239 research outputs found
Nannotanyderus Ansorge 1994
No full textGenus <i>Nannotanyderus</i> Ansorge, 1994 <p> <i>Nannotanyderus</i> comprises five species in addition to the one described herein: <i>N. krzeminskii</i> Ansorge, 1994 from the Toarcian of Grimmen and Dobbertin, Germany; <i>N. grimmenensis</i> Ansorge & Krzemiński, 2002 from the Toarcian of Grimmen;? <i>N. incertus</i> Lukashevich, 2011 from the Upper Jurassic of Shar-Teg, Mongolia (this is based on an incomplete wing assigned to the genus with some reservation by the original author); <i>N. kubekovensis</i> Skibińska & Krzemiński, 2013 from the Upper Jurassic of Karatau, Kazakhstan (in Skibińska & Krzemiński, 2013 the specimen locality was incorrectly stated as Kubekovo); and <i>N. ansorgei</i> Krzemiński <i>et al</i>., 2013 from Lower Cretaceous Lebanese amber. Members of this genus are distinguished by their tiny size, with a wing length of 2–4 mm. Moreover vein Sc does not extend beyond the mid–point of the wing and vein R2 is several times shorter than R2+3.</p> <p> <b>Type species.</b> <i>Nannotanyderus krzeminskii</i> Ansorge, 1994; Lower Jurassic (Toarcian), Germany (Fig. 1).</p>Published as part of <i>Skibińska, Kornelia, Krzemiński, Wiesław & Coram, Robert A., 2014, Discovery of the most ancient member of family Tanyderidae (Diptera) from the Lower Jurassic (Sinemurian) of England, pp. 125-130 in Zootaxa 3857 (1)</i> on page 126, DOI: 10.11646/zootaxa.3857.1.6, <a href="http://zenodo.org/record/227424">http://zenodo.org/record/227424</a>
Tocilizumab-associated multifocal cerebral thrombotic microangiopathy
No full textTocilizumab is a humanized monoclonal antibody that targets the interleukin-6 receptor (IL-6-R). It is approved for use in moderate to severe refractory rheumatoid arthritis and more recently has been found to be effective in treating neuromyelitis optica.1 Common side effects include raised hepatic transaminases, gastroenteritis, infections, and hypertension. Neurologic side effects have been described in 2 single case reports, which were confounded by the concomitant use of other antirheumatic therapies and lengthy durations between tocilizumab administration and onset of neurologic symptoms.,3 We describe the clinico-histologic analysis of an acute neurologic deterioration 2 weeks after the first infusion of tocilizumab
A macroprolactinoma becoming resistant to cabergoline and developing atypical pathology
No full textPituitary adenomas are a common intracranial neoplasm, usually demonstrating a benign phenotype. They can be classified according to pathological, radiological or clinical behaviour as typical, atypical or carcinomas, invasive
or noninvasive, and aggressive or nonaggressive. Prolactinomas account for 40–60% of all pituitary adenomas,\ud
with dopamine agonists representing the first-line treatment and surgery/radiotherapy reserved for drug intolerance/resistance or in neuro-ophthalmological emergencies. We present the case of a 62-year-old man with an apparently indolent prolactin-secreting macroadenoma managed with partial resection and initially showing a biochemical response to cabergoline. Five years later, the tumour became resistant to cabergoline, despite a substantial increase in dosage, showing rapid growth and causing worsening of vision. The patient then underwent two further transsphenoidal operations and continued on high-dose cabergoline; despite these interventions, the tumour continued enlarging and prolactin increased to 107 269 U/L. Histology of the third surgical specimen demonstrated features of aggressive behaviour (atypical adenoma with a high cell proliferation index) not present
in the tumour removed at the first operation. Subsequently, he was referred for radiotherapy aiming to control tumour growth
Post-mortem QSM and R2* maps
No full textThis repository contains data associated with the following publication:
Methods for quantitative susceptibility and R2* mapping in whole post-mortem brains at 7T applied to amyotrophic lateral sclerosis
Authors: Chaoyue Wang, Sean Foxley, Olaf Ansorge, Sarah Bangerter-Christensen, Mark Chiew, Anna Leonte, Ricarda A.L. Menke, Jeroen Mollink, Menuka Pallebage-Gamarallage, Martin R. Turner, Karla L. Miller*, Benjamin C. Tendler* (* indicates equal contribution)
The text file dataset_loc_QSM_R2s.txt contains a link to the dataset. Further information about the dataset can be found in dataset_info.txt and the publication
Selective vulnerability of the primary motor cortex in amyotrophic lateral sclerosis
No full textThe âselective vulnerabilityâ of cells and systems to disease pathomechanisms is a defining feature of amyotrophic lateral sclerosis (ALS), where the relative clinical and pathological involvement of cortical motor neurons varies between patients. Mislocalisation and aggregation of hyperphosphorylated TDP-43 (pTDP-43) is the major neuropathological finding in the majority of ALS cases (ALS-TDP), however the relationship between TDP-43 aggregation and neurodegeneration remains unclear. Here, we sought to reconcile the selective vulnerability of specific cell types within the human primary motor cortex to the pathological hallmarks of ALS, and define commonalities and differences of neurodegenerative phenotypes across the genetic spectrum of the disease. We analysed human post-mortem tissue from a large cohort of genetically defined ALS/FTD (n = 78), and mean age-matched control cases (n = 15) using a combination of quantitative immunohistochemical techniques and multi-level generalized linear modelling. The utility of novel methods such as CLARITY, imaging mass cytometry, combined RNA-ISH/IHC and multiplexed immunofluorescence is also explored. Additionally, two monogenic forms of the disease which exhibit striking UMN/LMN predominance, ALS-FUS and ALS-OPTN, are discussed and compared in the context of a novel BAC transgenic mouse and a unique human index case.
We show that there is considerable variance in neuropathology within the ALS primary motor cortex both within and across the genetic spectrum of disease, including in pTDP-43 aggregation, microglial activation, and inhibitory interneuron number. We also assess the extent of this pathology across the corticospinal neuraxis, and begin to examine the interactive relationship of pathologies using multiplexed immunofluorescence. Using RNA-ISH, we also show that while FUS is significantly more highly expressed in the primary motor cortex, TARDBP demonstrates a higher retention of transcripts localised to the nucleus. We also begin to assess the expression of transcription factors associated with projection neuron diversity including CTIP2, SATB2 and TBR1 in the primary motor cortex. Broadly, this thesis refines the concept of selective vulnerability within the ALS motor cortex across genetic subtypes, whilst highlighting the distinction between cellular vulnerability to proteinopathy and vulnerability to degeneration itself. These findings have implications for our understanding of disease pathogenesis and the development of genotype-specific therapies.</p
Proteomics and Transcriptomics of the Betz cell in the Human Brain.
No full textVery little is known about the enigmatic gigantopyramidal neuron in the Primary Motor Cortex. These Betz cells are the largest neurons in the human brain, display unique morphology, play a fundamental role in voluntary movement, and are selectively vulnerable to a range of neurodegenerative diseases, including Amyotrophic Lateral Sclerosis (ALS). Yet, there has been no targeted studies to investigate the molecular profile of these neurons and how that may be affected in disease. Here, for the first time, laser microdissected human Betz cells were subjected to extensive proteomic analysis via a workflow that has been optimised to produce leading proteomic performance from individually pooled neurons. The proteome of the Betz cell has been comparatively analysed to similar neurons to reveal key insights into their physiology. This thesis molecularly confirms previous assumptions about their biology and discovers cellular mechanisms that are enriched within these neurons. To complement proteomic findings, laser microdissected Betz cells were also subjected to RNA-sequencing to investigate their gene expression patterns, to validate recently generated proteomic observations, and for the first time, to reveal the transcriptome of the Betz cell. To ease and improve future Betz cell research, the proteomic/transcriptomic data were screened to search for Betz cells biomarkers – for which there are currently none that immunochemically target Betz cells without also binding to surrounding neurons. Several proteins were identified that could selectively target Betz cells, potentially acting Betz cell biomarkers. Finally, proteomic/transcriptomic analysis was also applied to microdissected Betz cells from ALS patients to determine how/why these neurons degenerate in ALS. The findings herein, align with the excitotoxicity hypothesis of ALS, i.e. that upper motor neurons become over-activated by excess glutamate activity. These data also provide clues to other pathways that may cause the degeneration of Betz cells in ALS e.g. DNA damage, oxidative stress, dysregulated energy production, and impaired axonal guidance
Functional analysis of the ALS/FTD associated gene FUS using a novel in vitro genomic DNA expression system
No full textAggregations of fused in sarcoma (FUS), a multifunctional RNA processing protein, define a pathological subtype of both frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), whilst mutations in the FUS gene are causative for ALS. To model the impact of FUS mutations, expression vectors containing the entire genomic sequence of FUS, up and downstream regions, and native promoter sequences have been generated. The constructs have been tagged with an mCherry fluorescent tag, and three separate pathological mutations (R244C, R521C, and P525L) have been separately inserted. Transgenic mice have been generated using the WT and P525L FUS vectors to provide a highly physiological model of FUS in disease. Within transfected HEK293 cells, insertion of the P525L and R521C FUS mutations leads to relocalisation of FUS from the nucleus to the cytoplasm. R521C and P525L mutant FUS incorporates into cytoplasmic aggregations of untranslated mRNA and RNA binding proteins known as stress granules. The strong relocalisation seen with P525L-FUS is associated with a gain of cytotoxicity. Reversal of this cytoplasmic relocalisation by demethylation of FUS rescues this cytotoxicity, suggesting a toxic gain of cytoplasmic function in the majority of FUS mutations. By contrast, insertion of the R244C mutation leads to neither relocalisation, stress granule association, nor cytotoxicity. Notably the R244C mutation, located away from the nuclear localization domain in which the majority of FUS mutations are found, leads to the presence of smaller FUS fragments in western blot analyses. These fragments appear not to be due to splicing defects in FUS but rather are due to post-translational modifications or aberrant protein cleavage. These data suggest an alternative pathway for FUS toxicity based upon a nuclear loss of function
The neuropathological approach to the diagnosis of brain tumours
No full textThis review provides an introduction to the concepts and practical aspects concerning the diagnosis of neoplasms involving the brain. Principles of the WHO classification are described, including concepts of lineage origin of brain tumours and aetiology (environment versus genetic predisposition). The importance of neuroimaging in the context of the intraoperative diagnostic approach and formulation of differential diagnoses is emphasized. A brief overview of immunohistochemical markers is provided. Common cytological and architectural patterns are illustrated with educational case material. © 2011
Spatially resolved proteomics of a human brain tumour
No full textBiological tissues contain diverse cell subpopulations crucial to their function, and proteins are the macromolecules that carry out many of these functions. Robust mass spectrometry-based methods that can accurately identify and quantify thousands of proteins within a sample have transformed the investigation of protein abundance and function within tissues and cells. However, mass spectrometry-based proteomics of tissue is traditionally performed on bulk samples. Therefore, information on the spatial composition and protein abundance patterns of those tissues is lost. Currently, the spatial context of proteins within a tissue is investigated using antibody-based high-resolution techniques with little multiplexing capacity.
There is a clear need for techniques that generate unbiased, quantitative, spatial expression profiles of many hundreds to thousands of proteins within a tissue. Presented within this thesis is the development of sample preparation, acquisition, and analysis workflows for spatially resolved proteomics using bottom-up mass spectrometry. This method was used to analyse an atypical teratoid/rhabdoid tumour (ATRT), a rare paediatric brain tumour.
Firstly, an optimised workflow was developed and used to characterise the proteomes of two neurons: Betz and Purkinje cells. Both cell types show highly specific proteomes. Purkinje cells show an increased abundance of several known Purkinje cell marker proteins. In addition, several novel candidate marker proteins for Betz cells were identified.
Secondly, the method was extended to allow for unbiased sampling of tissue in a spatially resolved manner. The method shows clear signals from a starting material of approximately 50 cells isolated from ATRT tissue. Analysis of the data within the tissue’s spatial context highlights proteins and pathways showing spatially variable abundance within the tumour and adjacent normal tissue. This is performed without prior knowledge of the tissue composition by using spatially aware statistical methods.
Finally, orthogonal validation was performed using immunohistochemistry and mass spectrometry imaging which recapitulates the spatial variability observed in the bottom-up mass spectrometry approach.
Overall, the work presented here informs on methods for spatially resolved proteomics of tissue, laying the groundwork for further spatially resolved tissue proteomics and highlighting the utility of such approaches to understanding tissue biology
Genomics of human pituitary neuroendocrine tumours
No full textPituitary neuroendocrine tumours (PitNETs) are the second most common type of intra-cranial tumour with a prevalence of 96 cases per 100,000. PitNETs arise from neuroendocrine hormone secreting cells and are associated clinical manifestations that affect both the site of origin and the entire body. Despite all this, PitNET molecular biology and pathogenesis is still poorly understood.
Improvements in high throughput sequencing over the past two decades have made genome sequencing, RNA sequencing and methylomics faster, cheaper and more readily available. Yet, the bioinformatic analysis and interpretation of data remains inherently complex. One key challenge is identifying novel pathogenic variants against the backdrop of intraspecies genome variability. This challenge is further compounded in tumour or cancer samples due to genomic instability.
In this thesis, I first implemented a new approach for downstream variant annotation for single nucleotide variant (SNV) and structural variant (SV) analysis using multiple annotation tools including Ensembl Variant Effect Predictor (VEP), Genomics England Tiering Application and AnnotSV, to determine high confidence variants. To enable reliable downstream pathway analysis, high confidence variants were then evaluated using the COSMIC Cancer Gene Census, Reactome, and STRING databases. This method of downstream annotation was applied to whole exome genome sequencing data, short read whole genome sequencing data (srWGS) and long read whole genome sequencing data (lrWGS) data post-variant calling, with standardised procedures developed by Genomics England for each sequencing platform. However, the downstream annotation pipeline developed and implemented in this project could be applied to the variant call data for each sequencing platform.
For the SNV analysis in PitNETs, this study found pathogenic variants in genes such as ATM, ATRX, BRCA2, FGFR4, GNAS, IDH1, PDE4DIP and PTEN. For the limited number of samples that underwent both srWGS and lrWGS, validation of srWGS somatic variant findings is reported, and the discovery of certain variants not detected by srWGS but identified by lrWGS such as NFKB2 and IDH2.
For structural variant analysis in PitNETs, I report finding SV changes to the genes ATM, ATRX, FGFR gene family, GNAS and RAF1. The downstream annotation findings from srWGS were also discovered in lrWGS data and IGV visual analysis, in samples which underwent both sequencing modalities.
From our SNV and SV findings we report extensive involvement of the PI3K/AKT/mTOR pathway in PitNET pathogenesis, raising the possibility of targeting this pathway with mTOR inhibitors for future patient therapy. The results for SNV and SV analysis, suggest that annotation of variants calls from samples with multiple tools could be a feasible strategy to identify high confidence variants to enable bioinformaticians to make sense of data.
Second, RNA sequence analysis was conducted on a cohort of somatotroph PitNETs. These growth hormone secreting PitNETs, were of a particular interest in this study, as there are two types; sparsely and densely granulated PitNETs. To date, there is no known unique molecular signature to distinguish these two somatotroph PitNET subtypes. From RNA Sequence analysis, I report changes to the growth hormone receptor signalling pathway.
Third, methylomics analysis was conducted with EPIC Chip 450K data for the same group of PitNETs that underwent RNA sequencing. For, this cohort, similarities in the global methylation profile of the two somatotroph PitNET types are reported. Integrated analysis of RNA-Sequencing data and EPIC Chip methylomics data was then performed. Visualization of this data revealed no distinct molecular signature between the two somatotroph PitNET subtypes.
Finally, Oxford Nanopore Long Read Sequence Methylomics data was studied for PitNETs. This cohort included two gonadotroph PitNETs, one of which contained an IDH1 SNV variant. Despite the presence of this IDH1 variant, similar methylation profiles between the two tumour samples. A comparison of these gonadotroph PitNETs with other PitNET types revealed gonadotroph PitNETs to have a hypermethylation profile, in respect to other PitNET types. Thus, it is hypothesized that the hypermethylation profile of gonadotroph PitNETs may play a role in their non-secretory phenotype
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