Primary intimal aortic angiosarcoma in a dog.

A primary intimal aortic angiosarcoma was diagnosed in a 4-year-old, spayed female German Shepherd that presented for complications of thromboembolic disease because of infarcts in multiple organs. On gross examination, aneurysmal dilatation of the aorta was associated with a friable, necrotic mass attached to the endothelial surface, which partially occluded the aortic lumen. On histologic examination, plump neoplastic spindle cells formed a plaque-like mass arising from the intima that merged with a large accumulation of fibrin and necrotic debris, and projected into the lumen. Neoplastic cells invaded periaortic vessels and were seen in some infarct-associated thromboemboli. Tumor cells expressed vimentin and CD31, with infrequent, patchy staining with factor VIII-related antigen; tumor cells were negative for cytokeratin and smooth-muscle actin. Aortic angiosarcoma is a rare malignancy in humans. This is the first description of a primary intimal aortic angiosarcoma in a dog, with immunohistochemical evidence of endothelial origin.

Cytologic identification of Toxoplasma gondii in bronchoalveolar lavage fluid of experimentally infected cats.

OBJECTIVE: To determine whether it was possible to retrieve organisms, by means of bronchoalveolar lavage (BAL), from cats inoculated with Toxoplasma gondii. DESIGN: Experimental study. ANIMALS: 27 cats. Sixteen of the 27 were experimentally infected with feline immunodeficiency virus. PROCEDURE: All cats were inoculated with T gondii tachyzoites. Cats were grouped on the basis of feline immunodeficiency virus status and route (IV or intra-arterial) and number of tachyzoites administered. Bronchoalveolar lavage was performed by means of a standard technique. Lavage fluid was evaluated cytologically for tachyzoites. RESULTS: Clinical signs of toxoplasmosis varied widely among individual cats, but were generally most pronounced in group-1 and -2 cats (n = 5 each) and less pronounced in group-3 (n = 5) cats. Group-4 and -5 cats (n = 6 each) did not have clinical signs of toxoplasmosis. In 14 of the 15 cats in groups 1, 2, and 3, tachyzoites were detected in BAL fluid collected 7 days after inoculation. Tachyzoites were detected 14 days after inoculation in the single cat without tachyzoites 7 days after inoculation. A necropsy was performed on 9 of these cats, and tachyzoites were identified histologically in 4 of the 9. Tachyzoites were not detected in BAL fluid collected 3 days (n = 6) or 7 days (n = 6) after inoculation from the 12 cats in groups 4 and 5. Tachyzoites were not identified histologically in any of these 12 cats. CLINICAL IMPLICATIONS: BAL may be useful in the diagnosis of toxoplasmosis, particularly in cats with signs of pulmonary involvement.

Effect of FIV infection on lung inflammatory cell populations recovered by bronchoalveolar lavage.

Human immunodeficiency virus (HIV) and ovine progressive pneumonia virus have been associated with lymphocytic pneumonitis. Pulmonary cell populations in cats infected with feline immunodeficiency virus (FIV) were evaluated by bronchoalveolar lavage (BAL) to identify changes associated with lentivirus infection in this species. Bronchoalveolar lavage was performed through an endotracheal tube using 15 ml kg-1 body weight of sterile 0.9% sodium chloride solution. Results of BAL fluid cytologic analysis from 19 cats experimentally infected with FIV for at least 8 months were compared with results from 34 uninfected cats. Infected cats had significantly higher total cell counts and relative neutrophil counts (P < 0.01). Lymphocytosis did not occur. Bronchoalveolar lavage fluid was collected from nine additional cats prior to, and 2, 6, and 17-18 weeks following infection with FIV. Neither neutrophilia nor lymphocytosis was associated with FIV infection in these cats.

Myocarditis in mice and guinea pigs experimentally infected with a canine-origin Borrelia isolate from Florida.

OBJECTIVE: To characterize the pathogenic potential of a unique Borrelia isolate obtained from a dog from Florida (FCB isolate). DESIGN: Prospective experimental infection. ANIMALS: 32 preweanling Swiss Webster mice and 12 adult male Hartley guinea pigs were injected intraperitoneally with 10(5) spirochetes. PROCEDURE: Mice were used as controls and blood recipients, and at 3- to 4-day intervals, 1 control mouse and 2 infected mice were necropsied, tissues were cultured, and a recipient mouse was inoculated with blood. Guinea pigs were randomized to 4 groups and inoculated intradermally with 10(0), 10(2), 10(3), or 10(4) spirochetes. For 48 days, clinical, hematologic, serologic, and microbiologic tests were performed on them, after which they were necropsied. RESULTS: In mice, spirochetemia was detectable between postinoculation days (PID) 3 and 13, and seroreactivity to homologous antigen was detectable during PID 10 through 31. Compared with control mice, infected mouse spleens were 2 to 3 times larger. Histologic lesions included lymphoid hyperplasia, neutrophilic panniculitis, epicarditis, and myocarditis, with intralesional spirochetes detected from PID 3 through 6. During PID 10 through 31, nonsuppurative epicarditis developed. Signs of illness and hematologic abnormalities were not observed in guinea pigs, despite isolating spirochetes from blood during PID 7 to 27. When necropsied on PID 48, histologic lesions included lymphoid hyperplasia and lymphocytic plasmacytic epicarditis. CONCLUSIONS: The FCB isolate causes spirochetemia, lymphoid hyperplasia, dermatitis, and myocardial injury in Swiss Webster mice and can be transmitted by blood inoculation. In Hartley guinea pigs, the isolate causes spirochetemia, lymphoid hyperplasia, and epicarditis. Documentation of disease in mice, guinea pigs, and, presumably, dogs raises the level of concern that the FCB isolate might be pathogenic for man and other animal species.

Osteochondrosis of the articular-epiphyseal cartilage complex in young horses: evidence for a defect in cartilage canal blood supply.

The objectives of this study were to determine in horses 1) the ages at which viable cartilage canal vessels are present in the articular-epiphyseal cartilage complex of three predilection sites and one nonpredilection site of osteochondrosis (OC), 2) the prevalence of lesions of OC in these sites, and 3) whether there was an association of lesions of OC with necrotic cartilage canal blood vessels. The medial femoral condyle, lateral femoral trochlear ridge, and distal ends of the tibia and proximal phalanx were examined grossly, microradiographically, and histologically in 35 horses 18 months old or younger. Cartilage canals containing patent blood vessels were present in all sites examined in foals less than 3 weeks old and were absent from all sites by 7 months of age. The overall prevalence of lesions of OC at one or more of the sites examined was 12/35 (34%). Prevalence increased to 11/22 (50%) in horses 2 months old and older. These lesions occurred primarily in the medial condyle of the femur (n = 5) and the intermediate ridge of the distal tibia (n = 5). All lesions seen in horses between 3 weeks and 5 months of age were associated with necrotic cartilage canal blood vessels. In horses 7 months of age and older, lesions of OC were considered chronic because of extensive involvement of the subchondral bone and bone marrow. These results suggest that OC lesions develop prior to 7 months of age and that ischemic necrosis of cartilage secondary to a defect in vascular supply is an important factor in the pathogenesis of this disease in horses.

Diagnostic and therapeutic considerations in a hypercalcemic dog with multiple endocrine neoplasia.

Hypercalcemia was found in a dog examined for episodic weakness and disorientation. A right adrenal mass identified on abdominal ultrasonographic examination was diagnosed as a pheochromocytoma based on increased 1231-metaiodobenzylguanidine uptake and characteristic histopathological features. Serum intact parathyroid hormone (iPTH), total serum calcium, and ionized serum calcium were increased prior to surgery. Although both total and ionized serum calcium concentrations decreased to within normal reference ranges following surgery through postoperative day 17, subsequent high concentrations with increased serum iPTH concentrations confirmed concurrent primary hyperparathyroidism. A right parathyroid tumor was suspected based on a technetium-99m-sestamibi (99mTc-sestamibi) scan.

Cytologic characterization of bronchoalveolar lavage fluid collected through an endotracheal tube in cats.

Bronchoalveolar lavage was performed through an endotracheal tube in 34 specific-pathogen-free cats to determine expected values for bronchoalveolar lavage fluid cytologic analysis, using this method of collection. Saline solution for lavage was instilled in 3 separate aliquots at a volume of 5 ml/kg of body weight each. Analysis of sequential aliquots was performed to investigate the differences in cell counts among the 3 fractions. The effect of combining aliquots, including or omitting the first fraction, was evaluated to determine whether all aliquots could be combined for analysis without substantially affecting results. The total number of nucleated cells retrieved from each cat ranged from 0.9 to 31.1 x 10(6). Most of these cells were macrophages (78 +/- 15%, mean +/- SD) and eosinophils (16 +/- 14%). The first aliquot had the greatest number of epithelial cells, and the lowest total nucleated cell count and relative and absolute eosinophil counts. Differences among aliquots also were identified for relative and absolute macrophage counts, relative and absolute neutrophil counts, and absolute lymphocyte count. Statistically significant differences were found for many of the cell counts when values from the combination of the second and third aliquots were compared with values from the combination of all 3 aliquots. Magnitude of the differences was small, and these differences were not believed to be of practical consequence.

Natural infections with Borrelia spirochetes in two dogs from Florida.

Spirochetemia is a rarely reported observation in dogs. We describe the clinical, hematologic, and immunodiagnostic features of two spirochetemic dogs from northern Florida and the subsequent isolation and preliminary characterization of a Borrelia species from one dog in which culture of a sample for spirochetes was attempted. Results of polyacrylamide gel electrophoresis, monoclonal antibody testing, and PCR analysis indicate that the Florida isolate is not Borrelia burgdorferi, the only other member of the genus that has been isolated in Florida. Our findings also indicate that a member of the genus Borrelia potentially causes disease in dogs in Florida and that serologic cross-reactivity of the Florida canine Borrelia isolate with B. burgdorferi probably contributes to the inaccurate diagnosis of canine Lyme disease in the region.

Pituitary and thyroid gland lesions induced by 2-mercaptobenzimidazole (2-MBI) inhalation in male Fischer-344 rats.

2-Mercaptobenzimidazole (2-MBI) is a member of the thioureylene compound family known for their potent antithyroid activity. Male Fischer-344 rats were exposed to 0.0, 3.13, 12.5, and 50.0 mg/m3 of 2-MBI via inhalation for 13 wk. Follicular cell hyperplasia occurred in the thyroid glands of rats from the 3 2-MBI treatment groups. Thyrotrophs in the pituitary glands from rats in these 3 groups were hyperplastic, and they had varying numbers of hypertrophic cells with either eosinophilic stippled cytoplasm or with eosinophilic globules within 1 or more large vacuoles that displaced the nucleus. These cells were compared by immunohistochemistry and ultrastructural examination to "thyroidectomy cells" within the anterior pituitary glands of thyroparathyroidectomized rats and were determined to be identical to them. Immunohistochemical staining for the beta-chain of thyroid-stimulating hormone confirmed that the hyperplastic and hypertrophic cells were thyrotrophs. Ultrastructurally, hypertrophic cells in 2-MBI-treated rats and thyroidectomy cells in thyroparathyroidectomized rats had expanded cytoplasm containing either increased profiles of rough endoplasmic reticulum (RER) or one or more widely dilated cisternae of RER, which displaced other cellular organelles. 2-MBI appears to act comparably to other thioureylene compounds that have been shown to produce low serum concentrations of triiodothyronine and thyroxine, which results in thyrotroph hypertrophy and hyperplasia, resultant thyroid hyperplasia, and subsequent goiter.

Granulated round cell tumor of cats.

Morphologic and biologic features of five feline granulated round cell tumours were compared with those previously reported to be of globule leukocyte and large granular lymphocyte origin. The five cats ranged from 6 to 9 years of age and presented with nonspecific gastrointestinal signs. Four of the five cats were tested for feline leukemia virus and were negative by enzyme-linked immunosorbent assay. The neoplastic process involved the abdominal cavity in all cases, with a predilection for the distal small intestine and mesentery. The liver and peripheral and thoracic lymphoid tissues were also sporadically affected. Neoplastic round cells contained 0.5-1.5-microns eosinophilic cytoplasmic granules that were difficult to discern on causal observation with hematoxylin and eosin stain but were deep blue and easily visualized when stained with phosphotungstic acid-hematoxylin. In two cases, epithelium in the affected ileum and liver contained unusually large numbers of apparently normal globule leukocytes. Ultrastructurally, the tumor granules tended to cluster at one nuclear pole and were spindle to round in shape with variably dense contents. Some granules contained a dense "cap" at one end or internal crystalloid bars that distorted the granule membrane. The tumors reported herein are similar to all three of the previously reported feline granulated round cell tumors and probably have a common cellular origin.

Endemic visceral leishmaniasis in a dog from Texas.

Visceral leishmaniasis was diagnosed by cytology and positive indirect immunofluorescent antibody titers to Leishmania donovani in a 7-month-old female Basenji dog from Texas. Clinical and laboratory findings included weight loss, hematochezia, hyperglobulinemia, hypoalbuminemia, anemia, and neutrophilic leukocytosis. Evidence of response to treatment with diminazene aceturate and ketoconazole included improvement in the abnormal clinical, hematologic, and biochemical findings, decreased serum globulin concentration and antibody titer to Leishmania donovani, and absence of organisms in examined tissues. Several foci of endemic leishmaniasis have been reported in the United States. Because of its zoonotic potential and the lack of approved treatments for dogs with leishmaniasis in the United States, the development of effective treatment strategies is needed.

Detection of intravaginal spermatozoa after natural mating in the bitch.

Mismating is one of the most frequently presented reproductive problems presented to veterinarians. Confirming whether or not a mismating has occurred is necessary to determine if therapy will be instituted. Detection of spermatozoa in the vagina is irrefutable evidence of copulation; however, absence of sperm in a vaginal cytology cannot rule out coitus. In order to improve detection of spermatozoa post-coitus, a prospective study was initiated utilizing natural breedings of purebred beagles.

Short-chain fatty acids induce reversible injury of porcine colon.

Carbohydrate malabsorption frequently results in an increased net production of organic acids by colonic microorganisms and an acidification of colonic contents. Colonic structure and function during and following mucosal exposure to acetate at various H ion concentrations was examined under both in vivo and in vitro conditions. An acetic acid dose and time-dependent injury of the surface epithelium sequentially resulted in (1) degeneration and extrusion of enterocytes and increased ion permeability (pH 5.0); (2) formation of subepithelial blisters and increased mucosal permeability to mannitol (pH 4.0), and (3) sloughing of surface epithelium and the abolition of active NaCl absorption (pH 3.0). Both acetate and lactate at pH 4.0 produced significantly greater injury than similarly acidified NaCl. Crypt cell structure and Cl secretory function were preserved, however, and migration of viable cells from adjacent crypts rapidly covered the denuded surface within 30-60 min of recovery. Normal structure and function were nearly restored in 2 hr. These results suggest that colonic mucosal injury is possible under conditions that may be present during carbohydrate malabsorption syndromes. They also provide evidence that the process of surface reepithelialization may be of central importance in the defense and repair of the colonic mucosa during such acid-induced injury.

Ischemic necrosis of cartilage in spontaneous and experimental lesions of osteochondrosis.

This study was designed to examine the association of spontaneous lesions of osteochondrosis with vascular supply to epiphyseal cartilage, and to determine whether similar lesions could be experimentally reproduced by selective interruption of cartilage canal blood supply. The vascular supply to the articular-epiphyseal cartilage complex of the distal end of the femur was studied in 27 microfil- or barium-injected and cleared specimens and 24 serially sectioned microangiographic specimens from 27 clinically normal female swine (3.6 to 71.0 kg). Blood vessels supplying the articular-epiphyseal cartilage complex were consistently restricted to the epiphyseal region and the number of vessels decreased as the pigs increased in weight (p less than 0.001). Spontaneous lesions of osteochondrosis (i.e., cartilage necrosis) were initially seen in the first areas of epiphyseal cartilage to become avascular and were associated with necrotic blood vessels. The number and size of foci of necrotic cartilage increased as the pigs increased in weight (p less than 0.001). Blood supply to epiphyseal cartilage from cartilage canal vessels was surgically interrupted in a highly vascular area of the medial femoral condyle in eight additional 23-kg female swine. This procedure resulted in necrosis of blood vessels within cartilage canals followed by necrosis of surrounding cartilage, lesions that appeared to be identical to early spontaneous lesions of osteochondrosis. These results suggest that the viability of epiphyseal cartilage in the articular-epiphyseal cartilage complex is highly dependent on an adequate blood supply from cartilage canal vessels, and strongly implicates a defect in blood supply in the pathogenesis of osteochondrosis.

Bone fragility in a kitten: an osteogenesis imperfecta-like syndrome.

A 12-year-old kitten was found to have bone fragility. Previously described causes of bone fragility in domestic cats were excluded on the basis of serum biochemical profile and radiographic histologic examinations. The findings in this kitten correlated most closely with osteogenesis imperfecta, a syndrome documented in human beings and cattle.

Villous atrophy, crypt hyperplasia, cellular infiltration, and impaired glucose-Na absorption in enteric cryptosporidiosis of pigs.

Intestinal morphology and fluid and electrolyte transport were examined in a neonatal porcine model of cryptosporidiosis. Sections of jejunum, ileum, and colon were obtained for morphometric analysis on days 3, 6, 9, and 12 postinfection, and in vivo perfusion studies of jejunum and ileum were conducted on days 3 and 4 postinfection. The most severe morphologic lesion was seen in the ileum on day 3, and consisted of villous atrophy, crypt hyperplasia, and cellular infiltration. Villous surface area was reduced from 2.1 +/- 0.4 x 10(5) microns2 in control ileum to 0.8 +/- 0.1 x 10(5) microns2 in infected ileum, a result associated with enterocytes that were fewer in number and reduced in cross-sectional area. Conversely, the number of inflammatory cells in the lamina propria of the villus increased from 456 +/- 116 in control to 1014 +/- 187 in infected villus without a significant change in the volume of the lamina propria. At the height of infection, there was an approximate 1:2 ratio of both organisms and inflammatory cells to villous enterocytes. In contrast, organisms were not observed in the crypts, and the concentration of inflammatory cells in crypt lamina propria was unaltered. Disappearance of organisms and polymorphonuclear cells from the ileum was associated with restoration of normal structure and was complete by day 12. Although organisms were seen in the colon, the general architecture was not severely affected. On days 3 and 4 postinfection, there was a complete impairment of the glucose-stimulated Na and water absorption in both jejunum and ileum of infected pigs; however, absorption of electrolytes and water from a basic Ringer's solution, in the absence of glucose, was not significantly affected. These results are consistent with a malabsorptive diarrheal disease associated with the morphological damage and are very similar to those seen in enteric viral disease in pigs, except that the upper intestine is more severely affected in the latter.

Degeneration of cartilage canal vessels associated with lesions of osteochondrosis in swine.

Articular-epiphyseal cartilage complexes from the distal femur and humerus of five 3-month-old pigs were collected and preserved using either a conventional or a ruthenium hexammine trichloride (RHT)-supplemented fixation technique. Lesions were similar regardless of the fixation technique. Areas of necrosis were in epiphyseal but not articular cartilage from both sites of all pigs. Cartilage canals were confined to epiphyseal cartilage and contained vessels which had endothelial cells in varying stages of degeneration and necrosis. Areas of necrotic cartilage often were adjacent to or surrounded degenerate cartilage canals. Lipid emboli (up to 40.0 micron in diameter) were infrequently located in vessels within cartilage canals. Associated with the lipid emboli were leukocytes, erythrocytes, necrotic cell remnants, and flocculent material. Restriction of necrosis to epiphyseal cartilage and the association of these necrotic areas with degenerating vessels in cartilage canals strongly implicate a defect in cartilage canal blood supply in the pathogenesis of osteochondrosis. The RHT fixation technique resulted in excellent cellular detail at the light microscopic level, but ultrastructurally there was marked vacuolation of chondrocytes and matrix. The conventional technique caused shrinkage of all chondrocytes, resulting in a wide halo of pericellular matrix surrounding each cell.