Publications by authors named "Chew Chai"

Live imaging of regenerative processes can reveal how animals restore their bodies after injury through a cascade of dynamic cellular events. Here, we present a comprehensive toolkit for live imaging of tissue regeneration in the flatworm Macrostomum lignano, including a high-throughput cloning pipeline, targeted cellular ablation, and advanced microscopy solutions. Using tissue-specific reporter expression, we examine how various structures regenerate.

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Article Synopsis
  • Cell types are organized into a hierarchy with related types grouped into families, but how they stay distinct over time is not well understood.
  • By combining advanced sequencing techniques and deep learning, researchers identified specific sequence features (motifs) that are linked to the genomes of particular cell type families across diverse animal groups like flatworms and cnidarians.
  • The stability of cell type families is thought to come from a set of conserved motifs, while the diversity of specific cell types within those families arises from flexible combinations of these motifs.
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Animal behavior emerges from collective dynamics of neurons, making it vulnerable to damage. Paradoxically, many organisms exhibit a remarkable ability to maintain significant behavior even after large-scale neural injury. Molecular underpinnings of this extreme robustness remain largely unknown.

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The remarkable regenerative abilities of flatworms are closely linked to neoblasts - adult pluripotent stem cells that are the only division-competent cell type outside of the reproductive system. Although the presence of neoblast-like cells and whole-body regeneration in other animals has led to the idea that these features may represent the ancestral metazoan state, the evolutionary origin of both remains unclear. Here we show that the catenulid , a member of the earliest-branching flatworm lineage, lacks conventional neoblasts despite being capable of whole-body regeneration and asexual reproduction.

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Injury induces systemic responses, but their functions remain elusive. Mechanisms that can rapidly synchronize wound responses through long distances are also mostly unknown. Using planarian flatworms capable of whole-body regeneration, we report that injury induces extracellular signal-regulated kinase (Erk) activity waves to travel at a speed 10-100 times faster than those in other multicellular tissues.

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Capture array-based spatial transcriptomics methods have been widely used to resolve gene expression in tissues; however, their spatial resolution is limited by the density of the array. Here we present expansion spatial transcriptomics to overcome this limitation by clearing and expanding tissue prior to capturing the entire polyadenylated transcriptome with an enhanced protocol. This approach enables us to achieve higher spatial resolution while retaining high library quality, which we demonstrate using mouse brain samples.

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Injury induces systemic, global responses whose functions remain elusive. In addition, mechanisms that rapidly synchronize wound responses through long distances across the organismal scale are mostly unknown. Using planarians, which have extreme regenerative ability, we report that injury induces Erk activity to travel in a wave-like manner at an unexpected speed (∼1 mm/h), 10-100 times faster than those measured in other multicellular tissues.

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Animal behavior emerges from collective dynamics of interconnected neurons, making it vulnerable to connectome damage. Paradoxically, many organisms maintain significant behavioral output after large-scale neural injury. Molecular underpinnings of this extreme robustness remain largely unknown.

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Article Synopsis
  • Planarians are being studied for their ability to regenerate, with new tools for expressing non-native proteins proving to be valuable for research.
  • The study utilizes a luminescent reporter to avoid the strong autofluorescence in planarian tissues, facilitating the introduction and measurement of mRNA in living planarians.
  • By modifying untranslated regions (UTRs) and investigating protein expression, this research lays the groundwork for understanding gene regulation and enhances methods for using planarians in genetic studies.
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Introduction: Intubations in the emergency department (ED) are often performed immediately without the benefit of pre-selection or the ability to defer. Multicentre observational data provide a framework for understanding emergency airway management but regional practice variation may exist. We aim to describe the intubation indications, prevalence of difficult airway features, peri-intubation adverse events and intubator characteristics in the ED of the National University Hospital, Singapore.

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Retinal blood vessels provide information on the risk of cardiovascular disease (CVD). Here, we report the development and validation of deep-learning models for the automated measurement of retinal-vessel calibre in retinal photographs, using diverse multiethnic multicountry datasets that comprise more than 70,000 images. Retinal-vessel calibre measured by the models and by expert human graders showed high agreement, with overall intraclass correlation coefficients of between 0.

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Introduction: This study aimed to assess the effectiveness of the emergency department observation unit (EDOU) for patients with acute pyelonephritis in a Singapore tertiary academic medical centre.

Methods: We reviewed the clinical records of consecutive patients who presented with pyelonephritis between 1 July 2012 and 31 October 2014 to collect information on demographics, symptoms, signs, laboratory and radiological results, treatment, and clinical outcomes.

Results: Of 459 emergency department (ED) patients who were identified as having pyelonephritis, 164 (35.

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Uropathogenic (UPEC) are the major causative agents of urinary tract infections, employing numerous molecular strategies to contribute to adhesion, colonization, and persistence in the bladder niche. Identifying strategies to prevent adhesion and colonization is a promising approach to inhibit bacterial pathogenesis and to help preserve the efficacy of available antibiotics. This approach requires an improved understanding of the molecular determinants of adhesion to the bladder urothelium.

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Background: Dyspepsia is a common complaint that can confer significant burden on one's quality of life and may also be associated with serious underlying conditions. The objective of this study was to determine if patients admitted to the emergency department observation unit (EDOU) for severe or persistent dyspepsia would have cost effective management in terms of investigations performed, length and cost of hospital stay. The secondary objective was to determine if any patient characteristics could predict a need for admission to the inpatient unit.

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Thin liquid films are central to everyday life. They are ubiquitous in modern technology (pharmaceuticals, coatings), consumer products (foams, emulsions) and also serve vital biological functions (tear film of the eye, pulmonary surfactants in the lung). A common feature in all these examples is the presence of surface-active molecules at the air-liquid interface.

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Purpose: An experimental platform to replicate the human tear film on a contact lens is presented. The influence of interfacial viscoelasticity in stabilizing in vitro model tear films against breakup and dewetting is investigated using this instrument.

Methods: Model tear films consisting of bovine meibomian lipids (meibum) spread on either PBS or artificial tear solution (ATS) are created.

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