186 research outputs found

    Identification of a Novel Genomic Island Associated with vanD-Type Vancomycin Resistance in Six Dutch Vancomycin-Resistant Enterococcus faecium Isolates

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    Genomic comparison of the first six Dutch vanD-type vancomycin-resistant Enterococcus faecium (VRE) isolates with four vanD gene clusters from other enterococcal species and anaerobic gut commensals revealed that the vanD gene cluster was located on a genomic island of variable size. Phylogenetic inferences revealed that the Dutch VRE isolates were genetically not closely related and that genetic variation of the vanD-containing genomic island was not species specific, suggesting that this island is transferred horizontally between enterococci and anaerobic gut commensals.Peer reviewe

    Quantifying effects of radiotherapy-induced microvascular injury; review of established and emerging brain MRI techniques

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    Microvascular changes are increasingly recognised not only as primary drivers of radiotherapy treatment response in brain tumours, but also as an important contributor to short- and long-term (cognitive) side effects arising from irradiation of otherwise healthy brain tissue. As overall survival of patients with brain tumours is increasing, monitoring long-term sequels of radiotherapy-induced microvascular changes in the context of their potential predictive power for outcome, such as cognitive disability, has become increasingly relevant. Ideally, radiotherapy-induced significant microvascular changes in otherwise healthy brain tissue should be identified as early as possible to facilitate adaptive radiotherapy and to proactively start treatment to minimise the influence on these side-effects on the final outcome. Although MRI is already known to be able to detect significant long-term radiotherapy induced microvascular effects, more recently advanced MR imaging biomarkers reflecting microvascular integrity and function have been reported and might provide a more accurate and earlier detection of microvascular changes. However, the use and validation of both established and new techniques in the context of monitoring early and late radiotherapy-induced microvascular changes in both target-tissue and healthy tissue currently are minimal at best. This review aims to summarise the performance and limitations of existing methods and future opportunities for detection and quantification of radiotherapy-induced microvascular changes, as well as the relation of these findings with key clinical parameters. (C) 2019 Elsevier B.V. All rights reserved

    Immune Phenotype and Function of Natural Killer and T Cells in Chronic Hepatitis C Patients Who Received a Single Dose of Anti-MicroRNA-122, RG-101

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    MicroRNA‐122 is an important host factor for the hepatitis C virus (HCV). Treatment with RG‐101, an N‐acetylgalactosamine‐conjugated anti‐microRNA‐122 oligonucleotide, resulted in a significant viral load reduction in patients with chronic HCV infection. Here, we analyzed the effects of RG‐101 therapy on antiviral immunity. Thirty‐two chronic HCV patients infected with HCV genotypes 1, 3, and 4 received a single subcutaneous administration of RG‐101 at 2 mg/kg (n = 14) or 4 mg/kg (n = 14) or received a placebo (n = 2/dosing group). Plasma and peripheral blood mononuclear cells were collected at multiple time points, and comprehensive immunological analyses were performed. Following RG‐101 administration, HCV RNA declined in all patients (mean decline at week 2, 3.27 log10 IU/mL). At week 8 HCV RNA was undetectable in 15/28 patients. Plasma interferon‐γ‐induced protein 10 (IP‐10) levels declined significantly upon dosing with RG‐101. Furthermore, the frequency of natural killer (NK) cells increased, the proportion of NK cells expressing activating receptors normalized, and NK cell interferon‐γ production decreased after RG‐101 dosing. Functional HCV‐specific interferon‐γ T‐cell responses did not significantly change in patients who had undetectable HCV RNA levels by week 8 post–RG‐101 injection. No increase in the magnitude of HCV‐specific T‐cell responses was observed at later time points, including 3 patients who were HCV RNA–negative 76 weeks postdosing. Conclusion: Dosing with RG‐101 is associated with a restoration of NK‐cell proportions and a decrease of NK cells expressing activation receptors; however, the magnitude and functionality of ex vivo HCV‐specific T‐cell responses did not increase following RG‐101 injection, suggesting that NK cells, but not HCV adaptive immunity, may contribute to HCV viral control following RG‐101 therapy

    Observation of an α-synuclein liquid droplet state and its maturation into Lewy body-like assemblies.

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    Misfolded α-synuclein is a major component of Lewy bodies, which are a hallmark of Parkinson's disease (PD). A large body of evidence shows that α-synuclein can aggregate into amyloid fibrils, but the relationship between α-synuclein self-assembly and Lewy body formation remains unclear. Here, we show, both in vitro and in a Caenorhabditis elegans model of PD, that α-synuclein undergoes liquid‒liquid phase separation by forming a liquid droplet state, which converts into an amyloid-rich hydrogel with Lewy-body-like properties. This maturation process towards the amyloid state is delayed in the presence of model synaptic vesicles in vitro. Taken together, these results suggest that the formation of Lewy bodies may be linked to the arrested maturation of α-synuclein condensates in the presence of lipids and other cellular components.Wellcome Trust (065807/Z/01/Z) (203249/Z/16/Z). Also, the UK Medical Research Council (MRC) (MR/K02292X/1), Alzheimer Research UK (ARUK) (ARUK-PG013-14), Michael J Fox Foundation (16238) and from Infinitus China Ltd

    Clinical relevance of the radiation dose bath in lower grade glioma, a cross-sectional pilot study on neurocognitive and radiological outcome

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    AIM: To investigate the clinical relevance of the radiotherapy (RT) dose bath in patients treated for lower grade glioma (LGG). METHODS: Patients (n = 17) treated with RT for LGG were assessed with neurocognitive function (NCF) tests and structural Magnetic Resonance Imaging (MRI) and categorized in subgroups based on tumour lateralisation. RT dose, volumetric results and cerebral microbleed (CMB) number were extracted for contralateral cerebrum, contralateral hippocampus, and cerebellum. The RT clinical target volume (CTV) was included in the analysis as a surrogate for focal tumour and other treatment effects. The relationships between RT dose, CTV, NCF and radiological outcome were analysed per subgroup. RESULTS: The subgroup with left-sided tumours (n = 10) performed significantly lower on verbal tests. The RT dose to the right cerebrum, as well as CTV, were related to poorer performance on tests for processing speed, attention, and visuospatial abilities, and more CMB. In the subgroup with right-sided tumours (n = 7), RT dose in the left cerebrum was related to lower verbal memory performance, (immediate and delayed recall, r = −0.821, p = 0.023 and r = −0.937, p = 0.002, respectively), and RT dose to the left hippocampus was related to hippocampal volume (r = −0.857, p = 0.014), without correlation between CTV and NCF. CONCLUSION: By using a novel approach, we were able to investigate the clinical relevance of the RT dose bath in patients with LGG more specifically. We used combined MRI-derived and NCF outcome measures to assess radiation-induced brain damage, and observed potential RT effects on the left-sided brain resulting in lower verbal memory performance and hippocampus volume

    Combined 1H-Detected solid-state NMR spectroscopy and electron cryotomography to study membrane proteins across resolutions in native environments

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    Membrane proteins remain challenging targets for structural biology, despite much effort, as their native environment is heterogeneous and complex. Most methods rely on detergents to extract membrane proteins from their native environment, but this removal can significantly alter the structure and function of these proteins. Here, we overcome these challenges with a hybrid method to study membrane proteins in their native membranes, combining high-resolution solid-state nuclear magnetic resonance spectroscopy and electron cryotomography using the same sample. Our method allows the structure and function of membrane proteins to be studied in their native environments, across different spatial and temporal resolutions, and the combination is more powerful than each technique individually. We use the method to demonstrate that the bacterial membrane protein YidC adopts a different conformation in native membranes and that substrate binding to YidC in these native membranes differs from purified and reconstituted system
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