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Human brown fat, adiposity, and cardiometabolic health: New pieces to the puzzle
Full text linkBrown adipose tissue (BAT) is an emerging target against obesity and its related metabolic diseases. Wibmer et al.1 recently reported that human BAT is associated with a healthier fat distribution and improved cardiometabolic health independent of adiposity and fat distribution
The role of brown adipose tissue on substrate metabolism and insulin sensitivity in humans
No full textBrown adipose tissue (BAT) is a recently re-discovered tissue in humans. The role of BAT in thermogenesis and metabolic regulation has been established in rodents. However, the physiological and clinical significance of this tissue in humans has not been proven yet. The purpose of these investigations was to explore the role of BAT in whole-body energy homeostasis, glucose and lipids kinetics, insulin sensitivity, and thermoregulation in humans.
To this end, we studied men with (BAT+) or without (BAT-) detectable BAT under prolonged mild cold and thermoneutral conditions using infusion of stable isotopic tracers, hyperinsulinemic-euglycemic clamps, indirect calorimetry, and positron emission tomography-computed tomography. A novel method was established to sample the supraclavicular BAT depot and white adipose tissue biopsies were collected from the subcutaneous abdominal area.
During cold exposure, only BAT+ individuals demonstrated a significant increase in whole-body resting energy expenditure, free fatty acid oxidation, glucose disposal, and insulin sensitivity. BAT+ individuals also exhibited a higher increase in whole-body lipolysis during cold exposure, compared to the BAT- group, while they were protected from the cold-induced decrease in adipose tissue insulin sensitivity observed in the BAT- group. With regard to thermoregulation, BAT activity was associated with higher tolerance to cold and change in core body temperature. Functional and molecular analyses of brown and white adipose samples demonstrated the increased thermogenic capacity of BAT mitochondria and the cold-induced up-regulation of genes involved in thermogenesis and lipid metabolism in BAT. The newly established BAT biopsy technique was safe and well tolerated.
These results demonstrate a physiologically significant role of BAT in whole-body energy expenditure, glucose and lipid homeostasis, insulin sensitivity, and thermoregulation in humans, and support the notion that human BAT may function as an anti-obesity and anti-diabetic tissue
Effects of Leucine on Skeletal Muscle During 14 d Bed Rest in Middle-aged Adults
No full textAging is associated with a slow, progressive loss of muscle mass and strength. Mechanical unloading, such as that commonly experienced during hospitalization or spaceflight, results in a rapid loss of muscle mass and strength, particularly in older adults. Exercise, a potent countermeasure to such losses, is often impractical in acutely ill patients. The essential amino acid leucine has been shown to acutely stimulate muscle protein synthesis (MPS), a decrease in which mechanistically drives inactivity-induced losses in muscle. This study evaluated the effects of leucine supplementation (0.06 g • kg • meal-1; LEU) with each of three daily meals in middle-aged adults, a largely unstudied age group, during 14 d bed rest (BR) and subsequent 7 d rehabilitation. Primary findings were: 1) leucine attenuated the loss of whole body lean mass during the first 7 d of BR compared to control subjects (LEU: -0.6±0.2 kg vs. CON: -1.1±0.2 kg, p<0.05) and reduced or prevented decrements in knee extensor strength (LEU: -8±3% vs. CON: -15±3%, p<0.05), ankle extensor strength (LEU: -13±5% vs. CON: -20±5%, p<0.05), and knee extensor endurance (LEU: -2±4% vs. CON: -14±3%, p<0.05) during 14 d BR; 2) LEU maintained both post-absorptive and post-prandial MPS during BR; in contrast, BR decreased post-absorptive MPS (pre-BR: 0.061% • h-1 vs. post-BR: 0.043% • h-1, p<0.05); 3) insulin area under the curve during an oral glucose tolerance test was unchanged in LEU after BR (21±8%) but elevated in CON (52±23%, p<0.05) and whole body insulin sensitivity in LEU was significantly increased above pre-BR values after 7 d rehabilitation (17±10% vs. CON: -9±9%, p<0.05). Leucine is an inexpensive, low volume supplement that can be easily incorporated into the daily meals of middle-aged adults to maintain muscle protein synthesis and protect muscle mass, strength, and insulin sensitivity during periods of physical inactivity characteristic of hospitalized acute illness and spaceflight
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
Is car use related with successful aging of older adults? Results from the multinational Mediterranean islands study
Full text linkPURPOSE: The aim of the present work was to evaluate the relation between car use and the level of successful aging of a random sample of older adults living in the Mediterranean basin. METHODS: During 2005-2011, 2749 older (aged 65-100 years) from 22 islands and the rural Mani region (Peloponnesus) of Greece were voluntarily enrolled in the Mediterranean islands cross-sectional study. Sociodemographics, medical conditions, and dietary and lifestyle habits were derived throughout standard procedures. Car use was recorded with a standard binary question. A successful aging index ranging from 0-10 was used. RESULTS: Older adults who used a car on regular basis had significantly higher levels of successful aging, as well as less prevalence of obesity and hypertension while were more physically active (P < .001). After adjusting for several confounders car use was still positively related with elderly islander's successful aging level (beta coefficient [95% confidence interval]: 0.65 [0.54-0.77]). CONCLUSIONS: In conclusion, the activity of car use seems to be an indicator of quality of life among older adults, as measured through successful aging
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
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