Antibody to acetylcholine receptor in canine and human myasthenia gravis: differential cross-reactivity with human and rabbit receptor.

Anti-acetylcholine receptor (AChR) antibody (ab) was found in the serum of a dog with acute myasthenia gravis (MG) by the use of Cowan 1 strain Staphylococcus aureus to bind radiolabeled anti-AChR ab-AChR immune complexes. Fifteen months later, when the dog was in remission, there was only a very low level of the anti-AChR ab. These observations strengthen the contention that anti-AChR ab is important in the pathophysiology of myasthenia gravis. Higher titers of the canine ab were measured with rabbit than with human AChR, whereas 17 human MG sera, selected to represent a wide range of anti-AChR ab titers, were all more reactive with human AChR. The degree of cross-reactivity of human anti-AChR ab with rabbit AChR varied widely, indicating a heterogeneous population of anti-AChR ab molecules in human myasthenia gravis sera.

Long-term clinical management of right-to-left ("reversed") patent ductus arteriosus in 3 dogs.

A small number of dogs with patent ductus arteriosus (PDA) have right-to-left flow of blood through the ductus, leading to polycythemia and clinical signs associated with hyperviscosity. Three dogs with right-to-left-shunting PDA are described. Treatment consisted solely of phlebotomy, performed on an outpatient basis when indicated by exacerbation of clinical signs, for a total of 11-68 times on each dog. Each treatment entailed the removal of a mean of 19% (maximum 28%) of circulating blood volume, divided into 2 phlebotomies several hours apart, without intravenous fluid replacement. Subjectively, marked clinical improvement was noted. Intermittent clinical signs decreased in frequency and severity in all dogs. Adverse effects were rare (1 for 98 phlebotomies) and reversible. Dogs lived > 2 to > 8 years during treatment. Outpatient phlebotomy without fluid replacement was safe, and was associated with subjective improvement and prolonged survival in these dogs.

Diphacinone-induced coagulopathy in the dog.

Five cases of coagulopathy caused by consumption of indanedione (diphacinone)-based rodenticides are reported. In each case, acute onset of lethargy and respiratory distress were the predominant initial clinical signs. Thoracic radiography revealed pulmonary edema, pleural effusion, and/or pericardial effusion as consistent findings. Laboratory evaluations confirmed coagulopathies that responded to vitamin K1 therapy.

Effects of enalapril maleate on survival of dogs with naturally acquired heart failure. The Long-Term Investigation of Veterinary Enalapril (LIVE) Study Group.

OBJECTIVE: To test the long-term effect of enalapril maleate treatment on progression of clinical signs of heart disease in dogs with moderate or severe naturally acquired heart failure associated with chronic degenerative mitral valvular disease (mitral regurgitation [MR]) or dilated cardiomyopathy (DCM). DESIGN: Prospective multicenter study. ANIMALS: 110 dogs enrolled at 15 locations in the United States. PROCEDURE: All dogs enrolled in this study were maintained on their randomly allocated treatment regimen until death, treatment failure (deterioration of condition requiring additional medication), or termination of the study. All dogs entered in the study received standard heart failure treatment (furosemide with or without digoxin). Statistical analysis (log-rank test) was performed to compare the distribution of number of days in the study between dogs that received placebo tablets and dogs that received enalapril tablets. RESULTS: When dogs with MR and DCM were grouped together, mean number of days until treatment failure was significantly different between those receiving enalapril and those given placebo tablets (157.5 and 77.0 days, respectively). For dogs with MR, mean number of days until treatment failure was significantly different between those receiving enalapril and placebo tablets (159.5 and 86.6 days, respectively). Mean number of days until treatment failure among dogs with DCM receiving enalapril and placebo tablets was 142.8 and 56.5, respectively. CLINICAL IMPLICATIONS: Use of enalapril in combination with standard treatment (diuretics with or without digoxin) appears to be beneficial over an extended period, compared with standard treatment alone.

Ordering diagnostic tests in cardiovascular disease.

All heart patients should have an electrocardiogram, radiographs of the chest, and blood work done in addition to a complete history and physical examination. In ordering diagnostic tests, the real point is to understand the rationale for each test ordered, what information may be expected from the test, and if there is a justifiable reason for each test considering the factors involved.