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Interventions in the metabolic syndrome: bile acid sequestration and exercise
Get PDFThe prevalence of the metabolic syndrome (MetS) has reached alarming dimensions in the Western World. MetS is comprised of a multitude of risk factors and can lead to serious complications like type 2 diabetes and atherosclerosis. Bile acid sequestrants (BAS), pharmacological agents that increase the fecal excretion of bile acids, and physical activity improve MetS and act beneficial in decreasing high blood glucose and high cholesterol levels, two components of MetS. However, underlying mechanisms are elusive. We evaluated whether the BAS and physical activity induced improvements in MetS are underlying specific changes in glucose-and cholesterol-handling in specific mouse models paralleling human disease.
We found that BAS decrease blood glucose levels by peripheral actions and not by modulations of liver glucose handling. Specifically, we found BAS to increase the clearance of blood glucose which coincided with a number of parameters indicating improved peripheral insulin sensitivity and utilization. Additionally, we found BAS treatment to substantially reduce atherosclerosis development in atherosclerosis-prone mice which is most likely mediated by a switch from bodily cholesterol accumulation to cholesterol loss.
We further established that physical activity beneficially modulates cholesterol metabolism by enhancing its fecal excretion especially as bile acids but also as neutral sterols. This coincided with a reduced development of atherosclerosis and hepatic fat storage. Intriguingly, we found a negative correlation between the amount of physical activity and atherosclerosis development.
Altogether, the studies of this thesis provide novel insights on how BAS and physical activity beneficially affect MetS risk factors and its complications.
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
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Interaction of exercise and simvastatin on myocardial ischemia-reperfusion (I/R) injury and post-ischemic cardiac function
No full textSimvastatin is one of the statins, which are a class of drugs originally developed to fight cardiovascular disease by lowering cholesterol. However, it is now clear that they have effects independent of cholesterol. For example, statin therapy, like exercise, induces adaptations within the heart that protect it against I/R injury. Patients are frequently advised to undergo a combination treatment of statins and chronic exercise, although little is known about how this combination treatment affects cardioprotective adaptations. Both treatments appear to exert their cardioprotective effects through different mechanisms, therefore it appears plausible that combining the two treatments would provide added cardioprotection than either treatment alone. Purpose: To investigate the effects of a combination treatment of statins and exercise upon parameters of post-ischemic myocardial function and damage. Methods: Female Sprague-Dawley rats (6 months of age) were separated into 4 groups for a period of 4 weeks: Sedentary (S, n=10), sedentary plus 10 mg simvastatin (Zocor®)/kg body wt/ day (SD, n=9), exercise (R, n=9), and exercise plus simvastatin (RD, n=9). R and RD were exercised identically on a treadmill for 5 days/week at an intensity of about 70% VO2max and for a duration that was gradually increased to 60 min/day. Twenty-four hrs following the last exercise bout, isolated perfused working hearts were subjected to 30 min of global ischemia followed by 30 min of normoxic reperfusion. Coronary effluents were used to determine lactate dehydrogenase (LDH) leakage and prostaglandin generation. Results: Cardiac function was similar in all groups prior to ischemia. Post I/R recovery of cardiac function in S was 17.6 [greater than or equal to]6.6% of pre-ischemic cardiac output times systolic pressure. Recovery was significantly higher in SD (37.7[greater than or equal to]7.7%) and R (40.1[greater than or equal to]7.8%) and tended to be highest in RD (49.7[greater than or equal to]7.1%). SD had significantly higher pre-ischemic coronary flow per g heart weight (CF/g) than all other groups. At 10 min post-ischemia, simvastatin treatment significantly increased CF/g compared to S (p<0.05). Exercise had an effect on increasing post-ischemic myocardial efficiency and RD had significantly higher post-ischemic myocardial efficiency vs. S (p<0.05). Compared to S, LDH leakage during reperfusion was dramatically decreased in SD, R and RD by approximately similar amounts. Simvastatin treatment doubled the basal production of protective prostaglandins, whereas exercise did not significantly alter their production and combining both treatments yielded a lower prostaglandin release than simvastatin treatment. SD had s significantly higher basal prostaglandin release than R (p<0.05). Conclusion: Although the combination treatment of simvastatin and exercise did not result in a statistically significant addition in cardioprotection compared to either treatment alone, there was a trend for improved parameters of post-ischemic cardiac function and damage upon combining both treatments compared to each treatment alone. Specifically, the prostaglandin, CF/g and efficiency data suggest that exercise and statininduced cardioprotection against I/R injury appears to occur by different mechanisms and combining the two treatments may provide greater protection than either alone.Kinesiology and Health Educatio
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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