Publications by authors named "Beth McDonald"

5 Publications

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A study into the fatty acid content of selected veterinary diets, supplements and fish oil capsules in Australia.

Vet Dermatol 2021 Jun 15;32(3):256-e69. Epub 2021 Mar 15.

The University of Sydney Veterinary Teaching Hospital, Sydney, NSW, Australia.

Background: Dogs with cutaneous diseases often receive supplementation with omega-3 (n-3) and omega-6 (n-6) essential fatty acids (FA), either through their diet or the use of an oral supplement. Labelling on these products is not always clear, especially regarding the total and relative amounts of FA.

Objectives: To provide clinicians with a breakdown of the FA content of selected veterinary diets, supplements and fish oil capsules so that the daily dose of supplementation can be calculated more easily. Repeated measurements of FA content over time demonstrate whether FA content changes temporally.

Methods And Materials: Eight veterinary diets, four veterinary oral FA supplements and four fish oil supplements were analysed for FA content by gas chromatography at days 0, 28 and 56.

Results: The n-6:n-3 ratio varied among the supplement types with the food samples having higher ratios than the liquid supplements and fish oil capsules. The composition of n-3 FA differed between products with some having higher concentrations of the less active n-3 FA alpha-linolenic acid than eicosapentaenoic acid and docosahexaenoic acid. No decreases in FA content over time were detected.

Conclusions And Clinical Relevance: The results of this study provide the reader with a means to calculate the FA concentrations that their patient is receiving for each product tested, as well as allowing them to compare products for their differences in n-6:n-3 ratios and relative amounts of individual FA molecules. The FA concentrations did not change significantly over 56 days.
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June 2021

Exploring the use of essential fatty acids in veterinary dermatology.

Vet Rec 2020 Sep 5;187(5):190. Epub 2019 Nov 5.

The Veterinary Teaching Hospital, University of Sydney, Sydney, New South Wales, Australia.

Background: The aim of the study was to discover the extent of use of essential fatty acids (EFAs) in veterinary practice, conditions used in, preparation of EFA supplement used and rationale for their use and to investigate the awareness of the oxidation of some commercial fish oil supplement preparations.

Methods: A web-based questionnaire was distributed via email to a dermatology list server and posted to veterinary Facebook groups with questions relating to the use of EFAs, supplement choice, conditions used in, the level of importance of various factors regarding their use and awareness of their oxidation.

Results: There were 309 responses from 32 countries. EFA supplements were used by 92.2 per cent of respondents. The most commonly used preparation of EFA supplementation was veterinary oral supplements (75.1 per cent), followed by veterinary diets (14.4 per cent), shop bought fish oil supplements (7.7 per cent), enhancing the diet with oily fish (2.5 per cent) and finally using a commercial pet food (0.3 per cent). Only 46.3 per cent of respondents who used them were aware of the oxidation of EFAs. Veterinary oral supplements were perceived to be the best preserved, followed by veterinary diets and lastly commercial fish oil supplements.

Conclusion: A large number of respondents advised the use of EFAs for veterinary dermatological conditions but less than 50 per cent were aware of the potential for EFAs to oxidise.
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September 2020

Consequences and Management of Canine Brachycephaly in Veterinary Practice: Perspectives from Australian Veterinarians and Veterinary Specialists.

Animals (Basel) 2018 Dec 21;9(1). Epub 2018 Dec 21.

Sydney School of Veterinary Science, Faculty of Science, University of Sydney, Camperdown, NSW 2006, Australia.

This article, written by veterinarians whose caseloads include brachycephalic dogs, argues that there is now widespread evidence documenting a link between extreme brachycephalic phenotypes and chronic disease, which compromises canine welfare. This paper is divided into nine sections exploring the breadth of the impact of brachycephaly on the incidence of disease, as indicated by pet insurance claims data from an Australian pet insurance provider, the stabilization of respiratory distress associated with brachycephalic obstructive airway syndrome (BOAS), challenges associated with sedation and the anaesthesia of patients with BOAS; effects of brachycephaly on the brain and associated neurological conditions, dermatological conditions associated with brachycephalic breeds, and other conditions, including ophthalmic and orthopedic conditions, and behavioural consequences of brachycephaly. In the light of this information, we discuss the ethical challenges that are associated with brachycephalic breeds, and the role of the veterinarian. In summary, dogs with BOAS do not enjoy freedom from discomfort, nor freedom from pain, injury, and disease, and they do not enjoy the freedom to express normal behaviour. According to both deontological and utilitarian ethical frameworks, the breeding of dogs with BOAS cannot be justified, and further, cannot be recommended, and indeed, should be discouraged by veterinarians.
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December 2018

Vigilin interacts with signal peptide peptidase.

Proteome Sci 2012 May 18;10(1):33. Epub 2012 May 18.

Cambridge Institute for Medical Research, Department of Clinical Neurosciences, University of Cambridge, Addenbrooke's Hospital, Hills Road, England, Cambridge, CB2 0XY, United Kingdom.

Background: Signal peptide peptidase (SPP), a member of the presenilin-like intra-membrane cleaving aspartyl protease family, migrates on Blue Native (BN) gels as 100 kDa, 200 kDa and 450 kDa species. SPP has recently been implicated in other non-proteolytic functions such as retro-translocation of MHC Class I molecules and binding of misfolded proteins in the endoplasmic reticulum (ER). These high molecular weight SPP complexes might contain additional proteins that regulate the proteolytic activity of SPP or support its non-catalytic functions.

Results: In this study, an unbiased iTRAQ-labeling mass spectrometry approach was used to identify SPP-interacting proteins. We found that vigilin, a ubiquitous multi-KH domain containing cytoplasmic protein involved in RNA binding and protein translation control, selectively enriched with SPP. Vigilin interacted with SPP and both proteins co-localized in restricted intracellular domains near the ER, biochemically co-fractionated and were part of the same 450 kDa complex on BN gels. However, vigilin does not alter the protease activity of SPP, suggesting that the SPP-vigilin interaction might be involved in the non-proteolytic functions of SPP.

Conclusions: We have identified and validated vigilin as a novel interacting partner of SPP that could play an important role in the non-proteolytic functions of SPP. This data adds further weight to the idea that intramembrane-cleaving aspartyl proteases, such as presenilin and SPPs, could have other functions besides the proteolysis of short membrane stubs.
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May 2012

Probing the orientation of yeast VDAC1 in vivo.

FEBS Lett 2009 Feb 29;583(4):739-42. Epub 2009 Jan 29.

The Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, UK.

Voltage dependent anion channel (VDAC) is a vital ion channel in mitochondrial outer membranes and its structure was recently shown to be a 19 stranded beta-barrel. However the orientation of VDAC in the membrane remains unclear. We probe here the topology and membrane orientation of yeast Saccharomyces cerevisiae in vivo. Five FLAG-epitopes were independently inserted into scVDAC1 and their surface exposure in intact and disrupted mitochondria detected by immunoprecipitation. Functionality was confirmed by measurements of respiration. Two epitopes suggest that VDAC (scVDAC) has its C-terminus exposed to the cytoplasm whilst two others are more equivocal and, when combined with published data, suggest a dynamic behavior.
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February 2009