Analysis of mitochondrial control region DNA variation in New Zealand's brushtail possums (Trichosurus vulpecula) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University

Brushtail possums (Trichosurus vulpecula) were first introduced from Australia to New Zealand in 1858 to establish a fur industry. Currently numbering more than 65 million, they are recognised as the most important mammalian pest in New Zealand, because of the environmental and agricultural damage they cause. Possums act as a wildlife reservoir of bovine tuberculosis (Tb) and, as such, threaten New Zealand's multi-million dollar beef and dairy industry. Eliminating bovine Tb in livestock requires removal of contact with infected possums. This is mainly achieved through the intensive poisoning of areas of known wildlife Tb infection and the establishment around them of zones of low possum density (known as buffer zones) adjacent to at-risk farmland. Not only does this result in lower possum density, and thus fewer dispersing possums, but may also affect the movement patterns of possums. Measurement of gene frequency differences between populations associated with a buffer zone would allow a qualitative estimate of the effect of buffer zones on limiting possum movement. The mitochondrial DNA (mtDNA) control region is an effective marker for detecting intraspccific genetic structure because it has a high mutation rate, lack of recombination and uniparental mode of inheritance. An extensive survey of brushtail possum mtDNA control region variation in New Zealand was conducted to quantify levels of variation and thus assess the utility of the mtDNA control region as a marker for detecting genetic differentiation between possum populations. Nine haplotypes were found among 70 possums from throughout New Zealand. Most of the variation (six haplotypes) was concentrated in the North Island, and the most widespread haplotype (occurring in all four islands surveyed) was also the most common - found in 67% of possums surveyed. The technique of single stranded conformation polymorphism (SSCP) was developed for the brushtail possum so that a quick, cost-effective and sensitive method for surveying mtDNA control region variation in large numbers of individuals was available. This assay was applied to screen the variation in possums separated by small spatial scales associated with two buffer zones in the South Island. A total of 234 possums were screened, with 98.7% found to possess the same haplotype. The other 1.3%, all from one location, possessed a second haplotype. The extremely low levels of variation makes it highly unlikely that surveys of variation in mtDNA will be able to detect an effect of buffer zones on possum movement, at least in the South Island. Areas of higher variation, such as certain parts on the North Island, would be better candidates for testing the effect of barriers such as buffer zones on genetic differentiation between possum populations

Systematic review of the current status of cadaveric simulation for surgical training

Background: There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training. Methods: A PRISMA‐compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool. Results: A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7). Conclusion: There is an abundance of relatively low‐quality evidence showing that cadaveric simulation induces short‐term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre

Balancing Selection Drives the Maintenance of Genetic Variation in Drosophila Antimicrobial Peptides

This work is licensed under a Creative Commons Attribution 4.0 International License.Genes involved in immune defense against pathogens provide some of the most well-known examples of both directional and balancing selection. Antimicrobial peptides (AMPs) are innate immune effector genes, playing a key role in pathogen clearance in many species, including Drosophila. Conflicting lines of evidence have suggested that AMPs may be under directional, balancing, or purifying selection. Here, we use both a linear model and control-gene-based approach to show that balancing selection is an important force shaping AMP diversity in Drosophila. In Drosophila melanogaster, this is most clearly observed in ancestral African populations. Furthermore, the signature of balancing selection is even more striking once background selection has been accounted for. Balancing selection also acts on AMPs in Drosophila mauritiana, an isolated island endemic separated from D. melanogaster by about 4 Myr of evolution. This suggests that balancing selection may be broadly acting to maintain adaptive diversity in Drosophila AMPs, as has been found in other taxa

Could stool collection devices help increase uptake to bowel cancer screening programmes?

Objective: We aimed to understand the usage and acceptability of a faecal collection device (FCD) amongst participants of the NHS Bowel Cancer Screening Programme in order to influence future uptake. Setting: Men and women completing faecal occult blood test (FOBt) retests as part of the routine Bowel Cancer Screening Programme in Eastern England. Methods: A FCD and questionnaire was sent to all potential retest participants during a 1 month period collecting information on prior stool collection methods and ease of use and usefulness of the enclosed FCD. Results: Of 1087 invitations to participate, 679 (62.5%) participants returned their questionnaire. Of these 429 (63.2%) trialled the FCD at least once. 163 (38.4%) found the device made collecting their sample easier than previously, with 189 (44.6%) finding it made collection more difficult and 72 (17.0%) feeling it made no difference. Similar numbers reported finding that the FCD made collecting the sample more pleasant (130, 31.5%), less pleasant (103, 25.0%) and no different (179, 43.4%) compared to previous collection without a FCD. Conclusion: Although a small proportion of participants found the FCD helpful a considerable majority did not or did not use it at all. Offering FCDs is unlikely to produce a substantial increase in bowel cancer screening uptake

The Genetic Basis of Natural Variation in Drosophila melanogaster Immune Defense against Enterococcus faecalis

This work is licensed under a Creative Commons Attribution 4.0 International License.Dissecting the genetic basis of natural variation in disease response in hosts provides insights into the coevolutionary dynamics of host-pathogen interactions. Here, a genome-wide association study of Drosophila melanogaster survival after infection with the Gram-positive entomopathogenic bacterium Enterococcus faecalis is reported. There was considerable variation in defense against E. faecalis infection among inbred lines of the Drosophila Genetics Reference Panel. We identified single nucleotide polymorphisms associated with six genes with a significant (p < 10−08, corresponding to a false discovery rate of 2.4%) association with survival, none of which were canonical immune genes. To validate the role of these genes in immune defense, their expression was knocked-down using RNAi and survival of infected hosts was followed, which confirmed a role for the genes krishah and S6k in immune defense. We further identified a putative role for the Bomanin gene BomBc1 (also known as IM23), in E. faecalis infection response. This study adds to the growing set of association studies for infection in Drosophila melanogaster and suggests that the genetic causes of variation in immune defense differ for different pathogens

Investing in updating: how do conclusions change when Cochrane systematic reviews are updated?

BACKGROUND: Cochrane systematic reviews aim to provide readers with the most up-to-date evidence on the effects of healthcare interventions. The policy of updating Cochrane reviews every two years consumes valuable time and resources and may not be appropriate for all reviews. The objective of this study was to examine the effect of updating Cochrane systematic reviews over a four year period. METHODS: This descriptive study examined all completed systematic reviews in the Cochrane Database of Systematic Reviews (CDSR) Issue 2, 1998. The latest version of each of these reviews was then identified in CDSR Issue 2, 2002 and changes in the review were described. For reviews that were updated within this time period and had additional studies, we determined whether their conclusion had changed and if there were factors that were predictive of this change. RESULTS: A total of 377 complete reviews were published in CDSR Issue 2, 1998. In Issue 2, 2002, 14 of these reviews were withdrawn and one was split, leaving 362 reviews to examine for the purpose of this study. Of these reviews, 254 (70%) were updated. Of these updated reviews, 23 (9%) had a change in conclusion. Both an increase in precision and a change in statistical significance of the primary outcome were predictive of a change in conclusion of the review. CONCLUSION: The concerns around a lack of updating for some reviews may not be justified considering the small proportion of updated reviews that resulted in a changed conclusion. A priority-setting approach to the updating of Cochrane systematic reviews may be more appropriate than a time-based approach. Updating all reviews as frequently as every two years may not be necessary, however some reviews may need to be updated more often than every two years

Совершенствование управления краткосрочными активами предприятия (на примере ОАО «СтанкоГомель»)

Determining which reference genes have the highest stability, and are therefore appropriate for normalising data, is a crucial step in the design of real-time quantitative PCR (qPCR) gene expression studies. This is particularly warranted in non-model and ecologically important species for which appropriate reference genes are lacking, such as the mallard-a key reservoir of many diseases with relevance for human and livestock health. Previous studies assessing gene expression changes as a consequence of infection in mallards have nearly universally used β-actin and/or GAPDH as reference genes without confirming their suitability as normalisers. The use of reference genes at random, without regard for stability of expression across treatment groups, can result in erroneous interpretation of data. Here, eleven putative reference genes for use in gene expression studies of the mallard were evaluated, across six different tissues, using a low pathogenic avian influenza A virus infection model. Tissue type influenced the selection of reference genes, whereby different genes were stable in blood, spleen, lung, gastrointestinal tract and colon. β-actin and GAPDH generally displayed low stability and are therefore inappropriate reference genes in many cases. The use of different algorithms (GeNorm and NormFinder) affected stability rankings, but for both algorithms it was possible to find a combination of two stable reference genes with which to normalise qPCR data in mallards. These results highlight the importance of validating the choice of normalising reference genes before conducting gene expression studies in ducks. The fact that nearly all previous studies of the influence of pathogen infection on mallard gene expression have used a single, non-validated reference gene is problematic. The toolkit of putative reference genes provided here offers a solid foundation for future studies of gene expression in mallards and other waterfowl

Sociodemographic Variations in the Uptake of Faecal Immunochemical Tests in Primary Care

Background: Faecal Immunochemical Testing (FIT) usage for symptomatic patients is increasing, but variations in use by sociodemographics are unknown. We introduced FIT for symptomatic patients in November 2017. Aim: Identify whether demographics, ethnicity or social deprivation affect FIT return in symptomatic patients. Design and Setting: FIT was introduced as a triage tool in Primary Care and was mandated for all colorectal referrals (except rectal bleeding/mass) to secondary care. FIT was used, alongside full blood count and ferritin, to stratify colorectal cancer risk. Method: All referrals November 2017-December 2021 were retrospectively reviewed. Sociodemographic factors affecting FIT return were analysed by multivariate logistic regression. Results: 35,289 patients returned their index FIT (90.7%), 3631 (9.3%) did not. On multivariate analysis, males were less likely to return FIT (OR 1.11, 95%CI 1.03-1.19). Patients over 65 were more likely to return FIT (OR 0.78 for non-return, 95%CI 0.72-0.83). Unreturned FIT was more than doubled in the most compared to the least deprived (OR 2.20, 95%CI 1.99-2.43). Patients from Asian (OR 1.82, 95%CI 1.58-2.10), Black (OR 1.21, 95%CI 0.98-1.49) and Mixed/Other ethnic groups (OR 1.29, 95%CI 1.05-1.59) were more likely to not return FIT compared to White ethnicity. 599 colorectal cancers were detected (1.5%), 561 in those who returned a first FIT request, 38 in those who did not. Conclusion: FIT return in those suspected of having colorectal cancer varies by gender, age, ethnicity, and socioeconomic deprivation. Strategies to mitigate effects on FIT return and colorectal cancer detection should be considered as FIT usage expands

Sexual selection protects against extinction

Reproduction through sex carries substantial costs, mainly because only half of sexual adults produce offspring. It has been theorised that these costs could be countered if sex allows sexual selection to clear the universal fitness constraint of mutation load. Under sexual selection, competition between (usually) males, and mate choice by (usually) females create important intraspecific filters for reproductive success, so that only a subset of males gains paternity. If reproductive success under sexual selection is dependent on individual condition, which depends on mutation load, then sexually selected filtering through ‘genic capture’ could offset the costs of sex because it provides genetic benefits to populations. Here, we test this theory experimentally by comparing whether populations with histories of strong versus weak sexual selection purge mutation load and resist extinction differently. After evolving replicate populations of the flour beetle Tribolium castaneum for ~7 years under conditions that differed solely in the strengths of sexual selection, we revealed mutation load using inbreeding. Lineages from populations that had previously experienced strong sexual selection were resilient to extinction and maintained fitness under inbreeding, with some families continuing to survive after 20 generations of sib × sib mating. By contrast, lineages derived from populations that experienced weak or non-existent sexual selection showed rapid fitness declines under inbreeding, and all were extinct after generation 10. Multiple mutations across the genome with individually small effects can be difficult to clear, yet sum to a significant fitness load; our findings reveal that sexual selection reduces this load, improving population viability in the face of genetic stress

Faecal immunochemical testing and blood tests for prioritization of urgent colorectal cancer referrals in symptomatic patients: a 2-year evaluation

BackgroundA novel pathway incorporating faecal immunochemical testing (FIT) for rapid colorectal cancer diagnosis (RCCD) was introduced in 2017. This paper reports on the service evaluation after 2 years of pathway implementation.MethodsThe RCCD protocol was based on FIT, blood results and symptoms to stratify adult patients in primary care. Two-week-wait (2WW) investigation was indicated for patients with rectal bleeding, rectal mass and faecal haemoglobin (fHb) level of 10 µg Hb/g faeces or above or 4 µg Hb/g faeces or more in the presence of anaemia, low ferritin or thrombocytosis, in all other symptom groups. Patients with 100 µg Hb/g faeces or above had expedited investigation . A retrospective audit of colorectal cancer detected between 2017 and 2019 was conducted, fHb thresholds were reviewed and critically assessed for cancer diagnoses.ResultsIn 2 years, 14788 FIT tests were dispatched with 13361 (90.4 per cent) completed returns. Overall, fHb was less than 4 µg Hb/g faeces in 9208 results (68.9 per cent), 4–9.9 µg Hb/g in 1583 (11.8 per cent), 10–99.9 µg Hb/g in 1850 (13.8 per cent) and 100 µg Hb/g faeces or above in 720 (5.4 per cent). During follow-up (median 10.4 months), 227 colorectal cancers were diagnosed. The cancer detection rate was 0.1 per cent in patients with fHb below 4 µg Hb/g faeces, 0.6 per cent in those with fHb 4–9.9 µg Hb/g faeces, 3.3 per cent for fHb 10–99.9 µg Hb/g faeces and 20.7 per cent for fHb 100 µg Hb/g faeces or above. The detection rate in the cohort with 10–19.9 µg Hb/g faeces was 1.4 per cent, below the National Institute for Health and Care Excellence threshold for urgent referral. The colorectal cancer rate in patients with fHb below 20 µg Hb/g faeces was less than 0.3 per cent.ConclusionUse of FIT to "rule out" urgent referral from primary care misses a small number of cases. The threshold for referral may be adjusted with blood results to improve stratification