148 research outputs found

    Wireless gas detection with a smartphone via rf communication

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    Chemical sensing is of critical importance to human health, safety, and security, yet it is not broadly implemented because existing sensors often require trained personnel, expensive and bulky equipment, and have large power requirements. This study reports the development of a smartphone-based sensing strategy that employs chemiresponsive nanomaterials integrated into the circuitry of commercial near-field communication tags to achieve non-line-of-sight, portable, and inexpensive detection and discrimination of gas-phase chemicals (e.g., ammonia, hydrogen peroxide, cyclohexanone, and water) at part-per-thousand and part-per-million concentrations.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (Contract W911NF-13-D-0001)Deshpande Center for Technological InnovationNational Institutes of Health (U.S.) (National Cancer Institute (U.S.) Ruth L. Kirschstein National Research Service Award F32CA157197

    Nipbl Interacts with Zfp609 and the Integrator Complex to Regulate Cortical Neuron Migration

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    Mutations in NIPBL are the most frequent cause of Cornelia de Lange syndrome (CdLS), a developmental disorder encompassin

    Neurogenin3 phosphorylation controls reprogramming efficiency of pancreatic ductal organoids into endocrine cells

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    β-cell replacement has been proposed as an effective treatment for some forms of diabetes, and in vitro methods for β-cell generation are being extensively explored. A potential source of β-cells comes from fate conversion of exocrine pancreatic cells into the endocrine lineage, by overexpression of three regulators of pancreatic endocrine formation and β-cell identity, Ngn3, Pdx1 and MafA. Pancreatic ductal organoid cultures have recently been developed that can be expanded indefinitely, while maintaining the potential to differentiate into the endocrine lineage. Here, using mouse pancreatic ductal organoids, we see that co-expression of Ngn3, Pdx1 and MafA are required and sufficient to generate cells that express insulin and resemble β-cells transcriptome-wide. Efficiency of β-like cell generation can be significantly enhanced by preventing phosphorylation of Ngn3 protein and further augmented by conditions promoting differentiation. Taken together, our new findings underline the potential of ductal organoid cultures as a source material for generation of β-like cells and demonstrate that post-translational regulation of reprogramming factors can be exploited to enhance β-cell generation

    Tracing the cellular basis of islet specification in mouse pancreas

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    Pancreatic islets play an essential role in regulating blood glucose level. Although the molecular pathways underlying islet cell differentiation are beginning to be resolved, the cellular basis of islet morphogenesis and fate allocation remain unclear. By combining unbiased and targeted lineage tracing, we address the events leading to islet formation in the mouse. From the statistical analysis of clones induced at multiple embryonic timepoints, here we show that, during the secondary transition, islet formation involves the aggregation of multiple equipotent endocrine progenitors that transition from a phase of stochastic amplification by cell division into a phase of sublineage restriction and limited islet fission. Together, these results explain quantitatively the heterogeneous size distribution and degree of polyclonality of maturing islets, as well as dispersion of progenitors within and between islets. Further, our results show that, during the secondary transition, α- and β-cells are generated in a contemporary manner. Together, these findings provide insight into the cellular basis of islet development

    Defining Lineage Potential and Fate Behavior of Precursors during Pancreas Development

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    Pancreas development involves a coordinated process in which an early phase of cell segregation is followed by a longer phase of lineage restriction, expansion, and tissue remodeling. By combining clonal tracing and whole-mount reconstruction with proliferation kinetics and single-cell transcriptional profiling, we define the functional basis of pancreas morphogenesis. We show that the large-scale organization of mouse pancreas can be traced to the activity of self-renewing precursors positioned at the termini of growing ducts, which act collectively to drive serial rounds of stochastic ductal bifurcation balanced by termination. During this phase of branching morphogenesis, multipotent precursors become progressively fate-restricted, giving rise to self-renewing acinar-committed precursors that are conveyed with growing ducts, as well as ductal progenitors that expand the trailing ducts and give rise to delaminating endocrine cells. These findings define quantitatively how the functional behavior and lineage progression of precursor pools determine the large-scale patterning of pancreatic sub-compartments

    Successful treatment of desmoid tumor of the chest wall with tranilast: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Desmoid tumor is characterized by infiltrative growth and local recurrence often occurs after surgery. To reduce the local recurrence rate, adjuvant therapy, such as radiotherapy and pharmacotherapy with cytotoxic agents, anti-estrogen agents and non-steroidal anti-inflammatory drugs, is often applied. In addition, these non-surgical treatments are also performed in patients with unresectable desmoid tumors. We successfully treated a patient with a desmoid tumor with tranilast; an anti-allergic agent.</p> <p>Case presentation</p> <p>A 48-year-old Japanese man with a slow-growing desmoid tumor on his chest wall was treated with an oral administration of tranilast (300 mg per day, three times a day). Two years and two months after the commencement of his therapy, the tumor became impalpable. At this time, the oral administration of tranilast was discontinued. Two years after discontinuation of the treatment, a physical examination showed no recurrence of the tumor and he continued in a state of remission. We were successfully able to reduce the size of the tumor and thereafter maintain the reduced size.</p> <p>Conclusion</p> <p>Tranilast was clinically effective in our case, and is probably comparable to cytotoxic agents or anti-estrogen agents. Because tranilast has substantially fewer adverse effects than cytotoxic agents, it could be a very useful therapeutic agent for desmoid tumor.</p

    Genome-Wide Analysis of Subependymomas Shows Underlying Chromosomal Copy Number Changes Involving Chromosomes 6, 7, 8 and 14 in a Proportion of Cases

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    Subependymomas (SE) are slow-growing brain tumors that tend to occur within the ventricles of middle-aged and elderly adults. The World Health Organization classifies these tumors within the ependymoma group. Previous limited analysis of this tumor type had not revealed significant underlying cytogenetic abnormalities

    Id4 and FABP7 are preferentially expressed in cells with astrocytic features in oligodendrogliomas and oligoastrocytomas

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    BACKGROUND: Oligodendroglioma (ODG) and oligoastrocytoma (OAC) are diffusely infiltrating primary brain tumors whose pathogenesis remains unclear. We previously identified a group of genes whose expression was inversely correlated with survival in a cohort of patients with glioblastoma (GBM), and some of these genes are also reportedly expressed in ODG and OAC. We examined the expression patterns and localization of these survival-associated genes in ODG and OAC in order to analyze their possible roles in the oncogenesis of these two tumor types. METHODS: We used UniGene libraries derived from GBM and ODG specimens to examine the expression levels of the transcripts for each of the 50 GBM survival-associated genes. We used immunohistochemistry and cDNA microarrays to examine expression of selected survival-associated genes and Id4, a gene believed to control the timing of oligodendrocyte development. The expression of FABP7 and Id4 and the survival of patients with ODG and OAC were also analyzed. RESULTS: Transcripts of most survival-associated genes as well as Id4 were present in both GBM and ODG tumors, whereas protein expression of Id4 and one of the survival-associated genes, brain-type fatty acid-binding protein (FABP7), was present in cells with astrocytic features, including reactive and neoplastic astrocytes, but not in neoplastic oligodendrocytes. Id4 was co-expressed with FABP7 in microgemistocytes in ODG and in neoplastic astrocytes in OAC. Id4 and FABP7 expression, however, did not correlate with the clinical outcome of patients with ODG or OAC tumors. CONCLUSION: Expression of Id4 and some of our previously identified GBM survival-associated genes is present in developing or mature oligodendrocytes. However, protein expression of Id4 and FABP7 in GBM, ODG, and OAC suggests that this group of functionally important genes might demonstrate two patterns of expression in these glioma subtypes: one group is universally expressed in glioma cells, and the other group of genes is expressed primarily in neoplastic astrocytes but not in neoplastic oligodendrocytes. Differential protein expression of these two groups of genes in ODG and OAC may be related to the cellular origins and the histological features of the neoplastic cells

    Multi-site Neurogenin3 Phosphorylation Controls Pancreatic Endocrine Differentiation

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    The proneural transcription factor Neurogenin3 (Ngn3) plays a critical role in pancreatic endocrine cell differentiation, although regulation of Ngn3 protein is largely unexplored. Here we demonstrate that Ngn3 protein undergoes cyclin-dependent kinase (Cdk)-mediated phosphorylation on multiple serine-proline sites. Replacing wild-type protein with a phosphomutant form of Ngn3 increases α cell generation, the earliest endocrine cell type to be formed in the developing pancreas. Moreover, un(der)phosphorylated Ngn3 maintains insulin expression in adult β cells in the presence of elevated c-Myc and enhances endocrine specification during ductal reprogramming. Mechanistically, preventing multi-site phosphorylation enhances both Ngn3 stability and DNA binding, promoting the increased expression of target genes that drive differentiation. Therefore, multi-site phosphorylation of Ngn3 controls its ability to promote pancreatic endocrine differentiation and to maintain β cell function in the presence of pro-proliferation cues and could be manipulated to promote and maintain endocrine differentiation in vitro and in vivo.This work was supported by the MRC Research GrantMR/K018329/1; the Rosetrees Trust (to A.P. and R.A.); the MRC Research Grant MR/L021129/1 and core support from the Wellcome Trust and the MRC Cambridge Stem Cell Institute (to A.P. and F.A.); the MRC Doctoral Training Awards (to L.M., L.H., and M.S.); the CRUK studentship (to C. Hurley); the Wellcome Trust 098357/Z/12/Z (to B.D.S. and R.A.); and the Wellcome Trust 097922/Z/11/Z and the Clinical Research Infrastructure Single-Cell Facility (MR/M008975/1) (to B.G.). D.W. and R.K. are CRUK funded; G.E. is CRUK A12077 funded. M.H. is a Sir Henry Dale fellow and is supported by the Wellcome Trust 104151/Z/14/A and the Royal Society
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