  We obtain an estimate of Voiculescu's (modified) free entropy dimension for
generators of a ${II}_1$-factor $\mc{M}$ with a subfactor $\mc{N}$ containing
an abelian subalgebra $\mc{A}$ of finite multiplicity. It implies in particular
that the interpolated free group subfactors of finite Jones index do not have
abelian subalgebras of finite multiplicity or Cartan subalgebras.
