1,720,957 research outputs found
Expression and activity of vascular endothelial growth factor and metalloproteinases in alveolar and embryonal rhabdomyosarcoma cell lines.
No full textRhabdomyosarcoma (RMS) is a malignant tumour of skeletal muscle origin which includes two major histological subtypes: alveolar rhabdomyosarcoma (ARMS), the more aggressive, and embryonal rhabdomyosarcoma (ERMS). In order to establish whether the higher metastatic potential of ARMS cells may depend on differential expression of specific matrix metalloproteinases (MMPs) and angiogenesis-related factors, we studied the expression of MMP-2, MT1-MMP, TIMP-2, VEGF and VEGF receptors in four ARMS (RH30, RH4, RH18, RH28), three ERMS (RD, RH36, SMS-CTR) and one undifferentiated sarcoma cell line (A204). Semi-quantitative analysis of MMP-2 revealed high levels of expression in 3 out of 4 ARMS cell lines whereas, among ERMS, only RH36 showed comparable levels of the protease. TIMP-2 and MT1-MMP showed no significant differences among cell lines. in vitro invasiveness was also evaluated. The MMP-2-overexpressing RH30 cells were more invasive than RD cells, which expressed low levels of MMP-2. Exogenous expression of the ARMS specific PAX3-FKHR chimeric protein in RD cells increased MMP-2 activity and invasiveness. Of the three main VEGF isoforms only VEGF165 and VEGF121 were detected in RMS lines: ARMS expressed both isoforms, whereas the ERMS cell line SMS-CTR and the undifferentiated sarcoma cell line A204 showed the VEGF121 isoform only. All RMS cell lines expressed VEGFR-1 at mRNA as well as at protein level. The VEGFR-2, on the contrary, was undetectable with the sole exception of the RH28 cell line. Overall, our data suggest that a high level of MMP-2 protein and VEGF/VEGFR expression may contribute to the metastatic phenotype of ARMS cells and that exogenously induced PAX3-FKHR expression increases MMP-2 secretion and invasive capability of RMS cells
Characterization of HSFY, a novel AZFb gene on the Y chromosome with a possible role in human spermatogenesis
No full textHSFY (heat shock transcription factor, Y chromosome) has been mapped in the AZFb region of the Y chromosome, whose deletion results in severe male infertility. HSFY belongs to the heat shock factor family that has been shown to be implicated in spermatogenesis both in animals and humans. We report the characterization of the genomic structure, the number of copies on the Y chromosome and the expression of the gene. By comparison of data obtained from expression analysis and from GenBank cDNA sequences, seven exons were identified. Alternative splicing generates three different transcripts and proteins, each containing an HSF domain typical of HSF proteins. Two identical and functional full-length copies of HSFY map in palindrome P4 of AZFb, whereas four similar sequences mapping in two clusters in palindrome P1 of AZFc and P3 seem to represent pseudogenes. Sequences similar to few HSFY exons are also located in the short arm of chromosomes Y, X and 22. Expression analysis revealed that the three HSFY transcripts are differentially expressed, transcript 1 being present in many tissues including testis and ejaculated sperm, and transcripts 2 and 3 being testis-specific. These data suggest that HSFY could have an important role in human spermatogenesis
A novel gene (PD1) with a potenzial role on rat spermatogenesis
No full textSettore ISI: Endocrinology and metabolism; I.F. 1.59
Zebrafish spata2 is expressed at early developmental stages
No full textSpata2 (spermatogenesis-associated protein 2) was originally described as a novel gene involved in the spermatogenic process. In this study, we cloned a potential zebrafish spata2 orthologue. The consensus open reading frame (1650 bp) encodes a polypeptide of 550 amino acids which shares 37% identity with the human SPATA2. Bioinformatic analysis reveals a small pattern PW [KR] KE [YF][RK] which seems to be of particular interest in the light of its strong conservation between SPATA2 and the recently discovered TAMO protein of D. melanogaster. RTPCR analysis in adult zebrafish tissues revealed that spata2 mRNA has a broad distribution. Whole-mount in situ hybridization demonstrated that spata2 transcripts are maternally derived and becomes strongly localized in the central nervous system at early developmental stages. From 5 dpf, spata2 expression becomes detectable in the gut and pronephric duct epithelium, suggesting a wide tissue function during vertebrate development
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
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