2,248 research outputs found
Phosphorylation of pRb: mechanism for RB pathway inactivation in MYCN-amplified retinoblastoma.
A small, but unique subgroup of retinoblastoma has been identified with no detectable mutation in the retinoblastoma gene (RB1) and with high levels of MYCN gene amplification. This manuscript investigated alternate pathways of inactivating pRb, the encoded protein in these tumors. We analyzed the mutation status of the RB1 gene and MYCN copy number in a series of 245 unilateral retinoblastomas, and the phosphorylation status of pRb in a subset of five tumors using immunohistochemistry. There were 203 tumors with two mutations in RB1 (RB1(-/-) , 83%), 29 with one (RB1(+/-) , 12%) and 13 with no detectable mutations (RB1(+/+) , 5%). Eighteen tumors carried MYCN amplification between 29 and 110 copies: 12 had two (RB1(-/-) ) or one RB1 (RB1(+/-) ) mutations, while six had no mutations (RB1(+/+) ). Immunohistochemical staining of tumor sections with antibodies against pRb and phosphorylated Rb (ppRb) displayed high levels of pRb and ppRb in both RB1(+/+) and RB1(+/-) tumors with MYCN amplification compared to no expression of these proteins in a classic RB1(-/-) , MYCN-low tumor. These results establish that high MYCN amplification can be present in retinoblastoma with or without coding sequence mutations in the RB1 gene. The functional state of pRb is inferred to be inactive due to phosphorylation of pRb in the MYCN-amplified retinoblastoma without coding sequence mutations. This makes inactivation of RB1 by gene mutation or its protein product, pRb, by protein phosphorylation, a necessary condition for initiating retinoblastoma tumorigenesis, independent of MYCN amplification
Agouti C57BL/6N embryonic stem cells for mouse genetic resources.
We report the characterization of a highly germline competent C57BL/6N mouse embryonic stem cell line, JM8. To simplify breeding schemes, the dominant agouti coat color gene was restored in JM8 cells by targeted repair of the C57BL/6 nonagouti mutation. These cells provide a robust foundation for large-scale mouse knockout programs that aim to provide a public resource of targeted mutations in the C57BL/6 genetic background
Characterization of polyoxometalate I as an inhibitor of RNA-dependent RNA polymerase of Foot and Mouth Disease virus [abstract]
Abstract only availableFoot and Mouth Disease (FMD) is a highly contagious disease that affects a variety of domesticated cloven-hoofed animals including cattle, swine, sheep and goats, as well as several wild animal species. FMD outbreaks are currently controlled with mass-extermination of livestock. The financial cost of potential outbreaks would be immense. This disease is caused by foot-and-mouth disease virus (FMDV), a non-enveloped, single-stranded, positive-sense RNA virus. The purpose of our investigation is to identify chemicals that interfere with the replication of FMDV. As part of this effort we have identified a polyoxometalate inhibitor (polyoxometalate I). We have cloned, expressed and purified FMDV RdRp. We use steady-state kinetic experiments and polymerization assays to characterize the inhibitory activity of the polyoxometalate I, determining the precise inhibitory potential and the mechanism of inhibition. Preliminary results show that polyoxometalate I inhibits the FMDV RdRp surprisingly efficiently with an IC50 of 0.5uM. Current experiments are focusing on a detailed kinetic characterization of the mechanism of action for this inhibitor. This research may provide insights that lead to new treatment options to prevent the further spread of FMD to unaffected animals.USD
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A Spontaneous Fatp4/Scl27a4 Splice Site Mutation in a New Murine Model for Congenital Ichthyosis
Congenital ichthyoses are life-threatening conditions in humans. We describe here the identification and molecular characterization of a novel recessive mutation in mice that results in newborn lethality with severe congenital lamellar ichthyosis. Mutant newborns have a taut, shiny, non-expandable epidermis that resembles cornified manifestations of autosomal-recessive congenital ichthyosis in humans. The skin is stretched so tightly that the newborn mice are immobilized. The genetic defect was mapped to a region near the proximal end of chromosome 2 by SNP analysis, suggesting Fatp4/Slc27a4 as a candidate gene. FATP4 mutations in humans cause ichthyosis prematurity syndrome (IPS), and mutations of Fatp4 in mice have previously been found to cause a phenotype that resembles human congenital ichthyoses. Characterization of the Fatp4 cDNA revealed a fusion of exon 8 to exon 10, with deletion of exon 9. Genomic sequencing identified an A to T mutation in the splice donor sequence at the 3′-end of exon 9. Loss of exon 9 results in a frame shift mutation upstream from the conserved very long-chain acyl-CoA synthase (VLACS) domain. Histological studies revealed that the mutant mice have defects in keratinocyte differentiation, along with hyperproliferation of the stratum basale of the epidermis, a hyperkeratotic stratum corneum, and reduced numbers of secondary hair follicles. Since Fatp4 protein is present primarily at the stratum granulosum and the stratum spinosum, the hyperproliferation and the alterations in hair follicle induction suggest that very long chain fatty acids, in addition to being required for normal cornification, may influence signals from the stratum corneum to the basal cells that help to orchestrate normal skin differentiation
Utilization of Wellness Practices For Burnout and Stress During COVID-19 Among an Interdisciplinary Cohort of Emergency Healthcare Workers
Introduction: The Coronavirus Disease (COVID-19) introduced additional stress to the baseline occupational stressors of emergency care workers. The objectives of this study were to evaluate perceived stress and burnout and the utilization and perceived benefit of wellness practices among emergency healthcare workers (EHCWs), including: emergency physicians, advanced practice providers (APPs), nurses, and departmental administrative staff during the COVID-19 pandemic.
Methods: A cross-sectional 28-item electronic survey of EHCWs at three hospitals in a major United States city was used to measure participants’ utilization and perceived benefit of wellness practices, burnout (2-item measure), overall stress (perceived stress scale), and stress related to COVID-19.
Results: The sample consisted of 260 respondents (response rate 44.6%, 583 eligible). Over one-half (56.5%) reported burnout from their job and a majority (58.5%) reported moderate to high stress. Wellness activities including regular exercise and engaging in hobbies were associated with lower reports of burnout. Higher stress levels were reported by participants who had tested positive for COVID-19. Nurses reported the highest rates of burnout overall (80.6%). Females reported higher rates of burnout than males across the cohort (64.5 vs 41.9%, p = 0.001), and female APPs reported significantly higher burnout than did male APPs (69.2 vs 38.5%, p = 0.048). Participants reported donated personal protective equipment (PPE) and meals on shift were extremely helpful.
Conclusion: The COVID-19 pandemic was a significant contributor to the stress of EHCWs. Regular engagement in wellness activities was associated with lower rates of burnout. The benefit of engagement in wellness practices, both individual practices and organizational interventions are paramount to mitigate stress and burnout in EHCWs
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Ending preventable maternal mortality: phase II of a multi-step process to develop a monitoring framework, 2016–2030
Background
In February 2015, the World Health Organization (WHO) released “Strategies toward ending preventable maternal mortality (EPMM)” (EPMM Strategies), a direction-setting report outlining global targets and strategies for reducing maternal mortality in the Sustainable Development Goal (SDG) period. In May 2015, the EPMM Working Group outlined a plan to develop a comprehensive monitoring framework to track progress toward the achievement of these targets and priorities. This monitoring framework was developed in two phases. Phase I, which focused on identifying indicators related to the proximal causes of maternal mortality, was completed in October 2015. This paper describes the process and results of Phase II, which was completed in November 2016 and aimed to build consensus on a set of indicators that capture information on the social, political, and economic determinants of maternal health and mortality.
Findings
A total of 150 experts from more than 78 organizations worldwide participated in this second phase of the process to develop a comprehensive monitoring framework for EPMM. The experts considered a total of 118 indicators grouped into the 11 key themes outlined in the EPMM report, ultimately reaching consensus on a set of 25 indicators, five equity stratifiers, and one transparency stratifier.
Conclusion
The indicators identified in Phase II will be used along with the Phase I indicators to monitor progress towards ending preventable maternal deaths. Together, they provide a means for monitoring not only the essential clinical interventions needed to save lives but also the equally important political, social, economic and health system determinants of maternal health and survival. These distal factors are essential to creating the enabling environment and high-performing health systems needed to ensure high-quality clinical care at the point of service for every woman, her fetus and newborn. They complement and support other monitoring efforts, in particular the “Survive, Thrive, and Transform” agenda laid out by the Global Strategy for Women’s, Children’s and Adolescents’ Health (2016-2030) and the SDG3 global target on maternal mortality
Biowaiver Monographs for Immediate‐Release Solid Oral Dosage Forms: Codeine Phosphate
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106898/1/jps23977.pd
A forward genetic screen with a thalamocortical axon reporter mouse yields novel neurodevelopment mutants and a distinct emx2 mutant phenotype
<p>Abstract</p> <p>Background</p> <p>The dorsal thalamus acts as a gateway and modulator for information going to and from the cerebral cortex. This activity requires the formation of reciprocal topographic axon connections between thalamus and cortex. The axons grow along a complex multistep pathway, making sharp turns, crossing expression boundaries, and encountering intermediate targets. However, the cellular and molecular components mediating these steps remain poorly understood.</p> <p>Results</p> <p>To further elucidate the development of the thalamocortical system, we first created a thalamocortical axon reporter line to use as a genetic tool for sensitive analysis of mutant mouse phenotypes. The TCA-<it>tau-lacZ </it>reporter mouse shows specific, robust, and reproducible labeling of thalamocortical axons (TCAs), but not the overlapping corticothalamic axons, during development. Moreover, it readily reveals TCA pathfinding abnormalities in known cortical mutants such as <it>reeler</it>. Next, we performed an unbiased screen for genes involved in thalamocortical development using random mutagenesis with the TCA reporter. Six independent mutant lines show aberrant TCA phenotypes at different steps of the pathway. These include ventral misrouting, overfasciculation, stalling at the corticostriatal boundary, and invasion of ectopic cortical cell clusters. An outcross breeding strategy coupled with a genomic panel of single nucleotide polymorphisms facilitated genetic mapping with small numbers of mutant mice. We mapped a ventral misrouting mutant to the <it>Emx2 </it>gene, and discovered that some TCAs extend to the olfactory bulbs in this mutant. Mapping data suggest that other lines carry mutations in genes not previously known for roles in thalamocortical development.</p> <p>Conclusions</p> <p>These data demonstrate the feasibility of a forward genetic approach to understanding mammalian brain morphogenesis and wiring. A robust axonal reporter enabled sensitive analysis of a specific axon tract inside the mouse brain, identifying mutant phenotypes at multiple steps of the pathway, and revealing a new aspect of the <it>Emx2 </it>mutant. The phenotypes highlight vulnerable choice points and latent tendencies of TCAs, and will lead to a refined understanding of the elements and interactions required to form the thalamocortical system.</p> <p>See Commentary: <url>http://www.biomedcentral.com/1741-7007/9/1</url></p
De novo CNVs in bipolar affective disorder and schizophrenia
An increased rate of de novo copy number variants (CNVs) has been found in schizophrenia (SZ), autism and developmental delay. An increased rate has also been reported in bipolar affective disorder (BD). Here, in a larger BD sample, we aimed to replicate these findings and compare de novo CNVs between SZ and BD. We used Illumina microarrays to genotype 368 BD probands, 76 SZ probands and all their parents. Copy number variants were called by PennCNV and filtered for frequency (10 kb). Putative de novo CNVs were validated with the z-score algorithm, manual inspection of log R ratios (LRR) and qPCR probes. We found 15 de novo CNVs in BD (4.1% rate) and 6 in SZ (7.9% rate). Combining results with previous studies and using a cut-off of >100 kb, the rate of de novo CNVs in BD was intermediate between controls and SZ: 1.5% in controls, 2.2% in BD and 4.3% in SZ. Only the differences between SZ and BD and SZ and controls were significant. The median size of de novo CNVs in BD (448 kb) was also intermediate between SZ (613 kb) and controls (338 kb), but only the comparison between SZ and controls was significant. Only one de novo CNV in BD was in a confirmed SZ locus (16p11.2). Sporadic or early onset cases were not more likely to have de novo CNVs. We conclude that de novo CNVs play a smaller role in BD compared with SZ. Patients with a positive family history can also harbour de novo mutations
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