[1] UNIV LA SAPIENZA,PEDIAT CLIN,I-00100 ROMA,ITALY
[2] UNIV NEWCASTLE TYNE,ROYAL VICTORIA INFIRM,DEPT CHILD HLTH CLIN BIOCHEM,NEWCASTLE TYNE NE2 H44,ENGLAND
[3] UNIV BERN,INSELSPITAL,DEPT CLIN CHEM,CH-3010 BERN,SWITZERLAND
[4] UNIV NOTTINGHAM,SCH MED,DEPT BIOCHEM,NOTTINGHAM NG7 2RD,ENGLAND