Study of Cystine Urinary Calculi in Dogs Elena Escolar, Juana Bellanato and Manuel Rodriquez
comme constituants associes de more uroliths were studied by infrared l'oxalate calcique (mono et/ou dihy- spectroscopy. Several selected samThe composition and structure of 48 drate), du phosphate ammoniacoma- ples were also examined by means of canine cystine urinary stones were gnesien hexahydrate (struvite), de scanning electron microscopy (SEM) determined by infrared spectroscopy, l'hydrogenophosphate de calcium and electron dispersive X-ray analysis scanning electron microscopy and dihydrate (brushite) et des urates (EDAX). In order to detect minor electron dispersive X-ray analysis. The complexes (d'ammonium, d'ammo- phosphates whose infrared bands infrared analysis showed that about nium potassique et/ou d'ammonium could be overlapped by those of the 45% of the specimens were composed riche en potassium). L'etude par overwhelming cystine, 18 samples (a of pure cystine. The remainder also spectroscopie infrarouge de quelques whole stone or part of it) were contained calcium oxalate (mono echantillons calcines a 6200 C et 7500 C calcinated and the residues analyzed and/or dihydrate), magnesium am- a aussi permis de relever l'existence de by infrared spectroscopy and EDAX. monium phosphate hexadydrate phosphate calcique (apatite), ce (struvite), calcium hydrogen phos- constituant etant difficile 'a reconnaiMATERIALS AND METHODS phate dihydrate (brushite) and com- tre dans les spectres des echantillons plex urates (ammonium, ammonium originaux du a la faible concentration The 48 samples studied were vesical potassium and/or potassium enriched en phosphate et a la superposition des ammoniumn urate). The infrared study bandes. L'examen par microscopie a and/ or urethral calculi surgically of several samples heated at 6200 C balayage et l'analyse de l'energie removed from male dogs of different and 7500 C revealed the presence of dispersee par rayons X de quelques ages and breed (Tables I and II), either apatitic calcium phosphate. This echantillons selectionnes ont permis in private veterinary clinics or in the compound was difficult to detect in de completer les resultats obtenus par Department of Surgery of the Veterithe spectrum of the original samples spectroscopie infrarouge. nary Faculty of the University of due to the small proportion of Madrid. Infrared spectra of selected areas phosphate contained in the calculi and to band overlapping. The examination taken from half of the stone were INTRODUCTION of a series of selected samples by recorded on a Perkin-Elmer 599B means of scanning electron microThe incidence of canine cystine spectrophotometer, using the KBr scopy and energy dispersive X-ray urolithiasis is high in Spain. In a recent pellet technique. The other half of the analysis complemented the infrared study of 171 urinary calculi carried out stone was used in many cases for in our laboratory, cystine occurred in examination under the electron results. 26% of the cases and it was frequently microscope and/ or for calcination. accompanied by one or two additional The morphology of calculi was RESUME compounds (1). On the contrary, it has observed in a Philips SEM-500 been described in the literature that scanning electron microscope La composition et la structure de cystine calculi contain only pure equipped with EDAX analyzer. From eighteen stones of sufficient quarante-huit calculs urinaires de cystine (2,3). This conclusion may be cystine provenant de chiens ont ete due to inadequate analysis, since by size, we took half for calcination at 620 determinees a l'aide de differentes detailed examination other compo- and 7500C. At these relatively high techniques: spectrophotometrie infra- nents can be detected, as has been temperatures cystine decomposes, rouge, microscopie a balayage et reported in recent papers dealing with leaving only the accompanying minanalyse de l'energie dispersee par both human and canine urolithiasis eral components, which in the case of phosphates have undergone several rayons X. L'etude par spectroscopie (4-6). In the present work, 48 canine transformations already described in infrarouge a de montre que presque de 45% des echantillons presentaient cystine samples derived from one or the literature (7,8).
ABSTRACT
Departamento de Patologia Animal II. Patologia General y Medica. Facultad de Veterinaria de la Universidad Complutense de Madrid, 28040, Madrid, Spain (Escolar, Rodriguez) and Instituto de Optica. CSIC. Serrano, 121. 28006 Madrid, Spain (Bellanato). Submitted February 15, 1990.
Can J Vet Res 1991; 55: 67-70
67
2.5
TABLE I. Age distribution of 48 dogs with cystine uroliths
3.0
4.0
5.0
--
25
16
40 .L
/,I ~P
~j~-)H,
-~
c
12 10 9 12 4
12
9.0
80-
Number of cases
Age in years 0-2 2-4 4-6 6-8 8 Not known
7.0
6.0
l4
E 40_ c
v
,iII
3000
4000
2000
1600
800
1200
400
cm-1
Fig. 1. Infrared spectrum of a cystine calculus showing calcium oxalate.
RESULTS The age and breed of the affected dogs are presented in Tables I and II. INFRARED STUDY
The infrared analysis revealed that about 45% of the stones were composed of nearly pure cystine (> 97%). Calcium oxalate was detected in two cases in concentrations between 3 and 25%, depending on the zone examined. This compound is easily recognized by the presence of the characteristic band at about 1320 cm-' in the infrared spectrum of the cystine calculus (Fig. 1). Struvite was detected in two cases in a proportion lower than 5% of the total weight. It was recognized by the infrared bands at 1010 and 572 cm-'. Brushite (infrared bands at 3545, 3495, 1140, 1065, 990 and 875 cm-' among others) was found in one case in a proportion varying from 5 to 40%, also depending on the zone and stone analyzed. Ammonium urate and/or complex urates containing ammonium and other cations were found in two specimens. As usual, both samples consisted of several calculi of different structure. In some stones (yellow), TABLE II. Breed distribution of 48 dogs with cystine uroliths Breed Basset Hound Boxer Bulldog Collie Dachshund Fox Terrier German Shepherd Golden Retriever Labrador Retriever Miniature Pinscher Pekingese Pointer Rottweiler Setter (unspecified) Mongrels Not known
68
a
band at 1320 cm-' (l), characteristic of
peared linked by "film-like" organic matrix. Brushite was clearly differentiated from cystine in the calculus examined by SEM, both compounds appearing as firmly connected layers (Figs. 5a, Sb). In calculi containing calcium oxalate, well delimited zones of this compound were seen between zones of cystine (Figs. 6a, 6b). Finally, two mixed calculi of cystine and urates were also found (Fig. 7). As in previously studied canine urate calculi (4,9), the urates found in cystine stones consisted mainly of ammonium urate and complex urates containing ammonium and potassium. In several zones, potassium content was very high, this result suggesting the presence of potassium urate (Figs. 8 and 9). Moreover, calcium was also detected in urate
ammonium urate was mainly concentrated in the central area (see Fig. 7). In other stones (grey), the ammonium urate was heterogeneously distributed, reaching values from 8 to nearly 100%. The infrared study of 18 calcinated samples showed in ten cases the existence of calcium phosphate ( < 3%), mainly apatite, which was only suspected through the examination of the spectrum of the original calculus. This calcium apatite (nonstoichiometric hydroxyapatite) was clearly recognized because after stone calcination at 7500 C for 2 h, the spectrum of the residue (Fig. 2) corresponded to that of 13-calcium orthophosphate. SEM/EDAX STUDY
Under SEM examination, nearly perfect hexagonal cystine prisms appeared in two cases (Fig. 3), areas. although hexagonal compact cystine crystals were most commonly obDISCUSSION served. Moreover, spherulites of apatitic calcium phosphate were The incidence of cystine stones in detected in three of the samples examined, either over cystine crystals or canine urolithiasis found by us in a intermeshed with them (Fig. 4). In previous survey in dogs in the Madrid some zones, spherulites of pseudoa- area (26%) is in agreement with the morphous calcium phosphate ap- values given by other European
Number of cases 2.5
3.0
4.0
5.0
6.C
7.0
9.0 I,I
I
I.
I,
12 I
16 .1,1,1.1
1
25
40e
2 '
80-
2 3
2
1
3
3 3
C
v
4000
3000
2000
1600
1200
800
400
cm-1
2 19 3
Fig. 2. Infrared spectrum of the calcination residue of a cystine calculus containing calcium apatite (heated at 7500 C for 2 h).
Fig. 5a. Scanning electron micrograph (X320) of a calculus containing cystine and brushite. Left side: cystine; right side: brushite (Smaller bars = 10 ,um).
authors (10,11,12). However, these values are higher than those reported in the American literature, which oscilate between 1.8 and 6.8% (2,5, 13,14). Furthermore, the cystine incidence in dogs is also much higher than in humans, in which values around 1% are given (6). In relation to sex, we have only found cystine calculi in male dogs, although some authors claim to have also found them in females (5,15,16). Concerning age, although in previous reports it was stated that cystine urolithiasis tends to occur in young animals (10,15,17), the results of the present study show a wide age range. No breed seems to be especially prone to cystine urolithiasis with the
exception of mongrels, which comprise a very large proportion of the dog population. With respect to associated compounds, Ling and Ruby (5) reported the presence of apatite, brushite and uric acid/urates in canine cystine calculi. Concerning uric acid, it should be noted that these authors do not describe the techniques used for the analysis. Hesse et al (4), in a study of 160 canine cystine uroliths using infrared spectroscopy, SEM and EDAX techniques, identified calcium apatite in the majority of the stones. Moreover, they found struvite in four cases and brushite in one case. In the present work, calcium apatite was the mineral most frequently associated with cystine (at least in 55% of the samples), although, with an exception, in small proportions, not surpassing 3% of the total weight. We attribute the presence of apatite in cystine stones to an increase of the
Fig. 4. Scanning electron micrograph (X640) of a cystine calculus, showing small spherules of calcium apatite (Smaller bars = 10 ,um).
Fig. 6a. Scanning electron micrograph (X320) of the central zone of a cystine stone, showing strata of calcium oxalate (Smaller bars = 10 Mm).
Fig. 3. Scanning electron micrograph (X5000) of a cystine hexagonal prism, found in a cystine calculus (Bars = 1 ,um).
Fig. 5b. Sulphur distribution of the area shown in Fig. 5a (EDAX).
normal pH of the urine as a consequence of changes of diet. This fact may favor apatite deposits between
preformed cystine crystals. We have detected brushite only in cystine case, which consisted of several stones. The concentration of brushite depended on the zone and stone analyzed. Concentrations of brushite as high as 40% of the total weight were found. This rare phase combination of cystine and brushite is also mentioned by Hesse et al (4). Urates found in cystine stones are similar in composition and structure to other previously studied calculi mainly composed by urates (4,9). The two samples found in the present work showed, besides ammonium urate and probably potassium urate, a high proportion (at least 80%) of one
ammonium-potassium complex urates. ACKNOWLEDGMENTS The authors wish to thank Dr. J.A. Medina, Department of Geology and
Fig. 6b. Calcium distribution of the area shown in Fig. 6a (EDAX).
69
|~ ~ 'J.
----------------
-
4?,l r
Fig. 7. Scanning electron micrograph (X20) of a mixed calculus composed of cystine (outer region) and urates (central area) (Smaller bars 100 Jm).
Fig. 8. Scanning electron micrograph (X2500) of the central zone of Fig. 7 (EDAX: potassium) (Smaller bars = 1 Mm).
Fig. 9. Scanning electron micrograph (X1250) of a zone of Fig. 7 showing bundles of ammonium potassium complex urates (EDAX: potassium) together with larger cystine crystals (EDAX: sulphur) (Bars = 10 ,um).
Geochemistry, Facultad de Ciencias, Universidad Autonoma, Madrid, for
Phasen und Gefugeanalyse von Zystinsteinen. In: Gasser G, Vahlensieck W, eds. Pathogenese und Klinik der Harnsteine XIII. Darmstadt: Steinkopff, 1988: 203-207. HIDALGO A, BELLANATO J, GONZALEZ-DIAZ PF, SANTOS M. Los fosfatos de los calculos del aparato urinario. In: Problemas Actuales de Urologia. Barcelona: Salvat Editores SA, 1977: 205-211. GONZALEZ-DIAZ PF, GARCIARAMOS JV, SANTOS M. Composition of apatites in human urinary calculi. Calcif Tissue Int 1979; 28: 215-225. BELLANTO J, ESCOLAR E. Estudio comparativo de urolitos de uratos de origen humano y animal por espectroscopia infrarroja, microscopia electronica de barrido y EDAX. Opt Pur Apl 1988; 21: 217-225. CLARK WT. The distribution of canine urinary calculi and their recurrence following treatment. J Small Anim Pract 1974; 15: 437-444. DE SCHEPPER J, VAN DER STOCK J. Incidence and distribution pattern of canine urinary calculi in Belgium. Vlaams Diergeneesk Tijdschr 1980; 49: 178-186.
12. WEAVER AD. Canine urolithiasis: incidence, chemical composition and outcome of 100 cases. J Small Anim Pract 1970; 11: 93-107. 13. FINCO DR, ROSIN E, JOHNSON KH. Canine urolithiasis: A review of 133 clinical cases and 23 necropsy cases. J Am Vet Med Assoc 1970; 157: 1225-1228. 14. OSBORNE CA, CLINTON CW, DAVENPORT MP. Analyzing the mineral composition of uroliths from dogs, cats, horses, cattle, sheep, goats, and pigs. Vet Med 1989; 84: 750-764. 15. BROWN NO, PARKS JL, GREENE RW. Canine urolithiasis: retrospective analysis of 438 cases. J Am Vet Med Assoc 1977; 170: 414-418. 16. STOICHEW II. Urolithiasis in dogs from villages in Bulgaria. J Comp Pathol 1980; 90: 619-623. 17. BOVEE KC. Canine cystine urolithiasis. Vet Clin North Am (Small Anim Pract) 1986; 16: 211-215. 18. OSBORNE CA, O'BRIEN TD, GHOBRIAL HK, MEIHAK L, STEVENS JB.
his contribution in taking the scanning electron micrographs. 7.
REFERENCES 1. ESCOLAR E, BELLANATO J, MEDINA JA. Structure and composition of canine urinary calculi. Res Vet Sci (in press). 2. BOVEE KC, McGUIRE T. Qualitative and quantitative analysis of uroliths in dogs: definitive determination of chemical type. J Am Vet Med Assoc 1984; 185: 983-987. 3. DI BARTOLA SP, CHEW DJ. Canine urolithiasis. Compend Contin Educ Pract Vet 1985; 3: 201-210. 4. HESSE A, SANDERS G, LEUSMANN DB. Analysis of canine urinary stoncs using infrared spectroscopy and scanning electron microscopy. Scan Electron Microsc 1986; IV: 1705-1712. 5. LING GV, RUBY AL. Canine uroliths: analysis of data derived from 183 specimens. Vet Clin North Am (Small Anim Pract) 1986; 16: 303-316. 6. LEUSMANN DB, KLEINHANS G, POHL J, HOLZKNECHT A. Kombinierte
70
8.
9.
10.
11.
Crystalluria. Observations, interpretations and misinterpretations. Vet Clin North Am (Small Anim Pract) 1986; 16: 45-65.
comme constituants associes de more uroliths were studied by infrared l'oxalate calcique (mono et/ou dihy- spectroscopy. Several selected samThe composition and structure of 48 drate), du phosphate ammoniacoma- ples were also examined by means of canine cystine urinary stones were gnesien hexahydrate (struvite), de scanning electron microscopy (SEM) determined by infrared spectroscopy, l'hydrogenophosphate de calcium and electron dispersive X-ray analysis scanning electron microscopy and dihydrate (brushite) et des urates (EDAX). In order to detect minor electron dispersive X-ray analysis. The complexes (d'ammonium, d'ammo- phosphates whose infrared bands infrared analysis showed that about nium potassique et/ou d'ammonium could be overlapped by those of the 45% of the specimens were composed riche en potassium). L'etude par overwhelming cystine, 18 samples (a of pure cystine. The remainder also spectroscopie infrarouge de quelques whole stone or part of it) were contained calcium oxalate (mono echantillons calcines a 6200 C et 7500 C calcinated and the residues analyzed and/or dihydrate), magnesium am- a aussi permis de relever l'existence de by infrared spectroscopy and EDAX. monium phosphate hexadydrate phosphate calcique (apatite), ce (struvite), calcium hydrogen phos- constituant etant difficile 'a reconnaiMATERIALS AND METHODS phate dihydrate (brushite) and com- tre dans les spectres des echantillons plex urates (ammonium, ammonium originaux du a la faible concentration The 48 samples studied were vesical potassium and/or potassium enriched en phosphate et a la superposition des ammoniumn urate). The infrared study bandes. L'examen par microscopie a and/ or urethral calculi surgically of several samples heated at 6200 C balayage et l'analyse de l'energie removed from male dogs of different and 7500 C revealed the presence of dispersee par rayons X de quelques ages and breed (Tables I and II), either apatitic calcium phosphate. This echantillons selectionnes ont permis in private veterinary clinics or in the compound was difficult to detect in de completer les resultats obtenus par Department of Surgery of the Veterithe spectrum of the original samples spectroscopie infrarouge. nary Faculty of the University of due to the small proportion of Madrid. Infrared spectra of selected areas phosphate contained in the calculi and to band overlapping. The examination taken from half of the stone were INTRODUCTION of a series of selected samples by recorded on a Perkin-Elmer 599B means of scanning electron microThe incidence of canine cystine spectrophotometer, using the KBr scopy and energy dispersive X-ray urolithiasis is high in Spain. In a recent pellet technique. The other half of the analysis complemented the infrared study of 171 urinary calculi carried out stone was used in many cases for in our laboratory, cystine occurred in examination under the electron results. 26% of the cases and it was frequently microscope and/ or for calcination. accompanied by one or two additional The morphology of calculi was RESUME compounds (1). On the contrary, it has observed in a Philips SEM-500 been described in the literature that scanning electron microscope La composition et la structure de cystine calculi contain only pure equipped with EDAX analyzer. From eighteen stones of sufficient quarante-huit calculs urinaires de cystine (2,3). This conclusion may be cystine provenant de chiens ont ete due to inadequate analysis, since by size, we took half for calcination at 620 determinees a l'aide de differentes detailed examination other compo- and 7500C. At these relatively high techniques: spectrophotometrie infra- nents can be detected, as has been temperatures cystine decomposes, rouge, microscopie a balayage et reported in recent papers dealing with leaving only the accompanying minanalyse de l'energie dispersee par both human and canine urolithiasis eral components, which in the case of phosphates have undergone several rayons X. L'etude par spectroscopie (4-6). In the present work, 48 canine transformations already described in infrarouge a de montre que presque de 45% des echantillons presentaient cystine samples derived from one or the literature (7,8).
ABSTRACT
Departamento de Patologia Animal II. Patologia General y Medica. Facultad de Veterinaria de la Universidad Complutense de Madrid, 28040, Madrid, Spain (Escolar, Rodriguez) and Instituto de Optica. CSIC. Serrano, 121. 28006 Madrid, Spain (Bellanato). Submitted February 15, 1990.
Can J Vet Res 1991; 55: 67-70
67
2.5
TABLE I. Age distribution of 48 dogs with cystine uroliths
3.0
4.0
5.0
--
25
16
40 .L
/,I ~P
~j~-)H,
-~
c
12 10 9 12 4
12
9.0
80-
Number of cases
Age in years 0-2 2-4 4-6 6-8 8 Not known
7.0
6.0
l4
E 40_ c
v
,iII
3000
4000
2000
1600
800
1200
400
cm-1
Fig. 1. Infrared spectrum of a cystine calculus showing calcium oxalate.
RESULTS The age and breed of the affected dogs are presented in Tables I and II. INFRARED STUDY
The infrared analysis revealed that about 45% of the stones were composed of nearly pure cystine (> 97%). Calcium oxalate was detected in two cases in concentrations between 3 and 25%, depending on the zone examined. This compound is easily recognized by the presence of the characteristic band at about 1320 cm-' in the infrared spectrum of the cystine calculus (Fig. 1). Struvite was detected in two cases in a proportion lower than 5% of the total weight. It was recognized by the infrared bands at 1010 and 572 cm-'. Brushite (infrared bands at 3545, 3495, 1140, 1065, 990 and 875 cm-' among others) was found in one case in a proportion varying from 5 to 40%, also depending on the zone and stone analyzed. Ammonium urate and/or complex urates containing ammonium and other cations were found in two specimens. As usual, both samples consisted of several calculi of different structure. In some stones (yellow), TABLE II. Breed distribution of 48 dogs with cystine uroliths Breed Basset Hound Boxer Bulldog Collie Dachshund Fox Terrier German Shepherd Golden Retriever Labrador Retriever Miniature Pinscher Pekingese Pointer Rottweiler Setter (unspecified) Mongrels Not known
68
a
band at 1320 cm-' (l), characteristic of
peared linked by "film-like" organic matrix. Brushite was clearly differentiated from cystine in the calculus examined by SEM, both compounds appearing as firmly connected layers (Figs. 5a, Sb). In calculi containing calcium oxalate, well delimited zones of this compound were seen between zones of cystine (Figs. 6a, 6b). Finally, two mixed calculi of cystine and urates were also found (Fig. 7). As in previously studied canine urate calculi (4,9), the urates found in cystine stones consisted mainly of ammonium urate and complex urates containing ammonium and potassium. In several zones, potassium content was very high, this result suggesting the presence of potassium urate (Figs. 8 and 9). Moreover, calcium was also detected in urate
ammonium urate was mainly concentrated in the central area (see Fig. 7). In other stones (grey), the ammonium urate was heterogeneously distributed, reaching values from 8 to nearly 100%. The infrared study of 18 calcinated samples showed in ten cases the existence of calcium phosphate ( < 3%), mainly apatite, which was only suspected through the examination of the spectrum of the original calculus. This calcium apatite (nonstoichiometric hydroxyapatite) was clearly recognized because after stone calcination at 7500 C for 2 h, the spectrum of the residue (Fig. 2) corresponded to that of 13-calcium orthophosphate. SEM/EDAX STUDY
Under SEM examination, nearly perfect hexagonal cystine prisms appeared in two cases (Fig. 3), areas. although hexagonal compact cystine crystals were most commonly obDISCUSSION served. Moreover, spherulites of apatitic calcium phosphate were The incidence of cystine stones in detected in three of the samples examined, either over cystine crystals or canine urolithiasis found by us in a intermeshed with them (Fig. 4). In previous survey in dogs in the Madrid some zones, spherulites of pseudoa- area (26%) is in agreement with the morphous calcium phosphate ap- values given by other European
Number of cases 2.5
3.0
4.0
5.0
6.C
7.0
9.0 I,I
I
I.
I,
12 I
16 .1,1,1.1
1
25
40e
2 '
80-
2 3
2
1
3
3 3
C
v
4000
3000
2000
1600
1200
800
400
cm-1
2 19 3
Fig. 2. Infrared spectrum of the calcination residue of a cystine calculus containing calcium apatite (heated at 7500 C for 2 h).
Fig. 5a. Scanning electron micrograph (X320) of a calculus containing cystine and brushite. Left side: cystine; right side: brushite (Smaller bars = 10 ,um).
authors (10,11,12). However, these values are higher than those reported in the American literature, which oscilate between 1.8 and 6.8% (2,5, 13,14). Furthermore, the cystine incidence in dogs is also much higher than in humans, in which values around 1% are given (6). In relation to sex, we have only found cystine calculi in male dogs, although some authors claim to have also found them in females (5,15,16). Concerning age, although in previous reports it was stated that cystine urolithiasis tends to occur in young animals (10,15,17), the results of the present study show a wide age range. No breed seems to be especially prone to cystine urolithiasis with the
exception of mongrels, which comprise a very large proportion of the dog population. With respect to associated compounds, Ling and Ruby (5) reported the presence of apatite, brushite and uric acid/urates in canine cystine calculi. Concerning uric acid, it should be noted that these authors do not describe the techniques used for the analysis. Hesse et al (4), in a study of 160 canine cystine uroliths using infrared spectroscopy, SEM and EDAX techniques, identified calcium apatite in the majority of the stones. Moreover, they found struvite in four cases and brushite in one case. In the present work, calcium apatite was the mineral most frequently associated with cystine (at least in 55% of the samples), although, with an exception, in small proportions, not surpassing 3% of the total weight. We attribute the presence of apatite in cystine stones to an increase of the
Fig. 4. Scanning electron micrograph (X640) of a cystine calculus, showing small spherules of calcium apatite (Smaller bars = 10 ,um).
Fig. 6a. Scanning electron micrograph (X320) of the central zone of a cystine stone, showing strata of calcium oxalate (Smaller bars = 10 Mm).
Fig. 3. Scanning electron micrograph (X5000) of a cystine hexagonal prism, found in a cystine calculus (Bars = 1 ,um).
Fig. 5b. Sulphur distribution of the area shown in Fig. 5a (EDAX).
normal pH of the urine as a consequence of changes of diet. This fact may favor apatite deposits between
preformed cystine crystals. We have detected brushite only in cystine case, which consisted of several stones. The concentration of brushite depended on the zone and stone analyzed. Concentrations of brushite as high as 40% of the total weight were found. This rare phase combination of cystine and brushite is also mentioned by Hesse et al (4). Urates found in cystine stones are similar in composition and structure to other previously studied calculi mainly composed by urates (4,9). The two samples found in the present work showed, besides ammonium urate and probably potassium urate, a high proportion (at least 80%) of one
ammonium-potassium complex urates. ACKNOWLEDGMENTS The authors wish to thank Dr. J.A. Medina, Department of Geology and
Fig. 6b. Calcium distribution of the area shown in Fig. 6a (EDAX).
69
|~ ~ 'J.
----------------
-
4?,l r
Fig. 7. Scanning electron micrograph (X20) of a mixed calculus composed of cystine (outer region) and urates (central area) (Smaller bars 100 Jm).
Fig. 8. Scanning electron micrograph (X2500) of the central zone of Fig. 7 (EDAX: potassium) (Smaller bars = 1 Mm).
Fig. 9. Scanning electron micrograph (X1250) of a zone of Fig. 7 showing bundles of ammonium potassium complex urates (EDAX: potassium) together with larger cystine crystals (EDAX: sulphur) (Bars = 10 ,um).
Geochemistry, Facultad de Ciencias, Universidad Autonoma, Madrid, for
Phasen und Gefugeanalyse von Zystinsteinen. In: Gasser G, Vahlensieck W, eds. Pathogenese und Klinik der Harnsteine XIII. Darmstadt: Steinkopff, 1988: 203-207. HIDALGO A, BELLANATO J, GONZALEZ-DIAZ PF, SANTOS M. Los fosfatos de los calculos del aparato urinario. In: Problemas Actuales de Urologia. Barcelona: Salvat Editores SA, 1977: 205-211. GONZALEZ-DIAZ PF, GARCIARAMOS JV, SANTOS M. Composition of apatites in human urinary calculi. Calcif Tissue Int 1979; 28: 215-225. BELLANTO J, ESCOLAR E. Estudio comparativo de urolitos de uratos de origen humano y animal por espectroscopia infrarroja, microscopia electronica de barrido y EDAX. Opt Pur Apl 1988; 21: 217-225. CLARK WT. The distribution of canine urinary calculi and their recurrence following treatment. J Small Anim Pract 1974; 15: 437-444. DE SCHEPPER J, VAN DER STOCK J. Incidence and distribution pattern of canine urinary calculi in Belgium. Vlaams Diergeneesk Tijdschr 1980; 49: 178-186.
12. WEAVER AD. Canine urolithiasis: incidence, chemical composition and outcome of 100 cases. J Small Anim Pract 1970; 11: 93-107. 13. FINCO DR, ROSIN E, JOHNSON KH. Canine urolithiasis: A review of 133 clinical cases and 23 necropsy cases. J Am Vet Med Assoc 1970; 157: 1225-1228. 14. OSBORNE CA, CLINTON CW, DAVENPORT MP. Analyzing the mineral composition of uroliths from dogs, cats, horses, cattle, sheep, goats, and pigs. Vet Med 1989; 84: 750-764. 15. BROWN NO, PARKS JL, GREENE RW. Canine urolithiasis: retrospective analysis of 438 cases. J Am Vet Med Assoc 1977; 170: 414-418. 16. STOICHEW II. Urolithiasis in dogs from villages in Bulgaria. J Comp Pathol 1980; 90: 619-623. 17. BOVEE KC. Canine cystine urolithiasis. Vet Clin North Am (Small Anim Pract) 1986; 16: 211-215. 18. OSBORNE CA, O'BRIEN TD, GHOBRIAL HK, MEIHAK L, STEVENS JB.
his contribution in taking the scanning electron micrographs. 7.
REFERENCES 1. ESCOLAR E, BELLANATO J, MEDINA JA. Structure and composition of canine urinary calculi. Res Vet Sci (in press). 2. BOVEE KC, McGUIRE T. Qualitative and quantitative analysis of uroliths in dogs: definitive determination of chemical type. J Am Vet Med Assoc 1984; 185: 983-987. 3. DI BARTOLA SP, CHEW DJ. Canine urolithiasis. Compend Contin Educ Pract Vet 1985; 3: 201-210. 4. HESSE A, SANDERS G, LEUSMANN DB. Analysis of canine urinary stoncs using infrared spectroscopy and scanning electron microscopy. Scan Electron Microsc 1986; IV: 1705-1712. 5. LING GV, RUBY AL. Canine uroliths: analysis of data derived from 183 specimens. Vet Clin North Am (Small Anim Pract) 1986; 16: 303-316. 6. LEUSMANN DB, KLEINHANS G, POHL J, HOLZKNECHT A. Kombinierte
70
8.
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