Actinomycin D for Reinduction of Remission in Dogs With Resistant Lymphoma

Twenty-five dogs with malignant lymphoma refractory to chemotherapy were treated with actinomycin D at a median dose of 0.7 mg/m² (range, 0.5 to 0.9 mg/m²) every 3 weeks. The dogs treated had received between 2 and 8 chemotherapeutic agents (median 7), for a median of 266 days before being treated with actinomycin D. For 23 of the 25 dogs, previous chemotherapy included doxorubicin. No dog responded to actinomycin D chemotherapy.     

ULTRASONOGRAPHY OF ALIMENTARY LYMPHOSARCOMA IN THE CAT

Clinical, radiological and ultrasonographic findings from 22 cats with gastrointestinal lymphosarcoma were reviewed. The most common clinical findings were anorexia, weight loss, vomiting, lethargy, depression, fever, anemia and a palpable abdominal mass. Abdominal radiographs of 12 cats revealed a mass associated with the gastrointestinal tract and/or mesentery, and decreased serosal detail, suggestive of peritoneal effusion. The most common ultrasonographic finding was transmural gastric or intestinal thickening associated with loss of normal wall layering, reduced wall echogenicity and localized hypomotility. As is noted in people, other patterns such as transmural-segmental, transmural-nodular, transmural-bulky and mucosal infiltration were represented. In 3 cats, mesenteric lymph-adenopathy was responsible for most of the mass-effect. Fine-needle aspiration biopsy, automated microcore biopsy, endoscopic biopsy or necropsy confirmed the diagnosis of lymphosarcoma in all cats. Chemotherapy was instituted in 19 cats. Only 6 cats had a complete response to treatment. The results of this study indicate that ultrasonography is a valuable tool for the diagnosis of feline alimentary lymphosarcoma and that biopsies can be obtained under ultrasonographic guidance.     

Pasteurella haemolytica A1 and Bovine Respiratory Disease: Pathogenesis

The severe fibrinonecrotic pneumonia associated with pneumonic pasteurellosis usually results from colonization of the lower respiratory tract by Pasteurella haemolytica biotype A, serotype 1(A1). Despite recent research efforts, the authors lack a detailed understanding of the interactions and host response to P. haemolytica in the respiratory tract. The authors hypothesize that management and environmental stress factors or viral infection alters the upper respiratory tract (URT) epithelium allowing P. haemolytica to colonize the epithelium. Once the URT is colonized, large numbers of organisms enter the lung where they interact with alveolar macrophages. Endotoxin, released from the bacteria, crosses the alveolar wall where it activates pulmonary intravascular macrophages, endothelium, neutrophils, lymphocytes, platelets, complement, and Hageman factor leading to complex interactions of cells and mediators. It is the progression of this inflammatory response with neutrophil influx that is ultimately responsible for the pulmonary injury. Leukotoxin is a major virulence factor of P. haemolytica that allows it to survive by destroying phagocytic cells. At subcytolytic concentrations it may also enhance the inflammatory response by activating cells to produce mediators and release reactive oxygen metabolites and proteases.     

MAGNETIC RESONANCE IMAGING FEATURES OF MULTILOBULAR OSTEOCHONDROSARCOMA IN 3 DOGS

Three dogs with multilobular osteochondrosarcoma of the skull were evaluated using magnetic resonance (MR) imaging. Spin echo T1, T2, proton weighted and post contrast T1W images were obtained with a 1.5 Tesla magnet. The MR imaging findings were similar in all three dogs with mixed signal intensities in the T1W, T2W and proton weighted images and fairly large areas of contrast enhancement in the post contrast T1W images. The extent of brain and soft tissue involvement were well delineated and provided useful information concerning surgical planning. MR imaging provided a useful method of evaluating dogs with skull tumors.     

Intraperitoneal Circulation and Drainage in the Dog

The patterns of dispersion and drainage of a low viscosity, oil-based contrast medium within the peritoneal cavity were examined in 12 normal dogs. Intraperitoneal injection of contrast medium was cranial or caudal and drainage was by the sump-Penrose or open peritoneal method. Radiographs were made over a 96 hour period, before and after peritoneal drainage was established. Each dog was euthanatized and necropsied. The contrast medium was dispersed throughout the peritoneal cavity 15 to 30 minutes after cranial injection and 1 to 2 hours after caudal injection. Most of the contrast medium drained within 6 hours after open peritoneal drainage and within 24 to 48 hours after sump-Penrose drainage. At necropsy, there was complete encasement of all sump-Penrose drains and partial occlusion of all open peritoneal incisions by omentum adhered to the abdominal wound edges. Peritonitis was not grossly evident, but all dogs showed histologic evidence of an acute inflammatory reaction associated with the drain or wound edge.     

Determination of extractable and non-extractable radioactivity from prairie soils treated with carboxyl- and ring-labelled [14C]2,4-D

Ring- and carboxyl-labelled [¹⁴C]2,4-D were incubated under laboratory conditions, at the 2 g/g level, in a heavy clay, sandy loam, and clay loam at 85% of field capacity and 20 1C. The soils were extracted at regular intervals for 35 days with aqaeous acidic acetonitrile, and analysed for [¹⁴C]2,4-D and possible radioactive degradation products. Following solvent extraction, a portion of the soil residues were combusted in oxygen to determine unextracted radioactivity as [¹⁴C]carbon dioxide. The remaining soil residues were then treated with aqueous sodium hydroxide, and the radioactivity associated with the fulvic and humic soil components determined. In all soils there was a rapid decrease in the amounts of extractable radioacitivity, with only 5% of that applied being recoverable after 35 days. All recoverable radioactivity was attributable to [¹⁴C]2,4-D, and no [¹⁴C]-containing degradation products were observed. This loss of extractable radioactivity was accompanied by an increase in non-extractable radioactivity. Approximately 15% of the applied radioactivity, derived from carboxyl-labelled [¹⁴C]2,4-D, and 30% from the ring-labelled [¹⁴C]2,4-D was associated with the soil in a non-extractable form, after 35 days of incubation. After 35 days, less than 5% of the radioactivity from the carboxyl-labelled herbicide, and less than 10% of the ringlabelled material, was associated with the fulvic components derived from the three soils. Less than 5% of the applied radioactivities were identifiable with any of the humic acid components. It was considered that during the incubation [¹⁴C]2,4-D did not become bound or conjugated to soil components, and that non-extractable radioactivity associated with the three soil types resulted from incorporation of radioactive degradation products, such as [¹⁴C]carbon dioxide, into soil organic matter.     

How to perform transvenous electrical cardioversion in horses with atrial fibrillation

Electrical cardioversion of atrial fibrillation is a well-established technique for restoration of sinus rhythm in humans. While transthoracic cardioversion is more commonly used, transvenous electrical cardioversion (TVEC) has been reported as having higher efficacy at substantially lower energy levels. In horses, treatment of atrial fibrillation has essentially been limited to the administration of quinidine salts either orally or intravenously. TVEC provides an alternative to quinidine salts, especially for those animals in which quinidine is neither effective nor tolerated. The present report details this technique in horses, discusses possible complications of the procedure, and provides guidance for successful outcome. Still and video images are used to illustrate details with regard to TVEC techniques in horses. Please view supplemental material for the videos.     

Association of hyponatremia and hyperglycemia with outcome in dogs with congestive heart failure

Objective: To evaluate plasma sodium and glucose concentrations in dogs with congestive heart failure (CHF) prior to treatment and evaluate the differences between survivors and non‐survivors. Design: Retrospective study. Animals: Fifty‐nine dogs with CHF prior to receiving cardiac medication. Interventions: None. Measurements and main results: The mean plasma sodium concentration in dogs with CHF was below the reference range (144–156 mmol/L) and significantly lower (P=0.009) in non‐survivors (141±6 mmol/L) compared with survivors (147±4 mmol/L). The mean plasma glucose concentration was above the reference range (76–117 mg/dL) and significantly higher (P=0.004) in non‐survivors (128±52 mg/dL) compared with survivors (100±13 mg/dL). Forty‐four percent of non‐survivors had concurrent low plasma sodium and high plasma glucose concentrations, whereas no survivors had both abnormalities (P<0.0001). Conclusions: Lower plasma sodium and higher plasma glucose are associated with a worse outcome in dogs with CHF.     

Response of black, cranberry, kidney, and white bean to linuron

Dry bean producers in Ontario, Canada, have few herbicide options available for annual broad-leaved weed management and there is little information on the tolerance of dry bean to linuron. The tolerance of black, cranberry, kidney, and white bean to the pre-emergence (PRE) application of linuron at the rates of 0, 500, 1000, 1500, 2000, and 2500 g ai ha⁻¹ was evaluated in field studies conducted in 2005 and 2006 at Exeter and in 2006 at Ridgetown, Ontario. The four market classes differed in their response to linuron. Cranberry and kidney bean were more tolerant to the PRE application of linuron than black and white bean. Linuron applied PRE caused as much as 12% injury in cranberry and kidney bean, 47% injury in black bean, and 56% injury in white bean. Linuron applied PRE at 500–2500 g ai ha⁻¹ had no effect on the height of cranberry and kidney bean but decreased the height by 7, 8, and 15% in black bean and by 10, 13, and 23% in white bean at 1500, 2000, and 2500 g ai ha⁻¹, respectively. Linuron applied PRE at the rates evaluated did not cause any adverse affect on the yield of cranberry, kidney, and white bean but black bean yield was reduced by 16% at 2500 g ai ha⁻¹. Based on these results, there is not an adequate margin of crop safety for the PRE application of linuron in black and white bean at rates >1000 g ai ha⁻¹. However, there is a potential for the use of linuron PRE for weed management in cranberry and kidney bean at the rates evaluated.     

A NATURAL SYSTEM OF SOIL CLASSIFICATION

Definitions of natural classification are given which emphasize the importance of theory and concept in the construction of natural systems. The proposed system is based on two principles of soil formation. The first principle emphasizes the three-dimensional nature of soil bodies. The second principle, known as the Principle of Developmental Sequences, is concerned with stages of soil development. The many developmental sequences identified by pedologists are correlated by means of a small number of constituents which are lost and gained during soil formation. These constituents, in an order of eluviation/illuviation, are used to rank the properties on which the proposed system is based. Soil horizons are defined according to the ranked properties and the classes of the system are, in turn, defined in terms of the horizons, with the result that the central statement of the system is the Principle of Developmental Sequences.