1,721,045 research outputs found
Morphological and histochemical features of the luminal epithelium of caudal region of the equine oviduct
No full textThe caudal region of the mammalian oviduct includes the isthmus and utero-tubal junction segments. In equine oviduct a few studies have been performed on the isthmus by means of scanning electron microscopy (SEM) and lectin histochemistry, whereas studies on the interstitial segment of isthmus (ISI) (corresponding to the cow and pig utero-tubal junction) are lacking. These two segments of mare oviducts were processed for SEM and electron transmission microscopy as well as for lectin histochemistry. The ISI showed a narrower lumen and a taller epithelium than isthmus. The epithelium of the both regions contained electron-lucent ciliated cells and two sub-types of non-ciliated (secretory) cell. Most secretory cells in the ISI showed granules characterized by a dense core surrounded by less electron-dense material, whereas a few cells showed an electron-dense cytoplasm containing small electron-dense granules. In the isthmus non-ciliated cells were moderately electron-dense and the two sub-types differed in the number and the electron-density of the granules. Lectin histochemistry showed Galβ1,3GalNAc and sialic acid-Galβ1,3GalNAc in the ISI and Neu5Acα2,6Gal/GalNAc in both segments. These results suggest that during their passage through the ISI and the isthmus spermatozoa move in two different intraluminal milieu which contribute to ensuring the effective condition of the sperm when ovulation occurs
Immunohistochemical localization of the mu-opioid receptor in the bovine uterus
No full textEndogenous opioid peptides play an important role in the regulation of the reproductive system. These peptides act through three main subtypes of opioid receptors: μ, δ, κ. The μ-opioid receptor (MOR) is the primary site of action of several endogenous opioid peptides. The expression of MOR protein has been found in the bovine uterus, but its cellular location is not known. The aim of this study was to localize the MOR in the bovine uterus by means of immunohistochemistry. Tissue fragments were fixed overnight in 4% (w/v) phosphate-buffered paraformaldehyde at 4 °C and routinely embedded in paraffin wax. Sections 4 mm thick were cut and, after de-waxing, they were incubated in a 1:1500 dilution of primary rabbit polyclonal antibody against the third extracellular loop of the mouse MOR (Chemicon, Temecula, CA, USA). Immunohistochemical visualisation was obtained using the Vecta-lab “Elite” (ABC) kit (Vector, Burlingame, CA) and by incubating with a DAB solution. MOR was revealed in some scattered cells along the epithelium lining the endomentrium which showed immunoreactivity in most stromal cells. Immunoreactivity was also detected in muscle cells of myometrium and blood vessels. Since the expression of MOR was observed in both the endometrium and the myometrium, it is possible to infer that in bovine uterus, as in other mammals (Zhu and Pintar 1998, Biol. Reprod. 195: 451-5), the endogenous opioid system could be implicated in the embryo-maternal interaction, in the uterine contractility and in the analgesia
Glycohistochemical characterization of sialoglycoconjugates in the allantoic duct epithelium of the horse umbilical cord
No full textIntroduction: The umbilical cord is the lifeline between the fetus and placenta. The glycoproteins are involved in many biological activities including cell proliferation and cell differentiation. Because of their negative charge and terminal location, sialic acids present a high potential in modulating epithelial permeability barrier and cytoprotective function in the urinary system. The aim of the present study was to examine and characterize sialoglycoproteins in the epithelium lining the allantoic duct by means of the lectin histochemistry.
Methods: Fragments of the umbilical cord from fetuses were fixed in 4% (w/v) neutral formalin and embedded in paraffin wax. Sections (5 μm thick) were stained with SNA, MAL II, PNA, DBA, Con A, WGA before or after KOH-sialidase (Ks) treatment.
Results: The luminal surface bound MAL II, SNA, Ks-PNA, SBA and Ks-WGA; MAL II did not reacted with the luminal surface of the proximal tract. The urothelium apical region bound MAL II, SBA,SNA, PNA and Ks-WGA in the proximal tract, whereas in the other tracts did not react with MAL II and SBA. Except for vacuolized cells, the entire cytoplasm of the urothelium throughout the ductus bound Con A, whereas some elongated cells reacted with Ks-PNA; the elongated cells of the distal region bound also SBA. Basal region of urothelium linked Ks-WGA.
Conclusions: These results demonstrated the presence of sialoglycoconjugates mostly in the lumnal surface of the epithelium lining the horse allantoic duct as well as their regional difference. These glycoconjugates belong to N-linked type (Con A and Ks-WGA reactivity). Althought similar investigations on the allantoic duct lack, our findings agree with studies on the implication of N-linked sialoglycans in the protection and activity of urothelium. It is noteworthy that asialo- or sialylGalNAcα1,3(LFucα1,2)Galβ1,3/4GlcNAcβ1 terminating glycans (DBA and Ks-DBA reactivity) lack in the horse umbilical cord
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
MODIFICAZIONI DELL’ASSETTO GLICOPROTEICO NELL’EPIDIDIMO DI GATTO TRICOLORE (39,XXY). CHANGES OF GLYCOPROTEIN PATTERN IN THE EPIDIDYMIS OF TRICOLOR CAT (39,XXY)
No full textAppropriate 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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