Search Results

Abstract

OBJECTIVE To evaluate the clinical performance of a veterinary benchtop dry chemistry analyzer for measurement of plasma ammonium concentrations in dogs by comparing results with those obtained by a reference standard test method.

DESIGN Prospective evaluation study.

SAMPLE 32 blood samples from 30 dogs (16 with and 14 without suspected hepatobiliary disease).

PROCEDURES Blood samples were collected by jugular venipuncture. A veterinary benchtop dry chemistry analyzer and a reference standard (enzymatic) test method were used to measure ammonium concentrations in plasma collected from heparinized whole blood. Bland-Altman plots were used to assess intermethod agreement. Results were compared by linear regression, and correlation was calculated by the Pearson method. Samples were classified as having high or normal ammonium concentrations on the basis of cutoff data for the relevant test method; results were compared between methods to evaluate diagnostic agreement.

RESULTS 31 of 32 (97%) samples were classified correctly with the benchtop analyzer; 1 sample with a high ammonium concentration was classified as having a normal value (ie, false-negative result) by this method. A strong positive correlation (r ² = 0.989) was found between methods, with constant, proportional, negative bias for benchtop analyzer results. The interassay coefficient of variation (ie, precision) for measurement of an internal standard with the benchtop analyzer was 2.74% (n = 20 repetitions).

CONCLUSIONS AND CLINICAL RELEVANCE The dry chemistry analyzer used in the study had acceptable clinical performance for detection of high versus normal ammonium concentrations in canine plasma, indicating the method can be used to aid diagnosis in dogs with suspected hepatobiliary disease.

Abstract

Objective—To investigate postprandial changes in serum concentrations of unconjugated bile acids in healthy Beagles.

Animals—7 healthy Beagles.

Procedure—Blood samples were obtained from dogs at regular intervals up to 8 hours after consumption of a meal. Serum concentrations of 5 unconjugated bile acids were determined at each time point, using gas chromatography-mass spectrometry with selected ion monitoring.

Results—Total serum unconjugated bile acid concentration was significantly increased, relative to baseline values, at 360, 420, and 480 minutes after feeding. Unconjugated cholic acid was significantly increased at 360, 420, and 480 minutes. The proportion of total unconjugated bile acids represented by cholic acid was significantly increased at 240 to 480 minutes. Deoxycholic acid was significantly increased at 360 and 420 minutes. Chenodeoxycholic acid was significantly increased at 360 to 480 minutes. Lithocholic acid was significantly increased at 180 minutes, whereas no significant changes in ursodeoxycholic acid were detected at any time point.

Conclusion and Clinical Relevance—Healthy Beagles had significant increases in serum concentrations and changes in the profile of unconjugated bile acids after a meal. These increases persisted > 8 hours, indicating that prolonged withholding of food is necessary when to avoid the risk of a false-positive diagnosis when assessing serum unconjugated bile acid concentrations in dogs. (Am J Vet Res 2002;63:789–793

Abstract

Objective—To validate an automated chemiluminescent immunoassay for measuring serum cobalamin concentration in cats, to establish and validate gas chromatography-mass spectrometry techniques for use in quantification of methylmalonic acid, homocysteine, cysteine, cystathionine, and methionine in sera from cats, and to investigate serum concentrations of methylmalonic acid, methionine, homocysteine, cystathionine, and cysteine as indicators of biochemical abnormalities accompanying severe cobalamin (vitamin B₁₂) deficiency in cats.

Sample Population—Serum samples of 40 cats with severe cobalamin deficiency (serum cobalamin concentration < 100 ng/L) and 24 control cats with serum cobalamin concentration within the reference range.

Procedure—Serum concentrations of cobalamin were measured, using a commercial automated chemiluminescent immunoassay. Serum concentrations of methylmalonic acid, methionine, homocysteine, cystathionine, and cysteine were measured, using gas chromatography-mass spectrometry, selected ion monitoring, stable-isotope dilution assays.

Results—Cats with cobalamin deficiency had significant increases in mean serum concentrations of methylmalonic acid (9,607 nmol/L), compared with healthy cats (448 nmol/L). Affected cats also had substantial disturbances in amino acid metabolism, compared with healthy cats, with significantly increased serum concentrations of methionine (133.8 vs 101.1 µmol/L) and significantly decreased serum concentrations of cystathionine (449.6 vs 573.2 nmol/L) and cysteine (142.3 vs 163.9 µmol/L). There was not a significant difference in serum concentrations of homocysteine between the 2 groups.

Conclusions and Clinical Relevance—Cats with gastrointestinal tract disease may have abnormalities in amino acid metabolism consistent with cobalamin deficiency. Parenteral administration of cobalamin may be necessary to correct these biochemical abnormalities. (Am J Vet Res 2001;62:1852–1858)

Abstract

Objective—To develop and validate a gas chromatography–mass spectrometry (GC-MS) method for determination of N^τ-methylhistamine (NMH) concentration in canine urine and fecal extracts and to assess urinary NMH concentrations in dogs with mast cell neoplasia and fecal NMH concentrations in dogs with protein-losing enteropathy.

Sample Population—Urine specimens were collected from 6 healthy dogs and 7 dogs with mast cell neoplasia. Fecal extracts were obtained from fecal specimens of 28 dogs with various severities of protein-losing enteropathy, as indicated by fecal concentration of α₁-proteinase inhibitor.

Procedures—NMH was extracted directly from urine, and fecal specimens were first extracted into 5 volumes of PBSS containing 1% newborn calf serum. N^τ-methylhistamine in specimens was quantified via stable isotope dilution GC-MS. The assay was validated via determination of percentage recovery of known amounts of NMH and interassay coefficients of variation. Urinary excretion of NMH was evaluated by means of NMH-to-creatinine concentration ratios.

Results—Recovery of NMH in urine and fecal extracts averaged 104.6% and 104.5%, respectively. Interassay coefficients of variation ranged from 5.4% to 11.7% in urine and 12.6% to 18.1% in fecal extracts. Urinary NMH excretion was significantly increased in dogs with mast cell neoplasia, compared with that in healthy dogs. No correlation was detected between severity of protein-losing enteropathy and fecal NMH concentration.

Conclusions and Clinical Relevance—This method provided a sensitive, reproducible means of measuring NMH in canine urine and fecal extracts. High urinary NMH-to-creatinine concentration ratios in dogs with mast cell neoplasia are consistent with increased histamine release in this disease.

Abstract

OBJECTIVE To assess clinical effects of an omega-3 fatty acid and protein-enriched diet, physical rehabilitation, or both in dogs following tibial plateau leveling osteotomy (TPLO) and arthroscopic surgery for cranial cruciate ligament (CCL) disease.

DESIGN Randomized, prospective clinical trial.

ANIMALS 48 dogs with unilateral CCL disease.

PROCEDURES Dogs were randomly assigned to receive a dry omega-3 fatty acid and protein-enriched dog food formulated to support joint health (test food [TF]), a dry food formulated for maintenance of adult dogs (control food [CF]), TF plus rehabilitation (TF-R), or CF plus rehabilitation (CF-R). Data collected over 6 months included body weight, body condition score, ground reaction force data, tibial plateau angle, limb circumference measurements, subjective pain and lameness scores assigned by surgeons and dog owners, and daily activity measured by accelerometry.

RESULTS Peak vertical force and vertical impulse were greater after surgery for dogs in the TF groups than in the CF groups; peak vertical force was greater after surgery in dogs that underwent rehabilitation than in those that did not. Owner scores indicated lower frequencies of lameness and signs of pain during some activities for the TF group, compared with other groups, and for the TF-R and CF-R groups, compared with the CF group. Sedentary time decreased and time spent in light-to-moderate or vigorous activity increased in all groups over time. Rehabilitation was significantly associated with greater time spent in light-to-moderate activity, regardless of diet.

CONCLUSIONS AND CLINICAL RELEVANCE Feeding the TF and providing physical rehabilitation during the first 6 months after TPLO were associated with improvements in some indices of clinical outcome and function in dogs. Significant interactions between time and some outcome variables were observed, indicating further research is warranted.

Abstract

Objective—To characterize historical, clinicopathologic, ultrasonographic, microbiological, surgical, and histopathologic features of bacterial cholecystitis and bactibilia in dogs and evaluate response to treatment and outcomes in these patients.

Design—Retrospective case-control study.

Animals—40 client-owned dogs (10 with bacterial cholecystitis on histologic analysis or bactibilia on cytologic examination [case dogs] and 30 without bactibilia [controls]) evaluated at a veterinary teaching hospital between 2010 and 2014.

Procedures—Signalment, history, clinicopathologic findings, ultrasonographic features, microbiological results, surgical findings, histopathologic changes, treatments, and outcomes of case dogs were derived from medical records and summarized. Demographic and clinicopathologic data and ultrasonographic findings were compared between case and control dogs. Relationships among prior antimicrobial treatment, sediment formation in the gallbladder, presence of immobile biliary sludge, and presence of bactibilia or bacterial cholecystitis were assessed.

Results—No finding was pathognomonic for bactibilia or bacterial cholecystitis in dogs. Case dogs were significantly more likely to have immobile biliary sludge and had a greater degree of biliary sediment formation than did control dogs. All case dogs for which gallbladders were examined histologically (6/6) had bacterial cholecystitis. Five of 10 case dogs were Dachshunds. Medical or surgical treatment resulted in good outcomes.

Conclusions and Clinical Relevance—Bactibilia and bacterial cholecystitis were important differential diagnoses in dogs with signs referable to biliary tract disease. Dachshunds were overrepresented, which may suggest a breed predisposition. Cytologic evaluation of bile should be considered in the routine assessment of dogs with hepatobiliary disease if immobile biliary sludge is present. (J Am Vet Med Assoc 2015;246:982–989)

Abstract

Objective—To purify and partially characterize various isoforms of canine pepsinogen (PG) from gastric mucosa.

Sample Population—Stomachs obtained from 6 euthanatized dogs.

Procedure—Mucosa was scraped from canine stomachs, and a crude mucosal extract was prepared and further purified by use of weak anion-exchange chromatography, hydroxyapatite chromatography, sizeexclusion chromatography, and strong anionexchange chromatography. Pepsinogens were characterized by estimation of molecular weights, estimation of their isoelectric points (IEPs), and N-terminal amino acid sequencing.

Results—Two different groups of canine PG were identified after the final strong anion-exchange chromatography: PG A and PG B. Pepsinogens differed in their molecular weights and IEP. Pepsinogen B appeared to be a dimer with a molecular weight of approximately 34,100 and an IEP of 4.9. Pepsinogen A separated into several isoforms. Molecular weights for the various isoforms of PG A ranged from 34,200 to 42,100, and their IEPs ranged from 4.0 to < 3.0. The N-terminal amino acid sequence for the first 25 amino acid residues for PG A and B had good homology with the amino acid sequences for these proteins in other species.

Conclusions and Clinical Relevance—Canine PG B and several isoforms of canine PG A have been purified. Availability of these PGs will facilitate development of immunoassays to measure PG in canine serum as a potential diagnostic marker for gastric disorders in dogs. (Am J Vet Res 2002;63:1585–1590)

Abstract

Objective—To develop and validate an ELISA for measurement of serum canine pepsinogen A (cPG A) as a diagnostic marker of gastric disorders in dogs and to measure serum cPG A in healthy dogs after food deprivation and after feeding.

Sample Population—Sera from 72 healthy dogs.

Procedure—A sandwich ELISA was developed and validated. The reference range for serum concentrations of cPG A was determined in 64 healthy dogs. Postprandial changes in serum concentrations of cPG A were evaluated in 8 healthy dogs.

Results—Assay sensitivity was 18 µg/L, and the maximum detectable concentration was 1,080 µg/L. The observed-to-expected ratio (O:E) for 3 serial dilutions of 3 serum samples ranged from 69.3 to 104.1%. The O:E for 3 serum samples spiked with 8 concentrations of cPG A ranged from 58.8 to 120.4%. Coefficients of variation for intra- and interassay variability of 3 serum samples ranged from 7.6 to 11.9% and from 10.1 to 13.1%, respectively. Mean ± SD serum concentration of cPG A in healthy dogs was 63.8 ± 31.0 µg/L and the reference range was 18 to 129 µg/L. Significant increases in serum concentrations of cPG A were observed between 1 and 7 hours after feeding.

Conclusions and Clinical Relevance—The ELISA for measuring cPG A was sufficiently sensitive, linear, accurate, precise, and reproducible for clinical use. Serum concentrations of cPG A increase substantially after feeding, which should be taken into account when conducting clinical studies. (Am J Vet Res 2003;64:1146–1150)

Abstract

OBJECTIVE To determine the effects of an omega-3 fatty acid and protein–enriched diet, physical rehabilitation, or both on radiographic findings and markers of synovial inflammation in dogs following tibial plateau leveling osteotomy and arthroscopic surgery for treatment of cranial cruciate ligament disease.

DESIGN Randomized, prospective clinical trial.

ANIMALS 48 dogs with unilateral cranial cruciate ligament disease.

PROCEDURES Dogs were randomly assigned to receive a dry omega-3 fatty acid and protein–enriched dog food formulated to support joint health (test food [TF]), a dry food formulated for adult canine maintenance (control food [CF]), TF plus rehabilitation, or CF plus rehabilitation after surgery. Synovial fluid prostaglandin (PG) E₂ and interleukin-1β concentrations, radiographic osteoarthritis scores, osteotomy site healing, and patellar ligament thickness were assessed at predetermined time points up to 6 months after surgery.

RESULTS Dogs that received CF had significantly higher PGE₂ concentrations over time following surgery than did dogs that received TF, regardless of rehabilitation status. Synovial fluid interleukin-1β concentrations did not change over time in any groups. Diet and rehabilitation were both associated with osteoarthritis scores, with significantly lower scores over time for dogs that received TF versus CF and for dogs that underwent rehabilitation versus those that did not. Proportions of dogs with complete osteotomy healing 8 and 24 weeks after surgery were significantly lower for dogs that received TF than for dogs that received CF, regardless of rehabilitation status.

CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that feeding the TF can result in lower synovial fluid PGE₂ concentrations and that both the TF and rehabilitation can reduce progression of osteoarthritis in the 6 months following tibial plateau leveling osteotomy; clinical relevance of slower osteotomy healing in dogs fed the TF was unclear.