Train-of-four ratio with administration of rocuronium. Train-of-four ratio was significantly smaller in the moderate and severe myasthenia gravis (MG) groups than in the sham group at control and was significantly different among the three groups with 25% inhibitory concentration (IC25) for attenuation of first evoked isometric twitch tension and IC50 of rocuronium. n = 6 in each group. *P < 0.05 versus sham group, **P < 0.01 versus sham group, ††P < 0.01 versus the moderate MG group. Data were analyzed by using two-way repeated-measures ANOVA with the Tukey test.