P.J. Brown

Pathological features of lymphoid tissues in cats with natural feline immunodeficiency virus infection

Summary A range of tissues from a total of 17 cats naturally infected with the feline immunodeficiency virus was examined histologically. In 11 cases, chronic inflammatory lesions were present in various tissues including, most commonly, the intestine, brain and lung. Extensive inflammation in the intestinal wall was present in seven of the cats. No particular bacterial organisms were demonstrated in these inflammatory lesions. A range of changes was present in the lymph nodes, including hyperplasia, atrophy or a mixed pattern. Erythrophagocytosis was a consistent feature. The changes resembled those reported in human acquired immunodeficiency syndrome as a result of infection with human immunodeficiency virus.

An immunohistochemical study of canine extramedullary plasma cell tumours

Twenty-three cases of dog plasma cell tumours were investigated for the presence of monoclonal cytoplasmic immunoglobulin light chain types and heavy chain classes. The peroxidase-antiperoxidase method was applied to formalin-fixed, paraffin-embedded tissues, available as stored blocks. Twenty tumours showed a monoclonal light chain type and heavy chain class pattern, two showed a monoclonal light chain type and a biclonal heavy chain class pattern, findings which confirmed the neoplastic nature of the plasma cells. One tumour did not stain with any of the antisera. The results indicate that the method reliably establishes the monoclonality and, consequently, the neoplastic nature of plasma cell proliferations.

Histochemistry of mucins of pig intestinal secretory epithelial cells before and after weaning

Two histochemical staining techniques, Alcian blue/PAS and high-iron-diamine/Alcian blue, which differentiated neutral from sulphated and sialylated acid mucins were applied to sections of duodenum, ileum, caecum, colon and rectum from pigs aged one day, 3 weeks and 10 weeks. In each age group, sulphated-acid mucins predominated at all sites, particularly in the large intestine. In both the small and the large intestine, non-sulphated mucins occurred mainly at the bases of the crypts. Neutral mucins occurred in a few goblet cells in crypts and villi, either alone or together with acid mucins; neutral mucins increased away from the bases of the crypts. No changes were noted in the caecum, colon or rectum of pigs one, two, 5 or 13 days after weaning onto a diet containing soya protein. In the small intestine, there was a transient increase in the numbers of goblet cells in the crypts and villi, a relative increase in sulphated and a decrease in non-sulphated acid mucins and a change in the distribution of sulphated mucins in the crypts. No change in proportions of neutral and acid mucins was detected.

Immunohistochemical staining of neoplastic and inflammatory plasma cell lesions in feline tissues

Two cases of feline plasmacytoma and nine cases of reactive plasma cell proliferations were examined for the presence of cytoplasmic immunoglobulin light chain types and heavy chain classes, by the peroxidase-anti-peroxidase technique on sections of formalin-fixed, paraffin-embedded tissues. This immunohistochemical technique is an important aid to conventional histological techniques. It helps to differentiate between neoplastic and dense inflammatory plasma cell proliferations by determining the presence of one, or more than one, light chain types in the cells, which corresponds with their neoplastic or reactive nature.

A testicular seminoma in a rabbit

The histological, ultrastructural and biological features are described of a spontaneously occurring seminoma in the testis of a male domestic rabbit. The tumour was structurally similar to seminomas in other animal species.

Hamartomatous Polyps in the Intestine of Two Dogs

Partly obstructing, proliferative mucosal masses in the small intestine of two dogs were shown histologically to be hamartomatous polyps. They were characterized by an extension of smooth muscle from the muscularis mucosae into the lamina propria of the lesion. This is the first report of such lesions in domestic animals. In one of the dogs the lesion had become malignant.

Feline necrotising sialometaplasia: a report of two cases.

Unilateral swelling of submandibular salivary gland in two cats was diagnosed as necrotising sialometaplasia. Histological features that differentiate the disease from other salivary gland lesions, particularly neoplasia are: lobular necrosis of salivary tissue; squamous metaplasia conforming to duct and/or acinar outlines; preservation of salivary lobular morphology; and variable inflammation and granulation tissue.

Ultrastructural, histochemical and immunohistochemical features of porcine intestinal lamina propria macrophages, peripheral blood monocytes and splenic adherent cells

Ultrastructural, histochemical and immunohistochemical features of porcine intestinal lamina propria macrophages (LPMs), peripheral blood fibronectin-adherent cells (FACs) and splenic-adherent cells (SPACs) were compared. Freshly isolated FACs and SPACs were small and showed small cytoplasmic processes, little evidence of endocytic vacuoles, few lysosomes and sparse rough endoplasmic reticulum (RER). Fresh FACs were negative for acid phosphatase, non-specific esterase (NSE) and beta-galactosidase activity. Of the SPACs, 20-40% were positive for acid phosphatase, < 5% for NSE and 5-10% for beta-galactosidase. Pre-cultured FACs and SPACs were large and showed an abundance of endocytic vacuoles; they possessed dilated and prominent RER and > 95% were positive for the three enzyme activities. LPMs exhibited abundant endocytic vacuoles or vesicles and lysosomes but sparse RER, and > 85% were positive for the three enzymes. LPMs (24%), FACs (49%) and SPACs (40%) expressed MHC (major histocompatibility complex) class II glycoproteins. Macrophage-granulocyte antigens were detected in LPMs (14%), FACs (50%) and SPACs (33%). The results thus suggest that freshly isolated FACs differ from LPMs morphologically and in enzymic features, and the differences may represent part of the cell maturation process.

Dysuria associated with urethral caruncle in the dog

Three cases of urethral caruncle were recognized in bitches with a history of chronic dysuria. Clinical and radiological examinations revealed the presence of inoperable lesions involving much of the urethra in all three cases. At post-mortem examination of Case 1, an oval swelling, 1.5 x 1.0 cm, was detected within the wall of the urethra close to the vagino-urethral orifice. In Case 2, firm, mottled yellow, white and red tissue formed a thickening between the urethra and vagina. In Case 3, a cylindrical cream mass, 8 cm long and 3 cm in diameter, surrounded the urethra and impinged on the wall of the vagina. Histologically, glandular structures lined by a single layer of epithelial cells and a mixed granulomatous inflammatory reaction were present in the wall of the urethra of all three cases.