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Abstract

Objectives

To describe expression of the neuroendocrine marker chromogranin A (CgA) in canine and feline pancreatic islet cell tumors and their metastases, and to evaluate plasma CgA concentration in dogs and cats with insulinoma.

Sample Population

Paraffin-embedded tissues from 25 canine and 2 feline pancreatic islet cell tumors, 5 canine and 6 feline exocrine pancreatic tumors, and normal pancreatic tissue from 2 dogs and 2 cats. Heparinized plasma samples from 3 dogs and 2 cats diagnosed with insulinoma, and 10 control plasma samples from each species.

Procedure

Immunohistochemical analysis was performed on the 42 tissue specimens, using antisera against CgA, neuron-specific enolase, insulin, somatostatin, glucagon, and pancreatic polypeptide. The 25 plasma samples were evaluated, using a soluble-phase, double-antibody, equilibrium radioimmunoassay directed against the amino- and carboxy-terminal peptides of bovine CgA.

Results

Chromogranin A expression was found in 76% of canine and 2 of 2 feline pancreatic islet cell tumors. Of 7 animals with CgA immunoreactivity in primary tumors, 6 also had CgA immunostaining of metastatic lesions. Plasma CgA concentration in 2 dogs with insulinoma (0.9, 1.0 ng/ml) exceeded the reference range established for 10 clinically normal control dogs (0.50 ± 0.16 ng/ml). Feline plasma CgA samples had extensive nonspecific background immunoreactivity.

Conclusions

Chromogranin A is a useful immunohistochemical marker for pancreatic tumors of neuroendocrine origin and their metastases. Plasma CgA concentration determined by radioimmunoassay was high in 2 dogs with insulinoma.

Clinical Relevance

Immunohistochemical staining of tissues or cytologic specimens for CgA and/or neuron-specific enolase may help distinguish masses of unknown origin as neuroendocrine in nature. Increase in plasma CgA concentration may be useful diagnostically for animals with suspected neuroendocrine tumors. (Am J Vet Res1997;58:615–620)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To characterize factors that affect solid-phase gastric emptying in healthy cats by use of nuclear scintigraphy and to assess differences in emptying patterns of dry and canned diets.

Animals

20 healthy cats.

Procedure

2 groups of 10 cats each were fed dry or canned diet for at least 2 weeks before scintigraphy was done. Diets were labeled with 99mTc-disofenin. After ingestion of labeled meals, scintigraphic images were obtained at 0, 15, 30, 45, and 60 minutes, then every 30 minutes to 6 hours. Gastric emptying scans were obtained 3 times for each cat for each diet, in a complete crossover design. The T90, T50, and T20 (times when 90, 50, and 20% of initial meal activity remained in the stomach, respectively) were derived from gastric emptying curves fit to nonlinear models. A mixed models approach was used for data analysis.

Results

Gastric emptying was well described by a nonlinear model. Meal size, water intake, and diet type significantly (P < 0.05) effected gastric emptying. The T90, T50, and T20 increased with meal size, regardless of diet type or water intake. Gastric emptying of a dry diet meal took significantly (P < 0.05) longer than that of an isocaloric meal of canned diet, except when meal size was small. Differences in gastric emptying of dry and canned diets varied with the phase (T90 vs T50 vs T20) of emptying.

Conclusion

Water intake, meal size, and diet type significantly influence gastric emptying in healthy cats, and these factors must be considered in analysis of gastric emptying data. (Am J Vet Res 1998;59:388–392)

Free access
in American Journal of Veterinary Research