78 research outputs found

    Recovery of forearm and fine digit function after chronic spinal cord injury by simultaneous blockade of inhibitory matrix CSPG production and the receptor PTPσ

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    Spinal cord injuries (SCI), for which there are limited effective treatments, result in enduring paralysis and hypoesthesia, in part because of the inhibitory microenvironment that develops and limits regeneration/sprouting, especially during chronic stages. Recently, we discovered that targeted enzymatic removal of the inhibitory chondroitin sulfate proteoglycan (CSPG) component of the extracellular and perineuronal net (PNN) matrix via Chondroitinase ABC (ChABC) rapidly restored robust respiratory function to the previously paralyzed hemi-diaphragm after remarkably long times post-injury (up to 1.5 years) following a cervical level 2 lateral hemi-transection. Importantly, ChABC treatment at cervical level 4 in this chronic model also elicited improvements in gross upper arm function. In the present study, we focused on arm and hand function, seeking to highlight and optimize crude as well as fine motor control of the forearm and digits at lengthy chronic stages post-injury. However, instead of using ChABC, we utilized a novel and more clinically relevant systemic combinatorial treatment strategy designed to simultaneously reduce and overcome inhibitory CSPGs. Following a 3-month upper cervical spinal hemi-lesion using adult female Sprague Dawley rats, we show that the combined treatment had a profound effect on functional recovery of the chronically paralyzed forelimb and paw, as well as on precision movements of the digits. The regenerative and immune system related events that we describe deepen our basic understanding of the crucial role of CSPG-mediated inhibition via the PTPσ receptor in constraining functional synaptic plasticity at lengthy time points following SCI, hopefully leading to clinically relevant translational benefits

    Metadata for Scientific Experiment Reporting: A Case Study in Metal-Organic Frameworks

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    Research methods and procedures are core aspects of the research process. Metadata focused on these components is critical to supporting the FAIR principles, particularly reproducibility. The research reported on in this paper presents a methodological framework for metadata documentation supporting the reproducibility of research producing Metal Organic Frameworks (MOFs). The MOF case study involved natural language processing to extract key synthesis experiment information from a corpus of research literature. Following, a classification activity was performed by domain experts to identify entity-relation pairs. Results include: 1) a research framework for metadata design, 2) a metadata schema that includes nine entities and two relationships for reporting MOF synthesis experiments, and 3) a growing database of MOF synthesis reports structured by our metadata scheme. The metadata schema is intended to support discovery and reproducibility of metal-organic framework research and the FAIR principles. The paper provides background information, identifies the research goals and objectives, research design, results, a discussion, and the conclusion.Comment: Accepted by the 17th International Conference on Metadata and Semantics Researc

    Building Open Knowledge Graph for Metal-Organic Frameworks (MOF-KG): Challenges and Case Studies

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    Metal-Organic Frameworks (MOFs) are a class of modular, porous crystalline materials that have great potential to revolutionize applications such as gas storage, molecular separations, chemical sensing, catalysis, and drug delivery. The Cambridge Structural Database (CSD) reports 10,636 synthesized MOF crystals which in addition contains ca. 114,373 MOF-like structures. The sheer number of synthesized (plus potentially synthesizable) MOF structures requires researchers pursue computational techniques to screen and isolate MOF candidates. In this demo paper, we describe our effort on leveraging knowledge graph methods to facilitate MOF prediction, discovery, and synthesis. We present challenges and case studies about (1) construction of a MOF knowledge graph (MOF-KG) from structured and unstructured sources and (2) leveraging the MOF-KG for discovery of new or missing knowledge.Comment: Accepted by the International Workshop on Knowledge Graphs and Open Knowledge Network (OKN'22) Co-located with the 28th ACM SIGKDD Conferenc

    Anemia de células falciformes en pediatría: Revisión de la literatura

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    Introduction: Sickle cell anemia is a structural hemoglobinopathy of genetic origin, characterized by the presence of sickle hemoglobin. Abnormal hemoglobin is unstable and tends to polymerize and can occlude the microcirculation. Also, it produces both acute and chronic multi system manifestations associated with an increased risk of infection. Objective: To describe the information of the exposed topic highlighting the most relevant aspects such as diagnosis and treatment. Methodology: A literature review with electronic search was carried out in the following databases: PubMed, MEDLINE, Medscape, Scopus; different types of articles were included that addressed sickle cell anemia in pediatrics such as original articles, reviews of topics and management. Results: A review of 22 articles was obtained which describes the subject of sickle cell anemia, guidelines and treatments based on the management and control of symptoms. It is evident that the use of transcranial Doppler ultrasound and transfusions proved to be preventive strategies or effective treatments for the complications related to this pathology in children. Conclusions: In Colombia, the prevalence of the pathology is not established yet. On the other hand, the main manifestations are related to complications of vaso-occlusion in different organs and functional asplenia which predisposes to infectious conditions. [Tirado-Pérez IS, Zárate Vergara AC. Sickle Cell Anemia in Pediatrics: Literature review. MedUNAB 2017-2018; 20(3): 374-382].Introducción: La anemia falciforme es una hemoglobinopatía estructural de origen genético, se caracteriza por la presencia de hemoglobina falciforme. La hemoglobina anormal es inestable, tiende a polimerizarse y puede ocluir la microcirculación, produciendo manifestaciones multisistémicas tanto agudas como crónicas relacionándose con mayor riesgo de contraer infecciones. Objetivo: Describir la información del tema expuesto resaltando los aspectos más relevantes como diagnóstico y tratamiento. Metodología: Se efectuó una revisión bibliográfica con búsqueda electrónica en las siguientes bases de datos: PubMed, MEDLINE, Medscape, Scopus; y se incluyó diferentes tipos de artículo (artículos originales, revisiones de temas y guías de manejo) que abordaran la anemia de células falciformes en pediatría. Resultados: Se obtuvo una revisión de 22 artículos, donde se describe el tema de anemia de células falciformes, pautas y tratamientos basados en el manejo y control de los síntomas; se evidencia que el uso de ecografía doppler transcraneal y las transfusiones demostraron ser estrategias preventivas o de tratamiento eficaces para las complicaciones relacionadas con esta patología en los niños. Conclusiones: En Colombia, la prevalencia de la patología no se encuentra establecida. Por otra parte, las principales manifestaciones se relacionan con complicaciones de vaso-oclusión en los diferentes órganos y la asplenia funcional, la cual predispone a cuadros infecciosos. [Tirado-Pérez IS, Zárate Vergara AC. Anemia de células falciformes en pediatría: Revisión de la literatura. Revisión de tema. MedUNAB 2017-2018; 20(3): 374-382]

    Geography and the Paris Academy of Sciences: politics and patronage in early 18th-century France

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    This essay considers the politics and patronage of geography in early-modern France. It examines how the Paris Academy of Sciences, widely acknowledged as the 18th century’s pre-eminent scientific society, came to recognise geography as an independent science in 1730, a century before the establishment of the first geographical societies. Although the Academy was centrally concerned with cartography from its inception in 1666, it initially afforded no official status to geography, which was viewed either as a specialised form of historical inquiry or as a minor component within the hegemonic science of astronomy. The rise of Newtonian mathematics and the associated controversy about the shape of the earth challenged the Academy’s epistemological foundations and prompted a debate about the educational and political significance of geography as a scientific practice. The death in 1726 of Guillaume Delisle, a prominent Academy astronomer-cartographer and a popular geography tutor to the young Louis XV, led to a spirited campaign to elect Philippe Buache, Delisle’s prot�eg�e, to a new Academy position as a geographer rather than an astronomer. The campaign emphasised the social and political utility of geography, though the Academy’s decision to recognise this new and distinctively modern science was ultimately facilitated by traditional networks of patronage within the French Royal Court

    Infrared light elicits endothelium-dependent vasodilation in isolated occipital arteries of the rat via soluble guanylyl cyclase-dependent mechanisms

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    The left and right occipital arteries provide blood supply to afferent cell bodies in the ipsilateral nodose and petrosal ganglia. This supply is free of an effective blood-ganglion barrier, so changes in occipital artery blood flow directly affect the access of circulating factors to the afferent cell bodies. The application of infrared (IR) light to modulate neural and other cell processes has yielded information about basic biological processes within tissues and is gaining traction as a potential therapy for a variety of disease processes. To address whether IR can directly modulate vascular function, we performed wire myography studies to determine the actions of IR on occipital arteries isolated from male Sprague-Dawley rats. Based on our previous research that functionally-important differences exist between occipital artery segments close to their origin at the external carotid artery (ECA) and those closer to the nodose ganglion, the occipital arteries were dissected into two segments, one closer to the ECA and the other closer to the nodose ganglion. Segments were constricted with 5-hydroxytryptamine to a level equal to 50% of the maximal response generated by the application of a high (80 mM) concentration of K+ ions. The direct application of pulsed IR (1,460 nm) for 5 s produced a rapid vasodilation in occipital arteries that was significantly more pronounced in segments closest to the ECA, although the ECA itself was minimally responsive. The vasodilation remained for a substantial time (at least 120 s) after cessation of IR application. The vasodilation during and following cessation of the IR application was markedly diminished in occipital arteries denuded of the endothelium. In addition, the vasodilation elicited by IR in endothelium-intact occipital arteries was substantially reduced in the presence of a selective inhibitor of the nitric oxide-sensitive guanylate cyclase, 1H-[1,2,4]oxadiazolo [4,3-a]quinoxalin-1-one (ODQ). It appears that IR causes endothelium-dependent, nitric-oxide-mediated vasodilation in the occipital arteries of the rat. The ability of IR to generate rapid and sustained vasodilation may provide new therapeutic approaches for restoring or improving blood flow to targeted tissues

    Development of a rhesus monkey lung geometry model and application to particle deposition in comparison to humans

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    The exposure-dose-response characterization of an inhalation hazard established in an animal species needs to be translated to an equivalent characterization in humans relative to comparable doses or exposure scenarios. Here, the first geometry model of the conducting airways for rhesus monkeys is developed based upon CT images of the conducting airways of a 6-month-old male, rhesus monkey. An algorithm was developed for adding the alveolar region airways using published rhesus morphometric data. The resultant lung geometry model can be used in mechanistic particle or gaseous dosimetry models. Such dosimetry models require estimates of the upper respiratory tract volume of the animal and the functional residual capacity, as well as of the tidal volume and breathing frequency of the animal. The relationship of these variables to rhesus monkeys of differing body weights was established by synthesizing and modeling published data as well as modeling pulmonary function measurements on 121 rhesus control animals. Deposition patterns of particles up to 10 μm in size were examined for endotracheal and and up to 5 μm for spontaneous breathing in infant and young adult monkeys and compared to those for humans. Deposition fraction of respirable size particles was found to be higher in the conducting airways of infant and young adult rhesus monkeys compared to humans. Due to the filtering effect of the conducting airways, pulmonary deposition in rhesus monkeys was lower than that in humans. Future research areas are identified that would either allow replacing assumptions or improving the newly developed lung model

    Interpreting the role of de novo protein-coding mutations in neuropsychiatric disease

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    Pedigree, linkage and association studies are consistent with heritable variation for complex disease due to the segregation of genetic factors in families and in the population. In contrast, de novo mutations make only minor contributions to heritability estimates for complex traits. Nonetheless, some de novo variants are known to be important in disease etiology. The identification of risk-conferring de novo variants will contribute to the discovery of etiologically relevant genes and pathways and may help in genetic counseling. There is considerable interest in the role of such mutations in complex neuropsychiatric disease, largely driven by new genotyping and sequencing technologies. An important role for large de novo copy number variations has been established. Recently, whole-exome sequencing has been used to extend the investigation of de novo variation to point mutations in protein-coding regions. Here, we consider several challenges for the interpretation of such mutations in the context of their role in neuropsychiatric disease

    Detecting Clusters of Mutations

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    Positive selection for protein function can lead to multiple mutations within a small stretch of DNA, i.e., to a cluster of mutations. Recently, Wagner proposed a method to detect such mutation clusters. His method, however, did not take into account that residues with high solvent accessibility are inherently more variable than residues with low solvent accessibility. Here, we propose a new algorithm to detect clustered evolution. Our algorithm controls for different substitution probabilities at buried and exposed sites in the tertiary protein structure, and uses random permutations to calculate accurate P values for inferred clusters. We apply the algorithm to genomes of bacteria, fly, and mammals, and find several clusters of mutations in functionally important regions of proteins. Surprisingly, clustered evolution is a relatively rare phenomenon. Only between 2% and 10% of the genes we analyze contain a statistically significant mutation cluster. We also find that not controlling for solvent accessibility leads to an excess of clusters in terminal and solvent-exposed regions of proteins. Our algorithm provides a novel method to identify functionally relevant divergence between groups of species. Moreover, it could also be useful to detect artifacts in automatically assembled genomes

    Maria Cosway’s Hours: Cosmopolitan and Classical Visual Culture in Thomas Macklin’s Poets Gallery

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    Thomas Macklin’s Gallery of Poets opened at the Mitre Tavern in Fleet Street in 1788 with the aim to ‘display British Genius’ through ‘Prints Illustrative of the Most Celebrated British Poets’. Early newspaper coverage promised ‘a monument of the powers of the pencil in England, as the Vatican is at Rome’. The incongruous juxtaposition between Fleet Street and the Vatican spells out the cosmopolitan ambition of the literary gallery phenomenon through its real and imagined geographies of display. Through the format of the paper gallery of prints, Macklin’s Poets offered the inventions of British Poets as a repository of painting. This chapter examines how the cosmopolitan idiom of the paper gallery is negotiated in the first number of Macklin’s Poets. This essay examines the extent to which this ambition was achieved in the first Number of Macklin’s Poets which carried an engraving of Maria Cosway’s The Hours, originally a painting with an impressively European iconographic heritage. The painting was first exhibited at the Royal Academy in 1783, and was retroactively associated by Macklin with Thomas Gray’s ‘Ode on the Spring’. The trope of the Hours brought with it a weighty provenance derived from classical marble bas-relief, through the antiquarian pages of Pietro Santi Bartoli and Bernard de Montfaucon to Flaxman’s designs for Wedgwood plaques and vases. Cosway’s name also imported into Gray’s poem her reputation as a cosmopolitan, cultured woman who had completed the Grand Tour and who moved in elite circles including those of the Prince of Wales in London and the Duke of Orleans, Pierre d’Hancarville and Thomas Jefferson in Paris. The iconographies of the painting, the print, and the poem articulate a European cosmopolitan tradition for British Art
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