Is There a Time of Day Difference in Treatments?

Research has shown that bone marrow transplants at certain times of the day are more likely to have a good outcome. But there hasn't been enough research for us to know whether that's going to be borne out as a general principle or not. The vast majority of research in this area has either been done in cells, in a petri dish or in mice. So it's difficult to know how you would approach this as a general question. Can we beforehand work out what the best time of day to try it is?