Buchanan, James W

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Now showing 1 - 10 of 24
  • Publication
    Persistent Left Cranial Vena Cava in Dogs: Angiocardiography, Significance, and Coexisting Anomalies
    (1963) Buchanan, James W
    Persistent left cranial venae were observed in angiocardiograms of 3 dogs at the University of Pennsylvania Veterinary Hospital. Although this vessel seldom has clinical significance, it is hoped this report will spare others the confusion caused by the first case in this series. These 3 dogs and 5 out of 7 others had significant cardiovascular anomalies in addition to persistent left cranial venae cavae.
  • Publication
    Aortic Embolism in Cats: Prevalence, Surgical Treatment and Electrocardiography
    (1966-10-29) Buchanan, James W; Baker, Gordan J; Hill, John D
    Aortic embolism (caudal arterial thromboembolism) was diagnosed over a four-year-period in 14 out of 2,000 cats in a hospital clinic population (7/1,000). Including 35 cases reported in the literature, the average age of 50 cats with aortic embolism was 6-8 years (range one to 16 years). Of these, 37 were males and 13 were females. Endocarditis with thrombosis was the most frequently observed cause of aortic embolism, although aortic arteriosclerosis was reported in one cat. The clinical and pathological features of aortic embolism in five cats are described in this report. In electrocardiograms of four of these, arrhythmias or conduction disturbances were recorded. Intact emboli in the aorta and external iliac arteries were removed by abdominal aortic embolectomy in two cats within hours after the onset of posterior paralysis. Death resulted in one case from cardiac complications and in the other by euthanasia at the later date because of probably recurrent aortic embolism. In the other three cases, multiple sections of the aorta with the embolus in situ were examined, but no microscopic changes in the aortic wall were noted. Surgical removal of an aortic embolus is technically and economically feasible and is considered the treatment of choice when treatment is requested within hours after the onset of clinical signs. Although embolectomy can yield a good immediate result; the long range justification for such therapy requires further evaluation, since recurrent embolization may develop.
  • Publication
    Changing Breed Predispositions in Canine Heart Disease
    (1993-12-01) Buchanan, James W
    Breed 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
    Clinico-Pathologic Conference: Chronic Nephritis in a Bull
    (1961-10-15) Marshak, Robert; Buchanan, James W; Sauer, R. M
  • Publication
  • 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. M
    Glutaraldehyde 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
    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 C
    Third-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
    Spontaneous Arrhythmias and Conduction Disturbances in Domestic Animals
    (1965-09-08) Buchanan, James W
    Most of the common arrhythmias and conduction disturbances have been reported in domestic mammals. Prevalence data, however, are not available from unselected population samples, and little information is at hand on long-term studies of individual cases. A discussion of some of these disturbances, therefore, must necessarily rely more heavily upon clinical impression than is desirable. Data have been published on normal electrocardiograms in different species, which, coupled with published case series, individual case reports, and observations made at the Heart Station of the University of Pennsylvania School of Veterinary Medicine, provide the basis for this presentation. This information suggests that certain arrhythmias and conduction disturbances occur commonly in some species and should be regarded as normal variants. In animals, departures from the normal regular sinus rhythm characteristic of adult humans apparently result from a relatively greater vagal influence on the cardiac pacemaker and conduction tissues. This certainly accounts for respiratory sinus arrhythmia in dogs. In horses, high resting vagal activity is considered accountable for sinus arrhythmia (respiratory and non-respiratory), wandering pacemaker, varying P-R interval, SA block, and incomplete AV block with dropped beats. Although these arrhythmias and conduction disturbances may occur with primary heart disease, or disease primarily affecting vagal activity, their frequent occurrence in the absence of detectable heart disease and also their disappearance with increased heart rate following exercise, excitement, or atropine, support the view that vagal activity rather than primary heart disease accounts for the majority of occasions in which they are observed. Frequently, more than one of the preceding arrhythmias are observed in one individual in the same or subsequent tracings; therefore frequency data often reflect some overlapping. It is useful, however, to present them individually when discussing more specific information.
  • Publication
    A Case of Pulmonic Stenosis With Single Coronary Artery in a Dog
    (1989) Buchanan, James W; Minami, Takeo; Wakao, Yoshito; Muto, Makoto; Watanabe, Toshifumi; Suzuki, Tatsuo; Takahashi, Mitsugi
  • Publication
    Morphological Observations of Mineralizing Pericardium Cardiac Grafts
    (1985) Buchanan, James W; Frasca, P.; Soriano, R. Z; Dunn, J. M; Marmon, L.; Buchanan, Sarah A.; Melbin, J.; Golub, E. E; Shapiro, I. M
    Pericardial patch grafters were implanted in the hearts of young sheep for periods ranging from two to 120 days. Explants seven to 21 days old revealed the formation of a "pseudoneointima" (PNI) on the blood contacting surface of the pericardium. The PNI was more heavily mineralized than the pericardium. Mineralization was most intense on the blood contacting surface of the PNI and on the chamber surface of the pericardium. After three weeks of implantation, the PNI was much thinner and was organized into a thin fibrous capsule without any signs of mineralization. In the pericardium, mineral deposits were seen in fibroblasts. Moreover, cell-related mineralization was evident prior to calcification of the surrounding collagen matrix