The typographical corrections below were made to the article on the date noted. These changes have been incorporated in the article and the details are documented here.

18 August 2000:

In Figure 8, in the first sentence of the caption:

...before 0 and after 15 and 60 min treatment (15', 60') with 1 mM LAT-A.

was changed to:

...before (0) and after 15 and 60 min treatment (15', 60') with 1 mM LAT-A.

In Figure 9, in the first sentence of the caption:

...before (0) and after 15 and 60 min treatment (15', 60') with LAT-A,....

was changed to:

...before (0) and after 15 and 60 min treatment (15', 60') with 1 mM LAT-A,....

In Figure 10, in the first sentence of the caption:

...before (0) and after 15 and 60 min treatment (15', 60') with LAT-A.

was changed to:

...before (0) and after 15 and 60 min treatment (15', 60') with 1 mM LAT-A.