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Magnetic Resonance Imaging of Single Co-Labeled Mesenchymal Stromal Cells after Intracardial Injection in Mice
No full textPurpose: The aim of this study was to establish co-labeling of mesenchymal stromal cells (MSC) for the detection of single MSC in-vivo by MRI and histological validation. Materials and Methods: Mouse MSC were co-labeled with fluorescent iron oxide micro-particles and carboxyfluorescein succinimidyl ester (CFSE). The cellular iron content was determined by atomic absorption spectrometry. Cell proliferation and expression of characteristic surface markers were determined by flow cytometry. The chondrogenic differentiation capacity was assessed. Different amounts of cells (n1=5000, n2= 15000, n3=50000) were injected into the left heart ventricle of 12 mice. The animals underwent sequential MRI on a clinical 3.0T scanner (Intera, Philips Medical Systems, Best, The Netherlands). For histological validation cryosections were examined by fluorescent microscopy. Results: Magnetic and fluorescent labeling of MSC was established (mean cellular iron content 23.6 3pg). Flow cytometry showed similar cell proliferation and receptor expression of labeled and unlabeled MSC. Chondrogenic differentiation of labeled MSC was verified. After cell injection MRI revealed multiple signal voids in the brain and fewer signal voids in the kidneys. In the brain, an average of 4.61.2 (n1), 9.03.6 (n2) and 25.0 1.0 (n3) signal voids were detected per MRI slice. An average of 8.73.1 (n1), 22.06.1 (n2) and 89.86.5 (n3) labeled cells per corresponding stack of adjacent cryosections could be detected in the brain. Statistical correlation of the numbers of MRI signal voids in the brain and single MSC found by histology revealed a correlation coefficient of r=0.91. Conclusion: The study demonstrates efficient magnetic and fluorescent co-labeling of MSC and their detection on a single cell level in mice by in-vivo MRI and histology. The described techniques may broaden the methods for in-vivo tracking of MSC. Key Points: center dot Detection of single magnetically labeled MSC in-vivo using a clinical 3.0T MRI is possible. center dot Fluorescent and magnetic co-labeling does not affect cell vitality. center dot The number of cells detected by MRI and histology has a high correlation. Citation Format: center dot Salamon J, Wicklein D, Didie M etal. Magnetic Resonance Imaging of Single Co-Labeled Mesenchymal Stromal Cells after Intracardial Injection in Mice. Fortschr Rontgenstr 2014; 186: 367-376 Zusammenfassung Ziel: Etablierung einer Doppelmarkierung mesenchymaler Stromazellen (MSZ) zur in-vivo Detektion einzelner MSZ mittels MRT und zur histologischen Validierung. Material und Methoden: Murine MSZ wurden mit fluoreszierenden Eisenmikropartikeln und Carboxyfluorescein Succinimidyl Ester (CFSE) markiert. Der zellulare Eisengehalt wurde mittels Atomabsorptionsspektrometrie bestimmt. Zellprolieferation und Expression charakteristischer Oberflachenmarker wurden mittels Durchflusszytometrie bestimmt. Die chondrogene Differenzierungskapazitat wurde uberpruft. Verschiedene Zellanzahlen (n1=5000, n2=15000, n3=50000) wurden bei 12 Mausen in den linken Herzventrikel injiziert. Es erfolgte die sequenzielle MRT der Tiere an einem klinischen 3.0T MRT. Zur histologischen Validierung wurden Kryostatschnitte fluoreszensmikroskopisch untersucht. Ergebnisse: Die magnetische und fluoreszierende Doppelmarkierung von MSZ wurde etabliert (mittlerer zellularer Eisengehalt 23,6 +/- 4,3pg). Durchflusszytometrisch zeigten sichahnliche Zellprolieferationsraten und Rezeptorexpressionsprofile von markierten und unmarkierten MSZ. Die chondrogene Differenzierung der doppelt markierten MSZ wurde verifiziert. Nach Zellinjektion zeigten sich im MRT multiple Signalausloschungen im Hirn und geringer in der Niere. Im Hirn fanden sich durchschnittlich 4,6 +/- 1,2 (n1), 9,0 +/- 3,6 (n2) und 25,0 +/- 1,0 (n3) Signalausloschungen pro Schicht. Durchschnittlich fanden sich 8,7 +/- 3,1 (n1), 22,0 +/- 6,1 (n2) und 89,8 +/- 6,5 (n3) Zellen pro korrespondierendem Kryostatschnitt. Die statistische Korrelation der mittels MRT detektierten Signalausloschungen und der histologisch nachgewiesenen Zellen ergab einen Korrelationskoeffizienten von r=0,91. Schlussfolgerung: Die Studie zeigt die erfolgreiche magnetische und fluoreszierende Doppelmarkierung von MSZ und deren Detektion auf Einzelzellniveau mittels in vivo MRT und Histologie. Die beschriebenen Techniken tragen zur Erweiterung der Methoden fur das in vivo Monitoring von MSZ bei. Kernaussagen: center dot Die Detektion einzelner magnetisch markierter Zellen in vivo im 3,0T MRT ist moglich. center dot Die magnetische und Fluoreszenzmarkierung haben keinen negativen Einfluss auf die Zellvitalitat. center dot Die Anzahl mittels MRT und Histologie detektierter Zellen zeigt eine hohe Korrelation
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
Die Bedeutung von CD44 für die Metastasierung des duktalen Pankreasadenokarzinom in einem murinen Xenograftmodell
No full textDas zur Superfamilie der Immunglobuline gehörende CD44 ist ein transmembranöses Glykoprotein, welches vielfältige Funktionen besitzt, die alle abhängig von der Zelladhäsion sind. In der Fachliteratur ist nach wie vor umstritten, welche Bedeutung eine hohe Expression von CD44 für die Metastasierung im humanen duktalen Pankreaskarzinom besitzt. Diese Arbeit beschäftigte sich mit der Frage, welche Auswirkung eine Reduzierung von CD44 im Hinblick auf die Metastasierung und die allgemeine Tumormorphologie in den humanen Pankreaskarzinomzelllinien PaCa 5061 und BxPC3 hervorruft. Hierzu wurde mittels shRNA in den genannten Zelllinien ein Knockdown von CD44 von 90% generiert und in einem subkutanen Xenograftmodell in immundefizienten Mäusen eingesetzt. Dieser Knockdown wurde mit Kontrollgruppen verglichen. Die gewachsenen Tumoren wurden mittels verschiedener histologischer Färbungen (HE, PAS, Masson-Goldner) und Immunhistochemie (CD44, CD24, CD45) begutachtet. Es erfolgte eine lichtmikroskopische Metastasenzählung in den Mauslungen und eine quantitative Real-Time-Polymerasekettenreaktion mit Alu-Sequenzen von Mauslungen und Mausblut. Es zeigte sich eine signifikant höhere Anzahl von Tumozellen pro 106 Mauslungenzellen für die Knockdowngruppe von PaCa 5061 (Alu-PCR p=0,0006; Zählung nicht signifikant p=0,1784) und gleichzeitig eine signifikant höhere Anzahl von Tumorzellen pro 106 Mausleukozyten im Vergleich zur luc-Gruppe. Für BxPC3 konnte eine höhere Anzahl an Tumorzellen pro 106 Mausleukozyten im Knockdown festgestellt werden (knapp nicht signifikant). Die Untersuchung der Alu-PCR der Mauslungen erbrachte für BxPC3 einen höheren Wert in der luc-Gruppe, allerdings ohne Signifikanz (p=0,1432, Zählung signifikant p=0,0004). Im Gesamtüberleben der Tiere fand sich für BxPC3 kein Unterschied, während die Tumoren von PaCa 5061 in der Knockdowngruppe frühzeitig ulzerierten und die luc-Gruppe demnach ein deutlich längeres Überleben zeigte. In der immunhistochemischen Färbung fiel auf, dass die luc-Gruppen CD44 vermehrt am Tumorrand ausbilden, außerdem stellten sich alle untersuchten Mauslungenmetastasen CD44-negativ dar. Zusammenfassend lässt sich sagen, dass die Pankreaskarzinomzellen der Zellinie PaCa 5061, die einem Knockdown von CD44 unterliegen, eine vermehrte Bereitschaft zur Auswanderung ins Blut und eine verstärkte Metastasierungsneigung zeigten. Die Ergebnisse für BxPC3 zeigten eher eine Abnahme der Metastasierung, es fanden sich aber Ähnlichkeiten was das Auswandern der Tumorzellen ins Blut in der Knockdowngruppe im Vergleich zur luc-Gruppe angeht
Der Knockdown von L1CAM reduziert die Metastasierung in einem Xenograftmodel humaner Melanome signifikant: L1CAM ist ein potentielles Ziel für die Therapie von Melanomen
No full textMalignant melanoma is a malignant neoplasia of the skin, which spreads aggressively. After distant metastases had formed almost no chance for cure exists. Thus, it is extremely important to identify druggable targets with different modes of action to enable individualised therapy even after distant metastases have formed and to prevent the formation of further metastases. Different proteins are already known to be promising targets for therapeutic agents because of their metastases promoting potential. One of these proteins, which need to be researched closely, is the surface protein L1 cell adhaesion molecule (L1CAM).
In this work, we investigated the impact of a knockdown of L1CAM protein expression on the ability of malignant melanoma cells to metastasize in in vitro models reflecting part of the metastatic cascade and in vivo in a xenograft model. We chose two different cell lines: MeWo and MV3. It is known that MeWo wild type cells expressed considerably more L1CAM than wildtype MV3 cells.
The in vitro experiments showed no distinct difference in cellular behaviour reflecting metastasis formation between cells with or wildtype cells without L1CAM knockdown.
In vivo however there was a significant reduction in the number of spontaneous metastases into the mouse lungs within both groups of L1CAM knockdown cells. The impact was measurable in both cell lines, in the initially high L1CAM expressing MeWo cells, but also in the initially low L1CAM expressing MV3 cells.
In both cell lines an influence of L1CAM expression on the expression of other genes which modulate epithelial mesenchymal transition or those which suppress melanoma growth such as p53 and p21 were noted.
The significant impact of L1CAM expression on the process of metastasis formation of melanoma cells was shown, which makes L1CAM an interesting novel therapeutic target
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
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