Publications by authors named "Christopher McMaster"

The World Health Organization has identified antibiotic resistance as one of the three greatest threats to human health. The need for antibiotics is a pressing matter that requires immediate attention. Here, computer-aided drug design is used to develop a structurally unique antibiotic family targeting holo-acyl carrier protein synthase (AcpS).

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Phosphatidylcholine (PC) is the major membrane phospholipid in most eukaryotic cells. Bi-allelic loss of function variants in , encoding the first step in the synthesis of PC, is the cause of a rostrocaudal muscular dystrophy in both humans and mice. Loss of sarcolemma integrity is a hallmark of muscular dystrophies; however, how this occurs in the absence of choline kinase function is not known.

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Article Synopsis
  • A rare case of preretinal granules was found in an 18-year-old male with atypical familial exudative vitreoretinopathy (FEVR), which had been observed since he was five years old.
  • The patient underwent genetic testing, but results showed no known pathogenic variants associated with FEVR, suggesting an unusual cause for his symptoms.
  • A literature review identified five similar cases, indicating that preretinal granules can occur in FEVR, prompting a need for further investigation into their origins and connections to retinal vascular anomalies.
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The impact of modern imaging in uncovering the underlying pathology of PMR cannot be understated. Long dismissed as an inflammatory syndrome with links to the large vessel vasculitis giant cell arteritis (GCA), a pathognomonic pattern of musculotendinous inflammation is now attributed to PMR and may be used to confirm its diagnosis. Among the available modalities, F-fluorodeoxyglucose (F-FDG) PET/CT is increasingly recognized for its high sensitivity and specificity, as well as added ability to detect concomitant large vessel GCA and exclude other relevant differentials like infection and malignancy.

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  • Achieving a proper diagnosis for Indigenous individuals with rare genetic diseases is essential for fair healthcare access.
  • The International Rare Disease Research Consortium has created a global Task Force aimed at addressing the challenges in diagnosing these rare diseases among Indigenous populations.
  • The initiative focuses on finding solutions to improve health equity for Indigenous communities dealing with these illnesses.
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It has been shown that atrial natriuretic peptide (ANP) and its high affinity receptor (NPRA) are involved in the formation of ventricular conduction system (VCS). Inherited genetic variants in fatty acid oxidation (FAO) genes are known to cause conduction abnormalities in newborn children. Although the effect of ANP on energy metabolism in noncardiac cell types is well documented, the role of lipid metabolism in VCS cell differentiation via ANP/NPRA signaling is not known.

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In Saccharomyces cerevisiae, the transcriptional repressor Opi1 regulates the expression of genes involved in phospholipid synthesis responding to the abundance of the phospholipid precursor phosphatidic acid at the endoplasmic reticulum. We report here the identification of the conserved leucine zipper (LZ) domain of Opi1 as a hot spot for gain of function mutations and the characterization of the strongest variant identified, Opi1. LZ modeling posits asparagine 150 embedded on the hydrophobic surface of the zipper and specifying dynamic parallel homodimerization by allowing electrostatic bonding across the hydrophobic dimerization interface.

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Janus kinase inhibitors (JAKi) have enormous appeal as immune-modulating therapies across many chronic inflammatory diseases, but recently this promise has been overshadowed by questions regarding associated cardiovascular and cancer risk emerging from the ORAL Surveillance phase 3b/4 post-marketing requirement randomized controlled trial. In that study of patients with rheumatoid arthritis with existing cardiovascular risk, tofacitinib, the first JAKi registered for chronic inflammatory disease, failed to meet non-inferiority thresholds when compared with tumor necrosis factor inhibitors for both incident major adverse cardiovascular events and incident cancer. While this result was unexpected by many, subsequently published observational data have also supported this finding.

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Objective: Diagnosing septic arthritis can be challenging and frequently involves clinical assessment, laboratory investigations and synovial fluid analysis. We sought to determine the utility of synovial aspiration and intra-operative synovial fluid and tissue culture for the accurate diagnosis of septic arthritis.

Methods: We carried out a retrospective review of the records of patients referred to a tertiary orthopaedic unit with possible septic arthritis between 2015 and 2019 inclusive, including clinical and laboratory data for this cohort study.

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Rheumatoid arthritis is an autoimmune condition that predominantly affects the synovial joints, causing joint destruction, pain, and disability. Historically, the standard for measuring the long-term efficacy of disease-modifying antirheumatic drugs has been the assessment of plain radiographs with scoring techniques that quantify joint damage. However, with significant improvements in therapy, current radiographic scoring systems may no longer be fit for purpose for the milder spectrum of disease seen today.

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The detection of adverse drug reactions (ADRs) is critical to our understanding of the safety and risk-benefit profile of medications. With an incidence that has not changed over the last 30 years, ADRs are a significant source of patient morbidity, responsible for 5%-10% of acute care hospital admissions worldwide. Spontaneous reporting of ADRs has long been the standard method of reporting, however this approach is known to have high rates of under-reporting, a problem that limits pharmacovigilance efforts.

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Objectives: To determine COVID-19 vaccine hesitancy rates in inflammatory arthritis patients and identify factors associated with changing vaccine hesitancy over time.

Methods: This investigation was a prospective cohort study of inflammatory arthritis patients from community and public hospital outpatient rheumatology clinics enrolled in the Australian Rheumatology Association Database (ARAD). Two surveys were conducted, one immediately prior to (pre-pandemic) and another approximately 1 year after the start of the pandemic (follow-up).

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Importance: Familial exudative vitreoretinopathy (FEVR) is a nonsyndromic autosomal dominant retinal disorder commonly caused by variants in the FZD4 gene. This study investigates the potential role beyond ocular abnormalities for FZD4 gene variants in patients with FEVR.

Objective: To evaluate the role of FZD4 in symptoms beyond those associated with FEVR through a patient with biallelic variants in FZD4.

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Deep learning has emerged as the leading method in machine learning, spawning a rapidly growing field of academic research and commercial applications across medicine. Deep learning could have particular relevance to rheumatology if correctly utilized. The greatest benefits of deep learning methods are seen with unstructured data frequently found in rheumatology, such as images and text, where traditional machine learning methods have struggled to unlock the trove of information held within these data formats.

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Article Synopsis
  • CHKB is a gene that codes for an enzyme crucial for producing phosphatidylcholine, a key component of cell membranes.
  • Inactivating this gene in mice leads to a type of muscular dystrophy, but intriguingly, levels of phosphatidylcholine don’t significantly change throughout the disease.
  • The study shows that affected muscles initially struggle to break down fatty acids for energy, which leads to an increase in fat storage; however, using specific treatments can help restore energy production and protect muscle cells from damage.
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The Kennedy pathways catalyse the de novo synthesis of phosphatidylcholine and phosphatidylethanolamine, the most abundant components of eukaryotic cell membranes. In recent years, these pathways have moved into clinical focus because four of ten genes involved have been associated with a range of autosomal recessive rare diseases such as a neurodevelopmental disorder with muscular dystrophy (CHKB), bone abnormalities and cone-rod dystrophy (PCYT1A) and spastic paraplegia (PCYT2, SELENOI). We identified six individuals from five families with bi-allelic variants in CHKA presenting with severe global developmental delay, epilepsy, movement disorders and microcephaly.

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The US Food and Drug Administration (FDA) has recently added a new 'black box warning' on all currently approved Janus kinase (JAK) inhibitors indicated for the treatment of arthritis and other inflammatory conditions based on results from the ORAL Surveillance study of tofacitinib versus tumour necrosis factor alpha inhibitors in rheumatoid arthritis. This is a warning difficult to ignore because the data, being from a randomised controlled trial, are of high fidelity and hard to reproach. It is especially problematic because safety data for all the other JAK inhibitors will be pending for several years.

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The CHKB gene encodes choline kinase β, which catalyzes the first step in the biosynthetic pathway for the major phospholipid phosphatidylcholine. Homozygous loss-of-function variants in human CHKB are associated with a congenital muscular dystrophy. Dilated cardiomyopathy is present in some CHKB patients and can cause heart failure and death.

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  • The final step of proline biosynthesis involves three enzymes, PYCR1, PYCR2, and PYCR3, which convert a compound called pyrroline-5-carboxylate into proline, with mutations in these genes linked to specific human diseases like Cutis Laxa and hypomyelinating leukodystrophy.
  • Research on mouse models revealed that Pycr1 mutations did not lead to any notable skin-related problems, whereas Pycr2 mutations resulted in neurological and neuromuscular symptoms, though peripheral nerves were mostly unaffected.
  • Both PYCR1 and PYCR2 show overlapping functions in proline metabolism, reinforcing that while they can compensate for each other's absence, a deficiency in either disrupts pro
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