Analysis of Thiodiphenol in Rat Urine as a Biomarker of Exposure to Temephos
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThis is a study about the development of a liquid chromatography method to assess the evolution in time of metabolites generated from a pesticide in male rats. This study is useful in the broader context of toxicity assessment of such pesticides in humans. I found the study well designed and suitable for this journal's topic.
Nevertheless, there is room for improvement so here are my comments on a line-by-line basis:
Lines 35, 174, 249 etc. (check the entire paper): the simbol for litre should be L (capitalised)
Line 74: avoid using contracted forms such as "don't" in scientific writing; better use "do not"
Line 79: "information is very limited" is probably the message you intended to convey , not as written "lack of information ... is very limited"
Line 101: Is 97% the purity of temephos before or after purification following the protocol of Verdin-Betancourt et al. ? This is not made clear as currently written in the text.
Line 123: the saline solution should have been mentioned also in subsection 2.1
Line 125: Indicate centrifuge type and manufacturer (with place and country). Do this for all major equipment.
Line 130: sodium acetate must be added to section 2.1 also with all relevant details
Line 137: same for sodium sulfate
Line 138: Include N2 gas also in subsection 2.1
Line 169: I find the value "3.29" rather odd. Why such value? Typically 3 or 3.3 or 3.33 are multipliers used in LOD calculation.
Table 1 shows results of some measurements and should therefore be part of the Results section of the manuscript, not Materials and Methods. Include units at the top of each column for all parameters reported (e.g. %)
Lines 184-185: State a bit more about the specific statistical tests you performed using this software in order to interpret results, make comparisons etc.
Lines 189-193: Such comments are of an interpretative nature and would belong better to the Discussion section rather than the Results section
Line 208: ethyl acetate must also be mentioned in section 2.1
Table 2: rate constants shown in the first columns cannot have negative values. Please carefully check your data or your calculations!
A separate Conclusions section would be very useful to readers of this paper. Include the summary you already wrote at the end of the Discussion, but add also some comments about the limitations of the work herein and how these could be addressed in the future (i.e. future work).
Author Response
Dear Reviewer:
We sincerely thank you for the comments on our manuscript. We have carefully considered the helpful questions, suggestions, and comments, and we have revised our manuscript accordingly. We hope our responses are satisfactory.
Reviewer 1
Lines 34, 174, 249 etc. (check the entire paper): the symbol for liter should be L (capitalised).
Response: Thank you for your pointing this out. We have changed “l” to “L” to the symbol for liter throughout the manuscript.
Line 74: avoid using contracted forms such as “don’t” in the scientific writing; better use #do not”
Response: we appreciate your comment and have changed the contracted forms throughout the manuscript, page 2, line 73.
Line 79: “information is very limited” is probably the message you intended to convey, not as written “lack of information… is very limited
Response: We agree and appreciate your comment. Therefore, we removed “lack of” to clarify the sense of the phrase. Page 3, line78.
Line 101: Is 97% the purity of temephos before or after purification following the protocol of Verdin-Betancourt et al. ? This is not made clear as currently written in the text.
Response: we agree with this comment. In this sense, we add the symbol “>” to clarify the purity. The acceptable minimum purity of each lot purified was 97% based on the area peaks present in the chromatogram. Page 3, line100.
Line 123: the saline solution should have been mentioned also in subsection 2.1
Line 130: sodium acetate must be added to section 2.1 also with all relevant details
Line 137: same for sodium sulfate
Line 138: Include N2 gas also in subsection 2.1
Line 208: ethyl acetate must also be mentioned in section 2.1
Response: thank you for your comments about reagents used in this study. Section 2.1, Reagents, includes information about the saline solution, sodium sulfate, sodium acetate, and nitrogen gas. Page 3, lines 107-112.
Line 125: Indicate centrifuge type and manufacturer (with place and country). Do this for all major equipment.
Response: we agree with this comment. Information about centrifuge type and manufacturer was included. Page 4, line 132.
Line 169: I find the value”3.29” rather odd. Why such value) Typically 3 or 3.3 or 3.33 are multipliers used in LOD calculation.
Response: Thank you very much for your observation. We agree with you. We corrected this value (3.3) in the text, and calculations were determined using this value based on the new reference [18. Shrivastava, A., Gupta, V.B. (2011). Methods for the determination of limit of detection and limit of quantitation of the analytical methods. Chron. Young Sci. 2, 21-25. doi: 10.4103/2229-5186.79345], which was changed instead of the former. Page 5, line 179.
Table 1 shows results of some measurements and should therefore be part of the Results section of the manuscript, not Material and Methods. Include units at the top of each column for all parameters reported (e.g. %)
Response: we appreciate your comment on it, and we agree with you; therefore, the description of the Table 1 was included in the Results section, page 5, lines 208-209. The former mention was removed from the 2.6 section, page 5, line 178. Additional information about the Results of Quality Control was included. Page 5, lines 202-209.
Lines 184-185: State a bit more about the specific statistical tests you performed using this software in order to interpret results, make comparisons etc.
Response: Thank you for your comments. We included more information about how statistical analysis was performed to assess differences in the different experimental conditions evaluated for processing samples. Page 5, lines 193-195.
Lines 189-193: Such comments are of an interpretative nature and would belong better to the Discussion section rather than the Results section
Response: We appreciate your comments; for this reason, they were also included in the Discussion section. Page 9, lines 301-303.
Table 2: rate constants shown in the first columns cannot have negative values. Please carefully check your data or your calculations!
Response: Thank you for your comment. We apologize for this mistake; we omitted to erase the negative sign.
A separate Conclusions section would be very useful to readers of this paper. Include the summary you already wrote at the end of the Discussion, but also some about the limitations of the work herein and how these could be addressed in the future (i.e. future work).
Response: Thank you for your comments. We agree with your proposals. Therefore, we included a Conclusions section after the Discussion section, in which we also added some limitations of this study and how we could address to apply findings and improve the reach using other analytical systems in future studies. Page 11, lines 386-392.
My co-authors and I thank you for the time and effort you took to consider this manuscript for publication in the Journal of Xenobiotics.
Yours sincerely,
Dr. Adolfo Sierra-Santoyo
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript is of high-quality in an essential topic of biomonitoring metabolites of pesticides. I have some comments that if addressed the manuscritp will be improved, and in the end accepted.
1) The authors should present more validation data regarding the analytical method. Specifically, in Table 1 the number of replicates should be presented (n=..) (not only in the text i mean). In the same context, the Table should be moved to the results section. In page 4, line 172, I suggest replacing reference 18, and insert a more appropriate one. LOD and LOQs of the method is not clear from which samples are caclulated. This point should be clarified. I also recommend the authors refer to a guideline for bioanalytical method validation and provide more data concerning the precision of the method and stability of the study. These are typical in such methods, and based on the quality of the work, I suppose the authors have such data.
2) In discussion, lines 261-262 please revise the detection of SIDP metabolite. Since there is overlap of peaks is difficult to distinguish without mass spectrometry instrumentation. Also a comment on potential (future) use of mass spectrometry in this direction should be provided.
3) Minor comments: Page 1, line 39, "using treated drinking water" is not clear. Please revise. Page 3, line 76 is "non-target". In page 9, line 292, please check the term "probation" and make it more clear.
Comments on the Quality of English LanguageEnglish is fine in general. An editing English comment is on the consistent use of capital L, for mL (not ml).
Author Response
Dear Reviewer:
We sincerely thank you for the comments on our manuscript. We have carefully considered helpful questions, suggestions, and comments and revised our manuscript accordingly. We hope our responses are satisfactory.
1) The authors should present more validation data regarding the analytical method. Specifically, in Table 1 the number of replicates should be presented (n=..) (not only in the text i mean. In the same context, the Table should be moved to the results section. In page 4, line 172, I suggest replacing reference 18, and insert a more appropiate one. LOD and LOQs of the method is not clear from which simples are caclulated. This point should be clarified. I also recommend the authors refer to a guideline for bioanalytical method validation and provide more data concerning the precisión of the method and stability of the study. These are typical in such methods, and based on the quality of the work, I suppose the authors have such data.
Response: thank you for your comments. More information on validation in the Results section was included on page 5, lines 201-209. In the caption of Table 1, we included the number of urine samples used in this assay and the 2.6 section, page 5, lines 175-176, line 184. The description of the Table 1 was included in the Results section, page 5, lines 208-209. The former mention was removed from the 2.6 section, page 5, formerly line 178.
The reference 18, on page 4, line 172 was substituted by a more appropriate one (Shrivastava, A., Gupta, V.B. (2011). Methods for the determination of limit of detection and limit of quantitation of the analytical methods. Chron. Young Sci. 2, 21-25. doi: 10.4103/2229-5186.79345).
Calculations of how LOD and LOQ were determined were included and clarified based on reference 18 (Shrivastava and Gupta, 2011). Page 5, lines 176-180. Validation of the analytical method was performed on the basis of “Huber, L. (2001). Validation of Analytical Methods: Review and Strategy. Pp 1-22. LabCompliance. www.labcompliance.com”. Previous results on validation of our analytical methods in different matrices have been published, i.e., references [3, 16], among others.
2) In discusión, lines 261-262 please revise the detection o SIDP metabolite. Since there is overlap of peaks is difficult to distinguish without mass spectrometry instrumentation. Also a comment on potential (future) use of mass spectrometry in this direction should be provided.
Response: We appreciate your comment and agree with you. We included a few remarks in the Discussion section, page 9, lines 292-293, page 11, lines 390-391.
3) Minor comments: Page 1, line 39, “using treated drinking water” is not clear. Please revise. Page 3, line 76 is “non-target”. In page 9, line 292, please check the term “probation” and make it more clear.
Response: Thank you for your comments. We have edited it to clarify the idea.
English is fine in general. An editing English comment is on the consistent use of capital L, for mL (not ml).
Response: We appreciate your comment. We have changed “l” to “L” to the symbol for liter throughout the manuscript.
My co-authors and I thank you for the time and effort you took to consider this manuscript for publication in the Journal of Xenobiotics.
Yours sincerely,
Dr. Adolfo Sierra-Santoyo
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper provides valuable insights into the urinary excretion kinetics of Temephos metabolites, but needs stronger connections to human health implications. The methodology, especially regarding enzyme selection, requires more justification, and data analysis needs clarity on model fitting (The pharmacokinetic model chosen for the analysis of metabolite elimination (two-compartment model) is appropriate, but the fitting process and the assumptions behind it should be better explained. Further, provide sensitivity analysis or alternative model outcomes to strengthen the reliability of your findings). The figures need better resolution, and ethical considerations around animal use should be expanded. Figure Quality: Figures 2, 4, and 5 lack sufficient resolution and are difficult to interpret. Additionally, the legends do not fully explain the significance of the data points. I suggest revising the figures for clarity and providing more descriptive captions that guide the reader through the key insights. Additionally, language refinement and updates to outdated references are recommended. The plagiarism rate of 40% is too high and must be reduced to comply with journal standards. Please revise accordingly.
Comments on the Quality of English LanguageMust be improved
Author Response
Dear Reviewer:
We sincerely thank you for the comments on our manuscript. We have carefully considered helpful questions, suggestions, and comments and revised our manuscript accordingly. We hope our responses are satisfactory.
The paper provides valuable insights into the urinary excretion kinetics of Temephos metabolites, but needs stronger connections to human health implications. The methodology, especially regarding enzyme selection, requires more justification, and data analysis needs clarify on model fitting (The pharmacokinetic model chosen for the analysis of metabolite elimination (two-compartment model) is appropiate, but the fitting process and the assumptions behind it should be better explained. Further, provide sensitivity analysis or alternative model outcomes to strengten the reliability of your findings). The figures need better resolution, and ethical considerations around animal use should be expanded. Figure Quality: Figures 2, 4, and 5 lack sufficient resolution and are difficult to interpret. Additionally, the legend do not fully explain the significance of data points. I suggest revising the figures for clarity and providing more descriptive captions that guide the reader through the key insights. Additionally, languaje refinament and updates to outdated references are recommended. The plagiarism rate of 40% is too high and must be reduced to comply with journal standards. Please revise accordingly.
Response: Thank you for your comments, and we share your opinion. However, in spite, temephos has been used for more than 5 decades to control different vectors of diseases such as dengue, Zika, and chikungunya, among others, no information exists on the association between temephos exposure and human health implications. To date, it is impossible to determine human exposure because there is no biomarker of exposure to this pesticide, and its toxicokinetics and toxicological properties in humans are unknown. Therefore, the primary goal of this study was to determine the urinary metabolic profile and propose a biomarker of temephos exposure with the potential to be applied in humans, which will help in the risk assessment for this pesticide. Comments in this respect are included in the Introduction and Discussion sections.
The information on how temephos metabolites are excreted in urine is very limited. We used β-glucuronidase/sulfatase to detect more potential metabolites in urine, avoiding using acidic or alkaline conditions for hydrolysis of conjugated metabolites. In the Discussion section, we included information to justify using this enzyme, page 10, lines 326-331.
Rate of excretion plots are very useful in the determination of elimination constants (Kelim), they were estimated from the slope of the curves in the log-linear Rate of excretion (ΔU/Δt) versus mid-point time plots and were calculated by linear regression as described in 2.7 section and the Discussion section, page 9, lines 301-304.
We appreciate your comment and agree with you in providing sensitivity analysis or alternative model outcomes to strengthen the reliability of your findings. In response, we included a few remarks in the Discussion section, page 9, lines 292-293; page 11, lines 390-392.
We included some remarks about animal use in the 2.2 and 2.3 sections.
We apologize that Figs. 2, 4, and 5 lack sufficient resolution in the copy sent to you. The resolution of the figures submitted is 300 dpi. More information was included in the captions of figures for a better interpretation.
The bibliography around toxicological information on temephos is limited. We are continuously revising the bibliography related to this pesticide. We have included the most important available references to support this study.
The last version of the manuscript was verified for plagiarism rate, excluding references, cites, and phrases lower than 10 words, exhibiting a result lower than 25% using iThenticate and excluding references of 6% using Grammarly software.
My co-authors and I thank you for the time and effort you took to consider this manuscript for publication in the Journal of Xenobiotics.
Yours sincerely,
Dr. Adolfo Sierra-Santoyo
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsAll the suggested comments have been addressed.
