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Serum IGF-I, IGFBP-3, and IGFBP-2 levels during acute and Chronic high altitude exposure
No full textJ Endocrinol Invest 21, Suppl. to n° 7: 155, 199
Serum leptin and lipid variations after a long-distance ski-alpinism race
No full textJ Endocrinol Invest 22, Suppl. to n 4°, 159P, 199
Effect of endurance exercise at sea level and at high altitude on circulating leptin concentrations
No full textLack of effects of circulating thyroid hormone levels on serum leptin concentrations.
No full textLeptin is the protein product of the ob gene, secreted by adipocytes. It has been suggested that it may play an important role in regulating appetite and energy expenditure. The aim of this study was to evaluate a possible interaction of thyroid hormones with the leptin system. We studied 114 adult patients (65 females and 49 males): 36 were affected with primary hypothyroidism (PH), 38 with central hypothyroidism (CH) and 40 with thyrotoxicosis (TT). Patients with CH were studied both before and after 6 months of L-thyroxine replacement therapy. Body mass index (BMI; kg/m2), thyroid function and fasting serum leptin were assessed in all patients. Since BMI has been proved to be the major influencing variable of circulating leptin levels, data were expressed as standard deviation score (SDS) calculated from 393 male and 561 female controls matched for age and BMI. No difference in SDS was recorded between males and females whatever the levels of circulating thyroid hormones. In males, no significant difference was recorded among the SDSs of PH (-0.36 +/- 1.2), TT (-0.35 +/- 1.2) and CH (0.01 +/- 1.4) patients. Females with PH had an SDSs significantly lower than TT females (-0.77 +/- 1.0 vs -0.06 +/- 1.2; P < 0.02), while no significant differences between CH (-0.34 +/- 0.7) and TT females or between CH and PH females were observed. SDS in CH patients after 6 months of L-thyroxine therapy significantly varied only in females (0.25 +/- 1.4). In conclusion, circulating thyroid hormones do not appear to play any relevant role in leptin synthesis and secretion. However, as females with either overt hypo- or hyper-thyroidism or central hypothyroidism after L-thyroxine therapy show differences in their SDSs, a subtle interaction between sex steroids and thyroid status in modulating leptin secretion, at least in women, may occur
Leptin reduction after endurance races differing in duration and energy expenditure
No full textSerum leptin concentrations are reduced in the presence of a negative energy balance. It has been demonstrated, however, that strenuous and prolonged exercise, which induces a marked negative energy balance, is not always followed by a reduction in serum leptin levels. We therefore analysed serum leptin concentrations before and after three endurance races, which differed in duration and energy expenditure (EE), with the aim of clarifying the relationship between the level of EE and the reduction in leptin levels. Forty-five males participated in one of three competitive endurance races, a half-marathon run [21.097 km, estimated EE 1,400 kcal (5,852 kJ)], a ski-alpinism race [about 45 km, estimated EE 5,000 kcal (20,900 kJ)], and an ultramarathon race [100 km, estimated EE 7,000 kcal (29,269 kJ)]. Blood samples for analysis of serum leptin, and plasma free fatty acids (FFA) were collected before and after the races. Pre-race leptin values were significantly correlated with both body mass index and body fat mass (r=0.672 and r=0.699, respectively; P<0.0001). After exercise, serum leptin levels decreased significantly in the ultramarathon [from 4.15 (0.63) μg/l to 1.01 (0.15) μg/l; P<0.001] and in the ski-alpinism race [from 1.10 (0.28) μg/l to 0.62 (0.15) μg/l; P<0.01], but not in the half-marathon [from 1.38 (0.40) μg/l to 1.20 (0.36) μg/l]. Plasma FFA were found to have significantly increased in all three of the races, showing a negative correlation with the percent reduction in leptin (r=0.369, P<0.02). Our data indicate that only a prolonged endurance exercise involving a high EE can induce a marked reduction in circulating serum leptin levels
Different dosage schedules of short term GH therapy: effects on serum leptin levels in accord of GH deficient adults
No full textPoster presentation (P3 - 336
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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