Comparison of radiography and computed tomography to evaluate fractures of the canine tarsus

Detection and accurate classification of traumatic tarsal fractures are important for identifying cases requiring surgical intervention. The aim of this prospective, experimental, methods comparison study was to directly compare the accuracy, sensitivity, and specificity of tarsal computed tomography (CT), ten‐view and two‐view digital radiographs for detecting traumatic fractures of the canine tarsus. The working hypothesis was that tarsal fractures would be detected with higher accuracy, sensitivity, and specificity using CT imaging compared to radiography, and a ten‐view would be superior to a two‐view radiographic study. Ten cadaver hind limbs of medium to large dogs received a CT scan and ten‐view radiographic study before and after induction of fractures with a hydraulic press. All bones included in the radiographic images were assessed for fractures by two observers and gross dissection was used as the gold standard. The two‐view radiographic study (dorsoplantar, lateromedial) was created from the ten‐view study and reviewed 2 years later. All limbs sustained fractures, the most common locations were the talus and calcaneus (n = 7). The sensitivity of CT was greater than ten‐view radiographic study (77% vs. 57%), while the specificity was similar (97% vs. 98%). The sensitivity and specificity of the ten‐view and two‐view radiograph studies were similar (57% vs. 55%; both 98%). Computed tomography images were reassessed postdissection to determine if failure to identify fractures resulted from observer error. Overall, CT was better than radiography for detecting fractures of the canine tarsus, however there was little improvement with ten‐view compared to two‐view radiographic studies.     

Lomustine for treatment of mast cell tumors in cats: 38 cases (1999-2005)

OBJECTIVE: To determine clinical activity and toxic effects of lomustine when used to treat cats with mast cell tumors (MCTs). DESIGN: Retrospective case series. ANIMALS: 38 cats with measurable, histologically or cytologically confirmed MCTs treated with lomustine at a dosage > or = 50 mg/m(2). PROCEDURES: Medical records were reviewed to determine response to treatment and evidence of drug toxicoses. The Kaplan-Meier method was used to estimate remission duration. RESULTS: 26 cats had cutaneous MCTs, 7 had MCTs of the mesenteric lymph nodes, 2 had gastrointestinal tract MCTs, 2 had hepatic MCTs, and 1 had MCTs involving multiple organs. Targeted lomustine dosage was 50 mg/m(2) in 22 cats and 60 mg/m(2) in 16 cats. Median administered dosage of lomustine was 56 mg/m(2) (range, 48 to 65 mg/m(2)), and median number of doses administered was 2 (range, 1 to 12). Seven cats had a complete response and 12 had a partial response, for an overall response rate of 50%. Median response duration was 168 days (range, 25 to 727 days). The most common toxicoses were neutropenia and thrombocytopenia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that lomustine had activity against MCTs in cats and was well tolerated. Further, findings suggested that treatment with lomustine should be considered for cats with MCTs for which local treatment is not an option.     

Cytomorphologic differentiation of benign and malignant mammary tumors in fine needle aspirate specimens from irradiated female Sprague-Dawley rats.

BACKGROUND: Fine needle aspiration (FNA) offers a rapid and minimally invasive means to distinguish malignant from benign neoplasms. However, few studies have been published regarding the cytopathology of mammary tumors in rats despite widespread use of the rat model for breast cancer formation and inhibition. OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of FNA cytology and to develop distinguishing cytologic criteria for the diagnosis of radiation-induced benign and malignant mammary tumors in rats. METHODS: In a study of radiation-induced mammary carcinogenesis, 100 Sprague-Dawley rats with cutaneous masses were randomly chosen for FNA. The aspirates were smeared, fixed, and stained with a modified Papanicolaou procedure for diagnostic evaluation. Cytologic and histologic diagnoses (benign vs malignant) were compared, and diagnostic accuracy was calculated using the histologic diagnosis as the criterion standard. FNA smears were scored semiquantitatively on a scale of 1-4 for cellularity, atypia, nuclear size, chromatin pattern, nuclear membrane thickness, nucleoli, and mitoses. The background was evaluated for necrosis, hemorrhage, inflammation, and mucosecretory material. Cytomorphologic features were compared statistically between benign and malignant tumors, based on the histologic diagnosis. RESULTS: The sensitivity of FNA was 92.3% and specificity was 89.4% for the detection of malignancy. However, 14% of specimens, all fibroadenomas by histology, had insufficient cells for cytologic evaluation, for an overall accuracy rate of 78.0%. Malignant tumors had significantly higher scores for all cytomorphologic features, and were significantly more likely to contain cell clusters and necrotic debris. CONCLUSIONS: FNA is an accurate method for differentiating benign and malignant rat mammary tumors.     

Bilateral hydronephrosis secondary to endometriosis managed by endoscopic ureteral stent placement in a captive Guinea baboon (Papio papio)

Spontaneous endometriosis is an estrogen-dependent, progressive and painful disease that affects a variety of nonhuman primates, including several species of baboons (Papio sp.). This case documents multimodal management of severe endometriosis in a captive female baboon within a zoological institution. An 18-yr-old, intact female Guinea baboon (Papio papio) was found to have an enlarged uterus. Fifteen months post ovariohysterctomy, scarring associated with endometrial tissue resulted in ureteral strictures, bilateral hydronephrosis, and azotemia. Cystoscopic placement of bilateral ureteral stents with fluoroscopy was performed and resulted in short-term clinical improvement. The animal's condition declined and euthanasia was elected 4 mo after ureteral stent placement. Severe endometriosis with secondary inflammation resulting in bilateral hydroureter and hydronephrosis, as well as concurrent cystitis, ureteritis, and pyelonephritis were confirmed at necropsy. Despite possible complications, ureteral stents can be considered a useful therapeutic option in patients with ureteral disease.     

Failure of nebulized irritant, acidic, or hypotonic solutions or external mechanical stimulation of the trachea to consistently induce coughing in healthy, awake dogs

A useful approach for evaluating antitussive drugs in humans is to determine the sensitivity of the cough reflex to a standard challenge. The purpose of this study was to determine if methods used to induce coughing in humans would be effective when used on awake, untrained, healthy dogs for future application in therapeutic trials involving dogs with spontaneous disease. Methods tested were: mechanically stimulating the trachea by digital compression as well as by vibration from an electric shaver, neck massager, and palm sander (11 dogs), and administering nebulized irritant (3000 μM capsaicin), acidic (1 M citric acid), and hypotonic (deionized water) solutions using face masks (4 dogs). The threshold for success was defined as induction of at least 2 moderate or strong coughs in at least 75% of the dogs. None of the methods tested was successful. Digital compression induced soft (n = 2) or moderate (n = 1) coughing in 3 of 11 dogs tested. Nebulization of citric acid induced 1 soft cough in 1 of 4 dogs. It was concluded that coughing cannot be successfully induced in awake, healthy dogs using methods that are successful in humans. Other strategies must be developed so that cough sensitivity can be objectively and non-invasively measured in dogs for clinical research purposes.     

Ultra‐frequent HRAS p.Q61R somatic mutation in canine acanthomatous ameloblastoma reveals pathogenic similarities with human ameloblastoma

Ameloblastoma is a locally aggressive odontogenic tumour that occurs in humans and dogs. Most ameloblastomas (AM) in humans harbour mutually‐exclusive driving mutations in BRAF, HRAS, KRAS, NRAS or FGFR2 that activate MAPK signalling, and in SMO that activates Hedgehog signalling. The remarkable clinical and histological similarities between canine acanthomatous ameloblastoma (CAA) and AM suggest they may harbour similar driving mutations. In this study, aimed at characterizing the mutational status of SMO, BRAF, HRAS, KRAS, NRAS and FGFR2 in CAA, we used RNA sequencing, Sanger sequencing and restriction fragment length polymorphism assays to demonstrate that 94% of CAA (n = 16) harbour a somatic HRAS p.Q61R mutation. The similarities in MAPK‐activating mutational profiles between CAA and AM implicate conserved molecular mechanisms of tumorigenesis, thus, qualifying the dog as a potentially useful model of disease. Given the relevance of RAS mutations in the pathogenesis of odontogenic tumours and other types of cancer, the results of this study are of comparative, translational, and veterinary value.     

Route of nutrient delivery

Nutritional intervention early in the course of critical illness in humans and animals can have a significant impact on morbidity and mortality. Enteral delivery of nutrients is less technically demanding, more physiologic, and less expensive than parenteral nutrition. Furthermore, as complete bowel rest during critical illness can be associated with detrimental intestinal structural and functional changes ultimately resulting in bacterial translocation from the gut, direct delivery of nutrients to the gastrointestinal tract is preferred in patients with sufficient gastrointestinal function to allow digestion and absorption of nutrients. Once the decision to "feed the gut" has been established, there are several routes of enteral nutrient delivery available. A sound knowledge of gastrointestinal function, anticipated duration of enteral support, and co-moribund conditions will help the clinician tailor a plan of nutrient delivery that optimally meets each patient's needs. This article will review available routes of nutrient delivery to the gastrointestinal tract, and discuss indications and contraindications for each.