1,720,955 research outputs found
Host-microorganism interactions in obesity and colorectal cancer
Full text linkNowadays colorectal cancer (CRC) is a threat to global health. The data collected by the Global Cancer Observatory (GCO) report that CRC is the third most common cancer and the second cause of tumor-associated mortality in the world. The early diagnosis of CRC is very hard and the screening methods currently used in the clinical practise have several limitations. This has stimulated intense research aimed to find sensitive, non-invasive and early biomarkers in easily collectable matrices. Both non-modifiable and modifiable factors can increase the risk of developing CRC. Among lifestyle-related factors obesity, as result of excessive caloric intake and sedentary life, is a predominant risk factor for colorectal carcinogenesis. The progressive increase in CRC incidence correlates with overweight and obesity epidemic proportion, consistently with the evidence of a positive correlation between body mass index (BMI) and CRC risk. A decrease of cancer incidence is recorded after bariatric surgery (BS) that is considered the most efficient treatment to lose weight in case of severe obesity. White adipose tissue (AT) is the first target organ in obesity being characterised by metabolic derangements, a low-grade of chronic inflammation and oxidative stress. By phosphoproteomics analysis, we investigated the profile of DNA damage response (DDR) and senescence markers in AT of subjects with severe obesity, compared to the normal weight controls. A higher protein activation/expression of DDR players and senescence markers was found in AT of patients affected by obesity. Notably, the concurrent DDR and cellular senescence activation was observed in visceral AT (VAT), but not in subcutaneous AT (SAT), in agreement with the known association between VAT expansion and comorbidities development. All these data, associated to the elevated systemic levels of inflammatory and oxidative markers, observed in the plasma of our patients, align with the onset of a senescent-associated secretory phenotype (SASP). Interestingly, after BS, a significant reduction of systemic pro-inflammatory cytokines, a restoration of adipokines secretion and a significant reduction of plasmatic ccf-mtDNA, as a damage-associated molecular pattern (DAMP), have been recorded thus testifying the achievement of a healthier profile of subjects affected by severe obesity. Dysbiosis, commonly observed in obesity, concurs to CRC development and could be proposed as a potential therapeutic target and biomarker with both predictive and prognostic value. We characterized both gut and oral bacterial microbiomes in individuals affected by obesity and CRC patients with the aim to identify common and distinct microbial profiles. In parallel, the prevalence of specific oral human DNA viruses, potentially associated with CRC, was analyzed in CRC patients and in subject groups at high CRC risk, such as individuals with obesity or with nonfamilial colon adenomatous polyposis (AP). The prevalence of the same infections was also analyzed in obese individuals after BS to investigate whether weight loss could affect the oral viral profile. We found the same trend of modulation in obesity and CRC for most bacterial genera, both in the gut and in the oral cavity. Our results also show a significantly higher prevalence of oral beta-Human Papilloma Viruses (HPV) and beta-HPV multiple infections in CRC patients, and a trend of increase in high-risk groups. Furthermore, the prevalence of specific beta HPV genotypes was found associated to both BMI and pathological conditions. Notably, a lower prevalence of all beta HPVs and of specific genotypes was observed in obese patients after bariatric surgery suggesting that the surgery-related benefits can reduce the persistence of viral agents potentially involved in CRC risk increase. Given the increase of Proteobacteria (such as E. coli or S. enterica) and the reduction of Verrucomicrobiota (such as A. muciniphila) found in the gut microbiome of both subjects with obesity and CRC patients, we investigated the effects of endotoxins from pathogenic and commensal/probiotic bacteria on the generation and function of human dendritic cells (DC) and DC/γδ T lymphocyte crosstalk in an in vitro study on healthy donors. We found that A. muciniphila LPS can promote the differentiation of DC with full immunostimulatory properties, in contrast to comparable concentrations of LPS derived from E. coli and S. enterica, which can create an immunosuppressive environment. According to the obtained results, alterations of oral and intestinal microbiome seem to be a causative bridge between obesity and CRC, but larger cohorts and deeper analysis are necessary to draw a definitive link
Akkermansia muciniphila- and Pathogenic Bacteria-Derived Endotoxins Differently Regulate Human Dendritic Cell Generation and γδ T Lymphocyte Activation
No full textLipopolysaccharide (LPS) is a potent endotoxin released at high concentrations in acute infections, causing massive host inflammatory response. Accumulating evidence indicates that dysbiosis-associated chronic low levels of circulating LPS can sustain a prolonged sterile low-grade inflammation that increases the risk of several non-communicable diseases. Interventions aimed at increasing the abundance of beneficial/probiotic bacteria, including Akkermansia muciniphila, result in reduced inflammation, favoring metabolic and immune health. Immunosuppression is a common feature in conditions of chronic inflammation, and dendritic cells (DCs) represent key targets given their ability to shift the balance toward immunity or tolerance. In this study, the effects of low concentrations of LPS from pathogenic (Escherichia coli and Salmonella enterica) and probiotic (Akkermansia muciniphila) bacterial species on human DC generation and functions were compared. We report that monocyte precursor priming with Escherichia coli and Salmonella enterica LPS forces the differentiation of PD-L1-expressing DCs, releasing high levels of IL-6 and IL-10, and impairs their capacity to drive full TCR-Vδ2 T cell activation. Conversely, comparable concentrations of Akkermansia muciniphila promoted the generation of DCs with preserved activating potential and immunostimulatory properties. These results shed light on potential mechanisms underlying the impact of low endotoxemia on disease risk and pathogenesis, and increase our understanding of the immunomodulatory effects of Akkermansia muciniphila
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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