1,721,080 research outputs found
EP-1606: Calculating ion-induced cell death and chromosome damage by the BIANCA biophysical model
No full textMet protein and hepatocyte grwth factor (HGF) in papillary carcinoma of the thyroid: evidence for a pathogenetic role in tumorigenesis.
No full textIn the last 10 years, evidence has accumulated that overexpression of Met protein is a distinguishing feature of almost every case of well-differentiated papillary carcinoma. Increased expression of the protein is probably due to enhanced transcription of the MET gene and/or to post-transcriptional mechanisms. So far, alterations of the MET gene have not been recognized, but evidence has been provided that activated RAS and RET can cause accumulation of MET RNA. Thus, the possibility exists that dysregulation of MET is the final result of different molecular pathways capable of inducing thyroid cell transformation; RET rearrangements might account for some of the cases, but the demonstration that the majority of papillary carcinomas do not have recognized alterations of the RET gene strongly suggests that MET gene dysregulation can also be achieved through other molecular pathways. Dysregulation of MET causes marked accumulation of Met protein in tumour cells that is promptly detected by immunohistochemistry. Thus, overexpression of Met protein might represent an immunohistochemical marker of papillary carcinoma, potentially helpful in problematic cases, but caution is required; moderate expression of Met protein is observed in non-neoplastic thyroid diseases, such as Graves' and Hashimoto's thyroiditis, and reagents active on paraffin sections may have a low affinity and/or low specificity for Met protein, leading to artifactual staining. Met protein-positive papillary carcinoma cells may produce hepatocyte growth factor (HGF) and may activate HGF through the urokinase-type plasminogen activator (uPA) bound to urokinase-type plasminogen activator receptor (uPA-R). Thus, papillary carcinoma cells possess the molecular machinery necessary for a productive HGF/Met interaction. In vitro studies have demonstrated that HGF enhances the motility and invasiveness of tumour cells and induces the synthesis and release of chemokines active in the recruitment of dendritic cells. These observations provide a rational basis for the understanding of two distinguishing features of papillary carcinoma. First, the tumour is often characterized by early metastatic spread to regional lymph nodes and by multifocal involvement of the gland, which suggests highly invasive behaviour. Second, a prominent peritumoural inflammatory reaction is often observed, which suggests cross-talk between tumour cells and the immune system
CONTRACTILE RESPONSE OF PERITUBULAR MYOID CELLS TO PROSTAGLANDIN F2alfa
No full textProstaglandin (PG) F2alpha, a well known agonist of smooth muscle, is produced in the male gonad. We have investigated whether PG F2alpha stimulates seminiferous tubule contractility through direct action on peritubular myoid cells. Myoid cells from prepubertal rats were highly purified through Percoll density gradient and cultured in vitro. Stimulation with PG F2alpha was observed to induce: (i) rapid and dose-dependent production of inositol phosphates; (ii) mobilization of Ca2+ from intracellular stores and (iii) cell contraction. Moreover, at a concentration of 10 microM the agonist was found to induce immediate contractile response of peritubular tissue in freshly explanted tubular fragments from both young and adult rats; the explants were examined in whole-mount preparations and the peritubular myoid cell layer was identified by selective staining for alkaline phosphatase activity. Our observations demonstrate that myoid cells are a direct target for PG F2alpha and suggest a role of the eicosanoid in the intragonadal control of seminiferous tubule contractility
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
Effects of ionizing radiation in biomolecules, cells and tissue/organs: basic mechanisms and applications for cancer therapy, medical imaging and radiation protection
No full textVariations 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
Predicting biological effects along hadrontherapy dose profiles by the BIANCA biophysical model
No full textThe BIANCA biophysical model of cell death and chromosome aberrations was further refined and applied to predict the biological effectiveness along Spread-Out Bragg Peaks used in hadrontherapy. The simulation outcomes were compared with in vitro survival data on protons, He-ions and C-ions over a wide LET range, and the particle- and LET-dependence of the DNA Cluster Lesions (CLs) yields used as input parameters was investigated. For each particle type, the CL yield was found to increase with LET in a linear-quadratic fashion; fitting the CL yields allowed to predict cell death and chromosome aberrations in principle at any depth along a longitudinal proton dose profile used at CNAO. A clear increase in effectiveness was found in the SOBP distal region, supporting the idea that, in some cases, the constant proton RBE usually applied in clinics may be a sub-optimal solution
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
- …
