Adenomatous polyp with intestinal metaplasia of the esophagus (Barrett esophagus) in a dog.

Multiple endoscopic biopsy specimens of esophageal mucosa were received from a 13-year-old castrated male standard Poodle. The dog was presented for painful swallowing. Endoscopically, the distal aspect of the esophagus was inflamed with a polypoid mass that protruded into the esophageal lumen. Histologically, the stratified squamous epithelium overlying the mass and lining the adjacent esophageal mucosa was replaced by papillary projections covered by columnar epithelium with goblet cells supported by a fibrous stroma. This article reports a case of spontaneous esophageal adenomatous polyp with intestinal metaplasia (Barrett esophagus) and reviews the pathogenesis of esophageal metaplasia and adenocarcinoma.

Anaplastic astrocytoma in the spinal cord of an African pygmy hedgehog (Atelerix albiventris).

A 2-year-old, female hedgehog presented with an 8-month history of progressive, ascending paresis/paralysis and was tentatively diagnosed with wobbly hedgehog syndrome. She died awaiting further diagnostic tests, and the owners consented to postmortem examination. Grossly, the bladder was large and flaccid and the cervical and lumbar spinal cord were regionally enlarged, light grey, and friable with multifocal hemorrhages. The thoracic spinal cord was grossly normal. Microscopically all regions of the spinal cord had similar changes, although the cervical and lumbar sections were most severely affected. These regions were completely effaced by a moderately cellular infiltration of highly pleomorphic polygonal to spindle shaped cells, mineralization, and necrosis, which were most consistent with anaplastic astrocytoma. The thoracic spinal cord white matter was similarly infiltrated by the neoplastic cells, with perivascular extension into the otherwise normal grey matter. A diagnosis of anaplastic astrocytoma was confirmed using immunohistochemical stains that were positive for glial fibrillary acidic protein and S100.

p53 expression and environmental tobacco smoke exposure in feline oral squamous cell carcinoma.

The purpose of this study was to determine the prevalence of p53 overexpression in feline oral squamous cell carcinomas (SCC) and to determine, if any, the association between p53 overexpression and lifestyle factors and environmental exposures, including exposure to environmental tobacco smoke (ETS). Questionnaires concerning exposure to ETS and other environmental factors were sent to owners of cats presenting to the Harrington Oncology Program with a diagnosis of oral SCC between 1991 and 2000. Additionally, 23 formalin-fixed biopsy samples from these cats, with information regarding ETS, were evaluated immunohistochemically for p53 expression using the CM-1 clone and the avidin-biotin-horseradish peroxidase method. Of the 23 samples evaluated, 15 (65%) showed positive nuclear staining for the CM-1 clone. Tumor biopsy samples from cats exposed to any ETS were 4.5 times more likely to overexpress p53 than were tumors from unexposed cats (P = 0.19). Among cats with any ETS exposure, those with 5 years or longer of exposure were 7.0 times more likely to overexpress p53 (P = 0.38). Longhaired cats (P = 0.18) and female cats (P = 0.35) were also more likely to show p53 expression in their tumors. These results provide additional support for a relationship between oral SCC development and exposure to household ETS and may implicate p53 as a potential site for carcinogen-related mutation in this tumor.

Chylothorax and chylous ascites in a dog with mediastinal lymphangiosarcoma.

A 10-year-old, male toy poodle presented for evaluation of a progressively worsening, harsh, nonproductive cough. Chylous pleural effusion, lymphopenia, thrombocytopenia, normoblastemia, and recurrent subcutaneous bruising were diagnosed. Surgical exploration of the cranial mediastinum revealed extensive, redundant connective tissue which was confirmed by histopathology to be mediastinal lymphangiosarcoma (LAS). During surgical placement of a fenestrated silastic mesh for passive pleuroperitoneal drainage, chylous ascites also was diagnosed. The patient was euthanized two days postoperatively due to persistent chylothorax. The etiopathogenesis of chylothorax and chylous ascites are discussed. Previous case reports of lymphatic endothelial neoplasia are reviewed.

Vascular supply of the tendon of the equine deep digital flexor muscle within the digital sheath.

The vascular and microvascular anatomy of the equine deep digital flexor tendon (DDFT) within the digital sheath was studied by injecting the vasculature with either colored latex or barium sulphate for radiographic, microangiographic, histologic, and computed tomographic (CT) evaluation. Consecutive 4-mm thick two-dimensional CT slice data were reconstructed to 3-dimensional volumetric images to enhance spatial evaluation of the blood supply. Gross dissection and angiographic studies identified three major vascular sources. Above the fetlock, the DDFT was supplied by either a branch of the medial palmar artery (Arteriae digitalis palmaris communis II) or a branch of the medial palmar digital artery (A. digitalis [palmaris propria III] medialis). Below the fetlock, the DDFT was supplied by branches from the lateral and medial palmar branches to the proximal phalanx (Ramus palmaris phalangis proximalis). The most distal aspect of the tendon received small branches from the medial and lateral palmar digital arteries. Using histology and microangigraphy we observed an extensive and uniform intratendinous vascular network above and below the fetlock, with a relatively avascular region of tendon palmar to the fetlock. The most distal 2.0 to 2.5 cm of the tendon within the sheath was heavily infiltrated with fibrocartilage along its dorsal aspect.

Bilateral hind limb hypoplasia in a foal.

Hypoplasia affecting both hind limbs was observed in a neonatal foal. Scintigraphy aided in establishing diagnosis and prognosis. Radiography revealed an abnormally shaped middle phalanx and lack of the distal phalanx and navicular bone in the right hind limb, with an abnormally shaped distal phalanx and navicular bone in the left hind limb. Scintigraphic findings were closely correlated with the radiographic findings. Radiographic and scintigraphic findings were confirmed at postmortem examination.

Right hepatic lobe atrophy in horses: 17 cases (1983-1993).

The case records of 17 horses with atrophy of the right hepatic lobe were reviewed. Fifteen horses had signs of colic. Two horses had clinical problems that were unassociated with gastrointestinal tract disease. Ages ranged from 5 to 30 years (mean, 12.6 years) and there was no breed or sex predisposition. In clinically normal horses, the right hepatic lobe constitutes half of the total liver weight. The right hepatic lobe in the 17 horses in this study ranged from 11.0 to 38.3% of the total liver weight (mean, 27.8%). Findings on histologic examination of hepatic tissue from horses in the study were variable. Most had loss of hepatocytes, with condensation of hepatic stroma and thick wrinkled hepatic capsules. Additional findings in the horses included torsion of the large colon (15), ileus without gastric rupture (3), typhlocolitis (2), colon infarction secondary to mesenteric strangulation (1), colon infarction secondary to sepsis (1), strangulation of the small intestine from pendulous lipoma (1), and nephrosplenic entrapment (1). No morphologic evidence of angiopathic disease involving the arterial or venous blood supply to the right hepatic lobe was found. Additionally, there was no evidence of biliary tract disease in this portion of the liver. Right hepatic lobe atrophy is believed to result from long-term, insidious, compression of this portion of the liver from abnormal distention of the right dorsal colon and base of the cecum. The practice of feeding horses high-concentrate, low-fiber diets may contribute to atony of the right dorsal colon, with resultant distention that compresses the right hepatic lobe against the rigid, visceral surface of the diaphragm.

Adult-onset lysosomal storage disease in a Schipperke dog: clinical, morphological and biochemical studies.

An adult-onset lysosomal storage disorder was diagnosed in a 5-year-old Schipperke dog with progressive cerebellar and central vestibular signs. It was characterized by cerebellar atrophy with extensive loss of Purkinje and granular cells, and hydrocephalus. Enlarged and vacuolated neurons were observed in spinal cord and brain; pancreatic centrolobular and islet cells were also vacuolated. Ultrastructurally, enlarged secondary lysosomes laden with lamellated membrane structures were present in neurons and empty enlarged vacuoles were found in pancreatic centroacinar, ductal, and islet cells. On frozen sections neurons stained with Ricinus communis agglutinin-I and wheat germ agglutinin. On paraffin sections neurons stained with luxol fast blue, periodic acid-Schiff, Concanavalia ensiformis agglutinin, and were autofluorescent. These findings indicate an accumulation of glycolipids containing terminal beta-galactosyl and alpha-sialyl residues, and N-linked oligosaccharides. Tissue activity of lysosomal beta-galactosidase was 50% of normal and the activity of beta-hexosaminidase was elevated. Brain lipid-bound sialic acid was twice normal, with a small increase of GM1-ganglioside, but there was a significant elevation of GM2 (GD2) and GM3 (GD3). In addition, significant elevations of sialylated and non-sialylated oligosaccharides were noted. These clinical, biochemical and pathological findings are similar to those observed in human patients with adult-onset galactosialidosis.

Diagnosis of avian tuberculosis in a horse by use of liver biopsy.

A 15-month-old Appaloosa colt had pyrexia, weight loss, diarrhea, and dependent edema. Abnormal laboratory findings included anemia, hypoalbuminemia, and hyperglobulinemia. Activities of liver-specific enzymes in this colt were high. Analysis of a liver biopsy specimen resulted in a presumptive diagnosis of tuberculosis. We recommend that liver biopsy be used as a diagnostic procedure if the differential diagnosis in a horse includes avian tuberculosis or granulomatous enteritis, especially if serum activities of liver-specific enzymes are high.

Use of hepatobiliary scintigraphy to diagnose bile duct atresia in a lamb.

A neonatal lamb was admitted with icterus, hypoglycemia, increased liver enzyme activities, and delayed sulfobromophthalein clearance. Biliary and pancreatic duct atresia were documented in this lamb at necropsy. Hepatobiliary scintigraphy was useful in reaching an antemortem diagnosis of bile duct obstruction. Hepatobiliary scintigraphy, using 1.5 mCi of 99m technetium-labeled acid, was performed on the affected lamb and on an age-matched control lamb. Using a large field-of-view camera equipped with a low-energy parallel-hole collimator, right ventral oblique images of the thorax and abdomen were obtained. Images were simultaneously recorded on microdot film by use of a dedicated nuclear medicine computer. In the control lamb, there was rapid clearance of radioactivity from the blood pool, coincident with obvious accumulation of radioactivity in the liver and followed by sequential accumulation in the intrahepatic biliary system, gallbladder, common bile duct, and small intestine. Results of the study in the affected lamb were characterized by prolonged blood-pool radioactivity without appreciable hepatic uptake and by excessive renal and urinary bladder activity in the later phases of the study. Hepatobiliary scintigraphy was a safe and non-invasive procedure that provided quantitative information about the degree of bile duct obstruction in the affected lamb.

Experimental evaluation of absorbable copolymer staples for hysterectomy.

Absorbable copolymer staples of three different variants were tested for retention of tensile strength after implantation into the peritoneal cavity of rats. One type maintained tensile strength for two weeks, but then lost it rapidly over the next week. The same three staple compounds were further compared after use for vaginal vault closure during ovariohysterectomy in adult sheep. In all ewes the absorbable staples were effective in providing a stable vaginal cuff closure. The postoperative tissue reaction was minimal. The goal of developing an absorbable staple that would degrade rapidly without compromising wound stability was achieved.

Use of 111In-labeled autologous leukocytes to image an abdominal abscess in a horse.

Indium 111-labeled autologous leukocytes were used to image an abdominal abscess in a horse with a palpable abdominal mass and history of Streptococcus equi infection. A focal area of radioactivity was identified in the location corresponding to the abscess. Imaging of this focal uptake was optimal 48 hours after injection. Similar scans obtained in 2 clinically normal horses revealed no evidence of focal radioactivity in this region. The cell labeling procedure gave acceptable labeling efficiency (87.5%) but an excessive number of damaged WBC, resulting in persistent lung radioactivity on all images. No adverse effects were noted. Radiation measured in the horse and its excreta were well within acceptable limits.

Increased risk for lymphoma and glomerulonephritis in a closed population of cats exposed to feline leukemia virus.

Feline leukemia virus (FeLV)-associated diseases were observed in a household in eastern Connecticut having 134 cats over a period of five and a half years. FeLV-positive cats had a much higher mortality rate (34.6 deaths per 1000 cat-months of follow-up) than did FeLV-negative cats (8.9 deaths per 1000 cat-months of follow-up). The leading cause of death was glomerulonephritis followed by lymphoma. The relative risk for virus-positive cats as compared to virus-negative cats for the two diseases was 9.9 and 9.6, respectively. The major risk factors for the development of lymphoma were virus positivity and low antibody titer to the feline oncornavirus-associated cell membrane antigen (FOCMA). No significant differences in cancer incidence were seen between the two major breeds (Abyssinian and Burmese) in the household. An older age at arrival in the house decreased death rates for all causes in the household, but it did not significantly affect death rates from lymphoma, although there was a positive trend.

Lymphoproliferative diseases of fowl: characterization of transplantable G-B1 Marek's disease tumor cells in culture.

A transplantable Marek's disease tumor, derived and maintained through in vivo passage in syngeneic G-B1 chickens, was established in cell culture and characterized. The cells (GBT cells) grew in suspension and appeared morphologically similar to other Marek's lymphoblastoid lines except for prominent nucleoli in GBT cells. The number of chromosomes increased during in vitro cultivation from near triploid to subtetraploid. Chromosome no. 3 was abnormally short. The GBT cells retained surface B1 histocompatibility antigen of the original tumor as well as Marek's disease tumor-specific surface antigen (MATSA); however, infectious Marek's disease virus was not detected by immunofluorescence, electron microscopy, inoculation into susceptible birds, or assay on susceptible cells in culture. Inoculation of as few as 100 cultured cells into syngeneic G-B1 chickens results in tumor formation at the inoculation site, with eventual death of the recipients.

Duplication of colon in a Labrador Retriever with abnormal spinal column.

A 9-week-old male Labrador Retriever had duplication of the entire colon and malformation of the bodies of vertebrae T4 and T5. Simultaneous occurrence of alimentary duplication and spinal abnormalities have been reported in man, and several theories have been proposed to explain these embryonic defects.

Experimentally transmitted marble spleen disease in pen-raised wild turkeys.

Pen-raised North American wild turkeys (Meleagris gallopavo L.) were experimentally infected with marble spleen disease (MSD) to determine their susceptibility to this disease. Gross and microscopic lesions were consistent with experimental MSD in pheasants and domestic turkeys: an enlarged mottled spleen, intranuclear inclusion bodies, and absence of pulmonary edema and hemorrhage. Detectable levels of viral antigen were not demonstrable in sera of turkeys using the agar gell precipitin test.