Additional details of the life history of the chicken coccidium Eimeria mitis Tyzzer, 1929

Four asexual generations of Eimeria mitis were identified. The first three developed above the epithelial cell nuclei, but the fourth developed above and below. Meronts measured 13.8 x 16.4 microns, 16.1 x 16.4 microns, 12.1 x 14.6 microns, and 9.5 x 12.4 microns, respectively, of generations 1, 2, 3, and 4. They matured at 36, 67, 72, and 88 hr postinoculation (PI) and contain 20-24, 16-20, 10-14, and 7-10 merozoites, respectively. Merozonts measured 7.2 x 1.9 microns, 8.5 x 2.5 microns, 9.6 x 2.0 microns, and 6.75 x 2.75 microns, respectively. The first two types of meronts were deep in the crypts and epithelial cells. The third and fourth types of meronts were along the side and tip of the villi. Gametocytes developed from third and fourth generation. Gamonts were usually below the nuclei of the epithelial cells. Parasitism was primarily in the ileum, ceca, and rectum and also in the yolk-sac diverticulum.     

Experimental rodent models of brainstem tumors

Despite recent advances in surgical technology, resection is not an option for many brainstem tumors. Experimental models have played essential roles in examining new approaches to therapy. The objective of the present study was to generate models by determining coordinates for safe inoculation into the brainstem of mice and rats, and to establish whether the implantation of heterotopic cells would create reproducible survival curves. Morbidity and survival studies were used to map stereotactic coordinates allowing successful inoculation of tumor cells. Survival studies were used to investigate the time course of tumor growth. Tumor location was examined by light microscopy and magnetic resonance imaging. Mice survived injections of 2 microL of saline at interaural, lateral, and depth coordinates of -2.5, 1.0, and 3.5 mm and -1.5, 1.0, and 3.5 mm. Rats survived injections at interaural, lateral, and depth coordinates of -2.0, 2.0, and 7.0 mm and -3.0, 0, and 7.0 mm. Median survival of mice challenged with 5 x 10(5) EMT6 and 10(4) B16 tumor cells was 11 and 10 days, respectively. Median survival for rats challenged with 10(4) 9L and F98 cells was 14 and 13 days, respectively. The present study demonstrates a feasible approach to preparing models of brainstem tumors. Limitations of these models are discussed.     

Synovial sarcoma of the tendon and tendon sheath in a dog

A 19.5-year-old male mongrel dog developed a progressive lameness and swelling around the right carpus. A tumor (6 x 3 x 3 cm) was found in the caudal of distal antebrachium of the right forelimb, including tendons of the superficial digital flexor muscle and deep digital flexor muscle. No joint destruction was observed. The tumor consisted of round and spindle cells arranged in a compact sheet. There were occasional slit-like spaces or lumina, and areas rich in collagen fibers giving an appearance of tendon tissues. Neoplastic cells gave a positive immunoreaction to vimentin, but negative reactions to antibodies against S-100 protein, cytokeratin and myoglobin. Based on these findings, this tumor was diagnosed as a synovial sarcoma generating from the tendon and tendon sheath, which is very uncommon in dogs.     

Gastric pleomorphic leiomyosarcoma in a Shetland sheepdog

A solitary mass of 6 x 6 x 5 cm was found in the smooth muscle layer of the pyloric part in the stomach of a Shetland sheepdog. The excised mass was solid, gray-white in color, and had central necrosis with hemorrhages. Microscopically, the neoplasm was composed of irregular bundles of spindle-shaped tumor cells and round tumor cells. A few multinucleated cells and gangliocyte-like cells were observed. The nuclei exhibited a high degree of atypia and many cells contained mitotic figures. Immunohistochemically, tumor cells were positive for vimentin and desmin, but negative for c-kit antibody. Ultrastructurally, tumor cells contained cytoplasmic myofilaments and pinocytotic vesicles. Based on these pathological findings, the tumor was diagnosed as gastric pleomorphic leiomyosarcoma.     

Malignant peripheral nerve sheath tumor as a cause of chronic cardiac insufficiency in cattle

Chronic cardiac insufficiency was associated with a malignant peripheral nerve sheath tumor in a cow. An eight-year-old cow developed a progressive condition (over a period of three months) characterized by an enhanced abdominal volume, reluctance to move, a positive jugular pulse, watery diarrhea and death. At necropsy, moderate subcutaneous edema and an enhanced hepatic lobular pattern were observed. A 23x20x11 cm firm, grayish-white mass adhered to and infiltrated the right atrium. Multiple firm, yellowish-white nodules of 0.5 to 12 cm in diameter were diffusely scattered in the epicardium and parietal pericardium. Histologically, the tumor was poorly circumscribed with foci of infiltration of the myocardium. The neoplastic cells had two major histologic patterns, Antoni types A and B. Within occasional foci, pleomorphic cells with an epithelioid appearance were present in addition to multinucleated cells with periodic acid Schiff (PAS)-positive cytoplasmic globules. Foci of cartilaginous and granular differentiations were interspersed among the neoplastic cells. Multiple vessels presented wall hyalinization and tumoral embolus. Large necrotic foci with mineralization and cholesterol clefts were also observed. Immunohistochemically, the tumor was positive for S100 protein, vimentin and neuron-specific enolase labeling.     

Intracranial granular cell tumor in a dog

A 12-year-old female miniature poodle showed a 3-month history of neurological signs. Magnetic resonance imaging disclosed a high intensity tumor mass in the right cerebral hemisphere with compression of the lateral ventricle. At necropsy, a 2 x 3 cm white, friable mass was found in the right ventral pyriform lobe. Microscopically, the tumor cells were large, polygonal to round cells supported by a sparse fibrovascular stroma. The tumor cells typically possessed finely granular, pale eosinophilic cytoplasm with strongly positive periodic acid-Schiff (PAS) reaction. The tumor cells were immunopositive for vimentin, NSE and S-100. Ultrastructurally, the tumor cells showed large amounts of granules in the cytoplasm, and absence of basement membrane. Based on the above-mentioned findings, the intracranial granular cell tumor was diagnosed.     

Antibody response of calves after intranasal inoculation with parainfluenza-3 virus and resistance of inoculated calves to experimental homologous viral infection

The immunologic response of colostrum-deprived calves to parainfluenza-3 (PI-3) virus given by intranasal inoculation was studied. Inoculation of calves with 3.2 x 10(6) median cell culture infective doses (CCID50) of either virulent (SF-4) virus or a modified strain of PI-3 virus, or with 2.0 x 10(8) CCID50 of SF-4 virus, stimulated development of both serum antibody and nasal secretion (NS) antibody. However, NA antibody decreased in all calves between the 16th and 42nd postinoculation days and was present only at low or moderately low concentrations on the 126th day, when the immunity of the calves was challenged. Generally, calves that were inoculated with 3.2 x 10(6) CCID50 of SF-4 virus developed slightly higher concentrations of serum and NS antibodies than did calves inoculated with modified virus. Calves that were inoculated with 2.0 x 10(8) or 3.2 x 10(6) CCID 50 of SF-4 virus developed comparable concentrations of serum antibody, but large doses of SF-4 virus were less effective than smaller doses of the same virus in stimulating the development of NS antibody. Reinoculation of 3 calves with modified PI-3 virus resulted in a demonstrable increase in serum antibody in 2 calves and an increase and subsequent decrease in NS antibody in all calves. Challenge exposure of inoculated calves to aerosols of SF-4 virus failed to cause clinical signs of disease, and the challenge virus was not isolated from the nasal passages.     

Immunocytochemical identification of neoplastic cell clone in phase S of cell cycle in transplantable rat tumors

Wistar and Buffalo rats of both sexes, aged 4 months, were divided into three groups: I which was given an intramuscular injection of 3 x 10(6) cells of Morris hepatoma (Buffalo males), II--subcutaneous injection of 3 x 10(4) cells of mammary gland carcinoma (Wistar females), III--intraperitoneal injection of 3 x 10(4) cells of Yoshid sarcoma (Wistar males). The animals were killed: in group I--19, group II--13 and in group III--6 days after tumor transplantation. Twenty four hours before euthanasia the rats were given 5-brome-2'-deoxyuridine (BRd-U) at a dose of 50 mg/kg body mass. The control group consisted of animals with tumour. They were not treated with BRd-U. Immunocytochemical reaction was performed on the sections of tumors, using monoclonal anti-BRd-U clone BU-33, Sigma. Computer measurements of tumor cells were carried out. There was a high similarity in morphological parameters between two kinds of cancer, and clear differences between them and Yoshid sarcoma. The main difference was noted in a twofold increase in the quantity of synthesised DNA in the nuclei of sarcoma cells. Immunocytochemical identification of tumor cells in phase S of the cell cycle with the use of monoclonal anti-BRd-U antibody is a precise and quick method of estimation of their proliferative potential.     

Myxoid leiomyosarcoma of the gizzard in a broiler chicken

A leiomyosarcoma was found in the gizzard of a 57-day-old female broiler chicken weighing 1.8 kg. Grossly, the tumor mass, 13.0 x 8.5 x 10.0 cm, enveloped the gizzard and had a gelatinous appearance due to the rich production of mucin. Miliary metastatic tumors were noted in the liver. Histopathologically, there was marked production of mucus throughout the tumor tissue, and densely or loosely arranged long spindle-shaped leiomyosarcoma cells proliferated. The tumor cells had a low rate of mitosis, showed slight cellular atypia, and, immunohistochemically, were positive for actin, alpha-smooth muscle actin, and desmin. Electron microscopically, various amounts of microfibrils with focal densities, dense patches, and basal plates were observed.     

Omental leiomyoma in a male adult horse

A well-circumscribed mass 70 x 35 x 28 cm in size and 41 kg in weight was detected at necropsy in a male adult horse within the omentum major without any association to the gastrointestinal tract. The tumor consisted of multiple white-to-yellow lobules and displayed a firm consistency. In addition, multiple cysts filled with blood-like fluid, and multifocal areas of necrosis were observed. Histologically, the mass consisted of slightly pleomorphic spindloid-shaped cells arranged in interlacing bundles containing elongated nuclei with blunt ends. The majority of tumor cells revealed a positive immunoreaction for alpha-smooth muscle actin, vimentin, and neuron-specific enolase and were negative for S-100, factor VIII-related antigen, and glial fibrillary acidic protein. Few tumor cells showed expression of desmin and c-kit. On the basis of macroscopy, histology, and immunohistochemistry, an omental leiomyoma was diagnosed.     

Cardiomyopathy associated with angiomatous pheochromocytoma in a rhesus macaque (Macaca mulatta)

A 24-year-old female rhesus macaque (Macaca mulatta) presented with a clinical history of chronic heart disease and prolonged recovery from sedation and anesthesia. At necropsy, the heart was markedly enlarged, with thinned ventricular walls, dilated chambers, and severe left atrioventricular valvular insufficiency. The ventricular walls contained numerous narrow, pale, often coalescing streaks that often extended along vessels into the deeper myocardium. Histologically, bands of interstitial fibrosis in the heart were associated with areas of myofiber atrophy, myofibril degeneration and loss, and inflammation. The left adrenal gland contained a 2 x 1 x 0.5 cm tumor with an unusual angiomatous pattern consisting largely of blood-filled sinusoids lined by one to four layers of low cuboidal to polyhedral tumor cells. In most sinusoids, the tumor cells appeared to be in direct contact with blood, although endothelial cells lined some sinusoids. Ultrastructurally, the tumor cells contained abundant electron-dense cytoplasmic granules. These granules were argyrophilic by Sevier-Munger staining and intensely immunoreactive for synaptophysin, chromogranin A, neuron-specific enolase, and S-100. These findings helped confirm the diagnosis of angiomatous pheochromocytoma. The heart lesions match those reported for catecholamine cardiomyopathy in other species.     

Glomus tumor in the digit of a cat

A solitary mass approximately 1.5 x 2 cm located on the outer side of the third digit of the left forepaw of a 7-year-old male cross-breed cat was examined pathologically. The excised tumor mass was hard and white and located within the deep dermis and subcutis. Histopathologically, the mass consisted of a mixed population of small round epithelioid cells arranged in ribbon- or cordlike structures and spindle-shaped cells forming loose irregular bundles in a mucinous stroma. The epithelioid cells were often arranged around small blood vessels. Neoplastic cells were intensely positive for vimentin and alpha smooth muscle actin and negative for keratin, desmin, S-100 protein, and neuron-specific enolase. Based on these pathologic features, the tumor was diagnosed as a glomus tumor, a neoplasm not previously reported in cats and extremely rare in animals.     

Mediastinal plasma cell tumor in a sheep

An extramedullary plasmacytoma was found in a 10-year-old sheep. The tumor involved the mediastinum, where a 25 x 15 x 10-cm encapsulated mass was found. The lungs had multiple metastases ranging from 0.5 to 2 cm in diameter, and the portal vein contained a 10-cm-long mass. The cytologic and histopathologic analyses were consistent with a moderately differentiated plasmacytoma. The immunophenotype of the tumor cells was lambda light chain IgG+, CD79a-, and CD3-. Occasional granulomas were observed at the periphery of the mediastinal and pulmonary tumors. Microbiologic culture yielded growth of Corynebacterium from these granulomas. This is the first report of plasmacytoma in sheep. The tumor most likely arose from mediastinal lymph nodes and metastasized to the lungs and portal vein.     

A pleomorphic adenoma of the lacrimal gland in a dog

A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.     

A solid mature teratoma of a feline ovary

A 17-year-old female crossbred cat developed a mass on the left ovary. The mass was solid, firm, 5.5 x 3.5 x 4.5 cm. The mass contained ectodermal components (skin and appendages), mesodermal components (osseous, cartilaginous and adipose structures), and endodermal components (glandular structures lined by columnar epithelium). The tumor was diagnosed as a solid, mature teratoma of the ovary.     

Osteoclast-like giant cell tumour arising from the kidney in a dog

In this study, a case of osteoclast-like giant cell tumour arising from the kidney is reported in an eight-year-old female Anatolian Shepherd dog. Macroscopically, the tumorous mass covered the hilus of the left kidney. It was 26 x 22 x 12 cm in size and 3700 g in weight. Metastatic tumorous nodules, 0.5-2.0 cm in diameter, were found on the abdominal side of the diaphragm and in the lungs. Microscopically, numerous large osteoclast-like multinucleated giant cells and spindle-spheroidal-shaped cells were seen. Osteoblastic differentiation and osteoid matrix were noted in a few areas at the periphery of the tumour, near the connective tissue septa. The stroma of the tumour tissue was vascular, oedematous and loose. By immunoperoxidase staining, tumour cells showed immunoreactivity for vimentin but not for keratin and desmin, indicating that the tumour had mesenchymal origin. This is the first report in the literature on a malignant osteoclast-like giant cell tumour arising from a visceral organ in animals.     

Malignant fibrous histiocytoma (giant cell type) associated with a malignant mixed tumor in the salivary gland of a dog

A 12-year-old male Boxer dog presented with a 5 x 5 x 7-cm partially encapsulated mass in the right mandibular salivary gland. Histologically, the mass was composed of neoplastic epithelial and mesenchymal cells. The mesenchymal component consisted of two cell populations arranged in different patterns: coalescing nodules of neoplastic mononuclear cells with rare osteoid and numerous osteoclastlike giant cells; and sheets of neoplastic spindle cells intermingled with neoplastic epithelial cells and containing osteoid and well-formed bone trabeculae lined by osteoblasts and few osteoclastlike giant cells. On the basis of these histological features, two malignant salivary tumors were diagnosed: a malignant fibrous histiocytoma (giant cell type) and a malignant mixed tumor. Immunohistochemical studies demonstrated keratin 5 and 8 expression by the neoplastic epithelial cells, indicating a probable salivary ductal origin, and vimentin expression by all mesenchymal elements, suggesting a fibroblastic line of differentiation.     

Extra-adrenal pheochromocytoma (paraganglioma) in a cat

Extra-adrenal pheochromocytoma (paraganglioma) arising from periadrenal tissue was diagnosed in an 18-year-old spayed domestic shorthair cat. The tumor was palpable on physical examination, but not apparent on plain radiographs. The cat developed temporary cardiac arrhythmia while the mass was being handled during excision, suggesting that the tumor was functional. The tumor was characterized histologically by nests and sheets of neoplastic cells separated by thin, vascular stroma. The cells had abundant eosinophilic granular cytoplasm and prominent nuclei. Diffuse, dark, intracytoplasmic granules were seen in sections stained with Grimelius stain. Ultrastructurally, the cells contained round and oblong, membrane-limited, dense core neurosecretory-type granules. Serotonin was detected in the cytoplasm of the neoplastic cells by use of immunocytochemical analysis.     

Myofibroblastoma of the neck in a heifer

A 1.5-year-old Holstein heifer had a subcutaneous tumor mass (20 cm diameter) on the ventral portion of the neck, and the tumor was diagnosed as a locally invasive myofibroblastoma. It consisted of moderately cellular fibrous tissue, and the interlobular septum of the thymus was invaded by tumor cells. The neoplastic cells were positive for alpha smooth muscle actin and vimentin, but not for desmin. Electron microscopy disclosed the presence of moderately developed rough endoplasmic reticulum and microfilaments with focal densities.     

The association between quarter somatic-cell counts and clinical mastitis in three British dairy herds

The association between quarter somatic-cell counts (QSCCs) of milk and the risk of clinical mastitis (CM) was investigated in a 1-year study on three dairy herds in Somerset, UK. The three herds had 95-130 milking cows and an annual mean bulk milk somatic-cell count (BMSCC) of <150 x 10(3)cells/ml. The farms were visited every 4-6 weeks at morning milking when quarter-milk samples were collected. The farmers recorded all cases of CM and were trained to collect sterile milk samples from affected quarters, before treatment for bacteriology.The three herds had CM incidence rates of 25.4, 55.2, and 67.6 quarter-cases per 100 cow-years. Escherichia coli and Streptococcus uberis were cultured from approximately 50% of cases. QSCC was categorised and the risk of CM occurring in the month after the QSCC was examined using multilevel models to account for the correlated nature of the dependent data. Three models were developed: one for all cases of CM, one for those caused by coliforms and one for those caused by S. uberis. When all cases of CM were considered, quarters with somatic-cell count (SCC) 21-100 x 10(3)cells/ml had reduced odds (OR=0.60, P=0.06) and quarters with SCC >200 x 10(3)cells/ml has over three time the odds (OR=3.7, P<0.01) of CM compared with QSCC 1-20 x 10(3)cells/ml. When only coliform CM were investigated, quarters with SCC 6-200 x 10(3)cells/ml had reduced odds of coliform CM (OR=0.47, P=0.04) compared with QSCC 1-5 x 10(3)cells/ml, and SCC >200 x 10(3)cells/ml were not significantly different from the baseline. Finally, when S. uberis CM were investigated, quarters with SCC >200 x 10(3)cells/ml had more than three times the odds of S. uberis CM compared with QSCC 1-20 x 10(3)cells/ml (OR=3.73, P<0.01). QSCC <21 x 10(3) and >200 x 10(3)cells/ml are associated with increased odds of CM in the following 4-6 weeks; this association may be pathogen specific.