1,720,971 research outputs found
Gastritis cystica polyposa: a possible precancerous lesion
No full textTwenty polypoid lesions at gastroenterostomy stomas (the so-called gastritis cystica polyposa-GCP) were endoscopically removed from gastroenterostomy stomas of 16 male and two female patients previously operated for benign lesions. The interval from surgery ranged from 3 to 40 years (mean: 16.2 years). At light microscopy GCP showed 2 histologic patterns: a) with cystic glands limited to the mucosal layer (gastritis cystica superficialis); b) with cystic glands also spreading into the submucosa (gastritis cystica profunda). Atrophy of specific gastric glands, intestinal metaplasia and dysplastic changes also occurred. Local chronic ischemia and inflammatory reaction as a consequence of gastric surgery and suture at gastroenterostomy together with bile reflux were considered responsible for the development of GCP. The sites and the histologic features of GCP resembled those of experimental stomal polyps preceeding carcinoma in rats after partial gastrectomy. The sites of formation, the sex incidence, the interval from previous operation as well as the histologic findings suggest that GCP is a possible precancerous lesion
Transitional polyps of the colon
No full textFourteen polps with the gross appearance of small hyperplastic (metaplastic) polyps, not exceeding five mm in diameter, were removed from the rectum and the sigmoid colon of patients during colonscopy, and from surgical specimens. At light microscopy they were seen to be composed of apparently normal mucosa. In most cases some hyperplastic (metaplastic) and adenomatous polyps were also present. HID-AB stain revealed the polyps to be composed of "transitional" mucosa containing almost exclusively sialomucins, in contrast to normal mucosa, in which sulphomucins predominate. It is suggested that these "transitional" polyps may represent a reservoir of hyperplastic (metaplastic) and adenomatous polps, the different fate depending on different environmental situations
"The evolution of the solitary ulcer of the rectum"an endoscopic and histopathological study
No full textA follow-up study of fourteen out of twenty-seven cases of solitary ulcer syndrome of the rectum was performed at one year's interval from the previous endoscopic and histologic examination. Most of the lesions consistently changed their aspect, resulting in incomplete irregular narrowings, polypoid protrusions or linear ulcers. The symptoms remained unchanged or slightly diminished. A striking difference was found in the histological pattern of the "evolved" ulcer in comparison to the active one, the former showing features of hyperplastic (metaplastic) colonic polyps as well as of the so called "transitional mucosa". It is suggested that chronic ischemia occurring in solitary ulcer of the rectum leads to "transitional mucosa" as an exaggerated regenerative phenomenon, hyperplastic (metaplastic) mucosa representing a later maturative phase. Possibly "transitional" mucosa may undergo dysplastic changes under the influence of environmental factors
"Transitional" and hyperplastic-metaplastic mucosa occurring in solitary ulcer of the rectum
No full textNon-polypoid hyperplastic mucosa similar to that adjacent to colorectal carcinomas and adenomas, the so-called "transitional mucosa" (TM), was found in 16 out of 27 cases of solitary ulcer syndrome of the rectum. In 18 cases fully developed hyperplastic (metaplastic) mucosa was also found. It is suggested that chronic ischaemia which takes place in the solitary ulcer syndrome leads to TM as an exaggerated regenerative phenomenon. Later maturation of TM could lead to hyperplastic (metaplastic) changes
Juvenile and inflammatory polyps of the colon--a histological and histochemical study
No full textA light microscopy and histochemical study of 24 juvenile and 27 inflammatory polyps showed that both may derive from inflammatory processes. Granulation tissue, secondary to spontaneous local inflammation or due to surgical procedures may subsequently be covered by regenerating epithelium which lines haemorrhagic cavities and mucus lakes to form irregular, elongated and cystic glands, which are characteristic of juvenile polyps. Both juvenile and inflammatory polyps showed cystic, metaplastic and 'transitional-type' glands. The mucin distribution was identical in both types of polyps. All these findings suggest a common origin of the polyps. The presence of 'transitional-type' glands seems to confirm these as a secondary regenerative phenomenon rather than pre-neoplastic, although dysplastic changes in juvenile polyps have been described. It is suggested that both the juvenile and inflammatory polyps may undergo dysplasia only in genetically predisposed subjects. However, this event seems to be very rare
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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