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Ultrastructure and mineral composition of urinary calculi from horses.
Am J Vet Res. 1994 Oct; 55(10):1357-67.AJ

Abstract

Urinary calculi from 17 horses with urolithiasis were examined to study their mineral content and ultrastructure. Among the analytic methods used were X-ray diffractometry, scanning electron microscopy, and electron microprobe analysis. The calculi initially were observed by use of a stereoscopic dissecting microscope and generally were found to have nodular surfaces surrounding a banded or granular-to-chalky interior. Observation by scanning electron microscopy revealed an intricate pattern of irregularly concentric, fine bands and spherules. These had a round, finely banded, globular texture formed by precipitation of ultrafine-grained radiating crystals. The original pore spaces (ie, between spherules, between bands and spherules, or between crystal generations) could be observed as primary porosity. Precipitation and dissolution of these urinary calculi were observed to be spontaneous processes, which can occur simultaneously within an individual calculus. Another prominent feature of the ultrastructure was secondary porosity (spontaneous dissolution) which, in its incipient stages, appeared to be site-selective (ie, some bands appeared to be more susceptible to development of pinpoint porosity). Textures indicative of dissolution were observed not only on the calculus surface, but within the calculus interior as well. Areas that had more advanced stages of dissolution, resulting in increased secondary porosity, also were observed. All 17 samples of the study were found to be composed of calcium carbonate in the form of the mineral calcite, although minor quantities of 2 other polymorphs of calcium carbonate, minerals vaterite and aragonite, also were encountered. Vaterite was observed in 5 of the samples, whereas aragonite was found in 1 sample. Strontium and sulfur were observed as trace elements in 3 of the calculi, whereas magnesium was present in all calculi. Magnesium was observed to substitute for calcium within the calcite crystal lattice in larger quantities than those of strontium or sulfur. Magnesium K alpha X-ray dot maps generated by use of an electron microprobe analyzer indicated that the distribution pattern of magnesium appeared to closely follow layer-by-layer growth of the calculus. Magnesium distribution also appeared to be related to porosity development. In samples where preferential dissolution was observed, the more porous areas had higher magnesium content. Quantitative chemical analyses, using the electron microprobe analyzer, confirmed these observations. Association of the magnesium distribution pattern to the primary growth texture of the calculus indicated that magnesium content of the calculus varied during the formation process. This also indicated that changes in urine chemical analytes may be reflected in composition of the calculi formed.(

ABSTRACT

TRUNCATED AT 400 WORDS)

Authors+Show Affiliations

Department of Medicine, School of Veterinary Medicine, University of California, Davis 95616.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

7998690

Citation

Neumann, R D., et al. "Ultrastructure and Mineral Composition of Urinary Calculi From Horses." American Journal of Veterinary Research, vol. 55, no. 10, 1994, pp. 1357-67.
Neumann RD, Ruby AL, Ling GV, et al. Ultrastructure and mineral composition of urinary calculi from horses. Am J Vet Res. 1994;55(10):1357-67.
Neumann, R. D., Ruby, A. L., Ling, G. V., Schiffman, P., & Johnson, D. L. (1994). Ultrastructure and mineral composition of urinary calculi from horses. American Journal of Veterinary Research, 55(10), 1357-67.
Neumann RD, et al. Ultrastructure and Mineral Composition of Urinary Calculi From Horses. Am J Vet Res. 1994;55(10):1357-67. PubMed PMID: 7998690.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ultrastructure and mineral composition of urinary calculi from horses. AU - Neumann,R D, AU - Ruby,A L, AU - Ling,G V, AU - Schiffman,P, AU - Johnson,D L, PY - 1994/10/1/pubmed PY - 1994/10/1/medline PY - 1994/10/1/entrez SP - 1357 EP - 67 JF - American journal of veterinary research JO - Am. J. Vet. Res. VL - 55 IS - 10 N2 - Urinary calculi from 17 horses with urolithiasis were examined to study their mineral content and ultrastructure. Among the analytic methods used were X-ray diffractometry, scanning electron microscopy, and electron microprobe analysis. The calculi initially were observed by use of a stereoscopic dissecting microscope and generally were found to have nodular surfaces surrounding a banded or granular-to-chalky interior. Observation by scanning electron microscopy revealed an intricate pattern of irregularly concentric, fine bands and spherules. These had a round, finely banded, globular texture formed by precipitation of ultrafine-grained radiating crystals. The original pore spaces (ie, between spherules, between bands and spherules, or between crystal generations) could be observed as primary porosity. Precipitation and dissolution of these urinary calculi were observed to be spontaneous processes, which can occur simultaneously within an individual calculus. Another prominent feature of the ultrastructure was secondary porosity (spontaneous dissolution) which, in its incipient stages, appeared to be site-selective (ie, some bands appeared to be more susceptible to development of pinpoint porosity). Textures indicative of dissolution were observed not only on the calculus surface, but within the calculus interior as well. Areas that had more advanced stages of dissolution, resulting in increased secondary porosity, also were observed. All 17 samples of the study were found to be composed of calcium carbonate in the form of the mineral calcite, although minor quantities of 2 other polymorphs of calcium carbonate, minerals vaterite and aragonite, also were encountered. Vaterite was observed in 5 of the samples, whereas aragonite was found in 1 sample. Strontium and sulfur were observed as trace elements in 3 of the calculi, whereas magnesium was present in all calculi. Magnesium was observed to substitute for calcium within the calcite crystal lattice in larger quantities than those of strontium or sulfur. Magnesium K alpha X-ray dot maps generated by use of an electron microprobe analyzer indicated that the distribution pattern of magnesium appeared to closely follow layer-by-layer growth of the calculus. Magnesium distribution also appeared to be related to porosity development. In samples where preferential dissolution was observed, the more porous areas had higher magnesium content. Quantitative chemical analyses, using the electron microprobe analyzer, confirmed these observations. Association of the magnesium distribution pattern to the primary growth texture of the calculus indicated that magnesium content of the calculus varied during the formation process. This also indicated that changes in urine chemical analytes may be reflected in composition of the calculi formed.(ABSTRACT TRUNCATED AT 400 WORDS) SN - 0002-9645 UR - https://www.unboundmedicine.com/medline/citation/7998690/Ultrastructure_and_mineral_composition_of_urinary_calculi_from_horses_ L2 - https://medlineplus.gov/minerals.html DB - PRIME DP - Unbound Medicine ER -