see this book under the link, Chapter 5, Are conflicts of interest hazardous to our health?
it gives some very clear examples where and how things have gone wrong. involving high level politics.
the problem is systemic and persistent.
what is unfortunate is that this book is already from 2005, that we are now almost 10 years later and that nothing much seems to have changed...http://www.amazon.com/s/ref=nb_sb_noss? ... sity%20Inc