Publications by authors named "Samueel P de Visser"

The ease with which genome-wide data can nowadays be collected allows complicated phylogenetic questions to be re-evaluated. Phylogenetic relationships among newts have often proven difficult to resolve due to the prevalence of incomplete lineage sorting and introgressive hybridization. For the newt genus Lissotriton, phylogenetic relationships are not settled and there is controversy surrounding the species status of several taxa.

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Background: Early intervention in psychosis (EIP) services improve outcomes for young people, but approximately 30% disengage.

Aims: To test whether a new motivational engagement intervention would prolong engagement and whether it was cost-effective.

Method: We conducted a multicentre, single-blind, parallel-group, cluster randomised controlled trial involving 20 EIP teams at five UK National Health Service (NHS) sites.

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Background: Autoantibodies are found in up to 80 % of patients with idiopathic inflammatory myopathies (IIM) and are associated with distinct clinical phenotypes. Autoantibodies targeting cytosolic 5'-nucleotidase 1A (anti-NT5C1A) are currently the only known serum biomarker for the subgroup inclusion body myositis (IBM), although detected even in other autoimmune diseases. The aim of the study was to identify new autoimmune targets in IIM.

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Resolving the order of speciation events that occurred in rapid succession is inherently hard and typically requires a phylogenomic approach. A case in point concerns the previously unresolved phylogeny of the three species of banded newt (genus Ommatotriton). We obtain c.

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During gliotoxin biosynthesis in fungi, the cytochrome P450 GliF enzyme catalyzes an unusual C-N ring-closure step while also an aromatic ring is hydroxylated in the same reaction cycle, which may have relevance to drug synthesis reactions in biotechnology. However, as the details of the reaction mechanism are still controversial, no applications have been developed yet. To resolve the mechanism of gliotoxin biosynthesis and gain insight into the steps leading to ring-closure, we ran a combination of molecular dynamics and density functional theory calculations on the structure and reactivity of P450 GliF and tested a range of possible reaction mechanisms, pathways and models.

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Article Synopsis
  • The study aimed to analyze how damage from idiopathic inflammatory myopathies (IIM) changes over time and its relationship with different autoantibody subgroups using data from a large patient registry.
  • Researchers examined data from 757 patients classified by their autoantibody profiles and found that damage increased over the years, with varying rates depending on the type of autoantibody present.
  • Results indicated that patients with dermatomyositis-specific autoantibodies exhibited less damage per year, while those with anti-PM/Scl autoantibodies experienced greater damage, highlighting significant differences among the groups over a five-year follow-up.
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The cytochrome P450 homolog, TxtE, efficiently catalyzes the direct and regioselective aromatic nitration of the indolyl moiety of L-tryptophan to 4-nitro-L-tryptophan, using nitric oxide (NO) and dioxygen (O) as co-substrates. Pathways for such direct and selective nitration of heteroaromatic motifs present platforms for engineering new nitration biocatalysts for pharmacologically beneficial targets, among a medley of other pivotal industrial applications. Precise mechanistic details concerning this pathway are only weakly understood, albeit a heme iron(III)-peroxynitrite active species has been postulated.

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Cannabidiol (CBD), the main non-intoxicating compound in cannabis, has been hypothesized to reduce the adverse effects of Δ-tetrahydrocannabinol (THC), the main psychoactive and analgesic component of cannabis. This clinical trial investigated the hypothesis that CBD counteracts the adverse effects of THC and thereby potentially improves the tolerability of cannabis as an analgesic. A randomized, double-blind, placebo-controlled, five-way cross-over trial was performed in 37 healthy volunteers.

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Using machine learning, molecular dynamics simulations, and density functional theory calculations we gain insight into the selectivity patterns of substrate activation by the cytochromes P450. In nature, the reactions catalyzed by the P450s lead to the biodegradation of xenobiotics, but recent work has shown that fungi utilize P450s for the activation of lignin fragments, such as monomer and dimer units. These fragments often are the building blocks of valuable materials, including drug molecules and fragrances, hence a highly selective biocatalyst that can produce these compounds in good yield with high selectivity would be an important step in biotechnology.

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The nature of the axial ligand in high-valent iron-oxo heme enzyme intermediates and related synthetic catalysts is a critical structural element for controlling proton-coupled electron-transfer (PCET) reactivity of these species. Herein, we describe the generation and characterization of three new 6-coordinate, iron(IV)-oxo porphyrinoid-π-cation-radical complexes and report their PCET reactivity together with a previously published 5-coordinate analogue, Fe(O)(TBPCz) (TBPCz = octakis(--butylphenyl)corrolazinato) () (Cho, K. A high-valent iron-oxo corrolazine activates C-H bonds via hydrogen-atom transfer.

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Lysine dioxygenase (KDO) is an important enzyme in human physiology involved in bioprocesses that trigger collagen cross-linking and blood pressure control. There are several KDOs in nature; however, little is known about the factors that govern the regio- and stereoselectivity of these enzymes. To understand how KDOs can selectively hydroxylate their substrate, we did a comprehensive computational study into the mechanisms and features of 4-lysine dioxygenase.

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Transforming CO into valuable materials is an important reaction in catalysis, especially because CO concentrations in the atmosphere have been growing steadily due to extensive fossil fuel usage. From an environmental perspective, reduction of CO to valuable materials should be catalyzed by an environmentally benign catalyst and avoid the use of heavy transition-metal ions. In this work, we present a computational study into a novel iron(I) porphyrin catalyst for CO reduction, namely, with a tetraphenylporphyrin ligand and analogues.

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The Consolidated Standards of Reporting Trials extension for Artificial Intelligence interventions (CONSORT-AI) was published in September 2020. Since its publication, several randomised controlled trials (RCTs) of AI interventions have been published but their completeness and transparency of reporting is unknown. This systematic review assesses the completeness of reporting of AI RCTs following publication of CONSORT-AI and provides a comprehensive summary of RCTs published in recent years.

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European marbled newts come in two species that have abutting ranges. The northern species, Triturus marmoratus, is found in France and the northern part of the Iberian Peninsula, whereas the southern species, T. pygmaeus, is found in the southwestern corner of the Iberian Peninsula.

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Background: There are few prospective studies of factors that mediate the association between exposure to adverse childhood experiences (ACEs) and obesity in adolescence. Our aim was to address this limitation.

Methods: We used prospective data from the Growing up in Ireland cohort study, with measurements at 9, 13, and 18 years old.

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Cytochrome P450 enzymes in the human body play a pivotal role in both the biosynthesis and the degradation of the hormone melatonin. Melatonin plays a key role in circadian rhythms in the body, but its concentration is also linked to mood fluctuations as well as emotional well-being. In the present study, we present a computational analysis of the binding and activation of melatonin by various P450 isozymes that are known to yield different products and product distributions.

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Nitrogenase is a fascinating enzyme in biology that reduces dinitrogen from air to ammonia through stepwise reduction and protonation. Despite it being studied in detail by experimental and computational groups, there are still many unknown factors in the catalytic cycle of nitrogenase, especially related to the addition of protons and electrons and their order. A recent biomimetic study characterized a potential dinitrogen-bridged diiron cluster as a synthetic model of nitrogenase.

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Invasive lobular breast cancer (ILC) is the second most common histological breast cancer subtype, but ILC-specific trials are lacking. Translational research revealed an immune-related ILC subset, and in mouse ILC models, synergy between immune checkpoint blockade and platinum was observed. In the phase II GELATO trial ( NCT03147040 ), patients with metastatic ILC were treated with weekly carboplatin (area under the curve 1.

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In the last two decades, antisense oligonucleotides (AONs) that induce corrective exon skipping have matured as promising therapies aimed at tackling the dystrophin deficiency that underlies the severe and progressive muscle fiber degeneration in Duchenne muscular dystrophy (DMD) patients. Pioneering first generation exon 51 skipping AONs like drisapersen and eteplirsen have more recently been followed up by AONs for exons 53 and 45, with, to date, a total of four exon skipping AON drugs having reached (conditional) regulatory US Food and Drug Administration (FDA) approval for DMD. Nonetheless, considering the limited efficacy of these drugs, there is room for improvement.

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Article Synopsis
  • The study investigates whether mindfulness-based cognitive therapy self-help (MBCT-SH) is more effective than cognitive behavioral therapy self-help (CBT-SH) in reducing depressive symptoms over 16 weeks for adults with mild to moderate depression.
  • It involved a randomized clinical trial with 410 participants, who were divided into two groups receiving either MBCT-SH or CBT-SH, along with support sessions from trained practitioners.
  • The primary outcome measured was the reduction in depressive symptoms using the Patient Health Questionnaire (PHQ-9) score, with analysis focused on intentional treatment effects.
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Caffeine is a natural compound found in plant seeds that after consumption by humans effects the central nervous system as well as the cardiovascular system. In general, the cytochrome P450 enzymes in the liver are involved in the biodegradation of caffeine, which gives paraxanthine, theobromine and theophylline products. There has been debate for many years why multiple products are obtained and how their distributions are determined.

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Anoctamin-5 related muscle disease is caused by biallelic pathogenic variants in the anoctamin-5 gene (ANO5) and shows variable clinical phenotypes: limb-girdle muscular dystrophy type 12 (LGMD-R12), distal muscular dystrophy type 3 (MMD3), pseudometabolic myopathy or asymptomatic hyperCKaemia. In this retrospective, observational, multicentre study we gathered a large European cohort of patients with ANO5-related muscle disease to study the clinical and genetic spectrum and genotype-phenotype correlations. We included 234 patients from 212 different families, contributed by 15 centres from 11 European countries.

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Objectives: Dedicated PICUs are slowly starting to emerge in sub-Saharan Africa. Establishing these units can be challenging as there is little data from this region to inform which populations and approaches should be prioritized. This study describes the characteristics and outcome of patients admitted to the first PICU in Malawi, with the aim to identify factors associated with increased mortality.

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Cytochrome P450 enzymes are versatile enzymes found in most biosystems that catalyze mono-oxygenation reactions as a means of biosynthesis and biodegradation steps. In the liver, they metabolize xenobiotics, but there are a range of isozymes with differences in three-dimensional structure and protein chain. Consequently, the various P450 isozymes react with substrates differently and give varying product distributions.

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Bisphenol A (BPA, 2,2-bis-(4-hydroxyphenyl)propane) is used as a precursor in the synthesis of polycarbonate and epoxy plastics; however, its availability in the environment is causing toxicity as an endocrine-disrupting chemical. Metabolism of BPA and their analogues (substitutes) is generally performed by liver cytochrome P450 enzymes and often leads to a mixture of products, and some of those are toxic. To understand the product distributions of P450 activation of BPA, we have performed a computational study into the mechanisms and reactivities using large model structures of a human P450 isozyme (P450 2C9) with BPA bound.

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