Neutrophil Gelatinase-Associated Lipocalin (NGAL) in Peritoneal Dialytic Effluent: Preliminary Results on the Comparison between Two Different Methods in Patients with and without Peritonitis

Round 1

Reviewer 1 Report

The manuscript describes Neutrophil gelatinase-associated lipocalin (NGAL) in peritoneal dialytic effluent: comparison between two different methods in patients with and without peritonitis. Objectives are very clear but the main concern is the sample size. In a comparative study, total sample size of 30 would not be sufficient at all. This is also reflected by concluding remarks accepting that this is a preliminary study. So I would rather like to suggest to continue this study by recruiting more cases and controls and publish at a later stage.

In addition, 

1. Introduction: needs complete revision focusing on the background problem and objectives in case of a resubmission.
2. Methodology: No sample size. Better structure compared to Introduction and Results.  
3. Results: complete restructuring is needed. This section also includes the information from the previous methodology section.  

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

In this interesting study, the authors aimed to investigate the role of Neutrophil gelatinase-associated lipocalin levels in peritoneal dialytic effluents in patients with and without peritonitis.

The findings of this research paper are promising and can contribute significantly to the knowledge of efficient markers of peritonitis and dialytic performance. The results of this paper are in line with previous research by the same authors, in particular with the study “The Role of NGAL in Peritoneal Dialysis Effluent in Early Diagnosis of Peritonitis: Case-Control Study in Peritoneal Dialysis Patients”. I suggest you mention this research and highlight the points in common and differences.
I support the publication of this paper after a few modifications.

I suggest you add the conclusion paragraph to the paper.

Some minor English corrections in grammar and form should be provided. For example, line 45 “It belongs to the lipocalin superfamily, a group of proteins that implicated in the defence of the organism against pathogens.” Should be modified in “It belongs to the lipocalin superfamily, a group of proteins implicated in the organism's defense against pathogens”.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The current manuscript is method-based quantitative approach using samples from patients with peritonitis and study conducted under clinical setting.  Grazia Maria Virzi et al trying to establish the rapid semi-quantitative colorimetric method to diagnose the inflammatory marker NGAL and the quantification was performed based on dip-stick (NGALds) method compared to well established or standard biochemical turbidometric immunoassay using the test kit manufactured by BioPorto Diagnostics. The NGAL was quantified in peritoneal dialytic effluent of peritoneal dialysis patients with peritonitis. Based on the clinical data and results, authors concluded that the NGAL can be quantified accurately and rapidly with dip-stick approach compared to standard immunoassay. One of major limitation of current study is number of patients pooled and conducted and patients may have any other co-morbidities which can potentially affect the inflammatory condition of peritonitis. However, authors need to address the several concerns, before the current manuscript can be accepted for publication in peer reviewed journal Applied Sciences in MDPI.

Comments:

In the introduction, need to explain about what is peritonitis and clinical symptoms, diagnosis and significance etc.

In Figure 1, Number of patient samples used in represented graphs? Need to mention clearly in Figure legend. Is these samples collected from male or female patients or together?

In Figure 2, number of patient samples were used to compared the both NGAL quantification method? Need to mention clearly in Figure legend.

Is there any gender differences can impact on the inflammation in patients with peritonitis? Need to explain in the discussion.

Author Response

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Reviewer 4 Report

Dear authors,

Thank you for submitting your article “Neutrophil gelatinase-associated lipocalin in peritoneal dialytic effluent: comparison between two different methods in patients with and without peritonitis” to our journal.

The article describes   the usefulness of NGALds in the peritonitis diagnosis. Manuscript is well structured; Material and Methods section is clear and Results are clearly presented. However, I would like to make some suggestions to improve the article.

Conclusion Section is optional but it could improve manuscript:

Please, add the Institutional Review Board Statement and approval number for studies involving humans or animals. Please add “The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of NAME OF INSTITUTE (protocol code XXX and date of approval).”

Please, add Data Availability Statement Section.

Please, rewrite References List according to Author´s Guidelines.

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The main concern was the small sample size of the study. I understand that it may take several months to increase the sample size. However, due to the novel nature of the study, I too agree with authors responses to my concerns. But they should include a paragraph on "limitations of the study" in the discussion. They should remove the sentences in the conclusion on this regard and simplify the conclusions. I also suggest to highlight this "preliminary" concept  to be reflected in the title.     

Author Response

Author's Reply to the Review Report (Reviewer 1)

Round2

The main concern was the small sample size of the study. I understand that it may take several months to increase the sample size. However, due to the novel nature of the study, I too agree with authors responses to my concerns. But they should include a paragraph on "limitations of the study" in the discussion. They should remove the sentences in the conclusion on this regard and simplify the conclusions.

As suggested by reviewer, we inserted the “limitations of the study" in a specific paragraph. Furthermore, we shortened conclusion and rimodulated it.

I also suggest to highlight this "preliminary" concept  to be reflected in the title. 

As suggested by reviewer, we inserted preliminary concept in the title

Thank you for giving us the opportunity to revise and resubmit our manuscript.

We thank the reviewers for their insightful comments. We believe the manuscript has been improved with the suggested changes. We hope the Editors now find our revised manuscript acceptable for publication.

Author Response File: Author Response.docx