1,720,959 research outputs found
Grafting of Neonatal Marmoset Monkey Testicular Single-Cell Suspensions into Immunodeficient Mice Leads to ex situ Testicular Cord Neomorphogenesis
No full textSingle-cell suspensions derived from immature rodent and ungulate testes can reconstitute testicular cords upon grafting into immunodeficient mice. In the present study, neonatal common marmoset monkey (Callithrix jacchus) testes were digested to a single-cell suspension, which was transplanted subcutaneously into immunodeficient mice. After 9 or 18 weeks of incubation, the derivatives of the grafted single-cell suspensions were retrieved and analyzed histologically and immunohistochemically. Three of 4 (75%) neonatal grafts exhibited reconstituted seminiferous cords strongly resembling seminiferous cords of the intact neonatal testis. The cords consisted of Sertoli cells, germ cells and peritubular myoid cells, which was confirmed by immunohistochemical marker analysis. Three-dimensional reconstruction models of the grafts revealed elongated tubules. Some of the tubules were branched, which occurs also in vivo, as we show here for the marmoset monkey. Importantly, no teratoma formation by immature pluripotency factor-expressing germ cells was observed. In summary, the reconstituted testicular cords were almost indistinguishable from the cords formed in situ, thereby impressively demonstrating a very high reconstructive potential of a single-cell suspension obtained from the neonatal marmoset monkey testis. To our knowledge, this is the first study demonstrating testicular cord neomorphogenesis for a primate species ex situ. (C) 2013 S. Karger AG, Base
Kisspeptin signalling in the physiology and pathophysiology of the urogenital system
No full textKisspeptin is a peptide hormone, which signals via the G-protein-coupled kisspeptin receptor (KISS1R). Kisspeptin-KISS1R signalling has been implicated in various physiological and pathophysiological processes in the urogenital system, including critical roles in ovarian function as a key player in the regulation of oocyte development. Kisspeptin also has roles in several different functions of the male reproductive tract, such as spermatogenesis and sperm capacitation, and is also thought to be involved in kidney physiology-studies in preclinical animal models have reported that expression of kisspeptin and/or KISS1R is altered in chronically impaired kidneys. The wider importance of kisspeptin action in the urogenital tract has been highlighted by the finding that it suppresses metastasis of urogenital carcinomas; besides the possible therapeutic potential of this finding, tissue and tumour-stage-specific alterations in kisspeptin and KISS1/KISS1R expression could potentially be used as biomarkers for the diagnosis and prognosis of urogenital carcinomas
Epithelial-mesenchymal transition in rhesus monkey embryonic stem cell colonies: A model for processes involved in gastrulation?
No full textA characteristic feature of embryonic stem (ES) cells is their ability to give rise to differentiated cell types that are derived from all three primary germ layers. In the embryo of higher vertebrates, formation of mesoderm and definitive endoderm (gastrulation) occurs at the primitive streak through a spatially highly ordered process of cell ingression, combined with epithelial-mesenchymal transition (EMT). With respect to ES cell differentiation in vitro, however, germ layer derivative formation has not been studied in much detail, and data on any degree of spatial order that may be attained here are lacking. In the investigations to be reviewed here, rhesus monkey ES cells (line R366.4) were grown on mouse embryonic fibroblast feeder layers for up to 10 days during which time they formed multilayered disc-like colonies with an upper epithelial and a lower mesenchymal cell layer. Processes of epithelialization as well as EMT were studied by transmission electron microscopy, immunohistochemistry combined with confocal laser scanning microscopy, and marker mRNA expression (in situ hybridization, RT-PCR). It was found that under the culture conditions used most of the ES cell colonies developed transitorily a central pit where the epithelial upper layer cells underwent an EMT-like process and appeared to ingress to form the lower, mesenchymal layer, accompanied by appropriate changes of morphology and molecular markers. Similarities and differences in comparison with gastrulation/primitive streak formation in vivo are briefly discussed, as are ethical implications with respect to human ES cells. It is concluded that this rhesus ES cell colony system may be an interesting in vitro model for studies on some basic processes involved in early embryogenesis such as EMT/gastrulation and may open new ways to study the regulation of these processes experimentally in vitro in non-human primates. Copyright (c) 2007 S. Karger AG, Basel
Antisera against Neisseria gonorrhoeae cross-react with specific brain proteins of the common marmoset monkey and other nonhuman primate species
No full textPrenatal maternal infections with Neisseria gonorrhoeae (NG) correlate with an increased lifetime probability for the offspring to develop psychosis. We could previously demonstrate that in human choroid plexus papilloma cells, anti-NG antibodies (alpha-NG) bind to mitochondrial proteins HSP60 and ATPB, and interfere with cellular energy metabolism. To assess the in vivo relevance for this, especially during prenatal neural development, we investigated here interactions of NG-specific antisera (alpha-NG1, alpha-NG2) with brain, choroid plexus and other non -neural tissues in pre-and perinatal samples of the nonhuman primate (NHP) Callithrix jacchus (C1), a NHP model for preclinical research. In histological sections at embryonic day E75, immunohistochemistry revealed alpha-NG1 and -2-staining in choroid plexus, ganglionic hill, optic cup, heart, and liver. Within the cells, organelle -like structures were labeled, which could be identified by immunohistochemical double -labeling as mitochondria. Both one-and two-dimensional Western blot analysis revealed tissue specific patterns of alpha-NG1 immunoreactive bands and spots, respectively, which were subsequently characterized by mass spectrometry. Thereby we could confirm the interactions of alpha-NG1 with human HSP60 and ATPB also in CJ choroid plexus and liver. Even more important, in the CJ brain, several new targets, including NCAM1, CRMP2, and SYT1, were identified, which by unrelated studies have been previously suggested to correlate with an increased schizophrenia risk. These findings support the idea that the marmoset monkey is a useful NHP model to investigate the role of maternal bacterial infections during prenatal brain development, and thereby might improve the understanding of this important aspect of schizophrenia pathology
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
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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