302 research outputs found
The zebrafish xenograft platform-A novel tool for modeling KSHV-associated diseases
Kaposi\u27s sarcoma associated-herpesvirus (KSHV, also known as human herpesvirus-8) is a gammaherpesvirus that establishes life-long infection in human B lymphocytes. KSHV infection is typically asymptomatic, but immunosuppression can predispose KSHV-infected individuals to primary effusion lymphoma (PEL); a malignancy driven by aberrant proliferation of latently infected B lymphocytes, and supported by pro-inflammatory cytokines and angiogenic factors produced by cells that succumb to lytic viral replication. Here, we report the development of the firs
The zebrafish reveals dependence of the mast cell lineage on Notch signaling in vivo
We used the opportunities afforded by the zebrafish to determine upstream pathways regulating mast cell development in vivo and identify their cellular origin. Colocalization studies demonstrated zebrafish notch receptor expression in cells expressing carboxypeptidase A5 (cpa5), a zebrafish mast cell-specific marker. Inhibition of the Notch pathway resulted in decreased cpa5 expression in mindbomb mutants and wild-type embryos treated with the γ-secretase inhibitor, Compound E.Aseries of morpholino knockdown studies specifically identified notch1b and gata2 as the critical factors regulating mast cell fate. Moreover, hsp70::GAL4;UAS::nicd1a transgenic embryos overexpressing an activated form of notch1, nicd1a, displayed increased cpa5, gata2, and pu.1 expression. This increase in cpa5 expression could be reversed and reduced below baseline levels in a dose-dependent manner usingCompound E. Finally, evidence that cpa5 expression colocalizes with lmo2 in the absence of hematopoietic stem cells revealed that definitive mast cells initially delineate from erythromyeloid progenitors. These studies identify a master role for Notch signaling in vertebrate mast cell development and establish developmental origins of this lineage. Moreover, these findings postulate targeting the Notch pathway as a therapeutic strategy in mast cell diseases. © 2012 by The American Society of Hematology
Advanced Metering Plan for Monitoring Energy and Potable Water Use in PNNL EMS4 Buildings
This updated Advanced Metering Plan for monitoring whole building energy use in Pacific Northwest National Laboratory (PNNL) EMS4 buildings on the PNNL campus has been prepared in accordance with the requirements of the Energy Policy Act of 2005 (EPAct 2005), Section 103, U.S. Department of Energy (DOE) Order 430.2B, and Metering Best Practices, A Guide to Achieving Utility Resource Efficiency, Federal Energy Management Program, October 2007 (Sullivan et al. 2007). The initial PNNL plan was developed in July 2007 (Olson 2007), updated in September 2008 (Olson et al. 2008), updated in September 2009 (Olson et al. 2009), and updated again in August 2010 (Olson et al. 2010)
Glycine and Folate Ameliorate Models of Congenital Sideroblastic Anemia
Sideroblastic anemias are acquired or inherited anemias that result in a decreased ability to
synthesize hemoglobin in red blood cells and result in the presence of iron deposits in the
mitochondria of red blood cell precursors. A common subtype of congenital sideroblastic
anemia is due to autosomal recessive mutations in the SLC25A38 gene. The current treatment
for SLC25A38 congenital sideroblastic anemia is chronic blood transfusion coupled
with iron chelation. The function of SLC25A38 is not known. Here we report that the
SLC25A38 protein, and its yeast homolog Hem25, are mitochondrial glycine transporters
required for the initiation of heme synthesis. To do so, we took advantage of the fact that
mitochondrial glycine has several roles beyond the synthesis of heme, including the synthesis
of folate derivatives through the glycine cleavage system. The data were consistent with
Hem25 not being the sole mitochondrial glycine importer, and we identify a second SLC25
family member Ymc1, as a potential secondary mitochondrial glycine importer. Based on
these findings, we observed that high levels of exogenous glycine, or 5-aminolevulinic acid
(5-Ala) a metabolite downstream of Hem25 in heme biosynthetic pathway, were able to
restore heme levels to normal in yeast cells lacking Hem25 function. While neither glycine
nor 5-Ala could ameliorate SLC25A38 congenital sideroblastic anemia in a zebrafish
model, we determined that the addition of folate with glycine was able to restore hemoglobin
levels. This difference is likely due to the fact that yeast can synthesize folate, whereas in
zebrafish folate is an essential vitamin that must be obtained exogenously. Given the tolerability
of glycine and folate in humans, this study points to a potential novel treatment for
SLC25A38 congenital sideroblastic anemia.Genome Canada as large-scale applied research project with funding contributions from the Dalhousie Medical Research Foundation, the Nova Scotia Research Innovation Trust, and the Nova Scotia Department of Health and Wellnes
The Shearing HI Spiral Pattern of NGC 1365
The Tremaine-Weinberg equations are solved for a pattern speed that is
allowed to vary with radius. The solution method transforms an integral
equation for the pattern speed to a least squares problem with well established
procedures for statistical analysis. The method applied to the HI spiral
pattern of the barred, grand-design galaxy NGC 1365 produced convincing
evidence for a radial dependence in the pattern speed. The pattern speed
behaves approximately as 1/r, and is very similar to the material speed. There
are no clear indications of corotation or Lindblad resonances. Tests show that
the results are not selection biased, and that the method is not measuring the
material speed. Other methods of solving the Tremaine-Weinberg equations for
shearing patterns were found to produce results in agreement with those
obtained using the current method. Previous estimates that relied on the
assumptions of the density-wave interpretation of spiral structure are
inconsistent with the results obtained using the current method. The results
are consistent with spiral structure theories that allow for shearing patterns,
and contradict fundamental assumptions in the density-wave interpretation that
are often used for finding spiral arm pattern speeds. The spiral pattern is
winding on a characteristic timescale of ~ 500 Myrs.Comment: Accepted for publication in The Astrophysical Journa
Humanized zebrafish enhance human hematopoietic stem cell survival and promote acute myeloid leukemia clonal diversity
Xenograft models are invaluable tools in establishing the current paradigms of hematopoiesis and leukemogenesis. The zebrafish has emerged as a robust alternative xenograft model but, like mice, lack specific cytokines that mimic the microenvironment found in human patients. To address this critical gap, we generated the first humanized zebrafish that express human hematopoietic-specific cytokines (GM-CSF, SCF, and SDF1α). Termed GSS fish, these zebrafish promote survival, self-renewal and multilineage differentiation of human hematopoietic stem and progenitor cells and result in enhanced proliferation and hematopoietic niche-specific homing of primary human leukemia cells. Using error-corrected RNA sequencing, we determined that patient-derived leukemias transplanted into GSS zebrafish exhibit broader clonal representation compared to transplants into control hosts. GSS zebrafish incorporating error-corrected RNA sequencing establish a new standard for zebrafish xenotransplantation that more accurately recapitulates the human context, providing a more representative cost-effective preclinical model system for evaluating personalized response-based treatment in leukemia and therapies to expand human hematopoietic stem and progenitor cells in the transplant setting
Association of longitudinal changes in cerebrospinal fluid total tau and phosphorylated tau 181 and brain atrophy with disease progression in patients with Alzheimer disease
Importance: The amyloid/tau/neurodegeneration (A/T/N) framework uses cerebrospinal fluid (CSF) levels of total tau (tTau) as a marker of neurodegeneration and CSF levels of phosphorylated tau 181 (pTau181) as a marker of tau tangles. However, it is unclear whether CSF levels of tTau and pTau181 have similar or different trajectories over the course of Alzheimer disease.
Objectives: To examine the rates of change in CSF levels of tTau and pTau181 across the Alzheimer disease course and how the rates of change are associated with brain atrophy as measured by magnetic resonance imaging.
Design, Setting, and Participants: This cohort study was set in tertiary research clinics. Each participant was a member of a pedigree with a known mutation for dominantly inherited Alzheimer disease. Participants were divided into 3 groups on the basis of the presence of a mutation and their Clinical Dementia Rating score. Data analysis was performed in June 2019.
Main Outcomes and Measures: Rates of change of CSF tTau and pTau181 levels and their association with the rate of change of brain volume.
Results: Data from 465 participants (283 mutation carriers and 182 noncarriers) were analyzed. The mean (SD) age of the cohort was 37.8 (11.3) years, and 262 (56.3%) were women. The mean (SD) follow-up duration was 2.7 (1.5) years. Two or more longitudinal CSF and magnetic resonance imaging assessments were available for 160 and 247 participants, respectively. Sixty-five percent of mutation carriers (183) did not have symptoms at baseline (Clinical Dementia Rating score, 0). For mutation carriers, the annual rates of change for CSF tTau and pTau181 became significantly different from 0 approximately 10 years before the estimated year of onset (mean [SE] rates of change, 5.5 [2.8] for tTau [P = .05] and 0.7 [0.3] for pTau 181 [P = .04]) and 15 years before onset (mean [SE] rates of change, 5.4 [3.9] for tTau [P = .17] and 1.1 [0.5] for pTau181 [P = .03]), respectively. The rate of change of pTau181 was positive and increased at the early stages of the disease, showing a positive rate of change starting at 15 estimated years before onset until 5 estimated years before onset (mean [SE], 0.4 [0.3]), followed by a positive but decreasing rate of change at year 0 (mean [SE], 0.1 [0.3]) and then negative rates of change at 5 years (mean [SE], -0.3 [0.4]) and 10 years (mean [SE], -0.6 [0.6]) after symptom onset. In individuals without symptoms (Clinical Dementia Rating score, 0), the rates of change of CSF tTau and pTau181 were negatively associated with brain atrophy (high rates of change in CSF measures were associated with low rates of change in brain volume in asymptomatic stages). After symptom onset (Clinical Dementia Rating score, \u3e0), an increased rate of brain atrophy was not associated with rates of change of levels of both CSF tTau and pTau181.
Conclusions and Relevance: These findings suggest that CSF tTau and pTau181 may have different associations with brain atrophy across the disease time course. These results have implications for understanding the dynamics of disease pathobiology and interpreting neuronal injury biomarker concentrations in response to Alzheimer disease progression and disease-modifying therapies
Effectiveness guidance document (EGD) for acupuncture research - a consensus document for conducting trials
Abstract
Background
There is a need for more Comparative Effectiveness Research (CER) to strengthen the evidence base for clinical and policy decision-making. Effectiveness Guidance Documents (EGD) are targeted to clinical researchers. The aim of this EGD is to provide specific recommendations for the design of prospective acupuncture studies to support optimal use of resources for generating evidence that will inform stakeholder decision-making.
Methods
Document development based on multiple systematic consensus procedures (written Delphi rounds, interactive consensus workshop, international expert review). To balance aspects of internal and external validity, multiple stakeholders including patients, clinicians and payers were involved.
Results
Recommendations focused mainly on randomized studies and were developed for the following areas: overall research strategy, treatment protocol, expertise and setting, outcomes, study design and statistical analyses, economic evaluation, and publication.
Conclusion
The present EGD, based on an international consensus developed with multiple stakeholder involvement, provides the first systematic methodological guidance for future CER on acupuncture.http://deepblue.lib.umich.edu/bitstream/2027.42/112870/1/12906_2012_Article_1127.pd
Highly fluorinated naphthalenes and bifurcated C–H⋯F–C hydrogen bonding
The synthesis and crystal structures of 1,2,4,5,6,8-hexafluoronaphthalene and 1,2,4,6,8-pentafluoronaphthalene are reported. Intermolecular interactions are dominated by offset stacking and by C–H⋯F–C hydrogen bonds. For hexafluoronaphthalene, molecules are linked in layers with (4,4) network topology via R12(6) C–H⋯(F–C)2 supramolecular synthons that are rationalised by consideration of the calculated electrostatic potential of the molecule. Such an arrangement is prevented by the additional hydrogen atom in pentafluoronaphthalene and molecules instead form tapes via an R12(8) (C–H⋯F)2 synthon. The geometric characteristics of C–H⋯(F–C)2 bifurcated hydrogen bonds have been analysed for crystal structures in the Cambridge Structural Database (6416 crystal structures; 9534 C–H⋯(F–C)2 bifurcated hydrogen bonds). A geometric analysis of these hydrogen bonds has enabled the extent of asymmetry of these hydrogen bonds to be assessed and indicates a preference for symmetrically bifurcated interactions
Development and validation of an improved algorithm for overlaying flexible molecules
A program for overlaying multiple flexible molecules has been developed. Candidate overlays are generated by a novel fingerprint algorithm, scored on three objective functions (union volume, hydrogen-bond match, and hydrophobic match), and ranked by constrained Pareto ranking. A diverse subset of the best ranked solutions is chosen using an overlay-dissimilarity metric. If necessary, the solutions can be optimised. A multi-objective genetic algorithm can be used to find additional overlays with a given mapping of chemical features but different ligand conformations. The fingerprint algorithm may also be used to produce constrained overlays, in which user-specified chemical groups are forced to be superimposed. The program has been tested on several sets of ligands, for each of which the true overlay is known from protein–ligand crystal structures. Both objective and subjective success criteria indicate that good results are obtained on the majority of these sets
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