1,721,843 research outputs found
Comparative examination of the expression of tissue cyst markers in Hammondia sp isolated from dogs and foxes
No full textComparative examination of the expression of tissue cyst markers in Hammondia sp isolated from dogs and foxes
No full textA Hammondia-like parasite from the European fox (Vulpes vulpes) forms biologically viable tissue cysts in cell culture
No full textTissue cysts of parasites of the genus Hammondia are rarely described in naturally or experimentally infected intermediate hosts, However, ultrastructural examinations on tissue cyst stages of Hammondia sp. are needed, e.g. to compare these stages with those of Neospora caninum and other related parasites. We describe a cell culture system employed to examine the in vitro development of tissue cysts of a Hammondia sp.-like parasite (isolate FOX 2000/1) which uses the European fox as a definitive host. Cells of a diploid finite cell line from embryonal bovine heart (KH-R CCLV, RIE 090) were infected by inoculation of sporozoites und cultivated for up to 3 months. Transmission electron microscopic examination of 17 day old cell culture material revealed the presence of cyst walls. Infected cell cultures cultivated for 2 months were used to feed a fox. Six to 13 days post infection the fox shed large number,, (n = 1.2 X 10(7)) of Hammondia-sp. like oocysts which could not be distinguished from those used to infect the Cell Culture as determined by DNA sequencing of the internal transcribed spacer I and the D2/D3 domain of the large subunit ribosomal DNA, To find out the proportion of parasitophorous vacuoles that had developed into tissue cysts. the expression of bradyzoite markers was examined by probing infected cell cultures with Mouse polyclonal antibodies against Toxoplasma gondii bradyzoitc antigen I (anti-BAG1) and rat monoclonal antibodies against a cyst wall protein (mAbCC2). Nineteen and 90 days post infection all parasitophorous vacuoles in the cell cultures were positive with anti-BAG1 and mAbCC2. This shows that biologically viable (i.e. infectious) tissue cysts of a fox-derived Hammondia sp. isolate (FOX 2000/1) can be efficiently produced in this cell culture system. Since in Nitro cystogenesis of dog-derived Hammondia heydorni has not been observed et, in vitro cyst formation might be one trait to separate fox-derived Hammondia sp. from H. heydorni on a species level. (C) 2003 Australian Society for Parasitology Inc. Published by Elsevier Science Ltd. All rights reserved
Genotyping of samples from German patients with ocular, cerebral and systemic toxoplasmosis reveals a predominance of Toxoplasma gondii type II
No full textToxoplasmosis is an important zoonosis transmitted from animals to humans world-wide. In order to determine Toxoplasma gondii genotypes in individuals living in Germany and to compare findings with those in animals, we analysed nine independent and unlinked genetic markers (nSAG2, SAG3, BTUS, GRA6, c22-8, c29-2, 1358, PI(I and Apico) by PCR-RFLP in 83 archived T. gondii-positive DNA samples from patients with ocular toxoplasmosis (n=35), toxoplasmic encephalitis (n=32), systemic toxoplasmosis after bone-marrow transplantation (n = 15) and congenital toxoplasmosis (n = 1). In 46 of these 83 samples the presence of T. gondii DNA was confirmed by conventional end-point PCR. Among these, 17 T. gondii-positive samples were typed at all nine loci. The majority (15/17, 88.2%) of these samples were of T. gondii type II (i.e., including both, the Apico type II and Apico type I variants). In addition, in one sample a T. gondii type II/type III allele combination and in another sample a T. gondii genotype displaying type III alleles at all markers was observed. In the remaining 11 samples, in which T. gondii could only be partially typed, exclusively type II (n =10) or type III (n =1) alleles were observed. Results of the present study suggest that the majority of patients in Germany are infected with type II T. gondii regardless of the clinical manifestation of toxoplasmosis. This finding is in accord with the predominance of type II T. gondii in oocysts isolated from cats and in tissues of other intermediate hosts in Germany. (C) 2014 Elsevier GmbH. All rights reserved
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
Rechnungen mit Wirt : Zitationsvergleich 1998 bis 2000: Parasitologie
No full textDas Interesse an Parasiten ist durchaus vielfältig. Und kommt nicht nur aus medizinischen Disziplinen.
"Schmarotzerkunde" nannten die Deutschen früher in ihrer Sprache die Parasitologie. Und definieren sie bis heute als "die Wissenschaft von Parasiten, ihrer Lebensweise und ihren Wechselwirkungen mit Wirt und Umwelt". Wobei streng genommen nur eukaryotische Organismen gemeint sind: Protozoen, Würmer, Insekten und Spinnentiere in der Hauptsache.
Damit ist die Parasitologie ist ein wohldefiniertes Feld, denkt man. Wer sich mit eukaryotischen Organismen beschäftigt, die schmarozend in anderen leben, sollte demnach Parasitologe sein. Größtenteils ist das sicher auch so. Auszuschließen wären allenfalls diejenigen, die sich ausgerechnet einen parasitären Organismus als Modellobjekt für irgendwelche biochemisch oder sonstwie motivierten Studien erkoren haben. Solche also, denen es gar nicht um den Schmarotzer selbst geht. Aber das kommt selten vor.
Dennoch schadet es nicht, ein wenig zu differenzieren. Denn naturgemäß sind Parasiten aus mehreren verschiedenen Richtungen interessant. Da sind sicherlich zuerst einmal die Mediziner und Veterinäre, die vor allem den Kampf gegen pathogene Parasiten im Sinn haben. Insbesondere also Infektionsmediziner, Tropenmediziner, vielleicht auch noch ein paar Pathologen
Staatliche Experten bestätigen: Schlimmster Geflügelpest-Ausbruch aller Zeiten
No full textDer aktuelle Seuchenzug der Vogelgrippe ist der schlimmste jemals in Deutschland registrierte Ausbruch
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