases. The outbreak has highlighted some important knowledge gaps in relation to STEC in venison that are currently been investigated via a number of research studies.

Forensic training- bridging the gap between education and workplace.

Outreach initiatives involves mentoring students, university collaboration, and program creation to diversify roles between academia and forensic practitioners. Mixer exercises foster student-forensic scientist interaction. Emphasis is placed on improving understanding of forensic science, particularly in regions like Southern Africa, where media portrayals often distort perceptions. The outreach initiative aims to correct these misconceptions, promote evidence-based forensic education, and address research shortages through collaboration between forensic laboratories and universities. A permanent committee within the Southern Africa Regional Forensic Science Forum is proposed to facilitate cooperation and coordination. By fostering collaboration and encouraging participation in conferences and research publication, the initiative aims to meet the region's forensic scientist needs.

Quality management system in forensic science: An African perspective.

Critical issues in forensic science quality management have emerged in recent decades. The debate on accrediting quality management systems of forensic laboratories is relevant to the African context. Neuteboom, Ross, Bugeja, Willis, Roux, and Lothridge (2022) have conducted a comprehensive survey exploring critical issues in their article "Quality Management in Forensic Science: A Closer Inspection." Their work is a crucial foundation for our discussion, urging the African forensic community to engage in more in-depth conversations. This letter briefly describes the survey, discussing embracing the Sydney Declaration (SD) for Forensic Sciences and issues of quality management systems comprising standards, accreditation, and potential regulation, and highlights the issue of cognitive competency from an African perspective. This underscores the urgent need for critical dialogue, emphasizing that the time for action is now, and urges practitioners, particularly in Africa, to enhance quality management systems to deliver superior forensic products.

Prkd1 regulates the formation and repair of plasma membrane disruptions (PMD) in osteocytes.

We and others have seen that osteocytes sense high-impact osteogenic mechanical loading via transient plasma membrane disruptions (PMDs) which initiate downstream mechanotransduction. However, a PMD must be repaired for the cell to survive this wounding event. Previous work suggested that the protein Prkd1 (also known as PKCµ) may be a critical component of this PMD repair process, but the specific role of Prkd1 in osteocyte mechanobiology had not yet been tested. We treated MLO-Y4 osteocytes with Prkd1 inhibitors (Go6976, kbNB 142-70, staurosporine) and generated an osteocyte-targeted (Dmp1-Cre) Prkd1 conditional knockout (CKO) mouse. PMD repair rate was measured via laser wounding and FM1-43 dye uptake, PMD formation and post-wounding survival were assessed via fluid flow shear stress (50 dyn/cm2), and in vitro osteocyte mechanotransduction was assessed via measurement of calcium signaling. To test the role of osteocyte Prkd1 in vivo, Prkd1 CKO and their wildtype (WT) littermates were subjected to 2 weeks of unilateral axial tibial loading and loading-induced changes in cortical bone mineral density, geometry, and formation were measured. Prkd1 inhibition or genetic deletion slowed osteocyte PMD repair rate and impaired post-wounding cell survival. These effects could largely be rescued by treating osteocytes with the FDA-approved synthetic copolymer Poloxamer 188 (P188), which was previously shown to facilitate membrane resealing and improve efficiency in the repair rate of PMD in skeletal muscle myocytes. In vivo, while both WT and Prkd1 CKO mice demonstrated anabolic responses to tibial loading, the magnitude of loading-induced increases in tibial BMD, cortical thickness, and periosteal mineralizing surface were blunted in Prkd1 CKO as compared to WT mice. Prkd1 CKO mice also tended to show a smaller relative difference in the number of osteocyte PMD in loaded limbs and showed greater lacunar vacancy, suggestive of impaired post-wounding osteocyte survival. While P188 treatment rescued loading-induced increases in BMD in the Prkd1 CKO mice, it surprisingly further suppressed loading-induced increases in cortical bone thickness and cortical bone formation. Taken together, these data suggest that Prkd1 may play a pivotal role in the regulation and repair of the PMD response in osteocytes and support the idea that PMD repair processes can be pharmacologically targeted to modulate downstream responses, but suggest limited utility of PMD repair-promoting P188 in improving bone anabolic responses to loading.

Long-term panmixia in a cosmopolitan Indo-Pacific coral reef fish and a nebulous genetic boundary with its broadly sympatric sister species.

Phylogeographical studies have shown that some shallow-water marine organisms, such as certain coral reef fishes, lack spatial population structure at oceanic scales, despite vast distances of pelagic habitat between reefs and other dispersal barriers. However, whether these dispersive widespread taxa constitute long-term panmictic populations across their species ranges remains unknown. Conventional phylogeographical inferences frequently fail to distinguish between long-term panmixia and metapopulations connected by gene flow. Moreover, marine organisms have notoriously large effective population sizes that confound population structure detection. Therefore, at what spatial scale marine populations experience independent evolutionary trajectories and ultimately species divergence is still unclear. Here, we present a phylogeographical study of a cosmopolitan Indo-Pacific coral reef fish Naso hexacanthus and its sister species Naso caesius, using two mtDNA and two nDNA markers. The purpose of this study was two-fold: first, to test for broad-scale panmixia in N. hexacanthus by fitting the data to various phylogeographical models within a Bayesian statistical framework, and second, to explore patterns of genetic divergence between the two broadly sympatric species. We report that N. hexacanthus shows little population structure across the Indo-Pacific and a range-wide, long-term panmictic population model best fit the data. Hence, this species presently comprises a single evolutionary unit across much of the tropical Indian and Pacific Oceans. Naso hexacanthus and N. caesius were not reciprocally monophyletic in the mtDNA markers but showed varying degrees of population level divergence in the two nuclear introns. Overall, patterns are consistent with secondary introgression following a period of isolation, which may be attributed to oceanographic conditions of the mid to late Pleistocene, when these two species appear to have diverged.

Do joint registries report true rates of hip dislocation?

BACKGROUND: Despite advances in primary THA, dislocation remains a common complication. In New Zealand (NZ), dislocations are reported to the National Joint Registry (NJR) only when prosthetic components are revised in the treatment of a dislocation. Closed reductions of dislocated hips are not recorded by the NJR. QUESTIONS/PURPOSES: We compared the true dislocation rate for patients receiving primary THA in the Wellington region with the rate reported by the NZ NJR for the same group of patients. METHODS: The NZ NJR identified 570 patients undergoing primary THA from January 1, 2008, to December 31, 2009, with addresses in the Wellington region. The mean age was 67.5 years (range, 27-96 years). The minimum followup was 2 years (mean, 3 years; range, 2-4 years). RESULTS: Six patients required revision of at least one component for dislocation. There was 100% agreement between the hospital database and the NJR. Using the NJR criteria of revision of any component as an end point, the dislocation rate in the Wellington region after primary THA was 1.05%. The hospital database identified a further eight patients who presented with a dislocation of their primary THA and underwent a closed reduction. These patients were not recorded by the NJR. The true rate of all dislocations, which includes closed reductions, was 2.46%. CONCLUSIONS: This article documents the discrepancy between the NZ NJR reported rate of revision for dislocation and the true rate of dislocation in primary THA. We recommend documentation of all dislocations by NJR in their database to allow more accurate comparisons between centers and research outcomes. LEVEL OF EVIDENCE: Level IV, clinical research study. See Guidelines for Authors for a complete description of levels of evidence.

Multifrequency species classification of acoustic-trawl survey data using semi-supervised learning with class discovery.

Acoustic surveys often use multifrequency backscatter to estimate fish and plankton abundance. Direct samples are used to validate species classification of acoustic backscatter, but samples may be sparse or unavailable. A generalized Gaussian mixture model was developed to classify multifrequency acoustic backscatter when not all species classes are known. The classification, based on semi-supervised learning with class discovery, was applied to data collected in the eastern Bering Sea during summers 2004, 2007, and 2008. Walleye pollock, euphausiids, and two other major classes occurring in the upper water column were identified.

Highly crosslinked polyethylene reduces wear in total hip arthroplasty at 5 years.

BACKGROUND: Although hip arthroplasty reliably relieves pain and improves function, problems have arisen with wear and osteolysis. Highly crosslinked polyethylene has been developed to address this problem although at present there is limited clinical evidence it does so longer term. QUESTIONS/PURPOSES: We compared the in vivo wear of standard versus highly crosslinked polyethylene (HXLP) in primary total hip arthroplasty at a minimum of 5-year followup. METHODS: We enrolled 122 patients in a prospective, double-blinded, randomized trial and followed them annually to assess their progress. Annual radiographs were analyzed using previously validated edge detection software to assess for two-dimensional, three-dimensional, and volumetric wear. The mean follow up was 5.5 years (range, 4.1 to 7 years). RESULTS: The two-dimensional wear measurements for HXLP showed lower wear compared to the conventional group (0.05 mm/year versus 0.26 mm/year, respectively). Three-dimensional and volumetric wear were similarly lower in the HXLP group. CONCLUSIONS: Highly crosslinked polyethylene undergoes substantially less wear than conventional polyethylene at medium term. The effect of hip arthroplasty longevity will need to be assessed with longer-term studies, but this may lead to a decreased need for revision as a result of less wear and osteolysis.

Elementary calcium-release units induced by inositol trisphosphate.

The extent to which inositol 1,4,5-trisphosphate (InsP3)-induced calcium signals are localized is a critical parameter for understanding the mechanism of effector activation. The spatial characteristics of InsP3-mediated calcium signals were determined by targeting a dextran-based calcium indicator to intracellular membranes through the in situ addition of a geranylgeranyl lipid group. Elementary calcium-release events observed with this indicator typically lasted less than 33 milliseconds, had diameters less than 2 micrometers, and were uncoupled from each other by the calcium buffer EGTA. Cellwide calcium transients are likely to result from synchronized triggering of such local release events, suggesting that calcium-dependent effector proteins could be selectively activated by localization near sites of local calcium release.

A double-blind, prospective, randomized controlled trial comparing highly cross-linked and conventional polyethylene in primary total hip arthroplasty.

Highly cross-linked polyethylene was developed to reduce articular bearing wear in total hip arthroplasty. In vitro studies have shown reduced wear in comparison with conventional polyethylene. A double-blind, prospective, randomized trial was performed comparing highly cross-linked and conventional polyethylene in 119 patients. The primary outcome variables were linear, 3-dimensional, and volumetric wear as determined by analysis of digitized radiographs using validated wear measurement software. Linear, 3-dimensional, and volumetric wear rates were significantly less in the highly cross-linked polyethylene group between 6 months and 4 years postoperatively (P < .05). The data presented here show that highly cross-linked polyethylene reduces short-term polyethylene wear. The intermediate and long-term clinical results of highly cross-linked polyethylene remain unknown pending further follow-up.

Classifying multi-frequency fisheries acoustic data using a robust probabilistic classification technique.

A robust probabilistic classification technique, using expectation maximization of finite mixture models, is used to analyze multi-frequency fisheries acoustic data. The number of clusters is chosen using the Bayesian Information Criterion. Probabilities of membership to clusters are used to classify each sample. The utility of the technique is demonstrated using two examples: the Gulf of Alaska representing a low-diversity, well-known system; and the Mid-Atlantic Ridge, a species-rich, relatively unknown system.

Measuring the migration of the components and polyethylene wear after total hip arthroplasty: beads and specialised radiographs are not necessary.

AIMS: This paper describes the methodology, validation and reliability of a new computer-assisted method which uses models of the patient's bones and the components to measure their migration and polyethylene wear from radiographs after total hip arthroplasty (THA). MATERIALS AND METHODS: Models of the patient's acetabular and femoral component obtained from the manufacturer and models of the patient's pelvis and femur built from a single computed tomography (CT) scan, are used by a computer program to measure the migration of the components and the penetration of the femoral head from anteroposterior and lateral radiographs taken at follow-up visits. The program simulates the radiographic setup and matches the position and orientation of the models to outlines of the pelvis, the acetabular and femoral component, and femur on radiographs. Changes in position and orientation reflect the migration of the components and the penetration of the femoral head. Validation was performed using radiographs of phantoms simulating known migration and penetration, and the clinical feasibility of measuring migration was assessed in two patients. RESULTS: Migration of the acetabular and femoral components can be measured with limits of agreement (LOA) of 0.37 mm and 0.33 mm, respectively. Penetration of the femoral head can be measured with LOA of 0.161 mm. CONCLUSION: The migration of components and polyethylene wear can be measured without needing specialised radiographs. Accurate measurement may allow earlier prediction of failure after THA. Cite this article: Bone Joint J 2017;99-B:1290-7.

Squamous cell carcinoma of the pinna: which histological features could be used to predict prognosis?

Squamous cell carcinoma (SCC) that originates in the pinna is thought to have a high risk of metastases (up to 16%) compared with under 5% for cutaneous SCC at any other site, and histological features of the primary tumour may provide evidence for further surveillance or treatment. To identify any association between histological features and the risk of metastases we made an electronic search of the histopathological records at the University Hospital Southampton NHS Foundation Trust for all patients who presented with auricular SCC from 2007-2012. Inclusion criteria included origin in the pinna, complete two-year follow up, and no history of immunosuppressive treatment. We looked for histopathological features that were thought to be relevant to metastases. We studied specimens from 192 patients, four of whom developed metastases (2%), each with involved lymph nodes. Perineural invasion and local recurrence were significantly associated with increased risk of metastases (p<0.001 and p=0.006). The overall metastatic rate was much lower than those reported in other studies, and factors other than histological features alone may explain the results. We suggest that although some histological features were significantly associated, they do not predict a high enough risk of metastatic disease to provide evidence for further surveillance or elective lymphadenopathy.

Proteolysis and microstructure of Piacentinu Ennese cheese made using different farm technologies.

The aim of this study was to provide the biochemical and structural characterization of Piacentinu Ennese cheese and to evaluate the impact of different farm technologies on cheese proteolysis and microstructure. Fifteen cheeses were manufactured according to traditional technology, i.e., from raw milk and farmhouse rennet in the absence of starter culture. Pasteurized milk, commercial rennet, and starter were used for production of 20 nontraditional cheeses. Proteolysis in Piacentinu Ennese cheese was monitored during a 2- to 10-mo ripening time. Low rates of overall proteolysis were observed in cheese, as percentages of total N soluble at pH 4.6 and in 12% trichloroacetic acid were about 11.40 and 8.10%, respectively, after 10 mo of age. Patterns of primary proteolysis by urea-PAGE showed that alpha(s)-caseins were degraded to a larger extent than were beta-caseins, although a considerable amount of both caseins was still intact after 10 mo. Reversed phase-HPLC analysis of the cheese peptide fractions showed a slow decrease in the levels of hydrophobic peptides coupled to increasing levels of hydrophilic compounds as the cheese aged. The structural characteristics of Piacentinu Ennese cheese were evaluated by scanning electron microscopy after 2, 4, and 6 mo of age. The micrographs showed a sponge-like structural network with a well-distributed system of empty spaces, originally occupied by whey and fat. The microstructure changed during cheese ripening to become more compact with cavities of smaller size. Farm technology significantly affected cheese proteolysis and microstructure. Nontraditional cheeses had higher levels of pH 4.6-soluble N and showed a larger hydrolysis of alpha(s)-casein fractions by urea-PAGE analysis than did traditional cheeses. Large differences between cheese-types also concerned the patterns of secondary proteolysis. Nontraditional cheeses had higher levels of 12% trichloroacetic acid-soluble N and showed larger proportions of free amino acids and hydrophilic peptides in the HPLC profiles of the corresponding 70% ethanol-soluble N fraction than traditional cheeses. Nontraditional cheeses also had a more open structure with a coarser and less continuous appearance than did traditional cheeses. A large amount of variability in cheese proteolysis and structure within nontraditional treatment reflected farm-dependent changes in manufacturing conditions related to the use of various types of rennet and starter.

Turn up the HEAT.

The recently determined crystal structure of the PR65/A subunit of protein phosphatase 2A reveals the architecture of proteins containing HEAT repeats. The structural properties of this solenoid protein explain many functional characteristics and account for the involvement of solenoids as scaffold, anchoring and adaptor proteins.

Characterization of a dextran-based bifunctional calcium indicator immobilized in cells by the enzymatic addition of isoprenoid lipids.

Cellular processes can be controlled by cell-wide increases in the cytosolic Ca2+ concentration or, alternatively, by localized Ca2+ signals in micro- and nano-domains. The experimental characterization of such localized Ca2+ signals would be facilitated using an immobilized Ca2+ indicator, which could prevent the accelerated spatial spreading of Ca2+ ions that is mediated by binding to diffusible indicators. Here we characterize a dextran-based Ca2+ indicator (CAAX-green) that becomes immobilized in the cytosol by an enzyme-mediated addition of a geranylgeranyl lipid group. CAAX-green consists of a dextran backbone with an attached Ca(2+)-green as well as an 11 residue peptide ending in a C-terminal CAAX-motif. Once introduced into cells by microporation, geranylgeranyl lipid groups are attached to the CAAX peptides by cytosolic enzymes. Measurements in tumor mastcells, myocytes and fibroblasts showed that the indicator becomes membrane attached between 30 min and 1 h following incorporation into the cytoplasm. A time-dependent 10-fold reduction of the diffusion coefficient and a parallel increase in the cytosolic retention after permeabilization indicates that at least 90% of cellular CAAX-green is immobilized. The KD of the indicator in permeabilized cells is 0.65 microM. Overall, these properties make CAAX-green well suited for the investigation of localized Ca2+ signals in a variety of cell types.

REM sleep - by default?

Elements of three old, overlapping theories of REM sleep (REM) function, the Ontogenetic, Homeostatic and Phylogenetic hypotheses, together still provide a plausible framework - that REM (i) is directed towards early cortical development, (ii) "tones up" the sleeping cortex, (iii) can substitute for wakefulness, (iv) has a calming effect. This framework is developed in the light of recent findings. It is argued that the "primitiveness" of REM and its similarity to wakefulness liken it to a default state of "non-wakefulness" or a waking antagonist, anteceding "true" (non-REM) sleep. The "toning up" is reflected by inhibition of motor, sensory and (importantly) emotional systems, together pointing to integrated "flight or fight" activity, that preoccupies/distracts the organism when non-REM is absent and wakefulness unnecessary. Dreaming facilitates this distraction. In rodents, REM can provide stress coping and calming, but REM deprivation procedures incorporating immobility may further enhance stress and confound outcomes. REM "pressure" (e.g. REM rebounds) may be a default from a loss of inhibition of REM by non-REM. REM can be reduced and/or replaced by wakefulness, without adverse effects. REM has little advantage over wakefulness in providing positive cerebral recovery or memory consolidation.

Sleep loss and "divergent" thinking ability.

Although much is known about the impact of sleep loss on many aspects of psychological performance, the effects on divergent ("creative") thinking has received little attention. Twelve subjects went 32 h without sleep, and 12 others acted as normally sleeping controls. All subjects were assessed on the figural and verbal versions of the Torrance Tests of Creative Thinking. As compared with the control condition, sleep loss impaired performance on all test scales (e.g., "flexibility," the ability to change strategy, and "originality," generation of unusual ideas) for both versions, even on an initial 5-min test component. In an attempt at further understanding of whether these findings might be explained solely by a loss of motivation, two additional short and stimulating tests were also used--a word fluency task incorporating high incentive to do well and a challenging nonverbal planning test. Performance at these tasks was still significantly impaired by sleep loss. Increased perseveration was clearly apparent. Apparently, 1 night of sleep loss can affect divergent thinking. This contrasts with the outcome for convergent thinking tasks, which are more resilient to short-term sleep loss.