  We prove uniform resolvent estimates for an abstract operator given by a
dissipative perturbation of a self-adjoint operator in the sense of forms. For
this we adapt the commutators method of Mourre. We also obtain the limiting
absorption principle and uniform estimates for the derivatives of the
resolvent. This abstract work is motivated by the Schr{\"o}dinger and wave
equations on a wave guide with dissipation at the boundary.
