at four days of growth fusion of myoblasts ( as expressed by the percent of all muscle nuclei that are located in myotubes ) is 57 +/- 2 % in 5 % oxygen , 68 +/- 1 % in 20 % oxygen , and 78 +/- 2 % in 40 % oxygen ( p less than 0.001 ) .
C0026845
muscle
C1704336
myotubes