Polyamines protect against radiation-induced oxidative stress.

Astronauts and cosmonauts are exposed to a wide variety of different hazards while in space that include radiation, which presents one of the most critical barriers to long-term missions. A major deleterious effect directly associated with ionizing radiation is the production of reactive oxygen species (ROS) such as peroxides and hydroxyl radicals. The free radicals generated by ultraviolet (UV) or ionizing radiation can attack cellular lipids, proteins and DNA.

Three-dimensional growth of endothelial cells in the microgravity-based rotating wall vessel bioreactor.

We characterized bovine aortic endothelial cells (BAEC) continuously cultured in the rotating wall vessel (RWV) bioreactor for up to 30 d. Cultures grew as large tissue-like aggregates (containing 20 or more beads) after 30 d. These cultures appeared to be growing in multilayers around the aggregates, where single beads were covered with confluent BAEC, which displayed the typical endothelial cell (EC) morphology.

Muscle-specific effects of hindlimb suspension and clenbuterol in mature male rats.

Anabolic agents are useful tools for probing the mechanisms by which muscle fibers perceive and respond to disuse. beta(2)-Adrenergic agonists exert protective, and/or reparative, effects on atrophying muscle tissue. The effects of one such agent, clenbuterol (Cb), were examined on muscle mass, total protein content, and myofibrillar protein content in selected hindlimb muscles [adductor longus (ADL), extensor digitorum longus (EDL), plantaris (PLAN), soleus (SOL)] of mature male rats, under different loading conditions.

Distribution and muscle-sparing effects of clenbuterol in hindlimb-suspended rats.

Based on their anabolic properties in skeletal muscles, beta-adrenergic agonists are of interest as potential countermeasures to microgravity-induced skeletal muscle atrophy. The levels of clenbuterol (Cb), a beta(2)-adrenergic agonist, in both plasma and skeletal muscle were higher in hindlimb-suspended rats than in their nonsuspended Cb-treated controls. Cb treatment was shown to help maintain the body weight in suspended rats, while reducing the amount of mesenteric fat.

Beta-agonist-induced alterations in organ weights and protein content: comparison of racemic clenbuterol and its enantiomers.

Clenbuterol is a relatively selective beta2-adrenergic partial agonist that has bronchodilator activity. This drug has been investigated as a potential countermeasure to microgravity- or disuse-induced skeletal muscle atrophy because of presumed anabolic effects. The purpose of this study was to: 1) analyze the anabolic effect of clenbuterol's (-)-R and (+)-S enantiomers (0.