Threads in PyQt4

I want to create threads in PyQt4 $for normal use GUI$.

Make thread class:

class solveThread$QtCore.QThread$:
        def run$self$:
              <what do you want doing>

Check for use thread with same name and kill it if yes:

        if $hasattr(self,'s1'$):
            del$self.s1$
        self.s1=solveThread


If I want terminate thread by button, I use variable self.isExit=0 in infinite while loop $I don't use Thread.terminate($ ). And I use refresh GUI each 5-10 sec (otherwise my GIU is freezing).