[1] Inst Clin & Expt Med, Dept Hepatogastroenterol, Prague 14622 4, Czech Republic
[2] Masaryk Univ, Dept Hepatogastroenterol, Fac Med, Brno, Czech Republic
[3] Charles Univ Prague, Dept Internal Med 4, Fac Med 1, Prague, Czech Republic
[4] Palacky Univ, Dept Internal Med 2, Fac Med & Dent, CR-77147 Olomouc, Czech Republic
[5] Charles Univ Prague, Dept Gastroenterol & Hepatol, Fac Med, Hradec Kralove, Czech Republic
[6] Charles Univ Prague, Dept Hepatogastroenterol, Fac Med, Plzen, Czech Republic
[7] Inst Clin & Expt Med, Dept Stat, Prague 14622 4, Czech Republic