I have struggled with this: whether there really is true altruism. (Is that redundant?) I don't think you can help others without feeling good, so there is really no selfless action. Perhaps selflessness comes when you can be totally unattached to self while performing actions, but this isn't easy. Your survival instinct holds on to the concept of self for dear life! Literally! So, I came to the conclusion that since at some level, everything and everyone is connected, even a selfish act is altruistic. If I benefit me, I benefit all. But that's really an out.
I have come to the conclusion that the answer to every question is mindfulness and the way to mindfulness is meditation. Through mindfulness, it's ironic, you realize that you have no mind, that mind is nothing, has no substance. So from the place of no mind, I believe you can perform a self-less act.
Of course, if you are studying to be a doctor, and you lose your mind, where will you be?
Perhaps then you will have to study psychiatry.