Search Results

You are looking at 1 - 10 of 14 items for

  • Author or Editor: Deedra L. Johnson x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract

Objective

To determine extent and nature of regional differences in distribution of canine urinary calculi.

Sample population

13,552 calculus specimens: 7,056 (52.1%) from females, 6,492 (47.9%) from males, and 4 from dogs of unrecorded sex.

Procedure

Records were used to compile information from all specimens submitted between July 1981 and December 1995. Results from mixed-breed and various breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of dogs, and anatomic location and mineral composition of specimens were analyzed and compared for 6 US geographic regions.

Results

Struvite-, apatite-, and urate-containing calculi were reported significantly most often from female dogs of the Mountain/Pacific region. Oxalate-, silica-, and brushite-containing calculi were reported significantly most often from male dogs in the New England/mid-Atlantic (NEMA) region. Cystine-containing calculi were reported most frequently from the NEMA and South Central (SC) regions. Dogs from the NEMA region were oldest in average age at diagnosis. Significant regional differences in distribution were found for several breeds. Sex distribution of renal calculi in 11 breeds of dogs (Lhasa Apso, Yorkshire Terrier, Shih Tzu, Basset Hound, Pug, Mastiff, Bichon Frise, Doberman Pinscher, Dalmatian, English Bulldog, and Pekingese) reported to be at high risk of renal lithiasis differed among the 6 geographic regions. Renal and ureteral calculi were reported significantly most often from dogs in the South Atlantic region, and bladder and urethral calculi were reported most often from dogs in the SC region.

Conclusions

Wide regional differences exist in distribution of stone-forming dogs by sex, average age at diagnosis, breed, and minerals contained within and anatomic location of calculi. (Am J Vet Res 1999;60:29–42)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compile and statistically analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis.

Sample Population

11,000 canine urinary calculus specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

Procedure

Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding all canine urinary calculus specimens submitted for analysis between July 1981 and January 1994. Interrelations of sex and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically.

Results

Urolithiasis was associated with growth of bacteria isolated from urine or calculi, or both, in 65% of females and nearly 44% of males. Staphylococcus intermedius was isolated most often from either sex (54% for females, 30% for males). In addition to staphylococci, 22 other bacterial species were isolated from specimens from females, and 17 other bacterial species and 1 species of yeast were isolated from males. A single bacterial species was isolated from 87.6% of cultures from females and from nearly 90% of cultures from males. Among females, nearly 98% of pure cultures of staphylococci were associated with calculi that contained struvite; this was true for 80% of pure cultures of staphylococci from males.

Conclusions and Clinical Relevance

There are wide sex differences in prevalence of urolithiasis- and specific mineral-associated bacterial infections. In several instances, bacterial infections were significantly related to urinary calculus location. These variables should be considered in any evaluation of canine patients that have uroliths. (Am J Vet Res 1998;59:643–649)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To analyze selected breed-related data for canine urinary calculi.

Sample Population

11,000 specimens: 5,781 from female dogs, 5,215 from males, and 4 from dogs of unrecorded sex.

Procedure

Information was compiled for all canine urinary calculi submitted between July 1981 and January 1994. Results for a mixed-breed group and 26 of the most common breeds of stone-forming dogs were analyzed. Interrelations of breed, sex, and age of affected dogs and mineral composition of the specimens were determined.

Results

Prevalence of 5 specific mineral types was significantly correlated between the sexes of 27 common breed groups: struvite, calcium phosphate (apatite), calcium oxalate, brushite, and urate. Struvite-containing calculi were seen in high proportions in both sexes of 7 breeds, and in low proportions in both sexes of 7 other breeds. Male and female Lhasa Apsos, Cairn Terriers, and 5 other breeds had high proportions of oxalate-containing calculi; values in males were substantially higher. Low numbers of oxalate-containing calculi were seen in both sexes of 7 breeds; Dalmatians had the lowest numbers. Males and females of 6 breeds had high numbers of urate-containing calculi, Dalmatians and English Bulldogs had the highest numbers. Low amounts of urate were found in calculi from males and females of 6 breeds, Samoyeds had the lowest numbers. Highest proportions of cystine-containing calculi were seen in male Dachshunds, English Bulldogs, and Chihuahuas. Males of 8 breeds had no specimens that contained cystine; only 2 such specimens were obtained from females.

Conclusions

Prevalence of uroliths differs among breed, age, and sex of affected dogs.

Clinical Relevance

Breed, sex, and age of dogs; mineral types of calculi in males versus females; and their anatomic location within the tract are important considerations for clinicians when evaluating risk in dogs with urolithiasis and in identifying areas that need further in-depth applied or clinical investigation, or both. (Am J Vet Res 1998;59:630–642)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To compile and analyze selected data from a large number of canine urinary calculus specimens that were subjected to quantitative, layer-by-layer mineral analysis.

Sample Population

11,000 canine urinary calculus specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

Procedure

Records of the Urinary Stone Analysis Laboratory, School of Veterinary Medicine, University of California were used to compile information regarding urinary calculus specimens from dogs. Records surveyed were of all canine calculi submitted for analysis between July 1981 and January 1994. Results analyzed included those of a mixed-breed group and 26 common breeds of stone-forming dogs. Interrelations of breed, sex, and age of the affected dogs, mineral composition of the specimens, and associated urinary tract infections were analyzed statistically.

Results

Proportions of culture-positive specimens were significantly correlated between the sexes (r = 0.494, P = 0.008). Staphylococcus intermedius was isolated most often from either sex, ranging from 36.1% (Basset Hounds) to 67.9% (Pekingese) of cultured specimens from females and 8.7% (Chihuahuas) to 71.4% (Scottish Terriers) of specimens from males. The second most frequently isolated bacterial species, Escherichia coli, ranged from 0% in males of 2 breeds and females of 4 breeds to 25% in Cairn Terrier males and 19.4% in Basset Hound females. Streptococcus spp were the third most frequently isolated bacterial species. Significant correlations between the sexes were found for percentages of calculi located in the urinary bladder (r = 0.490, P = 0.008), and for calculi voided in the urine (r = 0.503, P = 0.006).

Conclusions

Breed and sex differences in prevalence of urolithiasis- and mineral-associated bacterial infections are numerous. Staphylococcus intermedius was the most common isolate from specimens from all but 3 of 54 breed/sex groupings. For either sex, streptococcal infections were significantly related to proportions of calculi passed in the urine. (Am J Vet Res 1998;59:650–660)

Free access
in American Journal of Veterinary Research

Summary

One hundred fifty specimens of urinary calculi from 150 cats were analyzed by at least 1 of 4 quantitative methods. Struvite (magnesium ammonium phosphate) was the predominant mineral substance encountered, with 104 (69%) of the calculi being composed entirely of struvite and 23 (15%) being composed partially of struvite. Most (93%) of the calculi were located in the urinary bladder. Growth of bacteria was observed in samples from calculi or urine from 30 (41%) of 74 cats. Coagulase-positive staphylococci were isolated from the urine or calculi from 17 cats (45% of bacteria isolated). Ten other bacterial species were isolated. Median and mean ages of the cats were 5.0 and 5.1 years, respectively. Domestic shorthair and domestic longhair breeds predominated. Fifty-seven percent of the calculi came from females, 43% from males. The distribution by gender did not differ significantly (P > 0.2) among the 3 groups (domestic shorthair, domestic longhair, and other). However, the distribution of struvite calculi differed significantly (χ2 = 15.5, P < 0.001) by age and gender; among cats ≤ 2 years of age, males predominated 2:1 over females, and among cats > 2 years of age, females predominated by nearly 3:1 over males. When compared with the general population, females > 2 years old were significantly (χ2 = 15.4, P < 0.001) overrepresented.

Free access
in Journal of the American Veterinary Medical Association

Summary

Clinical features and laboratory findings were evaluated in 10 dogs that formed xanthine-containing urinary calculi during the period that they were given allopurinol (9 to 38 mg/kg of body weight/d). Duration of allopurinol treatment was 5 weeks to 6 years. Of the 10 dogs, 9 (all Dalmatians) had formed uric acid-containing calculi at least once before allopurinol treatment was initiated. It was not possible to recognize xanthine as a crystalline component of the calculi by use of a chemical colorimetric method or by polarized light microscopy. We concluded that the best diagnostic method for recognition of xanthine-containing calculi was high-pressure liquid chromatography because it is quantitative, sensitive, and accurate, and can be conducted on a small amount (1 to 2 mg) of crystalline material.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To elucidate the ultrastructural details of calcium oxalate-containing urinary calculi from dogs.

Sample Population—38 specimens selected from a collection of 8,297 oxalate-containing urinary calculi from dogs: 22 specimens composed of calcium oxalate (calcium oxalate monohydrate [COM], calcium oxalate dihydrate [COD], or COM and COD) and 16 specimens composed of calcium oxalate with amorphous calcium phosphate.

Procedure—Analyses of specimens included use of plain, reflected, and polarized light microscopy, X-ray diffractometry, scanning electron microscopy (SEM) with backscattered electron (BSE) imagery, and electron microprobe analysis.

Results—Four texture types were observed in calcium oxalate calculi; 4 texture types of calcium oxalatecalcium phosphate-mixed calculi were recognized. Texture types were delineated through differences in calcium oxalate crystal sizes, which were affected by urine supersaturation and abundance of crystal nucleation sites. Segregation of calcium oxalate from calcium phosphate indicated they do not precipitate under the same conditions. Deposition of calcium phosphate between calcium oxalate crystals decreased the volume of pore spaces within calculi. Porosity was observed along boundaries between COM and COD. Minute pores increased the surface area of calculi exposed to urine, and this increase in liquid-solid interface promotes interaction of crystals with the surrounding urine.

Conclusions and Clinical Relevance—Calcium oxalate urolithiasis is of major concern, because it is often a recurrent disease among dogs, principally treated by surgical removal of calculi, with few effective dissolution strategies. Understanding the ultrastructure and mineralogic content of calcium oxalate and its association with amorphous calcium phosphate is a step toward the solution of this increasingly important medical problem. (Am J Vet Res 2001;62:237–247)

Full access
in American Journal of Veterinary Research

Abstract

Objective

To compile and statistically analyze selected data from a large number of canine urinary calculi.

Sample Population

11,000 specimens: 5,781 from female dogs, 5,215 from male dogs, and 4 from dogs of unrecorded sex.

Procedure

Records were used to compile information from all canine calculi analyzed between July 1981 and January 1994. Interrelations of mineral composition, location of specimens within the urinary tract, age and sex of affected dogs, and number of previous episodes of urolithiasis were determined.

Results

Approximately 70% of the specimens were from a first episode of urolithiasis. Calculi were located in the urinary bladder of 93.1% of females and 79.0% of males, and in the upper urinary tract of 4% of females and 2% of males. Calculi were found in multiple sites in 23.1% of males and 5.2% of females. Significantly higher proportions of struvite, apatite, and urate were found in uroliths from females; oxalate, cystine, silica, and brushite were significantly more prevalent in males. Sixty-one percent of specimens from males and 29% from females were composed of a single mineral substance. The most common mineral combination of 2 or more minerals included struvite and apatite. An additional 67 specimens from male dogs and 49 from female dogs contained other mineral combinations. In 48% of specimens from males and nearly 62% of specimens from females, the minerals formed several distinct layers of differing composition.

Conclusions

Male and female dogs form urinary calculi composed of 1 or more of several distinct minerals. Prevalence of canine uroliths differs between ages and between the sexes. Many specimens contain complex layering of minerals; most specimens were found in the urinary bladder.

Clinical Relevance

Sex and age of dogs, mineral types of likely calculi in males versus females, and their anatomic location are important considerations for clinicians when evaluating risk in dogs with urolithiasis. (Am J Vet Res 1998;59:624–629)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To elucidate the ultrastructural details of struvite-containing urinary calculi from dogs.

Sample Population

38 specimens were selected from a collection of approximately 13,000 canine urinary calculi: 18 of these were composed entirely of struvite, and 20 consisted of struvite and calcium phosphate (apatite).

Procedure

Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron microprobe analysis.

Results

4 textural types were recognized among struvite calculi, and 4 textural types of struvite-apatite calculi were described. Evidences of calculus dissolution were described from 4 calculi studied.

Conclusions

The presence of small, well interconnected primary pores in struvite-containing urinary calculi from dogs appears to be a significant factor in determining the possible interaction of calculi with changes in the urine composition. The progress of dissolution from the calculus surface to the calculus interior appears to be largely affected by the primary porosity originally present between crystals forming the calculus framework. Apatite was observed to be more resistant to dissolution than struvite.

Clinical Relevance

The prevalence of fine concentric laminations having low porosity, and the common occur-rence of apatite among struvite-containing urinary calculi from dogs may be 2 reasons why the efficacy of dietary and medicinal manipulations in dissolving urinary calculi is greater among cats than it is among dogs. (Am J Vet Res 1996;57:1274-1287)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To elucidate the ultrastructural details of struvite-containing urinary calculi from cats.

Design

Specimens studied were inclusive of the range of textures visible during preliminary analysis by use of a stereoscopic dissecting microscope. Textural types, which were used to infer crystal growth conditions, were differentiated with regard to crystal habit, crystal size, growth orientation, and primary porosity.

Sample Population

Thirty specimens were selected from a collection of approximately 1,600 feline urinary calculi: 20 of these were composed entirely of struvite, and 10 consisted of struvite and calcium phosphate (apatite).

Procedure

Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron probe microanalysis.

Results

Four textural types were recognized among struvite calculi, whereas 2 textural types of struvite-apatite calculi were described.

Conclusions

The presence of minute, well interconnected primary pores in struvite-containing urinary calculi from cats is an important feature, which may promote possible interaction of calculi with changes in urine composition.

Clinical Relevance

Primary porosity, which can facilitate interaction between the calculus and changing urine composition, may explain the efficacy of dietary or medicinal manipulations to promote the dissolution of struvite-containing uroliths from this species. (Am J Vet Res 1996;57:12–24)

Free access
in American Journal of Veterinary Research