4 research outputs found
High-intensity interval training using electrical stimulation ameliorates muscle fatigue in chronic kidney disease-related cachexia by restoring mitochondrial respiratory dysfunction
BackgroundExercise, especially high-intensity interval training (HIIT), can increase mitochondrial respiratory capacity and enhance muscular endurance, but its systemic burden makes it difficult to safely and continuously prescribe for patients with chronic kidney disease (CKD)-related cachexia who are in poor general condition. In this study, we examined whether HIIT using electrical stimulation (ES), which does not require whole-body exercise, improves muscle endurance in the skeletal muscle of 5/6 nephrectomized rats, a widely used animal model for CKD-related cachexia.MethodsMale Wistar rats (10 weeks old) were randomly assigned to a group of sham-operated (Sham) rats and a group of 5/6 nephrectomy (Nx) rats. HIIT was performed on plantar flexor muscles in vivo with supramaximal ES every other day for 4 weeks to assess muscle endurance, myosin heavy-chain isoforms, and mitochondrial respiratory function in Nx rats. A single session was also performed to identify upstream signaling pathways altered by HIIT using ES.ResultsIn the non-trained plantar flexor muscles from Nx rats, the muscle endurance was significantly lower than that in plantar flexor muscles from Sham rats. The proportion of myosin heavy chain IIa/x, mitochondrial content, mitochondrial respiratory capacity, and formation of mitochondrial respiratory supercomplexes in the plantaris muscle were also significantly decreased in the non-trained plantar flexor muscles from Nx rats than compared to those in plantar flexor muscles from Sham rats. Treatment with HIIT using ES for Nx rats significantly improved these molecular and functional changes to the same degrees as those in Sham rats. Furthermore, a single session of HIIT with ES significantly increased the phosphorylation levels of AMP-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase (MAPK), pathways that are essential for mitochondrial activation signaling by exercise, in the plantar muscles of both Nx and Sham rats.ConclusionThe findings suggest that HIIT using ES ameliorates muscle fatigue in Nx rats via restoration of mitochondrial respiratory dysfunction with activation of AMPK and p38 MAPK signaling. Our ES-based HIIT protocol can be performed without placing a burden on the whole body and be a promising intervention that is implemented even in conditions of reduced general performance status such as CKD-related cachexia
An Unbiased CO Survey Toward the Northern Region of the Small Magellanic Cloud with the Atacama Compact Array. II. CO Cloud Catalog
The nature of molecular clouds and their statistical behavior in sub-solar
metallicity environments are not fully explored yet. We analyzed an unbiased
CO( = 2-1) survey data at a spatial resolution of 2 pc in the northern
region of the Small Magellanic Cloud (SMC) with the Atacama Compact Array to
characterize the CO cloud properties. A cloud decomposition analysis identified
426 spatially/velocity-independent CO clouds and their substructures. Based on
the cross-matching with known infrared catalogs by Spitzer and Herschel, more
than 90% CO clouds show spatial correlations with point sources. We
investigated the basic properties of the CO clouds and found that the
radius-velocity linewidth (-) relation follows the Milky Way
(MW) like power-low exponent, but the intercept is 1.5 times lower than
that in the MW. The mass functions () of the CO luminosity and virial
mass are characterized by an exponent of 1.7, which is consistent with
previously reported values in the Large Magellanic Cloud and MW.Comment: 18 pages, 9 figures. Accepted for publication in The Astrophysical
Journa
Occurrence and recent long-distance dispersal of deep-sea hydrothermal vent shrimps
Deep-sea hydrothermal vents and methane seeps are extreme environments that have a high concentration of hydrogen sulphide. However, abundant unique invertebrates including shrimps of the family Bresiliidae have been found in such environments. The bresiliid shrimps are believed to have radiated in the Miocene (less than 20 Myr); however, the period when and the mechanisms by which they dispersed across the hydrothermal vents and cold seeps in oceans worldwide have not been clarified. In the present study, we collected the deep-sea blind shrimp Alvinocaris longirostris from the hydrothermal vent site in the Okinawa Trough and carried out the first investigation of the 18S rRNA gene of a bresiliid shrimp. The phylogenetic analysis revealed that the bresiliid shrimp is situated at an intermediate lineage within the infraorder Caridea and shows monophyly with palaemonid shrimps, which live in shallow sea and freshwater. Furthermore, the mitochondrial cytochrome oxidase I (COI) gene sequences were analysed to determine the phylogenetic relationship with known bresiliid shrimps. A. longirostris of the Okinawa Trough had two haplotypes of the COI gene, one of which was identical to the Alvinocaris sp. of the cold seeps in Sagami Bay. These results indicate that a long-distance dispersal of A. longirostris occurred possibly within the last 100 000 years