5,186 results for 2012

  • Invertebrate community composition differs between invasive herb alligator weed and native sedges

    Bassett, Imogen; Paynter, Quentin; Beggs, Jacqueline (2012-05)

    Journal article
    The University of Auckland Library

    Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator weed) and native sedges (Isolepis prolifer and Schoenoplectus tabernaemontani) in a New Zealand lake. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Lower invertebrate abundance, richness and proportionally fewer specialists were predicted on A. philoxeroides compared to native sedges, but with greatest differences between A. philoxeroides and S. tabernaemontani. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Invertebrate abundance showed taxa-specific responses, rather than consistently lower abundance on A. philoxeroides. Nevertheless, as predicted, invertebrate fauna of A. philoxeroides was more similar to that of I. prolifer than to S. tabernaemontani. The prediction of a depauperate native fauna on A. philoxeroides received support from some but not all taxa. All vegetation types hosted generalist-dominated invertebrate communities with simple guild structures. The enemy release hypothesis thus had minimal ability to predict patterns in this system. Results suggest the extent of architectural and chemical differences between native and invasive vegetation may be useful in predicting the extent to which they will host different invertebrate communities. However, invertebrate ecology also affects whether invertebrate taxa respond positively or negatively to weed invasion. Thus, exotic vegetation may support distinct invertebrate communities despite similar overall invertebrate abundance to native vegetation.

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  • Characterising alligator weed (Alternanthera philoxeroides; Amaranthaceae) invasion at a northern New Zealand lake

    Bassett, Imogen; Paynter, Quentin; Hankin, Robin; Beggs, Jacqueline (2012)

    Journal article
    The University of Auckland Library

    Exotic plant invasions are a key threat to New Zealand biodiversity. Alligator weed (Alternanthera philoxeroides; Amaranthaceae) is an invasive, herbaceous weed native to South America. Little is known about its dynamics in natural ecosystems in its introduced range, despite known agricultural impacts. We quantified alligator weed infestation at Lake Rotokawau, Northland, and investigated alligator weed???s relationship with other vegetation, both native and exotic, over a year (Nov. 2005 to Sep. 2006). We also examined the relationship between native vegetation and ???other??? exotic vegetation at the site. Alligator weed, at its peak in spring, covered over 20% of the surveyed lake margin. Plant community composition of plots without alligator weed differed significantly from invaded plots even when alligator weed itself was removed from the analysis. Uninvaded plots were characterised by low beta-diversity and predominantly terrestrial plant species, with Phormium tenax contributing 41% of within-group similarity. In contrast, invaded plots had higher beta-diversity and were characterised by a variety of emergent sedges and herbs. Alligator weed cover was negatively related to cover of natives but not cover of ???other??? exotics. Alligator weed cover was not related to species richness of natives or ???other??? exotics. ???Other??? exotic species were positively related to native cover and richness, likely due to shared responses to favourable environmental conditions.

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  • Antibiotics for bronchiectasis exacerbations in children: rationale and study protocol for a randomised placebo-controlled trial

    Chang, AB; Grimwood, K; Robertson, CF; Wilson, AC; van Asperen, PP; O'Grady, K-AF; Sloots, TP; Torzillo, PJ; Bailey, EJ; McCallum, GB; Masters, IB; Byrnes, Catherine; Chatfield, MD; Buntain, HM; Mackay, IM; Morris, PS (2012-08-31)

    Journal article
    The University of Auckland Library

    Background: Despite bronchiectasis being increasingly recognised as an important cause of chronic respiratory morbidity in both indigenous and non-indigenous settings globally, high quality evidence to inform management is scarce. It is assumed that antibiotics are efficacious for all bronchiectasis exacerbations, but not all practitioners agree. Inadequately treated exacerbations may risk lung function deterioration. Our study tests the hypothesis that both oral azithromycin and amoxicillin-clavulanic acid are superior to placebo at improving resolution rates of respiratory exacerbations by day 14 in children with bronchiectasis unrelated to cystic fibrosis.Methods: We are conducting a bronchiectasis exacerbation study (BEST), which is a multicentre, randomised, double-blind, double-dummy, placebo-controlled, parallel group trial, in five centres (Brisbane, Perth, Darwin, Melbourne, Auckland). In the component of BEST presented here, 189 children fulfilling inclusion criteria are randomised (allocation-concealed) to receive amoxicillin-clavulanic acid (22.5 mg/kg twice daily) with placebo-azithromycin; azithromycin (5 mg/kg daily) with placebo-amoxicillin-clavulanic acid; or placebo-azithromycin with placebo-amoxicillin-clavulanic acid for 14 days. Clinical data and a paediatric cough-specific quality of life score are obtained at baseline, at the start and resolution of exacerbations, and at day 14. In most children, blood and deep nasal swabs are also collected at the same time points. The primary outcome is the proportion of children whose exacerbations have resolved at day 14. The main secondary outcome is the paediatric cough-specific quality of life score. Other outcomes are time to next exacerbation; requirement for hospitalisation; duration of exacerbation; and spirometry data. Descriptive viral and bacteriological data from nasal samples and blood markers will also be reported.Discussion: Effective, evidence-based management of exacerbations in people with bronchiectasis is clinically important. Yet, there are few randomised controlled trials (RCTs) in the neglected area of non-cystic fibrosis bronchiectasis. Indeed, no published RCTs addressing the treatment of bronchiectasis exacerbations in children exist. Our multicentre, double-blind RCT is designed to determine if azithromycin and amoxicillin-clavulanic acid, compared with placebo, improve symptom resolution on day 14 in children with acute respiratory exacerbations. Our planned assessment of the predictors of antibiotic response, the role of antibiotic-resistant respiratory pathogens, and whether early treatment with antibiotics affects duration and time to the next exacerbation, are also all novel.Trial registration: Australia and New Zealand Clinical Trials Register (ANZCTR) number ACTRN12612000011886.

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  • Myocardial twitch duration and the dependence of oxygen consumption on pressure-volume area: Experiments and modelling

    Han, June; Tran, Kenneth; Taberner, Andrew; Nickerson, David; Kirton, Robert; Nielsen, Poul; Ward, Marie-Louise; Nash, Martyn; Crampin, Edmund; Loiselle, Denis (2012)

    Journal article
    The University of Auckland Library

    We tested the proposition that linear length-dependence of twitch duration underlies the well-characterised linear dependence of oxygen consumption (VO[sub]2[/sub]) on pressure-volume area (PVA) in the heart. By way of experimental simplification, we reduced the problem from three dimensions to one by substituting cardiac trabeculae for the classically-investigated whole-heart. This allowed adoption of stress-length area (SLA) as a surrogate for PVA, and heat as a proxy for VO[sub]2[/sub]. Heat and stress (force per cross-sectional area), at a range of muscle lengths and at both 1 mM and 2 mM [Ca[sup]2+[/sup]][sub]o[/sub], were recorded from continuously superfused rat right-ventricular trabeculae undergoing fixed-end contractions. The heat-SLA relations of trabeculae (reported here, for the first time) are linear. Twitch duration increases monotonically (but not strictly linearly) with muscle length. We probed the cellular mechanisms of this phenomenon by determining: (i) the length-dependence of the duration of the Ca[sup]2+[/sup]-transient, (ii) the length-dependence of the rate of force redevelopment following a length-impulse (an index of Ca[sup]2+[/sup]-binding to troponin-C), (iii) the effect on the simulated time-course of the twitch of progressive deletion of length- and Ca[sup]2+[/sup]-dependent mechanisms of crossbridge cooperativity, using a detailed mathematical model of the crossbridge cycle, and (iv) the conditions required to achieve these multiple length-dependencies, using a greatly simplified model of twitch mechano-energetics. From the results of these four independent investigations, we infer that the linearity of the heat-SLA relation (and, by analogy, the VO[sub]2[/sub]-PVA relation) is remarkably robust in the face of departures from linearity of length-dependent twitch duration.

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  • The conservation status of New Zealand Hymenoptera

    Ward, Darren; Early, JW; Schnitzler, F-R; Hitchmough, RA; Stringer, IAN (2012-06)

    Journal article
    The University of Auckland Library

    Two species of New Zealand Hymenoptera, a colletid bee Leioproctus nunui and a gasteruptiid Gasteruption scintillans, are considered Threatened: both are ranked Nationally Critical. Twenty taxa are At Risk, comprising two taxa that are Declining with the remainder classified as Naturally Uncommon. A further 47 taxa are Data Deficient, and 669 known species are either Not Threatened or Introduced and Naturalised.

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  • The influence of tissue hydration on equine hoof capsule deformation and energy storage assessed using finite element methods

    Ramsey, Glenn; Hunter, Peter; Nash, Martyn (2012-02)

    Journal article
    The University of Auckland Library

    The mechanical properties of equine hoof horn are known to vary with moisture content and this property is sometimes utilised for interventions that attempt to reshape the hoof capsule. However, the relationship of moisture content modulation to the mechanics of the whole hoof is unknown. This study explores the effect of moisture variation on hoof capsule mechanics and, in particular, deflections and stored elastic energy variations in the hoof. A finite element model of the hoof was used. The hoof capsule tissue was modelled using finite elasticity with a heterogeneous transversely isotropic material relation, in which the elastic parameters were varied according to the moisture content of the tissue. The laminar junction and sole corium were modelled using an exponential Fung-type constitutive relation fitted to published data. The distal phalanx bone was modelled as a homogeneous isotropic material. Substrate interaction was modelled by contact with a rigid plate and loads typical of a trot were applied. Different scenarios were modelled where the moisture content of the hoof wall was varied from 40% to 100% of the fully hydrated case. Results demonstrated that hoof capsule deflections and stored elastic energy in the capsule increased monotonically with increasing moisture content. Stored energy in the laminar junction and sole corium remained constant. The mechanical behaviour of the hoof capsule is sensitive to variation in moisture content and this mechanism may provide a way to modulate impact energy transmission. Experimental validations of hoof models should control for moisture content to improve reliability.

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  • Interocular Comparison by In Vivo Confocal Microscopy of the 2-Dimensional Architecture of the Normal Human Corneal Subbasal Nerve Plexus

    Misra, Stuti; Craig, Jennifer; McGhee, Charles; Patel, Dipika (2012-12)

    Journal article
    The University of Auckland Library

    PURPOSE: To investigate the configuration of the living human corneal subbasal nerve plexus in paired eyes of normal subjects using in vivo confocal microscopy. METHODS: Laser scanning in vivo confocal microscopy was performed on both corneas of healthy human subjects, and a grid fixation pattern facilitated examination of consistent areas of central to midperipheral cornea. Macromedia/Adobe Freehand 10 was used to manually arrange images into contiguous montages. The subbasal nerve density and overall patterns were analyzed. RESULTS: Both eyes of 6 subjects (3 women and 3 men, aged between 25 and 36 years) were examined. In all subjects, the subbasal nerve plexus exhibited a clockwise whorl configuration inferior to the central cornea. The mean subbasal nerve density at the whorl was 39.17 ?? 4.95 mm/mm and 41.36 ?? 4.19 mm/mm in the right and left eyes, respectively. There was no significant difference in the nerve density between the eyes (P = 0.61). Bland and Altman analysis confirmed high intraobserver repeatability and moderate interobserver repeatability. CONCLUSIONS: This study reveals the marked similarities between the corneal subbasal nerve plexus configuration in the right and left eyes of the living human cornea, highlighting that the typical mirror-image symmetry in corneal topographic patterns is not obeyed in respect to corneal innervation and that a clockwise orientation of the subbasal plexus is typically encountered. There was no statistical difference in the subbasal nerve density between the eyes.

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  • Insight from modelling can address controversial observations

    Ramsey, Glenn; Hunter, Peter; Nash, Martyn (2012-07)

    Journal article
    The University of Auckland Library

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  • Detailed hoof morphometry is sparsely documented

    Ramsey, Glenn; Hunter, Peter; Nash, Martyn (2012-07)

    Journal article
    The University of Auckland Library

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  • Relating components of pressure-volume area in Suga's formulation of cardiac energetics to components of the stress-time integral

    Han, June; Taberner, Andrew; Tran, Kenneth; Nickerson, David; Nash, Martyn; Nielsen, Poul; Crampin, EJ; Loiselle, Denis (2012)

    Journal article
    The University of Auckland Library

    The concept of pressure-volume area (PVA) in whole heart studies is central to the phenome- nological description of cardiac energetics proposed by Suga and colleagues (Physiol Rev 70: 247???277, 1990). PVA consists of two components: an approxi- mately rectangular work loop (W) and an approximately triangular region of potential energy (U). In the case of isovolumic contractions, PVA consists entirely of U. The utility of Suga???s description of cardiac energetics is the observation that the oxygen consumption of the heart (V ?? O2) is linearly dependent on PVA. By using isolated ventricular trabeculae, we found a basis on which to correlate the compo- nents of stress-length area (SLA; i.e., the 1-D equivalent of PVA) with specific regions of the stress-time integral (STI; i.e., the area under the force-time profile of a single twitch). In each case, proportionality obtains and is robust, independent of the type of twitch contraction (isometric or isotonic), and insensitive to changes of preload or afterload. We apply our results by examining retrospectively the interpretations reached in three independent studies published in the literature.

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  • Comparison of the Gibbs and Suga formulations of cardiac energetics: The demise of "isoefficiency"

    Han, June; Taberner, Andrew; Tran, Kenneth; Goo, S; Nickerson, David; Nash, Martyn; Nielsen, Poul; Crampin, EJ; Loiselle, Denis (2012)

    Journal article
    The University of Auckland Library

    Two very different sorts of experiments have characterized the field of cardiac energetics over the past three decades. In one of these, Gibbs and colleagues measured the heat production of isolated papillary muscles undergoing isometric contractions and afterloaded isotonic contractions. The former generated roughly linear heat vs. force relationships. The latter generated enthalpy-load relationships, the peak values of which occurred at or near peak isometric force, i.e., at a relative load of unity. Contractile efficiency showed a pronounced dependence on afterload. By contrast, Suga and coworkers measured the oxygen consumption (V ??O2) while recording the pressure-volume-time work loops of blood-perfused isolated dog hearts. From the associated (linear) end-systolic pressure-volume relations they derived a quantity labeled pressure-volume area (PVA), consisting of the sum of pressure-volume work and unspent elastic energy and showed that this was linearly correlated with V ??O2 over a wide range of conditions. This linear dependence imposed isoefficiency: constant contractile efficiency independent of afterload. Neither these data nor those of Gibbs and colleagues are in dispute. Nevertheless, despite numerous attempts over the years, no demonstration of either compatibility or incompatibility of these disparate characterizations of cardiac energetics has been forthcoming. We demonstrate that compatibility between the two formulations is thwarted by the concept of isoefficiency, the thermodynamic basis of which we show to be untenable.

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  • Myocardial contractility and regional work throughout the cardiac cycle using FEM and MRI

    Wang, Yang; Ennis, DB; Cowan, Brett; Young, Alistair; Nash, Martyn (2012)

    Conference item
    The University of Auckland Library

    The role of myocardial contractile force in the progression of cardiovascular diseases such as heart failure (HF) has been the focus of many studies. In order to better understand the mechanisms underlying compromised contractility, finite element (FE) modelling of ventricular mechanics is a useful tool. Distributions of active fibre stress during systole were estimated using left ventricular (LV) FE models that incorporated in vivo MRI tagging data and concurrent LV endocardial pressure recordings to parameterise a time-varying model of myocardial contraction. For five canine hearts, the calcium dependent contractile stress increased to peaks ranging from 33 kPa to 57 kPa during systole. Regional distributions of fibre stretch, stress, and myocardial work were examined in each case. Using this type of integrative biophysical modelling to compare normal and pathological cases will elucidate the underlying physiological mechanisms of cardiac mechanical dysfunction.

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  • Estimation of in vivo human myocardial fibre strain by integrating diffusion tensor and tagged MRI using FE modelling

    Wang, Y; Casta, C; Croisille, P; Clarysse, P; Zhu, Y-M; Cowan, Brett; Young, Alistair; Nash, Martyn (2012)

    Conference item
    The University of Auckland Library

    In this study, we propose a methodology to estimate 3Dtime maps of left ventricular fibre strain from human structural and dynamic MRI data. A finite element model integrates fibre principal direction throughout the left ventricle from an ex vivo human diffusion tensor MRI acquisition and motion from tagged MRI. This combination enables the estimation of fibre strain and its variation throughout the cardiac cycle. The long-term goal of this study is to apply this technique to an atlas of human fibre orientations and to investigate the importance of having subject-specific fibre orientation for fibre strain analysis.

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  • Unsupervised segmentation and personalised FE modelling of in vivo human myocardial mechanics based on an MRI atlas

    Wang, Y; Hoogendoorn, C; Engelbrecht, G; Frangi, AF; Young, Alistair; Hunter, Peter; Nash, Martyn (2012)

    Conference item
    The University of Auckland Library

    We have developed techniques to automatically generate personalised biomechanical models of patients' hearts based on 3D cardiac images. We demonstrate this approach using multi-slice computed tomography images. Unsupervised segmentation was performed using non-rigid image registration with a segmented image. A finite element model was automatically fitted to the segmented data of the left ventricle. Passive and contractile myocardial mechanical properties were tuned to match the segmented surface geometries at end-diastole and end-systole, respectively. Global and regional indices of myocardial mechanics, including cardiac wall and myofibre strain distributions, were then quantified. This automated biomechanical modelling approach to cardiac image analysis provided noninvasive methods to characterise heart function, and may provide new quantitative diagnostic markers for heart failure.

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  • Biotic resistance: Facilitation between invasive Homoptera and invasive ants limits the establishment of an introduced weed biocontrol agent in New Zealand

    Paynter, Q; Forgie, SA; Winks, CJ; Peterson, PG; Ward, Darren; Nicholson, L; Van Zoelen, R (2012-11)

    Journal article
    The University of Auckland Library

    The boneseed leafroller moth Tortrix s.l. sp. ???chyrsanthemoides??? (BSLR), originating from Western Cape Province, South African was introduced into New Zealand for the biological control (biocontrol) of a South African shrub boneseed Chrysanthemoides monilifera ssp. monilifera but has established only patchily. We investigated factors hypothesized to influence its establishment success. Field surveys and manipulative experiments ruled out climate as a factor and indicated that establishment failure was associated with predation, mainly by invasive ants of South American (Linepithema humile), and Australian (Doleromyrma darwiniana; Nylanderia sp.) origin that were attracted to invasive honeydew-secreting scale insects (Parasaissetia nigra and Saissetia oleae) found on boneseed. An exclusion experiment showed that unless invertebrate predators (mainly invasive ants and Vespula and Polistes wasps) were excluded, BSLR larvae did not survive to maturity on boneseed plants infested with scale insects. This study supports the notion that insect agents that feed externally on the host-plant are susceptible to predation in the presence of ant-tended Homoptera and that if ant-tended Homoptera are present, candidate agents should be prioritized accordingly.

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  • More than just records: Analysing Natural History Collections for biodiversity planning

    Ward, Darren (2012-11)

    Journal article
    The University of Auckland Library

    Natural History Collections (NHCs) play a central role as sources of data for biodiversity and conservation. Yet, few NHCs have examined whether the data they contain is adequately representative of local biodiversity. I examined over 15,000 databased records of Hymenoptera from 1435 locations across New Zealand collected over the past 90 years. These records are assessed in terms of their geographical, temporal, and environmental coverage across New Zealand. Results showed that the spatial coverage of records was significantly biased, with the top four areas contributing over 51% of all records. Temporal biases were also evident, with a large proportion (40%) of records collected within a short time period. The lack of repeat visits to specific locations indicated that the current set of NHC records would be of limited use for long-term ecological research. Consequently, analyses and interpretation of historical data, for example, shifts in community composition, would be limited. However, in general, NHC records provided good coverage of the diversity of New Zealand habitats and climatic environments, although fewer NHC records were represented at cooler temperatures (5000 mm/yr). Analyses of NHCs can be greatly enhanced by using simple techniques that examine collection records in terms of environmental and geographical space. NHCs that initiate a systematic sampling strategy will provide higher quality data for biodiversity research than ad hoc or point samples, as is currently the norm. Although NHCs provide a rich source of information they could be far better utilised in a range of large-scale ecological and conservation studies.

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  • Clinical implementation of finite element models in pelvic ring surgery for prediction of implant behavior: A case report

    B??hme, J; Shim, Bo; H??ch, A; M??tze, M; M??ller, C; Josten, C (2012-11)

    Journal article
    The University of Auckland Library

    BACKGROUND: Osteosyntheses to stabilize pelvic-ring fractures were developed for younger patients, and are not universally indicated for elderly people. We present the results of parallel-arranged numerical simulations of fixation treatment that an elderly patient with a bagatelle-injured pelvic ring fracture received using a patient-specific finite element model. METHODS: The clinical course of an osteosynthetic stabilized pelvic ring fracture, based on an actual case, was numerically simulated using a patient-specific finite element model. FINDINGS: A previously validated finite element model of a human pelvis was customized with computed tomography data from a patient with a stabilized pelvic-ring fracture. Numerical simulation was used to analyze primary stability. The clinical process, represented by radiologic examinations, was compared with the results from the finite element simulation. Implant loosening as well as newly-occurring fractures were shown to coincide with regions with the highest stress levels. INTERPRETATION: The results from the patient-specific finite element model closely resembled the actual clinical course especially in terms of the location of high strain concentration and subsequent implant loosening. This indicates that patient-specific finite element models have a potential to play an important role in planning osteosynthesis according to biomechanical stability.

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  • Who will be heard? Qualitative research and legal decisions about facilitated communication

    Morton, Mary Winston (2012)

    Book item
    The University of Auckland Library

    This volume of transformed research utilizes an activist approach to examine the notion that nothing is apolitical.

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  • White matter microstructural abnormalities in the frontal lobe of adults with antisocial personality disorder

    Sundram, Frederick; Deeley, Q; Sarkar, S; Daly, E; Latham, R; Craig, M; Raczek, M; Fahy, T; Picchioni, M; UK AIMS Network; Barker, GJ; Murphy, DGM (2012-02)

    Journal article
    The University of Auckland Library

    Antisocial personality disorder (ASPD) and psychopathy involve significant interpersonal and behavioural impairments. However, little is known about their underlying neurobiology and in particular, abnormalities in white matter (WM) microstructure. A preliminary diffusion tensor magnetic resonance imaging (DT-MRI) study of adult psychopaths employing tractography revealed abnormalities in the right uncinate fasciculus (UF) (Craig et al., 2009), indicating fronto-limbic disconnectivity. However, it is not clear whether WM abnormalities are restricted to this tract or are or more widespread, including other tracts which are involved in connectivity with the frontal lobe. We performed whole brain voxel-based analyses on WM fractional anisotropy (FA) and mean diffusivity (MD) maps acquired with DT-MRI to compare 15 adults with ASPD and healthy age, handedness and IQ-matched controls. Also, within ASPD subjects we related differences in FA and MD to measures of psychopathy. Significant WM FA reduction and MD increases were found respectively in ASPD subjects relative to controls. FA was bilaterally reduced in the genu of corpus callosum while in the right frontal lobe FA reduction was found in the UF, inferior fronto-occipital fasciculus (IFOF), anterior corona radiata and anterior limb and genu of the internal capsule. These differences negatively correlated with measures of psychopathy. Also in the right frontal lobe, increased MD was found in the IFOF and UF, and the corpus callosum and anterior corona radiata. There was a significant positive correlation between MD and psychopathy scores. Conclusions The present study confirms a previous report of reduced FA in the UF. Additionally, we report for the first time, FA deficits in tracts involved in interhemispheric as well as frontal lobe connectivity in conjunction with MD increases in the frontal lobe. Hence, we provide evidence of significant WM microstructural abnormalities in frontal brain regions in ASPD and psychopathy.

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  • Azithromycin for Indigenous children with bronchiectasis: study protocol for a multi-centre randomized controlled trial

    Valery, PC; Morris, PS; Grimwood, K; Torzillo, PJ; Byrnes, Catherine; Masters, IB; Bauert, PA; McCallum, GB; Mobberly, C; Chang, AB (2012-08-14)

    Journal article
    The University of Auckland Library

    Background: The prevalence of chronic suppurative lung disease (CSLD) and bronchiectasis unrelated to cystic fibrosis (CF) among Indigenous children in Australia, New Zealand and Alaska is very high. Antibiotics are a major component of treatment and are used both on a short or long-term basis. One aim of long-term or maintenance antibiotics is to reduce the frequency of acute pulmonary exacerbations and symptoms. However, there are few studies investigating the efficacy of long-term antibiotic use for CSLD and non-CF bronchiectasis among children. This study tests the hypothesis that azithromycin administered once a week as maintenance antibiotic treatment will reduce the rate of pulmonary exacerbations in Indigenous children with bronchiectasis.Methods/design: We are conducting a multicentre, randomised, double-blind, placebo controlled clinical trial in Australia and New Zealand. Inclusion criteria are: Aboriginal, Torres Strait Islander, Maori or Pacific Island children aged 1 to 8 years, diagnosed with bronchiectasis (or probable bronchiectasis) with no underlying disease identified (such as CF or primary immunodeficiency), and having had at least one episode of pulmonary exacerbation in the last 12 months. After informed consent, children are randomised to receive either azithromycin (30 mg/kg once a week) or placebo (once a week) for 12-24 months from study entry. Primary outcomes are the rate of pulmonary exacerbations and time to pulmonary exacerbation determined by review of patient medical records. Secondary outcomes include length and severity of pulmonary exacerbation episodes, changes in growth, school loss, respiratory symptoms, forced expiratory volume in 1-second (FEV 1 ; for children ???6 years), and sputum characteristics. Safety endpoints include serious adverse events. Antibiotic resistance in respiratory bacterial pathogens colonising the nasopharynx is monitored. Data derived from medical records and clinical assessments every 3 to 4 months for up to 24 months from study entry are recorded on standardised forms.Discussion: Should this trial demonstrate that azithromycin is efficacious in reducing the number of pulmonary exacerbations, it will provide a much-needed rationale for the use of long-term antibiotics in the medical management of bronchiectasis in Indigenous children.Trial registration: Australian New Zealand Clinical Trials Registry: ACTRN12610000383066. ?? 2012 Valery et al.; licensee BioMed Central Ltd.

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