Recently published research

This feature presents a personal selection of some significant articles that were listed in Medline from March to May 2000. Readers need to be aware that abstracts written by authors themselves may sometimes give an positive 'slant' to the paper which is not strictly based on the findings. Where an author's address is available we include it so that readers who wish for a reprint can request it directly. Alternatively, a number of journals now publish on the worldwide web and some articles may be downloaded in pdf versions. Copyright 2000 Harcourt Publishers Ltd.