1,720,962 research outputs found
Methodological aspects of the immunostaining of proliferating cell nuclear antigen (PCNA) in cytospin preparations of MCF-7 cell line
No full textCytospins of a human breast cancer cell line (MCF‐7) were studied for the expression of PCNA, a cell cycle‐related protein, using a variety of fixation and immunostaining procedures. The best fixative for PCNA was found to be buffered formaldehyde solution at 4°C followed by methanol at 20°C, whereas alcoholic fixatives decreased greatly the PCNA immunoreactivity. Air‐drying procedures of cytospins prior to and after fixation greatly undermined the PCNA immunostaining. A modified immunoperoxidase method provided a stronger staining of the PCNA‐reactive cells than the alkaline phosphatase anti‐alkaline phosphatase (APAAP) technique. PCNA immunoreactivity could be maintained up to 2 mo, putting slides in methanol at − 2°C. In conclusion, our report indicates that PCNA is a labile antigen, which may critically be affected by temperature and air‐drying procedure
Immunocytochemical detection of cell proliferation-related antigens in cytologic smears of human malignant neoplasms using PC10, reactive with proliferating cell nuclear antigen, and Ki-67: A comparative study
No full textCytospins of the MCF-7 cell line and 93 consecutive smears of human malignant neoplasms were immunochemically evaluated for the expression of proliferating cell nuclear antigen (PCNA) and Ki-67-related antigen. Results expressed as the labeling index (LI) were compared with histologic sections. The PCNA LI and Ki-67 LI were lower in cytologic smears than in histologic sections, though the differences were not statistically significant. A positive linear relationship was found between these markers in both cytologic and histologic samples. The PCNA LI was generally lower than the Ki-67 LI, but in seven malignant neoplasms, PCNA LI was greater than the corresponding values of the KI-67 LI. We conclude that cell proliferation can be reliably evaluated on cytologic preparations; PCNA may behave as a Ki-67- like reagent in some tumors, and PCNA may sometimes overestimate the cell growth fraction assessed by Ki-67 immunoreactivity
Endocrine tumors of the pancreas: proliferative activity assessed by Ki-67 immunoreactivity on paraffin sections is an independent predictor for malignancy. A comparative study of survival with immunostaining for PCNA and progesterone receptor protein, mitotic index and other clinicopathologic variables.
No full textEndocrine tumors of the pancreas: proliferative activity assessed by Ki-67 immunoreactivity on paraffin sections is an independent predictor for malignancy. A comparative study of survival with immunostaining for PCNA and progesterone receptor protein, mitotic index and other clinicopathologic variables
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
High-affinity monomeric 67-kD laminin receptors and prognosis in pancreatic endocrine tumours
No full textCell-surface high-affinity monomeric 67-kD laminin receptors have been proposed to promote the invasion and metastasis of a variety of tumours, but there are, as yet, no data regarding the expression of these molecules in pancreatic endocrine tumours (PETs). The prognosis of these very rare tumours is problematic and the only irrefutable evidence of their malignancy still continues to be the occurrence of local invasion and metastases. In this retrospective investigation, 34 functioning and 48 non-functioning sporadic PETs were evaluated for the expression of the MLuC5 monoclonal antibody, which specifically recognizes the 67-kD laminin receptors. Laminin receptors were found in 42/82 cases (51 per cent) and their expression was associated with metastatic disease (P lt 0.001), high proliferative activity expressed by a Ki-67 index above 5.0 per cent (P lt 0.001), absence of progesterone receptors (P=0.013), immunoreactivity for hormones other than insulin (P lt 0.001), a tumour diameter more than 3.0 cm (P=0.001), and a fatal clinical outcome (P lt 0.001). Laminin receptors were also expressed by most metastatic foci and all intravascular emboli of tumour cells. Positivity for receptors was associated with shorter survival in functioning (P=0.026) and non-functioning (P=0.042) turnouts, as well as in the whole series of pancreatic endocrine turnouts (P lt 0.001). On multivariate analysis, laminin receptor expression was not an independent prognostic factor, while a Ki-67 index above 5.0 per cent was the most powerful predictor of survival. However, the association of laminin receptor expression and Ki-67 index could identify a group of malignant PETs with low proliferative activity characterized by sill intermediate prognosis. In conclusion, these data suggest that monomeric laminin receptors may play a role in the invasion and metastasis of PETs and that their expression may be an additional prognostic factor, along with proliferative activity
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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