Geoffrey K. Saunders

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.

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.

Suspected Citrus Pulp Toxicosis in Dairy Cattle

Thirteen lactating dairy cows from a herd of 650 died over a 6-week period. Most animals were down in milk production at 1 milking and were found dead at the next milking. Two cows had elevated heart rate and enlarged mandibular lymph nodes. Two others had azotemia, elevated heart rate, hyperglycemia, and weight loss. Necropsy of 10 cows revealed hemorrhages on the intestinal serosa and epicardium, lymphadenopathy, interstitial nephritis, small intestinal hemorrhage, and interstitial pneumonia. Histopathology showed lymphocytic to lymphogranulomatous inflammation in the heart, spleen, kidney, lymph nodes, liver, lung, pancreas, and adrenal gland. Phlebitis was present in 2 livers. The lesions resembled those of hairy vetch toxicosis, but no vetch was being fed. Similar lesions have been reported with the feeding of citrus pulp. Citrus pulp was being fed to the lactating cows and had been added to the diet 6 weeks before the first death. The syndrome resolved with elimination of citrus pulp from the diet.

A histopathologic study of the effects of gossypol on the female rat

The purpose of this study was to examine the tissues of female rats treated with gossypol acetic acid for morphologic evidence of an underlying mechanism of infertility. The number of estrous cycles, and body and adrenal weights were also compared. The number of estrous cycles decreased in rats treated with 60 mg/kg gossypol acetic acid for 30 days. Body weights were also reduced in rats treated with 40 mg or 60 mg/kg per day for 30 days when compared to controls. However, no significant differences were found in any group when comparing adrenal weights, adrenal weight/body weight ratios or adrenal histology. The body weight loss was related, at least in part, to diarrhea and dehydration in eight of the treated animals. It is interesting that though the gossypol-treated rats had reduced numbers of estrous cycles, no histopathologic changes were found in their ovaries, uterus or vagina.

A Comparison of Hepatic Sonographic Features and Histopathologic Diagnosis in Canine Liver Disease: 138 Cases

BACKGROUND Ultrasound examination is commonly used in the diagnostic evaluation of liver disease in dogs. HYPOTHESIS/OBJECTIVES To determine if hepatic sonographic features were predictive of findings on liver histopathology. We hypothesized that there would be a relationship between sonographic features and the category of liver disease based on histologic assessment. ANIMALS One hundred and thirty-eight dogs in which the liver was evaluated by both abdominal ultrasound examination and histopathologic examination. Twenty-five dogs were included in each of the following categories based on histopathology: normal, degenerative, vascular, inflammatory, and neoplasia. Thirteen dogs had nodular regeneration. METHODS Retrospective study. Medical records of dogs from 2005 to 2010 were searched for cases in which the liver was evaluated by abdominal ultrasound examination as well as by histopathology. After independent evaluation of ultrasound images, the recorded sonographic features were analyzed to identify abnormalities associated with each histopathologic diagnosis or degree of fibrosis. RESULTS Sixty-four percent of sonographically unremarkable livers had histologic abnormalities. Both microhepatia and the identification of abnormal vasculature were significantly associated with a histopathologic diagnosis of vascular disease. Hepatic masses were significantly associated with a diagnosis of neoplasia. Dilated common bile duct and thickened gall bladder wall were significantly associated with hepatitis. There were no sonographic findings consistently present with hepatic fibrosis. CONCLUSION AND CLINICAL IMPORTANCE Although some ultrasonographic findings, including masses, microhepatia, anomalous veins, and biliary changes, are associated with specific histopathologic abnormalities, sonographic findings are inconsistently detected in many disorders. Overall, hepatic ultrasonographic abnormalities have substantial limitations in predicting the underlying disease.

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.

Canine Sterile Nodular Panniculitis: A Retrospective Study of 14 Cases

BACKGROUND Sterile nodular panniculitis (SNP) is an uncommon inflammatory condition of subcutaneous fat that can be idiopathic, but has also been associated with underlying conditions such as pancreatic disease or systemic lupus erythematosus (SLE). The pathogenesis and clinical course of the condition are not well understood. OBJECTIVES To retrospectively review cases of SNP associated with systemic signs, concurrent disease, or both and characterize the clinical, laboratory, imaging, and histopathologic findings, treatment, and response to treatment. ANIMALS Fourteen dogs with histologically confirmed SNP diagnosed between 1996 and 2008. METHODS Retrospective study. RESULTS Skin lesions were ulcerated or draining nodules in 9 dogs and nonulcerative subcutaneous nodules in 5. Most dogs had systemic signs, such as fever, inappetence, lethargy, and multiple lesions. Common clinicopathologic findings included neutrophilia with or without left shift, increased alkaline phosphatase activity, mild hypoglycemia, hypoalbuminemia, and proteinuria. Concurrent diseases included pancreatic disease, SLE, rheumatoid arthritis, polyarthritis, lymphoplasmacytic colitis, and hepatic disease. Dogs responded to immunosuppressive doses of corticosteroids when administered. Prognosis for recovery was related to the underlying disease process. CONCLUSIONS AND CLINICAL IMPORTANCE SNP is not a single disease. Rather, it is a cutaneous marker of systemic disease in many cases. After thorough evaluation for concurrent disease and infectious causes, immunosuppressive treatment is often effective.

Idiopathic eosinophilic masses of the gastrointestinal tract in dogs.

BACKGROUND Eosinophilic inflammation of the gastrointestinal tract of dogs occurs in numerous disorders, typically resulting in diffuse intestinal thickening. Rarely, eosinophilic masses have been reported. OBJECTIVE Describe a series of dogs with 1 or more idiopathic eosinophilic gastrointestinal masses (IEGM) to better characterize the clinical features, treatment, and prognosis. ANIMALS Seven dogs with 1 or more gastrointestinal masses composed primarily of eosinophilic infiltrates for which no underlying cause was found. METHODS Retrospective case series. RESULTS Rottweilers and purebred, large breed dogs predominated. Dogs were middle-aged and typically had chronic signs of upper or lower gastrointestinal disease. Decreased appetite, vomiting, and evidence of gastrointestinal hemorrhage were present in the majority of cases. An abdominal or rectal mass was frequently noted on physical examination. Common laboratory abnormalities included peripheral eosinophilia, mature neutrophilia, hypoproteinemia, and hypocholesterolemia. The masses were histologically composed of moderate to severe eosinophilic infiltrates, which were often transmural and accompanied by fibrosis. All dogs treated with surgery alone died of complications of their disease. Treatment with corticosteroids and ivermectin improved clinical signs, caused resolution of eosinophilic infiltrates, and prolonged survival in most dogs treated medically. CONCLUSIONS AND CLINICAL IMPORTANCE These findings suggest that the prognosis for dogs with IEGM may be good when recognized and managed appropriately. When surgery is performed, medical treatment should also be added.

Evaluation of horizontal and vertical tracheotomy healing after short-duration tracheostomy in dogs

PURPOSE The purpose of the study was to assess healing of horizontal and vertical tracheotomy after short-duration tracheostomy in dogs using clinical, radiographic, endoscopic, and histologic methods. MATERIALS AND METHODS Horizontal tracheotomy (n = 6) between the third and fourth tracheal rings or vertical tracheotomy (n = 6) across tracheal rings three through five was performed for airway management during laryngoplasty. Tracheostomy tubes were maintained for 6 hours with low-pressure cuff inflation time limited to the first 1.5 hours. Cervical radiographs and tracheoscopy were performed preoperatively and at postoperative weeks 2, 4, 8, and 12. Ten of the 12 dogs were killed 12 weeks after tracheostomy. RESULTS There was no significant difference in preoperative and postoperative tracheal diameter or change in endoscopic tracheal circumference at the tracheostomy site when dogs were compared based on type of tracheotomy. Three dogs with horizontal tracheotomies had evidence of scar (web) within the tracheal lumen 12 weeks after surgery. All vertical tracheotomies had a mild, ventral, triangular deformity. Histologic examination of vertical tracheotomy sites showed complete restoration of the pseudostratified columnar epithelium. Horizontal tracheotomies healed with a single layer of columnar epithelium. Intraluminal scar was composed primarily of loose connective tissue. CONCLUSION Based on the results of this study, vertical tracheotomy shows more consistent healing compared with horizontal tracheotomy after short-duration tracheostomy. No evidence was found to support the preferential recommendation of horizontal tracheotomy for short-duration tracheostomy airway management.

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.