1,721,066 research outputs found
Is liver transplantation feasible in patients coinfected with human immunodeficiency virus and hepatitis C virus?
No full textSelenium and other trace elements in the etiology of Parkinson’s disease: a systematic review and meta-analysis of case-control studies
Full text link.INTRODUCTION
Parkinson’s disease (PD) is a neurodegenerative illness recognised as the most common neurological disorder after Alzheimer’s dementia. Whereas the exact PD etiology remains unknown, risk of developing PD seems to be related to an interrelation of genetic and environmental factors, including also altered exposure to trace elements. In this systematic review and meta-analysis, we updated and summarized the results of epidemiologic case-control studies comparing levels of selenium, copper, iron and zinc in PD patients with healthy subjects in either blood (as whole blood, serum or plasma) and cerebrospinal fluid (CSF).
MATERIALS AND METHODS
We performed a systematic PubMed search and we included in our assessment only studies reporting demographic and disease-related characteristics, as well as trace element levels in different specimens (whole blood, serum/plasma and CSF). We then performed a meta-analysis of mean differences of trace element levels between cases and controls, using a random-effect model computing the weighted mean differences (WMD) and corresponding 95% confidence intervals (CI) to assess the association between serum/plasma, whole blood, CSF and selenium, copper, iron and zinc with Parkinson’s disease.
RESULTS
We retrieved 55 papers reporting data for selenium (588 cases and 721 controls), copper (2190 and 2522), iron (2843 and 3434), and zinc (1798 and 1913). Cases showed higher levels of selenium in CSF compared with controls (WMD=5.49; 95%CI 2.82 to 8.15), while levels in serum were similar (WMD=-0.22; -8.05 to 7.62). For copper cases showed higher levels in CSF and lower in serum compared to controls (WMD=1.87; -3.59 to 7.33, and -42.79, -134.35 to 48.76 respectively). Same results were found for iron in CSF (WMD=6.54; -1.97 to 15.04) and in serum/plasma (WMD=-58.19; -106.49 to -9.89 and whole blood (WMD=-95.69; 157.73 to -33.65). On the converse, cases had lower levels of zinc both in CSF (WMD=-7.34; -14.82 to 0.14) and serum/plasma (WMD=-79.93; -143.80 to -16.06).
CONCLUSIONS
Results of this systematic review and meta-analysis suggests that overexposure to environmental selenium, copper and iron may be risk factors for PD onset or progression. Alternatively, some variation in levels of these trace elements may occur as a consequence of the disease. Considering the burden of PD in the world population, further investigation of trace element exposure in this disease is therefore warranted, especially to plan possible prevention measures
Laparoscopic cholecystectomy in patients with mild cirrhosis and symptomatic cholelithiasis
No full textDietary intake of acrylamide and risk of breast, endometrial and ovarian cancer: a systematic review and dose-response meta-analysis
No full textBackground: Acrylamide is probable human carcinogen that occurs naturally in starchy foods during cooking processes at high temperatures. Aside from occupational exposures and smoking, main source of human exposure is diet, particularly consumption of potatoes, grain products, and coffee. High acrylamide intake has been associated with altered sex-steroid hormone concentrations and increased risk of hormone-dependent gynecologic neoplasms. Objective: We performed a systematic review of the papers investigating the association between acrylamide intake and risk of breast, endometrial and ovarian cancer. We also examined a possible dose-response relation by carrying out a dose-response meta-analysis of these studies. Methods: We searched in PubMed up to September 10, 2019 the non-experimental human studies investigating risk of breast, endometrial, or ovarian cancer in relation to dietary intake of acrylamide. We also carried out a dose-response meta-analysis using a restricted cubic spline model. Results: We retrieved 18 studies: 11 cohort, 5 case-cohort, and 2 case-control studies. Since some studies assessed more than one cancer type, we found a total of ten studies on risk of breast cancer, seven on endometrial cancer, and seven on ovarian cancer. In the dose-response meta-analysis, acrylamide intake was associated with slightly increased risks of endometrial and ovarian cancers, with a stronger and almost linear increased risk among never smokers. Conversely, for breast cancer we found no evidence to support an increased risk following acrylamide exposure, except for a positive association among premenopausal women exposed to at least 20 μg/day of acrylamide. Conclusions: Based on the relatively small number of studies published to date, acrylamide intake was associated with increased risk of endometrial and ovarian cancer in a dose-response fashion, with a slightly stronger association observed among never smokers. Acrylamide intake was associated with an increased risk of breast cancer only among premenopausal women and at intakes greater than 20 μg/day
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
Laparoscopic sleeve gastrectomy as a weight reduction strategy in obese patients after kidney transplantation
No full textLetter to the edito
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