179 research outputs found

    Setting up an adult congenital heart programme

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    With the growing number of adult patients with congenital heart defects in the developing world, many institutions and practice groups are beginning or growing their adult congenital heart disease (ACHD) programmes. In this paper, we review:■ Practical considerations in establishing a clinic (Where will your patients come from? How many new referrals annually can you anticipate?);■ Transition and transfer challenges (can you avoid the loss to care of children with moderate and complex congenital heart defects? Is there an agreed age of transfer policy? Is there an available and effective transition process?);■ Institutional considerations (do you really have the support of your institution? Where should your program be located? Where will you admit your inpatients?);■ Patient care imperatives (how will you commit to excellent patient care? How will you meet the needs of your patients? Clearly designate which patients you will need to refer out and to which services they will be referred);■ The composition of the ACHD team (begin with two ACHD cardiologists and skilled echocardiography, consider a mix of pediatric trained and adult trained cardiologists, grow from there in a modular fashion if you can to include more multidisciplinary team members, and duplicate essentialservice positions); and■ Organisation and accreditation of ACHD care (ACHD services need to be managed differently than pediatric services across the full diagnostic and treatment clinicalspectrum)

    An Overview of Mites on Grapevine and the Discovery of a new Phytoseiidae Species; Typhlodromus (Typhlodromus) spiceae

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    The common grapevine (Vitis vinifera L.) is the main species used for wine making, with South Africa being one of the top wine exporting countries. Grapevine is vulnerable to a range of pests, includingmites. We present an overview of phytophagous and predatory mites on grapevine in South Africa anddescribe a new phytoseiid species which was discovered in the winelands region of Wellington, SouthAfrica. Grapevine shoots with leaves were collected over two growing seasons at four farms in Wellington.A nursery, mother block and a commercial vineyard were selected on each farm. The mites were removedwith a mite brushing machine and slide mounted. The Phytoseiidae Database, as well the most recentrelevant literature were used in confirming the new species. Illustrations of the new species were madeusing photographs taken by Zeiss Axioskop TM Research that included a Zen Soft Imaging System. Thenew Typhlodromus species, Typhlodromus (Typhlodromus) spiceae sp.n., is set apart from closely relatedspecies by setae Z4 being 0.7 times the length of Z5 and by having a short, saccular and thick-walledspermathecal. This species was found together with one phytophagous mite species (Brevipalpus lewisi)and several predatory mite species (Typhlodromus praeacutus, Typhlodromus saevus, Eusieus addoensis). Akey to identify females of the South African species of Typhlodromus (Typhlodromus) is provided

    Fine-scale abundance and distribution of wild silk moth pupae

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    Although several factors influence herbivore insect distributions at any particular scale, the most important determinants are likely to differ between species with different life histories. Identifying what these factors are and how they relate to life history forms an important component of understanding the population dynamics of species, and the habitat requirements necessary for their conservation. The pupal stage of two wild silk moth species, Gonometa postica Walker and G. rufobrunnea Aurivillius (Lepidoptera: Lasiocampidae), is the target of harvesting practices that are totally dependent on the availability of pupae from natural populations. Consequently, and partly due to poor knowledge of the species’ biology, there is substantial interest in the distribution of pupae among and within trees for both these species. It was investigated whether between- and within-tree pupal distributions in these two species are non-random, and if so, whether there are relationships between pupation site use and tree characteristics such as tree size, available pupation space and branch position. Between-tree patterns in pupal abundance were random in terms of absolute spatial position, but markedly nonrandom with respect to tree characteristics. The apparent G. postica pupae were aggregated on large larval host plants, whereas the cryptic G. rufobrunnea pupae were aggregated on non-host plants. These patterns reflect the life history differences of the two species. In contrast, at the within-tree scale, branch position, aspect and tree shape influenced pupation site choice similarly for both species. These patterns might be related to microclimate. Documenting between-tree and within-tree patterns in Gonometa pupal distributions is the first step towards explaining pupation site selection, as well as identifying possible evolutionarily selective factors in the species, and generating testable hypotheses from these.Centre of Excellence for Invasion Biolog

    Can life-history and defence traits predict the population dynamics and natural enemy responses of insect herbivores?

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    1. Life-history differences between herbivorous insects with eruptive and latent population dynamics are potentially useful for predicting population size variability. An association has also been demonstrated between herbivorous insect defence traits and the responses of various natural enemies. 2. Here predictions of population dynamics and natural enemy responses based on life-history and defence traits are tested using Gonometa postica Walker and G. rufobrunnea Aurivillius, two Southern Hemisphere Macrolepidoptera (Lasiocampidae) species. The temporal and spatial variation in pupal abundance and patterns of pupal parasitism and predation for both species are described and quantified for the first time. 3. Eleven sites were sampled over four generations across the region where both species have historically reached high population densities. Although there was evidence suggesting that population synchrony is driven by weather patterns, site-specific environmental differences contributed to the observed population variability. This study is the first to quantify the extent of population size variability of a species with an intermediate position on the eruptive – latent population dynamic gradient, where data on insect population dynamics is scarce. 4. Support for the life-history – population dynamic relationship was found, as intermediate population size variability for these species was observed. Larval and pupal defence traits, however, were poor and inconsistent predictors of mortality rate. Pupal cocoon structure differences, previously documented for these Gonometa species, may in fact explain the interspecific differences in natural enemy responses found. 5. Predicted population dynamics and natural enemy responses may, however, be overridden by ecological conditions. Nevertheless, life-history and defence traits provide a useful basis for predicting population dynamics of poorly studied species.Centre of Excellence for Invasion Biolog

    Landscape corridors: Possible dangers?

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    Ctr Invas Bio

    Bleeding and thrombotic risk in pregnant women with Fontan physiology

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    Background/objectives Pregnancy may potentiate the inherent hypercoagulability of the Fontan circulation, thereby amplifying adverse events. This study sought to evaluate thrombosis and bleeding risk in pregnant women with a Fontan.  Methods We performed a retrospective observational cohort study across 13 international centres and recorded data on thrombotic and bleeding events, antithrombotic therapies and pre-pregnancy thrombotic risk factors.  Results We analysed 84 women with Fontan physiology undergoing 108 pregnancies, average gestation 33 +/- 5 weeks. The most common antithrombotic therapy in pregnancy was aspirin (ASA, 47 pregnancies (43.5%)). Heparin (unfractionated (UFH) or low molecular weight (LMWH)) was prescribed in 32 pregnancies (30%) and vitamin K antagonist (VKA) in 10 pregnancies (9%). Three pregnancies were complicated by thrombotic events (2.8%). Thirty-eight pregnancies (35%) were complicated by bleeding, of which 5 (13%) were severe. Most bleeds were obstetric, occurring antepartum (45%) and postpartum (42%). The use of therapeutic heparin (OR 15.6, 95% CI 1.88 to 129, p=0.006), VKA (OR 11.7, 95% CI 1.06 to 130, p=0.032) or any combination of anticoagulation medication (OR 13.0, 95% CI 1.13 to 150, p=0.032) were significantly associated with bleeding events, while ASA (OR 5.41, 95% CI 0.73 to 40.4, p=0.067) and prophylactic heparin were not (OR 4.68, 95% CI 0.488 to 44.9, p=0.096). Conclusions Current antithrombotic strategies appear effective at attenuating thrombotic risk in pregnant women with a Fontan. However, this comes with high (>30%) bleeding risk, of which 13% are life threatening. Achieving haemostatic balance is challenging in pregnant women with a Fontan, necessitating individualised risk-adjusted counselling and therapeutic approaches that are monitored during the course of pregnancy

    Valuing Insect Pollination Services with Cost of Replacement

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    Value estimates of ecosystem goods and services are useful to justify the allocation of resources towards conservation, but inconclusive estimates risk unsustainable resource allocations. Here we present replacement costs as a more accurate value estimate of insect pollination as an ecosystem service, although this method could also be applied to other services. The importance of insect pollination to agriculture is unequivocal. However, whether this service is largely provided by wild pollinators (genuine ecosystem service) or managed pollinators (commercial service), and which of these requires immediate action amidst reports of pollinator decline, remains contested. If crop pollination is used to argue for biodiversity conservation, clear distinction should be made between values of managed- and wild pollination services. Current methods either under-estimate or over-estimate the pollination service value, and make use of criticised general insect and managed pollinator dependence factors. We apply the theoretical concept of ascribing a value to a service by calculating the cost to replace it, as a novel way of valuing wild and managed pollination services. Adjusted insect and managed pollinator dependence factors were used to estimate the cost of replacing insect- and managed pollination services for the Western Cape deciduous fruit industry of South Africa. Using pollen dusting and hand pollination as suitable replacements, we value pollination services significantly higher than current market prices for commercial pollination, although lower than traditional proportional estimates. The complexity associated with inclusive value estimation of pollination services required several defendable assumptions, but made estimates more inclusive than previous attempts. Consequently this study provides the basis for continued improvement in context specific pollination service value estimates

    Percutaneous closure of atrial septal defects leads to normalisation of atrial and ventricular volumes

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    Background: Percutaneous closure of atrial septal defects (ASDs) should potentially reduce right heart volumes by removing left-to-right shunting. Due to ventricular interdependence, this may be associated with impaired left ventricular filling and potentially function. Furthermore, atrial changes post-ASD closure have been poorly understood and may be important for understanding risk of atrial arrhythmia post-ASD closure. Cardiovascular magnetic resonance (CMR) is an accurate and reproducible imaging modality for the assessment of cardiac function and volumes. We assessed cardiac volumes pre- and post-percutaneous ASD closure using CMR. Methods: Consecutive patients (n = 23) underwent CMR pre- and 6 months post-ASD closure. Steady state free precession cine CMR was performed using contiguous slices in both short and long axis views through the ASD. Data was collected for assessment of left and right atrial, ventricular end diastolic volumes (EDV) and end systolic volumes (ESV). Data is presented as mean ± SD, volumes as mL, and paired t-testing performed between groups. Statistical significance was taken as p < 0.05. Results: There was a significant reduction in right ventricular volumes at 6 months post-ASD closure (RVEDV: 208.7 ± 76.7 vs. 140.6 ± 60.4 mL, p < 0.0001) and RVEF was significantly increased (RVEF 35.5 ± 15.5 vs. 42.0 ± 15.2%, p = 0.025). There was a significant increase in the left ventricular volumes (LVEDV 84.8 ± 32.3 vs. 106.3 ± 38.1 mL, p = 0.003 and LVESV 37.4 ± 20.9 vs. 46.8 ± 18.5 mL, p = 0.016). However, there was no significant difference in LVEF and LV mass post-ASD closure. There was a significant reduction in right atrial volumes at 6 months post-ASD closure (pre-closure 110.5 ± 55.7 vs. post-closure 90.7 ± 69.3 mL, p = 0.019). Although there was a trend to a decrease in left atrial volumes post-ASD closure, this was not statistically significant (84.5 ± 34.8 mL to 81.8 ± 44.2 mL, p = NS). Conclusion: ASD closure leads to normalisation of ventricular volumes and also a reduction in right atrial volume. Further follow-up is required to assess how this predicts outcomes such as risk of atrial arrhythmias after such procedures.Karen SL Teo, Benjamin K Dundon, Payman Molaee, Kerry F Williams, Angelo Carbone, Michael A Brown, Matthew I Worthley, Patrick J Disney, Prashanthan Sanders and Stephen G Worthle
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