Variability in energy cost of running at the end of a triathlon and a marathon

International audienceThe aim of this study was to investigate the increase in energy cost of running occurring at the end of a triathlon and a marathon event and to link them to the metabolic and hormonal changes, as well as to variations in stride length. Seven subjects took part in 3 experimental situations: a 2 h 15 min triathlon (30 min swimming, 60 min cycling and 45 min running), a 2 h 15 min marathon (MR) were the fast 45 min were run at the same speed as the triathlon run (TR), and a 45 min isolated run (IR) done at triathlon speed. The results show that energy cost during MR was higher than during TR (p < 0.01) (+ 8.9 %). Similar observations were made for pulmonary ventilation (+ 7.9 %) and heart rate (+ 6.3 %). Moreover, the values were significantly greater than the values obtained during the IR. TR and MR lead to greater weight loss (p < 0.01) (2.4±0.3 kg) than IR (1 ± 0.2 kg). The triathlon and the marathon produced a large decrease in plasma volume (respectively 19.6 ± 1.4 % and 12.9 ± 1.1 %) compared to IR (2 ± 0.4 %). Plasma renin activity was higher for the triathlon and the marathon than for the IR (p < 0.01). MR produces a significantly greater increase in plasma free fatty acids (F.F.A.) than TR (p < 0.05) and IR (p < 0.01). In addition, the F.F.A. at the end of TR were significantly higher than IR (p < 0.05). At the end of the trial the mean stride lengths for TR and IR were greater (+ 15 %) (p <0.01) than for MR. This study, carried out with subjects running overground, confirms the decrease in running efficiency previously shown at the end of a laboratory triathlon, and demonstrates that this decrease is lower than that occurring during a marathon

Evidence of antiangiogenic and antimetastatic activities of the recombinant disintegrin domain of metargidin.

Metargidin, a transmembrane protein of the adamalysin family, and integrins, e.g., alpha5beta1 and alphav, are preferentially expressed on endothelial cells on angiogenesis. Furthermore, metargidin interacts with these integrins via its disintegrin domain. In this study, recombinant human disintegrin domain (RDD) was produced in Escherichia coli by subcloning its cDNA into the pGEX-2T vector, and the effect of purified RDD on different steps of angiogenesis was evaluated. At concentrations of 2-10 micro g/ml, RDD exhibited inhibitory activities in a variety of in vitro functional assays, including endothelial cell proliferation and adhesion on the integrin substrates fibronectin, vitronectin, and fibrinogen. RDD (10 micro g/ml) totally abrogated endothelial cell migration and blocked most capillary formation in a three-dimensional fibrin gel. To test RDD efficacy in vivo, the RDD gene inserted into pBi vector containing a tetracycline-inducible promoter was electrotransferred into nude mouse muscle. RDD was successfully synthesized by muscle cells in vivo as shown by immunolabeling and Western blotting. In addition, 78% less MDA-MB-231 tumor growth, associated with strong inhibition of tumor angiogenesis, was observed in athymic mice bearing electrotransferred RDD. Moreover, in the presence of RDD, 74% fewer B16F10 melanoma lung metastases were found in C57BL/6 mice. Taken together, these results identified this RDD as a potent intrinsic inhibitor of angiogenesis, tumor growth, and metastasis, making it a promising tool for use in anticancer treatment

Evidence of antiangiogenic and antimetastatic activities of the recombinant disintegrin domain of metargidin.

Metargidin, a transmembrane protein of the adamalysin family, and integrins, e.g., alpha5beta1 and alphav, are preferentially expressed on endothelial cells on angiogenesis. Furthermore, metargidin interacts with these integrins via its disintegrin domain. In this study, recombinant human disintegrin domain (RDD) was produced in Escherichia coli by subcloning its cDNA into the pGEX-2T vector, and the effect of purified RDD on different steps of angiogenesis was evaluated. At concentrations of 2-10 micro g/ml, RDD exhibited inhibitory activities in a variety of in vitro functional assays, including endothelial cell proliferation and adhesion on the integrin substrates fibronectin, vitronectin, and fibrinogen. RDD (10 micro g/ml) totally abrogated endothelial cell migration and blocked most capillary formation in a three-dimensional fibrin gel. To test RDD efficacy in vivo, the RDD gene inserted into pBi vector containing a tetracycline-inducible promoter was electrotransferred into nude mouse muscle. RDD was successfully synthesized by muscle cells in vivo as shown by immunolabeling and Western blotting. In addition, 78% less MDA-MB-231 tumor growth, associated with strong inhibition of tumor angiogenesis, was observed in athymic mice bearing electrotransferred RDD. Moreover, in the presence of RDD, 74% fewer B16F10 melanoma lung metastases were found in C57BL/6 mice. Taken together, these results identified this RDD as a potent intrinsic inhibitor of angiogenesis, tumor growth, and metastasis, making it a promising tool for use in anticancer treatment