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Biomedical subjects

W C Roberts

Publications and source records attributed to W C Roberts.

At least 631 records · Page 35Linked to original sources
PubMed1976

The carcinoid endocardial plaque; an ultrastructural study.

Ultrastructural studies disclosed that the plaque-like endocardial thickenings in three patients with the carcinoid syndrome were composed of smooth muscle cells embedded in a stroma that was rich in acid mucopolysaccharides, collagen, and microfibrils, but devoid of elastic fibers. The smooth muscle cells contained variable numbers of myofilaments and cisterns of rough surfaced endoplasmic reticulum, and their basement membranes were greatly thickened, reduplicated, and arranged in layers. The endocardial plaques appeared histologically and ultrastructurally similar regardless of their location in the heart. The smooth muscle cells in these plaques appear to have been derived from primitive mesenchymal cells, which normally are present in the subendocardial endothelial space. These observations are interpreted as indicating that the plaques develop as a result of healing of a superficial endocardial injury, which may be initiated by release of bradykinin from hepatic metastases of a carcinoid tumor.

Endocardium↗
PubMed1976

Asymetric septal hypertrophy in childhood.

Although considerable information is available concerning the clinical features and natural history of asymmetric septal hypertrophy (ASH) in adults, little is known of this disease in children. The clinical characteristics and course of 46 children with ASH, who were evaluated at the National Heart and Lung Institute, have been analyzed. Twenty-four children had obstruction to ventricular outflow; 22 children had no obstruction to ventricular outflow, including 11 patients without overt manifestations of cardiac disease other than echocardiographic evidence of ASH. Thirty-five of the 46 children have been followed for one to 16 years (average 7.4 years). These latter children represent that subgroup of patients with ASH referred to the National Heart and Lung Institute and diagnosed prior to the general availability of echocardiography. The clinical course of these patients was variable. Fourteen (40%) of the 35 patients improved or remained stable, including four patients who received propranolol. Ten (29%) of the 35 patients deteriorated clinically and 11 (31%) of the 35 patients died suddenly (4% mortality per year). Two of the patients who died suddenly had previously undergone operation (six and 13 years previously) with resultant abolition of the outflow gradient; four others were taking propranolol. Neither symptomatology, electrocardiographic abnormalities, heart size, left ventricular ejection or upstroke time, magnitude of outflow gradient, or left ventricular end-diastolic pressure proved predictive of sudden death. Excluding patients who had previous operation, eight (40%) of 20 patients with obstruction who were followed long term and one (9%) of 11 patients without outflow obstruction died suddenly. Thus, the clinical and hemodynamic spectrum of ASH in childhood is broad. However, deterioration in clinical condition or sudden death has been relatively common in children with overt signs of cardiac disease.

Adolescent↗
PubMed1976

Atherosclerotic narrowing of the left main coronary artery. A necropsy analysis of 152 patients with fatal coronary heart disease and varying degrees of left main narrowing.

Histologic sections of the left main (LM) and the other three major coronary arteries were studied in 152 patients. The lumen of the LM in 35 patients was greater than 75% narrowed; in thirty, 50-75%; and in 87, less than 50% narrowed. The patients with greater than 75% narrowing were younger. Angina pectoris and hyperlipoproteinemia, specifically type II, were more common (P less than 0.02) and acute transmural and healed subendocardial myocardial infarcts were less frequent (P less than 0.05) in the patients with greater 75% LM narrowing than in those with less than 50% narrowing. Of the three other major coronary arteries, the average number narrowed in the patients with greater than 75% LM narrowing was 2.9; in those with 50-75% LM narrowing 2.7, and in those with less than 50% LM narrowing, 2.4. Of the 35 patients with greater than 75% LM narrowing, 33 had greater than 75% luminal narrowing of each of the other three major coronary arteries. Narrowing of the LM, therefore, indicates severe narrowing of usually all major coronary arteries.

Adult↗
PubMed1976

Valve ring abscess in active infective endocarditis. Frequency, location, and clues to clinical diagnosis from the study of 95 necropsy patients.

Analysis of 95 necropsy patients with active infective endocarditis (AIE) involving 128 native cardiac valves (aortic = 59, mitral = 48, tricuspid = 20, and pulmomic = 1) disclosed 27 patients with ring abscesses involving 30 valves: the aortic valve ring was infected in 24 patients and only an atrioventricular valve ring (mitral in two, and tricuspid in one) in three patients. Comparison of the following parameters showed no significant differences between the 27 patients with and the 68 patients without ring abscess: age, sex, antibiotic treatment or length of treatment, status of the cardiac valve(s) before infection, and the kind of infecting organism. Comparison of the following parameters, however, showed significant (P less than 0.05) differences between the 27 patients with and the 68 patients without valve ring abscess: 1) infection of the aortic valve; 2) occurrence of valvular regurgitation of recent origin; 3) presence of pericarditis; 4) presence of high degree of atrioventricular block; and 5) short duration of symptoms leading to severe debility or death. These five features, therefore, serve as a clinical clues to the presence of valve ring abscess in patients with AIE.

Abscess↗
PubMed1976

The coronary arteries and left ventricle in clinically isolated angina pectoris: a necropsy analysis.

Certain clinical and morphologic observations are described in 27 patients with severe isolated angina pectoris of either the stable (five patients) or the unstable form (22 patients). Twenty-four patients died during or shortly after cardiac operations designed to relieve angina pectoris and three died during cardiac catheterization. During life none had had clinical evidence of acute myocardial infarction or congestive cardiac failure. At necropsy, each had diffuse, extensive coronary atherosclerosis with severe luminal narrowing: the lumens of at least two, an average of three, of the four major epicardial coronary arteries were narrowed greater than 75% in cross-sectional area by old atherosclerotic plaques. Despite the severe coronary narrowing, there was little myocardial damage. Left ventricular scarring (excluding papillary muscle) was observed grossly in only 14 (52%) of the 27 patients and in each it involved only a small portion of myocardial wall. The left ventricular cavity was of normal size in all except two patients. The hearts were of normal weight in 15 (56%) patients, and the average increase above the upper range of normal for the other 12 hearts was 19%. Thus, clinically isolated, severe angina pectoris is associated with severe, diffuse luminal narrowing but relatively little myocardial damage.

Adult↗
PubMed1976

Tunnel subaortic stenosis: left ventricular outflow tract obstruction produced by fibromuscular tubular narrowing.

The clinical and morphologic features of tunnel subaortic stenosis, an unusual form of obstruction to left ventricular outflow, are described in 11 patients. Although patients with tunnel subaortic stenosis demonstrate a variety of cardiovascular malformations, the most characteristic anatomic feature is fibromuscular tubular narrowing of the outflow tract that remains relatively unchanged during the cardiac cycle. The aortic anulus was abnormally small in six of the 11 patients, including one who also had a hypoplastic ascending aorta. Evidence of a small mitral orifice was present in two patients, and two other patients had asymmetric septal hypertrophy. Although operation was successful in significantly reducing the outflow gradient in two of the seven operated patients, all seven patients had gradients of 50 mm Hg or more at the most recent postoperative evaluation. Three patients (two with previous operation) died suddenly; each of these patients had mild or no symptoms. Because of the apparent ineffectiveness of current operative methods in patients with tunnel subaortic stenosis, it is important to differentiate this condition from obstructions to left ventricular outflow.

Adolescent↗
PubMed1976

Site of myocardial infarction. A determinant of the cardiovascular changes induced in the cat by coronary occlusion.

The influence of site of acute myocardial infarction on heart rate, blood pressure, cardiac output, total peripheral resistance (TPR), cardiac rhythm, and mortality was determined in 58 anesthetized cats by occlusion of either the left anterior descending (LAD), left circumflex or right coronary artery. LAD occlusion resulted in immediate decrease in cardiac output, heart rate, and blood pressure, an increase in TPR, and cardiac rhythm changes including premature ventricular beats, ventricular tachycardia, and occasionally ventricular fibrillation. The decrease in cardiac output and increase in TPR persisted in the cats surviving a ventricular arrhythmia. In contrast, right coronary occlusion resulted in a considerably smaller decrease in cardiac output. TPR did not increase, atrioventricular condition disturbances were common, and sinus bradycardia and hypotension persisted in the cats recovering from an arrhythmia. Left circumflex ligation resulted in cardiovascular changes intermediate between those produced by occlusion of the LAD or the right coronary artery. Mortality was similar in each of the three groups. We studied the coronary artery anatomy in 12 cats. In 10, the blood supply to the sinus node was from the right coronary artery and in 2, from the left circumflex coronary artery. The atrioventricular node artery arose from the right in 9 cats, and from the left circumflex in 3. The right coronary artery was dominant in 9 cats and the left in 3. In conclusion, the site of experimental coronary occlusion in cats is a major determinant of the hemodynamic and cardiac rhythm changes occurring after acute myocardial infarction. The cardiovascular responses evoked by ligation are related in part to the anatomical distribution of the occluded artery.

Animals↗
PubMed1976

Idiopathic pulmonary fibrosis. Clinical, histologic, radiographic, physiologic, scintigraphic, cytologic, and biochemical aspects.

Idiopathic pulmonary fibrosis is a fatal disorder that starts as an alveolitis and progresses to interstitial fibrosis. Correlative morphologic, physiologic, and biochemical studies in 29 patients have shown that the inflammatory process in best followed by serial bronchoalveolar lavage and 67 Ga citrate scanning, and the fibrotic process is best followed by quantitation of the exercise-induced drop in arterial oxygen tension per unit of oxygen consumed. Although biopsies in idiopathic pulmonary fibrosis seem to show increased amounts of fibrotic tissue, biochemical studies suggest that the disease is probably one of collagen rearrangement rather than collagen increase. Perhaps becasue of this, peripheral lymphocytes of these patients recognize collagen as "non-self" and, when exposed to it in vitro, produce lymphokines and cell lysis. The fibrotic process is probably irreversible, but the inflammatory and immune processes that cause it may be amenable to therapy if diagnosed early.

Adult↗
PubMed1976

Pericardial heart disease: a study of its causes, consequences, and morphologic features.

This report reviews morphologic aspects of pericardial heart disease. A morphologic classification for this condition is presented. An ideal classification of pericardial heart disease obviously would take into account clinical, etiologic and morphologic features of this condition but a single classification combining these three components is lacking. Pericardial heart disease is relatively uncommon clinically, and when present at necropsy it usually had not been recognized during life. The term "pericarditis" is inaccurate because most pericardial diseases are noninflammatory in nature. Morphologically chronic pericardial heart disease may present clinically as an acute illness. Even when clinical symptoms are present, however, few patients develop evidence of cardiac dysfunction (constriction). When pericardial constriction occurs, it is the result of increased pericardial fluid or increased pericardial tissue or both. Increased fluid is treated by drainage; increased tissue is treated by excision. In most patients with chronic constrictive pericarditis the etiology is not apparent even after histologic examination of pericardia.

Adult↗
PubMed1976

Tension on coronary bypass conduits. A neglected cause of real or potential obstruction of saphenous vein grafts.

Of 41 saphenous vein aorta-coronary bypass grafts from 21 patients, abnormal graft tension was judged to be present at necropsy in 6 grafts (15 per cent) from 5 patients (24 per cent). Five (33 per cent) of 15 grafts placed to the right coronary system and one (3 per cent) of 26 grafts to the left coronary system were under excess tension. The abnormal tension appeared to result from the insertion of grafts too short to accommodate normal or abnormal distention of the right atrium and ventricle (graft to distal right coronary or posterior descending coronary artery) or of the pulmonary trunk (graft to left coronary system) after discontinuation of cardiopulmonary bypass or development of acute congestive cardiac failure.

Cardiopulmonary Bypass↗
PubMed1976

Histologic changes in saphenous vein aorta-coronary bypass grafts. The effect of the angle of the aortic anastomosis.

Thirteen dogs were subjected to bypass grafting from the aorta to the left circumflex coronary artery with the saphenous vein to determine whether the angle of insertion of the saphenous vein into the aorta influences the functional and histologic fate of the grafts. The angle of the aortic anastomosis was obtuse in 6 dogs, acute in 5, and perpendicular in 2. Histologic examination of all 13 grafts 6 to 19 months (mean 9.4) postoperatively showed fibrous intimal proliferative lesions of variable severity along the entire length of the grafts, occasionally with extension into the native coronary arteries. Loss of medical smooth muscle and adventitial fibrosis also occurred in all 13 grafts. The extent and severity of these changes, however, were not related to the angle aortic anastomosis.

Animals↗
PubMed1976

Spherical microparticles in human myocardium: an ultrastructural study.

Clusters of spherical microparticles (SMP) that averaged 500 A in diameter and were composed of dense cores surrounded by single trilaminar membranes were found in operatively obtained myocardial biopsies from 29 of 70 patients with various types of heart diseases including: left atrial myocardium (14 patients) and right atrial myocardium (four patients) of 14 patients with mitral valvular disease; left ventricular myocardium of three of 16 patients with aortic valvular disease, three of 16 patients with hypertrophic cardiomyopathy, and two of four patients with combined mitral and aortic valvular disease; and crista supraventricularis muscle of seven of 20 patients with congenital heart diseases associated with muscular obstruction to right ventricular outflow. SMP were consistently associated with interstitial fibrosis and with degeneration of the muscle cells. SMP occurred along the outer surfaces on the sides and free ends of muscle cells in areas of fibrosis, in the widened spaces between membranes of partially dissociated intercellular junctions, and within cytoplasmic vesicles considered to be phagocytic. SMP frequently were joined together by minute nexuses that were structurally identical with those forming parts of intercellular junctions of muscle cells. Evidence is presented to show that SMP occur commonly in tissues other than myocardium. It is concluded that SMP form in the heart as part of a process that mediates the remodeling of cellular surfaces, especially those of intercellular junctions undergoing dissociation.

Cardiomegaly↗