IRAM (Granada) 
Observatoire de Paris (France) 
upper
limits are below the solar mass for the molecular content of these
objects, down to 0.07 M
for NGC 5272. Since mass loss from AGB stars
and post-turnoff stars should provide up to 100 M
of
intracluster gas between two disk crossings, we conclude that
the gas must have been removed through ram-pressure stripping in a hot
gaseous halo, as suggested by recent [OIII] and
X-ray observations. For some clusters, however, the present hot gas
density in the halo is not sufficient for efficient ram-pressure stripping.