From Pope cancels appearance:
"Pope John Paul II has cancelled plans to preside over a Holy Mass scheduled for next week in St Peter's Basilica, the Vatican announced on Thursday.
In a statement, the Vatican press office said Tuesday's remembrance Mass in honour of two of his predecessors, Paul VI and John Paul I, would be officiated by Cardinal Joseph Ratzinger, one of the pope's closest aides.
No reason for the change of plan was given by the Vatican, which had published the pope's schedule leading up to Christmas just a few days ago.
Concern among Vatican experts is constantly high over the health of Pope John Paul, who is 84 and has been suffering rom Parkinson's disease and other age-related ailments for some time. "