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Abstract

Objective—To evaluate concordance among veterinary pathologists in the assessment of histologic findings in the pars intermedia of pituitary gland sections from aged horses with mild signs suggestive of pituitary pars intermedia dysfunction (PPID).

Sample Population—10 pituitary glands from aged horses.

Procedure—7 pathologists were provided with signalment, clinical signs, and a single H&E-stained pituitary gland section from 10 aged horses with mild signs suggestive of PPID. Pathologists described histologic findings for each section and stated whether findings were consistent with PPID. Agreement among pathologists and with antemortem diagnostic test results was calculated.

Results—Overall, only fair agreement was found among the pathologists as to which horses had histologic findings consistent with disease (mean ± SE kappa value, 0.34 ± 0.069). Interpretation of individual sections varied, with minimal agreement (4 or 5/7 pathologists) for 5 of 10 sections evaluated. Postmortem assessment was in agreement with an antemortem endocrine diagnostic test result 79% of the time.

Conclusions and Clinical Relevance—Validation of antemortem diagnostic testing for PPID in horses often relies on the results of postmortem histologic evaluation. The lack of consensus in histologic interpretation of pituitary glands from aged horses with mild clinical signs in our study indicates that postmortem histologic evaluation of pituitary glands is an inappropriate standard in validation of antemortem diagnostic tests for detection of early PPID. Caution should be used when interpreting diagnostic test results in horses in which early PPID is suspected. (Am J Vet Res 2005;66:2055–2059)

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in American Journal of Veterinary Research

Abstract

Objective—To standardize techniques for renal scintigraphy in birds, to use scintigraphy to assess gentamicin nephrotoxicosis in birds, to compare nuclear medicine assessments with histologic assessment of gentamicin nephrotoxicosis and serum uric acid concentrations, and to determine the radiopharmaceutical that best quantifies avian renal function.

Animals—12 domestic pigeons (Columba livia domestica).

Procedure—Serum uric acid concentrations were determined for all birds. Renal scintigraphy techniques that used technetium-m99 (99mTc)-dimercaptosuccinic acid (DMSA; 4 hours after injection) and 99mTc-diethylenetriamine pentaacetic acid (DTPA; 15- minute dynamic study) were evaluated in all birds. Renal biopsy specimens were collected following baseline scans. Number and size of renal tubule granules positive for periodic acid-Schiff stain were scored for severity (scale of 0 to 4). Nephrotoxicosis was induced by administration of gentamicin. Serum uric acid concentrations were measured, and 99mTc-DMSA and99mTc-DTPA scans were repeated after gentamicin administration. Birds were euthanatized, and complete necropsies were performed.

Results—Standard avian renal scintigraphy techniques were developed for 99mTc-DMSA and 99mTc- DTPA. Decreased renal radiopharmaceutical uptake for 99mTc-DMSA and 99mTc-DTPA indicated nephrotoxicosis. Cloacal accumulation of 99mTc-DTPA was significantly decreased after administration of gentamicin. Histologic grading of renal tissue before and after gentamicin administration confirmed nephrotoxicosis. Inconsistent serum uric acid concentrations could not be used to assess nephrotoxicosis.

Conclusions and Clinical Relevance—Renal nuclear scintigraphy is a useful, noninvasive means to determine renal function in birds. Although 99mTc-DMSA may prove useful in the evaluation of renal morphology, 99mTc-DTPA is the radiopharmaceutical agent of choice for the assessment of renal function in avian species. (Am J Vet Res 2003;64:453–462)

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in American Journal of Veterinary Research

Abstract

Objective—To characterize the clinical, clinicopathologic, and imaging findings in dogs with intestinal lymphangiectasia and to compare the histologic grade of lymphangiectasia with clinicopathologic and imaging abnormalities.

Design—Retrospective study.

Animals—17 dogs with a histologic diagnosis of intestinal lymphangiectasia.

Procedure—Medical records of dogs with a histologic diagnosis of intestinal lymphangiectasia were reviewed for signalment, history, clinical signs, results of exploratory laparotomy, and clinicopathologic, radiographic, ultrasonographic, and histologic findings.

Results—Mean age of dogs was 8.3 years; the most common clinical signs were diarrhea, anorexia, lethargy, vomiting, and weight loss. Abnormal physical examination findings included dehydration, ascites, and signs of pain on palpation of the abdomen. The most notable clinicopathologic findings were low serum ionized calcium concentration and hypoalbuminemia. Abdominal ultrasonography was performed in 12 dogs and revealed intestinal abnormalities in 8 dogs and peritoneal effusion in 7 dogs. Exploratory laparotomy revealed abnormalities in 9 of 16 dogs including thickened small intestine, dilated lacteals, lymphadenopathy, and adhesions. On histologic examination of the small intestine, concurrent inflammation was observed in 15 of 17 dogs, crypt ectasia in 5 of 17, and lipogranulomas in 2 of 17.

Conclusions and Clinical Relevance—Intestinal lymphangiectasia in dogs appears to be a heterogeneous disorder characterized by various degrees of panhypoproteinemia, hypocholesterolemia, lymphocytopenia, and imaging abnormalities. In most dogs, the severity of hypoalbuminemia appears to offer the best correlation with severity of histologic lesions of lymphangiectasia. Imaging abnormalities are common in dogs with intestinal lymphangiectasia but are not specific enough to differentiate this disorder from other gastrointestinal disorders, nor are they predictive of histologic severity. (J Am Vet Med Assoc 2001;219:197–202)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine which imaging modality best determines the microscopic extent of primary appendicular osteosarcoma in amputated limbs in dogs.

Design—Case series.

Animals—10 dogs with appendicular osteosarcoma.

Procedure—10 dogs with appendicular osteosarcoma that did not receive neoadjuvent chemotherapy were treated by use of limb amputation. Amputated limbs were imaged by use of radiography, computed tomography (CT), and magnetic resonance imaging (MRI) and examined microscopically to determine longitudinal extent of neoplastic cell involvement and length of associated intramedullary fibrosis. Changes detected by use of the various imaging studies were compared with the actual tumor length determined microscopically. Data were analyzed to determine which imaging technique most closely predicted tumor length.

Results—Measurements obtained by use of craniocaudal radiographic views were most accurate at predicting tumor length but underestimated tumor length substantially in 1 limb and slightly in another limb. Measurements made by use of CT were most accurate at predicting tumor length when intramedullary fibrosis was taken into account but underestimated tumor length in 1 limb. Measurements made by use of MRI were least accurate but did not underestimate tumor length in any of the limbs.

Conclusions and Clinical Relevance—Although radiography is used in diagnosis of osteosarcoma in dogs, additional imaging studies to confirm the extent of neoplasia prior to limb-sparing ostectomy may be beneficial. Underestimation of tumor length would be associated with higher incidence of incomplete excision and local tumor recurrence. (J Am Vet Med Assoc 2002;220:1171–1176)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether severity of leukocytosis correlates with severity of postmortem lesions in dogs with immune-mediated hemolytic anemia (IMHA).

Design—Retrospective study.

Animals—34 dogs with IMHA that had CBC performed within 48 hours prior to death and complete necropsy examinations.

Procedure—Dogs were independently assigned to 4 leukocytosis groups (within reference range; mild leukocytosis, moderate leukocytosis, marked leukocytosis) and 3 lesion severity groups (mild lesions, moderate lesions, severe lesions).

Results—Moderate to marked leukocytosis correlated with moderate to severe postmortem lesions. Ischemic necrosis within liver, kidney, heart, lung, and spleen attributable to thromboembolic disease or anemic hypoxia were the most common important lesions found at necropsy. None of the dogs with mild lesions had moderate or marked leukocytosis. Four of 14 severely affected dogs had WBC counts within reference range, but all 4 had neutrophilic left shifts. Three of these 4 dogs had toxic change in neutrophils.

Conclusion and Clinical Relevance—Moderate to marked leukocytosis, neutrophilic left shift, and toxic change in neutrophils in dogs with IMHA should alert clinicians to the potential for moderate to severe tissue injury, which could complicate treatment and worsen prognosis. Lesions appear to be secondary to anemic hypoxia, thromboembolic disease, or both; therefore, treatment objectives should focus on improving blood oxygen-carrying capacity and monitoring for thromboembolic disease. (J Am Vet Med Assoc 2001;218:1308–1313)

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association