ORCID Profile
0000-0003-2268-1452
Current Organisation
Murdoch University
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Publisher: Wiley
Date: 12-02-2020
DOI: 10.1111/EVJ.13216
Abstract: Electrical impedance tomography (EIT) generates thoracic impedance images of the lungs and has been used to assess ventilation in horses. This technique may have application in the detection of changes in airflow associated with equine asthma. The objective was to determine if histamine-induced airflow changes observed with flowmetric plethysmography (Δflow) could also be explained using global and regional respiratory gas flow signals calculated from EIT signals. Experimental in vivo study. Six horses, sedated using detomidine were fitted with a thoracic EIT belt and flowmetric plethysmography hardware. Saline (baseline = BL) and increasing concentrations of histamine (C1-4) were nebulised into the face mask until a change in breathing pattern was clinically confirmed and Δflow increased greater or equal to 50%. After nebulisation Δflow and EIT images were recorded over 3 minutes and peak global inspiratory (InF Consistent with histamine-provoked increases in Δflow, the global flow indices increased significantly. A significant increase in regional inspiratory flow was seen in the right and left ventral lung and dorsal right lung. Multiple regression revealed that the variance in ExF Low number of horses and horses were healthy. Standardised changes in airflow during histamine challenge could be detected using EIT gas flow variables.
Publisher: Wiley
Date: 03-06-2018
DOI: 10.1111/AVJ.12716
Abstract: The purpose of this article is to provide a review of the current knowledge and opinions about the epidemiology, clinical findings (including sequelae), diagnosis, treatment and monitoring of equine pituitary pars intermedia dysfunction, particularly in the Australian context. This information and the recommendations provided will assist practitioners in making informed decisions regarding the diagnosis and management of this disorder.
Publisher: Wiley
Date: 11-05-2021
DOI: 10.1111/JVIM.16152
Abstract: Electrical impedance tomography (EIT) generates images of the lungs based on impedance change and was able to detect changes in airflow after histamine challenge in horses. To confirm that EIT can detect histamine‐provoked changes in airflow and subsequent drug‐induced bronchodilatation. Novel EIT flow variables were developed and examined for changes in airflow. Bronchoconstriction was induced using stepwise histamine bronchoprovocation in 17 healthy sedated horses. The EIT variables were recorded at baseline, after saline nebulization (control), at the histamine concentration causing bronchoconstriction (C max ) and 2 and 10 minutes after albuterol (salbutamol) administration. Peak global inspiratory (PIF EIT ) and peak expiratory EIT (PEF EIT ) flow, slope of the global expiratory flow‐volume curve (FV slope ), steepest FV slope over all pixels in the lung field, total impedance change (surrogate for tidal volume VT EIT ) and intercept on the expiratory FV curve normalized to VT EIT (FV intercept /VT EIT ) were indexed to baseline and analyzed for a difference from the control, at C max , 2 and 10 minutes after albuterol. Multiple linear regression explored the explanation of the variance of Δflow, a validated variable to evaluate bronchoconstriction using all EIT variables. At C max , PIF EIT , PEF EIT , and FV slope significantly increased whereas FV intercept /VT decreased. All variables returned to baseline 10 minutes after albuterol. The VT EIT did not change. Multivariable investigation suggested 51% of Δflow variance was explained by a combination of PIF EIT and PEF EIT . Changes in airflow during histamine challenge and subsequent albuterol administration could be detected by various EIT flow volume variables.
Publisher: Cold Spring Harbor Laboratory
Date: 17-07-2021
DOI: 10.1101/2021.07.16.452724
Abstract: A novel Hendra virus (HeV) variant, not detected by routine testing, was identified and isolated from a Queensland horse that suffered acute, fatal disease consistent with HeV infection. Whole genome sequencing and phylogenetic analysis demonstrated the variant to have ~83% nucleotide identity to the prototype HeV strain. An updated RT-qPCR assay was designed for routine HeV surveillance. In silico and in vitro comparison of the receptor-binding protein with prototypic HeV showed that the human monoclonal antibody m102.4 used for post-exposure prophylaxis, as well as the current equine vaccine, should be effective against this variant. Genetic similarity of this virus to sequences detected from grey-headed flying-foxes suggests the variant circulates at-least in this species. Studies determining infection kinetics, pathogenicity, reservoir-species associations, viral–host co-evolution and spillover dynamics for this virus are urgently needed. Surveillance and biosecurity practices should be updated to appreciate HeV spillover risk across all regions frequented by flying foxes.
Publisher: Wiley
Date: 29-06-2017
DOI: 10.1111/JVIM.14782
Publisher: Elsevier BV
Date: 07-2021
Publisher: Wiley
Date: 08-07-2019
DOI: 10.1111/AVJ.12861
Abstract: To investigate the relationship between bronchoalveolar lavage fluid cytology, particularly mast cells, and airway hyper-reactivity in athletic horses presented for poor performance that included a respiratory tract evaluation in two disparate locations in Australia. Multi-centre, retrospective and prospective cross-sectional study METHODS: Eighty four adult horses underwent both pulmonary function testing and histamine bronchoprovocation with a commercial flowmetric plethysmography system. A bronchoalveolar lavage was performed four to twelve hours later. Bronchoalveolar lavage fluid cytology was categorised using two differing classification systems to define mild equine asthma. Statistical analysis was used to assess associations between bronchoalveolar lavage fluid relative inflammatory cell percentages, and airway hyper-reactivity and their associated categorisations. Sixty four percent (54/84) of horses displayed airway hyper-reactivity, as defined by PC In the Australian context, recently revised increased bronchoalveolar lavage fluid cytology relative cell percentage cut offs appear appropriate for sole mast cell responses. The historical lower cut offs appear to be appropriate for mixed inflammatory cell responses.
Publisher: Wiley
Date: 04-08-2021
DOI: 10.1111/JVIM.16227
Abstract: Left‐sided cardiac volume overload (LCVO) can cause fluid accumulation in lung tissue changing the distribution of ventilation, which can be evaluated by electrical impedance tomography (EIT). To describe and compare EIT variables in horses with naturally occurring compensated and decompensated LCVO and compare them to a healthy cohort. Fourteen adult horses, including university teaching horses and clinical cases (healthy: 8 LCVO: 4 compensated, 2 decompensated). In this prospective cohort study, EIT was used in standing, unsedated horses and analyzed for conventional variables, ventilated right (VA R ) and left (VA L ) lung area, linear‐plane distribution variables (avg‐max VΔZ Line , VΔZ Line ), global peak flows, inhomogeneity factor, and estimated tidal volume. Horses with decompensated LCVO were assessed before and after administration of furosemide. Variables for healthy and LCVO‐affected horses were compared using a Mann‐Whitney test or unpaired t ‐test and observations from compensated and decompensated horses are reported. Compared to the healthy horses, the LCVO cohort had significantly less VA L (mean difference 3.02 95% confidence interval .77‐5.2 P = .02), more VA R (−1.13 −2.18 to −.08 P = .04), smaller avg‐max VΔZ L Line (2.54 1.07‐4.00 P = .003) and VΔZ L Line (median difference 5.40 1.71‐9.09 P = .01). Observation of EIT alterations were reflected by clinical signs in horses with decompensated LCVO and after administration of furosemide. EIT measurements of ventilation distribution showed less ventilation in the left lung of horses with LCVO and might be useful as an objective assessment of the ventilation effects of cardiogenic pulmonary disease in horses.
Publisher: Wiley
Date: 26-07-2018
DOI: 10.1111/AVJ.12721
Abstract: To characterise the relationship between bronchoalveolar lavage fluid (BALF) cytology and pulmonary function testing with histamine bronchoprovocation (HBP) methods in a population of clinically normal horses. Cross-sectional study METHODS: Clinically normal adult horses (n = 33) underwent pulmonary function testing and HBP with a commercial flowmetric plethysmography system. BAL was performed 1-5 days later. Statistical analysis was used to assess associations between BALF cell concentration, relative inflammatory cell percentages and categorisation, and airway hyper-reactivity (AHR). AHR (PC A direct association between cytological evidence of airway inflammation and AHR was not identified in this population of clinically normal horses. Determining the presence and measuring inflammatory cell mediators in BALF may more accurately reflect AHR. In addition, normal values for cell proportions in BALF may vary between different populations of horses and more appropriate regional reference ranges should be established.
Publisher: Wiley
Date: 12-05-2023
DOI: 10.1111/EVE.13811
Abstract: The natural progression of equine glandular gastric disease (EGGD) in the absence of treatment has not yet been described in the literature, nor has the prevalence in a teaching herd population been reported. The aims of this study were to determine the prevalence of disease in a teaching population over the study period (2019–2021) and to observe the changes over time in disease severity of naturally occurring diseases (not experimentally induced) without medical intervention. Twenty‐one horses underwent an initial gastroscopy and a repeat gastroscopy between 14 and 731 days later. Gastroscopy data were graded quantitatively and described qualitatively. Prevalence and 95% confidence intervals (CI) were calculated. The changes over time were determined by comparing initial and repeat gastroscopies. The prevalence from initial, repeat and total number of gastroscopies was 62% (95% CI: 40.8–79.3), 71% (95% CI: 50.0–86.2) and 67% (95% CI: 51.6–79), respectively. The changes over time included worsening of disease in 29% of horses (95% CI: 13.8–50.0), improvement of disease to a lower grade in 24% (95% CI: 10.6–45.1), no change in grade in 38% (95% CI: 20.8–59.1), and complete resolution of disease to grade 0 in 10% (95% CI: 2.7–28.9). Limitations included a maximum of two gastroscopies per horse given COVID‐19 restrictions on data collection, and highly varied interval times between initial and repeat gastroscopies. In conclusion, there is a high prevalence of disease in this teaching herd. The changes over time in naturally occurring diseases without medical intervention might include worsening, improvement, no change or resolution of disease.
No related grants have been discovered for Cristy Secombe.