70 research outputs found

    MRI of Perfusion-Diffusion Mismatch in Non-Human Primate (Baboon) Stroke: A Preliminary Report

    Get PDF
    The goal of this study was to develop a clinically relevant non-human primate (baboon) stroke model and multi-parametric MRI protocols on a clinical scanner with long-term goals to better model human stroke and facilitate clinical translations of novel therapeutic strategies. Baboons were chosen because of their relatively large brain volume and that they are evolutionarily close to humans. Middle cerebral artery occlusion (MCAO) was induced using a minimally invasive endovascular approach to guide an inflatable balloon catheter into the MCA and followed by permanently or transiently inflate the balloon. Using multimodal MRI, including perfusion and diffusion imaging, the spatiotemporal dynamic evolution of the ischemic lesions in permanent and transient occlusion experiments in baboons were investigated. Perfusion-diffusion mismatch, which approximates the ischemic penumbra, was detected. In the permanent MCAO group (n = 2), the mean infarct volume was 29 ml (17% of total brain volume) whereas in the transient MCAO group (n = 2, 60 or 90 min of occlusion), the mean infarct volume was 15 ml (9% of total brain volume). Substantial perfusion-diffusion mismatch tissue (~50%) was salvaged by reperfusion compared to permanent MCAO. This baboon stroke model has the potential to become a translational platform to better design clinical studies, guide clinical diagnosis and improve treatment time windows in patients

    Amplification of simian retroviral sequences from human recipients of baboon liver transplants

    Get PDF
    Investigations into the use of baboons as organ donors for human transplant recipients, a procedure called xenotransplantation, have raised the specter of transmitting baboon viruses to humans and possibly establishing new human infectious diseases. Retrospective analysis of tissues from two human transplant recipients with end-stage hepatic disease who died 70 and 27 days after the transplantation of baboon livers revealed the presence of two simian retroviruses of baboon origin, simian foamy virus (SFV) and baboon endogenous virus (BaEV), in multiple tissue compartments. The presence of baboon mitochondrial DNA was also detected in these same tissues, suggesting that xenogeneic 'passenger leukocytes' harboring latent or active viral infections had migrated from the xenografts to distant sites within the human recipients. The persistence of SFV and BaEV in human recipients throughout the posttransplant period underscores the potential infectious risks associated with xenotransplantation

    Piolhos hematófagos podem disseminar infecção pelo Trypanosoma cruzi em babuínos

    Get PDF
    Trypanosoma cruzi (Schyzotrypanum, Chagas, 1909), and Chagas disease are endemic in captive-reared baboons at the Southwest Foundation for Biomedical Research, San Antonio, Texas. We obtained PCR amplification products from DNA extracted from sucking lice collected from the hair and skin of T. cruzi-infected baboons, with specific nested sets of primers for the protozoan kinetoplast DNA, and nuclear DNA. These products were hybridized to their complementary internal sequences. Selected sequences were cloned and sequencing established the presence of T. cruzi nuclear DNA, and minicircle kDNA. Competitive PCR with a kDNA set of primers determined the quantity of approximately 23.9 ± 18.2 T. cruzi per louse. This finding suggests that the louse may be a vector incidentally contributing to the dissemination of T. cruzi infection in the baboon colony.As infecções pelo Trypanosoma cruzi e a doença de Chagas são endêmicas em babuínos (Papio hamadryas) reproduzidos em cativeiro na Southwest Foundation for Biomedical Research, em Santo Antonio, Texas. Nós obtivemos produtos de amplificação por PCR do DNA extraído de piolhos colhidos do cabelo e da pele de babuínos chagásicos, com primers aneladores específicos para DNAs nuclear e de cinetoplasto do protozoário. Esses produtos foram hibridizados com suas respectivas seqüências internas complementares. Seqüências selecionadas foram clonadas e o sequenciamento demonstrou a presença de DNA nuclear de T. cruzi, e de minicírculo de kDNA. A PCR competitiva com primers de kDNA determinou a quantidade de aproximadamente 23.9 ± 18.2 T. cruzi por piolho. Este achado sugere que o piolho pode ser um vetor contribuindo para a disseminação de T. cruzi na colônia de babuínos

    Whole Genome Sequence Data From Captive Baboons Implicate RBFOX1 in Epileptic Seizure Risk

    Get PDF
    In this study, we investigate the genetic determinants that underlie epilepsy in a captive baboon pedigree and evaluate the potential suitability of this non-human primate model for understanding the genetic etiology of human epilepsy. Archived whole-genome sequence data were analyzed using both a candidate gene approach that targeted variants in baboon homologs of 19 genes (n = 20,881 SNPs) previously implicated in genetic generalized epilepsy (GGE) and a more agnostic approach that examined protein-altering mutations genome-wide as assessed by snpEff (n = 36,169). Measured genotype association tests for baboon cases of epileptic seizure were performed using SOLAR, as well as gene set enrichment analyses (GSEA) and protein–protein interaction (PPI) network construction of top association hits genome-wide (p \u3c 0.01; n = 441 genes). The maximum likelihood estimate of heritability for epileptic seizure in the pedigreed baboon sample is 0.76 (SE = 0.77; p = 0.07). Among candidate genes for GGE, a significant association was detected for an intronic SNP in RBFOX1 (p = 5.92 × 10–6; adjusted p = 0.016). For protein-altering variants, no genome-wide significant results were observed for epilepsy status. However, GSEA revealed significant positive enrichment for genes involved in the extracellular matrix structure (ECM; FDR = 0.0072) and collagen formation (FDR = 0.017), which was reflected in a major PPI network cluster. This preliminary study highlights the potential role of RBFOX1 in the epileptic baboon, a protein involved in transcriptomic regulation of multiple epilepsy candidate genes in humans and itself previously implicated in human epilepsy, both focal and generalized. Moreover, protein-damaging variants from across the genome exhibit a pattern of association that links collagen-containing ECM to epilepsy risk. These findings suggest a shared genetic etiology between baboon and human forms of GGE and lay the foundation for follow-up research

    Predictive models of insulin resistance derived from simple morphometric and biochemical indices related to obesity and the metabolic syndrome in baboons

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Non-human primates are valuable models for the study of insulin resistance and human obesity. In baboons, insulin sensitivity levels can be evaluated directly with the euglycemic clamp and is highly predicted by adiposity, metabolic markers of obesity and impaired glucose metabolism (i.e. percent body fat by DXA and HbA<sub>1c</sub>). However, a simple method to screen and identify obese insulin resistant baboons for inclusion in interventional studies is not available.</p> <p>Methods</p> <p>We studied a population of twenty baboons with the euglycemic clamp technique to characterize a population of obese nondiabetic, insulin resistant baboons, and used a multivariate linear regression analysis (adjusted for gender) to test different predictive models of insulin sensitivity (insulin-stimulated glucose uptake = Rd) using abdominal circumference and fasting plasma insulin. Alternatively, we tested in a separate baboon population (n = 159), a simpler model based on body weight and fasting plasma glucose to predict the whole-body insulin sensitivity (Rd/SSPI) derived from the clamp.</p> <p>Results</p> <p>In the first model, abdominal circumference explained 59% of total insulin mediated glucose uptake (Rd). A second model, which included fasting plasma insulin (log transformed) and abdominal circumference, explained 64% of Rd. Finally, the model using body weight and fasting plasma glucose explained 51% of Rd/SSPI. Interestingly, we found that percent body fat was directly correlated with the adipocyte insulin resistance index (r = 0.755, p < 0.0001).</p> <p>Conclusion</p> <p>In baboons, simple morphometric measurements of adiposity/obesity, (i.e. abdominal circumference), plus baseline markers of glucose/lipid metabolism, (i.e. fasting plasma glucose and insulin) provide a feasible method to screen and identify overweight/obese insulin resistant baboons for inclusion in interventional studies aimed to study human obesity, insulin resistance and type 2 diabetes mellitus.</p

    The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

    Get PDF
    The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

    Get PDF
    Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies

    Initial Public Offerings and the Firm Location

    Get PDF
    The firm geographic location matters in IPOs because investors have a strong preference for newly issued local stocks and provide abnormal demand in local offerings. Using equity holdings data for more than 53,000 households, we show the probability to participate to the stock market and the proportion of the equity wealth is abnormally increasing with the volume of the IPOs inside the investor region. Upon nearly the universe of the 167,515 going public and private domestic manufacturing firms, we provide consistent evidence that the isolated private firms have higher probability to go public, larger IPO underpricing cross-sectional average and volatility, and less pronounced long-run under-performance. Similar but opposite evidence holds for the local concentration of the investor wealth. These effects are economically relevant and robust to local delistings, IPO market timing, agglomeration economies, firm location endogeneity, self-selection bias, and information asymmetries, among others. Findings suggest IPO waves have a strong geographic component, highlight that underwriters significantly under-estimate the local demand component thus leaving unexpected money on the table, and support state-contingent but constant investor propensity for risk

    Genome-wide association and Mendelian randomisation analysis provide insights into the pathogenesis of heart failure

    Get PDF
    Abstract: Heart failure (HF) is a leading cause of morbidity and mortality worldwide. A small proportion of HF cases are attributable to monogenic cardiomyopathies and existing genome-wide association studies (GWAS) have yielded only limited insights, leaving the observed heritability of HF largely unexplained. We report results from a GWAS meta-analysis of HF comprising 47,309 cases and 930,014 controls. Twelve independent variants at 11 genomic loci are associated with HF, all of which demonstrate one or more associations with coronary artery disease (CAD), atrial fibrillation, or reduced left ventricular function, suggesting shared genetic aetiology. Functional analysis of non-CAD-associated loci implicate genes involved in cardiac development (MYOZ1, SYNPO2L), protein homoeostasis (BAG3), and cellular senescence (CDKN1A). Mendelian randomisation analysis supports causal roles for several HF risk factors, and demonstrates CAD-independent effects for atrial fibrillation, body mass index, and hypertension. These findings extend our knowledge of the pathways underlying HF and may inform new therapeutic strategies
    corecore