1,720,965 research outputs found
Characterization of biofilms in drug-sensitive and drug-resistant strains of Candida albicans
No full textIn this study, we investigated the biofilm formation in strains of Candida albicans susceptible (CO23) or resistant to fluconazole (CO23RFLC) or micafungin (CO23RFK). The effect of drug resistance on biofilm formation was investigated through the cell surface hydrophobicity and the mannan content. Moreover, biofilm formation was evaluated after 24, 48 and 72 hours with crystal violet assay, dry weight, as well as scanning electron microscopy. Our results showed an increase in hydrophobicity, polysaccharides content, metabolic activity and dry weight. Observation of sensitive and resistant strains confirmed the differences in cell morphology. Finally, the expression of genes involved in biofilm formation, such as HWP1 and EFG1, evaluated with relative real-time RT-PCR. Resistant strains proved to up- regulate the expression of HWP1. These results demonstrated the existence of important differences between drug-susceptible and drug-resistant strains biofilm of C. albicans
Spermine enzymatic oxidation products induce mitochondrial modifications on human cancer cells overexpressing p-glycoprotein, at 37 and 42 °c.
No full textMeccanismo di azione e proprietà terapeutiche dell’olio essenziale di Melaleuca alternifolia su ceppi farmacosensibili e farmacoresistenti di Candida albicans
No full textLe malattie infettive sono causate da microrganismi che interagiscono in modo
complesso con l’ospite. La scoperta degli antibiotici e il loro impiego sono risultati molto
efficaci nel trattamento delle infezioni batteriche e fungine, ma il loro uso indiscriminato ha
purtroppo causato lo sviluppo di ceppi patogeni resistenti.
Infatti, negli ultimi anni le terapie anticancro (chemio e radio-terapia) e l’AIDS hanno
pesantemente contribuito all’aggravarsi dell’immunocompromissione dei pazienti che
vivono a lungo in questo stato. Difatti, in questi pazienti sono ricorrenti le infezioni fungine
localizzate e sistemiche e per prevenire l’evolversi di tali patologie viene incrementato l’uso
di farmaci antimicotici anche per la profilassi. Purtroppo, con l’uso eccessivo di questi
farmaci si è registrato anche un significativo incremento dei fenomeni di resistenza agli
antimicotici (1). Storicamente la resistenza clinica è stata definita come persistenza o
progressione di un’infezione nonostante la terapia antimicrobica appropriata. Una
successiva risposta clinica alla terapia antimicrobica, tipicamente, non solo dipende dalla
suscettibilità dell’organismo patogeno, ma molto dal suo sistema immunitario, dalla
penetrazione e distribuzione del farmaco e da complicanze nel paziente. La resistenza in
vitro di un isolato può essere descritta come primaria o secondaria. Un organismo che
risulta resistente ad un farmaco prima dell’esposizione presenta resistenza primaria
intrinseca. La resistenza secondaria si sviluppa in risposta all’esposizione ad agenti
antimicotici (2). Una correlazione di suscettibilità rivelata in vitro con quella riscontrata in
vivo, è stata osservata per infezioni mucosali di Candida in pazienti HIV positivi (3).
Candida albicans (C. albicans) è un fungo diploide che vive solitamente come
colonizzatore innocuo e commensale del tratto gastrointestinale e genitale dell’uomo,
oppure come patogeno opportunista in presenza di uno o più fattori predisponenti (4).
La sua patogenicità è dovuta alla capacità di invadere tessuti e organi e di dar luogo a
difficili, talvolta intrattabili, infezioni superficiali.
Anche l’abilità di C. albicans nel formare biofilm sulle superfici (cellule endoteliali e
cateteri) è considerata responsabile della “resistenza clinica”. È noto infatti, che la
formazione dei biofilms può conferire protezione al microrganismo all’interno degli strati,
portando al fallimento della terapia antimicotica (5)
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
Meccanismo di azione e proprietà terapeutiche degli oli essenziali su ceppi di Candida albicans farmacosensibili e farmacoresistenti
No full textVariations 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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