Publications by authors named "Edmund Chan"

Weight loss through exercise and diet reduces the risk of type 2 diabetes, but the genetic regulation of gene expression and splicing in response to weight loss remains unclear in humans. We collected clinical data and skeletal muscle biopsies from 54 overweight/obese Asian individuals before and after a 16-week lifestyle intervention, which resulted in an average of ∼10% weight loss, accompanied by an ∼30% increase in insulin-stimulated glucose uptake. Improvements were observed in 118 of 252 clinical traits and six blood lipids.

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Ovarian cancer (OC) must be detected in its early stages when the mortality rate is the lowest to provide patients with the best chance of survival. Lysophosphatidic acid (LPA) is a critical OC biomarker since its levels are elevated across all stages and increase with disease progression. This paper presents an LPA assay based on a thickness shear mode acoustic sensor with dissipation monitoring that involves a new thiol molecule 3-(2-mercaptoethanoxy)propanoic acid (HS-MEG-COOH).

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Importance: While UV radiation displays may be used for recreational purposes at outdoor events, unprotected eyes have been reported to have symptoms consistent with photokeratitis. Such symptoms warrant documentation and evaluation in ophthalmic peer reviewed literature.

Objective: To describe a case series of photokeratitis associated with a single ultraviolet radiation display at an outdoor event.

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Large-scale gene sequencing studies for complex traits have the potential to identify causal genes with therapeutic implications. We performed gene-based association testing of blood lipid levels with rare (minor allele frequency < 1%) predicted damaging coding variation by using sequence data from >170,000 individuals from multiple ancestries: 97,493 European, 30,025 South Asian, 16,507 African, 16,440 Hispanic/Latino, 10,420 East Asian, and 1,182 Samoan. We identified 35 genes associated with circulating lipid levels; some of these genes have not been previously associated with lipid levels when using rare coding variation from population-based samples.

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Article Synopsis
  • - The study investigates the genetic variants linked to severe monogenic diseases, focusing on the unknown probability (penetrance) of these variants causing disease.
  • - Using exome sequencing data from over 77,000 individuals, researchers examine eight monogenic metabolic diseases, finding that rare variants have a greater impact than common polygenic scores.
  • - Despite the strong effect of rare variants, the average penetrance for monogenic variant carriers is only about 60%, although incorporating polygenic variation helps improve risk prediction for certain conditions.
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Background: The infiltration between the popliteal artery and the capsule of the knee (IPACK) block has been described as an alternative analgesic strategy for knee pain.

Objective: Our aim was to perform a narrative review to examine the place and value that the IPACK block has in comparison to and in conjunction with other regional anesthesia modalities.

Evidence Review: Following an extensive search of electronic databases, we included anatomical studies, letters, comparative observational studies, and non-randomized and randomized controlled trials that examined the IPACK block in relation to surgery on the knee under general or neuraxial anesthesia.

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Purpose: Regional anesthesia techniques may improve patient recovery beyond treating postoperative pain alone and may facilitate patients in their return to functional, psychological as well as emotional baselines. We hypothesized that the quality of recovery (QoR) experienced by patients following breast surgery was associated with the type of anesthesia received as well as the use of a regional anesthesia technique during surgery.

Methods: We performed a single-center prospective, observational cohort study of patients undergoing elective breast procedures (both cancer and non-cancer surgery).

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Background: Caudal block is a well-established technique for providing perioperative analgesia in pediatric genitourinary surgery, but abdominal wall blocks such as ilioinguinal-iliohypogastric (II-IH) and transversus abdominis plane (TAP) block are increasingly being used.

Methods: Our protocol for this meta-analysis was registered on PROSPERO (CRD42020163497). Central, CINAHL, Embase, Global Health, LILACS, MEDLINE, Scopus and Web of Science were searched from inception to 11 December 2019 for randomized controlled trials that included pediatric patients having genitourinary surgery with II-IH or TAP block as the intervention and caudal analgesia as the comparator.

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Protein-coding genetic variants that strongly affect disease risk can yield relevant clues to disease pathogenesis. Here we report exome-sequencing analyses of 20,791 individuals with type 2 diabetes (T2D) and 24,440 non-diabetic control participants from 5 ancestries. We identify gene-level associations of rare variants (with minor allele frequencies of less than 0.

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To investigate the genetic basis of type 2 diabetes (T2D) to high resolution, the GoT2D and T2D-GENES consortia catalogued variation from whole-genome sequencing of 2,657 European individuals and exome sequencing of 12,940 individuals of multiple ancestries. Over 27M SNPs, indels, and structural variants were identified, including 99% of low-frequency (minor allele frequency [MAF] 0.1-5%) non-coding variants in the whole-genome sequenced individuals and 99.

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Article Synopsis
  • Researchers analyzed genetic data from over 39,000 people to find new associations linked to glycemic traits and type 2 diabetes risk.
  • They discovered a specific variant (p.Pro50Thr) that increases fasting plasma insulin levels by 12%, particularly in individuals of Finnish descent.
  • This variant is associated with lower insulin sensitivity and a slightly higher risk of developing type 2 diabetes, highlighting its functional impact in glucose regulation.
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Article Synopsis
  • The study investigates the relationship between the 5HTTLPR L allele (a genetic variant) and blood pressure levels, as well as hypertension prevalence, using data from large samples in the U.S. and Singapore.
  • Results indicate that for U.S. Whites, those with the L allele had higher systolic blood pressure (SBP) and were more likely to experience severe hypertension, while African Americans showed lower SBP and odds of severe hypertension with the same allele.
  • The findings suggest that the impact of the L allele on blood pressure and hypertension varies significantly across different racial and ethnic groups, highlighting the influence of genetic factors on cardiovascular health.
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The genetic architecture of common traits, including the number, frequency, and effect sizes of inherited variants that contribute to individual risk, has been long debated. Genome-wide association studies have identified scores of common variants associated with type 2 diabetes, but in aggregate, these explain only a fraction of the heritability of this disease. Here, to test the hypothesis that lower-frequency variants explain much of the remainder, the GoT2D and T2D-GENES consortia performed whole-genome sequencing in 2,657 European individuals with and without diabetes, and exome sequencing in 12,940 individuals from five ancestry groups.

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Context: Among Asian ethnic groups, Chinese or Malays are more insulin sensitive than South Asians, in particular in lean individuals. We have further reported that body fat partitioning did not explain this ethnic difference in insulin sensitivity.

Objective: We examined whether adipocytokines might explain the ethnic differences in the relationship between obesity and insulin resistance among the three major ethnic groups in Singapore.

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Adipose-derived stem/stromal cells (ASCs) from the anatomically distinct subcutaneous and visceral depots of white adipose tissue (WAT) differ in their inherent properties. However, little is known about the molecular identity and definitive markers of ASCs from these depots. In this study, ASCs from subcutaneous fat (SC-ASCs) and visceral fat (VS-ASCs) of omental region were isolated and studied.

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Context: Isolated elevation of TSH in the absence of thyroid symptoms can be very rarely caused by a macromolecule formed between TSH and Ig (macro-TSH), confounding the interpretation of thyroid function test results.

Objective: We described the use of several commonly available laboratory-based approaches to investigate an isolated TSH elevation [232 mIU/liter; free T(4), 10 pmol/liter (reference interval, 10.0-23.

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This project aimed to identify problems in the management of Parkinson's Disease (PD) medications in those acutely admitted to the medical ward. Errors in prescription of medications are due to difficulties in conversion of formulation of medications to suit different needs, lack of awareness of help available amongst junior doctors and lack of awareness of trust guidance. Drug charts were audited over two weeks on medical wards.

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Background: High-density lipoprotein (HDL) encompasses a heterogeneous population of lipoproteins with differences in functionality. The impact of HDL heterogeneity on its ability to support HDL-mediated cholesterol efflux has not been previously studied in patients with type 2 diabetes mellitus (T2DM).

Objectives: To examine the relationships between various HDL subtypes and cholesterol efflux from macrophages in patients with T2DM.

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Peroxisome proliferators activated receptor alpha (PPARalpha) regulates the transcription of several proteins involved in human lipoprotein metabolism. We screened the PPARA locus for polymorphisms in 20 unrelated subjects from each of three ethnic groups (Chinese, Malays and Asian Indians). Only the V227A polymorphism was observed.

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Microbial structures activate Toll-like receptors (TLRs) and TLR-mediated cell signalling elicits and regulates host immunity. Most TLRs are poorly expressed but the underlying expression mechanism is not clear. Examination TLR sequences revealed that most human TLR genes deviated from using major human codons.

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