Publications by authors named "Liew O"

In gel electrophoresis, samples that are dispensed too high above or too low into the wells result in sub-optimal outcomes. Here, an adapted 3D printer liquid handler equipped with an optical sensor was found to attain vertical sample delivery positionings at a standard deviation over mean ratio of 0.008.

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  • * Conducted on 122 patients with moderate to severe aortic stenosis, the research identified specific circulating proteins that correlate with higher risks of heart failure, severe symptoms, and mortality.
  • * Key proteins linked to inflammation and immune responses were significantly associated with worse outcomes, particularly in patients showing reduced heart strain, suggesting new avenues for assessing patient risk beyond standard imaging methods.
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Purpose: To investigate the diversity of ocular manifestations in patients with positive perinuclear antineutrophil cytoplasmic antibody (p-ANCA).

Methods: The clinical records of five patients exhibiting ocular manifestations and testing positive for serum MPO-ANCA were retrospectively reviewed.

Results: Three out of five patients were female.

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Aims: The performance of circulating soluble urokinase plasminogen activator receptor (suPAR) for predicting the composite endpoint of subsequent heart failure (HF) hospitalisation and/or death at 1 year was assessed in (i) patients with undifferentiated breathlessness, and generalisability was compared in (ii) disparate Western versus Asian sub-cohorts, and in (iii) the sub-cohort adjudicated with HF.

Methods And Results: Patients with acute breathlessness were recruited from the emergency departments in New Zealand (NZ, n = 612) and Singapore (n = 483). suPAR measured in the presentation samples was higher in patients incurring the endpoint (n = 281) compared with survivors (5.

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  • The study aimed to explore how serial measurements of NT-proBNP, a heart failure biomarker, relate to cardiac changes and patient outcomes, considering various clinical factors.
  • Analysis involved 1911 heart failure patients, revealing that NT-proBNP levels generally declined, especially in certain groups like inpatients and those on guideline-recommended medications.
  • An increase in NT-proBNP over time was linked to a higher risk of hospitalization or death, with variations noted based on patient age, atrial fibrillation presence, and heart failure types.
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  • Heart failure (HF) and diabetes worsen each other’s outcomes, and this study evaluated global longitudinal strain (GLS) as a prognostic marker in HF patients with diabetes.
  • In a study of 315 HF patients, those with diabetes showed significantly worse cardiovascular indicators, such as higher late gadolinium enhancement rates and elevated biomarker levels compared to non-diabetic patients.
  • The results indicated that patients with diabetes not only had poorer health indicators but also a worse prognosis, with GLS and soluble ST2 biomarkers emerging as independent prognostic factors for adverse outcomes.
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Aim: Pathophysiological differences between patients with heart failure with preserved (HFpEF) and reduced (HFrEF) ejection fraction (EF) remain unclear. Therefore we used a phenomics approach, integrating selected proteomics data with patient characteristics and cardiac structural and functional parameters, to get insight into differential pathophysiological mechanisms and identify potential treatment targets.

Methods And Results: We report data from a representative subcohort of the prospective Singapore Heart Failure Outcomes and Phenotypes (SHOP), including patients with HFrEF (EF <40%, n = 217), HFpEF (EF ≥50%, n = 213), and age- and sex-matched controls without HF (n = 216).

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Objectives: In dyspneic patients with atrial fibrillation (AF) or obesity, the diagnostic performance of NT-proBNP for acute heart failure is reduced. We evaluated the erythroblast derived protein erythroferrone (ERFE) as an ancillary biomarker for the diagnosis of acute decompensated heart failure (ADHF) in these comorbid subgroups in both Western and Asian populations.

Methods: The diagnostic performance of ERFE (Intrinsic Lifesciences) and NT-proBNP (Roche Cobas e411) for ADHF was assessed in 479 New Zealand (NZ) and 475 Singapore (SG) patients presenting with breathlessness.

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Neprilysin (NEP) is an emerging biomarker for various diseases including heart failure (HF). However, major inter-assay inconsistency in the reported concentrations of circulating NEP and uncertainty with respect to its correlations with type and severity of disease are in part attributed to poorly characterized antibodies supplied in commercial ELISA kits. Validated antibodies with well-defined binding footprints are critical for understanding the biological and clinical context of NEP immunoassay data.

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Background: Natriuretic peptide (NP) elevations are prognostic in heart failure (HF), but relative atrial NP deficiency in acute HF has been suggested.

Objectives: The authors compared plasma concentrations and relative strength of associations of A- and B-type NPs with cardiac structure/function and clinical outcomes in HF.

Methods: Midregional pro-atrial natriuretic peptide (MR-proANP), B-type natriuretic peptide (BNP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were measured in patients with compensated HF in a prospective, multicenter study.

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  • * Using speckle-tracking echocardiography, researchers measured three types of LA strain and tracked patient outcomes over an average of 2.7 years, finding that lower strain values correlated with worse clinical results.
  • * LA strain metrics (particularly LASr < 20%) demonstrated superior prognostic value compared to traditional echocardiographic variables and were strongly linked to adverse outcomes like heart failure hospitalizations and mortality.
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This chapter describes an epitope-directed approach to generate antipeptide monoclonal antibodies to multiple nonoverlapping protein sites using a cocktail of fusion peptides as immunogen. It provides a step-by-step protocol on how antigenic peptides on a target protein can be identified by in silico prediction and discusses considerations for final peptide selection. Each antigenic peptide (10-20 amino acids long) is displayed as three-copy inserts on the surface exposed loop of a thioredoxin scaffold protein.

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Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) inactivation is an important step toward enhanced biosafety in testing facilities and affords a reduction in the biocontainment level necessary for handling virus-positive biological specimens. Virus inactivation methods commonly employ heat, detergents, or combinations thereof. In this work, we address the dearth of information on the efficacy of SARS-CoV-2 inactivation procedures in plasma and their downstream impact on immunoassays.

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Background: Plasma cardiac markers may assist in prediction of incident cardiovascular disease.

Methods: The incremental value of cardiac Troponins (T and I) and NT-proBNP added to risk factors in the PREDICT score for incident cardiovascular disease (CVD) in primary care, was assessed in 4102 asymptomatic participants in a randomised controlled trial of Vitamin D (ViDA). Findings were corroborated in 2528 participants in a separate community-based observational registry of CVD-free volunteers (HVOLS).

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Xeropthalmia refers to a range of ocular symptoms caused by vitamin A deficiency (VAD), ranging from night blindness and Bitot's spots to corneal xerosis, ulceration, and keratomalacia, which can lead to blindness. We report two cases of xerophthalmia in children with intellectual disabilities. Ocular examination revealed generalized conjunctival xerosis, corneal xerosis, and dense superficial punctate keratopathy.

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  • The study aimed to find the significance of various biomarkers in predicting outcomes for patients with aortic stenosis (AS), particularly in terms of mortality and heart failure.
  • Researchers measured biomarkers like NT-proBNP, hsTnT, and MR-proADM in 173 patients with moderate to severe AS over several years, analyzing their effectiveness in predicting primary and secondary health outcomes.
  • Results indicated that MR-proADM had the strongest correlation with worse health outcomes, suggesting it could be the key biomarker for assessing risk in AS patients.
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Background: Lack of validation and standardization of research-use-only (RUO) immunoassays brings with it inherent threats to authenticity and functional quality. Poor correlation between different commercial neprilysin RUO immunoassays is concerning and discordant findings need to be resolved. We seek to identify and validate reliable neprilysin immunoassays to strengthen the scientific rigor and reproducibility of neprilysin-related investigation and of biomarker research in general.

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The effects of vitamin D supplementation on cardiovascular diseases are controversial. Data on effects of vitamin D upon cardiac biomarkers, as surrogate endpoints of cardiovascular diseases, are limited and inconclusive. Therefore, we carried out a post-hoc analysis of sub-samples of a randomized, double-blinded, placebo-controlled trial with community-based older adults who were randomized to receive monthly 100,000-IU vitamin D or placebo, to determine effect of monthly vitamin D supplementation on high-sensitivity cardiac troponin I (hs-cTnI), troponin T (hs-cTnT) and N-terminal-pro-B-type natriuretic peptide (NT-proBNP).

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Highly wetting and nonwetting substrates have been widely used in fogwater collection systems for enhanced water harvesting. In this work, fog harvesting substrates comprising PVC strips of different wetting properties and widths ranging from 1-5 mm were vertically aligned and spaced apart at regular intervals to give the same solid area fraction of 0.8.

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Low-cost analytical solutions built around microcomputers like the Raspberry Pi help to facilitate laboratory investigations in resource limited venues. Here, three camera modules (V1.3 with and without filter, as well as NoIR) that work with this microcomputer were assessed for their suitability in imaging fluorescent DNA following agarose gel electrophoresis.

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Cryopreservation is a widely used long-term preservation method to ensure the quality and vitality of microbes in laboratories and biological resource facilities. However, freeze-thaw damage and osmotic pressure changes during cryopreservation adversely impacts microbial survival. Significant expenditure of resources and expertise are required to select the right cryoprotectant and optimize its concentration for maximum survival of diverse microorganisms.

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Background And Purpose: Cardiac biomarkers, NT-proBNP (N-terminal probrain natriuretic peptide), hs-cTnT (high-sensitivity-cardiac troponin T), and GDF-15 (growth differentiation factor-15) have been proposed as important biomarkers of early vascular pathology. However, little is known of the longitudinal associations of these cardiac biomarkers with cerebrovascular disease and clinical events. We examine the association of blood-based cardiac biomarkers (NT-proBNP, hs-cTnT, and GDF-15) with cognitive decline, incident cerebrovascular disease, vascular events, and mortality.

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High quality, well-validated antibodies are needed to mitigate irreproducibility and clarify conflicting data in science. We describe an epitope-directed monoclonal antibody (mAb) production method that addresses issues of antibody quality, validation and utility. The workflow is illustrated by generating mAbs against multiple in silico-predicted epitopes on human ankyrin repeat domain 1 (hANKRD1) in a single hybridoma production cycle.

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