We give two short proof of a
weak version of the theorem of Laudenbach, Poenaru [3]. Also we show that an
embedded S1× S2 in S4 bounds a copy of B2× S2. Finally we establish
that if W is a smooth 4-manifold with ∂W = #nS1× S2 and W is built
from #n−1B2× S2 by attaching a 2-handle, then W is homeomorphic to
#nB2× S2.