Reviewer's report
Title:Total and caspace-cleaved cytokeratine 18 in chronic cholecystitis: A
prospective study
Version: 1Date:19 December 2007
Reviewer: Stig Linder
Reviewer's report:
Simopoulos et al., "Total and caspase-cleaved cytokeratin 18 in chronic
cholecystitis: A prospective study".
This is a rather preliminary but potentially interesting study on detection of
caspase-cleaved CK18 products in bile samples.
The levels of caspase-cleaved CK18 in the bile of both groups of cholecystitis
patients is high (5 - 10-fold) compared to the levels observed in serum from the
same patients (and from normal individuals as reported in the literature). This
finding may indicate elevated apoptosis in the epithelial cells of the gall bladder.
It is difficult to interpret the finding since the levels of caspase-cleaved CK18 in
bile fluid from normal subjects is unknown. If it is not possible to obtain bile
from normal individuals, the study is therefore very not conclusive.
How were measurements in bile performed? The M30/M65 ELISA assays have
not previously been used for bile samples and assay performance, CK18
solubilite etc (and, in addition, dilution and spike recovery characteristics) are not
known. Were any assay validation studies performed (efficiency of detection of
exogenously added assay standard to bile fluid, dilution linearity of bile
samples)?
The M30 antibody was used for immunohistochemistry (Fig. 1). The experiment
is refered to as "intense expression of CK18 was presented in the epithelial cells
of the mucosa of the gall bladder". This is misleading - the authors must mean to
say "cells staining positive for caspase-cleaved CK18 were present...". However,
I do not see the staining pattern expected (occasional apoptotic cells staining
positive using the M30 antibody) in the figure (all cells can not be positive -
apoptosis is a transient phenomenon and the epithelium would not be maintained
if this was so). Positive cells should be indicated with arrows. Again, there is no
comparison to gall bladder from subjects not suffering from cholecystitis (which I
understand may be difficult to obtain).
This study would be interesting if it is possible to perform IHC on normal gall
bladder epithelium, or obtain gall samples from subjects not suffering from
cholecystitis. If this is not possible, the study appears to be of liminted value.
Minor issues:
1. There are some spelling errors; caspace (caspase), cytokeratine (cytokeratin).
2. Page 3: "liberating neo-epitopes inaccessible to thr caspase cleavage site"
(what does this mean?)
What next?: Unable to decide on acceptance or rejection until the authors have
responded to the major compulsory revisions
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Not suitable for publication unless extensively edited
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I have a financial interest in the company that produces the ELISA kits used for
this study (Peviva AB).
Reviewer's report
Title:Total and caspace-cleaved cytokeratine 18 in chronic cholecystitis: A
prospective study
Version: 1Date:19 December 2007
Reviewer: Stig Linder
Reviewer's report:
Simopoulos et al., "Total and caspase-cleaved cytokeratin 18 in chronic
cholecystitis: A prospective study".
This is a rather preliminary but potentially interesting study on detection of
caspase-cleaved CK18 products in bile samples.
The levels of caspase-cleaved CK18 in the bile of both groups of cholecystitis
patients is high (5 - 10-fold) compared to the levels observed in serum from the
same patients (and from normal individuals as reported in the literature). This
finding may indicate elevated apoptosis in the epithelial cells of the gall bladder.
It is difficult to interpret the finding since the levels of caspase-cleaved CK18 in
bile fluid from normal subjects is unknown. If it is not possible to obtain bile
from normal individuals, the study is therefore very not conclusive.
How were measurements in bile performed? The M30/M65 ELISA assays have
not previously been used for bile samples and assay performance, CK18
solubilite etc (and, in addition, dilution and spike recovery characteristics) are not
known. Were any assay validation studies performed (efficiency of detection of
exogenously added assay standard to bile fluid, dilution linearity of bile
samples)?
The M30 antibody was used for immunohistochemistry (Fig. 1). The experiment
is refered to as "intense expression of CK18 was presented in the epithelial cells
of the mucosa of the gall bladder". This is misleading - the authors must mean to
say "cells staining positive for caspase-cleaved CK18 were present...". However,
I do not see the staining pattern expected (occasional apoptotic cells staining
positive using the M30 antibody) in the figure (all cells can not be positive -
apoptosis is a transient phenomenon and the epithelium would not be maintained
if this was so). Positive cells should be indicated with arrows. Again, there is no
comparison to gall bladder from subjects not suffering from cholecystitis (which I
understand may be difficult to obtain).
This study would be interesting if it is possible to perform IHC on normal gall
bladder epithelium, or obtain gall samples from subjects not suffering from
cholecystitis. If this is not possible, the study appears to be of liminted value.
Minor issues:
1. There are some spelling errors; caspace (caspase), cytokeratine (cytokeratin).
2. Page 3: "liberating neo-epitopes inaccessible to thr caspase cleavage site"
(what does this mean?)
What next?: Unable to decide on acceptance or rejection until the authors have
responded to the major compulsory revisions
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Not suitable for publication unless extensively edited
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I have a financial interest in the company that produces the ELISA kits used for
this study (Peviva AB).
Please review this paper.
user
Reviewer's report
Title:Total and caspace-cleaved cytokeratine 18 in chronic cholecystitis: A
prospective study
Version: 1Date:19 December 2007
Reviewer: Stig Linder
Reviewer's report:
Simopoulos et al., "Total and caspase-cleaved cytokeratin 18 in chronic
cholecystitis: A prospective study".
This is a rather preliminary but potentially interesting study on detection of
caspase-cleaved CK18 products in bile samples.
The levels of caspase-cleaved CK18 in the bile of both groups of cholecystitis
patients is high (5 - 10-fold) compared to the levels observed in serum from the
same patients (and from normal individuals as reported in the literature). This
finding may indicate elevated apoptosis in the epithelial cells of the gall bladder.
It is difficult to interpret the finding since the levels of caspase-cleaved CK18 in
bile fluid from normal subjects is unknown. If it is not possible to obtain bile
from normal individuals, the study is therefore very not conclusive.
How were measurements in bile performed? The M30/M65 ELISA assays have
not previously been used for bile samples and assay performance, CK18
solubilite etc (and, in addition, dilution and spike recovery characteristics) are not
known. Were any assay validation studies performed (efficiency of detection of
exogenously added assay standard to bile fluid, dilution linearity of bile
samples)?
The M30 antibody was used for immunohistochemistry (Fig. 1). The experiment
is refered to as "intense expression of CK18 was presented in the epithelial cells
of the mucosa of the gall bladder". This is misleading - the authors must mean to
say "cells staining positive for caspase-cleaved CK18 were present...". However,
I do not see the staining pattern expected (occasional apoptotic cells staining
positive using the M30 antibody) in the figure (all cells can not be positive -
apoptosis is a transient phenomenon and the epithelium would not be maintained
if this was so). Positive cells should be indicated with arrows. Again, there is no
comparison to gall bladder from subjects not suffering from cholecystitis (which I
understand may be difficult to obtain).
This study would be interesting if it is possible to perform IHC on normal gall
bladder epithelium, or obtain gall samples from subjects not suffering from
cholecystitis. If this is not possible, the study appears to be of liminted value.
Minor issues:
1. There are some spelling errors; caspace (caspase), cytokeratine (cytokeratin).
2. Page 3: "liberating neo-epitopes inaccessible to thr caspase cleavage site"
(what does this mean?)
What next?: Unable to decide on acceptance or rejection until the authors have
responded to the major compulsory revisions
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Not suitable for publication unless extensively edited
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I have a financial interest in the company that produces the ELISA kits used for
this study (Peviva AB).
assistant