1,720,964 research outputs found
Kirsten Ras* oncogene: Significance of its discovery in human cancer research
No full textThe KRAS/ K-RAS oncogene is crucially involved in human cancer. The term "oncogene" - i.e., a gene able to transform a normal cell into a tumor cell - was introduced in 1969, but the word was not used in the human carcinogenesis literature until much later. Transforming Kras and Hras oncogenes from the Kirsten and Harvey sarcoma viruses were not identified until the early 1980s due to the complicated structures of the viral genomes. Orthologs of these viral oncogenes were then found in transforming DNA fragments in human cancers in the form of mutated versions of the HRAS and KRAS proto-oncogenes. Thus, RAS genes were the first human oncogenes to be identified. Subsequent studies showed that mutated KRAS acted as an in vivo oncogenic driver, as indicated by studies of anti-EGFR therapy for metastatic colorectal cancers. This review addresses the historical background and experimental studies that led to the discovery of Kirsten Ras as an oncogene, the role of mutated KRAS in human carcinogenesis, and recent therapeutic studies of cancer cells with KRAS mutations
FUCA1 is induced by wild-type p53 and expressed at different levels in thyroid cancers depending on p53 status
No full textFucose residues of cell surface glycans, which play
important roles in growth, invasion and metastasis, are added
by fucosyltransferases (FUTs) and removed by α-L-fucosidases
(FUCAs). By the differential display method, we isolated a
3' non-coding region of α-L-fucosidase-1 (FUCA1) (a gene
coding for the lysosomal fucosidase-1 enzyme) as a wild-type
p53-inducible gene: 18S and 20S FUCA1 mRNA species were
induced in Saos-2 cells transfected with a temperature-sensitive
p53 mutant at the permissive temperature. By microarray
analyses of thyroid cancer biopsy samples, FUCA1 RNA
expression levels were found to be lower in anaplastic thyroid
cancer samples (ATCs), while they were higher in papillary
thyroid cancer samples (PTCs) and in normal thyroid tissues.
Since most ATCs were reported to carry the mutated form
of p53, while PTCs carry mostly the wild-type form of p53,
it is likely that FUCA1 expression levels are regulated, at
least in part, by the p53 status in thyroid cancers. In order to
better understand the role played by FUCA genes in thyroid
tumorigenesis, we examined the clonogenic potential in vitro
of thyroid cell lines transfected with either FUCA1 or FUCA2
(the latter gene coding for a secreted, non-lysosomal enzyme).
We found that α-L-fucosidases did not suppress grossly cell
growth. Contrary to what we observed with the expression of
FUCA1, the FUT8 expression levels were found high in ATCsbut lower in PTCs and normal thyroid tissues. Taken together,
these results suggest the possibility that the higher fucose
levels on cell surface glycans of aggressive ATCs, compared to
those of less aggressive PTCs, may be at least in part responsible
for the more aggressive and metastatic phenotype of
ATCs compared to PTCs, as the expression levels of FUCA1
and FUT8 were inversely related in these two types of cancers.Fucose residues of cell surface glycans, which play important roles in growth, invasion and metastasis, are added by fucosyltransferases (FUTs) and removed by α-L-fucosidases (FUCAs). By the differential display method, we isolated a 3' non-coding region of α-L-fucosidase-1 (FUCA1) (a gene coding for the lysosomal fucosidase-1 enzyme) as a wild-type p53-inducible gene: 18S and 20S FUCA1 mRNA species were induced in Saos-2 cells transfected with a temperature-sensitive p53 mutant at the permissive temperature. By microarray analyses of thyroid cancer biopsy samples, FUCA1 RNA expression levels were found to be lower in anaplastic thyroid cancer samples (ATCs), while they were higher in papillary thyroid cancer samples (PTCs) and in normal thyroid tissues. Since most ATCs were reported to carry the mutated form of p53, while PTCs carry mostly the wild-type form of p53, it is likely that FUCA1 expression levels are regulated, at least in part, by the p53 status in thyroid cancers. In order to better understand the role played by FUCA genes in thyroid tumorigenesis, we examined the clonogenic potential in vitro of thyroid cell lines transfected with either FUCA1 or FUCA2 (the latter gene coding for a secreted, non-lysosomal enzyme). We found that α-L-fucosidases did not suppress grossly cell growth. Contrary to what we observed with the expression of FUCA1, the FUT8 expression levels were found high in ATCs but lower in PTCs and normal thyroid tissues. Taken together, these results suggest the possibility that the higher fucose levels on cell surface glycans of aggressive ATCs, compared to those of less aggressive PTCs, may be at least in part responsible for the more aggressive and metastatic phenotype of ATCs compared to PTCs, as the expression levels of FUCA1 and FUT8 were inversely related in these two types of cancers
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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