1,720,963 research outputs found
Caratterizzazione di cellule staminali tumorali ottenute da linee cellulari di carcinoma della laringe e di carcinoma della vescica
No full textCaratterizzazione di cellule staminali tumorali ottenute da linee cellulari di carcinoma della laringe e di carcinoma della vescica
Secondo la teoria delle cellule staminali tumorali, lo sviluppo del tumore sarebbe sostenuto dalla presenza di una distinta sottopopolazione di cellule tumorali, denominate cancer stem cells (CSCs), dotate della capacità di autorigenerarsi e di una spiccata resistenza agli agenti chemioterapici.
Nel presente studio, è stato messo a punto un protocollo di crescita volto all’arricchimento in CSCs, mediante formazione di sfere, delle linee cellulari Hep-2 (carcinoma della laringe), T24 (carcinoma della vescica), MG63 (osteosarcoma), CaCo-2 (carcinoma del colon-retto) e A549 (carcinoma polmonare). Successivamente è stata effettuata un caratterizzazione molecolare e fenotipica delle popolazioni arricchite in CSCs, mediante rispettivamente l’analisi di espressione di markers di staminalità e la valutazione in vivo del potenziale tumorigenico. Inoltre, a carico delle CSCs e delle cellule di controllo, sono stati analizzati i livelli dell’enzima nicotinamide N-metiltrasferasi (NNMT).
L’analisi immunocitochimica e mediante Real-Time PCR hanno evidenziato elevati livelli di espressione dei markers di staminalità nelle popolazioni cellulari arricchite in CSCs rispetto ai controlli. In seguito all’inoculo in topi atimici delle cellule relative alla linea Hep-2, la popolazione arricchita in CSCs dava luogo a masse tumorali di dimensioni maggiori rispetto a quelle originatesi dalle cellule di controllo, evidenza che suggerisce la spiccata capacità da parte delle CSCs di indurre la formazione in vivo di tumori. Le analisi condotte a carico dell’NNMT mostrano un’overespressione dell’enzima nelle popolazioni arricchite in CSCs rispetto ai controlli.
In considerazione dell’importante ruolo svolto dalle CSCs nello sviluppo di recidive e nella diffusione metastatica, i risultati riportati in questo lavoro potrebbero contribuire allo sviluppo di nuove strategie terapeutiche per il trattamento del cancro e suggeriscono il significativo coinvolgimento dell’NNMT nel metabolismo della cellula neoplastica.
Dottorando:
Dott. Rachela Giuliante
Tutor:
Prof. Monica Emanuelli
Coordinatore:
Prof. Fiorenzo Cont
Nicotinamide N-methyltransferase in Non-small Cell Lung Cancer: Promising Results for Targeted Anti-cancer Therapy.
No full textLung cancer, predominantly non-small cell lung cancer (NSCLC), is currently the most common cause of malignancy-related death in the world. Despite advances in both detection and treatment, its incidence rate is still increasing. Therefore, effective strategies for early detection as well as molecular therapeutic targets are urgently needed. We focused on the enzyme nicotinamide N-methyltransferase (NNMT). NNMT expression levels were investigated in tumor, tumor-adjacent, and surrounding tissue samples of 25 patients with NSCLC by Real-Time PCR, Western blot analysis, and catalytic activity assay. NNMT enzyme activity in NSCLC was then correlated with clinicopathological characteristics. Results obtained showed NNMT upregulation (mRNA and protein) in tumor compared with both tumor-adjacent and surrounding tissue. Moreover, NSCLC displayed significantly higher activity levels than those determined in both tumor-adjacent and surrounding tissue. Interestingly, both tumor-adjacent and surrounding tissue samples of unfavorable cases (N+) seem to display higher activity levels than those of favorable NSCLCs (N0). The present work shows a marked increase of NNMT enzyme activity in NSCLC and suggests that normal-looking tissue of unfavorable cases seems to change toward cancer. Further studies may establish whether NNMT could represent a target for an effective anti-cancer therapy
Enhanced expression of nicotinamide N-methyltransferase in non-small cell lung cancer: potential for the development of a targeted anticancer therapy.
No full text
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
- …
