1,720,965 research outputs found
Mast Cell Response to Influenza A Infection and Their Antiviral Activity in Co-culture with Epithelial Cells
Get PDFWell known their role in allergic inflammation, mast cells (MC) are also important in innate immunity against pathogens. MC are abundant in the respiratory tract and in close proximity to epithelial cells (EC) where they could be important in host defenses or the pathogenesis of viral infections such as with influenza A (FluA). However, little is known about the roles of MC in viral infections of the airways.
To investigate, the potential role of MC in FluA infections, we measured short-term mediator release of MC and found that they release histamine, β-hexosaminidase and prostaglandin D2 following exposure to selected strains of FluA. Of several cytokines and chemokines studied, MC only released CCL-4 after FluA exposure, whereas EC released CCL-5, CXCL-10 and type III interferon. Since it was previously shown that following FluA infection, MC produce few new FluA progeny, we investigated expression of selected antiviral genes in MC and EC at several different time points. FluA exposure induced the expression of RIG-I and MDA5 mRNA in MC, but only Viperin in EC. Neither EC nor MC had increased expression of MAVS mRNA.
We co-cultured FluA-exposed EC with or without MC. When MC were present, FluA release from EC was decreased. In co-culture, this was associated with increased release of Flt-3L and CCL-4. We also determined that bottom chamber supernatants from co-cultures with FluA-exposed EC inhibited FluA release from EC. Heat treatment (100°C) and protease digestion eliminated the antiviral activity in supernatants derived from MC. We determined the molecular size of the antiviral activity to be greater than 10 kDa and to have a relatively strong positive charge with a weak negative charge. Preliminary results from mass spectrometric studies of MC-derived antiviral supernatants showed strong signals of keratin. Despite not precisely identifying the nature of the antiviral activity, we gained a better understanding of MC in antiviral immunity and their collaboration with EC
The perplexity of calcium-binding protein, spermatid-associated 1 (CABS1): A molecule that despite its name, is present beyond the reproductive tract, with ties to stress, and possessing an anti-inflammatory domain only preserved in simians
Get PDFA protein in rat submandibular glands (SMG) led our group to research human calcium-binding protein, spermatid associated 1 (CABS1). In a model of lung inflammation in rats where neural input was interrupted, our group observed that SMG released an anti-inflammatory factor later identified as Submandibular rat protein 1 (SMR1). Rat SMR1 was present in serum, saliva, testes, and SMG. A seven amino acid peptide near the carboxyl terminus of SMR1, TDIFEGG, was responsible for the anti-inflammatory activity. Synthetic TDIFEGG and derivates had anti-inflammatory activity in several animal models, but a human trial in mild atopic asthma showed no significant effect. SMR1 is absent in humans, but we postulated that an analogous pathway existed. Thus, our group looked for a human protein that contained a similar peptide sequence, ultimately finding CABS1, which has the seven-peptide sequence, TDIFELL, also near the carboxyl terminus.
CABS1 has been characterized previously in testes of rat, mouse, and pig. Transcript has been found in testes, uterus, and salivary glands of mammals. Previously, our group showed CABS1 protein in human (h) SMG, lungs, testes, and saliva via Western blots (WB) using a single polyclonal antibody. The data suggested that hCABS1 exists as several variants of different molecular weight. A 27 kDa band in saliva positively correlated to perceived psychosocial stress, and bands <27 kDa could be indicators of resilience to stress. Based on these data, my hypotheses were that hCABS1 is present beyond the testes, in SMG, saliva and blood, like rat SMR1, and that variants of CABS1 in saliva are biomarkers of stress.
To extend our previous findings, we analyzed WB profiles using four pAbs to hCABS1 and overexpression cell lysate controls, SMG, and saliva. We used these profiles as guidance to isolate in-gel sections that we speculated contained hCABS1 and evaluated their protein content through mass spectrometry sequencing (MS-seq). hCABS1 was detected in overexpression cell lysates via MS-seq, yet contrary to what our WB profiles, to date we have not detected the protein in human-derived biofluids or tissue extracts.
Given the limiting amounts of pAbs available, a capillary nano-immunoassay (CNIA) was used to validate the occurrence of hCABS1 variants in saliva. With this platform, we successfully validated our previous stress-related findings, and also reported another variant of hCABS1 (60 kDa) in saliva detected by a pAb that targets TDIFELL. CNIA optimization also led to improvements in our WB protocol that encouraged reevaluation of our previous data in saliva. WB analysis using pAbs allowed us to target sites in one and two-dimensional gels for MS-seq analysis. However, efforts to confirm the presence of hCABS1 in saliva using MS-seq were unsuccessful, perhaps because of limitations in our pAbs or the amount of hCABS1. We speculated that the pAb detected hCABS1 and potentially other protein(s), and thus developed monoclonal antibodies (mAbs) targeting three domains of the protein. Using these mAbs, WB analyses of overexpression cell lysate controls, SMG, saliva and serum detected fewer bands than pAbs, but validated that hCABS1 is present beyond the testicular compartment.
We also conducted immunohistochemical (IHC) analyses of SMG with four pAbs and one mAb, showing that hCABS1 is present in the cytoplasm of duct cells of SMG. IHC of human testis, suggest that hCABS1 is present in cytoplasm of primary spermatogonia in seminiferous tubules and outside the tubules in Leydig cells. Moreover, we have begun to immunoprecipitate hCABS1 from a transient overexpression cell lysate with our mAbs, and have confirmed success using MS-seq.
We have further dissected the protein using in silico analyses. These studies provide evidence of disordered domains close to the carboxyl terminus of hCABS1, where its anti-inflammatory domain is located, as well as in other segments of the protein. A phylogenetic analysis showed that the peptide sequence, TDIFELL, is found exclusively in primates of the infraorder Simiiformes, which includes humans. Supporting our WB work, a predicted degradome analysis of hCABS1 with neutrophil elastase identified several potential cleavage sites, theoretically generating hCABS1-derived peptides. Altogether, evidence in this dissertation supports the presence of hCABS1 beyond the testes, in SMG and blood. However, evidence about hCABS1 in saliva is inconclusive and thus the link to stress remains to be clarified
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
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
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