170 research outputs found

    Crystallization behavior of iron- and boron-containing nepheline (Na2 O●Al2 O3 ●2SiO2 ) based model high-level nuclear waste glasses

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    This study focuses on understanding the relationship between iron redox, composition, and heat‐treatment atmosphere in nepheline‐based model high‐level nuclear waste glasses. Glasses in the Na2O–Al2O3–B2O3–Fe2O3–SiO2 system with varying Al2O3/Fe2O3 and Na2O/Fe2O3 ratios have been synthesized by melt‐quench technique and studied for their crystallization behavior in different heating atmospheres—air, inert (N2), and reducing (96%N2–4%H2). The compositional dependence of iron redox chemistry in glasses and the impact of heating environment and crystallization on iron coordination in glass‐ceramics have been investigated by Mössbauer spectroscopy and vibrating sample magnetometry. While iron coordination in glasses and glass‐ceramics changed as a function of glass chemistry, the heating atmosphere during crystallization exhibited minimal effect on iron redox. The change in heating atmosphere did not affect the phase assemblage but did affect the microstructural evolution. While glass‐ceramics produced as a result of heat treatment in air and N2 atmospheres developed a golden/brown colored iron‐rich layer on their surface, those produced in a reducing atmosphere did not exhibit any such phenomenon. Furthermore, while this iron‐rich layer was observed in glass‐ceramics with varying Al2O3/Fe2O3 ratio, it was absent from glass‐ceramics with varying Na2O/Fe2O3 ratio. An explanation of these results has been provided on the basis of kinetics of diffusion of oxygen and network modifiers in the glasses under different thermodynamic conditions. The plausible implications of the formation of iron‐rich layer on the surface of glass‐ceramics on the chemical durability of high‐level nuclear waste glasses have been discussed

    Grade of recurrent in situ and invasive carcinoma following treatment of pure ductal carcinoma in situ of the breast

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    Grade of recurrent in situ and invasive carcinoma following treatment of pure ductal carcinoma in situ of the breast The grade of recurrent in situ and invasive carcinoma occurring after treatment of pure ductal carcinoma in situ (DCIS) has been compared with the grade of the original DCIS in 122 patients from four different centres (The Royal Marsden Hospitals, London and Sutton, 57 patients; Guy's Hospital, London, 19 patients; Nottingham City Hospital, 31 patients and The Royal Liverpool Hospital, 15 patients). The recurrent carcinoma was pure DCIS in 70 women (57%) and in 52 women (43%) invasive carcinoma was present, which was associated with an in situ element in 43. In all, 19 patients developed a second recurrence (pure DCIS in 11 and invasive with or without an in situ element in eight). The majority of invasive carcinomas followed high-grade DCIS. There was strong agreement between the grade of the original DCIS and that of the recurrent DCIS (k = 0.679), which was the same in 95 of 113 patients (84%). The grade of the original DCIS showed only fair agreement with the grade of recurrent invasive carcinoma (k = 0.241), although agreement was stronger with the pleomorphism score of the recurrent carcinoma (k = 0.396). There was moderate agreement, in recurrent invasive lesions, between the grade of the DCIS and that of the associated invasive element (k = 0.515). Other features that showed moderate or strong agreement between the original and recurrent DCIS were necrosis and periductal inflammation. The similarity between the histological findings of the original and subsequent DCIS is consistent with the concept that recurrent lesions represent regrowth of residual carcinoma. In addition, although agreement between the grade of the original DCIS and that of any subsequent invasive carcinoma was only fair, there is no suggestion that low-grade DCIS lesions progress to higher grade lesions or to the development of higher grade invasive carcinoma. This is in agreement with immunohistochemical and molecular data indicating that low- grade and high-grade mammary carcinomas are quite different lesions

    Adenomyoepithelial tumours and myoepithelial carcinomas of the breast – a spectrum of monophasic and biphasic tumours dominated by immature myoepithelial cells

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    BACKGROUND: Adenomyoepithelial tumours and myoepithelial carcinomas of the breast are primarily defined by the presence of neoplastic cells with a myoepithelial immunophenotype. Current classification schemes are based on purely descriptive features and an assessment of individual prognosis is still problematic. METHODS: A series of 27 adenomyoepithelial tumours of the breast was analysed immunohistochemically with antibodies directed against various cytokeratins, p63, smooth muscle alpha-actin (SMA) and vimentin. Additionally, double immunofluorescence and comparative genomic hybridisation (CGH) was performed. RESULTS: Immunohistochemically, all the tumours showed a constant expression of high molecular weight cytokeratins (Ck) Ck5 and Ck14, p63, SMA and vimentin. With exception of one case diagnosed as myoepithelial carcinoma, all tested tumours expressed low molecular weight cytokeratin Ck18 in variable proportions of cells. Even in monophasic tumours lacking obvious glandular differentiation in conventional staining, a number of neoplastic cells still expressed those cytokeratins. Double immunofluorescence revealed tumour cells exclusively staining for Ck5/Ck14 in the presence of other cell populations that co-expressed high molecular weight Ck5/Ck14 as well as either low molecular weight Ck8/18 or SMA. Based on morphology, we assigned the series to three categories, benign, borderline and malignant. This classification was supported by a stepwise increase in cytogenetic alterations on CGH. CONCLUSION: Adenomyoepithelial tumours comprise a spectrum of neoplasms consisting of an admixture of glandular and myoepithelial differentiation patterns. As a key component SMA-positive cells co-expressing cytokeratins could be identified. Although categorisation of adenomyoepithelial tumours in benign, borderline and malignant was supported by results of CGH, any assessment of prognosis requires to be firmly based on morphological grounds. At present it is not yet clear, if and to what extent proposed Ck5-positive progenitor cells contribute to the immunohistochemical and morphological heterogeneity of these neoplasms of the breast

    Transcriptomic landscape of breast cancers through mRNA sequencing

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    Breast cancer is a heterogeneous disease with a poorly defined genetic landscape, which poses a major challenge in diagnosis and treatment. By massively parallel mRNA sequencing, we obtained 1.2 billion reads from 17 individual human tissues belonging to TNBC, Non-TNBC, and HER2-positive breast cancers and defined their comprehensive digital transcriptome for the first time. Surprisingly, we identified a high number of novel and unannotated transcripts, revealing the global breast cancer transcriptomic adaptations. Comparative transcriptomic analyses elucidated differentially expressed transcripts between the three breast cancer groups, identifying several new modulators of breast cancer. Our study also identified common transcriptional regulatory elements, such as highly abundant primary transcripts, including osteonectin, RACK1, calnexin, calreticulin, FTL, and B2M, and “genomic hotspots” enriched in primary transcripts between the three groups. Thus, our study opens previously unexplored niches that could enable a better understanding of the disease and the development of potential intervention strategies

    Classification of ductal carcinoma in situ by gene expression profiling

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    INTRODUCTION: Ductal carcinoma in situ (DCIS) is characterised by the intraductal proliferation of malignant epithelial cells. Several histological classification systems have been developed, but assessing the histological type/grade of DCIS lesions is still challenging, making treatment decisions based on these features difficult. To obtain insight in the molecular basis of the development of different types of DCIS and its progression to invasive breast cancer, we have studied differences in gene expression between different types of DCIS and between DCIS and invasive breast carcinomas. METHODS: Gene expression profiling using microarray analysis has been performed on 40 in situ and 40 invasive breast cancer cases. RESULTS: DCIS cases were classified as well- (n = 6), intermediately (n = 18), and poorly (n = 14) differentiated type. Of the 40 invasive breast cancer samples, five samples were grade I, 11 samples were grade II, and 24 samples were grade III. Using two-dimensional hierarchical clustering, the basal-like type, ERB-B2 type, and the luminal-type tumours originally described for invasive breast cancer could also be identified in DCIS. CONCLUSION: Using supervised classification, we identified a gene expression classifier of 35 genes, which differed between DCIS and invasive breast cancer; a classifier of 43 genes could be identified separating between well- and poorly differentiated DCIS samples

    Genetic variation in five genes important in telomere biology and risk for breast cancer

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    Telomeres, consisting of TTAGGG nucleotide repeats and a protein complex at chromosome ends, are critical for maintaining chromosomal stability. Genomic instability, following telomere crisis, may contribute to breast cancer pathogenesis. Many genes critical in telomere biology have limited nucleotide diversity, thus, single nucleotide polymorphisms (SNPs) in this pathway could contribute to breast cancer risk. In a population-based study of 1995 breast cancer cases and 2296 controls from Poland, 24 SNPs representing common variation in POT1, TEP1, TERF1, TERF2 and TERT were genotyped. We did not identify any significant associations between individual SNPs or haplotypes and breast cancer risk; however, data suggested that three correlated SNPs in TERT (−1381C>T, −244C>T, and Ex2-659G>A) may be associated with reduced risk of breast cancer among individuals with a family history of breast cancer (odds ratios 0.73, 0.66, and 0.57, 95% confidence intervals 0.53–1.00, 0.46–0.95 and 0.39–0.84, respectively). In conclusion, our data do not support substantial overall associations between SNPs in telomere pathway genes and breast cancer risk. Intriguing associations with variants in TERT among women with a family history of breast cancer warrant follow-up in independent studies

    Human and mouse essentiality screens as a resource for disease gene discovery.

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    The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines. We propose a cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. After screening developmental disorder cases from three independent disease sequencing consortia, we identify potentially pathogenic variants in genes not previously associated with rare diseases. We therefore propose FUSIL as an efficient approach for disease gene discovery

    Syndromics: A Bioinformatics Approach for Neurotrauma Research

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    Substantial scientific progress has been made in the past 50 years in delineating many of the biological mechanisms involved in the primary and secondary injuries following trauma to the spinal cord and brain. These advances have highlighted numerous potential therapeutic approaches that may help restore function after injury. Despite these advances, bench-to-bedside translation has remained elusive. Translational testing of novel therapies requires standardized measures of function for comparison across different laboratories, paradigms, and species. Although numerous functional assessments have been developed in animal models, it remains unclear how to best integrate this information to describe the complete translational “syndrome” produced by neurotrauma. The present paper describes a multivariate statistical framework for integrating diverse neurotrauma data and reviews the few papers to date that have taken an information-intensive approach for basic neurotrauma research. We argue that these papers can be described as the seminal works of a new field that we call “syndromics”, which aim to apply informatics tools to disease models to characterize the full set of mechanistic inter-relationships from multi-scale data. In the future, centralized databases of raw neurotrauma data will enable better syndromic approaches and aid future translational research, leading to more efficient testing regimens and more clinically relevant findings

    Genome-wide meta-analysis for Alzheimer's disease cerebrospinal fluid biomarkers

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    Amyloid-beta 42 (A beta 42) and phosphorylated tau (pTau) levels in cerebrospinal fluid (CSF) reflect core features of the pathogenesis of Alzheimer's disease (AD) more directly than clinical diagnosis. Initiated by the European Alzheimer & Dementia Biobank (EADB), the largest collaborative effort on genetics underlying CSF biomarkers was established, including 31 cohorts with a total of 13,116 individuals (discovery n = 8074; replication n = 5042 individuals). Besides the APOE locus, novel associations with two other well-established AD risk loci were observed; CR1 was shown a locus for A beta 42 and BIN1 for pTau. GMNC and C16orf95 were further identified as loci for pTau, of which the latter is novel. Clustering methods exploring the influence of all known AD risk loci on the CSF protein levels, revealed 4 biological categories suggesting multiple A beta 42 and pTau related biological pathways involved in the etiology of AD. In functional follow-up analyses, GMNC and C16orf95 both associated with lateral ventricular volume, implying an overlap in genetic etiology for tau levels and brain ventricular volume.Peer reviewe
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