1,720,958 research outputs found
Multi-organ extraosseous99mTC-HMDP uptake in a case of metastatic melanoma
No full text99mTc-diphosphonates are a class of radiopharmaceuticals, used for bone scintigraphy, able to highlight all lesions characterised by altered osteogenesis. We report the case of a 47-year-old male with an end-stage melanoma, presenting a multi-organ extraosseous activity. Patient underwent whole body scintigraphy using a dual head y-camera, equipped with LEHR collimators. Images were obtained at 3 hours from i.v. injection of 700 MBq of 99mTc-HMDP. Radiochemical purity was 98.2%. The scan showed a decreased skeletal and urinary activity, as well as an intense extraosseous activity in the lungs (especially in the right one), in the stomach, in the liver and a bit lesser in the spleen. Unknown skeletal metastases were also identified. At the time of bone scan, the patient had hypercalcemia and an oliguric acute kidney injury caused by sepsis. Moreover, ultrasound and chest radiography showed the presence of hepatic metastases and radiographic signs of pneumonia in the right lung, respectively. Soft tissues calcifications can be classified in two groups: metastatic calcifications, where calcium sediments in normal tissues, and dystrophic calcifications, where this deposit occurs only in previously injured organs. Metastatic calcifications mainly occur in patients in hemodialytic treatment, since the hyperparathyroism and the acidosis, due to the interdialytic interval, induce an hypercalcemia. Moreover, the reduced glomerular filtration causes hyperphosphatemia and, consequently, increased calcium-phosphate products. On the other hand, dystrophic calcifications occur in injured tissues, even without increased serum calcium levels. Our patient had high levels of calcemia, but not a secondary hyperparathyroidism, so other causes must be researched. It's common knowledge that a high level of calcemia can be found in 10 to 20% of cases with advanced cancer. Indeed, the patient had bone metastases and malignant hypercalcemia. The 99mTc-HMDP uptake was different in the two lungs, with a greater intensity in the right one. This pattern is probably due to two causes: hypercalcemia (linked to the end-stage cancer), that explains the bilateral lungs uptake, and an injured tissue, for example in presence of an infection, that generates a greater uptake in the right lung. The increased uptake of 99mTc-HMDP in other patient's organs was probably due to some of mechanisms already involved in pulmonary calcifications. Moreover hepatic image showed a patchy activity, with some areas of more evident calcifications, probably due to the presence of malignant metastases. Malignant hypercalcemia depends on several causes, like the osteoclastic bone resorption and the secretion of parathyroid hormone related protein (PTHrP), and may be associated with extra-skeletal images at bone scintigraphy. A previous oxidant injury can contribute to more intense calcifications in the involved tissues
White blood cell scintigraphy in the diagnosis of infection of endovascular prostheses within the first month after implantation
No full text99mTc-HMPAO-labeled leukocyte scintigraphy (WBCs) is useful in the diagnosis of vascular graft infection. However, false positives can occur in the early postoperative period. There are no data concerning the usefulness of WBCs in detecting endovascular prosthesis infection during this period. The aim of our study was to assess the reliability of WBCs in the diagnosis of early infection after endovascular prosthesis implantation. 23 patients treated with endovascular grafts were submitted to preoperative diagnostic screening and to 3 WBCs (1 week before, 1 week after, and 1 month after surgery). After the last WBCs, all patients underwent a 14-month follow-up (range 6–37 months, median 12 months). Three patients died, at 3, 4 and 5 months after surgery respectively. At the end of the follow-up, the presence of infection was demonstrated in one patient. Of the 70 WBCs performed, 4 gave positive results. No positive scintigraphies were obtained in the preoperative period. A positive scintigraphy was found one week after surgery in a patient who showed lymphorrhage at the site of surgical access. In the same patient, the scintigraphic result returned to normal at 1-month scintigraphy. At 12-month follow-up the patient did not present signs of infection. Three positive scintigraphies were obtained in the same patient. In this patient clinical symptoms of graft infection became evident about 19 months after surgery. WBCs was repeated and showed extension of the infection. The infection was confi rmed at surgery. WBCs do not provide false-positives in the first month after endovascular prosthesis implantatio
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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