Publications by authors named "Richard D Williams"

Big data present unprecedented opportunities to test long-standing theories regarding patterns and rates of geomorphic river adjustments. Here, we use locational probabilities derived from Landsat imagery (1988-2019) to quantify the dynamics of 600 km of riverbed in 10 Philippine catchments. Analysis of lateral adjustments reveals spatially non-uniform variability in along-valley patterns of geomorphic river mobility, with zones of relative stability interspersed with zones of relative instability.

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Background: Recent research elucidated the prognostic significance of molecular biology in Wilms tumor (WT) by linking somatic genomic variants (such as gain of chromosome 1q) to unfavorable patient outcomes. This analysis describes the clinical impact of copy number variations (CNV) in tumor samples of WT patients with stage IV disease.

Methods: Tumor samples of 55 WT patients with stage IV disease from the United Kingdom, France, and Germany enrolled in the SIOP 2001 study and treated with preoperative chemotherapy (pCHT) were examined for their CNVs of chromosome 1q and other regions of interest using multiplex ligation-dependent probe amplification (MLPA).

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Article Synopsis
  • - The study of Wilms tumour, which began with Alfred Knudson's 'two-hit' model, has advanced significantly over the last 50 years, leading to important discoveries in its genetics and biology.
  • - Research has focused on identifying prognostic biomarkers to improve treatment outcomes, although variability in these biomarkers within tumors creates challenges for individual patient care.
  • - Despite progress, ongoing investigations aim to deepen molecular understanding of Wilms tumour, including causes of relapse and bilateral cases, with international collaboration being key to addressing these complex issues.
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Quantitative descriptions of stream network and river catchment characteristics provide valuable context for enabling geomorphologically-informed sustainable river management. For countries where high-quality topographic data are available, there are opportunities to enable open access availability of baseline products from systematic assessment of morphometric and topographic characteristics. In this study, we present a national-scale assessment of fundamental topographic characteristics of Philippine river systems.

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Background: Wilms tumour (WT) survivors, especially patients with associated syndromes or genitourinary anomalies due to constitutional WT1 pathogenic variant, have increased risk of kidney failure. We describe the long-term kidney function in children with WT and WT1 pathogenic variant to inform the surgical strategy and oncological management of such complex children.

Methods: Retrospective analysis of patients with WT and constitutional WT1 pathogenic variant treated at a single centre between 1993 and 2016, reviewing genotype, phenotype, tumour histology, laterality, treatment, patient survival, and kidney outcome.

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River migration represents a geomorphic hazard at sites of critical bridge infrastructure, particularly in rivers where migration rates are high, as in the tropics. In the Philippines, where exposure to flooding and geomorphic risk are considerable, the recent expansion of infrastructural developments warrants quantification of river migration in the vicinity of bridge assets. We analysed publicly available bridge inventory data from the Philippines Department of Public Works and Highways (DPWH) to complete multi-temporal geospatial analysis using three decades worth of Landsat satellite imagery in Google Earth Engine (GEE).

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Case: An otherwise healthy 13-year-old girl presented with a firm nodule on the plantar right forefoot that was tender after cheerleading. Initial workup was unremarkable, but magnetic resonance imaging revealed a multilobulated mass surrounding the flexor hallucis longus tendon. Surgical resection revealed a tenosynovial mass without tendon infiltration.

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Results from the analysis of aqueous and solid-phase V speciation within samples collected from the Hazeltine Creek catchment affected by the August 2014 Mount Polley mine tailings dam failure in British Columbia, Canada, are presented. Electron microprobe and X-ray absorption near-edge structure (XANES) analysis found that V is present as V substituted into magnetite and V and V substituted into titanite, both of which occur in the spilled Mount Polley tailings. Secondary Fe oxyhydroxides forming in inflow waters and on creek beds have V K-edge XANES spectra exhibiting E1/2 positions and pre-edge features consistent with the presence of V species, suggesting sorption of this species on these secondary phases.

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Introduction: The International Society of Paediatric Oncology (SIOP) protocols recommend preoperative chemotherapy appropriate for Wilms tumors (WTs) in children with renal tumors aged ≥6 months, reserving biopsy for "atypical" cases. The Children's Cancer and Leukaemia Group (CCLG) joined the SIOP-WT-2001 study but continued the national practice of biopsy at presentation.

Method: Retrospective study of concordance between locally reported renal tumor biopsies and central pathology review nephrectomy diagnoses of children enrolled by CCLG centers in the SIOP-WT-2001 study.

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Background: Diffuse anaplastic Wilms tumor (DAWT) is a rare, high-risk subtype that is often missed on diagnostic needle biopsy. Somatic mutations in TP53 are associated with the development of anaplasia and with poorer survival, particularly in advanced-stage disease. Early identification of DAWT harboring TP53 abnormalities could improve risk stratification of initial therapy and monitoring for recurrence.

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Background: Nephrogenic rests (NRs) are abnormally persistent foci of embryonal cells, thought to be the precursor lesion of Wilms tumors (WTs). To date, their presence has not been systematically examined in WTs treated with preoperative chemotherapy.

Methods: A systematic analysis of the data on NRs in WTs treated with preoperative chemotherapy obtained from the UK cohort of the International Society of Pediatric Oncology (SIOP) WT 2001 Trial.

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Purpose: Wilms tumor (WT) is the most common pediatric renal tumor. Treatment planning under International Society of Paediatric Oncology (SIOP) protocols is based on staging and histologic assessment of response to preoperative chemotherapy. Despite high overall survival (OS), many relapses occur in patients without specific risk factors, and many successfully treated patients are exposed to treatments with significant risks of late effects.

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The evolution of pediatric solid tumors is poorly understood. There is conflicting evidence of intra-tumor genetic homogeneity vs. heterogeneity (ITGH) in a small number of studies in pediatric solid tumors.

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Objective: Heart failure is accompanied by up-regulation of transforming growth factor beta signaling, accumulation of collagen and dysregulation of sarcoplasmic reticulum calcium adenosine triphosphatase cardiac isoform 2a (SERCA2a). We examined the fibrotic response in small and large myocardial infarct, and the effect of overexpression of the SERCA2a gene.

Methods: Ischemic cardiomyopathy was induced via creation of large or small infarct in 26 sheep.

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Background: Wilms tumours (WTs) are characterised by several hallmarks that suggest epimutations such as aberrant DNA methylation are involved in tumour progression: loss of imprinting at 11p15, lack of recurrent mutations and formation of nephrogenic rests (NRs), which are lesions of retained undifferentiated embryonic tissue that can give rise to WTs.

Methods: To identify such epimutations, we performed a comprehensive methylome analysis on 20 matched trios of micro-dissected WTs, NRs and surrounding normal kidneys (NKs) using Illumina Infinium HumanMethylation450 Bead Chips and functionally validated findings using RNA sequencing.

Results: Comparison of NRs with NK revealed prominent tissue biomarkers: 629 differentially methylated regions, of which 55% were hypermethylated and enriched for domains that are bivalent in embryonic stem cells and for genes expressed during development (P = 2.

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Genomic gain of the proto-oncogene transcription factor gene MYCN is associated with poor prognosis in several childhood cancers. Here we present a comprehensive copy number analysis of MYCN in Wilms tumour (WT), demonstrating that gain of this gene is associated with anaplasia and with poorer relapse-free and overall survival, independent of histology. Using whole exome and gene-specific sequencing, together with methylation and expression profiling, we show that MYCN is targeted by other mechanisms, including a recurrent somatic mutation, P44L, and specific DNA hypomethylation events associated with MYCN overexpression in tumours with high risk histologies.

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Blastemal histology in chemotherapy-treated pediatric Wilms tumors (nephroblastoma) is associated with adverse prognosis. To uncover the underlying tumor biology and find therapeutic leads for this subgroup, we analyzed 58 blastemal type Wilms tumors by exome and transcriptome sequencing and validated our findings in a large replication cohort. Recurrent mutations included a hotspot mutation (Q177R) in the homeo-domain of SIX1 and SIX2 in tumors with high proliferative potential (18.

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Pathogenesis of heart diseases is associated with an altered expression profile of hundreds of genes. miRNAs are a newly identified layer of gene regulation operating at the post-transcriptional level by pairing to complementary base sequences in target mRNAs. Genetic data have identified the roles of miRNAs in basic pathological processes associated with heart failure: apoptosis, fibrosis, myocardial hypertrophy and cardiac remodeling.

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Purpose: The presence of diffuse anaplasia in Wilms tumours (DAWT) is associated with TP53 mutations and poor outcome. As patients receive intensified treatment, we sought to identify whether TP53 mutational status confers additional prognostic information.

Patients And Methods: We studied 40 patients with DAWT with anaplasia in the tissue from which DNA was extracted and analysed for TP53 mutations and 17p loss.

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Background: Wilms tumor is the most common pediatric renal malignancy and there is a clinical need for a molecular biomarker to assess treatment response and predict relapse. The known mutated genes in this tumor type show low mutation frequencies, whereas aberrant methylation at 11p15 is by far the most common aberration. We therefore analyzed the epigenome, rather than the genome, to identify ubiquitous tumor-specific biomarkers.

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Objective: Therapeutic safety and efficacy are the basic prerequisites for clinical gene therapy. We investigated the effect of high-dose molecular cardiac surgery with recirculating delivery (MCARD)-mediated adeno-associated virus 9 (AAV9)/sarcoplasmic reticulum Ca(2+) adenosine triphosphatase (SERCA2a) gene delivery on clinical parameters, oxidative stress, humoral and cellular immune responses, and cardiac remodeling.

Methods: Ischemic cardiomyopathy was generated in a sheep model.

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Background: Cardiac gene therapy for heart disease is a major translational research area with potential, yet problems with safe and efficient gene transfer into cardiac muscle remain unresolved. Existing methodology to increase vector uptake include modifying the viral vector, non-viral particle encapsulation and or delivery with device systems. These advanced methods have made improvements, however fail to address the key problem of inflammation in the myocardium, which is known to reduce vector uptake and contribute to immunogenic adverse events.

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Preclinical studies demonstrated the ability of an adenovirus/PSA (Ad/PSA) vaccine to induce strong anti-PSA immune responses, and these responses were capable of destroying prostate-specific antigen (PSA)-secreting mouse prostate tumors. A series of preclinical studies have demonstrated the superiority of the Ad/PSA vaccine to other PSA vaccines for the induction of anti-PSA immune responses, the ability of Ad/PSA vaccination combined with cytokine gene therapy and the TLR9 agonist CpG to enhance the anti-prostate tumor immunotherapy, and the reduction of negative regulatory elements when the vaccine was combined with 5-fluoruracil administration. A phase I clinical trial of the Ad/PSA vaccine in men with metastatic castrate-resistant prostate cancer demonstrated the safety of the vaccine even at the highest single dose permitted by the FDA.

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