Isoamylase abnormalities in cystic fibrosis [letter].

The article by Townes et al. provides confirmation of our initial studies 
with reference to the isoamylase patterns of serum, duodenal fluid, and 
urine in patients with cystic fibrosis (CF). However, the impression given 
by Townes et al. in their article is that their data 
are the first demonstration of isoamylase abnormalities in cystic fibrosis. I 
wish to point out that out previous work published 2 years 
earlier and not referenced by Townes et al. demonstrated that CF 
patients had decreased amounts of pancreatic isoamylase in their serum and 
urine and that the duodenal aspirates in CF patients contained both 
salivary and pancreatic amylase. We concluded, as eluded to by Townes 
et al., that salivary amylase in the duodenal fluid was probably 
secondary to the intubation procedure. 