[1] Univ Pavia, I-27100 Pavia, Italy
[2] Univ Hamburg, Childrens Hosp, Dept Paediat Haematol & Oncol, Hamburg, Germany
[3] Univ Brescia, Pediat Clin, Ist Med Mol Angelo Nocivelli, I-25121 Brescia, Italy
[4] Univ Padua, Pediat Clin, I-35100 Padua, Italy
[5] Univ Milano Bicocca, Osped San Gerardo, Pediat Clin, Monza, Italy
[6] Osped Pausilipon, Naples, Italy
[7] Univ Ulm, Sect Expt Anaesthesiol, D-89069 Ulm, Germany
[8] IRCCS Policlin San Matteo, Biometry & Clin Epidemiol Serv, Pavia, Italy
[9] IRCCS Policlin San Matteo, Pediat Clin, Pavia, Italy