Comparative accuracy of cervical cancer screening strategies in healthy asymptomatic women: a systematic review and network meta-analysis

To compare all available accuracy data on screening strategies for identifying cervical intraepithelial neoplasia grade ≥ 2 in healthy asymptomatic women, we performed a systematic review and network meta-analysis. MEDLINE and EMBASE were searched up to October 2020 for paired-design studies of cytology and testing for high-risk genotypes of human papillomavirus (hrHPV). The methods used included a duplicate assessment of eligibility, double extraction of quantitative data, validity assessment, random-effects network meta-analysis of test accuracy, and GRADE rating. Twenty-seven prospective studies (185,269 subjects) were included. The combination of cytology (atypical squamous cells of undetermined significance or higher grades) and hrHPV testing (excepting genotyping for HPV 16 or 18 [HPV16/18]) with the either-positive criterion (OR rule) was the most sensitive/least specific, whereas the same combination with the both-positive criterion (AND rule) was the most specific/least sensitive. Compared with standalone cytology, non-HPV16/18 hrHPV assays were more sensitive/less specific. Two algorithms proposed for primary cytological testing or primary hrHPV testing were ranked in the middle as more sensitive/less specific than standalone cytology and the AND rule combinations but more specific/less sensitive than standalone hrHPV testing and the OR rule combination. Further research is needed to assess these results in population-relevant outcomes at the program level.

Comparison of the efficiency and ethical implications of pitfall and Tomahawk traps on Virginia opposums (Didelphis virginiana)

The choice of methods for trapping animals can greatly affect the studies and their results, despite that there are relatively few studies on the matter. Thus, the purpose of this study is to compare two common methods of live trapping (Tomahawk traps and pitfall traps), their efficiency and ethical implications for trapping Virginia opossums (Didelphis virginiana). Traps were located in a paired design, the trapped animals were checked for sex, injuries caused by the trap and stress level, then marked and released in the same spot. At the same time, costs of both trap types were compared. Tomahawk traps were 60 % more efficient to trap opossums but the pitfall traps had better results in all the other categories: were more cost-effective, did not injure the animals as often and were less stressful. Neither type of trap presented bias in sex proportion or number of recaptured animals. In general, both types of traps resulted to be effective, the pitfall trap was the better option in almost all of the categories but has the disadvantage that in the infrequent event of two males being caught on in the same trap, they are likely to fight.

Impacts of Quarterly Sow Mass Vaccination with a Porcine Reproductive and Respiratory Syndrome Virus Type 1 (PRRSV-1) Modified Live Vaccine in Two Herds

In recent years, there has been a considerable increase in the use of Modified Live PRRSV Vaccines (MLV) for mass vaccination in Denmark. The potential risks and negative impact of this strategy have been sparsely studied. The aim of this study was to investigate the impact of quarterly sow mass vaccination in two Danish sow herds. The study was performed as an observational prospective cohort of 120 sows in each of two commercial breeding herds in a paired design. Blood samples were taken from sows and oral fluid samples from nursery pigs (four to ten weeks old) before and after vaccination. The presence of PRRSV-1 RNA was measured by real time quantitative reverse transcription-polymerase chain reaction (RT-qPCR), and the level of PRRSV-1 specific antibodies was measured by two different serological assays. PRRS virus was not detected in the sow herds two days before and two weeks after vaccination, but the vaccine strain virus was detected in the nursery pigs. The prevalence of sows without antibodies towards PRRSV-1 went from 6–15% before vaccination to 1–4% after vaccination depending on the serological assay used, despite the fact that they had previously been repeatedly vaccinated. Four sows tested negative for antibodies in both assays after vaccination.

Life in the Canopy: Using Camera-Traps to Inventory Arboreal Rainforest Mammals in Borneo

Arboreal mammals form a diverse group providing ecologically important functions such as predation, pollination and seed dispersal. However, their cryptic and elusive nature, and the heights at which they live, makes studying these species challenging. Consequently, our knowledge of rainforest mammals is heavily biased towards terrestrial species, limiting our understanding of overall community structure and the possible impacts of human-induced disturbance. We undertook the first in-depth appraisal of an arboreal mammal community in Southeast Asia, using camera-traps set in unlogged and logged tropical rainforest in Sabah, Borneo. Using paired canopy and terrestrial camera-traps at 50 locations (25 in unlogged forest, 25 in logged), we assessed the effectiveness of camera-trapping at characterising the arboreal versus terrestrial community, and tested the influence of strata and forest type on community structure and composition. The paired design detected 55 mammal species across 15,817 camera-trap nights (CTNs), and additional canopy sampling in a subset of trees added a further two arboreal species to the inventory. In total, thirty species were detected exclusively by terrestrial camera-traps, eighteen exclusively by canopy camera-traps, and nine by units set at both heights, demonstrating significant differences between arboreal and terrestrial communities. This pattern was strongest in unlogged forest, reflecting greater structural diversity of this habitat, but held in logged forest as well. Species accumulation curves revealed that canopy camera-trapping significantly boosted species inventories compared to terrestrial-only sampling, and was particularly effective at detecting gliding mammals, rodents and primates. Canopy inventories took longer to reach an asymptote, suggesting that a greater sampling effort is required when deploying canopy camera-traps compared to those set on the ground. We demonstrate that arboreal mammals in Borneo’s rainforest form a diverse and distinct community, and can be sampled effectively using canopy camera-traps. However, the additional costs incurred by sampling in the canopy can be substantial. We provide recommendations to maximise sampling effectiveness, while bringing down costs, to help encourage further study into one of the last frontiers of tropical forest research.

Confidence Intervals and Sample Size to Compare the Predictive Values of Two Diagnostic Tests

A binary diagnostic test is a medical test that is applied to an individual in order to determine the presence or the absence of a certain disease and whose result can be positive or negative. A positive result indicates the presence of the disease, and a negative result indicates the absence. Positive and negative predictive values represent the accuracy of a binary diagnostic test when it is applied to a cohort of individuals, and they are measures of the clinical accuracy of the binary diagnostic test. In this manuscript, we study the comparison of the positive (negative) predictive values of two binary diagnostic tests subject to a paired design through confidence intervals. We have studied confidence intervals for the difference and for the ratio of the two positive (negative) predictive values. Simulation experiments have been carried out to study the asymptotic behavior of the confidence intervals, giving some general rules for application. We also study a method to calculate the sample size to compare the parameters using confidence intervals. We have written a program in R to solve the problems studied in this manuscript. The results have been applied to the diagnosis of colorectal cancer.

A sibling-paired observational study investigating the accumulation and deficiency of toxic and essential elements in children with autism spectrum disorders

This study evaluated if elemental concentrations differed in children with an autism spectrum disorder (ASD) versus normally developing children, at the pre-natal level of development, by means of a sibling-paired design, using deciduous teeth as biomarkers of pre-natal exposure to the elements. A total of 22 families were sampled from the Southern Ontario region (London, Hamilton, Orangeville, Newmarket, Toronto, Kingston and Ottawa) in which the full set of deciduous teeth from all children, where only one child was diagnosed with an ASD, were acquired. An analogous sample was collected from 7 control families. The concentrations of K, Mn, Na, Pb and Sr in the deciduous teeth of children with an ASD were found not to differ from that of their normally developing siblings and the control group (α = 0.01). The concentrations of Mg, Ni, Cu, Fe and Zn were found to be lower in the deciduous teeth of children with an ASD versus their normally developing siblings, while Cr concentrations were found to be elevated (ρ < 0.001). The differences were correlated to a general trend by which the concentrations decreased (or increase, in the case of Cr) in children as the mother conceived more children within the family. This may indicate that the trends and differences observed may be a secondary effect to another underlying condition, presumably at the level of the mother.

A sibling-paired observational study investigating the accumulation and deficiency of toxic and essential elements in children with autism spectrum disorders

This study evaluated if elemental concentrations differed in children with an autism spectrum disorder (ASD) versus normally developing children, at the pre-natal level of development, by means of a sibling-paired design, using deciduous teeth as biomarkers of pre-natal exposure to the elements. A total of 22 families were sampled from the Southern Ontario region (London, Hamilton, Orangeville, Newmarket, Toronto, Kingston and Ottawa) in which the full set of deciduous teeth from all children, where only one child was diagnosed with an ASD, were acquired. An analogous sample was collected from 7 control families. The concentrations of K, Mn, Na, Pb and Sr in the deciduous teeth of children with an ASD were found not to differ from that of their normally developing siblings and the control group (α = 0.01). The concentrations of Mg, Ni, Cu, Fe and Zn were found to be lower in the deciduous teeth of children with an ASD versus their normally developing siblings, while Cr concentrations were found to be elevated (ρ < 0.001). The differences were correlated to a general trend by which the concentrations decreased (or increase, in the case of Cr) in children as the mother conceived more children within the family. This may indicate that the trends and differences observed may be a secondary effect to another underlying condition, presumably at the level of the mother.

Autologous cartilage and fibrin sealant may be superior to conventional fat grafting in preventing physeal bone bridge formation – a pilot study in porcines

Purpose The article compares physeal recovery after insertion of autologous cartilage and a conventional fat graft in a standardized porcine physeal gap model. Presence of a bone bridge was the primary outcome. Methods Ten porcines in two groups of five were included in a paired design. A standardized physeal gap in the distal femur was made in all animals. One group (n = 5) was randomized for deposition of autologous cartilage and a Tisseel® or Tisseel® alone. The autologous cartilage was harvested from the femoral articular surface. The other group was randomized for fat grafting or no grafts at all. All animals were housed for 14 weeks. Magnetic resonance imaging (MRI) was performed at 14 weeks prior to euthanasia. The physis was harvested for histology. Results MRI – Three bone bridges were seen in the fat grafted gaps. All empty gaps formed a bone bridge. No gaps filled with autologous cartilage and Tisseel® resulted in bone bridges. One gap filled with Tisseel® only caused a bone bridge. Histology – The cartilage grafted gaps recovered with physeal-like cartilaginous tissue in histological analysis. Conclusions Fat grafts seems ineffective in preventing bone bridges. The use of autologous cartilage may be superior to the current treatment. However, donor site complications were not investigated. The study serves as a proof of concept study and requires further investigation. Level of evidence III