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  • Author or Editor: Jonathan A. Lidbury x
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Abstract

Objective—To elucidate the relationship between plasma ammonia concentration and severity of hepatic encephalopathy and determine whether factors that precipitate hepatic encephalopathy in humans are associated with the presence of clinical signs of hepatic encephalopathy in dogs previously treated for the disease.

Design—Retrospective case series.

Animals—118 dogs with hepatic encephalopathy.

Procedures—The medical records database of a veterinary teaching hospital was searched for records of dogs in which hepatic encephalopathy was diagnosed between October 1, 1991, and September 1, 2014. Hepatic encephalopathy severity was graded on a 5-point scale, and the correlation between disease severity and plasma ammonia concentration was determined. Respective associations between hepatic encephalopathy and systemic inflammatory response syndrome, gastrointestinal hemorrhage, dietary indiscretion, constipation, furosemide treatment, azotemia, hypokalemia, hyponatremia, alkalosis, and hyperammonemia were assessed by Fisher exact tests followed by multivariable logistic regression.

Results—Severity of hepatic encephalopathy at hospital admission was not significantly correlated with plasma ammonia concentration. Dogs treated for hepatic encephalopathy prior to hospital admission were significantly less likely to have clinical signs of the disease at hospital admission, compared with dogs that were not treated for the disease (OR, 0.36; 95% confidence interval, 0.17 to 0.78). None of the putative precipitating factors for hepatic encephalopathy were significantly associated with the presence of clinical signs of the disease at hospital admission.

Conclusions and Clinical Relevance—Results indicated that hepatic encephalopathy treatment alleviated clinical signs of the disease. Further investigation is necessary to identify precipitating factors for hepatic encephalopathy in dogs. (J Am Vet Med Assoc 2015;247:176–183)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To test the hypothesis that intestinal pathologic changes are often concurrent with gastric pathologic changes in dogs and to characterize the historical, physical, clinicopathologic, imaging, and endoscopic findings in dogs with gastric histopathologic abnormalities.

Design—Retrospective case series.

Animals—67 dogs with gastric histopathologic abnormalities.

Procedures—Medical records from dogs that had undergone gastrotomy, gastroduodenoscopy, or gastroscopy between September 2002 and September 2007 were identified. Dogs were included in the study when histopathologic abnormalities were detected during evaluation of gastric tissue sections. History, clinical examination findings, results of diagnostic tests, diagnoses, treatments, and outcome were recorded for each dog.

Results—67 dogs with gastric histopathologic abnormalities were included in the study. The most frequent clinical sign recorded was vomiting (36/67 [53.7%] dogs). The most common biochemical abnormality recorded was panhypoproteinemia (27/64 [42.2%] dogs). Lymphoplasmacytic gastritis was the most frequent histopathologic finding recorded (34/67 [50.7%] dogs). For dogs in which both intestinal biopsy specimens and gastric biopsy specimens were collected, concurrent pathologic changes were recorded in 43 of 60 (71.7%) dogs.

Conclusions and Clinical Relevance—Results of this study suggested that intestinal pathologic changes are commonly concurrent in dogs with gastric pathologic changes. This supports the practice of collecting both gastric and duodenal biopsy specimens every time gastroduodenoscopy is performed. Lymphoplasmacytic gastritis was the most commonly recorded gastric histopathologic finding and was often of minimal or mild severity.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

Flash glucose monitoring systems (FGMS) are frequently used for interstitial glucose monitoring in dogs with diabetes mellitus and are typically placed between the scapulae. We aimed to evaluate the variability between glucose measurements from FGMS placed in 2 locations (between the scapulae and over the hip) in non-diabetic dogs during rapidly induced hypoglycemia.

ANIMALS

24 apparently healthy colony dogs that were subjects in a teaching laboratory.

PROCEDURES

Prospective interventional study. FGMS sensors (FreeStyle Libre 14-day system) were placed between the scapulae and over the hip of all dogs. Regular insulin was administered (0.3 u/kg IV) and subsequent hypoglycemia was corrected. Before insulin administration and every 10 minutes over 90 minutes, interstitial glucose was recorded from both locations, and blood glucose was measured with a point-of-care blood glucose monitor (AlphaTRAK 2).

RESULTS

There was a constant bias of 5.6 mg/dL (95% limits of agreement: −26.3 to 37.5 mg/dL) between locations, but the proportional bias was not apparent. There was a correlation between FGMS locations (r = 0.731, P = < .001). Sensor site B was clinically accurate with 100% of paired samples within Parkes error grid zones A (83%) and B (17%) but did not meet the criteria for analytical accuracy.

CLINICAL RELEVANCE

In this model of induced hypoglycemia in healthy dogs, variation between measurements from FGMS locations was unlikely to have affected the clinical outcome. Placement of FGMS over the hip may be an acceptable alternative to placement between the scapulae, but the utility in hyperglycemic dogs is unknown.

Open access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To evaluate the effects of withholding food on the results for measurements of serum concentrations of cobalamin, folate, canine pancreatic lipase immunoreactivity (cPLI), and canine trypsin-like immunoreactivity (cTLI) in healthy dogs.

ANIMALS

11 healthy employee- or student-owned dogs.

PROCEDURES

Food was withheld from the dogs for 12 hours, baseline blood samples were collected, then dogs were fed. Postprandial blood samples collected 1, 2, 4, and 8 hours later were assessed. A mixed-effects ANOVA model with fasting duration (time) as a fixed factor and dog as a random effect was fit for each analyte variable. Additionally, a mixed-effects ANOVA model controlling for the variable of time was fit to assess whether lipemia affected serum concentrations of the analytes.

RESULTS

The median serum cobalamin concentration was lower at 4 hours (428 ng/L) and 8 hours (429 ng/L) postprandially, compared with baseline (479 ng/L), but this difference was not clinically meaningful. Although there were no substantial differences in serum concentrations of folate, cPLI, or cTLI, postprandial changes in serum concentrations of cTLI or folate could potentially affect diagnoses in some dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Although results indicated that feedings rarely resulted in clinically important differences in the median serum concentrations of cobalamin, folate, cPLI, or cTLI in healthy dogs, given the further processing required for lipemic samples, withholding food for at least 8 hours is an appropriate recommendation when measuring these analytes. Similar research is needed in dogs with gastrointestinal disease to determine whether the withholding of food is necessary when measuring these analytes in affected dogs.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To develop and validate a sandwich ELISA for the measurement of α1-proteinase inhibitor (α1-PI) concentrations in serum and fecal samples obtained from common marmosets (Callithrix jacchus).

SAMPLE Leftover serum (n = 42) and fecal (23) samples submitted for diagnostic testing; paired serum and fecal samples obtained from 30 common marmosets at 2 research colonies.

PROCEDURES A sandwich ELISA was developed and analytically validated by determining the lower limit of detection, linearity, accuracy, precision, and reproducibility. Reference intervals for α1-PI concentrations in serum and feces of common marmosets were calculated.

RESULTS The standard curve was generated for concentrations between 1 and 100 ng/mL. Mean ± SD observed-to-expected ratio for serial dilutions of serum and fecal samples was 117.1 ± 5.6% (range, 112.2% to 123.0%) and 106.1 ± 19.7% (range, 82.6% to 130.2%), respectively. Mean observed-to-expected ratio for spiking recovery of serum and fecal samples was 102.9 ± 12.1% (range, 86.8% to 115.8%) and 97.9 ± 19.0% (range, 83.0% to 125.1%), respectively. Reference interval for serum concentrations of α1-PI was 1,254 to 1,813 μg/mL, for 3-day mean fecal concentrations was 11.5 to 42.2 μg/g of feces, and for 3-day maximum fecal concentrations was 13.2 to 51.2 μg/g of feces.

CONCLUSIONS AND CLINICAL RELEVANCE The ELISA was linear, accurate, precise, and reproducible for quantification of α1-PI concentrations in serum and feces of common marmosets. However, the ELISA had limited linearity and accuracy for spiking recovery of fecal samples.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To analytically validate a gas concentration of chromatography–mass spectrometry (GC-MS) method for measurement of 6 amino acids in canine serum samples and to assess the stability of each amino acid after sample storage.

SAMPLES Surplus serum from 80 canine samples submitted to the Gastrointestinal Laboratory at Texas A&M University and serum samples from 12 healthy dogs.

PROCEDURES GC-MS was validated to determine precision, reproducibility, limit of detection, and percentage recovery of known added concentrations of 6 amino acids in surplus serum samples. Amino acid concentrations in serum samples from healthy dogs were measured before (baseline) and after storage in various conditions.

RESULTS Intra- and interassay coefficients of variation (10 replicates involving 12 pooled serum samples) were 13.4% and 16.6% for glycine, 9.3% and 12.4% for glutamic acid, 5.1% and 6.3% for methionine, 14.0% and 15.1% for tryptophan, 6.2% and 11.0% for tyrosine, and 7.4% and 12.4% for lysine, respectively. Observed-to-expected concentration ratios in dilutional parallelism tests (6 replicates involving 6 pooled serum samples) were 79.5% to 111.5% for glycine, 80.9% to 123.0% for glutamic acid, 77.8% to 111.0% for methionine, 85.2% to 98.0% for tryptophan, 79.4% to 115.0% for tyrosine, and 79.4% to 110.0% for lysine. No amino acid concentration changed significantly from baseline after serum sample storage at −80°C for ≤ 7 days.

CONCLUSIONS AND CLINICAL RELEVANCE GC-MS measurement of concentration of 6 amino acids in canine serum samples yielded precise, accurate, and reproducible results. Sample storage at −80°C for 1 week had no effect on GC-MS results.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To develop and analytically validate a liquid chromatography–tandem mass spectrometry method for measurement of endogenous trans-4-hydroxy-l-proline concentrations in canine serum and to assess serum trans-4-hydroxy-l-proline concentrations in dogs with chronic hepatitis.

SAMPLE

Serum samples obtained from 20 dogs with histopathologically confirmed chronic hepatitis and 20 healthy control dogs.

PROCEDURES

A liquid chromatography–tandem mass spectrometry method for quantification of trans-4-hydroxy-l-proline concentration was developed and assessed for analytic sensitivity, linearity, accuracy, precision, and reproducibility. Serum concentration of trans-4-hydroxy-l-proline in dogs with chronic hepatitis and healthy control dogs was measured.

RESULTS

Observed-to-expected ratios for dilutional parallelism ranged from 72.7% to 111.5% (mean ± SD, 91.3 ± 19.6%). Intra-assay and interassay coefficients of variation ranged from 2.1% to 3.0% and 3.2% to 5.3%, respectively. Relative error ranged from −2.3% to 7.8%. Trans-4-hydroxy-l-proline concentrations were significantly lower in serum obtained from dogs with chronic hepatitis (median, 0.24 ng/mL; range, 0.06 to 1.84 ng/mL) than in serum obtained from healthy control dogs (median, 0.78 ng/mL; range, 0.14 to 4.90 ng/mL).

CONCLUSIONS AND CLINICAL RELEVANCE

The method described here for the quantification of trans-4-hydroxy-l-proline concentration in canine serum was found to be sensitive, specific, precise, accurate, and reproducible. Dogs with chronic hepatitis had significantly lower serum trans-4-hydroxy-l-proline concentrations than did healthy control dogs, possibly as a result of altered hepatic metabolism of amino acids.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To determine the effects of leukoreduction on N-methylhistamine (NMH; a stable histamine metabolite) concentration in units of canine whole blood during storage and incubation at room temperature (approx 22 °C) to simulate temperature conditions during transfusion.

ANIMALS

8 healthy adult Walker Hounds.

PROCEDURES

A standard unit of blood (450 mL) was obtained from each dog twice, with at least 28 days between donations. Blood units collected from 4 dogs during the first donation underwent leukoreduction, whereas the blood units collected from the other 4 dogs did not undergo leukoreduction, prior to storage at 4 °C. The alternate treatment was applied to blood units collected during the second donation. A sample from each unit was obtained for determination of plasma NMH concentration the day of donation (before and after leukoreduction when applicable) and before and after incubation at room temperature for 5 hours on days 14 and 28 of storage.

RESULTS

Units that underwent leukoreduction had substantially lower leukocyte and platelet counts than nonleukoreduced units. Plasma NMH concentration increased immediately after leukoreduction but did not change significantly during the subsequent 28 days of storage, nor did it differ between units that did and did not undergo leukoreduction.

CONCLUSIONS AND CLINICAL RELEVANCE

Leukoreduction and simulated transfusion temperature did not affect the histamine load in units of canine whole blood during the first 28 days of storage. Further research is necessary to determine whether histamine contributes to the development and severity of blood transfusion reactions in dogs.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE

To characterize gastrointestinal transit times (GITTs) and pH in dogs, and to compare to data recently described for cats.

ANIMALS

7 healthy, colony-housed Beagles.

PROCEDURES

The GITTs and pH were measured using a continuous pH monitoring system. For the first period (prefeeding), food was withheld for 20 hours followed by pH capsule administration. Five hours after capsule administration, dogs were offered 75% of their historical daily caloric intake for 1 hour. For the second period (postfeeding), food was withheld for 24 hours. Dogs were allowed 1 hour to eat, followed by capsule administration. Both periods were repeated 3 times. The GITTs and pH were compared to published feline data.

RESULTS

The mean ± SD transit times in dogs for the pre- and postfeeding periods, respectively, were esophageal, 3 ± 5 minutes and 13 ± 37 minutes; gastric, 31 ± 60 minutes and 829 ± 249 minutes; and intestinal, 795 ± 444 minutes and 830 ± 368 minutes. The mean ± SD gastrointestinal pH in dogs for the pre- and postfeeding periods, respectively, were esophageal, 6.6 ± 0.6 and 5.7 ± 1.0; gastric, 3.0 ± 1.4 and 1.8 ± 0.3; intestinal, 7.9 ± 0.3 and 7.7 ± 0.6; first-hour small intestinal, 7.6 ± 0.5 and 7.1 ± 0.4; and last-hour large intestinal, 7.9 ± 0.6 and 7.7 ± 1.0. The first-hour small intestinal pH and total transit times varied between dogs and cats depending on feed period (P = .002 and P = .04, respectively). Post hoc analysis revealed significantly shorter total transit times in dogs prefeeding (P = .005; mean ± SD for cats, 2,441 ± 1,359 minutes; for dogs, 828 ± 439 minutes) and postfeeding (P = .03; mean ± SD for cats, 3,009 ± 1,220 minutes; for dogs, 1,671 ± 513 minutes). Total transit time for dogs was also shorter pre- versus postfeeding (P = .003).

CLINICAL RELEVANCE

GITT is faster in Beagles compared to cats, but gastrointestinal pH are similar when fed the same diet.

Open access
in Journal of the American Veterinary Medical Association