115 research outputs found
High-resolution mucociliary transport measurement in live excised large animal trachea using synchrotron X-ray imaging
Get PDFBackground: The Australian Synchrotron Imaging and Medical Beamline (IMBL) was designed as the world's widest synchrotron X-ray beam, enabling both clinical imaging and therapeutic applications for humans as well as the imaging of large animal models. Our group is developing methods for imaging the airways of newly developed CF animal models that display human-like lung disease, such as the CF pig, and we expect that the IMBL can be utilised to image airways in animals of this size. Methods: This study utilised samples of excised tracheal tissue to assess the feasibility, logistics and protocols required for airway imaging in large animal models such as pigs and sheep at the IMBL. We designed an image processing algorithm to automatically track and quantify the tracheal mucociliary transport (MCT) behaviour of 103 μm diameter high refractive index (HRI) glass bead marker particles deposited onto the surface of freshly-excised normal sheep and pig tracheae, and assessed the effects of airway rehydrating aerosols. Results: We successfully accessed and used scavenged tracheal tissue, identified the minimum bead size that is visible using our chosen imaging setup, verified that MCT could be visualised, and that our automated tracking algorithm could quantify particle motion. The imaging sequences show particles propelled by cilia, against gravity, up the airway surface, within a well-defined range of clearance speeds and with examples of 'clumping' behaviour that is consistent with the in vivo capture and mucus-driven transport of particles. Conclusion: This study demonstrated that the wide beam at the IMBL is suitable for imaging MCT in ex vivo tissue samples. We are now transitioning to in vivo imaging of MCT in live pigs, utilising higher X-ray energies and shorter exposures to minimise motion blur.Martin Donnelley, Kaye S. Morgan, Maged Awadalla, Nigel R. Farrow, Chris Hall and David W. Parson
Cost utility analysis of intramedullary nailing and skeletal traction treatment for patients with femoral shaft fractures in Malawi
Get PDFBackground and purpose — In Malawi, both skeletal traction (ST) and intramedullary nailing (IMN) are used in the treatment of femoral shaft fractures, ST being the mainstay treatment. Previous studies have found that IMN has improved outcomes and is less expensive than ST. However, no cost-effectiveness analyses have yet compared IMN and ST in Malawi. We report the results of a cost-utility analysis (CUA) comparing treatment using either IMN or ST.
Patients and methods — This was an economic evaluation study, where a CUA was done using a decision-tree model from the government healthcare payer and societal perspectives with an 1-year time horizon. We obtained EQ-5D-3L utility scores and probabilities from a prospective observational study assessing quality of life and function in 187 adult patients with femoral shaft fractures treated with either IMN or ST. The patients were followed up at 6 weeks, and 3, 6, and 12 months post-injury. Quality adjusted life years (QALYs) were calculated from utility scores using the area under the curve method. Direct treatment costs were obtained from a prospective micro costing study. Indirect costs included patient lost productivity, patient transportation, meals, and childcare costs associated with hospital stay and follow-up visits. Multiple sensitivity analyses assessed model uncertainty.
Results — Total treatment costs were higher for ST (1,122). QALYs were lower for ST than IMN, 0.71 (95% confidence interval [CI] 0.66–0.76) and 0.77 (CI 0.71–0.82) respectively. Based on lower cost and higher utility, IMN was the dominant strategy. IMN remained dominant in 94% of simulations. IMN would be less cost-effective than ST at a total procedure cost exceeding 1,035 from the societal perspective.
Interpretation — IMN was cost saving and more effective than ST in the treatment of adult femoral shaft fractures in Malawi, and may be an efficient use of limited healthcare resources.publishedVersio
Transduction of ferret airway epithelia using a pre-treatment and lentiviral gene vector
Get PDFBACKGROUND: The safety and efficiency of gene therapies for cystic fibrosis (CF) need to be assessed in pre-clinical models. Using the normal ferret, this study sought to determine whether ferret airway epithelia could be transduced with a lysophosphatidylcholine (LPC) pre-treatment followed by a VSV-G pseudotyped HIV-1 based lentiviral (LV) vector, in preparation for future studies in CF ferrets. METHODS: Six normal ferrets (7 -8 weeks old) were treated with a 150 μL LPC pre-treatment, followed one hour later by a 500 μL LV vector dose containing the LacZ transgene. LacZ gene expression in the conducting airways and lung was assessed by X-gal staining after 7 days. The presence of transduction in the lung, as well as off-target transduction in the liver, spleen and gonads, were assessed by qPCR. The levels of LV vector p24 protein bio-distribution in blood sera were assessed by ELISA at 0, 1, 3, 5 and 7 days. RESULTS: The dosing protocol was well tolerated. LacZ gene expression was observed en face in the trachea of all animals. Histology showed that ciliated and basal cells were transduced in the trachea, with rare LacZ transduced single cells noted in lung. p24 levels was not detectable in the sera of 5 of the 6 animals. The LacZ gene was not detected in the lung tissue and no off-target transduction was detected by qPCR. CONCLUSIONS: This study shows that ferret airway epithelia are transducible using our unique two-step pre-treatment and LV vector dosing protocol. We have identified a number of unusual anatomical factors that are likely to influence the level of transduction that can be achieved in ferret airways. The ability to transduce ferret airway epithelium is a promising step towards therapeutic LV-CFTR testing in a CF ferret model.Patricia Cmielewski, Nigel Farrow, Martin Donnelley, Chantelle McIntyre, Jahan Penny-Dimri, Tim Kuchel and David Parson
Weak and Electromagnetic Nuclear Decay Signatures for Neutrino Reactions in SuperKamiokande
Full text linkWe suggest the study of events in the SuperKamiokande neutrino data due to
charged- and neutral-current neutrino reactions followed by weak and/or
electromagnetic decays of struck nuclei and fragments thereof. This study could
improve the prospects of obtaining evidence for production from oscillations and could augment the data sample used to disfavor
oscillations.Comment: 7 pages, latex, to appear in Phys. Rev. Let
Repeat or single-dose lentiviral vector administration to mouse lungs? It’s all about the timing
Get PDFLentiviral vectors are attractive delivery vehicles for cystic fibrosis gene therapy owing to their low immunogenicity and ability to integrate into the host cell genome, thereby producing long-term, stable gene expression. Nonetheless, repeat dosing may be required to increase initial expression levels, and/or boost levels when they wane. The primary aim of this study was to determine if repeat dosing of a VSV-G pseudotyped LV vector delivered into mouse lungs is more effective than a single dose. C57Bl/6 mouse lungs were conditioned with lysophosphatidylcholine, followed one-hour later by a LV vector carrying the luciferase reporter gene, using six different short-term (≤1 wk) and long-term (>1 wk) dosing schedules. Luciferase expression was quantified using bioluminescence imaging over 12 months. Most dosing schedules produced detectable bioluminescence over the 12-month period, but the shorter intervals (≤1 wk) produced higher levels of flux than the longest interval (five doses at least 1-month apart). Ex vivo lung analysis at 12 months showed that the estimated mean flux for the group that received two doses 1-week apart was significantly greater than the single dose group and the two groups that received doses over a period greater than 1-week. These results suggest that early consecutive multiple doses are more effective at improving gene expression in mouse lungs at 12 months, than longer repeat dosing intervals.Martin Donnelley, Patricia Cmielewski, Emma Knight, Chantelle Carpentieri, Alexandra McCarron, Nathan Rout-Pitt, David Parsons, and Nigel Farro
Quantification of heterogeneity in lung disease with image-based pulmonary function testing
Get PDFPublished: 27 July 2016Computed tomography (CT) and spirometry are the mainstays of clinical pulmonary assessment. Spirometry is effort dependent and only provides a single global measure that is insensitive for regional disease, and as such, poor for capturing the early onset of lung disease, especially patchy disease such as cystic fibrosis lung disease. CT sensitively measures change in structure associated with advanced lung disease. However, obstructions in the peripheral airways and early onset of lung stiffening are often difficult to detect. Furthermore, CT imaging poses a radiation risk, particularly for young children, and dose reduction tends to result in reduced resolution. Here, we apply a series of lung tissue motion analyses, to achieve regional pulmonary function assessment in β-ENaC-overexpressing mice, a well-established model of lung disease. The expiratory time constants of regional airflows in the segmented airway tree were quantified as a measure of regional lung function. Our results showed marked heterogeneous lung function in β-ENaC-Tg mice compared to wild-type littermate controls; identified locations of airway obstruction, and quantified regions of bimodal airway resistance demonstrating lung compensation. These results demonstrate the applicability of regional lung function derived from lung motion as an effective alternative respiratory diagnostic tool.Charlene S. Stahr, Chaminda R. Samarage, Martin Donnelley, Nigel Farrow, Kaye S. Morgan, Graeme Zosky, Richard C. Boucher, Karen K. W. Siu, Marcus A. Mall, David W. Parsons, Stephen Dubsky and Andreas Foura
Synchrotron phase-contrast X-ray imaging reveals fluid dosing dynamics for gene transfer into mouse airways
Get PDFAlthough airway gene transfer research in mouse models relies on bolus fluid dosing into the nose or trachea, the dynamics and immediate fate of delivered gene transfer agents are poorly understood. In particular, this is because there are no in vivo methods able to accurately visualize the movement of fluid in small airways of intact animals. Using synchrotron phase-contrast X-ray imaging, we show that the fate of surrogate fluid doses delivered into live mouse airways can now be accurately and non-invasively monitored with high spatial and temporal resolution. This new imaging approach can help explain the non-homogenous distributions of gene expression observed in nasal airway gene transfer studies, suggests that substantial dose losses may occur at deliver into mouse trachea via immediate retrograde fluid motion and shows the influence of the speed of bolus delivery on the relative targeting of conducting and deeper lung airways. These findings provide insight into some of the factors that can influence gene expression in vivo, and this method provides a new approach to documenting and analyzing dose delivery in small-animal models.M Donnelley, KKW Siu, RA Jamison and DW Parson
Non-invasive airway health assessment: Synchrotron imaging reveals effects of rehydrating treatments on mucociliary transit in-vivo
Get PDFTo determine the efficacy of potential cystic fibrosis (CF) therapies we have developed a novel mucociliary transit (MCT) measurement that uses synchrotron phase contrast X-ray imaging (PCXI) to non-invasively measure the transit rate of individual micron-sized particles deposited into the airways of live mice. The aim of this study was to image changes in MCT produced by a rehydrating treatment based on hypertonic saline (HS), a current CF clinical treatment. Live mice received HS containing a long acting epithelial sodium channel blocker (P308); isotonic saline; or no treatment, using a nebuliser integrated within a small-animal ventilator circuit. Marker particle motion was tracked for 20 minutes using PCXI. There were statistically significant increases in MCT in the isotonic and HS-P308 groups. The ability to quantify in vivo changes in MCT may have utility in pre-clinical research studies designed to bring new genetic and pharmaceutical treatments for respiratory diseases into clinical trials
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