tokens: Higher plasma ammonium levels and more rapid onset of hyperammonemia were seen in 18 patients with bacterial infections ( p = 0 . 003 and 0 . 0006 , respectively ) and in nine patients receiving high daily doses ( 2600 or 1800 mg / m2 ) of 5 - FU ( p = 0 . 0001 and < 0 . 0001 , respectively ) .