HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ascione, R. Articles by Angelini, M.D. G. D. Search for Related Content PubMed Articles by Ascione, R. Articles by Angelini, M.D. G. D. Related Collections Related Article

Ann Thorac Surg 2000;69:978-979
© 2000 The Society of Thoracic Surgeons

---

Correspondence

Reply

^a Bristol Heart Institute, Bristol Royal Infirmary, Bristol, England BS2 8HW, England, USA

To the Editor

We thank Dr Tang and colleagues for their constructive comments on our work [1]. Our study was intended to examine the influence of cardiopulmonary bypass and off-pump techniques on both glomerular and tubular renal function.

N-acetyle glucosaminidase (NAG) is present in high activity in the tubular lysosomes; thus, its presence in the urine is a direct sign of tubular damage consisting of structural cellular changes. NAG release in the urine is not affected by dysfunction of other organs [2]. On the contrary, the retinol binding protein (RBP) is produced by the liver, released in the blood, filtered by the glomerulae, and reabsorbed with a saturable process by the proximal tubules. As such, the amount of RBP in the urine is an indirect sign of tubular dysfunction and may also represent glomeral dysfunction and liver injury. We would therefore urge potential investigators who wish to use RBP not to forget to carefully investigate the preoperative liver function and glomerular filtration, because this may alter the assessment of renal function. The lack of control of preoperative liver and glomerular function was indeed one of the main limitations of the study of Bernard and associates [3] and Tang and associates [4].

With regard to the use of nephrotoxic agents that may have affected renal tubular function, we can confirm that none of the patients in the study received nonsteroid, antiinflammatory drugs, and a low dose of dopamine was required in 6 and 3 patients in the on- and off-pump groups, respectively, in the postoperative period, in accordance with our intensive care unit protocol to improve hemodynamic conditions.

References

1. Ascione R., Lloyd C.T., Underwood M.J., Gomes W.J., Angelini G.D. On-pump versus off-pump coronary revascularisation. Ann Thorac Surg 1999;68:493-498.[Abstract/Free Full Text]
2. Price R.G. Measurement of N-acetyl-ß-glucosaminidase and its isoenzymes in urine. Methods and clinical applications. Eur J Clin Chem Clin Biochem 1992;30:693-705.[Medline]
3. Bernard A.M., Vyskocil A.A., Mahieu P., Lauwerys R.R. Assessment of urinary retinol-binding protein as an index of proximal tubular injury. Clin Chem 1987;33:775-779.[Abstract/Free Full Text]
4. Tang A.T.M., El-Gamel A., Keevil B., Yonan N., Deiraniya A.K. The effect of ‘renal-dose’ dopamine on renal tubular function following cardiac surgery. Eur J Cardiothoracic Surg 1999;15:717-722.[Abstract/Free Full Text]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Ascione, R. Articles by Angelini, M.D. G. D. Search for Related Content PubMed Articles by Ascione, R. Articles by Angelini, M.D. G. D. Related Collections Related Article