I was running into the same problem. This is the solution that worked for me on http://www.mycollegesandcareers.com
which we're running on an Ubuntu server.
redirectMatch 301 ^/careers[\s]/(.*)$ http://www.mycollegesandcareers.com/careers/$1
the whole [\s] is regular expression for any whitespace. It's the only thing that would work for me. I couldn't get any of the suggested stuff above to work.
Hope this helps someone else that is in the same boat as I was.