Buchanan, James W
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Publication Mineralization of Short Term Pericardial Cardiac Patch Grafts(1984-01-27) Buchanan, James W; Frasca, P.; Soriano, R. Z; Dunn, J. M; Marmon, L.; Buchanan, Sarah A.; Melbin, J.; Chang, S. H; Golub, E. E; Shapiro, I. MGlutaraldehyde fixed patch grafts of bovine pericardium were implanted in myocardial windows in young (3-4 months old) sheep. The samples were retrieved after one to three weeks for study with scanning electron microscopy (SEM) and energy dispersive x-ray microanalysis (EDX). A layer of porous material (pseudoneointima, PNI), consisting mostly of a dense mesh of fibers interspersed with blood cells, was noted to form on the blood contacting surface of the graft. Four distinct sets of mineralization were noted in the retrieved grafts: (1) at the blood contacting surface of the PNI; (2) within the PNI at the junction between layers of PNI with differing densities; (#) near the junction of PNI and pericardium (but in the PNI); and (4) within the pericardium. In both the PNI and pericardium the mineral was shown by EDX analysis to contain both calcium and phosphorous indicating the mineral to be a calcium phosphate. Mineralization in the PNI differed from that in the pericardium; in the PNI it was deposited in discrete regions and apparently in association with thrombi while in the pericardium it was distributed diffusely within the collagen matrix, which may influence its formation.Publication Chronic Valve Disease and Left Atrial Splitting in the Dog [Dissertation](1967) Buchanan, James WAge, sex, and breed evaluations of 392 dogs with chronic valve disease (CVD) from a survey of 4,831 dogs revealed a predominance of CVD in purebred male dogs. Male Cocker Spaniels were most frequently affected. A questionnaire survey concerning aspects of medical history, environment, behavior, and survival was made 3-5 years after initial clinical examinations on 471 dogs. This study revealed no marked differences between dogs with CVD and dogs with no heart disease, except that dogs with CVD more often had signs of congestive heart failure. Endocardial and endomyocardial splitting of the left atrium occurred in 30 dogs with CVD; primarily in males of the Dachshund and Cocker Spaniel breeds. Left atrial perforation in several of the cases caused hemopericardium or acquired atrial septal defects which could be diagnosed by clinical means. The cause of splitting was considered to be left atrial dilatation with left atrial degeneration playing primarily a permissive role. Lipid deposition in the endocardium and ruptured chordae tendineae was found in preliminary frozen section studies. A method of postmortem cardiotomy was developed which permitted recognition of spontaneously ruptured cordae tendineae were frequently found in dogs with severe chronic valve disease with or without left atrial splitting. The Dachshund, Cocker Spaniel, and Beagle breeds in varying order constituted the three most common breeds with CVD, left atrial splitting or the intervertebral disc syndrome. This finding was suggestive of an underlying connective tissue disorder predominant in those breeds which have been classified by others as belonging to a "chondrodystrophoid" group. Radiographic studies of dogs with left atrial enlargement revealed a characteristic bulge in the dorsoventral cardiac silhouette caused by dilatation of the left atrial appendage. This was most apparent in dogs with left atrial splitting. Clinical and pathological studies on 60 "hyperimmune" dogs from which blood was withdrawn by cardiocentesis for immune serum production revealed serious heart disease in nearly all dogs. This was considered the results of weekly cardiocentesis for periods up to three years rather than the results of repeated vaccinations during this time.Publication Changing Breed Predispositions in Canine Heart Disease(1993-12-01) Buchanan, James WBreed predispositions for some types of congenital heart disease were recognized 30 years ago and led to breeding experiments that confirmed the genetic transmission of specific congenital heart defects in most instances. As a result, certain breeds were associated with certain diseases, and this became a legitimate consideration in the differential diagnosis of some abnormalities in the absence of more definite diagnostic studies. As an example, a significant systolic murmur in a young Newfoundland dog means sub-aortic stenosis (SAS) until proven otherwise. The diagnosis of SAS is usually confirmed by Doppler echocardiography or angiocardiography. Although cardiologists take breed into consideration, they still rely on proper examination and appropriate diagnostic procedures; however, practitioners are comes pressed to give opinions on the likelihood of particular diagnoses and prognoses without benefit of a full work-up. In this setting, knowledge of new and changing breed predispositions can be helpful. In recent years, some defects and new breeds have been found to be overrepresented in cardiology clinics across the country. All practitioners need to be alert in order to recognize new breed predispositions and counsel breeders accordingly. Of particular note is the rising frequency of SAS in Golden Retriever and Rottweiler dogs. The purpose of this presentation is to describe changing breed predispositions that have been observed in recent years and share the results of a recent tabulation of data at our institution as well as 1987- 1989 data in the national Veterinary Medical Data Base (VMDB) at Purdue University.Publication Left Atrial Paraganglioma in a Dog: Echocardiography, Surgery, and Scintigraphy(1998-03-01) Buchanan, James W; Boggs, Lynne S; Dewan, Stephan; Regan, Joan; Myers, Nathaniel CPrimary tumors of the left atrium are uncommon in dogs and tumor-specific diagnoses have been made only at necropsy. No reports have been found in which the diagnosis was confirmed antemortem and the tumor removed surgically. This report describes a case of obstructive paraganglioma in the left atrium of a dog and long-term survival after surgical removal of most of the tumor using cardiopulmonary bypass. Subsequently, scintigraphy demonstrated the presence of somatostatin receptors in residual tumor in the left atrium. The latter technique may be of value in establishing a definitive diagnosis in future cases of chemodectoma, extra-adrenal paraganglioma, or adrenal paraganglioma (phechromocytoma).Publication Tracheal Signs and Associated Vascular Anomalies in Dogs With Persistent Right Aortic Arch(2004-07-01) Buchanan, James WMedical records of 55 dogs with 1 or more vascular rings around the esophagus and trachea were reviewed to determine the nature and frequency of related vascular anomalies and to determine the reliability of tracheal deviation on radiographs for the diagnosis of persistent right aortic arch (PRAA). Fifty-two (95%) of the 55 dogs had PRAA. Of the 52 dogs with PRAA, 44% had coexisting compressive arterial anomalies: 17 had retroesophageal left subclavian artery and 6 had double aortic arch with atretic left arch. Characteristic tracheal deviation was consistently present in dogs with PRAA. Moderate or marked focal leftward curvature of the trachea near the cranial border of the heart in dorsoventral (DV) or ventrodorsal (VD) radiographs was found in 100% of available radiographs of 27 dogs with PRAA. Moderate or marked focal narrowing of the trachea also was noted in 74% of DV or VD radiographs and 29% of lateral radiographs of the dogs. Tracheal position in 30 of 30 dogs with megaesophagus and 62 of 63 control dogs was midline or rightward in VD or DV radiographs. Histology in a neonatal dog with PRAA revealed evidence of tracheal deviation and compression even before birth. Focal leftward deviation of the trachea near the cranial border of the heart in DV or VD radiographs is a reliable sign of PRAA in young dogs that regurgitate after eating solid food, and contrast esophagrams are not necessary to confirm the diagnosis of vascular ring compression.Publication Familial Dilated Cardiomyopathy of Young Portuguese Water Dogs(1999) Dambach, Donna M; Lannon, Anne; Sleeper, Meg M; Buchanan, James WA novel dilated cardiomyopathy (DCM) in 12 related Portuguese Water Dogs was identified by retrospective analysis of postmortem and biopsy case records. Male and female puppies born to clinically healthy parents typically died at 13 (± 7.3) weeks of age (range, 2–32 weeks) because of congestive heart failure. Puppies died suddenly without previous signs or with mild depression followed by clinical signs of congestive heart failure 1–5 days before death. There was no sex predilection. The hearts were enlarged and rounded, with marked left ventricular and atrial dilation. No other significant structural cardiac defects were noted. The histologic changes in the myocardium were diffuse and characterized by myofibers of irregular sizes separated by an edematous interstitium. The myofibers had multifocal swollen, cleared segments often involving perinuclear areas that contained granular, phosphotungstic-acid-hematoxylin-positive material consistent with mitochondria. There was loss of the cross-striation pattern, and intercalated discs were difficult to identify. There was no evidence of concurrent myocardial fibrosis; rare chronic inflammatory infiltrates were noted in one dog. Noncardiac skeletal muscles were not affected. The underlying cause is unknown. From the pedigree analysis, an autosomal recessive pattern of inheritance is suspected. Based on the histologic findings, this DCM is most likely due to an underlying molecular (biochemical or structural) defect. The early onset and rapid progression of the disease makes this a clinically distinctive form of canine DCM.Publication Infection and Twiddler Syndrome in a Dog With Addison's Disease, Complete Heart Block, and Wandering Artificial Pacemakers(1990-02-01) Buchanan, James W; Hill, Richard CThird-degree heart block developed in an obese seven-year-old dog with adrenal cortical failure. After three days of extensive medial therapy and use of a temporary transvenous pacemaker, a transthoracic permanent pacemaker was implanted in the usual paracostal location. After two years of normal function, the pulse generator suddenly migrated to a ventral location in the flank and became surrounded by an abscess. Intermittent pacing failure ensued. Medical therapy with antibiotics failed to eliminate infection until the infected pacemaker and site were excised surgically. A new pacemaker was placed on the opposite side and functioned well for two months. Subsequent migration and rotation of the new pacemaker led to spiral twisting of the lead and dislodgment of the corkscrew electrode from the myocardium in a syndrome analogous to Twiddler's syndrome in man. The dog presently is 10 years old and asymptomatic with a nonpaced ventricular rhythm of 60 beats per minute and an usual chest radiograph.Publication Pathogenesis of Single Right Coronary Artery and Pulmonic Stenosis in English Bulldogs(2001-03-01) Buchanan, James WEnglish Bulldogs are the most common breed to have pulmonic stenosis. Previous studies showed that this congenital heart abnormality in Bulldogs frequently is caused by a circumpulmonary left coronary artery originating from a single right coronary artery. Fetal anasarca also occurs often in Bulldogs and might represent congestive heart failure, but the cause is unknown. To determine if fetal anasarca is associated with a coronary anomaly and pulmonic stenosis, major coronary arteries were studied in 6 bulldog puppies with fetal anasarca. Five of the puppies had normal coronary arteries, and this led to the conclusion that fetal anasarca usually is not associated with major coronary abnormalities or pulmonic stenosis. The 6th puppy had single right coronary artery with circumpulmonary left coronary artery and moderate subvalvular pulmonic stenosis. Serial section histology suggests that the underlying cause of this syndrome is malformation of the left aortic sinus (of Valsalva) and inversion of the proximal segment of the left main coronary artery.Publication Clinico-Pathologic Conference: Chronic Nephritis in a Bull(1961-10-15) Marshak, Robert; Buchanan, James W; Sauer, R. MPublication Etiology of Patent Ductus Arteriosus in Dogs(2003-03-01) Buchanan, James W; Patterson, Donald FPatent ductus arteriosus (PDA) is the most common congenital heart disease in dogs and usually causes heart failure and death unless corrected at a young age. Previous histologic studies in a line of dogs derived from Miniature Poodles with hereditary PDA identified varying degrees of hypoplasia and asymmetry of ductus-specific smooth muscle and the presence of aortalike elastic tissue in the ductus wall sufficient to cause patency. To determine if similar structural abnormalities cause PDA in other dogs, serial-section, 3-dimensional histology of ductal architecture was studied in 8 non-Poodle purebred dogs with PDA with no immediate family history of PDA. Morphologic abnormalities were observed in 7 of 8 dogs with PDA and essentially were the same as those in dogs known to have a hereditary form of PDA. These findings suggest that apparently sporadic PDA in these breeds is caused by a genetic defect in the structure of the ductus arteriosus that is similar or identical to that in the Poodle. The relatives of dogs with PDA, particularly parents, offspring, and siblings, should be screened for evidence of PDA. Dogs with PDA should not be used for breeding, regardless of breed.