231 results for Conference poster

  • Mechanisms Of Differences In Ventilation Distribution In The Upright, Supine, And Prone Postures

    Tawhai, Merryn; Hedges, Kerry (2011-05-13)

    Conference poster
    The University of Auckland Library

    Rationale: Measurements of ventilation distribution using various imaging modalities have suggested that the distribution of ventilation in the supine and prone postures is less evidently gravitational than when the lung is upright, and with some studies showing little difference between ventilation distributions in the prone and supine lung. This is despite the concurrent observations of a significant gradient in tissue density when supine, and a typically smaller - or absent - tissue density gradient prone. In this study we use a computational model of lung tissue elasticity coupled to air-flow to study the relationship between posture, density distribution, and ventilation. Methods: An imaging-based geometric model of the lung and airway tree that was developed in a separate study was used here. Flow in the airways was simulated using a one-dimensional fluid dynamics model that includes flow-dependent airway resistance and coupling to tissue elasticity at the airway walls and at the acini. A finite deformation elasticity model was used to predict the effect of gravity on tissue deformation, and the non-linear elasticity of each acinar tissue unit during simulated breathing. The upright lung volume was defined from pulmonary function testing; the supine and prone volumes were assumed to be the same, and equal to the supine air volume as calculated from the subject's computed tomography imaging acquired at FRC. Tissue density and ventilation at each of the ~32,000 distributed acini in the model were averaged within iso-gravitational slices of 10 mm thickness. Results: The gradient of tissue density predicted by the model was markedly larger in supine than in upright or prone. Ratios of the maximum to minimum slice density were 1.95, 1.51, and 1.39 for supine, prone, and upright, respectively. Ventilation in the upright model increased on average towards the dependent tissue, whereas ventilation in supine and prone was decreased in the most dependent and non-dependent regions. The ratios of maximum to minimum slice ventilation were 1.09, 1.03, and 1.31 for supine, prone, and upright, respectively. Conclusions: A lack of gravitational distribution of ventilation in the supine and prone postures compared with upright is predicted on the basis of the smaller size of the horizontal lung and a shift of the dependent tissue to a less-compliant region of the sigmoidal pressure-volume curve at its lower asymptote. This is the same mechanism that results in early filling of the non-dependent tissue when inhaling from residual volume.

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  • Diabetes Management by Primary Health Care Nurses in Auckland, New Zealand

    Daly, Barbara; Arroll, B; Sheridan, N; Kenealy, T; Scragg, R (2011-11-04)

    Conference poster
    The University of Auckland Library

    Methods PHC nurses in Auckland (a 26% random sample) were asked to complete postal and telephone questionnaires (86% response rate), on education, experience, knowledge and diabetes management practice, and to log their care given to diabetes patients on a randomly selected day (n=265). Results Responses were received from 287 PHC nurses (86% response rate) comprising 210 practice nurses (PN), 49 district nurses (DN) and 28 specialist nurses (SNs). Most nurses (96%) were able to identify excess body weight as a major risk factor for type 2 diabetes and elevated blood glucose levels (BGLs) or glycosylated haemoglobin (HbA1c) (86%) for diabetes-related complications. In contrast, CV risk factors were less well identified, particularly smoking, although more by SNs (43%) than PNs (14%) and DNs (12%, p=0.0005). CV complications, especially stroke, were less well known than microvascular complications, and by significantly fewer PNs (13%) and DNs (8%) than SNs (36%, p=0.002). Stronger associations were found between nurse’s knowledge of elevated HbA1c as a risk factor for diabetes-related complications and management activities related to BGLs and medication, compared with knowledge of CV risk factors, which was not associated with assessment of blood pressure or knowledge of patient’s total cholesterol or smoking status. The median number of patients consulted on the randomly selected day was one by 38% of PNs, two by 47% of DNs and 4-5 by 57% of SNs. Overall, PNs consulted almost 60% of the patients sampled, while patients consulted by DNs were older and more likely to be European New Zealanders, tobacco uses and have diabetes-related complications and co-morbidities, while SNs consulted by Maori and Pacific patients. Conclusion: There is a need for PHC nurses to increase their knowledge of CV risk factors with more effective management required and particularly of smoking.

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  • Substrate capture mechanism provides a mode for inhibition

    Evans, Genevieve; Short, F; Castell, A; Cookson, T; Gamage, Swarnalatha; Denny, B; Baker, E; Lott, S (2011-05-11)

    Conference poster
    The University of Auckland Library

    Mycobacteria tuberculosis (Mtb), the causative agent of tuberculosis, is responsible for more death in the world today than any other bacteria. As part of the Tuberculosis Structural Genomics Consortium (TBSGC), our research group previously determined the structure of anthranilate phosphoribosyl transferase (AnPRT) from Mtb. AnPRT is the second enzyme in the tryptophan biosynthetic pathway and was identified as a potential drug target through gene knockout experiments, which resulted in a strain of Mtb that was essentially avirulent even in immunodeficient mice. AnPRT catalyses a reaction between anthranilate and phosphoribosylpyrophosphate (PRPP), and the crystal structure of Mtb-AnPRT was originally determined with and without PRPP (PDB ID: 1ZVW and 2BPQ, respectively). In silico docking was used to predict the binding motif of anthranilate, the second substrate, surprisingly predicted two sites despite a 1:1 reaction ratio with PRPP. Previously, 165 compounds were screened for inhibitory action against Mtb-AnPRT. The most potent of these compounds was co-crystallized with Mtb-AnPRT and PRPP. One compound had a bianthranilate character and the 2.0 Å resolution structure of this inhibitor bound to Mtb-AnPRT (PDB ID: 3QQS) was determined by molecular replacement using the Mtb-AnPRT structure without PRPP bound (PDB ID: 1ZVW) as a search model. Interestingly, the structure revealed multiple binding motifs for the inhibitor, two of which were consistent with the previously predicted binding motifs for anthranilate. Forty analogues of this potent Mtb-AnPRT inhibitor were subsequently assayed for activity against the enzyme, several of which showed were found to be more potent inhibitors. This new series of inhibitors were docked into the 3QQS structure, providing insights for the development of more potent inhibitors. Such techniques will continue to drive design of increasingly potent inhibitors against Mtb-AnPRT for future development of a new anti-tuberculosis agent.

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  • Potential Uses of Adipose Derived Stem Cells in Reconstructed Human Skin

    Feisst, Vaughan; Dunbar, PR (2011-01-30)

    Conference poster
    The University of Auckland Library

    Adipose derived stem cells (ASC) are multipotent adult mesenchymal stem cells with great potential for use in regenerative medicine. ASC are obtained from lipoaspirate, making them a relatively abundant and accessible source of adult stem cells. The aim of this investigation was to evaluate whether ASC can substitute dermal fibroblasts, and provide benefits for neovascularisation, in reconstructed human skin.

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  • Multi-dimensional model generalisation of human activity patterns in space and time

    Zhao, Jinfeng; Forer, Pip (2007-09-19)

    Conference poster
    The University of Auckland Library

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  • Factors Influencing the Aroma Stability of New Zealand Sauvignon blanc

    Herbst-Johnstone, Mandy; Kilmartin, PA; Nicolau, L (2009)

    Conference poster
    The University of Auckland Library

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  • Factors Influencing the Aroma Stability of New Zealand Sauvignon blanc

    Herbst, M; Nicolau, Laura; Kilmartin, Paul (2009-08)

    Conference poster
    The University of Auckland Library

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  • Stability of varietal aromas in Marlborough Sauvignon blanc wines

    Herbst, M; Kilmartin, Paul; Nicolau, Laura (2007-07)

    Conference poster
    The University of Auckland Library

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  • Factors Influencing the Aroma Stability of Sauvignon blanc Wines

    Herbst-Johnstone, Mandy; Nicolau, L; Kilmartin, Paul (2010-07)

    Conference poster
    The University of Auckland Library

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  • The skeletal effects of the tyrosine kinase inhibitor nilotinib

    O'Sullivan, Susannah; Lin, Jian; Watson, M; Callon, K; Tong, PC; Naot, Dorit; Horne, Anne; Aati, O; Porteous, F; Gamble, G; Cornish, Jillian; Browett, Peter; Grey, Andrew (2011-09)

    Conference poster
    The University of Auckland Library

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  • Identification of a lead hypoxia-activated irreversible pan-HER inhibitor SN32807 (PR509) by pharmacokinetic and anti-tumor efficacy screening in an erlotinib-resistant xenograft model

    Jaiswal, Jagdish; Lu, Guo-Liang; Jamieson, S; Lee, Ho; Abbattista, Maria; Anderson, BF; Ashoorzadeh, Amir; Denny, William; Doñate, F; Hsu, HL; Maroz, A; Pruijn, A; Puryer, M; Thompson, Aaron; Wilson, William; Smaill, Jeffrey; Patterson, Adam (2011-10-23)

    Conference poster
    The University of Auckland Library

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  • A new implantable transmitter for simultaneous recording of sympathetic nerve activity and blood pressure

    Lim, M; McCormick, John; Kirton, RS; Budgett, David; Kondo, Masahiro; Pallas, Wayne; Guild, Sarah-Jane; Barrett, Carolyn; Malpas, Simon (2008-04-05)

    Conference poster
    The University of Auckland Library

    •Over activity of the sympathetic nervous system has been implicated in a number of cardiovascular diseases. •The direct recordings of sympathetic nerve activity (SNA) in conscious animals in combination with blood pressure provides ideal platform for exploring the role of SNA in the disease process. •While a telemetry system has been developed to enable recording of SNA it has required the implantation of a separate transmitter to record blood pressure. •We have now developed wireless implantable transmitters capable of simultaneously recording arterial blood pressure and sympathetic nerve activity.

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  • Doped Diamond-Like Carbon (DLC) coated surfaces to reduce fouling from milk

    Patel, Jaiminkumar; Bansal, B; Jones, MI; Hyland, M (2010-11-09)

    Conference poster
    The University of Auckland Library

    In the dairy industry, fouling of processing surfaces is a common and unresolved problem. Surface modification, for example through the application of a surface coating, can alter the surface properties of a material, and may be a potential way to reduce fouling. Typical dairy plant stainless steel surfaces were modified by the deposition of doped Diamond-Like Carbon (DLC) films with varying concentration of doped elements. These modified surfaces were studied for their fouling behavior with milk at both laboratory and pilot scale. None of the doped DLC modified surfaces investigated in the study presented benefits in fouling reduction as compared to unmodified surface.

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  • Three-Dimensional Structural Characterization of Tissue Engineered and Native Ovine Pulmonary Valves

    Eckert, Chad; Gerneke, Dane; LeGrice, IJ; Gottlieb, David; Mayer, JE; Sacks, MS (2009-04)

    Conference poster
    The University of Auckland Library

    OBJECTIVES: Efforts in tissue-engineered heart valves (TEHV) have shown increasingly equivalent mechanical/structural properties compared to native valves, though a literature gap exists regarding detailed structural information. This work was performed to provide such data of implanted TEHV, the native pulmonary valve (PV), and pre-implant scaffold to better understand developing TEHV. METHODS: Dynamically-cultured in vivo samples (“pre-implant”) and ovine TEHV PV in vitro samples (“explant”) were produced based on previous techniques; ovine PVs were excised. Samples were stained with picrosirius red and resinmounted. Using extended-volume scanning laser confocal microscopy (EV-SLCM), 1.5 x 1.5 x 0.4 mm full-thickness samples were imaged at 1 pixel/μm in 1 μm Z-direction steps. Custom software was used to process and visualize samples. Collagen, cell nuclei, and scaffold volume fractions were quantified; scaffold fiber trajectory and length were tracked using custom software. RESULTS: In a scaffold representative volume (90 μm thick), 104 fibers were tracked with a mean fiber length of 137.94 μm 55.4 μm (Fig.1). A comparison between pre-implant and explant samples showed collagen volume fraction increasing from 76.6% to 85.9%, with nuclei and scaffold decreasing from 2.8% to 0.5% and from 5.9% to 0.8%, respectively. With the native collagen volume fraction measured at 70%, pre-implant and explant samples showed an increase in collagen. CONCLUSIONS: This work captured important differences between in vivo/in vitro TEHV constituents; it is the first known work to utilize EV-SLCM on TEHV. A comparison to the native valve showed structural differences that could impact longterm functionality and improve design.

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  • The use of whole community bacterial indicators to monitor ecological health, function and variability within stream biofilms

    Lear, Gavin; Boothroyd, IK; Lewis, Gillian (2009-08-30)

    Conference poster
    The University of Auckland Library

    This study describes the extent of variability in biofilm bacterial community structure across a broad range of spatial and temporal scales and assesses whether this may be used as an indicator of stream ecological health and function. A community DNA fingerprinting technique (Automated Ribosomal Intergenic Spacer Analysis - ARISA) was used to examine the structure of bacterial communities within freshwater stream biofilms. When compared with macrobenthic invertebrate community assemblages using multi-dimensional scaling techniques, similar broad-scale trends in population structure were revealed between organisms at these different trophic levels. For both communities, spatial variability in community structure was greater between streams than within each site, or compared to temporal variability measured over 1 year. Distance-based redundancy analysis of both bacterial ARISA and macroinvertebrate data estimated that the largest cause of variation in community structure was due to differences in catchment land-use, rather than any single water quality parameter (e.g. ph or ammoniacal nitrogen). Multidimensional scaling of ARISA data also revealed significant differences in community structure between urban, and less impacted stream sites, providing evidence that whole-bacterial communities could be used as an indicator of freshwater ecological health, analogous to the way that macroinvertebrate communities have been used for many years. In conclusion, we propose the analysis of whole bacterial communities as a cost-effective, high throughput alternative indicator of freshwater ecological health.

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  • Ciliate Diversity in Stream Biofilms revealed by group-specific PCR primers.

    Dopheide, Andrew; Lear, Gavin; Stott, R; Lewis, Gillian (2008-08-17)

    Conference poster
    The University of Auckland Library

    The ciliates are a diverse protozoan phylum, thought to be of considerable ecological importance in stream ecosystems, including organisms which are abundant and important consumers of bacteria, algae and other protozoa. Understanding of ciliate diversity and ecology is limited, however, particularly in benthic habitats such as stream biofilms. In this study, phylum-specific PCR primers were used in combination with cloning, sequencing and terminal restriction fragment length polymorphism (T-RFLP) analysis to investigate ciliate communities in stream biofilms.

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  • Human Adenovirus ecology in environmental waters in New Zealand

    Dong, Yimin; Lewis, Gillian (2008-08-17)

    Conference poster
    The University of Auckland Library

    A major New Zealand study of pathogen occurrence in surface freshwaters identified occurrence of human adenovirus in 30% of sites and samples by qualitative PCR based methods. The source or nature of these viruses was not clear from the study and raises important questions in both viral ecology and human health protection. The aim of this study was to begin to unravel these questions by (i) development of specific quantitative analysis methods for adenoviruses in water and (ii) to target identifiable groups of adenovirus associated with human respiratory or gastrointestinal infections. These quantitative group specific real time PCR methods were tested in drinking water, recreational water, river water and wastewater. Adenovirus was detected in all primary wastewater samples tested (n=10) at high genome copy number (1.87 x104 to 4.6 x106 per litre) and in 33% (n=15) of the river water and 11% (n=27) of the treated drinking water samples. In addition, adenovirus was detected in 5 of the 6 estuarine recreational water samples (17 to 1190 virus genome copies per litre). DNA sequence analysis suggested that human adenovirus group C (respiratory infection associated) were most commonly associated with river, recreational and drinking water. Group F adenovirus (gastroenteritis associated viruses) were found to dominate in most wastewater (5 - 100 % total adenovirus) but were not detected in surface waters. This study suggests that the ecology of specific groups or types of adenovirus is sufficiently different, external to the host, to have important implications for human health risk assessment.

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  • Effect of light regimes on the utilisation of an exogenous carbon source by freshwater biofilm communities

    Lear, Gavin; Lewis, Gillian (2007-06-23)

    Conference poster
    The University of Auckland Library

    Biofilms are a major source of ‘in stream’ primary production, exhibiting high population density, and being an important source of carbon for microbial heterotrophs. Changing patterns of land-use within freshwater catchment areas may greatly impact on stream biofilm microbial community structure, which in turn may influence the speed and extent with which full ecosystem recovery may occur. This study reports how freshwater biofilm communities respond to additions of acetate, used as a proxy for organic matter, the primary source of carbon within shaded forests and headwater streams. The use of [ 13C] acetate and subsequent isolation of 13C-labelled nucleic acids from the metabolically active fraction of the bacterial community enabled substrate assimilating organisms to be identified. In addition, biofilms were exposed to varied levels of incident light to assess the relative contribution of phototrophic and heterotrophic nutrition.

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  • Delayed Cerebral Post-arteriole Dilation is Consistent with Observations at Multiple Spatial and Temporal Scales: Evidence from Mathematical Modelling

    Barrett, MJP; Tawhai, MH; Suresh, Vinod (2011-05-25)

    Conference poster
    The University of Auckland Library

    Background and aims: Observations from different neurovascular imaging modalities provide conflicting evidence about the presence and/or extent of volume changes in post-arteriole blood vessels. At the level of individual vessels, two-photon imaging during functional activation shows a rapid increase in arteriolar diameter, but little or no increase in capillaries or venules 1 . In contrast, 'bulk' measurements of flow-volume relationships show large increases in arterial volume 2 , and smaller - but still significant - increases in venous volume 3 . Here, we reconcile these competing observations using a dynamic, biophysically based mathematical model of the hemodynamic response. Methods: We use the widely known Windkessel model that represents blood flow as analogous to electrical current, and networks of blood vessels as analogous to electrical resistances and capacitances. The model also includes a novel description of vascular compliance, viscoelastic effects, and stimulus-driven vasodilation. Experimental observations at progressively more detailed scales are used to constrain and validate the model, following a 'top down' approach. In addition, we test the assumption that post-arteriole vessels do not dilate, and use the model to predict observations at progressively more aggregated scales, following a 'bottom up' approach. Results: Model predictions of the total, arterial, and venous steady state flow-volume relationships agree well with experimental observations, as do predictions of transient changes in flow and volume during functional activation. The model also predicts rapid arteriole dilation during activation. Interestingly, this is accompanied by slow increases in capillary and venule diameter that - for brief stimulation - are near indistinguishable from baseline noise. When assuming no dilation of capillaries or venules, there are only minor differences between the model predictions at the single vessel scale. However, predictions at more aggregated scales are qualitatively and quantitatively different from experimental observations. Conclusions: The model presented here is able to reproduce the main features of experimental observations over a range of spatial and temporal scales. These results suggest that arterial dilation represents the majority of regional cerebral blood volume increases during functional activation, especially during brief stimulation. However, passive dilation in capillaries and venules may be increasingly significant during extended stimulation. This is an important consideration when interpreting or comparing results from neurovascular imaging modalities, such as optical methods and magnetic resonance imaging.

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  • An examination of the extent of adult neurogenesis in the carpet shark (Cephaloscyllium isabellum)

    Finger, JSH; Kubke, Maria; Wild, JM; Montgomery, JC (2008)

    Conference poster
    The University of Auckland Library

    Following Altman’s and Kirsche’s challenge to the dogma that no new neurons could be produced during adulthood in the 1960’s, adult neurogenesis was shown in most vertebrate lineages. From a phylogenetic point of view, adult neurogenesis is not an uncommon event, having been demonstrated in reptiles and birds, amphibians, bony fi shes and mammals. At present, however, adult neurogenesis has not been examined in cartilagineous fi shes, the stem line of vertebrates. Sharks are an ideal group in which to study the extent of adult neurogenesis for several reasons: (i) they exhibit continuous body growth throughout life; (ii) in the stingray the number of peripheral axons and neurons continues to increase into adult life; and (iii) in adult gray reef sharks the number of inner ear hair cells also continues to increase. We have begun to evaluate the extent of adult neurogenesis in the carpet shark (Cephaloscyllium isabellum). A specimen of C isabellum was injected i.p. with 230 mg/kg of BrdU, anaesthetised and perfused after 2 hrs. The brain was cryoprotected and cut at 40 μm, and processed following standard immunocytochemical techniques. BrdU was found in a small number of nuclei in close proximity to the ventricular surface, in a similar position than occasional cells labelled with an antibody aginst β-tubuline (III). Some BrdU labelled nuclei were also found throughout the brain that were not stained with our neuronal marker. These preliminary data suggest that adult neurogenesis occurs in sharks and that like in bony fi shes, but unlike birds and mammals, it may also occur in non-telencephalic areas. If widespread adult neurogenesis can be unequivocally demonstrated in sharks, it would indicate that it represents the primitive condition. This therefore raises the question of what modifi cations in brain evolution of modern vertebrate lineages led to the restriction of this ability to specifi c forebrain areas.

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