Detection of cystic fibrosis protein by electrofocusing.

Detection of cystic fibrosis protein (CFP) using out method involves rather exacting 
requirements for the collection of serum samples and their subsequent analysis 
by electrofocusing. Minor variations in the methods described for sample collection 
and storage may cause degradation and loss of CFP and this 
by itself could lead to erroneous results since many CF samples 
would appear to be CFP negative, making it impossible to observe 
a consistent difference between a group of CF samples and normal 
control samples by electrofocusing. From the results presented by Thomas et 
al. and Figure 1 of the letter by Smith et al., 
it is obvious that neither group has reproduced the protein handling 
patterns presented in either of our previous reports. The pH gradients 
are not the same, the location of the sample pads relative 
to the anode are not the same, and the protein banding 
patterns are totally different. We question the validity of the techniques 
used, claims of having reproduced our method for detecting CFP, or 
supposed improvements designed to enhance the detection of CFP. 