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Abstract IA09: Beyond counting: Imaging flow cytometry-based detection of therapeutic molecular targets in circulating tumor cells
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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
Circulating tumor cells and cell-free nucleic acids in preclinical models and clinical samples
No full textZirkulierende Tumorzellen (CTCs), zellfreie Nukleinsäuren (cfDNA) oder
tumorspezifische DNA-Moleküle (ctDNA) können entscheidende Informationen für
die Diagnostik, die Therapieüberwachung und die Prognoseeinschätzung von
Krebspatienten liefern. Die tumorspezifischen Biomarker (CTCs und ctDNA)
können zudem als „flüssige Biopsie“ eine Alternative zur herkömmlichen
Charakterisierung von Tumorzellen aus Gewebeproben sein und ermöglichen
demzufolge auch molekularbiologische Untersuchungen von „nicht-biopsierbaren“
Patienten, wodurch individuelle Therapiestrategien gewählt werden können. In
der vorliegenden Arbeit wurden verschiedene Verfahren für den CTC-Nachweis im
Blut von präklinischen Xenograftmodellen miteinander verglichen. Es kann
gezeigt werden, dass mobile und metastasierte Tumorzellen Prozesse
durchlaufen, die den Verlust von epithelialen Markern wie z.B. EpCAM oder
MUC-1 beinhalten, weshalb ein CTC-Nachweis über epitheliale
Oberflächenmoleküle im Vergleich zu antigenunabhängigen Methoden in vivo
erfolglos bleibt. Darüber hinaus kann in Übereinstimmung zur klinischen
Situation die Induzierung von mesenchymalen Markern wie EGFR oder Twist auf
CTCs gezeigt werden. Da im klinischen Alltag zahlreiche Verfahren zum Nachweis
der CTCs auf dem Prinzip der „epithelialen Selektion“ basieren, müssen
demzufolge neue Strategien entwickelt werden, die zusätzlich auch mesenchymale
CTC-Populationen im Blut der Patienten detektieren können. Die Wirkung von
Arzneistoffen kann über qualitative CTC-Messungen im Tiermodell nicht verfolgt
werden. Allerdings kann der Erfolg einer Therapie über die molekulare Analyse
der tumorspezifischen DNA-Moleküle im Plasma der Xenografts gemessen werden.
Über die Bestimmung der humanen, zellfreien Nukleinsäuren lassen sich DNA-
Moleküle im Plasma der Tiere nachweisen, die die Progression des Tumors
molekular abbilden, wobei kein Unterschied zwischen subkutanen und orthotopen
Modellen zu erkennen ist. Signifikant erhöhte Konzentrationen an zellfreien
Nukleinsäuren können zudem auch im Plasma von Krebspatienten im Vergleich zu
Proben von gesunden Individuen nachgewiesen werden. Plasmaproben der
Kolonkrebskohorte zeigen überdies eine Korrelation zwischen der cfDNA-Menge
und dem Metastasestatus, was die Bedeutung der cfDNA-Quantifizierung in
Humanproben demonstriert.Circulating tumor cells (CTCs), circulating cell-free DNA (cfDNA), or tumor-
specific cell-free DNA-molecules (ctDNA) have been suggested as cancer
biomarkers. These biomarkers might give useful information as diagnostic,
prognostic, and monitoring markers in cancer patients. In addition,
tumorspecific CTCs or ctDNA-molecules may be used as “liquid biopsy” for
molecular targeted agents, enabling the identification of patients who will
most likely respond to a given treatment. In this work the performance of
different protocols for CTC detection were established (ex vivo) and used for
blood sample analysis of murine breast cancer xenograft models (in vivo). It
was possible to show that tumor cells which detached from the primary tumor
undergo molecular processes in vivo. These modifications include the down
regulation of epithelial markers, like EpCAM or MUC-1. The use of EpCAM-based
enrichment techniques lead to the loss of CTC populations having undergone
EMT. However, the presence of CTCs could be demonstrated by antibody-
independent detection methods. Moreover, in accordance to the clinical
situation, it could be shown that CTCs up regulate mesenchymal markers, like
EGFR or Twist while circulating through the bloodstream. As numerous
techniques for CTC detection in clinical practice are based on epithelial
markers, new strategies have to be developed which have to detect mesenchymal-
like CTC populations, as well. Further, qualitative measurement of CTCs does
not reflect efficacy of the therapy in animal models of breast cancer.
However, success of therapy can be monitored targeting tumorspecific cell-free
DNA-molecules in plasma samples gained from the used xenografts. This approach
was successfully used for subcutaneous or orthotopic models.In addition,
significantly increased concentrations of cell-free nucleic acids could be
detected in plasma of cancer patients compared to healthy individuals. Plasma
samples of colorectal cancer patients also indicated a correlation between the
quantity and the appearance of metastasis, demonstrating the potential
relevance of cfDNA in human samples for the use in the clinical setting
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
Prestaining of PCR products with SYBR Green for agarose gel electrophoresis: advantages and limitations
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