Publications by authors named "Agnes Yuen"

5 Publications

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A multicenter laboratory assessment of a new automated chemiluminescent assay for ADAMTS13 activity.

J Thromb Haemost 2021 02 21;19(2):417-428. Epub 2020 Nov 21.

Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), NSW Health Pathology, Westmead Hospital, Westmead, NSW, Australia.

Background: Thrombotic thrombocytopenic purpura (TTP) is a rare but potentially fatal disorder caused by ADAMTS13 (a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13) deficiency. Prompt identification/exclusion of TTP can thus be facilitated by rapid ADAMTS13 testing. The most commonly utilized (enzyme-linked immunosorbent assay [ELISA]-based) assay takes several hours to perform and so does not generally permit rapid testing.

Objectives: To evaluate the utility of a new automated test for ADAMTS13 activity, the HemosIL AcuStar ADAMTS13 Activity assay, based on chemiluminescence and able to be performed on an ACL AcuStar instrument within 33 minutes.

Patients/methods: This multicenter (n = 8) assessment included testing of more than 700 test samples, with similar numbers of prospective (n = 348) and retrospective (n = 385) samples. The main comparator was the Technozym ADAMTS13 Activity ELISA. We also assessed comparative performance for detection of ADAMTS13 inhibitors using a Bethesda assay.

Results: Overall, the chemiluminescent assay yielded similar results to the comparator ELISA, albeit with slight negative bias. ADAMTS13 inhibitor detection was also comparable, albeit with slight positive bias with the AcuStar assay. Assay precision was similar with both assays, and we also verified assay normal reference ranges.

Conclusions: The HemosIL AcuStar ADAMTS13 Activity assay provided results rapidly, which were largely comparable with the Technozym ADAMTS13 Activity ELISA assay, albeit lower on average. Conversely, inhibitor levels tended to be identified at a higher level on average. Thus, the HemosIL AcuStar ADAMTS13 Activity assay provides a fast and accurate means to quantitate plasma levels of ADAMTS13 for TTP/ADAMTS13 identification/exclusion, and potentially also for other applications.
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http://dx.doi.org/10.1111/jth.15157DOI Listing
February 2021

A multicentre assessment of contemporary laboratory assays for heparin induced thrombocytopenia.

Pathology 2021 Feb 5;53(2):247-256. Epub 2020 Oct 5.

NSW Health Pathology, NSW, Australia; Prince of Wales Hospital, Randwick, NSW, Australia.

Heparin induced thrombocytopenia (HIT) is a rare but potentially fatal complication of heparin therapy. In some patients, HIT causes platelet activation and thrombosis (sometimes abbreviated HITT), which leads to adverse clinical sequalae ('pathological HIT'). The likelihood of HIT is initially assessed clinically, typically using a scoring system, of which the 4T score is that most utilised. Subsequent laboratory testing to confirm or exclude HIT facilitates exclusion or diagnosis and management. The current investigation comprises a multicentre (n=9) assessment of contemporary laboratory testing for HIT, as performed over the past 1-3 years in each site and comprising testing of over 1200 samples. The primary laboratory test used by study participants (n=8) comprised a chemiluminescence procedure (HIT-IgG) performed on an AcuStar instrument. Additional immunological testing performed by study sites included lateral flow (STiC, Stago), enzyme linked immunosorbent assay (ELISA), Asserachrom (HPIA IgG), PaGIA (BioRad), plus functional assays, primarily serotonin release assay (SRA) or platelet aggregation methods. The chemiluminescence procedure yielded a highly sensitive screening method for identifying functional HIT, given high area under the curve (AUC, generally ≥0.9) in a receiver operator characteristic (ROC) analysis against SRA as gold standard. ELISA testing resulted in lower ROC AUC scores (<0.8) and higher levels of false positives. Although there is clear association with the likelihood of HIT, the 4T score had less utility than literature suggests, and was comparable to a previous study reported by some of the authors.
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http://dx.doi.org/10.1016/j.pathol.2020.07.012DOI Listing
February 2021

Particle Depletion Does Not Remediate Acute Effects of Traffic-related Air Pollution and Allergen. A Randomized, Double-Blind Crossover Study.

Am J Respir Crit Care Med 2019 09;200(5):565-574

Air Pollution Exposure Laboratory, Division of Respiratory Medicine, Department of Medicine, and.

Diesel exhaust (DE), an established model of traffic-related air pollution, contributes significantly to the global burden of asthma and may augment the effects of allergen inhalation. Newer diesel particulate-filtering technologies may increase NO emissions, raising questions regarding their effectiveness in reducing harm from associated engine output. To assess the effects of DE and allergen coexposure on lung function, airway responsiveness, and circulating leukocytes, and determine whether DE particle depletion remediates these effects. In this randomized, double-blind crossover study, 14 allergen-sensitized participants (9 with airway hyperresponsiveness) underwent inhaled allergen challenge after 2-hour exposures to DE, particle-depleted DE (PDDE), or filtered air. The control condition was inhaled saline after filtered air. Blood sampling and spirometry were performed before and up to 48 hours after exposures. Airway responsiveness was evaluated at 24 hours. PDDE plus allergen coexposure impaired lung function more than DE plus allergen, particularly in those genetically at risk. DE plus allergen and PDDE plus allergen each increased airway responsiveness in normally responsive participants. DE plus allergen increased blood neutrophils and was associated with persistent eosinophilia at 48 hours. DE and PDDE each increased total peripheral leukocyte counts in a manner affected by participant genotypes. Changes in peripheral leukocytes correlated with lung function decline. Coexposure to DE and allergen impaired lung function, which was worse after particle depletion (which increased NO). Thus, particulates are not necessarily the sole or main culprit responsible for all harmful effects of DE. Policies and technologies aimed at protecting public health should be scrutinized in that regard.Clinical trial registered with www.clinicaltrials.gov (NCT02017431).
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http://dx.doi.org/10.1164/rccm.201809-1657OCDOI Listing
September 2019

Lifestyle and medication interventions for the prevention or delay of type 2 diabetes mellitus in prediabetes: a systematic review of randomised controlled trials.

Aust N Z J Public Health 2010 Apr;34(2):172-8

Emergency Practice Innovation Centre, St Vincent's Hospital Melbourne and Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Victoria, Australia.

Objective: To assess lifestyle and pharmacological interventions aiming to delay type 2 diabetes mellitus (T2DM) in prediabetes.

Methods: We searched the Cochrane Register of Controlled Trials, MEDLINE, EMBASE, CINAHL, PsycINFO, Web of Science, BIOSIS and LILACS databases, examined reference lists and contacted authors. We included randomised controlled trials (RCTs) on both lifestyle and medication interventions in prediabetes. These studies were at least 12 month duration and aimed to delay T2DM.

Results: Four studies investigating lifestyle and medication with a total of 5,196 participants were identified. There was a high risk of bias in the studies and the interventions utilised varied considerably; thus, meta-analysis was not undertaken. The comparison between lifestyle and medication interventions was largely dependent on the intensity of the lifestyle program while we could not adequately assess their effects on cardiovascular morbidity. Adverse events with metformin and acarbose were common.

Conclusion: There is substantial evidence that intensive lifestyle programs and medications delay T2DM in impaired glucose tolerance though it remains unclear which is more effective.

Implications: Both interventions seem to be able to delay T2DM. However, both have issues with adherence and side effects and more RCTs are required.
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http://dx.doi.org/10.1111/j.1753-6405.2010.00503.xDOI Listing
April 2010