Researchers looking for a way to make night shifts more bearable for residents in emergency medicine, did a randomised crossover trial of melatonin as an aid to daytime sleeping (Academic Emergency Medicine 2000;7:955-8). It didn't work. Melatonin had no more effect than placebo on sleep duration, sleep efficiency, mood disturbance, and night time sleepiness. This is the fourth trial of melatonin for people working shifts in emergency departments. All had negative or equivocal results.

Medical students and junior doctors rate their mentors differently, according to a study in Academic Medicine (2000;75:843-5). Students from Baylor College of Medicine in Texas ranked teaching skills highest. Residents in family medicine were more impressed by good supervisors who allowed them to practise their skills and gave feedback. Both groups rated commitment to teaching highly, but only residents ranked teachers by the depth of their knowledge.

It's hard to imagine anything more ironic than British American Tobacco criticising the World Health Organization for its record on tobacco control, except perhaps the suggestion, made in a press release last week, that the tobacco giant could do it better. This display of brass neck is made all the more breathtaking by the fact that covert operations inside the WHO by moles paid by British American Tobacco …