1,720,993 research outputs found
Risk of duodenal adenomas in familial adenomatous polyposis to progress toward advanced neoplastic disease
No full textTo the Editor:
In the February 1, 2004, issue of the Journal of Clinical Oncology, Saurin et al1 report that 50% of duodenal adenomas in familial adenomatous polyposis (FAP) patients progress toward more advanced disease during a mean follow-up period of 47.9 months. As the same authors observe, this value is higher than other published data. In our experience, only two (6.2%) of 32 FAP patients who are taking part of a study for identification of prognostic factors2 show an increased severity of the duodenal lesions after a mean surveillance period of 72.5 months. Moreover, until now, none of these patients have developed the most severe stage of the disease.
The authors justified their results because the very accurate duodenoscopic methodology adopted in the study. This hypothesis can be shared as far as the detection of progression of the lesions is concerned, but it cannot explain the cumulative high number of high scores. At the end of the study period, the percentage of patients with severe lesions (stage IV) was 35%. High-grade dysplasia has been found in 37.1%. It is difficult to hypothesize that lesions like those described in the article could have been underestimated or missed in the available studies reporting lower percentage. The high-grade lesions are also usually detectable also by routine endoscopic examinations.
To know the profile of the population under study may be crucial in these works. It may make the difference. In the Saurin et al article, we do not have the results of the molecular analysis of the patients who have progressed toward the high grade. Moreover, more information on clinical data should be available. In particular, the number of patients with ileoanal anastomosis may be of interest because they have a defective absorption of bile acids, which are involved in the risk of developing duodenal neoplasia.3
The last part of the article discusses the alternative role of endoscopy surgery in the prevention of duodenal cancer. The authors don't comment on the treatment with pharmacologic agents (ie, COX-2 inhibitors, which is a very promising field of prevention).4 Endoscopy should also be improved to increase evaluation efficiency in chemoprevention policy
Serological and histological aspects of hepatitis C virus infection in alcoholic patients
No full textThe recent cloning of the genome of hepatitis C virus (HCV) has allowed the detection of antibodies to HCV (anti-HCV) in human serum. The presence of serum antibodies to HCV often indicates active infection with HCV. We have assessed the serological and histological features in a group of alcoholic patients with chronic liver disease and have evaluated the possible etiologic rote of HCV infection in the development of liver damage. Serum samples and liver biopsy specimens were obtained from 41 consecutive patients, all having a definite history of alcohol abuse and evidence of chronic hypertransaminasemia. Fifteen patients (37%) were positive for anti-HCV by ELISA, and 13 (86.6%) of them were also positive by RIBA. Eleven of these patients had histologic features of chronic active hepatitis (CAH), a lesion which is not known to be induced by excessive alcohol intake. No other possible causes of CAH were found, and CAH was not present in any of the anti-HCV negative patients. In patients with CAH, mean AST to ALT ratio was less than 1 (0.6), a finding which is characteristic of viral rather than alcoholic chronic liver disease. In conclusion, our study suggests that sporadic hepatitis C virus infection plays an etiologic role in the development of chronic active liver disease in a subgroup of alcoholic patients. © 1991
Comparative results of esophageal damage in GERD and DGER: Dilation of intercellular spaces as a marker of esophageal injury
No full textGoing 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
Circadian variations of rectal cell proliferation in patients affected by advanced colorectal cancer.
No full textThe circadian rhythm of the rectal cell proliferation was studied in five patients affected by advanced colon cancer. Biopsies were taken from apparently normal mucosa at 10 cm from the anal verge, every 6 h in a 24-h period. Fragments were incubated for 1 h in a culture medium containing bromodeoxyuridine (BrdUrd). As compared with the mean 24 h values, the percentage of BrdUrd-labelled cells in the crypts (Labelling Index, LI) was lower in the specimens collected at 10.00 PM (P = 0.02) The LI in such biopsies was also lower than the LI observed at the baseline time, 10.00 AM (P = 0.001) The results suggest that the rectal cell proliferation in patients with advanced colon cancer fluctuates during the day. The study of the rhythmicity of the intestinal cells may be useful to modulate the infusion of antiproliferative agents to prevent damage of the normal colorectal mucosa
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
- …
