1,721,023 research outputs found
What is new about diet in hepatic encephalopathy
Full text linkThere is a relationship between hepatic encephalopathy (HE) protein malnutrition and muscle wasting. Muscle may play an alternative role in ammonia detoxification. Molecular mechanisms responsible for muscle depletion are under investigation. Specific nutrients may interact to reverse the molecular pathways involved in muscle wasting at an early stage. Training exercises have also been proposed to improve skeletal muscle mass. However, these data refer to small groups of patients. The amelioration of muscle mass may potentially help to prevent HE. The pathogenesis of HE is associated with modifications of the gut microbiota and diet is emerging to play a relevant role in the modulation of the gut milieu. Vegetarian and fibre-rich diets have been shown to induce beneficial changes on gut microbiota in healthy people, with reduction of Bacteroides spp., Enterobacteriaceae, and Clostridium cluster XIVa bacteria. By way of contrast, it has been suggested that a high-fat or protein diet may increase Firmicutes and reduce Bacteroidetes phylum. Milk-lysozyme and milk-oligosaccharides have also been proposed to induce a "healthy" microbiota. At present, no studies have been published describing the modification of the gut microbiota in cirrhotic patients with HE as a response to specific diets. New research is needed to evaluate the potentiality of foods in the modulation of gut microbiota in liver disease and HE
GUT MICROBIOTA AND THE IMMUNE SYSTEM: AN INTIMATE PARTNERSHIP IN HEALTH AND DISEASE
No full textIn recent years there have been increased rates of autoimmune diseases, possibly associated to altered intestinal microflora. In this brief review article, after a description of the structure and function of the gut microbiota organ and its cross-talk with the human host, we give a report on findings indicating how the host immune system responds to bacterial colonization of the gastrointestinal tract. The disturbances in the bacterial microbiota will result in the deregulation of adaptive immune cells, which may underlie autoimmune disorders. The mammalian immune system, which seems to be designed to control microorganisms, could be instead influenced by microorganisms, as suggested in recent literature. Alterations in both the structure and function of intestinal microbiota could be one of the 'common causative triggers' of autoimmune and/or autoinflammatory disorders
The Microbiota in Inflammatory Bowel Disease in Different Age Groups
No full textBackground: Many efforts were made in the past decades to assess the role of gut microbiota in inflammatory bowel diseases (IBD), leading to the hypothesis that an altered microbial composition, other than the presence of a specific pathogen, could be involved in the pathogenesis of the disease. On the other hand, existing differences in gut microbial community between distinct classes of age make sense of an increasing research in microbial shifts in IBD. Methods: Cultural, molecular, metabolomic and metagenomic approaches are trying to define the human gut microbiota in different age groups. Results and Conclusion: An increase in anaerobic bacteria (Bacteroides vulgatus, Streptococcus faecalis) was observed in adult IBD, whereas an increase in aerobic and facultative-anaerobic (Escherichia coli) was found in pediatric IBD. Overall higher bacterial cell counts were observed in IBD, jointly with a general loss of biodiversity and a preponderance of Bacteroidetes and a parallel decrease of Firmicutes phylum : a predominance of potential harmful members of Proteobacteria (E. coli) and low abundance of beneficial species (Faecalibacterium prausnitzii) was also reported in pediatric and adult age groups, respectively. Microbial community of elderly subjects contains a wider range of different species than those of children and adults, both in healthy and IBD status. Copyright (C) 2009 S. Karger AG, Base
Gut microbiota and pediatric disease
No full textBackground: Researchers have made every effort to assess the role of gut microbiota in pediatric diseases like inflammatory bowel disease (IBD), celiac disease, asthma, allergy, and autism. The leading hypothesis is that an altered microbial composition is present (other than the presence of a specific pathogen) and that it could be involved in the pathogenesis or progression of such disorders. Methods: Cultural, molecular, metabolomic, and metagenomic approaches are trying to define the pediatric gut microbiota imbalances in different diseases. Results and Conclusion: In pediatric IBD, a marked increase in aerobes and facultative anaerobes was found, along with an increase in Enterobacteriaceae members (Escherichia coli). In both pediatric IBD and celiac disease (Th1-mediated disorders), higher bacterial cell counts were observed, jointly with a general gain of biodiversity. A preponderance of Bacteroidetes and a parallel decrease of Firmicutes was also reported in IBD, celiac disease and autism. Contrarily, dietary changes due to Western lifestyles increase Firmicutes populations and lower short-chain fatty acids production, possibly exposing 'developed' children to the infectious challenge (Escherichia and Shigella spp.). Lactobacillus and Bifidobacterium species could be protective agents for atopic diseases, while Clostridia, Enterobacteriaceae, and staphylococci can be associated with an increased risk of such Th2-mediated disorders. In the brain-gut axis view, gut microbiota could also play a role in autism. Copyright (C) 2011 S. Karger AG, Base
Microbiological and molecular characterization of nosocomial and community Staphylococcus aureus isolates
No full textThis study aimed to evaluate the incidence of Staphylococcus aureus infections in different departments of Belcolle Hospital in Viterbo and the surrounding area between January 2003 and June 2008. Isolates of methicillin-resistant S. aureus (MRSA) recovered in this time interval were characterized by microbiological and molecular methods to evaluate the reliability of simple criteria to distinguish between hospital-acquired and community-acquired isolates. MRSA accounted for 33% of all S. aureus, with a significantly higher prevalence in isolates from nosocomial infections. MRSA isolates were assayed by PCR for the presence of 13 genes associated with virulence, agr type and SCCmec type. Cumulative data were analysed by partial least square discriminant analysis and a clear correlation was demonstrated between genetic profiles and classification of isolates as hospital or community acquired according to simple temporal criteria. Nosocomial MRSA isolates from blood samples showed significantly higher genetic diversity than other nosocomial isolates. Our data confirm the existence of significant differences between community- and hospital-acquired MRSA isolates
Microbiota and the gut-liver axis: bacterial translocation, inflammation and infection in cirrhosis
Full text linkLiver disease is associated with qualitative and quanti- tative changes in the intestinal microbiota. In cirrhotic patients the alteration in gut microbiota is characterized by an overgrowth of potentially pathogenic bacteria (i.e. , gram negative species) and a decrease in autoch- thonous familiae. Here we summarize the available literature on the risk of gut dysbiosis in liver cirrhosis and its clinical consequences. We therefore described the features of the complex interaction between gut microbiota and cirrhotic host, the so called “gut-liver axis”, with a particular attention to the acquired risk of bacterial translocation, systemic inflammation and the relationship with systemic infections in the cirrhotic pa- tient. Such knowledge might help to develop novel and innovative strategies for the prevention and therapy of gut dysbiosis and its complication in liver cirrhosis
The predatory bacterium Bdellovibrio bacteriovorus is mucosa associated in healthy pediatrics patients and absent under inflammatory conditions.
No full textDominant Genotypes in Mucosa-Associated Escherichia Coli Strains from Pediatric Patients with Inflammatory Bowel Disease
No full textEscherichia coli (E. coli), a predominant facultative anaerobe of the human colonic flora, has been thought to participate in the pathogenesis of inflammatory bowel disease (IBD). Increased numbers of mucosa-associated E. coli have been observed in adult IBD patients; furthermore, some E. coli strains from Crohn's disease (CD) patients have been shown to adhere to intestinal epithelial cells and invade them, as well as to replicate extensively into macrophages. It has also been suggested that some E. coli genotypes are more likely than others to be associated with CD in adults. There are no studies on the molecular characterization of mucosa-associated bacteria in children with pediatric IBD. Aims: children with IBD were investigated in order to characterize mucosa-associated E. coli strains and to assess if a particular subset of E. coli strains could be associated with IBD in these subjects. Methods and subjects: we analyzed genomic profile, phylogenetic grouping, virulence-gene carriage, different biochemical and enzymatic properties, and adhesive/invasive abilities of 60 E. coli strains isolated from mucosal biopsies of pediatric patients affected by CD (12 cases), ulcerative colitis (UC) (7 cases), and from those of 19 children with functional intestinal disorders who served as controls. Median (and ranges) age (years) was 14.0 (12-17), 10.0 (8-13), 12.7 84-16), respectively. Patients underwent ileo-colonoscopy as a step of their diagnostic approach after parental written consensus. The study was approved by the ethical committee of the Faculty. Results: in E. coli strains deriving from IBD patients and from controls no noteworthy differences were found in the distribution of phylogroups, in the adhesive properties as well as in the occurrence of virulence-related genes . However, the genetic profile examination revealed two large clusters of genetically linked E. coli strains from IBD patients: in the first cluster were grouped 92% of E. coli strains isolated from CD patients, distributed between two sub-clusters; in the second cluster 78% of strains isolated from UC and 77% from controls, distributed between two sub-clusters, respectively. Conclusions: in children with IBD, whereas phenotypic characterization failed to identify peculiar pathogenetic strains, genomic analysis was able to define a close genetic relatedness among E. coli strains associated with CD and UC gut mucosa
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
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