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  • Author or Editor: Lluis Ferrer x
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Abstract

Objective—To evaluate molecular abnormalities in the c-kit gene of canine mast cell tumors (MCT) with different grades of cellular differentiation.

Sample Population—31 normal tissue specimens from dogs and 45 canine MCT classified according to grade of cell differentiation.

Procedure—Genomic DNA extractions were made from canine MCT and normal tissues. Parts of exon 11, intron 11, and exon 12 of the c-kit gene were amplified by use of polymerase chain reaction. These regions were cloned, sequenced, and compared with GenBank sequences of the National Center for Biotechnology International. A statistical analysis was used to compare sequences from canine MCT and normal tissues.

Results—A significantly higher percentage of homozygous intron 11 deletion was found in canine MCT (49%) than in normal tissues (13%). This percentage was also higher in moderately and poorly differentiated MCT, compared with well-differentiated MCT. Although no mutations were detected in any of the specimens, a polymorphism at amino acid position 606 of the canine c-kit sequence was found in all the studied sequences.

Conclusion and Clinical Relevance—Results indicated a relationship between intron 11 deletion and MCT, and the grade of MCT differentiation. We suggest that intron 11 deletion may be implicated in the pathogenesis of MCT and could be used as a marker for diagnosis and prognosis of canine MCT. (Am J Vet Res 2002;63:1257–1261)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether high-frequency diagnostic ultrasonography is useful for assessment of skin thickness in Shar-Peis.

Animals—10 healthy Shar-Peis and 10 healthy Beagles used as controls.

Procedures—Ultrasonographic examination of the skin was performed on 4 cutaneous sites by use of a 13-MHz linear-array transducer, and the mean of 3 measurements was calculated. Ultrasonography results were compared with histologic findings of skin specimens stained with H&E, Alcian blue at a pH of 2.5, and Masson trichrome stains, with histometric measurements of skin thickness made by use of a microscope, and with measurements of skin thickness made by use of a plicometer. Ultrasonograpy results were also compared via age and sex of selected animals.

Results—A clear correlation was detected between ultrasonography results and results of histologic and histometric analysis in both groups. In Shar-Peis, no correlation was found between ultrasonography results and age and sex, whereas in Beagles, a weak positive correlation was found only between skin thickness in dorsal cervical and frontal (on the rostral margins of the supraorbital processes) regions and age. A positive overall correlation was found in Shar-Peis between measurements made via ultrasonography and plicometery.

Conclusions and Clinical Relevance—Ultrasonography was a useful tool to assess skin thickness, and in Shar-Peis, it might be considered a valid alternative to invasive methods such as histologic examination to objectively estimate the severity of hereditary cutaneous hyaluronosis.

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in American Journal of Veterinary Research
in Journal of the American Veterinary Medical Association

Abstract

Objective—To assess expression and function of cellsurface IgE receptors on the canine mastocytoma cell line C2 maintained in continuous culture.

Sample Population—C2 cells maintained in medium lacking IgE for up to 10 passages before being stored at –80 C.

Procedure—Cells were thawed, cultured in medium without IgE for 1 to 3 passages, sensitized for 7 days with IgE-rich serum from dogs naturally sensitized to Ascaris suum, and stimulated with antigen Asc S1 from A suum, goat polyclonal anti-canine IgE, or calcium ionophore and phorbol myristate acetate (PMA). Percentage of intracellular β-hexosaminidase released and concentration of tumor necrosis factor-α (TNF-α) synthesized after stimulation were determined. Expression of cell-surface IgE receptors was assessed by use of a flow cytometry.

Results—Immunologic stimulation (antigen or anti-IgE) failed to induce release or synthesis of detectable amounts of β-hexosaminidase or TNF-α. In contrast, nonimmunologic stimulation (calcium ionophore and PMA) led to release of β-hexosaminidase (mean ± SEM maximum release, 23.95 ± 1.96%) and synthesis of TNF-α (maximum concentration, 34.34 ± 2.34 pg/106 cells). As revealed by use of flow cytometry, C2 cells expressed surface IgE receptors that bound canine IgE in vitro.

Conclusions and Clinical Relevance—Continuous culture of the canine mastocytoma cell line C2 in medium without exogenous IgE or cytokines and other growth factors resulted in cell-surface expression of nonfunctional IgE receptors. However, C2 cells maintained in continuous culture may still be a useful tool for the evaluation of mast cell responses to nonimmunologic stimulation and IgE receptor differentiation and maturity. (Am J Vet Res 2002;63:763–766)

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in American Journal of Veterinary Research

Abstract

Objective—To characterize eosinophil granulederived proteins in cats.

Sample Population—Eosinophils collected via peritoneal lavage from 2 cats.

Procedure—The cats were infested orally with Toxocara canis eggs and subsequently challengeexposed with T canis antigen injected IP to induce peritoneal eosinophilia; eosinophils were collected via peritoneal lavage. Eosinophil granule proteins were acid-extracted, separated by gel-filtration chromatography, and examined for their peroxidase, ribonuclease, and bactericidal activities; the N-terminal sequence of some of these proteins was determined and compared with homologue proteins from other species.

Results—3 protein peaks were separated in the chromatogram. The first peak had both peroxidase and bactericidal activities. The second peak had ribonuclease and bactericidal activities, and the N-terminal sequence of the major protein was homologous with that of proteins of the ribonuclease A superfamily, including eosinophil ribonucleases from humans and other animal species. The third protein peak had bactericidal activity, and the N-terminal sequence of the major protein was homologous with that of human and murine major basic proteins.

Conclusions and Clinical Relevance—Results indicated that feline eosinophil granules contain major basic protein and eosinophil-associated ribonuclease and the granule proteins have peroxidase, ribonuclease, and bactericidal activities. In cats, characterization of eosinophil granule proteins may be useful in elucidation of the mechanism of tissue damage in eosinophil-associated diseases and development of new treatment options for those diseases. In addition, the identification of conserved structure and function of eosinophil granule proteins in cats is relevant from an evolutionary viewpoint. ( Am J Vet Res 2004;65:957–963)

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in American Journal of Veterinary Research