  It is argued that $N\sim Z$ nuclei with $90\leq A\leq100$ can be interpreted
in terms of aligned neutron--proton pairs with angular momentum $J=2j$ and
isospin T=0. Based on this observation, a version of the interacting boson
model is formulated in terms of isoscalar high-spin bosons. To illustrate its
possible use, the model is applied to the $21^+$ isomer in $^{94}$Ag.
