Mechanism of anti-HIV action of masked alaninyl 2′,3′-dideoxy-2′,3′-didehydrothymidine 5′-monophosphate derivatives: J. Balzarini1, H. Egberink2, K. Hartmann3, A. Karlsson4, C.-F. Perno5, D. Cahard6, L. Naesens1, H. Thormar7, E. De Clercq1 and C. McGuigan6 1Rega Institute for Medical Research, K.U.Leuven, Leuven, Belgium; 2Institute of Virology, Veterinary Faculty, Utrecht, The Netherlands; 3Medizinische Tierklinik, München, Germany; 4Karolinska Institute, Stockholm, Sweden; 5University of Rome “Tor Vergata”, Rome, Italy; 6Welsh School of Pharmacy, University of Wales, Cardiff, United Kingdom; 7Institute of Biology, University of Iceland, Reykjavik, Iceland