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Phagocytose par les macrophages humains : modulation par le microenvironnement et par les rhinovirus humains
No full textLa phagocytose est le mécanisme d'internalisation et de dégradation de particules de grande taille, comme les microorganismes et les débris cellulaires. Ce processus est crucial pour la défense de l'hôte contre des agents pathogènes ainsi que pour le remodelage tissulaire. La phagocytose commence par la reconnaissance d'une particule par des récepteurs phagocytaires, qui déclenchent des voies de signalisation aboutissant à la polymérisation d'actine responsable de l'extension de la membrane plasmique autour de la particule cible jusqu'à former un compartiment appelé le phagosome. Le phagosome est ensuite soumis à un processus appelé maturation, qui mène à la dégradation du cargo. Les macrophages sont des cellules phagocytaires professionnelles qui sont présentes dans presque tous les tissus de l'organisme. Les tissus sont des environnements complexes, dont la matrice extracellulaire fournit des signaux à la fois chimiques et mécaniques qui affectent le comportement des macrophages. En particulier, ces stimuli mécaniques sont altérés dans de nombreuses maladies. De plus, les rhinovirus humains (HRV) sont connus pour diminuer les fonctions des macrophages dans certaines maladies respiratoires chroniques, comme la bronchopneumopathie chronique obstructive (BPCO). Par conséquent, nous nous sommes demandé si la phagocytose par les macrophages peut être modulée par les propriétés mécaniques du microenvironnement et par HRV16. Nous avons montré que les fonctions d'adhérence et de phagocytose des macrophages primaires humains varient avec la rigidité de leur substrat. Afin de comprendre si la phagocytose influence la façon dont les cellules phagocytaires interagissent avec leur environnement, nous avons utilisé la microscopie de force de traction en temps réel et nous avons montré que les macrophages en train de phagocyter ont des interactions plus dynamiques avec leur substrat. La phagocytose déclenche une perte temporaire des podosomes de façon concomitante à la polymérisation d'actine à la coupe phagocytaire, et ceci est associé à une dégradation moindre de la matrice extracellulaire. Ces résultats démontrent l'existence d'une régulation réciproque entre phagocytose et adhérence chez les macrophages. Les propriétés mécaniques du microenvironnement influencent la phagocytose qui, en retour, affecte la façon dont les macrophages interagissent avec leur milieu. Par ailleurs, nous avons montré que HRV16 altère la maturation des phagosomes dans les macrophages humains. L'expression de la petite GTPase ARL5b est augmentée après exposition au virus et la déplétion de cette protéine restaure une maturation normale des phagosomes. Pour mieux comprendre comment HRV16 affecte les fonctions des macrophages, nous avons étudié si ce virus peut entrer dans ces cellules et les infecter. Nous avons montré que HRV16 est effectivement internalisé par les macrophages humains par l'intermédiaire d'un récepteur cellulaire mais qu'il ne peut pas se répliquer de façon efficace dans ces cellules. Les macrophages déclenchent également une réponse antivirale à ce virus. Dans l'ensemble, ces résultats mettent en lumière les manières dont la phagocytose par les macrophages humains est remarquablement affectée par des stimuli mécaniques du microenvironnement et par les rhinovirus humains.Phagocytosis is the mechanism of internalization and degradation of large particles, such as microorganisms and cell debris. This process is crucial for host defense against invading pathogens, as well as for tissue remodeling. Phagocytosis starts with the recognition of a particle by phagocytic receptors, which trigger signaling cascades resulting in actin polymerization that drives the extension of the plasma membrane around the target. It ultimately seals to form a closed compartment called the phagosome. The phagosome then undergoes a process called maturation, which leads to the degradation of the cargo. Macrophages are professional phagocytic cells that are present in virtually all tissues of the body. Tissues are complex environments, where the extracellular matrix provides a wide variety of both chemical and mechanical cues that affect macrophage behavior. Mechanical cues, in particular, are altered in many disease conditions. In addition, human rhinoviruses (HRVs) are known to impair macrophage functions in chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). Thus, we asked if phagocytosis by macrophages can be modulated by mechanical properties of the microenvironment and by HRV16. We found that cell adhesion and the ability of primary human macrophages to perform phagocytosis varied with the stiffness of their substrate. To understand if phagocytosis influences how phagocytic cells interact with their environment as well, we used live traction force microscopy and showed that phagocytosing macrophages have more dynamic interactions with their substrate. Furthermore, phagocytosis triggered a transient loss of podosomes concomitantly with actin polymerization at the phagocytic cup, and this was associated with decreased degradation of the extracellular matrix. Overall, these results highlight the existence of a crosstalk between phagocytosis and cell adhesion in macrophages. Mechanical properties of the microenvironment influence phagocytosis, which, in turn, impacts how macrophages interact with their immediate surroundings. Furthermore, we showed that HRV16 impairs phagosome maturation in human macrophages. Small GTPase ARL5b was found to be up-regulated by the virus and depletion of this protein restored normal phagosome maturation in macrophages upon HRV16 exposure. To better understand how HRV16 might affect macrophage functions, we then studied whether HRV16 could actually enter and infect these cells. We showed that HRV16 was internalized by human macrophages through receptor-mediated uptake but that it cannot efficiently replicate inside these cells. Macrophages also mounted an antiviral response to the virus. Taken together, these results shed new light on how phagocytosis by human macrophages is uniquely affected by mechanical cues from the microenvironment and by human rhinoviruses
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Phagocytose par les macrophages humains : modulation par le microenvironnement et par les rhinovirus humains
No full textPhagocytosis is the mechanism of internalization and degradation of large particles, such as microorganisms and cell debris. This process is crucial for host defense against invading pathogens, as well as for tissue remodeling. Phagocytosis starts with the recognition of a particle by phagocytic receptors, which trigger signaling cascades resulting in actin polymerization that drives the extension of the plasma membrane around the target. It ultimately seals to form a closed compartment called the phagosome. The phagosome then undergoes a process called maturation, which leads to the degradation of the cargo. Macrophages are professional phagocytic cells that are present in virtually all tissues of the body. Tissues are complex environments, where the extracellular matrix provides a wide variety of both chemical and mechanical cues that affect macrophage behavior. Mechanical cues, in particular, are altered in many disease conditions. In addition, human rhinoviruses (HRVs) are known to impair macrophage functions in chronic respiratory diseases, such as chronic obstructive pulmonary disease (COPD). Thus, we asked if phagocytosis by macrophages can be modulated by mechanical properties of the microenvironment and by HRV16. We found that cell adhesion and the ability of primary human macrophages to perform phagocytosis varied with the stiffness of their substrate. To understand if phagocytosis influences how phagocytic cells interact with their environment as well, we used live traction force microscopy and showed that phagocytosing macrophages have more dynamic interactions with their substrate. Furthermore, phagocytosis triggered a transient loss of podosomes concomitantly with actin polymerization at the phagocytic cup, and this was associated with decreased degradation of the extracellular matrix. Overall, these results highlight the existence of a crosstalk between phagocytosis and cell adhesion in macrophages. Mechanical properties of the microenvironment influence phagocytosis, which, in turn, impacts how macrophages interact with their immediate surroundings. Furthermore, we showed that HRV16 impairs phagosome maturation in human macrophages. Small GTPase ARL5b was found to be up-regulated by the virus and depletion of this protein restored normal phagosome maturation in macrophages upon HRV16 exposure. To better understand how HRV16 might affect macrophage functions, we then studied whether HRV16 could actually enter and infect these cells. We showed that HRV16 was internalized by human macrophages through receptor-mediated uptake but that it cannot efficiently replicate inside these cells. Macrophages also mounted an antiviral response to the virus. Taken together, these results shed new light on how phagocytosis by human macrophages is uniquely affected by mechanical cues from the microenvironment and by human rhinoviruses.La phagocytose est le mécanisme d'internalisation et de dégradation de particules de grande taille, comme les microorganismes et les débris cellulaires. Ce processus est crucial pour la défense de l'hôte contre des agents pathogènes ainsi que pour le remodelage tissulaire. La phagocytose commence par la reconnaissance d'une particule par des récepteurs phagocytaires, qui déclenchent des voies de signalisation aboutissant à la polymérisation d'actine responsable de l'extension de la membrane plasmique autour de la particule cible jusqu'à former un compartiment appelé le phagosome. Le phagosome est ensuite soumis à un processus appelé maturation, qui mène à la dégradation du cargo. Les macrophages sont des cellules phagocytaires professionnelles qui sont présentes dans presque tous les tissus de l'organisme. Les tissus sont des environnements complexes, dont la matrice extracellulaire fournit des signaux à la fois chimiques et mécaniques qui affectent le comportement des macrophages. En particulier, ces stimuli mécaniques sont altérés dans de nombreuses maladies. De plus, les rhinovirus humains (HRV) sont connus pour diminuer les fonctions des macrophages dans certaines maladies respiratoires chroniques, comme la bronchopneumopathie chronique obstructive (BPCO). Par conséquent, nous nous sommes demandé si la phagocytose par les macrophages peut être modulée par les propriétés mécaniques du microenvironnement et par HRV16. Nous avons montré que les fonctions d'adhérence et de phagocytose des macrophages primaires humains varient avec la rigidité de leur substrat. Afin de comprendre si la phagocytose influence la façon dont les cellules phagocytaires interagissent avec leur environnement, nous avons utilisé la microscopie de force de traction en temps réel et nous avons montré que les macrophages en train de phagocyter ont des interactions plus dynamiques avec leur substrat. La phagocytose déclenche une perte temporaire des podosomes de façon concomitante à la polymérisation d'actine à la coupe phagocytaire, et ceci est associé à une dégradation moindre de la matrice extracellulaire. Ces résultats démontrent l'existence d'une régulation réciproque entre phagocytose et adhérence chez les macrophages. Les propriétés mécaniques du microenvironnement influencent la phagocytose qui, en retour, affecte la façon dont les macrophages interagissent avec leur milieu. Par ailleurs, nous avons montré que HRV16 altère la maturation des phagosomes dans les macrophages humains. L'expression de la petite GTPase ARL5b est augmentée après exposition au virus et la déplétion de cette protéine restaure une maturation normale des phagosomes. Pour mieux comprendre comment HRV16 affecte les fonctions des macrophages, nous avons étudié si ce virus peut entrer dans ces cellules et les infecter. Nous avons montré que HRV16 est effectivement internalisé par les macrophages humains par l'intermédiaire d'un récepteur cellulaire mais qu'il ne peut pas se répliquer de façon efficace dans ces cellules. Les macrophages déclenchent également une réponse antivirale à ce virus. Dans l'ensemble, ces résultats mettent en lumière les manières dont la phagocytose par les macrophages humains est remarquablement affectée par des stimuli mécaniques du microenvironnement et par les rhinovirus humains
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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