Robert W. Prichard

The development of pigeon strains with selected atherosclerosis characteristics

Abstract Parental pairs of White Carneau, Show Racer, and F 2 (progeny of F 1 crosses between White Carneau and Show Racer) pigeons were identified according to specific features of the atherosclerosis of their offspring. Progeny were evaluated for atherosclerotic variables after being fed a diet containing 0.5% cholesterol for 6 mo. No significant differences were seen in the degree of hypercholesterolemia between breeds; however, within breeds all males had significantly higher serum cholesterol concentrations than females. Aortic atherosclerosis was more severe in White Carneau than in Show Racer or F 2 with F 2 pigeons being intermediate in the response. All autopsied progeny dying during the experiment showed more aortic and coronary atherosclerosis than their surviving sibs. Likewise, there was more coronary and aortic atherosclerosis in pigeons with myocardial infarcts found when they were killed at the end of the experiment. Aortic root and coronary artery atherosclerosis were assessed as important causative factors in myocardial infarction. Based on the atherosclerotic characteristics of progeny, the following strains have been selected. 1. 1. A strain of White Carneau with severe aortic atherosclerosis having mean aortic cholesterol concentrations of 60.42 mg/g aorta. 2. 2. A strain of Show Racer with very little aortic atherosclerosis having a mean aortic cholesterol concentration of 2.40 mg/g aorta. 3. 3. A strain of F 2 with concomitant severe coronary artery atherosclerosis (mean coronary artery index of 38) and very little aortic atherosclerosis (mean aortic cholesterol concentration of 6.13 mg/g aorta). 4. 4. A Show Racer and an F 2 strain with a frequency of myocardial infarction of 43 and 60%, respectively.

Interactions Among Dietary Fat, Protein, and Cholesterol in Atherosclerosis-Susceptible Pigeons

Atherosclerosis-susceptible pigeons fed cholesterol developed coronary atherosclerosis much more frequently than pigeons maintained on a cholesterol-free diet. Fewer of the cholesterol-fed pigeons fed a low protein diet developed coronary atherosclerosis than did cholesterol-fed pigeons on a high protein diet. Corn oil decreased the frequency of coronary atherosclerosis in cholesterol-fed pigeons. Limited evidence suggests that the coronary arteries and aortae in noncholesterol-fed birds are independent of each other in their susceptibility to atherosclerosis.

Synthesis of squalene and sterols by isolated segments of human and pigeon arteries

Abstract The ability of isolated arterial segments from man and pigeon to synthesize squalene and sterols from dl -mevalonate-2-14C has been studied by an in vitro perfusion technique. Following a 4-hour perfusion, more than 99% of the lipid radioactivity was contained in two major fractions after chromatography on alumina. The less polar fraction, accounting for 30–60% of the total lipid radioactivity in arterial segments from pigeon and man respectively, was shown to be more than 95% squalene. Squalene synthesis in the pigeon was positively and significantly correlated with the severity of atherosclerosis. Because of the highly variable postmortem interval, no such correlation was attempted for human arterial segments. The polar fraction from the alumina column, although possessing properties similar to cholesterol, contained on the order of 1% cholesterol when purified through the dibromide. The identity of the major portion of radioactivity in this fraction remains unknown.

Intracardiac Myxomas: Twenty-year Echocardiographic Experience With Review of the Literature

We reviewed the echocardiograms of 35 patients with intracardiac myxomas. Patient data were combined from two geographically distant laboratories. No significant variations in the patient profiles were encountered. Most patients were white (33 of 35) with a mean age of 45 years. The diagnosis was suspected on clinical grounds alone in only six of 35 patients before the echocardiogram was done. M-mode recordings were the primary echocardiographic modality available in the first 16 patients, whereas two-dimensional studies were also done in the others. Continuous and pulsed wave Doppler echocardiography were added in eight of the most recent studies. In one patient color flow imaging from both transthoracic and esophageal approaches was possible to better visualize a large left atrial tumor. Thirty-three patients had solitary tumors (29 left atrial, three right atrial, and one left ventricular), and two had multiple tumors. The most characteristic finding, as expected, was the demonstration of abnormal mass echoes produced by the myxoma tissue. Several interesting features not previously emphasized in the literature included abnormal notching of the interventricular septum and posterior left ventricular wall probably produced by displacement from the larger mobile left atrial tumors dropping into the mitral sleeve. This was best appreciated by the M-mode recordings. In one patient with an associated atrial septal defect, movement of the tumor into the defect appeared to alter the expected downward displacement into the mitral orifice. In the patients who were studied by two-dimensional, Doppler, or color flow imaging, tumor movement was evidenced by abnormal frequency shifts, and dispersion of flow around the tumor mass was readily appreciated. Surgical removal was performed in all patients. Follow-up echocardiograms were done postoperatively ranging up to 17 years. Recurrent tumors occurred in two patients, both of whom had congenital myxomas. Echocardiography is proving to be an unparalleled tool in the diagnosis of intracardiac tumors.

ATHEROSCLEROSIS IN SOME SPECIES OF NEW WORLD MONKEYS

Nonhuman primates have recently gained considerable interest as animal models for the study of atherosclerosis. This interest has occurred because these animals share with man taxonomic classification as Primates and because the naturally occurring and induced lesions of atherosclerosis bear a striking resemblance to the lesions of young human beings. Because of the taxonomic classification of the nonhuman primates, it is generally considered that data obtained from experiments on their atherosclerosis might be more directly relevant to an understanding of the disease process in human beings. The extent to which this general notion is true must await the accumulation of larger amounts of data on primate atherosclerosis and on the testing in human beings of generalizations made from these data. Of the nonhuman primates, the Old World monkeys have been the most extensively used in atherosclerosis research. In recent years, however, investigations of the New World monkeys as experimental subjects in atherosclerosis has greatly increased. This increased attention has resulted because of their ready availability on this continent, their susceptibility to naturally occurring atherosclerosis and the ease by which the disease can be aggravated by diet, the rarity of tuberculosis among these animals, and the apparent lack of simian B-virus infections. The purpose of this paper is to review some of the characteristics of atherosclerosis in New World monkeys.

A survey of first-year pathology residents: Factors in career choice

Pathology has become less attractive to US medical graduates by every measure available to us. In 1981, 2.3 per cent of US medical school seniors planned a pathology career; by 1986, a steady decline had reached 1.6 per cent. In absolute numbers, adjusted for the response rate to the AAMC questionnaire, this means that the 290 seniors entering pathology in 1981 had fallen to 205 by 1986. FMGs enter pathology through the matching program in greater numbers than any other specialty. Our data show that slightly less than a third of current first-year pathology residents are FMGs, mainly from Caribbean and Mexican medical schools. The decline in US graduates entering pathology has resulted almost entirely from a drop in the number of men choosing the field. In 1984, 286 male US graduates matched in pathology, but this number dropped to 150 in 1985 and 149 in 1986. The group entering in 1985 was the first who will need 5 years to be eligible for certification in the anatomic pathology/clinical pathology programs. During the same years, the 116 women who matched in 1984 were followed by 111 in 1985 and 100 in 1986. The effect of the American Board of Pathologys change in requirements is not easily analyzed. The figures for residents entering, given above, would suggest that the requirements discouraged men, especially, from entering the field. This hypothesis is supported by our questionnaire data and by anecdote concerning the pressure felt by graduating seniors to finish their postgraduate training as fast as they can and start paying off their average debt of

Recruitment of pathology residents: APC questionnaire results, 1987 and 1988

33,650. Pathology still seems to attract people who like to teach, study interesting case material, and do research. The percentage of PhD/MDs entering pathology is almost 10 times as high as their percentage among graduating seniors. Discouragement against entering pathology came from a perceived shortage of job openings, negative statements from other physicians (including pathologists), the addition of a fifth-year requirement, and lack of patient contact. The last is hard to account for because pathology would obviously not offer the opportunities to see patients that exist in the clinical specialties, but it was prominent in the concerns of residents answering our questionnaire. The picture that emerges from our data is one of a specialty passing through a difficult period in attracting new talent into its ranks. The first step in dealing with the problem would seem to be recognizing its existence.(ABSTRACT TRUNCATED AT 400 WORDS)

Physiologic and Morphologic Studies on Atherosclerotic Pigeons.

Our data show a persistent decline of US graduates entering pathology. Moreover, our data indicated that the NRMP provides only a small percentage of the total pathology slots ultimately filled. If the intentions of the 1988 cohort remain consistent, the predictions of Anderson et al concerning a shortage of community-hospital and private-laboratory pathologists seem to be well-founded. This evidence, coupled with the long-acknowledged shortage of academic pathologists, makes improved recruitment an imperative. Recent reports have described several potentially important recruitment tools. However, substantial change in recruitment needs to take place if significant shortages are to be avoided.

The Comparative Pathology of Nonhuman Primate Atherosclerosis

Summary Middle-aged White Carneau pigeons were found to have mean systolic blood pressures of 204 ± 2.3 mm of Hg and diastolic pressures of 140 ± 1.5 mm of Hg. Serum cholesterol levels were found to be 313 ± 7.19 mg% and serum triglyceride levels were 217 ± 11.83 mg%. The aortic atherosclerosis of these birds involved 12.88 ± 0.71% of the intima of the thoracic aorta. The mean per cent of arteries with atherosclerotic lesions in 15 frozen sections of left ventricle and septum of the heart were 6.6 ± 0.85%. The levels of blood pressure among White Carneau pigeons were found to account for very little of the variability in either aortic or coronary artery atherosclerosis. No sex difference could be found in the amount of coronary or aortic atherosclerosis. Serum cholesterol levels were found to be correlated with aortic atherosclerosis among male but not female birds. Serum cholesterol and triglyceride levels were correlated with coronary artery atherosclerosis among female but not male White Carneau pigeons.

Granuloma annulare: A rare occipital lesion in infants and children

The ideal animal model for atherosclerosis research would develop the lesions gradually during its lifetime and would develop clinical manifestations of the disease in late middle and old age. The atherosclerotic lesions of the ideal model would range from trivial abnormalities, such as fatty streaks, found only at necropsy, to raised plaques with complications such as ulceration, stenosis, hemorrhage and superimposed thrombosis. The number of animals developing such complicated lesions would ideally constitute about 20% of the population, with males developing complications more frequently than females, particularly in the coronary arteries. The clinically-significant lesions would be found first in the aorta, later in the coronary arteries and later still in the arteries supplying the brain. The end-organ complications of myocardial and cerebral infarction and gangrene of the extremities would be seen. Aneurysm formation in the aorta would develop occasionally. All of these things should take place in an animal sufficiently large to allow diagnostic and therapeutic measurements similar to those useful for human beings.