Systematic review and meta-analysis of the growth and rupture rates of small abdominal aortic aneurysms: implications for surveillance intervals and their cost-effectiveness.

BACKGROUND: Small abdominal aortic aneurysms (AAAs; 3.0-5.4 cm in diameter) are usually asymptomatic and managed by regular ultrasound surveillance until they grow to a diameter threshold (commonly 5.5 cm) at which surgical intervention is considered. The choice of appropriate surveillance intervals is governed by the growth and rupture rates of small AAAs, as well as their relative cost-effectiveness. OBJECTIVES: The aim of this series of studies was to inform the evidence base for small AAA surveillance strategies. This was achieved by literature review, collation and analysis of individual patient data, a focus group and health economic modelling. DATA SOURCES: We undertook systematic literature reviews of growth rates and rupture rates of small AAAs. The databases MEDLINE, EMBASE on OvidSP, Cochrane Central Register of Controlled Trials 2009 Issue 4, ClinicalTrials.gov, and controlled-trials.com were searched from inception up until the end of 2009. We also obtained individual data on 15,475 patients from 18 surveillance studies. REVIEW METHODS: Systematic reviews of publications identified 15 studies providing small AAA growth rates, and 14 studies with small AAA rupture rates, up to December 2009 (later updated to September 2012). We developed statistical methods to analyse individual surveillance data, including the effects of patient characteristics, to inform the choice of surveillance intervals and provide inputs for health economic modelling. We updated an existing health economic model of AAA screening to address the cost-effectiveness of different surveillance intervals. RESULTS: In the literature reviews, the mean growth rate was 2.3 mm/year and the reported rupture rates varied between 0 and 1.6 ruptures per 100 person-years. Growth rates increased markedly with aneurysm diameter, but insufficient detail was available to guide surveillance intervals. Based on individual surveillance data, for each 0.5-cm increase in AAA diameter, growth rates increased by about 0.5 mm/year and rupture rates doubled. To control the risk of exceeding 5.5 cm to below 10% in men, on average a 7-year surveillance interval is sufficient for a 3.0-cm aneurysm, whereas an 8-month interval is necessary for a 5.0-cm aneurysm. To control the risk of rupture to below 1%, the corresponding estimated surveillance intervals are 9 years and 17 months. Average growth rates were higher in smokers (by 0.35 mm/year) and lower in patients with diabetes (by 0.51 mm/year). Rupture rates were almost fourfold higher in women than men, doubled in current smokers and increased with higher blood pressure. Increasing the surveillance interval from 1 to 2 years for the smallest aneurysms (3.0-4.4 cm) decreased costs and led to a positive net benefit. For the larger aneurysms (4.5-5.4 cm), increasing surveillance intervals from 3 to 6 months led to equivalent cost-effectiveness. LIMITATIONS: There were no clear reasons why the growth rates varied substantially between studies. Uniform diagnostic criteria for rupture were not available. The long-term cost-effectiveness results may be susceptible to the modelling assumptions made. CONCLUSIONS: Surveillance intervals of several years are clinically acceptable for men with AAAs in the range 3.0-4.0 cm. Intervals of around 1 year are suitable for 4.0-4.9-cm AAAs, whereas intervals of 6 months would be acceptable for 5.0-5.4-cm AAAs. These intervals are longer than those currently employed in the UK AAA screening programmes. Lengthening surveillance intervals for the smallest aneurysms was also shown to be cost-effective. Future work should focus on optimising surveillance intervals for women, studying whether or not the threshold for surgery should depend on patient characteristics, evaluating the usefulness of surveillance for those with aortic diameters of 2.5-2.9 cm, and developing interventions that may reduce the growth or rupture rates of small AAAs. FUNDING: The National Institute for Health Research Health Technology Assessment programme

A synopsis of the genus Plantago L. in Tasmania

An account of the genus Plantago in Tasmania is presented. The taxonomic, biogeographic and cytological relationships of the genus are reviewed. Current knowledge on ecological and cytological data for the Tasmanian taxa is included and a key to the Tasmanian species is presented

One-relator Kaehler groups

We prove that a one-relator group $G$ is K\"ahler if and only if either $G$ is finite cyclic or $G$ is isomorphic to the fundamental group of a compact orbifold Riemann surface of genus $g > 0$ with at most one cone point of order $n$: $$< a_1\, b_1\, \,...\, a_g\, b_g\, \mid\, (\prod_{i=1}^g [a_i\, b_i])^n>\, .$$Comment: v2: 9pgs. no figs. Final version, to appear in "Geometry and Topology

Structural and floristic variation in the forest communities of the West Tamar, Tasmania

The forest communities in the West Tamar were sampled by a stratified random process using 55 plots selected after preliminary analysis of 243 Forestry Commission continuous forest inventory plots, which occur in the area. A total of 13 floristic units were recognised and described. The relationship of the floristic units to changing water availability, drainage, soil fertility and fire frequency are assessed and the problems of structural versus floristic classifications of forest types are discussed

Rainforest in eastern Tasmania- floristics and conservation

Six floristic communities are described from rainforest in northern and eastern Tasmania. The communities occur in lower rainfall areas, where they are often restricted to fire-protected sites. They have climatic envelopes which are significantly distinct from each other and from rainforest in higher rainfall areas. The conservation status of the communities is assessed

The vegetation of Tasman Peninsula

Although its area is less than 1% of Tasmania, Tasman Peninsula possesses more than one- third of the total native vascular plants of the State. The number of species present is close to that predicted by the theories of island biogeography. There are 70 Tasmanian endemic vascular plant species present, representing 13 % of the total. This figure is lower than that expected on a proportional basis due to the absence from the peninsula of the distinctively Tasmanian alpine, wet and oligotrophic western environments. There are two vascular plants known only from the peninsula. Nevertheless there is a distinctly local flavour to the flora due to those components held in common with other predominantly lowland dolerite parts of southeastern Tasmania. The vegetation types present on the peninsula include coastal heaths, dune vegetation and wetlands, dry and wet sc!erophyll forests and some small areas ofsubalpine scrub and rainforests. The structure and composition of the vegetation on the peninsula reflect climatic, topographic, firing and biotic influences. Thus dry sclerophyll forests grade into wet sclerophyll forests as moisture availability increases . The forests grade into heaths as sites become more exposed to the prevailing salt-laden onshore winds. Within a particular vegetation type, the composition is influenced by local climate and landform but is also attributable to local drainage conditions, geological substrate and fire history. The plant species and communities present are, some exceptions, moderately well- conserved, but sensitivity in future management will be required to retain the character conferred on the peninsula by its native vegetation

Monitoring for the effects of climate change on the flora values of the Tasmanian Wilderness World Heritage Area

Climate change is predicted to have significant impacts on Australia's biodiversity including the flora values of the Tasmanian Wilderness World Heritage Area (TWWHA). The current nature and direction of climate change impacts on biodiversity are uncertain. It is therefore prudent to establish a flora monitoring framework that captures a range of aspects of the vegetation values within the TWWHA. Monitoring will assist researchers and land managers in identifying values at high risk from climate change and allow for mitigating measures to be implemented. We outline criteria for a monitoring framework and recommend 14 sites be adopted as key flora monitoring locations within western and southwestern Tasmania. The sites that have been chosen - many of which have been the focus of previous research - provide a broad coverage of TWWHA environments allowing the opportunity for existing data to be used as a baseline to measure change

A descriptive ecology of the vegetation in the lower Gordon River basin, Tasmania

The vegetation of the Lower Gordon Ri vel' Basin consists of rainforest, sclerophyll forest, scrub and sedgeland-heath, each of which is composed of a number of plant communities forming an intricate mosaic. Field studies conducted over three summer seasons suggest that differential fire regimes are the primary determinants of the composition, structure and distribution of the major vegetation types. Climatic, topographic and edaphic factors play a relatively minor role except through their interaction with the fire regime. The observed patterns and processes in the major vegetation types can be interpreted readily in terms of vegetation succession and ecological drift, but the ubiquity of diffuse ecotones argues against the occurrence of stable fire cycles

Tissue resolved, gene structure refined equine transcriptome.

BackgroundTranscriptome interpretation relies on a good-quality reference transcriptome for accurate quantification of gene expression as well as functional analysis of genetic variants. The current annotation of the horse genome lacks the specificity and sensitivity necessary to assess gene expression especially at the isoform level, and suffers from insufficient annotation of untranslated regions (UTR) usage. We built an annotation pipeline for horse and used it to integrate 1.9 billion reads from multiple RNA-seq data sets into a new refined transcriptome.ResultsThis equine transcriptome integrates eight different tissues from 59 individuals and improves gene structure&nbsp;and isoform resolution, while providing considerable tissue-specific information. We utilized four levels of transcript filtration in our pipeline, aimed at producing several transcriptome versions that are suitable for different downstream analyses. Our most refined transcriptome includes 36,876 genes and 76,125 isoforms, with 6474 candidate transcriptional loci novel to the equine transcriptome.ConclusionsWe have employed a variety of descriptive statistics and figures that demonstrate the quality and content of the transcriptome. The equine transcriptomes that are provided by this pipeline show the best tissue-specific resolution of any equine transcriptome to date and are flexible for several downstream analyses. We encourage the integration of further equine transcriptomes with our annotation pipeline to continue and improve the equine transcriptome