Polymerase chain reaction analysis for viruses in paraffin-embedded myocardium from dogs with dilated cardiomyopathy or myocarditis.

OBJECTIVE: To perform polymerase chain reaction (PCR) analysis on paraffin-embedded myocardium from dogs with dilated cardiomyopathy (DCM) and dogs with myocarditis to screen for canine parvovirus, adenovirus types 1 and 2, and herpesvirus. SAMPLE POPULATION: Myocardial specimens from 18 dogs with an antemortem diagnosis of DCM and 9 dogs with a histopathologic diagnosis of myocarditis were evaluated. PROCEDURE: Paraffin-embedded myocardial specimens were screened for viral genome by PCR analysis. Positive-control specimens were developed from cell cultures as well as paraffin-embedded tissue specimens from dogs with clinical and histopathologic diagnoses of viral infection with canine parvovirus, adenovirus types 1 and 2, and herpesvirus. The histologic characteristics of all myocardial specimens were classified regarding extent, location, and type of inflammation and fibrosis. RESULTS: Canine adenovirus type 1 was amplified from 1 specimen from a dog with DCM. Canine parvovirus, adenovirus type 2, and herpesvirus were not amplified from any myocardial specimens. Histologic analysis of specimens from dogs with DCM revealed variable amounts of fibrosis; myocardial inflammation was observed in 1 affected dog. Histopathologic analysis of specimens from dogs with myocarditis disclosed variable degrees of inflammation and fibrosis. CONCLUSIONS AND CLINICAL RELEVANCE: Viral agents canine parvovirus, adenovirus types 1 and 2, and herpesvirus are not commonly associated with DCM or active myocarditis in dogs. Additional studies evaluating for nucleic acid from viruses that less commonly affect dogs or different types of infectious agents may be warranted to gain insight into the cause of DCM and myocarditis in dogs.

Radiofrequency catheter ablation of atrioventricular accessory pathways in 3 dogs with subsequent resolution of tachycardia-induced cardiomyopathy.

Incessant supraventricular tachyarrhythmias are known to result in myocardial dysfunction indistinguishable from idiopathic dilated cardiomyopathy by current testing methods. This tachycardia-induced cardiomyopathy (TICM), however, is uniquely reversible with adequate rhythm control. Two dogs were presented to The Ohio State University for incessant supraventricular tachycardia (SVT) and echocardiographic signs of dilated cardiomyopathy, later proven to be TICM. A 3rd dog presented for frequent paroxysms of SVT and syncope had echocardiographic signs of mild myocardial systolic dysfunction. All 3 dogs had inadequate rhythm control with multiple antiarrhythmic agents, and 1 dog suffered from recurrent left-sided congestive heart failure. Generalized cardiomegaly was found in 1 dog and left-sided dilatation without concurrent right-sided enlargement in 1 dog. Mild-to-severe left ventricular systolic dysfunction was confirmed echocardiographically in all dogs. A total of 4 atrioventricular accessory pathways (APs) were found during invasive electrophysiologic studies in these 3 dogs. All APs were successfully ablated with radiofrequency energy delivered through a thermistor-tipped catheter. Elimination of AP conduction, and thus orthodromic atrioventricular reciprocating tachycardia, resulted in resolution of all clinical and echocardiographic evidence of TICM in these dogs. This result confirms that the cardiomyopathy was, in fact, reversible TICM. All cardiovascular medications were discontinued, and no complications occurred during a 15-25-month follow-up period.

Tracheobronchial mucoepidermoid carcinoma in childhood and adolescence: case report and review of the literature.

In children and adolescents, primary neoplasms of the tracheobronchial tree and lungs are rare, with most tumors involving the respiratory system being metastatic, small, blue cell tumors of childhood. Of the primary pulmonary neoplasms, most are malignant with mucoepidermoid carcinoma representing about 10% of these malignant tumors. We present an 8-year-old Hispanic male with hemoptysis and several episodes of pneumonia which initially was thought to be infectious upon biopsy during bronchoscopy, but proved to be mucoepidermoid carcinoma of the tracheobronchial tree by microscopic examination during an open lung biopsy. This rare tumor is more common in adults than in children, and infrequently presents with hemoptysis. Mucoepidermoid tumors of the tracheobronchial tree carry a more favorable prognosis in children than adults. In the adult population, the overall mortality is slightly less than 30%. In contrast, of the 31 reported cases of tracheobronchial mucoepidermoid carcinoma in pediatrics, all children are free of tumor involvement with a mean follow-up period of 5.8 years (range, 0.7-21 years). Based upon the available clinical outcome and survival data, it would appear that tracheobronchial mucoepidermoid carcinoma may be successfully managed by surgical intervention alone in children and adolescents.

Biochemical characterization of a glycoprotein required for rhinovirus attachment.

Human rhinoviruses attach to specific receptors located on the surfaces of host cells as a first step in viral infection. A 90-kDa cell surface protein was previously shown to be involved in the attachment of human rhinoviruses to susceptible cells (Tomassini, J. E., and Colonno, R.J. (1986) J. Virol. 58, 290-295). Digestion of purified receptor protein with various glycosidases revealed that 30% of its molecular mass was comprised of complex-type oligosaccharides, one-third being contributed by sialic acid. The presence of sialic acid was confirmed by demonstrating that wheat germ lectin can inhibit the attachment of rhinoviruses to host cell membranes, while lectins of other sugar specificities had no effect. The oligosaccharides were shown to be N-linked by tunicamycin treatment of host cells and by N-glycanase digestion. Seven N-linked glycosylation sites were detected by partial digestion of the receptor oligosaccharides with N-glycanase. Native receptor protein had an isoelectric focusing point of 4.2, compared to 5.3 for the deglycosylated protein. Studies of virus and antibody binding to neuraminidase-treated host cell membranes suggested that although carbohydrates may be involved in host-virus interaction, the receptor carbohydrate is not the predominant component of the cellular receptor site.

Pulmonary lavage in a patient in status asthmaticus receiving mechanical ventilation: a case report.

Allergy and/or contraindications for theophylline and adrenergic drugs can be a life-threatening problem for patients with respiratory failure resulting from status asthmaticus. Mucous plugs and secretions in smaller bronchi can further complicate the problem. A patient in status astmaticus complicated by mucous impaction is described in whom pulmonary lavage was performed through a flexible fiberoptic bronchoscope using a solution containing 250 ml normal saline, 30 ml 20% acetylcysteine, 0.5 ml Bronkosol and 125 mgm Solu-Medrol. Lavage was done twice at 24-hour intervals; extubation was accomplished within 48 hours after first lavage. This treatment resulted in remarkable improvement and proved to be life saving. The result suggests that this procedure is a useful therapeutic method and can be life saving in selected patients with respiratory failure.