1,720,991 research outputs found
CANDIDIASIS, CHLAMYDIA INFECTION, BACTERIAL VAGINOSIS: A BIOINFORMATICS APPROACH FOR PATHOLOGICAL VAGINAL MICROBIOME CHARACTERIZATION
No full textHuman milk microbiota: correlations with fatty acids composition and diet in the first six months after delivery
No full textMICROBIOTA VAGINALE IN CORSO DI INFEZIONI DEL TRATTO GENITALE
No full textIntroduzione. Nel tratto genitale femminile coesistono diverse specie batteriche in un equilibrio dinamico, che può variare in risposta a molteplici fattori quali età, gravidanza, uso di farmaci, infezioni o patologie croniche.
Le infezioni genitali e le disbiosi colpiscono ogni anno oltre un miliardo di donne, con un significativo impatto sulla qualità di vita e sulla salute riproduttiva. La vaginosi batterica (BV) è la disbiosi più comune, caratterizzata da una riduzione delle specie normalmente dominanti (Lactobacillus), che vengono sostituite da una comunità polimicrobica anaerobia. Tra le infezioni urogenitali più comuni si riscontrano la candidiasi vulvovaginale e le infezioni da Chlamydia trachomatis (CT), che rappresentano la più comune infezione batterica a trasmissione sessuale nel mondo. L’obiettivo di tale lavoro è stato quello di analizzare la composizione del microbiota vaginale in donne con diverse condizioni fisiologiche e patologiche del tratto genitale.
Materiali e metodi. Sono state incluse nello studio 21 donne sane, 20 donne con BV, 18 con candidiasi vaginale e 21 con infezione da CT. Per lo studio del microbiota, è stato estratto il DNA genomico a partire da un tampone vaginale e successivamente sono state amplificate e sequenziate le regioni V3-V4 del gene 16S rRNA batterico (MiSeq Illumina).
La classificazione tassonomica è stata condotta fino al livello di genere per tutti i microrganismi, ad eccezione dei lattobacilli, che sono stati identificati fino a livello di specie, per mezzo di un database specifico di riferimento. Per valutare la variabilità della composizione del microbiota inter- e intra-gruppo, sono state eseguite valutazioni di α- e β-diversità, rispettivamente.
Risultati. Le donne sane erano caratterizzate da un basso indice di α-diversità, con un microbiota dominato da diverse specie di lattobacilli (Firmicutes). Al contrario, le donne con BV mostravano il più alto grado di diversità microbica, con un microbiota depleto di lattobacilli e ricco di molteplici specie batteriche differenti.
Nelle donne con infezione da CT e candidiasi, la composizione del microbiota è apparsa simile, più vicina a quella delle donne sane rispetto, che a quelle con BV. Il microbiota vaginale di questi ultimi due gruppi, infatti, era sempre dominato da Firmicutes, ma la loro abbondanza relativa diminuiva progressivamente passando dalle donne sane a quelle con clamidia, candidiasi e BV.
Conclusioni. I nostri risultati hanno confermato l’elevato grado di diversità tra il microbiota vaginale di donne sane e di donne con BV, e hanno dimostrato come la candidiasi e l’infezione da CT rappresentino una condizione intermedia fra questi due estremi
Anti-chlamydial activity of vaginal fluids: new evidence from an in vitro model
Full text linkIntroduction: We assessed the in vitro anti-chlamydial activity of fresh vaginal secretions, deciphering the microbial and metabolic components able to counteract Chlamydia trachomatis viability. Methods: Forty vaginal samples were collected from a group of reproductive-aged women and their anti-chlamydial activity was evaluated by inhibition experiments. Each sample underwent 16S rRNA metabarcoding sequencing to determine the bacterial composition, as well as 1H-NMR spectroscopy to detect and quantify the presence of vaginal metabolites. Results: Samples characterized by a high anti-chlamydial activity were enriched in Lactobacillus, especially Lactobacillus crispatus and Lactobacillus iners, while not-active samples exhibited a significant reduction of lactobacilli, along with higher relative abundances of Streptococcus and Olegusella. Lactobacillus gasseri showed an opposite behavior compared to L. crispatus, being more prevalent in not-active vaginal samples. Higher concentrations of several amino acids (i.e., isoleucine, leucine, and aspartate; positively correlated to the abundance of L. crispatus and L. jensenii) lactate, and 4-aminobutyrate were the most significant metabolic fingerprints of highly active samples. Acetate and formate concentrations, on the other hand, were related to the abundances of a group of anaerobic opportunistic bacteria (including Prevotella, Dialister, Olegusella, Peptostreptococcus, Peptoniphilus, Finegoldia and Anaerococcus). Finally, glucose, correlated to Streptococcus, Lachnospira and Alloscardovia genera, emerged as a key molecule of the vaginal environment: indeed, the anti-chlamydial effect of vaginal fluids decreased as glucose concentrations increased. Discussion: These findings could pave the way for novel strategies in the prevention and treatment of chlamydial urogenital infections, such as lactobacilli probiotic formulations or lactobacilli-derived postbiotics
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
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