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Urolithiasis

, Volume 41, Issue 6, pp 481–486 | Cite as

Stent encrustation in feline and human artificial urine: does the low molecular weight composition account for the difference?

  • M. Shafat
  • K. Rajakumar
  • H. Syme
  • N. BuchholzEmail author
  • M. M. Knight
Original Paper

Abstract

Anecdotal evidence suggests that the rate of encrustation on JJ stents placed in domesticated cats appears to be decreased as compared to humans. Our study tests the hypothesis that this may be due to specific differences in the chemical composition of human and feline urine. Artificial human and feline urine solutions were used in an in vitro encrustation model where an 80 % stent encrustation could be expected after 7 weeks of incubation. Scanning electron microscopy (SEM) was used to analyse crystal morphology. Energy dispersive X-ray spectrometry (EDS) was used to assess composition weight. The percentage of surface coverage of encrustation on the respective stents was quantified using image J Java plug-in software. No significant difference was observed between both solutions with regard to quality and quantity of stent encrustation. Crystals were formed in both solutions as a mixture of Ca-dihydrate and Ca-monohydrate. The study shows that there is no significant difference in the rate of encrustations on JJ stents incubated in artificial feline or human urine. This suggests that a possible difference in stent encrustation between cats and humans is due to factors other than the inorganic biochemical composition of the urines alone. Keeping in mind a true species difference, analysis of urinary macromolecules and proteins will be the logical next step.

Keywords

Stent Encrustation Artificial urine Feline urine Human urine Calcium Oxalate Crystallization 

Notes

Conflict of interest

The authors declare no conflict of interest.

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Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • M. Shafat
    • 1
  • K. Rajakumar
    • 2
  • H. Syme
    • 3
  • N. Buchholz
    • 4
    Email author
  • M. M. Knight
    • 1
  1. 1.Institute of Bioengineering, School of Engineering and Materials ScienceQueen Mary University of LondonLondonUK
  2. 2.Barts and The London Medical SchoolLondonUK
  3. 3.Royal College of Veterinary MedicineHertfordshireUK
  4. 4.Department of UrologyBarts Health NHS TrustLondonUK

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