3,797 research outputs found

    Effects of APOE4 allelic dosage on lipidomic signatures in the entorhinal cortex of aged mice

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    Apolipoprotein E ε4 (APOE4) is the primary genetic risk factor for the late-onset form of Alzheimer's disease (AD). Although the reason for this association is not completely understood, researchers have uncovered numerous effects of APOE4 expression on AD-relevant brain processes, including amyloid beta (Aβ) accumulation, lipid metabolism, endosomal-lysosomal trafficking, and bioenergetics. In this study, we aimed to determine the effect of APOE4 allelic dosage on regional brain lipid composition in aged mice, as well as in cultured neurons. We performed a targeted lipidomic analysis on an AD-vulnerable brain region (entorhinal cortex; EC) and an AD-resistant brain region (primary visual cortex; PVC) from 14-15 month-old APOE3/3, APOE3/4, and APOE4/4 targeted replacement mice, as well as on neurons cultured with conditioned media from APOE3/3 or APOE4/4 astrocytes. Our results reveal that the EC possesses increased susceptibility to APOE4-associated lipid alterations compared to the PVC. In the EC, APOE4 expression showed a dominant effect in decreasing diacylglycerol (DAG) levels, and a semi-dominant, additive effect in the upregulation of multiple ceramide, glycosylated sphingolipid, and bis(monoacylglycerol)phosphate (BMP) species, lipids known to accumulate as a result of endosomal-lysosomal dysfunction. Neurons treated with conditioned media from APOE4/4 vs. APOE3/3 astrocytes showed similar alterations of DAG and BMP species to those observed in the mouse EC. Our results suggest that APOE4 expression differentially modulates regional neuronal lipid signatures, which may underlie the increased susceptibility of EC-localized neurons to AD pathology

    Spectra of supernovae in the nebular phase

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    When supernovae enter the nebular phase after a few months, they reveal spectral fingerprints of their deep interiors, glowing by radioactivity produced in the explosion. We are given a unique opportunity to see what an exploded star looks like inside. The line profiles and luminosities encode information about physical conditions, explosive and hydrostatic nucleosynthesis, and ejecta morphology, which link to the progenitor properties and the explosion mechanism. Here, the fundamental properties of spectral formation of supernovae in the nebular phase are reviewed. The formalism between ejecta morphology and line profile shapes is derived, including effects of scattering and absorption. Line luminosity expressions are derived in various physical limits, with examples of applications from the literature. The physical processes at work in the supernova ejecta, including gamma-ray deposition, non-thermal electron degradation, ionization and excitation, and radiative transfer are described and linked to the computation and application of advanced spectral models. Some of the results derived so far from nebular-phase supernova analysis are discussed.Comment: Book chapter for 'Handbook of Supernovae,' edited by Alsabti and Murdin, Springer. 51 pages, 14 figure

    The neck-region polymorphism of DC-SIGNR in peri-centenarian from Han Chinese Population

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    <p>Abstract</p> <p>Background</p> <p>DC-SIGNR (also called CD209L) has been extensively studied on its role in host genetic predisposition to viral infection. In particular, variable number tandem repeat (VNTR) of the neck-region of DC-SIGNR is highly polymorphic and the polymorphism has been investigated for genetic predisposition to various infectious diseases, though conflicting results had been reported. As infection is a major cause of human death and a mechanism of natural selection, we hypothesized that VNTR polymorphism of DC-SIGNR might have an effect on human life span.</p> <p>Methods</p> <p>Here we collected 361 peri-centenarian individuals (age ≥94 for female and age ≥90 for male) and 342 geographically matched controls (age 22-53, mean 35.0 ± 12.0) from Han Chinese. The VNTR polymorphism of the neck region was determined by PCR and genotype was called by separating the PCR products in agarose gel.</p> <p>Results</p> <p>A total of 11 genotypes and 5 alleles were found in our population. The genotype distribution, allele frequencies and homozygote proportion did not show a significant difference between peri-centenarian and control group. As gender differences in lifespan are ubiquitously observed throughout the animal kingdom, we then stratified the samples by gender. There was more 6/7 genotypes in female peri-centenarian group than that in female control group, at a marginal level of significance (5.56 vs. 1.28%, p = 0.041). The difference was not significant after correction by Bonferroni method. It suggests a possible differential effect of DC-SIGNR VNTR genotypes between sexes. Further studies are warranted to confirm our preliminary findings and investigate the mechanisms of the underlying functions.</p> <p>Conclusions</p> <p>Our study indicated that there was absence of association between the neck region polymorphism of DC-SIGNR and longevity in Han Chinese population. But the question of whether the DC-SIGNR could affect longevity in a gender-specific pattern remains open.</p

    Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

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    The decay channel ψπ+πJ/ψ(J/ψγppˉ)\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) is studied using a sample of 1.06×1081.06\times 10^8 ψ\psi^\prime events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the ppˉp\bar{p} invariant mass spectrum. The enhancement can be fit with an SS-wave Breit-Wigner resonance function with a resulting peak mass of M=186113+6(stat)26+7(syst)MeV/c2M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2 and a narrow width that is Γ<38MeV/c2\Gamma<38 {\rm MeV/}c^2 at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

    Interaction between maternal caffeine intake during pregnancy and CYP1A2 C164A polymorphism affects infant birth size in the Hokkaido study

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    BACKGROUND: Caffeine, 1,3,7-trimethylxanthine, is widely consumed by women of reproductive age. Although caffeine has been proposed to inhibit fetal growth, previous studies on the effects of caffeine on infant birth size have yielded inconsistent findings. This inconsistency may result from failure to account for individual differences in caffeine metabolism related to polymorphisms in the gene for CYP1A2, the major caffeine-metabolizing enzyme. METHODS: Five hundred fourteen Japanese women participated in a prospective cohort study in Sapporo, Japan, from 2002 to 2005, and 476 mother-child pairs were included for final analysis. RESULTS: Caffeine intake was not significantly associated with mean infant birth size. When caffeine intake and CYP1A2 C164A genotype were considered together, women with the AA genotype and caffeine intake of >= 300 mg per day had a mean reduction in infant birth head circumference of 0.8 cm relative to the reference group after adjusting for confounding factors. In a subgroup analysis, only nonsmokers with the AA genotype and caffeine intake of >= 300 mg per day had infants with decreased birth weight (mean reduction, 277 g) and birth head circumference (mean reduction, 1.0 cm). CONCLUSION: Nonsmokers who rapidly metabolize caffeine may be at increased risk for having infants with decreased birth size when consuming >= 300 mg of caffeine per day.This is the author's accepted version of their manuscript of the following article: Sasaki, et al. Pediatric Research (2017) 82, 19–28. The final publication is available at: http://dx.doi.org/10.1038/pr.2017.7

    Markers for early detection of cancer: Statistical guidelines for nested case-control studies

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    BACKGROUND: Recently many long-term prospective studies have involved serial collection and storage of blood or tissue specimens. This has spurred nested case-control studies that involve testing some specimens for various markers that might predict cancer. Until now there has been little guidance in statistical design and analysis of these studies. METHODS: To develop statistical guidelines, we considered the purpose, the types of biases, and the opportunities for extracting additional information. RESULTS: The following guidelines: (1) For the clearest interpretation, statistics should be based on false and true positive rates – not odds ratios or relative risks (2) To avoid overdiagnosis bias, cases should be diagnosed as a result of symptoms rather than on screening. (3) To minimize selection bias, the spectrum of control conditions should be the same in study and target screening populations. (4) To extract additional information, criteria for a positive test should be based on combinations of individual markers and changes in marker levels over time. (5) To avoid overfitting, the criteria for a positive marker combination developed in a training sample should be evaluated in a random test sample from the same study and, if possible, a validation sample from another study. (6) To identify biomarkers with true and false positive rates similar to mammography, the training, test, and validation samples should each include at least 110 randomly selected subjects without cancer and 70 subjects with cancer. CONCLUSION: These guidelines ensure good practice in the design and analysis of nested case-control studies of early detection biomarkers

    IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

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    Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Opportunities, challenges and systems requirements for developing post-abortion family planning services: Perceptions of service stakeholders in China

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    Post-abortion family planning (PAFP) has been proposed as a key strategy to decrease unintended pregnancy and repeat induced abortions. However, the accessibility and quality of PAFP services remain a challenge in many countries including China where more than 10 million unintended pregnancies occur each year. Most of these unwanted pregnancies end in repeated induced abortions. This paper aims to explore service providers’ perceptions of the current situation regarding family planning and abortion service needs, provision, utilization, and the feasibility and acceptability of high quality PAFP in the future. Qualitative methods, including in-depth interviews and focus group discussions, were used with family planning policy makers, health managers, and service providers. Three provinces—Zhejiang, Hubei and Yunnan—were purposively selected, representing high, medium and relatively undeveloped areas of China. A total of fifty-three in-depth interviews and ten focus-group discussions were conducted and analysed thematically. Increased numbers of abortions among young, unmarried women were perceived as a major reason for high numbers of abortions. Participants attributed this to increasing socio-cultural acceptability of premarital sex, and simultaneously, lack of understanding or awareness of contraception among young people. The majority of service stakeholders acknowledged that free family planning services were neither targeted at, nor accessible to unmarried people. The extent of PAFP provision is variable and limited. However, service providers expressed willingness and enthusiasm towards providing PAFP services in the future. Three main considerations were expressed regarding the feasibility of developing and implementing PAFP services: policy support, human resources, and financial resources. The study indicated that key service stakeholders show demand for and perceive considerable opportunities to develop PAFP in China. However, changes are needed to enable the systematic development of high quality PAFP, including actively targeting young and unmarried people in service provision, obtaining policy support and increasing the investment of human and financial resources

    Neuronal pentraxin II is highly upregulated in Parkinson’s disease and a novel component of Lewy bodies

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    Neuronal pentraxin II (NPTX2) is the most highly upregulated gene in the Parkinsonian substantia nigra based on our whole genome expression profiling results. We show here that it is a novel component of Lewy bodies and Lewy neurites in sporadic Parkinson’s disease (PD). NPTX2 is also known as the neuronal activity-regulated protein (Narp), which is secreted and involved in long-term neuronal plasticity. Narp further regulates AMPA receptors which have been found to mediate highly selective non-apoptotic cell death of dopaminergic neurons. NPTX2/Narp is found in close association with alpha-synuclein aggregates in both substantia nigra and cerebral cortex in PD but unlike alpha-synuclein gene expression, which is down-regulated in the Parkinsonian nigra, NPTX2 could represent a driver of the disease process. In view of its profound (>800%) upregulation and its established role in synaptic plasticity as well as dopaminergic nerve cell death, NPTX2 is a very interesting novel player which is likely to be involved in the pathway dysregulation which underlies PD

    LIGHT Induces Distinct Signals to Clear an AAV-Expressed Persistent Antigen in the Mouse Liver and to Induce Liver Inflammation

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    Background: Infection with adeno-associated virus (AAV) vector with liver tropism leads to persistent expression of foreign antigens in the mouse liver, with no significant liver inflammation or pathology. This provides a model to investigate antigen persistence in the liver and strategies to modulate host immunity to reduce or clear the foreign antigen expressed from AAV vector in the liver. Methods/Principal Findings: We showed that expressing LIGHT with an adenovirus vector (Ad) in mice with established AAV in the liver led to clearance of the AAV. Ad-LIGHT enhanced CD8 effector T cells in the liver, correlated with liver inflammation. LTbR-Ig proteins blocked Ad-LIGHT in clearing AAV. Interestingly, in LTbR-null mice, Ad-LIGHT still cleared AAV but caused no significant liver inflammation. Conclusions/Significance: Our data suggest that LIGHT interaction with the LTbR plays a critical role in liver inflammation but is not required for LIGHT-mediated AAV clearance. These findings will shed light on developing novel immunotherapeutic
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