  We analyze the conformational properties of polymer macromolecules in
solutions in presence of extended structural obstacles of (fractal) dimension
$\varepsilon_d$ causing the anisotropy of environment. Applying the
pruned-enriched Rosenbluth method (PERM), we obtain numerical estimates for
scaling exponents and universal shape parameters of polymers in such
environments for a wide range $0<\varepsilon_d<2$ in space dimension $d=3$. An
analytical description of the model is developed within the des Cloizeaux
direct polymer renormalization scheme. Both numerical and analytical studies
qualitatively confirm the existence of two characteristic length scales of
polymer chain in directions parallel and perpendicular to the extended defects.
