Search PubMed⌕ Search

Biomedical subjects

W C Roberts

Publications and source records attributed to W C Roberts.

At least 613 records · Page 34Linked to original sources
PubMed1977

Morphology of canine hearts after 24 hours' preservation and orthotopic transplantation.

Ten dogs underwent orthotopic cardiac transplantation after preservation of the donor heart for 24 hours in an oxygenated hypothermic, hypertonic, intracellular solution, either with (five dogs) or without (five dogs) continuous, oxygenated, low-pressure perfusion. Eight dogs survived for 24 hours after transplantation, at which time they were put to death. The two nonsurvivors were among the five with nonperfused hearts. Examination of all 10 donor hearts showed differences between the two groups: Four of five nonperfused hearts showed severe transmural myocardial coagulation necrosis but only small foci of contraction band necrosis (myofibrillar degeneration). The perfused hearts, however, showed more extensive subendocardial areas of contraction-band necrosis, but only minimal and focal coagulation necrosis, indicating less severe hypoxic damage. These results indicate that oxygenated perfusion with a hypothermic, hypertonic, intracellular solution may permit improved transplant survival after extended cardiac preservation.

Animals↗
PubMed1977

Morphologic observations in biologic conduits between aorta and coronary artery.

This report describes morphologic observations in autogenous saphenous veins, autogenous internal mammary arteries, radial arteries and arterial heterografts used as aortocoronary bypass conduits. The normal or expected changes and the abnormal or unexpected changes observed in each type of bypass conduit is discussed. The three major changes seen in saphenous vein grafts in the aortocoronary position are: (1) medial fibrous replacement; (2) adventitial fibrous proliferation; and (3) intimal fibrous proliferation. Medial fibrous replacement is the result of vein wall ischemia and necrosis and ultimately replacement of smooth muscle cells; adventitial fibrosis is the result of organization of fibrin and red cell clot and repair of ischemic damage. The cause of intimal fibrous proliferation is unclear but appears to be the result of chronic repair of injured intima and endothelium. That the severity of the changes varies along the length of one graft or among grafts in the same patient suggests that other factors contribute to the development of the changes observed. Although some structural changes have been observed, internal mammary arteries are relatively resistant to the changes seen in saphenous veins. Radial arterial grafts have shown severe structural changes with time, to a degree greater than that seen in the saphenous vein grafts. Heterograft conduits so far have been unsuccessful in the aortocoronary position in humans. The severe changes seen in radial artery and heterograft conduits indicate that they are inadequate for use as substitutes for saphenous vein and mammary artery as bypass conduits from aorta to coronary artery.

Adult↗
PubMed1977

Histologic and ultrastructural features of primary and secondary endocardial fibroelastosis.

The average size of elastic fibers in thickened left ventricular endocardium was much larger in four patients with congenital endocardial fibroelastosis (EFE) than in six patients with acquired EFE (secondary to ischemic heart disease in two patients, to prosthetic cardiac valves in three, and to irradiation of the chest in one). Both components of normal elastic tissue (central, amorphous cores, and peripheral microfibrils) were present in endocardial elastic fibers of each patient. Ultrastructural identification of elastic fibers was greatly facilitated by staining with silver tetraphenylporphin sulfonate.

Adult↗
PubMed1977

A hitherto undescribed cause of prosthetic mitral valve obstruction.

A case is described in which severe prosthetic mitral valve obstruction was produced by entanglement of sutures across the central axis of the prosthesis on its ventricular side. The entangled sutures prevented the tilting disc occluder from falling into the left ventricular cavity during ventricular diastole.

Adult↗
PubMed1976

Choosing a substitute cardiac valve: type, size, surgeon.

Certain ideal characteristics of substitute cardiac valves are analyzed for each of the four basic types of available substitute cardiac valves. Of the four, the caged disc prosthesis is the least desirable: it obstructs, it clots and it degenerates. Each of the other three types of substitute cardiac valves has more favorable characteristics. Ideally, the caged ball prosthesis might be limited to patients with predominantly regurgitant lesions because of the problem of prosthetic disproportion. The tilting disc has favorable hemodynamic and wear characteristics, but long-term anticoagulant therapy is essential, as with the caged ball and caged disc types of prosthesis. The porcine xenograft appears to be desirable, but patients with sufficient implantation time (more than 5 years) for proper evaluation are just beginning to be studied and, therefore, final judgment must be reserved. Assuming that valve replacement is to be carried out in a large medical center by a surgical team experienced in this procedure, the results of this operation today are dependent more on the type and size of substitute valve inserted than on the surgeon who inserts the valve. It is therefore important for the cardiologist to become more informed about the various types of prosthetic cardiac valves and to become a member of the team deciding which type and size of cardiac valve are most suitable for his (or her) patient.

Animals↗
PubMed1976

Intravenous injection of talc-containing drugs intended for oral use. A cause of pulmonary granulomatosis and pulmonary hypertension.

Clinical and morphologic features are described in two patients known to have repeatedly injected intravenously talc-containing drugs intended for oral use. In one patient severe pulmonary hypertension developed; the talc granulomas in him were located predominantly within the pulmonary arteries. The second patient had normal pulmonary arterial pressures, and the talc granulomas in him were located predominantly in the pulmonary interstitium. Of 19 previously described patients with pulmonary talc granulomas, 12 had morphologic evidence of pulmonary hypertension (in three of severe degree); in each, talc granulomas were located predominantly within the pulmonary arteries. In those without signs of pulmonary hypertension, granulomas were located predominantly in the pulmonary interstitium. Why there are differences in the distribution of the talc granulomas is unclear. It is clear, however, as demonstrated by one of our patients, that severe pulmonary hypertension may be a consequence of intravenous injection of drugs intended for oral use.

Adolescent↗
PubMed1976

Congenital obstructive lesions involving the major pulmonary veins, left atrium, or mitral valve: a clinical, laboratory, and morphologic survey.

The clinical, laboratory, and morphologic features of congenitally obstructive lesions causing pulmonary venous hypertension are reviewed. These lesions are responsible for considerable infant mortality and morbidity, especially in the first weeks of life, are not infrequently encountered in older children, and are occasionally seen in adults. The presence of a malformation causing pulmonary venous hypertension often can be detected clinically, but precise anatomical and physiological diagnoses, usually necessary for optimal patient management, often can be made only by detailed laboratory study. Cardiac catheterization and angiocardiography remain the prime modes of accurate diagnosis in such patients, many of whom have other significant cardiovascular malformations, and echocardiography is an extremely useful adjunct, especially in patients with mitral valvular stenosis, hypoplasia, or atresia. The only definitive treatment in any of these patients is operative relief of the obstruction, and the chances of success depend not only on the skill of the surgeon, but also on the nature of the obstructing lesion, the types of associated malformations, and the precision with which these are defined preoperatively.

Adult↗
PubMed1976

Prosthetic valve endocarditis: clinicopathologic analysis of 22 necropsy patients with comparison observations in 74 necropsy patients with active infective endocarditis involving natural left-sided cardiac valves.

Clinical and morphologic features are described in 22 necropsy patients with endocarditis involving rigid-framed prosthetic valves: aortic in 15 patients and mitral in 7. The interval from valve replacement to onset of symptoms of prosthetic valve endocarditis was less than 2 months in 8 patients and longer than 2 months in 14 patients. The most frequent infecting organism was the Staphylococcus (13 patients). In each of the 22 patients the infection was located behind the site of attachment of the prosthesis to the valve ring, and the infection spread to adjacent structures in 13 patients, 11 of whom had aortic prostheses. Prosthetic detachment causing severe regurgitation occurred in 12 of the 15 patients with an infected aortic valve prosthesis, and in 2 of the 7 with an infected mitral valve prosthesis. Prosthetic obstruction by vegetative material occurred in 5 of 7 patients with prosthetic mitral infection and in only 1 of 15 with prosthetic aortic infection. High degrees of conduction defects developed in seven patients with aortic prosthetic valve endocarditis: complete heart block in five, and complete left bundle branch block in two. Comparison of observations in the 22 patients with prosthetic valve endocarditis with those in 74 patients with active infective endocarditis involving natural left-sided cardiac valves revealed significant (P less than 0.05) differences in the percent with ring abscess, hemodynamic consequences of the endocarditis (valve stenosis), frequency of Staphylococcus as the causative organism and percent with complete heart block or left bundle branch block. No significant differences were observed between the two groups when comparing age, sex, type of underlying valve disease or frequency of organ infarcts of splenomegaly.

Abscess↗
PubMed1976

Prolapse of the mitral valve is described in two patients with the Ebstein's anomaly of the tricuspid.

Prolapse of the mitral valve is described in two patients with the Ebstein's anomaly of the tricuspid valve. This association has not been described previously. It is probable, however, that this association is not a rare one, but that clinical features of the prolapsing mitral valve are obscured by those resulting from the malformed tricuspid valve. Opportunity also was provided to study anatomically the mitral valve of a patient known to have a systolic click and a late systolic murmur (the Barlow syndrome). Although there have been several anatomic descriptions of floppy mitral valve at necropsy, they have been extremely rare in patients known to have the classic auscultatory features of the Barlow syndrome.

Adolescent↗
PubMed1976

Aortic valve atresia: a new classification based on necropsy study of 73 cases.

Certain clinical and morphologic observations are described in 73 necropsy patients with aortic valve atresia. The mean age at death was 5 days; 80 percent died during the first week of life, and 70 percent were boys. Of the 73 patients, 69 (95 percent) had a hypoplastic left ventricle with intact ventricular septum and either an atretic (25 patients) or hypoplastic (44 patients) mitral valve. The other four patients had a well developed left ventricle with one or more defects in the ventricular septum and either an atretic (one patient) or well developed (three patients) mitral valve. Review of previous reports on aortic valve atresia disclosed that a well developed left ventricle or ventricular septal defect in association with absence of the aortic valve was extremely rare. A new classification for aortic valve atresia is presented based on the status of the ventricular septum, which in turn appears to determine the size of the left ventricular cavity. The predilection for male subjects for all types of aortic valve disease, including atresia, is emphasized.

Aortic Valve↗
PubMed1976

The heart in the Hurler syndrome: gross, histologic and ultrastructural observations in five necropsy cases.

Clinical and morphologic features of the cardiovascular system are described in five necropsy patients with the Hurler syndrome. In all five patients the coronary arteries, four cardiac valves, mural endocardium of all four chambers, myocardial walls and aorta were affected in a characteristic manner. All of these sites contained large clear cells known as Hurler cells (readily visible by light microscopy). In addition, granular cells were observed in semi-thin (1 mu) sections and by electron microscopy in the coronary arteries, atrioventricular (A-V) valves and in myocardial interstitium. These latter cells appear to produce collagen in an abnormal way and are probably responsible for the heavy deposits of collagen in the cardiovascular system of patients with the Hurler syndrome. In the cardiac muscle cells, in smooth muscle cells of the coronary arteries and in fibroblasts, wherever located, deposits of acid mucopolysaccharides and glycolipids usually were also observed. The acid mucopolysaccharide deposits were observed easily with light microscopy except in the cardiac muscle cells where they were seen only with electron microscopy. The glycolipid depositis, observed only on examination of 1 mu thick sections or with electron microscopy, have not previously been observed in coronary arteries or in myocardial cells. The infiltration into the heart by these cells and deposits in all five patients resulted in severe narrowing of the extramural coronary arteries, considerable thickening of the cardiac valves (the left-sided more than the right-sided valves), generalized thickening of mural endocardium and "stiffening" of the myocardial walls. Thus, the cardiovascular lesions in the Hurler syndrome are specific and life-threatening.

Adolescent↗
PubMed1976

Coronary heart disease after mediastinal irradiation for Hodgkin's disease.

Attention is called to the development of coronary heart disease in two patients several years after they received mediastinal irradiation for Hodgkin's disease. One patient, a 33 year old man, died suddenly eight years after irradiation; necropsy disclosed marked narrowing of all three major coronary arteries. In addition to severe intima fibrous thickening, there also was considerable adventitial scarring of the coronary arteries. This type of coronary sclerosis is different from that seen in the usual patient with coronary heart disease. The second patient, a 42 year old man, had an acute myocardial infarction on two occasions, the first six years after mediastinal irradiation. Observations in previously described patients with coronary heart disease almost surely induced by therapeutic irradiation for Hodgkin's disease are reviewed.

Adult↗