860 research outputs found
let-7 microRNAs regulate microglial function and suppress glioma growth through Toll-like receptor 7
Microglia express Toll-like receptors (TLRs) that sense pathogen- and host-derived factors, including single-stranded RNA. In the brain, let-7 microRNA (miRNA) family members are abundantly expressed, and some have recently been shown to serve as TLR7 ligands. We investigated whether let-7 miRNA family members differentially control microglia biology in health and disease. We found that a subset of let-7 miRNA family members function as signaling molecules to induce microglial release of inflammatory cytokines, modulate antigen presentation, and attenuate cell migration in a TLR7-dependent manner. The capability of the let-7 miRNAs to control microglial function is sequence specific, mapping to a let-7 UUGU motif. In human and murine glioblastoma/glioma, let-7 miRNAs are differentially expressed and reduce murine GL261 glioma growth in the same sequence-specific fashion through microglial TLR7. Taken together, these data establish let-7 miRNAs as key TLR7 signaling activators that serve to regulate the diverse functions of microglia in health and glioma
Reproducibility of cognitive endpoints in clinical trials: Lessons from neurofibromatosis type 1
OBJECTIVE: Rapid developments in understanding the molecular mechanisms underlying cognitive deficits in neurodevelopmental disorders have increased expectations for targeted, mechanism-based treatments. However, translation from preclinical models to human clinical trials has proven challenging. Poor reproducibility of cognitive endpoints may provide one explanation for this finding. We examined the suitability of cognitive outcomes for clinical trials in children with neurofibromatosis type 1 (NF1) by examining test-retest reliability of the measures and the application of data reduction techniques to improve reproducibility.
METHODS: Data were analyzed from the STARS clinical trial (n = 146), a multi-center double-blind placebo-controlled phase II trial of lovastatin, conducted by the NF Clinical Trials Consortium. Intra-class correlation coefficients were generated between pre- and post-performances (16-week interval) on neuropsychological endpoints in the placebo group to determine test-retest reliabilities. Confirmatory factor analysis was used to reduce data into cognitive domains and account for measurement error.
RESULTS: Test-retest reliabilities were highly variable, with most endpoints demonstrating unacceptably low reproducibility. Data reduction confirmed four distinct neuropsychological domains: executive functioning/attention, visuospatial ability, memory, and behavior. Test-retest reliabilities of latent factors improved to acceptable levels for clinical trials. Applicability and utility of our model was demonstrated by homogeneous effect sizes in the reanalyzed efficacy data.
INTERPRETATION: These data demonstrate that single observed endpoints are not appropriate to determine efficacy, partly accounting for the poor test-retest reliability of cognitive outcomes in clinical trials in neurodevelopmental disorders. Recommendations to improve reproducibility are outlined to guide future trial design
Tumor suppressor Tsc1 is a new Hsp90 co‐chaperone that facilitates folding of kinase and non‐kinase clients
The taxonomy of brain cancer stem cells: What\u27s in a name?
With the increasing recognition that stem cells play vital roles in the formation, maintenance, and potential targeted treatment of brain tumors, there has been an exponential increase in basic laboratory and translational research on these cell types. However, there are several different classes of stem cells germane to brain cancer, each with distinct capabilities and functions. In this perspective, we discuss the types of stem cells relevant to brain tumor pathogenesis, and suggest a nomenclature for future preclinical and clinical investigation
Children with 5′-end NF1 gene mutations are more likely to have glioma
Objective:To ascertain the relationship between the germline NF1 gene mutation and glioma development in patients with neurofibromatosis type 1 (NF1).Methods:The relationship between the type and location of the germline NF1 mutation and the presence of a glioma was analyzed in 37 participants with NF1 from one institution (Washington University School of Medicine [WUSM]) with a clinical diagnosis of NF1. Odds ratios (ORs) were calculated using both unadjusted and weighted analyses of this data set in combination with 4 previously published data sets.Results:While no statistical significance was observed between the location and type of the NF1 mutation and glioma in the WUSM cohort, power calculations revealed that a sample size of 307 participants would be required to determine the predictive value of the position or type of the NF1 gene mutation. Combining our data set with 4 previously published data sets (n = 310), children with glioma were found to be more likely to harbor 5′-end gene mutations (OR = 2; p = 0.006). Moreover, while not clinically predictive due to insufficient sensitivity and specificity, this association with glioma was stronger for participants with 5′-end truncating (OR = 2.32; p = 0.005) or 5′-end nonsense (OR = 3.93; p = 0.005) mutations relative to those without glioma.Conclusions:Individuals with NF1 and glioma are more likely to harbor nonsense mutations in the 5′ end of the NF1 gene, suggesting that the NF1 mutation may be one predictive factor for glioma in this at-risk population.</jats:sec
Unstructured Randomness, Small Gaps and Localization
We study the Hamiltonian associated with the quantum adiabatic algorithm with
a random cost function. Because the cost function lacks structure we can prove
results about the ground state. We find the ground state energy as the number
of bits goes to infinity, show that the minimum gap goes to zero exponentially
quickly, and we see a localization transition. We prove that there are no
levels approaching the ground state near the end of the evolution. We do not
know which features of this model are shared by a quantum adiabatic algorithm
applied to random instances of satisfiability since despite being random they
do have bit structure
German Churches in Times of Demographic Change and Declining Affiliation: A Projection to 2060
The problem of declining membership in Germany’s churches has been apparent for almost half a century. However, few scientific studies have investigated the respective influences of demographic and church-specific phenomena, as well as the potential impact if present trends continue. To answer these questions, we use a cohort component model and project the membership of each German Catholic diocese and Protestant regional church until 2060. Thus, for the first time we present a projection of church members for each of the 27 Catholic (arch-) dioceses and the 20 Protestant regional churches, as well as for the entire Evangelical Church and the Roman Catholic Church in Germany. We collected data from dioceses, Protestant regional churches and the Federal Statistical Office. Under the assumptions made, the results suggest a continued decline in membership and that by 2060 the number of church members would be half the number of 2017. Protestant Church membership would have shrunk slightly more than Catholic Church membership. We can conclude that church-specific factors (baptisms, leaving, and joining the church) would have a stronger influence on declining numbers than demographic factors. Moreover, demographic change would have a greater impact on registered church membership than on the total population. The proportion of Christians in the population would sharply decrease. Although in 2017 54.4 percent of the population belonged to one of the two major churches, according to the projection model, only 31.1 percent would be church members in 2060. As our results are not predictions but projections using trend analysis, we show how changed conditions would affect the projected development in five scenarios
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