1,720,972 research outputs found
MECCANISMO TRASFORMANTE DEI VIRUS ONCOGENI HPV IN CELLULE EPITELIALI UMANE DELLA CERVICE UTERINA
No full textThe aims of this study are: (i) to set up a culture protocol to derive pathological and
normal keratinocytes from small human cervical intraneoplasia (CIN) biopsies and
normal uterine cervix (NUC) tissues; (ii) to investigate the expression prfile induced by
transforming mechanisms due to human papillomavirus (HPV) in CIN keratinocytes
clones from different CIN grades, CIN1-3/CIS, using the microarray technique.
In this study a new approach to establishing CIN and NUC keratinocyte cultures from
small tissue fragments was developed. CIN specimens and corresponding normal
tissues, which were used as controls, were digested with collagenase. Tissue-derived
fibroblasts and keratinocytes were co-cultured in calcium serum medium conditions.
Primary co-cultures were subsequently sub-cultured. Single keratinocyte clones from
primary co-cultures were expanded using a culture medium which was optimized in our
laboratory. Primary clones from CIN and normal tissues, as well as expanded clones,
were tested by immunofluorescence for epithelial and cervical markers such as 5-, 14-,
17- and 19-keratins, and p63. Our results indicate that primary CIN, as well as normal
keratinocyte clones, can be obtained in a co-culture system with live human fibroblasts
in calcium and serum medium conditions. The clone number varied depending on the
grade of CIN lesions from which clones originated. CIN and normal keratinocytes from
single clones, when cultured with our new medium, grew at a high rate with uniform
morphology.
The second objective of our study was to identify genes that are related to progression
and transformation inducted by HPV in CIN lesions using the microarray technique.
One clone of CIN1; two clones of CIN2 and corresponding normal clones; one clone of
CIN3 and corresponding normal; one clone of in situ cervical cancer (CIS), were
investigated with microarray technique for analysis of differential gene expression
profile. The expression of ~ 41,000 genes were compared and 598 genes resulted
differentially expressed between CIN and NUC. Among 598 genes, 152 genes were upregulated
and 262 were down-regulated. We selected some genes with a greater than 2 fold difference between CIN and NUC for validation of microarray results with RTqPCR.
Some genes were selected as possible candidates involved in progression from
CIN1 to CIN3/CIS. Among up-regulated we identified PFKFB3, FOXD2, HOXB3,
HOXB4, HOXA3, HOXA4, HOXA5, EMX2, WNT4 and among down-regulated
APOBEC3B, APOBEC3F, PTPN3, CLDN11, S1PR5, IL1B. These results will need to
be validated in a larger series of dysplasia to identify whether our selected genes could
play a role in cervical tumorigenesis.
In conclusion, our study reports, for the first time, a co-culture system of keratinocytes
from minute CIN and normal cervix biopsies and offers a potential of developing newer
diagnostic markers and therapeutic targets for the prevention and treatment of the
cervical carcinoma
LINEE CELLULARI EPITELIALI DERIVATE DA CERVICE UTERINA SANA E PATOLOGICA PER LO STUDIO DEL MECCANISMO TRASFORMANTE E DI PROGRESSIONE NEOPLASTICA DEI VIRUS HPV.
No full text
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
ANALISI DI PCR QUALITATIVA E QUANTITATIVA DEL DNA DEL VIRUS ONCOGENO SV40 IN CAMPIONI DI SANGUE DI DONATORI DI CASALE MONFERRATO, CITTÀ CONTAMINATA DALL’AMIANTO
No full textL’amianto è considerato l’agente tumorale responsabile dell’insorgenza del mesotelioma maligno della pleura (MM). MM è un tumore molto aggressivo, attualmente privo di cura, la cui incidenza sta aumentando in molti Paesi, soprattutto nelle coorti di lavoratori ex esposti all’amianto. La predisposizione genetica e l’infezione da virus oncogeno SV40 sono considerati come altri fattori coinvolti nell’insorgenza e progressione del mesotelioma maligno della pleura,. SV40 è un potente virus oncogeno a DNA, accidentalmente somministrato alla popolazione umana su scala planetaria negli anni 1955-63 con i primi vaccini allestiti contro la poliomielite, sia di Salk che di Sabin. SV40 infetta naturalmente il macaco asiatico ed era presente nelle colture primarie di cellule di rene di scimmia impiegate per produrre i primi vaccini antipolio. Molti dati sperimentali indicano che SV40 è anche un virus umano. La trasmissione orizzontale dell’infezione sembra avvenire con diverse modalità, come per via sessuale, ematica, oro-fecale e respiratoria e con le urine contaminate. In condizioni sperimentali SV40 trasforma differenti linee cellulari animali e umane, mentre inoculato per diverse vie in animali da laboratorio induce specifici tumori, come tumori cerebrali, mesoteliomi, osteosarcomi e linfomi. Il potenziale trasformante ed oncogeno di SV40 risiede nella sua principale oncoproteina, l’antigene T grande (agT). Sequenze del DNA di SV40 e l’espressione dell’agT sono state evidenziate in specifici tumori umani, dello stesso tipo indotti negli animali. Ad esempio sequenze di SV40 e l’espressione dell’agT sono state mostrate in circa il 50% dei mesoteliomi maligni della pleura.
Scopo di questo studio è stato di verificare la presenza di sequenze del DNA di SV40 in cellule del sangue periferico di donatori sani provenienti dal Centro Trasfusionale di Casale Monferrato. In questa cittadina industriale, pesantemente contaminata dall’amianto, l’incidenza del mesotelioma maligno della pleura nella popolazione è di dieci volte superiore rispetto ad aree non contaminate con l’amianto. Il DNA estratto da buffy coats, raccolti presso il locale Centro Trasfusionale, è stato analizzato con saggi di PCR qualitativa e quantitativa.
La presenza di sequenze codificanti per la regione ammino-terminale dell’agT di SV40 è stata indagata mediante l’analisi di nested PCR. Tali sequenze specifiche sono state evidenziate in 24/148 (16%) campioni. In seguito, i campioni positivi per l’agT sono stati analizzati per le sequenze della regione di regolazione di SV40. L’analisi di nested PCR ha mostrato che 17/24 campioni sono positivi anche per queste sequenze virali. E’ interessante notare che la regione di regolazione del DNA di SV40 contiene sequenze specifiche che consentono di distinguere tra loro i tre principali virus polioma (SV40, BK e JC) e i diversi ceppi di SV40. Nove amplificati della regione di regolazione di SV40, di campioni diversi di buffy coats, sono stati sottoposti ad analisi di sequenziamento del DNA. La sequenza nucleotidica indica che i nove amplificati appartengono al ceppo selvatico 776.
Allo scopo di quantificare nei campioni di sangue SV40-positivi la carica del DNA virale sono state eseguiti saggi di Real-Time PCR su 22 DNA estratti da buffy coats. Questa analisi ha confermato che i 22 campioni erano SV40-positivi per le sequenze dell’agT, con un numero di copie di DNA virale comprese tra 10 e 104 per 100,000 cellule o genomi equivalenti.
La nostra ricerca indica che la prevalenza di SV40 in campioni di buffy coats di donatori sani di Casale Monferrato, è simile a quella riscontrata in altri donatori di sangue di aree non contaminate dall’amianto. I nostri risultati indicano che l’amianto presente nell’ambiente di Casal Monferrato non facilita la diffusione dell’infezione di SV40, almeno tra i donatori sani analizzati. Tuttavia, la presenza di sequenze di SV40 nei donatori suggerisce l’ipotesi che amianto e virus oncogeno agiscono come co-fattori nell’insorgenza dell’MM. Infatti, il minerale amianto oltre ad essere agente tumorale è anche un potente immunodeppressivo che potrebbe favorire la diffusione dell’infezione di SV40 nei tessuti dell’ospite. In condizioni peculiari dell’individuo/paziente si potrebbe quindi innescare l’azione combinata tra amianto e virus oncogeno durante il meccanismo multifase della tumorigenesi che nei lavoratori ex esposti all’amianto può durare decenni.
I nostri risultati relativi alla presenza di sequenze di SV40 nei donatori di sangue indicano che il virus oncogeno SV40 circola nella popolazione umana. La sua prevalenza è di circa il 15%-20%, mentre il numero di copie di DNA virale nei campioni positivi risulta essere di bassa entità
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