  We derive the constraints imposed on neutrino masses and mixing angles by
performing a combined analysis of the data from the Los Alamos and the other
terrestrial neutrino oscillation experiments with the assumption of the
flavor-mixing solutions to the solar neutrino problem. In a three-flavor mixing
scheme which ignores the possibility of sterile neutrinos, we obtain severe
constraints on the pattern of masses and flavor mixing of neutrinos. For
example, we show that in the standard Kobayashi-Maskawa type mixing matrix
$s_{13}^2 \lsim 10^{-2}$ independent of the choice of the solar neutrino
solutions. The constraint from the double $\beta$ decay is also discussed.
