1,720,964 research outputs found
Cytogenetic aspects of cell proliferation in atherosclerotic plaques
No full textFluorescence in situ hybridization (FISH) using chromosome specific alpha-satellite DNA probes for chromosome 7, was performed on paraffin-embedded sections of 21 cases of human "unstable" atherosclerotic plaques, in order to determine whether trisomy 7, found by some Authors with conventional cytogenetics, is a biological characteristic of the atherosclerotic plaque. In 15 cases (71%) the FISH method showed smooth muscle cells with three or more spots. In particular the trisomy 7 was the most significant and constant result. The presence of an extra chromosome 7 is strictly correlated with an overexpression of the gene for chain A of the platelet-derived growth factor (PDGF), which was mapped at pter-7q22 region. Therefore trisomy 7 seems to correspond to an increase in PDGF synthesis and consequently to an increase in proliferative activity of smooth muscle cells
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
The role of different biomarkers (DNA, PCNA, apoptosis and karyotype) in prognostic evaluation of superficial transitional cell bladder carcinoma.
No full textBACKGROUND:
In order to clarify the variable behaviour of transitional cell bladder carcinomas (TCBC) with same clinico-pathologic pattern, we investigated the prognostic significance of various biomarkers (PCNA, DNA, apoptosis, karyotype).
MATERIALS AND METHODS:
We studied 177 superficial TCBC (stage T1) undergoing transurethral resection (TUR). Analysis of biological indicators was performed on serial paraffin sections: DNA by static cytometry, karyotype by fluorescence in situ hybridisation (FISH), PCNA and apoptosis by immunohistochemistry.
RESULTS:
The most salient results are represented by prevalence of diploidy (56%), a mean PCNA labeling index (PCNA-LI) of 8.2%, nonrandom trisomies and tetrasomies of chromosome 7, and a high presence of apoptosis (in 72% of cases). These data were not related to histological grading. Multivariate analysis showed that only PCNA-LI is a an independent prognostic marker for patient survival (p = 0.01). Besides, we observed a worse prognosis in the presence of both very high PCNA indices and low or absent apoptosis.
CONCLUSIONS:
The results of this study suggest that tumor prognostic potential in TCBC should be evaluated on the basis of the association between PCNA cell kinetics and cell apoptosis information
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
Expression of apoptosis and proliferating cell nuclear antigen (PCNA) in the cardiac conduction system in crib death (SIDS)
No full textAim of this study is to determine the expression of apoptosis and Proliferating Cell Nuclear Antigen (PCNA) in the cardiac conduction system in crib death and explained death (ED) cases. Postnatal morphogenesis of the conducting tissue is an important part of its normal development. In the atrio-ventricular node (AVN) and His bundle (HB) it consists of degeneration, cell death and replacing in an orderly programmed way. However, its nature and its relation to crib death is not yet fully explained. Apoptosis and PCNA were investigated in 8 heart conduction systems of infants dying of crib death and in 3 conduction systems of infants dying of ED as controls. The cardiac conduction system was removed in two blocks: the first included the sino-atrial node (SAN) and the crista terminalis, the second contained the atrio-ventricular node (AVN), His bundle (HB), bifurcation, and bundle branches. In the conduction systems as well as in the common myocardium the PCNA Labeling Index (PCNA-LI) was found to be negative in all cases. The apoptotic indices (AI) in SIDS and in ED were found to have no statistically significant differences (p>0.05). The SAN, in both groups, showed an AI similar to the one detected in common myocardium. In almost all cases, TUNEL labeling was detected in peripheral region of the AVN, close to the atrial myocardium. The AI was higher in the AVN, HB and the initial tract of bundle branches than in the common myocardium (p<0.05; Student's t test)
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
Detection of trisomy 7 with fluorescence in situ hybridization and its correlation with DNA content and proliferating cell nuclear antigen-positivity in prostate cancer.
No full textThe authors applied fluorescence in situ hybridization (FISH), using specific DNA probes for chromosome 7, to routine paraffin-embedded tissue sections obtained from 35 radical-prostatectomy specimens. Proliferative activity was also evaluated using static cytometry to assess DNA content and immunohistochemistry for proliferating cell nuclear antigen (PCNA) positivity. These results were correlated with each other and with the morphologic parameters. The presence of three or more of chromosome 7 was observed in 71% of the cases, as was a high S phase, with a triploid prevalent DNA content and a PCNA index above mean value in 66% of the cases. No correlation was detected between these findings and histologic grade; conversely, there was a significant correlation with stage (chi-square = 5.33; p = 0.021). From these results, the authors maintain that the presence of an extra chromosome 7-correlated in most cases with an increase in cell kinetics and an advanced stage-may be an additional prognostic marker of aggressive behavior
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