Review for 10.1186/1471-230X-13-91 (2013)

Reviewer's report
Title:Rectal Biopsies Procedure in Cystic Fibrosis: Technical Aspects and
Patients Perspective for Clinical Trials Feasibility
Version: 1Date:25 November 2012
Reviewer: John Clancy
Reviewer's report:
Major compulsory revisions
• Overall question Methods section) - How was the CF diagnosis derived in the
CF patients? Was it known in advance, or was the biopsy used for diagnosis? If it
was part of their diagnosis, then there is a positive risk of bias regarding
tolerance, as the information from the biopsy would have diagnostic implications
(and thus there were factors independent of the biopsy influencing the perception
of procedure tolerance).
• Overall question (should be a table in the supplementary section) - What was
the genotype of the CF patients?
• Overall question (Results) - How did CFTR responses differ based on biopsy
forceps and bowel preparation, particularly in the non-CF group? If this
addressed, the authors will need to provide information regarding the nature of
functional CFTR detection.
• Methods, page 9, under statistics - How was blinded scoring data handled for
correlative analyses? Were scores averaged, or independently assessed with the
outcome measures of interest?
• Results, Pages 10 and 11 - Was there correlation between friability and integrity
scores and presence of CFTR response in Ussing chambers?
Minor essential revisions
• Introduction, Page 4, first paragraph – life shortening (not ’severe’) disease
• Introduction, Page 5, third paragraph – use of the term ‘(pre)-clinical’ is not clear
in the manuscript. Inclusion of human subjects constitutes clinical testing,
regardless if it is an interventional trial or not.
• Introduction, Page 5, third paragraph – ‘Our results demonstrate that best tissue
viability for Ussing chamber measurements results after bowel preparation with
isotonic solution (NaCl 0.9%) and usage of jumbo (vs standard size) biopsy
forceps allowing collection of larger specimens without tissue integrity (?). It’s not
clear what is being stated.
• Methods, Page 6, under Rectal biopsy procedure - (2-4 mm Ø) - please define
Ø
• Methods, Page 8, under Biochemical assays: immunoblotting and
immunofluorescence – how were tissues processed for WB?
• Methods, Page 9, under Questionnaire used for patients’ assessment of the
rectal biopsy procedure – ‘divided into 4 age groups’ (repeated), namely (yrs):
0-9 (n=21); 10-9 (should be 10-19) (n=33); 20-29 (n=7); #30 (n=14).’
• Methods, Page 9, same paragraph – Had all of the subjects undergone blood
draws and sweat chloride testing for comparison with rectal biopsy?
• Results, Page 10, under Bowel preparation and biopsy forceps – How does the
glycerol preparation (and the others) compare with go-lytely (a commonly used
bowel preparative regimen)?
• Results, Page 10, third paragraph – ‘Regarding bleeding and mucus, their
presence/abundance are not (were not ) influenced by bowel preparation nor
biopsy forceps.’
• Results, Page 11, under Histological and macroscopic evaluation of rectal
tissues and biochemical analysis – did histology reveal diffs based on jumbo vs
standard biopsy forceps?
• Figure 3B – consider including higher magnification inset to clarify surface
localized CFTR antigen vs cytoplasmic. Also, how many biopsies were assessed
for IF? How often did wtCFTR have a surface membrane staining pattern, and
how often did F508del/F508del have only a cytoplasmic staining pattern? Was
there a relationship between the detection of CFTR at the plasma membrane and
CFTR activity?
• Results, Page 12, under Patient safety and comfort with overall procedure –
recommend to report the symptoms in the results section, and provide potential
interpretations in the discussion section.
• Results Page 13, under Patient safety and comfort with overall procedure –Was
there a difference in tolerance based on CF vs non-CF (as presumably the CF
patients were having this performed strictly for research purposes)?
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
Nothing to declare