Constrictive pericardial disease in the dog

The clinicopathologic features of constrictive pericardial disease in 13 dogs were reviewed. The causes were infection (3 dogs), metallic foreign body (1 dog), and idiopathic (9 dogs). Owner complaints included abdominal enlargement, tachypnea, weakness or syncope, exertional fatigue, and weight loss. Ascites and jugular venous distention were consistently observed, whereas abnormalities of arterial pulses and heart sounds were variable and inconsistent. Diminished QRS voltages were common. Mild to moderate cardiomegaly, rounding of the cardiac silhouette, and variable and nonspecific angiographic findings were frequently observed. Cardiac catheterization consistently showed elevation and equilibration of atrial and ventricular diastolic pressures, but a prominent early diastolic (y) descent was uncommon. Fibrosis was confined to the parietal pericardium in 8 dogs, and included the epicardium in 5 dogs. Parietal pericardectomy was successful in relieving the syndrome in 6 of 10 dogs. Pulmonary thrombosis was the most common cause of early postoperative mortality.     

Alterations in coagulation and hemograms of horses given endotoxins for 24 hours via hepatic portal infusions

This experiment was designed to establish a model for the study of gastrointestinal disturbances as a result of prolonged endotoxin uptake in the horse. The hepatic portal vein of 7 horses was catheterized (through flank incisions) to give chronic hepatic portal infusions of lipopolysaccharide (LPS, endotoxin). Lipopolysaccharide was infused at a rate of 1 microgram/kg of body weight/hr for 24 hours. Two of the horses were infused with saline solution for 12 hours before LPS infusions were given. Lipopolysaccharide was shown to affect behavior and hematologic and coagulation values. The 1st hour was critical for the LPS-infused horses; yet by 4 hours, the horses had apparently become refractory to continued infusion of LPS. During the 1st hour, all horses collapsed without an accompanying hypotension. A decrease in polymorphonuclear leukocytes (neutrophils) was seen during this time and was accompanied by a shortening of the recalcification tests, 1-stage prothrombin time, and activated partial thromboplastin time. There was an increased concentration of circulating fibrinogen/fibrin degradatory products. All of the LPS-infused horses showed signs of hoof discomfort and either stood with the 4 feet together beneath the body or continually shifted their weight from one front foot to the other. Hoof temperature decreased approximately 3 degrees (C) during this time and remained decreased for the duration of the experiment.     

PNEUMOPERICARDIOGRAPHY IN THE NORMAL DOG

To define the normal radiographic anatomy of the canine heart and pericardial space as outlined by air, pneumopericardiography was performed in ten normal, anesthetized dogs using a percutaneously introduced pericardial catheter. Room air was injected to produce pneumopericardiums without causing cardiac tamponade, and radiographs were obtained using a vertical beam with the dogs positioned in right lateral (RLAT), left lateral(LLAT), dorsal (VD), and ventral (DV) recumbency. Selective and nonselective angiocardiography was used to confirm the identity of the outlined structures. The RLAT and LLAT positions provided more information than the DV or VD positions. Pericardial air consistently outlined a distinct interventricular sulcus and the recesses around the aorta and pulmonary artery. The right auricle, outlined along the cranial heart border ventral to the ascending aorta in both RLAT and LLAT positions, varied considerably in size. The RLAT position best outlined structures to the left of midline, including the left auricle, interventricular sulcus, outflow region of the right ventricle, and the origin of the pulmonary artery. The LLAT position best demonstrated structures to the right of midline, including the right atrium, proximal part of the cranial and caudal vena cavae, and ascending aorta. The considerable range of normal variation between dogs in this study must be considered in the interpretation of clinical pneumopericardiograms.     

The reactivation of carbamate-inhibited cholinesterase,kinetic parameters

The rates of spontaneous regeneration or decarbamylation of fly-head and bovine erythrocyte cholinesterase inhibited by methyl- and dimethylcarbamic acid esters were determined under different conditions of pH, salt concentrations, and temperature using Sephadex gel filtration as a means of isolating the carbamylated enzyme. The pH-rate profiles for decarbamylation of the two cholinesterases for both methyl- and dimethylcarbamylated enzyme had maximum rates at pH 8.5–8.9 for bovine erythrocyte and pH 8.1–8.5 for fly-head cholinesterase. Imidazole, hydroxylamine, and inorganic salts did not alter the decarbamylation rate. Values for the energy of activation for the decarbamylation reaction indicate a somewhat unstable and more reactive carbamylated enzyme for bovine cholinesterase compared to fly-head cholinesterase, but entropy factors are more favorable for decarbamylation in the latter. Regeneration rates in deuterium oxide for both enzymes and both methyl- and dimethylcarbamates were approximately six to seven times slower than in water, indicating a secondary isotope effect. A mechanism for decarbamylation consistent with the data is cited.     

Histochemical changes in skeletal muscles of four male horses with neuromuscular disease

Skeletal muscle biopsy specimens were taken from 4 male horses with neuromuscular disease such as myotonia congenita, chronic myositis, exertional rhabdomyolysis, and shivers. Histologic and histochemical techniques were used to evaluate skeletal muscle morphologic features and fiber-type population, size, and area, as well as muscle enzyme activities (acid phosphatase, alkaline phosphatase, and esterase). A histochemical and histologic profile were described for each muscle biopsy specimen.     

Cerebrospinal nematodiasis in pheasants

Infection with larvae of Baylisascaris procyonis, the raccoon ascarid, was the cause of neurologic disease affecting young pheasants on a commercial pheasant ranch in Wisconsin. The disease was chronic and insidious, affecting 1% to 2% of the birds over a period of 2 years. Histologic lesions in the brain consisted of multifocal areas of necrosis and inflammation associated with Baylisascaris larvae. Onset of the disease at the farm correlated with introduction of chopped straw as bedding for the young birds. The straw was from a neighbor's barn and was contaminated with raccoon feces that contained B procyonis eggs. Cessation of use of the contaminated straw resulted in cessation of CNS disease in pheasants on the ranch.