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Myokine secretion and metabolic pathways under resting and contractile conditions in primary human myotubes: A matter of oxygen level?
No full textDiabetologia (2024) 67 (Suppl 1):S1-S593 1 3 postprandial glycaemic control in fertile women with type 1 diabetes (T1DM) during the absorptive and postabsorptive states. This is especially relevant in T1DM since the amount of prandial insulin in circulation is often different when exercising before lunch (low insulin on board) vs. after lunch (high insulin on board), which considerably affects glucose excursions. We aimed to determine which timing of exercise (exercise before or after lunchtime) is more effective to opti-mise postprandial glycaemic control (18-h, 4-h, and nocturnal post-prandial periods) in women of reproductive age with T1DM. Materials and methods: The MERIT1D study is randomized crosso-ver trial. A total of 13 women at the early-middle follicular phase of the menstrual cycle underwent 2 experimental conditions: pre-meal exercise and post-meal exercise. These tests were conducted in 3 non-consecutive days within an 8-day period, with a wash-out period of 48 h between visits. On the 1 st day (screening visit), women underwent a resting energy expenditure test followed by an incremental walk test using a gas analyser, which allowed us to standardize meal energy content and exercise intensity in the experimental days. In the pre-meal and post-meal exercise days, the meal intake test consisted of a mixed milkshake equivalent to 35% of women's resting energy expenditure, and the exercise stimulus of an individualized 35min submaximal walking test whose intensity was equivalent to the 1 st ventilatory threshold. Postprandial glucose excursions were continuously monitored using last-generation continuous glucose monitoring systems (CGM, Dexcom G7). Participants were instructed to follow the same tailored diet, and physical activity and sleep patterns, in the study days. Results: Regarding the 18-h postprandial period, women spent more time in euglycemia and less time in hyperglycaemia when they exercised after lunchtime compared to before lunchtime. However, these trends were non-significant (evidence of statistical significance, p=0.1). Time in hypoglycaemia was similar between both stimuli (p>0.05). In addition, women showed lower glucose variability (standard deviation of mean CGM glucose levels) in the post-meal vs. pre-meal exercise day (p0.05). Conclusion: Overall, post-meal exercise appeared to be slightly more effective to optimise postprandial glucose excursions in women with T1DM compared to pre-meal exercise, at least in the 18-h postprandial period. Ongoing analyses will shed more light on these results. Background and aims: Physical activity is a powerful tool to prevent and reverse type 2 diabetes. It has been shown that myokines released by contracting skeletal muscle affect glucose homeostasis. Oxygen availability in the skeletal muscle microenvironment, which is lower during (high-intensity) exercise, might be a key regulator involved in myokine secretion and glucose uptake in skeletal muscle cells. Here, we investigated the effects of oxygen level on myokine secretion and metabolic pathways under resting and contractile conditions in primary human myotubes. Materials and methods: Ex vivo primary human satellite cells were differentiated towards functional myotubes and exposed to different oxygen levels for 3h (1% vs 3% vs 21% O 2) under resting or contractile (Electrical Pulse Stimulation (EPS), 30V, 1Hz, 2ms) conditions (n=7 independent experiments, 6 biological replicates/condition). We determined lactate secretion, gene expression (quantitative RT-PCR) and secretion (high-sensitivity ELISA) of several myokines (IL-6, GDF-15, IL-15, SPARC and myonectin) as well as AMPK activation using Western Blotting. Data were analyzed using the non-parametric Kruskal-Wallis test, with Bonferroni's post-hoc test in case of significance. Results: Both EPS and low oxygen availability induced a significant increase in lactate secretion compared to resting, non-contractile conditions and standard laboratory conditions (21% O 2), respectively (both p0.05), except for a modest increase in IL-6 secretion (EPS vs. no EPS at 21% O 2 , p=0.025). Effects of low oxygen exposure with(out) EPS on AMPK activation and glucose uptake are currently being examined. Conclusion: The present findings demonstrate that both contraction and a reduced oxygen availability in the skeletal muscle microenvi-ronment induce a shift towards anaerobic (glycolytic) metabolism and affect myokine expression/secretion.EFSD Anniversary Fund Programme - Boehringer Ingelheim; Lilly; NovoNordisk; FWO [11C4423N
Myokine secretion and metabolic pathways under resting and contractile conditions in primary human myotubes: A matter of oxygen level?
No full textDiabetologia (2024) 67 (Suppl 1):S1-S593 1 3 postprandial glycaemic control in fertile women with type 1 diabetes (T1DM) during the absorptive and postabsorptive states. This is especially relevant in T1DM since the amount of prandial insulin in circulation is often different when exercising before lunch (low insulin on board) vs. after lunch (high insulin on board), which considerably affects glucose excursions. We aimed to determine which timing of exercise (exercise before or after lunchtime) is more effective to opti-mise postprandial glycaemic control (18-h, 4-h, and nocturnal post-prandial periods) in women of reproductive age with T1DM. Materials and methods: The MERIT1D study is randomized crosso-ver trial. A total of 13 women at the early-middle follicular phase of the menstrual cycle underwent 2 experimental conditions: pre-meal exercise and post-meal exercise. These tests were conducted in 3 non-consecutive days within an 8-day period, with a wash-out period of 48 h between visits. On the 1 st day (screening visit), women underwent a resting energy expenditure test followed by an incremental walk test using a gas analyser, which allowed us to standardize meal energy content and exercise intensity in the experimental days. In the pre-meal and post-meal exercise days, the meal intake test consisted of a mixed milkshake equivalent to 35% of women's resting energy expenditure, and the exercise stimulus of an individualized 35min submaximal walking test whose intensity was equivalent to the 1 st ventilatory threshold. Postprandial glucose excursions were continuously monitored using last-generation continuous glucose monitoring systems (CGM, Dexcom G7). Participants were instructed to follow the same tailored diet, and physical activity and sleep patterns, in the study days. Results: Regarding the 18-h postprandial period, women spent more time in euglycemia and less time in hyperglycaemia when they exercised after lunchtime compared to before lunchtime. However, these trends were non-significant (evidence of statistical significance, p=0.1). Time in hypoglycaemia was similar between both stimuli (p>0.05). In addition, women showed lower glucose variability (standard deviation of mean CGM glucose levels) in the post-meal vs. pre-meal exercise day (p0.05). Conclusion: Overall, post-meal exercise appeared to be slightly more effective to optimise postprandial glucose excursions in women with T1DM compared to pre-meal exercise, at least in the 18-h postprandial period. Ongoing analyses will shed more light on these results. Background and aims: Physical activity is a powerful tool to prevent and reverse type 2 diabetes. It has been shown that myokines released by contracting skeletal muscle affect glucose homeostasis. Oxygen availability in the skeletal muscle microenvironment, which is lower during (high-intensity) exercise, might be a key regulator involved in myokine secretion and glucose uptake in skeletal muscle cells. Here, we investigated the effects of oxygen level on myokine secretion and metabolic pathways under resting and contractile conditions in primary human myotubes. Materials and methods: Ex vivo primary human satellite cells were differentiated towards functional myotubes and exposed to different oxygen levels for 3h (1% vs 3% vs 21% O 2) under resting or contractile (Electrical Pulse Stimulation (EPS), 30V, 1Hz, 2ms) conditions (n=7 independent experiments, 6 biological replicates/condition). We determined lactate secretion, gene expression (quantitative RT-PCR) and secretion (high-sensitivity ELISA) of several myokines (IL-6, GDF-15, IL-15, SPARC and myonectin) as well as AMPK activation using Western Blotting. Data were analyzed using the non-parametric Kruskal-Wallis test, with Bonferroni's post-hoc test in case of significance. Results: Both EPS and low oxygen availability induced a significant increase in lactate secretion compared to resting, non-contractile conditions and standard laboratory conditions (21% O 2), respectively (both p0.05), except for a modest increase in IL-6 secretion (EPS vs. no EPS at 21% O 2 , p=0.025). Effects of low oxygen exposure with(out) EPS on AMPK activation and glucose uptake are currently being examined. Conclusion: The present findings demonstrate that both contraction and a reduced oxygen availability in the skeletal muscle microenvi-ronment induce a shift towards anaerobic (glycolytic) metabolism and affect myokine expression/secretion.EFSD Anniversary Fund Programme - Boehringer Ingelheim; Lilly; NovoNordisk; FWO [11C4423N
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
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
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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