BACKGROUND Mechanical unloading of the heart results in atrophic remodeling. In skeletal muscle, atrophy is associated with inactivation of the mammalian target of rapamycin (mTOR) pathway and upregulation of critical components of the ubiquitin proteosome proteolytic (UPP) pathway. The hypothesis is that mechanical unloading of the mammalian heart has differential effects on pathways of protei...

The effects of mechanical unloading and reloading on the properties of rat soleus muscle fibers were investigated in male Wistar Hannover rats. Satellite cells in the fibers of control rats were distributed evenly throughout the fiber length. After 16 days of hindlimb unloading, the number of satellite cells in the central, but not the proximal or distal, region of the fiber was decreased. The ...

The diaphragm, the main muscle of inspiration, is constantly subjected to mechanical loading. One of the very few occasions during which diaphragm loading is arrested is during controlled mechanical ventilation in the intensive care unit. Recent animal studies indicate that the diaphragm is extremely sensitive to unloading, causing rapid muscle fiber atrophy: unloading-induced diaphragm atrophy...

Insufficient stress response and elevated oxidative can contribute to skeletal muscle atrophy during mechanical unloading (e.g., spaceflight bedrest). Perturbations in heat shock proteins HSP70), antioxidant enzymes, sarcolemmal neuronal nitric oxidase synthase (nNOS) have been linked unloading-induced atrophy. We recently discovered that the NADPH oxidase-2 complex (Nox2) is unloading, downstr...

As human beings venture into space in the 21st century, they will be confronted with a "hypodynamic" and thus hostile environment for the bone homeostasis, that could potentially compromise their mobility in general and skeletal strength in particular after landing. From this point of view, space flight studies are especially interesting and intriguing models for scientists. Space studies, howe...

1543 it before publication.' We have recently become aware of a published thesis by Margot M. Bartelings8 at the University of Leiden that discusses cardiac development and uses the new terminology of Pexieder et a17 as well as the classic nomenclature. Although we are in general satisfied with this suggested nomenclature,7 we believe it would benefit from clarification on two points. For our o...

Our aim was to determine the effects of pre- and/or postconditioning with mild hyperbaric oxygen (1.25 atmospheric pressure, 36% oxygen for 3 h/day) on the properties of the soleus muscle that was atrophied by hindlimb suspension-induced unloading. Twelve groups of 8-week-old rats were housed under normobaric conditions (1 atmospheric pressure, 20.9% oxygen) or exposed to mild hyperbaric oxygen...

[Purpose] The purpose of this study was to determine whether collagen fibers cause a difference in a contracture resulting from a combination of joint fixation and hindlimb unloading as compared to joint fixation only. [Subjects and Methods] The subjects of this study were 21 female Wistar rats divided into 4 groups as follows: Control Group (CON, n=7); Joint Fixation Group (JF, n=7), Hindlimb ...