Publications by authors named "J-S Koh"

Article Synopsis
  • - Volkmann's ischemic contracture involves permanent muscle and nerve damage from insufficient blood flow, leading to flexion contractures, whereas pseudo-Volkmann's contracture shares similar symptoms but can fully recover without ischemic damage.
  • - A case study describes a 39-year-old man who experienced finger extension failure after blunt forearm trauma, showing progressive symptoms over two months despite no broken skin or bones.
  • - Surgical intervention after two years revealed severe muscle adhesions due to the trauma, and immediate recovery was achieved after the adhesions were released, suggesting a diagnosis of pseudo-Volkmann's contracture.
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Studies in Western populations have shown that Black and Hispanic patients have an earlier age of Multiple Sclerosis (MS) onset and a more severe disease course characterised by faster disability accrual compared to Whites. It is yet unclear whether MS disease characteristics and clinical course differ amongst Asian racial groups. Singapore is uniquely poised to investigate this as its multi-racial population comprises three genetically diverse Asian racial groups-Chinese, Malay and South Asian.

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Objective: Within the past decade, Medicare Part B reimbursements for various surgical procedures have been declining, whereas health care expenses continue to increase. As a result, hospitals may increase service charges to offset losses in revenue, which may disproportionately affect underinsured patients. Our analysis aimed to characterize Medicare billing and utilization trends across common vascular surgical procedures.

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While most dizygotic twins have a dichorionic placenta, rare cases of dizygotic twins with a monochorionic placenta have been reported. The monochorionic placenta in dizygotic twins allows in utero exchange of embryonic cells, resulting in chimerism in the twins. In practice, this chimerism is incidentally identified in mixed ABO blood types or in the presence of cells with a discordant sex chromosome.

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Background: The Murray law-based quantitative flow ratio (μFR) is an emerging technique that requires only 1 projection of coronary angiography with similar accuracy to quantitative flow ratio (QFR). However, it has not been validated for the evaluation of noninfarct-related artery (non-IRA) in acute myocardial infarction (AMI) settings. Therefore, our study aimed to evaluate the diagnostic accuracy of μFR and the safety of deferring non-IRA lesions with μFR >0.

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 Skin defects in the hands are common injuries, and autologous skin grafting is the ideal treatment. However, complications can occur at the donor and recipient sites. This study compares the "Swing-door" technique with conventional skin grafting.

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Percutaneous first annular pulley (A1 pulley) release, which has been increasingly used to treat trigger fingers, has been widely established as a safe and simple procedure. Multiple studies have reported positive results of percutaneous A1 pulley release. In this study, however, we report cases of patients who developed complications after undergoing percutaneous A1 pulley release at local clinics.

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This study aimed to analyze cases of anterolateral thigh (ALT) free flap used for hand reconstruction with terminal perforator-to-digital artery anastomosis. Patients who underwent ALT free flap placement with terminal perforator-to-digital artery anastomosis for hand reconstruction between January 2011 and August 2021 were included. The number, length, and diameter of the perforators and veins, flap size, and operative time were investigated through a retrospective review of charts and photographs.

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Article Synopsis
  • Type 2 diabetes (T2D) is a complex disease influenced by various genetic factors and molecular mechanisms that vary by cell type and ancestry.
  • In a large study involving over 2.5 million individuals, researchers identified 1,289 significant genetic associations linked to T2D, including 145 new loci not previously reported.
  • The study categorized T2D signals into eight distinct clusters based on their connections to cardiometabolic traits and showed that these genetic profiles are linked to vascular complications, emphasizing the role of obesity-related processes across different ancestry groups.
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Background: The RENOVATE-COMPLEX-PCI (Randomized Controlled Trial of Intravascular Imaging Guidance Versus Angiography-Guidance on Clinical Outcomes After Complex Percutaneous Coronary Intervention) demonstrated that intravascular imaging-guided percutaneous coronary intervention (PCI) improved clinical outcome compared with angiography-guided PCI for patients with complex coronary artery lesions. This study aims to assess whether the prognostic benefit of intravascular imaging-guided procedural optimization persists in patients undergoing PCI for left main coronary artery disease.

Methods: Of 1639 patients enrolled in the RENOVATE-COMPLEX-PCI, 192 patients with left main coronary artery disease were selected for the current prespecified substudy.

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Article Synopsis
  • The study examines the effectiveness of fractional flow reserve (FFR)-guided versus angiography-guided percutaneous coronary intervention (PCI) for non-infarct-related artery lesions in patients with acute myocardial infarction, focusing on severe stenosis.
  • Among 562 patients, those receiving FFR-guided PCI had significantly lower rates of adverse outcomes (death, myocardial infarction, or repeat revascularization) compared to those who had angiography-guided PCI, particularly in cases with severe stenosis (≥70%).
  • The findings suggest that FFR-guided PCI is superior in reducing complications for both severe (≥70%) and less severe (<70%) non-IRA stenosis, indicating its potential benefit for patients with acute myocardial infarction
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Background: Radium-223 is a bone-seeking, ɑ-emitting radionuclide used to treat men with bone metastases from castration-resistant prostate cancer. Sclerotic bone lesions cannot be evaluated using Response Evaluation Criteria in Solid Tumors. Therefore, imaging response biomarkers are needed.

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Type 2 diabetes (T2D) is a heterogeneous disease that develops through diverse pathophysiological processes. To characterise the genetic contribution to these processes across ancestry groups, we aggregate genome-wide association study (GWAS) data from 2,535,601 individuals (39.7% non-European ancestry), including 428,452 T2D cases.

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Background: Data regarding clinical outcomes after intravascular imaging-guided percutaneous coronary intervention (PCI) for complex coronary-artery lesions, as compared with outcomes after angiography-guided PCI, are limited.

Methods: In this prospective, multicenter, open-label trial in South Korea, we randomly assigned patients with complex coronary-artery lesions in a 2:1 ratio to undergo either intravascular imaging-guided PCI or angiography-guided PCI. In the intravascular imaging group, the choice between intravascular ultrasonography and optical coherence tomography was at the operators' discretion.

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Epithelial responses to the cytokine interleukin-13 (IL-13) cause airway obstruction in asthma. Here we utilized multiple genomic techniques to identify IL-13-responsive regulatory elements in bronchial epithelial cells and used these data to develop a CRISPR interference (CRISPRi)-based therapeutic approach to downregulate airway obstruction-inducing genes in a cell type- and IL-13-specific manner. Using single-cell RNA sequencing (scRNA-seq) and acetylated lysine 27 on histone 3 (H3K27ac) chromatin immunoprecipitation sequencing (ChIP-seq) in primary human bronchial epithelial cells, we identified IL-13-responsive genes and regulatory elements.

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Background: Mutations in PIEZO1 (Piezo type mechanosensitive ion channel component 1) cause human lymphatic malformations. We have previously uncovered an ORAI1 (ORAI calcium release-activated calcium modulator 1)-mediated mechanotransduction pathway that triggers lymphatic sprouting through Notch downregulation in response to fluid flow. However, the identity of its upstream mechanosensor remains unknown.

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Asthma is a chronic inflammatory lung disease with intermittent flares predominately mediated through memory T cells. Yet, the identity of long-term memory cells that mediate allergic recall responses is not well defined. In this report, using a mouse model of chronic allergen exposure followed by an allergen-free rest period, we characterized a subpopulation of CD4 T cells that secreted IL-9 as an obligate effector cytokine.

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Background And Purpose: Changes in connectivity of white matter fibers remote to a stroke lesion, suggestive of structural connectional diaschisis, may impact on clinical impairment and recovery after stroke. However, until recently, we have not had tract-specific techniques to map changes in white matter tracts in vivo in humans to enable investigation of potential mechanisms and clinical impact of such remote changes. Our aim was to identify and quantify white matter tracts that are affected remote from a stroke lesion and to investigate the associations between reductions in tract-specific connectivity and impaired touch discrimination function after stroke.

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Evidence-based contact lens -->practice involves finding, appraising and applying research findings as the basis for patient management decisions. These decisions should be informed by the strength of the research study designs that address the question, as well as by the experience of the practitioner and the preferences and environment of the patient. This reports reviews and summarises the published research evidence that is available to inform soft and rigid contact lens history and symptoms taking, anterior eye health examination (including the optimised use of ophthalmic dyes, grading scales, imaging techniques and lid eversion), considerations for contact lens selection (including the ocular surface measurements required to select the most appropriate lens parameter, lens modality and material selection), evaluation of lens fit, prescribing (teaching self-application and removal, adaptation, care regimen and cleaning instructions, as well as -->minimising risks of lens wear through encouraging compliance) and an aftercare routine.

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Background: Microvascular dysfunction is known to play a key role in patients with angina and nonobstructive coronary artery disease. We investigated the impact of ranolazine among patients with angina and nonobstructive coronary artery disease.

Methods: In this randomized, double-blinded, placebo-controlled pilot trial, 26 patients with angina once weekly or more, abnormal stress test, and nonobstructive coronary artery disease (<50% stenosis by angiography and fractional flow reserve >0.

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Objective: To identify common genetic variants associated with the presence of brain microbleeds (BMBs).

Methods: We performed genome-wide association studies in 11 population-based cohort studies and 3 case-control or case-only stroke cohorts. Genotypes were imputed to the Haplotype Reference Consortium or 1000 Genomes reference panel.

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Real world data on clinical outcomes and quality of care for patients with coronary artery disease (CAD) are fragmented. We describe the rationale and design of the Singapore Cardiovascular Longitudinal Outcomes Database (SingCLOUD). We designed a health data grid to integrate clinical, administrative, laboratory, procedural, prescription and financial data from all public-funded hospitals and primary care clinics, which provide 80% of health care in Singapore.

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In many species, the offspring of related parents suffer reduced reproductive success, a phenomenon known as inbreeding depression. In humans, the importance of this effect has remained unclear, partly because reproduction between close relatives is both rare and frequently associated with confounding social factors. Here, using genomic inbreeding coefficients (F) for >1.

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Background: Global dietary recommendations for and cardiovascular effects of linoleic acid, the major dietary omega-6 fatty acid, and its major metabolite, arachidonic acid, remain controversial. To address this uncertainty and inform international recommendations, we evaluated how in vivo circulating and tissue levels of linoleic acid (LA) and arachidonic acid (AA) relate to incident cardiovascular disease (CVD) across multiple international studies.

Methods: We performed harmonized, de novo, individual-level analyses in a global consortium of 30 prospective observational studies from 13 countries.

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