Bovine leukemia virus infection in a juvenile alpaca with multicentric lymphoma.

A 13-month-old alpaca (Vicugna pacos) was presented for mandibular masses and weight loss. Histopathology of biopsy tissue was consistent with lymphoma. The alpaca was euthanized and necropsy revealed lymphoma masses in multiple organs. Immunohistochemistry for T- and B-cell typing was inconclusive. Serology and in-situ polymerase chain reaction hybridization were positive for bovine leukemia virus.

Sensitivity of low-field T2 images for detecting the presence and severity of histopathologic meniscal lesions in dogs.

The sensitivity of low-field magnetic resonance (MR) T2 images for predicting the presence of meniscal lesions was determined in 12 dogs with naturally-occurring cranial cruciate ligament rupture and three control dogs, using histopathology as the reference standard. Previously published grading systems were used to grade the severity of meniscal lesions on MR images, gross inspection and histopathology. Focal areas of increased signal intensity were detected in 11/12 symptomatic dogs and 3/3 control dogs. Lesions mimicking meniscal tears (pseudotears) were identified at junctions between meniscal margins and adjacent connective tissue in control dogs and dogs with naturally occurring disease. Histopathologic lesions were present in all menisci of both symptomatic and control dogs, including the menisci from two affected dogs that appeared grossly normal but were removed and submitted based on MR imaging findings. Histopathologic lesions identified included hyaline cartilage metaplasia and changes in the amount of ground substance and cellularity. The sensitivity of MR imaging for detecting the presence of meniscal histopathologic lesions was 90% in symptomatic dogs and 91% in control dogs. However, agreement between severity scores for the different tests was poor. Low-field MR imaging is a sensitive test for predicting the presence but not severity of meniscal histopathologic lesions in dogs with naturally-occurring cranial cruciate ligament rupture. Findings also supported previous studies indicating that histopathologic lesions can be present in dogs with grossly normal menisci. An improved grading system for comparing MR images and histopathologic severity of meniscal lesions in dogs is needed.

Imaging diagnosis--Dorsal mediastinal T-cell lymphoma in an alpaca.

A 14-year-old male alpaca had refractory pleural effusion. The cause of the effusion was not apparent either radiographically or sonographically, or following a pleural fluid cytologic examination. Using computed tomographic (CT) examination, a dorsal paravertebral mass was identified and similar masses were found in the cranial mediastinum, retroperitoneal space, and adjacent to the hepatic entry of the portal vein. The histopathologic diagnosis was multicentric T-cell lymphoma. CT examination may prove to be a valuable imaging modality in the localization and staging of neoplasia in new world camelids.

Concurrent nasal adenocarcinoma and rhinosporidiosis in a cat.

A 10-year-old, neutered, male Domestic Shorthair cat was presented to the teaching hospital for labored breathing, anorexia, and weight loss of several months duration. External examination revealed distortion of the bridge of the nose and pink fleshy polyps protruding from each nostril. The cat was euthanized and submitted for postmortem examination. In addition to the external findings, the nasal cavity had extensive bone and cartilage loss and contained a tan firm mass in the caudal region of the nasal cavity near the cribriform plate. On histologic examination, the mass was a nasal adenocarcinoma, and the polyps were composed of hyperplastic nasal epithelium and submucosal stroma that contained sporangia consistent with Rhinosporidium seeberi.

Histophilus somni biofilm formation in cardiopulmonary tissue of the bovine host following respiratory challenge.

Biofilms form in a variety of host sites following infection with many bacterial species. However, the study of biofilms in a host is hindered due to the lack of protocols for the proper experimental investigation of biofilms in vivo. Histophilus somni is an agent of respiratory and systemic diseases in bovines, and readily forms biofilms in vitro. In the present study the capability of H. somni to form biofilms in cardiopulmonary tissue following experimental respiratory infection in the bovine host was examined by light microscopy, transmission electron microscopy, immunoelectron microscopy of ultrathin cryosections, scanning electron microscopy of freeze-fractured samples, and fluorescent in situ hybridization. Biofilms were evident and most prominent in the myocardium, and were associated with a large amount of amorphous extracellular material. Furthermore, Pasteurella multocida was often cultured with H. somni from heart and lung samples. Transposon mutagenesis of H. somni strain 2336 resulted in the generation of mutants that expressed more or less biofilm than the parent strain. Six mutants deficient in biofilm formation had an insertion in the gene encoding for a homolog of filamentous haemagglutinin (FHA), predicted to be involved in attachment. Thus, this investigation demonstrated that H. somni is capable of forming a biofilm in its natural host, that such a biofilm may be capable of harboring other bovine respiratory disease pathogens, and that the genes responsible for biofilm formation can be identified by transposon mutagenesis.

Effect of nephrotomy on renal function and morphology in normal cats.

OBJECTIVE: To assess effects over 12 weeks of bisection nephrotomy on renal function, size, and morphology in cats. STUDY DESIGN: Controlled, randomized, blinded experiment. SAMPLE POPULATION: Ten adult female cats. METHODS: Glomerular filtration rate (GFR), determined by quantitative renal scintigraphy using (99m)Technetium-diethylenetriamine-pentaacetic acid, urinalysis, urine culture, and ultrasonographic measurement of renal size were performed preoperatively. Left or right nephrotomy (5 cats/group) was performed. Total and individual kidney GFRs were determined at 2, 28, and 84 days, ultrasonographic measurements at 28 and 86 days, and ultrasound-guided biopsy at 86 days. RESULTS: No significant differences in mean GFR and kidney size of operated versus unoperated kidneys were observed. Individual GFR and renal size of all except 1 cat remained within normal limits. Two cats had evidence of transient ureteral obstruction in the immediate postoperative period. No significant, generalized histologic abnormalities were observed. CONCLUSIONS: Bisection nephrotomy in normal cats does not adversely affect renal function or morphology during the initial 12 weeks. CLINICAL RELEVANCE: Bisection nephrotomy can be safely performed in normal feline kidneys without causing a significant deleterious effect on renal function. Studies in cats with pre-existing renal insufficiency are needed to ensure adverse effects would not occur in clinical cases where this surgical procedure is warranted.

Lymphoma and Mycobacterium avium infection in a ferret (Mustela putorius furo).

A 6-year-old, neutered male ferret presented with weight loss. Radiography revealed an enlarged liver and other abdominal masses. The ferret was euthanized, and at necropsy, the stomach wall was thickened, mesenteric lymph nodes were enlarged, and the liver contained multifocal tan nodules. Histopathology confirmed lymphoma and granulomatous inflammation in all affected organs. Acid-fast bacilli were present in the lesions and were confirmed to be Mycobacterium avium by PCR.

Fibrocartilaginous embolic myelopathy in a calf.

A 5-month-old Angus heifer with a history of acute hindlimb paresis that quickly progressed to lateral recumbency was necropsied. Gross lesions included a 6-cm segment of gray to brown discoloration and softening of the right ventrolateral spinal cord between T2 and T3. Microscopically, there was liquefactive necrosis of ventrolateral white and gray matter, and multiple intravascular emboli partially or completely occluded many intralesional and adjacent spinal and meningeal arteries and veins. Emboli were alcian blue positive, consistent with fibrocartilage of the nucleus pulposus of the intervertebral disk. No gross abnormalities were detected in the vertebrae or intervertebral disks. Fibrocartilaginous embolic myelopathy appears to be very rare in cattle; however, it should be considered in cases of acute, nonprogressive spinal cord dysfunction.

Systemic candidiasis in a dog.

Candida albicans is a common cause of nosocomial infections in humans, but there are few reports of systemic candidiasis in dogs. This report describes an 11-year-old spayed female Scottish Terrier with systemic candidiasis. The diagnosis was made on the basis of results of microbiologic culture of specimens from urine and venous catheters and histologic examination of tissues obtained post mortem. Factors that predisposed the dog of this report to systemic candidiasis included diabetes mellitus, corticosteroid and broad-spectrum antimicrobial administration, venous and urinary catheterization, and administration of nutrition parenterally. The development of pyrexia and leukocytosis in dogs with risk factors that predispose to Candida spp infections warrants evaluation via microbial culture of specimens from urine and vascular catheters used in those dogs.

Synovial regeneration in the equine carpus after arthroscopic mechanical or carbon dioxide laser synovectomy.

OBJECTIVE: To compare synovial regeneration in the equine carpus after mechanical or CO(2) laser synovectomy. STUDY DESIGN: Arthroscopic partial synovectomy was performed in the radiocarpal and intercarpal joints. SAMPLE POPULATION: Twelve horses, 3 to 6 years of age, were randomly divided into 3 groups. METHODS: The antebrachiocarpal and intercarpal joints in each horse were randomly assigned a treatment such that each horse had one joint treated as a control (arthroscopic lavage), one in which a mechanical or CO(2) laser partial dorsal carpal synovectomy was performed, and one in which a combination of the mechanical and laser techniques was performed. The groups were euthanized for collection of specimens, respectively, at 1, 3, and 6 months postoperatively. The synovial membrane was evaluated grossly, histologically, and by transmission and scanning electron microscopes (TEM and SEM). RESULTS: The synovial villi failed to regenerate in all groups. At 1 month, the intimal cell layer was incomplete and the surface was still granulating. At 3 months, intimal regeneration was complete but more mature in the CO(2) laser synovectomy groups than in the mechanical synovectomy groups. Intimal regeneration was complete in all groups at 6 months. The subintima was replaced with fibrous tissue that separated the original subintimal vascular bed from the regenerated synovial surface. The CO(2) laser required preliminary training to operate effectively, and the air environment altered the intraoperative evaluation of the synovectomy site. CONCLUSIONS: Villous regeneration does not occur in horses after surgical synovectomy. All synovial membranes healed with a fibrous subintima and less populated intima. The CO(2) laser is capable of performing a more superficial synovectomy than that achieved with mechanical synovectomy using a motorized arthroscopic synovial resector. CLINICAL RELEVANCE: Mechanical or CO(2) laser synovectomy may be performed in the horse; however, additional evaluation is needed to determine the physiological significance of the lack of villus regeneration in this species. A combination of the resection techniques is not advised because of the increased risk of full-thickness capsular defects.

A comparison of the cytologic and histologic features of meningiomas in four dogs.

The cytologic and histologic features of 2 intracranial and 2 spinal (extramedullary cervical) canine meningiomas were compared. Cerebrospinal fluid analysis in 2 cases revealed mild, mixed cell pleocytosis, primarily composed of small lymphocytes and monocytoid cells, with a moderate increase in total protein concentration. Cytologic features suggestive of meningioma included cells with both epithelial and mesenchymal characteristics and a tendency towards cell clustering. Tumor location also was useful in making a diagnosis. The 4 meningiomas differed histologically from one another, and included angioblastic, psammomatous, meningotheliomatous, and microcystic anaplastic types, which conformed to a classification scheme for human meningiomas. The classification scheme could not be applied to cytologic specimens.