  This reports our recent studies on changes in properties of heavy hadrons
containing at least a charm or a bottom quark in nuclear matter, and that the
results for the $\Lambda^+_c$ and $\Lambda_b$ hypernuclei are studied
quantitatively. Comparisons are made with the results for the $\Lambda$
hypernuclei studied previously in the same approach. It is shown that although
the scalar and vector potentials for the $\Lambda$, $\Lambda_c^+$ and
$\Lambda_b$ in the hypernuclei multiplet with the same baryon numbers are quite
similar, the wave functions obtained, e.g., for $1s_{1/2}$ state, are very
different. The $\Lambda^+_c$ probability density distribution in
$^{209}_{\Lambda^+_c}$Pb is much more pushed away from the center than that for
the $\Lambda$ in $^{209}_\Lambda$Pb due to the Coulomb force. On the contrary,
the $\Lambda_b$ probability density distributions in $\Lambda_b$ hypernuclei
are much larger near the origin than those for the $\Lambda$ in the $\Lambda$
hypernuclei due to its heavy mass. A possibility of $B^-$ nuclear bound
(atomic) states is also briefly discussed.
